Particle separating system

Abstract

A particle separating system for supplying a cam shaft phase adjuster with cleaned lubricating oil. The phase adjuster includes a stator, a rotor connectable to a cam shaft, and a control valve for hydraulically adjusting the rotational angular position of the rotor relative to the stator. The particle separating system includes an oil separator arranged in the flow of the lubricating oil, upstream of an oil gallery of an engine supplied with the lubricating oil, exhibiting a separation efficiency of at least 50% for particles having a size P1 and a separation efficiency of at least 90% at a size P2>P1; a particle separator arranged downstream of the oil separator and upstream of the phase adjuster or control valve, to clean the lubricating oil for the phase adjuster. The particle separator exhibits a separation efficiency of 50% at a size P3, where P1<P3<100 m.

Claims

1. A particle separating system for supplying a hydraulic cam shaft phase adjuster with cleaned engine lubricating oil as a pressure medium, wherein the cam shaft phase adjuster comprises a stator which can be rotary-driven, a rotor which is or can be connected to a cam shaft, and a control valve for hydraulically adjusting the rotational angular position of the rotor relative to the stator, the particle separating system comprising: a main oil separator which is arranged in the flow of the engine lubricating oil, upstream of a lubricating oil gallery of an internal combustion engine which is to be supplied with the engine lubricating oil, and which exhibits a separation efficiency of at least 50% for particles having a particle size P1 and a separation efficiency of at least 90% at a particle size P2>P1; and a particle separator which is arranged downstream of the main oil separator and upstream of the cam shaft phase adjuster or control valve, in order to clean the engine lubricating oil for the cam shaft phase adjuster, wherein the particle separator exhibits a separation efficiency of 50% at a particle size P3, where P1<P3<100 m, and wherein the separation efficiency of the particle separator is at most 30% at the particle size P2.

2. The particle separating system according to claim 1, wherein the particle separator exhibits a separation efficiency of at least 90% at a particle size P4, where P2<P4<100 m.

3. The particle separating system according to claim 1, wherein the separation efficiencies apply at least to particles made of a material from the group of materials consisting of sand, corundum, metal and metal alloys, wherein the metal and the metal alloys can in particular be iron, iron-based alloys, aluminium and aluminium-based alloys.

4. The particle separating system according to claim 1, wherein the particle separator comprises a first separating stage for separating particles and, downstream of the first separating stage, a second separating stage for separating particles, and wherein at least the first separating stage and optionally also the second separating stage is arranged upstream of the cam shaft phase adjuster or upstream of the control valve in the flow direction of the engine lubricating oil.

5. The particle separating system according to claim 4, wherein the second separating stage is configured to separate smaller particles than the first separating stage.

6. The particle separating system according to claim 4, wherein the second separating stage, comprises a filter structure, and the filter structure comprises a filter medium, which the engine lubricating oil can flow through, for trapping particles contained in the engine lubricating oil, wherein the filter medium can in particular be pleated.

7. The particle separating system according to claim 6, wherein the filter medium surrounds a longitudinal axis of the filter structure, for example over a circumferential angle of 360, and is cylindrical or widens, for example conically, in the longitudinal direction of the filter.

8. The particle separating system according to claim 6, wherein the engine lubricating oil can be fed to the cam shaft phase adjuster through a hollow space which is delineated by one or more bodies, and wherein: a flow channelling device is provided which imbues the engine lubricating oil with a rotational impulse about a longitudinal axis which is central in relation to the hollow space as it flows into the hollow space and/or as it flows through the hollow space, and/or a body which delineates the hollow space is a rotary body which rotates about a longitudinal axis which is central in relation to the hollow space when the cam shaft phase adjuster is in operation.

9. The particle separating system according to claim 8, wherein filter structure is arranged in the hollow space.

10. The particle separating system according to claim 8, the first separating stage, comprises a centrifugal force separator, which extends around the central longitudinal axis in the hollow space, for absorbing and trapping particles which enter the centrifugal force separator due to centrifugal force.

11. The particle separating system according to claim 10, wherein the centrifugal force separator lines a circumferential wall surrounding the hollow space on the radially outer side and/or forms absorbing pockets for particles with the circumferential wall, and/or the circumferential wall comprises a structured surface (81) for trapping particles.

12. The particle separating system according to claim 10, wherein the centrifugal force separator exhibits an axial length of at least 20 cm or at least 30 cm or at least 40 cm.

13. The particle separating system according to claim 8, wherein the flow channelling device comprises an inlet of the hollow space, and the inlet is embodied such that the engine lubricating oil flows into the hollow space with a directional component which is tangential in relation to the central longitudinal axis.

14. The particle separating system according to claim 8, wherein the flow channelling device comprises one or more deflecting structures in the hollow space which deflect/s the engine lubricating oil in the hollow space in a direction which is tangential with respect to the central longitudinal axis.

15. The particle separating system according to claim 8, wherein the hollow space extends in the stator near an outer circumference of the stator, and the rotational axis of the stator forms the longitudinal axis which is central in relation to the hollow space.

16. The particle separating system according to claim 1, wherein the particle separator comprises a cyclone separator, and the cyclone separator comprises: a vortex portion exhibiting a cyclone axis and comprising an inlet for an inflow of the engine lubricating oil with a tangential directional component with respect to the cyclone axis; an axial separating portion, connected to the vortex portion, for absorbing particles flowing axially in the vortex portion towards the separating portion; and an outlet for the lubricating oil.

17. The particle separating system according to claim 16, wherein a pressure storage for the lubricating oil, which is arranged upstream of the cam shaft phase adjuster, forms the cyclone separator.

18. The particle separating system according to claim 1, wherein: the engine lubricating oil can be fed to the cam shaft phase adjuster through a hollow space which extends around a rotational axis and is delineated on the radially inner side by a first body and on the radially outer side by a second body which surrounds the first body; at least one of the bodies can be rotary-driven about the rotational axis absolutely and relative to the other body; the hollow space forms and/or contains a centrifugal force separator for absorbing particles entering the centrifugal force separator due to centrifugal force; and an annular gap remains between the first body and the second body downstream of the centrifugal force separator, wherein the annular gap extends around the rotational axis and delineates the hollow space, and the lubricating oil has to flow through the annular gap on its way to the cam shaft phase adjuster.

19. The particle separating system according to claim 1, wherein the particle separator comprises magnetic material for trapping ferritic particles.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described below on the basis of example embodiments. Features disclosed by the example embodiments advantageously develop the subject-matter of the claims, the subject-matter of the aspects and also the embodiments described above. There is shown:

(2) FIG. 1 a lubricating oil cycle comprising a particle separating system in accordance with the invention;

(3) FIG. 2 a particle separating system comprising multiple particle separators for a system of multiple phase adjusters;

(4) FIG. 3 a particle separating system comprising one particle separator for multiple phase adjusters;

(5) FIG. 4 separation curves of a main oil separator and an additional particle separator of the particle separating system;

(6) FIG. 5 a phase adjuster comprising a particle separator of a first example embodiment;

(7) FIG. 6 the particle separator of FIG. 5 in an enlarged representation;

(8) FIG. 7 the cross-section A-A from FIG. 5;

(9) FIG. 8 the cross-section B-B from FIG. 5;

(10) FIG. 9 an alternative centrifugal force separator;

(11) FIG. 10 a support structure of a reflux valve of the phase adjuster in FIG. 5;

(12) FIG. 11 a particle separator of a second example embodiment;

(13) FIG. 12 the cross-section A-A from FIG. 11;

(14) FIG. 13 the cross-section B-B from FIG. 11;

(15) FIG. 14 a particle separator of a third example embodiment;

(16) FIG. 15 the cross-section A-A from FIG. 14;

(17) FIG. 16 a particle separator of a fourth example embodiment;

(18) FIG. 17 a particle separator of a fifth example embodiment;

(19) FIG. 18 the particle separator of the fifth example embodiment, in a cross-section; and

(20) FIG. 19 an arrangement of structures for feeding lubricating oil to the particle separator of the fifth example embodiment.

DETAILED DESCRIPTION OF THE INVENTION

(21) FIG. 1 shows a lubricating oil cycle for supplying an internal combustion engine with engine lubricating oil. The lubricating oil cycle comprises a lubricating oil reservoir S and a lubricating oil pump 1 which delivers engine lubricating oil from the lubricating oil reservoir S to consumption points 5.sub.i via a lubricating oil gallery 5, in order for example to lubricate a consumption point 5.sub.i and to cool, for example by means of spray cooling, and as applicable likewise lubricate a consumption point 5.sub.n. Once it has lubricated and/or cooled the relevant consumption point 5.sub.i, the lubricating oil flows back into the lubricating oil reservoir S.

(22) A cam shaft phase adjuster 10, referred to in the following as the phase adjuster 10, or a system of multiple phase adjusters 10 adjoins the lubricating oil cycle as an additional lubricating oil consumer. The engine lubricating oil serves as a pressure medium for the respective phase adjuster 10 for adjusting the phase position of a cam shaft, which is assigned to the respective phase adjuster, relative to a crankshaft of the internal combustion engine. The pump 1 delivers the lubricating oil to the consumption points 5.sub.i and the phase adjuster(s) 10 via a cooler 2 and a main oil separator 3, as is common in motor vehicles. A secondary flow oil separator, which can in particular be configured for separating soot particles, is denoted by 4.

(23) A particle separating system which is integrated into the lubricating oil cycle of the internal combustion engine ensures very reliably that lubricating oil from which damaging or acutely compromising dirt particles have to the greatest possible extent been removed is fed to the phase adjuster 10 as a pressure medium. The whole of the delivery flow of the lubricating oil pump 1 is delivered through the main oil separator 3 before the lubricating oil reaches the individual consumption points 5.sub.i and the phase adjuster 10 via the lubricating oil gallery 5. Dirt particles down to particle sizes of 50 m and smaller are separated in the main oil separator 3. The lubricating oil at the outlet of the main oil separator 3, which has been cleaned in the main oil separator 3, therefore at least substantially only then exhibits dirt particles smaller than 50 m. Main oil separators 3 such as are common in motor vehicles achieve a separation efficiency of 90% and higher at particle sizes in the range of 30 m to 40 m. The main oil separator 3 therefore comprises one or more correspondingly fine separating devices.

(24) Because of the drop in pressure associated with cleaning, a bypass valve 3a is provided in order to deliver the lubricating oil past the main oil separator 3, and thus unfiltered, to the consumption points 5.sub.i when the engine is still cold, i.e. during a cold start. The bypass valve 3a protects the main oil separator 3 from being destroyed by the particularly high pressure at the outlet of the lubricating oil pump 1 when cold. Once the lubricating oil has been sufficiently heated by the operation of the internal combustion engine, the bypass valve 3a closes and the lubricating oil flows through the main oil separator 3 to the consumption points 5.sub.i and the phase adjuster 10.

(25) In FIG. 1, the consumption points 5.sub.i and the phase adjuster 10 are arranged in parallel in relation to the lubricating oil flow, such that the lubricating oil flows from the main oil separator 3 up to the respective consumption point 5.sub.i and the phase adjuster 10, respectively, through only the essential feed conduits. In principle, a consumption point 5.sub.i can however also be arranged upstream of the phase adjuster 10. It is equally possible for a consumption point 5.sub.i to be arranged downstream of the phase adjuster 10, such that the lubricating oil is fed to the phase adjuster 10 via the upstream consumption point 5.sub.i and/or fed back into the lubricating oil reservoir S from the phase adjuster 10 via the downstream consumption point 5.sub.i.

(26) In addition to the main oil separator 3, a particle separator 20 is provided in the lubricating oil feed to the phase adjuster 10, in order to increase the likelihood, as compared to known separating systems, with which it is ensured that malfunctions due to dirt particles and in principle also frictional wear on the phase adjuster 10 no longer occur. The particle separator 20 is thus arranged downstream of the main oil separator 3 and upstream of the phase adjuster 10. The particle separator 20 can in particular be arranged immediately upstream of the phase adjuster 10, such that the lubricating oil from which potentially damaging dirt particles have to the greatest possible extent been removed by the particle separator 20 is directly available to the phase adjuster and does not flow to the phase adjuster 10 indirectly via long feed conduits or even an interposed consumption point.

(27) The particle separator 20 is arranged at least in part upstream of the phase adjuster 10. This means that at least some of the particle separator 20 is arranged upstream of a pressure port of the phase adjuster 10. If the particle separator 20 comprises multiple separating stages which are connected successively in relation to the flow direction of the lubricating oil, at least one of the separating stages is arranged upstream of the pressure port of the phase adjuster 10. A separating stage or some of a separating stage of a multi-stage particle separator 20 can in principle be arranged in the phase adjuster 10 and for example protrude through the pressure port of the phase adjuster 10 into a control valve of the phase adjuster 10; expediently, however, the particle separator 20 is arranged entirely outside the phase adjuster 10. Arranging it at least in part and preferably entirely outside the phase adjuster 10 enables the particle separator 20 to be configured independently of restrictions which filter screens which are conventionally arranged in phase adjusters are subject to due to the very limited installation spaces available in phase adjusters. This opens up hitherto unused scope for configuring the particle separator 20 in accordance with the separating properties of the main oil separator 3 which likewise forms part of the particle separating system.

(28) FIG. 2 shows a system of multiple phase adjusters 10 which are each assigned a particle separator 20 of their own. The statements made above with respect to FIG. 1 apply to each pair consisting of a phase adjuster 10 and an assigned particle separator 20. The phase adjusters 10 and particle separators 20 of FIG. 2 can substitute for the phase adjuster 10 and particle separator 20 in FIG. 1. Two phase adjusters 10 and correspondingly two particle separators 20 are shown by way of example in FIG. 2. If the internal combustion engine comprises more than two cam shafts which can be adjusted in terms of their rotational angular position, and correspondingly more than two phase adjusters 10, then each of the phase adjusters 10 in a correspondingly extended system of phase adjusters 10 can be assigned a particle separator 20 of its own, as shown in FIG. 2 for two phase adjusters 10 only.

(29) FIG. 3 shows a system of multiple phase adjusters 10 which, unlike the system in FIG. 2, is only assigned one, shared particle separator 20. The system shown comprises two phase adjusters 10 only. If the system comprises more than two phase adjusters 10, then the three or more phase adjusters 10 can be supplied with the lubricating oil which has been cleaned by the shared particle separator 20. The system of phase adjusters 10 comprising the shared particle separator 20 can substitute for the phase adjuster 10 and particle separator 20 in the lubricating oil cycle of FIG. 1.

(30) If a system of phase adjusters 10 comprises three or more phase adjusters 10, hybrid forms of the arrangements shown in FIGS. 2 and 3 are also possible with regard to supplying the phase adjusters with cleaned lubricating oil. If there are for example three phase adjusters 10, then two phase adjusters 10 can be supplied via a shared particle separator 20, as in FIG. 3, and the third phase adjuster 10 can be supplied via a particle separator 20 of its own which is only assigned to that phase adjuster, as in FIG. 2. If there are four phase adjusters 10, each two of these phase adjusters 10 can for example be combined to form a group, as in FIG. 3, and respectively supplied with the cleaned lubricating oil via a shared particle separator 20.

(31) FIG. 4 shows the separation curve A3 of the main oil separator 3, separation curves A20, A20 and A20 for one particle separator 20 each and, for comparison, the separation curve AFP of a filter screen such as is typically arranged in the phase adjuster in the prior art. The separation curves show the separation efficiency as a percentage against the particle size P at which the respective separation efficiency is achieved, i.e. as a function of P. In relation to the separation curve A3, this means that the main oil separator 3 exhibits a separation efficiency of 50% for dirt particles of the particle size P1 and a separation efficiency of almost 100% for dirt particles of the size P2. If lubricating oil flows through the main oil separator 3 when the internal combustion engine is at its operating temperature, 50% of the particles of particle size P1 contained in the lubricating oil and almost 100% of the particles of particle size P2 will be trapped in the main oil separator 3, while 50% of the particles of particle size P1 and a higher percentage of even smaller particles will flow through the main oil separator 3 and enter the lubricating oil gallery 5 (FIG. 1). The particle size P1 can for example be in the range of 10 m to 20 m and in particular in the range of 12 m to 15 m. The particle size P2 can for example be in the range of 30 m to 50 m and in particular in the range of 30 m to 40 m. This corresponds to the separation efficiencies of main oil separators 3 such as are common in motor vehicle manufacturing.

(32) The separation curves A20, A20 and A20 show ways of attuning the particle separator 20 to the separating properties of the main oil separator 3.

(33) The separation curve A20 overlaps with the separation curve A3. If the particle separator 20 exhibits the separation curve A20, even very small dirt particles which flow through the main oil separator 3 will therefore be separated to a measurable extent in the particle separator 20. An appreciable separation takes effect even for particles having a particle size which is between P1 and P2.

(34) The separation curve A20 is offset some way from the separation curve A3. This means that a particle separator 20 which exhibits the separation curve A20 will only separate dirt particles to a measurable extent at or above a particle size which is above the particle size P2. Separation can for example take effect in such a particle separator 20 only at or above a particle size of 60 m or 70 m, while a separation efficiency of 90% is achieved at a particle size of P4, where P4<100 m, for example at P4=90 m.

(35) Configuring the particle separator 20 in accordance with the separation curve A20 is particularly favourable with a view to protecting the assigned phase adjuster 10 or assigned system of phase adjusters 10 as effectively as possible on the one hand, and operating without the need for maintenance and for as long a service life as possible on the other. In the case of a particle separator 20 exhibiting the separation curve A20, a measurable separation of dirt particles takes effect immediately at or above the particle size P2. The separation curve A20 does not overlap with the separation curve A3 of the main oil separator 3, or not measurably in standard test procedures, but does begin directly at or at least near to the particle size P2 at which the main oil separator 3 achieves a separation efficiency of at least 90% or more preferably almost 100%. The particle separator 20 achieves a separation efficiency of 90% at a particle size P4 of less than 100 m and a separation efficiency of almost 100% for particles of a mean particle size P5>P4. The particle size P4 at which the particle separator 20 exhibits a separation efficiency of 90% is advantageously less than 90 m and can in particular be less than 80 m. Using the separation curve A20, the particle separator 20 already achieves a separation efficiency of almost 100%, such as for example 97%, for particles of the particle size P5 which is smaller than the mean particle size P4 of a particle separator 20 which is coarser in accordance with the separation curve A20 but still in accordance with the invention. A separation efficiency of 50% is achieved in all three cases only at a particle size P3, where P3>P2. For reasons of space, the particle sizes of the .sub.3,50 separation efficiencies are not indicated for the separation curves A20 and A20.

(36) The particle separator 20 is particularly suitable for keeping original dirt, still present in the lubricating oil cycle from the production of the internal combustion engine, away from the one or more phase adjusters 10. Original dirt is formed for example by sand and corundum particles still left over from die-casting parts of the engine block and/or from blast-treating parts of the engine in the region of the conduits which guide lubricating oil. During the running-in period of the engine, original dirt can reach the one or more phase adjusters 10 if it were not effectively separated by the one or more particle separators 20. Original dirt can also in principle become detached even after longer periods of operation and, if a particle separator 20 is not provided, can reach the one or more phase adjusters 10 before it is separated in the main oil separator 3. Dirt particles of a potentially damaging particle size can also above all enter the lubricating oil cycle during cold start phases of the internal combustion engine, specifically when the bypass valve 3a is open and the lubricating oil pump 1 therefore delivers the lubricating oil to the lubricating oil gallery 5 by bypassing the main oil separator 3. Other causes for the introduction of comparatively large dirt particles include repair work on components of the internal combustion engine which come into contact with the lubricating oil, and also changing the main oil separator 3, as is routinely done once the service life envisaged for the main oil separator 3 has been reached. Conversely, since the particle separator or separators 20 achieve a separation efficiency of 50% (.sub.3,50) only at a mean particle size P3, which is larger than the particle size P1 and preferably larger than the particle size P2 for the 90% (.sub.3,90) separation efficiency of the main oil separator 3, this counters the danger of the particle separator 20 becoming blocked.

(37) As shown by the separation curve AFP indicated for comparison purposes in the diagram of FIG. 4, the filter screens hitherto used for phase adjusters, which are respectively arranged in the phase adjuster, only achieve separation efficiencies of 50%, 90% and almost 100% for dirt particles having particle sizes between P6 and P7 which are significantly above 100 m and typically even above 200 m. The particle separating system of the invention can comprise a particle separator in the respective phase adjuster 10, although this is not required since the particle separator 20, which is advantageously arranged near or preferably immediately on the phase adjuster 10, ensures more effective particle separation.

(38) FIG. 5 shows a phase adjuster 10 and a particle separator 20 which is assigned to said phase adjuster 10 only, such as are shown schematically in FIGS. 1 and 2. The phase adjuster 10 comprises a stator 11, which is driven by a crankshaft of the internal combustion engine in a fixed rotational speed relationship to the crankshaft, and a rotor 12 which is non-rotationally connected to a cam shaft 6. The stator 11 surrounds the rotor 12 over its outer circumference. The stator 11 and the rotor 12 can be rotated about the rotational axis R of the cam shaft 6, wherein the rotor 12 can be moved back and forth within a predetermined rotational angular range relative to the stator 11 in a leading direction and in a trailing direction counter to the leading direction, in order to be able to adjust the rotational angular position of the cam shaft 6 relative to the crankshaft.

(39) The phase adjuster 10 is embodied as a vane motor. Correspondingly, one or more vanes protrude/s radially inwards from the inner circumference of the stator 11, while one or more vanes project radially outwards from the outer circumference of the rotor 12, such that a pressure chamber into which the lubricating oil can be introduced as a pressure medium is respectively formed between a vane of the stator 11 and a vane of the rotor 12 which is adjacent in the circumferential direction. At least two such pressure chambers are formed in the phase adjuster 10, namely one pressure chamber for adjusting the rotor in one rotational direction and another pressure chamber for adjusting in the other rotational direction, such that the rotor 12 can be selectively adjusted to either lead or trail relative to the stator 11. The stator 11 and the rotor 12 can in particular each comprise multiple vanes which co-operate in this way, such that multiple pressure chambers for adjusting in the leading direction and multiple pressure chambers for adjusting in the trailing direction are formed between the stator 11 and the rotor 12 in a distribution about the rotational axis R.

(40) The phase adjuster 10 comprises a control valve featuring a valve housing 13 and a valve piston 14 which can be moved back and forth in the valve housing 13 between control positions. A spring force is applied to the valve piston 14 by a valve spring 15 in one direction in which it can be moved, and the valve piston 14 can be moved in the opposite direction, counter to the elastic restoring force of the valve spring 15, by means of an electromagnetic device 16.

(41) The control valve comprises a pressure port P, a working port A, a working port B and at least one tank port Tin the example embodiment, two tank ports T. The control valve adjoins the lubricating oil cycle at the pressure port P, such that pressurised lubricating oil can flow through the pressure port P into the control valve and thus into the phase adjuster 10. One of the working ports A and B is connected to the pressure chamber or chambers for adjusting the rotor 12 in the leading direction, and the other of the working ports A and B is connected to the pressure chamber or chambers for adjusting the rotor 12 in the trailing direction. Depending on the control position of the valve piston 14, the pressure port P is connected to either the working port A or the working port B, such that the pressurised lubricating oil flows via the relevant working port A or B into the assigned pressure chamber(s) and the rotor 12 is adjusted relative to the stator 11 in the corresponding rotational direction. The other of the working ports A and B is simultaneously connected to one of the tank ports T, such that the lubricating oil can flow off via said other working port A or B and the assigned tank port T to the lubricating oil reservoir S (FIG. 1) and the assigned pressure chamber(s) is/are relieved of pressure.

(42) The control valve is embodied as a so-called central valve, i.e. it protrudes centrally in the axial direction into the rotor 12. The valve housing 13 simultaneously serves to non-rotationally connect the rotor 12 to the cam shaft 6. In order to perform this function, it protrudes through the rotor 12 towards a fitting end of the cam shaft 6 and is fixedly connected to the cam shaft 6, for example screwed or pressed onto the cam shaft 6, in the region of the fitting end.

(43) A reflux valve is arranged between the pressure port P and the working ports A and B in the valve housing 13. The reflux valve comprises a blocking member 17, a blocking member spring 18 and a support structure 19. The blocking member 17 can in particular be a sphere. The blocking member spring 18 acts on the blocking member 17 in the direction of a blocking position in which it seals the pressure port P, such that lubricating oil is prevented from flowing back towards the particle separator 20. When a certain minimum pressure is reached, the blocking member 17 is lifted off its seating, such that lubricating oil can flow into the control valve and, depending on the control position of the valve piston 14, via either the working port A or the working port B into the respectively assigned pressure chamber(s). The opposite end of the blocking member spring 18 to the blocking member 17 is supported on the support structure 19. The support structure 19 is held in the valve housing 13 in a positive fit by means of a locking connection.

(44) Other details of the design and also other details of the functionality of the phase adjuster 10 are described in EP 2 578 818 B1 and also in U.S. Pat. No. 9,021,997 B2, which are each incorporated by reference. Reference is made to these documents with regard to advantageous embodiments of the phase adjuster 10.

(45) The particle separator 20 is arranged upstream of the phase adjuster 10 and completely outside the phase adjuster 10, albeit in the immediate vicinity of the phase adjuster 10, specifically directly on the pressure port P of the phase adjuster 10. The particle separator 20 is arranged in a hollow space 7 of the cam shaft 6. The lubricating oil is correspondingly fed to the phase adjuster 10 through the cam shaft 6, specifically through the hollow space 7. More precisely, the hollow space 7 is formed in the end portion of the cam shaft 6 to which the phase adjuster 10 is fastened by means of the valve housing 13. This enables the particle separator 20 to be arranged as near as possible to the phase adjuster 10.

(46) FIG. 6 shows the end portion of the cam shaft 6 which is used for fitting the phase adjuster 10, together with the particle separator 20 arranged in it, in an enlarged representation.

(47) The particle separator 20 comprises an upstream first separating stage 21 and a second separating stage 22 which is downstream in relation to the flow direction of the lubricating oil, wherein the lubricating oil flows through the separating stages one after the other before it can enter the control valve and thus the phase adjuster 10 through the pressure port P. The first separating stage 21 is a centrifugal force separator in which dirt particles contained in the lubricating oil are separated due to centrifugal force. The second separating stage 22 is formed as a filter structure comprising a filter medium 23 for the lubricating oil. The lubricating oil has to flow through the filter medium 23 on its way to the phase adjuster 10.

(48) The lubricating oil flows into the hollow space 7 via an inlet 8. When the internal combustion engine is in operation, the cam shaft 6 rotates about the rotational axis R which is simultaneously also a central longitudinal axis of the hollow space 7. The lubricating oil is set in rotational motion about the rotational axis R in the hollow space 7 due to the rotational movement of the cam shaft 6. In order to amplify the rotational movement, the inlet 8 is embodied such that the lubricating oil flows into the hollow space 7 with a directional component which is tangential to the rotational axis R, wherein the inflow direction points in the rotational direction of the cam shaft 6. An annular gap can be formed between the cam shaft 6 and a body, for example a bearing body, which surrounds the cam shaft 6, wherein one or more inlet channels exhibiting a tangential directional component lead/s inwards from the annular gap up to one or more inlet openings which feed/s into the hollow space 7. Immediately upstream of the annular channel, a non-rotating oil feed channel can already feed, tangentially to the rotational axis R, into the annular channel, wherein this upstream feed channel expediently feeds into the annular channel in the rotational direction of the cam shaft 6. The lubricating oil thus obtains a rotational impulse even as it flows into the annular channel, is swept along by the rotating cam shaft 6 in the annular channel and is guided into the hollow space 7, likewise with a tangential directional component, in the inlet region of the cam shaft 6 between the annular channel and the inlet openings.

(49) A deflecting structure 26 which is arranged upstream of the first separating stage 21 in the hollow space 7 deflects the lubricating oil again with a directional component which points tangentially to the rotational axis R, in the same direction as the rotational direction of the cam shaft 6, thus further increasing the rotational velocity of the lubricating oil flow in the hollow space 7. The rotational velocity of the lubricating oil flow immediately after it flows into the hollow space 7 or through the deflecting structure 26 is advantageously greater than the rotational velocity of the cam shaft 6, such that the lubricating oil flow is faster than the cam shaft 6 in the rotational direction.

(50) FIG. 7 shows the cross-section A-A from FIG. 6, i.e. it shows in particular the deflecting structure 26. The deflecting structure 26 comprises multiple plate-shaped, fin-shaped or bowl-shaped deflecting elements in a distribution about the rotational axis R, between which the lubricating oil can flow through the deflecting structure 26 in the axial direction, wherein it is deflected in the tangential direction. The deflecting elements, which are likewise denoted by 26 in FIG. 7, are arranged on and protrude radially inwards from a fitting ring 26a which is used for fastening in the hollow space 7.

(51) As already mentioned, the first separating stage 21 is a centrifugal force separator. It comprises a sleeve-shaped absorbing medium which lines an inner circumferential wall of the hollow space downstream of the deflecting structure 26. Dirt particles are pressed outwards towards and into the absorbing medium of the centrifugal force separator 21 due to the centrifugal force acting on the lubricating oil. The absorbing medium is formed such that it traps the absorbed dirt particles at or above a certain particle size.

(52) FIG. 8 shows among other things the filter structure 22, arranged downstream of the centrifugal force separator 21, in the cross-section B-B from FIG. 6. The filter structure 22 comprises a filter medium 23 which the lubricating oil can flow through, and a support structure 24 (FIGS. 6 and 7) which supports the filter medium 23 and is simultaneously also used for fitting the filter structure 22. The filter medium 23 is pleated, i.e. placed in folds around the circumference of the rotational axis R, in order to obtain as large a filter surface as possible. The filter medium 23 surrounds an axially elongated interior space of the filter which remains clear of filter material and through which the cleaned lubricating oil can flow off in the axial direction directly to the pressure port P. The support structure 24 forms an end region of the filter structure 22 which axially faces the pressure port P and an end region of the filter structure 22 which faces away from the pressure port P. The end region which faces the pressure port P comprises a filter outlet 25 as a central passage for the lubricating oil. The filter outlet 25 is in axial alignment with the pressure port P, such that the cleaned lubricating oil can flow off with very little resistance.

(53) As can be seen in FIGS. 6 to 8, the two separating stages 21 and 22, i.e. the centrifugal force separator 21 and the filter structure 22, are arranged concentrically with respect to each other with the rotational axis R as a central filter axis. The filter medium 23 of the filter structure 22 protrudes axially into the centrifugal force separator 21; in the example embodiment, the filter medium 23 protrudes through the centrifugal force separator 21. In order for fluid to still flow through the separating stages 21 and 22 sequentially, a sleeve-shaped flow channelling structure 27 is arranged in the hollow space 7, wherein a side of the flow channelling structure 27 which faces the inlet 8 comprises a closed base, i.e. one which the lubricating oil cannot flow through, and the flow channelling structure 27 protrudes axially from said base into an annular hollow space volume 9 between the centrifugal force separator 21 and the filter structure 22 and, as is preferred but merely by way of example, as far as the vicinity of the downstream end of the centrifugal force separator 21.

(54) The flow channelling structure 27 delineates the deflecting structure 26 radially inwards. As a result, the lubricating oil which flows through the inlet 8 into the hollow space is forced radially outwards by the flow channelling structure 27, such that it has to flow through the deflecting structure 26. Once it has flowed through the deflecting structure 26, the lubricating oil flows axiallyand with a rotational movement superimposed on its axial movementthrough an outer annular space which is delineated on the radially outer side by the centrifugal force separator 21 and on the radially inner side by the flow channelling structure 27, is deflected radially inwards towards the filter medium 23 at the end of the flow channelling structure 27, and due to its delivery pressure is distributed uniformly over the outer surface of the filter medium 23 in an inner annular space which remains clear between the flow channelling structure 27 and the filter medium 23. If the phase adjuster 10 takes up lubricating oil, the lubricating oil which has been pre-cleaned by means of the centrifugal force separator 21 flows around the filter medium 23 in an axial and tangential direction, in order to ultimately flow through the filter medium 23 into the hollow interior space of the filter and from there to the filter outlet 25 and through the filter outlet 25 into and through the pressure port P of the phase adjuster 10.

(55) The absorbing medium of the centrifugal force separator 21 can in particular contain or consist of fibrous material. Fleece materials are particularly suitable. The absorbing medium can instead also be a fabric material or a mesh or can contain a fabric material and/or mesh, for example in addition to fleece material. Open-pored foam material is likewise a suitable absorbing medium and can form the absorbing medium of the centrifugal force separator 21 instead of the other absorbing media mentioned or in combination with one or more of these other absorbing media. The absorbing medium can be single-ply or multi-ply and can for example comprise one or more layers of fleece and one or more layers of fabric in a radially layered arrangement. It can be formed as a graded medium, such that it exhibits a porosity which is comparatively high at its inner circumference pointing towards the filter structure 22 but decreases radially outwards. In other modifications, the centrifugal force separator 21 can comprise a sleeve-shaped perforated shutter. A perforated sleeve structure can exhibit a slightly smaller outer diameter than the hollow space 7, such that an absorbing space for the dirt particles separated in the centrifugal force separator 21 remains, radially behind such a perforated screen-like structure as viewed from the rotational axis R. Fleece material and/or fabric material and/or mesh material and/or an open-pored foam material can be arranged in the absorbing space in order to even more securely trap the separated dirt particles.

(56) The absorbing medium can consist of or contain plastic, glass or paper, for example plastic fibres and/or glass fibres and/or a plastic fabric and/or open-pored sponge made of plastic. Alternatively or additionally, the absorbing medium can contain a metal material, for example metal fibres and/or metal particles and/or a metal fabric material and/or metal fleece and/or open-pored metal foam. Combinations of a plastic material and a metal material are also possible. If a magnetic metal material is used, the absorbing medium can also separate ferritic particles irrespective of their particle size.

(57) The statements made with respect to the material of the absorbing medium also apply in the same way to the material of the filter medium 23.

(58) FIG. 9 shows an alternative embodiment of the centrifugal force separator 21, in a cross-section through the cam shaft 6, wherein this can be the same cross-sectional plane as in FIG. 8. The centrifugal force separator 28 in FIG. 9 can substitute for the centrifugal force separator in FIG. 8. The centrifugal force separator 28 comprises a multitude of scoops in a distribution about the rotational axis R, wherein the scoops protrude from a circumferential wall of the hollow space 7 radially inwards and substantially in the tangential direction, such that pockets 29 are formed between the circumferential wall and the scoops for absorbing dirt particles forced outwards by the centrifugal force. The absorbing pockets 29 open in the rotational direction of the cam shaft 6. In addition to absorbing dirt particles, the scoops also perform a function of rotationally slaving the lubricating oil. Rotational slaving is however also improved relative to a smooth circumferential wall of the hollow space by the absorbing medium of the centrifugal force separator 21. The centrifugal force separator 28 in FIG. 9 also comprises a fitting ring 29a which is used for fitting and from which the scoops protrude radially inwards and in the tangential direction.

(59) FIG. 10 shows the support structure 19 of the reflux valve which is arranged in the control valve (FIG. 5). The support structure 19 comprises a support disc, which the lubricating oil can flow through, at one axial end and holding arms which project axially from support disc and radially outwards. The support structure 19 is formed such that it offers as little resistance as possible to the lubricating oil flowing through the pressure port P into the control valve. The ends of the holding arms which face axially away from the support disc comprises holding elements which project outwards and via which the support structure 19 grips behind a collar provided in the valve housing 13, in order to be able to absorb the force of the blocking member spring 18.

(60) FIG. 11 shows a particle separator 30 in a second example embodiment. The particle separator 30 is likewise arranged immediately upstream of the phase adjuster 10. The phase adjuster 10 can correspond completely to the phase adjuster 10 of the first example embodiment or, as can be seen in FIG. 11 and described below, can deviate from it in some details. Wherever the phase adjuster 10 assigned to the particle separator 30 is not described in more detail, it corresponds in any event to the phase adjuster 10 of the first example embodiment.

(61) The particle separator 30 likewise comprises a first separating stage 31 and a second separating stage 32 which the lubricating oil flows through one after the other, i.e. sequentially, on its way to the phase adjuster 10. The upstream first separating stage is formed as a centrifugal force separator 31, as in the first example embodiment. The downstream second separating stage is likewise formed as a filter structure 32 as in the first example embodiment. The separating stages 31 and 32 are however arranged successively or at least substantially successively not only in relation to the flow direction of the lubricating oil but also in the axial direction. The centrifugal force separator 31 is arranged entirely within the hollow space 37 of the cam shaft 6 and comprises an absorbing medium which is arranged on the inner circumference of the cam shaft 6. With regard to the absorbing medium of the centrifugal force separator 31, the statements made with respect to the first example embodiment apply in the same way. The absorbing medium can in particular be a fibrous material which lines an axial portion of the circumferential wall of the hollow space 37. The alternative absorbing media described can alternatively or additionally also be realised.

(62) As likewise in the first example embodiment, the filter structure 32 comprises a filter medium 33, which the lubricating oil can flow through, and a support structure 34 which supports the filter medium 33 and is used for fitting the filter structure 32 directly on the pressure port P. As in the first example embodiment, the filter medium 33 is pleated by being placed in folds around the circumference of the rotational axis R. Once it has flowed through the centrifugal force separator 31, the lubricating oil reaches the filter structure 32, flows around its outer circumference axially but with a superimposed rotational movement, i.e. spirally, flows through the filter medium 33 and flows in the axial direction in the unimpeded central interior space of the filter to the pressure port P which is in axial alignment with the interior space of the filter, as in the first example embodiment.

(63) As long as the phase adjuster 10 does not take up any lubricating oil, at least the centrifugal force separator 31 is effective, wherein as the dwelling time increases, a higher proportion of the dirt particles contained in the lubricating oil are centrifuged into the absorbing medium of the centrifugal force separator 31. Arranging the centrifugal force separator 31 in a tube portion of the cam shaft 6 enables the centrifugal force separator 31 to be realised with a large axial length of the absorbing medium which is advantageous for extracting dirt particles by centrifuging. The greater the axial length of the centrifugal force separator 31, the higher the capacity for absorbing dirt particles, all other installation conditions being equal, and the longer the dwelling time of the lubricating oil in the portion of the hollow space 37 which is surrounded by the centrifugal force separator 31. This applies equally to the centrifugal force separator 21 of the first example embodiment and in principle also to a centrifugal force separator arranged on a rotary body other than the cam shaft 6. Arranging it in the cam shaft 6 does however have the advantage that, like the centrifugal force separator 21 of the first example embodiment, the centrifugal force separator 31 can be realised on the flow path of the lubricating oil near to the phase adjuster 10, thus countering a subsequent introduction of dirt particles into the cleaned lubricating oil.

(64) Unlike the first example embodiment, the filter structure 32 is not formed substantially within the centrifugal force separator 31. As can be seen in FIG. 11, there can be a minor axial overlap between the centrifugal force separator 31 and the filter structure 32, but a majority of the axial length of the filter structure 32 protrudes beyond the centrifugal force separator 31 in the direction of the phase adjuster 10. The disadvantage of an axial length which is greater than in the first example embodiment is matched by the advantage that design space is gained for the filter structure 32 and thus for the filter medium 33 in the radial direction and that the filter medium 33 can have a larger radial width than the filter medium 23 of the first example embodiment when the diameter of the hollow space 37 formed in the cam shaft 6 corresponds to the diameter of the hollow space 7 of the first example embodiment.

(65) In the second example embodiment, design space is also gained in the radial direction by a part of the filter structure 32 protruding axially out of the cam shaft 6 and into a radially broadened hollow space of a hollow body 36. The hollow body 36 is used for fitting the phase adjuster 10 on the end portion of the cam shaft 6. It is pressed or screwed onto the outer circumference of the cam shaft 6 or otherwise non-rotationally connected to the cam shaft 6 in order to obtain a radially widened end portion 39 of the hollow space 37. The hollow body 36 extends the hollow end portion of the cam shaft 6 and widens its hollow space 37 into the radially wider hollow space 39, such that design space for the control valvethe valve housing 13, blocking member 17 and blocking member spring 18 of which can be seenand the filter structure 32 is created in accordance with the larger diameter of the hollow space 39. The rotor 12 of the phase adjuster 10 is non-rotationally connected to the hollow body 36 by means of the valve housing 13 and is non-rotationally connected via the hollow body 36 to the cam shaft 6.

(66) In order to make the best possible use of the design space, the filter structure 32 and in particular its filter medium 33 exhibits the shape of a truncated cone, wherein the tapered end protrudes into the hollow space 37 of the cam shaft 6 and the radially wider end protrudes into the hollow space 39 of the hollow body 36. To assist this, the cam shaft 6 can be widened at its axially outer end, as can be seen in FIG. 11, in order to widen the hollow space 37 even there. The filter structure 32 is held on the valve housing 13 by means of a locking connection, wherein the locking connection is between the support structure 34 and a radial appendage of the valve housing 13 which is formed on the pressure port P. The filter outlet 35 and the pressure port P are in axial alignment with each other, as in the first example embodiment. The support structure 34 comprises thin, radially projecting arms 34a for centring it in the hollow space 37, 39. The arms 34a can also serve to axially support the filter structure 32 in order to keep the filter structure 32 axially in position even if the locking connection to the valve housing 13 is released.

(67) FIG. 12 shows the inlet into the hollow space 37 of the cam shaft 6, in the cross-section A-A from FIG. 11. The tangential feed 38a can be seen which has already been described on the basis of the first example embodiment and which is formed in a body which is stationary when the engine is in operation, for example a bearing body for the cam shaft 6. The feed 38a feeds into an annular gap 38b, formed between the cam shaft 6 and said body, and flows from the annular gap 38b into the hollow space 37 via inlet channels 38c which lead through the cam shaft 6. The inlet channels 38c likewise point with a tangential directional component with respect to the rotational axis R. Thus, in the second example embodiment, the rotational impulse of the lubricating oil flow again increases not only because of the rotational movement of the cam shaft 6 but also because of the doubly tangential feed. The feed 38a and the inlet channels 38c expediently point in the rotational direction of the cam shaft 6.

(68) FIG. 13 shows the cross-section B-B from FIG. 11. The pleated filter medium 33 and the central interior space of the filter, and also the arms 34a of the support structure 34, can in particular be seen.

(69) FIGS. 14 and 15 show a particle separator 40 of a third example embodiment: in FIG. 14, in a central longitudinal section; and in FIG. 15, in the cross-section A-A from FIG. 14. The particle separator 40 is a cyclone separator. It is formed in a pressure storage via which the phase adjuster 10 is supplied with the lubricating oil as a pressure medium. Cam shaft phase adjusters comprising a pressure storage are described in U.S. Pat. No. 8,061,317 B2, and U.S. Pat. No. 9,200,546 B2, which are each incorporated by reference, to name but two examples.

(70) The pressure storage and/or cyclone separator 40 comprises a housing featuring a housing part 41 and a cover 42 which closes off the housing part 41 axially opposite a base of the housing part 41. A piston 43 is accommodated in the housing 41, 42, such that it can be moved axially back and forth. A spring force is applied to the piston 43 in the direction of the cover 42 by a spring 44. The cyclone separator 40 is arranged upstream of the phase adjuster 10 in the lubricating oil feed to the phase adjuster 10, such that lubricating oil can only reach the phase adjuster 10 through the cyclone separator 40.

(71) The lubricating oil flows through the inlet 48 into a cyclone space 47 which is delineated in the cyclone separator 40 by the housing part 41, the cover 42 and the piston 43. The inlet 48 is embodied such that the lubricating oil in the cyclone space 47 performs a rotational movement about a central cyclone axis. As the pressure at the inlet 48 increases, the rotational movement is amplified. As can be seen in FIG. 15, the inlet 48 comprises a feed channel which points tangentially to the central longitudinal axis of the cyclone separator 40the central cyclone axis Zand which also feeds tangentially into the cyclone space 47, such that the said vortex flow is created in the cyclone space 47. The lubricating oil in the cyclone space 47 acts on the piston 43 and moves it, counter to the spring force of the spring 44, in the direction of enlarging the cyclone space 47.

(72) The cyclone space 47 comprises an axial cylindrical vortex portion 47a which is axially delineated by the cover 42 and by the front side of the piston 43 which faces the cover 42. The vortex portion 47a is adjoined by an axially orientated funnel portion 47b in which the cyclone space 47 is gradually constricted. The constricted end of the funnel portion 47b feeds into a separating portion 47c. An absorbing medium 46 for dirt particles to be separated is arranged in the separating portion 47c. The separating portion 47c can in particular be axially cylindrical, as can be seen in FIG. 14. The absorbing medium 46 lines the circumferential wall of the separating portion 47c, such that dirt particles are pressed into and trapped in the absorbing medium 46 due to the centrifugal force. The lubricating oil into and trapped in the absorbing medium 46 due to the centrifugal force. The lubricating oil from which the separated dirt particles have been removed flows off towards the pressure port P of the phase adjuster 10 via an outlet 49.

(73) The absorbing medium 46 can in particular be formed so as to correspond to the absorbing medium of the first example embodiment, i.e. it can for example comprise one or more layers of a fibrous material and/or one or more layers of fabric and/or can be a graded medium.

(74) The outlet 49 extends through the cover 42. The outlet 49, which leads out of the cover 42 in parallel with the cyclone axis Z, is extended into the cyclone space 47 so that the lubricating oil flowing in laterally cannot immediately flow off via the outlet 49. The extension is formed by an immersion support 45 in the manner of immersion tubes such as are known in cyclone separators. The immersion support 45, however, protrudes by only a short axial distance into the cyclone space 47. The length by which the immersion support 45 can protrude into the cyclone space 47 is limited by the piston 43.

(75) The inlet 48 is formed on a circumferential wall of the cyclone space 47in the example embodiment, on a circumferential wall of the housing part 41. The outlet 49, by contrast, axially extends centrally along the cyclone axis Z through the cover 42. The immersion support 45 extends axially into the cyclone space 47 and expediently overlaps the inlet 48 over all of its height as measured in parallel with the cyclone axis Z, in order to screen the outlet 49 against the inlet 48.

(76) The piston 43 forms the funnel portion 47b and also the separating portion 47c so that the pressure storage and/or cyclone separator 40 can be designed to be axially short. If the delivery pressure of the lubricating oil falls below a value which is determined by the spring 44, the spring 44 pushes the piston 43 axially towards the cover 42 until it abuts against it. In the abutting position, the axial length of the vortex portion 47a is at a minimum. The immersion support 45 can protrude into the funnel portion 47b when the piston 43 assumes its abutting position. The piston 43 should not however seal the inlet 48 in its abutting position.

(77) The cyclone separator 40 can substitute for the particle separator 20 or more preferably for the centrifugal force separator 21 of the first example embodiment only. In other embodiments, the cyclone separator 40 can however also be provided in addition to the particle separator 20 of the first example embodiment and can be arranged upstream of the particle separator 20 in such embodiments. If the cyclone separator 40 substitutes for the centrifugal force separator 21 only, a filter structure comprising a filter medium, preferably a pleated filter medium, is again arranged downstream of the cyclone separator 40, as for example in the first example embodiment or in the second example embodiment. The cyclone separator 40 can also be arranged upstream of the particle separator 30 of the second example embodiment, in order to feed lubricating oil which has already been pre-cleaned to the centrifugal force separator 31. In another modification, it can substitute for the centrifugal force separator 31.

(78) FIG. 16 shows a particle separator 50 of a fourth example embodiment. The particle separator 50 is formed in a co-operation between the cam shaft 6 and a non-rotatable body 56. The cam shaft 6 extends axially through the body 56. The body 56 can in particular be a bearing body for the cam shaft 6.

(79) The cam shaft 6 and the body 56 together form a hollow space 57 which is delineated on the radially inner side by the cam shaft 6 and on the radially outer side by the body 56. An inlet 58 feeds into the hollow space 57, wherein lubricating oil flows into the hollow space 57 through the inlet 58. The inlet 58 can be embodied as described with respect to the first example embodiment or can be embodied like the feed 38a of the second example embodiment (FIG. 12), in order to immediately imbue the lubricating oil with a rotational impulse in the rotational direction of the cam shaft 6 even as it flows in. In the hollow space 57, the rotating cam shaft 6 imbues the lubricating oil with an additional rotational impulse. The rotational impulse can be amplified even more by non-rotationally connecting a slaving structure 54 to the cam shaft 6. The slaving structure 54 can comprise projections and for example form a vane wheel in order to impose a tangential acceleration and/or radial acceleration on the lubricating oil as it flows around or through it. The slaving structure 54 is arranged in an axial portion of the hollow space 57 in which the hollow space 57 is radially widened, in order to form a centrifugal force separator 51. The widening is denoted by 52. Downstream of the slaving structure 54 and the widening 52, the hollow space 57 is constricted to form an annular gap 55 through which the lubricating oil flows in the axial direction. The annular gap 55 connects the hollow space 57 to an outlet 59 of the particle separator 50. Once it has flowed through the particle separator 50, the lubricating oil flows through the outlet 59 of the particle separator 50 into a hollow space 7 which, as in the first and second example embodiments, is formed in an end portion of the cam shaft 6 on which the phase adjuster 10 is fitted. The lubricating oil thus reaches the pressure port P of the phase adjuster 10 through the outlet 59 and the hollow space 7.

(80) The particle separator 50 is formed in the manner of a dosing bearing. The annular gap 55 downstream of the centrifugal force separator 51 prevents lubricating oil laden with dirt particles from simply flowing through the hollow space 57. The slaving structure 54 likewise acts in this sense. The trapped dirt particles are above all centrifuged by the centrifugal force into the radial widening 52, where they are trapped. The rotational movement of the cam shaft 6 relative to the body 56 prevents the annular gap 55 from becoming blocked.

(81) An absorbing medium for absorbing and trapping dirt particles can be arranged in the widening 52. With regard to the optional absorbing medium, the statements which have already been made with respect to the centrifugal force separator 21 of the first example embodiment apply. The absorbing medium can in particular contain or consist of fibrous material or a fabric material, to name but two examples. Alternatively, however, absorbing pockets can also be formed in the widening 52 which for example correspond to the absorbing pockets 29 from FIG. 9.

(82) In the example embodiment, the slaving structure 54 is non-rotationally connected to the cam shaft 6. In one modification, a deflecting structure which is fixedly connected to the body 56 can be provided instead of the slaving structure 54 and can comprise deflecting elements in a distribution about the rotational axis R which correspond to the deflecting structure 26 of the first example embodiment (FIGS. 6 and 7), in order to deflect the lubricating oil with a tangential directional component with respect to the rotational axis R and so amplify the rotational movement and the effect of the centrifugal force.

(83) As in the other example embodiments, the particle separator 50 performs its separating function in multiple separating stages. The centrifugal force separator 51 forms the first separating stage. Downstream of the centrifugal force separator 51, the particle separator 50 comprises a second separating stage 62 which, as in the first and second example embodiments, is a filter structure 62 comprising a filter medium 63 and a support structure 64 for the filter medium 63. The lubricating oil which is pre-cleaned in the centrifugal force separator 51 has to flow through the filter medium 63 in order to reach the pressure port P of the phase adjuster 10.

(84) In relation to its filter properties, the filter structure 62 corresponds to the filter structures 22 and 32 of the previous example embodiments. As in the first and second example embodiments, the filter medium 63 is pleated, i.e. it is placed in folds around the filter axis which coincides with the rotational axis R. The filter medium 63 can as such correspond to the filter media 23 and 33 of the first and second example embodiments.

(85) The end portion of the hollow space 7 which faces the phase adjuster 10 widens radially, thus producing a widened hollow space 67 and therefore design space for the valve housing 13 of the control valve and also for the filter structure 62. The filter structure 62 is accommodated in the radially widened end portion of the hollow space 7. It is axially supported in one direction on a facing end face of the valve housing 13 and in the opposite direction on a collar of the cam shaft 6.

(86) The hollow space 67 in which the filter structure 62 is arranged comprises an inlet 68 which exhibits a tangential directional component in relation to the rotational axis R which also forms the central longitudinal axis of the hollow space 67 and a central filter axis. The lubricating oil which flows from the outlet 59 of the hollow space 57 into the inlet 68 thus obtains a tangential directional component with respect to the rotational axis R as it flows through the inlet 68. The lubricating oil therefore flows through the hollow space 67 with a tangential directional component when the phase adjuster 10 takes up lubricating oil. The lubricating oil also correspondingly flows around the filter structure 62. The lubricating oil therefore not only flows through the filter medium 63 in the radial direction but also flows around the filter medium 63 in the circumferential direction and in the axial direction. This generates transverse flow filtration.

(87) One particularity of the phase adjuster 10 is that if the rotor 12 is adjusted relative to the stator 11, the one or more pressure chambers which are relieved of pressure when adjusting is performed are not relieved through the control valve into the outer environment of the phase adjuster 10. The lubricating oil of the pressure-relieved pressure chamber(s) is drained from the respective working port A or B into the hollow space of the valve housing 13 or into a hollow space formed in the valve piston 14 and from the relevant hollow space through the tank port T of the valve housing 13. In the example embodiment, the lubricating oil flows through the tank port T into the hollow cam shaft 6, specifically into its hollow space 7, whence it flows off towards the lubricating oil sump S (FIG. 1).

(88) The pressure port P and the tank port T are provided at the same axial end of the valve housing 13 and each extend up to an axial end face of the valve housing 13. The tank port T extends up to and into the hollow space of the valve housing 13. The hollow space of the valve piston 14 axially faces the tank port T. Thus, depending on the position which the valve piston 14 assumes in the valve housing 13, either the working port B is connected to the tank port T through the hollow space of the valve housing 13 by bypassing the valve piston 14, or the working port A is instead connected to the tank port T by the central hollow space of the valve piston 14. The hollow space of the valve piston 14 opens into the hollow space of the valve housing 13, axially facing the tank port T.

(89) When the pressure is relieved, the lubricating oil is drained from both the working port A and the working port B through the tank port T.

(90) The tank port T is formed as an axial passage in the valve housing 13. The tank port T connects the hollow space of the valve housing 13, in which the valve piston 14 is arranged such that it can be moved back and forth, and also the hollow space of the valve piston 14 to the hollow space 7 of the cam shaft 6.

(91) Unlike the first and second example embodiments, the filter structure 62 comprises a central tubular outflow portion 69 through which the lubricating oil flows off from the phase adjuster 10. The outflow portion 69 is arranged on the tank port T of the control valve, in axial alignment with it. The lubricating oil can thus flow off with little resistance through the tank port T, which extends axially in the valve housing 13, and through the outflow portion 69 which adjoins it in axial alignment. From the outflow portion 69, the lubricating oil which is flowing off enters the hollow space 7 of the cam shaft 6 and flows off through the hollow space 7 towards the lubricating oil sump S (FIG. 1).

(92) The phase adjuster 10 of the fifth example embodiment is driven via a belt drive in a fixed rotational speed relationship to the crankshaft. The stator 11 is non-rotationally connected to a belt output wheel 71 of the belt drive. In the example embodiment, the belt output wheel 71 is moulded in an original-moulding process in one piece with a middle part of the stator 11 which is joined together from multiple parts. The belt output wheel 71 surrounds the actual stator 11 over its outer circumference.

(93) The belt drive is realised as a dry-running belt drive. The lubricating oil flowing off from the phase adjuster 10 is therefore not drained via a tank port T (FIG. 5) connected to the outer environment of the phase adjuster 10, as in the first and second example embodiments, but rather through the hollow valve housing 13 within the phase adjuster 10 via the axial tank port T already mentioned and, in an axial extension of the tank port T, through the outflow portion 69. The phase adjuster 10, i.e. the components of the phase adjuster 10 which come into contact with the lubricating oil, is therefore sealed off from the environment and thus from the belt drive. It is sealed off axially on both sides of the array consisting of the stator 11 and the rotor 12, by means of a shaft sealing ring 75 on the side facing the cam shaft 6 and a shaft sealing ring 76 on the side facing the electromagnetic device 16. A radial shaft sealing ring serves as each of the sealing ring 75 and 76.

(94) The hydraulic region of the phase adjuster 10 is sealed off from the body 56 by means of the shaft sealing ring 75. The hydraulic part of the phase adjuster 10 is sealed off from a housing 16a of the electromagnetic device 16 by means of the shaft sealing ring 76. The housing 16a and the body 56 cannot be moved relative to each other. They are fixedly connected to an engine housing of the internal combustion engine in a way which is not shown. The body 56 can in particular be a cast region of the engine housing. The housing 16a can be fitted, stationary relative to the engine housing, on the engine housing or a different structure which is connected to it. The belt can thus revolve dry, i.e. with no lubricating oil which flows off from the phase adjuster 10, in a hollow space of the engine housing.

(95) The filter structure 62 comprises a filter outlet 65, axially facing the valve housing 13, which extends around the outflow portion 69. The phase adjuster 10 comprises a pressure port P featuring multiple pressure port channels which are arranged in a distribution about the rotational axis R and feed to the end face of the valve housing 13, axially opposite the filter outlet 65, and which each extend through the valve housing 13 from where they feed to the end face, pointing obliquely outwards, to the rotational axis R. Lubricating oil which flows obliquely outwards through the filter outlet 65 to the pressure port P and through the pressure port channels is channeled in one or more connecting channels 72 on the outer circumference of the valve housing 13 into one or more pressure channels 73 which extends or which each extend radially through the valve housing 13 towards the valve piston 14. Depending on the control position which the valve piston 14 assumes, the pressure port P is connected to either the working port A or the working port B via 72 and 73.

(96) In FIG. 16, the valve piston 14 has assumed a control position in which the pressure port P is connected to the working port A. In this control position, the working port B is connected to the hollow space formed in the valve housing 13 and, via said hollow space, to the tank port T and the outflow portion 69 of the filter structure 62. The lubricating oil which is cleaned by means of the particle separator 50 thus flows through the pressure port P and the working port A into the pressure chamber(s) assigned to the working port A, while the lubricating oil from the pressure chamber(s) assigned to the working port B flows off via the tank port T and the outflow portion 69. If the valve piston 14 is switched by means of the electromagnetic device 16, i.e. moved into the other control position against the force of the valve spring 15, the connection between the pressure channel(s) 73 and the working port A is interrupted, and the pressure channel(s) 73 is/are instead connected to the working port B. The working port A is simultaneously connected to the hollow space of the valve housing 13 via one or more passages 74 formed in the valve piston 14, such that the lubricating oil can flow off from the working port A through the tank port T and the outflow portion 69.

(97) The filter structure 62 therefore performs a dual function. In its primary function, it serves to clean the lubricating oil to be fed to the phase adjuster 10. In its secondary function, it serves to drain the lubricating oil which the phase adjuster 10 consumes in the performance of its setting function.

(98) It may also be stated with respect to the geometry of the filter structure 62 that the filter medium 63 extends around the tubular outflow portion 69. An annular interior space of the filter which remains between the filter medium 63 and the outflow portion 69 comprises the filter outlet 65 at an end axially facing the control valve, in particular the pressure port P. The filter medium 63 widens towards the pressure port P.

(99) The electromagnetic device 16 is connected to an engine controller for the internal combustion engine and receives control signals from the engine controller, on the basis of which it determines the control position of the valve piston 14 in co-operation with the valve spring 15. The electromagnetic device 16 comprises an electromagnetically operable actuator 78 which is in an axial pressing contact with the valve piston 14 and which, when current is passed through a coil of the electromagnetic device 16, moves the valve piston 14 into the other control position against the force of the valve spring 15. The abutting and/or pressing contact between the valve piston 14 and the actuator 78 is punctiform. For this purpose, the end of the actuator 78 facing the valve piston 14 can be curved spherically or otherwise bulbously towards the valve piston 14, as shown in FIG. 5 for the first example embodiment. In the fifth example embodiment, the valve piston 14 comprises an end 77 which is spherical or otherwise bulbous towards the actuator 78, axially facing the actuator 78, while the end of the actuator 78 which faces the valve piston 14 is substantially planar. The bulge on the valve piston side has the advantage that the point of contact between the valve piston 14 and the actuator 78 does not drift if the valve piston 14 and the actuator 78 are not exactly in axial alignment with each other when installed.

(100) The filter media 23, 33 and 63 of the example embodiments and the filter medium of a filter structure of the particle separator in accordance with the invention in general can be single-ply or multi-ply. They can in particular comprise one or more layers of a fibrous material and/or one or more layers of a fabric material and/or one or more layers of a mesh. They can be formed as graded media. When formed as graded media, they are coarser on the respective inflow side than on the outflow side. The inflow side can in particular be formed by the outer circumference of the respective filter medium, as in the example embodiments.

(101) The absorbing media of the centrifugal force separators and/or the filter media of the filter structures of the particle separator in accordance with the invention can contain or consist of magnetised metal material, in order to trap ferritic particles irrespective of their particle size. Ferritic particles are damaging in particular to electromagnetic actuators of phase adjusters. Magnetised metal material can for example also be arranged in the widening 52 of the centrifugal force separator 51 of the fourth example embodiment. The particle separator can comprise a ferrite separator featuring magnetised metal material, i.e. a separating stage for ferritic particles, in addition to the separating stages described and in particular upstream of the first separating stage. Additionally or alternatively, a separating stage for ferritic particles can be provided between the first separating stage and the second separating stage in the flow direction of the lubricating oil.

(102) FIG. 17 shows a phase adjuster 10 comprising a particle separator 80 of a fifth example embodiment. The particle separator 80 consists of a centrifugal force separator 81 which is formed in hollow spaces 87 of the stator 11. In further developments, the particle separator 80 can comprise one or more additional separating stages, for example a separating stage arranged upstream of the centrifugal force separator 81 and/or a separating stage arranged downstream of the centrifugal force separator 81. The centrifugal force separator 51 comprising the annular gap 55 of the fourth example embodiment can then for example be connected upstream of the centrifugal force separator 81 and/or a filter structure comprising a filter medium which fluid can flow through can then for example be connected downstream of the centrifugal force separator 81.

(103) The lubricating oil is fed to the phase adjuster 10 through one or more feed channels 88 and one or more inlet channels 8 connected to them, at a pressure port P of the phase adjuster 10. The feed channel(s) 88 is/are formed in a bearing body 86 which mounts the cam shaft 6. The feed channel(s) 88 is/are adjoined by the one or more inlet channels 8 which extend/s in the end portion of the cam shaft 6 and feed/s into the pressure port P. Multiple feed channels 82a in a distribution around the rotational axis R extend radial outwards from the pressure port P. The feed channels 82a are each connected to the particle separator 80 via an inlet 83a.

(104) FIG. 18 shows the phase adjuster 10 of the fifth example embodiment in a cross-section. Only an outer circumferential region of the phase adjuster 10, in which the particle separator 80 is situated, is shown. It can also be seen in the cross-section that the phase adjuster 10 is embodied as a vane motor.

(105) The particle separator 80 comprises multiple hollow spaces 87 which extend around the rotational axis R near the outer circumference of the stator 11. The hollow spaces 87 each extend over an angular segment only, i.e. they are hollow space angular segments. The hollow spaces 87 sub-divide the stator 11 into an outer stator ring and an inner region of the stator comprising vanes which protrude radially inwards. The stator ring and the inner region of the stator are connected via support structures which extend in the radial direction between adjacent hollow spaces 87.

(106) In the example embodiment, the hollow spaces 87 are separated from each other. They are next to each other and level in the circumferential direction, wherein one of the support structures extends between each two adjacent hollow spaces 87. The outer stator ring, the inner region of the stator and the connecting support structures can be moulded in one piece in an original-moulding method, in particular by die-casting or pressing and sintering. In modifications, however, the hollow spaces 87 can also be connected to each other in the circumferential direction and form a contiguous hollow space 87 which encircles the rotational axis R through 360. In such embodiments, support structures would no longer extend over the whole of the axial length of the hollow spaces 87 which are separated from each other in the example embodiment, but rather only then over some of the axial length. In another modification, support structures in the middle can be omitted if the outer stator ring and the inner region of the stator are fixedly connected to each other, forming a seal, on each of the end faces. In such modifications, the outer stator ring, the inner region of the stator and the connecting structures on the end face would be produced separately from each other and joined together to form the stator.

(107) The lubricating oil flows through the hollow spaces 87 in the axial direction. It is fed to the respective hollow space 87 through a respectively assigned inlet 83a on one end face and flows off through an assigned outlet 83b on the other, axially opposite end face and a continuative drainage channel 82b adjoining the outlet 83b. In the drainage channels 82b, the lubricating oil flows back towards the rotational axis R and enters the hollow space of the valve housing 13 via one or more pressure channels 84. The pressure channel(s) 84 form/s the pressure port of the control valve.

(108) In FIG. 17, the valve piston 14 has assumed a control position in which the pressure port P is connected to the control port A via the centrifugal force separator 81 and the pressure channel(s) 84. The control port B is connected to the tank port T of the control valve through the hollow space of the valve housing 13 and is relieved of pressure via the tank port T and continuative channels. If the valve piston 14 is switched to the other control position by means of the electromagnetic device 16, the working port B is connected to the pressure channel(s) 84, while the working port A is connected to the tank port T via one or more passages 85 formed in the valve piston 14, such that the pressure chambers assigned to the working port A are relieved of pressure.

(109) An inlet 83a and an outlet 83b feed into each of the hollow spaces 87, such that the lubricating oil flows in the rotational direction of the stator 11 from the respective inlet 83a to the respective outlet 83b. If the phase adjuster 10 takes up lubricating oil, the lubricating oil in the hollow spaces 87 is therefore not only rotated at the rotational velocity of the stator 11 but rather also exhibits an additional velocity which points in the rotational direction.

(110) The surface of the outer circumferential wall in the hollow spaces 87 can be structured, as can be seen by way of example in FIG. 18, in order to trap particles centrifuged outwards by the centrifugal force more securely than with a smooth circumferential wall in the respective hollow space 87. In principle, however, the outer circumferential walls of the hollow spaces 87 can also be smooth, since the dirt particles adhere to each other when extracted by centrifuging, and a sort of slurry or cake of dirt particles is gradually formed even on a comparatively smooth circumferential wall. The stator 11 can for example be provided with a structured surface in the hollow space(s) 87 directly as it is original-moulded.

(111) In an advantageous development, an absorbing medium of the type described, for example fibrous material, can be arranged on the outer circumferential wall of the respective hollow space 87, in order to improve the trapping properties of the centrifugal force separator 81.

(112) FIG. 19 shows an outer structure 82 and an inner structure 83 which jointly form the pressure port P, the feed channels 82a which lead radially outwards from the pressure port P to the centrifugal force separator 81, and the inlets 83a. The structures 82 and 83 are planar structures which, when the phase adjuster 10 is assembled, are joined to a middle part of the stator 11 and axially abut each other such that they cannot be rotated and close off, on the end face, the pressure chambers formed between the stator 11 and the rotor 12. Another such array consisting of an outer structure 82 and an inner structure 83 is provided on the other end face of the stator 11 and non-rotationally connected to the middle part in the same way, in order to close off the pressure chambers on the other end face and to form the outlets 83b and the continuative drainage channels 82b (FIG. 17). The feed channels 82a are formed by fillet indentations in the outer structure 82. The inner structure 83 can simply be formed as a planar disc, as in the example embodiment, in order to seal the drainage channels 82b inwards, towards the pressure chambers, in a simple design. The continuative drainage channels 82b and outlets 83b out of the hollow space annular segments 87 are formed in the same way on the other end face by the structures 82 and 83 on that end face.

(113) The phase adjuster 10 is driven by means of a belt drive, as in the fourth example embodiment. The outer circumference of the stator 11 is provided with a toothed gearing for a toothed engagement with the drive belt. The belt is a dry-running belt, as in the fourth example embodiment. The phase adjuster 10 is correspondingly sealed off on both its end face facing the cam shaft 6 and its opposite end face, on which the electromagnetic device 16 is arranged, by means of a radial shaft sealing ring 89 in each case.

REFERENCE SIGNS

(114) 1 lubricating oil pump

(115) 2 cooler

(116) 3 main oil separator

(117) 3a bypass valve

(118) 4 secondary flow oil separator

(119) 5 lubricating oil gallery

(120) 5.sub.i lubricating oil consumption points

(121) 6 cam shaft

(122) 7 hollow space

(123) 8 inlet, inlet channel

(124) 9 hollow space volume

(125) 10 cam shaft phase adjuster

(126) 11 stator

(127) 12 rotor

(128) 13 valve housing

(129) 14 valve piston

(130) 15 valve spring

(131) 16 electromagnetic device

(132) 16a housing

(133) 17 blocking member

(134) 18 blocking member spring

(135) 19 support structure

(136) 20 particle separator

(137) 21 centrifugal force separator, absorbing medium

(138) 22 filter structure

(139) 23 filter medium

(140) 24 support structure

(141) 25 filter outlet

(142) 26 deflecting structure

(143) 26a fitting ring

(144) 27 flow channelling structure

(145) 28 centrifugal force separator

(146) 29 absorbing pockets

(147) 29a fitting ring

(148) 30 particle separator

(149) 31 centrifugal force separator, absorbing medium

(150) 32 filter structure

(151) 33 filter medium

(152) 34 support structure

(153) 34a arm

(154) 35 filter outlet

(155) 36 hollow body

(156) 37 hollow space

(157) 38 inlet

(158) 38a feed

(159) 38b annular channel

(160) 38c inlet channel

(161) 39 hollow space

(162) 40 particle separator, cyclone separator

(163) 41 housing part

(164) 42 cover

(165) 43 piston

(166) 44 spring

(167) 45 immersion support

(168) 46 absorbing medium

(169) 47 cyclone space

(170) 47a vortex portion

(171) 47b funnel portion

(172) 47c separating portion

(173) 48 inlet

(174) 49 outlet

(175) 50 particle separator

(176) 51 centrifugal force separator

(177) 52 widening

(178) 53

(179) 54 deflecting or slaving structure

(180) 55 annular gap

(181) 56 body

(182) 57 hollow space

(183) 58 inlet

(184) 59 outlet

(185) 60

(186) 61

(187) 62 filter structure

(188) 63 filter medium

(189) 64 support structure

(190) 65 filter outlet

(191) 66

(192) 67 hollow space

(193) 68 inlet

(194) 69 outflow portion

(195) 70

(196) 71 belt output wheel

(197) 72 connecting channel

(198) 73 pressure channel

(199) 74 passage

(200) 75 shaft sealing ring

(201) 76 shaft sealing ring

(202) 77 valve piston end

(203) 78 actuator

(204) 79

(205) 80 particle separator

(206) 81 centrifugal force separator

(207) 82 outer structure

(208) 82a feed channel

(209) 82b drainage channel

(210) 83 inner structure

(211) 83a inlet

(212) 83b outlet

(213) 84 pressure channel, pressure port

(214) 85 passage

(215) 86 body

(216) 87 hollow space

(217) 88 feed channel

(218) 89 shaft sealing ring

(219) A working port

(220) B working port

(221) P pressure port

(222) R rotational axis, longitudinal axis

(223) S lubricating oil reservoir

(224) T tank port

(225) Z cyclone axis