CAMSHAFT ADJUSTING DEVICE

Abstract

A camshaft adjusting device, wherein said camshaft adjusting device has a lubricant supply unit, wherein the lubricant supply unit has a filter device for filtering the lubricant, wherein the filter device has at least one lubricant inlet, at least one lubricant outlet and at least one filter path, wherein the lubricant inlet and the lubricant outlet are fluidically connected to each other by way of the filter path, and wherein an output shaft of the camshaft adjusting device has two wall sections, wherein the at least one filter path is configured in a filter volume between the two wall sections, and wherein the lubricant inlet is at a smaller distance from the axis of rotation than the lubricant outlet, and the filter path extends at least in sections in the radial direction with respect to the axis of rotation.

Claims

1-10. (canceled)

11. Camshaft adjusting device comprising: a variator arranged on an axis of rotation for adjusting an angular position of a camshaft, the variator comprising: an input shaft selectively coupled to a crankshaft; an output shaft selectively coupled to the camshaft; and, an adjusting shaft selectively coupled to an actuator; an internal gear space formed by the variator, wherein the input shaft, the output shaft and the adjusting shaft are operatively connected to each other in the internal gear space; a lubricant supply unit for supplying the internal gear space with a lubricant, the lubricant supply unit comprising: a filter device for filtering the lubricant, the filter device comprising: at least one lubricant inlet; at least one lubricant outlet; and, at least one filter path, the filter path fluidically connecting the lubricant inlet and the lubricant outlet; wherein, the output shaft comprises two wall sections and the at least one filter path is configured in a filter volume between the two wall sections.

12. The camshaft adjusting device as recited in claim 11, wherein the lubricant inlet is at an equal or smaller distance from the axis of rotation than the lubricant outlet, and the filter path extends radially outward from the axis of rotation.

13. The camshaft adjusting device as recited in claim 11, wherein structural elements are disposed in the filter volume and integrally connected to the wall sections and/or are formed by an insert part.

14. The camshaft adjusting device as recited in claim 13, wherein the structural elements form one or more flow obstacles, so that the at least one filter path extends around the flow obstacles.

15. The camshaft adjusting device as recited in claim 13, wherein the structural elements form one or more dirt pockets, wherein the dirt pockets are open radially inward with respect to the axis of rotation.

16. The camshaft adjusting device as recited in claim 13, wherein the structural elements are designed at least partially in the manner of islands.

17. The camshaft adjusting device as recited in claim 13, wherein the percentage of the area of the structural elements, which make contact with the two wall sections, forms at least 50% of the total area of the filter device.

18. The camshaft adjusting device as recited in claim 11, wherein the at least one filter path is formed as a flat channel and extends in the form of a spiral and/or in a labyrinthine manner between the at least one lubricant inlet and the at least one lubricant outlet.

19. The camshaft adjusting device as recited in claim 18, wherein the at least one filter path is guided, starting from the lubricant inlet, to an outer region, which is at a greater radial distance from the axis of rotation than the lubricant outlet and subsequently is guided in the form of a spiral and/or in a labyrinthine manner to the lubricant outlet in a return region.

20. The camshaft adjusting device as recited in claim 11, wherein the at least one filter path is formed as an annular disk and/or as an annular disk segment, wherein preferably an outlet pocket is provided, wherein the outlet pocket is open radially outward.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0035] Various embodiments are disclosed, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, in which:

[0036] FIG. 1 is a schematic overview of a camshaft adjusting device as an exemplary embodiment of the invention;

[0037] FIG. 2 is a cross-sectional view of the variator of the camshaft adjusting device in FIG. 1;

[0038] FIG. 3a, b is a schematic three-dimensional representation of the camshaft adapter with or without the end cap, as shown in FIG. 2; and,

[0039] FIGS. 4, 5 are in each case a schematic plan view of the camshaft adapter as another exemplary embodiment of the invention.

DETAILED DESCRIPTION

[0040] At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements. It is to be understood that the claims are not limited to the disclosed aspects.

[0041] Furthermore, it is understood that this disclosure is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the claims.

[0042] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure pertains. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the example embodiments.

[0043] It should be appreciated that the term substantially is synonymous with terms such as nearly, very nearly, about, approximately, around, bordering on, close to, essentially, in the neighborhood of, in the vicinity of, etc., and such terms may be used interchangeably as appearing in the specification and claims. It should be appreciated that the term proximate is synonymous with terms such as nearby, close, adjacent, neighboring, immediate, adjoining, etc., and such terms may be used interchangeably as appearing in the specification and claims. The term approximately is intended to mean values within ten percent of the specified value.

[0044] FIG. 1 is a schematic representation of camshaft adjusting device 1 for an engine, in particular, an internal combustion engine of a vehicle, as a first exemplary embodiment of the invention. Camshaft adjusting device 1 comprises camshaft 2, which has a plurality of cams 3, which are designed to actuate the valves of the engine.

[0045] The drive of camshaft 2 is provided by way of drive gear 4, which is coupled to a crankshaft (not shown) of the engine by means of a chain, a belt or a transmission. Variator 5 is interposed between drive gear 4 and camshaft 2. Variator 5 allows an angular adjustment of camshaft 2 to be effected in a controlled fashion relative to drive gear 4 and, as a result, relative to the crankshaft (not shown). In order to control variator 5, this variator is coupled to electric motor 6 by means of motor shaft 13, which is arranged so as to be stationary relative to variator 5. That is, motor shaft 13 does not rotate along with variator 5.

[0046] Camshaft adjusting device 1 comprises lubricant supply unit 7, which introduces, starting from an oil pan or, more specifically, oil tank 8, transmission oil as a lubricant into camshaft 2 through motor oil pump 9 by means of a rotary transmitter (not shown) for oil. The lubricant is fed from camshaft 2 through lubricant feed line 11 into variator 5, in order to lubricate variator 5 and is then discharged again from variator 5 through lubricant discharge line 12, so that lubricant supply unit 7 is designed as a lubricant circuit. FIG. 2 is a cross-sectional view of variator 5 taken along axis of rotation D, which is defined, for example, by camshaft 2 or motor shaft 13 (FIG. 1).

[0047] Variator 5 is also designed as a so-called wave gear (also called a harmonic drive gear). Wave gear 5 is also referred to as a sliding wedge gear, or a strain wave gear (SWG). Variator 5 has input shaft 14, which is coupled in a rotationally fixed manner to drive gear 4 or is formed by this drive gear. Furthermore, variator 5 has output shaft 15, which is connected to camshaft 2 in a rotationally fixed manner. In contrast, adjusting shaft 16 is connected to motor shaft 13 in a rotationally fixed manner. Adjusting shaft 16 has generator section 17, which has a cross-section that is perpendicular to axis of rotation D and which is designed so as to be not round, in particular to be elliptical. Rolling bearing 18 is disposed on said generator section in such a way that inner ring 19 of rolling bearing 18 rests on a shell surface of generator section 17; and outer ring 20 bears a deformable, cylindrical steel bushing 21 with external gear teeth. Steel bushing 21 is also referred to as a flex spline. Steel bushing 21 is designed with a cross-section, which is perpendicular to axis of rotation D, and is designed to be elliptical as well.

[0048] Input shaft 14 bears internal gear teeth 22, which mesh with the external gear teeth of steel bushing 21. Output shaft 15 bears internal gear teeth 23, which also mesh with the external gear teeth of steel bushing 21. By rotating adjusting shaft 16 at an angular velocity that is different from the angular velocity of input shaft 14, it is possible to adjust input shaft 14 and output shaft 15 in terms of the angular position to each other. Such a harmonic drive gear is also described, for example, in the publication DE 10 2005 018 956 A1. Input shaft 14, output shaft 15 and adjusting shaft 16 come into operative connection in interaction region 28 by means of internal gear teeth 22, 23 and external gear teeth of steel bushing 21. In addition, variator 5 has sliding bearing section 24 between a carrier of internal gear teeth 23 of output shaft 15 and input shaft 14.

[0049] Variator 5 forms internal gear space 25, which is formed by input shaft 14, on the one hand, by means of supporting member 26 and, on the other hand, by means of cover 27, where in this case rolling bearing 18 and interaction region 28 of the external gear teeth of steel bushing 21 and internal gear teeth 22 and 23 are disposed in internal gear space 25 of sliding bearing section 24.

[0050] Output shaft 15 is divided into camshaft adapter 29, which is connected in a rotationally fixed manner to camshaft 2, and end cap 30, which is designed as a circular ring member and is also connected in a rotationally fixed manner to camshaft adapter 29. Ring gear section 31 is connected by choice, as shown in the figure, in a rotationally fixed manner to end cap 30 or is formed in one piece with said end cap. Ring gear section 31 bears internal gear teeth 23.

[0051] Filter device 32 is integrated into output shaft 15. This filter device is supplied with lubricant by camshaft 2 by means of lubricant feed line 11 and exactly or at least one lubricant inlet 33, which is disposed in output shaft 15, in particular in camshaft adapter 29. Lubricant inlet 33 is designed, for example, as an axially extending lubricant channel that has a first distance from axis of rotation D. As an alternative to the positioning of lubricant inlet 33 in camshaft adapter 29, lubricant inlet 33 may also be disposed radially inwards in a receiving region for camshaft 2, where in this case the alternative position of lubricant inlet 33 is indicated by dashed lines.

[0052] Filter device 32 includes lubricant outlet 34, which is also designed in this example as an axially extending lubricant channel, wherein the lubricant channel is spaced apart at a second distance from axis of rotation D, wherein the second distance is designed to be larger than the first distance. Lubricant outlet 34 is integrated into end cap 30 and is open in the direction of inner gear space 25. Filter device 32 comprises filter volume 35, which is arranged, when viewed fluidically, between lubricant inlet 33 and lubricant outlet 34. Filter volume 35 is formed by means of two wall sections 36a and 36b, where in this case wall section 36a is formed by means of an axially oriented end face of end cap 30, and second wall section 36b by means of an axially oriented end face of camshaft adapter 29. Wall sections 36a and 36b extend in a radial plane, which is arranged perpendicular to axis of rotation D. As a result, filter volume 35 is located at the interface between camshaft adapter 29 and end cap 30. Lubricant inlet 33, filter volume 35 and lubricant outlet 34 jointly define exactly or at least one filter path 37, which extends at least in sections in the radial direction with respect to axis of rotation D. This configuration ensures that the length of filter path 37 is artificially lengthened, so that the filtering action of filter device 32 is improved. Filter volume 35 is closed radially at each end, i.e., radially inwards and radially outwards, due to the fact that camshaft adapter 29 and end cap 30 lie one on top of the other in a sealing manner. In particular, filter volume 35 is formed in each instance by means of a recessed region in camshaft adapter 29 and in end cap 30. Instead of providing in each of said components a recessed area, it is also possible to arrange by choice a recess only on the side of camshaft adapter 29 or only on the side of end cap 30, so that filter volume 35 is arranged asymmetrically, especially on one side, with respect to the plane of separation between camshaft adapter 29 and end cap 30.

[0053] In FIGS. 3a and 3b output shaft 15 is shown in a schematic three-dimensional sectional view. In FIG. 3b camshaft adapter 29 is shown in an individual representation. Camshaft adapter 29 is designed as an annular component, which is arranged coaxially to axis of rotation D. Camshaft adapter 29 has a central receiving opening 38 for an end section of camshaft 2 and can be connected, for example, to end cap 30 in a rotationally fixed manner by means of pin 39. End cap 30 is designed as a circular ring component, which has radially collar 40 on the inner circumference, with said collar being arranged coaxially to receiving opening 38. By inserting collar 40 into receiving opening 38, end cap 30 and camshaft adapter 29 are centered with respect to each other. The connection between the two components can be carried out, for example, by means of a screw connection (not shown). Ring gear section 31 is mounted radially externally on end cap 30 with internal gear teeth 23.

[0054] As can be seen in FIG. 3b, lubricant can flow through receiving opening 38 between collar 40 and camshaft adapter 29 to filter device 32, so that the overlapping region between collar 40 and receiving opening 38 forms lubricant inlet 33. Starting from radially inner lubricant inlet 33, lubricant is then fed along filter path 37, which extends in an unbranched manner, into outer region 41, which is located radially outside of lubricant inlet 33 and also lubricant outlet 34. Starting from outer region 41, the lubricant is then initially fed in a first concentric track and is subsequently fed in a labyrinthine manner to a second concentric track, where in this case the second concentric track has a smaller pitch circle diameter than the first concentric track. Furthermore, the flow direction of the lubricant changes with respect to the circumferential direction to axis of rotation D. In particular, filter path 37 has at least one reversal of rotation of the lubricant with respect to axis of rotation D and/or folding. Lubricant outlet 34 is arranged at the end of the second concentric track. The folding of filter path 37 ensures that filter path 37 is artificially extended.

[0055] Structural elements 42 are arranged along filter path 37. Such structural elements form dirt pockets 43, which are arranged at the edge along filter path 37 and which are open in the radial direction inward with respect to axis of rotation D. When camshaft adjusting device 1 is running, dirt pockets 43 are filled with lubricating oil. Due to the fact that output shaft 15 rotates together with camshaft 2, the lubricant is conveyed from radially inner lubricant inlet 33 by means of centrifugal force in the direction of filter path 37. At the same time the dirt particles are pushed into dirt pockets 43 due to centrifugal force and can no longer leave also due to centrifugal force, so that the dirt particles are trapped. In addition, switching from the first concentric track to the second concentric track also ensures that only the easily flowing lubricant, but not the dirt particles, can be moved onto the second concentric path, so that it must be assumed that the filtering action is very good.

[0056] Filter path 37 is designed as a recess in camshaft adapter 29; in contrast, structural elements 42 are unrecessed regions in the region of filter device 32. Even the walls between the first and the second concentric track are formed by means of continuous structural elements 42. Camshaft adapter 29 implements second wall section 36b with this design. In contrast, first wall section 36a is designed as a flat region on the side of end cap 30 and seals off the walls of second wall section 36b, so that the lubricant can run exclusively along filter path 37. The way along filter path 37 is designed as a flat channel, which has more or less a constant depth in the axial direction in this example.

[0057] Since filter path 37 extends in a labyrinthine manner due to the structural elements 42, the way between the lubricant inlet 33 and lubricant outlet 34 is extended by at least a factor of 5, preferably by at least a factor of 10. Thus, the concept of filter device 32 provides that the lubricant, coming from lubricant inlet 33, is first fed radially directly or through loops outwards. The infeed of the lubricant through lubricant outlet 34 into internal gear space 25 is effected on an inner radius.

[0058] Described in general terms, one or more concentrically arranged annular grooves can be provided as the tracks, where in this case the innermost of the annular grooves is fluidically connected to lubricant outlet 34; and the outermost of the annular grooves is fluidically connected to lubricant inlet 33.

[0059] As an alternative, filter path 37 may be guided in the form of a spiral, where in this case the infeed on the smallest radius is guided by way of a spiral to the largest radius. As an alternative, even in the case of the spiral-shaped course lubricant inlet 33 can be initially connected to an outer section of the spiral, and lubricant outlet 34 can be connected to a radially inner section of the spiral. Another alternative would be a plurality of ray-shaped channels that radiate from one or more lubricant inlets 33 and that open into dirt pockets 43.

[0060] Dirt pockets 43 lie outside the lubricant flow. Since filter path 37 has a channel cross-section that is enlarged because of dirt pockets 43, the flow velocity is reduced, so that the dirt particles can be separated by means of the centrifugal force even at low rotational speeds of camshaft 2. Due to the pocket shape of dirt pockets 43, so-called shallow regions are formed, and these shallow regions prevent the dirt particles from being entrained again by the lubricant flow.

[0061] Aside from the aforementioned radial expansion of the flow cross-section along filter path 37 due to dirt pockets 43, these dirt pockets may also be expanded in the axial direction, i.e., in the depth.

[0062] Additional microstructures on the walls of the channels, in the demolding direction during production, can generate turbulence in order to reduce the flow rate and to improve the process for separating out the dirt particles and the suspended particles.

[0063] FIG. 4 shows an example embodiment of camshaft adapter 29, where in this case structural elements 42 are arranged and designed in filter device 32 in such a way that these structural elements form free-standing dirt pockets 44. The free-standing dirt pockets 44 are open towards axis of rotation D. In this example embodiment the lubricant, which is fed through radially inner lubricant inlet 33, is guided past free-standing dirt pockets 44 along one or more filter paths 37, which together form a filter path network. In this case it is provided that the dirt particles are trapped again in free-standing dirt pockets 44. Filter device 32 extends in the form of an annular disk by 360 degrees around axis of rotation D.

[0064] Structural elements 42 may also form flow obstacles 45, as shown in FIG. 5. Owing to the distribution, in particular, owing to an opening width O between flow obstacles 45, filter device 32 may be designed as a classical screen, where in this case the mesh size of the screen is defined by opening width O. Such reduced cross-sections along filter path 37 make it possible to screen large dirt particles out of the lubricant. Free-standing dirt pockets 44, which can be distributed in the screen surfaces, can absorb the dirt particles and, in so doing, can direct said dirt particles away from the lubricant flow. In addition, the free-standing dirt pockets prevent the free cross-sections of the openings from clogging over the runtime; and the volumetric rate of flow of the lubricant is throttled.

[0065] Several parallel extending channel sections ensure that the volumetric rate of flow is not substantially throttled in total. In parallel, however, the function of a throttling operation across the width and depth of the channels along filter path 37 can be integrated at the same time.

[0066] Additional microstructures on the walls of the channels, in the demolding direction during production, are supposed to generate turbulence in order to improve the process for separating out the dirt particles and the suspended particles.

[0067] It is possible to generate different screen planes by staggering opening cross-sections O of the channels of filter paths 37. This being the case, opening widths O are gradually tapered or reduced in size outwards in the radial direction, so that initially larger and later also smaller dirt particles can be sieved out.

[0068] FIG. 5 also shows outlet pocket 46, which, in contrast to dirt pockets 43, 44, is open radially outwards, so that only the lubricant, which comes from radially outside and is, therefore, already freed of dirt particles, enters into outlet pocket 46. One of lubricant outlets 34 is arranged in outlet pocket 46. The circumferential boundary of filter volume 35 forms an annular channel as a collector and as an outlet for the lubricant and is fluidically connected to lubricant outlet 34.

[0069] It will be appreciated that various aspects of the disclosure above and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

LIST OF REFERENCE CHARACTERS

[0070] 1 camshaft adjusting device [0071] 2 camshaft [0072] 3 cams [0073] 4 drive gear [0074] 5 variator [0075] 6 electric motor [0076] 7 lubricant supply unit [0077] 8 oil tank [0078] 9 motor oil pump [0079] 10 empty [0080] 11 lubricant feed line [0081] 12 lubricant discharge line [0082] 13 motor shaft [0083] 14 input shaft [0084] 15 output shaft [0085] 16 adjusting shaft [0086] 17 generator section [0087] 18 rolling bearing [0088] 19 inner ring [0089] 20 outer ring [0090] 21 steel bushing [0091] 22 internal gear teeth [0092] 23 internal gear teeth [0093] 24 sliding bearing section [0094] 25 internal gear space [0095] 26 supporting member [0096] 27 cover [0097] 28 interaction region [0098] 29 camshaft adapter [0099] 30 end cap [0100] 31 ring gear section [0101] 32 filter device [0102] 33 lubricant inlet [0103] 34 lubricant outlet [0104] 35 filter volume [0105] 36a, b wall sections [0106] 37 filter path [0107] 38 receiving opening [0108] 39 pin [0109] 40 collar [0110] 41 outer region [0111] 42 structural elements [0112] 43 dirt pockets [0113] 44 free-standing dirt pockets [0114] 45 flow obstacles [0115] 46 outlet pocket [0116] D axis of rotation [0117] O opening width