Pump comprising a spring

Abstract

A pump, wherein a first pressure space and a second pressure space are formed between an end-facing wall of an accommodating housing and a second housing part of a pump insert, wherein an annular sealing element which is arranged between the end-facing wall and the second housing part encloses the second pressure space and seals it off in relation to the first pressure space, wherein the first pressure space is connected via a first outlet channel to a first delivery chamber which is formed between a rotor and a stroke ring of the pump insert, and the second pressure space is connected via a second outlet channel to a second delivery chamber which is formed between the rotor and the stroke ring.

Claims

1. A pump, comprising: an accommodating housing having an end-facing wall and a circumferential wall, whereby a cup-shaped accommodating space is formed; and a pump insert which is arranged in the cup-shaped accommodating space, wherein the pump insert comprises: a rotor; a first housing part and a second housing part, between which the rotor is rotatable about a rotational axis and relative to the first and second housing parts; and a stroke ring which surrounds the rotor, wherein a first pressure space and a second pressure space are formed between the end-facing wall and the second housing part, wherein an annular sealing element which is arranged between the end-facing wall and the second housing part encloses the second pressure space and seals it off in relation to the first pressure space, wherein a first seal is arranged between the pump insert and the accommodating housing, and a second seal is arranged between the second housing part and the circumferential wall of the accommodating housing, the second seal seals off the first pressure space in relation to a suction space, and the suction space is arranged between the first seal and the second seal, wherein the first pressure space is connected via a first outlet channel to a first delivery chamber which is formed between the rotor and the stroke ring, and the second pressure space is connected via a second outlet channel to a second delivery chamber which is formed between the rotor and the stroke ring.

2. The pump according to claim 1, wherein the suction space is formed between the circumferential wall and the pump insert, wherein the pump is adapted to deliver fluid from the suction space via the first delivery chamber to the first pressure space, and via the second delivery chamber to the second pressure space.

3. The pump according to claim 1, wherein the first seal is arranged between the first housing part and the circumferential wall of the accommodating housing.

4. The pump according to claim 1, wherein the first housing part is secured to the accommodating housing, and at least the second housing part and the stroke ring are held between the end-facing wall of the accommodating housing and the first housing part.

5. The pump according to claim 4, wherein a spring which flexes along or in the direction of the rotational axis is arranged between the end-facing wall and the second housing part, wherein the spring comprises a spring structure which is made of metal and which imbues the spring with its essential spring characteristics along or in the direction of the rotational axis, and wherein the spring is supported towards the second housing part and thus presses the second housing part against the stroke ring.

6. The pump according to claim 5, wherein the spring is arranged in the first pressure space.

7. The pump according to claim 5, wherein the spring comprises at least one fastening element, wherein the spring is fastened to the second housing part or to at least one positioning element protruding from the second housing part, by the at least one fastening element.

8. The pump according to claim 5, wherein the spring structure is made from steel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention has been described on the basis of a number of examples and embodiments, and in particular aspects. The developments of one aspect can also develop the other aspects, without however necessarily having to utilise the central concept of the other aspect. Particularly preferred embodiments of the invention are described on the basis of figures. The features thus disclosed, individually and in any combination of features, advantageously develop the subject-matter of the invention. There is shown:

(2) FIG. 1 a detail of a sectional representation through a rotational axis of a rotor, wherein a pump insert is shown inserted into an accommodating housing;

(3) FIG. 2 a sectional view of the pump insert from FIG. 1, through the rotational axis;

(4) FIG. 3 a perspective view of the pump insert from FIG. 2;

(5) FIGS. 4 and 5 embodiments of a spring for the pump assembly;

(6) FIG. 6 another embodiment of a spring for the pump assembly;

(7) FIG. 7 an embodiment of a spring for the pump assembly, exhibiting an O-ring-shaped cross-section;

(8) FIG. 8 an embodiment of a spring for the pump assembly, exhibiting a C-ring-shaped cross-section;

(9) FIG. 9 an embodiment of a seal which is arranged between the pump assembly and the accommodating housing;

(10) FIG. 10 another embodiment of a seal;

(11) FIG. 11 yet another embodiment of a seal;

(12) FIG. 12 yet another embodiment of a seal;

(13) FIG. 13 yet another embodiment of a seal;

(14) FIG. 14 yet another embodiment of a seal;

(15) FIG. 15 yet another embodiment of a seal;

(16) FIG. 16 yet another embodiment of a seal;

(17) FIG. 17 a pump insert, in a section along the rotational axis of the rotor, wherein the pump insert comprises a spring which is combined with a seal;

(18) FIG. 18 a perspective view of the pump insert from FIG. 17;

(19) FIG. 19 representations of the spring which is combined with the seal; and

(20) FIG. 20 an example of a cross-section through a pump insert, in the region of the rotor.

(21) FIGS. 2, 3, 17 and 18 show pump inserts which can be inserted into an accommodating housing, as shown in FIG. 1. The pump, in particular the pump insert 1, comprises a spring 5 which is shown here in various embodiments. The pump or pump insert 1 can comprise a seal 9, in particular an axial seal, which is arranged between an end-facing wall 20c of an accommodating housing 20 and a second housing part 3. The seal 9 is shown in various embodiments, in some of which it is combined with the spring 5.

DETAILED DESCRIPTION OF THE INVENTION

(22) The pump or pump insert 1 comprises a rotor 4 which is non-rotationally connected to a pump shaft 10 via a shaft-hub connection 30. The rotor 4 comprises cavities which serve as a guide and are in particular slot-shaped. A delivery element 13, in particular a vane, is assigned to each cavity. The vane 13 can be shifted radially back and forth in its cavity, away from and towards the rotational axis R of the rotor 4, in particular guided with one translational degree of freedom, as can for example be seen from FIG. 20. The vanes 13 are rotated along with the rotor 4. The pump 1 comprises an annular housing part, namely a stroke ring 12. The stroke ring 12 is trapped between a first housing part 2 and a second housing part 3 and is non-rotational in relation to the first and second housing parts 2, 3. The space which extends annularly around the pump shaft 10, and which is surrounded by the inner circumference of the stroke ring 12 and axially delineated by the first and second housing parts 2, 3, can also be referred to as the pump chamber 26. The rotor 4 and the vanes 13 are arranged in the pump chamber 26.

(23) As can best be seen from FIG. 20, at least one delivery chamber 27, 28 is formed radially between the rotor 4 and the stroke ring 12. The embodiment shown here comprises two delivery chambers 27, 28, namely a first delivery chamber 27 and a second delivery chamber 28 (FIG. 20).

(24) A delivery cell 29 is respectively formed between adjacent vanes 13 and changes its volume as a function of the rotational position of the rotor 4 about its rotational axis R. Since the pump comprises a number of vanes 13, it also exhibits a corresponding number of delivery cells 29. A number of delivery cells 29 are situated in each of the delivery chambers 27, 28.

(25) The vanes 13 and the rotor 4 form a first sealing gap with the first housing part 2 and a second sealing gap with the second housing part 3.

(26) The stroke ring 12 and/or the vanes 13 can be magnetised, such that the vanes 13 abut the inner circumferential surface of the stroke ring 12 due to magnetic force, including in particular when the rotor 4 is not being rotated. This allows pressure to be built up in good time during a start or cold start, i.e. when the pump shaft 10 begins to be rotated. Alternatively or additionally, the vanes 13 can be pressed outwards, i.e. away from the rotational axis R of the rotor 4 and towards the inner circumferential surface of the stroke ring 12, due to the centrifugal force while the rotor 4 rotates. The vanes 13 and/or each of the vanes 13 forms a third sealing gap with the inner circumferential surface of the stroke ring 12.

(27) The inner circumferential surface of the stroke ring 12 exhibits a contour which causes the vanes 13 to extend (increasing the volume of the delivery cell 29) at least once and to retract (decreasing the volume of the delivery cell 29) at least once during one complete revolution of the rotor 4. The pump shown in the example is a twin-stroke pump, i.e. comprises two delivery chambers 27, 28, wherein the vanes 13 for each delivery chamber 27, 28 extend once and retract once when they are moved through the delivery chamber 27, 28 by means of rotating the rotor 4. This means that the vanes 13 extend, retract, extend and retract again—in other words, extend twice and retract twice—during one complete revolution of the rotor 4. A delivery cell 29 is respectively formed between adjacent vanes 13 and is increased and/or decreased in volume by extending and retracting the vanes 13 which delineate it, namely as a function of the contour of the inner circumferential surface of the stroke ring 12.

(28) As can be seen in particular from FIG. 3, the pump insert 1 comprises a first outlet channel 3b and a second outlet channel 3c, wherein the first outlet channel 3b ports into a first pressure space 23b and a first delivery chamber 27 (FIG. 20) and therefore connects the first delivery chamber 27 and the first pressure space 23b to each other in a liquid-guiding connection. The second outlet channel 3c ports into a second delivery chamber 28 and the second pressure space 23c, thus connecting the second delivery chamber 28 (FIG. 20) and the second pressure space 23c in a liquid-guiding connection. The first and second outlet channels 3b, 3c each port into the region of their respective delivery chamber 27, 28 in which the volume of the delivery cells 29 decreases while the rotor 4 rotates. This means that fluid, such as for example oil, situated in the delivery cells 29 is displaced through the outlet channels 3b, 3c.

(29) The pump insert 1 comprises a first inlet channel 2b and a second inlet channel 2c, wherein the first inlet channel 2b ports into the first delivery chamber 27 and a suction space 24 and therefore connects the first delivery chamber 27 and the suction space 24 in a liquid-guiding connection, and wherein the second inlet channel 2c ports into the second delivery chamber 28 and the suction space 24 and therefore connects the second delivery chamber 28 and the suction space 24 in a liquid-guiding connection. The first and second inlet channels 2b, 2c each port into the region of their respective delivery chamber 27, 28 in which the volume of the delivery cells 29 increases while the rotor 4 rotates. This means that fluid is delivered or suctioned through the first and second inlet channels 2b, 2c into the expanding delivery cell 29.

(30) When the rotor 4 rotates, fluid—in particular, liquid—is suctioned through the channel 2b, 2c into the expanding delivery cells 29 and transported into the region which the outlet channel 3b, 3c ports into, wherein the fluid is outputted from the then-contracting delivery cells 29 via the first outlet channel 3b and/or second outlet channel 3c.

(31) The pump insert 1 comprises at least one positioning element 6 (two positioning elements 6 in the example shown). The positioning elements 6 are pins and/or are pin-shaped. The positioning element 6 is firmly anchored in the first housing part 2. The first housing part 2 comprises a blind bore 2a into which a first end of the pin-shaped positioning element 6 is pressed.

(32) The pin-shaped positioning element 6 positions the second housing part 3 and the stroke ring 12 with respect to their angular positions about the rotational axis R relative to the first housing part 2. The second housing part 3 and the stroke ring 12 comprise cavities, apertures, bores or elongated holes, preferably exhibiting a radial extent, through which the positioning element 6 extends. In the example shown, the stroke ring 12 comprises a bore 12a for the first positioning element 6 and another bore 12a for the second positioning element 6 for this purpose. The second housing part 3 comprises a transit bore through which the positioning element 6 extends. The pin-shaped second end of the positioning element 6 protrudes past the end-facing side which points away from the pump chamber 26. This protruding portion of the positioning element 6 comprises a cavity, such as for example an annular groove 6a, or at least a part thereof, which extends over the circumference of the positioning element 6. A fastening element 5a of the spring 5 is arranged in the cavity 6a and fastened to the positioning element 6 and/or in the annular groove 6a, in particular in a force fit and/or positive fit. The fastening element 5a prevents the first housing part 2, the second housing part 3 and the stroke ring 12 from axially falling apart; in other words, it prevents the second housing part 3 and the stroke ring 12 from being removed from the positioning element 6. The spring 5 is thus also captively fastened to the pump insert 1, in particular the positioning elements 6.

(33) The pump shaft 10 is rotatably mounted on the first and second housing part 2, 3, in particular by means of a slide bearing in each case. As an alternative to a pump shaft 10 which is mounted on both sides, the pump shaft 10 can manage without the mounting in the second housing part 3 or with only the mounting in the first housing part 2, in particular when the pump insert 1 is a twin-stroke pump insert, i.e. comprises two delivery chambers 27, 28 which for example lie opposite in relation to the rotational axis R. As a result, the forces transverse to the rotational axis R which are caused by the pressures in the delivery chambers 27, 28 can be approximately eliminated.

(34) An outer structure, such as for example an outer toothed gearing, is formed on the pump shaft 10 between the portion of the pump shaft 10 which is rotatably mounted in the second housing part 3 and the portion of the pump shaft 10 which is rotatably mounted in the first housing part 2, and is in a positive-fit engagement with a corresponding inner structure, in particular an inner toothed gearing of the rotor 4, in order to form a shaft-hub connection 30. The outer diameter of the outer structure of the pump shaft 10 is larger than the diameter of the portion of the pump shaft 10 which is mounted in the first housing part 2 and/or in the second housing part 3. The pump shaft 10 is arranged, axially fixed, between the first and second housing parts 2, 3, i.e. such that shifting the pump shaft 10 along or in the direction of the rotational axis R is substantially impossible in both directions. For this purpose, the inner diameter of the portions of the first housing part 2 and second housing part 3 which mount the pump shaft 10 is smaller than the outer diameter of the outer structure of the pump shaft 10.

(35) The end-facing side of the first housing part 2 which points away from the pump space 26 comprises an annular pocket in which a shaft seal 11 is arranged which is fastened, rotationally fixed, to the first housing part 2 and forms a sealing gap with the pump shaft 10. The shaft seal 11 seals off the pump space 26 with respect to the outside.

(36) The end of the pump shaft 10 which lies opposite the end arranged in the region of the spring 5 comprises an outer structure for a shaft-hub connection 30 comprising a drive wheel, in particular a toothed wheel 21, in particular a sprocket. The toothed wheel 21 is seated non-rotationally on the pump shaft 10. The toothed wheel 21 can be driven by a chain which is in turn driven by for example a crankshaft or other shaft which can be connected to for example an engine of the vehicle. For fastening it to the pump shaft 10, the toothed wheel 21 comprises for example an inner thread via which it is screwed to an outer thread of the pump shaft 10, up against a collar of the pump shaft 10. A rotational securing device which is seated, secured against rotating, on the shaft 10 secures the toothed wheel 21 against becoming unintentionally detached. Alternatively, the drive wheel 21 can be joined or fastened to the pump shaft 10 by means of an interference fit assembly or other types of connection.

(37) In the examples shown, the pump insert 1 is inserted into an accommodating housing, for example a cup-shaped accommodating housing 20, such as for example a housing cup (FIG. 1). The accommodating housing 20 comprises a circumferential wall 20d which circumferentially surrounds one of the pump inserts 1 shown here. The accommodating housing 20 also comprises an end-facing wall 20c which is monolithically connected to the circumferential wall 20d, wherein the spring 5 is supported on the end-facing wall 20c, in particular axially, i.e. in the direction of the rotational axis R.

(38) The pump insert 1 is held between the end-facing wall 20c and an axial securing element, such as for example a screw, an axial securing ring, or a cover, such that the spring 5 is or is kept tensed, in particular pressurised. The axial securing element can in particular abut the first housing part 2 and/or hold the first housing part 2 on the accommodating housing 20, secured against shifting along or in the direction of the rotational axis R.

(39) The first pressure space 23b, into which the fluid (liquid) delivered by the pump is delivered, is formed between the end-facing wall 20c and a second seal 8 which is arranged in an annular groove formed on the outer circumference of the second housing part 3 and which forms a sealing gap with the circumferential wall 20d. The pressure space 23b is in turn connected to a fluid consumer, such as for example a lubricant consumer, in particular a transmission, by means of a channel (not shown). An annular seal 9 which is arranged between the end-facing wall 20c and the second housing part 3 annularly surrounds the second pressure space 23c and seals it off in relation to the first pressure space 23b. The seal 9 therefore forms a wall of the first pressure space 23b and second pressure space 23c. The fluid delivered by the pump is delivered into the second pressure space 23c. The second pressure space 23c is in turn connected to a fluid consumer, such as for example a lubricant consumer, by means of a channel (not shown).

(40) The seal 9 is arranged in a seal groove or seal pocket of the second housing part 3 which annularly surrounds one end of the second outlet channel 3c, wherein the base of the groove or pocket forms a sealing surface for the seal 9. The wall of the groove or pocket which annularly surrounds the seal exhibits a distance from the end-facing wall 20c which is less than the height of the seal 9, in particular less than the height of the first ring 9a which is described further below. Any gap extrusion of the seal 9 is prevented by the first ring 9a, in particular the material of the first ring 9a, and/or by the smaller gap width between the wall and the end-facing wall 20c. Gap extrusion can also be prevented by a supporting structure in the seal 9.

(41) A suction space 24, from which fluid is delivered into the first pressure space 23b and/or the second pressure space 23c via the first delivery chamber 27 and the second delivery chamber 28, is formed between the second seal 8 and the first seal 7 which is arranged in an annular groove arranged on the outer circumference of the first housing part 2 and which forms a sealing gap with the circumferential wall 20d. The suction space 24 can for example be connected by means of a channel to a storage container for the fluid, into which the fluid consumed by the consumer can for example flow back. When the fluid is being delivered, the pressure in the pressure spaces 23b, 23c is increased as the rotational speed increases, whereby the second housing part 3 jams the stroke ring 12 firmly between the first and second housing part 2, 3, in addition to the biasing force of the spring 5. The first and second housing parts 2, 3 and the stroke ring 12 are thus sealed off with respect to each other. The connection between the axial securing element and the first housing part 2 is embodied to be strong enough that it can withstand, i.e. is not detached by, the axial force on the axial securing element, as generated by the pressure in the pressure spaces 23b, 23c. In the example shown, the axial securing element is a housing cover which is fastened to the accommodating housing 20 and on which the first housing part 2 is axially supported.

(42) An expediently designed corrugated annular spring, a multi-corrugated spring disc, a tube spring or bow spring, a grooved annular spring, a metal O-ring or a metal C-ring may for example be considered for the spring 5. If the spring 5 is to be fastened to the positioning elements 6, the spring 5 can comprise fastening elements 5a for fastening it to the positioning elements 6.

(43) FIG. 4 shows a first embodiment of a spring 5 which is embodied as a corrugated annular spring. The corrugated annular spring 5 comprises an annular spring structure 5b which is corrugated over its circumference, i.e. which comprises a number of corrugations, i.e. corrugation peaks and troughs. The corrugation peaks can for example abut the end-facing wall 20c, and the corrugation troughs can for example abut the second housing part 3. The corrugation height extends approximately parallel to the rotational axis R. The spring 5 is produced, in particular punched, from a flat material. The circumference of the spring 5 comprises a number of fastening elements 5a (in this case, two) in the form of cavities which are open towards the inner circumference and can be arranged in the annular groove 6a of a positioning element 6. The thickness of the flat material of the spring 5 is less than the groove width of the annular groove 6a. The spring 5 from FIG. 5 is to this extent identical to the spring 5 from FIG. 4. The spring 5 from FIG. 4 additionally comprises a number of inwardly protruding projections on its inner circumference. This enables the distribution of stress in the spring to be comparatively adapted in the event of deformation and/or the spring bias and spring rate to be adapted to requirements.

(44) The spring 5 from FIG. 6 substantially corresponds to the embodiment from FIG. 5, wherein the spring structure 5b from FIG. 6 comprises more corrugations, i.e. is more significantly corrugated, than the embodiment from FIG. 5. In addition, the spring structure 5b comprises a positioning element 5e which can engage with a corresponding cavity in the second housing part 3 in order to fasten the spring 5 to the positioning elements 6 in the correct position.

(45) FIG. 7 shows an annular spring 5 which comprises a number of tubular portions 5f—in this example, two tubular portions 5f—over its circumference. A fastening element 5a, in particular a flat portion 5g in which the fastening element 5a is formed, is arranged between adjacent tubular portions 5f. The fastening element 5a is a cavity which is open towards the inner circumference of the ring. The thickness of the flat portion 5g is less than the groove width of the annular groove 6a of the positioning element 6. The flat portion 5g can be formed by compressing and plastically deforming a previously continuous tubular portion 5f. In the example shown, two fastening elements 5a and therefore two flat portions 5g are provided. The spring 5 also comprises two tubular portions 5f which are respectively connected at their ends via a flat portion 5g which is provided with a fastening element 5a.

(46) The embodiment from FIG. 8 shows a spring 5 which is identical to the spring from FIG. 7 except for the configuration of the tubular portions 5f. For instead of a tubular portion 5f, the embodiment from FIG. 8 comprises C-shaped portions 5h. Reference is otherwise made to the embodiment from FIG. 7. The C-shaped portions 5h each exhibit a contour which has an open cross-section, i.e. a slot, which extends over the circumference, in particular the inner circumference of the annular spring structure.

(47) The springs 5 and/or spring structures 5b from FIGS. 4 to 8 are preferably formed from metal, in particular spring steel. The springs 5 can additionally be coated, in particular in a plastic such as for example a polymer or an elastomeric or thermoplastic material or for example a varnish, or such materials can additionally be injection-moulded around the springs 5.

(48) FIG. 9 shows an annular seal 9 which comprises a first sealing ring 9a made of a first material and a second sealing ring 9b made of a second material. The first ring 9a and second ring 9b can be integrally connected to each other, in particular in a material fit. The first ring 9a serves to stabilise the annular seal 9, wherein the second ring 9b primarily serves to ensure the sealing function. Reference can in principle be made here to EP 0 415 089 A2 in which such integral sealing rings are described. Plastic, in particular thermoplastics, which can be selected so as to exhibit the required characteristics, are suitable as the material for the first ring 9a. Polytetrafluoroethylene (PTFE) is in particular suitable; its core strength can be further increased using inlaid fibres, for example glass fibres, such that the axial seal can withstand significant pressures. Ethylene tetrafluoroethylene (ETFE) copolymer may also be considered as a material for the first ring 9a, not least because this material is easy to process. Polyterephthalate is also well suited to the envisaged purpose, since it can be easily vulcanised to the sealing ring. Polyamides, with or without inlaid glass fibres, are also suited to the envisaged purpose. The second ring 9b is preferably made of a plastic, in particular an elastomeric or rubbery-elastic material or elastomer, which can preferably be easily vulcanised, does not tear and does not exhibit high notch sensitivities. The materials listed also apply in particular, but not solely, to the embodiments from FIGS. 10, 11, 15 and 16, and can for example be used in any of the embodiments shown or described in the present application.

(49) In FIG. 9, the first ring 9a comprises a groove, which extends in a V shape, over its circumference. A counter piece which is adapted to the shape of this groove and which is formed by the second ring 9b is arranged in the groove and connected, in particular vulcanised or glued, to the first ring 9a in the groove.

(50) In FIG. 10, the first ring 9a again comprises a V-shaped groove which extends over the circumference of the first ring 9a; the second ring 9b is an O-ring which has a circular cross-section. The second ring 9b is again arranged in the V-shaped groove and connected to the first ring 9a, in particular in a material fit, in the groove. In the embodiment from FIG. 11, the first ring 9a comprises a planar surface which faces the second ring 9b and on which the O-ring-shaped second ring 9b lies and to which the second ring 9b is fastened in a material fit.

(51) FIG. 15 shows a first ring 9a which comprises a tier circumferentially over its annular circumference, wherein the second ring 9b, which is embodied as an O-ring, is accommodated in said tier. The second ring 9b is connected to the first ring 9a in a material fit. Optionally, the second ring 9b is loosely inserted into the first ring 9a, in particular into the tiered collar.

(52) The end-facing side of the end of the seal 9 which lies opposite the end-facing side of the end formed by the second ring 9b comprises at least one circumferential groove over the annular circumference of the first ring 9a. The groove is enclosed by a first, in particular inner circumferential groove wall 9c and a second, in particular outer circumferential groove wall 9d.

(53) The first groove wall 9c is continuous over the circumference and supported on its sealing surface, forming a seal, thus sealing off the first pressure space 23b with respect to the second pressure space 23c. The second groove wall 9d is provided with a number of cavities over its circumference which make the second groove wall 9d permeable to liquid, hence only the first groove wall 9c seals off the pressure spaces. The second groove wall 9d serves to support the seal 9 on the sealing surface, so that the seal 9 does not tilt.

(54) Alternatively, the second groove wall 9d can be continuous over the circumference, and the first groove wall 9c can be provided with the number of cavities, wherein the above description can be applied analogously to this embodiment, i.e. the second groove wall 9d can primarily serve a sealing function and the first groove wall 9c can primarily serve a supporting function.

(55) FIG. 16 shows a seal 9 which consists of only one ring which is for example made of the material for the aforementioned first ring 9a or the aforementioned second ring 9b, depending on the expected pressure difference between the first pressure space 23b and the second pressure space 23c. An end-facing side of the end of the seal 9 is embodied with a sealing lip which comprises an inclined inner surface which is inclined such that an internal pressure in the second pressure space 23c exerts a force on the sealing lip, at least a portion of which presses against the sealing surface of the second housing part 3 or end-facing wall 20c. A multitude of cavities, which for example extend along the height of the seal 9 or in the direction of the rotational axis R, are arranged on the inner circumference and are for example open towards the inner circumference in order to ensure that pressure fluid from the second pressure space 23c is applied to the sealing lip, even when it is deformed when the pump insert 1 is incorporated in the accommodating housing 20, in order to press it against its sealing surface which is for example formed by the second housing part 3. The end-facing side of the seal 9 which lies opposite the sealing lip can be flat or level or embodied as in FIG. 15.

(56) FIG. 12 shows an annular seal 9 which comprises a first ring 9a made of the aforementioned first material or alternatively made of metal, in particular steel. This first ring is coated substantially completely over its surface in plastic, in particular the elastomeric or rubbery-elastic or thermoplastic material, or said material is injection-moulded around it, thus forming a second ring 9b.

(57) FIG. 13 shows an annular seal 9 which comprises a first ring 9a which is configured as an annularly circumferential tube. As an alternative to the materials mentioned for the first ring 9a, the ring 9a can for example consist of a metallic spring material, in particular spring steel. The annularly circumferential tube 9a can comprise a closed wall or can for example be wound from a helical spring.

(58) The first ring 9a is coated over its outer circumference in plastic, in particular the elastomeric or rubbery-elastic or thermoplastic material, or said material is injection-moulded around it, thus forming a second ring 9b which surrounds the first ring 9a. The tube 9a from FIG. 13 can therefore act as a spring, and the coating or the surrounding injection-mould 9b can therefore act as a seal 9. The same applies analogously to the embodiment from FIG. 14.

(59) The embodiment from FIG. 14 shows a first ring 9a which is formed from a slotted tube or C-shaped profile which is circumferential and shaped as a closed ring. The slot in the C-shaped profile or slotted tube 9a points towards the interior and therefore towards the second pressure space 23c. The first ring 9a is coated over its outer circumference in plastic, in particular the elastomeric or rubbery-elastic or thermoplastic material, or said material is injection-moulded around it, thus resulting in a second ring 9b which at least partially surrounds the first ring 9a.

(60) FIG. 19 shows an embodiment of a spring 5 which is combined with a seal 9 and which is shown in FIGS. 17 and 18 in combination with the pump insert 1.

(61) The spring 5 from FIG. 19 comprises an annular spring structure 5b featuring a first spring structure ring 5k which extends, in particular concentrically, around the rotational axis R. The spring structure 5b is formed from metal, in particular steel, which imbues the spring 5 with its essential spring characteristics in the direction of the rotational axis R. The annular spring structure 5b comprises a number of arms 5c which protrude inwards from the first spring structure ring 5k and are distributed over its circumference, wherein the inwardly protruding ends of the arms project freely. The arms 5c each comprise a contact surface 5d via which they abut the end-facing wall 20c. The lower side of the first spring structure ring 5k of the spring structure 5b abuts the second housing part 3 in the region which is arranged in axial alignment with the stroke ring 12 in the direction of the rotational axis R. The first spring structure ring 5k comprises two fastening elements 5a which are formed as continuous cavities, such as for example bores or elongated holes. The bore or elongated hole is surrounded, over at least some of its circumference, by a wall which exhibits a thickness, extending along or in the direction of the rotational axis R, which is smaller than the groove width of the annular groove 6a of the positioning element 6. A part of this wall can thus latch into the annular groove 6a, thus captively fastening the spring 5 to the at least one positioning element 6. For inserting the positioning elements 6 into the continuous cavities of the fastening elements 5a, the spring structure ring 5k can for example be elastically pressed together or apart along an imaginary connecting line between the two fastening elements 5a, in order to enable it to be fitted onto the positioning elements 6 and, by releasing it, enable a part of the wall to latch into the annular groove 6a.

(62) The spring structure 5b comprises a second spring structure ring 5j which annularly surrounds the second pressure space 23c. The spring structure 5b also comprises a third spring structure ring 5i which extends around the rotational axis R and is arranged within the first spring structure ring 5k from which the arms 5c project. At least the second spring structure ring 5j and preferably—if provided—also the third spring structure ring 5i and optionally also the first spring structure ring 5k is/are coated in plastic, in particular the elastomeric or rubbery-elastic or thermoplastic material, or said material is injection-moulded around it/them at least partially or completely, such that at least the ends of the second ring (which comprises the second spring structure ring 5j) and third ring (which comprises the third spring structure ring 5i) which point in the direction of the rotational axis R are formed with a surface made of plastic, in particular the elastomeric or rubbery-elastic or thermoplastic material. The elastomeric or rubbery-elastic or thermoplastic material also separates the second pressure space 23c from the first pressure space 23b. The second ring, together with its surrounding injection-mould or coating, can therefore be defined as a seal 9. The third ring, together with its coating or surrounding injection-mould, seals off the bore in the second housing part 3, in which a portion of the pump shaft 10 is arranged, with respect to the first pressure space 23b and the second pressure space 23c. The surrounding injection-mould or coating of the third ring is supported on the second housing part 3 and oppositely on the end-facing wall 20c.

LIST OF REFERENCE SIGNS

(63) 1 pump insert

(64) 2 first housing part

(65) 2a cavity, such as for example a blind bore

(66) 2b first inlet channel

(67) 2c second inlet channel

(68) 3 second housing part

(69) 3a cavity, such as for example a transit bore

(70) 3b first outlet channel

(71) 3c second outlet channel

(72) 4 rotor

(73) 5 spring

(74) 5a securing element/fastening element

(75) 5b spring structure

(76) 5c arm

(77) 5d contact surface

(78) 5e positioning element

(79) 5f tubular portion

(80) 5g flat portion

(81) 5h slotted tubular portion

(82) 5i third spring structure ring

(83) 5j second spring structure ring

(84) 5k first spring structure ring

(85) 6 positioning element/pin

(86) 6a cavity, such as for example an annular groove

(87) 7 first seal/sealing ring

(88) 8 second seal/sealing ring

(89) 9 sealing element/seal/sealing ring/axial seal

(90) 9a first ring

(91) 9b second ring

(92) 9c first groove wall

(93) 9d second groove wall

(94) 10 pump shaft

(95) 11 shaft seal

(96) 12 stroke ring

(97) 12a bore

(98) 13 delivery element/vane

(99) 20 accommodating housing, such as for example a housing cup

(100) 20c end-facing wall

(101) 20d circumferential wall

(102) 20e opening

(103) 21 toothed wheel, such as for example a sprocket

(104) 23b first pressure space

(105) 23c second pressure space

(106) 24 suction space

(107) 25 accommodating space

(108) 26 pump space/pump chamber

(109) 27 first delivery chamber

(110) 28 second delivery chamber

(111) 29 delivery cell

(112) 30 shaft-hub connection

(113) R rotational axis