AXIAL PRESSURE RELIEF IN SLIDE BEARINGS OF PUMPS

Abstract

A pump is described, including: a drive shaft including a rotor; a first housing part and a second housing part, between which a pump chamber is formed, in which the rotor is arranged; a rotary bearing via which the drive shaft is mounted on the first housing part such that it can rotate about its rotational axis; and a passage including a first opening and a second opening, wherein the rotary bearing is arranged between the pump chamber and the first opening, and the second opening of the passage emerges onto the side of the second housing part which faces away from the pump chamber.

Claims

1.-15. (canceled)

16. A pump, comprising: a drive shaft comprising a rotor; a first housing part and a second housing part, between which a pump chamber is formed, in which the rotor is arranged; a rotary bearing via which the drive shaft is mounted on the first housing part such that it can rotate about its rotational axis; and a passage comprising a first opening and a second opening, wherein the rotary bearing is arranged between the pump chamber and the first opening, and the second opening of the passage emerges onto the side of the second housing part which faces away from the pump chamber.

17. The pump according to claim 16, wherein the second housing part is a fitting plate and/or comprises a fastening flange adapted to fasten the second housing part to an accommodating housing.

18. The pump according to claim 16, wherein the drive shaft comprises the passage comprising the first opening and the second opening.

19. The pump according to claim 16, wherein at least one of the first housing part, the second housing part, a contour ring or a positioning element comprises the passage or part of the passage.

20. The pump according to claim 19, wherein the first housing part comprises the first opening, and the second housing part or the positioning element comprises the second opening.

21. The pump according to claim 16, further comprising a hollow space which is formed between a base of a blind hole formed by the first housing part and a first end of a drive shaft which is arranged in the first housing part, wherein the first opening of the passage emerges into the hollow space.

22. The pump according to claim 21, wherein the first rotary bearing is arranged between the pump chamber and the hollow space.

23. The pump according to claim 16, wherein the second opening emerges into the environment of the pump or a pump insert.

24. The pump according to claim 23, wherein the environment is outside an accommodating space of an accommodating housing in which the pump insert is accommodated.

25. The pump according to claim 16, wherein the drive shaft comprises a connecting structure, which is adapted to be connected to a hub, on the side of the second housing part which faces away from the pump chamber.

26. The pump according to claim 25, wherein an environment of the pump or pump insert or a relief space is formed on the side of the second housing part which faces away from the pump chamber, wherein the environment or the relief space is adapted to accommodate the hub to which the connecting structure is connectable, wherein the second opening of the passage emerges into the environment or the relief space.

27. The pump according to claim 26, wherein the relief space is connected to a reservoir or to the suction side or to a suction space of the pump, in order to feed fluid back from the relief space.

28. The pump according to claim 27, wherein the relief space is connected to the atmosphere, such that atmospheric pressure prevails in the relief space while the pump is in operation.

29. The pump according to claim 16, wherein the pump is a multi-stroke pump or a dual-stroke pump.

30. The pump according to claim 16, wherein the pump is a multi-flux pump or a dual-flux pump.

31. The pump according to claim 16, further comprising a first pressure space and a second pressure space, wherein the pump chamber is connected to the first pressure space via a first outlet channel and to the second pressure space via a second outlet channel, wherein the first pressure space and the second pressure space are sealed off in relation to each other.

32. The pump according to claim 31, wherein at least one of the first pressure space and the second pressure space is formed between an end-facing wall of an accommodating space and the first housing part.

33. The pump according to claim 31, wherein a suction space is formed between a circumferential wall of the accommodating space and a pump insert or a contour ring.

34. The pump according to claim 16, further comprising a second rotary bearing, via which the drive shaft is mounted on the second housing part such that it can rotate about its rotational axis, and a shaft gasket, wherein the second rotary bearing is arranged between the shaft gasket and the pump chamber.

35. The pump according to claim 16, wherein the drive shaft together with the rotor, and the first housing part and second housing part, are components of a pump insert which is inserted or adapted to be inserted as a unit into an accommodating space formed by an accommodating housing.

36. A gearbox comprising a gear housing and a gear shaft which is connected via a drive element to the drive shaft of the pump according to claim 16, such that rotating the gear shaft causes the drive shaft to rotate, wherein the gear housing encloses the relief space and/or forms an accommodating space.

37. The gearbox according to claim 36, wherein the pump comprises a pump insert which is arranged in the accommodating space, wherein the accommodating space is sealed off in relation to the environment or the relief space.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The invention has been described on the basis of embodiments and examples. An embodiment will now be described on the basis of a FIGURE. The features thus disclosed, each individually and in any combination of features, advantageously develop the subject-matter of the claims. The FIGURE shows a section through a pump insert 1, which is inserted into an accommodating housing 100, along the rotational axis D of a drive shaft 10.

DETAILED DESCRIPTION OF THE INVENTION

[0039] The pump insert 1 comprises a first housing part 20, which is embodied as a pressure plate, and a second housing part 30 which is embodied as a fitting structure or fitting plate. A pump chamber 50 which is formed between the first and second housing parts 20, 30 is surrounded and/or defined on its circumferential side by an inner circumferential surface of a contour ring 2 which forms an inner contour. The first housing part 20, the second housing part 30 and the contour ring 2 are positioned with respect to each other in relation to their angular position around the rotational axis D by means of pin-shaped positioning elements 6. The at least one pin-shaped positioning element 6 is anchored in a bore of the second housing part 30. The positioning element 6 can for example be pressed, screwed, soldered, welded or glued into the second housing part 30. The contour ring 2 and the first housing part 20 each comprise passages through which the positioning element 6 extends. This enables the first and second housing parts 20, 30 and the contour ring 2 to be positioned and/or angularly positioned in relation to each other around the rotational axis D. The housing parts 2, 20, 30 can also be held together by means of the positioning elements 6 in order to be able to handle them as a unit and/or as a pump insert 1.

[0040] A spring 5 which is arranged between the end-facing wall 103 of the accommodating housing 100, which defines the accommodating space 102 on its end-facing side, and the first housing part 20 presses and/or tenses the first housing part 20 against the contour ring 2 and preferably in turn presses and/or tenses the contour ring 2 against the second housing part 30 when the pump insert 1 is inserted into the accommodating housing 100 and/or the accommodating space 102 of the accommodating housing 100. The spring 5 is supported on the end-facing wall 103 and on the first housing part 20 and exerts a force on the first housing part 20 which is directed away from the end-facing wall 103 and in particular points along the rotational axis D or the longitudinal direction of the positioning elements 6.

[0041] The spring 5 can for example be inserted, as a separate part, between the end-facing wall 103 and the pump insert 1 when the pump insert 1 is introduced into the accommodating space 102. In the example shown, however, the spring 5 is captively fastened to the pump insert 1, such that the spring 5 can be handled together with the pump insert 1 as a unit. It is therefore part of the pump insert 1. The spring 5 can for example be fastened to the pump insert 1 as is described in German patent application No. 10 2020 116 731.8.

[0042] In the example shown, a first pressure space and a second pressure space (not visible in the FIGURE) are formed between the end-facing wall 103 of the accommodating space 102 and the first housing part 20. The pump chamber 50 is connected to the first pressure space via a first outlet channel (not visible in the FIGURE) and to the second pressure space via a second outlet channel (not visible in the FIGURE). The pump shown is thus a dual-flux pump, i.e. the pump generates a first working flux, which is outputted from the pump chamber 50 into the first pressure space, and a second working flux which is outputted from the pump chamber 50 into the second pressure space. The first pressure space and the second pressure space are sealed off in relation to each other. This enables different fluid consumers or different supply branches to a common fluid consumer to be supplied with fluid. Optionally, this also enables different pressure levels to be generated in the first and second pressure spaces.

[0043] The first pressure space is surrounded and/or enclosed by a sealing element arranged between the end-facing wall 103 of the accommodating space 102 and the first housing part 20. The sealing element rests against the first housing part 20 and the end-facing wall 103 in a seal.

[0044] The second pressure space is surrounded and/or enclosed by a sealing element arranged between the end-facing wall 103 and the first housing part 20. This sealing element rests against the first housing part 20 and the end-facing wall 103 in a seal.

[0045] In the example shown, the first pressure space and the second pressure space are sealed off by a common sealing element 40, in particular a so-called bead gasket. In principle, however, separate sealing elements can also be provided for the first and second pressure spaces, or the seal can be achieved in a different way.

[0046] Advantageously, the sealing element 40 can be captively fastened to the positioning elements 6 and/or to the pump insert 1, for example by means of stud-bolts which are screwed into an internal thread of the positioning elements 6. The sealing element 40 can for example be embodied as is described in German patent applications 10 2019 132 729.6 and 10 2020 116 731.8, each incorporated herein by reference.

[0047] A suction space 101 which is formed between an inner circumferential wall 104 of the accommodating space 102 and the housing insert 1, in particular the contour ring 2, extends annularly around the pump insert 1 and/or the contour ring 2. The pump is adapted to deliver fluid from the suction space into the first pressure space via a first suction channel (not visible in the FIGURE), the pump chamber 50 (in particular, a first delivery chamber formed in the pump chamber) and the first outlet channel (the first working flux). The pump is also adapted to deliver fluid from the suction space 101 into the second pressure space via a second suction channel (not visible in the FIGURE), the pump chamber 50 (in particular a second delivery chamber formed in the pump chamber (50) and the second outlet channel (the second working flux).

[0048] The suction space 101 is arranged between a first sealing ring 8 and a second sealing ring 7. The sealing ring 8 is arranged between the circumferential wall 104 of the accommodating space 102 and the first housing part 20. The first housing part 20 comprises an annular groove which encircles the outer circumference of the first housing part 20 and in which the sealing ring 8 is arranged. The sealing ring 8 rests against the inner circumferential wall 104 and the first housing part 20, in particular the base of the annular groove, in a seal. The sealing ring 7 is arranged between the inner circumferential wall 104 and the second housing part 30. The sealing ring 7 is arranged in an annular groove which encircles the outer circumference of the second housing part 30. The sealing ring 7 rests against the inner circumferential wall 104 and the second housing part 30, in particular the base of the annular groove, in a seal.

[0049] A drive shaft 10 (pump shaft) is mounted, such that it can rotate about the rotational axis D, on the first housing part 20 by means of a first rotary bearing 22 which is embodied as a slide bearing, in particular in a blind hole or a blind bore, and on the second housing part 30 by means of a second rotary bearing 32 which is embodied as a slide bearing. A rotor 4 which is arranged together with delivery elements 3 in the pump chamber 50 is connected and/or joined to the drive shaft 10, such that it is rotationally fixed about the rotational axis D, by means of a shaft-hub connection 14, such that the rotor 4 rotates together with the drive shaft 10 during operation. The rotor 4 comprises guide slots in which the delivery members 3, which are embodied as vanes, are arranged. During operation, the delivery elements 3 slide along an inner contour and/or inner circumferential surface of the contour ring 2. Since the pump is embodied as a dual-flux and/or dual-stroke pump, the inner contour is embodied such that the vanes 3 extend out of the slot-shaped guides twice and retract into the slot-shaped recesses twice during one complete revolution of the rotor 4.

[0050] The drive shaft 10 comprises a passage 11 which in particular acts as a pressure relief channel. As an alternative to the embodiment described in the FIGURE, the passage which acts as a pressure relief channel can be embodied differently, for example in that the first housing part 20, the contour ring 2 and/or the positioning element 6 and the second housing part 30 form the passage. The passage 11 comprises a first opening 12 at the first end of the drive shaft 10, which is the end arranged in the first housing part 20, in particular the blind hole, and a second opening 13 at the second end of the drive shaft 10. The first rotary bearing 22 is arranged between the pump chamber 50 and the first opening 12 and/or a hollow space 21. The hollow space 21 is formed between the base of the blind bore, which lies opposite the first end of the drive shaft 10, and the first end of the drive shaft 10. The first opening 12 of the passage 11 emerges into the hollow space 21. Furthermore, the second opening 13 of the passage 11 emerges onto the side of the second housing part 30 which faces away from the pump chamber 50. This arrangement means that pressure fluid from the pump chamber 50, which for example flows as so-called leakage fluid into the hollow space 21 via the first rotary bearing 22, is drained via the passage 11, for example into a relief space 55 which is indicated in the FIGURE by a double-dot-dashed line and for example enclosed by a gearbox housing which in particular also forms the accommodating housing 100. This means that pressure, which can exert an axial thrust on the drive shaft 15, cannot accumulate in the hollow space 21. If the passage 11 were not provided, there would be a risk of pressure accumulating in the hollow space 21 which would exert an axial thrust on the drive shaft 15, leading to increased friction, increased wear and decreased efficiency of the pump. The passage 11 thus decreases wear and friction and increases efficiency. The second end of the drive shaft 10 is arranged in the relief space 55. The drive shaft 10 comprises a connecting structure 15 on the side of the second housing part 30 which faces away from the pump chamber 50. The connecting structure 15 is adapted to be connected to a hub of a drive element (not shown in the FIGURE). The drive element can be a gear wheel, a pinion, a belt disc or a gear element of for example a planetary gear system, such as for example a planetary carrier. The hub forms a shaft-hub connection with the connecting structure 15. The drive element can be coupled to a gear shaft of the gearbox, such that rotating the gear shaft causes the drive shaft of the pump to rotate.

[0051] The hub, in particular the drive element, can be arranged in the relief space 55. The relief space 55 is arranged on the side of the second housing part 30 which faces away from the pump chamber 50. The relief space 55 can be connected, for example by means of a channel, to a reservoir or alternatively to the suction side, in particular the suction space 101 of the pump, in order to feed fluid back from the relief space 55. Alternatively or additionally, fluid drained into the relief space can be drained into the reservoir by means of gravity, for example by placing the reservoir, for example an oil sump, lower in relation to the direction of gravity than the second opening and connecting the second opening 13 and the reservoir in fluid communication.

[0052] Preferably, atmospheric pressure prevails in the relief space 55, in particular in the space enclosed by the gear housing. The passage 11 also ensures that the same pressure or at least substantially the same pressure prevails in the intermediate space 21 as in the relief space 55, i.e. preferably atmospheric pressure.

[0053] A shaft gasket 33, in particular a radial shaft sealing ring, which is accommodated in or on the second housing part 30 rests against the drive shaft 10 in a seal. The shaft gasket 33 is arranged between the second rotary bearing 32 and the connecting structure 15. Alternatively or additionally, the second rotary bearing 32 is arranged between the pump chamber 50 and the shaft gasket 33.

[0054] In developments of the embodiment shown in the FIGURE, one or more transverse bores, i.e. bores which are arranged transversely with respect to the longitudinal direction of the passage 11 or the rotational axis D, can be provided in the drive shaft 10. A transverse bore can for example be provided in the region of the shaft-hub connection 14. The transverse bore emerges into the shaft-hub connection 14 and into the passage 11. Thus, depending on the pressure conditions, a leakage fluid flow from the pump chamber 50 into the passage 11 via the shaft-hub connection 14 and the transverse bore and from the passage 11 into the relief space 55 can be generated, thus enabling fretting and wear in the shaft-hub connection to be decreased or prevented. Depending on the pressure conditions, leakage fluid can alternatively be moved through said transverse bore from the intermediate space 21 onto the shaft-hub connection 14 via the passage 11 and the transverse bore.

[0055] Alternatively or additionally, a transverse bore which emerges onto the outer circumference of the drive shaft 10 and onto the passage 11 can be provided between the pump chamber 50 and the shaft gasket 33. The transverse bore can emerge into a region on the outer circumference which is arranged between the second rotary bearing 32 and the point at which the shaft gasket 33 rests against the drive shaft 10 in a seal. This can mean that on the one hand, the shaft gasket 33 is relieved of pressure, and on the other hand, the throughput of leakage fluid from the pump chamber 50 through the second rotary bearing 32 is increased, thus enabling the second rotary bearing 32 to be better lubricated and/or cooled. The flow of leakage fluid through the first rotary bearing 22 also lubricates and/or cools the first rotary bearing 22.

[0056] Alternatively or additionally, a transverse bore can be provided in the region of the connecting structure 15, wherein the transverse bore emerges into the connecting structure 15 and into the passage 11. This can mean that leakage fluid drained through the passage 11 is moved onto the connecting structure 15 via the transverse bore and thus onto the shaft-hub connection between the hub of the drive element and the connecting structure 15. This decreases or even prevents wear and/or fretting on the connecting structure and/or the shaft-hub connection.

[0057] The second housing part 30 is embodied such that the pump insert 1 can be fastened to the accommodating housing 100. The second housing part 30 comprises a fastening flange 31 which comprises one or more bores in order to enable the second housing part 30 to be fastened to the accommodating housing 100 by means of stud-bolts. In the example shown, the longitudinal direction of the bores in the fastening flange 31 is parallel to the rotational axis D. The fastening flange 31 can be clamped between a head of the stud-bolt screwed into the accommodating housing 100 and the accommodating housing 100.

[0058] The first housing part 20 optionally comprises a journal 23 which protrudes from the end-facing surface of the first housing part 20 which faces away from the pump chamber 50 and/or faces the end-facing wall 103. The journal 23 can serve to center the sealing element 40. Alternatively or additionally, the journal 23 can serve to center the pump insert 1 or the first housing part 20 on the accommodating housing 100. The accommodating housing 100 can comprise a bore having an inner circumferential surface on which the outer circumferential surface of the journal 23 is centered.

[0059] The accommodating housing 100 can also comprise a channel which emerges into the first pressure space and via which the first working flux can flow off to the consumer. The accommodating housing can also comprise a channel which emerges into the second pressure space and via which the second working flux can flow off to the corresponding fluid consumer.

[0060] The rotor 4 and the connecting structure 15 are joined such that they are translationally fixed with respect to each other along the rotational axis D, for example by means of a securing element 16 which can for example be embodied as an axial shaft securing ring which is fitted onto the drive shaft. The rotor 4 can be arranged and/or enclosed between a stage of the drive shaft 10 and the securing element 16 which is fastened on the drive shaft 10.

LIST OF REFERENCE SIGNS

[0061] 1 pump insert [0062] 2 contour ring [0063] 3 delivery element/vane [0064] 4 rotor [0065] 5 spring [0066] 6 positioning element [0067] 7 (first) sealing element/sealing ring [0068] 8 (second) sealing element/sealing ring [0069] 9 fastening element [0070] 10 drive shaft [0071] 11 passage/bore/pressure relief channel [0072] 12 (first) opening [0073] 13 (second) opening [0074] 14 shaft-hub connection [0075] 15 connecting structure [0076] 16 securing element [0077] 20 first housing part/pressure plate [0078] 21 hollow space [0079] 22 first rotary bearing [0080] 23 journal [0081] 24 base of a blind hole [0082] 30 second housing part/fitting plate [0083] 31 fastening flange [0084] 32 second rotary bearing [0085] 33 shaft gasket [0086] 40 sealing element/bead gasket [0087] 50 pump chamber [0088] 55 relief space/environment [0089] 100 accommodating housing [0090] 101 suction space [0091] 102 accommodating space [0092] 103 end-facing wall [0093] 104 inner circumferential wall [0094] D rotational axis