VACUUM PUMP SEALING ELEMENT

Abstract

A rotary pump, preferably a vacuum. pump, featuring: a delivery space including an inlet on a low-pressure side and an outlet on a high-pressure side of the pump; a rotor which is arranged in the delivery space and delivers a fluid from the inlet into the delivery space to the outlet from the delivery space; at least one housing part which delineates the delivery space at least axially; and a drive shaft which is connected in drive terms to the rotor; including at least one sealing element which is connected, secured against shifting and/or rotating, to the drive shaft and/or rotor and forms a radial sealing gap with the housing part.

Claims

1. A rotary pump, comprising: a delivery space comprising an inlet on a low-pressure side and an outlet on a high-pressure side of the pump; a rotor which is arranged in the delivery space and delivers a fluid from the inlet into the delivery space to the outlet from the delivery space; at least one housing part which delineates the delivery space at least axially; and a drive shaft which is connected in drive terms to the rotor, wherein at least one sealing element which is connected, secured against shifting and/or rotating, to the drive shaft and/or rotor and forms a radial sealing gap with the housing part.

2. The rotary pump according to claim 1, wherein the sealing element is integrally formed by the drive shaft and/or rotor.

3. The rotary pump according to claim 1, wherein the sealing element and the housing part form an axial gap together.

4. The rotary pump according to claim 1, wherein the drive shaft is mounted in at least one bearing region in the housing part and forms a radial bearing gap with the housing part in the bearing region, wherein the radial bearing gap is smaller in the radial direction than the radial sealing gap.

5. The rotary pump according to claim 1, wherein the drive shaft is mounted in at least one bearing region in the housing part, wherein the bearing region exhibits an axial extent which is at least twice as large as an axial extent of the radial sealing gap.

6. The rotary pump according to claim 1, wherein an immersion pocket which is axially open towards the delivery space and in which the sealing element is arranged is incorporated in the housing part.

7. The rotary pump according to claim 6, wherein an axial extent of the immersion pocket is larger than a maximum axial clearance of the drive shaft.

8. The rotary pump according to claim 1, wherein the rotor comprises a sealing element on each of its two axial end-facing sides, and sealing elements exhibit identical or different outer diameters and/or identical or different axial extents.

9. The rotary pump according to claim 5, wherein the axial extent of the bearing region is larger than the sum of the axial extents of the radial sealing gaps.

10. The rotary pump according to claim 6, wherein the immersion pocket/s is/are supplied with lubricant and/or sealant by an inward flow of a lubricant and/or sealant via the radial bearing gap with or without a lubricant and/or sealant groove, or a lubricant and/or sealant supplying bore emerges into the immersion pocket/s.

11. The rotary pump according to claim 1, characterized in that wherein the rotor comprises: a delivery element support featuring at least one rotor slot; and at least one delivery element which is axially and radial guided in the rotor slot and which sub-divides the delivery space into at least two delivery cells.

12. The rotary pump according to claim 11, wherein the rotor slot exhibits an axial extent which is at least as large as and preferably larger than the axial extent of the rotor plus the axial extent of the at least one sealing element.

13. The rotary pump according to claim 11, wherein the rotor slot exhibits an axial fitting extent which is at least as large as the axial extent of the rotor plus a maximum axial clearance of the drive shaft.

14. The rotary pump according to claim 11, wherein the sealing element is formed as an axial extension of the delivery element support, which extends axially out of the delivery space into the housing part.

15. A pump unit for a motor vehicle, comprising: a first rotary pump featuring a delivery space in which at least one rotor is arranged which delivers a fluid from an inlet into the delivery space on a low-pressure side of the first rotary pump to an outlet from the delivery space on a high-pressure side of the first rotary pump; a second rotary pump according to claim 1, featuring a delivery space in which at least one rotor is arranged which delivers a fluid from an inlet into the delivery space on a low-pressure side of the second rotary pump to an outlet from the delivery space on a high-pressure side of the second rotary pump; and a drive shaft for driving the rotary pumps, wherein the rotor of the first rotary pump and the rotor of the second rotary pump are connected, secured against axially shifting, to the drive shaft.

16. The rotary pump according to claim 1, wherein the rotary pump is a vacuum pump.

17. The rotary pump according to claim 8, wherein the axial extent of the bearing region is larger than the sum of the axial extents of the radial sealing gaps.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Aspects of the invention will now be described in more detail on the basis of figures. Features essential to aspects of the invention which can only be gathered from the figures form part of the scope of aspects of the invention and can advantageously develop the subject-matter of the invention, alone and/or in combinations shown.

[0044] The individual figures show:

[0045] FIG. 1 a pump unit featuring a liquid pump and a gas pump in a first sectional view;

[0046] FIG. 2 an enlarged detail of a region of the gas pump from FIG. 1;

[0047] FIG. 3 a pump unit featuring a liquid pump and a gas pump in a second sectional view;

[0048] FIG. 4 an enlarged detail of a region of the gas pump from FIG. 3;

[0049] FIG. 5 a drive shaft of the pump unit, featuring a delivery element support for accommodating delivery elements of the liquid pump and a delivery element support of the gas pump in which a delivery element is arranged such that it can be shifted, wherein the housing of the gas pump is shown in section;

[0050] FIG. 6 an enlarged detail of the drive shaft together with the rotor of the gas pump of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

[0051] FIG. 1 shows a longitudinal section through an example embodiment of a pump unit in accordance with the invention. The pump unit comprises a first rotary pump 1, which is formed as a liquid delivery pump, and a second rotary pump 2 which is formed as a vacuum pump. The pump unit can be referred to as a tandem pump. The pump unit is provided for a motor vehicle, wherein the first rotary pump 1 is used for lubricating an internal combustion engine of the motor vehicle, and the second rotary pump 2 is used for providing a vacuum for a brake servo of the motor vehicle.

[0052] The rotary pump 1 comprises a delivery space 11 in which a rotor 12 is arranged. The rotary pump 2 comprises a delivery space 21 in which a rotor 22 is arranged. The rotor 12 and the rotor 22 are connected in drive terms to a common, continuous drive shaft 3. The rotors 12, 22 are rotary-driven by the drive shaft 3.

[0053] The rotor 12 is arranged completely within the delivery space 11. The rotor 12 comprises a delivery element support 6 and multiple delivery elements which are accommodated by the delivery element support 6 such that they can be radially shifted. In order to accommodate the delivery elements such that they can be shifted, the delivery element support 6 comprises multiple rotor slots. The delivery element support 6 is connected, secured against rotating and shifting, to the drive shaft 3. The delivery element support 6 is pressed onto the drive shaft 3. The delivery elements are formed as vanes. The first rotary pump 1 is formed as a vane cell pump.

[0054] The rotor 22 is arranged completely within the delivery space 21. The rotor 22 comprises a delivery element support 5 and a delivery element 4 which is accommodated by the delivery element support 5 such that it can be radially shifted. In order to accommodate the delivery element 4 such that it can be shifted, the delivery element support 5 comprises a rotor slot 32 which is clearly shown in FIGS. 3 to 6 and will be described in detail. The rotor slot 32 extends axially into the drive shaft 3. The delivery element support 5 is connected, secured against rotating and shifting, to the drive shaft 3. The delivery element support 5 is formed integrally with the drive shaft 3. The drive shaft 3 integrally forms the delivery element support 5. The delivery element 4 is formed as a vane. The second rotary pump 2 is formed as a vane cell pump.

[0055] The rotor 12, 22 and an inner circumferential wall of the respective delivery space 11, 21 together form delivery cells in which the fluid, be it a liquid or gas, is transported from an inlet into the delivery space 11, 21 to an outlet from said delivery space 11, 21 and can be compressed and/or raised to a higher pressure level in the process if the rotor 12, 22 is arranged eccentrically in the delivery space 11, 21.

[0056] The rotary pumps 1, 2 comprise a common pump housing. The pump housing comprises the housing parts 13, 14, 23, 24. The two housing parts 13, 23 are combined in one housing part. They are formed by a single housing part. The housing part 24 forms a base of the delivery space 21 of the second rotary pump 2 featuring a central opening through which the drive shaft 3 can be connected to a drive (not shown). The housing part 24 seals an axial end-facing side of the delivery space 21 on the side facing away from the first rotary pump 1. The delivery space 21 is sealed on the end-facing side facing the first rotary pump 1 by the housing part 23 which simultaneously forms the housing part 13 for an axial end-facing side of the delivery space 11 of the first rotary pump 1 and comprises an opening through which the drive shaft 3 extends from the delivery space 21 into the delivery space 11. The second axial end-facing side of the delivery space 11 is sealed by the housing part 14.

[0057] The drive shaft 3 is mounted in the pump housing by means of three axially spaced slide bearings. The drive shaft 3 comprises three axially spaced bearing regions 7, 8, 9. The drive shaft 3 is mounted in a sliding manner in the bearing region 9 in the housing part 14, in the bearing region 7 in the combined housing part 13, 23, and in the bearing region 8 in the housing part 24. The outer circumferential surface of the drive shaft 3 and the inner circumferential surfaces of the housing parts 14, 13, 23, 24 radially opposite it form a bearing gap G.sub.B in the bearing regions 7, 8, 9. The delivery space 11 of the first rotary pump 1 is arranged axially between the bearing region 9 and the bearing region 7. The delivery space 21 of the second rotary pump 2 is arranged axially between the bearing region 7 and the bearing region 8.

[0058] The second rotary pump 2 comprises two axially spaced sealing elements 26, 27 which extend outside the delivery space 21 into immersion pockets 28, 29 which are incorporated into the housing part 24 and into the housing part 23. The delivery space 21 is arranged axially between the sealing elements 26, 27. The sealing element 26 is arranged axially between the bearing region 7 and the delivery space 21. The sealing element 27 is arranged axially between the bearing region 8 and the delivery space 21.

[0059] The radial outer surfaces of the sealing elements 26, 27, and radial circumferential surfaces of the immersion pockets 28, 29, together form a radial sealing gap G.sub.S which is sufficiently large in the radial direction that the sealing elements 26, 27 are not radially and/or axially guided in the immersion pockets 28, 29. The radial sealing gap G.sub.S is larger or has a larger radial extent than the bearing gap G.sub.B. The immersion pockets 28, 29 each exhibit an outer diameter which is larger than an outer diameter of the delivery element support 5 of the rotor 22.

[0060] FIG. 1 includes a circled-in portion X which is shown in an enlargement in FIG. 2. FIG. 2 shows the portion X of FIG. 1 which shows a detail of the second rotary pump 2 featuring: the delivery space 21; the delivery element support 5 formed by the drive shaft 3; the delivery element 4; the housing part 24; the housing part 23; and the drive shaft 3. An immersion pocket 28, 29, which is open towards the delivery space 21 and into which the sealing elements 26, 27 extend is formed in each of the housing part 23 and the housing part 24.

[0061] The sealing elements 26, 27 are formed in one piece with the delivery element support 5 of the rotor 22 and the drive shaft 3. They radially seal the delivery space 21 off. The sealing elements 26, 27 exhibit the same outer diameter as the delivery element support 5. The sealing elements 26, 27 are formed as or by axial extensions of the delivery element support 5 which extend axially out of the delivery space 21 into the immersion pockets 28, 29, wherein the extensions exhibit an outer diameter which is larger than an outer diameter of the drive shaft 3. The extensions extend into the housing parts 23, 24 which axially delineate the delivery space 21.

[0062] An axial extent of the sealing elements 26, 27 is smaller than the axial extent or depth of the immersion pockets 28, 29, such that it is possible to compensate for an axial clearance of the drive shaft 3 using the sealing elements 26, 27. The difference in length in the axial direction between the axial depth of the immersion pockets 28, 29 and the axial extent of the sealing elements 26, 27 is preferably larger than a maximum axial clearance of the drive shaft 3. An axial extent of the radial sealing gap G.sub.S is substantially smaller than an axial extent of the radial bearing gap G.sub.B.

[0063] The radial sealing gap G.sub.S can be supplied with fluid via a leakage flow which flows along the drive shaft 3 from the first delivery space 11 to the immersion pocket 28, 29. Alternatively, the immersion pockets 28, 29 can be supplied with fluid via a channel (not shown) which emerges into the immersion pocket 28, 29. The fluid forms a barrier in the radial sealing gap G.sub.S and thus prevents fluidin this case, gasfrom being able to escape from the delivery space 21.

[0064] FIG. 3 shows another longitudinal section through the pump unit, which as compared to FIG. 1 shows the pump unit in a view which is rotated by a quarter turn or 90 with respect to a longitudinal axis L or rotary axis of the drive shaft 3. The region of the second rotary pump 2 is indicated in FIG. 3 by a circular detail Y. The detail Y can be seen in a magnified view in FIG. 4.

[0065] FIG. 3 shows the, same as FIG. 1, but from a different angle of view. The first rotary pump 1, the second rotary pump 2 and the drive shaft 3 can be seen. The rotor slot 32 is formed in the drive shaft 3 in the region of the delivery element support 5 of the second rotary pump 2 which the drive shaft 3 participates in forming, wherein the delivery element 4 can move in the rotor slot 32 transverse to the longitudinal axis L in order to form, together with an inner circumferential wall 25 of the delivery space 21, delivery cells using which the fluid can be delivered from an inlet into the delivery space 21 to an outlet from the delivery space 21. An immersion pocket 28, 29 is incorporated in each of the housing parts 24 and 23 of the second rotary pump 2. A sealing element 26, 27 extends into each of the immersion pockets 28, 29 and radially seals the delivery space 21 off in the region of the transition from the rotor 22 into the housing part 23 and housing part 24. Because the sealing element 26, 27 is dimensioned to be smaller in the axial direction than the immersion pocket 28, 29, an axial gap G.sub.A is formed between the axial end-facing side of the sealing element 26, 27 which faces away from the rotor 22 and the base surface of the immersion pocket 28, 29 which faces the rotor 22. The immersion pockets 28, 29 in conjunction with the sealing elements 26, 27 thus together form a compensation device using which production tolerances in the axial direction, which can for example be introduced into the pump unit when pressing-on the delivery element support 6 of the first rotary pump 1, can be compensated for.

[0066] FIG. 4 shows a magnified view of a region of FIG. 3 which includes in particular the rotor slot 32. The rotor slot 32 exhibits an axial extent L.sub.RS and extends axially through the delivery element support 5 of the rotor 22, through the two sealing elements 26, 27, up to and into the drive shaft 3. The rotor slot 32 extends axially into the bearing regions 7, 8. The axial extent or axial length L.sub.RS of the rotor slot 32 shown is larger than the sum of the axial extent or axial length L.sub.R of the rotor 22 plus the axial extent L.sub.V of the two sealing elements 26, 27. Another extent which is specified is the axial fitting extent or fitting length L.sub.F which is smaller than the axial length L.sub.RS of the rotor slot 32 but larger than the axial length L.sub.R of the rotor 22. The axial fitting length L.sub.F refers to the region of the rotor slot 32 in which the delivery element 4 can move transverse to the longitudinal axis L of the rotary pump 2 without hindrance, i.e. without for example jamming, and in which the delivery element 4 is not pressed against one of the housing parts 23, 24 when the rotor slot 32 is shifted in the direction of the longitudinal axis L, for example in order to compensate for an axial clearance of the drive shaft 3.

[0067] A circumferential groove 31 is also formed in the drive shaft 3. The circumferential groove 31 is connected to the corresponding immersion pocket 28, 29 and the corresponding bearing region 7, 8. The groove 31 is also connected to the rotor slot 32. The rotor slot 32 extends into the circumferential groove 31. In the example embodiment, the groove 31 is divided in two and emerges into the rotor slot 32. Fluid from the immersion pocket 28, 29 and the bearing region 7, 8 can thus enter the rotor slot 32, where the fluid can for example serve to lubricate the delivery element 4 and to seal the delivery cells in the delivery space.

[0068] The circumferential groove 31 can in particular be seen in FIGS. 5 and 6. FIG. 5 shows the drive shaft 3 of the pump unit in a non-sectional view. FIG. 5 also shows the housing parts 23, 24 in a sectional view. FIG. 6 shows the detail Z from FIG. 5 in an enlargement.