OIL PUMP CONFIGURATION FOR A MOTOR VEHICLE

Abstract

An oil pump configuration for a motor vehicle includes an oil pump having a pump part and an electric pump motor, wherein the pump part is operatively connected to the electric pump motor, The pump part and/or the electric pump motor can be mounted to a housing which at least partially delimits an oil chamber. Sealing problems at the pump part are prevented and the required installation space is low because the pump part can be mounted inside the housing and the electric pump motor can be mounted from the outside to the housing.

Claims

1. An oil pump configuration for a motor vehicle transmission, comprising: an oil pump having a pump part and an electric pump motor, said pump part being operatively connected to said electric pump motor; and a housing, said housing at least partially delimiting an oil chamber, said pump part being mountable inside said housing, said electric pump motor being mountable on said housing from outside.

2. The oil pump configuration according to claim 1, wherein: said housing has a receiver; and said electric pump motor engages at least partially in said receiver.

3. The oil pump configuration according to claim 2, wherein: said housing has a mounting wall delimiting said receiver; said mounting wall is formed with a passage opening; and said pump part is centered on an inner side of said mounting wall and said electric pump motor is centered on an outer side of said mounting wall.

4. The oil pump configuration according to claim 1, wherein: a control unit is disposed on said electric pump motor; and said control unit is sealed against said electric pump motor.

5. The oil pump configuration according to claim 4, wherein: said housing has a receiver; said electric pump motor engages at least partially in said receiver; and said control unit is sealed against said receiver by at least a seal.

6. The oil pump configuration according to claim 1, wherein said oil pump is disposed at a differential gear of the motor vehicle transmission.

7. The oil pump configuration according to claim 1, including: an intermediate shaft disposed in an articulated manner; and said pump part and said electric pump motor being joined to one another via said intermediate shaft.

8. The oil pump configuration according to claim 1, wherein said pump part is bolted to said housing such that said pump part performs a reinforcing function for said housing.

9. The oil pump configuration according to claim 1, wherein said housing has a rib, said rib is formed with a cutout at said pump part, wherein said pump part bridges said cutout.

10. The oil pump configuration according to claim 1, including a main oil pump functionally actively driven by an internal combustion engine, said main oil pump being provided parallel to said oil pump in a hydraulic oil circuit.

11. The oil pump configuration according to claim 1, including a switchover valve provided downstream of said oil pump, wherein in one switch position of said switchover valve, said oil pump feeds a mechatronic unit and in another switch position of said switchover valve, said oil pump feeds a cooling oil branch.

12. The oil pump configuration according to claim 1, wherein said oil pump has an electrical power supply which is independent of a transmission control device.

13. The oil pump configuration according to claim 10, wherein an intake tract of said main oil pump can be charged by said oil pump.

14. The oil pump configuration according to claim 1, wherein said housing is configured as a clutch housing.

15. The oil pump configuration according to claim 14, wherein said clutch housing forms a part of a transmission casing and at least partially seals said transmission casing.

16. The oil pump configuration according to claim 14, wherein said clutch housing least partially seals a transmission casing.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0043] FIG. 1 is a diagrammatic cross-sectional view of an additional oil pump disposed on a clutch housing and an axle differential gear in accordance with the invention;

[0044] FIG. 2 is a diagrammatic, cross-sectional detailed view of the additional oil pump according to the invention;

[0045] FIG. 3 is a highly schematic view of a motor vehicle with an internal combustion engine and a dual clutch transmission in accordance with the invention;

[0046] FIG. 4 is a diagrammatic view of a first hydraulic circuit with the additional oil pump and a main oil pump in accordance with the invention; and

[0047] FIG. 5 is a highly diagrammatic view of a further hydraulic circuit with the main oil pump and the additional oil pump according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0048] Referring now to the figures of the drawing in detail and first, particularly, to FIGS. 1 and 2 thereof, there is shown an oil pump configuration 1 with an additional oil pump 2 for a transmission (not shown in detail) of a motor vehicle.

[0049] The additional oil pump 2 is integrated in a hydraulic circuit 26 or 27 (see FIG. 4 or 5), wherein the hydraulic circuits 26, 27 each include a main oil pump 28, wherein the main oil pump 28 is provided in parallel to the additional oil pump 2 (with the corresponding pump part 3 and pump motor 4). The pump part 3 is in particular configured as a gear pump. The pump part 3 may be configured as a gerotor pump, i.e. an annular gear pump, or as a crescent pump.

[0050] Before discussing the hydraulic circuits 26, 27 in detail, firstly the arrangement and configuration of the additional oil pump 2 will be explained with reference to FIG. 1 and FIG. 2.

[0051] The additional oil pump 2 has a hydrostatic pump part 3 and a pump motor 4. The pump part 3 can be driven by the pump motor 4 and is operatively connected to the pump motor 4. The pump part 3 and the pump motor 4 are mounted on a housing 5. The housing 5 is configured in particular as a clutch housing 6. The housing 5 delimits, i.e. bounds, an oil chamber 7.

[0052] The disadvantages cited initially are now avoided in that the pump part 3 can be mounted inside the housing 5, and the pump motor 4 can be mounted on the housing 5 from the outside. The housing 5 has a receiver (receptacle) 8. The pump part 3 is mounted from the inside on the housing 5, and the pump motor 4 with a control unit 9 is mounted from the outside in the receiver 8 on the housing 5. The drive unit is formed of the pump motor 4 and the control unit 9 and is arranged so as to be accessible from the outside for customer service and hence replaceable.

[0053] The housing 5 has a mounting wall 10. The mounting wall 10 has a seat 11 protruding into the receiver. The pump motor 4 is centered on the seat 11. The seat 11 surrounds a passage opening 12. Furthermore, on the other side of the mounting wall 10, in the interior, the pump part 3 is centered on the passage opening 12. The seat 11 and the passage opening 12 are formed centrally on the mounting wall 10. The passage opening 12 is in particular formed cylindrical and extends coaxially to a virtual pump axis (not shown) of the additional oil pump 2. The passage opening 12 and the seat 11 allow a common centering of the pump part 3 and the pump motor 4.

[0054] The mounting wall 10 has openings 37 so that oil can enter the receiver 8. The receiver 8 therefore also forms part of the oil chamber 7. The pump motor 4 is situated inside the oil chamber 7. A gap 36 remains between the pump motor 4 and the receiver 8. Through this gap, the pump motor 4 can be cooled by the corresponding oil (not shown) on the outer periphery.

[0055] An intermediate shaft 13 is provided (see FIG. 2), wherein the intermediate shaft 13 connects the pump part 3 and the pump motor 4 to one another through the passage opening 12. The intermediate shaft 13 is integrated captively in the pump part 3. The power is transmitted between the pump motor 4 and the pump part 3 via splines or a polygonal profile (not shown in detail) or alternatively via another form-locking connection. The intermediate shaft 13 is preferably not mounted fixedly and may therefore compensate for angular defects or angle errors between the pump motor 4 and the pump part 3 in the manner of a cardan shaft.

[0056] The control unit 9 is arranged on the head 14 of the pump motor 4. The control unit 9 is in particular connected to the pump motor 4. Preferably, a screw connection 15 is provided (see FIG. 1) which connects the control unit 9 to the pump motor 4. The control unit 9, in particular a corresponding housing (not shown in detail) of the control unit 9, is now used to seal the receiver 8 of the clutch housing 6 against the environment. For this, the control unit 9 protrudes at least partially into the receiver 8 and lies sealing against the inner periphery of the receiver 8 through the use of corresponding seals 16. The control unit 9—in contrast to the pump motor 4—lies partially outside the clutch housing 6. The seals 16 could in particular be formed as O-rings. Alternatively, shaped sealing rings or a multi-lip seal could be used as seals 16 in order to seal the control unit 9 against the receiver 8. Furthermore, a drive-internal oil seal is provided to seal the control unit 9 against the pump motor 4 around which oil flows. For this, in particular electrically conductive three-phase lines are sealed by a potting compound or sealing compound from the pump motor 4. In particular, the compound may be a glass potting or glass sealing compound.

[0057] As clearly evident from FIG. 1, the additional oil pump 2 is here arranged in the region of a differential gear 17. The differential gear 17 has in particular two axle shafts 18, 19 which are operatively connected via corresponding differential pinions 20. The differential pinions 20 are mounted correspondingly rotatably on a driven differential housing 21. The pump part 3 and the pump motor 4 are arranged in or on the clutch housing 6 in the vicinity of the differential gear 17. The axis of this system, including the pump part 3 and the pump motor 4, lies below the middle of the differential gear 17, as close as possible to the suction filter (not shown). This system axis is planar-parallel to the corresponding axis of the axle shafts 18, 19. However, a totally different orientation of the axis of the additional oil pump 2 is possible.

[0058] The installation space of the pump part 3 intersects with supporting structures, namely a corresponding rib formed on the inside of the clutch housing 6. The pump part 3 preferably has a supporting function and transmits corresponding loads without leading to a deformation in the gear set (not shown in detail) of the pump part 3. The housing 5 has a rib (not shown in detail), wherein the rib has a cutout in the region of the pump part 3, wherein the pump part 3 bridges the cutout and thus performs the reinforcement function of the rib in this region. The pump part 3 has a pump housing 38. The pump housing 38 is configured such that the necessary supporting function of the rib is performed by the pump housing 38. The structure is selected such that the loads to be transferred lead at most to slight deformations in the pump housing 38, namely of the corresponding gear set. The pump housing 38 is connected via three bolts to the clutch housing 6. The hydraulic part of the additional oil pump 2—namely the pump part 3—is integrated in the transmission chamber so as to be inaccessible from the outside.

[0059] The control unit 9 is formed in particular curved or “banana-shaped”, and thus surrounds in arcuate fashion the region of the differential gear 17 shown on the right in FIG. 1. The control unit 9 is here arranged in the region of the interface for the front axle drive or front axle transverse differential lock. When these assemblies are installed, the control unit 9 is arranged between the housing 22 of the front axle drive and the housing 5. In all-wheel drive vehicles or vehicles with transverse differential lock, no excessive heating occurs. If these ancillary assemblies are not fitted, the control unit 9 could be exposed to the heat of the exhaust system. The heat is therefore dissipated from the control unit 9 via solid bolting to the clutch housing 6, or alternatively via a superficial contact or surface contact of the control unit 9 with the clutch housing 6. This electrically driven additional oil pump 2 can be integrated in the existing installation space in a dual clutch transmission DKG installed transversely (see FIG. 3). With a maximum power consumption of the additional oil pump 2 of 300 Watt, in particular cooling oil quantities of up to 15 liters per minute can be provided.

[0060] FIG. 3 shows an internal combustion engine VKM and a dual clutch transmission DKG. The dual clutch transmission DKG is controlled or regulated by a transmission control unit GSG. The transmission control unit GSG is connected to an engine control unit MSG via a drive CAN bus (CAN=controller area network). The transmission control unit GSG is connected to the pump control unit 9/PSG via a transmission CAN bus. The pump control unit 9/PSG is connected to a power or voltage source 23. This voltage source 23 can, as shown, work with 12 Volt or, in an alternative configuration, provide 48 Volt for example. The power supply 23 is independent of a power supply of the transmission control unit GSG. Thus for later applications, it is easily possible to convert the additional oil pump 2 from e.g. 12 Volt to 48 Volt, without having to change the transmission control unit GSG. The pump motor 4 is operated as an actuator of the transmission control unit GSG and supplied with control signals and setpoint quantities by the transmission CAN bus.

[0061] The additional oil pump 2 is not shown in detail in FIG. 3 but is here however arranged below the differential gear 17, wherein the two axle shafts 18, 19 depart from the differential gear 17 and drive the corresponding drive wheels 24, 25. The internal combustion engine VKM and the dual clutch transmission are installed transversely in the frontal region of the motor vehicle.

[0062] In the description which follows, the two hydraulic oil circuits 26, 27 are described with reference to FIGS. 4 and 5:

[0063] The hydraulic oil circuits 26, 27 firstly each have a main oil pump 28, wherein the respective main oil pump 28 is provided parallel to the additional oil pump 2 with the corresponding pump part 3 and pump motor 4. The main oil pump 28 and the additional oil pump 2 deliver corresponding transmission oil via a suction filter 29 from a transmission oil sump 30. The main oil pump 28 supplies a mechatronic unit 31. From the mechatronic unit 31, corresponding actuators 32 or also the clutch 33 are supplied with pressurized oil. Furthermore, via the mechatronic unit 31, cooling oil or lubricating oil is supplied to the transmission, as depicted by the two pinions on the left in FIGS. 4 and 5. The additional oil pump 2 now delivers corresponding oil to the mechatronic unit 31, in parallel to the main oil pump 28. A check valve 34 is provided between the mechatronic unit 31 and the additional oil pump 2. In one embodiment, the check valve 34 is arranged inside the housing 5. Alternatively, the check valve 34 may be integrated in the mechatronic unit 31.

[0064] Furthermore, a check valve 39 is provided downstream of the main oil pump 28. If only the additional oil pump 2 is delivering, and not the main oil pump 28, the check valve 39 blocks the delivery flow of the additional oil pump 2 against the main oil pump 28 so that the delivery flow is conducted to the mechatronic unit 31. The flow through the main oil pump 28 against the delivery direction is suppressed by the check valve 39. In one embodiment, the check valve 39 is arranged inside the housing 5. The check valve 39 may be integrated in the main oil pump 39. Alternatively, the check valve 39 may be integrated in the mechatronic unit 31.

[0065] In the embodiment shown in FIG. 5, the main oil pump 28 is adjustable. This ensures that, even at low rotation speeds of the internal combustion engine VKM, sufficient cooling oil is still available. In the embodiment shown in FIG. 4, the main oil pump 28 is configured as a constant pump. A valve 35 is now arranged downstream of the additional oil pump 2, between the additional oil pump 2 and the check valve 34. Through the use of this valve 35, it is possible to provide cooling oil below the main pressure. The valve 35 may be controlled via an electrical precontrol valve in the mechatronic unit 31. Alternatively, the valve 35 may be controlled directly. The valve 35 may be arranged inside the housing 5. In an alternative embodiment, the valve 35 may be integrated in the mechatronic unit 31. The main oil pump 28 is configured as a constant oil pump and has a large displacement volume. Thus an adequate oil supply is guaranteed in every operating situation.

[0066] In particular, the motor vehicle has a start-stop system. Since the main oil pump 28 does not deliver when the internal combustion engine is not running, the additional oil pump 2 is now provided. In this way, in particular a start-stop system is conceivable even at more than 2 km/h and coasting of the motor vehicle with the internal combustion engine VKM switched off. Due to the arrangement of the additional oil pump 2, the system is robust. Furthermore, due to the additional oil pump 2, even with longer stoppage times and a start-stop system, it is guaranteed that the system pressure can be built up sufficiently quickly. Furthermore, the additional oil pump 2 can increase the overall efficiency in the drive train. In particular, losses from the provision of hydraulic auxiliary energy for actuation and for cooling and lubricating purposes can be reduced. No additional hydraulic accumulator is integrated in the corresponding hydraulic circuits 26, 27. The main oil pump 28 may for example be designed smaller, since extreme situations can be compensated by powering of the additional oil pump 2. In particular, with the proposed additional oil pump 2, start-stop functionalities can be provided even at higher speeds of e.g. 7 km/h, or coasting of the motor vehicle with the internal combustion engine VKM switched off. Due to the additional oil pump 2, hydraulic energy in the form of a pressurized oil supply or lubricating oil supply can be provided even when the motor vehicle has stopped.

[0067] The main oil pump 28 may be configured as a vane pump. The additional oil pump 2 may now be used to compensate for intake difficulties of the vane pump or main oil pump 28. For example, the main oil pump 28 may be charged by the additional oil pump 2, wherein the mechatronic unit 31 is connected via an additional supply line 40 to the intake tract of the main oil pump 28. The supply line 40 preferably opens into a suction manifold (not shown) of the main oil pump 28. Preferably, the supply line 40 is switchable through the use of the mechatronic unit 31. Charging of the main oil pump 28 is thus ensured by the mechatronic unit 31. If no pressurized oil and no cooling oil volume flow are required, then apart from system leakages, the entire oil volume flow of the additional pump 2 flows via the additional supply line 40 into the intake tract of the main oil pump 28. When the intake tract of the main oil pump 28 is in the oil-filled state, no intake difficulties occur.

LIST OF REFERENCE CHARACTERS

[0068] 1 Oil pump configuration

[0069] 2 Additional oil pump

[0070] 3 Pump part

[0071] 4 Pump motor

[0072] 5 Housing

[0073] 6 Clutch housing

[0074] 7 Oil chamber

[0075] 8 Receiver

[0076] 9 Control unit

[0077] 10 Mounting wall

[0078] 11 Seat

[0079] 12 Passage opening

[0080] 13 Intermediate shaft

[0081] 14 Head

[0082] 15 Screw connection

[0083] 16 Seal

[0084] 17 Differential gear

[0085] 18 Axle shaft

[0086] 19 Axle shaft

[0087] 20 Differential pinion

[0088] 21 Differential housing

[0089] 22 Housing (front wheel axle drive)

[0090] 23 Power supply

[0091] 24 Drive wheel

[0092] 25 Drive wheel

[0093] 26 Hydraulic circuit

[0094] 27 Hydraulic circuit

[0095] 28 Main oil pump

[0096] 29 Suction filter

[0097] 30 Gear oil sump

[0098] 31 Mechatronic unit

[0099] 32 Actuator

[0100] 33 Clutch

[0101] 34 Check valve

[0102] 35 Valve

[0103] 36 Gap

[0104] 37 Openings

[0105] 38 Pump housing

[0106] 39 Check valve

[0107] 40 Supply line

[0108] VKM Internal combustion engine

[0109] DKG Dual clutch transmission

[0110] GSG Transmission control unit

[0111] PSG Pump control unit

[0112] MSG Engine control unit