HIGH-VOLTAGE MOTOR PUMP UNIT

Description

[0001] The invention relates to a hydraulic motor pump unit for pressurising a hydraulic fluid in a hydraulic circuit.

[0002] In particular, the hydraulic motor pump unit is provided with a crescent gear pump. Such a crescent gear pump is suitable to be used in an appliance in which the motor pump unit is continuously in operation, i.e. for at least 10minutes, and in which the motor pump unit operates under high pressures, i.e. of about 150bar.

[0003] More in particular, the hydraulic motor pump unit is configured to be used in a stabiliser system installed on a vehicle. More particularly to be used in such a stabiliser system in which roll restraining force exerted by a stabiliser bar is changeable by an operation of an actuator which is operable connected to the hydraulic motor pump unit.

[0004] JP-A-2002-518245 discloses an active stabiliser system in which an actuator having an electric motor is a drive source is arranged such that roll restraining force to be exerted by a stabiliser bar is changeable by controlling an operation of the actuator. The electric motor as the drive source is controlled via a driver such as an inverter.

[0005] The document JP 2020 056336 discloses an electrically driven pump which housing end cover provides cooling fins.

[0006] A problem to known hydraulic motor pump units is often that it has a poor heat dissipation. Many known hydraulic motor pump unit are typically suitable to be used incidentally, e.g. to actuate a transmission starting motor. In a continuous operation under a high pressure of at least 100bars, these known hydraulic motor pump units are vulnerable to get overheated. In particular, under a high voltage of 400V or even 800V, a large amount of heat will be generated by the coils which heat will drastically shorten a possible operational duration and will make these hydraulic pump units unsuitable to be used in a continuous operation under high pressure, e.g. in an active roll stabilisation system.

[0007] In particular, it is another object to provide a hydraulic motor pump unit having a compact structure in combination with a high pump effectiveness provided by the internal crescent gear pump. The compact structure allows the hydraulic motor pump unit to be installed at a narrow building space.

[0008] Regarding the above-mentioned prior art, it is remarked that any discussion of documents, acts, materials, devices, articles or the like included in the present specification is for the purpose of providing a context for the present invention, and is not to be taken as an admission that any such matters form part of the prior art or were before the priority date of each claim of this application common general knowledge in the field relevant to the present invention.

[0009] The general object of the present invention is to at least partially eliminate the above mentioned drawbacks and / or to provide a usable alternative. More specific, it is an object of the invention to provide a hydraulic motor pump unit having a compact configuration in which a crescent pump gear and an electric drive are integrally housed in which the motor pump unit is provided with a an effective cooling to prevent overheating of the motor pump unit in a continuous operation under a high pressure.

[0010] According to a first aspect of the invention, this object is achieved by a hydraulic motor pump unit according to claim 1.

[0011] In the first aspect, a hydraulic motor pump unit for pressurising a hydraulic fluid in a hydraulic circuit is provided. The hydraulic motor pump unit comprises: a motor having a motor stator holding a circular array of coils and a motor rotor having a motor rotor body having an outer circumferential rotor surface holding a circular array of magnets, in which the motor rotor body is positioned within the motor stator holding the magnets opposite the coils; a pump drivable connected to the motor rotor; and a housing having a housing body provided with a pump chamber for housing the pump and a cylindrically shaped coil support for supporting the circular array of coils; wherein the housing comprises at least one housing end cap which is connected to the coil support which housing end cap is provided with a fin pattern for an air cooling of the housing to an environment.

[0012] The hydraulic motor pump unit according to the first aspect of the invention is beneficial in that it may perform for a continuous duration of at least 10 minutes, in particular of at least 20 minutes under a high pressure of at least 100bar, in particular at least 150bar, in providing a flow of at least 15liters / minute, in particular at least 20liters / minute. The motor pump unit has a compact configuration. The presence of the fin pattern at one or both housing end caps is beneficial in providing an air cooling. Herewith, a dry concept of the motor pump unit is provided.

[0013] In an embodiment according to the invention, the housing has a front housing end cap and a rear housing end cap which are each provided with a fin pattern, wherein the coil support is sandwiched in between the front and rear housing end cap. Herewith, the motor pump unit has a beneficial compact configuration and includes a proper air cooling.

[0014] In an embodiment according to the invention, at least a portion of 50%, in particular at least 70%, more in particular at least 90% of an end face surface of the housing end cap is covered by the fin pattern.

[0015] In an embodiment according to the invention, the at least one housing end cap is integrally shaped with the housing body.

[0016] In an embodiment according to the invention, the at least one housing end cap is provided with an outlet port and an inlet port in fluid communication with the pump chamber, wherein the inlet port and the outlet port are positioned at a central region of the end face of the housing end cap.

[0017] In an embodiment according to the invention, at least one of the outlet port and inlet port is fluidly connected to the pump chamber by respectively a pressure line for pressurising an actuator and a return line for returning hydraulic fluid to the pump chamber, wherein the pressure line and / or return line extends along a cooling path through the housing end cap to provide liquid cooling to the housing end cap.

[0018] In a further embodiment according to the invention, the return line originating from the inlet port extends across the housing end cap along the cooling flow path for cooling the housing end cap, wherein with respect to the pressure line, the return line extends along a significant longer cooling path length, in particular at least 3 times longer, through the housing.

[0019] In an embodiment according to the invention, the cooling path extends across at least 60%, in particular at least 80% of a cross sectional region of the housing end cap.

[0020] In an embodiment according to the invention, the housing body has a central passage for receiving the motor rotor body, wherein the central passage is provided with a first and second bearing for journaling the motor rotor body, wherein the pump chamber is positioned in between the first and second bearing.

[0021] In an embodiment according to the invention, the first and / or second bearing are a plain bearing allowing a lubricating through flow of hydraulic fluid originating from the pump chamber to an opposite side of the respective first and / or second bearing.

[0022] In an embodiment according to the invention, the lubricating through flow at the second plain bearing is passed to the return line to return the lubricating through flow back to the pump chamber.

[0023] In an embodiment according to the invention, the motor is a brushless motor, in particular a brushless DC motor, more in particular a high voltage brushless DC motor. Advantageously, the brushless motor may further contribute to a compactness of the motor pump unit.

[0024] In an embodiment according to the invention, the coils of the motor have an electrical connection at the rear housing end cap, wherein the pressure line and return line only extend through the front housing end cap. This may further contribute to a compactness of the motor pump unit.

[0025] In an embodiment according to the invention, the pump is a gear pump, in particular an internal gear pump. Preferably, the gear pump is a crescent gear pump including a crescent member. The crescent member is positioned inside an outer gear wheel aside an inner gear wheel. In particular, the inner gear wheel is driven by the motor rotor, in which the inner gear wheel is connected to the motor rotor, in particular to a motor rotor shaft.

[0026] In an embodiment of the motor pump unit according to the invention, the gear pump is a bidirectional pump, or a so-called reversible pump. The gear pump has a first and second port which depending on a rotational direction of the driving motor serve as a suction port or pressure port. The first and second port are in fluid communication with the first pump chamber by a first and second line which in dependence of the rotational direction of the driving motor serve as a pressure or return line.

[0027] In an embodiment according to the invention, motor rotor body comprises a rotor shaft which has a centrally positioned inner rotor shaft channel along an axial axis in fluid communication with the inlet port.

[0028] In a further embodiment according to the invention, the rotor shaft channel extends from the first bearing beyond the second bearing for allowing a flow of hydraulic fluid back to the inlet port.

[0029] In an embodiment according to the invention, the rotor shaft is at a distal end connected to a rotor flange and a cylindrically shaped magnet holder.

[0030] In a further embodiment according to the invention, the rotor flange and magnet holder are incorporated in a one-piece item.

[0031] In an embodiment according to the invention, the motor rotor body is connected to an angular decoder for determining a rotational position of the motor rotor body.

[0032] Further, in the first aspect, the invention relates to a vehicle comprising a hydraulic motor pump unit according to the invention. In particular, the invention relates to a vehicle sub-assembly comprising a motor pump unit according to the invention wherein the vehicle sub-assembly is arranged to be continuously operated, in particular for at least 10minutes, under a high pressure, in particular of at least 100bar. More in particular, the invention relates to a vehicle active roll stabilisation system including a stabiliser bar to be positioned in between a left and right wheel suspension and a hydraulic actuator connected to the stabiliser bar, wherein the hydraulic actuator is controlled by a control unit and actuated by a motor pump unit according to the invention.

[0033] The invention will be explained in more detail with reference to the appended drawings. The drawings show a practical embodiment according to the invention, which may not be interpreted as limiting the scope of the invention. Specific features may also be considered apart from the shown embodiment and may be taken into account in a broader context as a delimiting feature, not only for the shown embodiment but as a common feature for all embodiments falling within the scope of the appended claims, in which: Fig. 1 shows a frontal perspective view of an embodiment of a motor pump unit according to a first aspect of the invention; Fig. 2 shows a rear perspective view of the motor pump unit of Fig. 1; Fig. 3 shows a top view of the motor pump unit of Fig. 2; Fig. 4 shows a cross sectional view on line IV IV in Fig. 3; Fig. 5 shows a cross-sectional view online V-V in Fig. 4; Fig. 6 shows an enlarged view of a left side of Fig. 5; Fig. 7 shows an enlarged view of a right side of Fig. 5.

[0034] In the figures 1-7, the motor pump unit is denoted overall by reference numeral 1. Identical reference signs are used in the drawings to indicate identical or functionally similar components. To facilitate comprehension of the description and of the claims the words longitudinal, axial, frontal, proximal, rear and distal are used in a non-limiting way.

[0035] Fig. 1 shows a hydraulic motor pump unit 1 according to a first aspect of the invention. The hydraulic motor pump unit is configured to pressurise a hydraulic fluid in a hydraulic circuit. In particular, the motor pump unit 1 is configured to pressurise a vehicle stabiliser system including a stabiliser bar. More in particular, the motor pump unit 1 is configured to pressurise a vehicle roll stabilisation system.

[0036] The motor pump unit comprises a motor 2 for driving a pump 3 inside a housing 4.

[0037] The motor 2 has a motor stator 20 including a circular array of coils 22 and a motor rotor 24 having a motor rotor body 25. The motor rotor body 25 has an outer circumferential rotor surface which holds a circular array of magnets 29. The magnets 29 are embedded in the outer circumferential rotor surface and held by a magnet holder 28. The motor rotor body 25 is positioned within the motor stator 20, such that the magnets 29 are positioned opposite the coils 22.

[0038] The pump 3 is driveable connected to the motor rotor 24. The pump comprises an internal gear pump 30. The internal gear pump is positioned inside a pump chamber 410 of the housing 4.

[0039] The internal gear pump 30 comprises an inner gear wheel 31 and an outer gear wheel 32. Here, the inner gear wheel 31 is drivable connected to the motor rotor 24. The inner gear wheel 31 is connected to a proximal end of a rotor shaft 26. At a distal end, the rotor shaft 26 is connected to a rotor flange 27 which rotor flange is at an outer circumference connected to the magnet holder 28.

[0040] A pressure line 33 and a return line 34 extend in between the pump chamber 410 and respectively an outlet port 35 and inlet port 36 at an outer surface of the housing 4. The return line 34 forms a cooling path 37. Externally originating hydraulic fluid enters the motor pump unit via the inlet port 36 and flows along the cooling path 37 to the pump chamber 410. The cooling path 37 extends through a major portion of the housing to contribute to a cooling of the housing.

[0041] The housing 4 has a centrally positioned housing body 41 which is provided with the pump chamber 410 for receiving the pump 3. Here, the housing body 41 is formed by a first housing portion 411 and a second housing portion 412.

[0042] Further, the housing 4 has a cylindrically shaped coil support 42 for supporting the circular array of coils 22. The coil support 42 is formed by a stack of ring-shaped members in an axial direction. At an inner side of the stack, the array of coils 22 is wound. At an outer side, the coil support 42 is surrounded by a casing 48.

[0043] The housing 4 comprises at least one housing end cap 43. Preferably, the housing end cap 43 is made of an aluminium material. Here, the housing 4 comprises a front housing end cap 43 and a rear housing end cap 44. The coil support 42 is sandwiched in between the front and rear housing end cap 43, 44. At least one of the housing end caps 43, 44 is provided with a fin pattern 45. Preferably, both housing end caps are finned. The fin pattern 45 is designed to provide an air cooling of the housing to an environment. Herewith, a dry concept of the motor pump unit MPU is provided. The dry concept MPU includes an air cooling. Heat generated by the coils 22 at the coil support 42 is conducted to the housing end cap 43 and dissipated to the environment by the fin pattern 45.

[0044] As shown in fig. 1, the fin pattern 45 covers more than 50% of an end face surface of the housing end cap. In particular, the fin pattern 45 covers more than 70% of the end face surface, more in particular the fin pattern covers more than 90% of the end face surface. Here, the fin pattern 45 has a cross-shape fin pattern in which fins are directed in perpendicular directions. Preferably, both the front and the rear housing end caps 43, 44 are provided with a fin pattern 45.

[0045] As shown in fig. 1, at a central region, the housing end cap 43 is provided with an outlet port 35 and an inlet port 36. The outlet port and inlet port are side by side positioned at a central region of the housing and 43.

[0046] Preferably, the housing end cap 43 is integrally shaped with the housing body 41, in particular integrally shaped with the first housing portion 411. The inlet port 36 is in fluid communication with the pump chamber 410 via a return line 34. The outlet port 35 is in fluid communication with the pump chamber 410 via a pressure line 33. Preferably, at least one of the return line 34 and pressure line 33 is used for cooling the housing 4. Instead of a direct fluid connection with the pump chamber, the return line 34 and / or the pressure line 33 extends along a cooling path 37 along a certain distance through the housing 4. In particular, the cooling path 37 extends across at least 60%, in particular at least 80% of a cross-sectional region of the housing end cap. The cooling path may extend from an outer diameter to an inner diameter of the housing end cap. The cooling path 37 may for example extend spirally through the housing end cap. Herewith, the housing end cap is cooled by a hydraulic fluid flow. Both the pressure and return line 33, 34 can be used for a liquid cooling of the housing end cap.

[0047] Preferably, the return line 34 is configured for a liquid cooling of the housing end cap 43. With respect to the pressure line 35, the return line 34 may extend along a significant longer cooling path length through the housing 4. In particular, the cooling path length of the return line 34 is at least three times longer than the path length of the pressure line 35. More in particular, the cooling path length of the return line 34 is at least 10 times longer than the path length of the pressure line 35. Hydraulic fluid which is supplied to the housing 4 from the outside may be cooled by the environment before flowing through the inlet port 36.

[0048] As shown in fig. 4, the housing body 41 has a central passage for receiving the motor rotor body 25, in particular a rotor shaft 26 of the motor rotor body 25. A first and second bearing 46, 47 are positioned in the central passage for journalling the motor rotor body. The first and second bearing are each a plain bearing. The plain bearing allows a lubricating through flow of hydraulic fluid originating from the pump chamber to flow to an opposite side of the respective first and / or second bearing.

[0049] As shown in fig. 5 and 6, the rotor shaft 26 is provided with a rotor shaft channel 260. The rotor shaft channel 260 extends axially from a proximal end of the rotor shaft 26 along the first and second bearing 46, 47 and is fluidly connected to a channel branch 261 which is in fluid communication with an inner space outside the pump chamber. Hydraulic fluid can flow from behind the second bearing through the rotor shaft channel 260 and a housing channel 430 back into the return line 36.

[0050] The motor pump unit 1 comprises a brushless motor, in particular a brushless DC motor, more in particular a high voltage DC motor. The brushless motor is in particular an 800V or 400V DC motor. As shown in the figures, an electrical connection 23 is provided at a rear side of the motor pump unit. The electrical connection 23 is positioned at the rear housing end cap 44. The electrical connection 23 is positioned at an end face of the motor pump unit opposite an end face provided with the inlet port and outlet port 35, 36. Here, the pressure line and return line 33, 34 only extend through the front housing end cap 43.

[0051] Thus, the invention provides a hydraulic motor pump unit 1 for pressurising a hydraulic fluid in a hydraulic circuit. The motor pump unit comprises a motor 2 having a motor stator holding a circular array of coils and a motor rotor having a motor rotor body having an outer circumferential rotor surface holding a circular array of magnets. The motor rotor body is positioned within the motor stator holding the magnets opposite the coils. A pump 3 is drivable connected to the motor rotor. A housing body 41 provided with a pump chamber 410 for housing the pump and a cylindrically shaped coil support 42 for supporting the circular array of coils. The housing comprises at least one housing end cap 43 which is connected to the coil support 42 which housing end cap is provided with a fin pattern 45 for an air cooling of the housing to an environment.

[0052] Although the present invention has been described in detail, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention as hereinafter claimed. It is intended that all such changes and modifications be encompassed within the scope of the present disclosure as claimed in the appended claims. Reference signs list Fig. 1-7:A-Aaxial axis31inner gear wheel1motor pump unit32outer gear wheel33 pressure line2motor34return line3pump35outlet port4housing36inlet port37cooling path20motor stator22coil4housing23connector; electrical connection41housing body24motor rotor410pump chamber25motor rotor body411first housing portion26rotor shaft412second housing portion260rotor shaft channel42coil support261channel branch43front housing end cap27rotor flange430channel28magnet holder44rear housing end cap29magnet45fin pattern46first bearing; first plain bearing30internal gear pump47second bearing; second plain bearing48casing50decoder

Claims

1. Hydraulic motor pump unit (1) for pressurising a hydraulic fluid in a hydraulic circuit, wherein the motor pump unit comprises: - a motor (2) having a motor stator holding a circular array of coils and a motor rotor having a motor rotor body having an outer circumferential rotor surface holding a circular array of magnets, in which the motor rotor body is positioned within the motor stator holding the magnets opposite the coils; - a pump (3) drivable connected to the motor rotor; and - a housing (4) having a housing body (41) provided with a pump chamber (410) for housing the pump and a cylindrically shaped coil support (42) for supporting the circular array of coils; wherein the housing comprises at least one housing end cap (43) which is connected to the coil support (42) which housing end cap is provided with a fin pattern (45) for an air cooling of the housing to an environment, wherein at least one of an outlet port and inlet port is fluidly connected to the pump chamber by respectively a pressure line for pressurising an actuator and a return line for returning hydraulic fluid to the pump chamber, wherein the pressure line and / or return line extends along a cooling path through the housing end cap to provide liquid cooling to the housing end cap.

2. Motor pump unit (1) according to claim 1, wherein the return line originating from the inlet port extends across the housing end cap along the cooling flow path for cooling the housing end cap, wherein with respect to the pressure line (35), the return line (34) extends along a significant longer cooling path length, in particular at least 3 times longer, through the housing.

3. Motor pump unit (1) according to claim 1 or 2, wherein the cooling path extends across at least 60%, in particular at least 80% of a cross sectional region of the housing end cap.

4. Motor pump unit (1) according to any of the preceding claims, wherein the housing has a front housing end cap (43) and a rear housing end cap (44) which are each provided with a fin pattern, wherein the coil support (42) is sandwiched in between the front and rear housing end cap.

5. Motor pump unit (1) according to any of the preceding claims, wherein at least a portion of 50%, in particular at least 70%, more in particular at least 90% of an end face surface of the housing end cap is covered by the fin pattern.

6. Motor pump unit (1) according to any of the preceding claims, wherein the at least one housing end cap (43) is integrally shaped with the housing body (41).

7. Motor pump unit (1) according to any of the preceding claims, wherein the at least one housing end cap (43) is provided with an outlet port (35) and an inlet port (36) in fluid communication with the pump chamber (410), wherein the inlet port and the outlet port are positioned at a central region of the end face of the housing end cap (43)8. Motor pump unit (1) according to any of the preceding claims, wherein the housing body (41) has a central passage for receiving the motor rotor body (25), wherein the central passage is provided with a first and second bearing (46, 47) for journaling the motor rotor body, wherein the pump chamber (410) is positioned in between the first and second bearing (46, 47, wherein in particular the first and / or second bearing are a plain bearing allowing a lubricating through flow of hydraulic fluid originating from the pump chamber (410) to an opposite side of the respective first and / or second bearing, wherein in particular the lubricating through flow at the second plain bearing (47) is passed to the return line (34) to return the lubricating through flow back to the pump chamber (410).

9. Motor pump unit (1) according to any of the preceding claims, wherein the motor (2) is a brushless motor, in particular a brushless DC motor, more in particular a high voltage brushless DC motor, wherein in particular the coils of the motor have an electrical connection (23) at the rear housing end cap, wherein the pressure line and return line only extend through the front housing end cap (43).

10. Motor pump unit (1) according to any of the preceding claims, wherein the pump is a gear pump, in particular an internal gear pump.

11. Motor pump unit (1) according to any of the preceding claims, wherein motor rotor body (25) comprises a rotor shaft (26) which has a centrally positioned inner rotor shaft channel (260) along an axial axis in fluid communication with the inlet port (36), wherein in particular the rotor shaft channel (260) extends from the first bearing (46) beyond the second bearing (47) for allowing a flow of hydraulic fluid back to the inlet port (36), wherein in particular the rotor shaft (26) is at a distal end connected to a rotor flange (27) and a cylindrically shaped magnet holder (28), wherein more in particular the rotor flange and magnet holder are incorporated in a one-piece item.

12. Motor pump unit (1) according to any of the preceding claims, wherein the motor rotor body (25) is connected to an angular decoder (50) for determining a rotational position of the motor rotor body.

13. Vehicle sub-assembly comprising a hydraulic motor pump unit according to any of the claims 1-12, wherein the vehicle sub-assembly is arranged to be continuously active during a ride for at least 10minutes in which the hydraulic motor pump unit is then operable under a high pressure of at least 100bars for actuating a hydraulic actuator, wherein in particular the vehicle sub-assembly is a vehicle active roll stabilisation system including a stabiliser bar to be positioned in between a left and right wheel suspension and including a hydraulic actuator connected to the stabiliser bar, wherein the hydraulic actuator is controlled by a control unit and actuated by the motor pump unit (1).

14. Vehicle comprising a hydraulic motor pump unit according to any of the claims 1- 12 and / or a vehicle sub-assembly according to claim 13.