Electric drive axle oil cooling system

Abstract

An electric drive axle oil cooling system comprises a motor module, a transmission module and a hub reduction gear module, the motor module, the transmission module and the hub reduction gear module are each provided with a circulating cooling oil way, and oil of the circulating cooling oil way of the hub reduction gear module is independently arranged. Oil inlets of the circulating cooling oil ways of the motor module and the transmission module are independently arranged, and oil return of the circulating cooling oil ways of the motor module and the transmission module is shared. Oil of the hub reduction gear module is independent in the whole process, the motor module cooling system and the reduction gear cooling system are relatively independent, the cleanliness of a motor is optimized, the service life of the motor is prolonged, and the efficiency of an electric drive system is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of drive axle cooling, and particularly relates to an oil cooling system for an electric drive axle. Background Art

[0002] An electric drive axle includes a motor module, a transmission module, and a wheel side reducer module. The cooling requirements mainly involve the stator and rotor of the motor module, the gear shafts of the transmission module, and the gear shafts of the wheel side reducer module. The cooling effect directly affects the temperature rise, efficiency, torque output, and service life of each module. Currently, the cooling methods for electric drive axles are a combination of oil cooling and water cooling or pure oil cooling.

[0003] For example, a cooling system for a new energy vehicle with a dual-motor drive system disclosed in CN118953001A. The dual-motor drive system includes a first motor, a second motor, and a gearbox oil tank. The cooling system is used for heat exchange with the first motor, the second motor, and the gearbox oil tank. The cooling system includes a first motor cooling system, a second motor cooling system, a first heat exchanger, and a second heat exchanger. The first motor cooling system is used to cool the coolant circulation of the first motor. The inlet of the first motor cooling system is connected to the coolant outlets of the first motor and the second motor, and the outlet is connected to the coolant inlet of the first motor. The second motor oil cooling system is used to cool the coolant circulation of the second motor. The inlet of the second motor oil cooling system is connected to the coolant outlets of the second motor and the first motor, and the outlet is connected to the coolant inlet of the second motor. The first heat exchanger is used to heat the oil in the gearbox oil tank and is connected to the first motor cooling system and the second motor oil cooling system, so that the high-temperature coolant transported by the first motor cooling system enters the coolant inlet of the second motor after being cooled by the second motor oil cooling system. The second heat exchanger is used to heat the oil in the gearbox oil tank and is connected to the second motor oil cooling system and the first motor cooling system, so that the high-temperature coolant transported by the second motor oil cooling system enters the coolant inlet of the first motor after being cooled by the first motor cooling system. In this application, the motor cooling and the transmission cooling oil are used in common, which will cause problems such as poor cleanliness of the cooling oil and difficult layout of the cooling pipelines. Summary of the Invention

[0004] Aiming at the problems existing in the above background art introduction, the purpose of the present invention is to provide an oil cooling system for an electric drive axle. Each module is cooled by a pure oil cooling method, and the cooling oil of the motor, transmission, and wheel side reducer is separated to improve the cleanliness of the oil in each module. Then, the housing opening at the filter of the oil storage cavity is opened to facilitate later maintenance and replacement. The oil flow is controlled by an independent oil pipe and an integrated oil passage in the housing to meet the cooling requirements of each module to the greatest extent.

[0005] The technical solution adopted by the present invention is as follows:

[0006] An oil cooling system for an electric drive axle, comprising a motor module, a transmission module, and a wheel side reducer module. The motor module, the transmission module, and the wheel side reducer module are all provided with a circulating cooling oil circuit. The oil in the circulating cooling oil circuit of the wheel side reducer module is independently arranged. The oil inlets of the circulating cooling oil circuits of the motor module and the transmission module are independently arranged, and the oil returns of the circulating cooling oil circuits of the motor module and the transmission module are shared.

[0007] Furthermore, the circulating cooling oil circuits of the motor module and the transmission module both include an oil pump. The input end of the oil pump is communicated with an oil storage cavity through a suction filter. A pressure filter is arranged at the output end of the oil pump. The output end of the pressure filter is communicated with a heat exchanger. The oil outlet end of the heat exchanger enters the motor rotor, the motor stator or the wheel side reducer through a through oil pipe respectively. The cooling oil circuit in the motor rotor is communicated with the cooling oil circuit in the motor stator. The outlet of the cooling oil circuit in the motor stator and the outlet of the cooling oil circuit in the wheel side reducer are both communicated with the corresponding oil storage cavity.

[0008] Furthermore, an opening structure is arranged at the installation position of the suction filter, which is convenient for replacing the suction filter.

[0009] Furthermore, end covers are arranged at both ends of the motor stator. A spray cooling oil circuit for spraying the stator winding is arranged in the end cover. The spray cooling oil circuit is communicated with the through oil pipe through an oil inlet on the end cover. An oil discharge hole communicated with the oil storage cavity is arranged at the bottom of the end cover.

[0010] Furthermore, the spray cooling oil circuit is a semi-circular structure.

[0011] Furthermore, an annular oil circuit for spraying the stator core is arranged on the stator core of the motor stator.

[0012] Furthermore, the motor rotor has a hollow motor shaft. The hollow oil passage in the motor shaft is communicated with the through oil pipe. An oil throwing hole is arranged on the motor shaft. The cooling oil thrown out by the oil throwing hole can be thrown into the end cover of the motor stator through an inclined oil throwing groove on the motor rotor.

[0013] Furthermore, a water pipe for taking away the internal oil temperature is connected to the outside of the heat exchanger.

[0014] The beneficial effects of the present invention:

[0015] 1. The oil in the wheel side reducer module is separate throughout the process. The cooling system of the motor module is relatively independent of the cooling system of the reducer, optimizing the cleanliness of the motor itself, increasing the service life of the motor, and improving the efficiency of the electric drive system.

[0016] 2. The unique design of the internal cooling pipeline in the motor module enables the oil to be sprayed onto the motor stator and rotor as much as possible, so that more heat of the motor can be taken away by the oil, and the cooling effect is better.

[0017] 3. The front part of the cooling systems of the motor and the transmission is shared, which can save the internal space of the box body and reduce the overall cost.

[0018] 4. The shell opening at the suction filter is processed for regular replacement of the filter for maintenance. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of the present invention.

[0020] Figure 2 is a schematic diagram of the internal setting structure of the motor module of the present invention.

[0021] Figure 3 is a schematic diagram of the installation position structure of the suction filter of the present invention.

[0022] Figure 4 is a schematic cross-sectional view of the motor stator end cover of the present invention.

[0023] In the figure: 1. Motor module; 2. Transmission module; 3. Wheel side reducer module; 4. Suction filter; 5. Oil pump; 6. Pressure filter; 7. Heat exchanger; 8. Motor rotor; 9. Motor stator; 10. Oil pipe; 11. Spray cooling oil circuit. Detailed Embodiments

[0024] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternative solutions, improvement solutions and equivalent solutions that may be included within the scope of the claims.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more, unless otherwise clearly defined.

[0026] In the present invention, unless otherwise clearly specified and defined, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0028] See Figures 1-4 , this embodiment provides an oil cooling system for an electric drive axle, including a motor module 1, a transmission module 2, and a wheel side reducer module 3. The motor module 1, the transmission module 2, and the wheel side reducer module 3 are all provided with a circulating cooling oil circuit. The oil in the circulating cooling oil circuit of the wheel side reducer module 3 is independently arranged. The inlet oil of the circulating cooling oil circuits of the motor module 1 and the transmission module 2 is independently arranged, and the return oil of the circulating cooling oil circuits of the motor module 1 and the transmission module 2 is commonly arranged. The common arrangement of the return oil means that it flows back to the same oil storage cavity.

[0029] The circulating cooling oil circuit of the motor module 1 in this embodiment includes an oil pump 5. The input end of the oil pump 5 is communicated with the corresponding oil storage cavity through a suction filter 4. A pressure filter 6 is arranged at the output end of the oil pump 5. The output end of the pressure filter 6 is communicated with a heat exchanger 7. The oil outlet end of the heat exchanger 7 enters the motor rotor 8 and the motor stator 9 respectively through a connecting oil pipe 10. The cooling oil circuit in the motor rotor 8 is communicated with the cooling oil circuit in the motor stator 9. The cooling oil circuit outlet in the motor stator 8 is communicated with the corresponding oil storage cavity. The cooling of the motor module 1 of the present invention separately applies a filter for suction filtration, an oil pump, a second filter for pressure filtration, and a heat exchanger, so as to ensure the cleanliness of the motor cooling oil. Specifically, end covers are arranged at both ends of the motor stator 9. A spray cooling oil circuit 11 for spraying the stator winding is arranged in the end covers. The spray cooling oil circuit 11 is communicated with the connecting oil pipe through an oil inlet on the end cover. An oil discharge hole communicated with the oil storage cavity is arranged at the bottom of the end cover. The spray cooling oil circuit 11 is of a semi-circular structure. A surrounding oil circuit for spraying the stator core is arranged on the stator core of the motor stator 9. The motor rotor 8 has a hollow motor shaft. The hollow oil passage in the motor shaft is communicated with the connecting oil pipe. Oil throwing holes are arranged on the motor shaft. The cooling oil thrown out of the oil throwing holes can be thrown into the end cover of the motor stator through an inclined oil throwing groove on the motor rotor. An opening structure is arranged at the installation position of the suction filter 4, which is convenient for replacing the suction filter 4. A water pipe for taking away the internal oil temperature is connected to the outside of the heat exchanger 7. The present invention does not provide a motor housing, which optimizes the motor structure. Moreover, the motor module is separately provided with an oil inlet and an oil discharge hole, and the relevant axial channels are sealed with oil seals or sealants, reducing pipeline layout and saving occupied space. For the cooling of the motor rotor 8, the oil comes out from the heat exchanger 4 and is directly connected to the motor shaft through a pipeline for forced cooling. Oil holes are attached to the motor shaft and the dynamic balance plate of the motor rotor 8. The oil is thrown into the periphery of the motor rotor through the rotation of the motor shaft, that is, into the end cover 6 of the motor stator.

[0030] The working principle of the cooling system of the motor module 1 of the present invention is as follows: The oil is first filtered by the suction filter 4 to remove impurities, then sucked out by the oil pump 5, and then finely filtered again by the pressure filter 6, and then flows to the heat exchanger 7 for cooling (a water pipe is connected to the outside of the heat exchanger, and the internal oil temperature is taken away by the water circuit to achieve the cooling effect). After the oil comes out from the heat exchanger 7, it flows to the motor stator 9 and the motor rotor 8 through the connecting oil pipe 10, so as to realize the oil cooling of the motor.

[0031] The wheel side reducer module 3 in this embodiment circulates the oil independently, and an appropriate amount of oil is injected into the cavity. The oil is thrown to relevant parts according to the rotation of the internal shaft teeth to achieve the cooling effect, and its internal cavity is not mixed with the oil of the motor module and the transmission module.

[0032] The oil of the in-wheel reducer module of the present invention is separate throughout the process. The cooling system of the motor module is relatively independent of the cooling system of the reducer, optimizing the cleanliness of the motor itself, increasing the motor life, and improving the efficiency of the electric drive system. The unique design of the internal cooling pipeline in the motor module enables the oil to be sprayed onto the motor stator and rotor as much as possible, so that more heat of the motor is carried away by the oil, and the cooling effect is better. The front part of the cooling systems of the motor and the transmission is shared, which can save the internal space of the box body and reduce the overall cost. The housing opening at the suction filter is processed for regular replacement of the filter for maintenance.

Claims

1. An oil cooling system for an electric drive axle, comprising a motor module, a transmission module, and a wheel-side reducer module, wherein the motor module, the transmission module, and the wheel-side reducer module are all provided with a circulating cooling oil circuit, characterized in that: The oil in the circulating cooling oil circuit of the wheel-side reducer module is independently set, the oil inlet of the circulating cooling oil circuit of the motor module and the transmission module is independently set, and the oil return of the circulating cooling oil circuit of the motor module and the transmission module is shared.

2. The electric drive axle oil cooling system according to claim 1, characterized in that: The circulating cooling oil circuits of the motor module and the transmission module both include an oil pump. The input end of the oil pump is connected to the oil storage chamber through a suction filter. The output end of the oil pump is provided with a pressure filter. The output end of the pressure filter is connected to the heat exchanger. The oil outlet end of the heat exchanger enters the motor rotor, the motor stator or the wheel-side reducer through an oil pipe. The cooling oil circuit in the motor rotor is connected to the cooling oil circuit in the motor stator. The cooling oil circuit outlet in the motor stator and the cooling oil circuit outlet in the wheel-side reducer are both connected to the corresponding oil storage chamber.

3. The electric drive axle oil cooling system according to claim 2, characterized in that: An opening structure is provided at the installation position of the suction filter.

4. The electric drive axle oil cooling system according to claim 2, characterized in that: End covers are provided at both ends of the motor stator, and a spray cooling oil circuit for spraying the stator winding is provided inside the end cover. The spray cooling oil circuit is connected to the oil pipe through the oil inlet on the end cover, and an oil drain hole connected to the oil storage cavity is provided at the bottom of the end cover.

5. The electric drive axle oil cooling system according to claim 4, characterized in that: The spray cooling oil circuit is a semicircular structure.

6. The electric drive axle oil cooling system according to claim 2, characterized in that: The stator core of the motor stator is provided with an embracing oil circuit for spraying the stator core.

7. The electric drive axle oil cooling system according to claim 2, characterized in that: The motor rotor has a hollow motor shaft, the hollow oil passage in the motor shaft is connected to the oil pipe, and the motor shaft is provided with an oil throwing hole, and the cooling oil thrown out of the oil throwing hole can be thrown into the end cover of the motor stator through the oblique oil throwing groove on the motor rotor.

8. The electric drive axle oil cooling system according to claim 2, characterized in that: The outside of the heat exchanger is connected with a water pipe that takes away the internal oil temperature.

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