Cooling system for electric drive assembly, electric drive assembly, vehicle and control method

Abstract

A cooling system for an electric drive assembly, being used for providing lubricating oil for the electric drive assembly. The electric drive assembly comprises an electric motor assembly and a variable-speed gear set, and the cooling system comprises a mechanical oil pump (10) and an electronic oil pump (20), the mechanical oil pump (10) being configured to be drivingly connected to the variable-speed gear set. The mechanical oil pump (10) can rotate along with the electric drive assembly to provide circulating power for cooling oil, and the electronic oil pump (20) is configured to provide circulating power for the cooling oil when the temperature of the cooling oil is higher than a first preset temperature and a vehicle speed is lower than a first preset vehicle speed. Further provided are an electric drive assembly, a vehicle, and a control method.

Description

Cooling system of electric drive assembly, electric drive assembly, vehicle and control method

[0001] This application claims priority to Chinese patent application No. 202311417909.2, filed on October 26, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of vehicle technology, and in particular to a cooling system for an electric drive assembly, an electric drive assembly, a vehicle, and a control method. Background Art

[0003] In related technologies, electric drive assemblies mostly use electronic oil pumps, which include a pump body and a drive component. In a low-temperature environment, the drive component is difficult to start. Technical issues

[0004] In view of this, embodiments of the present application hope to provide a cooling system for an electric drive assembly, an electric drive assembly, a vehicle, and a control method that are applicable to low-temperature environments. Technical Solutions

[0005] To achieve the above objectives, a first aspect of an embodiment of the present application provides a cooling system for an electric drive assembly, for providing lubricating oil to the electric drive assembly, wherein the electric drive assembly includes a motor assembly and a speed change gear set drivingly connected to the motor assembly, and the cooling system includes:

[0006] a mechanical oil pump, configured to be in driving connection with the speed change gear set; the mechanical oil pump can rotate along with the speed change gear set to provide cooling oil circulation power;

[0007] The electronic oil pump is used to provide cooling oil circulation power when the temperature of the motor component is higher than a first preset temperature and the vehicle speed is lower than a first preset speed.

[0008] In some embodiments, the mechanical oil pump is configured to be drivingly connected to an output gear of the speed change gear set.

[0009] In some embodiments, the cooling system includes a first circulation loop, and the mechanical oil pump and the electronic oil pump are provided in the first circulation loop;

[0010] The first circulation loop comprises:

[0011] a first cooling branch, for providing cooling oil to the stator of the motor assembly;

[0012] a second cooling branch, for providing cooling oil to the rotor of the motor assembly;

[0013] The third cooling branch is used to provide cooling oil to the bearings of the speed change gear set.

[0014] In some embodiments, the cooling system includes an electromagnetic proportional valve, which is used to adjust the flow ratio of the cooling oil flowing into the first cooling branch and the cooling oil flowing into the second cooling branch and the third cooling branch.

[0015] In some embodiments, the cooling system includes a thermostat and a heat exchange oil circuit having an oil-water heat exchanger, wherein the heat exchange oil circuit and the first circulation loop together constitute a second circulation loop, and in the second circulation loop, the heat exchange oil circuit is located between the first cooling branch, the second cooling branch, and the third cooling branch and the mechanical oil pump and the electronic oil pump;

[0016] The thermostat is arranged at the connection between the heat exchange oil circuit and the first circulation loop, and is used to control the heat exchange oil circuit to be connected to the first circulation loop to switch from the first circulation loop to the second circulation loop, or to control the heat exchange oil circuit to be disconnected from the first circulation loop to switch from the second circulation loop to the first circulation loop.

[0017] In some embodiments, the cooling system includes a water cooling circulation loop, and the oil-water heat exchanger is disposed in the water cooling circulation loop;

[0018] The water cooling circulation loop includes a controller heat sink, which is used to cool the controller of the electric drive assembly.

[0019] In some embodiments, the mechanical oil pump includes a mechanical pump body and four one-way valves;

[0020] The mechanical pump body is an internal gear pump, including a first oil inlet channel, a second oil inlet channel, a first oil outlet channel, a second oil outlet channel and an internal gear, and the four one-way valves are respectively provided in the first oil inlet channel, the second oil inlet channel, the first oil outlet channel and the second oil outlet channel;

[0021] The first ends of the first oil inlet channel and the second oil inlet channel are connected to the oil inlet hole of the mechanical pump body, the second end of the first oil inlet channel is connected to the positive rotation negative pressure side of the internal gear, and the second end of the second oil inlet channel is connected to the negative pressure side of the negative rotation of the internal gear;

[0022] The first ends of the first oil outlet channel and the second oil outlet channel are connected to the oil outlet hole of the mechanical pump body, the second end of the first oil outlet channel is connected to the forward high-pressure side of the internal gear, and the second end of the second oil outlet channel is connected to the reverse high-pressure side of the internal gear.

[0023] A second aspect of an embodiment of the present application provides an electric drive assembly, including:

[0024] a housing having a mounting cavity;

[0025] a motor assembly, disposed in the mounting cavity;

[0026] a speed-changing gear set, disposed in the mounting cavity and in transmission connection with the motor assembly; and

[0027] In the cooling system of any of the above embodiments, the mechanical oil pump is disposed in the installation cavity.

[0028] A third aspect of an embodiment of the present application provides a vehicle, comprising an electric drive assembly according to any one of the above embodiments, wherein the electric drive assembly is provided in two groups, one for the front drive of the vehicle and the other for the rear drive of the vehicle, and the two groups of the electric drive assemblies face in opposite directions.

[0029] A fourth aspect of the present application provides a control method for a cooling system, which is applicable to the cooling system of any of the above embodiments. The control method includes:

[0030] Obtaining the current temperature of the motor assembly;

[0031] Get the current vehicle speed;

[0032] comparing the current temperature with a first preset temperature;

[0033] If the current temperature is higher than the first preset temperature, comparing the current vehicle speed with the first preset vehicle speed;

[0034] If the current vehicle speed is lower than the first preset vehicle speed, the electronic oil pump is controlled to start.

[0035] In some embodiments, after the step of controlling the electronic oil pump to start if the current vehicle speed is lower than the first preset vehicle speed, the control method includes:

[0036] If the current vehicle speed is higher than a second preset vehicle speed, the electronic oil pump is controlled to be turned off, and the second preset vehicle speed is greater than or equal to the first preset vehicle speed.

[0037] In some embodiments, the first preset oil temperature is -30°C.

[0038] In some implementations, the first preset vehicle speed is in the range of 30-40 km / h.

[0039] A fifth aspect of the present application provides a method for controlling a cooling system, which is applicable to the cooling system. The method includes:

[0040] Get the current oil temperature;

[0041] If the current oil temperature is lower than a second preset temperature, adjusting the thermostat to enter the first circulation loop;

[0042] If the current oil temperature is greater than or equal to the second preset temperature, the thermostat is adjusted to enter the second circulation loop.

[0043] In some embodiments, the second preset oil temperature is 60°C. Beneficial effects

[0044] The cooling system, electric drive assembly, vehicle, and control method of the electric drive assembly of the embodiments of the present application are characterized by providing a mechanical oil pump that is transmission-connected to the speed gear set. When the electric drive assembly is started and the speed gear set begins to rotate, the mechanical oil pump follows the rotation and begins pumping oil. No additional drive member is required to drive the mechanical oil pump, and thus it can be used in low-temperature environments. Furthermore, when the temperature of the motor assembly is higher than a first preset temperature and the vehicle speed is lower than the first preset speed, that is, when the temperature of the motor assembly is too high and the oil supply of the mechanical oil pump is relatively low, the electronic oil pump provides cooling oil circulation power, which can increase the oil supply and thus meet the cooling requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a schematic structural diagram of an electric drive assembly cooling system according to an embodiment of the present application;

[0046] FIG2 is a cross-sectional view of a mechanical oil pump of an electric drive assembly cooling system according to an embodiment of the present application;

[0047] FIG3 is a schematic diagram of an oil circuit of a mechanical oil pump in a forward rotation state of an electric drive assembly cooling system according to an embodiment of the present application;

[0048] FIG4 is a schematic diagram of an oil circuit for a mechanical oil pump in reverse rotation in an electric drive assembly cooling system according to an embodiment of the present application;

[0049] FIG5 is a flow chart of a cooling system control method according to an embodiment of the present application.

[0050] Description of Reference Numerals

[0051] Mechanical oil pump 10; mechanical pump body 11; one-way valve 12; oil inlet hole 10a; oil outlet hole 10b; first oil inlet channel 11a; second oil inlet channel 11b; first oil outlet channel 11c; second oil outlet channel 11d; electronic oil pump 20; stator 211; rotor 212; first cooling branch 31; second cooling branch 32; third cooling branch 33; electromagnetic proportional valve 40; thermostat 50; heat exchange oil circuit 60; oil-water heat exchanger 61; water cooling circulation loop 70; water pump 71; cooler 72; controller heat sink 73; oil pan 221; controller 230; temperature sensor 240; bearing 251. Modes for Carrying Out the Invention

[0052] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0053] In the description of the embodiments of the present application, it should be noted that the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0054] In related technologies, electric drive assemblies mostly use electronic oil pumps, which include a pump body and a drive component. In a low-temperature environment, the viscosity of the oil is very high, and the drive component has difficulty starting.

[0055] Referring to Figure 1 , an embodiment of the present application provides a cooling system for an electric drive assembly, configured to provide lubricating oil to the electric drive assembly. The electric drive assembly includes a motor assembly and a speed-changing gear set. The motor assembly includes a stator 211 and a rotatable rotor 212 disposed within the stator 211. The speed-changing gear set is in driving connection with the motor assembly to transmit power from the motor assembly to the wheels.

[0056] The cooling system includes a mechanical oil pump 10 and an electronic oil pump 20. The mechanical oil pump 10 is a mechanical pump body structure. Since it has no power source, it requires external power to drive the oil pump. The electronic oil pump 20 includes a mechanical pump body and a drive member, which drives the mechanical pump body to pump oil.

[0057] The mechanical oil pump 10 is used for driving connection with the speed change gear set. The mechanical oil pump 10 can rotate with the electric drive assembly to provide cooling oil circulation power, that is, when the electric drive assembly is started, the mechanical oil pump 10 starts to follow and start to pump oil.

[0058] The electronic oil pump 20 is used to provide cooling oil circulation power when the cooling oil temperature is above a first preset temperature and the vehicle speed is below a first preset speed. A cooling oil temperature above the first preset temperature indicates a decrease in the cooling capacity of the cooling oil. A vehicle speed below the first preset speed indicates a relatively low speed of the transmission gear train. Since the speed is directly proportional to the oil supply of the mechanical oil pump 10, the oil supply of the mechanical oil pump 10 is also relatively low. Providing cooling oil circulation power through the electronic oil pump 20 can increase oil supply, thereby meeting cooling requirements.

[0059] In this embodiment, a mechanical oil pump 10 is provided so as to be connected to the transmission gear set. When the electric drive assembly is started and the transmission gear set begins to rotate, the mechanical oil pump 10 follows the rotation and begins to pump oil. No additional drive member is required to drive the mechanical oil pump 10 to work. Therefore, there is no problem of the electronic oil pump being unable to start due to the temperature being too low or the viscosity of the lubricating oil being too high. The embodiment is applicable to low temperature environments. In addition, when the temperature of the motor assembly is higher than the first preset temperature and the vehicle speed is lower than the first preset speed, that is, when the temperature of the motor assembly is too high and the oil supply of the mechanical oil pump 10 is relatively low, the electronic oil pump 20 provides cooling oil circulation power, which can increase the oil supply and thus meet the cooling demand.

[0060] Exemplarily, the mechanical oil pump 10 is configured to be drivingly connected to an output gear of a speed change gear set.

[0061] It can be understood that the output gear of the speed change gear set is used to drive the wheels to rotate, and the transmission connection with the output gear can make the pumping amount of the mechanical oil pump 10 positively correlated with stability.

[0062] Exemplarily, the cooling system includes a first circulation loop, and the mechanical oil pump 10 and the electronic oil pump 20 are provided in the first circulation loop, and the mechanical oil pump 10 and the electronic oil pump 20 provide cooling oil circulation power to the first circulation loop.

[0063] The first circulation loop includes a first cooling branch 31, a second cooling branch 32, and a third cooling branch 33. The first cooling branch 31 is used to provide cooling oil to the stator 211 of the electric drive assembly's motor assembly. The second cooling branch 32 is used to provide cooling oil to the rotor 212 of the electric drive assembly's motor assembly. The third cooling branch 33 is used to provide cooling oil to the bearings 251 of the speed change gear set of the electric drive assembly. This provides cooling oil to the stator 211, rotor 212 of the motor assembly, and the bearings 251 of the speed change gear set, thereby reducing the operating temperatures of all three.

[0064] It is understandable that the first cooling branch 31, the second cooling branch 32 and the third cooling branch 33 can be external pipes as connecting pieces between adjacent components, or can be channels formed in the housing of the electric drive assembly as connecting pieces between adjacent components.

[0065] It can be understood that the end of the first cooling branch 31 that provides cooling oil to the stator 211 of the motor assembly of the electric drive assembly may have multiple first branches, and cooling oil is provided to multiple different areas of the stator 211 through the multiple first branches, for example, cooling oil is provided to both ends of the stator 211 along the axial length.

[0066] The end of the second cooling branch 32 that provides cooling oil to the rotor 212 of the motor assembly of the electric drive assembly may have multiple second branches, through which cooling oil is provided to multiple different areas of the rotor 212, for example, cooling oil is provided to both ends of the rotor 212 along the axial length.

[0067] The end of the third cooling branch 33 that provides cooling oil to the bearing 251 of the speed change gear set of the electric drive assembly may have multiple third branches, and cooling oil is provided to the bearings 251 at both ends of the speed change gear set through multiple second branches.

[0068] Exemplarily, the cooling system includes an electromagnetic proportional valve 40 , which is used to adjust the flow ratio of the cooling oil flowing into the first cooling branch 31 and the flow ratio of the cooling oil flowing into the second cooling branch 32 and the third cooling branch 33 .

[0069] The solenoid proportional valve 40 is a hydraulic valve that proportionally converts an electrical input signal into force or displacement, thereby controlling flow. The proportional valve adjusts the flow ratio of cooling oil flowing into the first cooling branch 31, the second cooling branch 32, and the third cooling branch 33.

[0070] It should be noted that some vehicles have two electric drive assemblies, spaced apart along the vehicle's direction of travel and oriented in opposite directions. When one electric drive assembly rotates forward, the other rotates counterclockwise. Since lubrication of the transmission gear set's bearings 251 is achieved through the rotation of oil-guiding ribs on the gears, reverse gear rotation will cause a change in the amount of oil delivered. A proportional control valve can be provided to compensate for insufficient oil supply to the transmission gear set's bearings 251.

[0071] In some embodiments, the electromagnetic proportional valve 40 is disposed in the first cooling branch 31 , and the cooling oil flowing into the first cooling branch 31 flows toward the stator 211 of the motor assembly after passing through the electromagnetic proportional valve 40 .

[0072] It is understood that when the motor assembly is in a low-temperature environment, the demand for cooling oil is low or even no oil cooling is required. In this case, the solenoid proportional valve 40 can be used to reduce the amount of oil flowing into the first cooling branch 31 or even shut down the first cooling branch 31. In this case, the cooling system only supplies cooling oil to the second cooling branch 32 and the third cooling branch 33. This reduces the amount of oil supplied to the cooling system and lowers power consumption.

[0073] In some embodiments, the electromagnetic proportional valve 40 is disposed in the third cooling branch 33 to adjust the amount of bearing cooling oil flowing into the speed change gear set.

[0074] It is understood that when the vehicle is level or at a slight inclination, the splash lubrication within the reduction gearbox can meet the bearing lubrication requirements. Therefore, the third cooling branch 33 can be closed, thereby reducing the amount of oil delivered to the cooling system and lowering power consumption. When the vehicle is at a large longitudinal or lateral inclination, the solenoid proportional valve 40 is opened, allowing cooling oil to flow into the third cooling branch 33, actively lubricating and replenishing the bearings.

[0075] Illustratively, the cooling system includes a thermostat 50 and a heat exchange oil circuit 60 including an oil-water heat exchanger 61 .

[0076] The thermostat 50 has a temperature sensing component and can control the coolant flow path according to the temperature.

[0077] The oil-water heat exchanger 61 is used to cool the cooling oil in the heat exchange oil circuit 60. Specifically, the oil-water heat exchanger 61 is located in the water circulation path. Low-temperature water flows into the oil-water heat exchanger 61, absorbs heat from the cooling oil, and then flows back into the oil-water heat exchanger 61 after cooling down in the cooler.

[0078] The heat exchange oil circuit 60 and the first circulation loop together form a second circulation loop. That is, the cooling oil in the first circulation loop flows into the heat exchange oil circuit 60, is cooled by the oil-water heat exchanger 61, and then flows back into the first circulation loop to provide low-temperature cooling oil to the stator 211 and rotor 212 of the motor assembly, as well as the bearing 251 of the speed change gear set.

[0079] In the second circulation loop, the heat exchange oil circuit 60 is located between the first cooling branch 31, the second cooling branch 32, and the third cooling branch 33, and the mechanical oil pump 10 and the electronic oil pump 20. When the electronic oil pump 20 is turned on, cooling oil flows through the mechanical oil pump 10 and the electronic oil pump 20 into the heat exchange oil circuit 60. After being cooled by the oil-to-water heat exchanger 61 in the heat exchange oil circuit 60, it flows into the first cooling branch 31, the second cooling branch 32, and the third cooling branch 33, thereby cooling the stator 211 and rotor 212 of the motor assembly, as well as the bearing 251 of the speed change gear set.

[0080] The thermostat 50 is provided at the connection between the heat exchange oil circuit 60 and the first circulation loop, and is used to control the heat exchange oil circuit 60 to be connected to the first circulation loop to switch from the first circulation loop to the second circulation loop, or to control the heat exchange oil circuit 60 to be disconnected from the first circulation loop to switch from the second circulation loop to the first circulation loop.

[0081] Thermostat 50 controls whether the heat exchange oil circuit 60 is connected to or disconnected from the first circulation loop based on the oil temperature. For example, when the temperature is 60°C or higher, thermostat 50 connects the heat exchange oil circuit 60 to the first circulation loop, switching from the first circulation loop to the second circulation loop, thereby lowering the cooling oil temperature and improving the cooling effect. When the temperature is below 60°C, thermostat 50 disconnects the heat exchange oil circuit 60 from the first circulation loop, switching from the second circulation loop to the first circulation loop, thereby reducing energy consumption.

[0082] Illustratively, the cooling system includes a water cooling circulation loop 70 , and the oil-water heat exchanger 61 is disposed in the water cooling circulation loop 70 .

[0083] The water cooling circuit 70 includes a water pump 71 and a cooler 72. The water pump 71 is used to provide power for the water circulation. The cooler 72 is used to dissipate heat and cool the water to cool it down.

[0084] The water-cooling circuit 70 includes a controller heat sink 73, which is used to cool the controller of the electric drive assembly. Specifically, in this embodiment, the heat-releasing components of the water-cooling circuit 70 are the oil-water heat exchanger 61 and the controller heat sink 73. The heat-absorbing component is the cooler 72. The controller includes heat-generating components such as a control unit and a DC-DC converter.

[0085] An embodiment of the present application also provides an electric drive assembly, including a housing, a motor assembly, a speed change gear set, and a cooling system.

[0086] The housing has a mounting cavity, and the motor assembly is disposed within the mounting cavity. A speed change gear set is disposed within the mounting cavity and is in transmission connection with the motor assembly. Thus, the motor assembly can drive the speed change gear set to rotate, thereby driving the tire to rotate.

[0087] It is understandable that the housing includes an oil pan 221 having an oil storage cavity for storing cooling oil, and the oil inlet of the mechanical oil pump 10 and the oil inlet of the electronic oil pump 20 are in communication with the oil storage cavity.

[0088] The cooling system includes a mechanical oil pump 10, which is mounted within the housing. As the speed change gear train rotates, the mechanical oil pump 10 rotates with it, pumping oil. As will be appreciated, the housing reduces noise levels due to the mechanical oil pump 10 being located within the housing.

[0089] The electric drive assembly includes a controller 230 and a temperature sensor 240. Temperature sensor 240 is located in the first circulation loop, such as within the oil reservoir or mounting chamber, to detect oil temperature. Controller 230 controls the power output and cooling of the electric drive assembly, as well as the activation and deactivation of the electronic oil pump 20.

[0090] Illustratively, the mechanical oil pump 10 includes a mechanical pump body 11 and four one-way valves 12 .

[0091] The mechanical pump body 11 is an internal gear pump and includes a first oil inlet channel 11a, a second oil inlet channel 11b, a first oil outlet channel 11c, a second oil outlet channel 11d, and an internal gear. The internal gear is located between the first and second oil inlet channels 11a and 11b and the first and second oil outlet channels 11c and 11d.

[0092] Four one-way valves 12 are respectively provided in the first oil inlet channel 11a, the second oil inlet channel 11b, the first oil outlet channel 11c and the second oil outlet channel 11d. In other words, each of the first oil inlet channel 11a, the second oil inlet channel 11b, the first oil outlet channel 11c and the second oil outlet channel 11d is provided with a one-way valve 12.

[0093] The first ends of the first and second oil inlet channels 11a and 11b are connected to the oil inlet hole 10a of the mechanical pump body 11. The second end of the first oil inlet channel 11a is connected to the forward negative pressure side of the internal gear, while the second end of the second oil inlet channel 11b is connected to the reverse negative pressure side of the internal gear. The first ends of the first and second oil outlet channels 11c and 11d are connected to the oil outlet hole 10b of the mechanical pump body 11. The second end of the first oil outlet channel 11c is connected to the forward high pressure side of the internal gear, while the second end of the second oil outlet channel 11d is connected to the reverse high pressure side of the internal gear.

[0094] It is understood that the internal gear is driven by a speed-changing gear set. The internal gear has a forward negative-pressure side, a reverse negative-pressure side, a forward high-pressure side, and a reverse high-pressure side. The forward negative-pressure side is the oil-intake side of the internal gear during forward rotation. The reverse negative-pressure side is the oil-intake side of the internal gear during reverse rotation. The forward high-pressure side is the oil-discharge side of the internal gear during forward rotation. The reverse high-pressure side is the oil-discharge side of the internal gear during reverse rotation.

[0095] Referring to Figure 3, when the internal gear rotates forward, check valve 12 in first oil inlet channel 11a opens, check valve 12 in second oil inlet channel 11b closes, check valve 12 in first oil outlet channel 11c opens, and check valve 12 in second oil outlet channel 11d closes. Cooling oil from the oil inlet flows sequentially through first oil inlet channel 11a, the forward-rotating negative pressure side of the internal gear, the forward-rotating high pressure side of the internal gear, and first oil outlet channel 11c before exiting the oil outlet.

[0096] Referring to Figure 4, when the internal gear rotates in reverse, the one-way valve 12 in the first oil inlet channel 11a closes, the one-way valve 12 in the second oil inlet channel 11b opens, the one-way valve 12 in the first oil outlet channel 11c closes, and the one-way valve 12 in the second oil outlet channel 11d opens. The negative pressure side of the reverse rotation becomes the oil inlet side. Cooling oil from the oil inlet flows sequentially through the second oil inlet channel 11b, the negative pressure side of the internal gear, the high pressure side of the internal gear, and the second oil outlet channel 11d, before exiting the oil outlet.

[0097] In this way, the mechanical oil pump has the oil pumping function when the speed change gear set rotates forward and reverse.

[0098] It is understood that in some embodiments, the vehicle has two electric drive assemblies arranged in opposite directions, which serve as the front and rear drives of the vehicle respectively. When the vehicle performs a U-turn on the spot, both electric drive assemblies can supply fuel normally.

[0099] In some embodiments, the first oil inlet channel 11a and the second oil inlet channel 11b are arranged in parallel, and the first oil outlet channel 11c and the second oil outlet channel 11d are arranged in parallel.

[0100] In some embodiments, the central axes of the first oil inlet channel 11a and the second oil outlet channel 11d coincide with each other. The central axes of the second oil inlet channel 11b and the first oil inlet channel 11a coincide with each other.

[0101] The present application also provides a vehicle comprising an electric drive assembly, wherein two electric drive assemblies are provided, one for front driving the vehicle and the other for rear driving the vehicle. The two electric drive assemblies face opposite directions, i.e., the two electric drive assemblies are 180° opposite each other.

[0102] It's understandable that, since the two electric drive assemblies rotate in opposite directions, when one rotates forward, the other rotates counterclockwise. Since lubrication of the speed change gear set's bearings 251 is achieved through the rotation of the oil-guiding ribs on the gears, reverse gear rotation will cause a change in the amount of oil delivered, which can affect the lubrication of the speed change gear set's bearings 251. If the speed change gear set's bearings 251 are under-supplied with oil, adjusting the proportional control valve can compensate for the oil supply.

[0103] Referring to FIG5 , an embodiment of the present application further provides a control method for a cooling system, which is applicable to the cooling system. The control method includes:

[0104] S1. Get the current temperature of the motor assembly.

[0105] The current temperature of the motor assembly can be obtained by measuring the stator of the motor assembly or by measuring the cooling oil. Alternatively, a first value can be obtained by measuring the stator of the motor assembly and a second value can be obtained by measuring the cooling oil, and the higher of the first and second values ​​can be selected as the current temperature of the motor assembly. These measurements can be obtained by measuring with a temperature sensor.

[0106] S2. Get the current vehicle speed.

[0107] The current vehicle speed may be determined by calculating the rotational speed of the wheel and the diameter of the wheel, wherein the rotational speed of the wheel may be determined according to the rotational speed of the output gear of the speed change gear set.

[0108] S3. Compare the current temperature with the first preset temperature.

[0109] The first preset temperature is a preset value. In some embodiments, the first preset temperature is -30°C. It should be noted that at this temperature, the viscosity of the lubricating oil is relatively high.

[0110] S4. If the current temperature is higher than the first preset temperature, compare the current vehicle speed with the first preset vehicle speed.

[0111] It should be noted that the first preset vehicle speed may have different values ​​for different vehicle models. In some embodiments, the first preset vehicle speed is determined by obtaining the NVH (Noise, Vibration, Harshness) performance of the oil pump motor at different vehicle speeds on the corresponding vehicle model.

[0112] In some embodiments, the first preset vehicle speed is 30-40 km / h, wherein the first preset vehicle speed can be 30 km / h, 35 km / h or 40 km / h.

[0113] S5. If the current vehicle speed is lower than the first preset vehicle speed, the electronic oil pump 20 is controlled to start.

[0114] The order of step S1 and step S2 is not limited.

[0115] It is understandable that after step S3 , if the current temperature is lower than the first preset temperature, the electronic oil pump 20 is not started. At this time, the oil supply of the mechanical oil pump 10 can meet the cooling demand of the cooling system.

[0116] It is understandable that after step S4, if the current vehicle speed is higher than the first preset speed, the electronic oil pump 20 is not started. At this time, the oil supply of the mechanical oil pump 10 connected to the speed change gear set is large and can meet the cooling demand of the cooling system.

[0117] A mechanical oil pump 10 is provided, which is in transmission connection with the speed change gear set. When the electric drive assembly is activated and the speed change gear set begins to rotate, the mechanical oil pump 10 follows the rotation and begins pumping oil, eliminating the need for an additional driver to operate the mechanical oil pump 10. Furthermore, when the current temperature of the motor assembly is higher than a first preset temperature and the vehicle speed is lower than the first preset speed, that is, when the current temperature of the cooling oil motor assembly is too high and the oil supply of the mechanical oil pump 10 is relatively low, the electronic oil pump 20 provides cooling oil circulation power, thereby increasing the oil supply and meeting cooling requirements.

[0118] Exemplarily, after step S5, the control method includes:

[0119] S6. If the current vehicle speed is higher than the second preset vehicle speed, the electronic oil pump 20 is controlled to be turned off, and the second preset vehicle speed is greater than or equal to the first preset vehicle speed.

[0120] It is understandable that the greater the current vehicle speed, the greater the oil supply of the mechanical oil pump 10. When the vehicle speed is higher than the second preset speed, the oil supply of the mechanical oil pump 10 can meet the cooling demand, and the electronic oil pump 20 can be turned off to reduce energy consumption and noise.

[0121] It is understood that the second preset speed may vary depending on the vehicle type. In some embodiments, the second preset speed is 80-100 km / h. The second preset speed may be 80 km / h, 90 km / h, or 100 km / h.

[0122] The present application also provides a method for controlling a cooling system, the method comprising:

[0123] S10. Obtain the current oil temperature.

[0124] S20: If the current oil temperature is lower than the second preset temperature, adjust the thermostat 50 to switch to the first circulation loop.

[0125] In some embodiments, the second preset oil temperature is 60°C.

[0126] S30: If the current oil temperature is greater than or equal to the second preset temperature, adjust the thermostat 50 to switch to the second circulation loop.

[0127] The thermostat 50 controls whether the heat exchange oil circuit 60 is connected to or disconnected from the first circulation loop based on the oil temperature. When the temperature is 60°C or higher, the thermostat 50 connects the heat exchange oil circuit 60 to the first circulation loop, switching from the first circulation loop to the second circulation loop. This lowers the temperature of the cooling oil and improves the cooling effect. When the temperature is below 60°C, the thermostat 50 disconnects the heat exchange oil circuit 60 from the first circulation loop, switching from the second circulation loop to the first circulation loop, thereby reducing energy consumption.

[0128] In the description of this application, the description with reference to the terms "some embodiments", "exemplarily", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine different embodiments or examples described in this application and the features of different embodiments or examples without contradiction.

[0129] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A cooling system for an electric drive assembly, for providing lubricating oil to the electric drive assembly, wherein the electric drive assembly comprises a motor assembly and a speed change gear set drivingly connected to the motor assembly, wherein: The cooling system comprises: A mechanical oil pump, used for driving connection with the speed change gear set; the mechanical oil pump can rotate with the speed change gear set to provide cooling oil circulation power; The electronic oil pump is used to provide cooling oil circulation power when the temperature of the motor component is higher than a first preset temperature and the vehicle speed is lower than a first preset vehicle speed.

2. The cooling system according to claim 1, wherein: The mechanical oil pump is used for transmission connection with the output gear of the speed change gear set.

3. The cooling system according to claim 1, wherein: The cooling system comprises a first circulation loop, and the mechanical oil pump and the electronic oil pump are arranged in the first circulation loop; The first circulation loop comprises: a first cooling branch, for providing cooling oil to the stator of the motor assembly; a second cooling branch, for providing cooling oil to the rotor of the motor assembly; The third cooling branch is used to provide cooling oil to the bearings of the speed change gear set.

4. The cooling system according to claim 3, wherein: The cooling system includes an electromagnetic proportional valve, which is used to adjust the flow ratio of cooling oil flowing into the first cooling branch and the second cooling branch and the third cooling branch.

5. The cooling system according to claim 4, wherein: The electromagnetic proportional valve is arranged in the first cooling branch; or The electromagnetic proportional valve is arranged in the third cooling branch.

6. The cooling system according to claim 4, wherein: The cooling system includes a thermostat and a heat exchange oil circuit having an oil-water heat exchanger, wherein the heat exchange oil circuit and the first circulation circuit together constitute a second circulation circuit, and in the second circulation circuit, the heat exchange oil circuit is located between the first cooling branch, the second cooling branch, and the third cooling branch and the mechanical oil pump and the electronic oil pump; The thermostat is arranged at the connection between the heat exchange oil circuit and the first circulation loop, and is used to control the connection between the heat exchange oil circuit and the first circulation loop to switch from the first circulation loop to the second circulation loop, or to control the disconnection between the heat exchange oil circuit and the first circulation loop to switch from the second circulation loop to the first circulation loop.

7. The cooling system according to claim 6, wherein: The cooling system comprises a water cooling circulation loop, and the oil-water heat exchanger is arranged in the water cooling circulation loop; The water cooling circulation loop includes a controller heat sink, and the controller heat sink is used to cool the controller of the electric drive assembly.

8. The cooling system according to claim 1, wherein: The mechanical oil pump comprises a mechanical pump body and four one-way valves; The mechanical pump body is an internal gear pump, comprising a first oil inlet channel, a second oil inlet channel, a first oil outlet channel, a second oil outlet channel and an internal gear, and the four one-way valves are respectively arranged in the first oil inlet channel, the second oil inlet channel, the first oil outlet channel and the second oil outlet channel; The first ends of the first oil inlet passage and the second oil inlet passage are connected to the oil inlet hole of the mechanical pump body, the second end of the first oil inlet passage is connected to the positive rotation negative pressure side of the internal gear, and the second end of the second oil inlet passage is connected to the reverse rotation negative pressure side of the internal gear; The first ends of the first oil outlet channel and the second oil outlet channel are connected to the oil outlet hole of the mechanical pump body, the second end of the first oil outlet channel is connected to the forward high-pressure side of the internal gear, and the second end of the second oil outlet channel is connected to the reverse high-pressure side of the internal gear.

9. An electric drive assembly, wherein: include: A housing having a mounting cavity; A motor assembly is disposed in the installation cavity; A speed change gear set is arranged in the installation cavity and is drivingly connected to the motor assembly; as well as According to any one of claims 1 to 8, the mechanical oil pump is disposed in the mounting cavity.

10. A vehicle, wherein: It comprises the electric drive assembly as claimed in claim 9, wherein the electric drive assembly is provided in two groups, one for the front drive of the vehicle and the other for the rear drive of the vehicle, and the two groups of the electric drive assemblies face in opposite directions.

11. A method for controlling a cooling system, wherein: Applicable to the cooling system according to any one of claims 1 to 8, the control method comprises: Obtaining the current temperature of the motor component; Get the current vehicle speed; comparing the current temperature with a first preset temperature; If the current temperature is higher than the first preset temperature, comparing the current vehicle speed with the first preset vehicle speed; If the current vehicle speed is lower than the first preset vehicle speed, the electronic oil pump is controlled to start.

12. The control method of the cooling system according to claim 11, wherein: If the current vehicle speed is lower than the first preset vehicle speed, after the step of controlling the electronic oil pump to start, the control method includes: If the current vehicle speed is higher than a second preset vehicle speed, the electronic oil pump is controlled to be turned off, and the second preset vehicle speed is greater than or equal to the first preset vehicle speed.

13. The control method of the cooling system according to claim 12, wherein: The first preset oil temperature is -30°C; and / or The first preset vehicle speed ranges from 30 to 40 km / h.

14. A method for controlling a cooling system, wherein: Applicable to the cooling system as claimed in claim 6, the control method comprising: Get the current oil temperature; If the current oil temperature is lower than a second preset temperature, adjusting the thermostat to enter the first circulation loop; If the current oil temperature is greater than or equal to the second preset temperature, the thermostat is adjusted to enter the second circulation loop.

15. The control method of the cooling system according to claim 14, wherein: The second preset oil temperature is 60°C.

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