Electric drive system and lubricating oil flow control method

Abstract

The invention discloses an electric driving system and a lubricating oil flow control method, and belongs to the technical field of vehicle electric driving systems. The electric driving system comprises a driving motor which is provided with a motor shell, and an oil level sensing hole and a first oil conveying hole are formed in the motor shell; the gear box is connected with the driving motor in a matched mode, and a second oil conveying hole is formed in the gear box; the electronic oil pump comprises a pump body and a pump motor which are connected in a matched mode, an oil inlet of the pump body is connected with the first oil conveying hole and the second oil conveying hole, a cooling oil inlet of the pump motor is connected with an oil outlet of the pump body, and a cooling oil outlet of the pump motor is connected with an oil inlet of the pump body. A third oil conveying hole is formed in a shell of the pump motor, and the oil level sensing hole is connected with the third oil conveying hole. And the controller is connected with the electronic oil pump and the driving motor. According to the electric driving system and the lubricating oil liquid flow control method, the heat dissipation efficiency and the driving efficiency can be improved.

Description

Technical Field

[0001] This application belongs to the field of vehicle electric drive system technology, and particularly relates to an electric drive system and a lubricating oil flow control method. Background Technology

[0002] In automotive electric drive systems, a common oil-based lubrication and cooling system for gear shafts and motors is used, where the circulating flow of oil serves both lubrication and cooling functions. Specifically, the oil circulates within the gearbox and motor housing; in conjunction with this, an electronic oil pump draws the oil and pumps it to the motor, gear shafts, and other components to achieve both cooling and lubrication.

[0003] However, in actual operation, due to factors such as temperature and oil quality, the efficiency of oil return from the motor housing to the gearbox or oil pan is not ideal, and it tends to accumulate at the bottom of the motor housing. If the oil level is too high, the lower part of the motor stator will be submerged in the hot oil that has already carried away the heat from the motor, leading to poor heat dissipation of the motor stator and affecting the circulation lubrication and heat dissipation effects. At the same time, excessive oil will also increase the rotational resistance of the motor rotor, resulting in excessive rotational energy loss and affecting the overall efficiency of the machine. Summary of the Invention

[0004] This application provides an electric drive system and a lubricating oil flow control method, aiming to at least partially solve the technical problems of unsatisfactory circulating lubrication and cooling efficiency in electric drive systems, poor stator heat dissipation, high rotor rotation resistance, and low drive efficiency. Therefore,

[0005] According to one aspect of this application, an electric drive system is provided, comprising:

[0006] A drive motor has a motor housing, and the motor housing is provided with an oil level sensing hole and a first oil supply hole;

[0007] A gearbox is connected to the drive motor, and a second oil supply hole is provided on the gearbox;

[0008] An electronic oil pump includes a pump body and a pump motor that are matched and connected. The oil inlet of the pump body is connected to the first oil delivery port and the second oil delivery port respectively. The cooling oil inlet of the pump motor is connected to the oil outlet of the pump body. The cooling oil outlet of the pump motor is connected to the oil inlet of the pump body. A third oil delivery port is provided on the housing of the pump motor. The oil level sensing hole is connected to the third oil delivery port.

[0009] The controller is connected to the electronic oil pump to obtain the drive current value of the electronic oil pump in its current state, compare the drive current value with a preset current threshold, and then increase or maintain the drive current value applied to the electronic oil pump based on the comparison result. When the drive current value is greater than the preset current threshold, the drive current applied to the electronic oil pump is further increased, thereby increasing the pumping flow rate of the electronic oil pump and reducing the oil level in the motor housing.

[0010] In some embodiments, the motor housing, the gearbox housing, the pump body housing, and the pump motor housing are integrated into one unit.

[0011] In some embodiments, the oil level sensing hole is located at the bottom of the motor housing.

[0012] In some embodiments, the third oil inlet is located on the top of the housing of the pump motor.

[0013] In some embodiments, a suction filter is provided inside the gearbox, and the outlet of the suction filter is connected to the second oil delivery hole.

[0014] In some embodiments, the oil inlet of the suction filter is located at the bottom of the gearbox.

[0015] In some embodiments, the electric drive system further includes a temperature sensor disposed within the motor housing and connected to the controller to detect the oil temperature.

[0016] Another aspect of this application embodiment provides a lubricating oil flow control method based on the aforementioned electric drive system; the control method includes:

[0017] The controller acquires the drive current of the electronic oil pump and a preset current threshold, and compares the drive current with the preset current threshold.

[0018] Based on the comparison results, the drive current applied to the electronic oil pump is controlled so that when the drive current value is greater than the preset current threshold, the drive current applied to the electronic oil pump is further increased, thereby increasing the pumping flow rate of the electronic oil pump and reducing the oil level in the motor housing.

[0019] The above operation is repeated until the driving current is less than or equal to the preset current threshold.

[0020] Wherein, when the oil level in the motor housing is at a set level height, the drive current for the electronic oil pump to maintain a set speed is the preset current threshold.

[0021] In some embodiments, controlling the drive current applied to the electronic oil pump based on the comparison result includes:

[0022] If the drive current is greater than the preset current threshold, the drive current applied to the electronic oil pump is increased.

[0023] If the drive current is less than or equal to the preset current threshold, the current drive current applied to the electronic oil pump is maintained.

[0024] In some embodiments, the controller acquires the preset current threshold of the electronic oil pump by:

[0025] The current temperature of the oil inside the motor housing is obtained, and the corresponding preset current threshold is determined based on the temperature;

[0026] Wherein, when the oil level in the motor housing is a set liquid level height and the electronic oil pump maintains a set speed, the drive current corresponding to different current temperatures is the preset current threshold.

[0027] The embodiments of this application have at least the following beneficial effects:

[0028] The electric drive system and lubricating oil flow control method provided in this application embodiment include a drive motor, a gearbox, an electronic oil pump, and a controller. The drive motor housing is provided with an oil level sensing hole and a first oil delivery hole. The gearbox has a second oil delivery hole. The oil inlet of the electronic oil pump body is connected to the first and second oil delivery holes. The pump motor housing of the electronic oil pump has a third oil delivery hole connected to the oil level sensing hole. The pump motor's cooling oil inlet is connected to the pump body's oil inlet, and the cooling oil outlet is connected to the pump body's oil inlet, thereby ensuring that the oil in the motor housing... The oil can enter the pump motor, increasing its rotational resistance. To maintain the rotational speed and pumping flow rate, the required drive current for the pump motor will increase significantly. As the liquid level increases, the amount of oil entering the pump motor will also increase. Therefore, once the controller detects that the drive current of the pump motor has increased significantly and exceeds a preset threshold, it can further increase the drive current applied to the pump motor to improve the pumping capacity. The accumulated oil is quickly extracted through the first oil outlet, improving the oil circulation cooling and lubrication efficiency, thereby rapidly reducing rotational resistance and improving transmission efficiency and stator heat dissipation efficiency. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic diagram of the structure of the electric drive system in an embodiment of this application is shown;

[0031] Figure 2 A schematic diagram of the control architecture in an embodiment of this application is shown. Attached image description:

[0033] 1-Drive motor, 11-Motor housing, 111-First oil supply port, 112-Oil level sensing port, 12-Stator, 13-Rotor;

[0034] 2-Gearbox, 21-Box body, 211-Second oil inlet, 22-Suction filter;

[0035] 3-Electronic oil pump, 31-Pump body, 311-Pump body oil inlet, 312-Pump body oil outlet, 32-Pump motor, 321-Cooling oil inlet, 322-Cooling oil outlet, 323-Third oil delivery hole;

[0036] 4-Controller. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0038] Furthermore, reference numerals and / or reference letters may be repeated in different examples in this application. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed. In addition, this application provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0039] This application is described below with reference to the accompanying drawings and specific embodiments:

[0040] In automotive electric drive systems, a shared oil lubrication and motor cooling system is typically used. This means that the circulating oil serves both lubrication and cooling functions, circulating within the gearbox and motor housing. However, in actual operation, factors such as temperature and oil quality can affect the efficiency of oil return from the motor housing to the gearbox or oil pan, leading to oil accumulation at the bottom of the motor housing. Excessive oil accumulation can cause poor heat dissipation from the motor stator, affecting both lubrication and cooling performance. Furthermore, excessive oil increases the rotor's rotational resistance, resulting in excessive rotational energy loss and impacting overall drive efficiency.

[0041] Therefore, this application provides an electric drive system and a lubricating oil flow control method, which aims to solve to some extent the technical problems of unsatisfactory circulating lubrication and cooling efficiency of electric drive systems, poor heat dissipation of motor stator, high rotor rotation resistance, and low drive efficiency.

[0042] See Figure 1 and Figure 2 In some embodiments, the electric drive system includes a drive motor 1, a gearbox 2, an electronic oil pump 3, and a controller 4 connected in cooperation. The oil flows between the drive motor 1 and the gearbox 2 under the drive of the electronic oil pump 3 to achieve circulating cooling and lubrication.

[0043] Of course, the drive motor 1 and the electronic oil pump 3 can work together under the control of the controller 4, such as matching and adjusting the output power of the drive motor and the pumping flow rate of the electronic oil pump 3, so as to ensure the lubrication and cooling effect under different output states.

[0044] The drive motor 1 may include a motor housing 11 and a stator 12 and a rotor 13 disposed therein. The stator 12 is fixed to the motor housing 11, and the rotor 13 is rotatably mounted on the motor housing 11 via a shaft. The rotor 13 can be disposed within the magnetic field of the stator 12 to rotate under the action of electromagnetic driving force, outputting driving torque externally. The motor housing 11 is provided with a first oil inlet 111 and an oil level sensing hole 112. The first oil inlet 111 is used to discharge oil that has completed lubrication and cooling operations. The motor housing 11 is also provided with an oil inlet, an oil inlet nozzle, and other structures for injecting oil into the motor housing 11 (not shown in the figure), thereby achieving circulating lubrication and cooling inside and outside the motor housing 11. Generally, the drive motor 1 should also be equipped with a drive control chip or circuit components to receive control commands from upstream control equipment (such as an on-board ECU or MCU) and control parameters such as the speed of the drive motor 1.

[0045] The gearbox 2 is a transmission mechanism, which can be equipped with transmission gear sets and other transmission components, and is connected to the output shaft of the drive motor 1. Typically, the transmission gear sets and other components require timely lubrication and cooling; therefore, they can be cooled and lubricated together with the drive motor 1 by circulating oil. The gearbox 2's housing 21 has a second oil inlet 211 for supplying oil filtered by a filter; of course, the gearbox 2 should also be equipped with an oil inlet, oil inlet nozzle, and other structures for injecting oil into the gearbox 2 (not shown in the figure), thereby achieving circulating lubrication and cooling inside and outside the gearbox.

[0046] The electronic oil pump 3 is a power component for oil circulation, connected to the inlet and outlet structures on the motor housing 11 and the gearbox 2 respectively, to realize the circulation of oil. Specifically, the electronic oil pump 3 includes a pump body 31 and a pump motor 32 connected in cooperation. The pump motor 32 drives the pump wheel inside the pump body 31 to rotate, creating a pressure difference between the pump body inlet 311 and the pump body outlet 312, thereby drawing oil from the pump body inlet 311 into the pump body 31 and pumping it out from the pump body outlet 312. The pump body inlet 311 is connected to the first oil delivery hole 111 and the second oil delivery hole 211, thereby drawing oil out of the motor housing 11 and the housing 21, and then pumping it to components or parts that require lubrication and cooling.

[0047] The pump motor 32 is provided with a cooling oil inlet 321 and a cooling oil outlet 322 for circulating oil cooling and lubrication of the pump motor 32. The cooling oil inlet 321 can be connected to the pump body oil outlet 312, and the cooling oil outlet 322 can be connected to the pump body oil inlet 311 to realize the circulating oil cooling of the pump motor.

[0048] It is worth noting that the pump motor 32 has a third oil inlet 323 on its housing, which is connected to the oil level sensing hole 112. This allows oil in the motor housing 11 to enter the pump motor 32 through the oil level sensing hole 112 and the third oil inlet 323. This increases the rotor rotation resistance of the pump motor 32 by providing pressure through oil contact, and the resistance increases with the oil level in the motor housing 11. Correspondingly, to maintain pumping capacity, the drive current applied to the pump motor 32 needs to be increased accordingly to maintain the pump wheel speed within the body 31. Once the drive voltage applied to the pump motor 32 exceeds a preset current threshold, it means that oil accumulates to a certain height in the motor housing 11, which has a significant adverse impact on the stator heat dissipation and rotor rotation efficiency of the drive motor.

[0049] The pump wheel speed of the electronic oil pump 3 is controlled by the feedback of the control circuit board on the electronic oil pump 3. That is, when the speed of the pump motor 32 is reduced due to the resistance of the oil, the control circuit board can increase the drive current loaded on the pump motor 32 to keep the speed constant, thereby maintaining the stability of the pumping capacity.

[0050] To this end, the controller 4 can communicate in real time with the control chip of the pump motor 32 to collect the current driving current applied to the pump motor 32 and compare it with a preset current threshold in the controller 4. This allows the controller to determine whether the liquid level in the motor housing 11 exceeds the limit and whether the oil needs to be drained in time. Generally, when the controller 4 determines that the driving current of the pump motor 32 is greater than the preset current threshold, it will control the control circuit board of the pump motor 32 to further increase the driving current, thereby increasing the speed of the pump motor 32 and the impeller speed in the pump body 31, improving the pumping capacity, and thus quickly drawing the oil from the motor housing 11 and accelerating the oil discharge from the motor housing 11. As the oil is discharged, the liquid level in the motor housing 11 drops rapidly, and the oil pressure entering the pump motor 32 through the oil level sensing hole 112 and the third oil delivery hole 323 drops significantly. Consequently, the driving current on the pump motor 32 decreases, and the controller 4 can correspondingly control the control circuit board of the pump motor 32 to reduce the driving current until the driving current drops below the preset current value. Generally, the change in the driving current can be set to a unit change as needed. Each time the driving current is adjusted, it can be increased or decreased according to a multiple of the unit change to adjust the driving current.

[0051] The oil entering through the third oil inlet 323 will be discharged from the pump motor 32 through the cooling outlet 322 along with the circulating cooling oil, thereby ensuring sufficient oil pressure and applying hydraulic resistance to the rotor of the pump motor 32.

[0052] In some embodiments, the motor housing 11, the casing 21, the pump body 31 housing, and the pump motor 32 housing can be integrated into one unit. For example, a housing with a specific cavity structure and flow channel structure can be formed through processes such as casting or stamping, for fixing and installing various functional components such as the motor stator, motor rotor, gear set, and pump impeller.

[0053] The integrated housing can also be configured into multiple pieces that can be assembled, as needed, to reduce manufacturing difficulty and the difficulty of assembling its internal components.

[0054] Among them, the integrated manufacturing of the shell can greatly simplify the difficulty of fitting and connecting the functional holes, flow channels and other structures of the structure.

[0055] In some embodiments, considering that the oil is greatly affected by gravity, in order to ensure the reliability of oil pressure conduction, the oil level sensing hole 112 can be set at a relatively low position on the motor housing 11, such as the bottom of the motor housing 11, thereby ensuring the reliability of pressure conduction.

[0056] In some embodiments, in order to ensure stable oil pressure in the motor housing 11, the third oil inlet 323 may be correspondingly provided on the top of the housing of the pump motor 32, so that the oil can stably enter the pump motor 32 and stabilize the pressure.

[0057] Correspondingly, the pump motor 32 can be located below the motor housing 11.

[0058] In some embodiments, in order to ensure the quality of oil circulation, a suction filter 22 can be installed in the tank 21. The outlet of the suction filter 22 is connected to the second oil delivery hole 211, so that the oil discharged from the tank 21 will be filtered and then circulated to the cooling and lubrication objects to ensure the quality of oil and help improve the fluidity and oil quality.

[0059] In some embodiments, in order to ensure the reliability of filtration, the oil inlet of the suction filter 22 can be located in the bottom area of ​​the housing 21, so that it can be fully immersed in the oil and ensure filtration efficiency.

[0060] In some embodiments, the electric drive system may further include a temperature sensor (not shown in the figure), which is disposed inside the motor housing 11 and connected to the controller 4 to monitor the oil temperature in real time and transmit the data back to the controller 4 so that the controller 4 can adjust the drive current applied to the pump motor 32 based on the real-time temperature, thereby ensuring the pumping cycle efficiency.

[0061] Especially at low temperatures, the fluidity of the oil is poor. In order to maintain lubrication reliability, it is necessary to improve the pumping capacity and promote oil circulation.

[0062] Of course, when the oil temperature is high, the oil has better fluidity, and the drive current of the pump motor 32 can be appropriately reduced to achieve energy saving.

[0063] It is worth noting that, considering the influence of temperature on oil flow, temperature can also be used as a basis for adjusting the preset current threshold. That is, the preset current threshold can be relatively larger when the temperature is low and relatively smaller when the temperature is high, so as to balance lubrication and cooling effect with energy consumption control.

[0064] In some embodiments, a lubricating oil flow control method based on the above-mentioned electric drive system is also provided; the control method is mainly a control strategy scheme executed by the controller 4 based on parameters such as the real-time monitored drive current of the pump motor 32 and preset current threshold.

[0065] The control method includes:

[0066] The controller 4 acquires the drive current of the electronic oil pump 3 and a preset current threshold, and compares the drive current with the preset current threshold.

[0067] Based on the comparison results, the drive current applied to the electronic oil pump 3 is controlled;

[0068] The above operation is repeated until the driving current is less than or equal to the preset current threshold.

[0069] Wherein, when the oil level in the motor housing 11 is at a set liquid level height, the drive current for the pump body 31 to maintain a set rotation speed is the preset current threshold.

[0070] In other words, the controller 4 has the preset current threshold stored in it and acquires the drive current value of the electronic oil pump 3 in real time. Then, it compares the data and controls the magnitude of the drive current loaded on the pump motor 32 according to the comparison result, that is, it can further increase, maintain the current value, or even decrease it.

[0071] The specific value of the preset current threshold can be obtained through multiple experiments.

[0072] In some embodiments, the magnitude of the drive current can be adjusted based on a multiple of the unit change in current, thereby enabling stable and linear adjustment of the current to ensure control reliability and stability.

[0073] In some embodiments, a control strategy based on comparison results is provided, namely, controlling the drive current applied to the electronic oil pump 3 based on the comparison results includes:

[0074] When the driving current is greater than the preset current threshold, the driving current applied to the pump motor 32 is increased; thereby further increasing the pumping capacity and promoting the discharge of oil from the motor housing 11.

[0075] If the drive current is less than or equal to the preset current threshold, the current drive current applied to the pump motor 32 is maintained, indicating that it is not necessary to discharge the oil in the motor housing 11 at present, and the impact is acceptable.

[0076] In some embodiments, considering that temperature has a significant impact on oil fluidity, the control method incorporates temperature into its control strategy design.

[0077] The controller obtains the preset current threshold of the electronic oil pump, including:

[0078] The current temperature of the oil inside the motor housing 11 is obtained, and the corresponding preset current threshold is determined based on the temperature;

[0079] Wherein, when the oil level in the motor housing 11 is a set liquid level height and the electronic pump maintains a set speed, the drive current corresponding to different current temperatures is the preset current threshold.

[0080] The specific value of the preset current threshold can be obtained through multiple experiments.

[0081] In other words, multiple preset current thresholds can be set according to different temperatures. Once the current oil temperature is determined, the corresponding preset current threshold is determined and used for comparison.

[0082] In some embodiments, the controller 4 may also adjust the drive current applied to the pump motor 32 based on the difference between the real-time drive current and a preset current threshold.

[0083] When the controller 4 detects a deviation between the drive current value of the pump motor 32 and the preset current threshold, it can determine the adjustment range of the current drive current value based on the deviation. For example, an adjustment value can be set for a certain range of deviation. After determining the deviation, the corresponding adjustment value can be obtained by following the pattern, thereby increasing or decreasing the drive current.

[0084] The embodiments of this application have at least the following beneficial effects:

[0085] The electric drive system and lubricating oil flow control method provided in this application embodiment include a drive motor, a gearbox, an electronic oil pump, and a controller. The drive motor housing is provided with an oil level sensing hole and a first oil delivery hole. The gearbox has a second oil delivery hole. The oil inlet of the electronic oil pump body is connected to the first and second oil delivery holes. The pump motor housing of the electronic oil pump has a third oil delivery hole connected to the oil level sensing hole. The pump motor's cooling oil inlet is connected to the pump body's oil inlet, and the cooling oil outlet is connected to the pump body's oil inlet, thereby ensuring that the oil in the motor housing... The oil can enter the pump motor, increasing its rotational resistance. To maintain the rotational speed and pumping flow rate, the required drive current for the pump motor will increase significantly. As the liquid level increases, the amount of oil entering the pump motor will also increase. Therefore, once the controller detects that the drive current of the pump motor has increased significantly and exceeds a preset threshold, it can further increase the drive current applied to the pump motor to improve the pumping capacity. The accumulated oil is quickly extracted through the first oil outlet, improving the oil circulation cooling and lubrication efficiency, thereby rapidly reducing rotational resistance and improving transmission efficiency and stator heat dissipation efficiency.

[0086] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0087] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0088] It should be noted that all directional indications in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0089] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0090] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0091] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0092] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0093] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. An electric drive system, characterized in that, include: A drive motor has a motor housing, and the motor housing is provided with an oil level sensing hole and a first oil supply hole; A gearbox is connected to the drive motor, and a second oil supply hole is provided on the gearbox; An electronic oil pump includes a pump body and a pump motor that are matched and connected. The oil inlet of the pump body is connected to the first oil delivery port and the second oil delivery port respectively. The cooling oil inlet of the pump motor is connected to the oil outlet of the pump body. The cooling oil outlet of the pump motor is connected to the oil inlet of the pump body. A third oil delivery port is provided on the housing of the pump motor. The oil level sensing hole is connected to the third oil delivery port. The controller is connected to the electronic oil pump to obtain the drive current value of the electronic oil pump in its current state, compare the drive current value with a preset current threshold, and then increase or maintain the drive current value applied to the electronic oil pump based on the comparison result. When the drive current value is greater than the preset current threshold, the drive current applied to the electronic oil pump is further increased, thereby increasing the pumping flow rate of the electronic oil pump and reducing the oil level in the motor housing.

2. The electric drive system as described in claim 1, characterized in that, The motor housing, the gearbox housing, the pump body housing, and the pump motor housing are integrated into one unit.

3. The electric drive system as described in claim 1, characterized in that, The oil level sensing hole is located at the bottom of the motor housing.

4. The electric drive system as described in claim 3, characterized in that, The third oil delivery port is located at the top of the pump motor housing.

5. The electric drive system as described in claim 1, characterized in that, The gearbox is equipped with a suction filter, and the outlet of the suction filter is connected to the second oil delivery hole.

6. The electric drive system as described in claim 5, characterized in that, The oil inlet of the suction filter is located at the bottom of the gearbox.

7. The electric drive system as described in claim 1, characterized in that, The electric drive system also includes a temperature sensor, which is located inside the motor housing and connected to the controller to detect the oil temperature.

8. A method for controlling the flow rate of lubricating oil, characterized in that, Based on the electric drive system according to any one of claims 1 to 7; the control method includes: The controller acquires the drive current of the electronic oil pump and a preset current threshold, and compares the drive current with the preset current threshold. Based on the comparison results, the drive current applied to the electronic oil pump is controlled so that when the drive current value is greater than the preset current threshold, the drive current applied to the electronic oil pump is further increased, thereby increasing the pumping flow rate of the electronic oil pump and reducing the oil level in the motor housing. The above operation is repeated until the driving current is less than or equal to the preset current threshold. Wherein, when the oil level in the motor housing is at a set level height, the drive current for the electronic oil pump to maintain a set speed is the preset current threshold.

9. The lubricating oil flow control method as described in claim 8, characterized in that, The control of the drive current applied to the electronic oil pump based on the comparison results includes: If the drive current is greater than the preset current threshold, the drive current applied to the electronic oil pump is increased. If the drive current is less than or equal to the preset current threshold, the current drive current applied to the electronic oil pump is maintained.

10. The lubricating oil flow control method as described in claim 8, characterized in that, The controller obtains the preset current threshold of the electronic oil pump, including: The current temperature of the oil inside the motor housing is obtained, and the corresponding preset current threshold is determined based on the temperature; Wherein, when the oil level in the motor housing is a set liquid level height and the electronic oil pump maintains a set speed, the drive current corresponding to different current temperatures is the preset current threshold.

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