Electric Drive Oil Level Test System and Method

Abstract

This application discloses an electric drive oil level testing system and method, belonging to the field of electric drive system testing technology. The system includes: an electric drive support fixture and an oil level test bench; the electric drive support fixture supports the electric drive assembly, which includes a motor and a differential located in the same cavity, the cavity being filled with lubricating oil, and the half-shaft gears in the differential being configured for synchronized speed; the oil level test bench is equipped with a dynamometer, a data acquisition device, and a main control device; the dynamometer is used to drive the half-shaft gears of the differential to rotate based on different set speeds; the data acquisition device is used to collect the differential speed and differential torque during rotation; the main control device is used to generate speed-torque curves under different lubricating oil levels based on the differential speed and differential torque, the speed-torque curves being used to characterize the change in differential torque under different differential speeds.

Description

Technical Field

[0001] This application relates to the field of electric drive system testing technology, and in particular to an electric drive oil level testing system and method. Background Technology

[0002] An electric drive system is composed of various components such as a motor, a reducer, and a motor control unit (MCU). The integrated design of the electric drive system can reduce vehicle weight, improve overall vehicle performance, and also reduce the overall size of vehicle components, thereby increasing the utilization of interior space. The electric drive system also includes a differential, which may be integrated into the reducer or exist independently of the reducer.

[0003] Lubricating oil is used to cool the internal temperature of the electric drive assembly and reduce friction and wear between components. Too much or too little lubricating oil added to the cavity containing the motor will affect the performance of the electric drive assembly. Before leaving the factory, the electric drive assembly needs to undergo an oil level test to determine the relationship between speed, torque and lubricating oil volume, thereby determining the optimal lubricating oil volume to improve electric drive performance.

[0004] However, when measuring torque, the differential torque on the electric drive assembly is difficult to measure because the motor and differential are integrated in the same cavity. Summary of the Invention

[0005] This application provides an electrically driven oil level testing system and method. The technical solution is as follows:

[0006] On one hand, embodiments of this application provide an electrically driven oil level testing system, the system comprising: an electrically driven support fixture and an oil level testing bench;

[0007] The electric drive support fixture is used to support the electric drive assembly, which includes a motor and a differential located in the same cavity. The cavity is filled with lubricating oil, and the half-shaft gears in the differential are configured to rotate synchronously.

[0008] The oil level test bench is equipped with a dynamometer, data acquisition equipment, and main control equipment.

[0009] The dynamometer is used to drive the half-shaft gear of the differential to rotate based on different set speeds;

[0010] The acquisition device is used to acquire the differential speed and differential torque of the differential during rotation.

[0011] The main control device is used to generate a speed-torque curve graph under different lubricating oil filling amounts based on the differential speed and the differential torque. The speed-torque curve graph is used to characterize the change of the differential torque under different differential speeds.

[0012] On the other hand, embodiments of this application provide an electrically driven oil level testing method, the method being used in the main control device of the system described above, the method comprising:

[0013] Send a drive command to the dynamometer, the drive command being used to instruct the dynamometer to drive the half-shaft gear of the differential to rotate based on a set speed;

[0014] During rotation, the differential speed and differential torque are collected by the receiving and acquisition equipment.

[0015] Based on the differential speed and the differential torque, a speed-torque curve is generated under different lubricant filling amounts. The speed-torque curve is used to characterize the change of the differential torque under different differential speeds.

[0016] In this embodiment, when the motor and differential are located in the same cavity, it is difficult to add equipment for measuring differential speed and differential torque inside the cavity. The main control equipment of the oil level test bench controls the dynamometer of the oil level test bench to mechanically drive the differential of the electric drive assembly, without having to drive the motor through the motor controller and then drive the differential, thus avoiding high voltage damage to the motor controller. The acquisition equipment on the oil level test bench can measure the differential speed and differential torque outside the cavity, solving the problem that the oil level test bench is difficult to measure the torque of the integrated electric drive assembly, and improving the accuracy and reliability of the speed-torque curve. Attached Figure Description

[0017] Figure 1 This is a structural diagram of an electrically driven oil level testing system provided in an exemplary embodiment of this application;

[0018] Figure 2 This is an exemplary example of the speed-torque curve provided in this application;

[0019] Figure 3 A schematic cross-sectional view of the differential is shown;

[0020] Figure 4 A schematic diagram of gear rotation inside the differential is shown;

[0021] Figure 5 A schematic cross-sectional view of a differential after welding and fixing, provided in an exemplary embodiment of this application, is shown.

[0022] Figure 6 A schematic diagram of the drive shaft connection fixture is shown;

[0023] Figure 7 A schematic diagram showing the connection between a dynamometer and a differential is provided in an exemplary embodiment of this application;

[0024] Figure 8 A schematic diagram of an electrically driven support fixture provided in an exemplary embodiment of this application is shown;

[0025] Figure 9 A schematic diagram showing the connection between the electric drive assembly and the electric drive support fixture is shown;

[0026] Figure 10 This is a schematic diagram showing the connection between the electric drive assembly and the oil level test bench provided in another exemplary embodiment of this application;

[0027] Figure 11 A flowchart of an exemplary embodiment of the present application is shown;

[0028] Figure 12 A schematic diagram illustrating an embodiment of the oil level test method provided in this application is shown. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0030] The relevant terms will be explained below.

[0031] Electric drive system: Composed of components such as motor, reducer, and motor controller, it is the core component that drives the vehicle. The integrated design of the electric drive system can reduce vehicle weight, improve overall vehicle performance, and also reduce the overall size of vehicle components, thereby increasing the utilization of interior space.

[0032] Differential: When a vehicle is turning, the differential allows the two half-shafts to rotate at different speeds, enabling the wheels on both sides to roll at different speeds. In an electric drive assembly, the differential can be a component of the reducer, which is used to achieve deceleration. Optionally, since electric drive assemblies can have various different configurations, the differential may not be integrated into the reducer.

[0033] Lubricating oil: Used to cool and lubricate internal components such as the motor and reducer of the electric drive assembly. Too much or too little lubricating oil will affect the performance of the electric drive assembly.

[0034] Oil Level Test: The oil level test is used to determine the appropriate amount of lubricating oil to be added to the electric drive assembly to maximize its lubricating and cooling effects. The lubricating oil in the electric drive assembly lubricates and cools various components. Excessive lubricating oil leads to prolonged residence time within the assembly, potentially causing internal temperature increases, and also increases internal resistance. Insufficient lubricating oil, on the other hand, results in inadequate lubrication of components, leading to wear, and also causes insufficient heat absorption, resulting in increased internal temperature. The oil level test is conducted on an oil level test bench.

[0035] Torque: The torque required for the motor to drive the differential. Since torque reflects the internal resistance of the electric drive assembly, measuring torque can help adjust the amount of lubricating oil added.

[0036] Torque flange: A device used to measure torque.

[0037] Dynamometer (DYNO): A device used to measure the output power of an electric drive assembly. In this application, the power can be determined based on the product of the differential speed and the differential torque. The dynamometer is mainly used to drive the internal gears of the differential to rotate according to a set speed.

[0038] As electric drive systems in new energy vehicles become more integrated and lightweight, electric drive assemblies integrating components such as motors, reducers, and MCUs have emerged. Heat concentrates among the components located within the same housing, causing the electric drive assembly to overheat and requiring lubricating oil for cooling. The amount of lubricating oil added also affects the performance of the electric drive assembly; as the amount of lubricating oil increases, the electric drive efficiency initially rises and then falls. Determining the appropriate amount of lubricating oil for the electric drive assembly can reduce heat, lubricate components, maintain component safety, extend service life, and improve electric drive efficiency.

[0039] During the oil level test to determine the lubricating oil filling amount, the oil level test bench (used to collect measurement data and generate test results during the test) measures test data such as temperature, speed, torque, pressure, and power generated by the electric drive assembly under different filling amounts in order to determine the appropriate lubricating oil filling amount. The torque measured in the oil level test is the no-load torque, that is, the torque required for the motor in the electric drive assembly to overcome internal resistance and operate its internal components without external load.

[0040] In related technologies, when measuring the optimal lubricant level for an electric drive system, the overall layout of the electric drive system on a vehicle is simulated on an oil level test bench. A motor controller controls the motor to drive the electric drive system, allowing for the measurement of test data within the system. For example, sensors are installed on the bearings between the motor and the reducer to measure motor speed and torque. However, when the motor and reducer are integrated into the same housing, there is no additional space inside the housing to install sensors, making it difficult to measure motor speed and torque. Furthermore, the electric drive assembly uses high-voltage electricity, posing a risk of high-voltage damage to the MCU during testing.

[0041] This application provides an oil level testing system that solves the problem that oil level test benches cannot measure the torque of integrated electric drive assemblies. The system drives the differential of the electric drive assembly mechanically, without energizing the electric drive assembly, thereby measuring the differential speed and differential torque of the electric drive assembly during operation and obtaining speed-torque curves under different lubrication amounts, so as to determine the amount of lubricating oil to be added.

[0042] join Figure 1 , Figure 1 This is a structural diagram of an electrically driven oil level testing system provided in an exemplary embodiment of this application. The system includes: an electrically driven support fixture 110 and an oil level testing bench 120.

[0043] The electric drive support fixture 110 is used to support the electric drive assembly 111, which includes a motor 112 and a differential 113 located in the same cavity. The cavity is filled with lubricating oil, and the half-shaft gear 114 in the differential 113 is set to synchronize speed.

[0044] In some embodiments, the electric drive support fixture 110 carries the electric drive assembly 111, aligning the electric drive assembly 111 with the dynamometer 121 on the oil level test bench 120, so that the differential 113 can be connected to the dynamometer 121.

[0045] In some embodiments, when the gears inside the electric drive assembly 111 rotate, the lubricating oil is stirred into the various parts within the cavity where the differential 113 is located, achieving a lubricating effect and carrying away heat when it leaves the parts, thus achieving a cooling function. The lubricating oil can be injected from the oil filler port on the outside of the electric drive assembly 111 and discharged from the oil drain port, so as to control the amount of oil added during the oil level test.

[0046] In some embodiments, besides the differential 113 and the motor 112, other components exist inside the cavity where the differential 113 is located, for transmitting power or performing specific functions. For example, components such as shaft gears are used to transmit power, and the reducer has a deceleration function. It should be noted that in the actual application scenario of the electric drive assembly 111, the electric drive assembly 111 should also include a motor controller, which is used to control the operation of the motor 112. Since the motor controller and the motor 112 are located in different cavities, and the internal components of the electric drive assembly 111 in this embodiment do not control the motor 112 through the motor controller, the electric drive assembly 111 in this embodiment may also not include a motor controller.

[0047] In some embodiments, when the half-shaft gears 114 in the differential 113 rotate at synchronized speeds, the differential 113 can reverse drive other components inside the electric drive assembly 111, excluding the differential 113, to operate.

[0048] The oil level test bench 120 is equipped with a dynamometer 121, a data acquisition device 122, and a main control device 123.

[0049] The dynamometer 121 is used to drive the half-shaft gear 114 of the differential 113 to rotate based on different set speeds.

[0050] In some embodiments, the dynamometer 121 is also used to receive a set speed sent by the main control device 123.

[0051] Optionally, the differential 113 may contain two opposing half-shaft gears 114. In a vehicle driving scenario, the half-shaft gears 114 can be connected to the wheels via a drive shaft and rotate synchronously with the wheels they are connected to.

[0052] It should be noted that, in this embodiment of the application, the dynamometer 121 on the oil level test bench 120 can be used to perform other functions during other tests, such as measuring motor power. By utilizing this dynamometer 121, it is possible to avoid frequently changing the arrangement of the oil level test bench 120 and reduce the difficulty of the test.

[0053] The data acquisition device 122 is used to acquire the differential speed and differential torque of the differential 113 during rotation.

[0054] In some embodiments, the differential speed is used to characterize the rotational speed of the half-shaft gear 114 when the dynamometer 121 drives the half-shaft gear 114 to rotate. Since the rotational speed of the half-shaft gear 114 is the same as the rotational speed of the drive shaft, the differential speed can also characterize the rotational speed of the drive shaft.

[0055] In some embodiments, the differential torque refers to the torque required by the dynamometer 121 to drive the half-shaft gear 114 of the differential 113 to rotate, thereby driving other components inside the electric drive assembly 111.

[0056] Optionally, the data acquisition device 122 can also collect data such as the temperature and pressure of the lubricating oil and the temperature and pressure of the cooling water during the oil level test to adjust the overall working conditions (operating conditions) and ensure that the measurement process of the differential speed and differential torque is carried out under the set temperature, pressure and lubricating oil filling amount.

[0057] The main control device 123 is used to generate speed-torque curves under different lubricant filling amounts based on the differential speed and differential torque. The speed-torque curves are used to characterize the changes in differential torque under different differential speeds.

[0058] In some embodiments, the main control device 123 is also used to send a set speed to the dynamometer 121 in order to generate a speed-torque curve under different lubricating oil filling amounts, thus solving the problem that the motor controller has difficulty controlling the speed.

[0059] It should be noted that the set speed is different from the differential speed. The differential speed is the actual speed obtained by the acquisition device 122, and this actual speed may fluctuate around the set speed. Measurement errors of the acquisition device 122 or control deviations of the dynamometer 121 may cause a mismatch between the actual speed and the set speed. The differential speed can be aligned with the set speed by adjusting the equipment on the oil level test bench 120.

[0060] In some embodiments, during the oil level test, the main control device 123 conducts the test by controlling the amount of lubricating oil added under set operating conditions. For example, by keeping factors such as temperature constant, and based on the normal oil level, it collects data on the changes in the electric drive assembly 111 when the amount added increases by 0.5L. Where the amount added is fixed, the main control device 123 adjusts the set speed, collects the differential torque and differential speed, and then generates a speed-torque curve at the current oil level. The speed-torque curve can characterize the oil filling situation, such as whether the amount added is too much or too little, by observing the speed-torque curves at different oil levels.

[0061] Optionally, the speed-torque curve graph may include multiple speed-torque curves, with different speed-torque curves representing the changes in speed and torque under different lubricant filling amounts.

[0062] For example, Figure 2This is an exemplary example of the speed-torque curve provided in this application. At an oil temperature of 80°C, the torque with normal oil volume and the torque after adding 0.5L show different torque change trends at different speeds. At the same temperature and speed, a torque change exceeding 30% indicates that the lubricating oil volume is too high, requiring a reduction in the lubricating oil volume.

[0063] Optionally, the speed-torque curve may also include speed-torque curves at different temperatures, or speed-torque curves at different pressures; this application does not limit this.

[0064] In summary, in this embodiment of the application, when the motor and differential are located in the same cavity, it is difficult to add equipment for measuring differential speed and differential torque inside the cavity. The main control equipment of the oil level test bench controls the dynamometer of the oil level test bench to mechanically drive the differential of the electric drive assembly, without having to drive the motor through the motor controller and then drive the differential, thus avoiding high voltage damage to the motor controller. The acquisition equipment on the oil level test bench can measure the differential speed and differential torque outside the cavity, solving the problem that the oil level test bench is difficult to measure the torque of the integrated electric drive assembly.

[0065] In some embodiments, the differential includes planetary gears and axle gears. The axle gears are connected to the drive shaft, ensuring that their rotation matches the rotation of the wheels during vehicle movement. The planetary gears are located between the axle gears and can revolve and rotate according to the rotation of the axle gears. The rotation of the planetary gears eliminates the speed difference between the axle gears, allowing the wheels on both sides to roll at different speeds when turning.

[0066] For example, Figure 3 A cross-sectional schematic diagram of the differential is shown. The differential 301 contains two opposing half-shaft gears, namely the first half-shaft gear 302 and the second half-shaft gear 303. The first planetary gear 304 and the second planetary gear 305 mesh with both the first half-shaft gear 302 and the second half-shaft gear 303.

[0067] When the first half-shaft gear 302 and the second half-shaft gear 303 rotate in the same direction, the first planetary gear 304 and the second planetary gear 305 revolve in the same direction, following the first half-shaft gear 302 and the second half-shaft gear 303. When the rotational speeds of the first half-shaft gear 302 and the second half-shaft gear 303 are different, the first planetary gear 304 and the second planetary gear 305 eliminate the speed difference through their own rotation. Specifically, the first planetary gear 304 and the second planetary gear 305 revolve in the same direction, but rotate in opposite directions.

[0068] In some embodiments, when the half-shaft gears of the differential are rotated synchronously by the dynamometer, the ring gear of the differential housing drives the input shaft outside the differential, thereby driving other components inside the electric drive assembly. The input shaft is used to input the power generated by the motor inside the electric drive assembly into the differential during vehicle operation.

[0069] However, the rotational ability of the planetary gears can interfere with the half-shaft gears of the dynamometer drive differential. When the dynamometer drives a single half-shaft gear to rotate, that half-shaft gear drives the planetary gears to rotate, which in turn drives the opposite half-shaft gear to rotate in the opposite direction. This makes it difficult for the dynamometer to input power to other components in the electric drive assembly, thus leading to torque measurement failure.

[0070] For example, Figure 4 A schematic diagram of the gear rotation inside the differential is shown. The dynamometer drives the first half-shaft gear 401 to rotate in the direction of the first planetary gear 402. Then, the first half-shaft gear 401 drives the first planetary gear 402 to rotate in the direction of the first half-shaft gear 401, and drives the second planetary gear 403 to rotate in the direction of the second half-shaft gear 404. The first planetary gear 402 and the second planetary gear 403 drive the second half-shaft gear 404 to rotate in the direction of the second planetary gear 403, that is, in the opposite direction to the first half-shaft gear 401, causing the differential to fail to transmit power to the input shaft 405.

[0071] To ensure synchronized rotation of the differential's half-shaft gears, the oil level test bench can employ two motors or two dynamometers to drive the two half-shaft gears synchronously. An oil level test bench with only a single motor or dynamometer would be unsuitable for measuring torque.

[0072] To avoid adding an extra motor or dynamometer, in this embodiment, the planetary gears and half-shaft gears of the differential are welded and fixed together at at least two meshing positions to prevent the planetary gears from rotating on their own, so that when a single dynamometer drives a single half-shaft gear to rotate, the half-shaft gears of the differential rotate synchronously at the same speed.

[0073] Optionally, the differential may include two or four planetary gears.

[0074] In some embodiments, the differential includes a first planetary gear, a second planetary gear, a first half-shaft gear, and a second half-shaft gear. The planetary gears and half-shaft gears of the differential are welded together at at least two meshing points, such as... Figure 5 As shown, at least two of the following cases are included:

[0075] Case 1: The first planetary gear 511 and the first half-shaft gear 512 are welded and fixed at the first meshing position 501.

[0076] Case 2: The first planetary gear 511 and the second half-shaft gear 513 are welded and fixed at the second meshing position 502.

[0077] Case 3: The second planetary gear 514 and the first half-shaft gear 512 are welded and fixed at the third meshing position 503.

[0078] Case 4: The second planetary gear 514 and the second half-shaft gear 513 are welded and fixed at the fourth meshing position 504.

[0079] With the planetary gears and axle gears welded and fixed in the meshing position, the first axle gear 512 and the second axle gear 513 rotate at the same speed toward the second planetary gear 514. The first planetary gear 511 and the second planetary gear 514 revolve in the same direction and at the same speed.

[0080] In other embodiments, the differential includes a first planetary gear, a second planetary gear, a third planetary gear, a fourth planetary gear, a first half-shaft gear, and a second half-shaft gear. The planetary gears and half-shaft gears of the differential are welded together at at least two meshing positions, including at least two of the following cases:

[0081] Case 1: The first planetary gear and the first half-shaft gear are welded and fixed at the first meshing position.

[0082] Case 2: The first planetary gear and the second half-shaft gear are welded and fixed at the second meshing position.

[0083] Case 3: The second planetary gear and the first half-shaft gear are welded and fixed at the third meshing position.

[0084] Case 4: The second planetary gear and the second half-shaft gear are welded and fixed at the fourth meshing position.

[0085] Case 5: The third planetary gear and the first half-shaft gear are welded and fixed at the fifth meshing position.

[0086] Case 6: The third planetary gear and the second half-shaft gear are welded and fixed at the sixth meshing position.

[0087] Case 7: The fourth planetary gear and the first half-shaft gear are welded and fixed at the seventh meshing position.

[0088] Case 8: The fourth planetary gear and the second half-shaft gear are welded and fixed at the eighth meshing position.

[0089] In some embodiments, the differential is installed into the cavity containing the motor after the planetary gears and half-shaft gears are welded and fixed together. There is no additional space within this cavity to install devices for measuring torque and speed.

[0090] In this embodiment, the planetary gears and axle gears are fixed together by welding. By preventing the planetary gears from rotating, the differential's ability to adjust the speed difference between different axle gears is limited. When a single dynamometer drives a single axle gear, the different axle gears rotate in the same direction at the same speed, solving the problem of different axle gears rotating in opposite directions. This allows the differential torque measured under dynamometer-driven conditions to also characterize the internal resistance of the electric drive assembly, improving the accuracy of the speed-torque curve.

[0091] In some embodiments, since dynamometers are generally used to measure motor power, while embodiments of this application require the dynamometer to drive the half-shaft gears of the differential, a mismatch in connection positions is likely to occur when the differential and the dynamometer are connected.

[0092] In electric vehicles, the differential's half-shaft gears are connected to the drive shaft, which in turn connects to the wheels. During vehicle operation, the differential first transmits power to the drive shaft, which then drives the wheels.

[0093] During the oil level test, the differential's half-shaft gears are connected to the drive shaft to simulate the transmission effect during vehicle operation. In this embodiment, the drive shaft is considered part of the differential, illustrating the connection method between the differential and the dynamometer. Since the dynamometer's speed output end is fixed with bolts, and the drive shaft's connection end is nested, a connecting fixture is required between the dynamometer's speed output end and the differential's drive shaft.

[0094] In this embodiment, the dynamometer and the differential are connected by a connecting fixture. The first connecting end of the connecting fixture is connected to the drive shaft of the differential, and the second connecting end of the connecting fixture is connected to the speed output end of the dynamometer.

[0095] For example, Figure 6 A schematic diagram of the drive shaft connection fixture is shown. The first connecting end 601 of the drive shaft connection fixture is fitted into the drive shaft of the differential. The second connecting end 602 of the drive shaft connection fixture has eight bolt connection positions, and bolts 603 connect the second connecting end 602 to the speed output end of the dynamometer.

[0096] In some embodiments, a flange is a component used for connecting shafts, and a torque flange can serve as a connector while simultaneously measuring torque.

[0097] Optionally, the dynamometer's speed output end is equipped with a torque flange, which is used to measure the differential torque and is a data acquisition device on the oil level test bench.

[0098] The first connecting end of the connecting fixture is equipped with a drive shaft connector, and the second connecting end of the connecting fixture is equipped with a flange connector. The drive shaft connector is used to connect the drive shaft, and the flange connector is used to connect the torque flange.

[0099] Optionally, the torque flange is provided with at least two holes, and the flange connector may include at least two bolts that pass through at least two holes of the torque flange, so that the torque flange is connected to the connecting fixture.

[0100] It should be noted that the shape of the connecting fixture can be changed according to the connection method of the drive shaft and the connection method of the torque flange or the speed output end of the dynamometer, so that the first connecting end of the connecting fixture conforms to the connection method of the drive shaft of the differential, and the second connecting end of the connecting fixture conforms to the connection method of the speed output end of the dynamometer, or conforms to the connection method of the torque flange on the dynamometer.

[0101] In some embodiments, the speed and torque at various points on the drive shaft between the differential's half-shaft gear and the speed output end of the dynamometer can be considered as the differential speed and differential torque. Optionally, speed sensors can be installed at various points on the drive shaft to measure the differential speed. This speed sensor is a data acquisition device on an oil level test bench.

[0102] Optionally, in addition to using a torque flange to measure the differential torque, torque sensors can be installed at other locations on the driveshaft to measure the differential torque. This torque sensor is a data acquisition device on an oil level test bench.

[0103] Considering that using a large-range sensor to measure differential torque can easily produce excessive measurement errors and reduce the accuracy of differential torque, in order to improve the accuracy of differential torque, the accuracy of the torque flange in this embodiment is higher than 0.02, and the range of the torque flange is not greater than twice the theoretical torque measurement value.

[0104] Optionally, the accuracy of the torque flange can be determined by referring to the torque measured on a standard torque flange. Alternatively, the accuracy of the torque flange can also be determined by measuring a standard torque.

[0105] For example, Figure 7 A schematic diagram of a dynamometer connected to a differential is shown in an exemplary embodiment of this application. The differential 701's half-shaft gear 702 is connected to a drive shaft 703, which is connected to a torque flange 706 on the dynamometer 705 via a connecting fixture 704.

[0106] In this embodiment, by adding a connecting fixture between the dynamometer and the drive shaft of the differential, the problem of interface mismatch between the dynamometer and the drive shaft is solved. This allows the dynamometer to drive the drive shaft to rotate the half-shaft gear of the differential, ensuring that the speed and torque between the speed output end of the dynamometer and the half-shaft gear of the differential are consistent, which is beneficial to improving the accuracy of the differential torque.

[0107] The first connecting end of the connecting fixture is connected to the drive shaft via a drive shaft connector, and the second connecting end of the connecting fixture is connected to the torque flange via a flange connector. This not only improves the connection reliability but also enables the measurement of differential torque without changing the differential connection structure. By simulating the differential connection structure under normal vehicle driving conditions, i.e., the differential half-shaft gear is connected to the drive shaft, and the other end of the drive shaft is used as the power output end (the end that drives the wheel), the differential torque is measured to obtain a differential torque that matches the actual application scenario.

[0108] Furthermore, in this embodiment, the accuracy of the differential torque is further improved by limiting the precision and range of the torque flange.

[0109] During the connection of the differential's driveshaft to the torque flange, the driveshaft needs to be aligned with the connection position of the torque flange. Since the torque flange is located on a dynamometer, and the dynamometer is located on an oil level test bench, the height of the differential's driveshaft needs to be the same as the torque flange and aligned with the holes on the torque flange.

[0110] In some embodiments, the electric drive support fixture is also used to adjust the spatial position of the electric drive assembly to align the drive shaft with the torque flange. Adjusting the spatial position may include adjusting the horizontal position and the height of the electric drive assembly.

[0111] Optionally, the electric drive support fixture includes a support leg, a first directional guide rail, a second directional guide rail, and a suspension fixture. The suspension fixture is used to connect the electric drive assembly, and the first and second directional guide rails are used to adjust the horizontal position of the electric drive assembly. The first directional guide rail is used to adjust the position of the electric drive assembly in a first direction, and the second directional guide rail is used to adjust the position of the electric drive assembly in a second direction.

[0112] For example, Figure 8 A schematic diagram of an electrically driven support fixture provided in an exemplary embodiment of this application is shown.

[0113] The support leg 800 is used to support the first direction guide rail, the first direction guide rail is used to support the second direction guide rail, the second direction guide rail supports the suspension fixture, and the suspension fixture is connected to the electric drive assembly.

[0114] The suspension fixture includes a front suspension fixture 805, a left suspension fixture 806, and a right suspension fixture 807. The electrically driven support fixture has a first directional guide rail 801, a first directional guide rail 802, a second directional guide rail 803, and a second directional guide rail 804. The left suspension fixture 806 and the right suspension fixture 807 are located on the second directional guide rail 803, and the front suspension fixture 805 is located on the second directional guide rail 804. By adjusting the tightness of the bolts on the first and second directional guide rails, the sliding and fixing of the second directional guide rails and the suspension fixtures can be achieved.

[0115] The suspension fixture is used to simulate the connection method of the electric drive assembly on the vehicle, that is, to connect the electric drive assembly to the cushion assembly, and to connect the cushion assembly to the suspension fixture. The cushion assembly includes a front suspension cushion assembly, a left suspension cushion assembly, and a right suspension cushion assembly. Specifically, the front suspension cushion assembly is connected to the front suspension fixture 805, the left suspension cushion assembly is connected to the left suspension fixture 806, and the right suspension cushion assembly is connected to the right suspension fixture 807.

[0116] The support leg 800 is used to adjust the height. The first direction guide rail is used to allow the second direction guide rail to slide along the first direction, and the second direction guide rail is used to allow the suspended fixture to slide along the second direction.

[0117] Wherein, the first direction is horizontal and the second direction is vertical, or the second direction is horizontal and the first direction is vertical.

[0118] The first direction guide rail 801 and the first direction guide rail 802 are used to allow the second direction guide rail 803 and the second direction guide rail 804 to slide in the first direction. The second direction guide rail 803 is used to allow the left suspension fixture 806 and the right suspension fixture 807 to slide in the second direction. The second direction guide rail 804 is used to allow the front suspension fixture 805 to slide in the second direction.

[0119] For example, Figure 9 A schematic diagram showing the connection between the electric drive assembly and the electric drive support fixture is provided. The electric drive assembly is fixed to the electric drive support fixture via a suspension fixture. Four support feet 900 are used to adjust the height of the differential's drive shaft 910. First directional guide rails 901 and 902 are used to move the electric drive assembly horizontally so that the drive shaft 910 is aligned with the speed output end of the dynamometer. Second directional guide rails 903 and 904 are used to adjust the electric drive assembly to move towards the dynamometer so that the drive shaft 910 is connected to the speed output end of the dynamometer.

[0120] In this embodiment, the electric drive support fixture is connected to the electric drive assembly via a suspension fixture. The position of the electric drive assembly in the horizontal direction is adjusted by two vertical guide rails, so that the transmission shaft of the differential is connected to the speed output end of the dynamometer, ensuring the spatial position of the electric drive assembly is stable.

[0121] Figure 10 This is a schematic diagram illustrating the connection between an electric drive assembly and an oil level test bench according to another exemplary embodiment of this application. The oil level test bench of the system also includes a lubricating oil injection assembly 1001 and a temperature control assembly 1002. The main control device 1003 is connected to the lubricating oil injection assembly 1001 and the temperature control assembly 1002.

[0122] The main control device 1003 is used to control the lubricating oil injection component 1001 to inject a set amount of lubricating oil into the cavity of the electric drive assembly.

[0123] For example, the main control device 1003 first sets the reference oil volume, and then adds 0.5L of oil each time based on the reference oil volume. That is, when the reference oil volume is 20L, the set amount of lubricating oil is determined in the order of 20L, 20.5L, 21L, 21.5L, 22L...

[0124] The main control device 1003 is also used to control the temperature control component 1002 to heat the lubricating oil to a set temperature so as to generate speed and torque curves at different lubricating oil temperatures.

[0125] In some possible test scenarios, the main control device 1003 determines the set temperature at fixed intervals. For example, the main control device 1003 determines the set temperature in the order of 70℃, 75℃, 80℃, 85℃...

[0126] In one possible implementation, the main control device first determines the set temperature, and then generates speed-torque curves for different amounts of lubricating oil at that set temperature.

[0127] The main control device 1003 is also used to receive the temperature and pressure of cooling water or lubricating oil collected by the acquisition device 1004. Specifically, when the temperature of the lubricating oil is higher than the set temperature, the temperature control component 1002 is controlled to lower the temperature of the lubricating oil; when the temperature of the lubricating oil is lower than the set temperature, the temperature control component 1002 is controlled to raise the temperature of the lubricating oil, so that the oil temperature inside the cavity of the electric drive assembly is stabilized at the set temperature.

[0128] The main control device 1003 is also used to control the dynamometer 1005 to drive the differential half-shaft gear to rotate at a set speed.

[0129] In this embodiment, the main control device controls the lubricating oil injection component to inject a set amount of lubricating oil into the cavity of the electric drive assembly, and generates a speed-torque curve after heating to a set temperature. This yields speed-torque curves under different temperatures and lubricating oil injection amounts. By controlling the influencing factors of the speed-torque curves, multiple speed-torque curves under different electric drive assembly operating conditions are obtained, improving the comprehensiveness of the speed-torque curve information and facilitating the determination of the optimal lubricating oil injection amount.

[0130] In some possible test scenarios, the main control device gradually increases or decreases the set speed at fixed intervals, and receives the differential speed and differential torque collected by the acquisition device, thereby generating a speed-torque curve based on the differential speed and differential torque.

[0131] During the process of the dynamometer output speed increasing or decreasing according to the set speed, the main control equipment needs to wait for the dynamometer output speed (i.e., the differential speed) to reach the set speed and remain stable. Optionally, the main control equipment can ensure that the differential speed can be stabilized at the set speed by setting a fixed waiting time.

[0132] For example, when the set speed is adjusted from 1000 rpm to 2000 rpm, the main control device first waits for the differential speed to reach 2000 rpm, and then waits for the differential speed to stabilize at the set speed while the differential fluctuates around 2000 rpm.

[0133] In some embodiments, the main control device is further configured to collect the differential speed and differential torque when the driving time of the dynamometer driving the differential at a set speed reaches a time threshold.

[0134] Optionally, the drive duration can be the duration for which the dynamometer maintains the set speed while driving the differential.

[0135] For example, with a set speed of 2000 rpm and a duration threshold of 30 seconds, the main control device first sends a drive command to the dynamometer to drive the differential at 2000 rpm, then collects the differential speed. If the differential speed remains at 2000 rpm for 30 seconds, the main control device then sends a drive command to the dynamometer to drive the differential at 3000 rpm, again collecting the differential speed. If the differential speed remains at 3000 rpm for 30 seconds, the main control device collects both the differential speed and differential torque. Subsequently, the main control device sends a drive command to the dynamometer to drive the differential at 4000 rpm, again collecting the differential speed. If the differential speed remains at 4000 rpm for 30 seconds, the main control device collects both the differential speed and differential torque. This process is repeated.

[0136] Optionally, the drive duration can also be the time the main control device waits for the dynamometer to adjust the speed each time.

[0137] For example, with a set speed of 2000 rpm and a time threshold of 30 seconds, the main control device first controls the dynamometer to drive the differential at 2000 rpm, and then collects the differential speed and torque at 30 seconds. The main control device then controls the dynamometer to drive the differential at 3000 rpm, and collects the differential speed and torque at 60 seconds. Then, it drives the differential at 4000 rpm, and collects the differential speed and torque at 90 seconds. This process is repeated.

[0138] This application embodiment illustrates the method by which the main control device collects differential speed and differential torque, ensuring that the differential speed is stable at the set speed, so as to fix the speed sampling interval, improve the reliability of the speed-torque curve, and facilitate the comparison of different speed-torque curves to determine the accurate amount of lubricating oil to be added.

[0139] Figure 11 A flowchart of an oil level testing method provided in an exemplary embodiment of this application is shown. This method is used in the main control device of the various embodiments described above. The method includes the following steps.

[0140] Step 1101: Send a drive command to the dynamometer. The drive command is used to instruct the dynamometer to drive the half-shaft gear of the differential to rotate based on the set speed.

[0141] In one possible implementation, the master control device sends drive commands indicating set speeds to the dynamometer according to a set speed sequence. For example, if the set speed sequence is 2000 rpm, 3000 rpm, and 4000 rpm, the master control device first sends a drive command indicating 2000 rpm to the dynamometer, then sends a drive command indicating 3000 rpm, and finally sends a drive command indicating 4000 rpm.

[0142] In another possible implementation, the main control device adjusts the set speed at fixed speed intervals, and then sends a drive command to the dynamometer indicating the set speed. For example, the main control device first increases 1000 rpm by 1000 rpm and sends a drive command to the dynamometer indicating 2000 rpm, then increases 2000 rpm by 1000 rpm and sends a drive command to the dynamometer indicating 3000 rpm.

[0143] Optionally, the main control device can send drive commands to the dynamometer at fixed time intervals.

[0144] In one possible implementation, the main control device first sends a first drive command to the dynamometer, which instructs the dynamometer to drive the half-shaft gear of the differential to rotate based on a first set speed. When the driving time of the dynamometer driving the differential at the first set speed reaches a time threshold, the main control device sends a second drive command to the dynamometer, which instructs the dynamometer to drive the half-shaft gear of the differential to rotate based on a second set speed.

[0145] Step 1102: During the rotation process, the differential speed and differential torque are collected by the acquisition device.

[0146] Optionally, when the driving time of the dynamometer driving the differential at a set speed reaches a time threshold, the main control device receives the differential speed and differential torque collected by the acquisition device.

[0147] In one possible implementation, the main control device receives the differential speed collected by the acquisition device in real time. When the differential speed is the set speed, the main control device counts the driving time of the dynamometer driving the differential at the set speed. Then, when the driving time reaches the duration threshold, the main control device receives the differential speed and differential torque collected by the acquisition device.

[0148] In another possible implementation, after sending a drive command to the dynamometer, the main control device waits for the dynamometer to drive the differential at the set speed. If the waiting time reaches a threshold, the main control device determines that the driving time for the dynamometer to drive the differential at the set speed has reached the threshold, and then receives the differential speed and differential torque collected by the acquisition device.

[0149] Optionally, the main control device can receive the differential speed and differential torque collected by the acquisition device in real time during the process of the dynamometer driving the differential half-shaft gear to rotate, and generate a speed-torque curve.

[0150] For example, the main control device sends drive commands indicating the set speeds to the dynamometer according to the ascending sequence of set speeds. As the differential speed gradually increases, as collected by the acquisition device, the main control device generates a speed-torque curve based on the real-time differential speed and torque.

[0151] Step 1103: Based on the differential speed and differential torque, generate a speed-torque curve under different lubricant filling amounts. The speed-torque curve is used to characterize the change of differential torque under different differential speeds.

[0152] Optionally, the main control device can receive the differential speed and differential torque in real time, and then generate a speed-torque curve based on the real-time differential speed and real-time differential torque at the current lubricating oil filling level.

[0153] Optionally, the main control device can also receive the differential speed and differential torque in real time. Then, when the differential speed meets the set speed and the driving time of the dynamometer driving the differential at the set speed reaches the time threshold, the differential speed and differential torque are sampled to obtain sample differential speed and sample differential torque. Then, based on the sample differential speed and sample differential torque, a speed-torque curve graph under the current lubricating oil filling amount is generated.

[0154] Optionally, the main control device can also receive the differential speed and differential torque collected by the acquisition device when the driving time of the differential driven by the dynamometer at the set speed reaches the time threshold, and generate a speed-torque curve under the current lubricating oil filling amount based on the received differential speed and differential torque.

[0155] Optionally, the speed-torque curves under different lubricant filling amounts can be plotted on the same speed-torque curve graph, or they can be plotted on different speed-torque curve graphs.

[0156] Figure 12 This diagram illustrates an implementation of an exemplary embodiment of the oil level testing method provided in this application. The main control device 1200 first controls the lubricating oil injection assembly 1201 to inject a set amount of lubricating oil. Then, it sends a drive command to the dynamometer 1202, causing the dynamometer 1202 to drive the half-shaft gear 1204 of the differential 1203 to rotate at the set speed indicated by the drive command. During the rotation of the half-shaft gear 1204, the main control device 1200 receives the oil temperature collected by the sampling device 1205. If the oil temperature is higher or lower than the set temperature, the main control device 1200 controls the temperature control assembly 1206 to adjust the oil temperature. The main control device 1200 receives the differential speed and differential torque collected by the sampling device 1205, and then generates a speed-torque curve under the current set amount of lubricating oil. Subsequently, the main control device 1200 controls the lubricating oil injection assembly 1201 to inject different set amounts of lubricating oil, generating speed-torque curves under different set amounts of lubricating oil.

[0157] In summary, the main control equipment of the oil level test bench has the ability to control the rotation of the half-shaft gear of the differential driven by the dynamometer. The main control equipment can also receive and collect the differential speed and torque from the acquisition equipment, which helps to improve the accuracy of the speed-torque curve. This avoids the problems of difficulty in controlling the speed and measuring the torque when the differential is driven by a motor controller. As a result, the electric drive assembly does not need to be equipped with a motor controller during the test, avoiding the possibility of high voltage damaging the motor controller and saving hardware resources.

[0158] It should be noted that the data acquisition devices involved in the embodiments of this application, such as torque flanges, temperature sensors, pressure sensors, and speed sensors, need to be calibrated before use.

[0159] Those skilled in the art will recognize that the functions described in the embodiments of this application in one or more of the above examples can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0160] The above are merely optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An electrically driven oil level testing system, characterized in that, The system includes: an electrically driven support fixture and an oil level test bench; The electric drive support fixture is used to support the electric drive assembly, which includes a motor and a differential located in the same cavity. The cavity is filled with lubricating oil, and the half-shaft gears in the differential are configured to rotate synchronously. The oil level test bench is equipped with a dynamometer, a data acquisition device, and a main control device; the dynamometer and the differential are connected by a connecting fixture; the first connecting end of the connecting fixture is connected to the drive shaft of the differential, and the second connecting end of the connecting fixture is connected to the speed output end of the dynamometer; The speed output end is provided with a torque flange, which is used to measure the torque of the differential; the first connection end of the connecting fixture is provided with a drive shaft connector, and the second connection end of the connecting fixture is provided with a flange connector. The drive shaft connector is used to connect the drive shaft, and the flange connector is used to connect the torque flange. The dynamometer is used to drive the half-shaft gear of the differential to rotate based on different set speeds; The acquisition device is used to acquire the differential speed and differential torque of the differential during rotation. The main control device is used to generate a speed-torque curve graph under different lubricating oil filling amounts based on the differential speed and the differential torque. The speed-torque curve graph is used to characterize the change of the differential torque under different differential speeds.

2. The system according to claim 1, characterized in that, The planetary gears of the differential are welded and fixed to the half-shaft gears at at least two meshing positions.

3. The system according to claim 1, characterized in that, The torque flange has an accuracy higher than 0.02, and the range of the torque flange is no more than twice the theoretical torque measurement value.

4. The system according to claim 1, characterized in that, The electric drive support fixture is also used to adjust the spatial position of the electric drive assembly so that the drive shaft is aligned with the torque flange.

5. The system according to claim 4, characterized in that, The electrically driven support fixture includes support legs, a first direction guide rail, a second direction guide rail, and a suspension fixture. The support leg is used to support the first directional guide rail, the first directional guide rail is used to support the second directional guide rail, the second directional guide rail supports the suspension fixture, and the suspension fixture is connected to the electric drive assembly; The support leg is used to adjust the height, the first directional guide rail is used to allow the second directional guide rail to slide along the first direction, and the second directional guide rail is used to allow the suspension fixture to slide along the second direction; Wherein, the first direction is horizontal and the second direction is vertical, or the second direction is horizontal and the first direction is vertical.

6. The system according to claim 1, characterized in that, The main control device is connected to the lubricating oil injection component and the temperature control component; The main control device is used to control the lubricating oil injection assembly to inject a set amount of lubricating oil into the cavity of the electric drive assembly; The main control device is also used to control the temperature control component to heat the lubricating oil to a set temperature in order to generate the speed-torque curve at different lubricating oil temperatures.

7. The system according to claim 1, characterized in that, The main control device is used to collect the differential speed and the differential torque when the driving time of the dynamometer driving the differential at the set speed reaches a time threshold.

8. A method for testing oil level in an electrically driven system, characterized in that, The method is used in the master control device of any one of the systems described in claims 1 to 7, and the method includes: Send a drive command to the dynamometer, the drive command being used to instruct the dynamometer to drive the half-shaft gear of the differential to rotate based on a set speed; During rotation, the differential speed and differential torque are collected by the receiving and acquisition equipment. Based on the differential speed and the differential torque, a speed-torque curve is generated under different lubricant filling amounts. The speed-torque curve is used to characterize the change of the differential torque under different differential speeds.

Images