Testing method of inter-axle differential

Abstract

The invention discloses a method for testing an inter-axle differential, and the method comprises the steps: obtaining corresponding test parameters under different test conditions, the test parameters at least comprising one or more of an input parameter of an intermediate axle, an output parameter of the intermediate axle, an oil temperature, test time, and test times; the test working conditions at least comprise one or more of a middle axle slip working condition, a rear axle slip working condition, a starting impact working condition and a heavy load differential working condition; controlling the working state of the wheel and / or the through shaft to be a simulation state under the corresponding test working condition; controlling the driving assembly to work according to the test parameters so as to obtain use state parameters of the inter-axle differential mechanism under different test working conditions; and determining a test result of the inter-axle differential according to the use state parameters. By adopting the method, the wear detection of the inter-axle differential can be realized through the use state parameters of the inter-axle differential.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular to a test method for an inter-axle differential. Background Art

[0002] In the related art, the inter-axle differential of the existing drive axle may have wear failures, but the wear condition of the inter-axle differential cannot be tested. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, an object of the present invention is to provide a test method for an inter-axle differential. By using this method, the wear detection of the inter-axle differential can be realized through the usage state parameters of the inter-axle differential.

[0004] To solve the above problems, a first aspect embodiment of the present invention provides a test method for an inter-axle differential for a drive assembly. The drive assembly includes an inter-axle differential, an intermediate axle, and a rear axle. The inter-axle differential is disposed in the intermediate axle, and the intermediate axle is connected to the rear axle through a through shaft. The test method includes: obtaining test parameters corresponding to different test conditions, where the test parameters include at least one or more of the input parameter of the intermediate axle, the output parameter of the intermediate axle, the oil temperature, the test time, and the number of tests; controlling the working state of the wheels and / or the through shaft to be an analog state corresponding to the test condition; controlling the drive assembly to work according to the test parameters to obtain usage state parameters of the inter-axle differential under different test conditions; and determining the test result of the inter-axle differential according to the usage state parameters.

[0005] According to the test method for the inter-axle differential of the embodiment of the present invention, by combining the operating states of the drive assembly under different test conditions to control the working states of the wheels and / or the through shaft, the operation of the drive assembly under different test conditions is simulated, and whether the inter-axle differential is worn is determined according to the usage state parameters of the inter-axle differential generated by controlling the drive assembly to work under different test conditions. Thus, the wear test of the inter-axle differential under different test conditions is realized, so that the product performance of the inter-axle differential can be fully verified in the initial stage of development, and the reliability of the vehicle after development is ensured.

[0006] In some embodiments, controlling the working state of the wheels and / or the through shaft to be an analog state corresponding to the test condition includes: controlling the working states of the wheels and the through shaft to be a first analog state under the intermediate axle slip condition, the starting impact condition, or the heavy load differential condition. The first analog state is a state in which the wheels connected to the intermediate axle rotate, the wheels connected to the rear axle stop rotating, and the flange of the through shaft stops outputting.

[0007] In some embodiments, when the test condition is the middle axle slipping condition, controlling the drive assembly to work according to the test parameters includes: controlling the middle axle to work according to the input parameters and the output parameters, wherein the input parameters of the middle axle are the first input rotational speed value and the first input torque, the output parameter of the middle axle is the first output rotational speed value, the first output rotational speed value is the running speed of the wheels connected to the middle axle, and the first output rotational speed value = 2 × the first input rotational speed value / the middle axle reduction ratio; controlling the cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the first temperature, wherein the minimum allowable operating oil temperature value ≤ the first temperature ≤ the maximum allowable operating oil temperature value; after determining that the test time for the operation of the drive assembly reaches the first preset time, controlling the drive assembly to stop working, and the first preset time ≥ 300 s.

[0008] In some embodiments, the input parameters include the input torque and the input rotational speed. When the test condition is the starting shock condition, controlling the drive assembly to work according to the test parameters includes: controlling the input torque of the middle axle to be the second input torque, and controlling the input rotational speed of the middle axle to be gradually loaded from rest to the second input rotational speed value, where the second input torque = the rated input torque of the middle axle × a, and a is less than 1; controlling the cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the second temperature, wherein the minimum allowable operating oil temperature value ≤ the second temperature ≤ the maximum allowable operating oil temperature value; after determining that the number of tests on the drive assembly reaches the preset number of times, controlling the drive assembly to stop working.

[0009] In some embodiments, when the test condition is the heavy load differential condition, controlling the drive assembly to work according to the test parameters includes: controlling the middle axle to work according to the input parameters and the output parameters, wherein the input parameters of the middle axle are the third input rotational speed value and the third input torque, the output parameter of the middle axle is the third output rotational speed value, and the third output rotational speed value is the running speed of the wheels connected to the middle axle; controlling the cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the third temperature, wherein the minimum allowable operating oil temperature value ≤ the third temperature ≤ the maximum allowable operating oil temperature value; after determining that the test time for the operation of the drive assembly reaches the third preset time, controlling the drive assembly to stop working, where the third preset time ≥ 35 h. In some embodiments, controlling the working states of the wheels and / or the through shaft to be simulated states under corresponding test conditions includes: controlling the working states of the wheels and the through shaft to be a second simulated state under the condition of rear axle slip, where the second simulated state is a state in which the wheels connected to the middle axle stop rotating, the wheels connected to the rear axle rotate, and the flange of the through shaft outputs.

[0010] In some embodiments, controlling the drive assembly to work according to the test parameters includes: controlling the middle axle to work according to the input parameters and the output parameters, where the input parameters of the middle axle are the fourth input speed value and the fourth input torque, the output parameter of the middle axle is the fourth output speed value, the fourth output speed value is the operating speed of the through shaft, and the fourth output speed value = 2 × the fourth input speed value; controlling the cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature when the drive assembly works is the fourth temperature, where the minimum allowable working oil temperature value ≤ the fourth temperature ≤ the maximum allowable working oil temperature value; after determining that the test time for the drive assembly to work reaches the second preset time, controlling the drive assembly to stop working, and the second preset time ≥ 150 s.

[0011] In some embodiments, before controlling the working states of the wheels and / or the through shaft to be simulated states under corresponding test conditions, it includes: controlling the wheels connected to the middle axle and the wheels connected to the rear axle to both stop rotating, and controlling the flange of the through shaft to stop outputting; obtaining running-in control parameters; and running in the drive assembly according to the running-in control parameters.

[0012] In some embodiments, the running-in control parameters include the input speed of the middle axle and the output speed of the middle axle. Running in the drive assembly according to the running-in control parameters includes: controlling the middle axle to work at the fifth input speed value and the fifth output speed value; and determining that the oil temperature when the drive assembly works reaches the minimum allowable working oil temperature value to complete the running-in of the drive assembly.

[0013] In some embodiments, the inter-axle differential includes a cross shaft, planetary gears, planetary gear shims, and an inter-axle differential housing. Determining the test result of the inter-axle differential according to the usage state parameters includes: if the usage state parameters meet the preset wear conditions, determining that the test result of the inter-axle differential is worn; where the preset wear conditions include at least any one of the following: the output torque of the middle axle is higher than the preset torque threshold; the cross shaft and the planetary gears cannot rotate relative to each other; there is a sintering phenomenon in the inter-axle differential; the wear marks of the cross shaft and the planetary gears are higher than 1 / 2 × the mating length; the maximum wear mark depth of the cross shaft and the planetary gears is higher than the preset wear mark depth; the wear amount of the planetary gear shims is higher than the first preset wear amount; the wear amount of the inter-axle differential housing is higher than the second preset wear amount.

[0014] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, where: Figure 1 is a test method for an inter-axle differential according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the drawings are exemplary. The embodiments of the present invention will be described in detail below.

[0017] In the existing driving axle industry standard QC / T 533, there is no bench test standard related to the inter-axle differential. Usually, the bench test is carried out by referring to the method of the wheel differential. However, referring to the relevant standards of the wheel differential for the bench test has incomplete working conditions and does not consider the extreme slip working conditions and the starting impact or reverse towing working conditions.

[0018] To solve the above problems, the first aspect embodiment of the present invention provides a test method for an inter-axle differential for a drive assembly. By using this method, the wear detection of the inter-axle differential can be realized through the usage state parameters of the inter-axle differential.

[0019] In the embodiment, the drive assembly includes an inter-axle differential, a middle axle, and a rear axle. The inter-axle differential is arranged in the middle axle, and the middle axle is connected to the rear axle through a through shaft.

[0020] The following refers to Figure 1 Describe the test method for the inter-axle differential according to the embodiment of the present invention. As Figure 1 shown, the method includes steps S1 - step S4.

[0021] Step S1, obtain the test parameters corresponding to different test conditions. The test parameters include at least one or more of the input parameters of the middle axle, the output parameters of the middle axle, the oil temperature, the test time, and the number of test times. The test conditions include at least one or more of the middle axle slip condition, the rear axle slip condition, the starting shock condition, and the heavy load differential condition.

[0022] Among them, the input parameters of the middle axle can be understood as the parameters of the experimental motor for controlling the operation of the middle axle. The output parameters of the middle axle can be understood as the output parameters of the middle axle that can achieve the differential effect setting of the inter-axle differential. The oil temperature is the temperature of the lubricating oil of the drive assembly. The test time is the duration of the wear test on the inter-axle differential. The number of test times is the number of working times during the wear test on the inter-axle differential.

[0023] Specifically, the user can input the test parameters corresponding to different test conditions through the control panel of the test bench. Among them, the test parameters are the values set according to the operating parameters of the drive assembly under the test conditions, and the test bench can obtain the test parameters corresponding to different test conditions.

[0024] Step S2, control the working state of the wheels and / or the through shaft to the simulated state under the corresponding test conditions.

[0025] Specifically, combine the operating conditions of the wheels and / or the through shaft under the middle axle slip condition, the rear axle slip condition, the starting shock condition, and the heavy load differential condition to control the working state of the wheels and / or the through shaft, so as to simulate the middle axle slip condition, the rear axle slip condition, the starting shock condition, and the heavy load differential condition.

[0026] Step S3, control the drive assembly to work according to the test parameters to obtain the usage state parameters of the inter-axle differential under different test conditions.

[0027] Among them, the usage state parameters can be understood as the parameters that can reflect the usage state of the inter-axle differential under different test conditions. The usage state parameters can be the wear amount, wear marks, etc. of the inter-axle differential.

[0028] Specifically, control the drive assembly to work according to the test parameters set according to the operating parameter conditions of the drive assembly under the test conditions to obtain the usage state parameters of the inter-axle differential under different test conditions.

[0029] Step S4, determine the test result of the inter-axle differential according to the usage state parameters.

[0030] Specifically, the test result of the inter-axle differential is determined according to the usage status parameters, that is, whether the inter-axle differential is worn is determined according to the usage status parameters of the inter-axle differential under different test conditions. That is to say, the usage status parameters obtained after the wear test of the inter-axle differential under different test conditions are compared with the preset usage status parameters when the inter-axle differential is in a worn state. If the two are consistent, it means that the test result of the inter-axle differential is worn. On the contrary, if the two are inconsistent, it means that the test result of the inter-axle differential is not worn. For example, if the wear amount of the inter-axle differential is consistent with the preset wear amount when the inter-axle differential is in a worn state, it means that the inter-axle differential is worn. Thus, in this application, the wear test of the inter-axle differential under different test conditions is realized through the usage status parameters of the inter-axle differential, so that the product performance of the inter-axle differential can be fully verified in the initial stage of development, and the reliability of the vehicle after development can be guaranteed.

[0031] According to the test method of the inter-axle differential according to the embodiment of the present invention, combined with the operating state of the drive assembly under different test conditions, the working state of the wheels and / or the through shaft is controlled, so as to simulate the operation of the drive assembly under different test conditions, and whether the inter-axle differential is worn is determined according to the usage status parameters of the inter-axle differential generated by controlling the drive assembly to work according to the test parameters under different test conditions. Thus, the wear test of the inter-axle differential under different test conditions is realized, so that the product performance of the inter-axle differential can be fully verified in the initial stage of development, and the reliability of the vehicle after development can be guaranteed.

[0032] In some embodiments, controlling the working state of the wheels and / or the through shaft to be the simulated state under the corresponding test conditions includes: controlling the working state of the wheels and the through shaft to be the first simulated state under the medium bridge slip condition or the starting impact condition or the heavy load differential condition, and the first simulated state is the state where the wheels connected to the medium bridge rotate, the wheels connected to the rear bridge stop rotating, and the flange of the through shaft stops outputting.

[0033] Specifically, since the rear bridge is in a fixed state when the medium bridge slips, so that the medium bridge is in an idling state and the rear bridge is in a fixed state. Therefore, when conducting the wear test of the inter-axle differential under the medium bridge slip condition, the working state of the wheels and the through shaft is controlled to be the first simulated state. Since the flange of the through shaft stops outputting, the power of the medium bridge cannot be transmitted to the rear bridge, so the wheels connected to the rear bridge stop rotating. At this time, the wheels connected to the medium bridge rotate idly, thus realizing the simulation of the medium bridge slip condition, and being able to conduct the wear test of the inter-axle differential under the medium bridge slip condition.

[0034] Moreover, under the starting impact condition or the heavy-load differential condition, in order to reduce the resistance of the bench test stand, the through-shaft flange is controlled to stop outputting, and the power of the middle bridge cannot be transmitted to the rear bridge. Therefore, the wheels connected to the rear bridge stop rotating, that is, the state of controlling the wheels connected to the middle bridge to rotate, the wheels connected to the rear bridge to stop rotating, and the through-shaft flange to stop outputting is realized, thereby simulating the starting impact condition or the heavy-load differential condition.

[0035] In some embodiments, during the wear test, the inter-axle differential needs to be in the locked state, that is, the inter-axle differential is in the working state to conduct the experiment.

[0036] In some embodiments, when the test condition is the middle-bridge slip condition, the drive assembly is controlled to work according to the test parameters, including: controlling the middle bridge to work according to the input parameters and the output parameters. Among them, the input parameters of the middle bridge are the first input speed value and the first input torque, the output parameter of the middle bridge is the first output speed value, the first output speed value is the running speed of the wheels connected to the middle bridge, and the first output speed value = 2 × the first input speed value / the middle-bridge reduction ratio; controlling the cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the first temperature, where the minimum allowable working oil temperature value ≤ the first temperature ≤ the maximum allowable working oil temperature value; after determining that the test time for the operation of the drive assembly reaches the first preset time, controlling the drive assembly to stop working, and the first preset time ≥ 300 s.

[0037] Among them, the first input torque of the middle bridge is provided by the test motor, and the first input torque, the first input speed value, and the first output speed value are set through the bench test stand. Exemplarily, the first input speed value can be converted according to the instrument vehicle speed of 40 Km / h, and the first input torque can be set to 100 Nm. The minimum allowable working oil temperature value is 60 °C, and the maximum allowable working oil temperature value is 120 °C. Specifically, to simulate the skidding condition of the middle bridge, the user sets the first input rotational speed value, the first input torque, and the first output rotational speed value of the middle bridge through the control panel of the bench test stand according to the operating conditions of the input parameters of the middle bridge under this condition, so as to control the operation of the middle bridge based on the first input rotational speed value, the first input torque, and the first output rotational speed value of the middle bridge. At the same time, the oil temperature of the drive assembly during the actual driving of the vehicle needs to be within a certain range to ensure the lubrication performance, and the lubrication performance will affect the wear condition of the inter-axle differential. Then, the cooling device connected to the drive assembly is controlled to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the first temperature, that is, to control the first temperature to be between the minimum allowable operating oil temperature value and the maximum allowable operating oil temperature value, thereby simulating the wear state of the inter-axle differential during the actual driving of the vehicle. When it is determined that the test time of the drive assembly operation reaches the first preset time, the first preset time is the minimum time that can test whether the inter-axle differential is worn under the skidding condition of the middle bridge. That is to say, if the test time of the drive assembly operation reaches the first preset time and the wear test of the inter-axle differential can be completed, then the drive assembly is controlled to stop working. Based on this, it is determined whether the inter-axle differential is worn according to the usage state parameters of the inter-axle differential under the skidding condition of the middle bridge. That is to say, the usage state parameters of the inter-axle differential under the skidding condition of the middle bridge are compared with the preset usage state parameters when the inter-axle differential is in a worn state. If the two are the same, it means that the test result of the inter-axle differential is worn. On the contrary, if the two are different, it means that the test result of the inter-axle differential is not worn. For example, when controlling the operation of the middle bridge according to the first input rotational speed value, the first input torque, and the first output rotational speed value of the middle bridge, the obtained usage state parameter of the inter-axle differential is the first output torque of the middle bridge. Whether the inter-axle differential is worn is judged by the first output torque of the middle bridge. If the first output torque is the same as the preset torque when the inter-axle differential is in a worn state, it is determined that the inter-axle differential is worn; otherwise, it is confirmed that the inter-axle differential is not worn.

[0038] In addition, it should be noted that the first output torque of the middle bridge can be measured by a sensor or calculated by the following calculation formula: The first output torque = the first input torque × the middle bridge reduction ratio × the transmission efficiency / the middle and rear axle torque distribution coefficient.

[0039] Among them, the first input torque can be 100 Nm, the transmission efficiency can be 0.97, and the middle and rear axle torque distribution coefficient can be 2. Setting the middle and rear axle torque distribution coefficient to 2 means that the middle and rear axle torques are equally divided.

[0040] In some embodiments, the input parameters include the input torque and the input rotational speed. When the test condition is the starting shock condition, the operation of the drive assembly is controlled according to the test parameters, including: controlling the input torque of the intermediate axle to be the second input torque, and controlling the input rotational speed of the intermediate axle to be gradually loaded from rest to the second input rotational speed value, where the second input torque = the rated input torque of the intermediate axle × a, and a is less than 1; controlling the cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the second temperature, where the minimum allowable operating oil temperature value ≤ the second temperature ≤ the maximum allowable operating oil temperature value; after determining that the number of tests on the drive assembly reaches the preset number of times, controlling the drive assembly to stop operating.

[0041] Among them, the second input rotational speed value can be set to 20 rpm, and a can be 80%. The preset number of times can be 2000 times, and the second input torque can be set to 80% of the rated input torque at the input end of the intermediate axle.

[0042] Specifically, in order to simulate the starting shock condition, the user sets the input torque and the input rotational speed of the intermediate axle through the control panel of the test bench according to the operating conditions of the input parameters and the output parameters of the intermediate axle under this condition, so as to control the input torque of the intermediate axle to be the second input torque, and control the input rotational speed of the intermediate axle to be gradually loaded from rest to the second input rotational speed value to control the operation of the intermediate axle. At the same time, the oil temperature of the drive assembly during the actual driving of the vehicle needs to be within a certain range to ensure the lubrication performance, and the lubrication performance will affect the wear condition of the inter-axle differential. Then, control the cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the second temperature, that is, control the second temperature to be between the minimum allowable operating oil temperature value and the maximum allowable operating oil temperature value, so as to simulate the wear state of the inter-axle differential during the actual driving of the vehicle. When it is determined that the number of tests on the drive assembly reaches the preset number of times, it means that it can be tested whether the inter-axle differential is worn under the starting shock condition, and then control the drive assembly to stop operating.

[0043] Based on this, the wear state of the inter-axle differential is determined according to the usage state parameters of the inter-axle differential under the starting impact condition. That is to say, the usage state parameters of the inter-axle differential under the starting impact condition are compared with the preset usage state parameters when the inter-axle differential is in a worn state. If the two are consistent, it indicates that the test result of the inter-axle differential is worn. On the contrary, if the two are inconsistent, it indicates that the test result of the inter-axle differential is not worn. For example, the input torque of the middle axle is controlled to be the second input torque, and the input speed of the middle axle is gradually loaded from rest to the second input speed value to control the middle axle to work. At this time, the usage state parameter of the inter-axle differential obtained is the second output torque of the middle axle. Whether the inter-axle differential is worn is judged by the second output torque of the middle axle. If the second output torque is consistent with the preset torque when the inter-axle differential is in a worn state, it is determined that the inter-axle differential is worn; otherwise, it is determined that the inter-axle differential is not worn.

[0044] In addition, it should be noted that the second output torque can be measured by a torque sensor or calculated by the following formula: Second output torque = Second input torque × Middle axle reduction ratio × Transmission efficiency / Middle and rear axle torque distribution coefficient.

[0045] Among them, the transmission efficiency is 0.97, and the middle and rear axle torque distribution coefficient can be 2. Setting the middle and rear axle torque distribution coefficient to 2 means that the middle and rear axle torques are equally divided.

[0046] In some embodiments, when the test condition is a heavy load differential condition, the drive assembly is controlled to work according to the test parameters, including: controlling the middle axle to work according to the input parameters and output parameters. Among them, the input parameters of the middle axle are the third input speed value and the third input torque, and the output parameter of the middle axle is the third output speed value, and the third output speed value is the running speed of the wheel connected to the middle axle; controlling the cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature when the drive assembly works is the third temperature, where the minimum allowable working oil temperature value ≤ the third temperature ≤ the maximum allowable working oil temperature value; after determining that the test time for the drive assembly to work reaches the second preset time, controlling the drive assembly to stop working, where the third preset time ≥ 35h.

[0047] Specifically, to simulate the heavy-duty differential condition, the user sets the input torque and input speed of the intermediate axle through the control panel of the test bench according to the operating conditions of the input parameters and output parameters of the intermediate axle under this condition, so as to control the input torque of the intermediate axle to be the third input torque, the input speed of the intermediate axle to be the third input speed value, and the output speed of the intermediate axle to be the third output speed value. Among them, the third input torque, the third input speed value, and the third output speed value are defined according to the QC / T533 standard to control the operation of the intermediate axle. At the same time, the oil temperature of the drive assembly needs to be within a certain range during the actual driving of the vehicle to ensure the lubrication performance, and the lubrication performance will affect the wear condition of the inter-axle differential. Then, the cooling device connected to the drive assembly is controlled to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the third temperature, that is, to control the third temperature to be between the minimum allowable operating oil temperature value and the maximum allowable operating oil temperature value, thereby simulating the wear state of the inter-axle differential during the actual driving of the vehicle. When it is determined that the test time for the operation of the drive assembly reaches the second preset time, it means that it can be tested whether the inter-axle differential is worn under the heavy-duty differential condition, and then the drive assembly is controlled to stop working.

[0048] Based on this, it is determined whether the inter-axle differential is worn according to the usage state parameters of the inter-axle differential under the heavy-duty differential condition. That is to say, the usage state parameters of the inter-axle differential under the starting shock condition are compared with the preset usage state parameters when the inter-axle differential is in a worn state. If the two are the same, it means that the test result of the inter-axle differential is worn. On the contrary, if the two are different, it means that the test result of the inter-axle differential is not worn. For example, the input torque of the intermediate axle is controlled to be the third input torque, the input speed of the intermediate axle is controlled to be the third input speed value, and the output speed of the intermediate axle is controlled to be the third output speed value. At this time, the usage state parameter of the inter-axle differential obtained is the third output torque of the intermediate axle. Whether the inter-axle differential is worn is judged by the third output torque of the intermediate axle. If the third output torque is the same as the preset torque when the inter-axle differential is in a worn state, it is determined that the inter-axle differential is worn; otherwise, it is determined that the inter-axle differential is not worn.

[0049] In some embodiments, controlling the working state of the wheels and / or the through shaft to be the simulated state under the corresponding test condition includes: controlling the working state of the wheels and the through shaft to be the second simulated state under the rear axle slip condition, and the second simulated state is the state where the wheels connected to the intermediate axle stop rotating, the wheels connected to the rear axle rotate, and the flange of the through shaft outputs.

[0050] Specifically, since the rear axle is in an idling state when it slips, the front axle is fixed so that the rear axle is in an idling state. Therefore, when conducting the wear test of the inter-axle differential under the condition of rear axle slip, the working states of the wheels and the through shaft are controlled to be in the first simulation state. Since the flange of the through shaft is in the output state, the power of the middle axle can be transmitted to the rear axle through the through shaft. Therefore, the wheels connected to the rear axle rotate, and at the same time, the wheels connected to the middle axle are controlled to stop rotating, thereby simulating the condition of rear axle slip and enabling the wear test of the inter-axle differential under the condition of rear axle slip.

[0051] In some embodiments, controlling the operation of the drive assembly according to test parameters includes: controlling the operation of the middle axle according to input parameters and output parameters, where the input parameters of the middle axle are the fourth input speed value and the fourth input torque, the output parameter of the middle axle is the fourth output speed value, the fourth output speed value is the operating speed of the through shaft, and the fourth output speed value = 2 × the fourth input speed value; controlling the cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the fourth temperature, where the minimum allowable operating oil temperature value ≤ the fourth temperature ≤ the maximum allowable operating oil temperature value; after determining that the test time for the operation of the drive assembly reaches the third preset time, controlling the drive assembly to stop operating, and the third preset time ≥ 150 s.

[0052] Among them, the fourth input speed value can be converted according to the instrument vehicle speed of 40 Km / h, and the fourth input torque can be set to 100 Nm.

[0053] Specifically, in order to simulate the condition of rear axle slip, the user sets the input speed of the middle axle to the fourth input speed value, the input torque to the fourth input torque, and the output speed to the fourth output speed value through the control panel of the bench test stand according to the operating conditions of the input parameters and output parameters of the middle axle under this condition, so as to be able to control the operation of the middle axle according to the fourth input speed value, the fourth input torque, and the fourth output speed value of the middle axle. At the same time, the oil temperature of the drive assembly during the actual driving of the vehicle needs to be within a certain range to ensure the lubrication performance, and the lubrication performance will affect the wear condition of the inter-axle differential. Then, the cooling device connected to the drive assembly is controlled to cool the oil temperature of the drive assembly so that the oil temperature during the operation of the drive assembly is the fourth temperature, that is, controlling the fourth temperature to be between the minimum allowable operating oil temperature value and the maximum allowable operating oil temperature value, thereby simulating the wear state of the inter-axle differential during the actual driving of the vehicle. When it is determined that the test time for the operation of the drive assembly reaches the third preset time, the third preset time is the minimum time required to test whether the inter-axle differential is worn under the condition of rear axle slip. That is to say, if the test time for the operation of the drive assembly reaches the third preset time, the wear test of the inter-axle differential can be completed, and then the drive assembly is controlled to stop operating.

[0054] Based on this, under the condition of rear axle slippage, the service condition parameters of the inter-axle differential are used to determine whether the inter-axle differential is worn. That is to say, under the condition of rear axle slippage, the service condition parameters of the inter-axle differential are compared with the preset service condition parameters when the inter-axle differential is in a worn state. If the two are consistent, it indicates that the test result of the inter-axle differential is worn. On the contrary, if the two are inconsistent, it indicates that the test result of the inter-axle differential is not worn. For example, when controlling the operation of the middle axle according to the fourth input rotational speed value, the fourth input torque, and the fourth output rotational speed value of the middle axle, the service condition parameter of the inter-axle differential obtained is the fourth output torque of the middle axle. Whether the inter-axle differential is worn is judged by the fourth output torque. If the fourth output torque is consistent with the preset torque when the inter-axle differential is in a worn state, it is determined that the inter-axle differential is worn; otherwise, it is confirmed that the inter-axle differential is not worn.

[0055] In addition, it should be noted that the fourth output torque can be measured by a torque sensor or calculated by the following calculation formula: Fourth output torque = Fourth input torque × Middle axle reduction ratio × Transmission efficiency / Middle and rear axle torque distribution coefficient Among them, the transmission efficiency is 0.97, and the middle and rear axle torque distribution coefficient can be 2. Setting the middle and rear axle torque distribution coefficient to 2 means that the middle and rear axle torques are equally divided.

[0056] In some embodiments, before controlling the working states of the wheels and / or the through shaft to the simulated states under the corresponding test conditions, it includes: controlling the wheels connected to the middle axle and the wheels connected to the rear axle to stop rotating, and controlling the through shaft flange to stop output; obtaining the running-in control parameters; and running in the drive assembly according to the running-in control parameters.

[0057] Specifically, running in the drive assembly is for the smooth progress of the subsequent wear test of the inter-axle differential. Controlling the wheels connected to the middle axle to stop rotating means controlling the input torque of the middle axle to be 0 Nm, controlling the output torque of the middle axle to be 0 Nm, and controlling the through shaft to stop output, then the wheels connected to the rear axle stop rotating. Then, the drive assembly is run in according to the above running-in control parameters, thereby ensuring the accuracy of the judgment of the wear state of the inter-axle differential.

[0058] In some embodiments, the running-in control parameters include the input rotational speed of the middle axle and the output rotational speed of the middle axle. Running in the drive assembly according to the running-in control parameters includes: controlling the middle axle to work with the fifth input rotational speed value and the fifth output rotational speed value; and determining that the oil temperature during the operation of the drive assembly reaches the minimum allowable working oil temperature value to complete the running-in of the drive assembly.

[0059] Exemplarily, the fifth input rotational speed value can be set to 500 rpm, and the fifth output rotational speed value can be measured by setting a torque sensor or calculated by the following calculation formula: Fifth output speed value = fifth input speed value / middle bridge reduction ratio Specifically, the user sets the fifth input speed value and the fifth output speed value of the middle bridge through the control panel of the bench test bench. Among them, the fifth input speed value is 500rmp, and the input torque is set to 0Nm to reduce the load. During the running-in process, the oil temperature is controlled to rise from room temperature to the minimum allowable working oil temperature value, i.e., 60°C. When the oil temperature reaches 60°C, the running-in of the drive assembly is stopped, and the running-in of the drive assembly is completed. The output torque is 0NM.

[0060] Based on the above, the test includes conditions such as mid-axle slippage, rear-axle slippage, starting impact, and heavy-load differential conditions. The test equipment is used to determine whether there is an unexplained increase of 10% in the input torque under the test conditions during the slippage phase. Specifically, it is determined whether the change in the difference between the input speed and the output speed is greater than 10% of the preset speed difference. If so, the test should be stopped and inspected. The inter-axle differential fails during the wear phase or stops after 35 hours, where 35 hours is set by referring to industry standards. Among them, the mid-axle installation angle can be set according to the unloaded state of the vehicle, or set according to a fixed angle, for example, it can be set to 3.5 degrees. In addition, the test parameters can float by 20%, which can be understood as reasonable within 20% of the test parameters.

[0061] In some embodiments, the inter-axle differential includes a cross shaft, planetary gears, a planetary gear gasket and an inter-axle differential housing, and the test result of the inter-axle differential is determined according to the usage status parameters, including: if the usage status parameters meet the preset wear conditions, then the test result of the inter-axle differential is determined to be wear; wherein the preset wear conditions include at least any one of the following: the output torque of the middle bridge is higher than the preset torque threshold; the cross shaft and the planetary gears cannot rotate relative to each other; there is sintering in the inter-axle differential; the wear marks of the cross shaft and the planetary gears are higher than 1 / 2× the mating length; the maximum wear mark depth of the cross shaft and the planetary gears is higher than the preset wear mark depth; the wear amount of the planetary gear gasket is higher than the first preset wear amount; the wear amount of the inter-axle differential housing is higher than the second preset wear amount.

[0062] Among them, according to market claim experience, the preset wear mark depth can be set to 0.1mm, and the second preset wear amount can be set to 0.3mm. The matching length between the cross shaft and the planetary gear is the contact length between the cross shaft and the planetary gear. The design of this matching length takes into account the friction and wear that may occur when the gear rotates, as well as the flow and distribution of the lubricating oil.

[0063] Specifically, since the higher the output torque of the intermediate axle, the greater the wear degree of the interaxle differential, when it is determined that the output torque of the intermediate axle is higher than the preset torque threshold calibrated according to the wear of the interaxle differential, it is determined that the interaxle differential is worn; if it is detected that the cross shaft and the planetary gear cannot rotate relative to each other, it is determined that the interaxle differential is worn; if it is detected that there is a sintering phenomenon in the interaxle differential; if it is detected that the wear marks of the cross shaft and the planetary gear are higher than 1 / 2×the mating length, it is determined that the interaxle differential is worn; if it is detected that the maximum wear mark depth of the cross shaft and the planetary gear is higher than the preset wear mark depth, where the preset wear mark depth can be understood as the upper limit value of the preset wear mark depth of the cross shaft and the planetary gear for a safe or acceptable wear degree, it is determined that the interaxle differential is worn; if it is detected that the wear amount of the planetary gear shim is higher than the first preset wear amount, it is determined that the interaxle differential is worn; if it is detected that the wear amount of the interaxle differential housing is higher than the second preset wear amount, it is determined that the interaxle differential is worn. Thus, the wear detection of the interaxle differential is realized.

[0064] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0065] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirits of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for testing an inter-axle differential, characterized in that: For a drive assembly, the drive assembly includes an inter-axle differential, a middle bridge and a rear bridge, the inter-axle differential is arranged in the middle bridge, and the middle bridge is connected to the rear bridge through a through shaft, and the test method includes: Obtaining test parameters corresponding to different test conditions, wherein the test parameters include at least one or more of an input parameter of a middle axle, an output parameter of a middle axle, oil temperature, test time, and test times, and the test conditions include at least one or more of a middle axle slip condition, a rear axle slip condition, a start impact condition, and a heavy-load differential condition; Controlling the working state of the wheel and / or the through shaft to be a simulated state under the corresponding test condition; Controlling the operation of the drive assembly according to the test parameters to obtain the use status parameters of the inter-axle differential under different test conditions; A test result of the inter-axle differential is determined according to the usage status parameter.

2. The test method of the inter-axle differential according to claim 1, characterized in that: Controlling the working state of the wheel and / or the through shaft to be a simulated state under the corresponding test condition includes: The working state of the control wheels and the through-axle is a first simulation state under a middle bridge slip condition, a starting impact condition or a heavy-load differential condition, wherein the first simulation state is a state in which the wheels connected to the middle bridge are running, the wheels connected to the rear axle are stopped, and the through-axle flange stops outputting.

3. The test method of the inter-axle differential according to claim 2, characterized in that: When the test condition is a mid-bridge slip condition, controlling the drive assembly to work according to the test parameters includes: The operation of the middle axle is controlled according to the input parameter and the output parameter, wherein the input parameter of the middle axle is a first input speed value and a first input torque, the output parameter of the middle axle is a first output speed value, the first output speed value is the running speed of the wheels connected to the middle axle, and the first output speed value=2×first input speed value / middle axle reduction ratio; Controlling a cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature of the drive assembly when working is a first temperature, wherein a minimum allowable working oil temperature value ≤ the first temperature ≤ a maximum allowable working oil temperature value; After determining that the test time of the driving assembly reaches a first preset time, the driving assembly is controlled to stop working, and the first preset time is ≥300s.

4. The test method of the inter-axle differential according to claim 2, characterized in that: The input parameters include input torque and input speed. When the test condition is a starting impact condition, controlling the drive assembly to work according to the test parameters includes: Controlling the input torque of the middle bridge to be a second input torque, and controlling the input speed of the middle bridge to be gradually loaded from static to a second input speed value, wherein the second input torque=rated input torque of the middle bridge×a, where a is less than 1; Controlling a cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature of the drive assembly when working is a second temperature, wherein a minimum allowable working oil temperature value ≤ the second temperature ≤ a maximum allowable working oil temperature value; After determining that the number of tests on the drive assembly reaches a preset number, the drive assembly is controlled to stop working.

5. The test method of the inter-axle differential according to claim 2, characterized in that: When the test condition is a heavy-load differential condition, controlling the drive assembly to work according to the test parameters includes: Controlling the operation of the middle bridge according to the input parameter and the output parameter, wherein the input parameter of the middle bridge is a third input speed value and a third input torque, the output parameter of the middle bridge is a third output speed value, and the third output speed value is the running speed of the wheels connected to the middle bridge; Controlling a cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature of the drive assembly when working is a third temperature, wherein a minimum allowable working oil temperature value ≤ the third temperature ≤ a maximum allowable working oil temperature value; After determining that the test time of the driving assembly reaches a second preset time, the driving assembly is controlled to stop working, wherein the second preset time is ≥35h.

6. The test method of the inter-axle differential according to claim 1, characterized in that: Controlling the working state of the wheel and / or the through shaft to be a simulated state under a corresponding test condition includes: The working state of the wheels and the through shaft is controlled to be a second simulation state under the rear axle slip condition, wherein the second simulation state is a state in which the wheels connected to the middle axle stop running, the wheels connected to the rear axle run, and the through shaft flange outputs.

7. The test method of the inter-axle differential according to claim 6, characterized in that: Controlling the operation of the drive assembly according to the test parameters includes: Controlling the operation of the middle bridge according to the input parameter and the output parameter, wherein the input parameters of the middle bridge are a fourth input speed value and a fourth input torque, the output parameter of the middle bridge is a fourth output speed value, the fourth output speed value is the running speed of the through shaft, and the fourth output speed value=2×the fourth input speed value; Controlling a cooling device connected to the drive assembly to cool the oil temperature of the drive assembly so that the oil temperature of the drive assembly when working is a fourth temperature, wherein a minimum allowable working oil temperature value ≤ the fourth temperature ≤ a maximum allowable working oil temperature value; After determining that the test time of the driving assembly reaches a second preset time, the driving assembly is controlled to stop working, and the second preset time is ≥150s.

8. The method for testing the inter-axle differential according to claim 1, characterized in that: Before controlling the working state of the wheel and / or the through shaft to be a simulated state under the corresponding test condition, the method includes: Controlling the wheels connected to the middle axle and the wheels connected to the rear axle to stop running, and controlling the flange of the through shaft to stop output; Get the running-in control parameters; The drive assembly is run-in according to the run-in control parameters.

9. The test method of the inter-axle differential according to claim 8, characterized in that: The running-in control parameters include the input speed of the middle bridge and the output speed of the middle bridge, and the drive assembly is run-in according to the running-in control parameters, including: Controlling the operation of the intermediate bridge at a fifth input speed value and a fifth output speed value; It is determined that the oil temperature of the drive assembly reaches the minimum allowable working oil temperature value when the drive assembly is working, and the running-in of the drive assembly is completed.

10. The method for testing an inter-axle differential according to any one of claims 1 to 9, wherein the inter-axle differential comprises a cross shaft, a planetary gear, a planetary gear washer and an inter-axle differential housing, and determining the test result of the inter-axle differential according to the use status parameter comprises: If the use status parameter satisfies a preset wear condition, determining that the test result of the inter-axle differential is wear; The preset wear condition includes at least one of the following: The output torque of the intermediate bridge is higher than a preset torque threshold; The cross shaft and the planetary gear cannot rotate relative to each other; The inter-axle differential has sintering phenomenon; The wear marks of the cross shaft and the planetary gear are higher than 1 / 2× the matching length; The maximum wear scar depth between the cross shaft and the planetary gear is higher than the preset wear scar depth; The wear amount of the planetary gear gasket is higher than a first preset wear amount; The wear amount of the inter-axle differential case is higher than a second preset wear amount.

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