Reliability test method and device for integrated electric drive axle motor system

Abstract

The invention discloses an integrated electric drive axle motor system reliability test method and device, and the method comprises the steps: collecting the hundred kilometer load spectrum data of a plurality of vehicles, carrying out the data processing of the data, obtaining the effective vehicle operation speed and torque, and recognizing the efficient working interval of a motor according to the efficiency MAP of the motor; a gear shifting speed point of an axle is obtained according to the effective vehicle running speed, the speed ratio of the speed reducer and the efficient working interval of the motor, gear identification is carried out through the matching relation between the speed ratio of the speed reducer and the vehicle speed, and the input conditions of motor system reliability test torque and rotating speed are formed; designing an initial working condition test table of a motor system reliability test, performing adjustment according to actual working conditions of the subdivided market to obtain a final demand working condition test table, and performing a motor fatigue cycle test according to the final demand working condition test table and a product design mileage demand; a double-motor electric drive bridge structure is adopted to replace an original test bed, and the actual state of the motor in the electric drive bridge is better fed back.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive axle motor testing, and in particular to a reliability testing method and a device for an integrated electric drive axle motor system. Background Art

[0002] In the field of new energy commercial vehicles, due to the advantages of high integration, high efficiency and low energy consumption of electric drive axles, their application scope and market share are constantly increasing. However, with high integration comes the continuous improvement of the requirements for motor reliability. Therefore, in the development stage of integrated electric drive axles, it is necessary to conduct comprehensive reliability tests on the motor system. Although the existing motor reliability tests basically meet the basic needs of its reliability test, there are mainly the following problems: First, the motor reliability test system does not fully consider the influence of multiple factors such as temperature, vibration, torque transmission, circuit, etc. faced by the motor after integration into the electric drive axle, resulting in a large difference between the reliability test results and the product matching application results, affecting the accuracy and efficiency of product development; second, the motor test conditions are designed based on the national standard principles, and the driving differences of vehicles in different market segments are not fully considered. The difference between the motor reliability test results and the actual performance of the product is large, which affects the market compliance of motor development and makes it difficult for the product to meet market demand; third, the conventional motor reliability test system has a single function and fails to consider the reliability test requirements of the motor system of the integrated electric drive axle in different configurations such as single gear or double gear. Therefore, a large number of repetitive tests are required to verify the reliability of the electric drive axle motor system, which has high test costs and long product development cycles. Summary of the invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a reliability test method and device for an integrated electric drive bridge motor system. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0004] A reliability test method for an integrated electric drive axle motor system, the motor system comprising a front drive motor and a rear drive motor, the test method comprising:

[0005] Step 1: Randomly collect 100 km load spectrum data of several electric vehicles of the same type;

[0006] Step 2: Processing the load spectrum data of the vehicle per 100 kilometers to obtain the effective vehicle running speed and torque, and identifying the efficient working range of the motor according to the efficiency MAP diagram of the motor;

[0007] Step 3: Obtain the shift speed point of the axle according to the effective vehicle running speed, the speed ratio of the reducer and the efficient working range of the motor, and then perform gear identification through the matching relationship between the speed ratio of the reducer and the vehicle speed to form the input conditions of torque and speed for the motor system reliability test;

[0008] Step 4: Based on the characteristics of vehicle driving conditions, design the initial operating condition test table for the motor system reliability test, then adjust the operating time of each operating condition according to the actual operating conditions of the market segment, and obtain the final required operating condition test table for the motor system reliability test, and conduct motor fatigue cycle test based on the final required operating condition test table and product design mileage requirements.

[0009] Furthermore, step 4 includes the following steps:

[0010] Step 4.1: Discretize the effective vehicle running speed and torque to form different operating point data;

[0011] Step 4.2: Then, according to the operating point data and the gear shift speed point, the motor speed, torque, frequency of occurrence of the same gear and the gear duration ratio of several electric drive vehicles at different gears are counted;

[0012] Step 4.3: Convert the frequency domain signals of the motor speed and torque into continuous time domain signals according to the gear occurrence frequency and the gear duration ratio;

[0013] Step 4.4: Draw an initial working condition test table of the motor reliability test according to the time domain signal;

[0014] Step 4.5: Revise the initial working condition test table according to the actual working conditions of the market segment to obtain the final required working condition test table for the motor system reliability test that meets the characteristics of the market segment;

[0015] Step 4.6: Take the weighted sum of the vehicle speed and duration corresponding to all operating points to obtain the corresponding vehicle running mileage under each cycle, and then obtain the target number of cycles for the motor system reliability test based on the product design mileage;

[0016] Step 4.7: Finally, the motor fatigue cycle test is performed according to the final required working condition test table and the target number of cycles.

[0017] Furthermore, the initial operating condition test table includes: the integrated electric drive axle shifting one gear from neutral, speeding up in first gear, constant speed in first gear, decelerating in first gear, shifting from first gear to second gear and pausing, speeding up in second gear, constant speed in second gear, decelerating in second gear, shifting from second gear to one gear, and shifting from first gear to neutral as well as the motor torque, speed and duration under each operating condition.

[0018] Furthermore, in step 4.7, when the motor fatigue cycle test is performed, the load is applied to the tested motor by using the front drive motor and the rear drive motor of the integrated electric drive axle towing each other.

[0019] Another embodiment of the present invention discloses an integrated electric drive bridge motor system reliability test device, which is used to implement the above test method, and specifically includes a modular integrated electric drive bridge body, a first motor controller MCU, a second motor controller MCU, a reduction gearbox controller TCU and a comprehensive test controller; wherein,

[0020] The modular integrated electric drive axle body includes a front drive motor and a rear drive motor; the reduction gearbox controller TCU is integrated in the modular integrated electric drive axle body, and the single / double-speed reduction gearbox connected to the front drive motor and the single / double-speed reduction gearbox connected to the rear drive motor can be controlled to shift and fix the duration of each gear through the TCU; the first motor controller MCU is electrically connected to the comprehensive test controller and the front drive motor respectively, and the front drive motor can be controlled to have a speed and torque loading adjusted under the control of the comprehensive test controller through the first motor controller MCU; the second motor controller MCU is connected to the comprehensive test controller and the rear drive motor respectively, and the rear drive motor can be controlled to have a speed and torque loading adjusted under the control of the comprehensive test controller through the second motor controller MCU.

[0021] Beneficial effects of the present invention:

[0022] 1. Based on the vehicle running road load spectrum data, the present invention forms the input conditions of torque and speed for motor reliability test through data cleaning and gear identification. At the same time, combined with the characteristics of vehicle driving conditions, the motor reliability condition test table is designed. According to the test table and the product design mileage requirements, the motor fatigue cycle test is carried out, the number of cycles is counted, and the motor system reliability test is completed, thereby effectively ensuring the fit between the motor reliability test results and the actual market application;

[0023] 2. The present invention does not need to set up an additional load application power source, and directly adopts a dual-motor electric drive bridge structure to replace the original test bench, that is, the load is applied by using a dual motor towing method in front and behind the axle, which can better feedback the actual state of the motor in the electric drive bridge, avoiding the problem of large differences between the motor test results and the actual application results;

[0024] 3. The test device has a simple structure and low cost. At the same time, the motor test conditions are closer to the actual conditions and have higher accuracy. It can also conduct test verification of the front and rear motors at the same time, which has higher test efficiency.

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the process of the present invention;

[0027] Figure 2A flow chart of the design method for the final required working condition test table;

[0028] Figure 3 It is the conversion diagram between vehicle speed and motor speed;

[0029] Figure 4 It is the conversion diagram between vehicle wheel end torque and motor output torque;

[0030] Figure 5 Schematic diagram of a single loading cycle for reliability test of integrated electric drive axle motor system;

[0031] Figure 6 A schematic diagram of a reliability test device for an integrated electric drive axle motor system;

[0032] Figure 7 Another schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0034] Example 1

[0035] See also Figure 1~Figure 5 The embodiment of the present invention provides a reliability test method for an integrated electric drive bridge motor system, which specifically includes the following steps:

[0036] Step 1: Randomly collect 100-kilometer load spectrum data of 50 to 100 electric vehicles of the same type.

[0037] Step 2: Process the load spectrum data of the vehicle per 100 kilometers to obtain the effective vehicle running speed and torque, and identify the efficient working range of the motor according to the efficiency MAP diagram of the motor.

[0038] The load spectrum data of the vehicle per 100 kilometers is cleaned to filter out useless data, and the data is enhanced by a rain flow counting method to obtain an effective vehicle running speed signal, including speed and torque.

[0039] Step 3: Obtain the shift speed point of the axle according to the effective vehicle operating speed, the speed ratio of the reducer and the efficient working range of the motor, and then perform gear identification through the matching relationship between the speed ratio of the reducer and the vehicle speed to form the input conditions of the torque and speed of the motor system reliability test.

[0040] Set the motor's high-efficiency operating range speed to N1~N2, the vehicle's running speed to V, and the speed ratio of the electric drive axle reducer to i. In order to keep the motor in the high-efficiency operating range, the electric drive axle reducer assembly needs to meet the following conditions:

[0041]

[0042] Where, d is the tire diameter;

[0043] As the vehicle speed increases or decreases, the motor speed will also increase or decrease. When the value exceeds the efficient working range of the motor, a gear shift operation is required. The speed value corresponding to the gear shift is the gear shift speed point of the axle. Then, the speed ratio of the reducer corresponding to the gear shift speed point is calculated according to the above formula, and the gear position is identified through the gear shift speed point and the speed ratio of the reducer.

[0044] The test variables of the motor system reliability test are the motor speed and torque, and the factor affecting the motor torque and speed is the gear position of the reducer. Therefore, the change of gear position is the input condition for adjusting the test variables of the motor reliability test.

[0045] Step 4: Based on the driving condition characteristics of the same type of vehicles, design the initial operating condition test table for the motor system reliability test, as shown in Table 1. The initial operating condition test tables for different motors are different. Then, adjust the operating time of each operating condition according to the actual operating conditions of the market segment to obtain the final required operating condition test table for the motor system reliability test, and conduct motor fatigue cycle tests based on the final required operating condition test table and the product design mileage requirements.

[0046] Table 1 Initial working condition test table

[0047]

[0048] like Figure 2 As shown, step 4 specifically includes the following steps:

[0049] Step 4.1: Discretize the effective vehicle running speed and torque to form different operating point data, which includes the gear position of the transmission, the motor speed and the motor torque corresponding to the gear position.

[0050] Step 4.2: Then, according to the operating point data, the motor speed, torque, frequency of occurrence of the same gear and the gear duration ratio of the same type of motor in different gears of 50 to 100 electric drive vehicles are counted;

[0051] The motor speed is converted from the vehicle speed, as shown in the following example: Figure 3 As shown; the torque of the motor is converted from the vehicle wheel end torque, as shown in Figure 4 shown.

[0052] Step 4.3: Convert the frequency domain signals of the motor speed and torque into continuous time domain signals according to the gear occurrence frequency and the gear duration ratio;

[0053] Step 4.4: Draw the initial working condition test table of the motor system reliability test based on the continuous time domain signal;

[0054] The initial operating condition test table includes: the integrated electric drive axle shifting one gear in neutral, speeding up in one gear, constant speed in first gear, decelerating in first gear, shifting from first gear to second gear and pausing, speeding up in second gear, constant speed in second gear, decelerating in second gear, shifting from second gear to one gear, and shifting from first gear to neutral as well as the motor torque, speed and duration under each operating condition.

[0055] Step 4.5: Revise the initial operating condition test table according to the actual operating conditions of the market segment to obtain the final required operating condition test table for the motor system reliability test that meets the characteristics of the market segment.

[0056] Step 4.6: Take a weighted sum of the vehicle speed and duration corresponding to the operating point to obtain the corresponding vehicle running mileage in each cycle, and then obtain the target number of cycles for the motor system reliability test based on the design mileage of the product;

[0057] Step 4.7: Perform motor fatigue cycle test according to the final required working condition test table and target cycle number.

[0058] Specifically, the integrated electric drive axle motor system includes a front drive motor and a rear drive motor. When conducting a motor fatigue cycle test, the front drive motor and the rear drive motor of the axle are used to tow each other (that is, one motor rotates forward and the other motor rotates reversely) to apply a load to the tested drive motor. That is, when testing the reliability of the front drive motor, the rear drive motor is used to apply a load to the front drive motor; when testing the reliability of the rear drive motor, the front drive motor is used to apply a load to the rear drive motor; and when both the front drive motor and the rear drive motor need to undergo reliability tests, when the two motors are tested separately according to the operating condition test table, a load is applied to the other motor at the same time.

[0059] Example 2

[0060] See also Figure 6 The embodiment of the present invention discloses an integrated electric drive bridge motor system reliability test device, which is used to test the integrated electric drive bridge motor system reliability test method described in Example 1, and specifically includes: a modular integrated electric drive bridge body, a first motor controller MCU, a second motor controller MCU, a reduction gearbox controller TCU and a comprehensive test controller; wherein,

[0061] The modular integrated electric drive axle body includes a front drive motor and a rear drive motor;

[0062] The reduction gearbox controller TCU is integrated in the modular integrated electric drive bridge body, and the single / double-speed reduction gearbox can control the gear shift and fix the duration of each gear through the reduction gearbox controller TCU; the first motor controller MCU is electrically connected to the comprehensive test controller and the front drive motor respectively, and the front drive motor can adjust the speed and torque loading of the front drive motor through the first motor controller MCU under the control of the comprehensive test controller; the second motor controller MCU is connected to the comprehensive test controller and the rear drive motor respectively, and the rear drive motor can adjust the speed and torque loading of the rear drive motor through the second motor controller MCU under the control of the comprehensive test controller. In addition, the first motor controller MCU and the second motor controller MCU can also record and monitor parameters such as temperature, current, voltage, etc. during the test in real time, record the number of cycle tests, automatically pause or terminate the test, etc.

[0063] The gear position of the reduction gearbox is adjusted through the integrated reduction gearbox controller TCU, and the reduction gearbox on the fixed reverse loading motor side is always in single-gear or two-gear transmission, thereby realizing the reliability test of the dual-motor system under two integrated electric drive axle modes: front two gears + rear one gear (the reduction gearbox matched with the front drive motor is a two-gear reduction gearbox, and the reduction gearbox matched with the rear drive motor is a single-gear reduction gearbox) and front two gears + rear two gears (the reduction gearbox matched with the front drive motor is a two-gear reduction gearbox, and the reduction gearbox matched with the rear drive motor is a two-gear reduction gearbox).

[0064] Based on the final required operating condition test table of the motor reliability test, the first motor controller MCU and the second motor controller MCU are controlled by the integrated test controller. The first motor controller MCU and the second motor controller MCU load the front drive motor and the rear drive motor. At the same time, the reduction gear controller TCU performs gear shifting and fixes the duration of each gear. Then, the cycle test is performed according to the operating condition test table. At the same time, the integrated test controller records and monitors the temperature, current, voltage and other parameters in real time during the test, and records the number of cycle tests. When relevant values, such as temperature, exceed the predetermined range, the test can be automatically paused. When the relevant values ​​return to a reasonable range, the cycle test is automatically started until the cycle test is completed.

[0065] The present invention constructs a test system by building a modular integrated electric drive axle body, fully considering the influence of multiple factors such as temperature, vibration, torque transmission, circuit, etc. faced by the motor after being integrated into the electric drive axle, reducing the difference between the test results and the product matching application results, and improving the development accuracy and verification efficiency of motor products;

[0066] The present invention fully considers the motor system reliability test requirements of the single and double motors of the integrated electric drive axle in different configurations such as single gear or double gear, and meets the test demands under various configurations by constructing a modular test device and quickly replacing the reduction box module in the test system module, thereby effectively avoiding the problems of high test cost and long product development cycle caused by the single function of the existing conventional motor reliability test system and the need for multiple repetitive tests for motor verification.

[0067] Example 3

[0068] See also Figure 7 The embodiment of the present invention provides a reliability test method for an integrated electric drive bridge motor system, which specifically includes the following steps:

[0069] Step 1: Collect the operating load spectra of several electric vehicles of the same type;

[0070] Step 2: Process the vehicle speed and output torque data (remove impurities and enhance them), and identify the efficient working range of the motor;

[0071] Step 3: Calculate the shift speed point, convert the drive motor speed / torque information based on the different gear ratios of the reducer, and finally form the motor system reliability initial working condition test table;

[0072] Step 4: Then, based on the actual working conditions of the market segment, adjust the operating time of each working point to obtain the final reliability verification working condition test table;

[0073] Step 5: According to the reliability verification working condition test table, the comprehensive test controller controls the first motor controller MCU and the second motor controller MCU, and the integrated reduction gearbox controller TCU to shift gears and fix the duration of each gear;

[0074] Step 6: Based on the product design mileage requirements, determine the number of cycle tests and perform statistics on the number of motor system operating cycles;

[0075] Step 7: Then complete the motor system reliability test according to the operating condition test table and number of cycles.

[0076] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A reliability test method for an integrated electric drive axle motor system, characterized in that: The motor system includes a front drive motor and a rear drive motor, and the test method includes: Step 1: Randomly collect 100 km load spectrum data of several electric vehicles of the same type; Step 2: Processing the load spectrum data of the vehicle per 100 kilometers to obtain the effective vehicle running speed and torque, and identifying the efficient working range of the motor according to the efficiency MAP diagram of the motor; Step 3: Obtain the shift speed point of the axle according to the effective vehicle running speed, the speed ratio of the reducer and the efficient working range of the motor, and then perform gear identification through the matching relationship between the speed ratio of the reducer and the vehicle speed to form the input conditions of torque and speed for the motor system reliability test; Step 4: Based on the characteristics of vehicle driving conditions, design the initial operating condition test table for the motor system reliability test, then adjust the operating time of each operating condition according to the actual operating conditions of the market segment, and obtain the final required operating condition test table for the motor system reliability test, and conduct motor fatigue cycle test based on the final required operating condition test table and product design mileage requirements.

2. The reliability test method of the integrated electric drive bridge motor system according to claim 1, characterized in that: The step 4 comprises the following steps: Step 4.1: Discretize the effective vehicle running speed and torque to form different operating point data; Step 4.2: Then, according to the operating point data and the gear shift speed point, the motor speed, torque, frequency of occurrence of the same gear and the gear duration ratio of several electric drive vehicles at different gears are counted; Step 4.3: Convert the frequency domain signals of the motor speed and torque into continuous time domain signals according to the gear occurrence frequency and the gear duration ratio; Step 4.4: Draw an initial working condition test table of the motor reliability test according to the time domain signal; Step 4.5: Revise the initial working condition test table according to the actual working conditions of the market segment to obtain the final required working condition test table for the motor system reliability test that meets the characteristics of the market segment; Step 4.6: Take the weighted sum of the vehicle speed and duration corresponding to all operating points to obtain the corresponding vehicle running mileage under each cycle, and then obtain the target number of cycles for the motor system reliability test based on the product design mileage; Step 4.7: Finally, the motor fatigue cycle test is performed according to the final required working condition test table and the target number of cycles.

3. The reliability test method of the integrated electric drive bridge motor system according to claim 2, characterized in that: The initial operating condition test table includes: the integrated electric drive axle shifting one gear in neutral, speeding up in one gear, constant speed in first gear, decelerating in first gear, shifting from first gear to second gear and pausing, speeding up in second gear, constant speed in second gear, decelerating in second gear, shifting from second gear to one gear, and shifting from first gear to neutral as well as the motor torque, speed and duration under each operating condition.

4. The reliability test method of the integrated electric drive bridge motor system according to claim 2, characterized in that: In step 4.7, when the motor fatigue cycle test is performed, the load is applied to the tested motor by using the front drive motor and the rear drive motor of the integrated electric drive axle towing each other.

5. An integrated electric drive axle motor system reliability test device, used to test the integrated electric drive axle motor system reliability test method according to any one of claims 1 to 4, characterized in that: It includes a modular integrated electric drive bridge body, a first motor controller MCU, a second motor controller MCU, a reduction gearbox controller TCU and a comprehensive test controller; among which, The modular integrated electric drive axle body includes a front drive motor and a rear drive motor; the reduction gearbox controller TCU is integrated in the modular integrated electric drive axle body, and the single / double-speed reduction gearbox connected to the front drive motor and the single / double-speed reduction gearbox connected to the rear drive motor can be controlled to shift and fix the duration of each gear through the TCU; the first motor controller MCU is electrically connected to the comprehensive test controller and the front drive motor respectively, and the front drive motor can be controlled to have a speed and torque loading adjusted under the control of the comprehensive test controller through the first motor controller MCU; the second motor controller MCU is connected to the comprehensive test controller and the rear drive motor respectively, and the rear drive motor can be controlled to have a speed and torque loading adjusted under the control of the comprehensive test controller through the second motor controller MCU.

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