A testing device for an electric drive system and an electric drive system

Abstract

This disclosure provides a testing device for an electric drive system and the electric drive system itself. The electric drive system includes a motor and a reducer connected to each other. The testing device includes a temperature sensor, a rotor spindle, a reducer input shaft, an annular rotor transmitter, an annular stator receiver, and a speed sensor. The temperature sensor is uniformly arranged axially in the gaps between the magnets in the rotor of the motor and is used to detect the temperature of the magnets. Torque strain gauges are disposed on the surfaces of the rotor spindle and the reducer input shaft. The temperature sensor and the torque strain gauges are connected to the annular rotor transmitter via test wires. The annular stator receiver is disposed opposite to the annular rotor transmitter. This disclosure can solve vehicle-wide problems such as motor thermal performance issues and abnormal noise or failure of reducer power coupling, fundamentally solving the performance and durability problems of electric drive systems, saving high development costs and significantly shortening the verification cycle.

Description

Technical Field

[0001] This disclosure relates to the field of vehicle testing technology, and more specifically to a testing device for an electric drive system and an electric drive system. Background Technology

[0002] As is well known, the electric drive system of current mainstream pure electric passenger vehicles mainly includes assemblies such as controllers, inverters, motors, and reducers. For separate motors and reducers, the motor output shaft and the reducer input shaft are usually connected by a splice. The temperature of the motor rotor magnets can only be calculated through simulation due to high-speed rotation. The speed and torque of the motor output shaft are also estimated through motor resolvers and models. The speed and torque of the reducer input shaft 3 can only depend on the speed and torque of the motor output shaft. Under rapid acceleration and deceleration, as well as on poor road conditions, the motor rotor temperature will become abnormal, and abnormal wear and vibration will also occur at the splice between the motor and reducer, which will greatly affect the reliability and comfort of the entire vehicle. The electric drive system's motor and reducer transmit torque via splines. These splines have a clearance fit, and under acceleration, deceleration, or harsh operating conditions, abnormal wear can occur on the splines, leading to abnormal noises, spline breakage, and even extreme and dangerous situations such as loss of vehicle power. At the same time, especially under the aforementioned harsh operating conditions, the temperature of the motor rotor's magnets will also change in real time. In the past, thermal model simulation calculations were not based on actual measurements and calibration under typical vehicle operating conditions, which would lead to a significant decrease in the thermal performance of the electric drive system, severely affecting the vehicle's power performance, and even causing power failures such as high-temperature demagnetization of the electric drive system.

[0003] In existing technologies, the temperature of the electronic rotor magnets is usually calculated and simulated based on the motor's thermal model, and then combined with bench tests for performance and durability testing, which is costly and time-consuming. For problems such as abnormal noise and short shaft failure caused by spline wear in the connection between the motor and the reducer, spline strength analysis and improvement are usually carried out. However, it is impossible to accurately simulate the actual vehicle conditions based on the bench test. Only after improvement can the whole vehicle durability test be carried out, which is inefficient, cannot directly pinpoint the root cause, and will also lead to repeated modifications and verifications, wasting a lot of time and resources. Summary of the Invention

[0004] The purpose of this disclosure is to provide a testing device and an electric drive system for electric drive systems, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the embodiments of this disclosure adopt the following technical solutions:

[0006] A testing apparatus for an electric drive system, the electric drive system including a motor and a reducer connected to each other, the testing apparatus including a temperature sensor, a rotor spindle, a reducer input shaft, an annular rotor transmitter, an annular stator receiver, and a speed sensor, the temperature sensor being uniformly arranged axially in the gaps between the magnets in the rotor of the motor, and used to detect the temperature of the magnets, torque strain gauges being disposed on the surfaces of the rotor spindle and the reducer input shaft, the temperature sensor and the torque strain gauges being connected to the annular rotor transmitter via test wires, and the annular stator receiver being disposed opposite to the annular rotor transmitter.

[0007] In some embodiments, the testing apparatus further includes a data acquisition unit, wherein the temperature sensor, the annular rotor transmitter, the annular stator receiver, and the speed sensor are all connected to the data acquisition unit.

[0008] In some embodiments, the testing apparatus further includes a CAN communication device, through which the data acquisition instrument communicates with the vehicle's controller.

[0009] In some embodiments, a first spline is provided at the end of the rotor spindle and a second spline is provided at the end of the input shaft of the reducer, the second spline being connected to the first spline.

[0010] In some embodiments, the wires corresponding to the temperature sensor are arranged along radial and axial wire holes provided on the rotor spindle.

[0011] In some embodiments, the annular rotor transmitter is based on a flexible transmitter circuit board, which is fixed to the rotor spindle by an annular tooling.

[0012] In some embodiments, the annular stator receiver is fixed inside the housing of the motor and the housing of the reducer by a sensor bracket.

[0013] In some embodiments, the annular stator receiver is coaxially arranged with the annular rotor transmitter.

[0014] In some embodiments, the speed sensor is mounted on the sensor bracket and is used to test the speeds of the rotor spindle and the reducer input shaft, respectively.

[0015] This disclosure also provides an electric drive system that includes the testing apparatus described in any of the above technical solutions.

[0016] This disclosure enables real-time and accurate testing and calibration of the rotor temperature, torque, and speed of the electric drive system under typical road conditions. It solves vehicle-wide problems such as motor thermal performance issues and abnormal noise or failure of the reducer's power coupling, fundamentally addressing the performance and durability issues of the electric drive system, saving significant development costs and greatly shortening the verification cycle. This disclosure also enables precise testing and processing of the actual coupling state of the motor and reducer at high speeds, overcoming the limitations of previous inaccurate bench tests of reducer output torque and speed, and CAE simulations that could not accurately simulate the real-world conditions of a vehicle. This improves the comfort and reliability of the electric drive system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a test apparatus for an electric drive system in an embodiment of this disclosure;

[0019] Figure 2 This is a schematic diagram of the connection between the motor and the reducer in an embodiment of this disclosure.

[0020] Figure label:

[0021] 1-Temperature sensor; 2-Rotor spindle; 3-Reducer input shaft; 4-Annular rotor transmitter; 5-Annular stator receiver; 6-Speed ​​sensor; 7-Data acquisition instrument; 8-Sensor bracket; 9-Test lead wire; 10-Motor; 11-Motor housing; 12-Magnet; 13-Motor stator; 20-Reducer; 21-First spline; 22-Torque strain gauge; 23-Reducer housing; 31-Second spline; 32-Torque strain gauge; 41-Differential assembly; 42-First-stage reduction gear pair; 43-Second-stage reduction gear pair. Detailed Implementation

[0022] Various embodiments and features of this disclosure are described herein with reference to the accompanying drawings.

[0023] It should be understood that various modifications can be made to the embodiments described herein. Therefore, the above description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope and spirit of this disclosure will be apparent to those skilled in the art.

[0024] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present disclosure and, together with the general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure.

[0025] These and other features of this disclosure will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0026] It should also be understood that although this disclosure has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of this disclosure, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0027] The above and other aspects, features and advantages of this disclosure will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0028] Specific embodiments of this disclosure are described thereafter with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this disclosure, which may be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure this disclosure. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely to serve as the basis and representative basis for the claims to teach those skilled in the art to use this disclosure in a variety of substantially any suitable detailed structures.

[0029] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in still another embodiment,” all of which may refer to one or more of the same or different embodiments according to this disclosure.

[0030] This disclosure relates to a testing device for an electric drive system, which mainly includes a motor and a reducer. Compared with the traditional internal combustion engine and transmission, it has the characteristic of rapid torque response of the motor. Although a torque converter or torsional damper can be installed between the motor and the reducer to buffer the instantaneous torque change of the motor, if there is radial clearance in the transmission mechanism such as the reducer, a large radial impact will cause problems with NVH, reliability, etc.

[0031] This disclosure mainly relates to a test device for an electric drive system including an interconnected motor and a reducer. Based on the actual transmission conditions of the electric drive system, it tests the driving characteristics of the motor and reducer under typical conditions without affecting the normal driving of the vehicle. It can provide the most effective improvement measures and directions for the calibration of the electric drive system and the design of the reducer.

[0032] like Figure 1 As shown, the electric drive system here includes an interconnected motor 10 and a reducer 20. In one embodiment, the reducer 20 includes a differential assembly 41, a first-stage reduction gear pair 42, and a second-stage reduction gear pair 43. Of course, the reducer 20 can adopt any other structure. The test device for the electric drive system includes at least a temperature sensor 1, a rotor spindle 2, a reducer input shaft 3, an annular rotor transmitter 4, an annular stator receiver 5, and a speed sensor 6. In addition, the test device also includes test leads 9, a data acquisition unit 7, a power supply unit 14, and a CAN communication device. The temperature sensor 1, the annular rotor transmitter 4, the annular stator receiver 5, and the speed sensor 6 are all connected to the data acquisition unit 7, which is connected to the power supply unit 14. It can transmit signals with the vehicle's controller via the CAN communication device based on the CAN bus.

[0033] Specifically, the temperature sensor 1 is an electromagnetic interference resistant temperature sensor 1. The temperature sensor 1 is connected to the annular rotor transmitter 4 through the test wire 9. It is used to detect the temperature of the magnet 12 in the rotor of the motor 10, thereby accurately obtaining the temperature rise characteristics of the rotor of the motor 10. In this embodiment, four temperature sensors 1 are preferably used. The four temperature sensors 1 can be evenly arranged axially in the gaps of the magnet 12 in the rotor of the motor 10. They can be encapsulated and fixed in the magnet 12 with high-strength casting adhesive. Specifically, the eight wires corresponding to the four temperature sensors 1 can be arranged along the radial and axial wire holes provided on the rotor spindle 2. After fixing, they are encapsulated and fixed with casting adhesive.

[0034] The rotor mandrel 2 can be installed in the rotor of the motor 10. It can be connected to the motor output shaft of the motor 10 or directly serve as the motor output shaft. It is a customized semi-hollow rotor mandrel 2, such as... Figure 2 As shown, a first spline 21 is provided at the shaft end of the rotor spindle 2, and a first torque strain gauge 22 is provided on the surface of the rotor spindle 2. The first torque strain gauge 22 is connected to the annular rotor transmitter 4 through a test lead 9. After the rotor spindle 2 is calibrated and data is acquired using the first torque strain gauge 22, the motor output torque signal acquired by the first torque strain gauge 22, along with the temperature signal, is transmitted to the annular rotor transmitter 4 through the test lead 9. In this way, accurate testing based on the calibration steps can eliminate vehicle malfunctions caused by transmission backlash.

[0035] The reducer input shaft 3 can be adapted to any type of reducer. A second spline 31 is provided at its shaft end, which mates with the first spline 21 on the rotor spindle 2. A second torque strain gauge 32 is provided on the reducer input shaft 3. The reducer input torque collected by the second torque strain gauge 32 is the same as the motor output torque, and is tested in practice after calibration. The first torque strain gauge 22 and the second torque strain gauge 32 are used to measure the torque of the rotor spindle 2 and the reducer input shaft 3, respectively. This allows for spline strength analysis and improvement, thereby accurately simulating real vehicle operating conditions on a test bench.

[0036] The annular rotor transmitter 4 is based on a flexible transmitting circuit board and is fixed to the rotor spindle 2 by, for example, an annular tooling. In this embodiment, two sets of the annular rotor transmitter 4 may be used. The annular stator receiver 5 is disposed opposite to the annular rotor transmitter 4. The annular stator receiver 5 is fixed inside the housing of the motor 10 and the housing of the reducer 20 by, for example, a sensor bracket 8. Its placement is determined according to the position of the motor stator 13, and it may be coaxially disposed with the annular rotor transmitter 4. In this embodiment, two sets of the annular stator receiver 5 may be used.

[0037] In one embodiment, the annular rotor transmitter 4 and the annular stator receiver 5 are respectively a laser transmitter and a laser receiver; the laser receiver is disposed on the side of the motor housing 11 near the rotor; the laser transmitter is disposed on the rotor; the laser transmitter and the laser receiver are positioned opposite each other. When the hub motor is horizontally stationary, the laser transmitter emits laser light, and the laser receiver records the coordinate points as a standard point; during testing, the laser transmitter emits laser light, and the laser receiver collects the coordinate points and compares them with the standard points to obtain the horizontal status of the hub motor's fixed shaft. Using laser detection allows for rapid and accurate detection of the motor's horizontal status, facilitating rapid response in adjusting the motor's level.

[0038] In addition, a speed sensor 6 is installed on the sensor bracket 8. The speed sensor 6 is, for example, a Hall sensor. Preferably, two sets of speed sensors 6 are used to test the speed of the rotor spindle 2 and the speed of the reducer input shaft 3, respectively. The speed of the rotor spindle 2, i.e. the speed of the motor output shaft, is measured by the speed sensor 6 on the first spline 21 on the rotor spindle 2. The speed of the reducer input shaft 3 is also measured by the speed sensor 6 on the second spline 31 customized at the front end of the reducer input shaft 3.

[0039] The embodiments disclosed herein can accurately test key signals of the electric drive system in actual vehicle conditions, such as the temperature of the magnet 12, the rotational speed and torque of the rotor spindle 2 (or motor output shaft) and the reducer input shaft 3, as well as the CAN signal of the electric drive system, thereby performing comprehensive failure analysis, optimizing the electric drive control strategy, and improving the overall vehicle performance.

[0040] Based on the testing apparatus described in the above embodiments, the manufacturing and installation methods of the testing apparatus are as follows:

[0041] S101, fabricate the rotor spindle 2 for the motor 10. Specifically, without the magnet 12 installed, machine a blind hole with a diameter of 20mm along the central axis of the rotor spindle 2 until the starting position of the first spline 21 at the end of the rotor spindle 2; at the same time, evenly arrange four central holes with a radial diameter of 3mm at the mating position of the rotor spindle 2 and the magnet 21 of the motor 10, and open a 5mm diameter hole at the end of the rotor spindle 2 to facilitate the arrangement of the test wire 9;

[0042] S102, a second spline 31 is provided at the shaft end of the reducer input shaft 3. Specifically, a second spline 31 with a length of 5mm is provided at the front end of the reducer input shaft 3. In order to improve the speed test accuracy, the number of teeth of the second spline 31 is recommended to be 1.5 times the number of teeth of the first spline 21 at the shaft end of the rotor spindle 2. The probe of the second speed sensor 6 is aligned with the second spline 21.

[0043] S103, for the dual shafts, heat treatment and other processes are carried out, and the rotor spindle 2 and the reducer input shaft 3 are heat treated and gears are ground according to the processing technology.

[0044] S104, the temperature sensor 1 is encapsulated. Specifically, while pressing the magnetic steel sheet 12 into the motor 10, four temperature sensors 1 are encapsulated in the gaps of the magnetic steel sheet 12 with quick-drying adhesive and casting adhesive, so that they are evenly arranged in the radial direction. The test lead 9 is arranged and fixed along the aperture.

[0045] S105, Encapsulating sensor wires. Specifically, in order to withstand the high temperature and high speed test environment, all test wires 9 are arranged along the machined holes. Finally, the test wires 9 are led out from the first spline 21 of the rotor spindle 2 to the position of the annular rotor transmitter 4. Then, high temperature resistant casting glue is used to encapsulate and fill all the holes, and then the holes are dried.

[0046] S106, Install the annular rotor transmitter 4. Specifically, fix the first annular rotor transmitter and the second annular rotor transmitter onto the rotor spindle 2 and the reducer input shaft 3 respectively using annular tooling. Weld the wire harness of the temperature sensor 1 and the torque strain gauge wire harness, etc., and encapsulate the annular rotor transmitter 4 with high-strength epoxy resin.

[0047] S107, Install the annular stator receiver 5. Specifically, fix the first annular stator receiver and the second annular stator receiver to the housing 11 of the motor 10 and the housing 23 of the reducer 20 respectively through the sensor bracket 8. It is required that each pair of annular rotor transmitters 4 and annular stator receivers 5 are arranged coaxially and symmetrically to ensure a radial gap of 50mm on one side.

[0048] S108, Fixed speed sensor 6, specifically, the probes of the first speed sensor and the second speed sensor are fixed to the first spline 21 at the shaft end of the rotor spindle 2 and the second spline 31 at the shaft end of the reducer input shaft 3 respectively through the sensor bracket 8, ensuring a radial clearance of 2mm between them and the spline, which can be adjusted by testing the stability of the signal;

[0049] S109, Signal integration and acquisition, specifically, the temperature signal of the temperature sensor 1, the speed and torque signals of the rotor spindle 2 and the reducer output shaft, the CAN signal of the electric drive system bus, etc. are connected to the data acquisition instrument 7 to acquire the required signals in the same time domain;

[0050] S110, signal integration acquisition and debugging, specifically, after all sensor devices, wires, etc. are fixed and packaged, all signal debugging is carried out on the assembled electric drive system assembly. After the assembly is installed on the vehicle, typical working condition testing begins.

[0051] The second embodiment of this disclosure relates to an electric drive system, which includes a motor and a reducer connected to each other, and the electric drive system also includes the testing device for the electric drive system described in the above embodiments.

[0052] This disclosure enables real-time and accurate testing and calibration of the rotor temperature, torque, and speed of the electric drive system under typical road conditions. It solves vehicle-wide problems such as motor thermal performance issues and abnormal noise or failure of the reducer's power coupling, fundamentally addressing the performance and durability issues of the electric drive system, saving significant development costs and greatly shortening the verification cycle. This disclosure also enables precise testing and processing of the actual coupling state of the motor and reducer at high speeds, overcoming the limitations of previous inaccurate bench tests of reducer output torque and speed, and CAE simulations that could not accurately simulate the real-world conditions of a vehicle. This improves the comfort and reliability of the electric drive system.

[0053] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features disclosed in this disclosure that have similar functions.

[0054] Furthermore, while the operations are described in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or in a sequential order. In certain environments, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this disclosure. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0055] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.

[0056] The foregoing has provided a detailed description of several embodiments of this disclosure. However, this disclosure is not limited to these specific embodiments. Those skilled in the art can make various variations and modifications based on the concept of this disclosure, and all such variations and modifications should fall within the scope of protection claimed by this disclosure.

Claims

1. A testing apparatus for an electric drive system, the electric drive system comprising a motor and a reducer interconnected, characterized in that, The testing device includes a temperature sensor, a rotor mandrel, a reducer input shaft, an annular rotor transmitter, an annular stator receiver, and a speed sensor. The temperature sensor is evenly arranged axially in the gaps between the magnets in the rotor of the motor and is used to detect the temperature of the magnets. Torque strain gauges are disposed on the surfaces of the rotor mandrel and the reducer input shaft. The temperature sensor and the torque strain gauges are connected to the annular rotor transmitter via test wires. The annular stator receiver is disposed opposite to the annular rotor transmitter, and the horizontal condition of the motor is detected by laser detection using the annular stator receiver and the annular rotor transmitter. A first spline is disposed at the end of the rotor mandrel, and a second spline is disposed at the end of the reducer input shaft. The second spline mates with the first spline. The speed sensor is positioned opposite the first spline and the second spline, and measures the torque of the rotor mandrel and the reducer input shaft using the torque strain gauges and analyzes the spline strength based on the torque. The testing device also includes a data acquisition unit, and the temperature sensor, the annular rotor transmitter, the annular stator receiver, and the speed sensor are all connected to the data acquisition unit.

2. The testing apparatus according to claim 1, characterized in that, The testing device also includes a CAN communication device, through which the data acquisition instrument communicates with the vehicle's controller.

3. The testing apparatus according to claim 1, characterized in that, The wires corresponding to the temperature sensor are arranged along the radial and axial wire holes provided on the rotor spindle.

4. The testing apparatus according to claim 1, characterized in that, The annular rotor transmitter is based on a flexible transmitter circuit board, which is fixed to the rotor spindle by an annular tooling.

5. The testing apparatus according to claim 1, characterized in that, The annular stator receiver is fixed inside the housing of the motor and the housing of the reducer by a sensor bracket.

6. The testing apparatus according to claim 1, characterized in that, The annular stator receiver and the annular rotor transmitter are coaxially arranged.

7. The testing apparatus according to claim 1, characterized in that, The speed sensor is mounted on the sensor bracket and is used to test the speed of the rotor spindle and the input shaft of the reducer, respectively.

8. An electric drive system, characterized in that, The test apparatus includes any one of claims 1-7.

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