A wheel hub bearing load under rotation torque detection device and testing method

Abstract

This invention relates to the field of bearing testing technology, specifically disclosing a device for detecting the rotational torque of a wheel hub bearing under load. The device includes a driver, a support shaft, and a data acquisition unit. It also includes a front support assembly, an intermediate loading assembly, and an end support assembly mounted axially along the support shaft. Both the front and end support assemblies include support bearings and bushings. The inner ring of the support bearing is fixed to the support shaft, and the outer ring is fixed to the bushing. The end support bearing is the wheel hub bearing under test. The intermediate loading assembly includes an intermediate bearing and a load-bearing body. The load-bearing body bears the applied load. The data acquisition unit collects the torque and rotational speed of the support shaft. When testing the rotational torque of the wheel hub bearing, the sum of the torques of the intermediate bearing and the front support bearing under the corresponding load, temperature, and rotational speed needs to be subtracted. This solution addresses the problem of inaccurate testing of the rotational torque of wheel hub bearings under load in current methods.

Description

Technical Field

[0001] This invention relates to the field of bearing testing technology, specifically to a device and method for detecting the rotational torque of a wheel hub bearing under load. Background Technology

[0002] The rotational torque of automotive wheel hub bearings is a key aspect of wheel hub bearing design. Higher rotational torque leads to more severe bearing overheating, while lower torque fails to provide a proper seal. Since modern new energy vehicles are battery-powered, higher wheel hub bearing rotational torque results in a relatively lower battery range. Therefore, measuring the rotational torque of wheel hub bearings is crucial.

[0003] In existing technologies, there are three common methods for testing the rotational torque of wheel hub bearings. The first method involves subjecting the outer ring of the wheel hub bearing to an external load while the inner ring rotates, and then measuring the torque of the wheel hub bearing. For example, in a test bench for the frictional torque of an automotive wheel hub bearing with patent publication number CN104111170A, both the radial loading mechanism and the axial loading mechanism apply force to a fixed bracket, and then transmit the force to the stationary outer ring of the bearing under test through the fixed bracket. However, in actual use of automobiles, the load is applied to the inner ring, so this method cannot simulate the stress situation of the wheel hub bearing under actual working conditions.

[0004] The second method involves applying an external load to the inner ring of the wheel hub bearing and controlling its rotation to measure the torque of the outer ring. Examples include a wheel hub bearing dynamic friction torque testing bench (patent publication number CN109187014B) and a wheel hub unit friction torque testing machine (patent publication number CN217930800U). However, both of these technologies measure the torque of the outer ring of the wheel hub bearing, while in reality, the inner ring is the part that directly bears the torque. This results in inaccurate measurements of the rotational torque of the wheel hub bearing under load.

[0005] The third method involves applying an external load to the outer ring of the wheel hub bearing and controlling the rotation of the inner ring to measure the torque of the outer ring. However, since the actual working condition of the wheel hub bearing is that the inner ring bears the load, the test cannot simulate the actual working condition and the test is inaccurate.

[0006] How to effectively and accurately detect the rotational torque of wheel hub bearings under load is a major challenge in the bearing industry. Summary of the Invention

[0007] The present invention aims to provide a device for detecting the rotational torque of wheel hub bearings under load, so as to solve the problem of inaccurate testing of the rotational torque of wheel hub bearings under load in the current method.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A device for detecting the rotational torque of a wheel hub bearing under load includes a driver, a support shaft, and a data acquisition unit. The driver drives the support shaft to rotate. The device also includes a first-end support assembly, an intermediate loading assembly, and an end support assembly installed sequentially along the axial direction of the support shaft. Both the first-end and end support assemblies include a support bearing and a fixedly mounted bushing. The inner ring of the support bearing is fixed to the support shaft, and the outer ring of the support bearing is fixedly mounted to the bushing. The two bushings are coaxially mounted. The support bearing located at the end of the support shaft is the wheel hub bearing under test. The intermediate loading assembly includes an intermediate bearing and a load-bearing body. The intermediate bearing is located between the load-bearing body and the support shaft. The load-bearing body is used to bear the external load. The data acquisition unit is used to acquire the torque and rotational speed of the support shaft.

[0010] The principle and advantages of this scheme are as follows: When testing the rotational torque of a wheel hub bearing, the inner ring is fixed to the support shaft, which is directly driven by the driver. Therefore, the inner ring of the wheel hub bearing under test rotates. During this rotation, the total torque of the support shaft is recorded in real time. Since the support shaft is fixedly connected to the inner ring of the bearing under test, the inner ring of the first-stage support bearing, and the inner ring of the intermediate bearing, the remaining torque after subtracting the torques of the first-stage support bearing and the intermediate bearing is the torque of the inner ring of the wheel hub bearing under test, which is the measured rotational torque of the bearing under test. Compared to existing technologies, this scheme loads the load through the carrier in the middle of the support shaft, and the load is transmitted to the support shaft via the intermediate bearing, and then to the inner ring of the wheel hub bearing under test. This means the inner ring of the wheel hub bearing under test is under load, and the measured torque of the inner ring perfectly matches the actual vehicle condition where the inner ring of a wheel hub bearing is under load and requires rotational torque to drive its rotation, ensuring the accuracy and rationality of the test.

[0011] In addition, in this scheme, the bushings of the first and last support components are installed coaxially, ensuring that the outer ring of the tested wheel hub bearing is concentric with the first support bearing. The inner rings of the first and last support bearings (i.e., the tested wheel hub bearing) are coaxially fixed on the support shaft, thus ensuring the concentricity of the inner and outer rings of the tested wheel hub bearing and ensuring the installation accuracy of the tested wheel hub bearing, which is beneficial to improving the testing accuracy of this scheme.

[0012] Preferably, as an improvement, both the bushing and the carrier are provided with radial mounting holes, which are directly opposite the support bearing or the intermediate bearing, and are used to install temperature sensors; it also includes a closed test chamber, in which the first end support assembly, the intermediate loading assembly and the last end support assembly are all located.

[0013] Beneficial effects: The installation holes facilitate the installation of temperature sensors, which can be inserted into the outer rings of the support bearing and intermediate bearing. During the rotational torque detection process, the sample chamber simulates the test environment, and the temperature sensors monitor the surface temperature of each bearing in real time under the corresponding test environment.

[0014] Preferably, as an improvement, the force center of the support bearing of the first end support assembly and the force center of the support bearing of the last end support assembly are symmetrical about the intermediate loading assembly.

[0015] Beneficial effects: By setting the force centers of the support bearings at the front and rear ends symmetrically about the intermediate loading component, the support bearings can better and more accurately simulate the actual vehicle conditions, resulting in more accurate test results.

[0016] Furthermore, the design of this scheme allows for easy calculation of the sum of the rotational torques of the intermediate bearing and the first-end support bearing after all the support bearings are replaced with bearings identical to the intermediate bearing. This facilitates accurate calculation of the rotational torque of the tested wheel hub bearing during rotational torque testing.

[0017] Preferably, as an improvement, a transfer plate is fixedly installed between the inner ring of the test wheel hub bearing and the support shaft. The end face of the transfer plate away from the test wheel hub bearing abuts against the end face of the inner ring of the intermediate bearing, and the other end face of the inner ring of the intermediate bearing abuts against a step provided on the support shaft.

[0018] Beneficial effects: The adapter plate of this solution can fix the inner ring of the tested wheel hub bearing on the one hand, and on the other hand, the adapter plate and the step on the support shaft can limit the axial direction of the inner ring of the intermediate bearing.

[0019] Preferably, as an improvement, the bushing includes an inner bushing and an outer bushing that are fixedly connected. The outer bushing is fixedly connected to the test chamber, and the inner bushing is fixedly connected to the support bearing. The inner bushing of the first-end support assembly is provided with an installation groove for accommodating the outer ring of the support bearing. A pressure plate is fixedly connected to the inner bushing of the first-end support assembly for pressing the outer ring of the support bearing against the installation groove. The wall of the installation groove is provided with an annular groove, and a sealing ring is interference-fitted between the annular groove and the outer ring of the support bearing.

[0020] Beneficial effects: This solution, through the cooperation of inner and outer bushings, the connection between the bushing and the corresponding bearing outer ring, and the fixed connection with the test chamber, as well as the setting of the mounting groove and pressure plate, facilitates the axial limitation of the outer ring of the support bearing. The setting of the sealing ring on the annular groove ensures that the support bearing will not slip circumferentially during the test, thus guaranteeing the accuracy of the test.

[0021] Preferably, as an improvement, the intermediate loading assembly further includes an outer spacer and an intermediate end cap. There are two intermediate bearings and two intermediate end caps. The two intermediate bearings and intermediate end caps are symmetrical about the outer spacer. The outer ring of the intermediate bearing is clamped by the intermediate end cap and the outer spacer. An annular groove is provided on the surface of the carrier that is in circumferential contact with the outer ring of the intermediate bearing. A sealing ring is interference-fitted between the annular groove and the outer ring of the intermediate bearing.

[0022] Beneficial effects: This solution limits the axial position of the intermediate pair of bearings by setting the outer spacer and the intermediate end cover. By installing a sealing ring on the annular groove, it ensures that the intermediate bearings will not slip circumferentially during the test, thus ensuring the accuracy of the test.

[0023] This invention also provides a method for testing the rotational torque of a wheel hub bearing under load, which uses a wheel hub bearing rotational torque detection device under load and includes the following steps:

[0024] S1. Obtain the rotational torque of the intermediate bearing and the support bearing of the head support assembly under different temperatures, different loads, and different speeds;

[0025] S2. The test is conducted using a wheel hub bearing under load torque detection device with the test wheel hub bearing installed. During the test, the temperature sensor collects the real-time temperature of the test wheel hub bearing, intermediate bearing and remaining support bearing, and the data acquisition unit collects the real-time speed and torque of the support shaft.

[0026] S3. Calculate the rotational torque of the tested wheel hub bearing: The rotational torque of the tested wheel hub bearing is equal to the torque of the support shaft minus the torque of the intermediate bearing and the support bearing of the first end support assembly under the corresponding load, temperature and speed.

[0027] Preferably, as an improvement, in step S1, the intermediate bearing and the support bearing of the first-end support assembly are identical bearings. The rotational torque of the intermediate bearing and the support bearing of the first-end support assembly under different temperatures, loads, and speeds is obtained through a bearing rotational torque calibration device. The specific steps are as follows:

[0028] S11. Select radial rolling bearings of the same size, clearance, and performance as test bearings. Install the test bearings on the bearing rotation torque calibration device. The number of bearings, bearing positions, and bearing inner and outer ring fixing conditions on the support shaft of the bearing rotation torque calibration device are exactly the same as those on the wheel hub bearing rotation torque detection device under load. The test bearings completely simulate the force conditions of the intermediate bearing and the support bearing on the first end support assembly. During the test, collect the torque M1 of the support shaft on the bearing rotation torque calibration device under the same temperature and load but different speeds. There are multiple sets of test temperatures and multiple sets of test loads during the test. After the test, obtain a database of support shaft torques under different temperatures, loads, and speeds.

[0029] S12. Calculate the torque and M2 of the intermediate bearing and the support bearing of the head support assembly. The torque and M2 are equal to ((N-1)*M1) / N.

[0030] Beneficial effects: By using a bearing rotation torque calibration device to calibrate the rotation torque of the intermediate bearing and the first-end support bearing used as test bearings, the number, position, and installation scheme of the bearings are exactly the same as those in the rotation torque test of the tested wheel hub bearing. This ensures the simplicity of the torque test of the intermediate bearing and the first-end support bearing, reducing the difficulty of obtaining the rotation torque of the intermediate bearing and the first-end support bearing under different temperatures, loads, and speeds. On the other hand, it ensures the consistency and accuracy of the rotation torque test of the test bearing and the rotation torque test of the tested wheel hub bearing.

[0031] In addition, in this scheme, all test bearings are selected as radial rolling bearings, which helps to reduce the difficulty of obtaining the rotational torque of the intermediate bearing and the support bearing, and at the same time makes the torque and test of the rotational torque of the intermediate bearing and the first end more accurate.

[0032] Preferably, as an improvement, the radial rolling bearing is a deep groove ball bearing.

[0033] Beneficial effects: Using deep groove ball bearings as auxiliary bearings (intermediate bearing and head support bearing) in the test of the rotational torque of the tested wheel hub bearing results in a smaller frictional torque of the auxiliary bearings, reducing their impact on the test results; and the use of grease-lubricated deep groove ball bearings ensures good working stability during the test, and eliminates the need to consider the lubrication oil circuit during the test, simplifying the structure of the testing device.

[0034] Preferably, as an improvement, the test chamber is provided with a cold air inlet and a cold air outlet, which are used to enable low-temperature circulation within the test chamber.

[0035] Beneficial effects: By setting up a test chamber with a cooling inlet and a cooling outlet, the test chamber can simulate the starting torque of the test wheel hub bearing at low temperature, which increases the test scenario and facilitates the detection of the starting torque of the test wheel hub bearing at low temperature. Attached Figure Description

[0036] Figure 1 This is a cross-sectional view of the rotating torque detection device under load of a wheel hub bearing according to an embodiment of the present invention.

[0037] Figure 2 This is a structural cross-sectional view of the bearing rotation torque calibration device used in the wheel hub bearing rotation torque test method under load according to an embodiment of the present invention.

[0038] Figure 3 for Figure 1 A cross-sectional view of the adapter plate in the diagram.

[0039] Figure 4 for Figure 3 The left view.

[0040] Figure 5 for Figure 1 A sectional view of the inner liner.

[0041] Figure 6 for Figure 5 The left view. Detailed Implementation

[0042] The following detailed description illustrates the specific implementation method:

[0043] The reference numerals in the accompanying drawings include: test chamber 1, cold air pipe 101, return air pipe 102, driver 2, support shaft 3, inner spacer 301, left-hand nut 302, torque and speed sensor 4, first end support assembly 50, support bearing 51, bushing 52, inner bushing 521, outer bushing 522, pressure plate 53, second sealing ring 54, intermediate loading assembly 60, intermediate bearing 61, carrier 62, outer spacer 63, intermediate end cover 64, first sealing ring 65, end support assembly 70, tested wheel hub bearing 71, adapter plate 72, flat washer 73, radial electric cylinder 80, and temperature sensor 5.

[0044] The basic implementation examples are as follows: Figures 1 to 6 As shown.

[0045] Combination Figure 1A device for detecting the rotational torque of a hub bearing under load includes a closed test chamber 1, a driver 2, a support shaft 3, and a data acquisition unit. The driver 2 is used to drive the support shaft 3 to rotate. The driver 2 is a drive motor. The data acquisition unit is a torque and speed sensor 4. The torque and speed sensor 4 is fixedly installed between the drive motor and the support shaft 3 through a coupling. The torque and speed sensor 4 is used to collect the torque and speed of the support shaft 3.

[0046] The support shaft 3 is sequentially equipped with a head support assembly 50, an intermediate loading assembly 60, and an end support assembly 70 from the power input end to the free end. Both the head support assembly 50 and the end support assembly 70 are fixedly connected to the test chamber 1 and serve to support the support shaft 3. The head support assembly 50, the intermediate loading assembly, and the end support assembly 70 are all located inside the test chamber 1. The test chamber 1 is equipped with a cold air inlet and a cold air outlet. A cold air pipe 101 is installed at the cold air inlet, and a return air pipe 102 is installed at the cold air outlet, connecting the high and low temperature chamber to the cold air inlet and outlet, enabling the test chamber 1 to achieve low-temperature circulation. The intermediate loading assembly 60 is used to apply radial loads, which are applied via a radial electric cylinder 80 fixedly installed on the test chamber 1.

[0047] The intermediate loading assembly 60 includes an intermediate bearing 61, a carrier 62, an outer spacer 63, and an intermediate end cap 64. The carrier 62 encloses the outer edge of the intermediate bearing 61, and the intermediate bearing 61 is located between the carrier 62 and the support shaft 3. The carrier 62 is used to bear the external radial load. The inner ring of the intermediate bearing 61 is interference-fitted onto the support shaft 3. The outer spacer 63 is located between the outer rings of the two intermediate bearings 61. There are two intermediate bearings 61 and two intermediate end caps 64, and both intermediate bearings 61 and intermediate end caps 64 are symmetrical about the outer spacer 63. The outer ring of the intermediate bearing 61 is clamped by the intermediate end cap 64 and the outer spacer 63. The intermediate end cap 64 is fixed to the carrier 62 by screws. An annular groove is machined on the surface of the carrier 62 that is in circumferential contact with the outer ring of the intermediate bearing 61. A first sealing ring 65 is interference-fitted between the annular groove and the outer ring of the intermediate bearing 61. In this embodiment, the carrier 62 is composed of an inner carrier and an outer carrier with flush end faces. The outer carrier fits the inner carrier, and the middle end cap 64 is fixed on the outer carrier. To ensure that the outer carrier and the inner carrier do not rotate relative to each other in the circumferential direction, a radial positioning screw hole is machined on the inner carrier. A stop pin can be installed on the positioning screw hole. A U-shaped groove is machined on the end face of the outer carrier near the positioning screw hole to prevent the part of the stop pin from protruding from the inner carrier.

[0048] The center of force of the support bearing 51 of the first support assembly 50 and the center of force of the support bearing of the last support assembly 70 are symmetrical about the intermediate loading assembly 60.

[0049] Both the first-end support assembly 50 and the last-end support assembly 70 include a support bearing and a fixedly mounted bushing 52. The inner ring of the support bearing is fixed on the support shaft 3, and the outer ring of the support bearing is fixedly mounted to the bushing 52. The bushing 52 of the first-end support assembly 50 and the bushing 52 of the last-end support assembly 70 are coaxially mounted.

[0050] Both the carrier 62 and the bushing 52 are machined with radial mounting holes. The number of mounting holes is equal to the sum of the number of bearings on the support shaft 3. The mounting holes are directly opposite the support bearing 51 or the intermediate bearing 61. The mounting holes are used to install the temperature sensor 5. The temperature sensor 5 is used to detect the real-time temperature of the outer ring of the corresponding bearing.

[0051] In this embodiment, the support bearing located at the end of the support shaft 3 is the test wheel hub bearing 71; an adapter plate 72 is fixedly installed between the inner ring of the test wheel hub bearing 71 and the support shaft 3. Specifically, the adapter plate 72 is interference-fitted to a section at the end of the support shaft 3, and a flat washer 73 is fixed to the end of the support shaft 3 by screws. The flat washer 73 further locks the position of the adapter plate 72 on the support shaft 3. The adapter plate 72 and the inner ring flange of the test wheel hub bearing 71 are fixedly connected by bolts and nuts, simulating the installation of the inner ring of the test wheel hub bearing 71 with the brake disc and wheel rim of a car.

[0052] In this embodiment, a protrusion is machined on the support shaft 3, and steps are formed on both sides of the protrusion of the support shaft 3. The left end face of the inner ring of the left intermediate bearing 61 near the test wheel hub bearing 71 is abutted by the adapter plate 72, while the right end face abuts against the step.

[0053] The bushing 52 includes an inner bushing 521 and an outer bushing 522 that are fixedly connected by screws. The outer bushing 522 is fixedly connected to the test chamber 1, and the inner bushing 521 is fixedly connected to the support bearing 51. The support bearing of the end support assembly 70 is the test wheel hub bearing 71. The inner bushing 521 of the end support assembly 70 is fixedly connected to the outer ring of the test wheel hub bearing 71 by screws or bolts to simulate the fixed connection between the outer ring of the test wheel hub bearing 71 and the automotive steering knuckle. In this embodiment, the inner bushing 521 of the end support assembly 70 is fixedly connected to the outer ring of the test wheel hub bearing 71 by screws.

[0054] Except for the tested wheel hub bearing 71, the intermediate bearing 61 installed on the wheel hub bearing under load rotational torque testing device and the support bearing 51 on the first end support assembly 50 are all the same bearing model, bearing size, clearance, and performance, and are selected from the same batch of production.

[0055] The inner bushing 521 of the first end support assembly 50 is machined with a mounting groove for accommodating the outer ring of the support bearing 51. A pressure plate 53 is fixedly connected to the inner bushing 521 of the first end support assembly 50 by screws. The pressure plate 53 is used to press the outer ring of the support bearing 51 against the mounting groove. An annular groove is also machined on the hole wall of the mounting groove. A second sealing ring 54 is interference-fitted between the annular groove and the outer ring of the support bearing 51.

[0056] The right end face of the intermediate bearing 61 on the right side is separated from the left end face of the support bearing 51 on the first end support assembly 50 by an inner spacer 301. The inner spacer is fitted on the support shaft 3, and the axial direction of the inner ring of the intermediate bearing 61 on the right side is defined by the step and the inner spacer 301.

[0057] A left-hand nut 302 is threaded onto the support shaft 3. The left-hand nut 302 and the inner spacer 301 are located on both sides of the support bearing 51 to form an axial constraint on the inner ring of the first end support bearing 51. In addition, to ensure that the first end support bearing 51 does not slip, the inner ring of the support bearing 51 is interference-fitted with the support shaft 3.

[0058] This embodiment also provides a method for testing the rotational torque of a wheel hub bearing under load, which requires the use of the aforementioned wheel hub bearing rotational torque testing device under load, and includes the following steps:

[0059] S1. Obtain the rotational torque of the intermediate bearing 61 and the support bearing 51 of the head support assembly 50 under different temperatures, loads, and speeds; the specific steps are as follows:

[0060] S11. Select deep groove ball bearings of the same batch with identical dimensions, clearance, and performance as test bearings. Install the four test bearings as follows: Figure 2 The bearing rotation torque calibration device shown has the same bearing quantity, bearing position, and bearing inner and outer ring fixing condition on the support shaft 3 as the hub bearing rotation torque detection device under load. The test bearing completely simulates the force conditions of the intermediate bearing 61 and the support bearing 51 on the first end support assembly 50; specifically: combined with Figure 2 The bearing rotation torque calibration device differs from the hub bearing rotation torque testing device under load in that "the end support assembly 70 is exactly the same as the first end support assembly 50 and is installed symmetrically. The bearing rotation torque calibration device simply replaces the original test hub bearing 71 with a support bearing that is exactly the same as the first end support assembly 50 for testing. Accordingly, to facilitate the installation of the support bearing on the end support assembly 70, the support shaft 3 is set to be longer on the support bearing at the installation end."

[0061] During the test, the outer ring temperature of each test bearing was monitored in real time by temperature sensor 5. The torque M1 of the support shaft 3 on the bearing rotation torque calibration device was collected when the bearing rotation torque was at the same temperature and load but different speeds. There were multiple sets of test temperatures and multiple sets of test loads during the test. After the test was completed, a database of the torque of the support shaft 3 under different temperatures, loads and speeds was obtained.

[0062] S12. Calculate the torque and M2 of the intermediate bearing 61 and the support bearing 51 of the head support assembly 50. The torque and M2 are equal to ((N-1)*M1) / N.

[0063] S2. Take the test wheel hub bearing 71 and the three test bearings that have been tested above. Use the test bearings as the intermediate bearing 61 and the support bearing 51 of the first end support assembly 50. Install the test bearings and the test wheel hub bearing 71 on the wheel hub bearing load rotation torque detection device for testing. During the test, the temperature sensor 5 collects the real-time temperature of the test wheel hub bearing 71, the intermediate bearing 61 and the remaining support bearing 51 during the test. The data acquisition unit collects the real-time rotation speed and torque M3 of the support shaft 3.

[0064] S3. Calculate the rotational torque of the tested wheel hub bearing 71: The rotational torque M4 of the tested wheel hub bearing 71 is equal to the torque M3 of the support shaft 3 minus the torque M2 of the intermediate bearing 61 and the support bearing 51 of the head support assembly 50 under the corresponding load, temperature and speed.

[0065] S4. Provide cold air to the test chamber 1 through the high and low temperature chamber, and control the ultra-low temperature of the test environment in the test chamber 1 to detect the starting torque of the test wheel hub bearing 71 at low temperature.

[0066] This embodiment allows for a complete simulation of the actual operating conditions of the tested wheel hub bearing 71 on a real vehicle, and ensures the accuracy of the rotational torque test of the tested wheel hub bearing 71.

[0067] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A kind of wheel hub bearing load under rotary torque detection device, including driver, support shaft and data acquisition unit, driver is used to drive support shaft rotation, it is characterized in that: It also includes a first-end support assembly, an intermediate loading assembly, and an end support assembly installed sequentially along the support shaft axis. Both the first-end and end support assemblies include support bearings and fixedly mounted bushings. The inner ring of the support bearing is fixed to the support shaft, and the outer ring of the support bearing is fixedly mounted to the bushing. The two bushings are coaxially mounted. The support bearing at the end of the support shaft is the test wheel hub bearing. The intermediate loading assembly includes an intermediate bearing and a load-bearing body. The intermediate bearing is located between the load-bearing body and the support shaft. The load-bearing body is used to bear the external load, and the data acquisition unit is used to collect the torque and speed of the support shaft. The force center of the support bearing in the first-end support assembly and the force center of the support bearing in the end support assembly are symmetrical about the intermediate loading assembly. It also includes a closed test chamber, within which the first-end support assembly, intermediate loading assembly, and end support assembly are all located. The intermediate loading assembly also includes an outer spacer and an intermediate end cap. There are two intermediate bearings and two intermediate end caps. The two intermediate bearings and intermediate end caps are symmetrical about the outer spacer. The outer ring of the intermediate bearing is clamped by the intermediate end cap and the outer spacer. An annular groove is provided on the surface of the carrier that is in circumferential contact with the outer ring of the intermediate bearing. A sealing ring is interference-fitted between the annular groove and the outer ring of the intermediate bearing.

2. A wheel hub bearing load down rotational torque detection device according to claim 1, characterized in that: Both the bushing and the carrier are provided with radial mounting holes, which are directly opposite the support bearing or intermediate bearing. The mounting holes are used to install temperature sensors.

3. The device for detecting the rotational torque of a wheel hub bearing under load according to claim 2, characterized in that: A transfer plate is fixedly installed between the inner ring of the tested wheel hub bearing and the support shaft. The end face of the transfer plate away from the tested wheel hub bearing abuts against the end face of the inner ring of the intermediate bearing, and the other end face of the inner ring of the intermediate bearing abuts against a step provided on the support shaft.

4. The device for detecting the rotational torque of a wheel hub bearing under load according to claim 3, characterized in that: The bushing includes an inner bushing and an outer bushing that are fixedly connected. The outer bushing is fixedly connected to the test chamber, and the inner bushing is fixedly connected to the support bearing. The inner bushing of the first end support assembly is provided with an installation groove for accommodating the outer ring of the support bearing. A pressure plate is fixedly connected to the inner bushing of the first end support assembly for pressing the outer ring of the support bearing against the installation groove. The wall of the installation groove is provided with an annular groove, and a sealing ring is interference-fitted between the annular groove and the outer ring of the support bearing.

5. A method for testing the rotational torque of a wheel hub bearing under load, characterized in that, The test is performed using the wheel hub bearing rotational torque detection device under load as described in any one of claims 1 to 4, comprising the following steps: S1. Obtain the rotational torque of the intermediate bearing and the support bearing of the first-end support assembly under different temperatures, loads, and speeds; the specific steps are as follows: S11. Select deep groove ball bearings of the same size, clearance, and performance from the same batch as test bearings. Install four test bearings on the bearing rotation torque calibration device. The number of bearings, bearing positions, and bearing inner and outer ring fixing conditions on the support shaft of the bearing rotation torque calibration device are exactly the same as the number of bearings, bearing positions, and bearing inner and outer ring fixing conditions on the wheel hub bearing rotation torque detection device under load. The test bearings completely simulate the force conditions of the intermediate bearing and the support bearing on the first end support assembly. The difference between the bearing rotation torque calibration device and the wheel hub bearing rotation torque testing device under load is that "the end support assembly and the head support assembly are exactly the same and symmetrically installed". The bearing rotation torque calibration device simply replaces the original wheel hub bearing under test with a support bearing that is exactly the same as the head support assembly for testing. During the test, the outer ring temperature of each test bearing was monitored in real time by a temperature sensor. The torque M1 of the support shaft on the bearing rotation torque calibration device was collected when the bearing rotation torque was at the same temperature and load but different speeds. There were multiple sets of test temperatures and multiple sets of test loads during the test. After the test was completed, a database of support shaft torques under different temperatures, loads and speeds was obtained. S12. Calculate the torque and M2 of the intermediate bearing and the support bearing of the head support assembly. The torque and M2 are equal to ((N-1)). M1) / N, where N represents the total number of bearings to be tested, and N equals 4; S2. Take the test wheel hub bearing and three test bearings that have been tested above. Use the test bearings as intermediate bearings and support bearings of the first end support assembly. Install the test bearings and the test wheel hub bearings on the wheel hub bearing load rotation torque detection device for testing. During the test, the temperature sensor collects the real-time temperature of the test wheel hub bearing, intermediate bearing and remaining support bearings. The data acquisition unit collects the real-time speed of the support shaft and the torque M3 of the support shaft. S3. Calculate the rotational torque of the tested wheel hub bearing: The rotational torque M4 of the tested wheel hub bearing is equal to the torque of the support shaft M3 minus the torque of the intermediate bearing and the support bearing of the first end support assembly under the corresponding load, temperature and speed, and M2.

6. The method for testing the rotational torque of a wheel hub bearing under load according to claim 5, characterized in that: The test chamber is equipped with a cold air inlet and a cold air outlet, which are used to achieve low-temperature circulation within the test chamber.

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