A torque detection structure and method for maintenance-free bearings in truck wheel hubs

Abstract

This invention discloses a torque detection structure for a maintenance-free truck wheel hub bearing, comprising a loading disc, a mandrel, and a tooling sleeve. The loading disc and tooling sleeve are respectively installed at both ends of the mandrel. The bearing to be tested is installed between the tooling sleeve and the mandrel. A connecting structure for fixing the inner ring of the bearing to be tested to the end of the mandrel is detachably connected to the beginning of the mandrel. The loading disc is provided with a loading structure for linkage with an external loading device to transmit axial and radial loads to the mandrel. A test sleeve is connected between the loading disc and the mandrel, and a test bearing is installed between the test sleeve and the mandrel. The mandrel is provided with a driving structure for driving the mandrel to rotate so that the bearing to be tested and the test bearing rotate synchronously, and a detection structure for detecting the torque value generated by the operation of the bearing to be tested. This invention solves the problem in the prior art of lacking a detection fixture for simulating the actual operating conditions and stress conditions of a truck wheel hub bearing and detecting the torque value.

Description

Technical Field

[0001] This invention relates to the field of wheel hub bearing technology, specifically to a torque detection structure for a maintenance-free truck wheel hub bearing. Background Technology

[0002] The torque performance of truck wheel hub maintenance-free bearings directly affects the safety and reliability of vehicle operation. Accurate testing of the torque value after applying load is a crucial step in evaluating bearing performance. However, current technology suffers from two main problems. First, there is a lack of specialized testing equipment capable of effectively simulating the actual operating conditions (such as axial and radial loads) and stress states of truck wheel hub bearings, making it difficult to accurately reflect the torque characteristics of the bearings during actual use. Second, even when relevant testing equipment exists, there is a common problem of not being able to effectively separate the torque values ​​of the additional test bearings from those of the bearing under test, resulting in insufficient accuracy of test results and making it difficult to reliably evaluate the actual performance of the bearings. This poses significant challenges to the quality inspection and performance optimization of truck wheel hub maintenance-free bearings. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a torque detection structure and method for maintenance-free truck wheel hub bearings, thereby solving the problem of the lack of a detection fixture in the prior art for simulating the actual operating and stress conditions of truck wheel hub bearings and detecting torque values.

[0004] To achieve the above objectives, the present invention provides a torque detection structure for a maintenance-free bearing for a truck wheel hub, comprising a loading disc, a mandrel, and a tooling sleeve. The loading disc and the tooling sleeve are respectively installed at both ends of the mandrel. A bearing to be tested is installed between the tooling sleeve and the mandrel. The mandrel has a detachable connection structure at its beginning for fixing the inner ring of the bearing to be tested to the end of the mandrel. The loading disc is provided with a loading structure for linkage with an external loading device to transmit axial and radial loads to the mandrel. A test sleeve is connected between the loading disc and the mandrel. A test bearing is installed between the test sleeve and the mandrel. The mandrel is provided with a driving structure for driving the mandrel to rotate so that the bearing to be tested and the test bearing rotate synchronously, and a detection structure for detecting the torque value generated by the rotation of the bearing to be tested.

[0005] The advantages of adopting the above technical solution are: the connection structure can firmly fix the inner ring of the bearing under test, preventing loosening during operation and affecting test stability; the loading structure transmits axial and radial loads to the mandrel through the loading disk to accurately simulate actual stress conditions; simultaneously, the test sleeve and test bearing cooperate to form a test system, reducing external interference; and the drive structure enables synchronous operation of the bearing under test and the test bearing, ensuring a consistent test environment, thereby allowing the detection structure to measure torque values ​​in real time. This overall structure solves the problem of lacking testing fixtures that simulate actual working conditions and stress states, improving the authenticity and reliability of the test.

[0006] The present invention further comprises: the loading disk is composed of a horizontal part and a vertical part, and the horizontal part and the vertical part are connected perpendicularly to each other; the loading structure includes an axial loading connecting rod for linkage with an external loading device to apply an axial load to the loading disk; the axial loading connecting rod is movably disposed on the vertical part and is arranged in the same direction as the mandrel.

[0007] The advantages of adopting the above technical solution are: the vertical connection between the horizontal and vertical parts of the loading disk enhances the structural rigidity and improves the stability of load transmission, while the axial loading connecting rod is movably set in the vertical part and in the same direction as the mandrel, ensuring that the axial load is accurately transmitted along the mandrel axis, avoiding test errors caused by load offset, realizing the directional and stable application of axial load, adapting to the linkage requirements of external loading equipment, and improving the accuracy and reliability of axial loading.

[0008] The invention further includes an adjustment assembly on the vertical section for adjusting the relative position between the axial loading connecting rod and the vertical section to simulate the actual wheel radius conditions during the operation of the wheel hub bearing. The adjustment assembly includes a transmission screw and an adjustment seat movably mounted on the transmission screw. The transmission screw includes a screw shaft and a fixed seat. The fixed seat is mounted on the top wall of the vertical section and the screw shaft is rotatably connected to the fixed seat. The adjustment seat has a through hole for the screw shaft to pass through. The through hole is threadedly engaged with the screw shaft to allow the adjustment seat to shift along the axis of the screw shaft when the screw shaft rotates. The screw shaft is perpendicular to the spindle and parallel to the vertical section. The axial loading connecting rod is movably connected to the adjustment seat.

[0009] The advantages of adopting the above technical solution are: the transmission screw of the adjustment component and the adjustment seat are threaded together, which can accurately adjust the position of the axial loading connecting rod. The screw shaft is perpendicular to the spindle and parallel to the vertical part to ensure that the adjustment direction is stable and controllable. By adjusting the position, the stress conditions under different wheel radii can be accurately simulated, which fits the actual operating scenario, improves the diversity and authenticity of the test conditions, meets different testing needs, and enhances the adaptability and flexibility of the structure.

[0010] The present invention further comprises: a swing groove is provided on the adjusting seat, a pin is rotatably connected in the swing groove, a swing head is provided at the end of the axial loading connecting rod, the swing head is swinging in the swing groove along the opening direction of the swing groove and the swing head is coaxially connected to the pin.

[0011] The advantages of adopting the above technical solution are: the swing groove of the adjusting seat cooperates with the pin to realize the swing adjustment of the axial loading connecting rod. The swing head swings along the swing groove and is coaxially connected with the pin, which can adapt to the angle change during the loading process, avoid the additional stress generated by the rigid connection, ensure smooth and unobstructed load transmission, reduce structural wear, and improve the stability of the loading process and the service life of the structure.

[0012] The present invention further includes: the loading structure includes two sets of radial loading connecting rods for linkage with external loading equipment to apply radial load to the loading disk; both ends of the horizontal part are connected to a force-bearing shaft; the force-bearing shaft is arranged perpendicularly to the horizontal part; the two radial loading connecting rods correspond one-to-one with the two force-bearing shafts and are arranged in cooperation; the load loading direction of the radial loading connecting rod is arranged perpendicularly to the force-bearing shaft.

[0013] The advantages of adopting the above technical solution are: the two sets of radial loading connecting rods are set one-to-one with the horizontal force axis to ensure uniform distribution of radial load, the force axis is perpendicular to the horizontal part, and the load direction of the radial loading connecting rod is perpendicular to the force axis, ensuring a reasonable radial force transmission path, avoiding test deviation caused by off-center loading, realizing stable application of multi-directional radial load, and improving the accuracy and reliability of radial load simulation.

[0014] The present invention further comprises: a mandrel sleeve fitted on the outer peripheral wall of the end of the mandrel; a test sleeve fitted on the mandrel sleeve and a test bearing installed between the test sleeve and the mandrel sleeve; a locking cover for stable connection between the mandrel sleeve and the end of the mandrel detachably connected between the mandrel sleeve and the end of the mandrel; a connecting bolt connecting the locking cover and the mandrel; a first locking nut threadedly connected to the outer peripheral wall of the mandrel sleeve; a retaining edge circumferentially opened on the outer peripheral wall of the mandrel sleeve; the retaining edge and the first locking nut forming a clamping and limiting position on the inner ring of the test bearing; and the test bearing being a paired tapered roller bearing.

[0015] The advantages of adopting the above technical solution are: in the above technology, the mandrel sleeve is stably connected to the mandrel through the locking cover, which enhances the overall rigidity of the structure, while the flange and the first locking nut combine to clamp and limit the inner ring of the test bearing, ensuring that it is installed firmly without loosening. The paired tapered roller bearing is adapted to the test conditions, improving the load-bearing capacity and operational stability, reducing the interference of test component shaking on the test, and ensuring the structural stability and reliability of the test system.

[0016] The present invention further comprises: the drive structure including a servo motor and an accelerator for cooperating with the servo motor; the output end of the servo motor is coaxially aligned with the spindle; a transmission shaft is connected to the outer wall of the locking cover; the transmission shaft is coaxially aligned with the spindle; and a coupling is connected between the output end of the servo motor and the transmission shaft.

[0017] The advantages of adopting the above technical solution are: the servo motor and the accelerator work together to provide a stable driving force to meet the power requirements of the spindle operation, and the coaxial setting of the transmission shaft and the spindle ensures the coaxiality of power transmission, thereby reducing power loss. The coupling connects the output end of the servo motor and the transmission shaft, reducing vibration interference in power transmission, realizing the synchronous and stable operation of the spindle and the bearings to be tested and the test bearings, and ensuring driving accuracy and smooth operation.

[0018] The present invention further includes a torque sensor, which is mounted on the drive shaft to receive and analyze the feedback torque value during the operation of the spindle.

[0019] The advantages of adopting the above technical solution are: the torque sensor installed on the drive shaft can receive the torque value fed back by the spindle in real time, shorten the signal transmission path, reduce signal loss, ensure the timeliness and accuracy of torque detection, provide reliable data support for the analysis of the torque value of the bearing under test, directly reflect the torque change during operation, and improve the reliability and accuracy of the detection results.

[0020] The present invention further comprises: the connecting structure including a second locking nut that is threadedly engaged with the outer peripheral wall of the mandrel's starting end and a retaining ring circumferentially formed on the outer peripheral wall of the mandrel's starting end; the retaining ring and the second locking nut cooperate to form a clamping limit on the inner ring of the bearing to be tested; and a flange connected to the tooling sleeve for linkage with the spindle of an external device so as to drive the tooling sleeve to rotate synchronously when the spindle of the external device rotates.

[0021] The advantages of adopting the above technical solution are: In this technology, the retaining ring and the second locking nut work together to clamp and limit the inner ring of the bearing under test, ensuring its secure installation without displacement and preventing loosening during operation that could affect testing accuracy. Meanwhile, the flange of the tooling sleeve is linked with the spindle of the external equipment, enabling synchronous rotation of the outer ring of the bearing under test. This accurately simulates the actual rotation conditions of the outer ring during operation, improving the adaptability of the structure to the external equipment and the realism of the simulated operating conditions.

[0022] The present invention further provides a test method based on a torque detection structure for a truck wheel hub maintenance-free bearing, comprising the following steps:

[0023] S1. Drive the external equipment spindle to rotate forward at a speed of V1 to drive the tooling sleeve to rotate synchronously through the flange. When the tooling sleeve rotates, it drives the outer ring of the bearing to be tested to rotate synchronously. Start the servo motor to drive the mandrel to rotate at a speed of V2. The rotation direction of the mandrel is set in the same direction as the rotation direction of the flange. Selectively drive the external loading device to apply load to the axial loading connecting rod or the radial loading connecting rod according to the test conditions, so that the load is transmitted to the mandrel through the loading plate. The torque sensor receives and detects the torque value fed back by the mandrel through the transmission shaft. At this time, the torque value detected by the torque sensor is T1=T2-T3, where T2 is the torque value generated by the operation of the bearing to be tested, and T3 is the torque value generated by the operation of the bearing to be tested.

[0024] S2. Drive the external equipment spindle to rotate forward at a speed of V1 to drive the tooling sleeve to rotate synchronously through the flange. When the tooling sleeve rotates, it drives the outer ring of the bearing to be tested to rotate synchronously. Start the servo motor to drive the mandrel to rotate at a speed of V2. The rotation direction of the mandrel is set opposite to the rotation direction of the flange. Selectively drive the external loading device to apply load to the axial loading connecting rod or the radial loading connecting rod according to the testing conditions, so that the load is transmitted to the mandrel through the loading plate. The torque sensor receives and detects the torque value fed back by the mandrel through the transmission shaft. At this time, the torque value detected by the torque sensor is T1=T2+T3, where T2 is the torque value generated by the operation of the bearing to be tested, and T3 is the torque value generated by the operation of the bearing to be tested.

[0025] S3. Based on steps S1 and S2, the torque value detected by the torque sensor is the torque value generated by the bearing under test under axial load, radial load or combined load conditions.

[0026] The advantages of adopting the above technical solution are: the above testing process can effectively separate the torque values ​​of the bearing under test and the test bearing by using the torque difference during rotation in the same direction and the sum of the torque values ​​during rotation in opposite directions, eliminating interference from the test component, and combining axial, radial or combined loads to realistically simulate actual stress conditions, ensuring that the test results can accurately reflect the torque characteristics of the bearing under test under different load conditions, improving the accuracy and reliability of the test results, and providing a valid basis for bearing performance evaluation. Attached Figure Description

[0027] Figure 1 This is a three-dimensional view from the forward perspective of the present invention;

[0028] Figure 2 This is a three-dimensional view from the reverse perspective of the present invention;

[0029] Figure 3 This is a side sectional view of the present invention. Detailed Implementation

[0030] This invention provides a torque testing structure for a maintenance-free bearing in a truck wheel hub, comprising a loading disk 1, a mandrel 2, and a tooling sleeve 3. The loading disk 1 and the tooling sleeve 3 are respectively installed at both ends of the mandrel 2. A bearing 21 to be tested is installed between the tooling sleeve 3 and the mandrel 2. The mandrel 2 has a detachable connection structure at its starting end for fixing the inner ring of the bearing to be tested to the end of the mandrel 2. The loading disk 1 is provided with a loading structure for linkage with an external loading device to transmit axial and radial loads to the mandrel 2. A test sleeve 4 is connected between the loading disk 1 and the mandrel 2. A test bearing 22 is installed between the test sleeve 4 and the mandrel 2. The mandrel 2 is provided with a mechanism for driving the mandrel 2 to rotate so that the bearing 21 to be tested and the test bearing 22 move synchronously. The rotating drive structure and the detection structure for detecting the torque value generated by the operation of the bearing 21 under test are included. The loading disk 1 is composed of a horizontal part 11 and a vertical part 12, and the horizontal part 11 and the vertical part 12 are connected perpendicularly to each other. The loading structure includes an axial loading connecting rod 5 for linkage with an external loading device to apply axial load to the loading disk 1. The axial loading connecting rod 5 is movably disposed on the vertical part 12 and is arranged in the same direction as the spindle 2. An adjustment component is provided on the vertical part 12 for adjusting the relative position between the axial loading connecting rod 5 and the vertical part 12 to simulate the wheel radius working condition of the actual operation of the wheel hub bearing. The adjustment component includes a transmission screw and an adjustment seat 51 movably disposed on the transmission screw. The lead screw includes a lead screw shaft 52 and a fixed seat 53. The fixed seat 53 is disposed on the top wall of the vertical part 12, and the lead screw shaft 52 is rotatably connected to the fixed seat 53. The adjusting seat 51 has a through hole 511 for the lead screw shaft 52 to pass through. The through hole 511 is threadedly engaged with the lead screw shaft 52 to allow the adjusting seat 51 to shift along the axis of the lead screw shaft 52 when the lead screw shaft 52 rotates. The lead screw shaft 52 is perpendicular to the spindle 2 and parallel to the vertical part 12. The axial loading connecting rod 5 is movably connected to the adjusting seat 51. The adjusting seat 51 has a swing groove 512, in which a pin 513 is rotatably connected. The end of the axial loading connecting rod 5 is provided with a swing head 514. The head 514 is oscillatingly positioned within the oscillating groove 512 along its opening direction, and the oscillating head 514 is coaxially connected to the pin shaft 513. The loading structure also includes two sets of radial loading connecting rods 6 for linkage with external loading equipment to apply radial loads to the loading disk 1. Both ends of the horizontal part 11 are connected to force-bearing shafts 61, which are perpendicular to the horizontal part 11. The two radial loading connecting rods 6 correspond one-to-one with the two force-bearing shafts 61 and are fitted together. The load loading direction of the radial loading connecting rods 6 is perpendicular to the force-bearing shafts 61. A mandrel sleeve 23 is fitted onto the outer peripheral wall of the end of the mandrel 2. A test sleeve 4 is fitted onto the mandrel sleeve 23, and a test bearing 22 is installed between the test sleeve 4 and the mandrel sleeve 23.A locking cover 24 for stable connection between the mandrel sleeve 23 and the end of the mandrel 2 is detachably connected to the mandrel sleeve 23. A connecting bolt 241 connects the locking cover 24 and the mandrel 2. A first locking nut 25 is threaded onto the outer peripheral wall of the mandrel sleeve 23. A retaining edge 26 is circumferentially provided on the outer peripheral wall of the mandrel sleeve 23. The retaining edge 26 and the first locking nut 25 combine to form a clamping and limiting position on the inner ring of the test bearing 22. The test bearing 22 is a paired tapered roller bearing. The drive structure includes a servo motor 7 and an accelerator 71 for cooperating with the servo motor 7. The output end of the servo motor 7 is coaxially aligned with the mandrel 2. A drive shaft 242 is connected to the outer wall of the locking cover 24. The drive shaft 242 is coaxially arranged with the spindle 2. A coupling 72 connects the output end of the servo motor 7 to the drive shaft 242. The detection structure includes a torque sensor 73, which is mounted on the drive shaft 242 to receive and analyze the torque values ​​fed back during the operation of the spindle 2. The connection structure includes a second locking nut 27 threaded to the outer peripheral wall of the beginning end of the spindle 2 and a retaining ring 28 circumferentially formed on the outer peripheral wall of the beginning end of the spindle 2. The retaining ring 28 and the second locking nut 27 cooperate to form a clamping and limiting position on the inner ring of the bearing 21 to be tested. A flange 29 is connected to the tooling sleeve 3 for linkage with the main shaft of an external device so that the tooling sleeve 3 rotates synchronously when the main shaft of the external device rotates.

[0031] A testing method based on the above technical structure includes the following steps:

[0032] S1. Drive the external equipment spindle to rotate forward at a speed of V1 to drive the tooling sleeve to rotate synchronously through the flange. When the tooling sleeve rotates, it drives the outer ring of the bearing to be tested to rotate synchronously. Start the servo motor to drive the spindle to rotate at a speed of V2, and ensure that the V1 value is more than ten times the V2 value. The rotation direction of the spindle is set in the same direction as the rotation direction of the flange. Selectively drive the external loading device to apply load to the axial loading connecting rod or the radial loading connecting rod according to the testing conditions, so that the load is transmitted to the spindle through the loading plate. The torque sensor receives and detects the torque value fed back by the spindle through the transmission shaft. At this time, the torque value detected by the torque sensor is T1=T2-T3, where T2 is the torque value generated by the operation of the bearing to be tested, and T3 is the torque value generated by the operation of the bearing to be tested.

[0033] S2. Drive the external equipment spindle to rotate forward at a speed of V1 to drive the tooling sleeve to rotate synchronously through the flange. When the tooling sleeve rotates, it drives the outer ring of the bearing to be tested to rotate synchronously. Start the servo motor to drive the mandrel to rotate at a speed of V2. The rotation direction of the mandrel is set opposite to the rotation direction of the flange. Selectively drive the external loading device to apply load to the axial loading connecting rod or the radial loading connecting rod according to the testing conditions, so that the load is transmitted to the mandrel through the loading plate. The torque sensor receives and detects the torque value fed back by the mandrel through the transmission shaft. At this time, the torque value detected by the torque sensor is T1=T2+T3, where T2 is the torque value generated by the operation of the bearing to be tested, and T3 is the torque value generated by the operation of the bearing to be tested.

[0034] S3. Based on steps S1 and S2, the torque value detected by the torque sensor is the torque value generated by the bearing under test under axial load, radial load or combined load conditions.

[0035] The overall operation flow of the above technical structure:

[0036] 1. Equipment assembly and fixing: Install the loading plate and tooling sleeve on both ends of the mandrel respectively. Install the bearing to be tested between the tooling sleeve and the mandrel. Clamp and limit the inner ring of the bearing to be tested through the connecting structure (the retaining ring and the second locking nut) to ensure its stable fixation. The test sleeve is placed on the mandrel sleeve at the end of the mandrel. Install the test bearing between the test sleeve and the mandrel sleeve. Clamp and limit the inner ring of the test bearing with the help of the retaining edge and the first locking nut. The locking cover is used to stably connect the mandrel sleeve and the mandrel through the connecting bolts.

[0037] 2. Loading and driving connection: The horizontal part of the loading plate is connected to the radial loading connecting rods at both ends of the force-bearing shaft. The vertical part is equipped with the axial loading connecting rod through the adjustment assembly (transmission screw, adjustment seat). The swing head at the end of the axial loading connecting rod is rotatably connected to the swing groove of the adjustment seat via the pin shaft. The servo motor and accelerator are connected to the transmission shaft at the end of the spindle through the coupling. The torque sensor is installed on the transmission shaft. The tooling flange is linked to the main shaft of the external equipment.

[0038] 3. Test Operation: First, the external equipment spindle rotates in the forward direction (V1), driving the tooling sleeve and the outer ring of the bearing under test through the flange. The servo motor drives the mandrel to rotate in the same direction (V2). The loading device applies load through the axial / radial loading connecting rod, and the torque sensor detects the torque value T1 = T2 - T3. Second, the external equipment spindle continues to rotate in the forward direction (V1), while the servo motor drives the mandrel to rotate in the reverse direction (V2). The loading device maintains the applied load, and the torque sensor detects the torque value T1 = T2 + T3. Simultaneously, during operation, the external loading device can be selectively opened and closed according to test requirements. This allows the external loading device to apply loads to the axial or radial loading connecting rod, or simultaneously to both, thereby simulating the axial and radial load conditions experienced by the bearing during actual operation.

[0039] 4. Results Acquisition: Based on the two-step test torque values, the torque values ​​of the bearing under test under axial, radial, or combined load conditions are obtained.

[0040] The external loading device and external device spindle mentioned above are existing technologies, so their structure and function will not be described in detail.

[0041] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. A torque testing structure for a maintenance-free bearing in a truck wheel hub, characterized in that: The device includes a loading disk, a mandrel, and a tooling sleeve. The loading disk and tooling sleeve are respectively installed at both ends of the mandrel. A bearing to be tested is installed between the tooling sleeve and the mandrel. The mandrel has a detachable connection structure at its starting end for fixing the inner ring of the bearing to be tested to the end of the mandrel. The loading disk is provided with a loading structure for linkage with an external loading device to transmit axial and radial loads to the mandrel. A test sleeve is connected between the loading disk and the mandrel. A test bearing is installed between the test sleeve and the mandrel. The mandrel is provided with a drive structure for driving the mandrel to rotate so that the bearing to be tested and the test bearing rotate synchronously, and a detection structure for detecting the torque value generated by the operation of the bearing to be tested. The drive structure includes a servo motor, and the detection structure includes a torque sensor. The tooling sleeve is connected with a flange for linkage with the spindle of an external device so that the tooling sleeve rotates synchronously when the spindle of the external device rotates. The device also includes a testing method, comprising the following steps: S1. Drive the external equipment spindle to rotate forward at a speed of V1 to drive the tooling sleeve to rotate synchronously through the flange. When the tooling sleeve rotates, it drives the outer ring of the bearing to be tested to rotate synchronously. Start the servo motor to drive the mandrel to rotate at a speed of V2. The rotation direction of the mandrel is set in the same direction as the rotation direction of the flange. Selectively drive the external loading device to apply load to the axial loading connecting rod or the radial loading connecting rod according to the test conditions, so that the load is transmitted to the mandrel through the loading plate. The torque sensor receives and detects the torque value fed back by the mandrel through the transmission shaft. At this time, the torque value detected by the torque sensor is T1=T2-T3, where T2 is the torque value generated by the operation of the bearing to be tested, and T3 is the torque value generated by the operation of the bearing to be tested. S2. Drive the external equipment spindle to rotate forward at a speed of V1 to drive the tooling sleeve to rotate synchronously through the flange. When the tooling sleeve rotates, it drives the outer ring of the bearing to be tested to rotate synchronously. Start the servo motor to drive the mandrel to rotate at a speed of V2. The rotation direction of the mandrel is set opposite to the rotation direction of the flange. Selectively drive the external loading device to apply load to the axial loading connecting rod or the radial loading connecting rod according to the testing conditions, so that the load is transmitted to the mandrel through the loading plate. The torque sensor receives and detects the torque value fed back by the mandrel through the transmission shaft. At this time, the torque value detected by the torque sensor is T1=T2+T3, where T2 is the torque value generated by the operation of the bearing to be tested, and T3 is the torque value generated by the operation of the bearing to be tested. S3. Based on steps S1 and S2, the torque value detected by the torque sensor is the torque value generated by the bearing under test under axial load, radial load or combined load conditions.

2. The torque testing structure for a maintenance-free truck wheel hub bearing according to claim 1, characterized in that: The loading disk is composed of a horizontal part and a vertical part, and the horizontal part and the vertical part are connected perpendicularly to each other. The loading structure includes an axial loading connecting rod for linkage with an external loading device to apply an axial load to the loading disk. The axial loading connecting rod is movably disposed on the vertical part and is arranged in the same direction as the mandrel.

3. The torque testing structure for a truck wheel hub maintenance-free bearing according to claim 2, characterized in that: The vertical section is equipped with an adjustment assembly for adjusting the relative position between the axial loading connecting rod and the vertical section to simulate the actual wheel radius conditions during the operation of the wheel hub bearing. The adjustment assembly includes a transmission screw and an adjustment seat movably mounted on the transmission screw. The transmission screw includes a screw shaft and a fixed seat. The fixed seat is mounted on the top wall of the vertical section and the screw shaft is rotatably connected to the fixed seat. The adjustment seat has a through hole for the screw shaft to pass through. The through hole is threadedly engaged with the screw shaft to allow the adjustment seat to shift along the axis of the screw shaft when the screw shaft rotates. The screw shaft is perpendicular to the spindle and parallel to the vertical section. The axial loading connecting rod is movably connected to the adjustment seat.

4. The torque testing structure for a maintenance-free truck wheel hub bearing according to claim 3, characterized in that: The adjusting seat is provided with a swing groove, and a pin is rotatably connected in the swing groove. The end of the axial loading connecting rod is provided with a swing head. The swing head is swinging in the swing groove along the opening direction of the swing groove and is coaxially connected with the pin.

5. The torque testing structure for a truck wheel hub maintenance-free bearing according to claim 2, characterized in that: The loading structure also includes two sets of radial loading connecting rods for linkage with external loading equipment to apply radial load to the loading disk. Both ends of the horizontal part are connected to a force-bearing shaft, which is set perpendicular to the horizontal part. The two radial loading connecting rods correspond one-to-one with the two force-bearing shafts and are set in cooperation. The load loading direction of the radial loading connecting rod is set perpendicular to the force-bearing shaft.

6. The torque testing structure for a truck wheel hub maintenance-free bearing according to claim 1, characterized in that: A mandrel sleeve is fitted onto the outer peripheral wall of the mandrel end. A test sleeve is fitted onto the mandrel sleeve, and a test bearing is installed between the test sleeve and the mandrel sleeve. A locking cover for stable connection between the mandrel sleeve and the mandrel end is detachably connected between the mandrel sleeve and the mandrel end. A connecting bolt is connected between the locking cover and the mandrel. A first locking nut is threaded onto the outer peripheral wall of the mandrel sleeve. A retaining edge is circumferentially opened on the outer peripheral wall of the mandrel sleeve. The retaining edge and the first locking nut combine to form a clamping and limiting position on the inner ring of the test bearing. The test bearing is a paired tapered roller bearing.

7. The torque testing structure for a truck wheel hub maintenance-free bearing according to claim 6, characterized in that: The drive structure includes an accelerator for cooperating with a servo motor. The output end of the servo motor is coaxially aligned with the spindle. A transmission shaft is connected to the outer wall of the locking cover. The transmission shaft is coaxially aligned with the spindle. A coupling is connected between the output end of the servo motor and the transmission shaft.

8. The torque testing structure for a truck wheel hub maintenance-free bearing according to claim 7, characterized in that: The torque sensor is mounted on the drive shaft to receive and analyze the feedback torque value during the operation of the spindle.

9. The torque testing structure for a truck wheel hub maintenance-free bearing according to claim 1, characterized in that: The connection structure includes a second locking nut that is threaded into the outer peripheral wall of the mandrel's starting end and a retaining ring that is circumferentially opened on the outer peripheral wall of the mandrel's starting end. The retaining ring and the second locking nut cooperate to form a clamping limit on the inner ring of the bearing to be tested.

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