An automatic measuring device and method for medium-large bearing dynamic and static friction torque

Abstract

The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field of bearing detection. The application discloses an automatic measuring device and a measuring method for dynamic and static friction torque of medium and large bearings, and belongs to the technical field

Description

TECHNICAL FIELD

[0001] The present application relates to an automatic measuring device and method for dynamic and static friction torque of medium and large bearings, belonging to the technical field of bearing detection. BACKGROUND

[0002] In the field of mechanical engineering, bearings are indispensable key components in many mechanical devices, and their performance directly affects the working efficiency and service life of the entire device. For medium and large bearings, accurate measurement of dynamic and static friction torque is particularly important, because these parameters directly reflect the friction characteristics of the bearing, and thus affect the energy consumption, noise and reliability of the device.

[0003] Currently, bearing friction torque measurement mainly adopts transmission measurement method (torque sensor as transmission body) and balance measurement method (friction torque is calculated by balancing torque). However, the existing technology has the following shortcomings: insufficient precision, traditional devices (such as hanging weights, dial gauges for manual measurement) are low in efficiency and are interfered by human factors, making it difficult to achieve high-precision dynamic measurement; limited applicability, most devices are designed for small bearings and cannot adapt to the size and load requirements of medium and large bearings; dynamic / static separation, existing devices need to measure dynamic and static torque in steps, lack of integrated measurement capability, resulting in long measurement period; low degree of automation, relying on manual adjustment of load, speed and data recording, unable to provide real-time feedback control.

[0004] Medium and large bearings require high rigidity, stability and sensor sensitivity of the measuring device due to their large size and high load. Existing equipment is prone to vibration errors at high speed and is difficult to simulate the friction torque characteristics under real working conditions.

[0005] Therefore, in the bearing industry, there is a need for an automatic device that is high in precision, efficiency, and simple and reliable to operate, and can perform high-precision dynamic and multi-point static measurement of the friction torque of a wide range of radial ball bearings. SUMMARY

[0006] The present application aims to provide an automatic measuring device and method for dynamic and static friction torque of medium and large bearings to solve the problems raised in the background.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] Compared to existing technologies, this invention provides an automatic measuring device for the dynamic and static friction torque of medium and large bearings. The device includes a control housing, a load-bearing assembly on top of the control housing, and a control unit on one side of the control housing. The load-bearing assembly has a movable plate that can move up and down. A rotary motor is connected to the bottom of the load-bearing assembly via a lower fixed frame. The output shaft of the rotary motor is equipped with a drive shaft system. A force sensor is used to measure the actual load on the bearing being measured. An inner ring fixing mandrel is provided at the top of the drive shaft system for fixing the inner ring of the bearing. A force sensor is mounted on the inner ring fixing mandrel. The movable plate... A torque sensor is connected to the upper surface of the bearing via an upper fixed frame. The torque sensor is used to obtain the average dynamic torque, torque range, and dynamic torque curve of the bearing under test during one revolution. A measuring shaft system is provided at the bottom of the torque sensor. The measuring shaft system is a high-precision air bearing. The bottom end of the measuring shaft system extends to the lower part of the moving plate and is fitted with a self-aligning assembly through two guide posts to reduce interference and ensure measurement accuracy. An outer ring loading fixture is provided at the bottom of the self-aligning assembly. The outer ring loading fixture can be quickly adjusted according to the bearing size. With the cooperation of the torque sensor and the force sensor, the dynamic and static friction torque of the bearing under test is measured.

[0009] Furthermore, the supporting component includes a granite workbench, the upper surface of which is connected to a top plate via four frames, and the movable plate is nested with the four frames.

[0010] Furthermore, a loading cylinder is provided between the self-aligning assembly and the measuring shaft system. The self-aligning assembly includes a first ball-and-socket outer ring, a self-aligning disc is provided on the lower surface of the first ball-and-socket outer ring, a second ball-and-socket outer ring is provided below the self-aligning disc, an inner ball is provided between the second ball-and-socket outer ring and the self-aligning disc, and the first ball-and-socket outer ring and the second ball-and-socket outer ring are connected by bolts.

[0011] Furthermore, a lifting motor is provided on one side of the top of the supporting component, and the lifting motor drives the moving plate to move by driving the ball screw.

[0012] Furthermore, the outer ring loading fixture includes a loading seat, the lower surface of which is slidably connected to three loading bars via three through grooves, the lower surface of which is slidably connected to a loading block via a groove, and the loading block is provided with a screw for limiting the movement of the loading block.

[0013] Furthermore, a turntable is rotatably connected inside the loading seat. A vortex-shaped rack is provided on the lower surface of the turntable. A toothed groove corresponding to the rack is opened on one side of the top of the loading bar. A gear one is provided on the upper surface of the turntable. A gear two is meshed inside the gear one. An adjusting arm is provided on the gear two. The top of the adjusting arm extends out of the loading seat.

[0014] A measurement method based on an automatic measuring device for dynamic and static friction torque of medium and large bearings, comprising the following steps:

[0015] Preliminary adjustments were made to the outer ring loading fixture based on the dimensions of the bearing to be tested;

[0016] Place the bearing to be tested on the inner ring fixed mandrel, and then control the moving plate to move down so that the outer ring loading fixture is close to the upper part of the outer ring of the bearing to be tested. Observe the gap of 2-5mm, and then clamp the outer ring of the bearing to be tested under the action of the outer ring loading fixture.

[0017] During testing, the dynamic torque measurement or multi-point static friction torque measurement of the bearing can be selected on the measurement software as needed. The rotating motor is controlled to work, and the friction torque is transmitted to the torque sensor and force sensor through the measurement shaft system. The friction torque of the bearing under test is then converted into an electrical signal, which is amplified and filtered before being sent to the control unit for calculation by the measurement software.

[0018] The control unit displays the calculated data, including dynamic measurement results, measurement curves, and pass / fail criteria.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] By adopting a measuring shaft system with air bearings, as well as torque and force sensors, the reference friction and measurement error are effectively reduced, and the measurement accuracy is improved. The entire measurement process is automatically completed by the control circuit and signal processing circuit, which reduces the influence of human factors and improves the repeatability and reliability of the measurement.

[0021] Suitable for medium and large bearings of various specifications, and can be adapted to bearings of different sizes by adjusting the outer ring loading fixture;

[0022] It can not only measure dynamic friction torque, but also automatically measure static friction torque at multiple points, providing the static torque distribution of the bearing within one revolution. This provides more comprehensive bearing friction characteristic data, which helps to optimize bearing design and selection. The operation is simple and the automated design makes it easy to operate without complicated operating procedures, reducing the technical requirements for operators. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a partial structural schematic diagram of the present invention;

[0026] Figure 3 for Figure 2 Structural sectional view;

[0027] Figure 4 This is a schematic diagram of the structure of the load-bearing component of the present invention;

[0028] Figure 5 This is an exploded view of the structure at the measuring shaft of the present invention;

[0029] Figure 6 This is an exploded view of the structure of the rotary motor of the present invention;

[0030] Figure 7 This is a schematic diagram of the structure at the inner ring fixing mandrel of the present invention;

[0031] Figure 8 This is an exploded view of the outer ring loading fixture of the present invention;

[0032] Figure 9 This is a schematic diagram of the electrical system of the present invention.

[0033] In the diagram: 1. Granite workbench; 2. Frame; 3. Top plate; 4. Moving plate; 5. Lifting motor; 6. Ball screw; 7. Lower fixed frame; 8. Rotary motor; 9. Drive shaft system; 10. Force sensor; 11. Inner ring fixed mandrel; 12. Upper fixed frame; 13. Torque sensor; 14. Measuring shaft system; 15. Loading cylinder; 16. Outer ring of the first ball socket; 17. Guide column; 18. Outer ring of the second ball socket; 19. Self-aligning plate; 20. Inner ball socket; 21. Outer ring loading fixture; 2101. Loading seat; 2102. Through groove; 2103. Loading bar; 2104. Groove; 2105. Loading block; 2106. Turntable; 2107. Rack; 2108. Gear 1; 2109. Gear 2; 2110. Adjusting arm; 22. Control box; 23. Control unit. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figures 1-9 The present invention provides a technical solution:

[0036] like Figures 1-3 , Figure 5 and Figure 6 As shown, an automatic measuring device for dynamic and static friction torque of medium and large bearings includes a control housing 22, a support assembly mounted on top of the control housing 22, and a control unit 23 mounted on one side of the control housing 22. The support assembly provides a platform for the installation and operation of other components. A movable plate 4 that can move up and down is mounted on the support assembly. A rotary motor 8 is connected to the bottom of the support assembly via a lower fixing frame 7. A drive shaft system 9 is mounted on the output shaft of the rotary motor 8. An inner ring fixing mandrel 11 for fixing the inner ring of the bearing is mounted on the top of the drive shaft system 9. A force sensor 10 is mounted on the inner ring fixing mandrel 11. The force sensor 10 is used to accurately measure the actual load applied to the bearing under test, providing key load data for subsequent measurement data analysis. The upper surface of the movable plate 4 is connected via an upper fixing frame 12. A torque sensor 13 is included, which is a key component for measuring the dynamic and static friction torque of a bearing. It can accurately measure the average dynamic torque, torque range, and dynamic torque curve of the bearing during one revolution, providing comprehensive data support for evaluating the dynamic friction performance of the bearing. A measuring shaft system 14 is provided at the bottom of the torque sensor 13. The measuring shaft system 14 is an air bearing. Air bearings have advantages such as low friction coefficient, high precision, and good stability, which can effectively reduce reference friction and measurement error and significantly improve measurement accuracy. The bottom end of the measuring shaft system 14 extends to the bottom of the moving plate 4 and is fitted with a self-aligning assembly through two guide posts 17. An outer ring loading fixture 21 is provided at the bottom of the self-aligning assembly. The self-aligning assembly can be aligned to ensure that the bearing is in the correct position during measurement and reduce the interference of the loading mechanism on the measurement.

[0037] Specifically, when measuring the frictional torque of a bearing, the measurement includes both dynamic frictional torque and static frictional torque:

[0038] When measuring dynamic friction torque, the rotary motor 8 drives the drive shaft system 9 to rotate, which in turn drives the inner ring of the bearing under test to rotate. The lifting motor 5 drives the outer ring loading fixture 21 to contact the outer ring of the bearing under test and apply a specified load to the bearing under test. The average dynamic torque, torque range and dynamic torque curve of the bearing under test during one revolution are measured by the torque sensor 13.

[0039] When measuring static friction torque, the number of measurement points within one revolution is set, and the load is gradually applied from small to large at a specified angular position to drive the bearing to rotate. The maximum torque peak value is measured, and the torque peak values ​​of each measurement point within one revolution are averaged to obtain the static friction torque of the bearing under test and the static torque distribution curve within one revolution.

[0040] Furthermore, a lifting motor 5 is installed on one side of the top of the support component. The lifting motor 5 drives the moving plate 4 to move by driving the ball screw 6. This driving method has the characteristics of high precision and good stability, which can ensure that the moving plate 4 can be accurately adjusted in position under different measurement conditions.

[0041] like Figure 8 As shown, in this embodiment, the electrical part of the automatic measurement device mainly consists of a computer, a motor control circuit, signal processing, a preamplifier and filter circuit, an A / D sampling circuit, and I / O input and output circuits.

[0042] The instrument uses a computer to control the entire measurement process. The computer first outputs through I / O and then through the motor control circuit to drive the mechanical mechanism to rotate, measuring the friction torque signal. All signals are processed and input to the computer via A / D converter. The computer then processes the data to obtain the bearing's friction torque value.

[0043] In one embodiment, the bearing starting friction torque detector has a small torque measuring device with an inner diameter of 80-350mm and the following technical specifications:

[0044] a) Measurement item: Starting torque (dynamic torque)

[0045] b) Measurement range: 0.2 Nm;

[0046] c) Indication error: ±0.002 Nm; Indication repeatability: 0.004 Nm;

[0047] d) Rotation speed: 1-10 rpm, with forward and reverse rotation error not exceeding ±1% of full scale;

[0048] e) Axial load range and accuracy: Range: 0-100N, Accuracy: ≤±2N;

[0049] f) Bearing inner diameter range: φ80—φ350mm

[0050] g) Measurement model (8 sets of tooling): 11 types including JMC001 in the table, requiring 8 sets of tooling (select one set of bearings in good condition according to the product situation, and the supplier shall provide a calibration certificate).

[0051]

[0052] Usage conditions:

[0053] ① Ambient temperature: 10℃~30℃ ② Relative humidity: ≤80%

[0054] ③ Power supply voltage: 220±10%V 50Hz ④ Air supply pressure: 0.55~0.65Mpa

[0055] In another embodiment, the bearing starting friction torque detector—a high torque measuring device—has an inner diameter of 80-500 mm and the following technical specifications:

[0056] a) Measurement item: Starting torque, i.e., dynamic torque

[0057] b) Measurement range: 2 N·m; 10 N·m; 100 N·m;

[0058] c) Indication error: ±0.02Nm, ±0.1Nm, ±1N.m; Repeatability: 0.04Nm, 0.2Nm, 2N.m; d) Speed: 1-5rpm, forward and reverse rotation error not greater than ±1% of full scale;

[0059] e) Axial load range and accuracy: Range: 0-1000N, Accuracy: ≤±20N;

[0060] f) Bearing size range: Inner diameter φ80—Outer diameter φ600mm

[0061] g) Measurement model (6 sets of tooling): The table lists 6 types including JMC012, requiring 6 sets of tooling (select one set of bearings in good condition according to the product situation, and the supplier shall provide a calibration certificate).

[0062]

[0063] like Figure 3 As shown, the supporting components include a granite workbench 1, the upper surface of which is connected to a top plate 3 via four frames 2, and a movable plate 4 is nested with the four frames 2.

[0064] like Figure 4 As shown, a loading cylinder 15 is provided between the self-aligning assembly and the measuring shaft system 14. The self-aligning assembly includes a first ball socket outer ring 16, a self-aligning disk 19 is provided on the lower surface of the first ball socket outer ring 16, a second ball socket outer ring 18 is provided below the self-aligning disk 19, an inner ball socket 20 is provided between the second ball socket outer ring 18 and the self-aligning disk 19, and the first ball socket outer ring 16 and the second ball socket outer ring 18 are connected by bolts.

[0065] like Figure 7As shown, the outer ring loading fixture 21 includes a loading seat 2101. Three loading bars 2103 are slidably connected to the lower surface of the loading seat 2101 via three through grooves 2102. Loading blocks 2105 are slidably connected to the lower surface of the loading bars 2103 via grooves 2104. A screw is provided on the loading block 2105 to limit its movement. A turntable 2106 is rotatably connected inside the loading seat 2101. A vortex-shaped rack 2107 is provided on the lower surface of the turntable 2106. A toothed groove corresponding to the rack 2107 is opened on one side of the top of each loading bar 2103. A gear 2108 is provided on the upper surface of the turntable 2106. Gear 2109 is internally meshed with 08. Gear 2109 is equipped with an adjusting arm 2110. The top of the adjusting arm 2110 extends into a loading seat 2101. Specifically, when the extrusion cover 1115 is separated from the lower surface of the outer ring loading fixture 21, rotating the adjusting arm 2110 can drive gear 2109 to rotate, thereby causing gear 1 2108 to drive the turntable 2106 to rotate. The rack 2107 on the turntable 2106 cooperates with the tooth groove on the loading bar 2103 to realize the movement of the loading bar 2103 and the loading block 2105, thereby loading the outer ring of the bearing. It can be adjusted according to the size and measurement requirements of different bearings.

[0066] A measurement method based on an automatic measuring device for dynamic and static friction torque of medium and large bearings, comprising the following steps:

[0067] The outer ring loading fixture 21 is initially adjusted according to the dimensions of the bearing to be tested;

[0068] Place the bearing to be tested on the inner ring fixing mandrel 11, and then control the moving plate 4 to move down so that the outer ring loading fixture 21 is close to the upper part of the outer ring of the bearing to be tested. Observe the gap of 2-5mm, and then clamp the outer ring of the bearing to be tested under the action of the outer ring loading fixture 21.

[0069] During testing, the dynamic torque measurement or multi-point static friction torque measurement of the bearing can be selected on the measurement software as needed, and the rotary motor 8 is controlled to work. Due to the existence of internal friction torque of the bearing and the fact that the measuring shaft system is a low-friction shaft system, this additional torque can be ignored. The friction torque of the bearing is used as the load torque. The friction torque is transmitted to the torque sensor and force sensor through the measuring shaft system. The friction torque of the bearing under test is then converted into an electrical signal, which is amplified and filtered before being sent to the control unit 23 for calculation by the measurement software.

[0070] The control unit 23 displays the calculated data, including dynamic measurement results, measurement curves, and pass / fail criteria.

[0071] Specifically, when the measurement software performs calculations on the amplified and filtered electrical signal, the specific calculation formulas include:

[0072] When measuring the dynamic torque of a bearing, the dynamic frictional torque refers to the total frictional resistance torque generated by the combined action of the rolling elements, cage, lubricant, and seals during bearing rotation. Its calculation is typically based on empirical formulas or industry standards, including the following formulas:

[0073] M = M0 + M1 + M2

[0074] Where M0 is the friction component that is independent of the load and is mainly generated by the viscous resistance of the lubricant;

[0075]

[0076] Where f0 is a coefficient related to the bearing type, obtained by looking up a table:

[0077] v represents the kinematic viscosity of the lubricant, measured in mm. 2 / s;

[0078] n represents the rotational speed, in r / min;

[0079] d m This refers to the bearing pitch circle diameter, in mm.

[0080] M1 is the friction component related to the load;

[0081] M1=f1·P1·d m

[0082] f1 is the coefficient of friction under load, which is usually taken as 0.0001-0.0005;

[0083] P1 is the equivalent dynamic load, in N;

[0084] M2 is the additional frictional torque of the seal.

[0085] Specifically, dynamic friction mainly originates from:

[0086] Elastic hysteresis between rolling elements and raceways: Microscopic deformation during rolling contact leads to energy loss.

[0087] Lubricant shear resistance: the shear flow of viscous fluid in a gap, i.e., viscous friction.

[0088] Cage friction: the sliding contact between the cage and the rolling elements / rings.

[0089] Seal resistance: friction between the rubber seal ring and the shaft.

[0090] When measuring multi-point static friction torque, the static multi-point friction torque refers to the total frictional resistance torque generated when a bearing is stationary or at extremely low speeds due to multiple rolling elements simultaneously bearing loads (such as radial load distribution). This is commonly seen in heavy-load or preloaded operating conditions. Specific formulas include:

[0091] Simplified formula under Hertzian contact theory

[0092]

[0093] Where N is the number of loaded rolling elements;

[0094] μ is the coefficient of sliding friction, which is usually taken as 0.001 to 0.005 and is related to surface roughness and lubrication conditions;

[0095] d m This refers to the bearing pitch circle diameter, in meters (m).

[0096] Q i The normal contact load of the i-th rolling element is in N and is determined by the load distribution model, such as the Stribeck distribution.

[0097] Specifically, the principle of multi-point static friction torque measurement includes:

[0098] Load distribution: Under static conditions, multiple rolling elements share the external load, such as about 1 / 3 of the rolling elements under radial load.

[0099] Sliding friction: Friction is caused by minute sliding in the contact area between the rolling element and the raceway.

[0100] Effects of preload: Preloaded bearings increase the contact angle, altering load distribution and friction torque.

[0101] When conducting tests, dynamic friction needs to take into account the effect of temperature rise on lubricant viscosity; static friction is particularly important in precision machinery and may affect positioning accuracy; the actual friction torque needs to be calibrated through experiments to calibrate the theoretical model.

[0102] The workflow of this embodiment is as follows: First, adjust the inner ring fixing mandrel 11 according to the size of the bearing to be tested to match the size of the bearing inner ring. Then, place the bearing inner ring on the inner ring fixing mandrel 11. Start the lifting motor 5, and drive the moving plate 4 to descend through the ball screw 6, so that the outer ring loading fixture 21 moves down. By rotating the adjusting arm 2110, the gear 2109 can be driven to rotate, which in turn drives the turntable 2106 to rotate through the gear 2108. The rack 2107 on the turntable 2106 and the tooth groove on the loading bar 2103 cooperate with each other to realize the movement of the loading bar 2103 and the loading block 2105, thereby loading the bearing outer ring. Start the loading cylinder 15 to apply a certain pressure to the outer ring loading fixture 21, so that the bearing is in a loaded state. Start the rotating motor. The motor 8 drives the shaft system 9 to rotate the inner ring of the bearing. During the rotation, the force sensor 10 measures the actual loaded load, and the torque sensor 13 measures the average dynamic torque, torque range, and dynamic torque curve during one revolution of the bearing. The measuring shaft system 14 uses an air bearing, which effectively reduces friction and measurement error and improves measurement accuracy. When it is necessary to measure the static friction torque, the rotating motor 8 is stopped. Through the control circuit and signal processing circuit, the static friction torque at multiple points is automatically measured, and the static torque distribution during one revolution of the bearing is recorded. After the measurement is completed, the pressure on the outer ring loading fixture 21 is released, and then the lifting motor 5 is started to raise the moving plate 4 to separate the outer ring loading fixture 21 from the outer ring of the bearing. Finally, the inner ring fixing mandrel 11 is released, and the bearing under test is taken out.

[0103] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An automatic measuring device for dynamic and static friction torque of medium and large bearings, characterized in that, The system includes a control housing, a support assembly on top of the control housing, and a control unit on one side of the control housing. The support assembly has a movable plate that can move vertically. A rotary motor is connected to the bottom of the support assembly via a lower fixed frame. The output shaft of the rotary motor is equipped with a drive shaft system. An inner ring fixing mandrel for fixing the inner ring of a bearing is located at the top of the drive shaft system. A force sensor is mounted on the inner ring fixing mandrel for measuring the actual load on the bearing under test. A torque sensor is connected to the upper surface of the movable plate via an upper fixed frame. The torque sensor is used to obtain the average dynamic torque, torque range, and dynamic torque curve of the bearing under test during one revolution. The bottom of the torque sensor is equipped with a measuring shaft system, which is a high-precision air bearing. The bottom of the measuring shaft system extends to the bottom of the moving plate and is connected to a self-aligning assembly through two guide posts to reduce interference and ensure measurement accuracy. The bottom of the self-aligning assembly is equipped with an outer ring loading fixture, which can be quickly adjusted according to the bearing size. With the cooperation of the torque sensor and the force sensor, the dynamic and static friction torque of the bearing under test can be measured. The outer ring loading fixture includes a loading seat, and three loading bars are slidably connected to the lower surface of the loading seat through three through grooves. Loading blocks are slidably connected to the lower surface of the loading bars through grooves. A screw for limiting the movement of the loading block is provided on the loading block. A turntable is rotatably connected inside the loading seat. A vortex-shaped rack is provided on the lower surface of the turntable. A toothed groove corresponding to the rack is opened on one side of the top of the loading rack. A gear one is provided on the upper surface of the turntable. A gear two is meshed inside the gear one. An adjusting arm is provided on the gear two. The top of the adjusting arm extends out of the loading seat. A loading cylinder is provided between the self-aligning assembly and the measuring shaft system. The self-aligning assembly includes a first ball-and-socket outer ring, a self-aligning disc is provided on the lower surface of the first ball-and-socket outer ring, a second ball-and-socket outer ring is provided below the self-aligning disc, an inner ball is provided between the second ball-and-socket outer ring and the self-aligning disc, and the first ball-and-socket outer ring and the second ball-and-socket outer ring are connected by bolts.

2. The automatic measuring device for dynamic and static friction torque of medium and large bearings according to claim 1, characterized in that, The supporting component includes a granite workbench, the upper surface of which is connected to a top plate via four frames, and the movable plate is nested with the four frames.

3. The automatic measuring device for dynamic and static friction torque of medium and large bearings according to claim 1, characterized in that, A lifting motor is provided on one side of the top of the bearing component, and the lifting motor drives the moving plate to move by driving the ball screw.

4. A measurement method based on the automatic measuring device for dynamic and static friction torque of medium and large bearings as described in any one of claims 1-3, characterized in that, The specific steps include: Preliminary adjustments were made to the outer ring loading fixture based on the dimensions of the bearing to be tested; Place the bearing to be tested on the inner ring fixed mandrel, and then control the moving plate to move down so that the outer ring loading fixture is close to the upper part of the outer ring of the bearing to be tested. Observe the gap of 2-5mm, and then clamp the outer ring of the bearing to be tested under the action of the outer ring loading fixture. During testing, the dynamic torque measurement or multi-point static friction torque measurement of the bearing can be selected on the measurement software as needed. The rotating motor is controlled to work, and the friction torque is transmitted to the torque sensor and force sensor through the measurement shaft system. The friction torque of the bearing under test is then converted into an electrical signal, which is amplified and filtered before being sent to the control unit for calculation by the measurement software. The control unit displays the calculated data, including dynamic measurement results, measurement curves, and pass / fail criteria.

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