Device and method for automatically measuring dynamic and static friction torques of medium and large bearings

Abstract

The invention discloses an automatic measuring device and measuring method for dynamic and static friction torques of medium and large-sized bearings, and belongs to the technical field of bearing detection.The device comprises a bearing assembly, a moving plate is arranged on the bearing assembly, a rotating motor is connected to the bottom of the bearing assembly, and a driving shaft system is arranged on an output shaft of the rotating motor; the top end of the driving shaft system is provided with an inner ring fixing mandrel, the upper surface of the moving plate is connected with a torque sensor through an upper fixing frame, the bottom end of the torque sensor is provided with a measuring shaft system, the bottom end of the measuring shaft system is sleeved with a center adjusting assembly through two guide columns, the bottom of the center adjusting assembly is provided with an outer ring loading tool, and the outer ring loading tool is provided with an inner ring. Under the cooperation of the structure, not only can the dynamic friction torque be measured, but also the multi-point static friction torque can be automatically measured, more comprehensive bearing friction characteristic data are provided, and optimization of bearing design and model selection is facilitated.

Description

Technical Field

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

[0002] In the field of mechanical engineering, bearings are essential components in many machines, and their performance directly impacts the efficiency and service life of the entire equipment. Accurately measuring dynamic and static friction torque is particularly important for medium and large bearings, as these parameters directly reflect the bearing's friction characteristics, which in turn impact the equipment's energy consumption, noise, and reliability.

[0003] Currently, bearing friction torque measurement primarily relies on transfer measurement (using a torque sensor as the transfer element) and balance measurement (calculating friction torque from the balance torque). However, existing technologies suffer from the following deficiencies: Insufficient accuracy: Traditional devices (such as hanging weights and manual measurement with a micrometer) are inefficient and subject to human interference, making high-precision dynamic measurement difficult; 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 require step-by-step measurement of dynamic and static torques, lacking integrated measurement capabilities and resulting in long measurement cycles; and a low degree of automation: They rely on manual adjustment of load, speed, and data recording, preventing real-time feedback control.

[0004] Due to their large size and high loads, medium and large bearings place extremely high demands on the rigidity, stability, and sensitivity of the measuring device. Existing equipment is prone to vibration errors at high rotation speeds and has difficulty simulating the friction torque characteristics under real-world operating conditions.

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

[0006] The object of the present invention is to provide an automatic measurement device and method for the dynamic and static friction torque of medium and large bearings, so as to solve the problems raised in the above background technology.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] Compared with the prior art, the present invention provides an automatic measurement device for the dynamic and static friction torque of medium and large bearings, which includes a control box, a bearing assembly arranged on the top of the control box, and a control unit arranged on one side of the control box. The bearing assembly is provided with a movable plate that can move up and down, and the bottom of the bearing assembly is connected to a rotating motor through a lower fixed frame. The output shaft of the rotating motor is provided with a drive shaft system, and the force sensor is used to measure the actual loading load of the measured bearing. The top of the drive shaft system is provided with an inner ring fixing core shaft for fixing the inner ring of the bearing, and a force sensor is provided on the inner ring fixing core shaft. The upper surface is connected to a torque sensor through an upper fixed frame, and the torque sensor is used to obtain the average dynamic torque, torque range and dynamic torque curve of the measured bearing during one rotation. The bottom end of the torque sensor is provided with a measuring shaft system, and the measuring shaft system is a high-precision air bearing. The bottom end of the measuring shaft system extends to the bottom of the movable plate and is sleeved with a centering component that can reduce interference and ensure measurement accuracy through two guide columns. The bottom of the centering component is provided with an outer ring loading tooling, and the outer ring loading tooling 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 to be measured can be measured.

[0009] Furthermore, the bearing assembly includes a granite workbench, the upper surface of the granite workbench is connected to a top plate via four frames, and the movable plate is socketed with the four frames.

[0010] Furthermore, a loading cylinder is arranged between the centering assembly and the measuring axis system, the centering assembly includes a first ball socket outer ring, a centering disk is arranged on the lower surface of the first ball socket outer ring, a second ball socket outer ring is arranged below the centering disk, an inner socket ball is arranged between the second ball socket outer ring and the centering disk, and the first ball socket outer ring and the second ball socket outer ring are connected by bolts.

[0011] Furthermore, a lifting motor is provided on one side of the top of the bearing assembly, and the lifting motor controls the movement of the movable plate by driving the ball screw.

[0012] Furthermore, the outer ring loading tooling includes a loading seat, the lower surface of the loading seat is slidably connected to three loading bars through three through-slots, the lower surface of the loading bar is slidably connected to a loading block through a slot, 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 spiral rack is provided on the lower surface of the turntable, a tooth groove corresponding to the rack is provided on one side of the top of the loading bar, and a gear 1 is provided on the upper surface of the turntable, and gear 2 is meshedly connected to the gear 1, and an adjustment arm is provided on the gear 2, and the top of the adjustment arm extends out of the loading seat.

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

[0015] Make preliminary adjustments to the outer ring loading fixture according to the size of the bearing to be tested;

[0016] Place the bearing to be tested on the inner ring fixed mandrel, then control the movable plate to move downward 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 the test, the dynamic torque measurement of the bearing or the multi-point static friction torque measurement is 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 to be tested is then converted into an electrical signal, which is then amplified and filtered and sent to the control unit for calculation by the measurement software.

[0018] The control unit displays the calculated data, and the display content includes dynamic measurement results, measurement curves and qualification judgments.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] By adopting the measuring shaft system of air bearing, torque sensor and force sensor, 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] It is suitable for medium and large bearings of various specifications, and can adapt to bearings of different sizes through adjustable outer ring loading fixtures;

[0022] It can not only measure dynamic friction torque, but also automatically measure multi-point static friction torque, giving the static torque distribution of the bearing within one week, providing more comprehensive bearing friction characteristic data, which helps to optimize bearing design and selection. The easy operation and automated design make it simple and easy to operate, without the need for complicated operating steps, reducing the technical requirements for operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

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

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

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

[0027] Figure 4 It is a structural schematic diagram of the bearing assembly of the present invention;

[0028] Figure 5 This is a structural breakdown diagram of the measuring shaft system of the present invention;

[0029] Figure 6 This is a structural breakdown diagram of the rotating electrical machine of the present invention;

[0030] Figure 7 This is a schematic structural diagram of the inner ring fixing core shaft of the present invention;

[0031] Figure 8 This is a structural breakdown diagram of the outer ring loading tooling of the present invention;

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

[0033] In the figure: 1. Granite workbench; 2. Frame; 3. Top plate; 4. Moving plate; 5. Lifting motor; 6. Ball screw; 7. Lower fixed frame; 8. Rotating motor; 9. Driving shaft system; 10. Force sensor; 11. Inner ring fixed core shaft; 12. Upper fixed frame; 13. Torque sensor; 14. Measuring shaft system; 15. Loading cylinder; 16. First ball socket outer ring; 17. Guide column; 18. Second ball socket outer ring; 19. Centering disk; 20. Inner socket ball; 21. Outer ring loading fixture; 2101. Loading seat; 2102. Through slide; 2103. Loading bar; 2104. Slide; 2105. Loading block; 2106. Turntable; 2107. Rack; 2108. Gear 1; 2109. Gear 2; 2110. Adjusting arm; 22. Control box; 23. Control unit. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] See also Figures 1-9 , the present invention provides a technical solution:

[0036] like Figure 1-Figure 3 、 Figure 5 and Figure 6 As shown, an automatic measuring device for the dynamic and static friction torque of medium and large bearings includes a control box 22, a bearing assembly arranged on the top of the control box 22, and a control unit 23 arranged on one side of the control box 22. The bearing assembly provides a platform for installation and operation of other components. A movable plate 4 that can move up and down is provided on the bearing assembly. The bottom of the bearing assembly is connected to a rotating motor 8 through a lower fixed frame 7. The output shaft of the rotating motor 8 is provided with a drive shaft system 9. The top of the drive shaft system 9 is provided with an inner ring fixing core shaft 11 for fixing the inner ring of the bearing. A force sensor 10 is provided on the inner ring fixing core shaft 11. The force sensor 10 is used to accurately measure the load actually loaded on the measured bearing and provide key load data for subsequent measurement data analysis. The upper surface of the movable plate 4 is connected to the upper fixed frame 12 through the upper fixed frame There is a torque sensor 13, which is a key component for measuring the dynamic and static friction torque of the bearing. It can accurately measure the average dynamic torque, torque range and dynamic torque curve of the measured bearing during one rotation, and provide comprehensive data support for evaluating the dynamic friction performance of the bearing. The bottom end of the torque sensor 13 is provided with a measuring shaft system 14, which is an air bearing. The air bearing has the advantages of small friction coefficient, high precision and good stability. It can effectively reduce the reference friction and measurement error and significantly improve the measurement accuracy. The bottom end of the measuring shaft system 14 extends to the bottom of the movable plate 4 and is connected with a centering component through two guide columns 17. The bottom of the centering component is provided with an outer ring loading tooling 21. The centering component can be centered 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 friction torque of a bearing, the measurement of the friction torque includes the measurement of the dynamic friction torque and the measurement of the static friction torque:

[0038] When measuring the dynamic friction torque, the rotating 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 tool 21 to contact the outer ring of the bearing under test, applying a specified load to the bearing under test. The torque sensor 13 measures the average dynamic torque, torque range, and dynamic torque curve of the bearing under test during one rotation.

[0039] When measuring static friction torque, set the number of measurement points within a week, gradually apply load from small to large at the specified angular position, drive the bearing to rotate, measure the maximum torque peak, and average the torque peaks at each measurement point within a week to obtain the static friction torque of the measured bearing and the static torque distribution curve within a week.

[0040] Furthermore, a lifting motor 5 is provided on one side of the top of the bearing assembly. The lifting motor 5 drives the ball screw 6 to control the movement of the movable plate 4. This driving method has the characteristics of high precision and good stability, and can ensure that the movable plate 4 can accurately adjust its position under different measurement conditions.

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

[0042] The instrument uses a computer to control the entire measurement process. The computer first outputs through the I / O and controls the motor circuit to drive the mechanical mechanism to rotate and measure the friction torque signal. All signals are processed and input into the computer through A / D. The computer obtains the friction torque value of the bearing through data processing.

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

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

[0045] b) Measuring range: 0.2Nm;

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

[0047] d) Speed: 1-10 rpm, the forward and reverse rotation error is not greater than ±1% of the full scale;

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

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

[0050] g) Measurement model (8 sets of tooling): 11 types including JMC001 in the table require 8 sets of tooling (select one set of bearings in good condition based on the product conditions, and Party B will provide a calibration certificate)

[0051]

[0052] Conditions of use:

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

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

[0055] In another embodiment, the bearing starting friction torque detector - a large torque measuring device, inner diameter 80-500mm, technical indicators:

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

[0057] b) Measuring range: 2N.m; 10N.m; 100N.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 is 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): 6 types including JMC012 in the table require 6 sets of tooling (select one set of bearings in good condition according to the product conditions, and Party B will provide the calibration certificate)

[0062]

[0063] like Figure 3 As shown, the bearing assembly includes a granite workbench 1 , the upper surface of the granite workbench 1 is connected to a top plate 3 through four frames 2 , and a movable plate 4 is sleeved with the four frames 2 .

[0064] like Figure 4 As shown, a loading cylinder 15 is arranged between the centering assembly and the measuring shaft system 14, and the centering assembly includes a first ball socket outer ring 16, a centering disk 19 is arranged on the lower surface of the first ball socket outer ring 16, a second ball socket outer ring 18 is arranged below the centering disk 19, an inner socket ball 20 is arranged between the second ball socket outer ring 18 and the centering 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, and the lower surface of the loading seat 2101 is slidably connected to three loading bars 2103 through three through-slots 2102, and the lower surface of the loading bar 2103 is slidably connected to a loading block 2105 through a slot 2104, and the loading block 2105 is provided with a screw for limiting the movement of the loading block 2105, and a turntable 2106 is rotatably connected in the loading seat 2101, and a spiral rack 2107 is provided on the lower surface of the turntable 2106, and a tooth groove corresponding to the rack 2107 is opened on one side of the top of the loading bar 2103, and a gear 2108 is provided on the upper surface of the turntable 2106. 08 is internally meshed with gear 2109, and an adjusting arm 2110 is provided on gear 2109. The top of the adjusting arm 2110 extends out of the loading seat 2101. Specifically, when the extrusion cover 1115 is separated from the lower surface of the outer ring loading tooling 21, the adjusting arm 2110 can be rotated to drive gear 2109 to rotate, and then gear 1 2108 drives the turntable 2106 to rotate. The rack 2107 on the turntable 2106 cooperates with the teeth 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, and can be adjusted according to the size and measurement requirements of different bearings.

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

[0067] Perform preliminary adjustments to the outer ring loading fixture 21 based on the size of the bearing to be tested;

[0068] Place the bearing to be tested on the inner ring fixed core shaft 11, then control the movable plate 4 to move downward 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 the test, the dynamic torque measurement of the bearing or the multi-point static friction torque measurement is selected on the measurement software as needed to control the operation of the rotating motor 8. Due to the existence of the internal friction torque of the bearing and the low-friction shaft system of the measurement shaft system, this additional torque can be relatively ignored. The friction torque of the bearing is used as the load torque. The friction torque is transmitted to the torque sensor and the force sensor through the measurement shaft system. The friction torque of the bearing to be tested is then converted into an electrical signal, which is amplified and filtered and then sent to the control unit 23 for calculation by the measurement software.

[0070] The control unit 23 displays the calculated data, and the display content includes dynamic measurement results, measurement curves and qualification judgments.

[0071] Specifically, when the measurement software calculates the electrical signal after amplification and filtering, the specific calculation formula includes:

[0072] When measuring dynamic bearing torque, dynamic friction torque refers to the total frictional resistance torque generated by the rolling elements, cage, lubricant, and seals during the bearing's rotation. Its calculation is usually based on empirical formulas or industry standards. Specific formulas include:

[0073] M=M0+M1+M2

[0074] Among them, M0 is the friction component that is independent of the load and is mainly caused by the viscous resistance of the lubricant;

[0075]

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

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

[0078] n is the rotation speed, in r / min;

[0079] d m is the bearing pitch diameter, in mm;

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

[0081] M1=f1·P1·d m

[0082] f1 is the load friction coefficient, usually 0.0001-0.0005;

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

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

[0085] Specifically, dynamic friction mainly comes from:

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

[0087] Lubricant shear resistance: the shear flow of viscous fluid in the gap, that is, viscous friction.

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

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

[0090] When measuring multi-point static friction torque, the static multi-point friction torque refers to the total friction resistance torque generated by multiple rolling elements simultaneously bearing loads (such as radial load distribution) when the bearing is stationary or at very low speed. It is common in heavy load or preload conditions. The specific formula includes:

[0091] Simplified formula under Hertz contact theory

[0092]

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

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

[0095] d m is the bearing pitch diameter, in m.

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

[0097] Specifically, the principles of multi-point static friction torque measurement include:

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

[0099] Sliding friction: Friction is caused by tiny sliding movements between the rolling elements and the raceways.

[0100] Effect of preload: Preloading the bearing will increase the contact angle, change the load distribution and friction torque.

[0101] When conducting tests, dynamic friction needs to take into account the impact of temperature rise on lubrication 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 working process of this embodiment is as follows: first, according to the size of the bearing to be tested, the inner ring fixing core shaft 11 is adjusted to adapt to the size of the inner ring of the bearing, and then the inner ring of the bearing is placed on the inner ring fixing core shaft 11, and the lifting motor 5 is started to drive the movable plate 4 to descend through the ball screw 6, so that the outer ring loading fixture 21 moves downward, and by rotating the adjusting arm 2110, the gear 2 2109 can be driven to rotate, and then the gear 1 2108 drives the turntable 2106 to rotate, and 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, starting the loading cylinder 15, applying a certain pressure to the outer ring loading fixture 21, so that the bearing is in a loaded state, and starting the rotating motor 2110. Machine 8, drive shaft system 9 drives the inner ring of the bearing to rotate. During the rotation process, the force sensor 10 measures the actual loading load, and the torque sensor 13 measures the average dynamic torque, torque range and dynamic torque curve when the bearing rotates within one circle. The measuring shaft system 14 adopts an air bearing, which effectively reduces friction and measurement errors and improves measurement accuracy. When it is necessary to measure the static friction torque, stop the rotating motor 8, and automatically measure the multi-point static friction torque through the control circuit and signal processing circuit, and record the static torque distribution within one circle of the bearing. After the measurement is completed, release the pressure on the outer ring loading tooling 21, and then start the lifting motor 5 to make the movable plate 4 rise, separate the outer ring loading tooling 21 from the outer ring of the bearing, and finally, release the inner ring fixing core shaft 11 and take out the bearing to be measured.

[0103] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention 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: It includes a control box, a bearing assembly arranged on the top of the control box, and a control unit arranged on one side of the control box, the bearing assembly is provided with a movable plate that can move up and down, the bottom of the bearing assembly is connected to a rotating motor through a lower fixed frame, the output shaft of the rotating motor is provided with a drive shaft system, the force sensor is used to measure the actual load on the tested bearing, the top of the drive shaft system is provided with an inner ring fixing core shaft for fixing the inner ring of the bearing, the inner ring fixing core shaft is provided with a force sensor, the upper surface of the movable plate is connected to a torque sensor through an upper fixed frame, The torque sensor is used to obtain the average dynamic torque, torque range and dynamic torque curve of the measured bearing during one rotation. The bottom end of the torque sensor is provided with a measuring shaft system, which is a high-precision air bearing. The bottom end of the measuring shaft system extends to the bottom of the movable plate and is connected to a centering component through two guide columns to reduce interference and ensure measurement accuracy. The bottom of the centering component is provided with an outer ring loading tooling, 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 to be measured can be measured.

2. The automatic measuring device for dynamic and static friction torque of medium and large bearings according to claim 1, characterized in that: The bearing assembly comprises a granite workbench, the upper surface of the granite workbench is connected with a top plate via four frames, and the movable plate is sleeved 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 loading cylinder is arranged between the centering assembly and the measuring shaft system. The centering assembly includes a first ball socket outer ring, a centering disk is arranged on the lower surface of the first ball socket outer ring, a second ball socket outer ring is arranged below the centering disk, an inner socket ball is arranged between the second ball socket outer ring and the centering disk, and the first ball socket outer ring and the second ball socket outer ring are connected by bolts.

4. 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 assembly, and the lifting motor controls the movement of the moving plate by driving the ball screw.

5. The automatic measuring device for dynamic and static friction torque of medium and large bearings according to claim 1, characterized in that: The outer ring loading tooling includes a loading seat, the lower surface of the loading seat is slidably connected to three loading bars through three through-slots, the lower surface of the loading bars is slidably connected to a loading block through a slot, and the loading block is provided with a screw for limiting the movement of the loading block.

6. The automatic measuring device for dynamic and static friction torque of medium and large bearings according to claim 5, characterized in that: A turntable is rotatably connected inside the loading seat, a spiral rack is provided on the lower surface of the turntable, a tooth groove corresponding to the rack is provided on one side of the top of the loading bar, a gear 1 is provided on the upper surface of the turntable, and a gear 2 is meshedly connected to the gear 1, an adjusting arm is provided on the gear 2, and the top of the adjusting arm extends out of the loading seat.

7. A measurement method based on the automatic measurement device for dynamic and static friction torque of medium and large bearings according to any one of claims 1 to 6, characterized in that: The specific steps include: Make preliminary adjustments to the outer ring loading fixture according to the size of the bearing to be tested; Place the bearing to be tested on the inner ring fixed mandrel, then control the movable plate to move downward 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 the test, the dynamic torque measurement of the bearing or the multi-point static friction torque measurement is 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 to be tested is then converted into an electrical signal, which is then amplified and filtered and sent to the control unit for calculation by the measurement software. The control unit displays the calculated data, and the display content includes dynamic measurement results, measurement curves and qualification judgments.

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