A material friction and wear testing machine system tangential stiffness testing method and device

Abstract

The present invention discloses a method and device for testing the tangential stiffness of a material friction and wear testing machine system. The method comprises a base, a lifting mechanism, a connecting plate, a micro-electric cylinder, a grating support rod, a loading rod, a frame mounted on the base, a normal load loading mechanism, and a laser interferometer. The lifting mechanism is mounted on the frame, the connecting plate is mounted on the lifting mechanism, and the micro-electric cylinder and grating support rod are both mounted on the connecting plate. The loading rod is connected to the micro-electric cylinder, which drives the loading rod to perform horizontal reciprocating motion. The loading rod is provided with a lower fixture and a grating fixture, and the grating support rod is provided with a grating displacement sensor located above the grating fixture. The normal load loading mechanism is provided with an upper fixture located directly above the lower fixture. The testing device and method provided by the present invention can test the tangential static and dynamic stiffness of a friction and wear testing machine system, and has high testing efficiency and accuracy.

Description

Technical Field

[0001] The invention relates to a tangential stiffness testing method and a device for a material friction and wear testing machine system, and belongs to the research field related to mechanical technology. Background Art

[0002] A tribometer is an instrument used to test the friction and wear properties of materials and lubricants under given conditions. Based on their motion, tribometers can be categorized into various types, including reciprocating and fretting. Research on their tangential stiffness has been a focus of considerable research.

[0003] To date, domestic and international scholars' research on fretting wear has focused on the effects of displacement amplitude, load, and frequency on fretting wear behavior. There has been little research on the impact of system stiffness on fretting wear test results. There is still no unified testing method for friction and wear testing machine system stiffness, and no relevant technical standard documents have been formed. There is also little research on friction and wear testing machine system stiffness at home and abroad. In response to the above situation, innovative research and application of tangential stiffness testing methods are needed. The development of a set of tangential stiffness testing methods and equipment suitable for material friction and wear testing machine systems is of great significance to the academic community. Summary of the Invention

[0004] In order to overcome the defects in the prior art, the present invention aims to provide a method and device for testing the tangential stiffness of a material friction and wear testing machine system.

[0005] The present invention solves the above technical problems and provides a technical solution: a tangential stiffness testing device for a material friction and wear testing machine system, comprising a base, a lifting mechanism, a connecting plate, a micro electric cylinder, a grating support rod, a loading rod, a frame mounted on the base, a normal load loading mechanism, and a laser interferometer;

[0006] The lifting mechanism is installed on the frame, the connecting plate is installed on the lifting mechanism, and the micro electric cylinder and the grating support rod are both installed on the connecting plate;

[0007] The loading rod is connected to the micro electric cylinder, and the micro electric cylinder drives the loading rod to perform horizontal reciprocating motion;

[0008] The loading rod is provided with a lower fixture and a grating fixture, and the grating support rod is provided with a grating displacement sensor located above the grating fixture for monitoring the deformation of the loading rod;

[0009] The normal load loading mechanism is provided with an upper fixture located directly above the lower fixture, and the laser interferometer measures the deformation of the normal load loading mechanism.

[0010] A further technical solution is that the grating fixture is provided with a plurality of strip-shaped holes.

[0011] A further technical solution is that a force sensor is provided between the loading rod and the micro electric cylinder.

[0012] A further technical solution is that a vertical lifting mechanism is provided between the base and the laser interferometer, and the vertical lifting mechanism drives the laser interferometer to perform up and down reciprocating motion.

[0013] A method for testing the tangential dynamic stiffness of a material friction and wear testing machine system comprises the following steps:

[0014] Step A, rigidly connecting the loading rod of the test calibration device to the normal loading end of the normal load loading mechanism;

[0015] Step B: Install the grinding pair and the sample on the upper fixture and the lower fixture respectively, adjust the appropriate position so that they are in contact, and adjust the position of the laser interferometer so that it can measure the deformation of the normal load loading mechanism;

[0016] Step C: Increase the normal load point by point according to the process, carry out the i-th test in sequence, and measure the friction force F between the grinding pair and the sample in real time during the test. n ; At the same time, a laser interferometer is used to measure the overall deformation △d of the normal load loading mechanism in real time;

[0017] Step D: Obtain the maximum value F of the friction force readings in the i-th test in sequence max and the maximum deformation value △d measured by the laser interferometer in the i-th test max ; Linear fitting is performed on the friction force and system deformation under different normal loads to obtain the fitting formula F t =K△d+m, the coefficient K is the tangential system stiffness value of the testing machine.

[0018] A further technical solution is that the friction pair is ultrasonically cleaned to remove oil and then dried before use.

[0019] A further technical solution is that the sample is rectangular and has a flat surface, no cracks, stratification, obvious impurities and processing damage; its height is not less than 10 times the contact radius, and the shortest distance between the test position and the edge of the sample is not less than 10 times the contact radius.

[0020] A further technical solution is that in step B, the grinding pair is mounted on the normal load loading mechanism through the upper fixture, and the sample is mounted on the loading rod through the lower fixture; and the device is adjusted so that they are in the same plane and in contact.

[0021] A method for testing the tangential static stiffness of a material friction and wear testing machine system comprises the following steps:

[0022] Step A, rigidly connecting the loading rod of the test calibration device to the normal loading end of the normal load loading mechanism;

[0023] Step B: Increase the tangential thrust point by point according to the process, carry out the i-th test in sequence, and record the tangential thrust F in real time during the test. i At the same time, a grating displacement sensor is used to measure the overall deformation △d of the normal load loading mechanism in real time;

[0024] Step C: Obtain the tangential thrust value F in the i-th test in sequence i , and record the corresponding normal load loading mechanism deformation △d i ; Perform linear fitting on the system deformation under different tangential thrusts to obtain a linear equation. The coefficient in the linear equation is the static stiffness value of the tangential system of the testing machine.

[0025] The present invention has the following beneficial effects:

[0026] 1. The present invention provides driving force through the electric cylinder, which facilitates the rapid movement of the loading rod, thereby realizing the reciprocating motion of the loading rod and achieving precise control;

[0027] 2. The present invention can quickly measure the friction between the grinding pair and the specimen and the overall deformation of the normal loading mechanism by arranging a force sensor and a grating displacement sensor, and can reduce the error caused by the environment, thereby ensuring the efficiency, accuracy and reliability of the measurement data;

[0028] 3. The present invention combines automatic control with non-contact optical measurement technology to achieve rapid detection of system tangential stiffness and improve detection efficiency and accuracy;

[0029] 4. The measuring device of the present invention has the advantages of small size, light weight and portability, which solves the problem that the friction and wear testing machine has stiffness problems but cannot be detected, and fills the research gap in this sector and field. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a perspective view of the device of the present invention;

[0031] Figure 2 A three-dimensional diagram of the device of the present invention from another direction

[0032] Figure 3 It is a right side view of the device of the present invention;

[0033] Figure 4 It is a front view of the device of the present invention;

[0034] Figure 5 A top view of the device of the present invention;

[0035] Figure 6 Schematic diagram of a method for testing the tangential static stiffness of a friction and wear testing machine system.

[0036] Figure 7 Schematic diagram of a method for testing the tangential dynamic stiffness of a friction and wear testing machine system.

[0037] Figure 8 This is a linear fitting diagram of the tangential stiffness of a friction and wear testing machine system.

[0038] As shown in the figure: 1-base; 2-frame; 3-force sensor; 4-grating support rod; 5-lower clamp; 6-normal load loading mechanism; 7-loading rod; 8-laser interferometer; 9-vertical lifting mechanism; 10-connecting plate; 11-grating displacement sensor; 12-grating clamp; 13-micro electric cylinder; 14-lifting mechanism. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] like Figure 1-5 As shown, a tangential stiffness testing device for a material friction and wear testing machine system of the present invention comprises a base 1, a lifting mechanism 14, a connecting plate 10, a micro electric cylinder 13, a grating support rod 4, a loading rod 7, a frame 2 mounted on the base 1, a normal load loading mechanism 6, and a laser interferometer 8;

[0041] The lifting mechanism 14 is mounted on the frame 2 , the connecting plate 10 is mounted on the lifting mechanism 14 , and the micro electric cylinder 13 and the grating support rod 4 are both mounted on the connecting plate 10 ;

[0042] The loading rod 7 is connected to the micro electric cylinder 13, and the micro electric cylinder 13 drives the loading rod 7 to perform horizontal reciprocating motion;

[0043] The loading rod 7 is provided with a lower fixture 5 and a grating fixture 12, and the grating support rod 4 is provided with a grating displacement sensor 11 located just above the grating fixture 12 for monitoring the deformation of the loading rod 4;

[0044] The normal load loading mechanism 6 is provided with an upper fixture located directly above the lower fixture 5 , and the laser interferometer is located to measure the deformation of the normal load loading mechanism 6 .

[0045] The lifting mechanism 14 ensures that the normal load loading mechanism 6 at different heights can be tested, and its height can be adjusted by adjusting the knob; the grating fixture 12 enables the grating to be accurately measured.

[0046] In this embodiment, the lifting mechanism 14 can utilize a motor-driven screw module. This design not only improves the stability and reliability of the system but also ensures precise positioning during lifting. This solution significantly reduces errors during manual operation, allowing the device to maintain a high degree of accuracy and consistency when performing complex tasks. The motor-driven screw module has a good load-bearing capacity, can adapt to the needs of different working conditions, and provides a smooth lifting process.

[0047] The laser interferometer 8 must possess high measurement accuracy, a requirement crucial for measuring normal mechanism deformation. A high-precision laser interferometer 8 is capable of measuring at the micron level, ensuring a sensitive response to minute displacements and significantly improving measurement reliability. Furthermore, the instrument's measurement range must cover small displacements to ensure accurate deformation measurement, enabling it to excel in a variety of applications, particularly those requiring highly sensitive monitoring.

[0048] like Figure 2 As shown, in a preferred embodiment of this invention, the grating fixture 12 is provided with a plurality of strip-shaped holes. This provides flexibility and adjustability for grating installation. The provision of the strip-shaped holes allows for fine adjustments to the grating during installation, optimizing its positioning and calibration, ensuring optimal performance of the optical measurement system. This not only improves the adaptability of the grating but also simplifies maintenance and adjustment.

[0049] like Figure 1 As shown, a preferred embodiment of this invention is to install a force sensor 3 between the loading rod 7 and the micro-electric cylinder 13. This force sensor 3 enables real-time monitoring and feedback control of the pressure exerted by the micro-electric cylinder 13 on the loading rod 7. It accurately measures the applied force and feeds this data back to the control system, enabling dynamic adjustment and ensuring stability and safety during the loading process. This monitoring mechanism promptly detects abnormalities and takes appropriate measures to prevent equipment failure due to overload or uneven force application, thereby improving the efficiency and safety of the entire system.

[0050] like Figure 1As shown, a preferred implementation in this embodiment is that a vertical lifting mechanism 9 is provided between the base 1 and the laser interferometer 8, and the vertical lifting mechanism 9 drives the laser interferometer 8 to reciprocate up and down. In this way, the height of the laser interferometer 8 is adjusted by the vertical lifting mechanism 9, so that it can accurately measure the deformation of the normal load loading mechanism 6.

[0051] The dynamic stiffness test is carried out on the basis of the device, which specifically includes the following steps:

[0052] Step A, rigidly connecting the loading rod of the test calibration device to the normal loading end of the normal load loading mechanism;

[0053] Step B: Mount the grinding pair and the sample on the upper fixture and the lower fixture 5 respectively, adjust the appropriate positions so that they are in contact, and adjust the position of the laser interferometer 8 so that it can measure the deformation of the normal load loading mechanism;

[0054] Step C: Increase the normal load point by point according to the process, carry out the i-th test in sequence, and measure the friction force F between the grinding pair and the sample in real time during the test. n ; At the same time, a laser interferometer is used to measure the overall deformation △d of the normal load loading mechanism in real time;

[0055] Step D: Obtain the maximum value F of the friction force readings in the i-th test in sequence max and the maximum deformation value △d measured by the laser interferometer in the i-th test max ; Linear fitting is performed on the friction force and system deformation under different normal loads to obtain the fitting formula F t =K△d+m, the coefficient K is the tangential system stiffness value of the testing machine.

[0056] In the test method, the friction pair is ultrasonically cleaned to remove oil and dried before use. The specimen is rectangular, with a flat surface and no cracks, delamination, obvious impurities, or processing damage. Its height is no less than 10 times the contact radius, and the shortest distance from the test point to the specimen edge is no less than 10 times the contact radius. If multiple tests are conducted on the same specimen surface, the distance between the centers of adjacent contact areas should be at least 10 times the maximum contact radius. Specimens should be prepared according to ISO 27831-1 before testing.

[0057] In the test method, in step B, the grinding pair is mounted on the normal load loading mechanism through the upper fixture, and the sample is mounted on the loading rod through the lower fixture; and the device is adjusted so that they are in the same plane and in contact.

[0058] In the test method, the obtained data is screened and eliminated to remove points with large errors; the obtained valid data is imported into Matlab and linear fitting is performed to obtain the required system stiffness value.

[0059] The static stiffness test is carried out on the basis of the device, which specifically includes the following steps:

[0060] Step A, rigidly connecting the loading rod of the test calibration device to the normal loading end of the normal load loading mechanism;

[0061] Step B: Increase the tangential thrust point by point according to the process, carry out the i-th test in sequence, and record the tangential thrust F in real time during the test. i At the same time, a grating displacement sensor is used to measure the overall deformation △d of the normal load loading mechanism in real time;

[0062] Step C: Obtain the tangential thrust value F in the i-th test in sequence i , and record the corresponding normal load loading mechanism deformation △d i ; Perform linear fitting on the system deformation under different tangential thrusts to obtain a linear equation. The coefficient in the linear equation is the static stiffness value of the tangential system of the testing machine.

[0063] In summary, the testing device and testing method provided by the present invention can realize the testing of the tangential static stiffness and dynamic stiffness of the friction and wear testing machine system, and have high testing efficiency and testing accuracy.

[0064] The above description does not limit the present invention in any form. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any technician familiar with the profession can use the technical content disclosed above to make some changes or modifications to equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A tangential stiffness testing device for a material friction and wear testing machine system, characterized in that: It includes a base, a lifting mechanism, a connecting plate, a micro electric cylinder, a grating support rod, a loading rod, a frame mounted on the base, a normal load loading mechanism, and a laser interferometer; The lifting mechanism is installed on the frame, the connecting plate is installed on the lifting mechanism, and the micro electric cylinder and the grating support rod are both installed on the connecting plate; The loading rod is connected to the micro electric cylinder, and the micro electric cylinder drives the loading rod to perform horizontal reciprocating motion; The loading rod is provided with a lower fixture and a grating fixture, and the grating support rod is provided with a grating displacement sensor located above the grating fixture for monitoring the deformation of the loading rod; The normal load loading mechanism is provided with an upper clamp located directly above the lower clamp, the laser interferometer measures the deformation of the normal load loading mechanism, the grating clamp is provided with a plurality of strip holes, a force sensor is provided between the loading rod and the micro electric cylinder, and a vertical lifting mechanism is provided between the base and the laser interferometer, and the vertical lifting mechanism drives the laser interferometer to perform reciprocating motion up and down.

2. A method for testing the tangential dynamic stiffness of a material friction and wear testing machine system, characterized in that: The method uses the tangential stiffness testing device of a material friction and wear testing machine system as described in claim 1 to perform testing, and specifically comprises the following steps: Step A, rigidly connecting the loading rod of the test calibration device to the normal loading end of the normal load loading mechanism; Step B: Install the grinding pair and the sample on the upper fixture and the lower fixture respectively, adjust the appropriate position so that they are in contact, and adjust the position of the laser interferometer so that it can measure the deformation of the normal load loading mechanism; In step B, the grinding pair is mounted on the normal load loading mechanism through the upper fixture, and the sample is mounted on the loading rod through the lower fixture; and the device is adjusted so that they are in the same plane and in contact; Step C: Increase the normal load point by point according to the process, carry out the i-th test in sequence, and measure the friction force F between the grinding pair and the sample in real time during the test. n ; At the same time, a laser interferometer is used to measure the overall deformation △d of the normal load loading mechanism in real time; Step D: Obtain the maximum value F of the friction force readings in the i-th test in sequence max and the maximum deformation value △d measured by the laser interferometer in the i-th test max ; Linear fitting is performed on the friction force and system deformation under different normal loads to obtain the fitting formula F t =K△d+m, the coefficient K is the dynamic stiffness value of the tangential system of the testing machine.

3. The method for testing the tangential dynamic stiffness of a material friction and wear testing machine system according to claim 2, characterized in that: The grinding pair is ultrasonically cleaned to remove oil and then dried before use.

4. The method for testing the tangential dynamic stiffness of a material friction and wear testing machine system according to claim 2, characterized in that: The specimen is rectangular and has a smooth surface without cracks, delamination, obvious impurities and processing damage; Its height shall not be less than 10 times the contact radius, and the shortest distance between the test position and the edge of the sample shall not be less than 10 times the contact radius.

5. A method for testing the tangential static stiffness of a material friction and wear testing machine system, characterized in that: The method uses the tangential stiffness testing device of a material friction and wear testing machine system as described in claim 1 to perform testing, and specifically comprises the following steps: Step A, rigidly connecting the loading rod of the test calibration device to the normal loading end of the normal load loading mechanism; Step B: Increase the tangential thrust point by point according to the process, carry out the i-th test in sequence, and record the tangential thrust F in real time during the test. i At the same time, a grating displacement sensor is used to measure the overall deformation △d of the normal load loading mechanism in real time; Step C: Obtain the tangential thrust value F in the i-th test in sequence i , and record the corresponding normal load loading mechanism deformation △d i ; Perform linear fitting on the system deformation under different tangential thrusts to obtain a linear equation. The coefficient in the linear equation is the static stiffness value of the tangential system of the testing machine.

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