Method and device for testing tangential rigidity of material friction-wear testing machine system

Abstract

The invention discloses a method and a device for testing tangential rigidity of a material friction-wear testing machine system. The device comprises a base, a lifting mechanism, a connecting plate, a micro electric cylinder, a grating supporting rod, a loading rod, a rack, a normal load loading mechanism and a laser interferometer, wherein the rack, the normal load loading mechanism and the laser interferometer are mounted on the base; the lifting mechanism is installed on the rack, the connecting plate is installed on the lifting mechanism, and the micro electric cylinder and the grating supporting rod are both installed on the connecting plate; the loading rod is connected with the micro electric cylinder, and the micro electric cylinder drives the loading rod to do horizontal reciprocating motion; a lower clamp and a grating clamp are arranged on the loading rod, and a grating displacement sensor located above the grating clamp is arranged on the grating supporting rod; an upper clamp located over the lower clamp is arranged on the normal load loading mechanism. According to the testing device and the testing method provided by the invention, the tangential static stiffness and dynamic stiffness of the friction-wear testing machine system can be tested, and the testing device and the testing method have relatively high testing efficiency and testing precision.

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 friction and wear tester is an instrument for testing the friction and wear performance of materials and lubricants under given conditions. According to the form of motion, friction and wear testers can be divided into reciprocating friction and wear testers, micro-motion wear testers and other types. The study of its tangential stiffness has always been widely concerned.

[0003] So far, domestic and foreign scholars have focused their research on fretting wear on the effects of displacement amplitude, load, and frequency on fretting wear behavior. There is little research on the effects of system stiffness on fretting wear test results. The test methods for friction and wear testing machine system stiffness are still not unified, and relevant technical standard documents have not yet been formed. There are also few studies on friction and wear testing machine system stiffness at home and abroad. In view of the above situation, it is necessary to conduct innovative research and application of tangential stiffness test methods, and develop a set of tangential stiffness test methods and devices suitable for material friction and wear testing machine systems, which 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 technical solution provided by the present invention to solve the above technical problems is: a tangential stiffness test 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 and 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 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, specifically comprising 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, respectively install the grinding pair and the sample on the upper fixture and the lower fixture, adjust the appropriate positions to make them 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 dried before use.

[0019] A further technical solution is that the sample is rectangular and has a flat surface without cracks, delamination, obvious impurities and processing damage; its height is not less than 10 times the contact radius, and the shortest distance from the test position to 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 an upper fixture, and the sample is mounted on the loading rod through a 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, specifically comprising 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, the 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 deformation △d of the normal load loading mechanism i ; Perform linear fitting on the system deformation under different tangential thrusts to obtain a first-order equation, in which the coefficient 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 sample 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 high 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 three-dimensional diagram 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 This is a schematic diagram of a method for testing the tangential static stiffness of a friction and wear testing machine system.

[0036] Figure 7 This is a 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 described clearly and completely below 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 creative work are within the scope of protection of the present invention.

[0040] like Figure 1-5 As shown, a tangential stiffness test device of 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 installed on the frame 2, the connecting plate 10 is installed on the lifting mechanism 14, and the micro electric cylinder 13 and the grating support rod 4 are both installed 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, which is used to monitor 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 use a motor-driven screw module. This design not only improves the stability and reliability of the system, but also ensures that the predetermined position can be accurately reached during lifting. This solution significantly reduces the error in the manual operation process, allowing the equipment to maintain a high degree of accuracy and consistency when performing complex tasks. The motor-driven screw module has good load-bearing capacity, can adapt to the needs of different working conditions, and provide a smooth lifting process.

[0047] The laser interferometer 8 should have high measurement accuracy, which is crucial for measuring the deformation of the normal mechanism. The high-precision laser interferometer 8 can measure at the micron level, ensuring sensitive response to tiny displacements, greatly improving the reliability of the measurement. At the same time, the measurement range of the instrument needs to cover small displacements to ensure the measurement accuracy of the deformation, so that it can perform well in various applications, especially in areas that require high-sensitivity monitoring.

[0048] like Figure 2 As shown, in this embodiment, a preferred implementation is that the grating fixture 12 is provided with a plurality of strip holes. The purpose is to provide flexibility and adjustability for installing the grating. The provision of the strip holes enables the grating to be finely adjusted according to actual conditions during the installation process, thereby optimizing the positioning and calibration of the grating and ensuring that the performance of the optical measurement system reaches the best state. This not only improves the adaptability of the grating, but also simplifies the maintenance and adjustment process.

[0049] like Figure 1 As shown, in this embodiment, a preferred implementation is that a force sensor 3 is provided between the loading rod 7 and the micro-electric cylinder 13. The force sensor 3 makes it possible to monitor and feedback control the pressure of the micro-electric cylinder 13 on the loading rod 7 in real time; it can accurately measure the applied force and feed back the data to the control system, thereby achieving dynamic adjustment and ensuring stability and safety during the loading process. This monitoring mechanism can detect abnormal conditions in a timely manner and take corresponding measures to prevent equipment failure due to overload or uneven force application, thereby improving the working efficiency and safety of the entire system.

[0050] like Figure 1As shown, a preferred implementation manner 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, so that 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, respectively install the grinding pair and the sample on the upper fixture and the lower fixture 5, adjust the appropriate positions to make them 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, no cracks, delamination, 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. If multiple tests are performed on the same sample surface, the distance between the center positions of adjacent contact areas should be greater than 10 times the maximum contact radius. The test piece 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; 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, the 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 deformation △d of the normal load loading mechanism i ; Perform linear fitting on the system deformation under different tangential thrusts to obtain a first-order equation, in which the coefficient 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 is not intended to 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 make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, 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 installed 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 fixture located directly above the lower fixture, and the laser interferometer measures the deformation of the normal load loading mechanism.

2. The tangential stiffness testing device of a material friction and wear testing machine system according to claim 1, characterized in that: The grating fixture is provided with a plurality of strip holes.

3. The tangential stiffness testing device of a material friction and wear testing machine system according to claim 1, characterized in that: A force sensor is provided between the loading rod and the micro electric cylinder.

4. The tangential stiffness testing device of a material friction and wear testing machine system according to claim 1, characterized in 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.

5. A method for testing the tangential dynamic stiffness of a material friction and wear testing machine system, characterized in that: The method adopts a material friction and wear testing machine system tangential stiffness testing device as described in any one of claims 1 to 4 for 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, respectively install the grinding pair and the sample on the upper fixture and the lower fixture, adjust the appropriate positions to make them contact, and adjust the position of the laser interferometer so that it can measure the deformation of the normal load loading mechanism; 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.

6. The method for testing tangential dynamic stiffness of a material friction and wear testing machine system according to claim 5, characterized in that: The friction pair is ultrasonically cleaned to remove oil and then dried before use.

7. The method for testing tangential dynamic stiffness of a material friction and wear testing machine system according to claim 5, characterized in that: The sample is rectangular and has a flat 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.

8. The method for testing tangential dynamic stiffness of a material friction and wear testing machine system according to claim 5, characterized in 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.

9. A method for testing the tangential static stiffness of a material friction and wear testing machine system, characterized in that: The method adopts a material friction and wear testing machine system tangential stiffness testing device as described in any one of claims 1 to 4 for 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, the 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 deformation △d of the normal load loading mechanism i ; Perform linear fitting on the system deformation under different tangential thrusts to obtain a first-order equation, in which the coefficient is the static stiffness value of the tangential system of the testing machine.

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