Electric contact high-frequency fretting wear tester and testing method

Abstract

The invention discloses an electric contact high-frequency fretting wear tester and a testing method. The tester comprises a direct-current power supply, an upper sample clamp, a lower sample clamp, a vibration exciter, a spring sleeve, a ball head retainer and a driving mechanism, and an input line of the direct-current power supply is connected with an upper sample and a lower sample respectively; the lower sample clamp is arranged below the upper sample clamp; a sliding shaft is movably mounted on a driving arm of the vibration exciter, and the upper sample clamp is mounted on the sliding shaft; a spring is arranged in the spring sleeve; the ball head retainer is connected with the lower part of the spring, a rolling ball is mounted in the ball head retainer, and the rolling ball is arranged above the sliding shaft; the driving mechanism drives the spring sleeve to move in the vertical direction, and the rolling ball extrudes the sliding shaft under the action of the driving mechanism. The electrical contact high-frequency fretting wear tester can be used for simulating high-frequency vibration behaviors of conductor materials under actual service conditions.

Description

Technical Field

[0001] The present invention relates to the field of tribology, and particularly to an electric contact high-frequency fretting wear tester and a test method thereof. Background Art

[0002] Fretting refers to the extremely small relative displacement movement caused by alternating loads or vibrations between contacting surfaces. This phenomenon widely exists in mechanical structures. Because the relative displacement is tiny, fretting behavior is often ignored in the design stage, but in fact, it can cause significant friction and wear, leading to the degradation of component performance and even functional failure, such as biting, loosening, and even becoming a pollution source. More seriously, fretting wear may promote the formation and expansion of cracks, accelerate component fatigue failure, and significantly shorten its service life. Therefore, the fretting phenomenon has become one of the main factors for component failure in multiple industrial fields. In-depth research on its mechanism and the formulation of effective prevention and control measures are crucial for the reliability and durability of mechanical systems.

[0003] In the power transmission system, the connecting clamp is a key component in the 10 kV distribution network, and its anti-wear performance and service life are particularly important. However, in actual operation, it is found that fretting wear-induced electrical contact failure due to wind-induced vibration accounts for the highest proportion of connecting clamp failures. Fretting wear will significantly increase the contact resistance. If the contact resistance exceeds the critical value, it will cause the interruption of circuit transmission and lead to circuit system failures. According to statistics, 40%-50% of circuit system failure cases are closely related to electrical contact problems, which poses a major challenge to the reliability of electrical systems. Therefore, in-depth research on electrical contact fretting wear and the development of high-precision test equipment for simulating and evaluating its behavior have become important research directions in this field.

[0004] Electrical contact fretting wear is a complex wear phenomenon caused by high-frequency and small-amplitude relative movement between conductive contacts, and its characteristics include contact resistance fluctuation, micro-fatigue damage and surface damage of contact materials. In the prior art, most electrical contact friction test devices can only simulate sliding friction and wear, such as sliding electrical contact devices, or analyze based on simplified contact modes of cylindrical pins and disks, bearings. And the existing devices are difficult to achieve high-frequency fretting loading, resulting in the lack of reference value of test results for actual service conditions. In sliding friction tests, additional friction interference introduced by the guide rail design also affects the accurate measurement of friction force and contact resistance. Therefore, a new electrical contact high-frequency fretting wear tester is needed. Summary of the Invention

[0005] The purpose of the present invention is to provide an electric contact high-frequency fretting wear tester and a test method thereof, which are used to simulate the high-frequency vibration behavior of conductor materials under actual service conditions.

[0006] In one aspect of the present invention, an electrical contact high-frequency fretting wear tester is proposed. According to an embodiment of the present invention, it includes:

[0007] A DC power supply, the input wires of the DC power supply are respectively connected to the upper specimen and the lower specimen;

[0008] An upper specimen fixture and a lower specimen fixture, the lower specimen fixture is arranged below the upper specimen fixture;

[0009] An exciter, a sliding shaft is movably installed on the driving arm of the exciter, and the upper specimen fixture is installed on the sliding shaft;

[0010] A spring sleeve, a spring is arranged inside the spring sleeve;

[0011] A ball head retainer, the ball head retainer is connected to the lower part of the spring, a rolling ball is installed inside the ball head retainer, and the rolling ball is arranged above the sliding shaft;

[0012] A driving mechanism, the driving mechanism drives the spring sleeve to move in the vertical direction, and under the action of the driving mechanism, the rolling ball presses the sliding shaft.

[0013] In addition, the electrical contact high-frequency fretting wear tester according to the above embodiment of the present invention may further have the following additional technical features:

[0014] In some embodiments of the present invention, it further includes an insulating base, and an insulating housing is sleeved outside the insulating base.

[0015] In some embodiments of the present invention, a two-dimensional force sensor is installed at the upper end of the insulating base, and the lower specimen fixture is fixed on the two-dimensional force sensor.

[0016] In some embodiments of the present invention, the exciter is installed on the base through a cage, a fixed seat is arranged on one side of the exciter, and the driving arm of the exciter is connected to the fixed seat through a top linear bearing.

[0017] In some embodiments of the present invention, the sliding shaft is connected to the driving arm of the exciter through a driving arm linear bearing.

[0018] In some embodiments of the present invention, an upper fixing plate is fixed at the upper end of the spring sleeve, a lower fixing plate is arranged inside the spring sleeve, the upper end and the lower end of the spring are respectively fixed to the upper fixing plate and the lower fixing plate, and the lower fixing plate extends out of the spring sleeve and is fixed to the ball head retainer.

[0019] In some embodiments of the present invention, the driving mechanism includes:

[0020] A mounting frame, a guide rail is fixed on the mounting frame;

[0021] A servo motor, the servo motor is connected to one end of a lead screw through a coupling, the other end of the lead screw is connected to a mounting bracket through a bearing, and the lead screw passes through a slider and is threadedly connected to the slider;

[0022] A guide rail, the slider is mounted on the guide rail;

[0023] An elastic compensation adapter plate, the elastic compensation adapter plate is fixed to the slider through a guide rail adapter plate, and a spring sleeve is installed at the lower end of the elastic compensation adapter plate.

[0024] In some embodiments of the present invention, graphite is embedded in the inner wall of the spring sleeve.

[0025] In some embodiments of the present invention, the material of the lower specimen fixture is polytetrafluoroethylene material.

[0026] In another aspect of the present invention, the present invention provides an electric contact high-frequency fretting wear test method. According to an embodiment of the present invention, the test is carried out using the electric contact high-frequency fretting wear tester, and the method includes the following steps:

[0027] (1) Install the specimen

[0028] Fix the upper specimen and the lower specimen on the upper specimen fixture and the lower specimen fixture respectively, and connect the input wires of the current to the upper specimen and the lower specimen respectively;

[0029] (2) Start the detection equipment and software

[0030] Start the DC power supply, the resistance measurement system, and the two-dimensional force sensor detection software;

[0031] (3) Set parameters and start the test

[0032] Set the power supply current parameters, start the drive mechanism and the exciter, then adjust the test parameters, the upper specimen always makes a horizontal reciprocating motion, as the wear deepens, the pressure decreases, the drive mechanism drives the spring sleeve to descend, and continues to press the upper specimen through the rolling ball to keep the pressure stable;

[0033] (4) The test ends

[0034] After the test ends, turn off the exciter and the DC power supply in sequence, save the relevant data, and conduct a resistance comparison and morphology analysis on the friction pair specimen.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1) The present invention utilizes an exciter to simulate the reciprocating high-frequency fretting wear service behavior that occurs at the contact interface of conductive contacts during actual service. By combining the exciter with servo motor drive technology, the normal pressure and vibration amplitude can be precisely adjusted, and key parameters such as contact resistance, friction coefficient, and normal pressure can be dynamically collected through a two-dimensional force sensor.

[0037] 2) The present invention adopts a linear bearing support structure to ensure motion accuracy, and designs a ball head rolling friction to avoid the interference of traditional guide rail sliding friction on measurement, thereby significantly improving the accuracy and repeatability of measurement. The lateral movement between the upper specimen and the rolling ball replaces the traditional guide rail sliding friction with ball head rolling friction, avoiding the interference of guide rail sliding wear on the measurement of friction force and ensuring the accuracy and repeatability of friction force measurement.

[0038] 3) The present invention uses a servo motor to drive a ball screw to drive a slider to achieve up and down displacement control, thereby adjusting the compression amount of the spring in the spring sleeve and providing precise normal pressure loading for the upper specimen. The spring sleeve design ensures the continuity and stability of the loading force, and at the same time has a displacement compensation function, which can effectively avoid test errors caused by the rigid impact of the servo motor.

[0039] 4) The present invention can collect multi-dimensional data such as contact resistance, friction coefficient, and pressure in real time, providing a scientific basis for optimizing the performance of conductive contacts.

[0040] 5) Through the equipment of the present invention, researchers can simulate the high-frequency vibration failure behavior of electrical contacts under real working conditions, systematically analyze its wear mechanism and evolution law, and provide a scientific basis for solving the problem of electrical contact wear and optimizing the performance of conductive contacts. Description of the Drawings

[0041] Figure 1 is a schematic structural diagram of the electrical contact high-frequency fretting wear tester in Embodiment 1 of the present invention;

[0042] Figure 2 is a schematic structural diagram inside the insulating shell of the electrical contact high-frequency fretting wear tester in Embodiment 1 of the present invention;

[0043] Figure 3 is a schematic structural diagram of the drive mechanism in Embodiment 1 of the present invention;

[0044] Figure 4 is a schematic structural diagram inside the spring sleeve in Embodiment 1 of the present invention;

[0045] Figure 5 is a schematic structural diagram at the exciter in Embodiment 1 of the present invention;

[0046] Figure 6 is a schematic structural diagram at the sliding shaft in Embodiment 1 of the present invention;

[0047] In the figure, 1 is a DC power supply, 2 is an upper specimen fixture, 3 is a lower specimen fixture, 4 is a vibrator, 5 is a spring sleeve, 6 is a ball head retainer, 7 is a driving mechanism, 701 is a mounting bracket, 702 is a servo motor, 703 is a guide rail, 704 is an elastic compensation adapter plate, 705 is a machine base, 706 is a coupling, 707 is a ball screw, 708 is a slider, 709 is a guide rail adapter plate, 8 is an insulating base, 9 is an insulating housing, 10 is an opening and closing door, 11 is a handle, 12 is a two-dimensional force sensor, 13 is a lower specimen, 14 is an upper specimen, 15 is a base, 16 is a fixed seat, 17 is a top linear bearing, 18 is a sliding shaft, 19 is a driving arm linear bearing, 20 is a spring, 21 is an upper fixing plate, 22 is a lower fixing plate, 23 is a rolling ball, 24 is a retainer, and 25 is a driving arm. Specific implementation mode

[0048] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] Embodiment 1

[0050] The electric contact high-frequency fretting wear tester includes a DC power supply 1, an upper specimen fixture 2, a lower specimen fixture 3, a vibrator 4, a spring sleeve 5, a ball head retainer 6, a driving mechanism 7, and an insulating base 8. As Figure 1 shown, an insulating housing 9 is sleeved outside the insulating base 8, an opening and closing door 10 is hinged on the insulating housing 9, and a handle 11 is installed on the opening and closing door 10. As Figure 2 shown, a two-dimensional force sensor 12 is installed at the upper end of the insulating base 8, the lower specimen fixture 3 is fixed on the two-dimensional force sensor 12, and a groove for clamping the lower specimen 13 is provided at the upper end of the lower specimen fixture 3. The material of the lower specimen fixture 3 is polytetrafluoroethylene material, and the self-lubricity of polytetrafluoroethylene can further reduce the interference of rolling friction at the rolling ball 23. The lower specimen fixture 3 is arranged below the upper specimen fixture 2, the upper specimen fixture 2 is a U-shaped clamp, and the input wires of the DC power supply 1 are respectively connected to the upper specimen 14 and the lower specimen 13.

[0051] As Figure 5 shown, the vibrator 4 is arranged on one side of the lower specimen fixture 3, a base 15 is installed on the insulating base 8, and the vibrator 4 is installed on the base 15 through a retainer 24. A fixed seat 16 is arranged on the side of the lower specimen fixture 3 away from the vibrator 4, the fixed seat 16 is fixed on the insulating base 8, and the driving arm 25 of the vibrator 4 is connected to the fixed seat 16 through a top linear bearing 17. As Figure 6As shown, a perforation is provided on the driving arm 25 of the vibrator 4. A sliding shaft 18 is provided in the perforation. The sliding shaft 18 and the driving arm 25 are connected through a linear bearing 19 of the driving arm. The U-shaped clamp is fixed by threaded connection with the sliding shaft 18.

[0052] As Figure 4 shown, a spring 20 is arranged inside the spring sleeve 5. An upper fixing plate 21 is fixed at the upper end of the spring sleeve 5. A lower fixing plate 22 is arranged inside the spring sleeve 5. The upper and lower ends of the spring 20 are respectively fixed to the upper fixing plate 21 and the lower fixing plate 22. The lower fixing plate 22 extends out of the spring sleeve 5 and is connected with the ball head retainer 6 through threaded connection. A rolling ball 23 is installed inside the ball head retainer 6. The rolling ball 23 is arranged above the sliding shaft 18. Graphite is embedded on the inner wall of the spring sleeve 5 to play a role of self-lubrication.

[0053] The driving mechanism 7 drives the spring sleeve 5 to move in the vertical direction. Under the action of the driving mechanism 7, the rolling ball 23 presses the sliding shaft 18. Specifically, as Figure 3 shown, the driving mechanism 7 includes a mounting frame 701, a servo motor 702, a guide rail 703, and an elastic compensation adapter plate 704. The mounting frame 701 is fixed on the insulating base 8. The guide rail 703 is fixed on the mounting frame 701. The servo motor 702 is fixed on the mounting frame 701 through a machine base 705. The output shaft of the servo motor 702 is connected to one end of a ball screw 707 through a coupling 706. The other end of the ball screw 707 is connected with the mounting frame 701 through a bearing. The ball screw 707 passes through a slider 708 and is connected with the slider 708 through threaded connection. The slider 708 is installed on the guide rail 703. The elastic compensation adapter plate 704 is fixed with the slider 708 through a guide rail adapter plate 709. The spring sleeve 5 is fixedly installed at the lower end of the elastic compensation adapter plate 704 through the upper fixing plate 21.

[0054] Working principle: The upper specimen 14 and the lower specimen 13 are respectively fixed on the upper specimen clamp 2 and the lower specimen clamp 3. The input wires of the current are respectively connected to the upper specimen 14 and the lower specimen 13. The servo motor 702 drives the coupling 706 to drive the slider 708 on the ball screw 707 to move up and down along the guide rail 703 to apply a normal load. The slider 708 drives the elastic compensation adapter plate 704 through the guide rail adapter plate 709, driving the spring sleeve 5 to move in the vertical direction. The lower fixing plate 22 can slide up and down inside the spring sleeve 5 to achieve force compensation, thereby driving the rolling ball 23 to press the sliding shaft 18, enabling the sliding shaft 18 to move in the vertical direction inside the linear bearing 19 of the driving arm. The vibrator 4 drives the driving arm 25 to perform a reciprocating horizontal movement inside the top linear bearing 17, thereby generating friction between the upper specimen 14 and the lower specimen 13.

[0055] Embodiment 2

[0056] An electric contact high-frequency fretting wear test method includes the following steps:

[0057] (1) Install the specimens

[0058] Fix the upper specimen 14 and the lower specimen 13 on the upper specimen fixture 2 and the lower specimen fixture 3 respectively, and connect the input wires of the current to the upper specimen 14 and the lower specimen 13 respectively;

[0059] (2) Start the detection equipment and software

[0060] Start the detection software of the DC power supply 1 and the two-dimensional force sensor 12;

[0061] (3) Set parameters and start the test

[0062] Set the power current parameters, start the driving mechanism 7 and the exciter 4, adjust the test parameters, and conduct the test;

[0063] When the exciter is turned on, the upper specimen 14 will always perform horizontal reciprocating motion. As the wear deepens, the pressure will decrease. In order to ensure that the pressure remains stable, the ball screw 707 will drive the spring sleeve 5 to descend, and continue to press down the sliding shaft 18 and the upper specimen 14 through the rolling ball 23 to keep the pressure stable.

[0064] Collect the friction force and pressure through the two-dimensional force sensor: Transmit the signals collected by the two-dimensional force sensor to the acquisition card for analysis, and measure the pressure and friction force respectively. Among them, the acquisition card is set in the computer.

[0065] Collect the resistance: Connect two sections of leads to the acquisition card on the upper specimen and the lower specimen respectively, collect the voltage, and calculate the resistance through voltage-current conversion.

[0066] (4) End of the test

[0067] After the test is completed, turn off the exciter 4 and the DC power supply 1 in sequence, save the relevant data, and conduct resistance comparison and morphology analysis on the friction pair specimens.

[0068] The above content is only an example and explanation of the structure and method of the present invention. Those skilled in the art of this technology make various modifications or supplements to the described specific embodiments or use similar methods for substitution. As long as they do not deviate from the structure of the present invention or exceed the scope defined by this claim book, they should all belong to the protection scope of the present invention.

Claims

1. Electric contact high-frequency fretting wear tester, characterized in that, Including: A DC power supply, the input wires of which are respectively connected to the upper specimen and the lower specimen; An upper specimen fixture and a lower specimen fixture, the lower specimen fixture being arranged below the upper specimen fixture; An exciter, on the driving arm of which a sliding shaft is movably installed, and the upper specimen fixture is installed on the sliding shaft; A spring sleeve, in which a spring is arranged; A ball head retainer, which is connected to the lower part of the spring, and in which rolling balls are installed, and the rolling balls are arranged above the sliding shaft; A driving mechanism, which drives the spring sleeve to move in the vertical direction, and under the action of the driving mechanism, the rolling balls press against the sliding shaft.

2. The electric contact high-frequency fretting wear tester according to claim 1, characterized in that: It further includes an insulating base, and an insulating housing is sleeved outside the insulating base.

3. The electrical contact high-frequency fretting wear tester according to claim 2, wherein: A two-dimensional force sensor is installed at the upper end of the insulating base, and the lower specimen fixture is fixed on the two-dimensional force sensor.

4. The electric contact high-frequency micro-motion wear tester according to claim 1, wherein: The exciter is installed on the base through a cage, a fixed seat is arranged on one side of the exciter, and the driving arm of the exciter is connected to the fixed seat through a top linear bearing.

5. The electric contact high-frequency fretting wear tester according to claim 1, characterized in that: The sliding shaft is connected to the driving arm of the exciter through a driving arm linear bearing.

6. The electric contact high-frequency fretting wear tester according to claim 1, wherein: An upper fixing plate is fixed at the upper end of the spring sleeve, a lower fixing plate is arranged in the spring sleeve, the upper and lower ends of the spring are respectively fixed to the upper fixing plate and the lower fixing plate, and the lower fixing plate extends out of the spring sleeve and is fixed to the ball head retainer.

7. The electric contact high-frequency fretting wear tester according to claim 1, characterized in that, The driving mechanism includes: A mounting frame, on which a guide rail is fixed; A servo motor, one end of the lead screw is connected to the servo motor through a coupling, the other end of the lead screw is connected to the mounting frame through a bearing, and the lead screw passes through the slider and is threadedly connected to the slider; A guide rail, on which the slider is installed; An elastic compensation adapter plate, which is fixed to the slider through a guide rail adapter plate, and the spring sleeve is installed at the lower end of the elastic compensation adapter plate.

8. The electric contact high-frequency micro-motion wear tester according to claim 1, characterized in that: Graphite is embedded in the inner wall of the spring sleeve.

9. The electric contact high-frequency micro-motion wear tester according to claim 1, wherein: The material of the lower specimen fixture is polytetrafluoroethylene material.

10. A method for high-frequency micro-motion wear test of electrical contact, characterized in that, Using the electrical contact high-frequency fretting wear tester described in claim 1 for testing, specifically including the following steps: (1) Install the specimens Fix the upper specimen and the lower specimen on the upper specimen fixture and the lower specimen fixture respectively, and connect the input wires of the current to the upper specimen and the lower specimen respectively; (2) Start the detection equipment and software Start the DC power supply, the resistance measurement system, and the two-dimensional force sensor detection software; (3) Set parameters and start the test Set the power supply current parameters, start the driving mechanism and the exciter, the upper specimen always makes horizontal reciprocating movements, as the wear deepens and the pressure decreases, the driving mechanism drives the spring sleeve to descend, and the upper specimen is continuously pressed down through the rolling balls to keep the pressure stable; Adjust the test parameters and conduct the test; (4) End of the test After the test is completed, turn off the exciter and the DC power supply in sequence, save the relevant data, and conduct a resistance comparison and morphology analysis on the friction pair specimens.

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