System and method for measuring self-friction coefficient of wire rod

Abstract

The invention relates to a system and a method for measuring the self-friction coefficient of a wire rod. The method comprises the following steps: tightly winding the wire rod to be measured on a bearing and fixing by a bolt; the bearing is mounted in the groove of the base; respectively clamping and fixing the pulley assembly and the base by using a tensile testing machine; a to-be-tested wire rod is placed between the slide rails of the base, and one end of the to-be-tested wire rod is connected to the force sensor; by adjusting the distance between clamps of the tensile testing machine, the pulley assembly generates an extrusion effect on a wound wire rod, so that the wire rod to be tested on the sliding rail is extruded; the extrusion force is obtained by reading the reading of the tensile testing machine, the friction force between the wires is obtained through the force sensor, and the friction coefficient of the wire to be tested is calculated. According to the invention, the test design of winding and point contact is adopted, and the tensile testing machine and the force sensor are combined, so that the friction coefficient of the wire rod is efficiently and accurately measured. On the premise of maintaining the original morphology and structure of the wire rod, the friction coefficient of the wire rod can be accurately measured, and an important basis is provided for wire rod performance evaluation and optimization.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical surgical instruments, and in particular to a wire self-friction coefficient measurement system and method. Background Art

[0002] Wire is an important material widely used in industrial production, construction engineering, electronic devices and other fields. Its surface friction performance has an important impact on the service life, processing technology and working performance of the wire. In practical applications, the friction coefficient of the wire surface not only determines the stability of the wire during processing such as stretching, bending and extrusion, but also directly affects the friction and wear performance of the wire under dynamic use conditions. Therefore, the accurate measurement of the wire surface friction coefficient is of great significance for optimizing the wire processing technology and improving its performance.

[0003] However, the friction force test of wire is more challenging than that of sheet. This is because the surface contact characteristics of wire are significantly different from those of sheet. The diameter of wire is small and it has a curved structure, and the contact with the test component is mostly point contact or local contact, rather than the surface contact of sheet. This point contact characteristic makes it easy to produce deformation of the contact surface when applying load, resulting in unstable friction force test results. In addition, the friction performance of wire under dynamic loading is greatly affected by the force distribution and contact area. Precise control of the contact state and loading method is required during the test, which further increases the complexity of the test.

[0004] During the process of processing ordinary sheet into wire, due to manufacturing processes such as fiber winding and braiding, the arrangement density, directionality and structural characteristics of the fibers often change. Specifically, the arrangement of the internal fibers of the wire changes from a unidirectional distribution to a more complex cross or spiral structure, and the surface roughness and local contact point density also change accordingly. This structural change makes the surface friction performance of the wire more difficult to predict and puts forward higher requirements for the measurement accuracy of the friction force. Therefore, when evaluating the friction performance of wire, its unique morphology and structural characteristics must be considered to ensure that the test results can truly reflect the friction performance of the wire in actual applications.

[0005] The existing friction coefficient measurement methods mainly include flat-flat friction testing, cylinder-flat friction testing, wheel-rail friction testing, etc. These methods are mainly applicable to the measurement of the friction coefficient between two planar materials. Their testing principles are usually based on the relative sliding of a plane or a simple contact surface, and the friction coefficient is calculated by applying an external force and measuring the frictional force. Such methods have good applicability and measurement accuracy when dealing with materials with flat surfaces and uniform structures. However, for wire materials with curved contact characteristics or complex surface structures, since their contact forms are mostly point contact or local contact, it is difficult for the existing methods to accurately simulate the force conditions and contact behaviors under actual working conditions, resulting in relatively large errors or inaccuracies in the measurement results of the friction coefficient. Therefore, the existing testing methods have obvious limitations when measuring the friction coefficient of wire materials.

[0006] To address the above problems, there is an urgent need in the market for a testing system and method that can accurately measure the friction coefficient of wire materials while maintaining the original morphology and surface structure of the wire materials, in order to meet the needs of various wire material performance evaluations and optimizations. Summary of the Invention

[0007] The object of the present invention is to overcome the deficiencies of the prior art and propose a wire self-friction coefficient measurement system and method. By adopting a test design of winding and point contact, and combining a tensile testing machine and a force sensor, the efficient and accurate measurement of the friction coefficient of wire materials is achieved. The present invention not only overcomes the problems of insufficient measurement accuracy or complex operation in the prior art, but also provides a general testing platform applicable to the friction performance evaluation of various types of wire materials. At the same time, the present invention can accurately measure the friction coefficient while maintaining the original morphology and structure of the wire materials, providing an important basis for wire material performance evaluation and optimization.

[0008] The present invention solves its technical problems by adopting the following technical solutions:

[0009] A wire self-friction coefficient measurement system includes a pulley assembly, a bearing, a slide rail, and a base. Among them, a square groove is provided at the top of the base, the bearing is installed in the square groove and fixed, slide rails are respectively provided at both ends of the top of the base, the two slide rails and the bearing are arranged horizontally and coaxially, and the pulley assembly is arranged above the base.

[0010] Moreover, it also includes a wound wire, and the wound wire is wound around the side wall of the bearing.

[0011] Moreover, fixing holes are provided at both ends of the side wall of the bearing. One end of the wound wire is inserted into the fixing hole at one end of the side wall of the bearing, the wound wire is wound around the side wall of the bearing, and the other end of the wound wire is inserted into the fixing hole at the other end of the side wall of the bearing.

[0012] Moreover, a groove is provided at the top of the bearing to prevent a single wire from contacting the bearing.

[0013] Moreover, it further includes a bolt which is used to insert into the fixing holes at both ends of the side wall of the bearing and simultaneously fix both ends of the wound wire.

[0014] Moreover, one end of the bolt is thick and the other end is thin, and the thin end is inserted into the fixing holes at both ends of the side wall of the bearing.

[0015] Moreover, the pulley assembly includes an external clamping device and a pulley. A fixed shaft is arranged inside the external clamping device, and the pulley is installed in the middle of the external clamping device through the fixed shaft.

[0016] Moreover, it further includes a single wire. The single wire is placed between two slide rails, contacts the wound wire below, and is in point contact with the pulley above.

[0017] A measuring method for the self-friction coefficient of a wire includes the following steps:

[0018] Step 1: Tightly wind the wound wire around the bearing, and pass both ends of the wound wire through the small holes on both sides of the bearing.

[0019] Step 2: Insert the bolt into the small holes of the bearing to fix the wound wire.

[0020] Step 3: Install the bearing with the wound wire wound and fixed on the base.

[0021] Step 4: Clamp the pulley assembly and the base respectively through the upper and lower clamps of the tensile testing machine.

[0022] Step 5: Place a single wire on the slide rail of the base, and connect one end of the single wire to a force sensor.

[0023] Step 6: Slowly move the position of the clamp of the tensile testing machine to make the pulley contact the single wire and come into contact and extrusion with the wound wire, so as to form an extrusion force F between the single wire and the wound wire. n ;

[0024] Step 7: Slowly horizontally pull the single wire to be measured in the middle, and the force obtained by the force sensor is the dynamic friction force F between the single wire and the wound wire. τ ;

[0025] Step 8: Step 8: Calculate the friction coefficient of the wire according to μ = F τ / F n Change the position of the clamp of the tensile testing machine and simultaneously change the extrusion force F n , obtain multiple groups of friction force F τ data, and plot the obtained multiple groups of friction force F τ data with F τ as the vertical axis and F nIn a coordinate system with the horizontal axis, linear fitting is performed on the data scatter points, and the slope of the obtained fitting line is the friction coefficient. By fitting multiple data, the error in a single measurement can be effectively reduced, thereby improving the measurement accuracy of the friction coefficient.

[0026] The advantages and positive effects of the present invention are as follows:

[0027] 1. In the present invention, the wire to be measured is tightly wound around the bearing and fixed with a pin; the bearing is installed in the groove of the base; the tensile testing machine is used to clamp and fix the pulley assembly and the base respectively; a wire to be measured is placed between the base slide rails, and one end of it is connected to the force sensor; by adjusting the distance between the clamps of the tensile testing machine, the pulley assembly exerts a squeezing effect on the wound wire, thereby squeezing the wire to be measured on the slide rails; the extrusion force is obtained by reading the indication of the tensile testing machine, and the friction force between the wires is obtained through the force sensor, and the friction coefficient of the wire to be measured is calculated. The present invention not only overcomes the problems of insufficient measurement accuracy or complex operation in the prior art, but also provides a general test platform suitable for evaluating the friction performance of various types of wires.

[0028] 2. During the testing process of the present invention, there is no need to shear, flatten or perform other destructive treatments on the wire, and the original morphology and internal structural characteristics of the wire can be maintained. This is particularly important for wires with braided, wound or complex fiber arrangements, which helps to measure the friction coefficient closer to the actual use state.

[0029] 3. By adopting the winding and point-contact design, the present invention can accurately simulate the contact form of the wire in the actual working condition (such as point contact or local contact). Since the pulley assembly is designed to rotate freely and has a point contact with the wire, the present invention effectively reduces the test error caused by the friction force between the pulley and the wire, ensures that the friction force measured by the force sensor is more accurate, and further improves the credibility of the measurement. At the same time, by using the tensile testing machine to provide an accurately controllable extrusion force Fn and the friction force Fτ measured by the force sensor, the true friction coefficient between the wires can be calculated efficiently, ensuring the accuracy and reliability of the test results.

[0030] 4. The present invention is applicable to various types of wires, including wires with different diameters, materials, surface treatment methods and structural characteristics. Whether it is a single wire or a composite wire, its friction performance can be tested by the present invention, and it has a wide range of applications.

[0031] 5. By adjusting the distance between the clamps of the tensile testing machine, the present invention can change the extrusion force Fn between the wires, thereby obtaining the friction force Fτ under different loading conditions and forming multiple groups of test data. This multi-condition testing helps to more comprehensively evaluate the friction characteristics of the wire and further improve the accuracy of the measured friction coefficient.

[0032] 6. The structure design of the test system is simple, including basic components such as pulley assemblies, bearings, pins, and bases, which are easy to assemble and operate. At the same time, combined with the standardized fixture operation of the tensile testing machine, the test steps are intuitive and simple, without the need for complex instrument adjustment or special technical training. Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the specific structure of the wire self-friction coefficient measurement system;

[0034] Figure 2 It is a schematic diagram of the bearing and the wire wound around the bearing;

[0035] Figure 3 It is a schematic diagram of the pin;

[0036] Figure 4 It is a schematic diagram of the base and the slide rail of the present invention;

[0037] (a) is the front view of the base and the slide rail; (b) is the side view of the base and the slide rail;

[0038] Figure 5 It is a schematic diagram of the application directions of the extrusion force and the dynamic friction force in the wire self-friction coefficient measurement system;

[0039] Figure 6 It is a specific experimental picture;

[0040] Figure 7 It is a friction coefficient test data diagram of a specific wire (fishing line).

[0041] Label Description:

[0042] 1 - Pulley; 2 - External clamping device; 3 - Bearing; 4 - Pin; 5 - Base; 6 - Slide rail; 7 - Coiled wire; 8 - Single wire. Detailed Embodiment

[0043] The following further describes the present invention in conjunction with the drawings.

[0044] A wire self-friction coefficient measurement system, as shown in Figure 1 and Figure 6 , includes a pulley assembly, a bearing 3, a slide rail 6, and a base 5. Among them, a square groove is provided at the top of the base, and the bearing is installed and fixed in the square groove. As shown in Figure 4 (a), slide rails are respectively provided at both ends of the top of the base, and the two slide rails and the bearing are arranged in a horizontal coaxial direction. As shown in Figure 4 (b), the side view of the installation of the base and the slide rail shows that the horizontal plane of the slide rail is slightly higher than the horizontal plane of the base, which can ensure that there is no sliding friction between the single wire to be measured and the base. The pulley assembly is arranged above the base, and at the same time, the base is clamped and fixed by the tensile testing machine.

[0045] As Figure 2 shown, fixing holes are provided at both ends of the bearing side wall. One end of the winding wire is inserted into the fixing hole at one end of the bearing side wall, and the winding wire 8 is tightly wound around the side wall of the bearing. The other end of the winding wire is inserted into the fixing hole at the other end of the bearing side wall. A groove is provided at the top of the bearing to prevent a single wire from contacting the bearing.

[0046] As Figure 3 shown, the pin 4 is used to insert into the fixing holes at both ends of the bearing side wall, and at the same time fix both ends of the winding wire. One end of the pin is thick and the other end is thin. After the winding wire passes through the small hole of the bearing, the pin is inserted into the hole to fix the winding wire and prevent it from coming out.

[0047] The pulley assembly includes a pulley 1 and an external clamping device 2. A fixed shaft is provided inside the external clamping device. The pulley is installed in the middle of the external clamping device through the fixed shaft. The pulley can rotate freely in the external clamping device, and the external clamping device is used to fix the pulley in the fixture of the tensile testing machine.

[0048] The present invention further includes a single wire 7, wherein the single wire is placed between two slide rails, and the upper part of the single wire is in point contact with the pulley, so that the single wire is also in point contact with the winding wire and generates a squeezing force.

[0049] A measuring method for the self-friction coefficient of a wire includes the following steps:

[0050] Step 1: Tightly wind the winding wire around the bearing, and pass both ends of the winding wire through the small holes on both sides of the bearing;

[0051] Step 2: Insert the pin into the small hole of the bearing to fix the winding wire.

[0052] Step 3: Install the bearing around which the winding wire is wound and fixed on the base.

[0053] Step 4: Clamp the pulley assembly and the base respectively through the upper and lower fixtures of the tensile testing machine.

[0054] Step 5: Place a single wire on the slide rail of the base, and connect one end of the single wire to the force sensor.

[0055] Step 6: Slowly move the position of the fixture of the tensile testing machine to make the pulley contact the single wire and contact and squeeze the winding wire, so as to form a squeezing force F between the single wire and the winding wire n .

[0056] Step 7: As Figure 5As shown, by pulling one end of a single wire, the pulley rotates. The friction between the pulley and the single wire is rolling friction, and the frictional force is very small and can be ignored. Sliding friction occurs between the single wire and the wound wire, and the frictional force is the F measured by the force sensor. τ .

[0057] Step 8, Step 8, According to μ = F τ / F n Calculate the friction coefficient of the wire, change the position of the fixture of the tensile testing machine, and at the same time change the extrusion force F n , Obtain multiple groups of frictional force F τ data, and plot the obtained multiple groups of frictional force F τ data in a coordinate system with F τ as the vertical axis and F n as the horizontal axis. Perform linear fitting on the data scatter points, and the slope of the fitted straight line is the friction coefficient. Through the fitting of multiple data, the error in single measurement can be effectively reduced, thereby improving the measurement accuracy of the friction coefficient.

[0058] According to the above-mentioned wire self-friction coefficient measurement system and method, as Figure 7 shown, by performing corresponding friction coefficient measurements, the effects of the present invention have been verified. The experimental data of the present invention are shown in Table 1.

[0059] Table 1 Frictional force F corresponding to different extrusion forces F n data table τ

[0060]

[0061]

[0062] Taking polyvinylidene fluoride (PVDF) carbon wire as an example, the present invention has conducted 13 experiments in total. In the first experiment, the extrusion force was controlled at 0.1 N (directly input 0.1 N into the tensile testing machine, and the tensile testing machine will control the extrusion force at 0.1 N by adjusting the fixture spacing). Subsequently, horizontally pull the force sensor connected to one end of the carbon wire to make the carbon wire slide, and read the force value of the force sensor at this time as 0.04 N. 0.04 N is the dynamic frictional force when the extrusion force is 0.1 N. In subsequent experiments, the extrusion forces were controlled at 0.2 N, 0.4 N, 0.5 N, 0.8 N, 1 N, 1.2 N, 1.4 N, 1.6 N, 1.8 N, 2 N, 2.5 N, and 3 N respectively, and the corresponding dynamic frictional forces obtained were 0.06 N, 0.11 N, 0.13 N, 0.16 N, 0.18 N, 0.21 N, 0.24 N, 0.27 N, 0.28 N, 0.31 N, 0.37 N, and 0.47 N respectively.

[0063] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes, but is not limited to, the embodiments described in the specific embodiments. Any other embodiments obtained by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A wire self-friction coefficient measurement system, characterized in that: It includes a pulley assembly, a bearing, a slide rail and a base, wherein a square groove is provided on the top of the base, the bearing is installed in the square groove and fixed, slide rails are provided at both ends of the top of the base, the two slide rails and the bearing are arranged in a horizontal coaxial direction, and the pulley assembly is arranged above the base.

2. A wire self-friction coefficient measurement system according to claim 1, characterized in that: Also included is a winding wire, wherein the winding wire is wound around a side wall of the bearing.

3. A wire self-friction coefficient measurement system according to claim 2, characterized in that: The two ends of the bearing side wall are provided with fixing holes, one end of the winding wire is inserted into the fixing hole at one end of the bearing side wall, the winding wire is wound on the side wall of the bearing, and the other end of the winding wire is inserted into the fixing hole at the other end of the bearing side wall.

4. A wire self-friction coefficient measurement system according to claim 3, characterized in that: A groove is provided on the top of the bearing to prevent a single wire from contacting the bearing.

5. A wire self-friction coefficient measurement system according to claim 4, characterized in that: It also includes a latch pin, which is used to be inserted into the fixing holes at both ends of the bearing side wall, and fix the two ends of the winding wire at the same time.

6. A wire self-friction coefficient measurement system according to claim 5, characterized in that: One end of the latch is thick and the other end is thin, and the thin end is inserted into the fixing holes at both ends of the bearing side wall.

7. A wire self-friction coefficient measurement system according to claim 1, characterized in that: The pulley assembly comprises an external clamping device and a pulley. A fixed shaft is arranged inside the external clamping device, and the pulley is installed in the middle of the external clamping device through the fixed shaft.

8. A wire self-friction coefficient measurement system according to claim 7, characterized in that: Also included is a single wire, wherein the single wire is placed between two slide rails, the single wire is in contact with the winding wire at the bottom, and the single wire is in point contact with the pulley at the top.

9. A method for measuring the wire self-friction coefficient measurement system according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Wind the winding wire tightly on the bearing, and insert the two ends of the winding wire into the small holes on both sides of the bearing; Step 2: Insert the pin into the small hole of the bearing to fix the winding wire; Step 3, installing the bearing on which the winding wire is wound and fixed on the base; Step 4: Clamp the pulley assembly and the base respectively using the upper and lower clamps of the tensile testing machine; Step 5: Place a single wire on the slide rail of the base, and connect one end of the single wire to the force sensor; Step 6: Slowly move the clamp position of the tensile testing machine so that the pulley contacts the single wire and contacts and squeezes the wound wire, so that an extrusion force F is formed between the single wire and the wound wire. n ; Step 7: Slowly pull the single wire to be tested horizontally in the middle. The force obtained by the force sensor is the dynamic friction force F between the single wire and the winding wire. τ ; Step 8: According to μ=F τ / F n Calculate the friction coefficient of the wire, change the position of the tensile tester fixture, and change the extrusion force F at the same time n , obtain multiple sets of friction force F τ The data obtained are multiple sets of friction force F τ The data are plotted in F τ is the vertical axis, F n In the coordinate system with as the horizontal axis, a linear fit is performed on the data scatter points, and the slope of the fitted straight line is the friction coefficient.

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