A reciprocating motion-based pad friction test device

Abstract

The application discloses a gasket friction test device based on reciprocating motion, which comprises a rack and a pressure loading module, a tooling module and a reciprocating motion module fixed on the rack; the rack comprises a lower pressing mechanism upper plate, a middle support, a lower pressing mechanism lower plate, a reciprocating mechanism lower plate, a lower pressing mechanism lower support and a lower pressing mechanism upper support; the lower pressing mechanism upper plate, the middle support and the lower pressing mechanism lower plate are connected through the lower pressing mechanism upper support and the lower pressing mechanism lower support; and one end of the reciprocating mechanism lower plate is connected with one end of the lower pressing mechanism lower plate. The application has simple structure and high test precision; the testing machine can test two gaskets at the same time in one test, so that the test results of the two gaskets can be compared, the comparison of different test data is facilitated, and more data is provided for subsequent analysis.

Description

Technical Field

[0001] This invention relates to the field of tribological property testing of materials, and specifically to a pad friction testing device based on reciprocating motion. Background Technology

[0002] Fabric gaskets are one of the core materials and structures of self-lubricating spherical plain bearings. They possess self-lubricating properties, and their tribological performance determines the bearing's service life and reliability, making them a key foundational material for aerospace self-lubricating bearings. Fabric gaskets consist of three components: polytetrafluoroethylene (PTFE) fiber bundles, aramid fiber bundles (generally Kevlar aramid fiber bundles), and thermosetting resin. The PTFE fiber bundles primarily function as self-lubricants and reduce friction, Kevlar provides reinforcement and toughening, and the resin handles load transfer, bonding, and lubrication. Currently, my country's aerospace industry urgently needs to achieve independent research and development and supporting technologies. The bottleneck technical issues for these products are: how to achieve excellent tribological properties for fabric gaskets and high-quality clearance control in bearing manufacturing. To more accurately simulate the pressure friction of the gasket in the bearing clearance for comprehensive performance analysis, the testing and evaluation technology of its tribological performance is fundamental research for product development.

[0003] Most existing tribological testing machines are capable of performing friction and wear tests on materials with high stiffness. However, when used for testing more flexible materials like fabric pads, the material exhibits localized uneven deformation. For example, methods like pin friction can create a "pitting" effect. Damage to the fabric pad is not only caused by frictional conditions but also by scratches and tears due to uneven deformation. Furthermore, the fabric pad in a bearing experiences out-of-plane loading pressure throughout the bearing clearance. Current traditional testing machines cannot guarantee that the sample is completely subjected to this out-of-plane loading pressure. Therefore, traditional tribological testing machines, primarily used for testing high-stiffness materials, cannot accurately simulate the friction and wear conditions of fabrics or obtain precise results. Thus, there is a need to design a testing machine that can reflect the out-of-plane loading pressure and reciprocating motion of self-lubricating bearing fabric pads for tribological performance testing.

[0004] Patent CN104316424A discloses a friction fatigue testing machine for friction lifting machine linings, used to test lining samples. It can detect friction between the lining and the conveyor belt. However, since friction occurs between two flexible materials, it cannot test friction between the lining and metal. Furthermore, the deformation of the conveyor belt affects the accuracy of the loading speed and reciprocating frequency. For testing self-lubricating fabric linings used in high-frequency applications in aviation, the reciprocating motion is insufficient. Additionally, the loading module of this testing machine requires continuous adjustment of the servo push rod to maintain the loading force, which inevitably leads to operational fluctuations, low loading stability, and system complexity. It cannot accurately simulate the pressure friction condition of the lining within the bearing clearance. Currently, there is no method to solve this problem; therefore, there is an urgent need to research a lining friction testing machine that can overcome these technical deficiencies. Summary of the Invention

[0005] In view of the above-mentioned defects in the prior art, in order to overcome the shortcomings of the prior art, the present invention provides a liner friction test device based on reciprocating motion, which can more accurately simulate the out-of-surface loading and pressure friction of the liner in the bearing clearance, and perform comprehensive performance analysis of the liner under the requirements of high-speed reciprocating motion and pressure maintenance.

[0006] Specifically, the present invention provides a pad friction testing device based on reciprocating motion, which includes a frame and a pressure loading module, a tooling module and a reciprocating motion module fixed on the frame;

[0007] The frame includes an upper plate of the pressing mechanism, a middle support, a lower plate of the pressing mechanism, a lower plate of the reciprocating mechanism, a lower support of the pressing mechanism, and an upper support of the pressing mechanism. The upper plate of the pressing mechanism, the middle support, and the lower plate of the pressing mechanism are connected by means of the upper support of the pressing mechanism and the lower support of the pressing mechanism, respectively. One end of the lower plate of the reciprocating mechanism is connected to one end of the lower plate of the pressing mechanism.

[0008] The pressure loading module includes a rotary handle, a displacement flange seat, a one-way thrust ball bearing, a spring baffle, a nitrogen spring mounting bracket, a spring, and a nitrogen spring. The displacement flange seat is equipped with a rotary handle and a nitrogen spring mounting bracket. The upper side of the nitrogen spring mounting bracket is fixedly connected to the spring baffle, and the lower side of the nitrogen spring mounting bracket is fixedly connected to the nitrogen spring. The spring is arranged between the spring baffle and the displacement flange seat, and a one-way thrust ball bearing is arranged above the spring baffle.

[0009] The tooling module includes a linear bearing, a transmission column, a clamping column, an upper sample top head, and a lower sample top head. The transmission column is installed inside the linear bearing. The upper sample top head is fixedly connected to the lower side of the transmission column. The lower sample top head is fixedly connected to the upper side of the lower plate of the pressing mechanism. The clamping column is fixedly connected to the lower side of the middle support. A grinding steel plate is provided between the upper sample top head and the lower sample top head.

[0010] The pressure loading module and the tooling module are connected by a first threaded adapter, a first tension / compression sensor, and a second threaded adapter. The upper end of the first threaded adapter is connected to the lower end of the nitrogen spring, the lower end of the first threaded adapter is connected to the upper end of the first tension / compression sensor, the lower end of the first tension / compression sensor is connected to the upper end of the second threaded adapter, and the lower end of the second threaded adapter is connected to the upper end of the locking pin.

[0011] The reciprocating motion module includes a reciprocating mechanism mounting frame, a cylindrical spatial cam, a roller, a transmission slider, a transmission guide rail plate, a transmission guide rail column, a hinge base, a hinge head, a grinding steel plate, a servo motor, a reducer, and a coupling. The transmission guide rail plate, the transmission guide rail column, and the cylindrical spatial cam are mounted on the reciprocating mechanism mounting frame. The transmission slider is disposed on the transmission guide rail column. One side of the cylindrical spatial cam is connected to the coupling, the reducer, and the servo motor. The first end of the transmission slider is fixedly connected to the hinge base, and the second end of the transmission slider is fixedly connected to the roller. The cylindrical spatial cam has a groove, and the roller is disposed in the groove of the cylindrical spatial cam. The cylindrical spatial cam rotates under the drive of the servo motor, causing the transmission slider to move along the groove with the help of the roller. The transmission slider further drives the grinding steel plate to move.

[0012] A hinge head is connected to the hinge base. The first end of the hinge head is connected to the grinding steel plate via a third threaded adapter, a second tension / compression sensor, and a fourth threaded adapter. The second end of the hinge head is connected to the first end of the third threaded adapter. The second end of the third threaded adapter is connected to the first end of the second tension / compression sensor. The second end of the second tension / compression sensor is connected to the first end of the fourth threaded adapter. The second end of the fourth threaded adapter is connected to the grinding steel plate.

[0013] Preferably, the upper part of the inner wall of the displacement flange seat is a smooth cylindrical wall, and the lower part of the displacement flange seat is threaded.

[0014] Preferably, the lower outer surface of the rotary handle is threaded, and the thread of the lower part of the rotary handle is adapted to the thread of the lower part of the displacement flange seat.

[0015] Preferably, the one-way thrust ball bearing is placed between the rotating handle and the spring stop.

[0016] Preferably, the transmission slider makes sliding contact with the transmission guide plate and the transmission guide column respectively.

[0017] Preferably, the spring stop and the nitrogen spring mounting bracket are fixedly connected by screws.

[0018] Preferably, the groove of the cylindrical space cam is configured as a cylindrical unfolded groove with one cycle, and the groove has two structures: parabolic-straight-parabolic groove and sinusoidal groove.

[0019] Preferably, the parabolic-straight-parabolic groove motion trajectory is as follows: within one period of 180°, there are four working stages, namely the pushing stroke, stopping, returning stroke and stopping stage. The pushing stroke motion is from 0° to 140°, and the parabolic motion is from 0° to 20°, with constant acceleration and increasing speed.

[0020] Within the range of 20°-120°, the motion is uniform linear motion with zero acceleration. At this time, the value measured by the tension and compression sensor connected to the grinding steel plate is the frictional force received by the steel plate.

[0021] The motion is parabolic within the range of 120°-140°, with acceleration, and the velocity gradually decreases to 0.

[0022] The stopping phase is within the range of 140°-180°.

[0023] Preferably, the motion trajectory of the sinusoidal groove is as follows: within one cycle of 360°, there are two working stages, namely the push stroke and the return stroke, with the acceleration being a sine curve and the velocity and displacement curves being trigonometric function curves.

[0024] Preferably, both the upper and lower sample tops are provided with grooves for attaching the test liner, the thickness h of the test liner is 0.25mm ≤ h ≤ 0.4mm, and the groove depth δ is calculated according to the following formula: Where h is the thickness of the test liner, and h is 0.25mm≤h≤0.4mm;

[0025] The surface roughness R of the groove opening a Satisfies 1.6 <R a <6.3, the flatness of the bottom of the groove is 0.010.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] (1) In this invention, nitrogen springs are installed so that the pad placement platform can maintain close contact with the grinding steel plate at all times during use. Compared with the loading method of electric servo push rod, it can play a role in maintaining pressure. Even when the pad is slightly worn, it can still maintain the same pressure value and maintain the accuracy of the test data.

[0028] (2) The present invention can convert the rotational motion of the motor into a high-speed reciprocating motion on the grinding steel plate by installing a cylindrical space cam and a slider. It can also simulate the loading and movement of the pad under real working conditions, thereby meeting the test requirements of the grinding steel plate. The overall structure is simple and reliable, and can ensure the accuracy of the test.

[0029] (3) The testing machine of the present invention can test two gaskets at the same time in one test, thereby enabling a comparison of the test results of the two gaskets. It can simulate the wear of gaskets in different parts of the bearing, facilitate the comparison of results of different test data, and provide more data for subsequent analysis.

[0030] (4) The present invention provides grooves of different forms on the cylindrical cam. By adopting a sinusoidal motion trajectory, the reciprocating speed of the grinding steel plate can be increased. At the same time, increasing the motor speed or machining multiple cycles of grooves on a cylindrical cam surface can accelerate the movement rate of the grinding steel plate. It can simulate the load conditions of the liner under many different operating conditions. Attached Figure Description

[0031] Figure 1 This is an enlarged schematic diagram of the internal structure of the displacement flange seat of the present invention;

[0032] Figure 2 This is a schematic front view of the pad friction testing device based on reciprocating motion according to the present invention.

[0033] Figure 3 This is a three-dimensional structural schematic diagram of the pad friction testing device based on reciprocating motion according to the present invention;

[0034] Figure 4 This is a top view of the reciprocating structure of the present invention;

[0035] Figures 5a-5c This is a schematic diagram of the unfolded side of the cylindrical space cam of the present invention;

[0036] Figure 6 This is a schematic diagram of the pad placement platform structure of the present invention;

[0037] Figure 7 This is a schematic diagram of the grinding steel plate placement structure of the present invention.

[0038] Some of the reference numerals in the figure are as follows: 1-Rotating handle, 2-Displacement flange seat, 3-One-way thrust ball bearing, 4-Spring baffle, 5-Upper plate of the pressing mechanism, 6-Spring, 7-Nitrogen spring mounting bracket, 8-Nitrogen spring, 9-First thread conversion component, 10-First tension / compression sensor, 11-Second thread conversion component, 12-Central support, 13-Linear bearing, 14-Clamping post, 15-Transmission column, 16-Upper sample top, 17-Grinding steel plate, 18-Lower sample top, 19-Pressing mechanism 20-Third thread conversion component, 21-Second tension / compression sensor, 22-Fourth thread conversion component, 23-Hinge head, 24-Hinge base, 25-Transmission guide rail plate, 26-Transmission slider, 27-Transmission guide rail column, 28-Reciprocating mechanism mounting bracket, 29-Cylindrical space cam, 30-Reciprocating mechanism lower plate, 31-Servo motor, 32-Reducer, 33-Coupling, 34-Lower support of pressing mechanism, 35-Upper support of pressing mechanism, 36-Roller; 37-Pad. Detailed Implementation

[0039] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0040] This invention provides a pad friction testing device based on reciprocating motion, such as... Figures 1 to 4 As shown, the frame includes an upper plate 5 for the pressing mechanism, a middle support 12, a lower plate 19 for the pressing mechanism, a lower plate 30 for the reciprocating mechanism, a mounting frame 28 for the reciprocating mechanism, a lower support 34 for the pressing mechanism, and an upper support 35 for the pressing mechanism. The upper plate 5 for the pressing mechanism, the middle support 12, the lower plate 19 for the pressing mechanism, the lower plate 30 for the reciprocating mechanism, the mounting frame 28 for the reciprocating mechanism, the lower support 34 for the pressing mechanism, and the upper support 35 for the pressing mechanism are connected to each other to form an overall frame.

[0041] The upper plate 5 of the pressing mechanism has a displacement flange seat 2 embedded inside. The inner wall of the displacement flange seat 2 is threaded, and a rotary handle 1, a spring stop plate 4, and a nitrogen spring mounting bracket 7 are installed inside the displacement flange seat 2. The lower part of the rotary handle 1 is threaded, and the thread of the lower part of the rotary handle 1 can be adapted to the thread of the inner wall of the displacement flange seat 2. The spring stop plate 4 and the nitrogen spring mounting bracket 7 are fixedly connected by screws for easy installation and disassembly. The lower side of the nitrogen spring mounting bracket 7 is fixedly connected to the nitrogen spring 8 through a threaded hole on the side. A one-way thrust ball bearing 3 is installed between the rotary handle 1 and the spring stop plate 4 to ensure that the spring stop plate 4 does not rotate when the rotary handle 1 is turned. A spring 6 is installed between the spring stop plate 4 and the displacement flange seat 2 to ensure that the spring stop plate 4 is always in contact with the one-way thrust ball bearing 3.

[0042] A linear bearing 13 is installed inside the central support 12, and a retaining post 14 is fixedly installed on the lower side of the central support 12. The retaining post 14 ensures that the transmission column 15 does not rotate during operation. The inner wall of the linear bearing 13 contacts the transmission column 15, and the linear bearing 13 serves as a guide. An upper sample head 16 is installed on the lower side of the transmission column 15. The upper sample head 16 has a groove for attaching a pad for the test. A tension / compression sensor 10 connects the nitrogen spring 8 and the upper sample head 16. A lower sample head 18 is installed on the lower plate 19 of the lower pressing mechanism. The lower sample head 18 also has a groove for attaching a pad.

[0043] The reciprocating mechanism mounting bracket 28 and the reducer 32 are fixed to the reciprocating mechanism lower plate 30. A spatial cylindrical cam 29, a transmission guide plate 25, and a transmission guide column 27 are mounted on the reciprocating mechanism mounting bracket 28. A transmission slider 26 is mounted on the transmission guide column 27. The right side of the spatial cylindrical cam 29 is connected to the coupling 33. A hinge base 24 is mounted on the first end of the transmission slider 26, and a roller 36 is connected to the second end of the transmission slider 26. The reducer 32 is connected to the right side of the coupling 33, and a servo motor 31 is connected to the right side of the reducer 32. The output shaft of the servo motor 31 is connected to the reducer 32, driving the spatial cylindrical cam 29 to move. The hinge base 24 engages with the first end of the hinge head 23, and the second end of the hinge head 23 is connected to the grinding steel plate 17 via a tension / compression sensor. The roller 29 is placed within the groove of the spatial cylindrical cam 26. When the spatial cylindrical cam 26 rotates, the roller 29 drives the grinding steel plate 17 to move with the help of the transmission slider 26. By setting grooves of different groove types, the movement speed and movement amplitude of the grinding steel plate 17 can be adjusted.

[0044] Specifically, the pressure loading module and the tooling module are connected by a first threaded adapter 9, a first tension / compression sensor 10, and a second threaded adapter 11. The upper end of the first threaded adapter 9 is connected to the lower end of the nitrogen spring, the lower end of the first threaded adapter 9 is connected to the upper end of the first tension / compression sensor 10, the lower end of the first tension / compression sensor 10 is connected to the upper end of the second threaded adapter 11, and the lower end of the second threaded adapter 11 is connected to the upper end of the locking post.

[0045] A hinge head 23 is connected to the hinge base. The first end of the hinge head 23 is connected to the grinding steel plate via a third threaded adapter 20, a second tension / compression sensor 21, and a fourth threaded adapter 22. The second end of the hinge head 23 is connected to the first end of the third threaded adapter 20. The second end of the third threaded adapter 20 is connected to the first end of the second tension / compression sensor 21. The second end of the second tension / compression sensor 21 is connected to the first end of the fourth threaded adapter 22. The second end of the fourth threaded adapter 22 is connected to the grinding steel plate.

[0046] like Figures 5a to 5cAs shown, the cylindrical space cam 29 has two groove types available. The first groove type is as follows: Figure 5a As shown, the groove is a parabolic-straight-parabolic curve. With this groove shape, the pushing and returning motions of the rollers and the grinding steel plates are uniform oscillations, with a parabolic transition section between the pushing and returning motions and the stopping section. The motion trajectory of this groove shape is as follows: Figure 5b .

[0047] The second type of groove is a sinusoidal groove. When using the second type of groove, the push and return strokes of the rollers and the grinding steel plates are as follows: Figure 5c It is a sinusoidal oscillation, at which point the roller and the grinding steel plate can achieve high-speed reciprocating motion.

[0048] The specific motion trajectory of the parabolic-linear-parabolic grooved roller and transmission slider 26 is as follows: Within one cycle, there are four working stages: push stroke, stop, return stroke, and stop. The push stroke occurs from 0° to 140°. From 0° to 20°, it is parabolic motion with constant acceleration, and the speed increases. From 20° to 120°, it is uniform linear motion with zero acceleration; the value measured by the tension / compression sensor connected to the grinding steel plate at this time is the frictional force received by the steel plate. From 120° to 140°, it is parabolic motion with acceleration, and the speed gradually decreases to 0. The stop stage occurs from 140° to 180°. The last two steps are similar to the first two. During this process, the magnitude of acceleration changes abruptly, preventing high-speed motion.

[0049] The specific motion trajectory of the sinusoidal groove type roller drive slider 26 is as follows: Figure 5c The motion follows a sinusoidal acceleration pattern. Within a 360° cycle, there are two working phases: the push stroke and the return stroke. Its motion is characterized by smooth acceleration changes and no impact during overall operation, thus ensuring high-speed motion. Its acceleration is sinusoidal, while its velocity and displacement curves are trigonometric function curves. The designed displacement curve does not include a stationary phase. During motion, there is no uniform velocity phase; therefore, the values ​​measured by the tension / compression sensor are not frictional force, and the data needs to be converted from electrical signals to force signals.

[0050] In practical applications, the parabolic-linear-parabolic groove shape is suitable for high-speed, impact-prone tests, while the sinusoidal groove shape is suitable for lower-speed, non-impact tests. Depending on the test requirements, cylindrical space cams with different groove shapes can be selected.

[0051] like Figure 6 and Figure 7 As shown, grooves for attaching the test liner are machined on the top and bottom of the upper and lower test specimens. The liner thickness h is generally 0.25mm ≤ h ≤ 0.4mm, and the groove depth δ is specified as follows: Because the groove is used to attach test liners, it needs to facilitate liner attachment without causing additional problems. Therefore, the groove surface must be sandblasted with fine sand of 800 mesh or higher, and the surface roughness must meet a requirement of 1.6. <R a <6.3, and the flatness of the bottom of the groove is specified to be 0.010.

[0052] The working principle of the present invention will be further described below with reference to embodiments:

[0053] First, grooves for attaching the test liner are machined on the top of the upper and lower specimens. The liner thickness h is 0.3 mm, and the groove depth δ is... The surface of the tank is sandblasted with 900-mesh fine sand, resulting in a surface roughness of 3.5 and a flatness of 0.010 at the tank opening and bottom.

[0054] Next, attach the two test pads to the slots of the upper sample head 16 and the lower sample head 18, respectively. Turn the rotating handle 1 downwards, causing the nitrogen spring 8 and the transmission column 15 to move downwards, so that the pad 37 on the upper sample head 16 presses tightly against the grinding steel plate. When the pressure reaches the required test pressure value, stop turning, so that both pads are in close contact with the grinding steel plate 17.

[0055] Next, the servo motor 31 is started, driving the cylindrical space cam 29 to rotate, which in turn drives the transmission slider 26 to reciprocate, and finally drives the grinding steel plate 17 to reciprocate. The tension and compression sensor 21 can measure the frictional force between the grinding steel plate 17 and the pad during the test. When the pad wears, the nitrogen spring 8 can be finely adjusted to ensure that the test pressure remains constant. The design of the hinge base 24 and hinge head 23 ensures that the force of the upper sample top can be transmitted to the pad of the lower sample top through the grinding steel plate.

[0056] In this embodiment, the servo motor model is IMB14H80-112, with a power of P = 1.1KW, and it adopts an end-face mounting method with a rated speed of n = 1500rpm. The reduction ratio of the reducer is i = 5, so the cam speed n1 = n / i = 300rpm, or n1 = 5r / s, can be obtained. The reciprocating motion frequency of the grinding steel plate is f = 0.2Hz.

[0057] This experiment is a high-speed impact test; therefore, the groove of the cylindrical spatial cam 29 adopts a parabolic-linear-parabolic groove shape. The roller moves within this groove shape and drives the grinding plate to move. In other embodiments, if it is necessary to increase the reciprocating speed, the groove of the cylindrical spatial cam 29 adopts a sinusoidal groove shape. Using a sinusoidal motion trajectory can increase the reciprocating speed of the grinding plate. At the same time, increasing the motor speed or machining multiple cycles of grooves on a cylindrical cam surface can accelerate the movement rate of the grinding plate.

[0058] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A reciprocating-based pad friction test apparatus, characterized by: It includes frame and fixed on the frame pressure loading module, tooling module and reciprocating module; The frame includes lower pressing mechanism upper plate, middle support, lower pressing mechanism lower plate, reciprocating mechanism lower plate, lower pressing mechanism lower support and lower pressing mechanism upper support, the lower pressing mechanism upper plate, the middle support and the lower pressing mechanism lower plate are connected by means of lower pressing mechanism upper support and lower pressing mechanism lower support, one end of the reciprocating mechanism lower plate is connected with one end of the lower pressing mechanism lower plate; The pressure loading module includes rotating handle, displacement flange seat, one-way thrust ball bearing, spring stop piece, nitrogen spring mounting bracket, spring and nitrogen spring, the rotating handle and nitrogen spring mounting bracket are arranged in the displacement flange seat, the spring stop piece is fixedly connected to the upper side of the nitrogen spring mounting bracket, the nitrogen spring mounting bracket is fixedly connected with the nitrogen spring at the lower side, the spring is arranged between the spring stop piece and the displacement flange seat, the one-way thrust ball bearing is arranged above the spring stop piece; The tooling module includes linear bearing, transmission column, clamping column, upper sample head and lower sample head, the transmission column is installed in the linear bearing, the upper sample head is fixedly connected to the lower side of the transmission column, the lower sample head is fixedly connected to the upper side of the lower pressing mechanism lower plate, the clamping column is fixedly connected to the lower side of the middle support, the pair of grinding steel plates are arranged between the upper sample head and the lower sample head; The pressure loading module and the tooling module are connected by means of first threaded conversion piece, first tension and pressure sensor and second threaded conversion piece, the upper end of the first threaded conversion piece is connected with the lower end of the nitrogen spring, the lower end of the first threaded conversion piece is connected with the upper end of the first tension and pressure sensor, the lower end of the first tension and pressure sensor is connected with the upper end of the second threaded conversion piece, and the lower end of the second threaded conversion piece is connected with the upper end of the clamping column; The reciprocating module includes reciprocating mechanism mounting bracket, cylindrical space cam, roller, transmission sliding block, transmission guide rail plate, transmission guide rail column, hinge base, hinge head, pair of grinding steel plates, servo motor, speed reducer and shaft coupling, the transmission guide rail plate, the transmission guide rail column and the cylindrical space cam are installed on the reciprocating mechanism mounting bracket, the transmission sliding block is arranged on the transmission guide rail column, the cylindrical space cam is connected with the shaft coupling, the speed reducer and the servo motor on one side, the hinge base is fixedly connected to the first end of the transmission sliding block, the roller is fixedly connected to the second end of the transmission sliding block, the cylindrical space cam is provided with a groove, the roller is arranged in the groove of the cylindrical space cam, and the cylindrical space cam rotates under the drive of the servo motor to drive the transmission sliding block to move along the groove by means of the roller, and the transmission sliding block further drives the pair of grinding steel plates to move. The hinge base is connected with a hinge head, the first end of the hinge head is connected with a pair of grinding steel plates through a third screw conversion piece, a second tension and pressure sensor and a fourth screw conversion piece, the second end of the hinge head is connected with the first end of the third screw conversion piece, the second end of the third screw conversion piece is connected with the first end of the second tension and pressure sensor, the second end of the second tension and pressure sensor is connected with the first end of the fourth screw conversion piece, and the second end of the fourth screw conversion piece is connected with the pair of grinding steel plates.

2. The reciprocating-based pad friction test apparatus of claim 1, wherein: The upper part of the inner wall of the displacement flange base is a smooth cylinder wall, and the lower part of the displacement flange base is a screw thread.

3. The reciprocating-based pad friction test apparatus of claim 2, wherein: The outer surface of the lower part of the rotating handle is a screw thread, and the screw thread of the lower part of the rotating handle is matched with the screw thread of the lower part of the displacement flange base.

4. The reciprocating-based pad friction test apparatus of claim 1, wherein: The one-way thrust ball bearing is arranged between the rotating handle and the spring stop piece.

5. The reciprocating-based pad friction test apparatus of claim 1, wherein: The transmission sliding block is in sliding contact with the transmission guide rail plate and the transmission guide rail column, respectively.

6. The reciprocating-based pad friction test apparatus of claim 1, wherein: The spring stop piece and the nitrogen gas spring mounting frame are fixedly connected through screws.

7. The reciprocating-based pad friction test apparatus of claim 1, wherein: The groove of the cylindrical space cam is arranged as a cylindrical surface development groove with one period, and the groove type has two structures of a parabola-straight line-parabola groove type and a sine groove type.

8. The reciprocating-based pad friction test apparatus of claim 1, wherein: The movement trajectory of the parabola-straight line-parabola groove type is that there are four working stages in one period of 180°, which are respectively a pushing stage, a stopping stage, a returning stage and a stopping stage, and in 0°-140°, the pushing movement is a parabola movement, and there is a constant acceleration, and the speed rises; In 20°-120°, it is a uniform linear motion, and the acceleration is zero, at this time, the value measured by the tension and pressure sensor connected with the grinding steel plate is the friction received by the steel plate; In 120°-140°, it is a parabola movement, and there is an acceleration, and the speed gradually decreases to 0; In 140°-180°, it is a stopping stage.

9. The reciprocating-based pad friction test apparatus of claim 1, wherein: The movement trajectory of the sine groove type is that there are two working stages in one period of 360°, which are respectively a pushing stage and a returning stage, the acceleration is a sine line, and the speed and displacement curves are triangular function curves.

10. The reciprocating-based pad friction test device of claim 1, wherein: The upper and lower sample heads are provided with notches for pasting test pads, the thickness h of the test pad is 0.25mm≤h≤0.4mm, and the notch depth δ is calculated according to the following formula: Wherein h is the thickness of the test pad, and h is 0.25mm≤h≤0.4mm. The groove roughness R a satisfies 1.6 < R a <6.3, the groove bottom flatness is 0.010.

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