CN106680199B - Friction resistance coefficient testing device based on hydraulic drive - Google Patents

Abstract

The invention discloses a friction resistance coefficient testing device based on hydraulic drive, which comprises a torque testing device, a pressure testing device, a base and a controller, wherein the torque testing device is fixedly connected with the base, the pressure testing device is in sliding connection with the base, and the sliding center line of the pressure testing device and the axis of the torque testing device are in the same vertical plane; the signal output end of the torque testing device and the signal output end of the pressure testing device are respectively and electrically connected with the corresponding signal input end of the controller. The beneficial effects of the invention are as follows: the test piece is fixed by adopting the threaded connection between the shaft and the test piece, the fixing mode is simple, the whole experimental device structure is more compact, and the threaded connection adopts the direction opposite to the motor steering direction; the hydraulic drive lifting device is introduced to adjust the upper and lower positions of the test head, so that the defects of low manual adjustment speed, labor waste and the like are avoided. Limiting the left movement of the sliding block can be realized only by controlling the position of the baffle plate, and the operation is simple and convenient.

Description

A friction resistance coefficient testing device based on hydraulic drive

Technical field

The invention relates to a friction resistance coefficient testing device based on hydraulic drive. Specifically, it is a testing device capable of testing the surface friction coefficient of a solid wall. It is especially suitable for testing the frictional resistance coefficient of solid wall surfaces with different roughness surfaces, and testing the frictional resistance coefficient of bionic non-smooth surfaces.

Background technique

Frictional resistance has always been a hot topic studied by experts and scholars at home and abroad. Frictional resistance can be summarized into three categories: friction between solid and solid surface, friction between fluid and solid surface, and friction between fluid and fluid. The existence of frictional resistance will greatly increase energy consumption and lead to energy waste. There are many factors that affect friction, the key factor being the frictional resistance coefficient. The frictional resistance coefficients of different materials are generally different. Usually, the methods to study the friction coefficient mainly include experimental methods and theoretical analysis. Theoretical analysis is mostly used in relatively simple situations, and various assumptions need to be introduced to simplify the problem. For complex problems, it is difficult to make abstract assumptions due to the large number of influencing factors. Therefore, experimental methods are mostly used for research. When studying the frictional resistance between a fluid and a solid wall, the most commonly used test device is a water tunnel or a wind tunnel according to the properties of the fluid. However, there are not many test devices for the friction coefficient of solid surfaces.

Contents of the invention

In order to solve the current problem of lack of corresponding testing devices when studying the frictional resistance of solid walls, the present invention proposes a method that can be used not only to test the frictional resistance coefficient of solid wall surfaces with different roughness surfaces, but also to test the frictional resistance of bionic non-smooth surfaces. A hydraulically driven friction resistance coefficient testing device for testing coefficients.

The friction resistance coefficient testing device based on hydraulic drive according to the present invention is characterized in that it includes a torque testing device, a pressure testing device, a base and a controller. The torque testing device is fixedly connected to the base, and the pressure testing device is fixedly connected to the base. The testing device is slidingly connected to the base, and the sliding center line of the pressure testing device and the axis of the torque testing device are in the same vertical plane; the signal output end of the torque testing device and the signal output of the pressure testing device terminals are electrically connected to corresponding signal input terminals of the controller;

The torque testing device includes a driving device for providing rotational driving force, a transmission unit for transmitting driving force, a test unit for installing a test piece, and a torque testing unit for measuring the torque of the transmission unit. The driving device, The test unit is coaxially installed on the base, and the output shaft of the driving device is fixedly connected to the test unit through a transmission unit to realize the transmission of driving force; the test end of the torque test unit is attached to the The surface of the transmission unit; the signal output end of the torque test unit is electrically connected to the controller;

The pressure testing device includes a bottom frame, a lifting device for adjusting the height of the test end, and a pressure testing unit for pressing on the surface of the test piece. The bottom frame is slidingly connected to the base, and the bottom of the lifting device is connected to the The bottom frame is fixed, and the pressure test unit is installed on the top of the lifting device; the free end of the pressure test unit is equipped with a test head for pressing on the surface of the test piece, and the signal output end of the pressure test unit is connected to the The second signal input terminal of the controller is electrically connected.

The transmission unit is a sleeve-type connecting shaft. The connecting shaft is axially provided with through holes that penetrate both end surfaces of the connecting shaft. One end of the connecting shaft is keyed to the output shaft of the driving device; the other end of the connecting shaft is It is keyed to the installation shaft of the test unit; the center lines of the driving device, the transmission unit and the test unit coincide to ensure that the force transmission is linear transmission.

The test unit includes a cylinder, a rotating connecting shaft, a bearing end cover and a bearing. The cylinder is installed on the base through a support frame. Bearings for horizontally supporting the rotating connecting shaft are installed at both ends of the inner cavity of the cylinder. The two end faces of the cylinder are respectively fixed with bearing end caps for preventing the axial movement of the bearing; the two ends of the rotary connection shaft pass through the center through holes of the corresponding bearing end caps, and the rotary connection shaft is connected with the corresponding The bearing end cover is sealed and rotated, and the barrel, the rotating connecting shaft and the bearing end cover form a rotating pair with a sealed cavity; one end of the rotating connecting shaft is keyed to one end of the connecting shaft, and the other end is keyed to the connecting shaft. Install the test piece on one end.

The torque test unit includes a strain gauge and a plurality of resistive strain gauges. The resistive strain gauges are attached to the outer wall of the connecting shaft. The signal output end of the resistive strain gauges is connected to the strain gauge through a half-bridge circuit. The signal input terminal is electrically connected; the signal output terminal of the strain gauge is electrically connected to the first signal input terminal of the controller.

The base frame includes a slide rail, a slide block and a baffle for blocking the slide block. The slide rail is laid on the base, and the slide rail is fixedly connected to the base to ensure the alignment between the center line of the slide rail and the torque testing device. The axes are in the same vertical plane; the slide block is inserted into the slide rail through the opening at one end of the slide rail to ensure that the slide block slides along the center line of the slide rail; the slide rail is provided along the direction of its cross section for inserting the stopper strip seams.

The pressure test unit includes a test board, a test head and a strain gauge pressure sensor. One end of the test board is fixed to the top of the lifting device, and the other end is equipped with a strain gauge pressure sensor. Each strain gauge pressure sensor is configured with one for testing. A pressure test head; the signal output end of the strain gauge pressure sensor is electrically connected to the second signal input end of the controller.

The lifting device is a hydraulically driven lifting column, including an outer cylinder and an inner core. The bottom of the outer cylinder is fixedly connected to the slider of the chassis; the lower end of the inner core is inserted into the inner cavity of the outer cylinder and slides with it. connection, the top of the inner core is fixedly connected to the test plate of the pressure test unit; the sealing gap between the inner core and the outer cylinder is filled with lubricating fluid.

The test board is divided into a circular disk for adjusting the horizontal rotation angle of the test head and a cuboid for installing the test head; the circular disk of the test board is embedded in a circular hole with a radius equivalent to the radius of the circular disk provided on the top of the inner core And fixed by bolts, the cuboid of the test plate extends from the installation hole opened on the top side of the inner core; the test plate is placed on the inner core of the lifting device through the circular hole and the side installation hole; the right side of the cuboid end of the test plate and Each of the lower sides is connected to a strain gauge pressure sensor; the strain gauge pressure sensor on the right side is connected to a cylindrical test head for testing specimens with a flat surface, and the strain gauge pressure sensor on the lower side is connected to a cylindrical test head for testing arc-shaped specimens. The arc-shaped test heads of the pressure on the surface and the bionic non-smooth surface are connected together; the signal output end of the strain gauge pressure sensor is electrically connected to the second signal input end of the controller.

The drive device includes a drive motor and a motor support platform for installing the drive motor. The bottom of the motor support platform is fixedly connected to the base. The drive motor is installed on the top of the motor support platform, and the drive motor output The central axis of the shaft, the central axis of the transmission unit and the central axis of the test unit are coaxial.

During the test, fix the test piece on the rotating connecting shaft through a threaded connection, adjust the height of the lifting device to ensure that the axis of the test head coincides with the center line of the test piece, and then adjust the position of the slider so that the cylindrical test head is aligned with the test piece. The end faces are in contact and pressed tightly, and the slider is blocked by a baffle so that it will not move left along the center line. Start the motor to make the test piece rotate with the shaft. Through the linear strain generated by the resistance strain gauge located on the sleeve-type connecting shaft, the torque value is finally obtained by the strain gauge. The size of the pressure on the test piece can be obtained through the strain gauge pressure sensor. . According to the relationship between torque and friction, the friction force can be obtained through calculation. Then through the equivalent relationship between friction force, friction resistance coefficient and positive pressure, the friction resistance coefficient of the specimen can be obtained through calculation. size.

For the test of the friction coefficient of the bionic non-smooth surface, the cylindrical surface of the specimen is first processed by a lathe to form a non-smooth surface that meets the requirements, such as a surface with small protrusions, an oblique groove surface, etc., and the arc-shaped test The head is pressed tightly against the cylindrical side of the non-smooth surface of the test piece, so that the test surface has more contact area with the arc-shaped test head. The non-smooth surface test piece can be obtained through the strain gauge pressure sensor located on the arc-shaped test head. The magnitude of the pressure received, combined with the torque value measured by the torque test device, can finally obtain the friction resistance coefficient of the non-smooth surface.

The beneficial effects of the present invention are: the threaded connection between the shaft and the test piece is used for fixing the test piece, the fixing method is simple, and the structure of the entire experimental device is more compact. The threaded connection is in the opposite direction to the rotation of the motor. During the test, as the motor rotates, the connection between the specimen and the shaft becomes tighter, making this fixing method safer and more reliable. A hydraulically driven lifting device is introduced to adjust the upper and lower position of the test head, which avoids the disadvantages of slow and laborious manual adjustment. Limiting the left movement of the slider can be achieved simply by controlling the position of the baffle, which is simple and convenient to operate. The test head used to test pressure has two forms: cylindrical and arc type. It can not only be used to test the friction resistance coefficient of flat test pieces, but also can test the friction resistance coefficient of surfaces with different roughness and bionic non-smooth surfaces.

Description of the drawings

Figure 1 is a structural diagram of the torque testing device of the present invention.

Figure 2 is an enlarged partial view of the specimen fixed in the present invention.

Figure 3 is a structural diagram of the sleeve-type connecting shaft of the present invention.

Figure 4 is a side view of the sleeve-type connecting shaft of the present invention.

Figure 5 is a structural diagram of the pressure testing device of the present invention.

Figure 6 is a top view of the test board connection of the lifting device of the present invention.

Figure 7 is a plan view of the slide rail of the present invention.

Figure 8 is a side view of the slide rail of the present invention.

Figure 9 is a structural diagram of the test board of the present invention.

Figure 10 is a cross-sectional view of the non-smooth surface of the specimen of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Refer to the attached picture:

Embodiment 1 A friction resistance coefficient testing device based on hydraulic drive according to the present invention includes a torque testing device 1, a pressure testing device 2, a base 3 and a controller. The torque testing device 1 is fixedly connected to the base 3 , the pressure testing device 2 is slidingly connected to the base 3, and the sliding centerline of the pressure testing device 2 and the axis of the torque testing device 1 are in the same vertical plane; the signal output end of the torque testing device 1 . The signal output terminals of the pressure testing device 2 are electrically connected to the corresponding signal input terminals of the controller;

The torque testing device 1 includes a driving device 11 for providing rotational driving force, a transmission unit 12 for transmitting driving force, a test unit 13 for installing a test piece, and a torque testing unit 14 for measuring the torque of the transmission unit, The driving device 11 and the test unit 13 are coaxially installed on the base 3. The output shaft of the driving device 11 is fixedly connected to the test unit 13 through the transmission unit 12 to realize the transmission of driving force; The test end of the torque test unit 14 is attached to the surface of the transmission unit 12; the signal output end of the torque test unit 14 is electrically connected to the controller;

The pressure testing device 2 includes a bottom frame 21, a lifting device 22 for adjusting the height of the test end, and a pressure testing unit 23 for pressing on the surface of the test piece. The bottom frame 21 is slidingly connected to the base 3. The bottom of the lifting device 22 is fixedly connected to the chassis 21, and the pressure testing unit 23 is installed on the top of the lifting device 22; the free end of the pressure testing unit 23 is equipped with a test head for pressing on the surface of the test piece, The signal output end of the pressure testing unit 23 is electrically connected to the second signal input end of the controller.

The transmission unit 12 is a sleeve-type connecting shaft. The connecting shaft is axially provided with through holes penetrating both end surfaces of the connecting shaft. One end of the connecting shaft is keyed to the output shaft of the driving device 11; The other end is keyed to the installation shaft of the test unit 13; the center lines of the driving device 11, the transmission unit 12 and the test unit 13 coincide, ensuring that the force transmission is linear transmission.

The test unit 13 includes a cylinder 131, a rotating connecting shaft 132, a bearing end cover 133 and a bearing 134. The cylinder 131 is installed on the base 3 through a support frame 135. Both ends of the inner cavity of the cylinder 131 are equipped with The bearing 134 of the rotating connecting shaft 132 is horizontally supported. The two end surfaces of the cylinder 131 are respectively fixed with bearing end caps 133 for preventing the axial movement of the bearing 134; the two ends of the rotating connecting shaft 132 are connected from the corresponding bearing ends. The cover 133 passes through the central through hole, and the rotary connection shaft 132 is sealed and rotatably connected to the corresponding bearing end cap 133. The cylinder 131, the rotary connection shaft 132 and the bearing end cap 133 form a sealed chamber. The rotating pair; one end of the rotating connecting shaft 132 is keyed to one end of the connecting shaft, and the test piece 4 is installed on the other end.

The torque test unit 14 includes a strain gauge 141 and a plurality of resistive strain gauges 142. The resistive strain gauges 142 are attached to the outer wall of the connecting shaft. The signal output end of the resistive strain gauges 142 is connected to the resistive strain gauge 142 through a half-bridge circuit. The signal input terminal of the strain gauge 141 is electrically connected; the signal output terminal of the strain gauge 141 is electrically connected to the first signal input terminal of the controller.

The base frame 21 includes a slide rail 211, a slide block 212 and a block 213 for blocking the slide block. The slide rail 211 is laid on the base 3, and the slide rail 211 is fixedly connected to the base 3 to ensure smooth sliding. The centerline of the rail 211 is in the same vertical plane as the axis of the torque testing device 14; the slider 212 is inserted into the slide rail 211 through the opening at one end of the slide rail to ensure that the slider 212 slides along the centerline of the slide rail 211; The slide rail 211 has a strip slit for inserting the baffle 213 along its cross-sectional direction.

The pressure test unit 23 includes a test plate 231, a test head 232 and a strain gauge pressure sensor 233. One end of the test plate 231 is fixedly connected to the top of the lifting device 22, and the other end is equipped with a strain gauge pressure sensor 233, and each strain gauge The pressure sensor 233 is configured with a test head 232 for testing pressure; the signal output end of the strain gauge pressure sensor 233 is electrically connected to the second signal input end of the controller.

The lifting device 22 is a hydraulically driven lifting column, including an outer cylinder 221 and an inner core 222. The bottom of the outer cylinder 221 is fixedly connected to the slider 212 of the chassis 21; the lower end of the inner core 222 is inserted into the outer cylinder. 221 inner cavity and is slidingly connected thereto. The top of the inner core 222 is fixedly connected to the test plate 231 of the pressure testing unit 23; the sealed gap between the inner core 222 and the outer cylinder 221 is filled with lubricating fluid. The lifting column uses hydraulic oil as the driving medium. The lower part of the inner core of the lifting column is filled with hydraulic oil. The lifting and lowering of the lifting column is controlled through an external hydraulic power unit.

The test board 231 is divided into a circular disk for adjusting the horizontal rotation angle of the test head and a cuboid for installing the test head; the top of the circular disk of the test board 231 is embedded in the inner core 222 and is provided with a circle with a radius equivalent to the circular disk. The test plate 231 is placed in the inner core 222 of the lifting device 22 through the circular hole and the side mounting holes; test The right and lower sides of the cuboid end of the plate 231 are each connected to a strain gauge pressure sensor 233; the strain gauge pressure sensor on the right side is connected to a pressure column test head for measuring a test piece with a flat surface, and the lower side is connected to a strain gauge pressure sensor 233. The strain gauge pressure sensor is connected to an arc-shaped test head used to test the pressure of arc-shaped surfaces and bionic non-smooth surfaces; the signal output end of the strain gauge pressure sensor is connected to the second signal input of the controller Terminal electrical connection.

The driving device 11 includes a driving motor 111 and a motor supporting platform 112 for installing the driving motor. The bottom of the motor supporting platform 112 is fixedly connected to the base 3. The driving motor 111 is installed on the motor supporting platform 112. The top of the motor, and the central axis of the output shaft of the drive motor 111, the central axis of the transmission unit and the central axis of the test unit are coaxial.

During the test, the test piece 4 is fixed on the rotating connection shaft 132 through a threaded connection, the height of the lifting device 22 is adjusted to ensure that the axis of the test head 232 coincides with the center line of the test piece 4, and then the position of the slider 212 is adjusted to make the column The test head is in contact with the end surface of the test piece 4 and pressed tightly, and the slider 212 is blocked by the baffle 213 so that it will not move to the left along the center line. Start the drive motor 111, causing the specimen 4 to rotate together with the rotating connecting shaft 132. Through the linear strain generated by the resistive strain gauge 142 located on the sleeve-type connecting shaft 12, the torque value is finally obtained by the strain gauge 141, and the strain gauge pressure is The sensor 233 can obtain the pressure exerted on the test piece. According to the relationship between torque M [N·m] and friction force F [N], the size of friction force F = M/L can be obtained through calculation, and then through friction force F [N], friction resistance coefficient μ and positive pressure The equivalent relationship between N[N] is μ=F/N, and the friction resistance coefficient of the specimen can be obtained through calculation.

For the test of the friction coefficient of the bionic non-smooth surface, the cylindrical surface of specimen 4 is first processed by a lathe to form a non-smooth surface that meets the requirements, such as a surface with small protrusions, an oblique groove surface, etc., and the arc-shaped surface is The test head is pressed tightly against the cylindrical side of the non-smooth surface of the test piece, so that the test surface has more contact area with the arc-shaped test head. The non-smooth surface test can be obtained through the strain gauge pressure sensor located on the arc-shaped test head. The size of the pressure on the part, combined with the torque value measured by the torque testing device, can finally obtain the size of the friction resistance coefficient of the non-smooth surface.

Specifically, with reference to Figure 1 and Figure 2, the torque testing device is mainly used to test the magnitude of the torque experienced by the specimen. The driving motor 111 is fixed on the motor support platform 112 through bolts, and the motor support platform 112 and the base 3 are fixedly connected through bolts. The output shaft of the drive motor 111 is connected to the right side of the transmission unit 12 (ie, the sleeve-type connecting shaft) through a key, and the left side of the transmission unit 12 is connected to the rotating connection shaft 132 of the fixed specimen through the cooperation of the key and the keyway. The rotating connecting shaft 132 of the fixed specimen is fixed through the cylinder 131 and the bearing 134. The cylinder 131 and the support frame 135 are welded together, and the support frame 135 is fixed on the base 3 through bolt connection. The rotating connecting shaft 132 passes through the cylinder 131 along its axis. The rolling bearings 134 are sleeved on the shaft through the shoulders on the left and right sides of the rotating connecting shaft 132 and placed on both sides of the inside of the cylinder 131 to support the rotating connecting shaft 132 The two bearing end caps 133 are placed on the rotating connecting shaft 132 from both sides. The bearing end caps 133 and the cylinder 131 are connected by bolts. The bearing end caps 133 and the rotating connecting shaft 132 are connected by a seal. Ring 136 seals. Due to the existence of the motor support platform 112 and the support frame 135, it can be ensured that the axes of the drive motor 111 and the rotation connection shaft 132 are along the same direction. The left end of the rotating connecting shaft 132 has a threaded hole. Before the test piece 4 is tested, an external thread of appropriate length is machined along one end of the rotating connecting shaft 132 so that the rotating connecting shaft 132 and the testing piece 4 are threaded. This prevents the clamping device from loosening or causing the specimen to move axially. Using a threaded connection allows the test piece 4 to push the threaded hole on the rotating connecting shaft 132, so that the test piece will not move in the radial direction and is also restricted in the axial direction. During the test, as long as the drive motor 111 is kept The direction of rotation when the steering and test piece 4 is threaded with the rotating connecting shaft 132 is opposite. In this way, as the motor rotates, the fixation between the test piece 4 and the rotating connection shaft 132 will be stronger, safer and more reliable.

The method of measuring the torque of the sleeve-type connection axis is explained with reference to Figure 1 and Figure 3. There are two keyways on both sides of the transmission unit 12. The right side of the keyway is connected to the shaft of the driving motor 111, and the left side is connected to the rotating connection shaft 132 of the fixed specimen. A resistive strain gauge 142 is pasted on the transmission unit 12. The resistance strain gauge is pasted along the 45° direction of the transmission unit 12 axis and connected to the strain gauge 141 to form a half-bridge circuit. The strain reading of the strain gauge 141 can be obtained based on the half-bridge circuit principle. The connecting shaft is made of Q235 steel and the interfaces at both ends are designed. If carried out in accordance with the corresponding national standards, it can be ensured that the reading of the strain gauge 141 can reflect the real-time torque value.

Combining Figure 5, Figure 6 and Figure 7, the pressure testing device mainly includes: test plate 231, hydraulically driven lifting device 22, slider 212, baffle 213, and slide rail 211. The slide rail 211 is fixed on the base 3 through bolts. The slide block 212 is inserted into the slide rail 211 through the opening at one end of the slide rail 211. The slide rail needs to be of appropriate length so that the slide block 212 can slide left and right along the center line of the slide rail 211. . The center line of the slide rail 211 and the axis of the torque testing device are kept in the same vertical plane. The lifting device 22 is fixedly connected to the slider 212 through bolts. The lifting device 22 is composed of an outer cylinder 221 and an inner core 222. The inner core 222 is a solid cylinder. The gap between the outer cylinder 221 and the inner core 222 is filled with lubricating fluid for lubrication. The lift is driven by an external hydraulic power unit. The device 22 can realize the up and down movement of the inner core. The test plate 231 is placed through the hole in the inner core of the lifting device. The left side of the test plate 231 is a circular disk, and the right side is a rectangular parallelepiped with a square cross-section. There is a circular hole on the top of the inner core of the lifting device 22, the depth of the hole is slightly deeper than the thickness of the circular disk, and there is a strip slit on the right side of the inner core that is slightly wider than the width of the square cross-section of the test plate 231 cuboid. The test plate 231 is inserted into the inner core of the lifting device 22 through the circular hole and the strip slit, and the circular plate and the inner core are connected and fixed through bolts. The inner core and the test plate 231 are fixed as one body. As the inner core moves, the test plate 231 can move up and down, thus causing the vertical position of the test head to change. Prevent the test board from turning over due to force during the test. The right end of the rectangular parallelepiped of the test plate 231 is connected to a strain gauge pressure sensor 233 and then to a columnar test head 232 . The lower part of the cuboid near the right side is also connected to the strain gauge pressure sensor, and then connected to the arc-shaped test head 234. The cuboid is connected to the strain gauge pressure sensor 233 as well as the cylindrical test head 232 and the arc-shaped test head 234 through threads. During testing, the position of the test head cannot change, so the slider 212 cannot move to the left along the slide rail 211 . There is a slit along the cross section of the slide rail 211. When the slider 212 slides to an appropriate position, the baffle can be inserted into the slit, so that the left side of the slider 212 is restricted and cannot slide to the left. The vertical position of the test head can be adjusted by adjusting the lifting device 22 , and the horizontal position of the test head can be adjusted by adjusting the slider 212 . Combining the two functions can make the test head in the most appropriate position.

When testing, first adjust the pressure testing device to make the test head in the appropriate position: first adjust the lifting device 22 so that the column test head 232 is at the same height as the torque test device in the vertical direction, and then adjust the slider 212 to make the column test When the head 232 and the test piece 4 are fully contacted and pressed tightly, insert the baffle 213 into the gap in the slide rail 211 to prevent the slider 212 from moving to the left. After the adjustment is completed, start the driving motor 111, and rotate the rotating connecting shaft 132 of the fixed test piece through the sleeve-type connecting shaft 12. At this time, the test piece 4 also begins to rotate under the drive of the rotating connecting shaft 132, and the sleeve-type connecting shaft 132 rotates. The connecting shaft 12 is acted upon by torque, and the resistive strain gauge 142 pasted on the sleeve-type connecting shaft 12 will undergo linear strain, and the torque value at this time can be obtained through the strain gauge. The magnitude of the positive pressure on the surface of the specimen 4 can be obtained through the strain gauge pressure sensor 233 . The friction force can be obtained by using the relationship between torque and friction. Then through the relationship between friction force, positive pressure and friction resistance coefficient, the final friction resistance coefficient can be obtained by substituting the obtained data.

In the pressure testing device, the test head includes not only a cylindrical test head, but also an arc-shaped test head. Therefore, using this device can not only test the friction resistance coefficient of a specimen with a flat surface, but also test a bionic non-linear test piece with a flat surface. The friction coefficient of smooth surface. The test method of bionic non-smooth surface pressure is explained with reference to Figure 2, Figure 5 and Figure 10. Figure 10 The bionic non-smooth surface is a cross-sectional view of a non-smooth surface specimen with hemispherical protrusions. During the test, the position of the test plate 231 is adjusted so that the arc-shaped test head is in contact with the hemispherical protrusions on the cylindrical surface of the specimen 4. Surface 41 is in contact and compressed. When the specimen rotates stably with the axis, the pressure value on the bionic non-smooth surface at this time can be obtained through the strain gauge pressure sensor located on the arc-shaped test head, combined with the torque value obtained by the torque test device. , the surface friction coefficient of the non-smooth surface can be obtained through the relationship between friction force, positive pressure and friction coefficient.

The content described in the embodiments of this specification is only an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be considered to be limited to the specific forms stated in the embodiments. The protection scope of the present invention also includes those skilled in the art. Equivalent technical means that can be thought of based on the concept of the present invention.

Claims (5)

1. A friction resistance coefficient testing device based on hydraulic drive, characterized in that it includes a torque testing device, a pressure testing device, a base and a controller, the torque testing device is fixedly connected to the base, and the pressure testing device is connected to the base. The base is slidingly connected, and the sliding centerline of the pressure testing device and the axis of the torque testing device are in the same vertical plane; the signal output end of the torque testing device and the signal output end of the pressure testing device are respectively connected with The corresponding signal input terminal of the controller is electrically connected; The torque testing device includes a driving device for providing rotational driving force, a transmission unit for transmitting driving force, a test unit for installing a test piece, and a torque testing unit for measuring the torque of the transmission unit. The driving device, The test unit is coaxially installed on the base, and the output shaft of the driving device is fixedly connected to the test unit through a transmission unit to realize the transmission of driving force; the transmission unit is a sleeve-type connecting shaft, and the The connecting shaft is axially provided with through holes that penetrate both end surfaces of the connecting shaft. One end of the connecting shaft is keyed to the output shaft of the driving device; the other end of the connecting shaft is keyed to the installation shaft of the test unit; the driving device The center lines of the transmission unit and the test unit coincide to ensure that the force transmission is linear transmission; the torque test unit includes a strain gauge and a plurality of resistive strain gauges, and the resistive strain gauges are attached to the connecting shaft. The outer wall of the resistive strain gauge is pasted along the 45° direction of the axis of the transmission unit; the signal output end of the resistive strain gauge is electrically connected to the signal input end of the strain gauge through a half-bridge circuit; the signal output of the strain gauge The terminal is electrically connected to the first signal input terminal of the controller; the test terminal of the torque test unit is attached to the surface of the transmission unit; the signal output terminal of the torque test unit is electrically connected to the controller; The pressure testing device includes a bottom frame, a lifting device for adjusting the height of the test end, and a pressure testing unit for pressing on the surface of the test piece. The bottom frame is slidingly connected to the base, and the bottom of the lifting device is connected to the The bottom frame is fixed, and the pressure test unit is installed on the top of the lifting device; the free end of the pressure test unit is equipped with a test head for pressing on the surface of the test piece, and the signal output end of the pressure test unit is connected to the The second signal input terminal of the controller is electrically connected; The pressure test unit includes a test board, a test head and a strain gauge pressure sensor. One end of the test board is fixed to the top of the lifting device, and the other end is equipped with a strain gauge pressure sensor. Each strain gauge pressure sensor is configured with one for testing. pressure test head; the signal output end of the strain gauge pressure sensor is electrically connected to the second signal input end of the controller; the test board is divided into a circular disk for adjusting the horizontal rotation angle of the test head and a circular disk for adjusting the horizontal rotation angle of the test head. Install the cuboid of the test head; the circular disk of the test plate is embedded in the circular hole with the same radius as the circular disk provided on the top of the inner core and fixed by bolts. The cuboid of the test plate protrudes from the installation hole opened on the top side of the inner core. ; The test plate is placed in the inner core of the lifting device through the circular hole and the side mounting hole; the right and lower sides of the cuboid end of the test plate are connected to strain gauge pressure sensors; the strain gauge pressure sensor on the right side is connected to the strain gauge pressure sensor used to measure the test. The pressure column test head of the test piece with a flat surface is connected together, and the strain gauge pressure sensor on the lower side is connected with the arc test head used to test the pressure of the arc surface and the bionic non-smooth surface; so The signal output end of the strain gauge pressure sensor is electrically connected to the second signal input end of the controller. 2. A friction resistance coefficient testing device based on hydraulic drive according to claim 1, characterized in that: the test unit includes a cylinder, a rotating connecting shaft, a bearing end cover and a bearing, and the cylinder is installed on a support frame through a support frame. On the base, the two ends of the inner cavity of the cylinder are equipped with bearings for horizontally supporting the rotation connection shaft, and the two end surfaces of the cylinder are respectively fixed with bearing end caps for preventing the axial movement of the bearing; the rotation Both ends of the connecting shaft pass through the central through hole of the corresponding bearing end cover, and the rotating connecting shaft is sealed and rotationally connected with the corresponding bearing end cover. The cylinder, the rotating connecting shaft and the bearing end cover It forms a rotating pair with a sealed cavity; one end of the rotating connecting shaft is keyed to one end of the connecting shaft, and a test piece is installed on the other end. 3. A friction resistance coefficient testing device based on hydraulic drive according to claim 2, characterized in that: the chassis includes a slide rail, a slide block and a baffle for blocking the slide block, and the slide rail is laid on the On the base, the slide rail is fixedly connected to the base to ensure that the center line of the slide rail and the axis of the torque testing device are in the same vertical plane; the slide block is inserted into the slide rail through the opening at one end of the slide rail to ensure that the slide rail is The block slides along the center line of the slide rail; the slide rail has a strip slit for inserting the baffle along the direction of its cross section. 4. A friction resistance coefficient testing device based on hydraulic drive according to claim 3, characterized in that: the lifting device is a hydraulically driven lifting column, including an outer cylinder and an inner core, and the bottom of the outer cylinder and the bottom The slider of the frame is fixedly connected; the lower end of the inner core is inserted into the inner cavity of the outer cylinder and is slidingly connected with it; the top of the inner core is fixedly connected with the test plate of the pressure test unit; the inner core and The sealing gap between the outer cylinders is filled with lubricating fluid. 5. A friction resistance coefficient testing device based on hydraulic drive as claimed in claim 1, characterized in that: the drive device includes a drive motor and a motor support platform for installing the drive motor, and the bottom of the motor support platform Fixedly connected to the base, the drive motor is installed on the top of the motor support platform, and the central axis of the drive motor output shaft, the central axis of the transmission unit and the central axis of the test unit are coaxial.