Device and method for measuring dynamic friction coefficient of pivot rail

Abstract

The invention discloses a device and method for measuring the dynamic friction coefficient of a pivot rail, and the device enables an armature to move in a chamber under the condition that an electromagnetic emission device is not powered on, can effectively reduce the complex stress condition in the chamber in the actual emission process, obtains the friction force of solid-to-solid contact in the emission process in cooperation with the use of a strain gauge, and achieves the measurement of the dynamic friction coefficient of the pivot rail. And a theoretical basis is provided for research of an actual electromagnetic track launching system. According to the method for measuring the dynamic friction coefficient of the pivot rail, the motor is selected to pull the steel wire rope to enable the armature to move in the chamber, the wire outlet end of the steel wire rope is wound on the inclined column of the sensor, the tension of the steel wire rope can be displayed in real time through the sensor, and the tension is friction force according to the law of conservation of mechanics. According to the measuring method, the dynamic friction coefficient of the pivot rail can be measured by using the self-designed power traction auxiliary device and the strain gauge, the device is reasonable in structural design, the measuring method is simple, and the measuring result is reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring the dynamic friction coefficient between a pivot and a rail, and particularly to a device and a method for measuring the dynamic friction coefficient between a pivot and a rail. Background Technique

[0002] Electromagnetic launch technology converts electromagnetic energy into the kinetic energy required in the launch process. Compared with traditional chemical launches, it has the advantages of high launch efficiency, large initial kinetic energy, strong controllability, and high safety. The electromagnetic launch system mainly consists of a power supply, an armature, and rails. The two rails form a closed loop through the armature, generating a powerful Lorentz force to push the armature forward.

[0003] The dynamic friction coefficient between the pivot and the rail directly affects the frictional force suffered by the armature during its movement. The generation of frictional heat will cause the local temperature of the armature and the rail to rise, which not only affects the contact performance between the pivot and the rail but also affects the launch efficiency between the pivot and the rail. Therefore, it is very necessary to measure the dynamic friction coefficient between the pivot and the rail to extend the rail life and improve the system performance.

[0004] However, during the electromagnetic launch process, the complex electromagnetic-force-thermal coupling environment in the chamber makes it very difficult to directly measure the dynamic friction coefficient between the pivot and the rail, while the measurement of the dynamic friction coefficient between the pivot and the rail is very necessary. Summary of the Invention

[0005] To solve the deficiencies of the prior art, the present invention provides a device and a method for measuring the dynamic friction coefficient between a pivot and a rail. The device passes a steel wire rope on a tensile testing machine through the throat of the armature, places the armature at the muzzle in the rail launcher, and pulls the armature to move through the tensile testing machine to realize the non-powered movement of the armature and make the armature move in the electromagnetic launcher. Strain gauges are installed on the surface of the armature, which can reflect the strain of the armature in real time during movement, that is, it can reflect the pressure suffered by the armature during movement in real time. Through the mechanical sensor installed on the triangular support at the working platform and installing a display screen, the tensile force suffered by the armature can be displayed in real time. The tensile testing machine controls the armature to move at a constant speed, and through the basic mechanical equation, the dynamic friction coefficient between the pivot and the rail during the movement of the armature can be calculated.

[0006] To achieve the above object, the present invention provides the following technical solution: Design a device for measuring the dynamic friction coefficient between a pivot and a rail, which is characterized in that the device consists of a workbench, a triangular support, a sensor device, and a tensile testing machine;

[0007] The tensile testing machine is fixed to the left side of the workbench by screws through the mounting bracket in the front-back direction; the tensile testing machine includes a motor, the output shaft of the motor is horizontally oriented towards the front side of the workbench, and the drum is fixedly sleeved on the output shaft of the motor; a steel wire rope is wound around the outer wall surface of the drum, and the fixed end of the steel wire rope is located on the drum. The drum rotates as the motor operates, so as to retract or release the steel wire rope;

[0008] The bottom of the triangular bracket is fixed to the right side of the workbench by screws; the upper part of the triangular bracket is a square rod that forms an acute angle with the top surface of the workbench, and the top surface of the square rod faces one side of the workbench; the position of the left side surface of the square rod is aligned with the position of the steel wire rope on the drum. The top surface of the square rod is orthogonal to both its left side surface and right side surface. The sensor device is fixed on the top surface of the square rod; the sensor device includes a sensor inclined column connecting plate, a sensor connecting plate, a pressure sensor, a bearing seat connecting plate, a bearing seat, and a pulley. The sensor inclined column connecting plate is welded to the top surface of the square rod of the triangular bracket. The sensor connecting plate is fixed to the top surface of the sensor inclined column connecting plate by screws. The lower end of the pressure sensor is installed on the sensor connecting plate. The lower surface of the bearing seat connecting plate is connected to the upper end of the pressure sensor. The bearing seat is installed on the top surface of the bearing seat connecting plate by screws. A pulley is installed in the middle of the bearing seat through a shaft and a bearing. A groove is provided in the middle of the outer side surface of the pulley for placing the steel wire rope; the axis of the shaft of the pulley is parallel and coplanar with the axis of the output shaft of the motor;

[0009] The fixed end of the steel wire rope on the drum is fixed to the drum, its movable end is pulled upwards and wound around the pulley of the sensor device, then pulled to the right, passes through the breech of the electromagnetic emission device and reaches the muzzle position, and is fixed to the throat of the armature;

[0010] The height of the steel wire rope on the pulley is the same as the height of the steel wire rope at the throat of the armature, and the steel wire rope between these two points is in a horizontal state and parallel to the running track of the armature.

[0011] Furthermore, the present invention designs a method for measuring the dynamic friction coefficient of the pivot track, which is characterized in that this method uses the above-mentioned device and the following steps:

[0012] Step 1: Fix the electromagnetic emission device on the right side of the workbench so that the height of the top surface of the workbench is the same as the height of the platform of the electromagnetic emission device. The running track of the armature of the electromagnetic emission device is horizontally arranged in the left-right direction, and the end of the track close to the workbench is the breech, and the end far from the workbench is the muzzle. The armature is placed at the muzzle position. In the case of no driving current, the armature remains stationary; the running track of the armature is arranged on the front and rear sides of the armature, and the contact surfaces between the front and rear sides of the armature and the corresponding side tracks are in an unevenly fitting state. Bond the strain gauges to the top surface of the armature;

[0013] Step 2: Turn on the motor to make the wire rope pull the armature to move uniformly from the muzzle position to the breech position.

[0014] Step 3: Obtain the magnitude of the force F received by the pressure sensor during the process of the armature moving uniformly from the muzzle position to the breech position, and the strain of the strain gauge on the top surface of the armature; obtain the pressure F received by the armature during the movement according to the strain of the strain gauge. N , since the sensor inclined column and the wire rope form an angle θ, calculate the pivot-rail friction coefficient during the entire movement of the armature through the following formula;

[0015]

[0016] That is, the measurement of the dynamic friction coefficient between the pivot and the rail is realized.

[0017] Compared with the existing technology, the beneficial effects of the present invention are as follows: The device designed for measuring the dynamic friction coefficient between the pivot and the rail in the present invention can make the armature move in the chamber when the electromagnetic launch device is not powered on, which can effectively reduce the complex force conditions in the chamber during the actual launch process. Combined with the use of strain gauges, the friction force of solid-solid contact during the launch process is obtained, providing a theoretical basis for the research of the actual electromagnetic rail launch system. The method designed for measuring the dynamic friction coefficient between the pivot and the rail in the present invention uses a motor to tow a wire rope to make the armature move in the chamber. The wire rope outlet end is wound around the sensor inclined column, and the sensor can display the magnitude of the wire rope tension in real time. According to the law of conservation of mechanics, the tension is the friction force. The measurement method of the present invention can realize the measurement of the dynamic friction coefficient between the pivot and the rail by using the self-designed power traction auxiliary device and strain gauges. The device structure is reasonably designed, the measurement method is simple, and the measurement result is reliable. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of an embodiment of a device for measuring the dynamic friction coefficient between the pivot and the rail in the present invention.

[0019] Figure 2 It is a schematic structural diagram of a workbench of an embodiment of a device for measuring the dynamic friction coefficient between the pivot and the rail in the present invention.

[0020] Figure 3 It is a schematic structural diagram of a triangular bracket of an embodiment of a device for measuring the dynamic friction coefficient between the pivot and the rail in the present invention.

[0021] Figure 4 It is a schematic structural diagram of a sensor of an embodiment of a device for measuring the dynamic friction coefficient between the pivot and the rail in the present invention.

[0022] Figure 5 It is a schematic structural diagram of a tensile testing machine of an embodiment of a device for measuring the dynamic friction coefficient between the pivot and the rail in the present invention.

[0023] In the attached drawings:

[0024] 1. Workbench; 101. First workbench longitudinal column; 102. Second workbench longitudinal column; 103. Third workbench longitudinal column; 104. Fourth workbench longitudinal column; 105. Fifth workbench longitudinal column; 106. Workbench footrest; 107. First workbench upright column; 108. Second workbench upright column; 109. Third workbench upright column; 110. Fourth workbench upright column; 111. First workbench cross column; 112. Second workbench cross column; 113. Third workbench cross column; 114. Fourth workbench cross column; 115. First workbench connecting column; 116. Second workbench connecting column; 117. Third workbench connecting column; 118. Fourth workbench connecting column; 119. First connecting plate; 120. Second connecting plate; 121. Third connecting plate; 122. Fourth connecting plate; 123. Workbench support column

[0025] 2. Triangular bracket; 201. Sensor inclined column; 202. Sensor upright column; 203. Angle steel; 204. Connecting column; 205. Connecting upright column

[0026] 3. Sensor device; 301. Pulley; 302. Bearing seat; 303. Bearing seat connecting plate; 304. Pressure sensor; 305. Sensor connecting plate; 306. Sensor inclined column connecting plate

[0027] 4. Tensile testing machine; 401. Motor; 402. First fixing bolt; 403. Second fixing bolt; 404. Drum; 405. Third fixing bolt Detailed implementation manners

[0028] The following are specific embodiments of the present invention. The specific embodiments are only used for further detailed description of the present invention and do not limit the protection scope of the claims of the application

[0029] The present invention provides a device for measuring the dynamic friction coefficient of a pivot rail. The device is composed of a workbench 1, a triangular bracket 2, a sensor device 3, and a tensile testing machine 4

[0030] The tensile testing machine 4 is fixed to the left side of the workbench 1 in the front-rear direction by screws through a mounting bracket; the tensile testing machine 4 includes a motor 401, the output shaft of the motor 401 faces the front side of the workbench 1 horizontally, and a drum 404 is fixedly sleeved on the output shaft of the motor 401; a steel wire rope is wound on the outer wall surface of the drum 404, and the fixed end of the steel wire rope is located on the drum 404. The drum 404 rotates with the operation of the motor, so that the steel wire rope is retracted or released

[0031] The motor 401 is a CD-K1 all-aluminum shell motor, the speed can be 14 m / min, the voltage is 220 V, and the motor power is 3 KW

[0032] The bottom of the triangular support 2 is fixed to the right side of the workbench 1 by screws; the upper part of the triangular support 2 is a square rod that forms an acute angle with the top surface of the workbench 1, and the top surface of this square rod faces one side of the workbench 1; the position of the left side surface of this square rod is directly opposite to the position of the steel wire rope on the winding drum 404, and the top surface of this square rod is orthogonal to both its left and right side surfaces. The sensor device 3 is fixed on the top surface of this square rod. The sensor device 3 includes a sensor inclined column connecting plate 306, a sensor connecting plate 305, a pressure sensor 304, a bearing seat connecting plate 303, a bearing seat 302, and a pulley 301. The sensor inclined column connecting plate 306 is welded to the top surface of the square rod of the triangular support 2. The sensor connecting plate 305 is fixed to the top surface of the sensor inclined column connecting plate 306 by screws. The lower end of the pressure sensor 304 is installed on the sensor connecting plate 305. The lower surface of the bearing seat connecting plate 303 is connected to the upper end of the pressure sensor 304. The bearing seat 302 is installed on the top surface of the bearing seat connecting plate 303 by screws. A pulley 301 is installed in the middle of the bearing seat 302 through a shaft and bearings. A groove is provided in the middle of the outer side surface of the pulley 301 for placing the steel wire rope. The axis of the shaft of the pulley 301 is parallel and coplanar with the axis of the output shaft of the motor 401.

[0033] The fixed end of the steel wire rope on the winding drum 404 is fixed to the winding drum 404. Its movable end is pulled upward and wound around the pulley 301 of the sensor device 3, then pulled to the right, passes through the breech of the electromagnetic emission device and reaches the muzzle position, and is fixed to the throat of the armature.

[0034] To reduce the measurement error, the height of the steel wire rope on the pulley 301 of the device should be set to be the same as the height of the steel wire rope at the throat of the armature, and the steel wire rope between these two points should be in a horizontal state and parallel to the running track of the armature.

[0035] The pressure sensor 304 is a clam-shell transmission high-precision planar tension weighing circular weight pressure sensor with a diameter of 2.5 cm and a range of 5000 N.

[0036] As an embodiment, the workbench 1 is of a frame structure, specifically including a first workbench column 107, a second workbench column 108, a third workbench column 109, a fourth workbench column 110, a fourth workbench longitudinal column 104, a fifth workbench longitudinal column 105, a third workbench cross column 113, a fourth workbench cross column 114, a first workbench cross column 111, a second workbench cross column 112, a first workbench longitudinal column 101, a second workbench longitudinal column 102, a third workbench longitudinal column 103, and a workbench support column 123. The first workbench column 107, the second workbench column 108, the third workbench column 109, and the fourth workbench column 110 are vertically arranged at the four vertices of a square. The third workbench cross column 113, the fifth workbench longitudinal column 105, the fourth workbench cross column 114, and the fourth workbench longitudinal column 104 are respectively fixedly connected at the same height positions at the lower parts between two adjacent columns, and the lower parts of the first workbench column 107, the second workbench column 108, the third workbench column 109, and the fourth workbench column 110 are fixedly connected into a whole.

[0037] The first workbench cross column 111 is horizontally fixed at the tops of the first workbench column 107 and the second workbench column 108 in the left - right direction. The second workbench cross column 112 is horizontally fixed at the tops of the third workbench column 109 and the fourth workbench column 110 in the left - right direction, and the first workbench cross column 111 and the second workbench cross column 112 are parallel and coplanar. The first workbench longitudinal column 101 is fixed in the front - back direction on the left side between the first workbench cross column 111 and the second workbench cross column 112. The second workbench longitudinal column 102 is fixed in the front - back direction in the middle between the first workbench cross column 111 and the second workbench cross column 112. The third workbench longitudinal column 103 is fixed in the front - back direction at the right end between the first workbench cross column 111 and the second workbench cross column 112. The workbench support column 123 is fixed in the left - right direction in the middle between the second workbench longitudinal column 102 and the third workbench longitudinal column 103. The first workbench longitudinal column 101, the second workbench longitudinal column 102, and the third workbench longitudinal column 103 are parallel and their top surfaces are coplanar. The workbench support column 123 is parallel to the first workbench cross column 111 and is orthogonal to the second workbench longitudinal column 102 and the third workbench longitudinal column 103. Threaded holes are provided on the top surfaces of the first workbench longitudinal column 101, the second workbench longitudinal column 102, and the workbench support column 123. The threaded holes on the first workbench longitudinal column 101 and the second workbench longitudinal column 102 are used for fixedly installing a tensile machine 4, and the threaded hole of the workbench support column 123 is used for fixedly installing a triangular bracket 2.

[0038] Furthermore, workbench foot pads 106 are provided at the bottom surfaces of the first workbench column 107, the second workbench column 108, the third workbench column 109, and the fourth workbench column 110.

[0039] Furthermore, the workbench 1 further includes a first workbench connecting post 115, a second workbench connecting post 116, a third workbench connecting post 117, a fourth workbench connecting post 118, a first connecting plate 119, a second connecting plate 120, a third connecting plate 121, and a fourth connecting plate 122. The first workbench connecting post 115 and the second workbench connecting post 116 are horizontally connected to the right side surfaces of the first workbench cross post 111 and the second workbench cross post 112 in the left-right direction. The third workbench connecting post 117 and the fourth workbench connecting post 118 are horizontally connected to the right side surfaces of the second workbench upright post 108 and the third workbench upright post 109 in the left-right direction. The positions of these four in the horizontal direction are respectively directly opposite to the first workbench cross post 111, the second workbench cross post 112, the third workbench cross post 113, and the fourth workbench cross post 114. The first connecting plate 119, the second connecting plate 120, the third connecting plate 121, and the fourth connecting plate 122 are respectively fixed to the outer side surfaces of the first workbench connecting post 115, the second workbench connecting post 116, the third workbench connecting post 117, and the fourth workbench connecting post 118 by screws, for fixedly connecting the electromagnetic emission device equipped with the pivot rail system, facilitating the test operation, and enhancing the structural stability of the device at the same time.

[0040] As an embodiment, the triangular bracket 2 specifically includes an angle steel 203, a sensor upright post 202, a connecting upright post 205, a connecting post 204, and a sensor inclined post 201. The angle steel 203 presents a "convex" shape. A sensor upright post 202 is welded to its left end, and a connecting upright post 205 is welded to its right end. The sensor upright post 202 opens a small hole at the same height as the top surface of the connecting upright post 205 on its right side surface. The left side surface of the connecting post 204 is fixedly connected to the right side surface of the sensor upright post 202 through the above-mentioned small hole. The right side of the bottom surface of the connecting post 204 is welded to the top of the connecting upright post 205.

[0041] The top surface of the sensor upright post 202 is an inclined surface. The sensor inclined post 201 is a square rod, and its bottom surface is an inclined surface. The bottom surface of the sensor inclined post 201 is welded to the right side of the top surface of the connecting post 204, and the top surface of the sensor upright post 202 is welded to the left side surface of the sensor inclined post 201. The lower part of the angle steel 203 is fixed to the right side of the workbench 1 by screws.

[0042] Furthermore, the present invention provides a method for measuring the dynamic friction coefficient of a pivot rail, which is characterized in that the method uses the above-mentioned device and the following steps:

[0043] Step 1: Fix the electromagnetic launching device on the right side of the workbench so that the top surface height of the workbench is the same as the platform height of the electromagnetic launching device. The running track of the armature of the electromagnetic launching device is horizontally arranged in the left-right direction, and the end of the track close to the workbench is the breech, and the end far from the workbench is the muzzle. The armature is placed at the muzzle position, and in the absence of driving current, the armature remains stationary. The running track of the armature is arranged on the front and rear sides of the armature, and the contact surfaces between the front and rear sides of the armature and the corresponding side tracks are in an unevenly engaged state. Bond the strain gauge on the top surface of the armature.

[0044] Step 2: Start the motor 401 to make the steel wire rope pull the armature to move uniformly from the muzzle position to the breech position.

[0045] Step 3: Obtain the magnitude of the force F received by the pressure sensor 304 during the process of the armature moving uniformly from the muzzle position to the breech position, and the strain of the strain gauge on the top surface of the armature. Obtain the pressure F received by the armature during the movement according to the strain of the strain gauge. N , since the sensor inclined column and the steel wire rope form an angle θ, calculate the pivot-rail friction coefficient during the entire movement process of the armature through the following formula.

[0046]

[0047] That is, the measurement of the dynamic friction coefficient between the pivot and the rail is realized.

[0048] During the movement of the armature, the tensile force on the steel wire rope acts on the pressure sensor 304. The pressure sensor 304 is connected to an external display screen or a host computer, and the magnitude of the force F received by the pressure sensor 304 can be obtained in real time. Since the sensor inclined column and the steel wire rope form an angle θ (as an embodiment, the angle is 45°), the tensile force received by the armature during the movement is cosθ times F. A strain gauge is installed on the top surface of the armature, and during the movement of the armature, the strain gauge can reflect the strain of the armature (i.e., the deformation amount) in real time. The relationship between the strain of the armature and the pressure received by the armature can be obtained through the strain experiment before testing, that is, the pressure F received by the armature during the movement can be reflected in real time. N .

[0049] The parts not described in the present invention are applicable to the prior art.

Claims

1. A device for measuring the dynamic friction coefficient of a pivot track, characterized in that The device consists of a workbench, a triangular bracket, a sensor device, and a tensile testing machine; The tensile testing machine is fixed to the left side of the workbench in the front-back direction by screws through a mounting bracket; the tensile testing machine includes a motor, the output shaft of the motor is horizontally oriented towards the front side of the workbench, and a drum is fixedly sleeved on the output shaft of the motor; a steel wire rope is wound around the outer wall surface of the drum, and the fixed end of the steel wire rope is located on the drum. The drum rotates with the operation of the motor, so as to retract or release the steel wire rope; The bottom of the triangular bracket is fixed to the right side of the workbench by screws; the upper part of the triangular bracket is a square rod forming an acute angle with the top surface of the workbench, and the top surface of the square rod faces the side of the workbench; the position of the left side surface of the square rod is directly opposite to the position of the steel wire rope on the drum. The top surface of the square rod is orthogonal to both its left side surface and right side surface. The sensor device is fixed on the top surface of the square rod; the sensor device includes a sensor inclined column connecting plate, a sensor connecting plate, a pressure sensor, a bearing seat connecting plate, a bearing seat, and a pulley. The sensor inclined column connecting plate is welded to the top surface of the square rod of the triangular bracket, the sensor connecting plate is fixed to the top surface of the sensor inclined column connecting plate by screws, the lower end of the pressure sensor is installed on the sensor connecting plate, the lower surface of the bearing seat connecting plate is connected to the upper end of the pressure sensor, the bearing seat is installed on the top surface of the bearing seat connecting plate by screws, a pulley is installed on the bearing seat through a shaft and a bearing in the middle, and a groove is provided in the middle of the outer side surface of the pulley for placing the steel wire rope; the axis of the shaft of the pulley is parallel and coplanar with the axis of the output shaft of the motor; The fixed end of the steel wire rope on the drum is fixed to the drum, its movable end is pulled upwards and wound around the pulley of the sensor device, then pulled to the right, passes through the breech of the electromagnetic emission device and reaches the muzzle position, and is fixed to the throat of the armature; The height of the steel wire rope on the pulley is the same as the height of the steel wire rope at the throat of the armature, and the steel wire rope between these two points is in a horizontal state and parallel to the running track of the armature.

2. The device for measuring the dynamic friction coefficient of a pivot rail according to claim 1, wherein The workbench is of a frame structure, specifically including a first workbench column, a second workbench column, a third workbench column, a fourth workbench column, a fourth workbench longitudinal column, a fifth workbench longitudinal column, a third workbench cross column, a fourth workbench cross column, a first workbench cross column, a second workbench cross column, a first workbench longitudinal column, a second workbench longitudinal column, a third workbench longitudinal column, and a workbench support; the first workbench column, the second workbench column, the third workbench column, and the fourth workbench column are vertically arranged at the four vertices of a square. The third workbench cross column, the fifth workbench longitudinal column, the fourth workbench cross column, and the fourth workbench longitudinal column are respectively fixedly connected at the same height at the lower part between two adjacent columns, and the lower parts of the first workbench column, the second workbench column, the third workbench column, and the fourth workbench column are fixedly connected into a whole; The horizontal cross-column of the first workbench is fixed horizontally in the left-right direction at the tops of the first workbench column and the second workbench column. The horizontal cross-column of the second workbench is fixed horizontally in the left-right direction at the tops of the third workbench column and the fourth workbench column. And the horizontal cross-column of the first workbench and the horizontal cross-column of the second workbench are parallel and coplanar. The vertical column of the first workbench is fixed in the front-back direction on the left side between the horizontal cross-column of the first workbench and the horizontal cross-column of the second workbench. The vertical column of the second workbench is fixed in the front-back direction in the middle between the horizontal cross-column of the first workbench and the horizontal cross-column of the second workbench. The vertical column of the third workbench is fixed in the front-back direction at the right end between the horizontal cross-column of the first workbench and the horizontal cross-column of the second workbench. The workbench support column is fixed in the left-right direction in the middle between the vertical column of the second workbench and the vertical column of the third workbench. The vertical column of the first workbench, the vertical column of the second workbench and the vertical column of the third workbench are parallel and their top surfaces are coplanar. The workbench support column is parallel to the horizontal cross-column of the first workbench and orthogonal to the vertical column of the second workbench and the vertical column of the third workbench. Threaded holes are provided on the top surfaces of the vertical column of the first workbench, the vertical column of the second workbench and the workbench support column. The threaded holes on the vertical column of the first workbench and the vertical column of the second workbench are used for fixedly installing a tensile testing machine. The threaded hole of the workbench support column is used for fixedly installing a triangular bracket.

3. The device for measuring the dynamic friction coefficient of a pivot rail according to claim 2, characterized in that, Workbench pads are provided at the bottom surfaces of the first workbench column, the second workbench column, the third workbench column and the fourth workbench column.

4. A device for measuring the dynamic friction coefficient of a pivot rail according to claim 2, characterized in that, The workbench further includes a first workbench connecting column, a second workbench connecting column, a third workbench connecting column, a fourth workbench connecting column, a first connecting plate, a second connecting plate, a third connecting plate and a fourth connecting plate. The first workbench connecting column and the second workbench connecting column are horizontally connected in the left-right direction on the right side surfaces of the horizontal cross-column of the first workbench and the horizontal cross-column of the second workbench. The third workbench connecting column and the fourth workbench connecting column are horizontally connected in the left-right direction on the right side surfaces of the second workbench column and the third workbench column. The positions of these four in the horizontal direction are respectively corresponding and facing the horizontal cross-column of the first workbench, the horizontal cross-column of the second workbench, the horizontal cross-column of the third workbench and the horizontal cross-column of the fourth workbench. The first connecting plate, the second connecting plate, the third connecting plate and the fourth connecting plate are respectively fixedly connected to the outer side surfaces of the first workbench connecting column, the second workbench connecting column, the third workbench connecting column and the fourth workbench connecting column by screws, and are used for fixedly connecting an electromagnetic launching device equipped with a pivot rail system.

5. The device for measuring the dynamic friction coefficient of a pivot rail according to claim 1, wherein, The triangular bracket specifically includes an angle steel, a sensor column, a connecting column, a connecting post and a sensor inclined column. The angle steel presents a "convex" shape. A sensor column is welded to its left end, and a connecting column is welded to its right end. A small hole is opened on the right side surface of the sensor column at the same height as the top surface of the connecting column. The left side surface of the connecting post is fixedly connected to the right side surface of the sensor column through the above-mentioned small hole. The right side of the bottom surface of the connecting post is welded to the top of the connecting column. The top surface of the sensor column is an inclined surface. The sensor inclined column is a square rod, and its bottom surface is an inclined surface. The bottom surface of the sensor inclined column is welded to the right side of the top surface of the connecting post, and the top surface of the sensor column is welded to the left side surface of the sensor inclined column. The lower part of the angle steel is fixed to the right side of the workbench by screws.

6. The device for measuring the dynamic friction coefficient of a pivot rail according to claim 1, characterized in that, The motor is a CD-K1 fully aluminum shell motor, with a speed of 14 m / min, a voltage of 220 V, and a motor power of 3 KW.

7. The device for measuring the dynamic friction coefficient of a pivot rail according to claim 1, characterized in that, The pressure sensor is a clam-shell transmission high-precision planar tension weighing circular weight pressure sensor with a diameter of 2.5 cm and a range of 5000 N.

8. A method for measuring the dynamic friction coefficient of a pivot rail, characterized in that, This method uses the device described in any one of claims 1-7 and the following steps: Step 1: Fix the electromagnetic emission device on the right side of the workbench so that the top surface height of the workbench is the same as the platform height of the electromagnetic emission device. The running track of the armature of the electromagnetic emission device is horizontally arranged in the left-right direction, and the end of the track close to the workbench is the breech end, and the end far from the workbench is the muzzle. The armature is placed at the muzzle position. In the absence of a driving current, the armature remains stationary; the running track of the armature is arranged on the front and rear sides of the armature, and the contact surfaces between the front and rear sides of the armature and the corresponding side tracks are in an unevenly engaged state. Bond the strain gauge to the top surface of the armature. Step 2: Start the motor to make the steel wire rope pull the armature to move uniformly from the muzzle position to the breech end position. Step 3: Obtain the magnitude of the force F received by the pressure sensor during the process of the armature moving uniformly from the muzzle position to the breech position, and the strain of the strain gauge on the top surface of the armature; obtain the pressure F received by the armature during the movement according to the strain of the strain gauge N , since the sensor inclined column and the wire rope form an angle θ, calculate the pivot-rail friction coefficient during the entire movement process of the armature through the following formula; That is, the measurement of the dynamic friction coefficient between the pivot and the track is realized.

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