Collision recovery coefficient measuring device and method

Abstract

The invention discloses a collision recovery coefficient measuring device and method, and relates to the field of mechanical engineering, the collision recovery coefficient measuring device comprises an ejector, an electromagnet, a movable block, a static block and a base, and the static block is connected with the base through a screw; the electromagnet comprises a fixing structure and an armature, one end of the fixing structure is connected with the base, the other end of the fixing structure is connected with the ejector, the armature slides relative to the fixing structure in the direction close to or away from the static block, the end, close to the static block, of the armature is connected with the movable block, and the other end directly faces the output end of the ejector. The fixing structure is used for generating magnetic steel force towards the ejector or the static block on the armature according to the position of the armature; and the output end of the ejector is used for applying ejection force to the armature. The device is simple and compact in overall structure, low in development cost, easy to test the collision recovery coefficient according to the actual collision condition, and simple and convenient in test operation and calculation.

Description

Technical Field

[0001] The invention relates to a device and method for measuring a collision restitution coefficient, and belongs to the field of mechanical engineering. Background Art

[0002] Collision is a common phenomenon in mechanical systems. It is a form of interaction between parts. It is characterized by high intensity, short duration, and complex mechanism. In engineering, people are usually concerned with the change in the motion state of an object before and after a collision, and the collision restitution coefficient is an important parameter that characterizes the change in the motion state before and after a collision. Domestic and foreign researchers have conducted extensive research on the collision restitution coefficient and proposed a variety of collision model assumptions and calculation formulas. However, most of these studies are theoretical studies, and the proposed models and formulas are usually complex and not very applicable to general engineering problems.

[0003] In the prior art, there are few studies on the experimental measurement of the collision recovery coefficient. The more common method is to use an acceleration system to eject the collision body and collide with the collision body, and use a high-speed camera to record the collision process, and then convert the recorded data into the speed before and after the collision, so as to calculate the collision recovery coefficient. This test method usually requires a complex test system, generally including: gas tanks, high-pressure air chambers, airflow triggers, collision body guide rails, high-speed cameras, etc. Due to the limitation of the frame rate of high-speed cameras, the test accuracy is usually not very high, and this method is mainly suitable for collisions between larger collision bodies, and is not suitable for collisions between smaller collision bodies. Summary of the invention

[0004] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and to provide a device and method for measuring the coefficient of collision recovery. The device has a simple and compact overall structure, low development cost, is easy to test the coefficient of collision recovery according to actual collision conditions, and has simple test operation and calculation.

[0005] The technical solutions provided by this application are as follows:

[0006] A collision restitution coefficient measuring device comprises an ejector, an electromagnet, a moving block, a static block and a base, wherein the static block is connected to the base via screws; the electromagnet comprises a fixing structure and an armature, wherein one end of the fixing structure is connected to the base and the other end is connected to the ejector, the armature slides relative to the fixing structure along a direction approaching or moving away from the static block, one end of the armature close to the static block is connected to the moving block and the other end faces an output end of the ejector; the fixing structure is used to generate a magnetic steel force on the armature in the direction of the ejector or the static block according to the position of the armature; and the output end of the ejector is used to apply an ejection force to the armature.

[0007] The ejector comprises a fixed sleeve, a rotating sleeve, a lower end cover, an upper end cover, a spring, an ejection rod, a draw hook, a butterfly nut and a draw rope; the lower end cover is connected to one end of the fixed sleeve, the other end of the fixed sleeve is connected to the rotating sleeve through a fine thread, the rotating sleeve is connected to the upper end cover, and the electromagnet is connected to the lower end cover; the ejection rod passes through the fixed sleeve and the rotating sleeve, and is slidably connected to the fixed sleeve and the rotating sleeve along the axis direction of the rotating sleeve, and one end of the armature is directly opposite to the end of the ejection rod; the spring is connected between the ejection rod and the electromagnet so that the ejection rod applies an ejection force to the armature; the butterfly nut is rotatably connected to the upper end cover, and the draw hook is threadedly connected to the butterfly nut; the moving direction of the ejection rod is along the axis direction of the fixed sleeve, and the draw rope is connected between the draw hook and the ejection rod; by rotating the butterfly nut, the draw hook is driven to move, and the draw hook drives the ejection rod to move to contact with the fixed sleeve. The upper end of the ejection rod is connected to the draw hook through a draw rope, and the draw hook is threadedly connected to the butterfly nut. When the butterfly nut is tightened, the draw hook moves upward, pulling the ejection rod through the draw rope to squeeze the spring. When the draw rope is cut, the spring applies an ejection force to the ejection rod, causing the ejection rod to push the armature to move toward the static block.

[0008] The upper end cover is provided with a rectangular limiting groove, and the hook end of the draw hook is a flat structure, and the flat structure of the draw hook matches with the rectangular limiting groove of the upper end cover.

[0009] The rotating sleeve is provided with a rectangular limiting groove, and the ejection rod has a flat structural part, which is matched with the rectangular limiting groove.

[0010] The inner wall surface of the fixed sleeve is provided with an annular surface E, and the outer wall surface is provided with an annular surface F, and the annular surface E and the annular surface F are on the same plane; the interior of the rotating sleeve is provided with an annular surface M, and the outer wall surface is provided with an annular surface N, and the annular surface M and the annular surface N are on the same plane; the ejection rod is provided with a convex ring, the annular surface E is located on the side of the convex ring away from the moving block and is used to limit the moving stroke of the convex ring, the spring is in contact with the side of the convex ring away from the moving block, and the spring is in contact with the annular surface M.

[0011] The fixed structure comprises an upper stopper, a lower stopper, a jacket, a magnet, an upper coil, a lower coil and a frame; the upper stopper and the lower stopper are respectively connected to the two ends of the jacket, the upper stopper is used to connect the catapult, and the lower stopper is used to connect the base; the jacket is a cylinder with openings at both ends, the framework is located in the jacket, and the magnet is bonded to the middle part of the outside of the framework; the upper coil and the lower coil are respectively wound on the framework and located on both sides of the magnet; the armature is located in the framework, and the two ends of the armature pass through the upper stopper and the lower stopper respectively; the magnet is a ring-shaped permanent magnetic material, and its two poles are respectively located on the cylindrical surface in contact with the framework and the cylindrical surface in contact with the jacket; the upper stopper, the lower stopper, the jacket and the armature are soft magnetic materials.

[0012] When the ejection rod is pulled up to contact with the fixed sleeve, there is a gap Δ between the ejection rod and the lower end cover. This position is taken as the displacement zero point. If the armature is gradually moved toward the lower stop iron until the magnetic steel force is zero, the displacement is recorded as δ0, Δ<δ0.

[0013] A method for measuring a collision restitution coefficient, measuring according to any of the above-mentioned collision restitution coefficient measuring devices, comprising:

[0014] S1: Calculate the work W done by the magnetic force when the armature moves from the position where the magnetic force is zero to the position where the moving block and the static block just touch each other. c ;

[0015] S2: Obtain the relationship between the compression force F on the spring and the spring length x;

[0016] S3: Measure the masses of the armature, movable block and ejection rod, which are m1, m2 and m3 respectively;

[0017] S4: Rotate the rotating sleeve to compress the spring and generate spring force; rotate the butterfly nut to pull up the ejection rod through the pull rope until it contacts the fixed sleeve; supply power to the upper coil so that the armature contacts the lower end surface of the ejection rod; cut the pull rope and check whether the upper end surface of the armature is separated from the lower end surface of the ejection rod;

[0018] S5: If the upper end surface of the armature is still in contact with the lower end surface of the ejection rod, repeat step S4 and gradually further twist the rotating sleeve to increase the spring force until the upper end surface of the armature is separated from the lower end surface of the ejection rod;

[0019] Repeat step S4 and rotate the rotating sleeve in the opposite direction to reduce the spring force until the upper end surface of the armature and the lower end surface of the ejection rod are just separated;

[0020] Measure the distance between the fixed collar surface F and the rotating collar surface N, recorded as x1; according to the relationship between x1 and the compression force F on the spring and the spring length x, calculate the work W done by the spring force in this process s1 ;

[0021] S6: Repeat step S4, and continue to compress the spring further by twisting the rotating sleeve to generate a greater spring force; observe whether the upper end surface of the armature contacts the lower end surface of the ejection rod after being rebounded by the static block after the pull rope is cut off;

[0022] S7: If the upper end surface of the armature is still separated from the lower end surface of the ejection rod, repeat step S4 to continue increasing the spring force until the upper end surface of the armature contacts the lower end surface of the ejection rod;

[0023] Repeat step S5, and turn the rotating sleeve in the reverse direction until the armature is found to rebound to the upper stopper side.

[0024] Measure the distance between the fixed collar surface F and the rotating collar surface N, recorded as x2; according to the relationship between x2 and the compression force F on the spring and the spring length x, calculate the work W done by the spring force in this process s2 ;

[0025] S8: The work done by the spring force during the separation of the upper end surface of the armature and the lower end surface of the ejection rod W s1 , the work done by the spring force when the armature just rebounds to the upper stopper side W s2 , W c , as well as the masses of the armature, the moving block and the ejection rod, calculate the velocity v of the moving block and the static block just before the collision, and the collision recovery coefficient e between the moving block and the static block.

[0026] In S5, the work W done by the spring force is calculated based on the relationship between x1 and the compression force F on the spring and the spring length x. s1 , including: calculating the spring force f1 when the ejection rod contacts the fixed sleeve and the spring force f2 when the ejection rod contacts the lower end cover according to the relationship between x1 and the compression force F of the spring and the spring length x;

[0027]

[0028] The velocity v of the moving block just before the collision with the static block is:

[0029] The collision recovery coefficient e between the moving block and the static block is:

[0030]

[0031] In summary, this application at least includes the following beneficial technical effects:

[0032] 1. The collision restitution coefficient measuring device disclosed in the present invention is mainly a mechanical structure, does not involve sensors or electronic equipment, has a simple structure, low development cost, and is easy to implement.

[0033] 2. The collision recovery coefficient measuring device disclosed in the present invention is particularly suitable for measuring the collision recovery coefficient when small-sized parts collide at low speed.

[0034] 3. In the collision recovery coefficient measuring device disclosed in the present invention, the moving block and the static block are independent structures, and the collision contact surface between the two can be designed according to the actual collision contact surface, so that the collision recovery coefficient test result is closer to the actual situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of a collision restitution coefficient measuring device of the present invention;

[0036] Figure 2It is a schematic diagram of the structure of the catapult;

[0037] Figure 3 It is a cross-sectional schematic diagram of the matching structure of the draw hook and the upper end cover;

[0038] Figure 4 It is a cross-sectional schematic diagram of the cooperation structure between the ejection rod and the rotating sleeve;

[0039] Figure 5 It is a schematic diagram of the structure of the electromagnet. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0041] The present application embodiment discloses a collision recovery coefficient measuring device, such as Figure 1 As shown, it specifically includes: an ejector 1, an electromagnet 2, a moving block 3, a static block 4, and a base 5; the ejector 1 is connected to the electromagnet 2 by screws, the electromagnet 2 is connected to the moving block 3 by threads, and the static block 4 is connected to the base 5 by screws.

[0042] Figure 2 The structure diagram of the ejector 1 is one of the power sources that affect the movement of the moving block 3, and specifically includes: a fixed sleeve 1-1, a rotating sleeve 1-2, a lower end cover 1-3, an upper end cover 1-4, a spring 1-5, an ejection rod 1-6, a hook 1-7, a butterfly nut 1-8 and a pull rope 1-9; the fixed sleeve 1-1 and the rotating sleeve 1-2 are connected by fine pitch threads, and their coaxiality is limited by the mating surface, and the fixed sleeve 1-1 and the lower end cover 1-3 are connected by screws Connection, the rotating sleeve 1-2 and the upper end cover 1-4 are connected by screws; the ejection rod 1-6 is installed between the rotating sleeve 1-2 and the lower end cover 1-3, and cooperates with the rotating sleeve 1-2 and the lower end cover 1-3 through thin shafts at both ends; the spring 1-5 is installed between the ejection rod 1-6 and the rotating sleeve 1-2; the draw hook 1-7 passes through the upper end cover 1-4 and is connected to the butterfly nut 1-8 through threads; the ejection rod 1-6 and the draw hook 1-7 are connected by a pull rope 1-9.

[0043] Figure 3 It is a cross-sectional view of the matching part of the upper end cover 1-4 and the draw hook 1-7. A rectangular limit groove is opened on the upper end cover 1-4, and the hook end of the draw hook 1-7 is a flat structure. The flat structure of the draw hook 1-7 matches with the rectangular limit groove of the upper end cover 1-4, so that when the rotating butterfly nut 1-8 rotates, the draw hook 1-7 can only move up and down, and cannot rotate relative to the upper end cover 1-4;

[0044] Figure 4It is a cross-sectional view of the matching part of the rotating sleeve 1-2 and the ejection rod 1-6. A rectangular limiting groove is provided on the rotating sleeve 1-2, and the hook end of the ejection rod 1-6 is a flat structure. The flat structure of the ejection rod 1-6 matches with the rectangular limiting groove of the rotating sleeve 1-2, so that when the rotating sleeve 1-2 rotates, the ejection rod 1-6 can only move up and down relative to the rotating sleeve 1-2, but cannot rotate relative to the rotating sleeve 1-2. The annular surface E of the fixed sleeve 1-1 and the annular surface F are on the same plane, and the annular surface M of the rotating sleeve 1-2 and the annular surface N are on the same plane. The distance between the annular surface N and the annular surface F is equal to the length of the spring when the ejection rod 1-6 is pulled up and contacts the fixed sleeve 1-1.

[0045] Figure 5 It is a structural diagram of the electromagnet 2, which is one of the power sources affecting the movement of the movable block 3, and specifically includes: an upper stop 2-1, a lower stop 2-2, a jacket 2-3, a magnetic steel 2-4, an upper coil 2-5, a lower coil 2-6, an armature 2-7, and a skeleton 2-8; the jacket 2-3 is connected to the upper stop 2-1 and the lower stop 2-2 by screws respectively; the magnetic steel 2-4 is bonded to the middle part of the skeleton 2-8, the upper coil 2-5 and the lower coil 2-6 are respectively wound on the skeleton 2-8 and are located on both sides of the magnetic steel 2-4, the whole set is between the upper stop 2-1 and the lower stop 2-2, and the cavity between the jacket 2-3, the upper stop 2-1, the lower stop 2-2, the upper coil 2-5 and the lower coil 2-6 is filled with thermal conductive glue; the armature 2-7 is located in the skeleton 2-8 and passes through the upper stop 2-1 and the lower stop 2-2. The magnet 2-4 is an annular permanent magnetic material, and its two poles are respectively located on the cylindrical surface in contact with the frame 2-8 and the cylindrical surface in contact with the outer sleeve 2-3; the upper stopper 2-1, the lower stopper 2-2, the outer sleeve 2-3, and the armature 2-7 are soft magnetic materials; both ends of the armature 2-7 have thin shafts, and the end of the thin shaft at one end is a threaded structure for connecting with the static block 4. When the armature 2-7 is close to the upper stopper 2-1, the armature 2-7 is subjected to the upward magnetic steel force generated by the magnet 2-4; when the armature 2-7 is close to the lower stopper 2-2, the armature 2-7 is subjected to the downward magnetic steel force; when the armature 2-7 is located at a certain position in the middle, the force on the armature 2-7 is zero.

[0046] like Figure 1 As shown, when the electromagnet 2 is installed on the ejector 1 and the ejection rod 1-6 is pulled up to contact with the fixed sleeve 1-1, there is a gap Δ between the ejection rod 1-6 and the lower end cover 1-3. This position is the displacement zero point. If the armature 2-7 is gradually moved toward the lower stop iron 2-2 until the magnetic steel force is zero, the displacement at this time is recorded as δ0. In order to ensure that a collision recovery coefficient measuring device of the present invention can be tested normally, it is required that Δ<δ0.

[0047] When the armature 2-7 is on the side of the upper stop 2-1, the armature 2-7 can be moved to the side of the lower stop 2-2 by energizing the lower coil 2-6; when the armature 2-7 is on the side of the lower stop 2-2, the armature 2-7 can be moved to the side of the upper stop 2-1 by energizing the upper coil 2-5, and the position of the armature 2-7 can be reset to the top.

[0048] The steps of measuring the collision restitution coefficient of the present invention are as follows:

[0049] S1. Calculation of magnetic force work done by armature 2-7 from the position where magnetic force is zero to the process where movable block 3 and stationary block 4 just touch each other: take the position where magnetic force is zero on armature 2-7 as the displacement zero point, move armature 2-7 in the direction of lower stop 2-2 by a small displacement, the position at this time is recorded as δ1, and measure magnetic force, recorded as F1; continue to move armature 2-7 in the direction of lower stop 2-2 by a small displacement, the position at this time is recorded as δ2, and measure magnetic force, recorded as F2; ​​..., until armature 2-7 is installed with movable block 3, movable block 3 and stationary block 4 touch each other, the displacement of armature at this time is recorded as δn, and magnetic force on armature 2-7 is recorded as Fn, then magnetic force work done is calculated according to the following formula:

[0050]

[0051] S2. Spring original length and stiffness test: measure the length of the spring in the natural state without force, recorded as x0; measure the length of the spring under a certain compression force f a The length x under action a , then the spring stiffness k is calculated according to the following formula:

[0052]

[0053] The relationship between the compression force F on the spring and the spring length x is as follows:

[0054] f=k(x0-x)(1-3)

[0055] S3. Measure the masses of the armature 2-7, the movable block 3, and the ejection rod 1-6. The masses of the three parts are recorded as m1, m2, and m3 respectively.

[0056] S4. Assemble the catapult 1, the electromagnet 2, the moving block 3, the static block 4, and the base 5.

[0057] S5. Compress the spring 1-5 by twisting the rotating sleeve 1-2 to generate spring force. Rotate the butterfly nut 1-8 to pull up the ejection rod 1-6 through the pull rope 1-9 until it contacts the fixed sleeve 1-1, and supply power to the upper coil 2-5 so that the armature 2-7 is on the side of the upper stopper 2-1, and the upper end surface of the armature 2-7 contacts the lower end surface of the ejection rod 1-6. Cut the pull rope and check whether the upper end surface of the armature 2-7 is separated from the lower end surface of the ejection rod 1-6 through the observation window on the lower end cover 1-3.

[0058] S6. If the upper end surface of the armature 2-7 is still in contact with the lower end surface of the ejection rod 1-6, it means that the armature 2-7 is still on the side of the upper stop iron 2-1. Then follow step S5 and further turn the rotating sleeve 1-2 to continue to increase the spring force until the upper end surface of the armature 2-7 is separated from the lower end surface of the ejection rod 1-6, which means that the armature 2-7 has moved to the side of the lower stop iron 2-2. At this time, repeat step S5 and turn the rotating sleeve 1-2 in the opposite direction to fine-tune the spring force to reduce the spring force. In order to find out the state when the upper end surface of the armature 2-7 and the lower end surface of the ejection rod 1-6 are just separated, measure the distance between the annular surface F of the fixed sleeve 1-1 and the annular surface N of the rotating sleeve 1-2, recorded as x1, and calculate the spring force when the ejection rod 1-6 is in contact with the fixed sleeve 1-1 and the spring force when the ejection rod 1-6 is in contact with the lower end cover 1-3 according to formula (1-3), recorded as f1 and f2 respectively. The work done by the spring force in this process is W s1 Calculated as follows:

[0059]

[0060] S7, repeat step S5, continue to further compress the spring 1-5 by twisting the rotating sleeve 1-2, and generate a greater spring force. Rotate the butterfly nut 1-8 to pull up the ejection rod 1-6 through the pull rope 1-9 until it contacts the fixed sleeve 1-1, and power the upper coil 2-5, so that the armature 2-7 is on the side of the upper stop 2-1, and the upper end face of the armature 2-7 contacts the lower end face of the ejection rod 1-6, cut the pull rope, and check through the observation window on the lower end cover 1-3 whether the upper end face of the armature 2-7 contacts the lower end face of the ejection rod 1-6 (rebounded by the static block 4 and then contacted with the lower end face of the ejection rod 1-6).

[0061] S8, if the upper end surface of the armature 2-7 is still separated from the lower end surface of the ejection rod 1-6, it means that the armature 2-7 moves to the side of the lower stopper 2-2, the movable block 3 collides with the static block 4, and finally contacts with the static block. In this case, repeat step S5, continue to increase the spring force, refer to S8, until the upper end surface of the armature 2-7 contacts with the lower end surface of the ejection rod 1-6, which means that the armature 2-7 first moves to the side of the lower stopper 2-2, the movable block 3 collides with the static block 4, and then the movable block 3 drives the armature 2-7 to rebound to the side of the upper stopper 2-1. Repeat step S5, reverse the rotation sleeve 1-2, fine-tune the spring force, refer to S7, find the state where the armature 2-7 just rebounds to the side of the upper stopper 2-1, measure the distance between the annular surface F of the fixed sleeve 1-1 and the annular surface N of the rotating sleeve 1-2, record it as x2, and calculate the spring force when the ejection rod 1-6 contacts the fixed sleeve 1-1 and the spring force when the ejection rod 1-6 contacts the lower end cover 1-3 according to formula (1-3), record them as f3 and f4 respectively. The work done by the spring force in this process is W s2 Calculated as follows:

[0062]

[0063] S9, the velocity v of the moving block 3 and the static block 4 just before the collision, and the collision recovery coefficient e are calculated according to the following formulas:

[0064]

[0065] Factors affecting the collision speed include the magnitude of the magnetic potential energy of the electromagnet 2 and the total mass of the armature 2-7 and the movable block 3; when the electromagnet 2 has been determined, the collision speed can be adjusted by adjusting the mass of the movable block 3; when the required collision speed cannot be adjusted by adjusting the mass of the movable block armature 2-7, the collision speed can be adjusted by first replacing the electromagnet 2 with a different magnetic potential energy and then adjusting the mass of the movable block.

[0066] The beneficial effects of the present invention are as follows: the collision restitution coefficient measuring device disclosed in the present invention has a main mechanical structure, does not involve sensors or electronic equipment, has a simple structure, low development cost, and is easy to implement; it is particularly suitable for measuring the collision restitution coefficient during low-speed collision between smaller parts; the moving block and the static block are independent structures, and the collision contact surface between the two can be designed according to the actual collision contact surface, so that the collision restitution coefficient test result is closer to the actual situation.

[0067] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0068] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A collision restitution coefficient measuring device, characterized in that: It comprises an ejector (1), an electromagnet (2), a moving block (3), a static block (4) and a base (5), wherein the static block (4) and the base (5) are connected by screws; The electromagnet (2) comprises a fixed structure and a moving part armature (2-7); one end of the fixed structure is connected to a base (5) and the other end is connected to an ejector (1); the armature (2-7) slides relative to the fixed structure in a direction approaching or moving away from a stationary block (4); one end of the armature (2-7) close to the stationary block (4) is connected to a moving block (3) and the other end faces an output end of the ejector (1); the fixed structure is used to generate a magnetic steel force on the armature (2-7) in a direction of the ejector (1) or in a direction of the stationary block (4) according to the position of the armature (2-7); The output end of the ejector (1) is used to apply an ejection force to the armature (2-7).

2. A collision restitution coefficient measuring device according to claim 1, characterized in that: The ejector (1) comprises a fixed sleeve (1-1), a rotating sleeve (1-2), a lower end cover (1-3), an upper end cover (1-4), a spring (1-5), an ejection rod (1-6), a draw hook (1-7), a butterfly nut (1-8) and a draw rope (1-9); The lower end cover (1-3) is connected to one end of the fixed sleeve (1-1), the other end of the fixed sleeve (1-1) is connected to the rotating sleeve (1-2) through a fine thread, the rotating sleeve (1-2) is connected to the upper end cover (1-4), and the electromagnet (2) is connected to the lower end cover (1-3); the ejection rod (1-6) passes through the fixed sleeve (1-1) and the rotating sleeve (1-2), and is slidably connected to the fixed sleeve (1-1) and the rotating sleeve (1-2) along the axial direction of the rotating sleeve (1-2), and one end of the armature (2-7) is opposite to the end of the ejection rod (1-6); the spring (1-5) is installed on the ejection rod (1-6) and a rotating sleeve (1-2) so that the ejection rod (1-6) applies an ejection force to the armature (2-7); the butterfly nut (1-8) is rotatably connected to the upper end cover (1-4), and the draw hook (1-7) is threadedly connected to the butterfly nut (1-8); the moving direction of the ejection rod (1-6) is along the axial direction of the fixed sleeve (1-1), and the draw rope (1-9) is connected between the draw hook (1-7) and the ejection rod (1-6); by rotating the butterfly nut (1-8), the draw hook (1-7) is driven to move, and the draw hook (1-7) drives the ejection rod (1-6) to move to contact with the fixed sleeve (1-1).

3. A collision restitution coefficient measuring device according to claim 2, characterized in that: The upper end cover (1-4) is provided with a rectangular limiting groove, the hook end of the pull hook (1-7) is a flat structure, and the flat structure of the pull hook (1-7) cooperates with the rectangular limiting groove of the upper end cover (1-4).

4. A collision restitution coefficient measuring device according to claim 2, characterized in that: The rotating sleeve (1-2) is provided with a rectangular limiting groove, and the ejection rod (1-6) has a flat structural part, which cooperates with the rectangular limiting groove.

5. The device for measuring the coefficient of restitution according to claim 2, characterized in that: The fixed sleeve (1-1) has an inner wall surface provided with an annular surface E and an outer wall surface provided with an annular surface F, the annular surface E and the annular surface F are on the same plane, the rotating sleeve (1-2) has an inner surface provided with an annular surface M and an outer wall surface provided with an annular surface N, the annular surface M and the annular surface N are on the same plane; The ejection rod (1-6) is provided with a convex ring, the annular surface E is located on the side of the convex ring away from the movable block (3) and is used to limit the moving stroke of the convex ring, the spring (1-5) is in contact with the side of the convex ring away from the movable block (3), and the spring (1-5) is in contact with the annular surface M.

6. The device for measuring the coefficient of restitution according to claim 1, characterized in that: The fixed structure comprises an upper stopper (2-1), a lower stopper (2-2), a jacket (2-3), a magnetic steel (2-4), an upper coil (2-5), a lower coil (2-6) and a frame (2-8); An upper stopper (2-1) and a lower stopper (2-2) are respectively connected to two ends of the outer sleeve (2-3); the upper stopper (2-1) is used to connect the ejector (1), and the lower stopper (2-2) is used to connect the base (5); The outer sleeve (2-3) is in the shape of a cylinder with two ends open, the frame (2-8) is located inside the outer sleeve (2-3), and the magnetic steel (2-4) is bonded to the middle part of the outside of the frame (2-8); the upper coil (2-5) and the lower coil (2-6) are respectively wound on the frame (2-8) and located on both sides of the magnetic steel (2-4); the armature (2-7) is located inside the frame (2-8), and the two ends of the armature (2-7) pass through the upper stopper (2-1) and the lower stopper (2-2) respectively; The magnetic steel (2-4) is an annular permanent magnetic material, and its two poles are respectively located on the cylindrical surface in contact with the frame (2-8) and the cylindrical surface in contact with the outer sleeve (2-3); the upper stopper (2-1), the lower stopper (2-2), the outer sleeve (2-3) and the armature (2-7) are soft magnetic materials.

7. The device for measuring the coefficient of restitution according to claim 1, characterized in that: When the ejection rod (1-6) is pulled up to contact the fixed sleeve (1-1), a gap Δ exists between the ejection rod (1-6) and the lower end cover (1-3). This position is regarded as the zero point of displacement. If the armature (2-7) is gradually moved in the direction of the lower stop iron (2-2) until the magnetic steel force is zero, the displacement at this time is recorded as δ0, Δ<δ0.

8. A method for measuring a collision restitution coefficient, characterized in that: The method of measuring a collision restitution coefficient according to any one of claims 1 to 6 comprises: S1: Calculate the work W done by the magnetic force when the armature (2-7) moves from the position where the magnetic force is zero to the point where the moving block (3) and the stationary block (4) just touch each other. c ; S2: Obtain the relationship between the compression force F on the spring and the spring length x; S3: Measure the masses of the armature (2-7), the moving block (3) and the ejection rod (1-6) as m1, m2 and m3 respectively; S4: rotating the rotating sleeve (1-2) to compress the spring (1-5) and generate spring force; rotating the butterfly nut (1-8) to pull up the ejection rod (1-6) through the pull rope (1-9) until it contacts the fixed sleeve (1-1); supplying power to the upper coil (2-5) so that the armature (2-7) contacts the lower end surface of the ejection rod (1-6); cutting the pull rope and checking whether the upper end surface of the armature (2-7) is separated from the lower end surface of the ejection rod (1-6); S5: If the upper end surface of the armature (2-7) is still in contact with the lower end surface of the ejection rod (1-6), repeat step S4 and gradually further twist the rotating sleeve (1-2) to increase the spring force until the upper end surface of the armature (2-7) is separated from the lower end surface of the ejection rod (1-6); Repeat step S4 and reversely rotate the rotating sleeve (1-2) to reduce the spring force until the upper end surface of the armature (2-7) and the lower end surface of the ejection rod (1-6) are just separated; Measure the distance between the annular surface F of the fixed sleeve (1-1) and the annular surface N of the rotating sleeve (1-2), recorded as x1; calculate the work W done by the spring force in this process based on the relationship between x1 and the compression force F on the spring and the spring length x. s1 ; S6: Repeat step S4, continue to twist the rotating sleeve (1-2) to further compress the spring (1-5) to generate a greater spring force; observe whether the upper end surface of the armature (2-7) contacts the lower end surface of the ejection rod (1-6) after being rebounded by the static block (4) after the pull rope is cut off; S7: If the upper end surface of the armature (2-7) and the lower end surface of the ejection rod (1-6) are still separated, repeat step S4 and continue to increase the spring force until the upper end surface of the armature (2-7) contacts the lower end surface of the ejection rod (1-6); Repeat step S5, and rotate the rotating sleeve (1-2) in the reverse direction until the armature (2-7) just rebounds to the side of the upper stopper (2-1). Measure the distance between the annular surface F of the fixed sleeve (1-1) and the annular surface N of the rotating sleeve (1-2), recorded as x2; calculate the work W done by the spring force in this process based on the relationship between x2 and the compression force F on the spring and the spring length x s2 ; S8: The work W done by the spring force during the separation process between the upper end surface of the armature (2-7) and the lower end surface of the ejection rod (1-6) s1 , the armature (2-7) just rebounds to the side of the upper stopper (2-1), and the work done by the spring force is W s2 , W c , and the masses of the armature (2-7), the movable block (3) and the ejection rod (1-6), and the velocity v of the movable block (3) and the stationary block (4) just before the collision, and the collision recovery coefficient e between the movable block (3) and the stationary block (4) are calculated.

9. A method for measuring a collision restitution coefficient according to claim 8, characterized in that: In S5, the work W done by the spring force is calculated based on the relationship between x1 and the compression force F on the spring and the spring length x. s1 , including: calculating the spring force f1 when the ejection rod (1-6) contacts the fixed sleeve (1-1) and the spring force f2 when the ejection rod (1-6) contacts the lower end cover (1-3) according to the relationship between x1 and the compression force F of the spring and the spring length x; 10. A method for measuring a collision restitution coefficient according to claim 7, characterized in that: The velocity v of the moving block (3) and the stationary block (4) just before the collision is: The collision recovery coefficient e between the moving block (3) and the stationary block (4) is:

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