A constant force loading device based on coil spring

Abstract

The present invention relates to the field of aerospace mechanism products, and specifically, to a constant force loading device based on a coil spring, comprising: a loading platform, wherein the loading platform comprises a fixed portion and a moving portion, wherein the moving portion and the fixed portion are cooperatively connected; a coil spring assembly, wherein the coil spring assembly is fixedly arranged on one side of the fixed portion, and the coil spring assembly is connected to the moving portion via a pulley assembly arranged at the top of a fixed plate; and the coil spring assembly can drive the moving portion to perform one-dimensional motion on the fixed portion. Compared with the prior art, the technical solution proposed in this application has the following beneficial effects: the present invention is different from the existing loading test method, and the one-dimensional linear motion during the mechanism capture test is converted into the relative rotation of the coil spring by adjusting the layout of the pulley assembly, and the coil spring is used as the external load input. By reasonably matching the mechanical properties of the coil spring and the external dimensions of the tower pulley, a wide range of constant load output is achieved.

Description

Technical Field

[0001] The present invention relates to the field of aerospace mechanism products, and in particular to a constant force loading device based on a coil spring. Background Art

[0002] Most spacecraft, such as space probes, space shuttles, spacecraft, and space stations, feature small capture and locking mechanisms to achieve capture and rigid connection between components or cabins. To ensure reliable on-orbit operation, the capture and locking mechanism needs to be able to overcome a certain amount of external resistance during the capture process. However, current ground-based loading tests of the capture capabilities of such mechanisms primarily use weights, cylindrical coil springs, and tensile testing machines to provide the load. Using weights for loading can achieve a constant load during the capture process, but due to the cumbersome testing process, it is only suitable for room-temperature performance testing. Using cylindrical coil springs for loading is simple in structure, but it cannot achieve a constant load throughout the capture process. Using tensile testing machines for loading can achieve a constant load during the test process, but the loading control process is complex, and there is a certain delay in the load output, which has certain limitations in actual testing. Currently, ground-based loading tests of the capture capabilities of small capture and locking mechanisms still lack a loading device with a simple structure, fast response speed, wide applicability, and the ability to achieve a constant load output. Summary of the Invention

[0003] The purpose of the present invention is to solve the deficiencies of the prior art and provide a loading test device with a simple structure and convenient operation.

[0004] To achieve the above-mentioned purpose, the present invention provides a constant force loading device based on a coil spring, comprising: a loading platform, wherein the loading platform includes a fixed part and a moving part, and the moving part and the fixed part are cooperatively connected; a coil spring assembly, wherein the coil spring assembly is fixedly arranged on one side of the fixed part, and the coil spring assembly is connected to the moving part through a pulley assembly arranged at the top of the fixed plate; the coil spring assembly can drive the moving part to perform one-dimensional motion on the fixed part.

[0005] Preferably: the fixed part includes a bottom plate, a top plate and a guide rod, the moving part includes a loading plate, a linear bearing and a connecting block, the several guide rods are vertically arranged between the surface of the bottom plate and the back of the top plate, the loading plate is sleeved on the middle of the guide rod, the linear bearing is arranged at the bottom of the loading plate, the connecting block is arranged in the middle of the surface of the loading plate, and the fixed part and the moving part are cooperated and connected as a whole.

[0006] Preferably: the bottom plate has a mechanical interface for installing the coil spring assembly, a through hole is opened in the center of the top plate for passing the wire rope, the top plate has a mechanical interface for installing the pulley assembly, one side of the connecting block is fixedly connected to the loading plate by a connecting screw, and the other side is connected to the wire rope of the pulley assembly.

[0007] Preferably: the coil spring assembly includes a tower pulley, which is composed of a conical part and a cylindrical part: the conical surface has a spiral groove for constraining the wire rope, and the end of the groove has a mounting hole for fixing the end of the wire rope; the inner side of the conical part and the cylindrical part each has a cylindrical cavity for installing the coil spring, and the middle is a cavity for passing the transmission shaft.

[0008] Preferably, the coil spring assembly further comprises two coil springs, both ends of which are fixed to the cavities on both sides of the tower pulley and the transmission shaft via coil spring mounting screws, and the rotation direction of the coil spring is opposite to the rotation direction of the conical groove of the tower pulley.

[0009] Preferably, the coil spring assembly further comprises bearing end covers, which are fixed on both sides of the tower pulley and connect the tower pulley and the transmission shaft via rolling bearings, wherein the transmission shaft has the coil spring mounting interface.

[0010] Preferably, the coil spring assembly further includes a first support frame and a second support frame, wherein the first support frame and the second support frame are used to fix the transmission shaft and are fixedly connected to the loading platform.

[0011] Preferably: the coil spring assembly also includes a turbine and a worm, the worm is mounted on the second bracket through a bearing and is fixed using the worm bearing end cover, one end of the worm is square for rotation with a wrench, the turbine is fixed to the drive shaft through a rectangular spline and forms a meshing relationship with the worm.

[0012] Preferably: the pulley assembly includes a pulley bracket, a pulley and a pulley shaft, there are two pulley brackets, which are installed on the top plate of the loading platform, and the pulley is installed on the pulley bracket through the pulley shaft and fasteners, one end of the steel wire rope is thickened and protruded, and the other end has a threaded connecting rod, the thickened end of the steel wire rope is fixed to the tower pulley, and is wound along the conical groove of the tower pulley, and then guided by two pulleys, passes through the center hole of the top plate of the loading platform and is fixed to the connecting block.

[0013] Compared with the prior art, the technical solution proposed in this application has the following beneficial effects: the present invention is different from the existing loading test method. By adjusting the layout of the pulley assembly, the one-dimensional linear motion during the mechanism capture test is converted into the relative rotation of the coil spring, and the coil spring is used as the external load input. By reasonably matching the mechanical properties of the coil spring and the external dimensions of the tower pulley, a larger range of constant load output is achieved; the mounting plate adopts a T-slot design to meet the installation requirements of mechanism products of different sizes; the present invention realizes loading tests of different capture ranges by changing the size of the connecting block; the present invention adjusts the coil spring load through a worm gear to achieve a larger range of load adjustment; the present invention has a simple structure and is easy to operate, and can realize the capture capacity loading test of small mechanisms in multiple environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0015] Figure 1 This is an overall structural diagram of a constant force loading device based on a coil spring in the present invention;

[0016] Figure 2 A top view of a constant force loading device based on a coil spring in the present invention;

[0017] Figure 3 This is a front view of a constant force loading device based on a coil spring in the present invention;

[0018] Figure 4 It is a right sectional view of a coil spring assembly of a coil spring-based constant force loading device in the present invention;

[0019] Figure 5 It is a partial cross-sectional view of a coil spring assembly of a constant force loading device based on a coil spring in the present invention.

[0020] In the figure: 11-base plate, 12-loading plate, 13-top plate, 14-guide rod, 15-linear bearing, 16-connecting block, 17-connecting screw; 21-tower pulley, 22-coil spring, 23-drive shaft, 24-bearing end cover, 25-first support frame, 26-second support frame, 27-worm, 28-worm wheel, 29-worm bearing end cover, 211-coil spring fixing screw; 31-pulley bracket, 32-pulley, 33-pulley shaft, 34-wire rope. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe and discuss the technical solutions in the embodiments of the present invention in conjunction with the drawings of the present invention. Obviously, what is described here is only a part of the examples of the present invention, not all the examples. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a central component. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] See also Figures 1 to 5 This embodiment discloses a constant force loading device based on a coil spring, including a loading platform 1, a coil spring assembly 2 and a pulley assembly 3.

[0025] The loading platform includes a base plate 11, a loading plate 12, a top plate 13, a guide rod 14, a linear bearing 15, a connecting block 16, a connecting screw 17 and related fasteners. The base plate 11 and the top plate 12 are bolted together as a whole through the guide rod 13, and the loading plate 12 can move in one dimension through the guide plate 13. The linear bearing 15 is installed on the loading plate 12, providing a guiding function for the loading plate 12 and moving linearly along the guide rod 13 with the loading plate 12. The base plate 11 and the loading plate 12 have T-slots, which can be used to install test mechanism products of different specifications. The base plate 11 has a mechanical interface for installing the coil spring assembly 2. The top plate 13 has a through hole in the center for passing the wire rope 34, and has a mechanical interface for installing the pulley support 21. One side of the connecting block 16 is fixedly connected to the loading plate 16 by a connecting screw 17, and the other side is connected to the pulley wire rope 34.

[0026] The coil spring assembly includes a tower pulley 21, a coil spring 22, a drive shaft 23, a bearing end cap 24, a first support frame 25, a second support frame 26, a worm 27, a worm wheel 28, a worm bearing end cap 29, coil spring fixing screws 211, and related fasteners. The tower pulley 21 consists of a conical body and a cylindrical portion. The conical surface has a spiral groove for restraining a steel wire rope 34, and one side of the groove has a mounting hole for securing the end of the steel wire rope 34. Both the conical body and the cylindrical portion have a cylindrical cavity on either side for mounting the coil spring 22, with a hollow center for passing the drive shaft 23. Two coil springs 22 are secured to the cylindrical cavity of the tower pulley 21 and to the drive shaft 23 via coil spring mounting screws 211. Once installed, the coil springs 23 rotate in the opposite direction of the conical groove on the tower pulley 21. The bearing end caps 24 are fixed to both sides of the tower pulley 21 and connect the tower pulley 21 to the drive shaft 23 via rolling bearings. The first and second support frames 25 and 26 support the drive shaft 23 and are fixed to the base plate 11 of the loading platform 1. The second support frame 26 has two side panels with bearing chambers for the bearings. A worm 27 is mounted on the second support frame 26 via bearings and secured with a worm bearing end cap 29. One end of the worm 27 is squared to accommodate a wrench. The turbine 28 is secured to the drive shaft 23 via a rectangular spline with an interference fit and meshes with the worm 27.

[0027] The pulley assembly consists of two pulley brackets 31, pulleys 32, pulley shafts 33, wire ropes 34, and associated fasteners. Two pulley brackets 31 are mounted on the loading platform's top plate 13. Pulleys 32 are attached to the pulley brackets 31 via pulley shafts 33 and fasteners. The wire ropes 34 have a thickened protrusion at one end and a threaded connecting rod at the other. The thickened end of the wire ropes 34 is secured to the tower pulley 21 and winds along the conical grooves of the tower pulley 21. The ropes are then guided through the two pulleys 32, passed through the center hole of the loading platform's top plate 13, and secured to the connecting block 16.

[0028] The working principle of this embodiment is described below:

[0029] When the present invention is used, the worm 26 is rotated to drive the worm wheel 27 to rotate, and then the transmission shaft 23 is driven to rotate. Since one end of the two coil springs 22 is fixed on the transmission shaft 23, the loading plate 12 is pulled upward by the wire rope 34 until the loading block 16 contacts the top plate 14. During this process, due to the deadweight of the loading plate 12, the tower pulley 21 and the transmission shaft 23 rotate relative to each other, causing the coil spring 22 to store energy. Since the worm gear has a reverse self-locking function, the state of the coil spring 22 after energy storage can be maintained and it continues to rotate with the worm 26. After that, the tower pulley 21 no longer rotates, and the transmission shaft 23 rotates to cause the coil spring 22 to continue to store energy. The tension of the wire rope 34 increases, and the tension of the wire rope 34 is finally adjusted to the test load + the weight of the loading plate.

[0030] Since both the loading platform base plate 11 and the loading plate 12 are designed with T-slots, the active end and the driven end of the small capture and locking mechanism to be tested can be installed on the loading platform base plate 11 and the loading plate 12 respectively through the adapter fixture. When the small capture and locking mechanism product is tested for its capture ability, the loading plate 12 moves downward along with the driven end of the mechanism product, driving the wire rope 34 to move downward. Guided by the two pulleys 32, the tower pulley 21 rotates, and the wire rope 34 is released along the groove on the tower pulley 21. Due to the reverse self-locking of the worm gear, the transmission shaft 23 of the coil spring assembly 2 is fixed, and the coil spring 22 stores energy. The coil spring torque T is related to the rotation angle θ, and T = wire rope tension F × radius r of the wire rope tension point. During manufacturing, it is ensured that the rate of change of T and r with θ is the same, so the tension F of the wire rope 34 is a constant value, that is, constant force loading is achieved.

[0031] The present invention can realize loading tests with different capture ranges by replacing loading blocks 16 of different specifications.

[0032] The present invention can realize loading tests under different loads by adjusting the worm 27 .

[0033] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and that one or more of the above embodiments may be combined. Those skilled in the art may make various changes, modifications, or combinations within the scope of the claims, which do not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments may be combined with each other in any manner.

Claims

1. A constant force loading device based on a coil spring, characterized in that include A loading platform, comprising a fixed portion and a moving portion, wherein the moving portion and the fixed portion are cooperatively connected; a coil spring assembly, the coil spring assembly being fixedly disposed on one side of the fixed portion and connected to the moving portion via a pulley assembly disposed on the top of the fixed plate; The coil spring assembly can drive the moving part to perform one-dimensional movement on the fixed part; The fixed part includes a bottom plate, a top plate and a guide rod, and the moving part includes a loading plate, a linear bearing and a connecting block. The guide rods are vertically arranged between the surface of the bottom plate and the back of the top plate. The loading plate is sleeved on the middle of the guide rods. The linear bearing is arranged at the bottom of the loading plate. The connecting block is arranged in the middle of the surface of the loading plate. The fixed part and the moving part are connected together as a whole. The bottom plate has a mechanical interface for installing the coil spring assembly, a through hole is opened in the center of the top plate for passing the wire rope, and the top plate has a mechanical interface for installing the pulley assembly. One side of the connecting block is fixedly connected to the loading plate by a connecting screw, and the other side is connected to the wire rope of the pulley assembly; The coil spring assembly includes a tower pulley, which is composed of a conical part and a cylindrical part: the conical surface is provided with a spiral groove for constraining the wire rope, and the end of the groove is provided with a mounting hole for fixing the end of the wire rope; the inner side of the conical part and the cylindrical part each has a cylindrical cavity for installing the coil spring, and the middle is a cavity for passing the transmission shaft.

2. A constant force loading device based on a coil spring according to claim 1, characterized in that The coil spring assembly also includes two coil springs, both ends of which are fixed to the cavities on both sides of the tower pulley and the transmission shaft through coil spring mounting screws, and the rotation direction of the coil spring is opposite to the rotation direction of the conical groove of the tower pulley.

3. A constant force loading device based on a coil spring according to claim 2, characterized in that The coil spring assembly also includes bearing end covers, which are fixed on both sides of the tower pulley and connected to the tower pulley and the transmission shaft through rolling bearings. The transmission shaft has the coil spring mounting interface.

4. A constant force loading device based on a coil spring according to claim 3, characterized in that The coil spring assembly further includes a first support frame and a second support frame, wherein the first support frame and the second support frame are used to fix the transmission shaft and are fixedly connected to the loading platform.

5. A constant force loading device based on a coil spring according to claim 4, characterized in that The coil spring assembly also includes a worm wheel and a worm. The worm is mounted on the second support frame through a bearing and is fixed using the worm bearing end cover. One end of the worm is square for rotation with a wrench. The worm wheel is fixed to the drive shaft through a rectangular spline and forms a meshing relationship with the worm.

6. A constant force loading device based on a coil spring according to claim 5, characterized in that The pulley assembly includes a pulley bracket, a pulley and a pulley shaft. There are two pulley brackets, which are installed on the top plate of the loading platform. The pulley is installed on the pulley bracket through the pulley shaft and fasteners. One end of the steel wire rope is thickened and protruded, and the other end has a threaded connecting rod. The thickened end of the steel wire rope is fixed to the tower pulley and wound along the conical groove of the tower pulley. It is then guided by two pulleys, passes through the center hole of the top plate of the loading platform, and is fixed to the connecting block.

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