A ball screw life testing device

Abstract

This invention provides a ball screw life testing device, relating to the field of ball screw testing technology. The device includes a base plate with a limiting member at its upper end. The two ends of the ball screw to be tested are mounted on the limiting member via bearings. A driving unit is provided on the base plate, which drives the ball screw to intermittently rotate forward and backward. During the rotation of the ball screw, a moving seat slides on the surface of the base plate, thereby achieving the test of the ball screw's lifespan under extreme conditions. This invention, by using the driving unit to drive the ball screw to achieve intermittent forward and reverse rotation, and then driving the moving seat to slide back and forth along the length of the base plate, can reproduce the extreme working conditions of frequent reversing and continuous reciprocating motion of the ball screw in actual applications. This avoids the problem of large deviations between the test results and the actual lifespan caused by the inaccurate simulation of working conditions in traditional testing devices, providing reliable data support for ball screw life assessment.

Description

Technical Field

[0001] This utility model relates to the field of ball screw testing technology, and in particular to a ball screw life testing device. Background Technology

[0002] As a core component of precision transmission, ball screws are widely used in CNC machine tools, automated production lines, industrial robots and precision instruments. Their service life directly determines the overall reliability, maintenance cycle and operating cost of the equipment. Therefore, conducting life testing on ball screws before leaving the factory or during use is a key step in ensuring the stable operation of downstream equipment and avoiding sudden failures.

[0003] Traditional testing devices can only drive the lead screw to rotate continuously in one direction to test the load-bearing and transmission capacity of the lead screw in a single direction. However, in actual scenarios, the lead screw often needs to frequently switch rotation directions according to the operating requirements of the equipment (such as CNC machine tool table positioning and robot joint movement) to achieve high-frequency and long-term reciprocating motion. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a ball screw life testing device.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a ball screw life testing device, comprising a horizontally arranged plate-shaped base plate, with limiting members symmetrically arranged at both ends of the upper end of the base plate along its length direction, the screw to be tested being mounted along the length direction of the base plate, and the two ends of the screw being rotatably connected to the limiting members at both ends by bearings respectively, a driving part being arranged at the upper end of the base plate near one of the limiting members, the driving part driving the screw to intermittently rotate forward and backward around its own axis through a transmission structure, a movable seat being sleeved on the outside of the screw and threadedly engaged with it in real time, the movable seat slidingly engaged with the surface of the base plate, when the screw intermittently rotates forward and backward, its surface thread drives the movable seat to slide back and forth along the length direction of the base plate to simulate the operating state of the screw under extreme working conditions, thereby realizing the detection of the screw life.

[0006] Preferably, the limiting component includes a mounting base vertically fixed to the upper end of the substrate, two parallel vertical rods vertically fixed to the mounting base facing the lead screw, and a lead screw horizontally rotatably connected to the mounting base facing the lead screw. The axis of the lead screw is perpendicular to the axis of the vertical rods, and the lead screw is located between the two vertical rods. The surface of the lead screw has external threads with opposite directions from its middle part to both ends, and two clamping arms are installed on the outer thread of the lead screw. The two clamping arms are slidably engaged with the two vertical rods respectively, and the side of the clamping arms facing the lead screw corresponds to the outer ring of the bearing. When the lead screw is rotated, the two clamping arms slide synchronously towards each other along the length of the vertical rod under the drive of the lead screw thread until they fit against the outer ring of the bearing and clamp and fix it, thereby limiting and fixing the lead screw above the substrate.

[0007] Preferably, an elastic rubber pad is fixedly bonded to the end face of the clamping arm facing the bearing. The size of the rubber pad is adapted to the end face of the clamping arm. When the two clamping arms slide towards each other to fit the outer ring of the bearing, the rubber pad is squeezed by the bearing and undergoes elastic deformation. The deformed rubber pad tightly wraps the surface of the outer ring of the bearing to enhance the clamping friction and avoid excessive clamping force that could damage the bearing.

[0008] Preferably, the end of the lead screw away from the mounting base passes through the clamping arm and extends to the outside of the clamping arm, and a regular hexagonal prism-shaped screw block is coaxially fixedly connected to the extended end of the lead screw. The outer diameter of the screw block is larger than the outer diameter of the lead screw. When the operator holds the screw block and applies rotational force, the lead screw can be driven to rotate around its own axis, thereby reducing the difficulty of operating the lead screw.

[0009] Preferably, the lead screw is fitted with a threaded sleeve whose internal thread matches the external thread of the lead screw. A bent plate-shaped connecting frame is provided between the threaded sleeve and the movable seat. One end of the connecting frame is fixed to the outer peripheral wall of the threaded sleeve by bolts, and the other end is fixed to the side wall of the movable seat facing the lead screw by bolts. When the lead screw rotates, the threaded sleeve moves along the axis of the lead screw under the drive of the lead screw thread, and then drives the movable seat to slide synchronously along the surface of the base plate through the connecting frame, so as to realize the stable transmission of the threaded motion to the linear motion.

[0010] Preferably, a rectangular guide groove is formed on the upper end surface of the substrate along its length direction. A slider adapted to the guide groove is integrally formed on the lower end of the movable seat. The slider is embedded in the guide groove. Two parallel and horizontal guide rods are also fixed on the upper end surface of the substrate. The axis of the guide rod is parallel to the axis of the lead screw, and the two guide rods are symmetrically distributed on both sides of the lead screw. A guide hole adapted to the guide rod is formed on the movable seat. The guide rod passes through the guide hole. When the movable seat slides, the slider slides along the inner wall of the guide groove, and the guide rod slides along the inner wall of the guide hole. The two together restrict the sliding direction of the movable seat and prevent the movable seat from deviating or shaking.

[0011] Preferably, the drive unit includes a stepper motor vertically fixed to the upper surface of the base plate via a motor mount, a first pulley coaxially fixed to the outer peripheral wall of the lead screw near the stepper motor end, and a second pulley coaxially fixed to the end of the stepper motor output shaft. The first pulley and the second pulley have the same specifications, and an annular synchronous belt is sleeved between them. The teeth on the inner peripheral wall of the synchronous belt mesh with the teeth on the outer peripheral walls of the first pulley and the second pulley. After the stepper motor starts, its output shaft drives the second pulley to rotate. The second pulley drives the first pulley to rotate synchronously through the meshing of the teeth of the synchronous belt, thereby driving the lead screw to rotate around its own axis. By controlling the forward and reverse rotation interval of the stepper motor, the intermittent forward and reverse rotation of the lead screw can be achieved.

[0012] Compared with the prior art, the advantages and positive effects of this utility model are as follows: In this invention, the device drives the lead screw to achieve intermittent forward and reverse rotation through the drive unit, thereby driving the moving seat to slide back and forth along the length of the base plate. This can reproduce the extreme working conditions of the lead screw frequently changing direction and continuously reciprocating in actual applications, avoiding the problem of large deviation between the test results and the actual life due to the non-fit of the working condition simulation of traditional testing devices, and providing reliable data support for lead screw life assessment. Attached Figure Description

[0013] Figure 1 This utility model provides a three-dimensional structural schematic diagram of a ball screw life detection device; Figure 2 This utility model presents another structural schematic diagram of a ball screw life detection device; Figure 3 This utility model proposes a ball screw life testing device. Figure 1 Enlarged view of point A.

[0014] Legend: 1. Base plate; 2. Mounting seat; 3. Vertical rod; 4. Sliding seat; 5. Clamping arm; 6. Rubber pad; 7. Lead screw; 8. Tightening block; 9. Bearing; 10. Lead screw; 11. Threaded sleeve; 12. Moving seat; 13. Guide groove; 14. Guide rod; 15. First pulley; 16. Stepper motor; 17. Second pulley; 18. Synchronous belt. Detailed Implementation

[0015] Example 1, as Figure 1-3As shown, a ball screw life testing device includes a horizontally placed plate-shaped base plate 1. The base plate 1 is made of high-strength aluminum alloy to ensure the stability of the overall structure. Limiting components are symmetrically arranged at both ends of the upper end of the base plate 1 along its length. The ball screw 10 to be tested is mounted along the length of the base plate 1, and the two ends of the ball screw 10 are rotatably connected to the limiting components at both ends through deep groove ball bearings 9. The inner ring of the deep groove ball bearing 9 is interference-fitted with the end of the ball screw 10, and the outer ring is correspondingly adapted to the limiting components. A drive unit is arranged at the upper end of the base plate 1 near one of the limiting components. The drive unit drives the ball screw 10 to intermittently rotate forward and reverse around its own axis through a synchronous belt 18 transmission structure. The stepper motor 16 used in the drive unit is a model whose speed and forward and reverse interval can be adjusted by an external controller to meet the simulation requirements of different extreme working conditions. A movable seat 12, which is threadedly fitted to the outer side of the lead screw 10, is made of metal and its lower end face is smoothed with respect to the upper surface of the substrate 1 to reduce sliding friction resistance. The movable seat 12 maintains a sliding fit with the surface of the substrate 1. When the lead screw 10 is driven by the drive unit to perform intermittent forward and reverse rotation, the external thread on its surface drives the movable seat 12 to reciprocate along the length of the substrate 1. This reciprocating sliding simulates the extreme operating conditions of the lead screw 10 in actual applications, thereby enabling the detection of the service life of the lead screw 10.

[0016] like Figure 1-3As shown, the limiting component includes a mounting base 2 vertically fixed to the upper end of the base plate 1. The mounting base 2 and the base plate 1 are made of the same aluminum alloy and are fixedly connected by bolts to ensure the connection strength. The limiting component also includes two parallel and vertically fixed vertical rods 3 on the end face of the mounting base 2 facing the lead screw 10. The vertical rods 3 are made of metal round rods and are connected to the mounting base 2 by welding or bolting. The limiting component also includes a lead screw 7 horizontally rotatably connected to the end face of the mounting base 2 facing the lead screw 10. The lead screw 7 and the mounting base 2 are rotated together by a rolling bearing 9 to reduce rotational resistance. The axis of the lead screw 7 is perpendicular to the axis of the vertical rod 3, and the lead screw 7 is located in the middle between the two vertical rods 3. The surface of the lead screw 7 has external threads with opposite directions of rotation from the middle to both ends. Specifically, the left side of the middle of the lead screw 7 has a right-hand thread and the right side has a left-hand thread. Two clamping arms 5 are installed on the outer threads of the lead screw 7. Both clamping arms 5 are made of metal sheet and have sliding holes on their side walls that are adapted to the vertical rods 3. The two clamping arms 5 slide with the two vertical rods 3 through the sliding holes. The end face of the clamping arm 5 facing the lead screw 10 is machined with an arc-shaped groove adapted to the outer ring of the bearing 9 to improve the clamping stability of the bearing 9. When the lead screw 7 is rotated, the two clamping arms 5 will slide synchronously towards each other along the length of the vertical rod 3 under the drive of the different directions of rotation of the lead screw 7, until the arc-shaped groove on the end face of the clamping arm 5 fits against the outer ring of the bearing 9 and forms a stable clamping and fixing, thereby stably limiting and fixing the lead screw 10 to a preset position above the base plate 1.

[0017] like Figure 1-3 As shown, an elastic rubber pad 6 is fixedly bonded to the end face of the clamping arm 5 facing the bearing 9 using strong adhesive. The pad 6 is made of nitrile rubber to combine good elasticity and wear resistance. The size of the pad 6 is perfectly matched to the size of the end face of the clamping arm 5 facing the bearing 9, and the surface of the pad 6 is roughened to improve the coefficient of friction. When the two clamping arms 5 slide towards each other until they are in contact with the outer ring of the bearing 9, the pad 6 will undergo elastic deformation under the compression of the outer ring of the bearing 9. The deformed pad 6 will tightly wrap around the surface of the outer ring of the bearing 9. On the one hand, this can significantly enhance the friction between the clamping arm 5 and the bearing 9 to prevent the bearing 9 from loosening during the testing process. On the other hand, the elastic buffer of the pad 6 can prevent excessive clamping force from damaging the outer ring of the bearing 9.

[0018] like Figure 1-3As shown, the end of the lead screw 7 furthest from the mounting base 2 passes through the clamping arm 5 and extends to the outside of the clamping arm 5. A hexagonal prism-shaped screw block 8 is coaxially fixed to the extended end of the lead screw 7 via a key connection. The screw block 8 is made of metal to ensure sufficient strength. The outer diameter of the screw block 8 is larger than the outer diameter of the lead screw 7, and its outer surface is treated with an anti-slip coating for easy gripping by the operator. When adjusting the position of the clamping arm 5, the operator can directly grasp the screw block 8 and apply rotational force. The screw block 8 drives the lead screw 7 to rotate around its own axis, completing the adjustment operation without the need for additional tools, effectively reducing the difficulty of adjusting the rotation of the lead screw 7.

[0019] like Figure 1-3 As shown, a threaded sleeve 11 with an internal thread that matches the external thread of the lead screw 10 is fitted on the outer side of the lead screw 10. The threaded sleeve 11 is made of metal, and the clearance between its internal thread and the external thread of the lead screw 10 is controlled within a small range to ensure transmission accuracy. A bent plate-shaped connecting frame is provided between the threaded sleeve 11 and the moving seat 12. The connecting frame is made of steel plate of appropriate thickness to have sufficient structural strength. One end of the connecting frame is fixedly connected to the outer peripheral wall of the threaded sleeve 11 by two hexagonal socket head cap screws. The number of bolts is set to two and they are symmetrically distributed to ensure the stability of the connection. The other end of the connecting frame is also fixedly connected to the side wall of the moving seat 12 facing the lead screw 10 by hexagonal socket head cap screws. The connection parts are reinforced to prevent loosening during long-term use. When the lead screw 10 rotates under the drive of the drive unit, the threaded sleeve 11 will reciprocate along the axis of the lead screw 10 under the drive of the external thread of the lead screw 10, and then drive the moving seat 12 to slide synchronously along the surface of the base plate 1 through the connecting frame. This connection method can realize the stable transmission of threaded motion to linear motion, and there will be no relative sliding between the threaded sleeve 11 and the moving seat 12.

[0020] like Figure 1-3As shown, a rectangular guide groove 13 is formed along the length of the upper surface of the substrate 1. The width of the guide groove 13 is adapted to the width of the slider at the lower end of the movable seat 12, and the groove wall is smoothed to ensure smooth sliding. A slider adapted to the guide groove 13 is integrally formed at the lower end of the movable seat 12. The slider is made of metal and its thickness is adapted to the depth of the guide groove 13. The slider is embedded in the guide groove 13 and maintains a small fit clearance with the groove wall of the guide groove 13. Two parallel and horizontal guide rods 14 are also fixed to the upper surface of the substrate 1 by bolts. The guide rods 14 are made of high-strength metal round rods and their surfaces are chrome-plated to improve wear resistance. The axis of the guide rods 14 is parallel to the axis of the lead screw 10, and the two guide rods 14 are symmetrically distributed on both sides of the lead screw 10 to ensure force balance. A guide hole adapted to the guide rod 14 is formed on the movable seat 12. The inner wall of the guide hole is smoothed to reduce sliding resistance. The guide rod 14 passes through the guide hole and maintains a smooth sliding fit with the inner wall of the guide hole. When the movable seat 12 slides under the drive of the lead screw 10, the slider at the lower end of the movable seat 12 will slide along the inner wall of the guide groove 13, and at the same time the guide rod 14 will slide along the inner wall of the guide hole on the movable seat 12. The two work together to limit the sliding direction of the movable seat 12, effectively preventing the movable seat 12 from deviating or shaking during the sliding process.

[0021] like Figure 1-3 As shown, the drive unit includes a stepper motor 16 vertically fixed to the upper surface of the base plate 1 via a motor mount. The motor mount adopts a metal bracket structure and is fixedly connected to the base plate 1 with bolts to improve the stability of the stepper motor 16 installation. The drive unit also includes a first pulley 15 coaxially fixed to the outer peripheral wall of the lead screw 10 near the end of the stepper motor 16. The first pulley 15 is fixedly connected to the lead screw 10 via a flat key to ensure no relative slippage during transmission. The drive unit also includes a second pulley 17 coaxially fixed to the end of the output shaft of the stepper motor 16. The second pulley 17 is also fixedly connected to the output shaft of the stepper motor 16 via a flat key. The first pulley 15 and the second pulley 17 have the same number of teeth, pitch circle diameter, and other specifications to ensure a transmission ratio of 1. An annular synchronous belt 18 is sleeved between them. The synchronous belt 18 is made of rubber material with embedded fiber core to improve tensile strength. The teeth on the inner peripheral wall of the synchronous belt 18 precisely mesh with the teeth on the outer peripheral walls of the first pulley 15 and the second pulley 17 to avoid slippage during transmission. After the stepper motor 16 is started, its output shaft will drive the second pulley 17 to rotate around its own axis. The second pulley 17 drives the first pulley 15 to rotate synchronously through the tooth meshing of the synchronous belt 18. In turn, the first pulley 15 drives the lead screw 10 to rotate around its own axis. By setting the forward and reverse rotation interval of the stepper motor 16 through an external controller, the lead screw 10 can be made to perform intermittent forward and reverse rotation according to a preset frequency.

[0022] Working principle: Before testing the life of the ball screw 10, the bearings 9 at both ends of the screw 10 to be tested are placed between the two clamping arms 5 of the limiting members at both ends of the base plate 1. Then, the operator holds the screw block 8 on the limiting member and applies a rotational force. The screw block 8 drives the screw 7 to rotate around its own axis. Since the threads on the surface of the screw 7 rotate in opposite directions from the middle to both ends, the two clamping arms 5 will slide synchronously towards each other along the vertical rod 3 under the drive of the screw 7 threads until the rubber pad 6 on the end face of the clamping arm 5 is in contact with the outer ring of the bearing 9. The screw block 8 is rotated to make the rubber pad 6 be squeezed and elastically deformed. The deformed rubber pad 6 tightly wraps the outer ring of the bearing 9, thereby stably fixing the screw 10 in the preset position above the base plate 1. During testing, the stepper motor 16 of the drive unit is activated. The output shaft of the stepper motor 16 drives the second pulley 17 to rotate. The second pulley 17 transmits power to the first pulley 15 through the synchronous belt 18 that meshes with its teeth. The first pulley 15 drives the lead screw 10 to rotate around its own axis. The operating parameters of the stepper motor 16 are adjusted by an external controller, so that the stepper motor 16 rotates forward and reverse at preset intervals, thereby driving the lead screw 10 to achieve intermittent forward and reverse rotation. During the rotation of the lead screw 10, the external thread on its surface drives the threaded sleeve 11, which is sleeved on the outside, to move along the axis of the lead screw 10. The threaded sleeve 11 drives the moving seat 12 to move synchronously through the connecting frame. At this time, the slider at the lower end of the moving seat 12 slides along the guide groove 13 on the base plate 1, and at the same time, the guide rod 14 on the base plate 1 slides along the guide hole of the moving seat 12. Under the combined limiting action of the guide groove 13 and the guide rod 14, the moving seat 12 always slides linearly back and forth along the length direction of the base plate 1. The reciprocating sliding of the movable seat 12 simulates the extreme working conditions of the lead screw 10 in actual applications. The lead screw 10 is kept in this operating state until the lead screw 10 experiences faults such as jamming, abnormal noise, or decreased transmission accuracy. The cumulative running time and number of reciprocating movements of the lead screw 10 from start-up to the occurrence of fault are recorded, thus completing the life test of the lead screw 10.

[0023] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may use the disclosed technical content to make changes or modifications to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model, without departing from the scope of the utility model's technical solution, still fall within the protection scope of this utility model's technical solution. In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood through specific circumstances.

Claims

1. A ball screw life detection device comprising a substrate (1), characterized in that: The upper end of the substrate (1) is provided with a limiting member. The two ends of the lead screw (10) to be tested are mounted on the limiting member by means of bearings (9). The substrate (1) is provided with a driving part, which can drive the lead screw (10) to rotate intermittently in both directions. During the rotation of the lead screw (10), the moving seat (12) is driven to slide on the surface of the substrate (1) to achieve the test of the lead screw (10) under extreme conditions.

2. The ball screw life detection device according to claim 1, characterized by: The limiting component includes a mounting base (2), a vertical rod (3), and a lead screw (7). The vertical rod (3) and the mounting base (2) are fixed, and the lead screw (7) and the mounting base (2) are rotatably connected. Two clamping arms (5) are threaded on the surface of the lead screw (7), and a sliding seat (4) is fixedly connected to the clamping arms (5). The thread direction on the surface of the lead screw (7) is symmetrical and opposite from the middle. Rotating the lead screw (7) drives the two clamping arms (5) to slide and clamp the bearing (9) on the surface of the vertical rod (3) with the help of the sliding seat (4) to fix the lead screw (10).

3. The ball screw life detection device according to claim 2, characterized by: The clamping arms (5) are fixedly connected to a rubber pad (6) at one end that is close to each other. When the two clamping arms (5) are close to each other and clamp the bearing (9), the rubber pad (6) deforms and fixes the bearing (9).

4. The ball screw life detection device according to claim 2, characterized by: The upper end of the lead screw (7) passes through the clamping arm (5), and a screw block (8) is fixedly connected to one end of the lead screw (7) extending out of the clamping arm (5). The lead screw (7) is rotated by rotating the screw block (8).

5. The ball screw life testing device according to claim 1, characterized in that: The lead screw (10) is threaded with a threaded sleeve (11), and a connecting frame is installed between the threaded sleeve (11) and the moving seat (12). The connecting frame is fixed between the threaded sleeve (11) and the moving seat (12) by means of bolts.

6. The ball screw life detection device of claim 1, wherein: The upper end of the substrate (1) is provided with a guide groove (13), the movable seat (12) slides inside the guide groove (13), and the upper end of the substrate (1) is fixedly connected with a guide rod (14), which slides between the guide rod (14) and the movable seat (12).

7. The ball screw life detection device of claim 1, wherein: The drive unit includes a stepper motor (16) fixedly mounted on the upper end of the base plate (1), and also includes a first pulley (15) and a second pulley (17). The first pulley (15) is mounted on the surface of the lead screw (10), and the second pulley (17) is mounted on the output shaft of the stepper motor (16). The first pulley (15) and the second pulley (17) are driven by a synchronous belt (18).

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