A ball screw pair axial clearance measuring device

Abstract

This utility model discloses a ball screw pair axial backlash measuring device, including a worktable, outer guide rails, inner guide rails, a left slide block, a right slide block, a middle slide block, a left pulley, a right pulley, a left pull rope, and a right pull rope. The outer guide rails are symmetrically mounted on the worktable. The inner guide rails are symmetrically mounted on the worktable. The left and right slide blocks are both mounted on the two outer guide rails. The middle slide block is mounted on the two inner guide rails. The left pulley is mounted at the left end of the worktable. The right pulley is mounted at the right end of the worktable. The left pull rope is draped over the left pulley, and one end of the left pull rope is detachably connected to the left side of the middle slide block or detachably connected to the left slide block. The right pull rope is draped over the right pulley, and one end of the right pull rope is detachably connected to the right side of the middle slide block or detachably connected to the right slide block. This utility model can stably apply bidirectional axial loads, reduce slide block movement interference, and adapt to different specifications of ball screws.

Description

Technical Field

[0001] This utility model belongs to the field of ball screw pair technology, and in particular relates to a ball screw pair axial clearance measuring device. Background Technology

[0002] Ball screw pairs, as high-precision transmission components, are widely used in machine tools, automobiles, and aerospace fields. The measurement of their axial clearance directly determines the positioning accuracy and service life of the equipment. In existing technology, a typical detection device, as described in patent CN 115508086 A, uses a linear guide pair as its core structure, aiming to achieve bidirectional axial clearance measurement through a weight loading system. This device includes a worktable, a linear guide pair mounted on the worktable, a first and second support (for fixing the ball screw) set on the guide rail, and a sliding support (fixed to the ball nut) located between the two supports. The loading mechanism consists of a wire rope, a reversing wheel, and suspended weights. The wire rope is wound around a slip mechanism, extends vertically below the worktable via the reversing wheel, and the weights are detachably connected to an anti-slip ring via hooks, enabling alternating forward and reverse loading. The lead screw is fixed by a pair of coaxial centers pressing against both ends of the lead screw and locking it with a fastening mechanism to reduce relative rotation; the sliding support moves along the guide rail under the pulling force of the weight, causing the nut to move, and the displacement is measured by a dial indicator to obtain the axial clearance.

[0003] Although this technology reduces some errors through gravity loading and bidirectional clamping mechanism, it relies on a single linear guide pair. All slides (including the support for fixing the lead screw and the sliding support for bearing the nut) are integrated on the same guide rail. The movement of the slides is prone to mutual interference, causing the lead screw to rotate slightly or shift laterally during loading. In addition, adjusting the lead screw of different lengths requires frequent sliding of the support position and locking through the fastening mechanism. The operation is cumbersome and cannot completely eliminate the displacement deviation introduced by the guide rail friction, affecting the measurement accuracy of micron-level gaps.

[0004] Therefore, there is an urgent need for a detection device that can stably apply bidirectional axial loads, reduce slide movement interference, and adapt to lead screws of different specifications, in order to solve the problem of insufficient accuracy of measurement results caused by system coupling errors. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a ball screw pair axial clearance measuring device to address the shortcomings of the prior art and solve the problem of insufficient accuracy of the measurement results caused by system coupling error.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a ball screw pair axial clearance measuring device, including a worktable, an outer guide rail, an inner guide rail, a left slide, a right slide, a middle slide, a left pulley, a right pulley, a left pull rope, and a right pull rope; The outer guide rail is provided in two parts, and the two outer guide rails are symmetrically mounted on the worktable. The inner guide rail has two inner guide rails, which are symmetrically mounted on the worktable and located inside the two outer guide rails. Both the left and right slide blocks are mounted on the two outer guide rails and can slide left and right along the outer guide rails; The middle slide block is mounted on the two inner guide rails and can slide left and right along the inner guide rails; The left pulley is installed at the left end of the workbench; The right pulley is installed at the right end of the workbench; The left pull rope is laid on the left pulley, and one end of the left pull rope can be detachably connected to the left side of the middle slide block or detachably connected to the left slide block; The right pull rope is laid on the right pulley, and one end of the right pull rope can be detachably connected to the right side of the middle slide block or detachably connected to the right slide block.

[0007] The aforementioned ball screw pair axial clearance measuring device has hooks at the other ends of both the left and right pull ropes, which are used to hang counterweights.

[0008] The aforementioned ball screw pair axial clearance measuring device has a clamping fixture on the middle slide, which is used to clamp the nut of the ball screw pair.

[0009] The aforementioned ball screw pair axial clearance measuring device has a top pin fixture on both the left and right slides, and the two top pin fixtures are used to clamp the two ends of the ball screw pair.

[0010] In the aforementioned ball screw pair axial clearance measuring device, when one end of the left pull rope and the right pull rope are detachably connected to the left slide and the right slide respectively, the tension direction of the left pull rope and the right pull rope is coaxial with the axis of the screw. In the aforementioned ball screw pair axial clearance measuring device, guide seats are provided on both the left and right sides of the worktable. The guide seats have guide holes, and the hanging ends of the left and right pull ropes pass through the guide holes on their respective guide seats. This utility model has the following advantages compared with the prior art: 1. The outer guide rails support the left and right slides respectively, while the inner guide rail independently supports the middle slide, achieving physical isolation of the slide movement path. This layout avoids mutual interference caused by uneven frictional resistance among multiple slides in traditional single-guide rail systems. It is particularly effective in addressing the off-center loading problem caused by the weight of the long lead screw during measurement, significantly improving the stability of slide movement and ensuring the accuracy of data collected by displacement sensors (such as dial indicators).

[0011] 2. The left and right pull ropes are connected to the central slide (simulating nut displacement) or the left / right slide (simulating lead screw displacement) via pulleys, and feature a detachable design (such as hooks or clips). This structure overcomes the limitations of traditional fixed loading mechanisms (such as cylinders and weights applying force in one direction), allowing for quick switching of the force application object based on the specifications of the ball screw pair being tested (such as lead screw length and nut size). Short lead screw: The pull rope is directly connected to the left / right slide block, applying force to both ends of the lead screw; Long lead screw: The pull rope is replaced with a middle slide block to apply force to the nut.

[0012] 3. The left and right pull ropes are alternately pulled by a pulley mechanism, which can apply bidirectional axial tension to the test piece, accurately simulating the bidirectional force scenario under actual working conditions. Compared with unidirectional loading devices, this design can simultaneously capture positive and negative clearance errors, avoid measurement deviations caused by unidirectional force, and improve the comprehensiveness and reliability of clearance data.

[0013] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the main structure of this utility model.

[0015] Figure 2 This is a top view of the structure of this utility model.

[0016] Figure 3 This is a schematic diagram of the left-side structure of this utility model.

[0017] Figure 4 This is a schematic diagram of the clamping fixture of this utility model.

[0018] Explanation of reference numerals in the attached figures: Detailed Implementation

[0019] like Figure 1 — Figure 4 As shown, a ball screw pair axial clearance measuring device includes a worktable 1, an outer guide rail 2, an inner guide rail 3, a left slide 4, a right slide 5, a middle slide 6, a left pulley 7, a right pulley 8, a left pull rope 9, and a right pull rope 10. There are two outer guide rails 2, and the two outer guide rails 2 are symmetrically installed on the worktable 1; There are two inner guide rails 3, which are symmetrically installed on the worktable 1 and located inside the two outer guide rails 2. The left slide block 4 and the right slide block 5 are both mounted on the two outer guide rails 2 and can slide left and right along the outer guide rails 2; The middle slide block 6 is mounted on the two inner guide rails 3 and can slide left and right along the inner guide rails 3; The left pulley 7 is installed at the left end of the workbench 1; The right pulley 8 is installed at the right end of the workbench 1; The left pull rope 9 is laid on the left pulley 7, and one end of the left pull rope 9 can be detachably connected to the left side of the middle slide block 6 or detachably connected to the left slide block 4; The right pull rope 10 is mounted on the right pulley 8, and one end of the right pull rope 10 can be detachably connected to the right side of the middle slide block 6 or detachably connected to the right slide block 5.

[0020] It should be noted that the spacing of the outer guide rail 2 is greater than that of the inner guide rail 3. For example, the spacing of the outer guide rail 2 is matched to the length of the lead screw (500–2000 mm), and the spacing of the inner guide rail 3 is 60%–70% of that of the outer guide rail 2 to avoid motion interference. When the pull rope is connected to the middle slide block 6, the left and right pull ropes alternately pull the nut to move in the forward and reverse directions (e.g., adding weight to the left pull rope 9 → the nut moves to the left; adding weight to the right pull rope 10 → the nut moves to the right). When the pull rope connects the left / right slide block 5, the ends of the slide block and the lead screw are fixed, and the pull rope applies a coaxial tension to both ends of the lead screw (e.g., the left pull rope 9 pulls the left slide block 4 → the lead screw is subjected to a leftward tension), eliminating the non-axial component force.

[0021] The separate design of the inner and outer guide rails avoids load interference and ensures the independence of the screw fixing and nut movement; the pull rope switching mechanism adapts to different measurement needs (directly measuring nut displacement or indirectly measuring screw axial movement).

[0022] In this embodiment, the other end of both the left pull rope 9 and the right pull rope 10 has a hook, which is used to hang the counterweight 11.

[0023] The counterweight 11 is graded according to standard mass (e.g., 1kg / 5kg). For example, when measuring a small lead screw (20mm in diameter), the initial load is 5kg, and when measuring a large lead screw (50mm in diameter), the load is 20kg. The hook and the anti-detachment pull ring work together to prevent the weight from falling off. The counterweight 11 achieves constant force loading, avoiding the problem of unstable force value caused by air pressure or voltage fluctuations in cylinder / motor drive.

[0024] In this embodiment, the middle slide 6 has a clamping fixture 12 for clamping the nut of the ball screw assembly. The middle slide 6 is equipped with the clamping fixture 12 (such as a chuck or V-block) to fix the nut. This restricts the rotation of the nut, ensuring that only axial displacement is measured (a core condition for defining the clearance of the ball screw assembly). The clamping force is adjusted by a handle or cylinder to avoid overpressure damaging the nut surface.

[0025] In this embodiment, both the left slide block 4 and the right slide block 5 have a top pin fixture 13, and the two top pin fixtures 13 are used to clamp the two ends of the ball screw pair.

[0026] It should be noted that the conical surface of the top pin of the top pin tool 13 is inserted into the center hole of the lead screw, and a keyway is provided between the top pin and the slide (e.g., the slide key is embedded in the groove of the top pin), which allows for axial fine adjustment to accommodate different lead screw lengths.

[0027] In this embodiment, when one end of the left pull rope 9 and the right pull rope 10 are detachably connected to the left slide block 4 and the right slide block 5 respectively, the pulling direction of the left pull rope 9 and the right pull rope 10 is coaxial with the axis of the lead screw.

[0028] When the pull rope connects to the left / right slide block 5, the direction of the pulling force is coaxial with the screw axis, which can eliminate the lateral component force and solve the error caused by the screw's own weight sagging in traditional transverse measurements (especially for screws with a length-to-diameter ratio > 30). In implementation: the guide seat 14 is equipped with a coaxial positioning hole (e.g., the hole diameter is slightly larger than the pull rope diameter), forcing the pull rope path to be parallel to the screw axis; laser calibration ensures that the pulley, guide hole, and screw axes are aligned (deviation < 0.1 mm / m).

[0029] In this embodiment, guide seats 14 are provided on both the left and right sides of the workbench 1. The guide seats 14 have guide holes, and the hanging ends of the left pull rope 9 and the right pull rope 10 pass through the guide holes on their respective guide seats 14.

[0030] Guide seats 14 are provided on both sides of the workbench 1. The guide holes constrain the hanging end of the pull rope, which can keep the pull rope vertical and prevent the weight from swinging and affecting the stability of the loading force. The guide holes are lined with polytetrafluoroethylene bushings to reduce friction and ensure that the weight falls freely.

[0031] In use, the left slide 4 is fixed to the outer guide rail 2 by the set screw on the left slide 4. Then, the right slide 5 is slid left and right to a suitable position so that the set screw 13 on the two slides clamps the ball screw pair between the two slides. Then, the right slide 5 is fixed to the outer guide rail 2 by the set screw. The middle slide 6 is adjusted to be clamped on the nut or supported on one end of the nut. Finally, the middle slide 6 is pulled by adding a counterweight 11 to the pull rope. Then, the sliding of the middle slide 6 applies axial force to the nut to measure the axial clearance.

[0032] Another method of using this utility model is to clamp the nut with the middle slide block 6, and then fix the middle slide block 6 on the inner guide rail with the set screw. The set screw fixture 13 and the end of the lead screw are welded together. The left slide block 4 is pulled by the left pull rope 9, which moves the lead screw to the left axial direction to measure the axial clearance. The right slide block 5 is pulled by the right pull rope 10, which moves the lead screw to the right axial direction to measure the axial clearance.

[0033] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the present utility model. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present utility model shall still fall within the protection scope of the present utility model.

Claims

1. A device for measuring the axial clearance of a ball screw pair, characterized in that, Includes a worktable, outer guide rail, inner guide rail, left slide block, right slide block, middle slide block, left pulley, right pulley, left pull rope, and right pull rope; The outer guide rail is provided in two parts, and the two outer guide rails are symmetrically mounted on the worktable. The inner guide rail has two inner guide rails, which are symmetrically mounted on the worktable and located inside the two outer guide rails. Both the left and right slide blocks are mounted on the two outer guide rails and can slide left and right along the outer guide rails; The middle slide block is mounted on the two inner guide rails and can slide left and right along the inner guide rails; The left pulley is installed at the left end of the workbench; The right pulley is installed at the right end of the workbench; The left pull rope is laid on the left pulley, and one end of the left pull rope can be detachably connected to the left side of the middle slide block or detachably connected to the left slide block; The right pull rope is laid on the right pulley, and one end of the right pull rope can be detachably connected to the right side of the middle slide block or detachably connected to the right slide block.

2. The axial clearance measuring device for a ball screw pair according to claim 1, characterized in that, Both the left and right pull ropes have hooks at the other end, which are used to hang counterweights.

3. The axial clearance measuring device for a ball screw pair according to claim 1, characterized in that, The middle slide has a clamping fixture for clamping the nut of the ball screw assembly.

4. The axial clearance measuring device for a ball screw pair according to claim 1, characterized in that, Both the left and right slides have top pins, and the two top pins are used to clamp the two ends of the ball screw assembly.

5. The axial clearance measuring device for a ball screw pair according to claim 4, characterized in that, When one end of the left pull rope and the right pull rope are detachably connected to the left slide block and the right slide block respectively, the direction of the tension of the left pull rope and the right pull rope is coaxial with the axis of the lead screw.

6. The axial clearance measuring device for a ball screw pair according to claim 1, characterized in that, Guide seats are provided on both the left and right sides of the workbench. Each guide seat has a guide hole, and the hanging ends of the left and right pull ropes pass through the guide holes on their respective guide seats.

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