Micro-screw pair axial play detection device and detection method

Abstract

This invention belongs to the field of miniature ball screw pair measurement technology, and discloses a device and method for detecting axial clearance of miniature ball screw pairs. The device includes a support frame and a nut fixing mechanism, a screw clamping mechanism, a loading mechanism, and a displacement measuring mechanism mounted on the support frame. Addressing the challenge of detecting the small size and micrometer-level clearance of miniature ball screw pairs, this invention adopts a vertically arranged structural layout. The lower limit position is located by the screw's own weight, and the upper limit position is located through the cooperation of the screw clamping mechanism and the loading mechanism. The displacement measuring mechanism directly obtains the displacement of the upper end of the screw at the two limit positions, enabling precise measurement of micrometer-level axial clearance. This avoids errors caused by indirect measurement. The overall structural layout is simple, reducing deformation and thermal errors caused by redundant structures, and effectively improving both detection accuracy and efficiency.

Description

Technical Field

[0001] This invention relates to the field of miniature ball screw pair measurement technology, and in particular to a device and method for detecting axial clearance of miniature ball screw pairs. Background Technology

[0002] A ball screw pair (or simply screw pair) consists of a screw, a nut, and steel balls disposed in the gap between the screw and the nut. The steel balls roll within the raceways of the screw and the nut, achieving the conversion between rotary and linear motion through helical transmission. The axial clearance between the screw and the nut is an important quality parameter for measuring the transmission accuracy, reverse sensitivity, and positioning accuracy of the screw pair. Especially in applications such as precision feeding, semiconductors, and medical devices, the consistency requirements for axial clearance are extremely high.

[0003] Patent CN116007476A discloses a ball screw backlash detection device. This device uses a nut chuck to clamp the nut around the outer circumference of the product under test. A threaded rod passes laterally through the axial through-hole of the screw and is then fixed to a main support plate via a locking nut. A counterweight and lever are used to apply a pushing force to the main support plate, and the axial backlash is obtained by measuring the displacement of the threaded rod using a measuring pen. In this type of device, the screw is typically placed horizontally, the nut is clamped by a chuck, and the screw is rigidly connected to the locking nut via a threaded rod passing through its axial through-hole. The device measures the displacement of the threaded rod.

[0004] Patent CN119394242A discloses a ball screw axial clearance measuring device. It uses a top-down nut clamping structure and screw clamping structure to vertically position the nut and screw, and incorporates a universal floating structure to adjust the screw's center of gravity and a compensation structure to measure system deformation and improve accuracy. Furthermore, patent CN119394243A separately discloses a loading structure in this type of measuring device, employing an S-shaped spring force sensor, two sets of upper and lower force transmission springs, and an external plate for the clamping structure to smoothly apply the test force vertically. The purpose of this invention is to solve the problem of inaccurate measurements caused by the center of gravity shift when a long screw is placed laterally.

[0005] However, none of the aforementioned existing technologies are suitable for axial clearance detection of miniature lead screw pairs because miniature lead screw pairs have the following characteristics: First, the lead screw diameter is very small, and the clearance is on the order of micrometers (μm), making detection extremely difficult. The requirements for the centering, stiffness, and repeatability of the measurement configuration are much higher than those for ordinary lead screw pairs. Second, miniature lead screw pairs present significant challenges in fixing the lead screw and nut, as well as in controlling the clearance measurement accuracy. Third, miniature lead screw pairs are small in size and lightweight. If a complex vertical layout designed for long lead screws is adopted, it will not only introduce additional sources of deformation and thermal error but also reduce measurement accuracy, and the structure will be redundant and costly. Summary of the Invention

[0006] In view of the above problems, the purpose of this invention is to provide a device and method for detecting the axial clearance of a micro screw pair, so as to accurately measure the micron-level axial clearance of the micro screw pair.

[0007] To achieve this objective, the present invention employs the following technical solution: A device for detecting axial clearance of a miniature lead screw pair, the miniature lead screw pair including a threaded lead screw and a lead screw nut, the device including a support frame and a lead screw nut fixing mechanism, a lead screw clamping mechanism, a loading mechanism and a displacement measuring mechanism disposed on the support frame, wherein: The lead screw fixing mechanism includes a positioning seat and an adapter fixture. The adapter fixture is used to fix the lead screw and allow the lead screw to rotate freely relative to the lead screw. The positioning seat is used to fix the adapter fixture and keep the axis of the lead screw in the vertical direction. The lead screw clamping mechanism is used to clamp the lower end of the lead screw; The loading mechanism is used to apply a set vertical upward axial force to the clamped lead screw, so that the lead screw produces relative displacement with respect to the fixed lead nut. The displacement measuring mechanism is used to measure the displacement of the upper end of the lead screw, which is the axial clearance value of the miniature lead screw pair.

[0008] As an alternative, the positioning seat is provided with a positioning groove that matches the shape of the fitting tooling, and locking elements are provided on the positioning seat and on both sides of the positioning groove. The locking elements are used to lock and fix the fitting tooling inserted into the positioning groove onto the positioning seat.

[0009] As an alternative, the support frame is provided with a first linear guide rail extending vertically above the positioning seat. The displacement measuring mechanism includes a first slide and a displacement measuring component. The first slide is slidably disposed on the first linear guide rail. The displacement measuring component is mounted on the first slide and abuts against the upper end of the lead screw. The support frame is provided with a first lifting drive component for driving the first slide to move along the first linear guide rail.

[0010] As an alternative, the displacement measuring device uses a high-precision contact displacement sensor with a resolution of 0.1μm.

[0011] As an alternative, the support frame is provided with a first limiting member for limiting the range of movement of the first slide on the first linear guide rail.

[0012] As an optional solution, the front of the support frame is provided with a second linear guide rail extending vertically below the positioning seat. The screw clamping mechanism includes a lifting seat and a clamping component. The lifting seat is slidably mounted on the second linear guide rail. The clamping component is mounted on the side of the lifting seat facing the positioning seat. A rotary drive and a floating joint are provided on the side of the lifting seat facing away from the positioning seat. The rotary drive is used to drive the clamping component to rotate. A tension / compression sensor is provided at the output end of the loading mechanism. The tension / compression sensor is connected to the floating joint.

[0013] As an alternative, a first guide wheel is provided on the front of the support frame and between the positioning seat and the lifting seat. A second guide wheel corresponding to the first guide wheel and a vertically arranged third linear guide rail are provided on the back of the support frame. A counterweight frame is slidably mounted on the third linear guide rail. A chain passing through the support frame is wound around the first and second guide wheels. One end of the chain is connected to the positioning seat, and the other end of the chain is connected to the counterweight frame. The counterweight frame is provided with a counterweight block for offsetting the weight of the lead screw and the lead screw clamping mechanism.

[0014] As an optional solution, the loading mechanism includes a second slide and a loading drive. The second slide is slidably mounted on a second linear guide rail. The loading drive is mounted on the second slide and connected to a tension / compression sensor. A second lifting drive is provided on the support frame for driving the second slide to move along the second linear guide rail.

[0015] As an optional solution, the support frame is provided with a second limiting member to limit the range of movement of the lifting seat on the second linear guide rail.

[0016] On the other hand, the present invention adopts the following technical solution: A method for detecting axial backlash in a miniature lead screw pair, based on the aforementioned axial backlash detection device, includes the following steps: S1, fix the nut of the miniature lead screw pair to be tested on the adapter fixture, and then fix the adapter fixture on the positioning seat of the lead screw fixing mechanism so that the axis of the lead screw is in the vertical direction and the lead screw of the miniature lead screw pair can rotate freely relative to the lead screw. S2, adjust the relative position of the lead screw and the lead nut. At this time, the lead screw is in the lower limit position of the allowable movement due to the axial clearance between the lead screw and the lead nut under its own weight. Then control the lead screw clamping mechanism to clamp the lower end of the lead screw, and control the displacement measuring component of the displacement measuring mechanism to abut the upper end of the lead screw and complete the zeroing. S3 controls the loading mechanism to apply a set vertical upward axial force to the lead screw, so that the lead screw is in the upper limit position where it can move due to axial clearance. The displacement of the upper end of the lead screw is measured by the displacement measuring mechanism. The displacement is the axial clearance value of the miniature lead screw pair in the relative position.

[0017] The beneficial effects of this invention are: This device and method for detecting axial clearance of miniature lead screw pairs addresses the challenges of detecting clearance at the micrometer level due to their small size. It employs a vertically arranged structure, relying on the lead screw's own weight to achieve the lower limit position, and using a combination of a lead screw clamping mechanism and a loading mechanism to achieve the upper limit position. Finally, a displacement measuring mechanism directly acquires the displacement of the upper end of the lead screw at both limit positions, enabling precise measurement of micrometer-level axial clearance. This avoids errors caused by indirect measurements. The overall structure is simple, reducing deformation and thermal errors caused by redundant structures, effectively improving both detection accuracy and efficiency. Attached Figure Description

[0018] Fig. 1 This is a first-view structural schematic diagram of the miniature lead screw pair axial clearance detection device provided in an embodiment of the present invention; Fig. 2 This is a second-view structural schematic diagram of the miniature lead screw pair axial clearance detection device provided in an embodiment of the present invention; Fig. 3 This is a schematic diagram of the use of the miniature lead screw pair axial clearance detection device provided in an embodiment of the present invention.

[0019] In the attached image: 1. Support frame; 2. Positioning seat; 3. Positioning groove; 4. Locking component; 5. First linear guide rail; 6. First slide; 7. Displacement measuring component; 8. First lifting drive component; 9. First limiting component; 10. Second linear guide rail; 11. Lifting seat; 12. Clamping component; 13. Rotation drive component; 14. Floating joint; 15. Tension / compression sensor; 16. First guide wheel; 17. Second guide wheel; 18. Third linear guide rail; 19. Counterweight frame; 20. Chain; 21. Counterweight block; 22. Second slide; 23. Loading drive component; 24. Second lifting drive component; 25. Second limiting component. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "on the upper side," and "over" the second feature include the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature include the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] To address the challenges of high precision requirements and significant testing difficulty in detecting micron-level axial clearance of micro-screw pairs, as well as the tendency of conventional testing devices to introduce additional errors due to structural redundancy, ultimately affecting the reliability of test results, this invention proposes a micro-screw pair axial clearance detection device and its corresponding detection method. This device enables precise measurement of micron-level axial clearance in micro-screw pairs, thereby effectively improving the accuracy and stability of the test data. The technical solution of this invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0024] The axial clearance of the miniature screw pair, which consists of a lead screw and a lead screw nut with threaded engagement, refers to the total clearance between the steel balls in the groove between the lead screw and the lead screw nut and the grooves on both sides. In other words, it is the maximum distance that the lead screw can move axially when the lead screw and lead screw nut are engaged. This axial clearance directly affects the transmission accuracy and positioning accuracy of the miniature screw pair and is a core indicator that must be tested during the production process.

[0025] like Figs. 1 to 3 As shown, the miniature lead screw pair axial backlash detection device of this embodiment includes a support frame 1 and a lead screw fixing mechanism, a lead screw clamping mechanism, a loading mechanism, and a displacement measuring mechanism disposed on the support frame 1, wherein: The lead screw fixing mechanism includes a positioning seat 2 and an adapter fixture. The adapter fixture is used to fix the lead screw and allow the lead screw to rotate freely relative to the lead screw. The positioning seat 2 is used to fix the adapter fixture and keep the axis of the lead screw in the vertical direction. The lead screw clamping mechanism is used to clamp the lower end of the lead screw; The loading mechanism is used to apply a set vertical upward axial force to the clamped lead screw, so that the lead screw produces relative displacement with respect to the fixed lead nut. The displacement measuring mechanism is used to measure the displacement of the upper end of the lead screw, which is the axial clearance value of the miniature lead screw pair.

[0026] Therefore, by adopting a vertically arranged structural layout, the lower limit position is achieved by relying on the weight of the lead screw itself, and the upper limit position is achieved by the cooperation of the lead screw clamping mechanism and the loading mechanism. Then, the displacement of the upper end of the lead screw at the two limit positions is directly obtained by the displacement measuring mechanism, which can accurately measure the axial clearance value at the micron level, avoiding the error caused by indirect measurement. The overall structural layout is simple, reducing deformation and thermal errors caused by redundant structures, and effectively improving the detection accuracy and detection efficiency.

[0027] Optionally, the positioning seat 2 is provided with a positioning groove 3 that matches the shape of the fitting tooling, and locking members 4 are provided on the positioning seat 2 and on both sides of the positioning groove 3. The locking members 4 are used to lock and fix the fitting tooling inserted into the positioning groove 3 onto the positioning seat 2.

[0028] In practical applications, the corresponding adapter tooling can be flexibly changed according to the nut size of different specifications of miniature lead screw pairs. After the adapter tooling is inserted into the positioning groove 3, it is quickly locked by the locking parts 4 on both sides, thus completing the positioning and clamping. The whole process is convenient to operate, and the positioning accuracy is stable and reliable, ensuring that the nut is firmly fixed during the testing process. In this embodiment, the locking part 4 is a lever-type clamping cylinder. This cylinder has a rapid action response and a stable clamping force output, which can quickly complete the clamping and releasing of the adapter tooling. When adapting to the testing needs of various specifications of miniature lead screw pairs, there is no need to repeatedly adjust the clamping accuracy, effectively improving the work efficiency. The design of fixing the adapter tooling and the nut has the advantage that when fixing the adapter tooling later, the requirement for the fit accuracy between the positioning seat 2 and the nut can be reduced, and the clamping damage to the nut body can also be avoided. The specific structure of the adapter tooling and the miniature lead screw pair is not the focus of protection of this invention, and for product confidentiality considerations, it will not be elaborated here.

[0029] Optionally, the support frame 1 is provided with a first linear guide rail 5 extending vertically above the positioning seat 2. The displacement measuring mechanism includes a first slide 6 and a displacement measuring element 7. The first slide 6 is slidably disposed on the first linear guide rail 5. The displacement measuring element 7 is mounted on the first slide 6 and abuts against the upper end of the lead screw. The support frame 1 is provided with a first lifting drive element 8 for driving the first slide 6 to move along the first linear guide rail 5.

[0030] The first lifting drive component 8 can drive the first slide block 6 to move the displacement measuring component 7 up and down, thereby adapting to miniature lead screw pairs of different specifications or lead screws with different extension amounts, so that the displacement measuring component 7 can stably abut against the upper end of the lead screw, making it more adaptable. In this embodiment, the first lifting drive component 8 adopts a motor lead screw module, which has stable driving accuracy and can ensure that the displacement measuring component 7 remains in a fixed position after being adjusted, without imposing additional restrictions or forces on the axial displacement of the lead screw, thus avoiding affecting the measurement results. To meet the measurement accuracy requirements of micron-level axial clearance, the displacement measuring component 7 adopts a high-precision contact displacement sensor with a resolution of 0.1μm.

[0031] Furthermore, the support frame 1 is provided with a first limiting member 9 for limiting the movement range of the first slide block 6 on the first linear guide rail 5. In this embodiment, the first limiting member 9 is a slotted photoelectric sensor arranged at the movement limit position of the first slide block 6. The first slide block 6 is provided with a stroke plate. When the stroke plate moves with the first slide block 6 and triggers the corresponding slotted photoelectric sensor, the first lifting drive member 8 stops driving, avoiding structural collision caused by the first slide block 6 moving beyond its travel range, and improving the operational safety of the device.

[0032] Optionally, the front of the support frame 1 is provided with a second linear guide rail 10 extending vertically below the positioning seat 2. The screw clamping mechanism includes a lifting seat 11 and a clamping member 12. The lifting seat 11 is slidably disposed on the second linear guide rail 10. The clamping member 12 is installed on the side of the lifting seat 11 facing the positioning seat 2. A rotary drive member 13 and a floating joint 14 are provided on the side of the lifting seat 11 facing away from the positioning seat 2. The rotary drive member 13 is used to drive the clamping member 12 to rotate. A tension and pressure sensor 15 is provided at the output end of the loading mechanism. The tension and pressure sensor 15 is connected to the floating joint 14.

[0033] The rotary drive 13 drives the clamping member 12 to rotate, which in turn causes the lead screw to rotate relative to the fixed lead nut, enabling axial clearance measurement at different relative positions. After determining the relative position of the lead screw and the lead nut, the sliding design of the lifting seat 11 can compensate for the axial movement of the lead screw when the loading mechanism applies force. The floating joint 14 can compensate for the coaxiality error between the axial direction of the lead screw and the output end of the loading mechanism, avoiding the impact of eccentric force on the accuracy of the loading force and displacement measurement results. The tension and compression sensor 15 can provide real-time feedback on the loading force to achieve the set axial force and avoid measurement errors caused by insufficient or excessive loading force. In this embodiment, the clamping member 12 adopts a pneumatic chuck, which can stably center and clamp even small-sized lead screws with uniform clamping force without damaging the lead screw. The rotary drive 13 adopts a servo motor, which can precisely control the rotation angle of the lead screw to accurately adjust the relative position of the lead screw and the lead nut.

[0034] To counteract the influence of the weight of the lead screw and lead screw clamping mechanism on the loading force and ensure the accuracy of the applied axial force, a first guide wheel 16 is provided on the front of the support frame 1 and located between the positioning seat 2 and the lifting seat 11. A second guide wheel 17 corresponding to the first guide wheel 16 and a vertically arranged third linear guide rail 18 are provided on the back of the support frame 1. A counterweight frame 19 is slidably mounted on the third linear guide rail 18. A chain 20 passing through the support frame 1 is wound around the first guide wheel 16 and the second guide wheel 17. One end of the chain 20 is connected to the positioning seat 2, and the other end of the chain 20 is connected to the counterweight frame 19. A counterweight block 21 is provided on the counterweight frame 19 to counteract the weight of the lead screw and lead screw clamping mechanism.

[0035] By adjusting the number of counterweights 21, lead screws and lead screw clamping mechanisms of different weights can be flexibly adapted, effectively counteracting the influence of their own weight. After the weight is balanced, the value measured by the tension / compression sensor 15 is the actual axial force applied to the lead screw, eliminating the need for additional error correction or calculation. This design significantly improves the control accuracy of the loading force, avoids interference from self-weight affecting the final axial clearance measurement results, and effectively ensures the accuracy and reliability of the measurement.

[0036] Optionally, the loading mechanism includes a second slide 22 and a loading drive 23. The second slide 22 is slidably disposed on the second linear guide rail 10. The loading drive 23 is mounted on the second slide 22 and connected to the tension and compression sensor 15. The support frame 1 is provided with a second lifting drive 24 for driving the second slide 22 to move along the second linear guide rail 10.

[0037] The second lifting drive component 24 moves the second slide block 22, allowing for rapid adjustment of the initial position of the loading mechanism. This adapts to the detection requirements of lead screws of different lengths, resulting in greater adaptability. In this embodiment, the loading drive component 23 uses a telescopic cylinder, which stably controls the output axial force through air pressure. The control method is simple and the force is stable, providing a stable axial force of the set magnitude and avoiding fluctuations in loading force from affecting the measurement results. The second lifting drive component 24 uses a motor lead screw module similar to the first lifting drive component 8, ensuring stable driving accuracy and quickly adjusting the second slide block 22 to a suitable initial position, guaranteeing stable subsequent loading actions.

[0038] Furthermore, the support frame 1 is provided with a second limiting member 25 for limiting the movement range of the lifting seat 11 on the second linear guide rail 10. In this embodiment, the second limiting member 25 adopts a slot-shaped photoelectric sensor similar to the first limiting member 9, and the lifting seat 11 is provided with a stroke plate, thereby monitoring the axial position of the lead screw, preventing structural collisions or component interference caused by excessive movement, and further improving the safety and operational reliability of the overall structure.

[0039] Based on the aforementioned miniature lead screw axial clearance detection device, the miniature lead screw axial clearance detection method of this embodiment includes the following steps: S1, fix the nut of the miniature lead screw pair to be tested on the adapter fixture, and then fix the adapter fixture on the positioning seat 2 of the lead screw fixing mechanism so that the axis of the lead screw is in the vertical direction and the lead screw of the miniature lead screw pair can rotate freely relative to the lead screw. S2, adjust the relative position of the lead screw and the lead nut. At this time, the lead screw is in the lower limit position of the allowable movement due to the axial clearance between the lead screw and the lead nut under its own weight. Then control the lead screw clamping mechanism to clamp the lower end of the lead screw, and control the displacement measuring component 7 of the displacement measuring mechanism to abut the upper end of the lead screw and complete the zeroing. S3 controls the loading mechanism to apply a set vertical upward axial force to the lead screw, so that the lead screw is in the upper limit position where it can move due to axial clearance. The displacement of the upper end of the lead screw is measured by the displacement measuring mechanism. The displacement is the axial clearance value of the miniature lead screw pair in the relative position.

[0040] Specifically, in step S1, a matching adapter is selected according to the specifications of the miniature lead screw pair. After the adapter is installed into the positioning groove 3 of the positioning seat 2, the adapter is quickly locked and fixed on the positioning seat 2 by the action of the lever-type clamping cylinders on both sides of the positioning groove 3. After the clamping and positioning are completed, the subsequent testing operation can be carried out. If it is necessary to test miniature lead screw pairs of different specifications, simply replace the adapter with the corresponding size and repeat the above clamping steps. There is no need to readjust the entire device, and the clamping efficiency and clamping positioning accuracy can be guaranteed.

[0041] In step S2, the loading mechanism and the lead screw clamping mechanism are first moved along the second linear guide rail 10 by the second lifting drive 24 to adjust to the initial position that matches the current lead screw length. Then, the lead screw is clamped by the clamping member 12, and the rotation drive 13 drives the clamping member 12 to rotate, thereby causing the lead screw to rotate relative to the fixed lead screw nut, adjusting the lead screw to the relative position of the axial clearance to be detected. At this time, the lead screw is not subjected to an upward external force and falls naturally under its own gravity to the lower limit position within the allowable range of axial clearance. Then, the first lifting drive 8 is controlled to move the first slide 6 down along the first linear guide rail 5, so that the probe of the high-precision contact displacement sensor is stably abutted against the upper end face of the lead screw, completing the initial zeroing of the displacement measuring member 7 and eliminating the influence of the initial position error on the measurement result.

[0042] It should be noted that in step S2, only the lower end of the lead screw is clamped by the lead screw clamping mechanism, without applying any additional upward force. The downward tendency generated by the lead screw's own gravity will not change the positioning state of the lead screw at the lower limit position, ensuring the accuracy of the initial position positioning. Furthermore, if it is necessary to measure the axial clearance at multiple different relative positions of the lead screw and nut, after completing the detection at the current position, the rotary drive 13 can rotate the lead screw by a set angle, and the subsequent detection steps can be repeated. This operation is flexible and ensures the accuracy of full-circumferential clearance detection.

[0043] In step S3, the telescopic cylinder of the loading mechanism outputs a set axial force vertically upward. The set axial force is transmitted to the lifting seat 11 through the tension / compression sensor 15 and the floating joint 14, thereby driving the clamped lead screw to move upward as a whole. The tension / compression sensor 15 provides real-time feedback on the current thrust value. When the thrust reaches the preset set axial force, the telescopic cylinder maintains the current output force. At this time, the lead screw is stably stopped at the upper limit position within the allowable range of axial clearance. The high-precision contact displacement sensor collects the displacement change at the upper end of the lead screw in real time. The stable displacement value collected at this time is the axial clearance value of the miniature lead screw pair at the current relative position.

[0044] To meet the testing requirements of different miniature lead screw pairs, the axial force can be flexibly adjusted. The setting can be completed simply by adjusting the output air pressure of the telescopic cylinder. The operation is simple and the force output is stable, avoiding clearance measurement errors caused by the loading force not meeting the testing standards.

[0045] In summary, the axial clearance detection device and method for this miniature lead screw pair have the following advantages: 1) The structure is simple and vertically arranged. It relies on the weight of the lead screw to achieve the lower limit positioning, which reduces the deformation and thermal errors introduced by the redundant structure. It has high detection accuracy and can meet the detection requirements of micron-level axial clearance. 2) Strong clamping adaptability: It can quickly complete the clamping and positioning of miniature lead screw pairs of different specifications by changing the adaptable tooling, without the need for repeated adjustment of the device. The clamping efficiency and positioning accuracy are stable. It can also support the measurement of axial clearance under multiple different relative positions, adapting to diverse testing needs. 3) High loading accuracy: The counterweight offsets the influence of the weight of the lead screw and clamping mechanism, and the tension and compression sensor 15 provides real-time feedback of the force value, which can accurately output the set axial force, avoid the influence of loading force deviation on the measurement results, and further ensure the accuracy of the measurement. 4) High testing efficiency, simple operation process, short testing time per test, adaptable to the full inspection requirements in the batch production process of miniature lead screw pairs, effectively solving the problems of insufficient accuracy and low efficiency of existing conventional testing methods.

[0046] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A device for detecting axial clearance of a miniature lead screw pair, wherein the miniature lead screw pair includes a threaded lead screw and a nut, characterized in that, The miniature lead screw axial clearance detection device includes a support frame (1) and a lead screw fixing mechanism, a lead screw clamping mechanism, a loading mechanism, and a displacement measuring mechanism disposed on the support frame (1), wherein: The lead screw fixing mechanism includes a positioning seat (2) and an adapter fixture. The adapter fixture is used to fix the lead screw and allow the lead screw to rotate freely relative to the lead screw. The positioning seat (2) is used to fix the adapter fixture and keep the axis of the lead screw in the vertical direction. The lead screw clamping mechanism is used to clamp the lower end of the lead screw; The loading mechanism is used to apply a set vertically upward axial force to the clamped lead screw, so that the lead screw is displaced relative to the fixed lead nut. The displacement measuring mechanism is used to measure the displacement of the upper end of the lead screw, and the displacement is the axial clearance value of the miniature lead screw pair.

2. The miniature lead screw pair axial clearance detection device according to claim 1, characterized in that, The positioning seat (2) is provided with a positioning groove (3) that matches the shape of the adapting tooling. Locking members (4) are provided on the positioning seat (2) and on both sides of the positioning groove (3). The locking members (4) are used to lock and fix the adapting tooling placed in the positioning groove (3) on the positioning seat (2).

3. The miniature lead screw pair axial clearance detection device according to claim 1, characterized in that, The support frame (1) is provided with a first linear guide rail (5) extending vertically above the positioning seat (2). The displacement measuring mechanism includes a first slide (6) and a displacement measuring component (7). The first slide (6) is slidably disposed on the first linear guide rail (5). The displacement measuring component (7) is mounted on the first slide (6) and abuts against the upper end of the lead screw. The support frame (1) is provided with a first lifting drive component (8) for driving the first slide (6) to move along the first linear guide rail (5).

4. The miniature lead screw pair axial clearance detection device according to claim 3, characterized in that, The displacement measuring device (7) adopts a high-precision contact displacement sensor with a resolution of 0.1μm.

5. The miniature lead screw pair axial clearance detection device according to claim 3, characterized in that, The support frame (1) is provided with a first limiting member (9) for limiting the movement range of the first slide (6) on the first linear guide rail (5).

6. The miniature lead screw pair axial clearance detection device according to claim 1, characterized in that, The front of the support frame (1) is provided with a second linear guide rail (10) extending vertically below the positioning seat (2). The screw clamping mechanism includes a lifting seat (11) and a clamping member (12). The lifting seat (11) is slidably disposed on the second linear guide rail (10). The clamping member (12) is installed on the side of the lifting seat (11) facing the positioning seat (2). A rotary drive member (13) and a floating joint (14) are provided on the side of the lifting seat (11) facing away from the positioning seat (2). The rotary drive member (13) is used to drive the clamping member (12) to rotate. A tension and pressure sensor (15) is provided at the output end of the loading mechanism. The tension and pressure sensor (15) is connected to the floating joint (14).

7. The miniature lead screw pair axial clearance detection device according to claim 6, characterized in that, A first guide wheel (16) is provided on the front of the support frame (1) and between the positioning seat (2) and the lifting seat (11). A second guide wheel (17) corresponding to the first guide wheel (16) and a vertically arranged third linear guide rail (18) are provided on the back of the support frame (1). A counterweight frame (19) is slidably arranged on the third linear guide rail (18). A chain (20) passing through the support frame (1) is wound around the first guide wheel (16) and the second guide wheel (17). One end of the chain (20) is connected to the positioning seat (2), and the other end of the chain (20) is connected to the counterweight frame (19). A counterweight block (21) is provided on the counterweight frame (19) to counteract the weight of the lead screw and the lead screw clamping mechanism.

8. The miniature lead screw pair axial clearance detection device according to claim 6, characterized in that, The loading mechanism includes a second slide (22) and a loading drive (23). The second slide (22) is slidably disposed on the second linear guide (10). The loading drive (23) is mounted on the second slide (22) and connected to the tension and compression sensor (15). The support frame (1) is provided with a second lifting drive (24) for driving the second slide (22) to move along the second linear guide (10).

9. The miniature lead screw pair axial clearance detection device according to claim 6, characterized in that, The support frame (1) is provided with a second limiting member (25) for limiting the movement range of the lifting seat (11) on the second linear guide rail (10).

10. A method for detecting axial clearance of a miniature lead screw pair, based on the axial clearance detection device for a miniature lead screw pair according to any one of claims 1-9, characterized in that, The method for detecting axial backlash of the miniature lead screw pair includes the following steps: S1, fix the nut of the micro screw pair to be tested on the adapter fixture, and then fix the adapter fixture on the positioning seat (2) of the nut fixing mechanism so that the axis of the nut is in the vertical direction and the screw of the micro screw pair can rotate freely relative to the nut. S2, adjust the relative position of the lead screw and the lead nut. At this time, the lead screw is in the lower limit position allowed to move due to the axial clearance between the lead screw and the lead nut under its own weight. Then control the lead screw clamping mechanism to clamp the lower end of the lead screw, and control the displacement measuring component (7) of the displacement measuring mechanism to abut against the upper end of the lead screw and complete the zeroing. S3, control the loading mechanism to apply a set vertical upward axial force to the lead screw, so that the lead screw is in the upper limit position allowed by the axial clearance. The displacement of the upper end of the lead screw is measured by the displacement measuring mechanism. The displacement is the axial clearance value of the miniature lead screw pair in the relative position.

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