Lead measuring device of ball screw and measuring method thereof

Abstract

The invention discloses a lead measuring device of a ball screw and a measuring method thereof, and the measuring device comprises a rack, the tail end of which is provided with a laser measuring assembly; the lead screw mounting assembly is arranged on the rack and is used for mounting a lead screw to be tested; the linear driving mechanism is mounted on the rack; the measuring platform is installed on the linear driving mechanism, and the linear driving mechanism can drive the measuring platform to reciprocate in the z direction. The measuring platform comprises a measuring sub-group and a reflecting mirror group, the measuring sub-group is in contact with a channel of the lead screw to be measured, and the reflecting mirror group is used for reflecting a laser beam emitted by the laser measuring assembly; by converting the time difference from emission to reception of the laser beam into the length of the moving path, the variation of the lead of the lead screw can be obtained. The linear driving mechanism is adopted to directly drive the measuring platform to move, so that the moving precision and stability can be improved; and by adopting the linkage of the double determinators and the reflector group, the measurement error caused by the bending of the lead screw can be reduced, and the lead measurement precision can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of measurement and testing, and in particular to a lead measuring device and a measuring method for a ball screw. Background Art

[0002] Ball screws are the most commonly used transmission elements in tool machinery and precision machinery. Their main function is to convert rotational motion into linear motion, or torque into axial repetitive force, while having the characteristics of high precision, reversibility and high efficiency. Due to their low friction resistance, ball screws are widely used in various industrial equipment and precision instruments. An important criterion for evaluating the accuracy of ball screws is the lead accuracy of the screw shaft.

[0003] At present, the commonly used lead measurement method in the industry is to use a laser interferometer and a servo motor. A driving stator and a measuring stator are provided on the mobile platform. The servo motor drives the lead screw to rotate. When the lead screw rotates, the driving stator can drive the mobile platform to move axially. The measuring stator is used for measurement. A reflector is provided on the mobile platform to reflect the laser emitted by the laser interferometer. The change in the distance between the mobile platform and the laser interferometer will affect the time difference from laser emission to reception, so that the change in the lead can be calculated.

[0004] The existing measurement methods have the following main disadvantages:

[0005] (1) The axial movement of the mobile platform depends on the full contact between the drive stator and the screw channel, and relies on friction to achieve movement. In this driving mode, if there are foreign particles in the screw channel, or the drive stator and the screw channel are not completely and tightly fitted, and there is a gap, the movement of the mobile platform will be affected (such as jitter, jamming, etc.), which will lead to a decrease in measurement accuracy.

[0006] (2) The movement of the mobile platform is achieved by the friction between the driving stator and the groove. After long-term use, the driving stator will wear out greatly, which will lead to increased measurement errors.

[0007] (3) When the lead screw is bent in the z direction, the lead measurement error is large when the lead screw is bent in the z direction. Summary of the invention

[0008] In view of the shortcomings of the prior art, the present invention provides a lead measuring device and a measuring method for a ball screw. A linear drive mechanism is used to directly drive the measurement platform to move, which can reduce the influence of the screw channel factors on the movement, and is beneficial to improving the accuracy and stability of the movement. The linkage of a double stator and a reflector group is used to reduce the measurement error caused by the bending of the screw, which is beneficial to improving the lead measurement accuracy.

[0009] The technical solution adopted by the present invention to solve the technical problem is: a lead measuring device for a ball screw, comprising:

[0010] a frame having a laser measurement assembly at the rear end thereof;

[0011] A lead screw mounting assembly, which is arranged on the frame and is used to mount the lead screw to be tested;

[0012] A linear drive mechanism, which is mounted on the frame;

[0013] A measuring platform, which is mounted on the linear drive mechanism, and the linear drive mechanism can drive the measuring platform to reciprocate along the z direction;

[0014] The measuring platform includes: a measuring subgroup and a reflector group, the measuring subgroup is in contact with the channel of the lead screw to be measured, and the reflector group is used to reflect the laser beam emitted by the laser measuring component; by converting the time difference from the emission to the reception of the laser beam into the length of the moving path, the change in the lead of the lead screw can be obtained.

[0015] In one example, the measuring subgroup includes: a first measuring subgroup and a second measuring subgroup, wherein the first measuring subgroup and the second measuring subgroup are respectively located on two sides of the lead screw to be measured, and the first measuring subgroup and the second measuring subgroup are located on the same horizontal line in the x direction.

[0016] In one example, the first measuring element and the second measuring element are both in point contact with the channel of the lead screw to be measured.

[0017] In one example, the reflector group includes: a first reflector, a second reflector and a third reflector, the first reflector and the second reflector are respectively located on both sides of the lead screw to be measured, the third reflector is located between the first reflector and the second reflector, and the orthographic projection of the center point of the third reflector in the zox plane falls within the orthographic projection of the axis of the lead screw to be measured in the zox plane.

[0018] In one example, the laser measurement assembly includes: a laser transmitter, a single-beam interferometer, a first reflector, a second reflector and a laser receiver, the laser transmitter, the single-beam interferometer and the first reflector are in a straight line in the z direction, the first reflector and the second reflector are in a straight line in the z direction, the single-beam interferometer and the second reflector are in a straight line in the x direction, and the second reflector and the laser receiver are in a straight line in the z direction.

[0019] In one example, the measuring platform further includes: an air-floating table, the air-floating table is mounted on the linear drive mechanism, the measuring subgroup and the reflector group are both mounted on the air-floating table, and the air-floating table can move freely in the z direction and the x direction.

[0020] In one example, the measuring platform further includes: an inclined mounting seat, the inclined mounting seat is mounted on the air-floating platform, the reflector group is arranged on the inclined mounting seat, and the inclined surface of the inclined mounting seat faces the rear end of the frame.

[0021] The present invention also provides a method for measuring the lead measurement device of a ball screw, comprising the following steps:

[0022] S1. Install the lead screw to be tested on the lead screw mounting assembly, adjust the axis of the lead screw to be tested to be parallel to the z direction, and adjust the position of the measuring subgroup to make it close to the groove of the lead screw to be tested;

[0023] S2, record the initial position of the measuring platform;

[0024] S3, start measuring, the lead screw installation assembly drives the lead screw to be measured to rotate, and at the same time, the linear drive mechanism drives the measuring platform to move along the z direction;

[0025] S4, in the process from the measurement platform starting to move to the process from the measurement platform stopping to the measurement platform starting to move, the laser beam emitted by the laser measurement component is reflected by the reflector group and then received;

[0026] S5. Record the time difference from the emission to the reception of the laser beam, convert the time difference into the moving path length, and convert it into a lead curve after multiple measurements.

[0027] In one example, the laser beam emitted by the laser transmitter passes through the single-beam interferometer and is reflected by the first reflector, the third reflector, and the second reflector in sequence to the first reflector; it is then reflected by the second reflector, the third reflector, and the first reflector in sequence to the single-beam interferometer. The laser beam is refracted 90° by the single-beam interferometer and then reflected by the second reflector to the laser receiver.

[0028] In one example, when the lead screw to be measured bends, the contact points between the first measuring element 411 and the second measuring element 412 and the lead screw will shift. At this time, the reflector group is also shifted by the air floating table. The change in the optical path generated by the first reflector side and the change in the optical path generated by the second reflector side can compensate each other to reduce the final measurement error.

[0029] The beneficial effects of the present invention are:

[0030] (1) The linear drive mechanism is used to drive the measuring head to move along the z-axis, which has higher movement accuracy and is not easily affected by the screw channel factors. It is beneficial to improve the stability and accuracy of the measuring head's movement in the z-axis direction, thereby improving the lead measurement accuracy.

[0031] (2) The measurement method of using double-sided double-sensing elements combined with a reflector group can reduce the measurement error caused by the bending of the lead screw and further improve the lead measurement accuracy.

[0032] (3) The use of an air-floating table allows the measuring device to have space to float in the zx direction during the measurement process, making it less likely to get stuck, which is beneficial to improving the reliability of the measurement.

[0033] (4) An inclined mounting base is used to facilitate the reflector group to reflect the laser emitted by the laser measurement component.

[0034] (5) By improving the structure of the laser measurement component and designing the optical path, the error caused by changes in the optical path can be reduced, which is beneficial to improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0036] Figure 1 It is a three-dimensional structural schematic diagram of the lead measuring device of the present invention.

[0037] Figure 2 It is a side view of the lead measuring device of the present invention.

[0038] Figure 3 It is a schematic structural diagram of the reflector assembly of the present invention.

[0039] Figure 4 Schematic diagram of the structure of the assay subgroup of the present invention.

[0040] Figure 5 It is a schematic diagram of the structure of the first / second measuring element of the present invention.

[0041] Figure 6 It is a structural schematic diagram of the measurement platform of the present invention.

[0042] Figure 7 It is a structural schematic diagram of the laser measurement component of the present invention.

[0043] Figure 8 It is a schematic diagram of the contact point deviation when the lead screw of the present invention is in a bent state.

[0044] In the figure: 1. frame; 2. screw mounting assembly; 3. linear drive mechanism; 4. measuring platform; 5. laser measuring assembly; 6. follow-up center frame; 7. position adjustment platform; 21. DD motor; 22. head top; 23. tail top; 41. measuring subgroup; 42. reflector group; 43. air floating table; 44. tilt mounting seat; 411. first measuring subgroup; 412. second measuring subgroup; 413. connecting part; 414. measuring part; 421. first reflector; 422. second reflector; 423. third reflector; 424. first bracket; 425. second bracket; 51. laser transmitter; 52. single beam interferometer; 53. first reflector; 54. second reflector; 55. laser receiver. DETAILED DESCRIPTION

[0045] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0046] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0047] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Embodiment 1

[0049] like Figure 1As shown, the lead measuring device of the ball screw of this embodiment comprises: a frame 1, a screw mounting assembly 2, a linear drive mechanism 3, a measuring platform 4 and a laser measuring assembly 5. The laser measuring assembly 5 is mounted at the rear end of the frame 1. The screw mounting assembly 2 and the linear drive mechanism 3 are both arranged on the frame 1. The screw mounting assembly 2 is used to mount the screw to be measured. The measuring platform 4 is mounted on the linear drive mechanism 3. The linear drive mechanism 3 can drive the measuring platform 4 to reciprocate along the z direction. The measuring platform 4 comprises: a measuring subgroup 41 and a reflector group 42. The measuring subgroup 41 contacts the channel of the screw to be measured. The reflector group 42 is used to reflect the laser beam emitted by the laser measuring assembly 5. By converting the time difference from the emission to the reception of the laser beam into the moving path length, the variation of the lead of the screw can be obtained.

[0050] This embodiment uses the linear drive mechanism 3 to directly drive the measurement platform to move, which can reduce the influence of the screw channel factor on the movement, and is beneficial to improving the accuracy and stability of the movement of the measurement group.

[0051] In this embodiment, if Figure 4 As shown, the measuring subgroup 41 includes: a first measuring subgroup 411 and a second measuring subgroup 412, the first measuring subgroup 411 and the second measuring subgroup 412 are respectively located on both sides of the lead screw to be measured, and the first measuring subgroup 411 and the second measuring subgroup 412 are on the same horizontal line in the x direction. It should be noted that the two measuring subgroups of this embodiment are both used for measurement, and are in contact with the left and right sides of the lead screw respectively, that is, the first measuring subgroup 411 and the second measuring subgroup 412 are arranged at 180° along the axis of the lead screw. Compared with a single measuring subgroup on one side, the double measuring subgroups on both sides of this embodiment can better cope with the error caused by the bending of the lead screw.

[0052] In this embodiment, if Figure 5 As shown, the first measuring element 411 and the second measuring element 412 are in point contact with the channel of the lead screw to be measured. The first measuring element 411 and the second measuring element 412 both include a connecting portion 413 and a measuring portion 414, and the connecting portion 413 and the measuring portion 414 are integrally formed, wherein the measuring portion 414 is a sphere, and its diameter is significantly smaller than the width of the lead screw channel, so that point contact is formed with the channel. The diameter of the measuring element in the prior art is matched with the channel width (because the movement is achieved by friction), and it is a surface contact. Compared with the prior art, the measuring element of this embodiment is in point contact with the lead screw channel, and the movement of the measuring element in the channel is not easily affected by factors such as foreign particles, nor is it easy to wear.

[0053] In this embodiment, if Figure 6As shown, the measuring platform 4 also includes: an air-floating table 43, the air-floating table 43 is mounted on the linear drive mechanism 3, the measuring subgroup 41 and the reflector group 42 are both mounted on the air-floating table 43, and the air-floating table 43 can move freely in the z direction and the x direction. The linear drive mechanism 3 is, for example, a linear motor, and a mounting plate is connected to the mover of the linear motor, and the air-floating table 43 is mounted on the mounting plate. 24 air-floating bearings are arranged inside the air-floating table 43. The air-floating table 43 can drive the measuring subgroup 41 and the reflector group 42 to move synchronously in the x direction or the z direction. In this way, on the one hand, it can prevent the measuring subgroup 41 from getting stuck during the movement, which is beneficial to improving the stability of the movement; on the other hand, it can also better cope with the situation where the lead screw is bent.

[0054] In this embodiment, if Figure 3 As shown, the reflector group 42 includes: a first reflector 421, a second reflector 422 and a third reflector 423. The first reflector 421 and the second reflector 422 are respectively located on both sides of the lead screw to be measured, and the third reflector 423 is located between the first reflector 421 and the second reflector 422, and the orthographic projection of the center point of the third reflector 423 in the zox plane falls within the orthographic projection of the axis of the lead screw to be measured in the zox plane. It should be noted that the first reflector 421 and the second reflector 422 are arranged symmetrically along the axis of the lead screw, the third reflector 423 is located between the first reflector 421 and the second reflector 422, the third reflector 423 is located directly below the lead screw to be measured, and the reflective surface of the third reflector 423 faces upward. The advantages of this design of the embodiment are that, first, the laser emitted by the laser measurement assembly 5 is reflected in sequence by the first reflector 421, the third reflector 423, and the second reflector 422, which can prevent the laser from being blocked by the lead screw (i.e., the laser goes around the bottom of the lead screw), and this design can also make the measuring device adaptable to the test of lead screws of different diameters without reconsidering the direction of the light. Second, the layout of the reflector group 42 allows the measuring axis of the reflector group 42 to remain parallel to the axis of the lead screw in the vertical direction, thereby reducing the measurement error caused by the geometric position, which is conducive to improving the lead measurement accuracy.

[0055] In this embodiment, the measuring platform 4 further includes: an inclined mounting seat 44, the inclined mounting seat 44 is mounted on the air-floating platform 43, and the reflector group 42 is arranged on the inclined mounting seat 44, and the inclined surface of the inclined mounting seat 44 faces the rear end of the frame 1. It should be noted that the first reflector 421 is mounted on the upper left corner of the inclined mounting seat 44 through the first bracket 424, the second reflector 422 is mounted on the upper right corner of the inclined mounting seat 44 through the second bracket 425, and the third reflector 423 is directly mounted on the middle part of the inclined mounting seat 44, and the inclined angle of the inclined surface of the inclined mounting seat 44 is, for example, 35°. The reason for the design of this embodiment is that it is convenient for the reflector group 42 to reflect the laser emitted by the laser measuring component 5. If the reflector group 42 is mounted on a horizontal plane, the laser received by the first reflector 421 cannot be reflected to the third reflector 423.

[0056] In this embodiment, if Figure 7 As shown, the laser measurement assembly 5 includes: a laser emitter 51, a single-beam interferometer 52, a first reflector 53, a second reflector 54 and a laser receiver 55. The laser emitter 51, the single-beam interferometer 52 and the first reflector 421 are in a straight line in the z direction, the first reflector 53 and the second reflector 422 are in a straight line in the z direction, the single-beam interferometer 52 and the second reflector 54 are in a straight line in the x direction, and the second reflector 54 and the laser receiver 55 are in a straight line in the z direction. It should be noted that the laser emitted by the laser transmitter 51 passes through the single-beam interferometer 52 and is reflected by the first reflector 421 to the third reflector 423, and then reflected by the third reflector 423 to the second reflector 422. The second reflector 422 reflects the laser to the first reflector 53. The first reflector 53 reflects the laser 180° and returns it to the second reflector 422. The second reflector 422 then reflects the laser to the third reflector 423. The third reflector 423 reflects it to the first reflector 421. The first reflector 421 reflects it to the single-beam interferometer 52, and is refracted 90° to the second reflector 54 through the single-beam interferometer 52, and is reflected 90° by the second reflector 54 to be received by the laser receiver 55.

[0057] In the measurement process of this embodiment, the laser undergoes multiple reflections from emission to reception. Compared with the single reflection of the prior art, the time difference Δt from emission to reception of the laser in this embodiment is significantly increased. The reason for the design of this embodiment is that during measurement, the sampling interval between the emission and reception of the laser by the host computer is fixed, and generally speaking, the sampling interval is relatively short. The speed of laser light is very fast (3*10 8m / s), if there is only one reflection, the time difference Δt is very short, so when the host computer collects data, it is possible to miss some transmission / reception moments, resulting in incomplete data recording and affecting the subsequent calculation accuracy. This embodiment can extend the time difference Δt through structural improvement, ensure that the host computer can record all data in the measurement process, and improve the subsequent calculation accuracy. Furthermore, this embodiment is designed in this way, and it can also reduce the error caused by the change of the optical path, and further improve the measurement accuracy.

[0058] In this embodiment, the lead screw installation assembly 2 includes: a DD motor 21, a head top 22 and a tail top 23. During measurement, the lead screw to be measured is clamped between the head top 22 and the tail top 23, and the lead screw to be measured is driven to rotate by the DD motor 21. The tail top 23 is an elastic top, which is conducive to improving the convenience of disassembly and assembly of the lead screw. A follower center frame 6 is also provided on the mounting plate of the linear motor, which is used to support the lead screw to be measured to prevent the lead screw to be measured from sagging during the measurement process. A position adjustment platform 7 is also provided at the tail end of the frame 1, and the laser measurement component 5 is installed on the position adjustment platform 7. The position adjustment platform 7 can adjust the position of the laser measurement component 5 in the x direction so that the laser measurement component 5 can be aligned with the reflector group 42 during measurement.

[0059] Embodiment 2

[0060] The measurement method of this embodiment includes the following steps: S1. Install the lead screw to be measured on the lead screw mounting assembly 2, adjust the axis of the lead screw to be measured to be parallel to the z direction, and adjust the position of the measuring subgroup 41 to make it close to the channel of the lead screw to be measured. S2. Record the initial position of the measuring platform 4. S3. Start measuring, the lead screw mounting assembly 2 drives the lead screw to be measured to rotate, and at the same time, the linear drive mechanism 3 drives the measuring platform 4 to move along the z direction. S4. In the process from the beginning to the end of the movement of the measuring platform 4, the laser beam emitted by the laser measurement assembly 5 is reflected by the reflector group 42 and then received. S5. Record the time difference from the emission to the reception of the laser beam, and convert the time difference into the path length of the movement, and convert it into a lead curve after multiple measurements.

[0061] It should be noted that the laser light path of this embodiment is as follows: the laser beam emitted by the laser emitter 51 passes through the single-beam interferometer 52 and is reflected by the first reflector 421, the third reflector 423, and the second reflector 422 to the first reflector 53 in sequence; it is then reflected by the second reflector 422, the third reflector 423, and the first reflector 421 to the single-beam interferometer 52 in sequence, and the laser beam is refracted 90° by the single-beam interferometer 52 and is reflected by the second reflector 54 to the laser receiver 55. When the lead screw to be measured is bent, the contact points between the first measuring element 411 and the second measuring element 412 and the lead screw will shift. At this time, the reflector group 42 is also shifted by the air-floating platform 43, and the optical path change amount generated on the first reflector 421 side and the optical path change amount generated on the second reflector 422 side can compensate each other to reduce the final measurement error.

[0062] Compared with the measurement method of the prior art using a single stator and a single reflector, the measurement method of this embodiment can reduce the error caused by the bending of the lead screw, as described in detail below.

[0063] like Figure 8 As shown, when the lead screw is not bent, the contact point between the first measuring element 411 and the lead screw channel is recorded as point b, and the contact point between the second measuring element and the lead screw channel is recorded as point a; when the lead screw is bent, the lead screw axis and the measuring axis are not in the same straight line. Due to the bending of the lead screw, the positions of contact points a and b will be offset, and the offset contact points are a' and b'. Due to the different bending radii on both sides of the lead screw, the offset of the contact point caused by the bending will be slightly different. Assume that the bending radius of the lead screw is R, the diameter of the lead screw is D, the bending length is L, and the lead angle of the lead screw is β.

[0064] The coordinates of the contact point a' in the zx direction with the center of the bending circle as the midpoint are:

[0065]

[0066] The coordinates of the contact points after the rotation of the coordinate system are:

[0067]

[0068] Then the calculation can be obtained:

[0069]

[0070] When the lead screw is not bent, the coordinates of the contact points a and b are:

[0071] Then the deviation of the screw in the x direction after bending is:

[0072] Δx a-a' =x a -x a' , Δxb-b' =x b -x b' ;

[0073] The deviation of the lead screw in the z direction after bending is:

[0074] Δz a-a' =z a -z a' , Δz b-b' =z b -z b' .

[0075] Assuming R = 10m, D = 40mm, L = 1m, β = 7°, then

[0076] The deviation due to bending in the z direction is:

[0077] Δz a-a' =z a -z a' =1mm, Δz b-b' =z b -z b' =1.0062mm.

[0078] The prior art adopts a single-sided single measuring element and a single reflector measurement method (i.e., only contact point a or b), and the measurement error generated when the lead screw is bent is 1mm or 1.0062mm. However, the present embodiment adopts a double-sided double measuring element combined with a reflector group 42. When the lead screw is bent, the positions of the two measuring elements are offset, and the reflector group 42 can be driven to be offset synchronously through the air-floating platform 43. The first reflector 421 and the second reflector 422 are located on both sides of the lead screw. When the offset occurs, the optical path on the side of the first reflector 421 is shortened, and the optical path on the side of the second reflector 422 is correspondingly increased. The increase and decrease of the optical paths on both sides can compensate each other to a certain extent, that is, the final measurement error generated by the bending of the lead screw in the present embodiment is |1-1.0062|=0.0062mm, which is about 99% lower than that of the prior art, and significantly improves the measurement accuracy of the lead when the lead screw is bent.

[0079] In summary, the lead measuring device and the measuring method of the ball screw of the present invention have the following advantages:

[0080] (1) The linear drive mechanism 3 is used to drive the measuring head to move along the z-axis, which has higher movement accuracy and is not easily affected by screw channel factors (such as impurities, incomplete fitting, etc.), which is beneficial to improving the stability and accuracy of the measuring head's movement in the z-axis direction, thereby improving the lead measurement accuracy.

[0081] (2) Compared with the measurement method using a single stator on one side, the present invention uses a measurement method using double stators on both sides in combination with a reflector assembly 42, which can reduce the measurement error caused by the bending of the lead screw and further improve the lead measurement accuracy.

[0082] (3) The air-floating platform 43 is used so that the measuring element has floating space in the zx direction during the measurement process, and is not prone to getting stuck, which is beneficial to improving the reliability of the measurement.

[0083] (4) The inclined mounting seat 44 is used to facilitate the reflection mirror group 42 to reflect the laser emitted by the laser measurement component 5.

[0084] (5) By improving the structure of the laser measurement component 5 and designing the optical path, the error caused by the change of the optical path can be reduced, which is conducive to improving the measurement accuracy.

[0085] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A lead measuring device for a ball screw, characterized in that: include: A frame (1) having a laser measurement assembly (5) disposed at its rear end; A lead screw mounting assembly (2), which is arranged on the frame (1) and is used for mounting the lead screw to be tested; A linear drive mechanism (3) mounted on the frame (1); A measuring platform (4), which is mounted on the linear drive mechanism (3), and the linear drive mechanism (3) is capable of driving the measuring platform (4) to reciprocate along the z direction; The measuring platform (4) comprises: a measuring subgroup (41) and a reflector group (42), wherein the measuring subgroup (41) contacts the channel of the lead screw to be measured, and the reflector group (42) is used to reflect the laser beam emitted by the laser measuring component (5); by converting the time difference from the emission to the reception of the laser beam into the length of the moving path, the variation of the lead of the lead screw can be obtained.

2. The lead measuring device of a ball screw according to claim 1, characterized in that: The measuring subgroup (41) comprises: a first measuring subgroup (411) and a second measuring subgroup (412), wherein the first measuring subgroup (411) and the second measuring subgroup (412) are respectively located on two sides of the lead screw to be measured, and the first measuring subgroup (411) and the second measuring subgroup (412) are located on the same horizontal line in the x direction.

3. The lead measuring device of a ball screw according to claim 2, characterized in that: The first measuring element (411) and the second measuring element (412) are both in point contact with the channel of the lead screw to be measured.

4. The lead measuring device of a ball screw according to claim 1, characterized in that: The reflector group (42) comprises: a first reflector (421), a second reflector (422) and a third reflector (423), wherein the first reflector (421) and the second reflector (422) are respectively located on two sides of the lead screw to be measured, and the third reflector (423) is located between the first reflector (421) and the second reflector (422), and the orthographic projection of the center point of the third reflector (423) on the zox plane falls within the orthographic projection of the axis of the lead screw to be measured on the zox plane.

5. The lead measuring device of a ball screw according to claim 4, characterized in that: The laser measurement assembly (5) comprises: a laser transmitter (51), a single-beam interferometer (52), a first reflector (53), a second reflector (54) and a laser receiver (55); the laser transmitter (51), the single-beam interferometer (52) and the first reflector (421) are located in a straight line in the z direction; the first reflector (53) and the second reflector (422) are located in a straight line in the z direction; the single-beam interferometer (52) and the second reflector (54) are located in a straight line in the x direction; and the second reflector (54) and the laser receiver (55) are located in a straight line in the z direction.

6. The lead measuring device of a ball screw according to claim 1, characterized in that: The measuring platform (4) further comprises: an air-floating platform (43), wherein the air-floating platform (43) is mounted on the linear drive mechanism (3), the measuring subgroup (41) and the reflector group (42) are both mounted on the air-floating platform (43), and the air-floating platform (43) can move freely in the z direction and the x direction.

7. The lead measuring device of a ball screw according to claim 6, characterized in that: The measuring platform (4) further comprises: an inclined mounting seat (44), the inclined mounting seat (44) being mounted on the air-floating platform (43), the reflector group (42) being arranged on the inclined mounting seat (44), and the inclined surface of the inclined mounting seat (44) facing the rear end of the frame (1).

8. A method for measuring the lead of a ball screw according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Install the lead screw to be tested on the lead screw installation assembly (2), adjust the axis of the lead screw to be tested to be parallel to the z direction, and adjust the position of the measuring subassembly (41) to make it close to the channel of the lead screw to be tested; S2, recording the initial position of the measuring platform (4); S3, start measuring, the lead screw installation assembly (2) drives the lead screw to be measured to rotate, and at the same time, the linear drive mechanism (3) drives the measuring platform (4) to move along the z direction; S4, when the measuring platform (4) starts to move and stops moving, the laser beam emitted by the laser measuring component (5) is reflected by the reflector group (42) and then received; S5. Record the time difference from the emission to the reception of the laser beam, convert the time difference into the moving path length, and convert it into a lead curve after multiple measurements.

9. The measuring method according to claim 8, characterized in that: The laser beam emitted by the laser emitter (51) passes through the single-beam interferometer (52) and is reflected by the first reflector (421), the third reflector (423) and the second reflector (422) in sequence to the first reflector (53); it is then reflected by the second reflector (422), the third reflector (423) and the first reflector (421) in sequence to the single-beam interferometer (52); the laser beam is refracted 90 degrees by the single-beam interferometer (52) and is reflected by the second reflector (54) to the laser receiver (55).

10. The measuring method according to claim 9, characterized in that: When the lead screw to be measured is bent, the contact points between the first measuring element 411 and the second measuring element 412 and the lead screw will shift. At this time, the reflector group (42) is also shifted by the air floating platform (43). The optical path change generated on the side of the first reflector (421) and the optical path change generated on the side of the second reflector (422) can compensate each other to reduce the final measurement error.

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