Lead screw thread measuring instrument with anti-collision structure

Abstract

The utility model discloses a lead screw thread measuring instrument with an anti-collision structure in the technical field of thread detection, which comprises a main shaft module, a confocal laser sensor and a sliding platform, the confocal laser sensor is fixed on a mounting seat of the sliding platform, the head of the confocal laser sensor is covered with a protective cover, the protective cover is in sliding connection with the mounting seat, and the confocal laser sensor is fixed on the sliding platform. The sliding direction is the axis direction of the confocal laser sensor, a microswitch is arranged on the mounting base, an ejector rod capable of touching the microswitch is arranged on the protective cover, proximity switches are arranged on the left side and the right side of the protective cover, and a controller used for controlling the sliding platform to move is electrically connected with the microswitch and the proximity switches. The confocal laser sensor protection cover has the beneficial effects that when the protection cover is in contact with a workpiece to be detected or is close to other parts of equipment in the moving process of the confocal laser sensor, the microswitch and the proximity switch can emergently stop the confocal laser sensor from continuously moving, so that the safety of the confocal laser sensor is ensured, and the service life of the equipment is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of thread detection technology, and in particular to a screw thread measuring instrument with an anti-collision structure. Background Technology

[0002] Planetary roller screws are transmission devices that convert rotary motion into linear motion. They are characterized by their small size, high load capacity, high precision, and long service life, and are widely used in aerospace, precision machine tools, robotics, and medical devices. The demand for planetary roller screws with small leads, high load capacity, and high precision is particularly prominent under confined space and specific operating conditions.

[0003] Currently, the thread measurement of the main screw and roller threads of planetary roller screw pairs is performed using a contact profilometer. While this method is time-consuming due to the small pitch of the screw and rollers, the profilometer may scratch the thread being measured, leading to rapid wear and increased replacement costs. There are also non-contact measurement methods, such as the laser-based thread measurement scheme disclosed in patent document CN113375550A. This scheme primarily uses a spectral confocal laser sensor to quickly acquire the coordinate information of the thread under test. Internally, the data collected by the laser displacement sensor is filtered, and then the least squares method is used to perform curve fitting on the filtered discrete data to obtain the thread profile detection curve. Based on the definition of the thread's geometric parameters, the major diameter, minor diameter, pitch diameter, thread angle, pitch, and pitch error are calculated using a constrained least squares fitting method. Due to the divergence of light, to ensure measurement accuracy, the laser measuring head needs to be as close as possible to the lead screw being measured. At the same time, an automated drive mechanism is needed to control the movement of the laser sensor. Since the laser measuring head is a high-precision device, if the input parameters are incorrect, the laser measuring head may come into contact with the lead screw or other parts of the equipment, thereby damaging the laser sensor. Utility Model Content

[0004] To overcome the above-mentioned shortcomings of existing thread testing devices, the technical problem to be solved by this utility model is to provide a screw thread measuring instrument with an anti-collision structure.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A lead screw thread measuring instrument with an anti-collision structure includes a measuring instrument body for clamping both ends of the lead screw to be measured and driving the lead screw to rotate around its axis, a confocal laser sensor for detecting the thread, and a sliding platform for carrying and driving the confocal laser sensor to move along the X, Y, and Z directions. The confocal laser sensor is fixed on a mounting base, and its head is covered with a protective cover. The protective cover is slidably connected to the mounting base, and a return spring is provided between the two. The sliding direction is the axial direction of the confocal laser sensor. A micro switch is provided on the mounting base, and a push rod that can touch the micro switch is provided on the protective cover. Proximity switches are provided on the left and right sides of the protective cover. A controller for controlling the movement of the sliding platform is electrically connected to the micro switch and the proximity switch, and is configured to stop the movement of the sliding platform when the micro switch or the proximity switch is triggered during the movement of the sliding platform.

[0007] Furthermore, the measuring instrument body includes a frame, a lower spindle fixed at the bottom of the frame, and an upper spindle that can be raised and lowered and mounted on the frame. The ends of the upper and lower spindles are provided with centers. The lead screw to be measured is fixed to the measuring instrument body through the cooperation of the reference holes at both ends with the upper and lower centers. The axial direction of the lead screw to be measured is the Z-axis direction.

[0008] Furthermore, the sliding platform includes a Z-axis electric slide, a Y-axis electric slide, and an X-axis electric slide. The Z-axis electric slide is slidably mounted on the side of the frame in the vertical direction, the Y-axis electric slide is slidably mounted on the Z-axis electric slide in the Y direction, and the X-axis electric slide is slidably mounted on the Y-axis electric slide in the X direction. The mounting base is mounted on the X-axis electric slide, and the laser emission direction of the confocal laser sensor is in the X direction.

[0009] Furthermore, the upper spindle, Z-axis electric slide, Y-axis electric slide, and X-axis electric slide are all raised or moved by linear motors or lead screw and nut transmission mechanisms, and the center on the upper spindle is raised or lowered by a quick return handle.

[0010] Furthermore, the mounting base includes a base plate and a fixing clip disposed on the base plate. The confocal laser sensor is clamped and fixed to the mounting base by the fixing clip, and the mounting base is fixed to the sliding platform by the base plate.

[0011] Furthermore, a protective sleeve is provided on the side of the fixing clamp facing the head of the confocal laser sensor, and the protective cover is slidably mounted on the protective sleeve.

[0012] Furthermore, the front end of the protective sleeve is provided with a guide hole along its axial direction, and a guide rod is slidably disposed in the guide hole. The end of the guide rod away from the protective sleeve is fixed to the inner side of the head of the protective cover. The reset spring passes through the guide rod and abuts against the front end of the protective sleeve and the inner side of the head of the protective cover.

[0013] Furthermore, the guide holes include at least three, which are evenly spaced along the circumference of the protective sleeve, and each guide hole is provided with a guide rod and a return spring.

[0014] Furthermore, one of the guide holes penetrates the protective sleeve and the protective cover, and the guide rod located in the guide hole acts as a push rod, with its end away from the protective cover able to touch the micro switch.

[0015] Furthermore, the protective cover has a limiting through hole on its side, and the protective sleeve has a limiting post that passes through the limiting through hole.

[0016] The beneficial effects of this utility model are as follows: by setting a protective cover on the head of the confocal laser sensor and a proximity switch on the protective cover, and setting a micro switch that can be linked with the protective cover on the mounting bracket of the confocal laser sensor, when the protective cover contacts the lead screw being measured or approaches other parts of the equipment during the movement of the confocal laser sensor, the micro switch and the proximity switch can stop the confocal laser sensor from continuing to move in an emergency, thereby ensuring the safety of the confocal laser sensor and improving the service life of the equipment. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0018] Figure 2 This is a top view of the confocal laser sensor of this utility model;

[0019] Figure 3 This is a side view of the confocal laser sensor of this utility model;

[0020] Figure 4 yes Figure 2 AA section view;

[0021] Figure 5 yes Figure 4 Enlarged view of section B.

[0022] The diagram is labeled as follows: 1- Measuring instrument body, 2- Confocal laser sensor, 3- Z-axis electric slide, 4- Y-axis electric slide, 5- X-axis electric slide, 6- Measured lead screw, 11- Frame, 12- Lower spindle, 13- Upper spindle, 14- Center, 15- Quick return handle, 21- Mounting base, 22- Protective cover, 23- Return spring, 24- Micro switch, 25- Push rod, 26- Proximity switch, 211- Base plate, 212- Fixing clamp, 213- Protective sleeve, 214- Guide hole, 215- Guide rod, 216- Limiting post, 221- Limiting through hole. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] It should be noted that if this utility model contains directional indicators such as up, down, left, right, front, and back, these terms are used to describe the relative positional relationships between components and are not specific references to the absolute positions of the components or the relationships between them. They are only used to explain the relative positional relationships and movement of the components in a specific posture. If the specific posture changes, the directional indicator will also change accordingly. If this utility model contains terms related to quantity such as "many," "multiple," or "several," these terms specifically refer to two or more.

[0025] like Figure 1-3 As shown, the present invention provides a screw thread measuring instrument with an anti-collision structure, comprising a measuring instrument body 1 for clamping both ends of the screw 6 to be measured and driving the screw 6 to be measured to rotate around its axis, a confocal laser sensor 2 for detecting the thread, and a sliding platform for supporting and driving the confocal laser sensor 2 to move along the X, Y and Z directions. The confocal laser sensor 2 is fixed on a mounting base 21, and its head is covered with a protective cover 22. The protective cover 22 is slidably connected to the mounting base 21, and a return spring 23 is provided between the two. The sliding direction is the axial direction of the confocal laser sensor. A micro switch 24 is provided on the mounting base 21, and a top rod 25 that can touch the micro switch 24 is provided on the protective cover 22. Proximity switches 26 are provided on the left and right sides of the protective cover 22. A controller for controlling the movement of the sliding platform is electrically connected to the micro switch 24 and the proximity switch 26, and is configured to stop the movement of the sliding platform when the micro switch 24 or the proximity switch 26 is triggered during the movement of the sliding platform. The head of the protective cover 22 is an open structure that extends beyond the head of the confocal laser sensor 2, which can provide anti-collision protection without affecting the passage of the laser.

[0026] The specific method for measuring threads using the confocal laser sensor 2 is existing technology. This application mainly involves hardware modifications and does not involve algorithms and control software during the measurement process. The micro switch 24 and proximity switch 26 used in this application are both existing mature products, and are linked with the controller that controls the movement of the sliding platform using existing control logic. The working process of this utility model is as follows: Before measurement, in its natural state, the return spring 23 disengages the push rod 25 from the micro switch 24. When the diameter of the workpiece being measured is input by the user incorrectly and is smaller than the actual diameter, the moving distance of the confocal laser sensor 2 in the X direction will increase. During the movement, the protective cover 22 will first contact the workpiece being measured and move backward, compressing the return spring 23. This causes the push rod 25 connected to the protective cover 22 to move backward, compressing the micro switch 24, thereby triggering a system alarm and stopping the measurement program. In addition, before measurement, the confocal laser sensor 2 needs to be aligned with the axis of the workpiece by moving along the Y direction. The moving distance is determined based on the diameter of the workpiece. If an input error occurs, the confocal laser sensor 2 will deviate in its Y-axis movement, potentially touching other parts of the equipment or workpiece. The proximity switch 26 can trigger a system alarm in such cases, stopping the measurement program and ensuring safety during the measurement process. The measurement process mainly involves the confocal laser sensor 2 precisely focusing its light spot onto the thread profile of the lead screw 6 being measured. Then, the confocal laser sensor 2 moves along the Z direction to measure one thread profile section. Afterward, the lead screw 6 is rotated to measure the next section, while the confocal laser sensor 2 moves synchronously along the Z direction until the entire thread measurement of the lead screw 6 is completed.

[0027] The measuring instrument body 1 includes a frame 11, a lower spindle 12 fixed to the bottom of the frame 11, and an upper spindle 13 that can be raised and lowered and mounted on the frame 11. Both the upper spindle 13 and the lower spindle 12 have centers 14 at their rotating ends. The lead screw 6 being measured is fixed to the measuring instrument body 1 through the engagement of reference holes at both ends with the centers 14. The upper spindle 13 and the lower spindle 12 need to be coaxially aligned and rotate synchronously. The raised and lowerable upper spindle 13 can accommodate lead screws of different lengths and can also clamp and fix the lead screw 6 by pushing the centers 14. Fixing the lead screw 6 by engaging the centers 14 with the reference holes at both ends ensures that the axis of the lead screw 6 is vertical, i.e., aligned with the Z-axis.

[0028] For the sliding platform, to achieve XYZ three-axis movement, the solution adopted in this invention is as follows: the sliding platform includes a Z-axis electric slide 3, a Y-axis electric slide 4, and an X-axis electric slide 5. The Z-axis electric slide 3 is slidably mounted vertically on the side of the frame 11; the Y-axis electric slide 4 is slidably mounted on the Z-axis electric slide 3 along the Y-axis; and the X-axis electric slide 5 is slidably mounted on the Y-axis electric slide 4 along the X-axis. The mounting base 21 is mounted on the X-axis electric slide 5, and the laser emission direction of the confocal laser sensor 2 is X-axis. The upper spindle 13, Z-axis electric slide 3, Y-axis electric slide 4, and X-axis electric slide 5 can be raised or lowered or moved via linear motors or lead screw and nut transmission mechanisms. These mechanisms are quite common; existing mature products can be selected according to the required control precision. When inspecting similar lead screws, to quickly replace the lead screw, the center 14 on the upper spindle 13 can be raised or lowered via the quick-return handle 15. After completing the test of one lead screw 6, press down the quick return handle 15 to make the tip 14 retract quickly. Then, after replacing the lead screw 6, release or lift the quick return handle 15 to make the tip 14 extend and fix the lead screw 6.

[0029] Regarding the installation method of the confocal laser sensor 2, such as Figure 2-4 As shown, the mounting base 21 includes a base plate 211 and a fixing clip 212 disposed on the base plate 211. The fixing clip 212 can be a C-shaped housing with an opening connected by bolts. The confocal laser sensor 2 is clamped and fixed to the mounting base 21 by the fixing clip 212, and the mounting base 21 is fixed to the sliding platform by the base plate 211. For the sliding connection between the protective cover 22 and the mounting bracket 21, the preferred embodiment of this utility model is as follows: Figure 4 As shown, a protective sleeve 213 is provided on the side of the fixing clamp 212 facing the head of the confocal laser sensor 2, and the protective cover 22 is slidably disposed on the protective sleeve 213.

[0030] Regarding the arrangement of the return spring 23, the preferred embodiment of this utility model is as follows: Figure 5As shown, the front end of the protective sleeve 213 is provided with guide holes 214 evenly spaced along its circumference. A guide rod 215 is slidably disposed within the guide holes 214. The end of the guide rod 215 away from the protective sleeve 213 is fixed to the inner side of the head of the protective cover 22. The return spring 23 passes through the guide rod 215 and abuts against the front end of the protective sleeve 213 and the inner side of the head of the protective cover 22. To ensure that the force is evenly distributed when the protective cover 22 resets, the guide holes 214 preferably include at least three and are evenly spaced along the circumference of the protective sleeve 213. Each guide hole 214 is provided with a guide rod 215 and a return spring 23. When the protective cover 22 touches the lead screw 6 being tested, the guide rod 215 will move backward with the protective cover 22, compressing the return spring 23 at the same time. When the protective cover 22 disengages from the lead screw 6 being tested, under the elastic force of the return spring 23, the guide rod 215 and the protective cover 22 move forward together, returning to the initial position.

[0031] Furthermore, to simplify the structure, one of the guide holes 214 can pass through the protective sleeve 213 and the protective cover 22, so that the guide rod 215 located in the guide hole 214 can be directly used as the push rod 25, with its end away from the protective cover 22 extended rearward to a position that can touch the micro switch 24. In this way, when the protective cover 22 is touched and moves backward, the guide rod 215 can directly trigger the micro switch 24. Additionally, to prevent the protective cover 22 from detaching from the protective sleeve 213 under elastic force, such as... Figure 3 As shown, a limiting through hole 221 can be provided on the side of the protective cover 22, and a limiting post 216 passing through the limiting through hole 221 is provided on the protective sleeve 213. The limiting through hole 221 can be a larger round hole or a strip hole, and the limiting post 216 can be a screw. By cooperating with the limiting post 216 and the limiting through hole 221, the movement of the protective cover 22 can be restricted within a certain range, thereby preventing the protective cover 22 from detaching from the protective sleeve 213 or from causing the micro switch 24 or other equipment to malfunction due to excessive movement.

Claims

1. A screw thread measuring instrument with an anti-collision structure, comprising a measuring instrument body (1) for clamping both ends of the screw (6) to be measured and capable of driving the screw (6) to be measured to rotate around its axis, a confocal laser sensor (2) for detecting the thread, and a sliding platform for supporting and driving the confocal laser sensor (2) to move along the X, Y and Z directions, characterized in that: The confocal laser sensor (2) is fixed on the mounting base (21), and its head is covered with a protective cover (22). The protective cover (22) is slidably connected to the mounting base (21), and a return spring (23) is provided between them. The sliding direction is the axial direction of the confocal laser sensor (2). The mounting base (21) is provided with a micro switch (24), and the protective cover (22) is provided with a top rod (25) that can touch the micro switch (24). The left and right sides of the protective cover (22) are provided with proximity switches (26). The controller used to control the movement of the sliding platform is electrically connected to the micro switch (24) and the proximity switch (26), and is configured to stop the movement of the sliding platform when the micro switch (24) or the proximity switch (26) is triggered during the movement of the sliding platform.

2. The lead screw thread measuring instrument with anti-collision structure as described in claim 1, characterized in that: The measuring instrument body (1) includes a frame (11), a lower spindle (12) fixed at the bottom of the frame (11), and an upper spindle (13) that can be raised and lowered and is mounted on the frame (11). The upper spindle (13) and the lower spindle (12) are both provided with a center (14) at their rotating ends. The lead screw (6) being measured is fixed on the measuring instrument body (1) through the cooperation of the reference holes at both ends with the two centers (14). The axial direction of the lead screw (6) being measured is the Z-axis direction.

3. The lead screw thread measuring instrument with anti-collision structure as described in claim 2, characterized in that: The sliding platform includes a Z-axis electric slide (3), a Y-axis electric slide (4), and an X-axis electric slide (5). The Z-axis electric slide (3) is slidably mounted on the side of the frame (11) in the vertical direction. The Y-axis electric slide (4) is slidably mounted on the Z-axis electric slide (3) in the Y direction. The X-axis electric slide (5) is slidably mounted on the Y-axis electric slide (4) in the X direction. The mounting base (21) is mounted on the X-axis electric slide (5), and the laser emission direction of the confocal laser sensor (2) is in the X direction.

4. The lead screw thread measuring instrument with anti-collision structure as described in claim 3, characterized in that: The upper spindle (13), Z-axis electric slide (3), Y-axis electric slide (4) and X-axis electric slide (5) are all raised or moved by a linear motor or a lead screw and nut transmission mechanism. The center point (14) on the upper spindle (13) is raised or lowered by a quick return handle (15).

5. The screw thread measuring instrument with anti-collision structure as described in any one of claims 1-4, characterized in that: The mounting base (21) includes a base plate (211) and a fixing clip (212) disposed on the base plate (211). The confocal laser sensor (2) is clamped and fixed on the mounting base (21) by the fixing clip (212). The mounting base (21) is fixed on the sliding platform by the base plate (211).

6. The lead screw thread measuring instrument with anti-collision structure as described in claim 5, characterized in that: The fixing clip (212) is provided with a protective sleeve (213) on the side facing the head of the confocal laser sensor (2), and the protective cover (22) is slidably disposed on the protective sleeve (213).

7. The lead screw thread measuring instrument with anti-collision structure as described in claim 6, characterized in that: The front end of the protective sleeve (213) is provided with guide holes (214) evenly spaced along its circumference. A guide rod (215) is slidably disposed in the guide hole (214). The end of the guide rod (215) away from the protective sleeve (213) is fixed to the inner side of the head of the protective cover (22). The reset spring (23) is connected to the guide rod (215) and abuts between the front end of the protective sleeve (213) and the inner side of the head of the protective cover (22).

8. The lead screw thread measuring instrument with anti-collision structure as described in claim 7, characterized in that: The guide holes (214) include at least three and are evenly spaced along the circumference of the protective sleeve (213). Each guide hole (214) is provided with a guide rod (215) and a return spring (23).

9. The lead screw thread measuring instrument with anti-collision structure as described in claim 8, characterized in that: One of the guide holes (214) passes through the protective sleeve (213) and the protective cover (22). The guide rod (215) located in the guide hole (214) serves as a push rod (25), and its end away from the protective cover (22) can touch the micro switch (24).

10. The screw thread measuring instrument with anti-collision structure as described in any one of claims 6-9, characterized in that: The protective cover (22) has a limiting through hole (221) on its side, and the protective sleeve (213) has a limiting post (216) that passes through the limiting through hole (221).

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