Portable shaft diameter profile point measuring device and its calibration method

Abstract

This invention relates to the field of contour point measurement technology, and more particularly to a portable shaft diameter contour point measuring device and its calibration method. The measuring device includes: a housing, a drive mechanism, a transmission mechanism, a moving detection mechanism, a positioning mechanism, a display mechanism, and a control system. The housing has an opening. The drive mechanism, moving detection mechanism, and display mechanism are installed outside the housing, while the transmission mechanism and moving detection mechanism are installed inside the housing. The positioning mechanism is located on the opening side of the housing and connected to the housing for positioning the shaft being measured. The transmission mechanism connects to both the drive mechanism and the moving detection mechanism. The drive mechanism drives the transmission mechanism, causing the moving detection mechanism to reciprocate. The moving detection mechanism acquires the contour point cloud data of the shaft diameter being measured. The advantage of this invention is that it enables the measurement of the shaft diameter contour points without manual contact through the drive mechanism, transmission mechanism, and moving detection mechanism, meeting the needs of rapid on-site detection and intelligent evaluation.

Description

Technical Field

[0001] This invention relates to the field of profile point measurement technology, and in particular to a portable shaft diameter profile point measuring device and its calibration method. Background Technology

[0002] With the rapid development of my country's rail transportation industry, the processing quality requirements for train axles are becoming increasingly stringent. Not only must the reliability of their internal structure be ensured, but also the shape, dimensions, and appearance accuracy must be strictly controlled. Axle processing accuracy (especially geometric tolerances and length errors) is a key indicator for measuring the level of manufacturing technology and directly affects the assembly quality and operational safety of the axles.

[0003] Currently, axle measurement mainly relies on contact tools such as vernier calipers. While these tools can achieve basic axle diameter measurements, they suffer from low efficiency, high labor intensity, and significant human error in batch inspections, making it difficult to meet the demands of modern production for efficient and high-precision measurement. In recent years, non-contact measurement technologies (such as laser scanning, light curtain vision inspection, and laser rangefinders) have been gradually applied to the axle inspection field, achieving automated measurement of axle cross-sectional shape and dimensions. However, existing non-contact measurement systems are mostly specialized equipment, complex to operate, and require high technical skills from workshop workers, hindering their widespread application in production sites. Summary of the Invention

[0004] In view of this, the present invention aims to provide a portable shaft diameter profile point measuring device and its calibration method. This measuring device can measure the profile point of the shaft diameter without manual contact, meeting the needs of rapid on-site inspection and intelligent evaluation. It features a compact structure and simple operation, making it suitable for portable applications in the machining process and quality inspection of the shaft being measured, effectively improving the automation, intelligence, and practicality of shaft inspection.

[0005] To achieve the above objectives, the technical solution of this invention is implemented as follows: A portable shaft diameter profile point measuring device includes: a housing, a drive mechanism, a transmission mechanism, a moving detection mechanism, a positioning mechanism, and a display mechanism; the bottom of the housing is provided with an opening; the transmission mechanism and the moving detection mechanism are disposed inside the housing; the drive mechanism includes a drive part disposed outside the housing and a transmission part extending into the housing, the transmission part being connected to the input end of the transmission mechanism; the output end of the transmission mechanism is connected to the moving detection mechanism; the positioning mechanism is connected to the housing and located on the opening side of the housing, used to guide the measured shaft to achieve radial positioning; the display mechanism is disposed on the upper surface of the housing and electrically connected to the moving detection mechanism; the drive part drives the transmission mechanism to rotate through the transmission part, driving the moving detection mechanism to reciprocate, and the moving detection mechanism acquires the measured shaft diameter profile point cloud data in real time; the display mechanism outputs the measurement results.

[0006] Furthermore, the transmission part is a worm; the transmission mechanism includes a worm wheel, a first gear, a second gear, and a rack; the worm wheel meshes with the worm, the first gear is connected to the worm wheel through a first connecting shaft, and the first gear and the second gear mesh with each other; a first sector gear is provided on the first gear, and a second sector gear is provided on the second gear, with the first sector gear and the second sector gear arranged opposite to each other; the rack meshes with either the first sector gear or the second sector gear.

[0007] Furthermore, a first mounting plate and a second mounting plate are spaced apart inside the housing; a worm and a worm wheel are disposed between the first mounting plate and the second mounting plate; a first gear, a second gear, and a rack are disposed on the outside of the second mounting plate, and the rack is mounted on the second mounting plate; one end of the first connecting shaft passes through the worm wheel and is rotatably connected to the first mounting plate; the other end of the first connecting shaft passes through the second mounting plate and is connected to the first gear, and is rotatably connected to the second mounting plate.

[0008] Furthermore, the second gear is rotatably connected to the second connecting shaft, which is connected to both the first mounting plate and the second mounting plate.

[0009] Furthermore, the mobile detection mechanism includes a linear guide rail, a connecting plate, and multiple sensors. The linear guide rail is connected to the second mounting plate and is located below the rack. The connecting plate is connected to the slider and rack of the linear guide rail respectively. Multiple sensors are mounted on the connecting plate.

[0010] Furthermore, there are three sensors, and the three sensors are not on the same straight line.

[0011] Furthermore, the positioning mechanism includes two positioning plates, each with an inclined surface on one side facing the other, forming a conical space between the two inclined surfaces to guide the measured shaft for radial positioning.

[0012] Furthermore, the display mechanism includes a mounting bracket, a display screen, and a pair of handles. The mounting bracket is connected to the housing, and the display screen and the pair of handles are both mounted on the mounting bracket, with the pair of handles located on both sides of the display screen.

[0013] A calibration method for a portable shaft diameter profile point measuring device, used to calibrate the aforementioned portable shaft diameter profile point measuring device, includes the following steps:

[0014] S1: Create a calibration block whose outline includes at least three straight line segments.

[0015] S2: Use a portable shaft diameter profile point measuring device to acquire the profile point cloud data of the calibration block.

[0016] S3: Select starting point A and adjacent point B from the contour points, and fit the equation of line AB using the least squares method to obtain the slope. 1.

[0017] S4: Select point C, the next point after point B, and fit the equation of line BC using the least squares method to obtain its slope. 2.

[0018] S5: Calculate the slope difference Δk between lines AB and BC; if Δk is less than or equal to the preset threshold k, then determine that points A, B and C are collinear.

[0019] S6: Continue iterating by adding subsequent points, refitting the line based on the least squares method, and calculating the values ​​of adjacent lines. Continue until Δk is greater than the preset threshold k, then record the equation of the currently fitted line as the first line segment.

[0020] S7: Using the end point of the first straight line segment as the new starting point, repeat steps S3-S6 until the straight line segment recognition of the entire contour is completed.

[0021] S8: Using the bottom surface of the gauge block as a reference, calculate the height values ​​of all fitted straight lines. If the height measurements of each straight line segment are within the allowable error range, the calibration is deemed qualified.

[0022] The present invention can achieve the following beneficial effects:

[0023] 1) The measuring device of the present invention can measure the diameter profile of the shaft being measured without manual contact through the drive mechanism, transmission mechanism, and moving detection mechanism, meeting the needs of rapid on-site inspection and intelligent evaluation. It has a compact structure and is easy to operate, making it suitable for portable applications in the machining process and quality inspection of the shaft being measured, effectively improving the automation, intelligence, and practicality of shaft inspection.

[0024] 2) The measurement accuracy of the measuring device is improved by calibrating the calibration block. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the portable shaft diameter profile point measuring device and the shaft being measured according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the portable shaft diameter profile point measuring device provided according to an embodiment of the present invention after removing one side of the outer casing;

[0028] Figure 3 This is a schematic diagram of the structure provided by the embodiment of the present invention, showing the drive mechanism and transmission mechanism respectively mounted on the first mounting plate and the second mounting plate;

[0029] Figure 4 This is a schematic diagram of the drive mechanism and transmission mechanism provided according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the mobile detection mechanism provided in an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the positioning mechanism provided according to an embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of the structure of a calibration block provided according to an embodiment of the present invention;

[0033] Figure 8 This is a point cloud diagram of a calibration block provided according to an embodiment of the present invention;

[0034] Figure 9 This is a schematic diagram of a straight line point cloud after fitting a calibrated block point cloud according to an embodiment of the present invention.

[0035] The reference numerals in the accompanying drawings include: 1. Housing; 11. First mounting plate; 12. Second mounting plate; 2. Drive mechanism; 21. Motor; 22. Worm gear; 3. Transmission mechanism; 31. Worm wheel; 32. First gear; 33. Second gear; 34. Rack; 35. First connecting shaft; 36. First sector gear; 37. Second sector gear; 38. Second connecting shaft; 4. Moving detection mechanism; 41. Linear guide rail; 42. Connecting plate; 43. Sensor; 5. Positioning mechanism; 51. Positioning mounting plate; 52. Positioning plate; 6. Display mechanism; 61. Mounting bracket; 62. Display screen; 63. Handle; 7. Measured shaft; 8. Calibration block. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] The invention will now be described in detail with reference to specific embodiments.

[0041] like Figures 1 to 6 As shown in the figure, a portable shaft diameter profile point measuring device provided in this embodiment of the invention includes: a housing 1, a driving mechanism 2, a transmission mechanism 3, a moving detection mechanism 4, a positioning mechanism 5, and a display mechanism 6.

[0042] The housing 1 is used to mount the drive mechanism 2, transmission mechanism 3, movement detection mechanism 4, positioning mechanism 5, and display mechanism 6. The bottom of the housing 1 has an opening, and a first mounting plate 11 and a second mounting plate 12 are spaced apart inside the housing 1.

[0043] The transmission mechanism 3 and the moving detection mechanism 4 are disposed inside the housing 1. The transmission mechanism 3 is connected to the first mounting plate 11 and the second mounting plate 12, and the moving detection mechanism 4 is connected to the second mounting plate 12. The housing 1 protects the transmission mechanism 3 and the moving detection mechanism 4.

[0044] The drive mechanism 2 includes a drive unit located outside the housing 1 and a transmission unit extending into the housing 1. The transmission unit is connected to the input end of the transmission mechanism 3. The output end of the transmission mechanism 3 is connected to the motion detection mechanism 4. The positioning mechanism 5 is connected to the housing 1 and located on the open side of the housing 1, used to guide the measured shaft 7 to achieve radial positioning. The display mechanism 6 is located on the upper surface of the housing 1 and is electrically connected to the motion detection mechanism 4.

[0045] The drive unit drives the transmission mechanism 3 to rotate via the transmission unit, which in turn drives the moving detection mechanism 4 to reciprocate. The moving detection mechanism 4 acquires the point cloud data of the diameter contour of the measured shaft 7 in real time. The display mechanism 6 outputs the measurement results.

[0046] The drive mechanism 2 has a motor 21 as its drive unit and a worm gear 22 as its transmission unit. The output shaft of the motor 21 is connected to one end of the worm gear 22 via a coupling. The other end of the worm gear 22 is rotatably connected to the first mounting plate 11 via a bearing and a fixing block. The fixed end of the motor 21 is connected to the housing 1 via a mounting base.

[0047] The transmission mechanism 3 includes a worm gear 31, a first gear 32, a second gear 33, and a rack 34. The worm gear 31 serves as the input end of the transmission mechanism 3 and meshes with the worm 22. The first gear 32 is connected to the worm gear 31 via a first connecting shaft 35, and the first gear 32 and the second gear 33 mesh with each other. A first sector gear 36 is mounted on the first gear 32, and a second sector gear 37 is mounted on the second gear 33. The first sector gear 36 and the second sector gear 37 are arranged opposite to each other, and the rack 34 meshes with either the first sector gear 36 or the second sector gear 37. The first sector gear 36 and the second sector gear 37 constitute the output end of the transmission mechanism 3, and through meshing with the rack 34, drive the moving detection mechanism 4 to achieve reciprocating linear motion.

[0048] Specifically, the worm gear 22 and worm wheel 31 are disposed between the first mounting plate 11 and the second mounting plate 12. The first gear 32, the second gear 33, and the rack 34 are disposed on the outer side of the second mounting plate, and the rack 34 is mounted on the second mounting plate 12. One end of the first connecting shaft 35 passes through the worm wheel 31 and is rotatably connected to the first mounting plate 11 via a bearing. The other end of the first connecting shaft 35 passes through the second mounting plate 12 and is connected to the first gear 32, and is rotatably connected to the second mounting plate 12 via a bearing.

[0049] The second gear 33 is rotatably connected to the second connecting shaft 38 via a bearing. The second connecting shaft 38 is connected to the first mounting plate 11 and the second mounting plate 12 respectively.

[0050] The transmission mechanism 3 is integrated into a compact space, with a reasonable layout achieved through the first mounting plate 11 and the second mounting plate 12. This makes the entire transmission mechanism 3 small in size and compact in structure, suitable for use in confined spaces. Through multi-stage reduction via worm gear and gear transmission, a large reduction ratio can be achieved, thus outputting a large torque with a relatively small input torque, meeting the needs of high-torque applications. The first sector gear 36 and the second sector gear 37 are arranged in opposite directions, and the rack 34 can mesh with either the first sector gear 36 or the second sector gear 37. This design provides flexible motion control. Different directions of motion can be achieved by selecting different sector gears.

[0051] The mobile detection mechanism 4 includes a linear guide rail 41, a connecting plate 42, and multiple sensors 43. The linear guide rail 41 is connected to the second mounting plate 12 and is located below the rack 34. The connecting plate 42 is connected to both the slider of the linear guide rail 41 and the rack 34. The multiple sensors 43 are mounted on the connecting plate 42.

[0052] There are three sensors 43, which are not aligned in a straight line. This arrangement allows the three sensors 43 to acquire data at different ranges, thus covering a wider area. It enables comprehensive acquisition of cross-sectional data at 180°, significantly improving detection accuracy.

[0053] In this embodiment, the three sensors 43 are arranged in a triangular pattern. This arrangement allows the sensors 43, driven by the transmission mechanism 3, to acquire the contour point cloud data of half a circle of the measured shaft 7, thus meeting the requirements for contour point acquisition. In another embodiment, the measured shaft 7 is rotated 180°, and the contour point cloud data of the other half of the circle is then measured, thereby acquiring the contour point cloud data of the entire cross-sectional circle of the measured shaft 7.

[0054] The positioning mechanism 5 includes a positioning mounting plate 51 and two positioning plates 52 mounted on the positioning mounting plate 51. The positioning mounting plate 51 is mounted on the bottom surface of the first mounting plate 11 and connected to the bottom surface of the second mounting plate 12. The two positioning plates 52 have inclined surfaces on opposite sides, forming a conical space to guide the measured shaft 7 to achieve automatic centering and positioning. The conical space can accommodate measured shafts 7 of different diameters, achieving precise positioning.

[0055] The display mechanism 6 includes a mounting bracket 61, a display screen 62, and two handles 63. The mounting bracket 61 is connected to the upper surface of the housing 1. The display screen 62 and the handles 63 are both mounted on the mounting bracket 61. The display screen 62 is electrically connected to three sensors 43. The two handles 63 are located on both sides of the display screen 62. The handles 63 facilitate operation by the operator.

[0056] like Figures 7 to 9As shown, a calibration method for a portable shaft diameter profile point measuring device, used to calibrate the aforementioned portable shaft diameter profile point measuring device, includes the following steps:

[0057] S1: Fabricate a calibration block 8, the outline of which includes at least three straight line segments. In this embodiment, the calibration block 8 includes a first straight line segment, a second straight line segment, and a third straight line segment, wherein the height of the second straight line segment is higher than that of the first and third straight line segments, and the first and third straight line segments are at the same height.

[0058] S2: Use a portable shaft diameter profile point measuring device to acquire the profile point cloud data of calibration block 8.

[0059] Specifically, the drive mechanism 2 drives the transmission mechanism 3, which in turn drives the moving detection mechanism 4 to reciprocate along the calibration block 8. The three sensors 43 acquire the point cloud data of the diameter contour of the calibration block 8 in real time.

[0060] S3: Select a starting point A and an adjacent point B from the contour points, and fit the equation of line AB using the least squares method. To obtain the slope .

[0061] Where y represents the ordinate of any point on the line, and x represents the abscissa of any point on the line. This represents the slope of line AB. We can use the coordinates of points A and B ( x A ，y A ) 、 ( x B， y B ) is calculated to be, i.e. b represents the y-intercept of the line segment.

[0062] S4: Select point C, the next point after point B, and fit the equation of line BC using the least squares method to obtain its slope. 2; 2 same The calculation method is the same, and will not be described in detail here.

[0063] S5: Calculate the slope difference Δk between lines AB and BC; if Δk is less than or equal to a preset threshold k, then determine that points A, B, and C are collinear. The preset threshold k is not limited here and can be set according to the actual situation.

[0064] Specifically, preset 1 =tanα and 2 =tanβ Then the difference in slope between lines AB and BC If the value of Δk is less than the preset threshold k, then points A, B, and C are determined to be collinear.

[0065] S6: Continue iterating by adding subsequent points, refitting the line based on the least squares method, and calculating the values ​​of adjacent lines. Continue until Δk is greater than the preset threshold k, then record the equation of the currently fitted line as the first line segment.

[0066] S7: Using the end point of the first line segment as the new starting point, repeat steps S3-S6 to fit the equations of all lines segment by segment until the entire point cloud has been traversed.

[0067] S8: Using the bottom surface of the gauge block as a reference, calculate the height values ​​of all fitted straight lines. If the height measurement values ​​of each straight line segment are within the allowable error range (±0.0025), the calibration is deemed qualified.

[0068] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A portable shaft diameter profile point measuring device, characterized in that, include: Housing, drive mechanism, transmission mechanism, movement detection mechanism, positioning mechanism, and display mechanism; The bottom of the housing is provided with an opening; the transmission mechanism and the movement detection mechanism are located inside the housing; The drive mechanism includes a drive unit located outside the housing and a transmission unit extending into the housing. The transmission unit is connected to the input end of the transmission mechanism; the output end of the transmission mechanism is connected to the motion detection mechanism. The transmission part is a worm; the transmission mechanism includes a worm wheel, a first gear, a second gear, and a rack; the worm wheel meshes with the worm, the first gear is connected to the worm wheel through a first connecting shaft, and the first gear and the second gear mesh with each other; The first gear is provided with a first sector gear, and the second gear is provided with a second sector gear, with the first sector gear and the second sector gear being arranged opposite to each other; the rack meshes with the first sector gear or the second sector gear; The positioning mechanism is connected to the housing and is located on the open side of the housing, used to guide the measured shaft to achieve radial positioning; The display mechanism is disposed on the upper surface of the housing and is electrically connected to the moving detection mechanism; The drive unit drives the transmission mechanism to rotate through the transmission unit, thereby driving the mobile detection mechanism to reciprocate. The mobile detection mechanism acquires the point cloud data of the diameter contour of the measured shaft in real time; the display mechanism outputs the measurement results.

2. The portable shaft diameter profile point measuring device according to claim 1, characterized in that, The housing is provided with a first mounting plate and a second mounting plate at intervals. The worm and the worm wheel are disposed between the first mounting plate and the second mounting plate; the first gear, the second gear and the rack are disposed on the outside of the second mounting plate, and the rack is mounted on the second mounting plate; One end of the first connecting shaft passes through the worm gear and is rotatably connected to the first mounting plate; the other end of the first connecting shaft passes through the second mounting plate and is connected to the first gear, and is rotatably connected to the second mounting plate.

3. The portable shaft diameter profile point measuring device according to claim 2, characterized in that, The second gear is rotatably connected to the second connecting shaft, which is connected to the first mounting plate and the second mounting plate respectively.

4. The portable shaft diameter profile point measuring device according to claim 2, characterized in that, The moving detection mechanism includes a linear guide rail, a connecting plate, and multiple sensors. The linear guide rail is connected to the second mounting plate and is located below the rack. The connecting plate is connected to the slider of the linear guide rail and the rack. The multiple sensors are mounted on the connecting plate.

5. The portable shaft diameter profile point measuring device according to claim 4, characterized in that, The number of sensors is three, and the three sensors are not on the same straight line.

6. The portable shaft diameter profile point measuring device according to claim 1, characterized in that, The positioning mechanism includes two positioning plates, each with an inclined surface on one side facing the other, and a conical space between the two inclined surfaces, which is used to guide the measured shaft to achieve radial positioning.

7. The portable shaft diameter profile point measuring device according to claim 1, characterized in that, The display mechanism includes a mounting frame, a display screen, and a pair of handles. The mounting frame is connected to the housing. The display screen and the pair of handles are both mounted on the mounting frame, and the pair of handles are located on both sides of the display screen.

8. A calibration method for a portable shaft diameter profile point measuring device, used to calibrate the portable shaft diameter profile point measuring device according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Create a calibration block whose outline includes at least three straight line segments; S2: Use a portable shaft diameter profile point measuring device to acquire the profile point cloud data of the calibration block; S3: Select starting point A and adjacent point B from the contour points, and fit the equation of line AB using the least squares method to obtain the slope. 1; S4: Select point C, the next point after point B, and fit the equation of line BC using the least squares method to obtain its slope. 2; S5: Calculate the slope difference Δk between lines AB and BC; if the slope difference Δk is less than or equal to the preset threshold k, then determine that points A, B and C are collinear. S6: Continue iterating by adding subsequent points, refitting the line based on the least squares method, and calculating the slope difference between two adjacent lines. Continue until the slope difference Δk is greater than the preset threshold k, then record the equation of the currently fitted straight line as the first straight line segment; S7: Using the end point of the first straight line segment as the new starting point, repeat steps S3-S6 until the straight line segment recognition of the entire contour is completed. S8: Using the bottom surface of the gauge block as a reference, calculate the height values ​​of all fitted straight lines. If the height measurements of each straight line segment are within the allowable error range, the calibration is deemed qualified.

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