Portable shaft diameter contour point measuring device and calibration method thereof

Abstract

The invention relates to the technical field of contour point measurement, in particular to a portable shaft diameter contour point measuring device and a calibration method thereof, and the measuring device comprises a housing, a driving mechanism, a transmission mechanism, a mobile detection mechanism, a positioning mechanism, a display mechanism and a control system. The shell is provided with an opening; the driving mechanism, the mobile detection mechanism and the display mechanism are installed outside the shell, the transmission mechanism and the mobile detection mechanism are installed inside the shell, and the positioning mechanism is arranged on the opening side of the shell, connected with the shell and used for positioning a detected shaft; the transmission mechanism is respectively connected with the driving mechanism and the mobile detection mechanism, the driving mechanism drives the transmission mechanism and drives the mobile detection mechanism to reciprocate, and the mobile detection mechanism acquires the diameter contour point cloud data of the detected shaft. The device has the advantages that through the driving mechanism, the transmission mechanism and the mobile detection mechanism, the diameter contour point measurement of the detected shaft can be realized without manual contact, and the requirements of on-site rapid detection and intelligent evaluation are met.

Description

Technical Field

[0001] The present invention relates to the technical field of contour point measurement, and in particular to a portable shaft diameter contour point measuring device and a calibration method thereof. Background Art

[0002] With the rapid development of my country's rail transportation industry, the machining quality requirements for EMU axles are becoming increasingly stringent. Not only must the reliability of their internal structures be ensured, but the shape, dimensions, and appearance must also be strictly controlled. Axle machining accuracy (especially geometric tolerances and length errors) is a key indicator of production process quality, directly impacting axle assembly quality and operational safety.

[0003] Currently, axle measurement primarily relies on contact tools such as vernier calipers. While these tools can provide basic axle diameter measurement, they suffer from low efficiency, high labor intensity, and significant human error in batch testing, making them difficult to meet the high-efficiency, high-precision measurement demands of modern production. In recent years, non-contact measurement technologies (such as laser scanning, light curtain visual inspection, and laser ranging sensors) have been gradually applied to axle inspection, enabling 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 adoption in production settings. Summary of the Invention

[0004] In light of this, the present invention aims to provide a portable shaft diameter profile point measurement device and its calibration method. This device can measure the profile points of the shaft diameter without human interaction, meeting the needs of rapid on-site inspection and intelligent assessment. With its compact structure and simple operation, it is suitable for portable applications during shaft machining and quality inspection, effectively enhancing the automation, intelligence, and practicality of shaft inspection.

[0005] To achieve the above-mentioned purpose, the technical solution created by the present invention is implemented as follows: a portable shaft diameter contour point measuring device, comprising: a shell, a driving mechanism, a transmission mechanism, a mobile detection mechanism, a positioning mechanism and a display mechanism; an opening is provided at the bottom of the shell; the transmission mechanism and the mobile detection mechanism are arranged inside the shell; the driving mechanism comprises a driving part provided outside the shell and a transmission part extending into the shell, the transmission part is connected to the input end of the transmission mechanism; the output end of the transmission mechanism is connected to the mobile detection mechanism; the positioning mechanism is connected to the shell, located on the opening side of the shell, and is used to guide the measured shaft to achieve radial positioning; the display mechanism is arranged on the upper surface of the shell and is electrically connected to the mobile detection mechanism; the driving part drives the transmission mechanism to rotate through the transmission part, driving the mobile detection mechanism to perform reciprocating motion, and the mobile detection mechanism obtains the diameter contour point cloud data of the measured shaft 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 is meshed 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 are meshed with each other; a first sector gear is provided on the first gear, and a second sector gear is provided on the second gear, and the first sector gear and the second sector gear are arranged back to back; the rack is meshed with the first sector gear or the second sector gear.

[0007] Furthermore, a first mounting plate and a second mounting plate are arranged at intervals in the shell; the worm and the worm wheel are arranged between the first mounting plate and the second mounting plate; the first gear, the second gear and the rack are arranged 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, and the second connecting shaft is respectively connected to 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 respectively connected to the slider and rack of the linear guide rail; and multiple sensors are arranged 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, and the two positioning plates have inclined surfaces on opposite sides, and a conical space is formed between the two inclined surfaces for guiding the measured shaft to achieve radial positioning.

[0012] Furthermore, the display mechanism includes a mounting frame, a display screen and a pair of handles. The mounting frame is connected to the shell. The display screen and the pair of handles are both arranged on the mounting frame. The pair of handles are located on both sides of the display screen.

[0013] A calibration method for a portable shaft diameter profile point measuring device is provided, and is used to calibrate the portable shaft diameter profile point measuring device, comprising the following steps: S1: Create a calibration block, the outline of which includes at least three straight line segments.

[0014] S2: Use a portable shaft diameter contour point measurement device to obtain the contour point cloud data of the calibration block.

[0015] S3: Select the starting point A and the adjacent point B from the contour points, and fit the equation of the straight line AB based on the least squares method to obtain the slope 1.

[0016] S4: Select the next point C of point B and fit the equation of line BC using the least squares method to obtain its slope. 2.

[0017] S5: Calculate the slope difference Δk between line AB and line BC; if Δk is less than or equal to a preset threshold value k, determine that point A, point B, and point C are collinear.

[0018] S6: Continue to iteratively add subsequent points, refit the line based on the least squares method and calculate the distance between two adjacent lines. , until Δk is greater than the preset threshold k, the current fitted straight line equation is recorded as the first straight line segment.

[0019] S7: Taking the end point of the first straight line segment as a new starting point, repeat steps S3 to S6 until the straight line segment recognition of the entire contour is completed.

[0020] S8: Calculate the height of all fitted straight lines based on the bottom surface of the gauge block. If the height measurement values ​​of each straight line segment are within the allowable error range, the calibration is considered qualified.

[0021] The invention can achieve the following beneficial effects: 1) The measuring device of this invention utilizes a drive mechanism, a transmission mechanism, and a mobile detection mechanism to measure the diameter contour points of a shaft without human interaction, meeting the requirements for rapid on-site testing and intelligent assessment. Its compact structure and ease of operation make it suitable for portable applications during shaft machining and quality inspection, effectively enhancing the automation, intelligence, and practicality of shaft testing.

[0022] 2) Calibrate the measuring device by using a calibration block to make the measuring accuracy of the measuring device more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 2. It is a schematic structural diagram of a portable shaft diameter profile point measuring device and a shaft to be measured provided in accordance with an embodiment of the present invention; Figure 2 This is a schematic structural diagram of a portable shaft diameter profile point measuring device provided by an embodiment of the present invention with one side of the housing removed; Figure 3 2 is a schematic diagram of a structure in which a driving mechanism and a transmission mechanism provided in an embodiment of the present invention are respectively installed on a first mounting plate and a second mounting plate; Figure 4 is a structural schematic diagram of a driving mechanism and a transmission mechanism provided according to an embodiment of the present invention; Figure 5 is a structural diagram of a movement detection mechanism provided according to an embodiment of the present invention; Figure 6 is a structural schematic diagram of a positioning mechanism provided according to an embodiment of the present invention; Figure 7 is a schematic structural diagram of a calibration block provided according to an embodiment of the present invention; Figure 8 is a schematic diagram of a point cloud of a calibration block provided according to an embodiment of the present invention; Figure 9 Schematic diagram of a straight line point cloud after fitting the calibration block point cloud provided by an embodiment of the present invention.

[0024] The accompanying drawings include: 1. housing; 11. first mounting plate; 12. second mounting plate; 2. driving mechanism; 21. motor; 22. worm; 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; 42. connecting plate; 43. sensor; 5. positioning mechanism; 51. positioning mounting plate; 52. positioning plate; 6. display mechanism; 61. mounting frame; 62. display screen; 63. handle; 7. measured shaft; 8. calibration block. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is 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 only used to explain the present invention and do not constitute a limitation of the present invention.

[0026] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations 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, the terms "first", "second" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined as "first", "second" and the like 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.

[0028] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0029] The present invention will be described in detail below with reference to the embodiments.

[0030] like Figures 1 to 6 As shown, an embodiment of the present invention provides a portable shaft diameter profile point measuring device, which includes: a housing 1, a driving mechanism 2, a transmission mechanism 3, a movement detection mechanism 4, a positioning mechanism 5 and a display mechanism 6.

[0031] The housing 1 is used to install the driving mechanism 2, the transmission mechanism 3, the movement detection mechanism 4, the positioning mechanism 5 and the display mechanism 6. The bottom of the housing 1 is provided with an opening, and a first mounting plate 11 and a second mounting plate 12 are provided in the housing 1 at intervals.

[0032] The transmission mechanism 3 and the movement detection mechanism 4 are arranged inside the housing 1. The transmission mechanism 3 is connected to the first mounting plate 11 and the second mounting plate 12, and the movement detection mechanism 4 is connected to the second mounting plate 12. The housing 1 protects the transmission mechanism 3 and the movement detection mechanism 4.

[0033] Drive mechanism 2 includes a drive portion located outside housing 1 and a transmission portion extending into housing 1. The transmission portion is connected to the input of transmission mechanism 3. The output of transmission mechanism 3 is connected to movement detection mechanism 4. Positioning mechanism 5 is connected to housing 1 and located on the open side of housing 1. It is used to guide the measured shaft 7 for radial positioning. Display mechanism 6 is provided on the upper surface of housing 1 and is electrically connected to movement detection mechanism 4.

[0034] The driving unit drives the transmission mechanism 3 to rotate through the transmission unit, driving the mobile detection mechanism 4 to reciprocate, and the mobile detection mechanism 4 obtains the diameter contour point cloud data of the measured shaft 7 in real time. The display mechanism 6 outputs the measurement results.

[0035] The drive mechanism 2 comprises a motor 21 as the driving portion and a worm 22 as the transmission portion. The output shaft of the motor 21 is connected to one end of the worm 22 via a coupling. The other end of the worm 22 is rotatably connected to the first mounting plate 11 via a bearing and a fixed block. The fixed end of the motor 21 is connected to the housing 1 via a mounting base.

[0036] 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, serving as the input of the transmission mechanism 3, meshes with the worm 22. The first gear 32 and the worm gear 31 are connected 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 provided on the first gear 32, and a second sector gear 37 is provided on the second gear 33. The first sector gear 36 and the second sector gear 37 are arranged opposite 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 of the transmission mechanism 3. Through meshing with the rack 34, they drive the mobile detection mechanism 4 to achieve reciprocating linear motion.

[0037] Specifically, the worm 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 outside the second mounting plate, with the rack 34 mounted on the second mounting plate 12. One end of a 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.

[0038] 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.

[0039] The transmission mechanism 3 is integrated into a compact space and rationally arranged using the first mounting plate 11 and the second mounting plate 12, making the entire transmission mechanism 3 small and compact, suitable for use in limited spaces. The multi-stage reduction of the worm gear and gear drive enables a large reduction ratio, thereby outputting a large torque with a small input torque, meeting application scenarios with high torque requirements. The first sector gear 36 and the second sector gear 37 are arranged in opposite directions, and the rack 34 can mesh with the first sector gear 36 or the second sector gear 37. This design provides flexible motion control. Different motion directions can be achieved by selecting different sector gears.

[0040] The motion detection mechanism 4 includes a linear guide 41, a connecting plate 42, and a plurality of sensors 43. The linear guide 41 is connected to the second mounting plate 12 and is located below the rack 34. The connecting plate 42 is connected to the slider of the linear guide 41 and the rack 34 respectively. The plurality of sensors 43 are disposed on the connecting plate 42.

[0041] There are three sensors 43, and they are not aligned in a straight line. This arrangement enables the three sensors 43 to collect data at different ranges, thus covering a wider area. This allows for comprehensive acquisition of 180° cross-sectional data, significantly improving detection accuracy.

[0042] In this embodiment, three sensors 43 are arranged in a herringbone pattern. This arrangement enables the sensors 43, driven by the transmission mechanism 3, to acquire contour point cloud data for half of the measured shaft 7, thereby satisfying the contour point acquisition requirement. In another embodiment, the measured shaft 7 is flipped 180°, and contour point cloud data for the other half of the circle is measured, thereby acquiring contour point cloud data for the entire cross-section of the measured shaft 7.

[0043] The positioning mechanism 5 includes a positioning mounting plate 51 and two positioning plates 52 mounted on it. The positioning mounting plate 51 is attached to the bottom surfaces of the first mounting plate 11 and the second mounting plate 12, and is connected to each other. The two positioning plates 52 have inclined surfaces on their opposing sides, forming a tapered space that guides the measured shaft 7 for automatic centering. This tapered space accommodates measured shafts 7 of varying diameters, enabling precise positioning.

[0044] The display mechanism 6 includes a mounting frame 61, a display screen 62, and two handles 63. The mounting frame 61 is connected to the upper surface of the housing 1. The display screen 62 and handles 63 are both mounted on the mounting frame 61. The display screen 62 is electrically connected to the three sensors 43. The two handles 63 are located on either side of the display screen 62. The handles 63 facilitate operation by the operator.

[0045] like Figures 7 to 9As shown, a calibration method for a portable shaft diameter profile point measuring device is used to calibrate the above-mentioned portable shaft diameter profile point measuring device, comprising the following steps: S1: Prepare a calibration block 8, whose outline 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 second straight line segment is higher than the first and third straight line segments, and the first and third straight line segments are located at the same height.

[0046] S2: Use a portable shaft diameter contour point measuring device to obtain contour point cloud data of the calibration block 8.

[0047] Specifically, the driving mechanism 2 drives the transmission mechanism 3 , which drives the mobile detection mechanism 4 to perform reciprocating motion along the calibration block 8 , and the three sensors 43 acquire the diameter contour point cloud data of the calibration block 8 in real time.

[0048] S3: Select the starting point A and the adjacent point B from the contour points, and fit the equation of the straight line AB based on the least squares method. , and get the slope .

[0049] Where y represents the vertical coordinate of any point on the line, and x represents the horizontal coordinate of any point on the line. represents the slope of line AB, The coordinates of point A and point B can be obtained by ( x A ，y A ) 、 ( x B， y B ) is calculated, that is . b represents the intercept of the line segment on the y-axis.

[0050] S4: Select the next point C of 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.

[0051] S5: Calculate the slope difference Δk between line AB and line 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 based on actual conditions.

[0052] Specifically, the preset 1 =tanα and 2 =tanβ , then the difference in slope between line AB and line BC is If the Δk value is less than the preset threshold k, then points A, B, and C are determined to be collinear.

[0053] S6: Continue to iteratively add subsequent points, refit the line based on the least squares method and calculate the distance between two adjacent lines. , until Δk is greater than the preset threshold k, the current fitted straight line equation is recorded as the first straight line segment.

[0054] S7: Taking the end point of the first straight line segment as a new starting point, repeat steps S3 to S6, fitting all straight line equations segment by segment until the entire point cloud is traversed.

[0055] S8: Calculate the height of all fitted straight lines based on the bottom surface of the gauge block. If the height measurement values ​​of each straight line segment are within the allowable error (±0.0025), the calibration is considered qualified.

[0056] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A portable shaft diameter profile point measuring device, characterized in that: include: Housing, driving 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 provided inside the housing; The driving mechanism includes a driving portion provided outside the housing and a transmission portion extending into the housing, wherein the transmission portion is connected to an input end of the transmission mechanism; and an output end of the transmission mechanism is connected to the movement detection mechanism; The positioning mechanism is connected to the housing and is located on the opening side of the housing, and is used to guide the measured shaft to achieve radial positioning; The display mechanism is arranged on the upper surface of the housing and is electrically connected to the movement detection mechanism; The driving unit drives the transmission mechanism to rotate through the transmission unit, driving the mobile detection mechanism to perform reciprocating motion. The mobile detection mechanism obtains the point cloud data of the diameter contour of the measured shaft in real time; the display mechanism outputs the measurement result.

2. The portable shaft diameter profile point measuring device according to claim 1, characterized in that: 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 is meshed with the worm, the first gear is connected to the worm wheel via a first connecting shaft, and the first gear and the second gear are meshed with each other; The first gear is provided with a first sector gear, the second gear is provided with a second sector gear, and the first sector gear and the second sector gear are arranged opposite to each other; the rack is meshed with the first sector gear or the second sector gear.

3. The portable shaft diameter profile point measuring device according to claim 2, characterized in that: A first mounting plate and a second mounting plate are spaced apart in the shell; The worm and the worm wheel are arranged between the first mounting plate and the second mounting plate; the first gear, the second gear and the rack are arranged on the outer side 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.

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

5. The portable shaft diameter profile point measuring device according to claim 3, characterized in that: The movement 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 respectively connected to the slider of the linear guide rail and the rack; and multiple sensors are arranged on the connecting plate.

6. The portable shaft diameter profile point measuring device according to claim 5, characterized in that: There are three sensors, and the three sensors are not on the same straight line.

7. The portable shaft diameter profile point measuring device according to claim 1, characterized in that: The positioning mechanism includes two positioning plates. The two positioning plates have inclined surfaces on opposite sides. A conical space is formed between the two inclined surfaces for guiding the measured shaft to achieve radial positioning.

8. 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 shell. The display screen and the pair of handles are both arranged on the mounting frame. The pair of handles are located on both sides of the display screen.

9. A calibration method for a portable shaft diameter profile point measuring device, used for calibrating the portable shaft diameter profile point measuring device according to any one of claims 1 to 8, characterized in that: The steps include: S1: Make a calibration block, the outline of which includes at least three straight line segments; S2: Use a portable shaft diameter contour point measurement device to obtain the contour point cloud data of the calibration block; S3: Select the starting point A and the adjacent point B from the contour points, and fit the equation of the straight line AB based on the least squares method to obtain the slope 1; S4: Select the next point C of 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 line AB and line BC; if the slope difference Δk is less than or equal to a preset threshold value k, then determine that point A, point B, and point C are collinear; S6: Continue to iteratively add subsequent points, refit the line based on the least squares method and calculate the slope difference between two adjacent lines , until the slope difference Δk is greater than the preset threshold k, the current fitted straight line equation is recorded as the first straight line segment; S7: Using the end point of the first straight line segment as a new starting point, repeat steps S3 to S6 until the straight line segment recognition of the entire contour is completed; S8: Calculate the height of all fitted straight lines based on the bottom surface of the gauge block. If the height measurement values ​​of each straight line segment are within the allowable error range, the calibration is considered qualified.

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