A small module gear tooth surface deviation measuring platform and method

Abstract

The application discloses a small-module gear tooth surface deviation measurement platform and method. The small-module gear tooth surface deviation measurement platform comprises a gear position adjustment module, a line laser sensor and a control module. The gear position adjustment module comprises a mounting part and a driving mechanism. The mounting part is provided with a reference cylindrical segment and is used for clamping and fixing a measured gear. The driving mechanism is used for driving the mounting part to rotate around the axis of the reference cylindrical segment and to move along the axial direction of the reference cylindrical segment. The line laser sensor is arranged on one side of the moving path of the mounting part. The control module is configured to perform the following operations: controlling the line laser sensor to collect surface profile point clouds of the reference cylindrical segment and local tooth surface profile point clouds of the measured gear; performing cylindrical fitting on the surface profile point clouds to obtain center axis parameters and establish a measurement coordinate system; and performing unified coordinate transformation on each local tooth surface profile point cloud and fusing the local tooth surface profile point clouds to obtain a full-tooth surface point cloud. The application can establish a rotary reference on line under single clamping condition and realize full-tooth surface point cloud reconstruction and deviation evaluation.

Description

Technical Field

[0001] This application relates to the field of gear measurement technology, and in particular to a platform and method for measuring the tooth surface deviation of small module gears. Background Technology

[0002] Due to their small tooth profile, narrow tooth space, and limited clamping reference, the measurement of the three-dimensional tooth surface morphology of small module gears places higher demands on the spatial arrangement, sampling accuracy, and coordinate unification capability of the measuring device. While existing contact measurement methods offer high accuracy, they suffer from low measurement efficiency, susceptibility to probe interference, and potential damage to the tooth surface. Existing optical non-contact measurement methods, although capable of acquiring multiple local point clouds through indexing rotation combined with line scanning, typically assume that the clamping axis, rotation axis, and indexing model are consistent during the fusion of these local point clouds. For small module gears, due to clamping eccentricity, clamping posture errors, and deviations between the actual indexing motion and the ideal model, such assumptions are difficult to fully accept. This leads to reference errors when fusing local point clouds acquired at each indexing position in a unified coordinate system, affecting the accuracy of full tooth surface reconstruction and the repeatability and reliability of tooth profile, tooth direction, and pitch deviation assessments. Furthermore, establishing a reference reference using offline calibration, additional targets, or secondary clamping not only increases the complexity of the measurement process but also makes it difficult to guarantee the consistency between the measurement reference and the actual rotation reference during a single clamping process. Therefore, there is an urgent need to propose a measurement platform and method for small module gears that can simultaneously establish a rotating reference and complete the acquisition of point clouds and deviation evaluation of the entire tooth surface under a single clamping condition. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a small module gear tooth surface deviation measurement platform, which can establish a rotational datum online under single clamping conditions and realize full tooth surface point cloud reconstruction and deviation evaluation.

[0004] This application also proposes a method for measuring the tooth surface deviation of small module gears.

[0005] According to an embodiment of the first aspect of this application, a small module gear tooth surface deviation measurement platform includes: A gear position adjustment module includes a mounting part and a drive mechanism. The mounting part has a reference cylindrical section and is used to clamp and fix the gear under test, and to make the reference cylindrical section and the gear under test coaxially spaced apart. The drive mechanism is used to drive the mounting part to rotate around the axis of the reference cylindrical section and to move along the axial direction of the reference cylindrical section. A line laser sensor is disposed on one side of the moving path of the mounting part; The control module is configured to perform the following operations: The drive mechanism is controlled to drive the mounting part to rotate in degree, and at each degree position, the mounting part is driven to move axially, so that the reference cylindrical section and the gear under test both pass through the measurement field of view of the line laser sensor. During the movement of the mounting part, the line laser sensor is controlled to acquire the surface contour point cloud of the reference cylindrical section and the local tooth surface contour point cloud of the gear under test. Cylindrical fitting is performed on the surface contour point cloud to obtain the central axis parameters of the reference cylindrical segment, and a measurement coordinate system is established based on the central axis parameters; Based on the measurement coordinate system and the actual angle values ​​corresponding to each of the indexing positions, the point clouds of each local tooth surface contour are subjected to a unified coordinate transformation and fused to obtain the full tooth surface point cloud of the gear under test.

[0006] The small module gear tooth surface deviation measurement platform according to the embodiments of this application has at least the following beneficial effects: Firstly, by setting reference cylindrical segments on the mounting part that are coaxially spaced with the gear under test, the line laser sensor can simultaneously acquire the local tooth surface contour point cloud of the gear under test and the surface contour point cloud of the reference cylindrical segment within the same linear scanning stroke. Thus, the surface contour point cloud of the reference cylindrical segment can be cylindrically fitted to obtain the central axis parameters of the actual rotation reference. Data acquisition and rotation reference establishment are completed synchronously under single clamping conditions, avoiding the reference offset error caused by offline calibration, additional targets or ideal clamping models. Secondly, the control module can establish a measurement coordinate system based on the central axis parameters, and combine the actual angle values ​​corresponding to each division position to unify the coordinates of each local tooth surface contour point cloud, so that each group of local point clouds can be mapped to the same physical rotation reference, reducing the fusion error of multi-division point clouds and improving the accuracy and repeatability of full tooth surface three-dimensional reconstruction. Third, the control module can register the reconstructed full tooth surface point cloud with the nominal tooth surface model of the gear under test and calculate the normal deviation, output the tooth profile deviation, tooth direction / helix deviation and tooth pitch deviation of the left and right tooth surfaces of all gear teeth, and realize the digital deviation assessment of the entire circumference and teeth of small module gears.

[0007] According to some embodiments of this application, the mounting part includes: A mandrel, wherein a mounting surface is provided at one end of the mandrel away from the driving mechanism, the mounting surface having threaded holes coaxially distributed with the reference cylindrical segment, the reference cylindrical segment being disposed on the mandrel; The positioning bolt includes a threaded connecting section, a positioning cylindrical section, and a head connected axially in sequence. The threaded connecting section is threaded into the threaded hole. The positioning cylindrical section passes through the central mounting hole of the gear under test to radially support and position the gear under test. The head abuts against the end face of the gear under test to press the gear under test against the mounting surface.

[0008] According to some embodiments of this application, the driving mechanism includes: A rotary drive unit is connected to the mounting unit for driving the mounting unit to rotate around the axis of the reference cylindrical segment. The rotary drive unit is equipped with an angle encoder. A mobile drive unit is connected to the rotary drive unit and is used to drive the rotary drive unit to move axially along the reference cylindrical segment. The mobile drive unit is equipped with a displacement encoder.

[0009] According to some embodiments of this application, the small module gear tooth surface deviation measurement platform further includes a multi-degree-of-freedom adjustment bracket for mounting the line laser sensor and adjusting the spatial position and angle of the line laser sensor.

[0010] The method for measuring the tooth surface deviation of small module gears according to the second aspect of this application, applied to the small module gear tooth surface deviation measurement platform of the above embodiment, includes the following steps: The drive mechanism is controlled to drive the mounting part, which clamps the gear under test, to rotate axially. At each indexed position, the drive mechanism is controlled to drive the mounting part to move axially. The line laser sensor is also controlled to collect the surface profile point cloud of the reference cylindrical section and the local tooth surface profile point cloud of the gear under test. Cylindrical fitting is performed on the surface profile point cloud at at least one of the indexing positions to obtain the central axis parameters of the reference cylindrical segment, and a measurement coordinate system is established based on the central axis parameters; Based on the measurement coordinate system and the actual angle values ​​corresponding to each of the indexing positions, the point clouds of each of the local tooth surface contours are subjected to a unified coordinate transformation and fused to obtain the full tooth surface point cloud of the gear under test. Based on the nominal geometric parameters of the gear under test, a nominal tooth surface model of the gear under test is established. The point cloud of the full tooth surface is registered with the nominal tooth surface model, and then the normal deviation of the point cloud of the full tooth surface relative to the nominal tooth surface model is calculated.

[0011] According to some embodiments of this application, the drive mechanism is equipped with a displacement encoder, and the control of the line laser sensor to acquire the surface contour point cloud of the reference cylindrical segment and the local tooth surface contour point cloud of the gear under test includes: Based on the displacement feedback signal from the displacement encoder, the line laser sensor is controlled to collect the surface contour point cloud of the reference cylindrical segment and the local tooth surface contour point cloud of the gear under test at equal intervals.

[0012] According to some embodiments of this application, the step of performing cylindrical fitting on the surface profile point cloud at at least one of the indexing positions to obtain the central axis parameters of the reference cylindrical segment includes: Cylindrical fitting is performed on the surface profile point cloud at the initial indexing position to obtain the central axis parameters of the reference cylindrical segment; Alternatively, cylindrical fitting can be performed on the surface contour point clouds at multiple indexing positions to obtain the central axis parameters of the reference cylindrical segment at multiple indexing positions, and then averaging or least squares processing can be performed to obtain the final central axis parameters of the reference cylindrical segment.

[0013] According to some embodiments of this application, the step of performing a unified coordinate transformation and fusion on the local tooth surface contour point clouds based on the measurement coordinate system and the actual angle values ​​corresponding to each of the graduation positions includes: Transform the local tooth surface contour point cloud at each of the specified indexing positions to the measurement coordinate system; Based on the actual angle value corresponding to each of the indexing positions, the converted local tooth surface contour point cloud is rotated around the axis corresponding to the central axis parameter to a unified reference angle position. The point clouds of the local tooth surface contours after rotation are registered and fused.

[0014] According to some embodiments of this application, registering the full tooth surface point cloud with the nominal tooth surface model includes: Based on the central axis parameters of the reference cylindrical segment, perform axis alignment transformation on the full tooth surface point cloud; The point cloud of the entire tooth surface is axially translated and corrected, and the region is trimmed in combination with the radius range and the effective tooth width range to obtain the effective tooth surface region for registration. Search for the rotation angle around the gear axis of the full tooth surface point cloud within the preset tooth pitch angle range to obtain the initial angular registration result; Based on the initial angular registration results, the iterative nearest point algorithm is used to perform fine registration between the full tooth surface point cloud and the nominal tooth surface model.

[0015] According to some embodiments of this application, the small module gear tooth surface deviation measurement platform further includes a multi-degree-of-freedom adjustment bracket for mounting the line laser sensor and adjusting the spatial position and angle of the line laser sensor. Before controlling the drive mechanism to drive the mounting part clamping the gear under test to rotate symmetrically, the platform further includes: Adjust the multi-degree-of-freedom adjustment bracket so that the laser projection direction of the line laser sensor forms a set angle with the extension direction of the tooth groove of the gear being tested.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the structure of the small module gear tooth surface deviation measurement platform according to an embodiment of this application; Figure 2 This is a schematic diagram of the mounting section clamping the gear under test in an embodiment of this application; Figure 3 This is an exploded view of the mounting section and the gear under test according to an embodiment of this application; Figure 4 This is a submodule of the control module and a measurement flowchart in an embodiment of this application.

[0018] Icon labels: Workbench 100; Gear position adjustment module 200, mounting part 210, reference cylindrical section 211, mandrel 212, mounting surface 213, threaded hole 214, positioning bolt 215, threaded connection section 216, positioning cylindrical section 217, head 218, drive mechanism 220, rotary drive part 221, moving drive part 222, lifting drive part 223; The gear under test is 300. Line laser sensor 400; Control module 500; Multi-degree-of-freedom adjustable bracket 600, upright frame 610, transverse cantilever 620, and composite adjustment mechanism 630. Detailed Implementation

[0019] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0020] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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 of this application.

[0021] In the description of this application, "multiple" refers to two or more. The use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or the order in which the technical features are indicated.

[0022] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0023] Reference Figures 1 to 3 As shown, an embodiment of this application describes a small module gear tooth surface deviation measurement platform, which is suitable for small module external gears with a central mounting hole, and is particularly suitable for spur gears with a module of 0.1 to 1. It includes: a worktable 100, a gear position adjustment module 200, a line laser sensor 400, and a control module 500.

[0024] Workbench 100 is used to provide a mounting and support base.

[0025] A gear position adjustment module 200 is disposed on the worktable 100, and includes a mounting part 210 and a drive mechanism 220. The mounting part 210 has a reference cylindrical section 211, which is used to clamp and fix the gear 300 under test. When the gear 300 under test is clamped in the mounting part 210, the reference cylindrical section 211 and the gear 300 under test are coaxially spaced. The drive mechanism 220 is used to drive the mounting part 210 to rotate around the axis of the reference cylindrical section 211 and to drive the mounting part 210 to move along the axial direction of the reference cylindrical section 211. The two drives can be implemented by different power elements, and the rotational and linear movements of the mounting part 210 can be performed independently. In addition, in this embodiment, the mounting part 210 is arranged horizontally, the axial direction of the reference cylindrical section 211 of the mounting part 210 is defined as the Y direction, the vertical direction is defined as the Z direction, and the horizontal direction perpendicular to the axial direction of the reference cylindrical section 211 is defined as the X direction.

[0026] The line laser sensor 400 is disposed on one side of the moving path of the mounting part 210. Its measurement field of view corresponds to the moving path of the reference cylindrical segment 211 and the gear 300 under test. When the mounting part 210 moves axially, both the reference cylindrical segment 211 and the gear 300 under test can pass through the measurement field of view of the line laser sensor 400. The line laser sensor 400 can sequentially collect the tooth surface contour point cloud of the gear 300 under test and the surface contour point cloud of the reference cylindrical segment 211 during a single movement of the mounting part 210, thereby realizing linear scanning in the Y direction.

[0027] The control module 500 is electrically or communicatively connected to the drive mechanism 220 and the line laser sensor 400, respectively. The control module 500 is configured to perform at least the following operations: control the drive mechanism 220 to drive the mounting part 210 to rotate in an indexing manner, and drive the mounting part 210 to move axially at each indexing position, so that the reference cylindrical segment 211 and the gear under test 300 both pass through the measurement field of view of the line laser sensor 400; at each indexing position, during the movement of the mounting part 210, control the line laser sensor 400 to acquire the surface contour point cloud of the reference cylindrical segment 211 and the local tooth surface contour point cloud of the gear under test 300; perform cylindrical fitting on the surface contour point cloud of the reference cylindrical segment 211 to obtain the central axis parameter of the reference cylindrical segment 211, and establish a measurement coordinate system based on the central axis parameter; based on the measurement coordinate system and the actual angle values ​​corresponding to each indexing position, perform a unified coordinate transformation on each local tooth surface contour point cloud and fuse them to obtain the full tooth surface point cloud of the gear under test 300.

[0028] It should be noted that since the reference cylindrical segment 211 is coaxial with the gear 300 being measured, the axis corresponding to the central axis parameter of the reference cylindrical segment 211 is the central axis of the gear 300 being measured, which is also the rotation reference axis of the gear 300 being measured during the actual measurement process.

[0029] At least one method of use in this embodiment is as follows: First, the gear 300 to be measured is clamped in the mounting part 210, so that the reference cylindrical section 211 and the gear 300 to be measured are coaxially spaced. Then, each module is placed in the initial reference position, and the process parameters of the measurement task are set by the control module 500. The process parameters include, but are not limited to, linear scanning speed, linear scanning stroke, sampling frequency of the line laser sensor, interval angle of indexing rotation, and number of indexing rotations, etc. After preparation, the measurement is started. The control module 500 controls the drive mechanism 220 to drive the mounting part 210 to rotate in the indexing direction, and at each indexing position, drives the mounting part 210 to move linearly in the Y direction, so that the reference cylindrical section 211 and the gear 300 to be measured both pass through the measurement field of view of the line laser sensor 400, so that the line laser sensor 400 performs linear scanning in the Y direction, and collects the surface contour point cloud of the reference cylindrical section 211 and the local tooth surface contour point cloud of the gear 300 to be measured. After all scans are completed, the control module 500 performs cylindrical fitting on the surface contour point cloud of the reference cylindrical segment 211 to obtain the central axis parameters of the reference cylindrical segment 211, and establishes a measurement coordinate system based on this. Then, based on the measurement coordinate system and the actual angle values ​​corresponding to each indexing position, the control module 500 performs a unified coordinate transformation and fusion on the local tooth surface contour point cloud to obtain the full tooth surface point cloud of the gear under test 300. Afterwards, the control module 500 can establish a nominal tooth surface model according to the nominal geometric parameters of the gear under test 300, register the full tooth surface point cloud with the nominal tooth surface model, calculate the normal deviation, and realize the deviation evaluation of the full tooth surface of the gear under test 300.

[0030] This embodiment has the following beneficial effects: Firstly, by setting reference cylindrical segments 211 on the mounting part 210 that are coaxially spaced with the gear 300 being measured, the line laser sensor 400 can simultaneously acquire the local tooth surface contour point cloud of the gear 300 being measured and the surface contour point cloud of the reference cylindrical segment 211 within the same linear scanning stroke. This allows for cylindrical fitting of the surface contour point cloud of the reference cylindrical segment 211 to obtain the central axis parameters of the actual rotation reference. Data acquisition and rotation reference establishment are completed synchronously under single clamping conditions, avoiding the reference offset error caused by offline calibration, additional targets, or ideal clamping models. Secondly, the control module 500 can establish a measurement coordinate system based on the central axis parameters, and combine the actual angle values ​​corresponding to each division position to unify the coordinates of each local tooth surface contour point cloud, so that each group of local point clouds can be mapped to the same physical rotation reference, reducing the fusion error of multi-division point clouds and improving the accuracy and repeatability of full tooth surface three-dimensional reconstruction. Third, the control module 500 can register the reconstructed full tooth surface point cloud with the nominal tooth surface model of the gear under test 300 and calculate the normal deviation, outputting the tooth profile deviation, tooth direction / helix deviation and tooth pitch deviation of the left and right tooth surfaces of all gear teeth, realizing the digital deviation assessment of the entire circumference and teeth of small module gears.

[0031] It should be noted that the above-mentioned "simultaneously acquiring the local tooth surface contour point cloud of the gear under test 300 and the surface contour point cloud of the reference cylindrical segment 211" means that when the line laser sensor 400 completes one linear scanning stroke at a single indexing position, the multi-frame contour data it continuously outputs includes both the contour data of the tooth surface region and the contour data of the reference cylindrical segment 211 region, without requiring the tooth surface region and the reference cylindrical segment region to appear simultaneously in the same frame contour.

[0032] Reference Figure 2 and Figure 3 As shown, in some embodiments of this application, the mounting portion 210 includes a mandrel 212 and a positioning bolt 215. The mandrel 212 has a mounting surface 213 at one end away from the drive mechanism 220. The mounting surface 213 is perpendicular to the axis of the reference cylindrical segment 211. The mounting surface 213 has threaded holes 214 coaxially distributed with the reference cylindrical segment 211, which is disposed on the mandrel 212.

[0033] The positioning bolt 215 is used to pass through the central mounting hole of the gear under test 300 and lock it to the mandrel 212. Specifically, it includes a threaded connecting section 216, a positioning cylindrical section 217 and a head 218 connected axially in sequence. The threaded connecting section 216 is threaded to the threaded hole 214. The positioning cylindrical section 217 matches the diameter of the central mounting hole of the gear under test 300 and passes through the central mounting hole of the gear under test 300 to radially support and position the gear under test 300. The head 218 abuts against the end face of the gear under test 300 to press the gear under test 300 against the mounting surface 213.

[0034] Through the above structural design, the gear 300 to be tested can be conveniently and reliably clamped on the mounting part 210, and positioning, locking and benchmark establishment can be achieved simultaneously in a single clamping. In addition, by replacing the positioning bolts 215 of different specifications, it can be compatible with gears 300 with different hole diameters, thereby improving the versatility of the platform.

[0035] Reference Figure 1 As shown, in some embodiments of this application, the drive mechanism 220 includes a rotation drive unit 221 and a movement drive unit 222.

[0036] The rotary drive unit 221 is connected to the mandrel 212 of the mounting unit 210 to drive the mounting unit 210 to rotate around the axis of the reference cylindrical section 211, thereby causing the mounting unit 210 and the gear 300 under test to rotate synchronously. The rotary drive unit 221 can be a precision rotary table, and the mandrel 212 of the mounting unit 210 is mounted on the output end of the precision rotary table.

[0037] The rotary drive unit 221 is equipped with an angle encoder, which is communicatively connected to the control module 500. When the rotary drive unit 221 drives the mounting unit 210 to rotate in increments, the actual angle value at each increment position can be accurately obtained through the angle encoder and fed back to the control module 500. The control module 500 realizes closed-loop control based on the feedback from the angle encoder.

[0038] The moving drive unit 222 is connected to the rotating drive unit 221. The moving drive unit 222 is used to drive the rotating drive unit 221 to move axially along the reference cylindrical section 211, so that the rotating drive unit 221, the mounting part 210 and the gear under test 300 move synchronously. The moving drive unit 222 can adopt high-precision drive components such as linear motors and ball screw mechanisms.

[0039] The mobile drive unit 222 is equipped with a displacement encoder, which is communicatively connected to the control module 500. When the mobile drive unit 222 drives the rotary drive unit 221, the mounting unit 210 and the gear under test 300 to move as a whole, the actual displacement can be accurately obtained through the displacement encoder and fed back to the control module 500. The control module 500 realizes closed-loop control based on the feedback of the displacement encoder.

[0040] By adopting the above settings, this embodiment can achieve precise control of the movement of the gear 300 under test, thereby improving the accuracy of deviation measurement.

[0041] Furthermore, the control module 500 can convert the pulse signal of the displacement encoder into an external trigger signal according to a preset pulse equivalent and output it to the line laser sensor 400 to trigger the line laser sensor 400 to perform equidistant sampling, ensuring that the sampling point spacing is strictly synchronized with the actual displacement of the gear 300 under test, thereby reducing the impact of motion speed fluctuations, control delays and acceleration / deceleration processes on the uniformity of sampling point distribution, and providing a more stable original data foundation for subsequent point cloud reconstruction.

[0042] Reference Figure 1 As shown, in some embodiments of this application, the drive mechanism 220 further includes a lifting drive unit 223, which is used to drive the rotary drive unit 221, the mounting part 210, and the gear under test 300 to lift as a whole, thereby adjusting the height of the gear under test 300 and the mounting part 210 to a better height so that the line laser sensor 400 can sample. The lifting drive unit 223 may be a lifting platform.

[0043] In some specific embodiments, such as Figure 1 As shown, the lifting drive unit 223 is disposed between the moving drive unit 222 and the rotating drive unit 221. A storage plate is disposed at the output end of the moving platform, and the lifting drive unit 223 is fixed on the storage plate. The rotating drive unit 221 is connected to the output end of the lifting drive unit 223. In some other embodiments, the lifting drive unit 223 may also be disposed at the level above the moving drive unit 222, that is, the moving drive unit 222 is connected to the output end of the lifting drive unit 223, and the rotating drive unit 221 is connected to the output end of the moving drive unit 222. The specific location of the lifting drive unit 223 can be selected according to the actual situation, and this application does not make a specific limitation on it.

[0044] In this embodiment, the rotation drive unit 221, the movement drive unit 222, and the lifting drive unit 223 are all electrically or communicatively connected to the control module 500.

[0045] Reference Figure 1 As shown, in some embodiments of this application, the small module gear tooth surface deviation measurement platform further includes a multi-degree-of-freedom adjustment bracket 600. The multi-degree-of-freedom adjustment bracket 600 is disposed on the worktable 100 and is used to install the line laser sensor 400 and adjust the spatial position and angle of the line laser sensor 400, so that the line laser sensor 400 is in a better sampling position and the point cloud acquisition integrity is improved.

[0046] In some specific embodiments, the preferred sampling position described above satisfies the following conditions: First, during the movement of the mounting part 210 and the gear under test 300 within the travel stroke, the laser line of the line laser sensor 400 can cover the area of ​​the tooth surface to be measured of the gear under test 300 and the reference cylindrical section 211 on the mandrel 212; Second, the working distance of the line laser sensor 400 is within the optimal measurement range; Third, the laser projection direction of the line laser sensor 400 forms a set angle with the tooth groove extension direction of the gear under test 300 to reduce obstruction and reflection dead angles.

[0047] In some specific embodiments, such as Figure 1 As shown, the multi-degree-of-freedom adjustable support 600 includes: a vertical frame 610, a horizontal cantilever 620, and a composite adjustment mechanism 630. The vertical frame 610 is adjustablely mounted on the worktable 100 along the Y direction. The horizontal cantilever 620 is adjustablely mounted on the upper end of the vertical frame 610 and distributed along the X direction. The composite adjustment mechanism 630 includes a movable base and a rotating frame. The movable base is adjustablely mounted on the horizontal cantilever 620 along the X direction. The rotating frame is rotatably connected to the movable base around a first axis. The line laser sensor 400 is rotatably connected to the rotating frame around a second axis. The first axis is parallel to the Y direction, and the second axis is perpendicular to the first axis. It should be noted that the adjustment of the above components can be achieved electrically (through a motor) and controlled uniformly by the control module 500; of course, manual adjustment can also be used, and locking can be achieved through a manual locking knob. Corresponding displacement or angle scales are provided for position indication.

[0048] Reference Figure 4 As shown, in some embodiments of this application, the control module 500 may include an acquisition submodule, a calibration submodule, a reconstruction submodule, and a deviation measurement submodule.

[0049] The acquisition submodule generates preset scanning pose parameters before linear scanning, controls the multi-degree-of-freedom adjustment bracket 600 (electrically adjustable) to adjust the line laser sensor 400 to the preset scanning pose, and controls the movement drive unit 222 to drive the mounting unit 210 and the gear under test 300 to move along the Y direction, while simultaneously controlling the line laser sensor 400 to perform linear scanning. During the sampling process of the line laser sensor 400, the acquisition submodule converts the pulse signal of the displacement encoder into an external trigger signal according to a preset pulse equivalent, thereby triggering the line laser sensor 400 to perform equidistant sampling, and obtaining contour data including the local tooth surface contour point cloud of the gear under test 300 and the surface contour point cloud of the reference cylindrical segment 211 within the same scanning stroke.

[0050] The calibration submodule is used to segment the local tooth surface contour point cloud of the gear under test 300 and the surface contour point cloud of the reference cylindrical segment 211. Based on the surface contour point cloud of the reference cylindrical segment 211 in the contour data, it performs cylindrical fitting to obtain the central axis parameters of the reference cylindrical segment 211, so as to obtain the central axis of the reference cylindrical segment 211. The central axis is the rotation reference axis of the gear under test 300. Based on this, a measurement coordinate system and coordinate transformation relationship for point cloud conversion are established.

[0051] The reconstruction submodule is used to combine the actual angle values ​​fed back by the angle encoder, transform the point cloud of each local tooth surface contour to a unified coordinate system, perform registration and fusion, and output the full tooth surface point cloud of the tested gear 300.

[0052] The deviation measurement submodule is used to generate a nominal tooth surface model based on the nominal geometric parameters of the gear 300 under test, register the full tooth surface point cloud with the nominal tooth surface model, calculate the normal deviation, and output the tooth profile deviation, helix deviation and pitch deviation, etc., which meet the set requirements, such as the requirements in GB / T 10095.1—2022.

[0053] This application also proposes a method for measuring the tooth surface deviation of small module gears, applied to the small module gear tooth surface deviation measurement platform of the above embodiments, which includes the following steps: The control module 500 controls the drive mechanism 220 to drive the mounting part 210, which clamps the gear 300 to be measured, to rotate in an indexing angle according to a set indexing angle. At each indexing position, the control module 500 controls the drive mechanism 220 to drive the mounting part 210 to move along the axial direction (Y direction) of the reference cylindrical section 211, and controls the line laser sensor 400 to collect the surface contour point cloud of the reference cylindrical section 211 and the local tooth surface contour point cloud of the gear 300 to be measured.

[0054] The control module 500 performs cylindrical fitting on the surface contour point cloud of the reference cylindrical segment 211 at at least one indexing position to obtain the central axis parameters of the reference cylindrical segment 211, and establishes a measurement coordinate system based on the central axis parameters. Since the reference cylindrical segment 211 is coaxial with the rotation axis of the rotary drive unit 221, the fitted central axis can be considered as the spatial expression of the physical rotation axis of the rotary drive unit 221 in the coordinate system of the line laser sensor 400. Based on this, a measurement coordinate system is established, defining the aforementioned central axis as the principal axis of rotation of the measurement coordinate system, and a right-handed coordinate system is established by combining the scanning direction and its normal direction. Through this step, the coordinate transformation relationship between the original sampling coordinate system of the line laser sensor 400 and the measurement coordinate system of the gear under test 300 can be obtained.

[0055] Based on the measurement coordinate system and the actual angle values ​​corresponding to each indexing position, the control module 500 performs a unified coordinate transformation and fusion on the point cloud of each local tooth surface contour to obtain the full tooth surface point cloud of the gear under test 300.

[0056] The control module 500 establishes a nominal tooth surface model of the gear 300 based on the nominal geometric parameters of the gear 300 under test, registers the full tooth surface point cloud with the nominal tooth surface model, and then calculates the normal deviation of the full tooth surface point cloud relative to the nominal tooth surface model; where the normal deviation refers to the difference in the normal direction distance from the measured tooth surface point to the corresponding nominal tooth surface position.

[0057] The method for measuring the tooth surface deviation of small-module gears in this embodiment utilizes a line laser sensor 400 to simultaneously acquire the local tooth surface contour point cloud of the gear under test 300 and the surface contour point cloud of the reference cylindrical segment 211 within the same linear scanning stroke. The surface contour point cloud of the reference cylindrical segment 211 is then subjected to cylindrical fitting to obtain the central axis parameters of the actual rotational reference. This allows for simultaneous data acquisition and rotational reference establishment under single-clamping conditions, avoiding reference offset errors caused by offline calibration, additional targets, or ideal clamping models. The method establishes the measurement based on the central axis parameters... The coordinate system is measured, and the coordinates of each local tooth surface contour point cloud are unified by combining the actual angle values ​​corresponding to each division position. This allows each group of local point clouds to be mapped to the same physical rotation reference, reducing the fusion error of multi-division point clouds and improving the accuracy and repeatability of the full tooth surface 3D reconstruction. By registering the reconstructed full tooth surface point cloud with the nominal tooth surface model of the gear 300 under test and calculating the normal deviation, the tooth profile deviation, tooth direction / helix deviation and tooth pitch deviation of the left and right tooth surfaces of all gear teeth can be output, realizing the digital deviation assessment of the entire circumference and teeth of small module gears.

[0058] In some embodiments of this application, the control module 500 controls the line laser sensor 400 to acquire the surface contour point cloud of the reference cylindrical segment 211 and the local tooth surface contour point cloud of the gear under test 300. This includes: the control module 500, based on the displacement feedback signal from the displacement encoder, controls the line laser sensor 400 to acquire the surface contour point cloud of the reference cylindrical segment 211 and the local tooth surface contour point cloud of the gear under test 300 at equal intervals. Specifically, the control module 500 converts the pulse signal of the displacement encoder into an external trigger signal according to a preset pulse equivalent, triggering the line laser sensor 400 to perform equal-interval sampling. This ensures that the sampling point spacing is strictly synchronized with the actual displacement of the gear under test 300, thereby reducing the impact of motion speed fluctuations, control delays, and acceleration / deceleration processes on the uniformity of the sampling point distribution, and providing a more stable original data foundation for subsequent point cloud reconstruction.

[0059] In some embodiments of this application, the control module 500 performs cylindrical fitting on the surface profile point cloud at at least one indexing position to obtain the central axis parameters of the reference cylindrical segment 211, including: performing cylindrical fitting on the surface profile point cloud at the initial indexing position to obtain the central axis parameters of the reference cylindrical segment 211, and the central axis parameters of the reference cylindrical segment 211 obtained at the initial indexing position are used as the final central axis parameters of the reference cylindrical segment 211.

[0060] Alternatively, in some other embodiments of this application, the control module 500 performs cylindrical fitting on the surface contour point cloud at at least one indexing position to obtain the central axis parameters of the reference cylindrical segment 211. This includes: first performing cylindrical fitting on the surface contour point cloud at multiple indexing positions to obtain the central axis parameters of the reference cylindrical segment 211 at multiple indexing positions, and then performing averaging or least squares processing to obtain the final central axis parameters of the reference cylindrical segment 211. By averaging or least squares processing, more stable central axis parameters can be obtained.

[0061] In some embodiments of this application, the control module 500 performs a unified coordinate transformation and fusion of the local tooth surface contour point clouds based on the measurement coordinate system and the actual angle values ​​corresponding to each indexing position. This includes: First, the control module 500 transforms the local tooth surface contour point clouds at each indexing position to a unified measurement coordinate system; then, the control module 500 rotates the transformed local tooth surface contour point clouds around the axis corresponding to the central axis parameter to a unified reference angle position according to the actual angle values ​​corresponding to each indexing position, so that the local tooth surface contour point clouds collected at each indexing position can be mapped to the same global coordinate system; then, the control module 500 registers and fuses the rotated local tooth surface contour point clouds; after fusion, a three-dimensional point cloud morphology covering all tooth surfaces of the gear 300 under test can be obtained.

[0062] In some embodiments of this application, the above-mentioned registration of the full tooth surface point cloud with the nominal tooth surface model includes: First, the control module 500 performs an axis alignment transformation on the full tooth surface point cloud (i.e., the measured point cloud) based on the fitted central axis parameters of the reference cylindrical segment 211, so that the gear axis of the full tooth surface point cloud is aligned with the axis of the nominal tooth surface model; then, the control module 500 performs axial translation correction on the full tooth surface point cloud, and performs region clipping in combination with the radius range and the effective tooth width range to obtain an effective tooth surface region for registration; then, the control module 500 searches for the rotation angle around the gear axis of the full tooth surface point cloud within a preset tooth pitch angle range to obtain an initial angular registration result; finally, based on the initial angular registration result, the control module 500 uses an iterative nearest point algorithm to perform fine registration of the full tooth surface point cloud and the nominal tooth surface model.

[0063] Furthermore, a two-stage iterative closest point algorithm can be used for fine registration. The first stage uses the point-to-point ICP algorithm (Iterative Closest Point) for fine-tuning, and the second stage performs further refinement at a smaller corresponding distance threshold to further reduce residual pose error.

[0064] In some embodiments of this application, before the control module 500 controls the drive mechanism 220 to drive the mounting part 210, which clamps the gear 300 to be measured, to rotate by indexing, the step of adjusting the multi-degree-of-freedom adjustment bracket 600 is further included: so that the laser projection direction of the line laser sensor 400 forms a set angle with the extension direction of the tooth groove of the gear 300 to reduce the blind spot and reflection dead angle.

[0065] The following reference Figures 1 to 4 A method for measuring the tooth surface deviation of a small module gear according to one specific embodiment of this application is described, which includes the following steps: Step 1: Preparation before measurement Before measuring the deviation of the entire gear tooth surface, the platform preparation and basic parameter settings should be completed according to the basic parameters of the gear 300 to be measured. The basic parameters include, but are not limited to: gear module, number of teeth, pressure angle, helix angle, tooth width, inner diameter, outer diameter range, and the accuracy items to be measured.

[0066] Then check the installation status of the gear posture adjustment module 200, the multi-degree-of-freedom adjustment bracket 600, and the line laser sensor 400 to confirm that each component is in a stable connection state. Subsequently, perform a zero-return operation on the drive mechanism 220 to bring the moving drive unit 222, the rotating drive unit 221, and the lifting drive unit 223 to their initial reference positions.

[0067] Next, the nominal geometric parameters of the gear 300 under test are input or imported into the control module 500, and the process parameters for this measurement task are set. These process parameters include, but are not limited to: linear scanning speed, linear scanning stroke, sampling frequency of the line laser sensor or equivalent external trigger pulse, indexing angle of the indexing rotation, number of indexing acquisitions, target working distance of the line laser sensor, and point cloud filtering and fitting calculation parameters. The indexing angle of the indexing rotation must be set according to the number of gear teeth, tooth surface coverage requirements, and measurement efficiency. For measurement tasks requiring coverage of the entire tooth surface, a step-by-step indexing scan at a fixed angle must be used.

[0068] Step 2: Clamping the gear under test and adjusting the pose of the line laser sensor Based on the size of the center mounting hole of the gear 300 being tested, select a positioning bolt 215 of the appropriate size to reliably lock the gear 300 being tested onto the mandrel 212 (the mandrel 212 is normally fixed to the output end of the rotary drive unit 221).

[0069] After clamping, the rotating drive unit 221 can be rotated at low speed to initially observe whether the rotation of the gear 300 being tested is stable, in order to determine whether there is obvious wobble or looseness in the clamping. If necessary, the gear can be re-clamped or the appropriate positioning bolt 215 can be replaced to improve the coaxiality and stability of the clamping.

[0070] Subsequently, the position and orientation of the line laser sensor 400 are adjusted by adjusting the multi-degree-of-freedom adjustment bracket 600. This ensures that the line laser sensor 400 meets the following requirements: First, during the movement of the mounting part 210 and the gear under test 300 within their travel stroke, the laser line of the line laser sensor 400 can cover the area of ​​the tooth surface to be measured on the gear under test 300 and the reference cylindrical section 211 on the mandrel 212; second, the working distance of the line laser sensor 400 is within the optimal measurement range; third, the laser projection direction of the line laser sensor 400 forms a set angle with the tooth groove extension direction of the gear under test 300 to reduce obstruction and reflection dead angles.

[0071] Step 3: Contour acquisition at a single indexing position After clamping and sensor adjustment are completed, the control module 500 controls the rotary drive unit 221 to stay at the initial indexing position, and then controls the mobile drive unit 222 to drive the gear under test 300 to perform linear scanning along the Y direction.

[0072] During the scanning process, the displacement encoder continuously outputs pulse signals. The control module 500 converts the encoder pulses into external trigger signals for the line laser sensor 400 according to the preset pulse equivalent. Whenever the cumulative displacement reaches the set equal-interval sampling condition, an external trigger pulse is output, thereby triggering the line laser sensor 400 to collect the contour data of the current section. After collecting the data, the control module 500 receives and buffers all contour data within the Y-direction scanning stroke at the indexing position, providing the original data basis for subsequent coordinate transformation and point cloud reconstruction.

[0073] Step 4: Full-circle scanning at multiple division positions After completing the scanning acquisition at one indexing position, the control module 500 rotates intermittently according to the preset indexing angle. Step three above is repeated at each indexing position until the preset number of indexing rotations are completed. For full-circumference measurement, all indexing positions should cover the entire circumference of the gear 300 being measured. A complete set of scan contour data is obtained at each indexing position, which includes both the local tooth surface contour point cloud and the reference cylindrical segment 211 point cloud. Simultaneously, the angle encoder records and outputs the actual angle values ​​corresponding to each indexing position for subsequent coordinate unification and point cloud reconstruction.

[0074] Step 5: Fitting the reference cylindrical segment and establishing the measurement coordinate system The control module 500 performs cylindrical fitting on the surface contour point cloud of the reference cylindrical segment 211 obtained in step four to obtain the central axis parameters of the reference cylindrical segment 211. Specifically, the control module 500 can directly perform cylindrical fitting on the surface contour point cloud of the reference cylindrical segment 211 at the initial indexing position to obtain the central axis parameters of the reference cylindrical segment 211, or it can first perform cylindrical fitting on the surface contour point cloud at multiple indexing positions to obtain the central axis parameters of the reference cylindrical segment 211 at multiple indexing positions, and then perform averaging or least squares processing.

[0075] After fitting, a measurement coordinate system for the gear 300 under test is established. The fitted central axis is defined as the principal axis of rotation of the measurement coordinate system, and a right-handed coordinate system is established by combining the scanning direction and its normal direction. Through this step, the coordinate transformation relationship between the original sampling coordinate system of the sensor and the measurement coordinate system can be obtained.

[0076] Step Six: Local Point Cloud Unification and Full Tooth Surface 3D Reconstruction First, the control module 500 converts the local tooth surface contour point cloud at each indexing position into a unified measurement coordinate system.

[0077] Then, the control module 500 rotates the converted local tooth surface contour point cloud around the axis corresponding to the central axis parameter to a unified reference angle position according to the actual angle value corresponding to each indexing position, so that the local tooth surface contour point cloud collected at each indexing position can be mapped to the same global coordinate system.

[0078] After completing the coordinate unification, the control module 500 registers and fuses the point clouds of each local tooth surface contour. During registration, the rigid body transformation method based on the angle encoder angle feedback and the reference axis parameters is used for initial alignment. When it is necessary to further improve the reconstruction accuracy, a local optimization registration algorithm can be added on the basis of the initial alignment to reduce the residual error in the local overlapping area.

[0079] After fusion, a three-dimensional point cloud morphology covering all 300 tooth surfaces of the tested gear is obtained. If necessary, outlier removal, noise filtering, sparse region interpolation, or normal reestimation can be performed on the reconstructed full-tooth-surface point cloud to improve the stability of subsequent deviation calculations.

[0080] Step 7: Establishing the nominal tooth surface model and registering the point cloud First, a nominal tooth surface model is established based on the nominal geometric parameters of the gear 300 being measured. These parameters include design parameters such as module, number of teeth, pressure angle, helix angle, addendum coefficient, displacement coefficient, and tooth width. The nominal tooth surface model can be generated using analytical geometry, parametric tooth surface modeling, or by importing a CAD theoretical model. This nominal tooth surface model is established within a theoretical coordinate framework consistent with the aforementioned measurement coordinate system.

[0081] Subsequently, the reconstructed full-tooth surface point cloud is registered with the nominal tooth surface model. The registration process is as follows: Based on the central axis parameters of the reference cylindrical segment 211, the control module 500 performs an axis alignment transformation on the full-tooth surface point cloud to align the axis of the full-tooth surface point cloud (i.e., the measured point cloud) with the axis of the nominal tooth surface model. Then, the control module 500 performs axial translation correction on the full-tooth surface point cloud and performs region clipping based on the radius range and effective tooth width range to obtain an effective tooth surface region for registration. Next, the control module 500 searches for the rotation angle around the gear axis of the full-tooth surface point cloud within a preset tooth pitch angle range to obtain the initial angular registration result. Finally, based on the initial angular registration result, the control module 500 uses a two-stage iterative closest point algorithm to perform fine registration of the full-tooth surface point cloud and the nominal tooth surface model. The first stage uses a point-to-point ICP algorithm (Iterative Closest Point) for fine-tuning, and the second stage performs further refinement at a smaller corresponding distance threshold.

[0082] Step 8: Deviation Calculation and Result Output After the nominal tooth surface model and the full tooth surface point cloud are registered, the control module 500 calculates the normal deviation of the measured point cloud (i.e., the full tooth surface point cloud) relative to the nominal tooth surface model. The deviation calculation may include the following steps: A. Tooth surface partitioning Based on the nominal number of teeth and the theoretical tooth pitch angle, the measured point cloud is divided into tooth segments along the circumferential angle. Then, based on the positional relationship of the points relative to the center angle of the corresponding tooth, each tooth point cloud is divided into a left tooth surface point cloud and a right tooth surface point cloud. Furthermore, outliers can be removed by combining the distance threshold between the measured points and the nominal tooth surface point cloud.

[0083] B. Tooth deviation extraction A set of measured tooth direction points is extracted near a predetermined reference cylindrical surface, and the reference cylindrical surface is unfolded into a two-dimensional plane. A theoretical helix is ​​generated based on the nominal geometric parameters of the gear, and normals are established at multiple axial sampling points on the theoretical helix. The intersection points between each normal and the broken line formed by the measured tooth direction point set are calculated, and the signed distance of each intersection point relative to the corresponding theoretical sampling point along the normal direction is calculated to obtain the tooth direction deviation curve. The total deviation of the helix, the tilt deviation of the helix, and the shape deviation of the helix are calculated based on the deviation curve.

[0084] C. Tooth profile deviation extraction Extract the set of measured tooth profile cross-section points at a predetermined cross-section position in the tooth width direction; generate a theoretical involute evaluation curve based on the nominal geometric parameters of the gear, and establish normals at multiple sampling points; calculate the intersection points between each normal and the broken line formed by the measured tooth profile point set, calculate the signed distance along the normal direction, and obtain the tooth profile deviation curve; calculate the total tooth profile deviation, tooth profile inclination deviation, and tooth profile shape deviation based on the deviation curve.

[0085] D. Tooth pitch deviation extraction Determine the tooth pitch evaluation position or representative point of each tooth's left and right tooth surfaces near the predetermined measurement circle. Calculate the actual tooth pitch based on the central angle between the evaluation positions on the same side of adjacent teeth, and compare it with the theoretical tooth pitch to obtain the individual tooth pitch deviation. Further, calculate the cumulative tooth pitch deviation based on the cumulative value of multiple individual tooth pitch deviations.

[0086] E. Standard Evaluation The evaluation range, sampling location, and evaluation rules for the aforementioned tooth direction deviation, tooth profile deviation, and tooth pitch deviation shall preferably be implemented in accordance with GB / T 10095.1—2022.

[0087] Finally, the control module 500 outputs the measurement results, which may include graphical results, numerical results, and structured data results.

[0088] The graphical results include at least: a point cloud model of the entire tooth surface of the gear under test, the registration results of the nominal tooth surface model and the point cloud of the entire tooth surface, a color cloud map of the normal deviation of the entire tooth surface, the tooth profile deviation curves of the left and right tooth surfaces of each tooth, the helical deviation curves, and the tooth pitch deviation diagram.

[0089] The numerical results include at least: the total deviation of the tooth profile, the tooth profile inclination deviation, the tooth profile shape deviation, the total deviation of the helix, the helix inclination deviation, the helix shape deviation, as well as the individual tooth pitch deviation and the cumulative tooth pitch deviation; further, it also includes the maximum value, minimum value, average value, standard deviation and out-of-tolerance statistics of the above deviation items.

[0090] The structured data results should include at least: the fitting parameters of the rotation reference axis, the actual angle values ​​at each division position, the point cloud fusion residuals, the number of effective sampling points, the number of discarded points, the evaluation area effectiveness rate, and the parameter record file corresponding to the measurement task.

[0091] Furthermore, the system can automatically output the accuracy grade judgment result and the pass / fail judgment result of the tested gear according to the preset tolerance zone or standard limit, and generate a report file that meets the testing requirements.

[0092] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine different embodiments or examples described in this specification.

[0093] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A small module gear tooth surface deviation measurement platform, characterized in that, include: A gear position adjustment module includes a mounting part and a drive mechanism. The mounting part has a reference cylindrical section and is used to clamp and fix the gear under test, and to make the reference cylindrical section and the gear under test coaxially spaced apart. The drive mechanism is used to drive the mounting part to rotate around the axis of the reference cylindrical section and to move along the axial direction of the reference cylindrical section. A line laser sensor is disposed on one side of the moving path of the mounting part; The control module is configured to perform the following operations: The drive mechanism is controlled to drive the mounting part to rotate in degree, and at each degree position, the mounting part is driven to move axially, so that the reference cylindrical section and the gear under test both pass through the measurement field of view of the line laser sensor. During the movement of the mounting part, the line laser sensor is controlled to acquire the surface contour point cloud of the reference cylindrical section and the local tooth surface contour point cloud of the gear under test. Cylindrical fitting is performed on the surface contour point cloud to obtain the central axis parameters of the reference cylindrical segment, and a measurement coordinate system is established based on the central axis parameters; Based on the measurement coordinate system and the actual angle values ​​corresponding to each of the indexing positions, the point clouds of each local tooth surface contour are subjected to a unified coordinate transformation and fused to obtain the full tooth surface point cloud of the gear under test.

2. The small module gear tooth surface deviation measurement platform according to claim 1, characterized in that, The mounting unit includes: A mandrel, wherein a mounting surface is provided at one end of the mandrel away from the driving mechanism, the mounting surface having threaded holes coaxially distributed with the reference cylindrical segment, the reference cylindrical segment being disposed on the mandrel; The positioning bolt includes a threaded connecting section, a positioning cylindrical section, and a head connected axially in sequence. The threaded connecting section is threaded into the threaded hole. The positioning cylindrical section passes through the central mounting hole of the gear under test to radially support and position the gear under test. The head abuts against the end face of the gear under test to press the gear under test against the mounting surface.

3. The small module gear tooth surface deviation measurement platform according to claim 1, characterized in that, The drive mechanism includes: A rotary drive unit is connected to the mounting unit for driving the mounting unit to rotate around the axis of the reference cylindrical segment. The rotary drive unit is equipped with an angle encoder. A mobile drive unit is connected to the rotary drive unit and is used to drive the rotary drive unit to move axially along the reference cylindrical segment. The mobile drive unit is equipped with a displacement encoder.

4. The small module gear tooth surface deviation measurement platform according to claim 1, characterized in that, The small module gear tooth surface deviation measurement platform also includes a multi-degree-of-freedom adjustment bracket for mounting the line laser sensor and adjusting the spatial position and angle of the line laser sensor.

5. A method for measuring the tooth surface deviation of small module gears, applied to the small module gear tooth surface deviation measurement platform described in claim 1, characterized in that, Includes the following steps: The drive mechanism is controlled to drive the mounting part, which clamps the gear under test, to rotate axially. At each indexed position, the drive mechanism is controlled to drive the mounting part to move axially. The line laser sensor is also controlled to collect the surface profile point cloud of the reference cylindrical section and the local tooth surface profile point cloud of the gear under test. Cylindrical fitting is performed on the surface profile point cloud at at least one of the said indexing positions to obtain the central axis parameters of the reference cylindrical segment, and a measurement coordinate system is established based on the central axis parameters; Based on the measurement coordinate system and the actual angle values ​​corresponding to each of the indexing positions, the point clouds of each of the local tooth surface contours are subjected to a unified coordinate transformation and fused to obtain the full tooth surface point cloud of the gear under test. Based on the nominal geometric parameters of the gear under test, a nominal tooth surface model of the gear under test is established. The point cloud of the full tooth surface is registered with the nominal tooth surface model, and then the normal deviation of the point cloud of the full tooth surface relative to the nominal tooth surface model is calculated.

6. The method for measuring the tooth surface deviation of small module gears according to claim 5, characterized in that, The drive mechanism is equipped with a displacement encoder. Controlling the line laser sensor to acquire the surface contour point cloud of the reference cylindrical segment and the local tooth surface contour point cloud of the gear under test includes: Based on the displacement feedback signal from the displacement encoder, the line laser sensor is controlled to collect the surface contour point cloud of the reference cylindrical segment and the local tooth surface contour point cloud of the gear under test at equal intervals.

7. The method for measuring the tooth surface deviation of small module gears according to claim 5, characterized in that, The step of performing cylindrical fitting on the surface profile point cloud at at least one of the indexing positions to obtain the central axis parameters of the reference cylindrical segment includes: Cylindrical fitting is performed on the surface profile point cloud at the initial indexing position to obtain the central axis parameters of the reference cylindrical segment; Alternatively, cylindrical fitting can be performed on the surface contour point clouds at multiple indexing positions to obtain the central axis parameters of the reference cylindrical segment at multiple indexing positions, and then averaging or least squares processing can be performed to obtain the final central axis parameters of the reference cylindrical segment.

8. The method for measuring the tooth surface deviation of small module gears according to claim 5, characterized in that, The process of performing a unified coordinate transformation and fusing the point clouds of each local tooth surface contour based on the measurement coordinate system and the actual angle values ​​corresponding to each of the graduation positions includes: Transform the local tooth surface contour point cloud at each of the specified indexing positions to the measurement coordinate system; Based on the actual angle value corresponding to each of the indexing positions, the converted local tooth surface contour point cloud is rotated around the axis corresponding to the central axis parameter to a unified reference angle position. The point clouds of the local tooth surface contours after rotation are registered and fused.

9. The method for measuring the tooth surface deviation of small module gears according to claim 5, characterized in that, The registration of the full tooth surface point cloud with the nominal tooth surface model includes: Based on the central axis parameters of the reference cylindrical segment, perform axis alignment transformation on the full tooth surface point cloud; The point cloud of the entire tooth surface is axially translated and corrected, and the region is trimmed in combination with the radius range and the effective tooth width range to obtain the effective tooth surface region for registration. Search for the rotation angle around the gear axis of the full tooth surface point cloud within the preset tooth pitch angle range to obtain the initial angular registration result; Based on the initial angular registration results, the iterative nearest point algorithm is used to perform fine registration between the full tooth surface point cloud and the nominal tooth surface model.

10. The method for measuring the tooth surface deviation of small module gears according to claim 5, characterized in that, The small module gear tooth surface deviation measurement platform also includes a multi-degree-of-freedom adjustment bracket for mounting the line laser sensor and adjusting the spatial position and angle of the line laser sensor. Before the control mechanism drives the mounting part with the gear being measured to rotate, it also includes: Adjust the multi-degree-of-freedom adjustment bracket so that the laser projection direction of the line laser sensor forms a set angle with the extension direction of the tooth groove of the gear being tested.

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