Scanning fixture, scanning method, and 3D scanner

Abstract

This reduces the effort and cost involved in scanning workpieces using optical 3D scanners. [Solution] The scanning jig is used when scanning a workpiece with an optical 3D scanner, wherein the workpiece has a first region where reflected light is appropriately received by the 3D scanner and a second region where the reflected light is not appropriately received by the 3D scanner, and the scanning jig has a reflective surface that masks the second region and allows the reflected light to be appropriately received by the 3D scanner.

Description

Technical Field

[0001] The present invention relates to a scanning jig, a scanning method, and a 3D scanner.

Background Art

[0002] When scanning a workpiece with an optical 3D scanner, depending on the reflectivity of the surface of the workpiece, the light of the 3D scanner may not be properly reflected, resulting in a decrease in the accuracy of the scan. In Patent Document 1, fine powder is applied to the surface of the workpiece to make the surface reflectivity suitable for scanning.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When using fine powder, it takes time and cost to process the fine powder after scanning. <​​​​​​​​​​​​​​​​​

[0006] According to one aspect of the present invention, the effort and cost involved in scanning a workpiece using an optical 3D scanner can be reduced. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a diagram illustrating the differential mechanism. [Figure 2] Figure 2 is a diagram illustrating a 3D scanner. [Figure 3] Figure 3 is a diagram illustrating the scanning jig. [Figure 4] Figure 4 is a diagram illustrating the scanning jig. [Figure 5] Figure 5 is a diagram illustrating a scanning jig related to Modification 1. [Figure 6] Figure 6 is a diagram illustrating a scanning jig related to Modification 1. [Figure 7] Figure 7 illustrates a scanning jig related to modified example 2. [Figure 8] Figure 8 is a diagram illustrating a scanning jig related to modified example 2. [Figure 9] Figure 9 is a diagram illustrating a scanning jig related to Modification 3. [Figure 10] Figure 10 is a diagram illustrating a scanning jig related to Modification 3. [Figure 11] Figure 11 is a diagram illustrating a scanning jig related to modified example 4. [Figure 12] Figure 12 is a diagram illustrating a scanning jig related to modified example 4. [Figure 13] Figure 13 is a diagram illustrating a scanning jig related to Modification 5. [Figure 14] Figure 14 is a diagram illustrating a scanning jig related to modified example 5.

[0008] The embodiments will be described below. In these embodiments, the differential mechanism 3 provided in the vehicle 1 will be used as an example of the workpiece to be scanned. FIG. 1 is a diagram for explaining the differential mechanism 3. FIG. 2 is a diagram for explaining the 3D scanner 4. FIG. 2 shows a state in which the work W is set on the 3D scanner 4. Note that FIG. 2 shows a schematic cross-sectional view along the rotation axis X1. In the drawings, the "vertical direction" means the vertical line direction when the work W is mounted on the 3D scanner 4. Therefore, when expressed as "upper side", it means the "upper side" in the vertical line direction, and when expressed as "lower side", it means the "lower side" in the vertical line direction.

[0009] As shown in FIG. 1, in the vehicle 1, the rotational driving force of a drive source (for example, a motor, an engine, etc.) not shown is transmitted to the differential mechanism 3 after being shifted by the intermediate gear 2. The rotation input to the differential mechanism 3 is output to the left and right drive wheels (not shown) via the drive shafts DA and DB.

[0010] The intermediate gear 2 has two gear portions (large-diameter gear portion 21 and small-diameter gear portion 22) with different diameters that rotate around the rotation axis X2 parallel to the rotation axes X1 of the drive shafts DA and DB. The large-diameter gear portion 21 and the small-diameter gear portion 22 rotate integrally around the rotation axis X2. A gear on the drive source side not shown meshes with the large-diameter gear portion 21. The final gear 31 of the differential mechanism 3 meshes with the small-diameter gear portion 22.

[0011] The final gear 31 has a disk-shaped base portion 310 surrounding the rotation axis X1 and a ring-shaped tooth portion 311 provided on the outer periphery of the base portion 310. The tooth portion 311 has a thickness T311 that crosses the base portion 310 in the rotation axis X1 direction.

[0012] The base portion 310 is inserted externally into a cylindrical joint portion 304 provided on the outer periphery of the differential case 30 and abuts against a flange portion 305 protruding from the joint portion 304 in the rotation axis X1 direction. In this state, the base portion 310 is joined to the differential case 30 by welding. Therefore, the final gear 31 rotates integrally with the differential case 30 around the rotation axis X1.

[0013] The differential case 30 houses a pair of bevel gears 32, 32 and a pair of side gears 33, 33 inside. A pinion mate shaft 34 supported by the differential case 30 is inserted through the pair of bevel gears 32, 32. The pair of side gears 33, 33 are spline-fitted to the drive shafts DA, DB. The drive shafts DA, DB respectively pass through the support cylinders 301, 302 of the differential case 30. Therefore, the drive shafts DA, DB rotate around the rotation axis X1 in conjunction with the rotation of the differential case 30.

[0014] Also, the vehicle 1 has a housing 10 that houses the differential mechanism 3. The housing 10 has a case member 11 and a cover member 12 that are joined to each other in the direction of the rotation axis X1 with the differential mechanism 3 interposed therebetween.

[0015] The case member 11 has a bottom wall portion 111 orthogonal to the rotation axis X1 and a peripheral wall portion 112 that surrounds the outer periphery of the bottom wall portion 111. The peripheral wall portion 112 is provided in the direction along the rotation axis X1. The front end surface 112a of the peripheral wall portion 112 is a flat surface orthogonal to the rotation axis X1. A cover member 12 is joined to the front end surface 112a of the peripheral wall portion 112 with bolts (not shown).

[0016] A through hole 111a penetrating in the direction of the rotation axis X1 is provided in the bottom wall portion 111. Also, a cylindrical bearing support portion 115 surrounding the through hole 111a is provided in the bottom wall portion 111. The bearing support portion 115 protrudes from the bottom wall portion 111 toward the cover member 12 side (right side in the figure) in the direction of the rotation axis X1.

[0017] A bearing B1 is supported on the inner periphery of the bearing support portion 115. The outer peripheral surface 301c of the support cylinder 301 of the differential case 30 is supported by the bearing support portion 115 via the bearing B1.

[0018] The bottom wall portion 111 of the case member 11 is provided in the radial direction of the rotation axis X1, in a range that crosses the final gear 31. The peripheral wall portion 112 extends along the outer diameter side of the final gear 31 in the direction of the rotation axis X1.

[0019] The bottom wall portion 111 has a thickened portion 116 on the surface facing the teeth portion 311 of the final gear 31 in the direction of the rotation axis X1. The thickened portion 116 spans both the bottom wall portion 111 and the peripheral wall portion 112. For example, a rotation sensor S for detecting the rotation of the final gear 31 is installed in the thickened portion 116. The rotation sensor S is connected to a control unit (not shown) via an electric wire Ca.

[0020] The rotation sensor S is fixed to the seating surface 116a of the thickened portion 116. The seating surface 116a is a flat surface perpendicular to the rotation axis X1. As will be described in detail later, the seating surface 116a is located at a position offset by a distance L116 toward the bottom wall portion 111 from the tip surface 112a of the peripheral wall portion 112.

[0021] The cover member 12 has a bottom wall portion 121 that intersects the rotation axis X1 in the region through which the rotation axis X1 passes, and a peripheral wall portion 122 that surrounds the outer circumference of the bottom wall portion 121. The peripheral wall portion 122 extends from the bottom wall portion 121 toward the case member 11 in the direction of the rotation axis X1.

[0022] The bottom wall portion 121 of the cover member 12 is provided with a through hole 121a that penetrates in the direction of the rotation axis X1. In the bottom wall portion 121, the area where the through hole 121a is provided is a cylindrical bearing support portion 125 that bulges out in the direction away from the case member 11 in the direction of the rotation axis X1.

[0023] A bearing B2 is supported on the inner circumference of the bearing support portion 125. The outer circumferential surface 302c of the support cylinder 302 of the differential case 30 is supported by the bearing support portion 125 via the bearing B2.

[0024] In the differential mechanism 3, both ends of the differential case 30 in the direction of the rotation axis X1 (support cylinders 301 and 302) are supported by the case member 11 and the cover member 12 via bearings B1 and B2, respectively. As a result, the differential case 30 is rotatable around the rotation axis X1.

[0025] In the differential mechanism 3, the differential case 30 and the final gear 31 are joined by welding. The end face 304a of the joint portion 304 of the differential case 30 and the end face 310a of the base portion 310 of the final gear 31 are flush. The welded portion P, which is the weld bead, is formed to straddle these end faces 304a and 310a. The welded portion P is formed in a ring shape that surrounds the rotating shaft X1 along the boundary line between the differential case 30 and the final gear 31 (see Figure 3).

[0026] In this embodiment, an optical 3D scanner 4 (see Figure 2) is used to determine, for example, whether the distance (radius r1) between the rotation axis X1 and the weld P is within a predetermined geometric tolerance. Specifically, the differential case 30 and the final gear 31 (hereinafter also referred to as workpiece W) are scanned with the 3D scanner 4, and then the shape data (3D model) of workpiece W obtained from the scan is compared with the original data (for example, CAD data) to determine its identity. Furthermore, the scanning performed by the 3D scanner 4 may be done using either a light (grid pattern) projection method or a laser beam cutting method.

[0027] As shown in Figure 2, the 3D scanner 4 includes a base 40 placed on a workbench (not shown), a rotary table 41 provided on the base 40, a work support base 42 fixed to the rotary table 41, a column 43 extending upward from the base 40, and a scanning unit 44 provided at the upper end of the column 43.

[0028] The rotary table 41 is mounted to be rotatable relative to the base 40 via an internal motor and bearings (not shown) (in the direction of the arrow in the figure). The workpiece support base 42 is mounted to be rotatable integrally with the rotary table 41 via bolts (not shown) or the like.

[0029] The workpiece support base 42 is a bottomed cylindrical shape with its opening facing upward. The workpiece support base 42 has a bottom wall portion 420 that is installed on the rotary table 41, and a cylindrical wall portion 421 that surrounds the outer circumference of the bottom wall portion 420 and extends upward from the bottom wall portion 420. The workpiece support base 42 is also provided with a support shaft 422 that protrudes upward from the bottom wall portion 420. The support shaft 422 is provided coaxially with the rotation axis of the rotary table 41.

[0030] The scanning unit 44 has two light-emitting units 441, 441 and one light-receiving unit 442. The light-emitting units 441, 441 are provided on one side and the other side of the light-receiving unit 442. The light-emitting unit 441 and the light-receiving unit 442 are positioned opposite the workpiece support base 42 in the vertical direction.

[0031] The workpiece W is inserted into the workpiece support base 42 through the upper opening. Specifically, the support cylinder 302 of the differential case 30 is fitted onto the support shaft 422, and the flange portion 305 of the differential case 30 abuts against the upper end surface 421a of the cylinder wall portion 421.

[0032] As a result, the workpiece W is set in the 3D scanner 4 with its rotating shaft X1 coaxial with the rotating shaft of the rotary table 41 (setting process). In addition, the final gear 31 and the support cylinder 301 side of the differential case 30 are positioned opposite the scanning unit 44 in the vertical direction, with a gap between them.

[0033] In the 3D scanner 4, the rotary table 41 is driven to rotate the workpiece W around the rotation axis X1, while the light-emitting units 441, 441 of the scanning unit 44 irradiate the workpiece W with scan light La, and the light-receiving unit 442 receives the reflected light Lb reflected from the workpiece W.

[0034] This creates a 3D model of the final gear 31 and the support cylinder 301 of the differential case 30 in the workpiece W. In this case, the rotation axis X1 can be identified in the created 3D model of the support cylinder 301 with respect to the outer surface 301c. Then, the distance (radius r1) between the rotation axis X1 and the weld P is measured and compared on both the 3D model and the CAD data.

[0035] In this embodiment, the support cylinder 301 and the welded portion P of the workpiece W constitute a measurement portion where measurements are taken on the 3D model, while other parts (for example, the joint portion 304 of the differential case 30, the final gear 31, etc.) constitute a non-measurement portion where measurements are not taken on the 3D model. Furthermore, in the measurement section, the support cylinder 301 constitutes the measurement reference section, which serves as the basis for measurement, and the welded section P constitutes the measurement target section, which is the object of measurement. The outer circumferential surface 301c of the support cylinder 301 constitutes the reference surface in the measurement reference section.

[0036] As shown in Figure 1, a bearing B1 is press-fitted into the support cylinder 301 of the differential case 30. Therefore, high dimensional accuracy is required for the support cylinder 301. Accordingly, the outer circumferential surface 301c of the support cylinder 301 is polished, and may have a stronger metallic luster and higher light reflectivity than other areas of the workpiece W (for example, the end face 304a of the joint portion 304 of the differential case 30, the end face 310a of the base portion 310 of the final gear 31, etc.). Furthermore, "high reflectivity" means that a large portion of the irradiated light is reflected, and the reflected light diffuses in unpredictable directions.

[0037] Therefore, as shown in Figure 2, when scanning light La is irradiated from the light-emitting unit 441 toward the workpiece W, the reflected light Lb reflected by the outer surface 301c of the support cylinder 301 toward the workpiece W has a large amount of light and is prone to scattering in unpredictable directions (diffuse reflection). On the other hand, stable reflection occurs in areas of the workpiece W other than the outer circumferential surface 301c of the support cylinder 301. "Stable reflection" refers to the reflection of an amount of light that can be appropriately received by the light receiving unit 442.

[0038] As a result, the light-receiving unit 442 may not be able to properly receive the reflected light Lb from the outer surface 301c, which can lead to a decrease in the accuracy of the 3D model around the support cylinder 301. Furthermore, if the accuracy of the 3D model around the support cylinder 301 is poor, the position of the rotation axis X1, which is the center of the support cylinder 301, will be inaccurate, and therefore the distance to the welded part P (radius r1) will also be an inaccurate measurement.

[0039] Therefore, in this embodiment, if there is an area in the workpiece W where the 3D scanner 4 may not be able to properly receive reflected light Lb, a scanning jig 7 is used to mask that area.

[0040] Figure 3 is a diagram illustrating the scanning jig 7. Figure 3 is a perspective view of the workpiece W in Figure 2, viewed from above. Note that Figure 3 shows the scanning jig 7 separated from the workpiece W. Figure 4 illustrates the scanning jig 7. Figure 4 schematically shows a cross-section along the rotation axis X1. Figure 4 also shows the scanning jig 7 mounted on the workpiece W.

[0041] As shown in Figure 3, the workpiece W according to this embodiment has a first region A1 (in the figure, the region without cross-hatching) where reflected light Lb is properly received, and a second region A2 (in the figure, the region with cross-hatching) where there is a risk that the light may not be properly received. Specifically, in the workpiece W, the outer surface 301c of the support cylinder 301, which is part of the measurement section (support cylinder 301 and welded section P), belongs to the second region A2. On the other hand, the surface of the joint 304 of the differential case 30, the side of the final gear 31, etc., which are not measurement sections, belong to the first region A1.

[0042] The scanning jig 7 is cylindrical in shape and is fitted onto the support cylinder 301. Specifically, it has a cylindrical base 70 that is aligned with the rotation axis X1. The inner diameter D70 of the base 70 is approximately the same as the outer diameter of the support cylinder 301. Also, the total length L70 of the base 70 is approximately the same as the total length of the support cylinder 301. The base 70 is fitted onto the support cylinder 301 in a position aligned with the rotation axis X1.

[0043] As shown in Figure 4, the differential case 30 is provided with a large-diameter portion 303 at the connection point between the support cylinder 301 and the joint portion 304, which has a larger diameter than the support cylinder 301. The large-diameter portion 303 is ring-shaped (see Figure 3) and surrounds the rotation axis X1. The large-diameter portion 303 has an end face 303a perpendicular to the outer circumferential surface 301c of the support cylinder 301 and an outer circumferential surface 303c perpendicular to the end face 304a of the joint portion 304. The large-diameter portion 303 is a non-measurement portion and belongs to the first region A1 (see Figure 3).

[0044] As shown in Figures 3 and 4, when the base 70 of the scanning jig 7 is set on the support cylinder 301 from above in the direction of the rotation axis X1 (masking step), the other end 70b of the base 70 in the direction of the rotation axis X1 abuts against the end face 303a of the large diameter portion 303, and one end 70a is set flush with the end face 301a of the support cylinder 301. In addition, the inner circumferential surface 70d of the base 70 is in contact with the outer circumferential surface 301c of the support cylinder 301 over its entire circumference.

[0045] As a result, the outer circumferential surface 301c of the support cylinder 301 is completely masked by the base 70. Therefore, the scan light La irradiated toward the outer circumferential surface 301c is blocked. In this case, the scanning jig 7 has a base 70 that constitutes a measurement section mask section that masks the support cylinder 301, which is the measurement section.

[0046] Here, the inner circumferential surface 70d of the base 70 contacts the outer circumferential surface 301c of the support cylinder 301 over its entire circumference. Therefore, misalignment between the base 70 and the support cylinder 301 is less likely to occur. As a result, when the base 70 is externally fitted onto the support cylinder 301, the center of the base 70 coincides with the axis of rotation X1. The outer circumferential surface 70c (reflective surface) of the base 70 takes on a shape (cylindrical shape) that conforms to the outer circumferential surface 301c of the support cylinder 301.

[0047] The outer circumferential surface 70c of the base 70, which serves as the reflective surface for the scan light La, is set to have a lower reflectivity than the outer circumferential surface 301c of the support cylinder 301, making it a reflective surface suitable for scanning. For example, the outer circumferential surface 70c of the base 70 can have a reflectivity similar to that of the joint 304 of the differential case 30 and the final gear 31.

[0048] For example, the outer surface 70c of the base 70 may be coated with a paint that appropriately reflects scan light La in order to make it a reflective surface suitable for scanning. The paint that appropriately reflects scan light La may be a fine powder or a liquid. Furthermore, a coating may be formed on the outer surface 70c of the base 70 by vapor deposition, sputtering, or the like to appropriately reflect light. Alternatively, the outer surface 70c may be roughened by shot blasting or the like. Furthermore, since the paint and coating applied to the outer surface 70c do not need to be removed, the scanning jig 7, once coated, can be used repeatedly.

[0049] As a result, in the 3D scanner 4, the scan light La emitted from the light-emitting unit 441 (see Figure 2) is appropriately reflected by the outer peripheral surface 70c of the base 70 of the scanning jig 7 and appropriately received by the light-receiving unit 442 (see Figure 2) (scanning process). In this case, the 3D model created will include a scanning jig 7 that is externally fitted to the support cylinder 301. In the 3D model including the scanning jig 7, the rotation axis X1 can be identified with respect to the outer circumferential surface 70c of the base 70. This allows for accurate measurement of the distance (radius r1) between the rotation axis X1 and the welded area P on the workpiece W.

[0050] After the 3D scanner 4 has finished scanning the workpiece W, the scanning jig 7 inserted into the support cylinder 301 is lifted and detached from the workpiece W (detachment process). Thus, the scanning jig 7 according to this embodiment can be easily attached to and detached from the workpiece W. Therefore, compared to, for example, applying powder to the surface of workpiece W, the effort and cost associated with post-processing such as powder treatment can be reduced.

[0051] In this embodiment, an example of a case where the 3D scanner 4 cannot properly receive reflected light Lb is shown as a case where the outer peripheral surface 301c of the support cylinder 301 is a highly reflective polished surface. However, the embodiment is not limited to this. Examples of cases in which the 3D scanner 4 cannot properly receive reflected light Lb include the following: (a) The support cylinder 301 is made of a transparent material such as glass or acrylic resin. In this case, the scan light La passes through the support cylinder 301. Therefore, the light receiving unit 442 (see Figure 2) may not be able to properly receive the reflected light Lb. (b) The outer surface 301c of the support cylinder 301 is black. In this case, the scan light La is absorbed by the outer surface 301c of the support cylinder 301. As a result, the light receiving unit 442 (see Figure 2) may not be able to properly receive the reflected light Lb. Here, "light transmission" refers to the situation where the irradiated scan light La passes through the workpiece W, preventing the light receiving unit 442 from receiving a sufficient amount of reflected light Lb. Furthermore, "light absorption" refers to the situation where the irradiated scan light La is absorbed by the workpiece W, preventing the light receiving unit 442 from receiving a sufficient amount of reflected light Lb.

[0052] Even in the cases shown in (a) and (b) above, by masking the outer circumferential surface 301c of the support cylinder 301 with the scanning jig 7, the scanning light La is properly reflected by the outer circumferential surface 70c of the base 70 of the scanning jig 7. As a result, the light receiving unit 442 (see Figure 2) can properly receive the reflected light Lb.

[0053] Furthermore, although the embodiment illustrates the case where the part to be measured is the welded part P, the part to be measured is not limited to the welded part P. For example, the part to be measured may be the large diameter portion 303 of the differential case 30 (see Figure 4). In this case, parallelism, angle, position, etc. can be measured at the end face 303a and the outer circumferential surface 303c of the large diameter portion 303.

[0054] The following are examples of scanning jigs 7 according to the embodiment. (1) The scanning jig 7 is used when scanning the workpiece W with the optical 3D scanner 4. The workpiece W has a first region A1 in which reflected light Lb is properly received by the light receiving unit 442 of the 3D scanner 4, and a second region A2 in which reflected light Lb is not properly received by the light receiving unit 442. The scanning jig 7 masks the second region A2 and has an outer surface 70c (reflective surface) that allows reflected light Lb to be properly received by the light receiving unit 442 of the 3D scanner 4.

[0055] In this case, if powder or other material is applied to the second area A2 of the workpiece W to secure a surface suitable for scanning, a process of cleaning the workpiece W after scanning to remove the powder is required. This increases the labor cost. In this case, it is conceivable to use a sublimation-type organic solvent that does not require cleaning, but this would involve a waiting time for the sublimation of the organic solvent, and there is a risk that the sublimated organic solvent may affect human health. Therefore, organic solvents require careful handling and investment in equipment such as exhaust systems. Therefore, by configuring the device as described above and providing a reflective surface suitable for scanning on the outer circumferential surface 70c of the scanning jig 7, it is possible to reduce the situation in which the reflected light Lb reflected by the outer circumferential surface 70c is not properly received by the light receiving unit 442 (for example, it may diffuse in an unpredictable direction, or be absorbed or transmitted). Therefore, even in workpieces W that have a second region A2 unsuitable for scanning, a surface suitable for scanning can be easily secured simply by masking the second region A2 with the outer surface 70c of the scanning jig 7. Furthermore, after scanning, it is only necessary to detach the scanning jig 7 from the workpiece W. Thus, the effort and cost of scanning workpieces W using an optical 3D scanner 4 can be reduced.

[0056] (3) The workpiece W has a support cylinder 301 and a welded part P, which are measurement parts where measurements are taken, and a large diameter part 303 of the differential case 30, a joint part 304 and a final gear 31, which are non-measurement parts where measurements are taken. The workpiece W has an outer circumferential surface 301c of the support cylinder 301 (at least a part of the measurement area) that belongs to the second region A2. The scanning jig 7 has a cylindrical base 70 (measuring mask portion) that is fitted onto the support cylinder 301. The base portion 70 masks the outer circumferential surface 301c of the support cylinder 301 (the portion belonging to the second region A2 in the measurement section) and blocks the scan light La irradiated from the light-emitting section 441 of the 3D scanner 4. The outer circumferential surface 70c (reflective surface) of the base portion 70 has a shape that conforms to the outer circumferential surface 301c (surface shape) of the support cylinder 301.

[0057] With this configuration, the base 70 of the scanning jig 7 has an inner circumferential surface 70d that contacts the outer circumferential surface 301c of the support cylinder 301 over its entire circumference, and an outer circumferential surface 70c that surrounds the inner circumferential surface 70d at a predetermined interval, making it less likely for misalignment to occur between the support cylinder 301 and the base 70. Therefore, the position of the rotation axis X1 can be determined from the shape of the outer circumferential surface 70c of the base 70. Therefore, even if the outer circumferential surface 301c of the support cylinder 301 is not suitable for scanning, scanning the outer circumferential surface 70c of the base portion 70, which has a shape that follows the outer circumferential surface 301c, will yield the same results as when the outer circumferential surface 301c is directly scanned to identify the rotation axis X1. This makes it possible to measure the radius r1 of the weld P being measured relative to the rotation axis X1 which serves as the reference axis for measurement. Furthermore, if the object of measurement is the large-diameter portion 303 of the differential case 30 (see Figure 4), parallelism, angle, position, etc., can also be measured at the end face 303a and outer circumferential surface 303c of the large-diameter portion 303.

[0058] (4) The workpiece W comprises a support cylinder 301 (measurement reference section) which serves as the measurement reference, and a welded section P (measurement target section) which is the subject of measurement, which constitute the measurement section. In the workpiece W, at least the support cylinder 301 of the measuring section belongs to the second region A2.

[0059] By configuring the device in this way and masking the outer surface 301c with the scanning jig 7, it is possible to reduce the situation in which the reflected light Lb is not properly received by the light receiving unit 442 (for example, by diffusing in an unpredictable direction, or by being absorbed or transmitted). As a result, the position of the rotation axis X1, which serves as the reference for measurement, can be determined. This makes it possible to measure the radius r1 of the weld P with respect to the rotation axis X1. Furthermore, if the measurement target is the large-diameter portion 303 of the differential case 30 (see Figure 4), the parallelism, angle, position, etc., of the end face 303a and outer circumferential surface 303c of the large-diameter portion 303 with respect to the rotation axis X1 can be measured.

[0060] (5) When the support cylinder 301 is set in the 3D scanner 4, it has a cylindrical outer surface 301c (reference surface) that is aligned with the direction of gravity. The base 70 of the scanning jig 7 is a cylindrical member that surrounds the outer circumferential surface 301c of the support cylinder 301.

[0061] With this configuration, the outer surface 301c can be masked simply by placing the scanning jig 7 over the support cylinder 301, which has a uniform thickness in the radial direction of the rotation axis X. Furthermore, after scanning is complete, the scanning jig 7 can be easily detached from the support cylinder 301.

[0062] (7) The outer surface 70c of the base 70 of the scanning jig 7 is coated with a paint that appropriately reflects the light from the 3D scanner 4.

[0063] With this configuration, the outer surface 301c of the base 70 of the scanning jig 7 can be easily made to have a reflectivity suitable for scanning simply by coating it with paint. Since the scanning jig 7, which is a separate component from the workpiece W, is coated, there is no need to remove the paint, and once coated, it can be used repeatedly.

[0064] Furthermore, the present invention can also be specified as a scanning method using a scanning jig 7. in particular, (8) A method for scanning a workpiece W using a scanning jig 7. The scanning method is: The placement process involves setting the workpiece W into the 3D scanner 4, A masking process in which the second region A2 of the workpiece W is masked with the scanning jig 7, The scanning process involves receiving the reflected light Lb of the scan light La irradiated onto the workpiece W from the 3D scanner 4 and scanning the workpiece W. The process includes a step of removing the scanning jig 7 from the workpiece W.

[0065] With this configuration, even in workpieces W that have a second region A2 unsuitable for scanning, a surface suitable for scanning can be easily secured simply by masking the second region A2 with the scanning jig 7. Furthermore, after scanning, it is only necessary to detach the scanning jig 7 from the workpiece W. Therefore, the number of post-processing steps can be reduced compared to, for example, applying powder to the surface of the workpiece W.

[0066] Furthermore, the present invention can also be specified as a 3D scanner 4 equipped with a scanning jig 7. in particular, (9) A 3D scanner 4 equipped with a scanning jig 7. 3D scanner 4 is The system comprises a light-emitting unit 441 that irradiates the workpiece W with scan light La, a light-receiving unit 442 that receives the reflected light Lb of the scan light La irradiated onto the workpiece W, and a workpiece support base 42 (support unit) that supports the workpiece W. With the workpiece W supported on the workpiece support base 42, the second region A2 is masked by the scanning jig 7. The light receiving unit 442 receives the reflected light Lb from the first region A1 of the workpiece W and the reflected light Lb from the outer surface 70c (reflective surface) of the scanning jig 7.

[0067] With this configuration, even in workpieces W that have a second region A2 that is unsuitable for scanning, a surface suitable for scanning can be easily secured simply by masking the second region A2 with the scanning jig 7. This eliminates the need to adjust the light intensity on the 3D scanner 4, thus reducing the effort required during scanning. Furthermore, it reduces the effort and cost associated with post-processing compared to, for example, applying powder to the surface of the workpiece W.

[0068] In the embodiment described above, an example was shown in which the outer peripheral surface 301c of the support cylinder 301 of the workpiece W is masked with a scanning jig 7 (see Figure 4). However, the embodiment is not limited to this. The scanning jig can be adapted to the distribution of the first region A1 and the second region A2 in the workpiece W. The following are examples of variations in scanning jigs depending on the distribution of the first region A1 and the second region A2.

[0069] (Variation 1) In the above embodiment, the measurement reference part of the measurement section is the support cylinder 301, and the measurement target part is the welded part P, and the case in which the distance (radius r1) between the rotation axis X1 and the welded part P is measured is illustrated. However, the method is not limited to this embodiment. For example, as shown in Figure 6, the part to be measured may be the teeth 311 of the final gear 31, and the distance (radius r2) between the rotation axis X1 and the outer circumferential surface 311c of the teeth 311 of the final gear 31 may be measured.

[0070] Figure 5 illustrates the scanning jig 7A according to Modification 1. In Figure 5, the scanning jig 7A is partially cut out to show a cross-section along the rotation axis X1 direction. Figure 6 illustrates the scanning jig 7A according to Modification 1. Figure 6 schematically shows a cross-section along the rotation axis X1. Figure 6 also shows the scanning jig 7A mounted on the workpiece WA. In the following description, components similar to those in the embodiment will be denoted by the same reference numerals, and detailed explanations will be omitted.

[0071] As shown in Figure 5, in the workpiece WA according to Modification 1, the end face 311a and inner circumferential surface 311b of the teeth 311 of the final gear 31 are polished, resulting in a higher light reflectivity than other areas. Specifically, in the workpiece WA, the end face 311a and inner circumferential surface 311b of the ring-shaped tooth portion 311, which is the part to be measured, belong to a second region A2 where reflected light Lb is not properly received (areas with cross-hatching in the figure). On the other hand, the outer circumferential surface 301c of the support cylinder 301, which is the measurement reference part, the surface of the large diameter portion 303, which is not measured, the surface of the joint portion 304, the surface of the base portion 310 of the final gear 31, and the outer circumferential surface 311c of the tooth portion 311, which is the part to be measured, belong to a first region A1 where reflected light Lb is properly received (areas without cross-hatching in the figure).

[0072] Therefore, even when scanning light La is shone toward the workpiece WA, the light receiving unit 442 (see Figure 2) may not be able to properly receive the reflected light Lb from the end face 311a and inner circumferential surface 311b of the tooth portion 311, which can result in poor accuracy of the 3D model around the tooth portion 311.

[0073] If the accuracy of the 3D model around the tooth portion 311 is poor, the position of the outer surface 311c of the tooth portion 311 will be inaccurate, and therefore the distance (radius r2) between the rotation axis X1 and the outer surface 311c of the final gear 31 will also be an inaccurate measurement. Therefore, the scanning jig 7A according to the modified example 1 is designed to mask the teeth 311 of the final gear 31.

[0074] As shown in Figure 5, the scanning jig 7A has a cylindrical portion 71 surrounding the rotation axis X1 and a flange portion 72 provided on the outer circumference of the cylindrical portion 71. As shown in Figure 6, the flange portion 72 is provided on one end 71a side of the cylindrical portion 71. The upper surface 72a of the flange portion 72 is flush with the one end 71a of the cylindrical portion 71. In a cross-sectional view along the rotation axis X1, the scanning jig 7A has a substantially L-shape.

[0075] The outer diameter R71 of the cylindrical portion 71 (see Figure 5) is approximately consistent with the inner diameter of the inner circumferential surface 311b of the tooth portion 311. The projection length L71 of the cylindrical portion 71 from the flange portion 72 (see Figure 6) is approximately consistent with the total length from the end face 310a of the base portion 310 of the final gear 31 to the end face 311a of the tooth portion 311. Furthermore, the outer diameter R72 of the flange portion 72 (see Figure 5) is approximately consistent with the outer diameter of the outer circumferential surface 311c of the tooth portion 311. The outer circumferential surface 72c of the flange portion 72 has a shape that conforms to the outer circumferential surface 311c (surface shape) of the tooth portion 311, which is the part of the measurement area that is to be measured.

[0076] As shown in Figures 5 and 6, when the scanning jig 7A is set on the workpiece WA from above in the direction of the rotation axis X1, the other end 71b of the cylindrical portion 71 comes into contact with the end face 310a of the base portion 310. The outer circumferential surface 71c of the cylindrical portion 71 comes into contact with the inner circumferential surface 311b of the tooth portion 311 over its entire circumference. Furthermore, the lower surface 72b of the flange portion 72 abuts against the end surface 311a of the tooth portion 311. The outer peripheral surface 72c of the flange portion 72 is positioned flush with the outer peripheral surface 311c of the tooth portion 311.

[0077] In the scanning jig 7A, one end 71a and the inner circumferential surface 71d of the cylindrical portion 71, which serve as the reflective surface for the scan light La, and the upper surface 72a and the outer circumferential surface 72c of the flange portion 72, are set to have a lower reflectivity than the end surface 311a and the inner circumferential surface 311b of the teeth portion 311 of the final gear 31, thus providing a reflective surface suitable for scanning.

[0078] As a result, as shown in Figure 6, in the teeth portion 311 of the final gear 31, the end face 311a is completely masked by the flange portion 72, and the inner circumferential surface 311b is completely masked by the cylindrical portion 71. Therefore, the scan light La irradiated toward the end face 311a and inner circumferential surface 311b of the tooth portion 311 is blocked. In this case, the scanning jig 7A has a cylindrical portion 71 and a flange portion 72 which constitute a measurement portion mask portion that masks the tooth portion 311, which is the measurement portion.

[0079] As a result, the scan light La is properly reflected by one end 71a and the inner circumferential surface 71d of the cylindrical portion 71 of the scanning jig 7A, and by the upper surface 72a and the outer circumferential surface 72c of the flange portion 72. Therefore, the light receiving unit 442 (see Figure 2) can properly receive the reflected light Lb.

[0080] Here, the outer circumferential surface 72c of the flange portion 72 is flush with the outer circumferential surface 311c of the tooth portion 311. Therefore, the flange portion 72 does not obstruct the scan light La that is irradiated onto the outer circumferential surface 311c of the tooth portion 311. Therefore, the flange portion 72 does not affect the accuracy of the 3D model around the outer surface 311c of the tooth portion 311. This allows for accurate measurement of the distance (radius r2) between the rotating axis X1 and the outer circumferential surface 311c of the tooth portion 311 in the workpiece WA.

[0081] (Modification 2) In the embodiments and modified example 1 described above, the case in which at least one of the measurement reference section and the measurement target section of the measurement unit belongs to the second region A2 was illustrated. However, the embodiment is not limited to this. For example, a part of the non-measurement section may belong to the second region A2.

[0082] Figure 7 illustrates the scanning jig 7B according to the modified example 2. In Figure 7, the scanning jig 7B is partially cut out and shown in cross-section along the rotation axis X1 direction. Figure 8 illustrates the scanning jig 7B according to Modification 2. Figure 8 schematically shows a cross-section along the rotation axis X1. Figure 8 also shows the scanning jig 7B mounted on the workpiece WB. Figures 7 and 8 illustrate the case where the distance (radius r1) between the rotation axis X1 and the weld P is measured.

[0083] As shown in Figure 7, in the workpiece WB according to the modified example 2, only the end face 303a and outer peripheral surface 303c of the large diameter portion 303 are polished, resulting in a higher light reflectivity than other areas. Specifically, the workpiece WB has the outer circumferential surface 301c and welded portion P of the support cylinder 301, which is the measurement portion, the surface of the joint portion 304 of the differential case 30, which is part of the non-measurement portion, and the surface of the final gear 31, all belonging to a first region A1 where reflected light Lb is properly received (the region without cross-hatching in the figure). On the other hand, the end face 303a and outer circumferential surface 303c of the large diameter portion 303, which is part of the non-measurement portion, belong to a second region A2 where reflected light Lb is not properly received (the region with cross-hatching in the figure).

[0084] Here, the large-diameter section 303, which is a non-measurement area, cannot be accurately measured after scanning, and therefore accurate shape data cannot be obtained. However, the large-diameter section 303 is located between the support cylinder 301 and the welded section P in the radial direction of the rotation axis X1. The support cylinder 301 and the welded section P are measurement areas where measurements are taken after scanning.

[0085] Therefore, when scanning light La is shone toward the workpiece WB, the reflected light Lb from the large-diameter section 303 may diffuse in an unpredictable direction, causing the light receiving section 442 (see Figure 2) to capture distorted light. As a result, the reflected light Lb from the support cylinder 301 and the welded section P may not be properly received. For example, if the reflected light Lb from the large-diameter portion 303 affects the support cylinder 301 side, there is a risk that the rotation axis X1 may not be able to be identified. Also, if the reflected light Lb from the large-diameter portion 303 affects the welded portion P side, there is a risk that the position of the welded portion P may not be able to be identified. Therefore, the scanning jig 7B according to the modified example 2 is designed to mask the large diameter portion 303 of the workpiece WB.

[0086] As shown in Figure 7, the scanning jig 7B has a disc-shaped bottom wall portion 73 surrounding the rotation axis X1, and a peripheral wall portion 74 surrounding the outer edge of the bottom wall portion 73 over its entire circumference. In a cross-sectional view along the rotation axis X1, the scanning jig 7B has a roughly L-shape.

[0087] The inner diameter D73 of the bottom wall portion 73 is approximately consistent with the outer diameter of the support cylinder 301. As shown in Figure 8, the inner diameter D74 of the peripheral wall portion 74 is approximately consistent with the outer diameter of the large diameter portion 303. Furthermore, the projection length L74 of the peripheral wall portion 74 from the bottom wall portion 73 is approximately consistent with the total length of the large diameter portion 303.

[0088] As shown in Figures 7 and 8, when the scanning jig 7B is set on the workpiece WB from above in the direction of the rotation axis X1, the support cylinder 301 passes through the inner circumferential surface 74d of the peripheral wall portion 74. The inner circumferential surface 73d of the bottom wall portion 73 contacts the outer circumferential surface 301c of the support cylinder 301 all the way around. Furthermore, the end face 74b of the peripheral wall portion 74 abuts against the end face 304a of the joint portion 304. The bottom face 73b of the bottom wall portion 73 abuts against the end face 303a of the large diameter portion 303.

[0089] Here, as shown in Figure 7, the upper surface 73a of the bottom wall portion 73 and the outer peripheral surface 74c of the peripheral wall portion 74 are set to the same reflectivity as the outer peripheral surface 70c of the base portion 70 (see Figure 3). In the scanning jig 7B, the upper surface 73a of the bottom wall portion 73 and the outer peripheral surface 74c of the peripheral wall portion 74, which serve as the reflective surfaces for the scan light La, are set to have a lower reflectivity than the end surface 303a and outer peripheral surface 303c of the large diameter portion 303, thus providing a reflective surface suitable for scanning.

[0090] As a result, as shown in Figure 8, the large-diameter portion 303 is masked over its entire end face 303a by the bottom wall portion 73, and the outer circumferential surface 303c is masked over its entire circumferential wall portion 74. Therefore, the scan light La irradiated toward the large-diameter portion 303 is blocked. In this case, the bottom wall portion 73 and the peripheral wall portion 74 of the scanning jig 7B constitute a mask portion that masks the large-diameter portion 303, which is part of the non-measurement portion.

[0091] The scan light La is appropriately reflected by the upper surface 73a of the bottom wall portion 73 and the outer peripheral surface 74c of the peripheral wall portion 74. Therefore, the light receiving unit 442 (see Figure 2) can appropriately receive the reflected light Lb. This reduces the likelihood of the 3D scanner 4 being unable to properly receive the reflected light Lb from the support cylinder 301 and the welded part P due to interference from the end face 303a and outer surface 303c of the large diameter portion 303. This allows for accurate measurement of the distance (radius r1) between the rotation axis X1 and the weld P in the workpiece WB.

[0092] The scanning jig 7B according to modified example 2 has the following configuration. (2) The workpiece WB has a support cylinder 301 and a welded part P which are measurement parts where measurements are taken, and a large diameter part 303 of the differential case 30, a joint part 304 and a final gear 31 which are non-measurement parts where measurements are taken. In the workpiece WB, the end face 303a and outer circumferential surface 303c (at least a portion of the non-measured area) of the large diameter portion 303 belong to the second region A2. The end face 303a and outer circumferential surface 303c of the large-diameter portion 303 (the portion belonging to the second region A2 in the non-measured area) have a higher reflectivity than the support cylinder 301 and the welded portion P (measured area). The scanning jig 7B has a bottom wall portion 73 and a peripheral wall portion 74 (mask portion) that mask the end face 303a and outer peripheral surface 303c of the large diameter portion 303, thereby blocking the scanning light La of the 3D scanner 4. The upper surface 73a of the bottom wall portion 73 and the outer peripheral surface 74c of the peripheral wall portion 74, which are reflective surfaces of the mask portion, have a lower reflectivity than the end surface 303a and outer peripheral surface 303c of the large diameter portion 303.

[0093] Even in areas where measurement is not performed (non-measurement areas), such as the large-diameter section 303, if there is a surface with high reflectivity, the reflected light Lb may affect the scanning of the support cylinder 301 and the welded section P (measurement area). For example, the reflected light Lb from the large-diameter section 303 may diffuse in an unpredictable direction, causing the 3D scanner 4 to capture distorted light, which can reduce the scanning accuracy. Therefore, by configuring it as described above, even in non-measurement areas, the surface of areas with high reflectivity is masked, preventing light from diffusing in unpredictable directions and enabling high-precision scanning.

[0094] (Variation 3) In the embodiments and modifications 1 and 2 described above, examples were given in which either the measuring portion or the non-measuring portion belongs to the second region A2. However, the embodiment is not limited to this. For example, a part of the measuring portion and a part of the non-measuring portion may belong to the second region A2.

[0095] Figure 9 is a diagram illustrating the scanning jig 7C according to modified example 3. Figure 10 illustrates the scanning jig 7C according to Modification 3. Figure 10 schematically shows a cross-section along the rotation axis X1. Figure 10 also shows the scanning jig 7C mounted on the workpiece WC.

[0096] As shown in Figure 9, in the workpiece WC according to the modified example 3, the outer circumferential surface 301c of the support cylinder 301 and the end face 303a and outer circumferential surface 303c of the large diameter portion 303 are polished, resulting in a higher light reflectivity than other areas. Specifically, in the workpiece WC, the welded portion P, which is part of the measurement area (the part to be measured), and the surface of the joint 304 of the differential case 30 and the surface of the final gear 31, which are part of the non-measurement area, belong to a first region A1 where reflected light Lb is properly received (the area without cross-hatching in the figure). On the other hand, the outer circumferential surface 301c of the support cylinder 301, which is part of the measurement area (the measurement reference area), and the end face 303a and outer circumferential surface 303c of the large diameter portion 303, which are part of the non-measurement area, belong to a second region A2 where reflected light Lb is not properly received (the area with cross-hatching in the figure).

[0097] As shown in Figure 10, the scanning jig 7C according to the modified example 3 is provided with a cylindrical portion 75 surrounding the rotating shaft X1 on the upper surface 73a of the bottom wall portion 73 of the scanning jig 7B (see Figure 7).

[0098] The inner diameter D75 of the cylindrical portion 75 is approximately consistent with the outer diameter of the support cylinder 301. Furthermore, the total length L7C of the scanning jig 7C, including the cylindrical portion 75 and the peripheral wall portion 74, is approximately consistent with the total length of the shaft portion, which consists of the support cylinder 301 and the large-diameter portion 303.

[0099] As shown in Figures 9 and 10, when the scanning jig 7C is set on the workpiece WC from above in the direction of the rotation axis X1, the inner circumferential surface 74d of the peripheral wall portion 74 contacts the outer circumferential surface 303c of the large diameter portion 303 all around. The inner circumferential surface 75d of the cylindrical portion 75 contacts the outer circumferential surface 301c of the support cylinder 301 all around. Furthermore, the end face 74b of the peripheral wall portion 74 abuts against the end face 304a of the joint portion 304. The bottom face 73b of the bottom wall portion 73 abuts against the end face 303a of the large diameter portion 303. The end face 75a of the cylindrical portion 75 is provided flush with the end face 301a of the support cylinder 301.

[0100] Here, as shown in Figure 9, the outer surface 75c of the cylindrical portion 75 is set to have the same reflectivity as the upper surface 73a of the bottom wall portion 73 and the outer surface 74c of the peripheral wall portion 74. In the scanning jig 7C, the upper surface 73a of the bottom wall portion 73, the outer peripheral surface 74c of the peripheral wall portion 74, and the outer peripheral surface 75c of the cylindrical portion 75, which serve as reflective surfaces for the scan light La, are set to have lower reflectivity than the outer peripheral surface 301c of the support cylinder 301 and the end surface 303a and outer peripheral surface 303c of the large diameter portion 303, thus providing reflective surfaces suitable for scanning.

[0101] As a result, as shown in Figure 10, the outer circumferential surface 301c of the support cylinder 301 is completely masked by the cylindrical portion 75. The end face 303a of the large diameter portion 303 is completely masked by the bottom wall portion 73. The outer circumferential surface 303c of the large diameter portion 303 is completely masked by the peripheral wall portion 74. Therefore, the scan light La irradiated toward the support cylinder 301 and the large-diameter portion 303 is shielded. In this case, the bottom wall portion 73 and peripheral wall portion 74 of the scanning jig 7C constitute a mask portion that masks the large-diameter portion 303, which is part of the non-measurement portion.

[0102] The scan light La is appropriately reflected by the upper surface 73a of the bottom wall portion 73, the outer surface 74c of the peripheral wall portion 74, and the outer surface 75c of the cylindrical portion 75. Therefore, the light receiving unit 442 (see Figure 2) can appropriately receive the reflected light Lb. This allows for accurate measurement of the distance (radius r1) between the rotation axis X1 and the weld P in the workpiece WC.

[0103] (Modification 4) In the above-described modified example 3, the distance (radius r1) between the rotating shaft X1 and the welded part P is measured when the support cylinder 301, which is the measurement reference part, and the large-diameter part 303, which is part of the non-measurement part, belong to the second region A2. However, the invention is not limited to this embodiment. For example, when the teeth 311 of the final gear 31, which is the part to be measured, and the base part 310, which is part of the non-measurement part, belong to the second region A2, the distance (radius r2) between the rotating shaft X1 and the outer circumferential surface 311c of the teeth 311 of the final gear 31 may be measured.

[0104] Figure 11 is a diagram illustrating the scanning jig 7D according to the modified example 4. In Figure 11, the scanning jig 7D is partially cut out to show a cross-section along the rotation axis X1 direction. Figure 12 illustrates the scanning jig 7D according to Modification 4. Figure 12 schematically shows a cross-section along the rotation axis X1. Figure 12 also shows the scanning jig 7D mounted on the workpiece WD.

[0105] As shown in Figure 11, in the workpiece WD according to the modified example 4, the end face 310a of the base 310 of the final gear 31, the end face 311a of the teeth 311, and the inner circumferential surface 311b are polished, resulting in a higher light reflectivity than other areas. Specifically, in the workpiece WD, the end face 311a and inner circumferential surface 311b of the tooth portion 311, which is the part to be measured, and the end face 310a of the base portion 310, which is part of the non-measurement portion, belong to a second region A2 where reflected light Lb is not properly received (areas with cross-hatching in the figure). On the other hand, the outer circumferential surface 301c of the support cylinder 301, which is the measurement reference portion, the surface of the large diameter portion 303, which is part of the non-measurement portion, the surface of the joint portion 304, and the outer circumferential surface 311c of the tooth portion 311, which is the part to be measured, belong to a first region A1 where reflected light Lb is properly received (areas without cross-hatching in the figure).

[0106] As shown in Figure 11, the scanning jig 7D according to the modified example 4 is the scanning jig 7A (see Figure 5) described above, with a disc-shaped bottom wall portion 76 that narrows the opening of the cylindrical portion 71. As shown in Figure 12, the inner diameter D76 of the bottom wall portion 76 is slightly larger than the diameter of the welded portion P. The lower surface 76b of the bottom wall portion 76 is flush with the other end 71b of the cylindrical portion 71.

[0107] As shown in Figures 11 and 12, when the scanning jig 7D is set on the workpiece WD from above in the direction of the rotation axis X1, the lower surface 76b of the bottom wall portion 76 comes into contact with the end surface 310a of the base portion 310 of the final gear 31. The outer circumferential surface 71c of the cylindrical portion 71 comes into contact with the inner circumferential surface 311b of the teeth portion 311 over its entire circumference. Furthermore, the lower surface 72b of the flange portion 72 abuts against the end surface 311a of the tooth portion 311. The outer peripheral surface 72c of the flange portion 72 is positioned flush with the outer peripheral surface 311c of the tooth portion 311.

[0108] In the scanning jig 7D, one end 71a and the inner circumferential surface 71d of the cylindrical portion 71, the upper surface 72a and the outer circumferential surface 72c of the flange portion 72, and the upper surface 76a and the inner circumferential surface 76d of the bottom wall portion 76, which are the reflective surfaces of the scan light La, are set to have a lower reflectivity than the inner circumferential surface 311b of the tooth portion 311, the end surface 311a, and the end surface 310a of the base portion 310, thus providing reflective surfaces suitable for scanning.

[0109] As a result, as shown in Figure 12, in the final gear 31, the end face 311a of the tooth portion 311 is completely masked by the flange portion 72. The inner circumferential surface 311b of the tooth portion 311 is completely masked by the cylindrical portion 71. The end face 310a of the base portion 310 is completely masked by the bottom wall portion 76. Therefore, the scan light La irradiated toward the end face 310a of the base portion 310, the end face 311a of the tooth portion 311, and the inner circumferential surface 311b is shielded. In this case, the bottom wall portion 76 of the scanning jig 7D constitutes a mask portion that masks the end face 310a of the base portion 310, which is part of the non-measurement portion.

[0110] As a result, the scan light La is properly reflected by the upper surface 76a and inner surface 76d of the bottom wall portion 76 of the scanning jig 7D, one end 71a and inner surface 71d of the cylindrical portion 71, and the upper surface 72a and outer surface 72c of the flange portion 72. Therefore, the light receiving unit 442 (see Figure 2) can properly receive the reflected light Lb. Therefore, the distance (radius r2) between the rotating axis X1 and the outer circumferential surface 311c of the tooth portion 311 can be accurately measured in the workpiece WD.

[0111] (Other examples) Although not shown in the illustrations, in the workpieces WA and WD according to modified examples 1 and 4 (see Figures 5 and 11), for example, the outer surface 301c of the support cylinder 301, which is the measurement reference section, may be further polished and belong to the second region A2. In this case, the aforementioned scanning jig 7 (see Figure 3) can be set on the support cylinder 301 in conjunction with the scanning jigs 7A and 7D. Furthermore, if the large-diameter portion 303, which is part of the non-measurement area, is polished and belongs to the second region A2, then scanning jigs 7B and 7C (see Figures 7 and 9) can be used in conjunction with scanning jigs 7A and 7D. In this way, the scanning jigs 7 to 7D can be appropriately combined depending on the distribution of the second region A2 in the workpiece W.

[0112] (Variation 5) In the embodiments and modifications 1 to 4 described above, examples were given of using scanning jigs 7 to 7D to measure the distance (radius r1) between the rotating shaft X1 and the welded part P, or the distance (radius r2) between the rotating shaft X1 and the outer peripheral surface 311c of the teeth 311 of the final gear 31 (see Figures 3 to 12). However, the invention is not limited to this embodiment. For example, as shown in Figure 1, in the case member 11 of the housing 10, scanning jig 7E can also be used to measure the distance L116 between the tip surface 112a of the peripheral wall portion 112 and the seating surface 116a of the rotating sensor S.

[0113] Figure 13 is a diagram illustrating the case member 11. Figure 13 is a view of the case member 11 in Figure 1, as seen from the cover member 12 side. Figure 14 illustrates the scanning jig 7E according to the modified example 5. Figure 14 shows the case member 11 in a state set on the 3D scanner 4. Figure 14 also shows a schematic diagram of the case member 11 along the rotation axis X1.

[0114] As shown in Figure 14, in Modification 5, a 3D scanner 4 is used to determine whether the distance L116 between the tip surface 112a (reference surface) of the peripheral wall portion 112 (measurement reference portion) of the case member 11 (workpiece) and the seating surface 116a (measurement target portion) is within a predetermined geometric tolerance.

[0115] The case member 11 is set on the work support base 42A of the 3D scanner 4 with the opening of the peripheral wall portion 112 facing upward. The work support base 42A has a support shaft 422A and a cylindrical wall portion 421A for positioning the case member 11. When the case member 11 is set on the work support base 42A, the front end surface 112a of the peripheral wall portion 112 faces the light-emitting portion 441 and light-receiving portion 442 of the scanning portion 44 with a gap between them.

[0116] Here, as shown in Figure 13, the tip surface 112a of the peripheral wall portion 112 of the case member 11 may require high flatness in order to join seamlessly with the cover member 12 (see Figure 1). Therefore, the tip surface 112a of the peripheral wall portion 112 may have a stronger metallic luster and higher light reflectivity than other parts of the case member 11, for example, by being milled from the front.

[0117] The case member 11 has a front end surface 112a of the peripheral wall portion 112 that belongs to a second region A2 (the region with cross-hatching in the figure) where reflected light Lb is not properly received. On the other hand, the case member 11 has other parts, such as the surface of the bottom wall portion 111, the surface of the bearing support portion 115, and the seating surface 116a, that belong to a first region A1 (the region without cross-hatching in the figure) where reflected light Lb is properly received.

[0118] Therefore, as shown in Figure 14, when scanning light La is irradiated from the light-emitting unit 441 toward the case member 11, the reflected light Lb reflected by the tip surface 112a of the peripheral wall portion 112 of the case member 11 has a large amount of light and is prone to scattering in unpredictable directions (diffuse reflection). As a result, the light-receiving unit 442 may not be able to properly receive the reflected light Lb from the tip surface 112a, and the 3D model of the case member 11 may have poor accuracy around the tip surface 112a of the peripheral wall portion 112. Poor accuracy around the tip surface 112a of the peripheral wall portion 112 results in an inaccurate measurement of the distance L116 to the seating surface 116a.

[0119] Therefore, in modification 5, a scanning jig 7E is used in the case member 11 to mask the tip surface 112a of the peripheral wall portion 112. As shown in Figure 14, the scanning jig 7E is formed in an annular shape along the peripheral wall portion 112 when viewed from the direction of the rotation axis X1. The scanning jig 7E has a plate-shaped base portion 77 perpendicular to the rotation axis X1 and a protruding wall portion 78 that protrudes from the outer peripheral edge of the base portion 77.

[0120] In a direction perpendicular to the rotation axis X1, the width W77 of the base portion 77 is approximately consistent with the width of the tip surface 112a of the peripheral wall portion 112. Furthermore, the base portion 77 is set to have a uniform thickness T77 around its entire circumference of the rotation axis X1.

[0121] When the scanning jig 7E is set onto the case member 11 from above, the protruding wall portion 78 is fitted onto the peripheral wall portion 112, and the lower surface 77b of the base portion 77 comes into contact with the front end surface 112a of the peripheral wall portion 112. This maintains the state in which the base portion 77 overlaps the peripheral wall portion 112. In addition, the inner circumferential surface 77d of the base portion 77 remains flush with the inner circumferential surface 112d of the peripheral wall portion 112.

[0122] In the scanning jig 7E, the upper surface 77a and inner circumferential surface 77d of the base portion 77, which serve as the reflective surfaces for the scan light La, and the outer circumferential surface 78c of the protruding wall portion 78 are set to have a lower reflectivity than the tip surface 112a of the circumferential wall portion 112, thus providing reflective surfaces suitable for scanning.

[0123] As a result, in the case member 11, the tip surface 112a of the peripheral wall portion 112 is masked over its entire surface by the base portion 77. Therefore, the scan light La irradiated from the light-emitting unit 441 toward the tip surface 112a of the peripheral wall unit 112 is blocked. In this case, the base 77 of the scanning jig 7E constitutes a measurement unit mask unit that masks the tip surface 112a of the peripheral wall unit 112, which is part of the measurement unit.

[0124] As a result, the scan light La is properly reflected by the upper surface 77a and inner surface 77d of the base 77 of the scanning jig 7E, and by the outer surface 78c of the protruding wall portion 78. Therefore, the light receiving unit 442 can properly receive the reflected light Lb.

[0125] In this case, the 3D model of the case member 11 created by scanning will include the scanning jig 7E superimposed on the peripheral wall portion 112. Therefore, the distance L116' between the upper surface 77a of the base portion 77 and the seating surface 116a will be measured from the 3D model.

[0126] Here, it is known in advance that the base 77 of the scanning jig 7E has a uniform thickness T77 around the entire circumference of the rotation axis X1. Therefore, in the 3D model, the distance L116 obtained by subtracting the thickness T77 of the base 77 from the distance L116' between the upper surface 77a of the base 77 and the seating surface 116a can be identified as the distance L116 between the tip surface 112a of the peripheral wall 112 and the seating surface 116a (L116 = L116' - T77).

[0127] Furthermore, the scanning jig 7E is designed so that its position on the case member 11 does not shift or fall off during scanning, by externally fitting the protruding wall portion 78 onto the peripheral wall portion 112. Furthermore, the inner circumferential surface 77d of the base portion 77 is flush with the inner circumferential surface 112d of the peripheral wall portion 112. This prevents the scan light La irradiated from the light-emitting portion 441 toward the seating surface 116a from being obstructed by the base portion 77.

[0128] The scanning jig 7E according to modified example 5 has the following configuration. (6) The peripheral wall portion 112 (measurement reference portion) of the case member 11 (workpiece) has a tip surface 112a (reference surface) that intersects with the direction of gravity when set in the 3D scanner 4. The scanning jig 7E has a plate-shaped base 77 (measurement mask portion). The base portion 77 is positioned overlapping the tip surface 112a of the peripheral wall portion 112.

[0129] With this configuration, the tip surface 112a of the peripheral wall portion 112 of the case member 11 can be easily masked by simply placing the plate-shaped base portion 77 over the tip surface 112a of the peripheral wall portion 112 of the case member 11 from above.

[0130] The embodiments and modifications 1 to 5 described above illustrate the measurement of the distance (radii r1, r2) between the measurement reference part and the part to be measured, but the method is not limited to this embodiment. For example, it can also be used to measure positional accuracy, parallelism, perpendicularity, etc., between the measurement reference part and the part to be measured.

[0131] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments shown. It can be modified as appropriate within the scope of the technical idea of ​​the invention. [Explanation of Symbols]

[0132] 3: Differential mechanism 4: 3D Scanner 7, 7A~7E: Scanning fixtures 11: Case components (workpiece) 30: Differential case (workpiece) 31: Final Gear (Work) 42: Work support stand (support part) 44: Scanning section 70: Base (measurement mask section) 71: Cylindrical section (measurement mask section) 72: Flange section (measurement section mask section) 73: Bottom wall section (mask section) 74: Peripheral wall (mask area) 75: Tube section (measuring mask section) 76: Bottom wall section (mask section) 77: Base (measurement mask section) 78:Protruding wall part 70c, 72c, 74c, 75c, 78c: Outer surface (reflective surface) 71a: One end (reflective surface) 72a, 73a, 76a, 77a: Top surface (reflective surface) 71d, 76d, 77d: Inner peripheral surface (reflective surface) 112: Peripheral wall part (measurement reference part) 112a: Tip surface (reference surface) 116a: Seating surface (measurement target area) 301: Support tube 301c: Outer surface (measurement part, measurement reference part) 303: Large diameter section 303a: End face (non-measurement part) 303c: Outer surface (non-measurement part) 304: Joint 304a: End face 310: Base 310a: End face 311: Tooth area (measurement area, measurement target area) 311a: End face 311b: Inner surface 311c: Outer surface 441: Lighting unit 442: Light receiving part A1:First area A2:Second area La: Scanning light Lb: Reflected light P: Welded area (measurement area, measurement target area) W, WA~WE: Work X1: Rotation axis

Claims

1. A scanning jig used when scanning a workpiece with an optical 3D scanner, The workpiece has a first region where reflected light is properly received by the 3D scanner, and a second region where the reflected light is not properly received by the 3D scanner. The scanning jig is a scanning jig that masks the second region and has a reflective surface that allows the reflected light to be appropriately received by the 3D scanner.

2. In claim 1, The workpiece has a measuring section where measurement is performed and a non-measuring section where measurement is not performed. The workpiece has at least a portion of the non-measurement area that belongs to the second region, The portion of the non-measured section belonging to the second region has a higher reflectivity than the measuring section. The scanning jig has a mask portion that masks the portion of the non-measurement section belonging to the second region, thereby blocking the light from the 3D scanner. A scanning jig wherein the reflective surface of the mask portion is set to have a reflectance lower than that of the portion belonging to the second region in the non-measurement portion.

3. In claim 1, The workpiece has a measuring section where measurement is performed and a non-measuring section where measurement is not performed. The workpiece has at least a portion of the measuring section belonging to the second region, The scanning jig has a measurement section mask portion that masks the portion of the measurement section belonging to the second region, thereby blocking the light from the 3D scanner. The reflective surface of the mask portion of the measuring portion has a shape that conforms to the surface shape of the measuring portion, in the scanning jig.

4. In claim 3, The measurement unit comprises a measurement reference unit that serves as the basis for measurement, and a measurement target unit that is the object of measurement. The measurement unit is a scanning jig in which at least the measurement reference unit belongs to the second region.

5. In claim 4, The measurement reference section has a cylindrical reference surface aligned with the direction of gravity, The measurement mask portion is a cylindrical member surrounding the reference surface, which is a scanning jig.

6. In claim 4, The aforementioned measurement reference section has a reference plane that intersects with the direction of gravity, The measurement mask portion is a plate-shaped member that is placed on top of the reference surface, and is a scanning jig.

7. In claim 1, A scanning jig, wherein the reflective surface is coated with a paint that appropriately reflects the light from the 3D scanner.

8. A method for scanning a workpiece using a scanning jig according to any one of claims 1 to 7, A positioning step of setting the workpiece in the 3D scanner, A masking step of masking the second region with the scanning jig, A scanning step in which the 3D scanner receives reflected light from the workpiece and scans the workpiece, A scanning method comprising a detachment step of removing the scanning jig from the workpiece.

9. A 3D scanner comprising a scanning jig according to any one of claims 1 to 7, The aforementioned 3D scanner is The system comprises a light-emitting unit that irradiates light onto the workpiece, a light-receiving unit that receives reflected light from the workpiece, and a support unit that supports the workpiece. The workpiece is supported by the support portion, and the second region is masked by the scanning jig. The light-receiving unit is a 3D scanner that receives reflected light from the first region of the workpiece and reflected light from the reflective surface of the scanning jig.

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