Gear tooth contact inspection device and method

Abstract

A gear tooth contact inspection according to the present invention comprises a processing device configured so as to acquire captured image data of a gear including a target tooth surface having a tooth contact mark made visible by using paint, generate a gear image including the target tooth surface from the captured image data, acquire 3D model data of the gear, generate AR composite data in which the gear image is superimposed on a virtual gear of a three-dimensional spatial coordinate system generated from the 3D model data, and evaluate the tooth contact state on the basis of a tooth contact region corresponding to the tooth contact mark in the AR composite data.

Description

Gear tooth contact inspection device and method

[0001] The present disclosure relates to an apparatus used for inspecting tooth contact of a gear and a tooth contact inspection method using the same.

[0002] Tooth contact is one of the factors that affect gear noise, transmitted power, and transmission efficiency, and tooth contact inspections are performed during gear assembly and maintenance. In tooth contact inspections, an operator applies paint to the tooth surfaces, engages the gears, transfers the paint scraped off by the meshing or the remaining paint onto tape, and visually inspects the transferred paint to evaluate the center of gravity and area of ​​the tooth contact. However, this conventional inspection method has issues such as reduced accuracy due to stains on the transferred paint tape and unclear tooth surface contours, and is dependent on the skill of the operator. Therefore, a method has been proposed for quantitative gear tooth contact inspection that does not rely on the operator's visual and sensory inspection.

[0003] For example, the gear tooth contact inspection method described in Patent Document 1 involves applying paint to the inspection surface of the gear to be inspected or to the meshing surface of the gear that meshes with this gear, transferring the remaining paint on the inspection surface that peels off as the gear pair rotates onto tape, photographing the tape with the transferred paint using a camera, and processing the resulting image data using a computer to inspect the tooth contact condition on the inspection surface.

[0004] Japanese Patent Application Laid-Open No. 2005-98911

[0005] However, the method of Patent Document 1 does not clarify how to identify the area of ​​the surface to be inspected, and does not provide information such as the dimensions and positions of the tooth contact points on the tooth surface and the errors contained therein.

[0006] The present disclosure has been made in consideration of the above circumstances, and its purpose is to improve the measurement accuracy of the dimensions and positions of tooth contact on the tooth surface in gear tooth contact inspection.

[0007] In order to solve the above problems, a tooth contact inspection device according to one aspect of the present disclosure includes a processing device configured to: acquire photographed image data of a gear including a target tooth surface having tooth contact marks visualized by paint; generate a gear image including the target tooth surface from the photographed image data; acquire 3D model data of the gear; generate AR composite data by superimposing the gear image on a virtual gear in a three-dimensional coordinate system generated from the 3D model data; and evaluate the tooth contact state based on the tooth contact area corresponding to the tooth contact mark in the AR composite data.

[0008] Furthermore, a tooth contact inspection method according to one aspect of the present disclosure is a tooth contact inspection method for gears performed by a computer, and includes: acquiring photographed image data of a gear including a target tooth surface having tooth contact marks visualized with paint; acquiring 3D model data of the gear; generating a gear image including the target tooth surface from the photographed image data; generating AR composite data in which the gear image is superimposed on a virtual gear in a three-dimensional spatial coordinate system generated from the 3D model data; and evaluating a tooth contact state based on a tooth contact area corresponding to the tooth contact mark in the AR composite data.

[0009] According to the present disclosure, it is possible to improve the measurement accuracy of the dimensions and positions of the tooth contact on the tooth surface in gear tooth contact inspection.

[0010] Fig. 1 is a functional block diagram of a gear tooth contact inspection device according to an embodiment of the present disclosure. Fig. 2 is a block diagram showing a schematic configuration of a processing device provided in the tooth contact inspection device. Fig. 3 is a flowchart showing processing by the processing device provided in the tooth contact inspection device. Fig. 4 is an example of a gear image. Fig. 5 is an example of AR composite data. Fig. 6 is an example of AR composite data showing a tooth contact region.

[0011] Next, an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a functional block diagram of a gear tooth contact inspection device 1 according to an embodiment of the present disclosure. The tooth contact inspection device 1 shown in Fig. 1 includes an imaging device 2 and a processing device 3. The tooth contact inspection device 1 is a device that inspects the tooth contact of a pair of meshing gears.

[0012] <<Imaging Device 2>> The imaging device 2 includes a camera 21 that captures an image of the gear 5 to be inspected out of the gear pair, and an illumination device 22 that illuminates the field of view of the camera 21.

[0013] The camera 21 is attached, for example, via a jig to a casing that houses the gear 5. The camera 21 may be detachable from the casing so that it can be installed at any time, such as during assembly or maintenance. The field of view of the camera 21 includes at least one tooth surface of the gear 5 to be inspected. The camera 21 is, for example, a 2D camera equipped with a CCD image sensor, and the camera 21 captures images and generates two-dimensional captured image data. However, the camera 21 may also be a 3D camera. In this case, the camera 21 is, for example, a stereo 3D camera, and the camera 21 captures images and generates three-dimensional captured image data.

[0014] The lighting device 22 projects direct light or indirect light toward the field of view of the camera 21. The lighting device 22 is equipped with a light source suitable for the imaging method of the camera 21. The lighting device 22 is attached to the casing via a jig, for example, in the same way as the camera 21. The lighting device 22 may be disposed integrally with the camera 21, or may be disposed separately from the camera 21.

[0015] <<Processing Device 3>> The processing device 3 acquires photographed image data from the imaging device 2 and processes the photographed image data to analyze tooth contact and generate tooth contact inspection results based on the analysis results. The processing device 3 has functional units, namely, an image processing unit 31 that analyzes the tooth contact state by image processing, and an inspection unit 32 that evaluates the tooth contact state based on the analysis results. The specific processing content of each functional unit will be described in detail later.

[0016] Fig. 2 is a block diagram showing a schematic configuration of the processing device 3 included in the tooth contact inspection device 1. As shown in Fig. 2, the processing device 3 can be realized by a computer including a CPU (Central Processing Unit), a memory, an auxiliary storage device such as an HDD (Hard Disk Drive), a communication I / F for connecting to a communication network or the imaging device 2 by wire or wirelessly, an input device such as a mouse, a keyboard, a touch sensor, or a touch panel, an output device such as a display, and a media I / F for reading and writing information from and to a portable storage medium.

[0017] Each function of the processing device 3 can be realized by loading a predetermined program stored in an auxiliary storage device into memory and executing it with the CPU. Communication between the processing device 3 and the imaging device 2 can be realized, for example, by the CPU using a communication I / F. Note that the predetermined program may be downloaded to the processing device 3 from a network via the communication I / F, or may be loaded to the processing device 3 from a storage medium connected to the media I / F.

[0018] The processing device 3 may be located near or remote from the imaging device 2. An example of a case in which the processing device 3 is located remotely from the imaging device 2 is where the imaging device 2 is located at an assembly site for a product incorporating the gear 5, and the processing device 3 is built on a web server or located in an office.

[0019] Returning to FIG. 1, an image database 35, a 3D reference database 36, and a gear database 37 are constructed in the auxiliary storage device of the processing device 3.

[0020] The image database 35 stores an image file 351. The image file 351 is image data obtained by capturing an image with the imaging device 2, linked to a gear ID. The gear ID is information unique to the gear 5, and the gear 5 can be identified using the gear ID. The captured image data may include capturing information such as the date and time of capture and the number of colors in addition to digital data of the captured image. The CPU of the processing device 3 stores the captured image data obtained from the imaging device 2 in the image database 35, linked to the gear ID. Furthermore, the CPU of the processing device 3 can read out, based on the gear ID, an image file 351 containing captured image data of the gear 5 identified by the gear ID from the image database 35.

[0021] The 3D reference database 36 stores a 3D model file 361. The 3D model file 361 is 3D model data, which is model data of the three-dimensional shape of the tooth flank of the gear 5, linked to a gear ID. Based on the gear ID, the CPU of the processing device 3 can read the 3D model file 361 containing the 3D model data of the gear 5 identified by the gear ID from the 3D reference database 36. The 3D model data of the gear 5 may be data obtained by measuring the actual gear 5 with a coordinate measuring machine or computer-aided design data of the gear 5. The 3D model data may include three-dimensional shape data of the tooth flanks of all teeth of the gear 5, or may include three-dimensional shape data of the tooth flanks of one or more teeth arranged in the circumferential direction. For example, measuring the gear 5 with a non-contact coordinate measuring machine generates point cloud data containing positional information (x, y, z) of the tooth flank of the gear 5 in a predetermined three-dimensional coordinate system. The point cloud data is then polygonized to generate STL data of the tooth flank shape. The STL data may be converted to 3DXML data. The STL data or 3DXML data of this tooth flank shape can be used as 3D model data. Note that the data format of the 3D model data may be other three-dimensional data formats.

[0022] The 3D reference database 36 also stores a tooth surface information file 362. The tooth surface information file 362 stores coordinate position information and field angle information of the ridge line of the tooth surface of the gear 5 when the 3D model is mapped, linked to the gear ID. The ridge line of the tooth surface is a line connecting the boundary between the tooth tip (or at least one of the tooth base, large diameter end, and small diameter end) and the tooth surface. The coordinate position information of the ridge line of the tooth surface is generated and updated by the image processing unit 31. The field angle is information on three-dimensional spatial coordinates when a virtual gear, described later, is displayed on the screen, and the field angle information is generated and updated by processing by the image processing unit 31. The tooth surface information file 362 is used in combination with the 3D model file 361.

[0023] The gear database 37 stores gear files 371. The gear files 371 hold product information of the gears 5, such as product number information, manufacturer information, structural information such as dimensions and number of teeth, and design drawing information. One gear file 371 is associated with a gear ID.

[0024] The gear database 37 also stores a criterion file 372. The criterion file 372 holds information related to the criterion for tooth contact inspection. The data in the criterion file 372 may be combined with the gear file 371. The criterion for tooth contact inspection differs for each gear 5 product, and may also differ for each individual gear 5. When the criterion for tooth contact inspection differs for each gear 5 product, one criterion file 372 is associated with each gear 5 product. When the criterion for tooth contact inspection differs for each gear 5, one criterion file 372 is associated with each gear ID.

[0025] <Tooth Contact Inspection Method> A tooth contact inspection method using the tooth contact inspection device 1 having the above configuration will now be described with reference to Fig. 3. Fig. 3 is a flow chart of processing by the processing device 3 included in the tooth contact inspection device 1.

[0026] In this embodiment, paint is applied to the tooth surface of the gear 5 that is not the subject of inspection in the gear pair, the gear pair is rotated, and the paint is transferred to the tooth surface of the subject of inspection gear 5, thereby visualizing the tooth contact marks of the gear 5. However, it is also possible to apply paint to the tooth surface of the subject of inspection gear 5 in the gear pair, rotate the gear pair, and visualize the tooth contact marks of the gear 5 by the paint remaining on the tooth surface of the subject of inspection gear 5. For convenience of explanation, the tooth surface of the subject of observation that has tooth contact marks visualized by paint in this way will be referred to as the "subject tooth surface 50."

[0027] The imaging device 2 captures an image of a part or the whole of the gear 5 including the target tooth surface 50, and generates captured image data. This captured image data is output from the imaging device 2 to the processing device 3 and stored in the image database 35 as an image file 351 associated with the gear ID.

[0028] The image processing unit 31 of the processing device 3 reads out the corresponding image file 351 from the image database 35 based on the gear ID of the gear 5 to be inspected, and acquires photographed image data of the gear 5 (step S1). The image processing unit 31 also reads out the corresponding 3D model file 361 from the 3D reference database 36 based on the gear ID of the gear 5 to be inspected, and acquires 3D model data (step S2). If a tooth surface information file 362 exists, the image processing unit 31 reads out the corresponding tooth surface information file 362 from the 3D reference database 36 based on the gear ID of the gear 5 to acquire coordinate position information of the ridgeline and angle of view information.

[0029] The image processing unit 31 generates a gear image including the target tooth surface 50 from the captured image data (step S3), and displays the gear image on a display, which is an output device. The image processing unit 31 may generate the gear image by performing filter processing such as image size adjustment and smoothing on the acquired captured image data. As a result, the gear image, i.e., an image of a portion of the gear 5 including the target tooth surface 50, is displayed on the display screen, as shown in Fig. 4. Tooth contact marks 51 are visualized on the target tooth surface 50 by the paint.

[0030] The operator sets predetermined feature points by input on the gear image displayed on the display screen. In FIG. 4 , the positions of the feature points are indicated by the tip of a drop shape containing a number. The operator can set feature points on the gear image, for example, by moving a mouse pointer operated with a mouse, which is an input device, or by touching or pressing a touch panel. The number of feature points is multiple, preferably four or more. The feature points preferably include both ends of the tip of the target tooth surface 50 in the tooth trace direction and both ends of the root of the target tooth surface 50 in the tooth trace direction. The feature points further preferably include both ends of the tip of the corresponding tooth surfaces on both sides of the target tooth surface 50 (i.e., tooth surfaces facing the same rotational direction) in the tooth trace direction and both ends of the root of the corresponding tooth surfaces on both sides of the target tooth surface 50 in the tooth trace direction. The feature points may be specified in advance, and the operator may be configured to specify the specified feature points on the gear image.

[0031] The image processing unit 31 acquires the position information of the feature points on the gear image input as described above (step S4). In this embodiment, the feature points are set by input by the operator, but the image processing unit 31 may automatically extract the feature points by image analysis. In this case, the image processing unit 31 extracts the contour of the tooth surface based on, for example, differences in shading in the gear image, and performs processing to set predetermined feature points on the contour of the tooth surface.

[0032] The image processing unit 31 uses AR (Augmented Reality) technology to generate AR composite data by superimposing the gear image on a virtual gear 52 in a three-dimensional spatial coordinate system (step S5), and displays and outputs the AR composite data on the display screen. As illustrated in FIG. 5 , the AR composite data (i.e., the AR composite image) displayed and output on the display screen is obtained by superimposing a real-world gear image on the virtual gear 52. The virtual gear 52 is a three-dimensional gear shape model generated from 3D model data. The virtual gear 52 may be a portion of the three-dimensional gear shape model including one to five teeth. Feature points corresponding to feature points of the gear image are assigned to the virtual gear 52. The feature points may be specified for the virtual gear 52 in advance, or points corresponding to the feature points of the gear image may be set after the AR composite data is generated. The image processing unit 31 maps the gear image onto the virtual gear 52 so that the feature points of the real-world gear image and the virtual gear 52 overlap. The image processing unit 31 stores coordinate position information of the ridge lines of the tooth surfaces of the virtual gear 52 onto which the real-world gear image has been superimposed in the tooth surface information file 362 of the 3D reference database 36. The image processing unit 31 also stores field of view information of the virtual gear 52 onto which the real-world gear image has been superimposed in the tooth surface information file 362 of the 3D reference database 36. Note that the AR processing method for superimposing the real-world gear image displayed on the screen onto the virtual gear 52 is not limited to the above.

[0033] The virtual gear 52 in the AR composite image is displayed, for example, as a perspective view or a contour view so that the real-world gear image (particularly the target tooth surface 50 and the tooth contact marks 51 on the target tooth surface 50) can be visually recognized. The virtual gear 52 may be able to be switched between being displayed and not displayed in the AR composite image. The image processing unit 31 can display an inspection grid 53 for tooth contact inspection on the tooth surface of the virtual gear 52 (step S6). Information for displaying the inspection grid 53 on the display screen is included in the 3D model data. The inspection grid 53 is displayed superimposed on the tooth surface of the virtual gear 52. The inspection grid 53 consists of, for example, a frame line surrounding the tooth surface of the virtual gear 52 superimposed on the target tooth surface 50, and vertical and horizontal ruled lines arranged within the frame line. The ruled lines include a center line and auxiliary lines, and the spacing between the ruled lines may be set according to the evaluation criteria. The inspection grid 53 serves as a guide for the operator to determine the position and size of the paint adhesion area on the tooth surface when visually checking it.

[0034] The operator inputs and specifies a tooth contact area 55 in the AR composite data displayed on the display screen. The tooth contact area 55 is an area in the AR composite data that corresponds to or overlaps with the tooth contact mark 51 in the real-world gear image. As illustrated in FIG. 6 , the tooth contact area 55 is specified by, for example, specifying the outline of the tooth contact mark 51 in the AR composite data. The operator inputs the positions of multiple points on the outline of the tooth contact mark 51 displayed on the gear image by, for example, moving a mouse pointer operated with a mouse, which is an input device, or by touching or pressing a touch panel. The image processing unit 31 acquires positional information in the three-dimensional coordinate system of multiple points on the outline of the tooth contact mark 51, identifies the outline of the tooth contact area 55 by connecting the multiple points with lines, and identifies the interior of the outline of the identified tooth contact area 55 as the tooth contact area 55 (step S7). The image processing unit 31 then obtains and stores the positional information in the three-dimensional coordinate system of the tooth contact area 55 (step S8). In this embodiment, the tooth contact area 55 is specified by input by the operator, but the tooth contact area 55 may also be specified automatically by the image processing unit 31. In this case, the image processing unit 31 extracts the outline of the tooth contact mark 51 on the gear image by, for example, image analysis, and specifies the inside of the extracted outline as the tooth contact area 55.

[0035] The inspection unit 32 of the processing device 3 acquires the position information of the tooth contact area 55 in the three-dimensional spatial coordinate system (step S9). The inspection unit 32 evaluates the tooth contact state using the inspection grid 53 and the position information of the tooth contact area 55 in the three-dimensional spatial coordinate system.

[0036] The inspection unit 32 reads the gear file 371 and the judgment criteria file 372 corresponding to the gear 5 to be inspected from the gear database 37 and acquires this information (Step S10). The inspection unit 32 then calculates a value for evaluating the tooth contact condition for each item in the tooth contact inspection using a given calculation formula, compares the value with the judgment criteria, and automatically evaluates the tooth contact condition (Step S11), and stores the evaluation. The evaluation of the tooth contact condition may be expressed as "good" or "fail" or in points. For example, the inspection unit 32 calculates the dimensions and area of ​​the tooth contact area 55 in the tooth trace direction and tooth depth direction based on the positional information of the inspection grid 53 and the tooth contact area 55, and compares the calculated dimensions and area with the judgment criteria to evaluate the tooth contact condition. Furthermore, for example, the inspection unit 32 calculates the position of the center of the tooth contact area 55 relative to the tooth flank in the tooth trace direction based on the positional information of the inspection grid 53 and the tooth contact area 55, and compares the calculated position with the judgment criteria to evaluate the tooth contact condition. However, the tooth contact inspection items are determined based on the requirements of the product to which the gear is applied and are not limited to the above. The inspection unit 32 may make a comprehensive pass / fail judgment based on the evaluation of a given tooth contact inspection item. Here, if the judgment criteria are combined with the gear file 371, the judgment may be made by directly superimposing the tooth contact area 55 and the position information of the tooth contact area 55 (or the shape information of the tooth contact area 55) of the judgment criteria contained in the gear file 371.

[0037] The inspection unit 32 generates and outputs inspection result information using the generated gear image, AR composite data, gear information, etc. as a result of the evaluation of the tooth contact state (step S12). The inspection result information includes, for example, the gear information, gear image, AR composite data, evaluation values ​​and judgment criteria for each item of the tooth contact inspection, and a pass / fail judgment. The inspection unit 32 can display the generated inspection result information on a display as an output device, or print it out from a printer to create an inspection report.

[0038] [Summary] The tooth contact inspection device 1 for a gear 5 according to the first item of the present disclosure includes a processing device 3, which is configured to: acquire photographed image data of the gear 5 including a target tooth surface 50 having a tooth contact mark 51 visualized by paint; generate a gear image including the target tooth surface 50 from the photographed image data; acquire 3D model data of the gear 5; generate AR composite data by superimposing the gear image on a virtual gear 52 in a three-dimensional spatial coordinate system generated from the 3D model data; and evaluate the tooth contact state based on the tooth contact area 55 corresponding to the tooth contact mark 51 in the AR composite data.

[0039] The tooth contact inspection device 1 for a gear 5 according to the second item of the present disclosure is the tooth contact inspection device 1 for a gear 5 according to the first item, further comprising an imaging device 2 that generates captured image data.

[0040] In the tooth contact inspection device 1 according to the first and second aspects, the AR synthetic data is obtained by superimposing a real-world gear image on a virtual gear 52. Visual information from the virtual gear 52 clarifies the contours of the tooth flanks, which are unclear in the real-world gear image, and the position and dimensions of the tooth contact marks 51 on the tooth flanks. Furthermore, if a portion of the tooth flank is not displayed in the gear image or if the gear tooth flank is twisted, it is difficult to accurately capture the dimensions and shape of the tooth contact marks 51 on the tooth flanks using only the photographed gear image. However, by superimposing the gear image on the virtual gear 52 as AR content and using the shape information of the virtual gear 52 to identify the shape of the tooth flank of the real-world gear, the dimensions and shape of the tooth contact marks 51 can be more accurately determined. Furthermore, the position and dimensions of the tooth contact marks 51 can be represented and measured using the three-dimensional spatial coordinate system of the virtual gear 52, improving the accuracy of measuring the position and dimensions of the tooth contact marks 51 relative to the target tooth flank 50.

[0041] A tooth contact inspection device 1 for a gear 5 according to a third item of the present disclosure is the tooth contact inspection device 1 for a gear 5 according to the first or second item, in which the processing device 3 is configured to display, in the AR composite data, a frame line surrounding the tooth surface of the virtual gear 52 overlapping with the target tooth surface 50, and an inspection grid 53 having ruled lines arranged within the frame line. The ruled lines may include a center line and auxiliary lines.

[0042] According to the tooth contact inspection device 1 configured as described above, the operator can easily visually recognize the dimensions and positions of the tooth contact marks 51 on the tooth surface from the inspection grid 53 and the tooth contact marks 51 shown in the AR composite data output as an image.

[0043] The tooth contact inspection device 1 for a gear 5 according to the fourth item of the present disclosure is the tooth contact inspection device 1 for a gear 5 according to any one of the first to third items, in which the processing device 3 defines an area in the AR composite data that overlaps with the tooth contact mark 51 as a tooth contact area 55, acquires position information of the tooth contact area 55 in a three-dimensional spatial coordinate system, and evaluates the tooth contact state based on the position information of the tooth contact area 55 in the three-dimensional spatial coordinate system.

[0044] According to the tooth contact inspection device 1 having the above configuration, the processing device 3 can inspect the tooth contact state without human judgment based on the position information of the tooth contact area 55. Therefore, stable inspection quality can be provided.

[0045] The tooth contact inspection device 1 for a gear 5 according to the fifth item of the present disclosure is the tooth contact inspection device 1 for a gear 5 according to the fourth item, in which the processing device 3 is configured to acquire positional information of a plurality of points on the contour of the tooth contact mark 51 in the AR composite data, connect the plurality of points with lines to identify the contour of the tooth contact area 55, and determine the positional information of the tooth contact area 55 from the identified contour of the tooth contact area 55.

[0046] There may be paint adhering to the tooth surface in addition to the tooth contact mark 51, and it may be cumbersome to analyze the paint adhesion state with the processing device 3 and extract the tooth contact mark 51. Even in such a case, with the tooth contact inspection device 1 configured as described above, the processing device 3 can acquire positional information of multiple points on the outline of the tooth contact mark 51 that the worker inputs while visually checking the AR composite data output as an image, thereby simplifying the processing.

[0047] The tooth contact inspection device 1 for a gear 5 according to the sixth item of the present disclosure is the tooth contact inspection device 1 for a gear 5 according to any one of the first to fifth items, wherein the processing device 3 is configured to acquire criteria information for determining the tooth contact state, and compare the tooth contact area 55 with the criteria information to automatically determine the tooth contact state.

[0048] According to the tooth contact inspection device 1 having the above-described configuration, it is possible to automatically determine whether the tooth contact state of the gear 5 is good or bad or to evaluate it.

[0049] The tooth contact inspection device 1 for a gear 5 according to the seventh item of the present disclosure is a tooth contact inspection device 1 for a gear 5 according to any one of the first to sixth items, in which the processing device 3 is configured to output inspection result information including the evaluation result of the tooth contact state and AR composite data.

[0050] According to the tooth contact inspection device 1 having the above configuration, even the creation of an inspection report can be automated. Furthermore, if the inspection result information is accumulated, it can be used to improve reproducibility and traceability.

[0051] A tooth contact inspection method for a gear 5 according to an eighth item of the present disclosure is a tooth contact inspection method for a gear 5 performed by a computer (i.e., the processing device 3), and includes: acquiring photographed image data of the gear 5 including a target tooth surface 50 having a tooth contact mark 51 visualized by paint; generating a gear image including the target tooth surface 50 from the photographed image data; acquiring 3D model data of the gear 5; generating AR composite data in which a virtual gear 52 in a three-dimensional coordinate system generated from the 3D model data is superimposed on the gear image; and evaluating the tooth contact state based on the tooth contact area 55 corresponding to the tooth contact mark 51 in the AR composite data.

[0052] According to the above-described method for inspecting tooth contact of a gear 5, the AR synthetic data is obtained by superimposing a real-world gear image on a virtual gear 52. Visual information from the virtual gear 52 clarifies the contours of the tooth flanks, which are unclear in the real-world gear image, and the position and dimensions of the tooth contact marks 51 on the tooth flanks. Furthermore, if a portion of the tooth flank is not displayed in the gear image or if the gear tooth flank is twisted, it is difficult to accurately capture the dimensions and shape of the tooth contact marks 51 on the tooth flanks using only the photographed gear image. However, by superimposing a virtual gear 52 as AR content on the gear image and using shape information from the virtual gear 52 to identify the shape of the tooth flank of the real-world gear, the dimensions and shape of the tooth contact marks 51 can be more accurately determined. Furthermore, the position and dimensions of the tooth contact marks 51 can be represented and measured using the three-dimensional spatial coordinate system of the virtual gear 52, improving the accuracy of measuring the position and dimensions of the tooth contact marks 51 relative to the target tooth flank 50.

[0053] The functions performed by the processing device 3 described herein may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuits, and / or combinations thereof, programmed to perform the described functions. Processors include transistors and other circuits and are considered circuitry or processing circuitry. A processor may also be a programmed processor that executes a program stored in memory. In this specification, a circuit, unit, or means is hardware that is programmed to perform or executes the described functions. The hardware may be any hardware disclosed herein or any hardware known to be programmed to perform or execute the described functions. When the hardware is a processor, which is considered a type of circuitry, the circuit, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0054] The foregoing discussion of the present disclosure has been presented for purposes of illustration and description and is not intended to limit the present disclosure to the form disclosed herein. For example, in the foregoing detailed description, various features of the present disclosure are grouped together in a single embodiment for the purpose of streamlining the disclosure, but some of the features may also be combined. Furthermore, the features included in the present disclosure may be combined into alternative embodiments, configurations, or aspects other than those discussed above.

[0055] 1: Tooth contact inspection device 2: Imaging device 3: Processing device 5: Gear 50: Target tooth surface 51: Tooth contact mark 52: Virtual gear 53: Inspection grid 55: Tooth contact area

Claims

1. A gear tooth contact inspection device comprising a processing device configured to: acquire photographed image data of a gear including a target tooth surface having a tooth contact mark visualized by paint; generate a gear image including the target tooth surface from the photographed image data; acquire 3D model data of the gear; generate AR composite data by superimposing the gear image on a virtual gear in a three-dimensional coordinate system generated from the 3D model data; and evaluate a tooth contact condition based on the tooth contact area corresponding to the tooth contact mark in the AR composite data.

2. The gear tooth contact inspection device according to claim 1, further comprising an imaging device that generates the photographed image data.

3. The gear tooth contact inspection device according to claim 1, wherein the processing device is configured to display, in the AR synthetic data, an inspection grid having a frame line surrounding the tooth surface of the virtual gear overlapping with the target tooth surface, and ruled lines disposed within the frame line.

4. A gear tooth contact inspection device as described in claim 1 or 3, wherein the processing device is configured to determine the area in the AR synthetic data that overlaps with the tooth contact mark as the tooth contact area, obtain position information of the tooth contact area in the three-dimensional coordinate system, and evaluate the tooth contact condition based on the position information of the tooth contact area in the three-dimensional coordinate system.

5. A gear tooth contact inspection device as described in claim 4, wherein the processing device is configured to obtain position information of a plurality of points on the contour of the tooth contact mark in the AR synthetic data, connect the plurality of points with lines to identify the contour of the tooth contact area, and obtain position information of the tooth contact area from the identified contour of the tooth contact area.

6. A gear tooth contact inspection device as set forth in claim 1, wherein the processing device is configured to acquire criteria information for determining the tooth contact state and automatically determine the tooth contact state by comparing the tooth contact area with the criteria information.

7. The gear tooth contact inspection device according to claim 1, wherein the processing device is configured to output inspection result information including the result of the evaluation of the tooth contact state and the AR composite data.

8. A gear tooth contact inspection method carried out by a computer, comprising: acquiring photographed image data of a gear including a target tooth surface having a tooth contact mark visualized with paint; acquiring 3D model data of the gear; generating a gear image including the target tooth surface from the photographed image data; generating AR composite data by superimposing the gear image on a virtual gear in a three-dimensional coordinate system generated from the 3D model data; and evaluating a tooth contact condition based on the tooth contact area corresponding to the tooth contact mark in the AR composite data.