JP2020046282A - Visual inspection device and visual inspection method - Google Patents

Abstract

To inspect the appearance of a rotary component with good accuracy that includes a concentric part finished in a convex or a concave shape concentrically on a revolving shaft and rotates around the revolving shaft.SOLUTION: The present invention rotates a rotary component around a revolving shaft relatively to a line sensor and acquires a polar coordinate image that is represented by a polar coordinate system by the line sensor; converts the polar coordinate image from the polar coordinate system to an orthogonal coordinate system and acquires an orthogonal coordinate image; detects at least some edges of the concentric part from the orthogonal coordinate image; executes circle fitting on the position information of these edges; calculates the diameter of a circle corresponding to the concentric part; and inspects the acceptability of the concentric part on the basis of the diameter.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a visual inspection technique for inspecting the appearance of a rotating part such as a gear or a flange joint that rotates around a rotating axis, and particularly to a finishing of a convex or concave shape concentric with the rotating axis in a rotating part. The present invention relates to a technique for inspecting concentric parts.

  In order to automatically perform the appearance inspection of rotating parts such as gears and flange joints, it is possible to perform the appearance inspection of rotating parts using a measurement technique using a digital camera as described in Patent Document 1, for example. Are being considered. In the measurement technique described in Patent Document 1, a digital camera captures an image of a rotating component to be inspected, acquires a two-dimensional image, and measures the outer dimensions of the rotating component from image data of the two-dimensional image. Then, it can be determined from the measurement result whether the rotating component is a non-defective product.

Patent No. 3668653 JP 2011-256974 A

  Utilizing the technology described in Patent Document 1 described above, the size and shape of a rotating component can be measured. More specifically, it is required to inspect whether or not concentric portions are formed within a range of tolerance in a rotating component. Here, the “concentric portion” means a portion which is finished concentrically with respect to the rotation axis of the rotating component in a convex or concave shape, and is provided on a gear as described in Patent Document 2, for example. The set cone corresponds to an example of the “concentric portion finished in a convex shape” of the present invention, and the sinking groove corresponds to an example of the “concentric portion finished in a concave shape” of the present invention. In the following description, the above-described inspection for the concentric portion is referred to as “concentric portion inspection”.

  In order to accurately inspect a rotating component including the concentric portion inspection, it is necessary to determine the size of the concentric portion, that is, the diameter of the concentric portion. However, there is no specific description about that in Patent Document 1. Further, there has not been a visual inspection technique for calculating the diameter of the concentric portion and inspecting the concentric portion.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an accurate inspection of the appearance of a rotating component having a concentric portion finished in a convex or concave shape concentrically with respect to a rotating shaft and rotating around the rotating shaft. It is an object of the present invention to provide a visual inspection device and a visual inspection method that can perform the above.

  One embodiment of the present invention is an appearance inspection device that inspects the appearance of a rotating component, which has a concentric portion finished in a convex or concave shape concentrically with respect to a rotation axis and rotates around the rotation axis, A line sensor having one end positioned on the extension of the rotation axis and the other end extending in a direction orthogonal to the rotation axis to capture a line image of the rotating component; A rotating unit that relatively rotates the rotating component about a rotation axis, and a polar coordinate image represented by a polar coordinate system captured by the line sensor while the rotating component relatively rotates with respect to the line sensor. A storage unit for storing, a coordinate conversion unit for converting the polar coordinate image stored in the storage unit from a polar coordinate system to a rectangular coordinate system to obtain a rectangular coordinate image, and the concentricity from the rectangular coordinate image. An edge detecting unit that detects at least a part of the edge of the edge, and performing a circle fitting on the position information of the edge detected by the edge detecting unit, and calculating a diameter of a circle corresponding to the concentric portion And a testing unit for checking the quality of the concentric portion based on the diameter calculated by the diameter calculating unit.

  Another aspect of the present invention is an appearance inspection method for inspecting the appearance of a rotating component, which has a concentric portion finished in a convex or concave shape concentrically with respect to a rotation axis and rotates around the rotation axis. A line sensor that has one end positioned on an extension of the rotation axis and the other end extends in a direction orthogonal to the rotation axis and captures a line image of the rotation component. A step of relatively rotating the rotating part around to obtain a polar coordinate image represented by a polar coordinate system by the line sensor; and obtaining the rectangular coordinate image by converting the polar coordinate image from a polar coordinate system to a rectangular coordinate system. Detecting at least a part of the edge of the concentric portion from the rectangular coordinate image; and performing circle fitting on the position information of the edge detected by the edge detection unit. Run, calculating a diameter of a circle corresponding to the concentric portion is characterized by comprising a step of inspecting the quality of the concentric portion based on the calculated diameters.

  In the invention configured as described above, the polar coordinate image of the rotating component having the concentric portion is converted into the rectangular coordinate image. Then, at least a part of the edge of the concentric portion is detected from the rectangular coordinate image. A circle fitting is performed on the position information of the edge to calculate a diameter of a circle corresponding to the concentric portion. Further, the quality of the concentric portion is checked based on the calculated diameter.

  As described above, the quality of the concentric portion of the rotating component, which has not been conventionally inspected, is inspected, and the appearance of the rotating component can be inspected with high accuracy.

It is a figure showing one embodiment of a visual inspection device concerning the present invention. FIG. 2 is a block diagram illustrating an electrical configuration of the appearance inspection device illustrated in FIG. 1. FIG. 3 is a perspective view illustrating a configuration of a work holding unit. 3 is a flowchart showing a work inspection operation by the visual inspection device shown in FIG. 1. It is a figure for explaining diameter calculation operation of a concentric part.

  FIG. 1 is a diagram showing an overall configuration of a first embodiment of a visual inspection apparatus according to the present invention. FIG. 2 is a block diagram showing an electrical configuration of the appearance inspection apparatus shown in FIG. The appearance inspection apparatus 100 is an apparatus for inspecting the appearance of rotating parts (hereinafter, referred to as “work W”) such as gears and flange joints that rotate about a rotation axis AX, and includes a loading unit 1 and a work holding unit 2. , An imaging unit 3, an unloading unit 4 and a control unit 5. In this case, the workpiece W is a rotating part having a concentric part Wb concentric with the rotation axis AX on the shaft part Wa on the shaft part Wa, as shown in FIG. It is formed by a casting process. After the parts are manufactured, the work W is transferred to the loading unit 1 by an external transfer robot or an operator.

  The loading unit 1 is provided with a work accommodating section (not shown) such as a table and a stocker. When the work W is temporarily accommodated in the work accommodating portion by an external transfer robot or the like, the work detection sensor 11 (FIG. 2) provided in the work accommodating portion detects the work W, and a signal to that effect is sent to the apparatus. It is transmitted to the control unit 5 that controls the whole. The loading unit 1 is provided with a loader 12 (FIG. 2), which receives an uninspected work W stored in a work storage unit in response to an operation command from the control unit 5, and Transport to

  FIG. 3 is a perspective view showing the configuration of the work holding unit. The work holding unit 2 is equipped with holding tables 21A and 21B for holding the work W transported by the loader 12. These holding tables 21A and 21B have the same configuration, and can hold and hold a part of the shaft Wa of the work W in a posture where the concentric portion Wb is in a horizontal state. Hereinafter, the configuration of the holding table 21A will be described with reference to FIG. 3, while the holding table 21B has the same configuration as the holding table 21A.

  In the holding table 21A, as shown in FIG. 3, a chuck mechanism 22, a horizontal positioning mechanism 23, a rotating mechanism 24, and a vertical positioning mechanism 25 are vertically stacked. The chuck mechanism 22 includes movable members 221 to 223 that are substantially L-shaped in a side view, and a moving unit 224 that moves the movable members 221 to 223 in a radial manner in response to a movement command from the control unit 5. ing. A projecting member 225 protrudes from the upper end surface of each of the movable members 221 to 223, and the upper end surface and the projecting member 225 can be engaged with the step portion of the shaft Wa. For this reason, the moving unit 224 moves the movable members 221 to 223 closer to each other in response to the gripping command from the control unit 5 so that the center axis (not shown) of the chuck mechanism 22 and the axis of the shaft Wa are aligned. While holding the work W, On the other hand, the moving unit 224 moves the movable members 221 to 223 away from each other in response to a release command from the control unit 5, so that the loading of the untested work W by the loading unit 1 and the inspection of the inspected work W by the unloading unit 4 are performed. Unloading can be performed.

  The chuck mechanism 22 configured as described above is supported by the horizontal positioning mechanism 23. The horizontal positioning mechanism 23 has a so-called XY table that moves in directions orthogonal to each other in the horizontal direction. For this reason, the XY table is driven in response to the movement command from the control unit 5, and the chuck mechanism 22 can be positioned with high accuracy on a horizontal plane. As the XY table, a combination of a motor and a ball screw mechanism, a combination of two linear motors orthogonal to each other in a horizontal direction, and the like can be used.

  The rotation mechanism 24 has a motor 241. A rotating shaft (not shown) of the motor 241 extends vertically upward, and a horizontal positioning mechanism 23 is connected to an upper end thereof. For this reason, when a rotation command is given from the control unit 5, the motor 241 operates and the horizontal positioning mechanism 23, the chuck mechanism 22, and the work W gripped by the chuck mechanism 22 around the rotation axis (not shown) of the motor 241. Are rotated integrally.

  Here, in the present embodiment, the horizontal positioning mechanism 23 is provided between the chuck mechanism 22 and the rotation mechanism 24, but the technical significance is that the center axis of the chuck mechanism 22, the work W held by the chuck mechanism 22. The horizontal positioning mechanism 23 makes it possible to adjust the relative positional relationship between the rotation symmetry axis (rotation axis AX) of the concentric portion Wb and the rotation axis of the motor 241. In other words, by aligning the center axis of the chuck mechanism 22 with the rotation axis of the motor 241, the work W gripped by the chuck mechanism 22 can be rotated around the shaft Wa. However, when the rotation axis AX of the workpiece W is out of the desired position, the motor 241 is misaligned, and the concentric portion Wb rotates eccentrically. Therefore, by providing the horizontal positioning mechanism 23 and driving it so as to correct the shift amount and the shift direction, the rotation axis AX of the work W and the rotation axis of the motor 241 can be matched. Thus, the image of the work W by the imaging unit 3 can be captured with high accuracy, and the inspection accuracy of the work W can be improved.

  The vertical positioning mechanism 25 includes a holding plate 251 for holding the motor 241, a base plate 252 disposed below the motor 241, four connection pins 253 for connecting the holding plate 251 and the base plate 252, and a base plate 252. And an elevating part 254 for elevating and lowering in the direction. The elevating unit 254 moves the rotating mechanism 24, the horizontal positioning mechanism 23, and the chuck mechanism 22 in the vertical direction integrally by moving the base plate 252 up and down in response to an elevating command from the control unit 5, and a pre-alignment position described next. The height position of the work W can be optimized at the PA and the inspection position PI.

  As shown in FIG. 3, the holding tables 21A and 21B configured as described above are fixed on the support plate 261 with a predetermined distance therebetween. Further, the support plate 261 is supported by the turning drive unit 262 at an intermediate position between the holding tables 21A and 21B. The turning drive unit 262 is capable of turning the support plate 261 by 180 ° about a turning axis AX1 extending in the vertical direction in response to a turning command from the control unit 5, and as shown in FIG. It is possible to switch between a first position located at the pre-alignment position PA and the inspection position PI, and a second position at which the holding tables 21A and 21B are located at the inspection position PI and the pre-alignment position PA, respectively. For example, in parallel with performing the pre-alignment process and the concentric portion inspection on the work W held on the holding table 21A located at the pre-alignment position PA, the turning drive unit 262 switches from the first position to the second position. As a result, the holding table 21A shifts from the pre-alignment position PA to the inspection position PI, and the work W that has completed the pre-alignment processing and the concentric inspection can be positioned at the inspection position PI. After the inspection of the work W is completed, the holding table 21A is shifted from the inspection position PI to the pre-alignment position PA by turning in the reverse direction, and the inspection-processed work W is positioned at the pre-alignment position PA. Can be. As described above, in the present embodiment, the position switching mechanism 26 that switches the position of the work W by the support plate 261 and the turning drive unit 262 is configured.

  The pre-alignment position PA is a position where the pre-alignment processing and the concentric inspection are performed as described above, and the line sensor 27 is disposed above the holding table 21A (or 21B) positioned at the pre-alignment position PA. The line sensor 27 is disposed on the opposite side of the motor 241 with respect to the work W, that is, on the upper side of the work W as shown in FIG. The line sensor 27 has one end located on an extension of the rotation axis AX and the other end extending in a horizontal direction orthogonal to the rotation axis AX, and is arranged in a radial direction with respect to the rotation axis AX of the workpiece W. It has a linear sensing area 271 extending outward. By picking up an image of the work W in the sensing area 271, a line image of the work W can be obtained. Therefore, the work W can be imaged from above by the sensing area 271 while rotating the work W. By rotating the work W at least once, an image including the donut-shaped plane of the concentric portion Wb can be obtained. .

  Although not shown in FIG. 3, the line sensor illuminating unit 28 (for illuminating the work W held on the holding table 21A (or 21B) and performing the alignment process and the concentric inspection properly is provided. FIG. 2) is provided. Therefore, the work W can be imaged by the line sensor 27 while the work W is rotated by the rotation mechanism 24 and the work W is illuminated by the line sensor illumination unit 28. Then, the image data of the work W is sent to the control unit 5, and a concentric inspection is performed as described later in detail, and the misalignment is corrected so that the rotation axis AX of the work W and the rotation axis of the motor 241 are aligned. Matching, that is, pre-alignment processing is executed.

  On the other hand, the inspection position PI is a position where the inspection processing is performed, and the imaging unit 3 is disposed above the holding table 21A (or 21B) positioned at the inspection position PI. At the inspection position PI, the work W can be imaged by the imaging unit 3 while rotating the work W in a state where the rotation axis AX of the work W and the rotation axis of the motor 241 coincide with each other. Then, the image data of the work W is sent to the control unit 5, and an inspection process for inspecting the work W for the presence or absence of a flaw or a defect is performed.

  This imaging unit 3 has a plurality of inspection cameras 31 and a plurality of inspection illumination units 32, as shown in FIG. In the imaging unit 3, a plurality of inspection illumination units 32 are arranged so as to illuminate the work W held on the holding table 21A (or 21B) positioned at the inspection position PI from various directions. The rotating mechanism 24 rotates the workpiece W, and the inspection illumination unit 32 illuminates the workpiece W, so that the inspection camera 31 can image the workpiece W from various directions. The plurality of pieces of image data are sent to the control unit 5, and the control unit 5 performs inspection of the work W.

  The holding table 21A (or 21B) holding the work W thus inspected is shifted from the inspection position PI to the pre-alignment position PA by the position switching mechanism 26 as described above. Then, the unloaded unit 4 unloads the inspected work W from the holding table 21A (or 21B). The unloading unit 4 is basically the same as the loading unit 1. That is, the unloading unit 4 includes a work storage unit (not shown) for temporarily storing the inspected work W, a work detection sensor 41 (FIG. 2), and an unloader 42 (FIG. 2). In response to the operation command from the work 5, the inspected work W is transported from the holding table 21A (or 21B) to the work storage unit.

  As shown in FIG. 2, the control unit 5 includes a well-known CPU (Central Processing Unit) for executing a logical operation, a ROM (Read Only Memory) for storing initial settings and the like, and temporarily stores various data during operation of the apparatus. It is composed of a RAM (Random Access Memory) and the like for temporarily storing. The control unit 5 functionally includes an arithmetic processing unit 51, a storage unit 52, a drive control unit 53, an external input / output unit 54, an image processing unit 55, and an illumination control unit 56.

  The drive control unit 53 controls the drive of a drive mechanism provided in each unit of the apparatus, for example, the loader 12, the chuck mechanism 22, and the like. The external input / output unit 54 inputs signals from various sensors provided in each unit of the device, and outputs signals to various actuators and the like provided in each unit of the device. The image processing unit 55 captures image data from the line sensor 27 and the inspection camera 31 and performs image processing such as binarization. The lighting control unit 56 controls turning on and off of the line sensor lighting unit 28 and the inspection lighting unit 32, and the like.

  The arithmetic processing unit 51 has an arithmetic function, and controls the drive control unit 53, the image processing unit 55, the illumination control unit 56, and the like according to a program 521 stored in the storage unit 52, and will be described next. Perform a series of processing. As a result, while the work W rotates around the rotation axis AX, a polar coordinate image 522 represented by a polar coordinate system is captured by the line sensor 27 and stored in the storage unit 52. The arithmetic processing unit 51 performs coordinate conversion, edge detection, diameter calculation of the concentric portion Wb, and pass / fail inspection based on the polar coordinate image 522. The coordinate conversion unit 511, the edge detection unit 512, the diameter calculation unit 513, and the inspection It functions as the unit 514. Further, the storage unit 52 stores a dimensional tolerance 523 of the work W as determination information for performing the inspection by the inspection unit 514.

  Reference numeral 6 in FIG. 2 denotes a display unit functioning as an interface with the operator, which is connected to the control unit 5 and has a function of displaying the operation state of the visual inspection device 100 and a touch panel constituted by a touch panel. It also has a function as an input terminal that accepts input. Further, the present invention is not limited to this configuration, and a display device for displaying an operation state and an input terminal such as a keyboard and a mouse may be employed.

  FIG. 4 is a flowchart showing a work inspection operation by the visual inspection apparatus shown in FIG. FIG. 5 is a diagram schematically showing the concentric portion inspection operation. In FIG. 5, in the captured image, a portion indicating the upper surface Wb1 (see FIG. 1) of the concentric portion Wb is clearly distinguished from a portion indicating the inclined surface Wb2 (see FIG. 1) spreading like a skirt. To this end, hatching is applied to the image portion corresponding to the upper surface Wb1, while dots are added to the image portion corresponding to the inclined surface Wb2.

  In the appearance inspection apparatus 100, the arithmetic processing unit 51 controls each unit of the apparatus according to the inspection program stored in the storage unit 52 of the control unit 5 in advance, and executes the following operation. Here, various operations performed on one work W while focusing on the work W will be described with reference to FIGS. 4 and 5. The control unit 5 determines that the work W does not exist on the holding table 21A located at the pre-alignment position PA, and that the work W which has not been inspected by the work detection sensor 11 is housed in the work housing part of the loading unit 1. Is confirmed, loading of the work W onto the holding table 21A is started (step S1). In this loading step, the loader 12 grips the uninspected work W in the work accommodating portion and transports the work W from the loading unit 1 to the holding table 21A. In the present embodiment, in order to smoothly perform the loading process and the subsequent misalignment detection process, the horizontal positioning mechanism 23 and the center axis of the chuck mechanism 22 and the motor 241 are used by the horizontal positioning mechanism 23 before the work W is transported to the holding table 21A. And the three movable members 221 to 223 are separated from each other to prepare for receiving the work W.

  When the work W is conveyed to the holding table 21A by the loader 12, the chuck mechanism 22 moves the three movable members 221 to 223 closer to each other as described above to sandwich a part of the shaft Wa of the work W. The work W is gripped. More specifically, during the loading operation, the movable members 221 to 223 move close to each other, and the upper end surfaces of the movable members 221 to 223 and the projecting members 225 engage with the step portions of the shaft Wa, and The workpiece W is held while the center axis and the axis of the axis Wa are aligned. Thus, the loading step is completed. At this point, the rotation axis of the motor 241, the center axis of the chuck mechanism 22, and the axis of the shaft Wa are aligned. However, in the work W manufactured by forging or casting, for example, the rotation axis AX of the work W may be displaced from the axis of the shaft Wa, and the work W may be misaligned with respect to the motor 241.

  Therefore, in the present embodiment, the uninspected work W is illuminated by the line sensor illumination unit 28 (FIG. 2), and the concentric part Wb is sensed by the line sensor 27 while the uninspected work W is rotated at least once by the motor 241 of the holding table 21A. Is captured from above, and the polar coordinate image 522 of the work W is stored in the storage unit 52 (step S2).

  After the completion of the imaging, the rotation drive unit 262 switches the first position to the second position. That is, the turning drive unit 262 turns the support plate 261 by 180 ° about the turning axis AX1, whereby the holding table 21A holding the untested work W moves from the pre-alignment position PA to the inspection position PI and the elevating unit 254. The work W is moved to a height position where the image can be imaged by the imaging unit 3 (step S3).

  Further, in the present embodiment, in parallel with the movement, the image data of the polar coordinate image 522 of the work W is read from the storage unit 52, and the misalignment of the work W with respect to the rotation mechanism 24 (motor 241) is detected (step S4). Subsequently, the misalignment of the holding table 21A is corrected (step S5). Further, in the present embodiment, not only the misalignment detection and misalignment correction, but also the diameter of the concentric portion Wb is detected (Step S6), and the quality of the concentric portion Wb is inspected based on the detection result (Step S7). The concentric inspection operation will be described later in detail.

  In the misalignment correction in step S5, the chuck mechanism 22 is moved by the horizontal positioning mechanism 23 so as to eliminate the misalignment detected in step S4. As a result, the rotation axis AX of the work W and the rotation axis of the motor 241 coincide with each other at or before or after the holding table 21A reaches the inspection position PI, and the work imaging step (step S8) can be started immediately.

  In step S8, the rotation mechanism 24 of the holding table 21A positioned at the inspection position PI operates to start rotating the work. At this time, the work W held on the holding table 21A is in a so-called centered state that has been subjected to the above-described misalignment correction, and rotates around the rotation axis AX. In addition, the plurality of inspection illumination units 32 are turned on in response to the rotation, and illuminate the rotating workpiece W from a plurality of directions. Here, the inspection lighting unit 32 is turned on after the work is rotated, but the lighting timing is not limited to this, and the lighting of the inspection lighting unit 32 is started at the same time as the start of rotation or before the start of rotation. Is also good.

  While the work W is being rotated and illuminated in this way, the plurality of inspection cameras 31 image the work W from various directions, and image data of images of the work W from multiple directions (hereinafter, referred to as “work images”). Is transmitted to the control unit 5. On the other hand, the control unit 5 stores the work image in the storage unit 52, and performs the inspection of the work W (excluding the inspection of the concentric portion Wb) at the following timing based on the image data of the work image.

  After such image acquisition, the work rotation is stopped in the holding table 21A, and the inspection illumination unit 32 is turned off in the imaging unit 3. Further, the turning drive unit 262 turns the support plate 261 by 180 ° inversion about the turning axis AX1, whereby the holding table 21A moves from the inspection position PI to the pre-alignment position PA while holding the inspected work W, and moves up and down. The work W is moved to the original height position by the part 254 (step S9). In parallel with the movement of the work W, the control unit 5 reads out the image data of the work image from the storage unit 52, determines whether the work W has a flaw or a defect on the basis of the work image, and holds it. A work inspection is performed on the work W held in the table 21A (step S10).

  The work W returned to the pre-alignment position PA is gripped by the unloader 42, and is then transferred from the holding table 21A to the unloader 42 by releasing the gripping by the movable members 221 to 223. Subsequently, the unloader 42 conveys the work W to the unloading unit 4, and conveys the work W to a work storage unit (not shown) (step S11). The above-described series of steps (steps S1 to S11) are alternately repeated by the holding tables 21A and 21B.

  Next, the concentric diameter calculation step (step S6) executed in the present embodiment will be described in detail with reference to FIG. FIG. 5 is a diagram showing a process of calculating the diameter of the concentric portion, which is performed by the visual inspection apparatus shown in FIG. In the figure, while the operation flowchart of the diameter calculation process is shown in the center, the operations of steps S61, S63, and S65 are schematically shown in the left, and steps S62, S64, and S66 are shown in the right. The operation is shown schematically. The arithmetic processing unit 51 controls each unit of the device according to the program 521 stored in the storage unit 52 to execute the operation shown in FIG. Hereinafter, the contents will be described in association with the operation flowchart in FIG. 5 and the schematic diagram.

  In the step of calculating the diameter of the concentric portion Wb (step S6), the image data of the polar coordinate image 522 of the work W captured in step S2 is read out from the storage unit 52 and is developed in the RAM of the arithmetic processing unit 51 (step S61). ). The arithmetic processing unit 51 executes a conversion process for converting the image data thus obtained from the polar coordinate system to the rectangular coordinate system, and converts the polar coordinate image 522 into the rectangular coordinate image G (step S62). As the conversion processing itself, a known one can be used. The orthogonal coordinate image G obtained by the conversion processing includes an upper surface image obtained by imaging the upper surface Wb1 of the concentric portion Wb as shown in FIG. G1 (hatched area) and an inclined plane image G2 (dot applied area) obtained by imaging the inclined plane Wb2 are included.

  Here, in order to perform the quality inspection of the concentric portion Wb, the rectangular coordinate image G can be used as it is, or the inclined surface image G2 can be used, but the shape and dimensions of the concentric portion Wb are obtained in the upper surface image G1. , The edge information of the concentric portion Wb is clearly shown. Therefore, in the present embodiment, the upper surface image g1 is detected by performing binarization processing on the image data of the rectangular coordinate image G (step S63). By removing the inclined surface image G2 in this manner, edge information included in the inclined surface image G2 is excluded, and the range of edge extraction is limited. As a result, the binarized image g acquired in step S63 includes only the image g1 corresponding to the upper surface Wb1 of the concentric portion Wb.

  Next, the arithmetic processing unit 51 performs edge detection from the image g1 (step S64). In the present embodiment, in order to remove the influence of noise at the time of edge detection processing and to extract a desired edge, that is, to extract a circular edge EG indicating the shape of the concentric portion Wb, the arithmetic processing unit 51 uses the binarized image. A plurality of pieces of data corresponding to the edge detection area ED are extracted from the image data of g. In FIG. 5, only one of the plurality of edge detection areas ED is indicated by a broken line. Although the number of extractions is arbitrary, in the present embodiment, the number is set to a number corresponding to about １ ／ of the edge EG.

  Then, the arithmetic processing unit 51 detects an edge of the concentric portion Wb based on the image data of each edge detection area ED (step S65). In this embodiment, as shown by the bold line in the figure, edge detection is performed on each of about one-third of the edge of the concentric portion Wb to obtain position information of each edge detection area ED. Further, the arithmetic processing unit 51 obtains a true circle G3 by a circle fitting process based on these edge detection results, that is, the position information of each edge, and draws the true circle G3 on the orthogonal coordinate image G (step S66). Since the circle fitting itself is known, the description of the circle fitting process is omitted in this specification.

  Further, the arithmetic processing unit 51 calculates the diameter φ of the perfect circle G3 thus drawn as the outer diameter of the concentric portion Wb (step S67). When the diameter calculation process of the concentric portion Wb (step S6) is completed, the arithmetic processing unit 51 calculates the diameter φ calculated in step S6 by using the dimensional tolerance of the work W stored in the storage unit 52, as shown in FIG. Inspection is performed in comparison with 523 (step S7). More specifically, the arithmetic processing unit 51 determines that the concentric portion Wb is good when the calculated diameter φ is within the range of the dimensional tolerance 523 stored in the storage unit 52, and determines that the concentric portion Wb is good. Is determined to be defective.

  As described above, according to the present embodiment, the polar coordinate image 522 of the work W having the concentric portion Wb is converted into the rectangular coordinate image G, and at least a part of the edge of the concentric portion Wb is detected from the rectangular coordinate image G, The diameter of the circle corresponding to the concentric portion Wb is calculated by the circle fitting process. Then, the quality of the concentric portion Wb is inspected based on the calculated diameter. As described above, the concentric portion Wb which has been conventionally excluded from the inspection target can also be inspected, and the appearance of the work W can be inspected with high accuracy.

  In the above embodiment, the position information of the edge is obtained for about one third of the edge EG, and a circle fitting process is performed on the edge position information to calculate the diameter φ of the circle corresponding to the concentric portion Wb. Therefore, the time required for the inspection can be reduced as compared with the case where the position information of the edge EG is obtained for the entire circumference of the edge EG. The range of the position information of the edge EG is not limited to about １ ／ of the edge EG, but may be, for example, about １ ／. Of course, the entire circumference of the edge EG may be used.

  As described above, in the embodiment described above, the concentric portion Wb finished in a cone shape corresponds to an example of the “concentric portion finished in a convex shape” of the present invention, and the workpiece W having the concentric portion Wb is a “rotating component” of the present invention. ". In addition, the rotation mechanism 24 corresponds to an example of the “rotation unit” of the present invention.

  The present invention is not limited to the above-described embodiment, and various changes other than those described above can be made without departing from the gist of the present invention. For example, in the above embodiment, the line sensor 27 is used for both the detection of the misalignment and the inspection of the concentric portion Wb. However, a dedicated line sensor for inspecting the concentric portion Wb may be provided.

  In the above embodiment, the polar coordinate image 522 of the work W is acquired by rotating the work W with the line sensor 27 fixed. However, one end of the line sensor 27 is rotated with the work W fixed. The polar coordinate image 522 may be obtained by rotating the line sensor 27 as a center. Further, the work W and the line sensor 27 may be rotated together. In short, what is necessary is to rotate the work W around the rotation axis AX relative to the line sensor 27 and obtain the polar coordinate image 522 of the work W.

  Further, in the above embodiment, the present invention is applied to the appearance inspection device 100 that performs the misalignment detection and the misalignment correction, but the present invention may be applied to the appearance inspection device that does not perform these. it can.

  Further, in the above embodiment, the present invention is applied to the appearance inspection device 100 for inspecting the work W having the concentric portion Wb finished in a convex shape. The present invention can be applied to a visual inspection device for inspecting a gear having the same. Here, the “sinking groove” corresponds to an example of the “concentric portion finished in a concave shape” of the present invention. Of course, the present invention can be applied to a visual inspection device that inspects a rotating component having both a concentric portion finished in a convex shape and a concentric portion finished in a concave shape.

  INDUSTRIAL APPLICABILITY The present invention can be applied to all appearance inspection techniques for inspecting the appearance of rotating parts such as gears and flange joints that rotate around a rotation axis.

24 ... Rotating mechanism (rotating part)
27 line sensor 51 arithmetic processing unit 52 storage unit 100 visual inspection device 511 coordinate conversion unit 512 edge detection unit 513 diameter calculation unit 514 inspection unit 522 polar coordinate image 523 dimensional tolerance AX rotary axis G ... Rectangular coordinate image G3 ... Perfect circle ED ... Edge detection area EG ... Edge W ... Work g ... Binary image φ ... Diameter

Claims (5)

An appearance inspection device that inspects the appearance of a rotating component, which has a concentric portion finished in a convex or concave shape concentrically with respect to the rotation axis and rotates around the rotation axis,
A line sensor that has one end located on an extension of the rotation axis and the other end extends in a direction orthogonal to the rotation axis and captures a line image of the rotating component,
A rotating unit that relatively rotates the rotating component around the rotation axis with respect to the line sensor,
A storage unit that stores a polar coordinate image represented by a polar coordinate system captured by the line sensor while the rotating component relatively rotates with respect to the line sensor,
A coordinate conversion unit that converts the polar coordinate image stored in the storage unit from a polar coordinate system to a rectangular coordinate system to obtain a rectangular coordinate image,
An edge detection unit that detects at least a part of the edge of the concentric portion from the rectangular coordinate image,
A diameter calculation unit that performs a circle fitting on the position information of the edge detected by the edge detection unit, and calculates a diameter of a circle corresponding to the concentric portion,
An inspection unit for inspecting the concentric portion based on the diameter calculated by the diameter calculation unit. The visual inspection device according to claim 1,
The inspection unit, when the diameter calculated by the diameter calculation unit is within the range of the dimensional tolerance stored in the storage unit, the concentric portion is good, when the diameter exceeds the range of the dimensional tolerance An appearance inspection device that determines that the concentric portion is defective. The appearance inspection device according to claim 1 or 2,
An appearance inspection device in which the rotating unit rotates the rotating component at least once. The visual inspection device according to claim 1, wherein:
The edge detection unit detects a plurality of different edge detection regions among the edges of the concentric portion,
The visual inspection device, wherein the diameter calculation unit performs a circle fitting on the position information of the edge included in each edge detection area to calculate a diameter of the circle. An appearance inspection method for inspecting the appearance of a rotating component, which has a concentric portion finished in a convex or concave shape concentrically with respect to a rotation axis and rotates around the rotation axis,
One end is located on the extension of the rotation axis and the other end is extended in a direction orthogonal to the rotation axis, and a line sensor that captures a line image of the rotating component is provided around the rotation axis. A step of relatively rotating a rotating component to obtain a polar coordinate image represented in a polar coordinate system by the line sensor,
Converting the polar coordinate image from a polar coordinate system to a rectangular coordinate system to obtain a rectangular coordinate image,
Detecting at least a part of the edge of the concentric portion from the rectangular coordinate image,
Performing a circle fitting on the position information of the edge detected by an edge detection unit, and calculating a diameter of a circle corresponding to the concentric part;
Inspecting the quality of the concentric portion based on the calculated diameter.

Images