Apparatus for visual inspection of rotating articles, and method for visual inspection of rotating articles

Abstract

The present invention aims to provide a rotating body article visual inspection device and a rotating body article visual inspection method that can improve inspection accuracy and shorten cycle time to increase the time efficiency of inspection. [Solution] The O-ring appearance inspection device 1 of the present invention is an appearance inspection device for inspecting the appearance of an O-ring K, comprising: a plurality of line sensor cameras 20 whose positions and orientations are set in advance and which image the O-ring K; and a holding device 10 which holds the O-ring K and has a head portion 14 that is rotatable around an axis C1, wherein the holding device 10 sequentially moves the O-ring K to a plurality of imaging positions P corresponding to each of the plurality of line sensor cameras 20, and rotates the head portion 14 around the axis C1 at the imaging positions P to rotate the O-ring K in the circumferential direction.

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for inspecting the appearance of a rotating body article such as an O-ring.

Background Art

[0002] Conventionally, various types of articles (rotating body articles) formed in the shape of a rotating body, such as an annular shape, a spherical shape, and a conical shape, have been provided. Also, there is a desire to perform an appearance inspection of a rotating body article with high accuracy. For example, an O-ring can be cited as a rotating body article formed in an annular shape. Conventionally, O-rings have been used in the sealing portions of various devices. In recent years, there are cases where higher airtightness is required for O-rings, and for this reason, O-rings having a surface finished to a small surface roughness and a mirror-like surface (mirror-like O-rings) have been provided. Also, in the case of a mirror-like O-ring, since a high degree of sealing performance is required, even a shallow dent or scratch becomes a quality problem. Therefore, in recent years, there has been a demand for an appearance inspection device capable of detecting extremely shallow dents, scratches, abrasions, etc. present on the surface of such a mirror-like O-ring.

[0003] The following Patent Document 1 discloses an appearance inspection device capable of detecting defects such as shallow dents and scratches present on the surface of such a mirror-like O-ring. In the appearance inspection device of Patent Document 1, the configuration is such that illumination light is irradiated onto the O-ring and the O-ring is imaged from the same direction as the irradiation direction of the illumination light. In the appearance inspection device of Patent Document 1, when the surface of the O-ring is normal, most of the illumination light is specularly reflected, while when there are defective portions such as dents and scratches on the surface of the O-ring, the illumination light is diffusely reflected at this defective portion and the light does not enter the line sensor camera. Thereby, the appearance inspection device of Patent Document 1 can detect defects such as shallow dents and scratches present on the surface of the mirror-like O-ring.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-40819 [Overview of the project] [Problems that the invention aims to solve]

[0005] In the visual inspection apparatus described in Patent Document 1, the entire surface of an O-ring is inspected by imaging different parts of the O-ring's surface multiple times. Therefore, to complete the visual inspection of a single O-ring, the O-ring is rotated circumferentially while being held at the imaging position, then tilted to image a different part radially, and then rotated circumferentially again. This process is repeated multiple times. Consequently, completing the visual inspection of a single O-ring takes time because it requires adjusting the angle of the holding device to image different parts of the O-ring and rotating the O-ring at each angle. On the other hand, there is a desire to shorten the cycle time and improve the time efficiency of the inspection.

[0006] Furthermore, in the visual inspection of rotating objects such as O-rings, the rotating object is rotated circumferentially in front of the line sensor camera to image the radial portion over its entire circumference. If the orientation of the line sensor camera deviates from the set angle when the rotating object is rotated, the portion of the rotating object being imaged will be misaligned, which may lead to inspection defects. Therefore, in order to improve inspection accuracy, it is necessary to suppress deviations in the orientation of the line sensor camera when the rotating object is rotated and imaged.

[0007] Therefore, the present invention aims to provide a rotating body article visual inspection device and a rotating body article visual inspection method that can improve inspection accuracy and shorten cycle time to increase the time efficiency of inspection. [Means for solving the problem]

[0008] Here, the inventors of the present invention first considered a configuration in which a supplied rotating object is picked up using a robotic arm or the like, and then imaged in front of a line sensor camera while changing the angle of the rotating object. However, when adjusting the angle of the tip (head) of the robotic arm to match the set angle, it is necessary to adjust multiple axes of the robotic arm, which takes time for the series of operations. In addition, in the visual inspection of a rotating object, it is necessary to image the surface by dividing it into multiple radially different parts, and the adjustment of each angle is critical, making it difficult for a robotic arm to easily maintain the accuracy of the set angle and position.

[0009] Incidentally, in visual inspection devices for rotating articles, it has become common practice to minimize the number of line sensor cameras, lighting devices, etc., and under this common practice, the question of how to perform visual inspection has been considered. This conventional practice in this field is evident from the fact that even in Patent Document 1, inspection is performed on the premise of using only one line sensor camera. The inventor of the present application has shifted from this common practice and deliberately considered a configuration that uses multiple line sensor cameras. Specifically, the inventor considered a configuration in which multiple line sensor cameras are set to be oriented in advance to image multiple radial parts of a rotating article.

[0010] As a result, we have found that by rapidly moving a rotating object between line sensor cameras and imaging the rotating object at each imaging position, it is possible to achieve both a reduction in cycle time and an improvement in inspection accuracy. Reducing cycle time and improving inspection accuracy have traditionally been recognized as mutually exclusive, and achieving both has been a long-desired but unsuccessful technical challenge. The inventors of this invention have overcome the conventional technical prejudice that it is common sense to perform visual inspection with a minimum number of devices such as line sensor cameras, thereby breaking the contradiction between reducing cycle time and improving inspection accuracy, solving the long-desired technical challenge, and completing the present invention.

[0011] (1) Based on the above findings, the present invention provides a visual inspection apparatus for a rotating article having the shape of a rotating body, comprising: a plurality of line sensor cameras whose positions and orientations are set in advance and which image the rotating article; and a holding device which holds the rotating article and has a head portion that is rotatable about an axis, wherein the holding device moves the rotating article sequentially to a plurality of imaging positions corresponding to each of the plurality of line sensor cameras, and rotates the head portion about the axis at the imaging position to rotate the rotating article in the circumferential direction.

[0012] In the rotating article appearance inspection apparatus of (1), the rotating article is moved between multiple imaging positions corresponding to multiple line sensor cameras whose positions and orientations are set in advance, eliminating the need to adjust the angle of the rotating article at each imaging position. Therefore, the rotating article appearance inspection apparatus of the present invention can suppress the occurrence of angle deviations when adjusting the angle of the rotating article, and can also shorten the cycle time required for adjusting the angle of the rotating article. Furthermore, in the rotating article appearance inspection apparatus of (1), the entire circumference in the circumferential direction, but only a portion in the radial direction, can be imaged by rotating the rotating article and imaging it with line sensor cameras. Therefore, the rotating article appearance inspection apparatus of the present invention can detect scratches and other defects with higher accuracy compared to imaging with area cameras. As a result, the rotating article appearance inspection apparatus of the present invention can improve inspection accuracy and shorten cycle time, thereby increasing the time efficiency of inspection.

[0013] (2) The rotating body article appearance inspection apparatus of the present invention is the rotating body article appearance inspection apparatus described in (1) above, wherein the holding device moves the rotating body article sequentially to a plurality of imaging positions while maintaining its posture, and rotates the head portion around the axis at each imaging position in that posture to rotate the rotating body article in the circumferential direction.

[0014] In the rotating body object visual inspection apparatus of (2), the rotation of the rotating body object is moved between multiple imaging positions and rotated circumferentially at each imaging position while maintaining the orientation of the rotating body object, thus eliminating the need to adjust the angle of the head at each imaging position. Therefore, in the rotating body object visual inspection apparatus of (2), the occurrence of angle deviations when adjusting the angle of the head can be suppressed, and the cycle time required for adjusting the angle of the head can be shortened. As a result, the rotating body object visual inspection apparatus of (2) can improve inspection accuracy and shorten cycle time, thereby increasing the time efficiency of inspection.

[0015] (3) The rotating body article appearance inspection apparatus of the present invention is the rotating body article appearance inspection apparatus described in (1) or (2) above, wherein the line sensor camera has its focus fixed in advance at the imaging position, and the holding device moves the rotating body article to the imaging position where the line sensor camera is in focus, and rotates the head portion around the axis at the imaging position to rotate the rotating body article in the circumferential direction.

[0016] In the rotating body object visual inspection apparatus described in (3) above, the focus of the line sensor camera is fixed in advance, and the holding device moves the rotating body object to that position. Therefore, in the rotating body object visual inspection apparatus described in (3) above, it is not necessary to adjust the focus of the line sensor camera each time according to the size of the rotating body object. As a result, the rotating body object visual inspection apparatus described in (3) above can improve inspection accuracy and further shorten the cycle time, thereby increasing the time efficiency of inspection.

[0017] (4) The rotating body article appearance inspection device of the present invention is the rotating body article appearance inspection device described in any of (1) to (3) above, wherein the holding device is a robot with fewer than 6 axes.

[0018] In the rotating body object visual inspection device described in (4) above, the complexity of the mechanism and control can be kept low compared to a 6-axis configuration (for example, a robot arm), making it possible to quickly move between multiple imaging positions while ensuring positioning accuracy.

[0019] (5) The rotating body article appearance inspection apparatus of the present invention is the rotating body article appearance inspection apparatus described in (4) above, wherein the plurality of imaging positions are arranged along a plane or line, and the holding device is a multi-joint robot having three or four axes: one or two axes for moving the head portion along the plane or line, one axis for moving the head portion in a direction intersecting the plane or line, and one axis for rotating the head portion.

[0020] In the rotating object visual inspection device of (5), by employing a method of sequentially moving the rotating object to multiple imaging positions corresponding to multiple line sensor cameras whose positions and orientations are set in advance, it is possible to keep the number of axes of the holding device low. In other words, in the rotating object visual inspection device of (5), by reducing the degree of freedom of movement of the head, the positioning of the head can be made more precise. As a result, in the rotating object visual inspection device of (5), the complexity of the mechanism and control of the holding device can be kept low, so that movement between multiple imaging positions can be performed quickly while ensuring positioning accuracy. In other words, in the rotating object visual inspection device of (5), by using a holding device with four axes or less, it is possible to achieve both improved visual inspection accuracy and reduced cycle time.

[0021] (6) The rotating body article appearance inspection apparatus of the present invention is the rotating body article appearance inspection apparatus described in any of (1) to (4) above, wherein the position and orientation of the plurality of line sensor cameras are such that they are positioned and oriented to image a portion of the radial direction of the rotating body article that rotates in the circumferential direction at the imaging position, over the entire circumference, and the imaging results of the plurality of line sensor cameras include the entire area of ​​one side of the rotating body article, and the holding device aligns the central axis of the rotating body article with the axis and maintains the posture of the rotating body article, and sequentially moves the rotating body article to a plurality of imaging positions corresponding to the plurality of line sensor cameras whose positions and orientations are maintained, and at each of the imaging positions the head portion rotates about the axis so that the rotating body article rotates in the circumferential direction and is imaged by the line sensor cameras.

[0022] In the rotating body article visual inspection device of (6), imaging is performed at each imaging position while the axis of the head unit is aligned with the central axis of the rotating body article and the orientation of the rotating body article is maintained. Furthermore, in the rotating body article visual inspection device of (6), the multiple line sensor cameras are positioned and oriented so that a portion of the radial direction of the rotating body article is imaged over the entire circumference in the circumferential direction, and the imaging results of the multiple line sensor cameras cover one side of the rotating body article. As a result, the rotating body article visual inspection device of (6) can image one side of the rotating body article without omission while suppressing the deviation in the relative angle between the axis of the head unit and the orientation of the line sensor cameras, thereby improving the accuracy of the visual inspection. Consequently, the rotating body article visual inspection device of (6) can improve inspection accuracy and shorten the cycle time, thereby increasing the time efficiency of the inspection.

[0023] (7) The rotating body article appearance inspection apparatus of the present invention is the rotating body article appearance inspection apparatus described in any of (1) to (6) above, wherein the holding device is such that the head portion is angled downward or downward during at least a part of the movement of the rotating body article between the imaging positions and the rotation of the head portion.

[0024] According to the rotating body article appearance inspection apparatus of (7), there is no need to turn the head portion upward between the moving operation between the imaging positions and the rotating operation at each imaging position after picking up the rotating body article, and further, the tact time for adjusting the angle of the head portion can be shortened. As a result, the rotating body article appearance inspection apparatus of (7) can improve the inspection accuracy and further enhance the time efficiency of the inspection.

[0025] (8) The rotating body article appearance inspection apparatus of the present invention is the rotating body article appearance inspection apparatus according to any one of the above (1) to (7), and includes one or more illumination devices corresponding to the plurality of line sensor cameras and irradiating light on the rotating body article at the imaging position. The illumination device has one or more illumination portions, and at least one of the illumination portions is a first illumination portion configured to irradiate light on the rotating body article at the imaging position along the direction of the line sensor camera corresponding to the illumination device for at least a part of the light.

[0026] In the rotating body article appearance inspection apparatus of (8), at least a part of the light of the first illumination portion enters the line sensor camera along the optical axis of the line sensor camera. Thereby, the rotating body article appearance inspection apparatus of (8) can detect slight changes such as surface scratches and shallow scratches that cannot be detected by normal illumination (for example, diffused light). As a result, the rotating body article appearance inspection apparatus of (8) can further improve the inspection accuracy and shorten the tact time to enhance the time efficiency of the inspection.

[0027] (9) The rotating body article appearance inspection apparatus of the present invention is the rotating body article appearance inspection apparatus according to any one of the above (1) to (8), and one or more of the illumination devices provided corresponding to the plurality of line sensor cameras include a first illumination portion that irradiates any one of green light, red light, and blue light, and a second illumination portion that irradiates light of a color different from that of the first illumination portion, and the first illumination portion preferably has a larger separation distance from the imaging position than the second illumination portion.

[0028] In the rotating body article appearance inspection device of (9), the first illumination unit is positioned further from the imaging position than the second illumination unit. Therefore, the first illumination unit reflects light with higher parallelism from the rotating body article than the second illumination unit and directs it into the line sensor camera. Furthermore, mirror-like rotating body articles have the characteristic of specular reflection. Consequently, in the rotating body article appearance inspection device of (9), at least a portion of the light from the first illumination unit is incident on the line sensor camera in a specular reflection manner. This makes it possible to detect surface scratches and shallow scratches that cannot be detected by the light from the second illumination unit. In addition, the rotating body article appearance inspection device of (9) is provided with a second illumination unit positioned closer to the imaging position in addition to the first illumination unit. This allows the rotating body article appearance inspection device of (9) to simultaneously detect both normal scratches and slight changes such as surface scratches and shallow scratches that cannot be detected by the light from the second illumination unit. As a result, the rotating body article appearance inspection device of (9) can further improve inspection accuracy and shorten the cycle time, thereby increasing the time efficiency of inspection.

[0029] (10) The rotating article visual inspection device of the present invention is the rotating article visual inspection device described in any of (1) to (9) above, wherein the rotating article may be an O-ring.

[0030] According to the rotating body article visual inspection device of (10), the inspection accuracy of O-rings can be improved and the cycle time can be shortened to increase the time efficiency of the inspection.

[0031] (11) The present invention relates to a method for inspecting the appearance of a rotating article, which uses a rotating article appearance inspection apparatus comprising a line sensor camera for imaging a rotating article having the shape of a rotating body, and a holding device for holding the rotating article, characterized in that the positions and orientations of a plurality of line sensor cameras are set in advance, and the rotating article is moved sequentially to a plurality of imaging positions corresponding to each of the plurality of line sensor cameras (movement step).

[0032] In the rotating body object visual inspection method of (11), the rotating body object is moved between multiple imaging positions corresponding to multiple line sensor cameras whose positions and orientations are set in advance, eliminating the need to adjust the angle of the rotating body object at each imaging position. Therefore, in the rotating body object visual inspection method of (11), the occurrence of angle deviations when adjusting the angle of the rotating body object can be suppressed, and the cycle time required for adjusting the angle of the rotating body object can be shortened. As a result, the rotating body object visual inspection method of (11) can improve inspection accuracy and shorten cycle time, thereby increasing the time efficiency of inspection. [Effects of the Invention]

[0033] According to the present invention, it is possible to provide a rotating body article appearance inspection device and a rotating body article appearance inspection method that can improve inspection accuracy and shorten cycle time to increase the time efficiency of inspection. [Brief explanation of the drawing]

[0034] [Figure 1] This is a schematic diagram showing the overall structure of an O-ring visual inspection device according to an embodiment of the present invention. [Figure 2] This figure shows an example of an O-ring that is inspected by the O-ring visual inspection device shown in Figure 1. (a) is a plan view, (b) is a cross-sectional view when cut along the A1-A1 cross-section in Figure 2(a), and (c) is a cross-sectional view showing the O-ring in close contact with the adhesive. [Figure 3] Figure 1 is an exploded perspective view showing the head section of the O-ring visual inspection device. [Figure 4] This figure shows the positions of the line sensor camera and illumination device of the O-ring visual inspection apparatus shown in Figure 1. (a) is a front view, (b) is a top view, (c) is a magnified view of the main part showing the first illumination light in a top view, and (d) is a magnified view of the main part showing the first illumination light in a front view. [Figure 5] Figure 1 is a front view showing the angle of the camera optical axis of each line sensor camera in the O-ring visual inspection apparatus. [Figure 6] This diagram shows the operation of the O-ring visual inspection device shown in Figure 1. [Figure 7] Figure 1 is a perspective view showing the camera optical axis, illumination light, and inspection target area of ​​the O-ring visual inspection apparatus. [Figure 8] This figure shows the angle of the optical axis, the part to be inspected, and the resulting image at each imaging position of the O-ring visual inspection apparatus shown in Figure 1. [Modes for carrying out the invention]

[0035] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic diagram showing the overall structure of an O-ring appearance inspection device 1 (rotating article appearance inspection device) according to an embodiment of the present invention.

[0036] A "solid of revolution article" is an article that has the shape of a solid of revolution. A solid of revolution is, for example, a three-dimensional shape formed by rotating a planar figure around a single straight line (central axis). Examples of solids of revolution include spheres, right cylindrical cylinders, right circular cones, donut shapes (rings), and coin shapes. Examples of solids of revolution articles include annular articles with an annular appearance and spherical articles with a spherical appearance. An example of annular articles is an O-ring. An example of a spherical article is a sphere used in a ball bearing.

[0037] The O-ring visual inspection device 1 is used to perform a visual inspection of the O-ring K. Specifically, the O-ring visual inspection device 1 is used to inspect the surface of the O-ring K for scratches, deformation, and the presence or absence of deposits (visual inspection). It should be noted that the visual inspection of rotating articles of the present invention is not limited to the visual inspection of O-ring K, but can be applied to the visual inspection of various rotating articles.

[0038] O-rings K are components used to seal fluids such as gases and liquids. O-rings K are used in a variety of fields, including automobiles, hydraulic and pneumatic equipment, household electrical appliances, and semiconductor equipment. O-rings K include, for example, those with a low surface roughness and a glossy, mirror-like finish. The O-ring appearance inspection device of the present invention is particularly suitable for performing appearance inspections of O-rings with a mirror-like surface finish. In this specification, O-rings with a mirror-like surface finish may be simply referred to as "mirror-finish O-rings." A mirror-finish O-ring may, for example, have an arithmetic mean roughness (Ra) of 0.2 μm or less and a maximum height roughness (Rz) of 1.0 μm or less, as measured in accordance with JIS B 0601:2013. The O-ring may have an Ra of 0.1 μm or less and an Rz of 0.5 μm or less. However, the measurement conditions are a cutoff value λc = 0.8 mm and an evaluation length of 5 λc.

[0039] As shown in Figure 2(a), the O-ring K has an annular appearance in plan view. Also, as shown in Figure 2(b), the O-ring K has a cross-sectional shape such as circular (including a perfect circle) or elliptical. Furthermore, the cross-sectional shape of the O-ring K is not particularly limited and can be rectangular, X-shaped, D-shaped (semicircular), V-shaped, H-shaped, U-shaped, T-shaped, L-shaped, etc. In other words, a curved surface is formed on the surface of the O-ring K.

[0040] In this specification, the line passing through the center of the O-ring K in a plan view is referred to as the "central axis C2". The central axis C2 can be said to be the center line when the O-ring K is rotated in the circumferential direction. In this specification, the radial direction of the O-ring K is simply referred to as the "radial direction R". In this specification, the end of the O-ring K in the direction of the central axis C2 is referred to as the "top Kc", the inner end in the radial direction R is referred to as the "inner end Ka", and the outer end in the radial direction R is referred to as the "outer end Kb". In this specification, in a cross-sectional view when the O-ring K is cut along a cross-section containing the central axis C2 (A1-A1 cross-section in Figure 2(a)), the circumferential direction of the cross-section of the O-ring K is referred to as the "circumferential direction B in cross-sectional view".

[0041] As described later, the O-ring K is held in the holding device 10 in close contact with the adhesive body 16 (see Figure 2(c)). In this specification, when the O-ring K is in close contact with the adhesive body 16, the portion of the O-ring K that is in contact with the adhesive body 16 may be referred to as the "contact portion Kd". Also in this specification, when the O-ring K is in close contact with the adhesive body 16, the portion of the O-ring K that is not in contact with the adhesive body 16 (the portion other than the contact portion Kd) may be referred to as the "exposed portion Ke".

[0042] In this specification, when an O-ring K is divided by a virtual plane including its outer end Kb, one portion of the O-ring K is referred to as "one side." One side can be said to be one of the two sides of the O-ring K in the direction of its central axis C2. In this specification, both sides of the O-ring K in the direction of its central axis C2 are simply referred to as "both sides of the O-ring."

[0043] In this specification, one side of the O-ring K that includes the portion that contacts the adhesive 16 (contact portion Kd) may be simply referred to as the "contact side Kf". Also, in this specification, the other side of the O-ring K that is different from the side that includes the portion that contacts the adhesive 16 (contact portion Kd) (contact side Kf) may be simply referred to as the "exposed side Kg".

[0044] In the following explanation, the vertical direction when the O-ring visual inspection device 1 is installed will be simply referred to as "vertical direction Z". Furthermore, within the vertical direction Z, the upper part will be simply referred to as "upper Z1", and the lower part will be simply referred to as "downward Z2".

[0045] Furthermore, in the following explanation, the direction perpendicular to the vertical direction Z (horizontal direction) will be referred to as the "lateral direction N". The lateral direction N includes the front-to-back and left-to-right directions of the O-ring appearance inspection device 1, and can be said to be the horizontal direction perpendicular to the vertical direction Z when the O-ring appearance inspection device 1 is installed.

[0046] As shown in Figure 1, the O-ring visual inspection device 1 includes a holding device 10, multiple line sensor cameras 20, multiple lighting devices 30, and a control device 40.

[0047] As described above, the O-ring appearance inspection device 1 is equipped with multiple line sensor cameras 20. The O-ring appearance inspection device 1 also has multiple imaging positions P corresponding to each line sensor camera 20. The O-ring appearance inspection device 1 moves between each imaging position P while holding the O-ring K with the holding device 10, and takes images of the O-ring K at each imaging position P. In this embodiment, the O-ring appearance inspection device 1 takes four images of one side of the O-ring K.

[0048] [Regarding the holding device] The holding device 10 holds the O-ring K. As shown in Figure 1, the holding device 10 comprises a base portion 19, an arm portion 12, and a head portion 14. As shown in Figure 3, the head portion 14 of the holding device 10 is provided with an adhesive body 16 and a positioning portion 17.

[0049] In this embodiment, the holding device 10 is shown to be a horizontal articulated robot (a so-called SCARA robot: Selective Compliance Assembly Robot Arm) comprising a base portion 19 and an arm portion 12, wherein the arm portion 12 moves so as to pivot relative to the base portion 19. The holding device 10 moves so that the arm portion 12 pivots along the lateral direction N relative to the base portion 19, and moves the O-ring K between a plurality of imaging positions P formed along a single plane (first virtual plane F1).

[0050] More specifically, the holding device 10 of this embodiment is a four-axis articulated robot equipped with four axes 11. In the rotating body visual inspection device of the present invention, the axes include those that move the head portion on a rotational trajectory or rotate the head portion (rotation axis), and those that move the head portion linearly on a linear trajectory (linear axis).

[0051] Specifically, in this embodiment, the holding device 10 is a multi-joint robot equipped with four axes 11: two axes 11a and 11b (two rotation axes) that move the head portion 14 in a circular orbit on one plane (first virtual plane F1), one axis 11c (one linear motion axis) that moves the head portion 14 in a linear orbit in a direction intersecting the first virtual plane F1 (up and down direction Z), and one axis 11d (one rotation axis) that rotates the head portion 14.

[0052] In this embodiment, an example using a horizontal articulated robot as the holding device is shown, but the holding device is not limited to a horizontal articulated robot. For example, various moving devices (e.g., robots) capable of holding and moving rotating articles can be selected as the holding device.

[0053] For example, the holding device may have one or two axes for movement between imaging positions (movement between imaging positions). For example, the holding device may have one linear axis for movement between imaging positions. For example, the holding device may have one rotation axis for movement between imaging positions. For example, the holding device may have two axes (axis configuration: rotation axis-rotation axis) for moving the head on a circular orbit for movement between imaging positions. For example, the holding device may have two axes (axis configuration: rotation axis-linear axis) for movement between imaging positions, consisting of one rotation axis and one linear axis.

[0054] Furthermore, the holding device may be equipped with a single axis for movement (pickup / release operation) between the mounting surface (mounting part) and one surface. For example, the holding device may be equipped with a single linear axis for the pickup / release operation. For example, the holding device may be equipped with a single rotary axis for the pickup / release operation. When a rotating body member is mounted on the mounting part, the holding device may be equipped with a single linear axis for moving the head part vertically for the pickup / release operation.

[0055] Furthermore, the holding device can be designed to have a single axis for the rotation of the head at the imaging position (head rotation movement). For example, the holding device can be designed to have a single axis for the rotation movement of the head.

[0056] Furthermore, the movement between imaging positions is not limited to movement on the first virtual plane F1 (XY plane), but may also be on a plane in the vertical Z direction (ZX plane or ZY plane). Also, the pickup / release operation is not limited to linear movement in the vertical Z direction, but may also be linear movement or rotation in the horizontal N direction (X direction or Y direction).

[0057] The holding device may be a robot with fewer than six axes. This allows for a lower complexity of mechanism and control compared to a six-axis configuration (e.g., a robot arm), enabling rapid movement between multiple imaging positions while maintaining positioning accuracy.

[0058] For example, the holding device can employ four axes or fewer. That is, the holding device can employ any one axis configuration from a 1 to 4-axis configuration. In the rotating article appearance inspection apparatus of the present invention, by employing a method of sequentially moving the rotating article to multiple imaging positions corresponding to multiple line sensor cameras whose positions and orientations are set in advance, it is possible to keep the number of axes of the holding device low. In other words, in the rotating article appearance inspection apparatus of the present invention, by reducing the degree of freedom of movement of the head, the positioning of the head can be made more precise. As a result, the complexity of the mechanism and control of the holding device can be kept low, so that it is possible to move quickly between multiple imaging positions while ensuring positioning accuracy. That is, by using a holding device with four axes or fewer, it is possible to achieve both improved accuracy of appearance inspection and a reduction in cycle time.

[0059] The holding device is not particularly limited and includes, in addition to horizontal articulated robots (SCARA robots), rectangular coordinate robots with three linear axes (axis configuration: linear axis-linear axis-linear axis), cylindrical coordinate robots with three axes consisting of one rotary axis and two linear axes (axis configuration: linear axis-linear axis-rotation axis), polar coordinate robots with three axes consisting of two rotary axes and one linear axis (axis configuration: rotation axis-rotation axis-linear axis), parallel link robots, etc.

[0060] The rotating shaft can, for example, be a motor. The linear shaft may be composed of a motor (e.g., a servo motor) and a ball screw, or it may be composed of a linear motor.

[0061] The head portion 14 is rotatable around the axis C1. As shown in Figure 3, the head portion 14 has a cylindrical exterior and is hollow inside. A negative pressure generating device (not shown) is connected to the head portion 14. This allows the head portion 14 to create negative or positive pressure inside the negative pressure chamber 15. In other words, the holding device 10 is provided with a negative pressure chamber 15 that generates negative pressure.

[0062] In this specification, the orientation of the head portion 14 may be described as follows: when the tip surface 14a is facing downward Z2, it is described as "downward"; when the tip surface 14a is inclined with respect to the lateral direction N, it is described as "diagonal"; and when the tip surface 14a is inclined with respect to the lateral direction N and the tip surface 14a is located below Z2 from the other surface of the head portion 14 (base end surface 14b), it is described as "diagonally downward".

[0063] As shown in Figure 3, the adhesive body 16 and the positioning part 17 are provided on the tip surface 14a of the head part 14. The positioning part 17 is configured such that when the O-ring K is held by the adhesive body 16, its outer peripheral surface contacts at least a portion of the inner peripheral surface of the O-ring K. In the holding device 10 of this embodiment, the tip surface 14a faces downward Z1.

[0064] The adhesive body 16 holds the O-ring K in close contact. The adhesive body 16 has physical adhesive properties. Specifically, the adhesive body 16 is made of a material that has physical adhesive properties due to its flexibility. The adhesive body 16's elastic deformation increases its contact with the O-ring K, allowing it to hold the O-ring K in close contact. In other words, the adhesive body 16 is a material that can temporarily fix an object in close contact without using an adhesive.

[0065] As shown in Figure 3, the adhesive body 16 is provided with a through hole (suction port 18) that communicates with the negative pressure chamber 15. The holding device 10 can generate negative pressure at the suction port 18 while the O-ring K is in close contact with the adhesive body 16 and positioned by the positioning part 17. As a result, the O-ring K is held on the tip surface 14a of the head part 14 by the adhesiveness of the adhesive body 16 and the suction force generated at the suction port 18. The holding device 10 can also remove the O-ring K that is in close contact with the adhesive body 16 by discharging air from the negative pressure chamber 15 through the communication hole (suction port 18).

[0066] As will be described in detail later, the holding device 10 holds the O-ring K and moves it sequentially to four imaging positions P corresponding to the four line sensor cameras 20 (see Figure 6). The holding device 10 also rotates the head portion 14 around the axis C1 at each imaging position P, thereby rotating the O-ring K in the circumferential direction.

[0067] [About line sensor cameras] Next, the configuration of the line sensor camera 20 will be described. The O-ring appearance inspection apparatus 1 is equipped with a plurality of line sensor cameras 20 whose positions and orientations are set in advance. When the orientation of the line sensor camera 20 is set, the angle of the camera optical axis, which is the imaging center line of the line sensor camera 20, is also automatically determined. In the following description, the imaging center line of the line sensor camera 20 will be referred to as the "camera optical axis L1".

[0068] In the O-ring appearance inspection device 1 of this embodiment, a total of four images are taken of one side of the O-ring K, and the four images are capable of covering the entire area of ​​one side of the O-ring K. The O-ring appearance inspection device 1 is equipped with multiple (four in this embodiment) line sensor cameras 20 corresponding to a total of four images. Specifically, as shown in Figure 1, the O-ring appearance inspection device 1 is equipped with a first line sensor camera 20A for taking the first image, a second line sensor camera 20B for taking the second image, a third line sensor camera 20C for taking the third image, and a fourth line sensor camera 20D for taking the fourth image, for one side of the O-ring K.

[0069] In the following explanation, the first line sensor camera 20A, the second line sensor camera 20B, the third line sensor camera 20C, and the fourth line sensor camera 20D will be collectively referred to simply as "line sensor camera 20". Furthermore, in the following explanation, the camera optical axis L1 of the first line sensor camera 20A will be referred to as "first camera optical axis L1a", the camera optical axis L1 of the second line sensor camera 20B as "second camera optical axis L1b", the camera optical axis L1 of the third line sensor camera 20C as "third camera optical axis L1c", and the camera optical axis L1 of the fourth line sensor camera 20D as "fourth camera optical axis L1d".

[0070] The line sensor camera 20 images the O-ring K. In the O-ring appearance inspection apparatus 1 of this embodiment, the line sensor camera 20 is a line sensor camera that images the object in a linear fashion while it is being moved, and combines the linearly captured images to capture a single image. The line sensor camera 20 has a plurality of light-receiving elements configured to detect green light, red light, and blue light, respectively. The line sensor camera 20 images the surface of the O-ring K by having the light-receiving elements detect light reflected from the surface of the O-ring K at the imaging position P (for example, light reflected from the inspection target part S).

[0071] [Regarding the imaging position] The imaging position P is the position where the O-ring K is imaged by the line sensor camera 20. More specifically, the imaging position P is the position where the O-ring K is rotated in the circumferential direction and image is taken. As described above, the O-ring appearance inspection device 1 is equipped with multiple line sensor cameras 20. Therefore, the O-ring appearance inspection device 1 is configured with multiple imaging positions P corresponding to each line sensor camera 20. Specifically, as shown in Figure 1, the O-ring appearance inspection device 1 is configured with a first imaging position P1 corresponding to the first line sensor camera 20A, a second imaging position P2 corresponding to the second line sensor camera 20B, a third imaging position P3 corresponding to the third line sensor camera 20C, and a fourth imaging position P4 corresponding to the fourth line sensor camera 20D.

[0072] As shown in Figure 1, in the O-ring appearance inspection apparatus 1 of this embodiment, the multiple imaging positions P are formed to align with a single plane. Specifically, as shown in Figure 1, the four imaging positions P are formed on a first virtual plane F1 that intersects with the vertical direction Z. In other words, in this embodiment, each imaging position P is positioned on a location from which the head unit 14 can move by the operation of the arm unit 12.

[0073] Furthermore, in the O-ring appearance inspection apparatus 1 of this embodiment, the focus of each line sensor camera 20 is fixed in advance at each imaging position P. The holding device 10 moves the O-ring K to the imaging position P where the line sensor camera 20 is in focus, and rotates the head portion around the axis at the imaging position P to rotate the rotating object in the circumferential direction.

[0074] Thus, in the O-ring appearance inspection device 1, the focus of the line sensor camera 20 is fixed in advance, and the holding device 10 moves the O-ring K to that position. Therefore, the O-ring appearance inspection device 1 does not require the line sensor camera 20 to be refocused each time according to the size of the O-ring K. As a result, the O-ring appearance inspection device 1 can improve inspection accuracy and further shorten the cycle time, thereby increasing the time efficiency of the inspection.

[0075] Furthermore, the rotating body article visual inspection device of the present invention may be configured to allow adjustment of the focus of the line sensor camera depending on the size and type of the rotating body article.

[0076] [Regarding the position of each line sensor camera and the angle of the camera's optical axis] Next, the position of each line sensor camera 20 and the angle of the camera optical axis L1 of each line sensor camera 20 will be explained with reference to Figure 4. Since the position and orientation of each line sensor camera 20 are set in advance, it can be said that the angle of the camera optical axis L1 is also set in advance. In other words, in the O-ring appearance inspection apparatus 1, the line sensor cameras 20 are positioned in advance at fixed positions and orientations, and the O-ring K is moved in front of these line sensor cameras 20 (imaging position P) by the holding device 10.

[0077] As shown in Figure 4(a), in this embodiment, the line sensor camera 20 is positioned so as to be generally facing upward or sideways. That is, in this embodiment, the line sensor camera 20 is configured to image the O-ring K from below Z2. As shown in Figure 4(a), the line sensor camera 20 is positioned and oriented such that the camera optical axis L1 is perpendicular to the imaging center position Pa of the O-ring K. As shown in Figure 4(b), the line sensor camera 20 is positioned and oriented such that the camera optical axis L1 is aligned with the second virtual plane F2 which includes the axis C1 of the head unit 14.

[0078] As shown in Figure 4(a), the line sensor camera 20 is positioned further away from the first illumination unit 32 and the second illumination unit 36 ​​with respect to the imaging position P. In other words, the line sensor camera 20 is positioned behind the first illumination unit 32 with respect to the O-ring K at the imaging position P, with the first illumination unit 32 (described later) in between. To put it another way, the line sensor camera 20 is positioned further away from the first illumination unit 32 with respect to the O-ring K at the imaging position P.

[0079] In this embodiment, the camera optical axis L1 of each line sensor camera 20 is positioned at an angle with respect to the axis C1. Furthermore, the camera optical axis L1 of each line sensor camera 20 is preset to have a different angle with respect to the axis C1. More specifically, the four line sensor cameras 20 are preset to have different angles of camera optical axis L1 with respect to the angle of the axis C1 at the imaging position P (in this embodiment, approximately 0 degrees with respect to the vertical direction Z), and their position and orientation are maintained at that angle. In other words, in the O-ring appearance inspection device 1, multiple line sensor cameras 20 are positioned such that the relative angles of the camera optical axis L1 with respect to the axis C1 are all different.

[0080] In the following explanation, the angle between the camera optical axis L1 and the axis C1 (the relative angle of the camera optical axis L1 with respect to the axis C1) will be referred to as the "relative angle D". Furthermore, the relative angle D between the first camera optical axis L1a and the axis C1 will be referred to as the "first relative angle D1", the relative angle D between the second camera optical axis L1b and the axis C1 as the "second relative angle D2", the relative angle D between the third camera optical axis L1c and the axis C1 as the "third relative angle D3", and the relative angle D between the fourth camera optical axis L1d and the axis C1 as the "fourth relative angle D4".

[0081] As shown in Figure 5(a), the first camera optical axis L1a makes a first relative angle D1 with respect to the axis C1 (for example, an angle of 75 degrees (+75 degrees) clockwise in a front view). That is, the first line sensor camera 20A is positioned such that the first camera optical axis L1a makes a first relative angle D1 with respect to the axis C1. As shown in Figure 5(a), the first line sensor camera 20A is oriented to image mainly the inner circumferential surface including the inner end Ka.

[0082] As shown in Figure 5(b), the second camera optical axis L1b makes a second relative angle D2 with respect to the axis C1 (for example, an angle of 25 degrees (+25 degrees) clockwise in a front view). That is, the second line sensor camera 20B is positioned such that the second camera optical axis L1b makes a second relative angle D2 with respect to the axis C1. As shown in Figure 5(b), the second line sensor camera 20B is oriented to image mainly the portion closer to the inner surface, including the top Kc.

[0083] As shown in Figure 5(c), the third camera optical axis L1c makes a third relative angle D3 with respect to the axis C1 (for example, an angle of 25 degrees (-25 degrees) counterclockwise in a front view). That is, the third line sensor camera 20C is positioned such that the third camera optical axis L1c makes a third relative angle D3 with respect to the axis C1. As shown in Figure 5(c), the third line sensor camera 20C is oriented to image mainly the outer surface portion including the top Kc.

[0084] As shown in Figure 5(d), the fourth camera optical axis L1d makes a fourth relative angle D4 with respect to the axis C1 (for example, an angle of 75 degrees (-75 degrees) counterclockwise in a front view). That is, the fourth line sensor camera 20D is positioned such that the fourth camera optical axis L1d makes a fourth relative angle D4 with respect to the axis C1. As shown in Figure 5(d), the fourth line sensor camera 20D is oriented to image mainly the outer circumferential surface including the outer end Kb.

[0085] Note that the relative angle D exemplified in this embodiment is just one example. The relative angle D of the camera optical axis L1 of each line sensor camera 20 with respect to the axis C1 can be appropriately set according to the number of line sensor cameras 20, the size of the O-ring K, the number of images taken on one side of the O-ring, etc. The number of images taken on one side of the O-ring can also be appropriately selected according to the relative angle, etc.

[0086] [Regarding lighting equipment] As shown in Figure 1, the O-ring appearance inspection apparatus 1 of this embodiment is provided with multiple (four in this embodiment) illumination devices 30, each corresponding to one of the multiple (four in this embodiment) line sensor cameras 20, which illuminate the O-ring K at the imaging position P.

[0087] The illumination device 30 includes at least one illumination unit 31 that irradiates light onto the O-ring K on the imaging position P. In this embodiment, each illumination device 30 has a plurality (three in this embodiment) of illumination units 31. Specifically, as shown in Figure 4(b), the illumination device 30 includes one first illumination unit 32 and two second illumination units 36 as illumination units 31.

[0088] As shown in Figure 4(b), the first illumination unit 32 comprises a housing 33, a half mirror 34, and a light source 35. The housing 33 has a first opening 33a formed at a position facing the line sensor camera 20, and a second opening 33b formed at a position facing the first opening 33a. The first illumination unit 32 is configured with the half mirror 34 and the light source 35 housed within the housing 33. The half mirror 34 is positioned at a 45-degree angle with respect to the direction of illumination of the light emitted from the light source 35. As shown in Figure 4(b), the first illumination unit 32 reflects the first illumination light E1 by 90 degrees using the half mirror 34 and illuminates the O-ring K on the imaging position P through the second opening 33b. On the other hand, the light incident from the second opening 33b (the first illumination light E1 reflected from the surface of the O-ring K) passes through the half mirror 34 and is illuminated outward from the first opening 33a and incident on the line sensor camera 20.

[0089] As shown in Figure 4(a), the first illumination unit 32 is equipped with multiple light sources 35. In this embodiment, the light sources 35 of the first illumination unit 32 are LEDs that emit green light. Therefore, the first illumination light E1 emitted from the first illumination unit 32 is green light. In other words, the first illumination unit 32 emits green first illumination light E1.

[0090] As shown in Figure 4(a), the first illumination unit 32 is located at a greater distance from the imaging position P than the second illumination unit 36. That is, the first illumination unit 32 is positioned further from the imaging position P than the second illumination unit 36. Therefore, as shown in Figure 4(c), the first illumination light E1 reaching the O-ring K on the imaging position P has a smaller incident angle in the width direction W, which intersects both the radial direction R and the central axis C2. Consequently, the line sensor camera 20 images a narrow, band-shaped area in the width direction W of the O-ring K. Here, the specular reflection characteristic of light is strongly exhibited on the mirror-like surface of the O-ring K. Therefore, the first illumination light E1 irradiated onto the O-ring K from the first illumination unit 32 is incident on the line sensor camera 20 with a high degree of parallelism to the camera optical axis L1.

[0091] As described above, in the first illumination unit 32, multiple light sources 35 are arranged in a row. As shown in Figure 4(a), the multiple light sources 35 are arranged to irradiate a portion of the circumferential direction B of the cross-section of the O-ring K. Specifically, as shown in Figure 4(a), the multiple light sources 35 are arranged along a direction intersecting the camera optical axis L1. Therefore, the first illumination light E1 is incident on the O-ring K at the imaging position P over a certain range in the circumferential direction B of the cross-section. In other words, the first illumination unit 32 irradiates the O-ring K with the first illumination light E1 over a predetermined range corresponding to the curved surface of the O-ring K. Also, on the mirror-like surface of the O-ring K, the incident light is reflected specularly according to the curved surface of the O-ring K. Therefore, as shown in Figure 4(d), a portion of the first illumination light E1 irradiated onto the O-ring K from the first illumination unit 32 is reflected along the camera optical axis L1 and incident on the line sensor camera 20.

[0092] Thus, the first illumination unit 32 is configured to irradiate the O-ring K with light that is highly parallel (highly directional). In addition, the first illumination unit 32 is configured to irradiate the O-ring K with light that is specularly reflected (specularly reflected light).

[0093] Here, if the mirror-like surface of the O-ring K is normal and free from scratches, abrasions, etc., most of the light specularly reflected from the surface of the O-ring K will enter the line sensor camera 20. On the other hand, if there are defects such as dents or scratches on the surface of the O-ring K, the first illumination light E1 will be diffusely reflected at the defective part, and the light diffusely reflected at that part will not enter the line sensor camera 20.

[0094] This phenomenon allows for a difference to be created between the amount of light reflected from the normal portion and incident on the line sensor camera 20 and the amount of light reflected from the defective portion and incident on the line sensor camera 20, even if the defects on the mirror-like surface of the O-ring K are shallow dents or scratches, which are difficult to detect with diffused light. Furthermore, the O-ring appearance inspection device 1 can detect defective areas based on this difference in light intensity. Therefore, the O-ring appearance inspection device 1 can capture even slight changes such as surface scratches and shallow damage. As a result, the inspection accuracy of the O-ring appearance inspection device 1 can be further improved.

[0095] As shown in Figure 4(b), the second illumination unit 36 ​​is equipped with a light source 37. As shown in Figure 4(b), in this embodiment, two second illumination units 36 are provided for one first illumination unit 32. As shown in Figure 4(b), the two second illumination units 36 are arranged symmetrically with respect to the camera optical axis L1 in a plan view. In other words, the two second illumination units 36 are arranged so as to separate the camera optical axis L1. The second illumination units 36 emit light of a different color than the first illumination unit 32. Specifically, of the two second illumination units 36, the light source 37a provided in one of the second illumination units 36a is an LED that emits blue light. The light source 37b provided in the other second illumination unit 36b is an LED that emits red light.

[0096] As shown in Figure 4(a), the second illumination unit 36 ​​is located at a smaller distance from the imaging position P than the first illumination unit 32. In other words, the second illumination unit 36 ​​is positioned closer to the imaging position P than the first illumination unit 32. Therefore, the light emitted from the second illumination unit 36 ​​(second illumination light E2) is diffused onto the O-ring K on the imaging position P (see Figure 7). In other words, the second illumination unit 36 ​​emits light with low parallelism (light with low directivity) to the first illumination unit 32. Furthermore, the second illumination unit 36 ​​is configured to emit light with high diffusivity (diffused light).

[0097] As described above, the O-ring appearance inspection apparatus 1 of this embodiment includes a first illumination unit 32 that directs highly parallel light (specularly reflected light) onto the line sensor camera 20, as well as a second illumination unit 36 ​​that directs less parallel light (diffused light) onto the line sensor camera 20. In the O-ring appearance inspection apparatus 1, the multiple illumination units 30 provided to correspond to the multiple line sensor cameras 20 include a first illumination unit 32 that emits green light and a second illumination unit 36 ​​that emits light of a different color than the first illumination unit 32. Furthermore, the first illumination unit 32 is positioned such that its distance from the imaging position P is greater than that of the second illumination unit 36.

[0098] Here, if the O-ring K has defects such as dents or scratches, its edge (wall) is illuminated by the second illumination light E2a and E2b, and the reflected light from this edge is incident on the line sensor camera 20. As a result, the O-ring appearance inspection device 1 can detect abnormalities such as normal scratches and dents. Therefore, the O-ring appearance inspection device 1 can simultaneously detect both normal scratches and slight changes such as surface abrasions and shallow scratches that cannot be detected by the light from the second illumination unit 36.

[0099] [About the control device] The control device 40 controls the operation of the entire device and determines the quality of the O-ring K based on the image captured by the line sensor camera 20. The control device 40 has a hardware configuration that includes a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory), which are not shown in the diagram. In this hardware configuration, the CPU performs calculations according to a predetermined program, and the control device 40 executes operations according to the loaded program.

[0100] The control device 40 is configured with functional units that perform various operations according to the program. For example, as shown in Figure 1, the control device 40 includes an operation control unit 41 and a determination unit 42 as functional units. The operation control unit 41 controls the operation of each component, such as the holding device 10, the line sensor camera 20, and the lighting device 30. The determination unit 42 processes images captured by each line sensor camera 20 using green light, red light, and blue light, and determines from the brightness level whether or not there are defects such as dents or scratches in the O-ring K.

[0101] [Operation of the O-ring visual inspection device] Next, the operation of the O-ring appearance inspection device 1 will be explained with reference to Figure 6. The operation of the O-ring appearance inspection device 1 described below is performed under the control of the control device 40 (operation control unit 41). Furthermore, the operation of the O-ring appearance inspection device 1 described below can be said to be each step of a method for inspecting the appearance of an O-ring K (rotating body article appearance inspection method). Specifically, the O-ring appearance inspection method includes a step of holding the O-ring K (holding step), a step of moving the O-ring K (moving step), and a step of rotating the O-ring K and taking an image (imaging step).

[0102] The O-ring appearance inspection device 1 first operates the holding device 10 to pick up the O-ring K placed on the mounting surface 2 (holding process). Specifically, as shown in Figure 6(a), the O-ring appearance inspection device 1 presses the head portion 14 against the O-ring K placed on the mounting surface 2, causing the O-ring K to adhere tightly to the adhesive body 16 (see Figure 3). At this time, the holding device 10 moves the head portion 14 in the vertical direction Z for movement between the mounting surface 2 and the first virtual plane F1 (pickup / release operation). The head portion 14 is equipped with a position identification camera (not shown), which extracts the position of the central axis C2 of the O-ring K, and presses the head portion 14 against the O-ring K at a position where the axis C1 and the central axis C2 coincide. When the head portion 14 is pressed against the O-ring K, the adhesive body 16 is pressed against the O-ring K and elastically deforms, causing the adhesive body 16 to adhere tightly to the O-ring K. The O-ring K is held in place by the adhesive properties of the adhesive body 16 and the negative pressure of the suction port 18, which are located in the head portion 14.

[0103] As shown in Figure 6(b), the O-ring visual inspection device 1 holds the O-ring K in the head portion 14, and then raises the head portion 14. As shown in Figure 6(b), in this embodiment, when the O-ring K is held in the head portion 14, the head portion 14 is facing downward Z2.

[0104] As shown in Figure 6(c), the O-ring appearance inspection device 1 holds the O-ring K in the head unit 14, and then moves the head unit 14 to the first imaging position P1 while holding the O-ring K with the axis C1 and the central axis C2 aligned, and maintaining the orientation of the head unit 14 (the orientation of the O-ring K) facing downward Z2 (first movement step). Specifically, in the O-ring appearance inspection device 1 of this embodiment, the holding device 10 holds the O-ring K by making it tightly adhered to the adhesive body 16, and then raises the head unit 14 to a position at the same height as the first imaging position P1 (first virtual plane F1) (see Figure 6(b)). Next, the holding device 10 moves the head unit 14 in the lateral direction N on the first virtual plane F1 (movement between imaging positions). In other words, the holding device 10 holds the O-ring K and raises it to the first virtual plane F1, and then moves the head unit 14 in the lateral direction N to move to the first imaging position P1 (movement between imaging positions).

[0105] The O-ring appearance inspection device 1 images the O-ring K at the first imaging position P1 while maintaining the position of the head unit 14. Specifically, the O-ring appearance inspection device 1 irradiates the O-ring K with light using the first illumination unit 32 and the second illumination unit 36 ​​while maintaining the position and orientation of the O-ring K at the first imaging position P1. In addition, while imaging the O-ring K at the first imaging position P1, the O-ring appearance inspection device 1 rotates the head unit 14 once around the axis C1, while aligning the axis C1 and the central axis C2 (head unit rotation operation). As a result, a part of the radial R of the O-ring K (inspection target part S) is irradiated with light, and the entire circumference of that part is imaged (first imaging step). The position and range of the inspection target part S by the first line sensor camera 20A will be described in detail later.

[0106] Once imaging at the first imaging position P1 is complete, the O-ring appearance inspection device 1 moves the O-ring K to the second imaging position P2 (second movement step). Specifically, as shown in Figure 6(d), the O-ring appearance inspection device 1 holds the O-ring K with the axis C1 and the central axis C2 aligned, and while maintaining the orientation of the head unit 14 (the posture of the O-ring K) facing downward Z2, moves the head unit 14 laterally in the direction N from the first imaging position P1 to the second imaging position P2 (movement between imaging positions).

[0107] The O-ring appearance inspection device 1 operates similarly to the operation at the first imaging position P1. At the second imaging position P2, while maintaining the position of the O-ring K, the head unit 14 rotates around the axis C1 (head unit rotation operation) to rotate the O-ring K in the circumferential direction and take an image (second imaging step). The position and range of the inspection target part S by the second line sensor camera 20B will be described in detail later.

[0108] Once imaging at the second imaging position P2 is complete, the O-ring appearance inspection device 1 moves the O-ring K to the third imaging position P3 (third movement step). Specifically, as shown in Figure 6(e), the O-ring appearance inspection device 1 holds the O-ring K with the axis C1 and the central axis C2 aligned, and while maintaining the orientation of the head unit 14 (the posture of the O-ring K) facing downward Z2, moves the head unit 14 laterally in the direction N from the second imaging position P2 to the third imaging position P3 (movement between imaging positions).

[0109] The O-ring appearance inspection device 1 operates similarly to the operation at the first imaging position P1. At the third imaging position P3, while maintaining the position of the O-ring K, the head unit 14 rotates around the axis C1 (head unit rotation operation) to rotate the O-ring K in the circumferential direction and take an image (third imaging step). The position and range of the inspection target part S by the third line sensor camera 20C will be described in detail later.

[0110] Once imaging at the third imaging position P3 is complete, the O-ring appearance inspection device 1 moves the O-ring K to the fourth imaging position P4 (fourth movement step). Specifically, as shown in Figure 6(f), the O-ring appearance inspection device 1 holds the O-ring K with the axis C1 and the central axis C2 aligned, and while maintaining the orientation of the head unit 14 (the posture of the O-ring K) facing downward Z2, moves the head unit 14 laterally in the direction N from the third imaging position P3 to the fourth imaging position P4 (movement between imaging positions).

[0111] The O-ring visual inspection device 1, in the same manner as its operation at the first imaging position P1, maintains the position of the O-ring K at the fourth imaging position P4, and rotates the head unit 14 around the axis C1 (head unit rotation operation) to rotate the O-ring K in the circumferential direction and take an image (fourth imaging step). The position and range of the inspection target part S by the fourth line sensor camera 20D will be described in detail later.

[0112] Once imaging at the fourth imaging position P4 is complete, the O-ring appearance inspection device 1 discharges air from the suction port 18 to temporarily remove the O-ring K, inverts the O-ring K, and similarly images the other side of the O-ring K.

[0113] Images captured by each line sensor camera 20 are transmitted to the control device 40, where the control device 40 (determination unit 42) processes the images and determines whether or not there are defects such as dents or scratches in the O-ring K based on its brightness level.

[0114] In the O-ring appearance inspection device 1, the O-ring K is moved between multiple imaging positions P corresponding to multiple line sensor cameras 20 whose positions and orientations are pre-set, eliminating the need to adjust the angle of the O-ring K at each imaging position P. Therefore, the O-ring appearance inspection device 1 can suppress the occurrence of angle deviations when adjusting the angle of the O-ring K, and can also shorten the cycle time required for adjusting the angle of the O-ring K. As a result, the O-ring appearance inspection device 1 can improve inspection accuracy and shorten cycle time, thereby increasing the time efficiency of inspection.

[0115] The O-ring visual inspection device 1 has a line sensor camera 20. The holding device 10 has a head portion 14 that can rotate around the axis C1, and rotates the head portion 14 around the axis C1 at the imaging position P to rotate the O-ring K in the circumferential direction.

[0116] As a result, the O-ring appearance inspection device 1 can image the entire circumference of the O-ring K, including a portion of the radial radius R. Therefore, the O-ring appearance inspection device 1 can detect defects and other imperfections with greater accuracy compared to imaging with an area camera. Consequently, the O-ring appearance inspection device 1 can further improve inspection accuracy and shorten the cycle time, thereby increasing the time efficiency of the inspection.

[0117] As described above, the O-ring appearance inspection device 1 moves the O-ring K sequentially to multiple imaging positions P while maintaining the orientation of the O-ring K with the holding device 10, and rotates the head unit 14 around the axis C1 at each imaging position P to rotate the O-ring K in the circumferential direction.

[0118] As a result, the O-ring appearance inspection device 1 eliminates the need to adjust the angle of the head unit 14 at each imaging position P by maintaining the orientation of the O-ring K while moving the O-ring K between multiple imaging positions P and rotating it circumferentially at each imaging position P. Therefore, the O-ring appearance inspection device 1 can suppress the occurrence of angle deviations when adjusting the angle of the head unit 14, and can also shorten the cycle time required for adjusting the angle of the head unit 14. Consequently, the O-ring appearance inspection device 1 can improve inspection accuracy and shorten cycle time, thereby increasing the time efficiency of inspection.

[0119] The O-ring appearance inspection device 1 has a holding device 10 which has a head portion 14 that can rotate around the axis C1, and the head portion 14 is angled downward or downward during both the movement of the O-ring K between imaging positions P (movement between imaging positions) and the rotation of the head portion 14 (head portion rotation movement).

[0120] Therefore, in the O-ring appearance inspection device 1, there is no need to raise the head unit 14 between the movement of the O-ring K between each imaging position P and the rotational movement at each imaging position P, and the cycle time for adjusting the angle of the head unit 14 can be shortened. As a result, the O-ring appearance inspection device 1 can improve inspection accuracy and further increase the time efficiency of inspection.

[0121] The O-ring visual inspection device 1 has multiple imaging positions P formed along a single plane (first virtual plane F1). The holding device 10 is a horizontal articulated robot that moves the O-ring K between the multiple imaging positions P formed along the first virtual plane F1.

[0122] Thus, in the O-ring appearance inspection device 1, by configuring multiple imaging positions P in the lateral direction N and employing a horizontally articulated robot with a simple configuration, the operation of the holding device 10 when moving the O-ring K between imaging positions P can be simplified. As a result, the O-ring appearance inspection device 1 can improve inspection accuracy and shorten cycle time, further increasing the time efficiency of inspection.

[0123] [Regarding the parts to be inspected by each line sensor camera] Next, the inspection target area S at each imaging position P will be described with reference to Figures 7 and 8.

[0124] In the O-ring appearance inspection device 1, the O-ring K is divided into multiple parts (four parts) in the radial direction R, and these parts are imaged by corresponding line sensor cameras 20. In the O-ring appearance inspection device 1, by setting the angles of multiple (four in this embodiment) line sensor cameras 20 to angles corresponding to the multiple parts in the radial direction R (circumferential direction B when viewed in cross-section) of the O-ring K, one side of the O-ring K can be inspected without omission. In other words, in the O-ring appearance inspection device 1, one side of the O-ring K can be inspected without omission by imaging the surface of the O-ring K multiple times at different angles.

[0125] As described above, the O-ring appearance inspection device 1 is configured to specularly reflect at least a portion of the light from the first illumination unit 32 off the surface of the O-ring K, and to direct that light into the line sensor camera 20. Furthermore, the O-ring appearance inspection device 1 can detect even slight changes in the O-ring K by directing the light from the first illumination unit 32 into the line sensor camera 20 along the camera optical axis L1 (by directing specularly reflected light).

[0126] Therefore, as shown in Figure 7, the portion of the O-ring K that reflects the first illumination light E1 as specularly reflected light (light with high parallelism) can be said to be the portion to be inspected by the O-ring appearance inspection device 1. From the opposite perspective, the portion to be inspected can be said to be the portion that specularly reflects the light of the first illumination light E1 toward the line sensor camera 20. In the following explanation, the portion of the O-ring K that reflects the first illumination light E1 as specularly reflected light (light with high parallelism) will be referred to as the "inspection target portion S".

[0127] Furthermore, the inspection target S by the first line sensor camera 20A will be referred to as "first inspection target S1," the inspection target S by the second line sensor camera 20B as "second inspection target S2," the inspection target S by the third line sensor camera 20C as "third inspection target S3," and the inspection target S by the fourth line sensor camera 20D as "fourth inspection target S4."

[0128] As shown in Figure 8(a-1), the first camera optical axis L1a is set to an angle and position that captures images centered on the inner circumferential surface portion of the radial direction R of the O-ring K, including the inner end Ka. Also, as shown in Figure 8(a-1), the first illumination light E1, specularly reflected by the inner circumferential surface portion including the inner end Ka, is incident on the first line sensor camera 20A along the first camera optical axis L1a. Therefore, the inner circumferential surface portion of the O-ring K, including the inner end Ka, can be said to be the first inspection target portion S1 that reflects the light of the first illumination light E1 so that it is incident on the first line sensor camera 20A along the first camera optical axis L1a.

[0129] The O-ring appearance inspection device 1 rotates the head unit 14 while irradiating the first inspection target part S1 with the first illumination light E1, thereby imaging the O-ring K with the first line sensor camera 20A so as to include the entire circumference of the first inspection target part S1. Furthermore, as shown in Figure 8(a-2), the O-ring appearance inspection device 1 acquires a first image G1 as an imaging result, which includes an image of the entire circumference of the first inspection target part S1 irradiated with highly parallel light (first illuminated image part G1a) by imaging with the first line sensor camera 20A.

[0130] As shown in Figure 8(b-1), the second camera optical axis L1b is set to an angle and position that captures images mainly from the portion of the O-ring K's radial direction R that is closer to the inner surface, including the top Kc. Also, as shown in Figure 8(b-1), the first illumination light E1, which is specularly reflected from the portion of the O-ring K's inner surface including the top Kc, is incident on the second line sensor camera 20B along the second camera optical axis L1b. Therefore, the portion of the O-ring K's inner surface including the top Kc can be said to be the second inspection target part S2 that reflects the light of the first illumination light E1 so that it is incident on the second line sensor camera 20B along the second camera optical axis L1b.

[0131] The O-ring appearance inspection device 1 rotates the head unit 14 while irradiating the second inspection target part S2 with the first illumination light E1, thereby imaging the O-ring K with the second line sensor camera 20B so as to include the entire circumference of the second inspection target part S2. Furthermore, as shown in Figure 8(b-2), the O-ring appearance inspection device 1 acquires a second image G2 as an imaging result, which includes an image of the entire circumference of the second inspection target part S2 (second illuminated image part G2a) irradiated with highly parallel light, by imaging with the second line sensor camera 20B.

[0132] As shown in Figure 8(c-1), the third camera optical axis L1c is set to an angle and position that captures images mainly from the portion of the O-ring K's radial direction R that is closer to the outer surface, including the top Kc. Also, as shown in Figure 8(c-1), the first illumination light E1, which is specularly reflected from the portion of the O-ring K's outer surface that includes the top Kc, is incident on the third line sensor camera 20C along the third camera optical axis L1c. Therefore, the portion of the O-ring K's outer surface that includes the top Kc can be said to be the third inspection target part S3 that reflects the light of the first illumination light E1 so that it is incident on the third line sensor camera 20C along the third camera optical axis L1c.

[0133] The O-ring appearance inspection device 1 rotates the head unit 14 while irradiating the third inspection target S3 with the first illumination light E1, thereby imaging the O-ring K with the third line sensor camera 20C so as to include the entire circumference of the third inspection target S3. Furthermore, as shown in Figure 8(c-2), the O-ring appearance inspection device 1 acquires a third image G3 as an imaging result, which includes an image of the entire circumference of the third inspection target S3 (third illuminated image unit G3a) irradiated with highly parallel light, by imaging with the third line sensor camera 20C.

[0134] As shown in Figure 8(d-1), the fourth camera optical axis L1d is set to an angle and position that captures images centered on the outer peripheral surface portion of the radial direction R of the O-ring K, including the outer end Kb. The O-ring K at the fourth imaging position P4 is illuminated by the first illumination unit 32 with the first illumination light E1. As also shown in Figure 8(d-1), the first illumination light E1, which has been specularly reflected off the outer peripheral surface portion including the outer end Kb, is incident on the fourth line sensor camera 20D along the fourth camera optical axis L1d. Therefore, the outer peripheral surface portion of the O-ring K, including the outer end Kb, can be said to be the fourth inspection target portion S4 that reflects the light of the first illumination light E1 so that it is incident on the fourth line sensor camera 20D along the fourth camera optical axis L1d.

[0135] The O-ring appearance inspection device 1 rotates the head unit 14 while irradiating the fourth inspection target S4 with the first illumination light E1, thereby imaging the O-ring K with the fourth line sensor camera 20D so as to include the entire circumference of the fourth inspection target S4. Furthermore, as shown in Figure 8(d-2), the O-ring appearance inspection device 1 acquires a fourth image G4 as an imaging result, which includes an image of the entire circumference of the fourth inspection target S4 (fourth illuminated image unit G4a) irradiated with highly parallel light, through imaging by the fourth line sensor camera 20D.

[0136] Thus, the O-ring appearance inspection device 1 captures an image of a portion of the radial direction R (the inspection target area S) of the O-ring K, which rotates circumferentially, over its entire circumference at the imaging position P. Furthermore, the imaging results for four patterns of relative angles D are configured to cover the entire area of ​​one side of the O-ring K. In addition, the four imaging results include an image of the portion (image of the inspection target area S) where specularly reflected light (light with high parallelism) is reflected, covering the entire area of ​​one side of the O-ring K. As a result, the O-ring appearance inspection device 1 can inspect one side of the O-ring K with high accuracy and without omission.

[0137] Furthermore, the O-ring visual inspection device 1 is designed to hold the O-ring K while ensuring a large exposed area of ​​the O-ring K, so that both the inner end Ka and the outer end Kb are exposed, by making the O-ring K tightly adhered to the adhesive body 16. Therefore, the O-ring visual inspection device 1 can allow the inner end Ka and the outer end Kb to overlap in the inspection results on both sides. As a result, the O-ring visual inspection device 1 enables high-precision visual inspection without leaks.

[0138] Furthermore, in the O-ring appearance inspection device 1, the four line sensor cameras 20 are positioned such that their angles and the angle of the camera optical axis L1 capture images of a portion of the radial direction R of the O-ring K (the part to be inspected S) as it rotates circumferentially at the imaging position P, and the imaging results from the four line sensor cameras 20 include the entire area of ​​one side of the O-ring K. In addition, in the O-ring appearance inspection device 1, imaging is performed at each imaging position P while the axis C1 of the head unit 14 and the central axis C2 of the O-ring K are aligned and the orientation of the O-ring K is maintained.

[0139] As a result, the O-ring visual inspection device 1 can image one side of the O-ring K without omission while suppressing the relative angular deviation between the axis C1 of the head unit 14 and the camera optical axis L1, thereby improving the accuracy of the visual inspection. Consequently, the O-ring visual inspection device 1 can improve inspection accuracy and shorten the cycle time, thereby increasing the time efficiency of the inspection.

[0140] Although embodiments of the O-ring appearance inspection apparatus of the present invention have been described above, the O-ring appearance inspection apparatus of the present invention is not limited to the embodiments described above.

[0141] In the above-described embodiment, an example was shown in which the axis C1 of the head portion 14 is arranged along the vertical direction Z, but the orientation of the axis C1 is not limited to the vertical direction. That is, the orientation of the axis of the head portion can be selected in various ways. For example, the axis of the head portion may be configured to be inclined with respect to the vertical direction, or it may be configured to be in the horizontal direction.

[0142] In the above-described embodiment, an example was shown in which an adhesive body 16, a negative pressure chamber 15, and a suction port 18 are provided on the head portion 14. However, the configuration for holding the O-ring is not limited to this embodiment. In other words, the O-ring may be held in a configuration that does not rely on an adhesive body or suction.

[0143] In the above-described embodiment, an example was shown that included four line sensor cameras 20, but the O-ring appearance inspection device of the present invention may include any number of line sensor cameras. That is, the number of line sensor cameras may be two, three, or five or more.

[0144] In the above-described embodiment, an example was shown in which one line sensor camera 20 images one inspection target part S. However, the O-ring appearance inspection apparatus of the present invention may be configured to image multiple inspection target parts with one line sensor camera. For example, O-rings may be placed at multiple positions relative to one camera, and multiple parts of the O-ring (e.g., the outer and inner surfaces) may be imaged with one line sensor camera.

[0145] In the above embodiment, one side of the O-ring is imaged with four line sensor cameras, and the other side is imaged after the O-ring is flipped over. However, line sensor cameras may be provided to image both sides of the O-ring. For example, one side of the O-ring may be imaged with multiple (e.g., four) line sensor cameras, and then multiple (e.g., four) more line sensor cameras may be provided to image the other side.

[0146] In the above-described embodiment, an example was shown in which one side of the O-ring K is imaged four times to cover one side of the O-ring K. However, the system may be configured to perform three images on one side of the O-ring, or to perform five or more images.

[0147] In the above-described embodiment, an example was shown in which a lighting device 30 is provided for each line sensor camera 20, corresponding to each line sensor camera 20. However, the O-ring appearance inspection apparatus of the present invention is not limited to the above-described embodiment. For example, a lighting device common to multiple line sensor cameras may be provided. For example, one lighting device common to multiple line sensor cameras may be provided to accommodate these line sensor cameras.

[0148] In the above-described embodiment, an example was shown in which a second illumination unit 36 ​​is provided in addition to the first illumination unit 32, but a configuration without the second illumination unit is also possible. Furthermore, in the above-described embodiment, an example was shown in which the second illumination unit emits diffused light, but the second illumination unit may be configured to emit light with high parallelism. In addition, in the above-described embodiment, an example was shown in which the first illumination unit 32 emits green light and the second illumination unit 36 ​​emits red light and blue light, but the color of the light from the first illumination unit and the second illumination unit is not limited to the above-described embodiment, and the color of the light from the first illumination unit and the second illumination unit can be selected as appropriate.

[0149] Although one embodiment of the present invention has been described above, the specific embodiments that the present invention can take are not limited to the embodiments described above. [Explanation of Symbols]

[0150] 1. O-ring visual inspection device 10 Holding device 12 Arm section 14 Head section 20-line sensor camera 20A First Line Sensor Camera (Line Sensor Camera) 20B Second Line Sensor Camera (Line Sensor Camera) 20C Third Line Sensor Camera (Line Sensor Camera) 20D 4th Line Sensor Camera (Line Sensor Camera) 30 Lighting devices 31. Lighting section (lighting equipment) 32. First Lighting Section (Lighting Equipment, Lighting Unit) 36. Second Lighting Section (Lighting Equipment, Lighting Unit) 36a Second Lighting Section (Lighting Device, Lighting Unit) 36b Second Lighting Section (Lighting Equipment, Lighting Unit) C1 axis center C2 center axis D1 angle D2 angle D3 Angle D4 Angle G1 First image (imaging result) G2 Second image (imaging results) G3 Third image (imaging result) G4 4th image (imaging results) KO Ring L1 Camera Optical Axis L1a First camera optical axis (camera optical axis) L1b Second camera optical axis (camera optical axis) L1c Third camera optical axis (camera optical axis) L1d 4th camera optical axis (camera optical axis) P imaging position P1 First imaging position (imaging position) P2 Second imaging position (imaging position) P3 Third imaging position (imaging position) P4 4th imaging position (imaging position)

Claims

1. An appearance inspection device for performing an appearance inspection of a rotating body article having the shape of a rotating body, Multiple line sensor cameras, whose positions and orientations are pre-set, capture images of the rotating object, The device comprises a holding device having a head portion that holds the aforementioned rotating article and is rotatable around its axis, The holding device is characterized by sequentially moving the rotating article to a plurality of imaging positions corresponding to a plurality of line sensor cameras, and rotating the head portion around the axis at the imaging position to rotate the rotating article in the circumferential direction.

2. The rotating body article appearance inspection apparatus according to claim 1, characterized in that the holding device moves the rotating body article sequentially to a plurality of imaging positions while maintaining its posture, and rotates the head portion in the circumferential direction around the axis at each imaging position to rotate the rotating body article in that posture.

3. The line sensor camera has its focus fixed in advance at the imaging position. The rotating body article appearance inspection apparatus according to claim 1, characterized in that the holding device moves the rotating body article to the imaging position where the line sensor camera is in focus, and rotates the head portion around the axis at the imaging position to rotate the rotating body article in the circumferential direction.

4. The rotating body article appearance inspection apparatus according to claim 1, characterized in that the holding device is a robot with fewer than 6 axes.

5. The multiple imaging positions are arranged along a single plane or line. The rotating body article appearance inspection apparatus according to claim 4, characterized in that the holding device is a multi-joint robot having three or four axes: one or two axes for moving the head portion on one of the planes or lines, one axis for moving the head portion in a direction intersecting the plane or line, and one axis for rotating the head portion.

6. The multiple line sensor cameras are positioned and oriented such that they capture images of a portion of the radial direction of the rotating article that rotates circumferentially at the imaging position, over the entire circumference, and the imaging results of the multiple line sensor cameras include the entire area of ​​one side of the rotating article. The holding device aligns the central axis of the rotating article with the axis and maintains the orientation of the rotating article, while sequentially moving the rotating article to multiple imaging positions corresponding to multiple line sensor cameras, each of which maintains its position and orientation. The rotating body article appearance inspection apparatus according to claim 1, characterized in that the head portion rotates about the axis at each of the aforementioned imaging positions, causing the rotating body article to rotate in the circumferential direction while being imaged by the line sensor camera.

7. The holding device is The rotating body article appearance inspection apparatus according to claim 1, characterized in that the head portion is angled downward or downward during at least a portion of the movement of the rotating body article between the imaging positions and the rotation of the head portion.

8. The system includes one or more illumination devices that correspond to multiple line sensor cameras and illuminate the rotating body article at the imaging position with light, The rotating body article appearance inspection apparatus according to claim 1, characterized in that the illumination device has one or more illumination units, and at least one of the illumination units is a first illumination unit configured to irradiate at least a portion of the light onto the rotating body article at the imaging position in line with the orientation of the line sensor camera corresponding to the illumination device.

9. One or more of the lighting devices provided to correspond to multiple line sensor cameras are: The first illumination unit emits one of the following: green light, red light, or blue light. The system includes a second illumination unit that emits light of a different color from the first illumination unit, The rotating body article appearance inspection apparatus according to claim 8, characterized in that the distance of the first illumination unit from the imaging position is greater than that of the second illumination unit.

10. The rotating article appearance inspection apparatus according to claim 1, characterized in that the rotating article is an O-ring.

11. A method for inspecting the appearance of a rotating body article using a rotating body article appearance inspection apparatus comprising a line sensor camera for imaging a rotating body article having the shape of a rotating body, and a holding device for holding the rotating body article, The positions and orientations of multiple line sensor cameras are set in advance. A method for inspecting the appearance of a rotating article, characterized by sequentially moving the rotating article to multiple imaging positions corresponding to each of the multiple line sensor cameras.

Images