JP4122099B2 - Inspection method for annular rubber seal member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inspection method for an annular rubber seal member.
[0002]
[Prior art]
Conventionally, as a method for inspecting whether or not there are burrs and chips on the inner and outer circumferences of an annular rubber seal member used in fluid devices, for example, the applicant of the present application is Japanese Patent Application No. 8-40470. As proposed by No., etc., light is applied to the O-ring (as an annular rubber seal member) by coaxial incident light, the entire O-ring is captured as an image, binarized, and a circular shape with a preset size. The window and the center of the captured image are matched (center of gravity coincidence), and the number of white pigments (or the number of black pigments) is counted along the entire circumference of the window.
[0003]
[Problems to be solved by the invention]
Such a conventional inspection method has no problem because an image is input into the field of view of the camera if the annular rubber seal member has a small diameter and a relatively perfect circle. However, for example, a large-diameter rubber seal member is easily deformed into an ellipse, and when the entire image of the ellipse is captured, an erroneous determination occurs if the captured image and the inspection area of the window are overlapped and inspected. There was a problem that. In addition, the accuracy of binarized monochrome pixel determination was poor.
[0004]
Therefore, an object of the present invention is to provide a method for inspecting an annular rubber seal member that can be inspected easily and with high accuracy.
[0005]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides an inspection method for inspecting a lip formed on the outer peripheral edge of a uni-piston as an annular rubber seal member, wherein the uni-piston is installed on a horizontal rotary table. The solid edge of the lip is irradiated with light in the horizontal direction by an illumination lamp from the outer peripheral side, and the light reflected by the end face of the lip is received by the upper solid-state imaging device camera . An image sensor camera is arranged, the rotary table is rotated intermittently, the partial image of the circumference of the end surface of the lip is captured by the solid-state image sensor camera , and the coordinates of three points on the circumference of the captured image The center position and radius of the virtual circle are calculated from the obtained coordinates and circle equation, the virtual circle passing through the coordinates is set, and an area composed of a plurality of pixels having multi-level luminance information is defined as the virtual circle. Along the circle A plurality of setting and setting the inspection area, calculate the average value of the luminance in each area of the inspection area to obtain the luminance of each area, and then the maximum value of the luminance difference between adjacent areas, and The difference between the maximum luminance value and the minimum luminance value in all areas is determined to determine whether or not a predetermined non-defective product determination condition is satisfied, and if the non-defective product determination condition is satisfied, the rotary table is intermittently turned to Other partial images of the circumference of the end surface of the lip are sequentially taken to determine whether or not the non-defective product determination condition is satisfied through the same process, and the non-defective product determination is performed for the entire circumference of the lip as the annular rubber seal member If the condition is satisfied, it is determined that the product is non-defective .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
[0007]
Test method of the present invention is, for example, a method of examining Figure 3 and the outer peripheral edge of the lip 2 Uni piston 1 of an automatic transmission for a seal such as shown in FIG. 4 as an annular rubber seal member 7.
[0008]
FIG. 8 is a flowchart of the inspection method according to the present invention. The inspection method for the lip 2 (annular rubber seal member 7) of the uni-piston 1 will be described with reference to FIGS . 8, 3 and 4. FIG. At the lip 2 of the uni-piston 1, light is irradiated onto a part of the end surface 2 a of the circumference of the lip 2, and the reflected light is incident on a solid-state imaging device (CCD) camera 3, so that a partial image of the lip 2 is obtained. Capture. Specifically, for example, the uni-piston 1 is installed on the rotary table 4, and the illumination lamp 12 irradiates light from the outer peripheral side (arrow G direction) at an angle of 45 ° with respect to the end face 2a of the lip 2. The light reflected at an angle of ° (in the direction of arrow H) is captured by the upper camera 3.
[0009]
As shown in FIG. 1, reference numeral 5 denotes a screen (camera field of view). A partial image of the circumference of the lip 2 captured by the camera 3, that is, a captured image 6 is displayed on the screen 5. It is. In the captured image 6, the portion corresponding to the end surface 2 a of the lip 2 is displayed brightly (white) as the white arc-shaped portion 17, and the background portion 19 is displayed darkly (black). Note that the screen 5 has, for example, 512 horizontal pixels × 484 vertical pixels (described later), and each pixel has luminance information of 0 to 255, for example.
[0010]
By the way, as shown in FIGS. 1 and 3, the lip 2 of the uni-piston 1 installed on the rotary table 4 is soft and easily deformed. When viewed in plan, it is not a perfect circle but an ellipse. There may be. Therefore, in the present invention, the inspection proceeds as described later.
[0011]
As shown in FIGS. 2, 5, and 8, the xy of three arbitrary points A, B, and C on the circumference of the captured image 6 ──the outer peripheral edge of the white arc-shaped portion 17. Find the coordinates. That is, the coordinates (x ₁ , y ₁ ) of point A, the coordinates (x ₂ , y ₂ ) of point B, and the coordinates (x ₃ , y ₃ ) of point C are obtained. Then, the center O position of the virtual circle—the coordinates (a, b) of the center O—and the radius r are calculated from the obtained coordinates and the equation of the circle, and the three points A, B, C are calculated. A virtual circle 8 passing through the coordinates is set.
[0012]
Thereafter, as shown in FIGS. 6 and 8, a plurality of areas E... Are set and arranged along the virtual circle 8 to set the inspection region 9. In the case of the illustrated example, an inspection area 9 consisting of 11 areas E... (E ₁ , E ₂ , E ₃ , E ₄ ...) Is set.
[0013]
By the way, as shown in FIG. 7, one area E is composed of a plurality of pixels F (described above) for detecting luminance. In the case of the illustrated example, one area E is formed from _nine pixels F... (F _{1 to} F ₉ ). One pixel F has luminance information of 0 to 255, for example. The size of the area E can be changed and may be set to an appropriate size corresponding to the type and size of the object to be inspected (annular rubber seal member).
[0014]
Next, as shown in FIGS. 6 to 8, the average value of the luminance in each area E... Of the inspection region 9 is calculated to obtain the luminance for each area E. That is, the average value of the luminances of the plurality of pixels F _{1 to} F ₉ in _one area E is set as the luminance value of the area E. For example, in FIG. 7, the brightness of the pixel F _{1 in} area E is 85, the brightness of F ₂ is 84, F ₃ is 83, F ₄ is 83, F ₅ is 82, F ₆ is 81, and F ₇ is 81 , F ₈ is 80 and F ₉ is 79, the average value of luminance is 82, and the luminance value of area E is 82.
[0015]
Thereafter, as shown in FIGS. 6 and 8, the maximum value of the luminance difference between the adjacent areas E and E (hereinafter referred to as the first value), and the maximum luminance value and the minimum luminance value in all the areas E. A difference (hereinafter referred to as a second value) is obtained to determine whether or not a predetermined non-defective product determination condition is satisfied. Here, the predetermined non-defective product determination condition is: first value <first determination value and second value <second determination value. The first determination value and the second determination value are predetermined values set according to the object to be inspected (annular rubber seal member). The condition for determining a defective product is: first value ≧ first determination value or second value ≧ second determination value.
[0016]
More specifically, for example, in FIG. 6, it is assumed that the inspection region 9 is composed of four areas E ₁ , E ₂ , E ₃ , E ₄ , the luminance value of the area E ₁ is 155, and the area E ₂ It is assumed that the luminance value is 150, the luminance value of area E ₃ is 140, and the luminance value of area E ₄ is 143. Further, it is assumed that the first determination value is set to 20 and the second determination value is set to 50. In this case, the difference between the areas E ₁ and E ₂ is 5, the difference between the areas E ₂ and E ₃ is 10, the difference between the areas E ₃ and E ₄ is 3, and the first value is 10. Since the maximum luminance value is 155 and the minimum luminance value is 140, the second value is 15. Accordingly, the first value 10 <the first determination value 20 and the second value 15 <the second determination value 50 are satisfied, and it is determined that the non-defective product determination condition is satisfied.
[0017]
Further, as shown in FIG. 9 and FIG. 10, when the chip 11 and the burr 10 exist, the non-defective product determination condition is not satisfied (the defective product determination condition is satisfied). For example, in FIG. 9, the luminance values and the first and second determination values of the areas E ₁ , E ₃ and E ₄ are the same (as described in FIG. 6), and the luminance value of the area E ₂ is 60. Then, the difference between the areas E ₁ and E ₂ is 95, the difference between the areas E ₂ and E ₃ is 80, the difference between the areas E ₃ and E ₄ is 3, and the first value is 95. Since the maximum luminance value is 155 and the minimum luminance value is 60, the second value is 95. Accordingly, the first value 95 ≧ first determination value 20 or the second value 95 ≧ second determination value 50 is satisfied, and it is determined that the defective product determination condition is satisfied (the non-defective product determination condition is not satisfied). . That is, as shown in FIG. 8, it is determined that the product is defective.
[0018]
On the other hand, in FIG. 10, the luminance values and the first and second determination values of the areas E ₁ , E ₃ , E ₄ are the same (as described in FIG. 6), and the luminance value of the area E ₂ is 170. Then, the difference between the areas E ₁ and E ₂ is 15, the difference between the areas E ₂ and E ₃ is 30, the difference between the areas E ₃ and E ₄ is 3, and the first value is 30. Since the maximum luminance value is 170 and the minimum luminance value is 140, the second value is 30. Accordingly, the first value 30 ≧ the first determination value 20, and it is determined that the defective product determination condition is satisfied (the non-defective product determination condition is not satisfied). That is, as shown in FIG. 8, it is determined that the product is defective.
[0019]
In this way, it is determined whether or not a predetermined non-defective product determination condition is satisfied, and if it is determined that the non-defective product determination condition is satisfied, an annular rubber seal member is attached to the camera 3 as shown in FIGS. 7 is turned, and the camera 3 sequentially captures partial images of partial arcs of the circumference adjacent to the rubber seal member 7.
[0020]
That is, the rotary table 4 is intermittently driven to rotate the uni-piston 1 to sequentially capture partial images of the next partial arc of the lip 2 (similar to the above), and whether or not the non-defective product determination condition is satisfied. It is determined repeatedly. FIGS. 11A to 11G show a state in which the uni-piston 1 rotates intermittently and other partial images of the lip 2 are sequentially taken. In this way, if the lip 2 makes one revolution, the non-defective product determination condition is satisfied for the entire circumference of the lip 2, and it is determined that the lip 2 is a good product as shown in FIG. (At this time, it is also preferable to move and adjust the camera 3 (not shown) in the radial direction so that the captured image 6 comes near the middle of the screen 5 ).
[0021]
The present invention is not limited to the embodiments described above, for example, although the annular rubber seal member 7 in this embodiment has been described a test method when deformed into an oval shape, deformed into irregular circular rotation Although it may be installed on the table 4, the rubber seal member 7 having such a distorted circular shape can be reliably inspected with accuracy.
[0022]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0023]
Even if the circular rubber seal member 7 is elastically deformed into an elliptical shape or a distorted circular shape as well as a perfect circle, it can be easily and accurately inspected. Further, even the large-diameter annular rubber seal member 7 can be inspected easily because the partial images are taken in sequentially. Further, if the relative solid state imaging device camera 3 to wound handed an annular rubber seal member 7, even if there is misalignment between the center and the turning center of the rubber seal member 7 no problem, possible to simplify the structure of the inspection apparatus Can do. In addition, the inspection accuracy can be remarkably improved as compared with the prior art.
[0024]
Furthermore, the structure of the inspection apparatus can be further simplified. That is, rather than turning the solid-state imaging device camera 3 along the circumference of the annular rubber seal member 7, it is possible to simplify the structure by turning the annular rubber seal member 7 side.
[Brief description of the drawings]
FIG. 1 is a simplified explanatory view showing a captured image obtained by an inspection method for an annular seal member of the present invention.
FIG. 2 is an explanatory diagram showing coordinates of three points on the circumference of a captured image.
FIG. 3 is a cross-sectional view showing a uni-piston having a lip on the outer peripheral edge.
FIG. 4 is an explanatory view showing a state in which light is applied to a lip.
FIG. 5 is an explanatory diagram showing a virtual circle passing through the coordinates of three points.
FIG. 6 is an explanatory diagram showing a state in which a plurality of areas are set and arranged along a virtual circle.
FIG. 7 is an explanatory diagram showing a plurality of pixels constituting an area.
FIG. 8 is a flowchart.
FIG. 9 is an explanatory diagram showing an inspection state when a chip exists.
FIG. 10 is an explanatory diagram illustrating an inspection state when a burr exists.
FIG. 11 is an explanatory diagram showing a state in which other partial images of the annular rubber seal member are sequentially captured .
[Explanation of symbols]
1 Uni-piston
2 Lips
2a End face 3 Solid-state image sensor camera
4 Rotary table 6 Captured image 7 Circular rubber seal member 8 Virtual circle 9 Inspection area
12 lighting lamp
A, B, C point E area F pixel O center r radius

Claims (1)

In the inspection method in which the lip (2) formed on the outer peripheral edge of the uni-piston (1) is inspected as an annular rubber seal member (7), the uni-piston (1) is placed on the horizontal rotary table (4). Installed, irradiated light in the horizontal direction from the outer peripheral side to the inclined end surface (2a) of the lip (2) by the illumination lamp ( 12 ), and reflected by the end surface (2a) of the lip (2) The solid-state image sensor camera (3) is arranged so that light is received by the upper solid-state image sensor camera (3), and the rotary table (4) is intermittently swiveled so that the solid-state image sensor camera (3 ) To capture the partial image of the circumference of the end face (2a) of the lip (2) and obtain the coordinates of three points (A, B, C) on the circumference of the captured image (6) . Calculate the center (O) position and radius (r) of the virtual circle (8) using the coordinates and the equation of the circle. The virtual circle (8) passing through the coordinates is set, and a plurality of areas (E) composed of a plurality of pixels (F) having multi-level luminance information are set and arranged along the virtual circle (8). The inspection area (9) is set, the average value of the luminance in each area (E) of the inspection area (9) is calculated to obtain the luminance of each area (E) , and then the adjacent area (E) The maximum difference in brightness and the difference between the maximum brightness value and the minimum brightness value in all areas (E) are determined to determine whether or not a predetermined non-defective product determination condition is satisfied. The rotary table (4) is intermittently swiveled to sequentially capture other partial images of the circumference of the end surface (2a) of the lip (2), and the non-defective product determination condition is satisfied through the same process. or determines, for the entire circumference of the lip (2) as the annular rubber seal member (7) Method of inspecting an annular rubber seal member characterized by determining a non-defective satisfies the serial good determination condition.

Images