JP2981762B2 - O-ring inspection method - Google Patents

Description

The present invention relates to an O-ring inspection method.

[Conventional technology]

Generally, an O-ring used as a sealing material for fluid equipment and pipes is molded by heating and pressurizing in a mold and vulcanizing, and burrs protrude from the inner and outer peripheral surfaces thereof. If a notch or a notch is present, it becomes a defective product that cannot exhibit sealing performance.

Heretofore, such an inspection of the appearance of the O-ring has been directly visually performed by an operator.

[Problems to be solved by the invention]

In the above-described conventional inspection method, the operator has been overlooked, and the working efficiency has been extremely low.

The object of the present invention is to automatically and efficiently inspect the presence and absence of burrs and notches on the inner and outer peripheral surfaces, which greatly affect the sealing performance, as an appearance inspection of the O-ring,
The purpose is to do.

[Means for solving the problem]

The O-ring inspection method according to the present invention captures an image of an O-ring by a solid-state imaging device camera, performs image processing on the image, binarizes the image, and forms concentric double circles corresponding to the outer circumference and the inner circumference of the O-ring, respectively. When the center of the window and the center of gravity of the binarized O-ring image are matched with each other, whether the outer circumference and the inner circumference of the O-ring image are within a predetermined width of the outer circle and the inner circle of the circular window is determined. This is a method of determining pass / fail.

(Operation)

By binarizing the image of the O-ring,
Processed as numerical data, making it easier to process. That is, after that, the displacement can be easily corrected so that the center of gravity of the binarized O-ring image coincides with the center of the window.

Since the window is a double circular window composed of concentric outer and inner circles, burrs and notches on the outer and inner circumferences of the O-ring (image) can be simultaneously checked.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

In the block diagram shown in FIG. 5, reference numeral 1 denotes an O-ring as an object to be inspected, which is placed on the upper surface of the translucent glass 2 in the inspection zone A, and is illuminated from below (as in FIG. 3). 3
The O-ring 1 is located just above the O-ring 1.
Is provided with a solid-state image sensor (CCD) camera 4 for capturing a transmitted image.

Reference numeral 5 denotes a sensor that detects that the O-ring 1 is supplied by a method described later and exists on the translucent glass 2. 6
Is a flash control circuit, which sends a signal to be emitted to the illuminator 3 when a detection signal from the sensor 5 is input.

Reference numeral 7 denotes an image processing unit that performs image processing on the video captured by the solid-state imaging device camera 4 and binarizes the video.

Reference numeral 38 denotes an operation unit, which is used to create a window W by inputting dimensions of a double circular window W composed of concentric outer circles 8 and inner circles 9 with operation keys as shown in FIG.

Reference numeral 10 denotes an arithmetic means, which is a binarized O-ring image G
(See FIGS. 7 and 8) The center of gravity measurement function of calculating the center of gravity O ₁ numerically, and the center O _{0 of the} window W as a reference pattern and the center of gravity O ₁ of the O-ring image G And a misalignment correction function for matching. A display means 11 displays a double circular window W (as shown in FIGS. 7 and 8), an O-ring image G, and the like. Further, the arithmetic means 10 makes the center of gravity O ₁ of the O-ring image G coincide with the center O ₀ of the double circular window W (as shown in FIG. 8), and The inner circumference 13 has predetermined widths w ₁ and w of the outer circle 8 and the inner circle 9 of the window W.
_It also has a function of judging pass / fail based on whether it is within ₂ .

In FIG. 8, the center O ₀
And the center of gravity O ₁ coincide with each other and overlap each other, a burr B and a notch C exist on the outer periphery 12 of the binarized O-ring image G, and the burr B also exists on the inner periphery 13. Although notches C illustrates the case where the present, burr B of the outer periphery 12, protrudes outward beyond the peripheral line 8a of the outer circle (window) 8 having a predetermined width w _1. As a method of setting the criteria for pass / fail judgment, the outer line 8a
Can be set to be determined to be defective if it touches, for example, in FIG. 9, the area of the protruding portion 14 is
^{It is} also desirable to set the value to ² or less. In the latter case, the dots are divided into extremely small grids.
It is preferable to calculate the area (the number of pixels) of the protruding portion 14 by counting the number of pixels.

Further, At a Figure 8, notches C of the outer periphery 12 enters inwardly beyond the inner circumferential line 8b of the outer circle (window) 8 having a predetermined width w _1. Further, burr B and the notch C of the inner peripheral 13, beyond each of the inner circle (window) 9 inner peripheral line 9b and the outer peripheral line 9a of a predetermined width w _2,
Enter the inside and outside respectively. The quality judgment at this time is made in the same manner as in the case of the burr B on the outer periphery 12 described above.

According to the O-ring inspection method of the present invention, as shown in FIG. 5 and the flowchart shown in FIG. The center O ₀ of the double circular window W is binarized by image processing by the image processing means 7 and the center of gravity O _{1 of the} binarized O-ring image G is made coincident. The outer circumference 12 and inner circumference 13 of G are double circular windows W
Whether they are within the predetermined widths w ₁ and w ₂ of the outer circle 12 and the inner circle 13
This is a method of judging pass / fail based on the above-mentioned case where a small area (small number of grid dots) is allowed.

In FIG. 5, after that, a command signal 15 based on the quality judgment is sent from the calculating means 10 to the actuator 16 of the sorting / discharging means P, and the actuator 16 replaces the O-ring 1 after inspection with a non-defective product. And the defective products are discharged in different discharge directions. The dimensions (and widths w ₁ and w ₂ ) of the outer circle 8 and the inner circle 9 of the window W are determined in advance from the design values of the O-ring 1 to be inspected. Alternatively, it may be determined by sampling a large number of normal products.

Next, FIG. 1 is a schematic plan view of the whole O-ring inspection apparatus, and 17 is a parts feeder, in which the O-rings are aligned and sent from the supply path 18 as shown by the arrow E.

In FIG. 1 and FIG. 2 showing a main part thereof, a fluid cylinder 21 having a plate-shaped L-shaped pusher 20 provided with a gate 19 at a downstream end of a supply path 18 and reciprocating in an orthogonal direction is shown in FIG. It is attached as follows. The translucent glass 2 is provided at a position where the pusher 20 extends like an imaginary line, and another fluid cylinder 23 having a plate-shaped L-shaped stopper 22 is provided substantially on the same line as the direction in which the cylinder 21 extends. If they are provided and extended so as to approach each other, the O-rings 1 can be set at the central position of the translucent glass 2 (one by one) as shown by the imaginary line in FIG. Thereafter, the inspection is performed as described with reference to FIG.

Reference numeral 24 denotes an air blow discharge port. When the inspection is completed, air is blown out as indicated by an arrow F to blow off the O-ring 1 to the discharge port 24.

2, a sensor 25 is provided on the downstream side (left side) of the gate 19, and detects that the O-ring 1 has been sent to the position of the pusher 20 through the gate 19. This sensor 25 is disposed in an inclined slit 26 formed in the pusher table, and can be adjusted according to the size of the O-ring 1. When the sensor 25 detects that the O-ring 1 has been pushed into the pusher 20, the cylinder 21 extends and sends the O-ring 1 to the inspection zone A.

Next, FIG. 4 is an enlarged partial cross-sectional view of the left side of FIG. 1 and specifically shows an example of the sorting and discharging means P.
That is, the lower opening 27 of the chute 27 forming the discharge port 24
A good / defective product classification block 28 reciprocating with the actuator 16 such as a cylinder as indicated by arrows H and K is provided so as to correspond to the components a and b alternately. One passage 29 of this block 28 is used for a non-defective product and is freely communicated with a non-defective product discharge passage 30, while another passage 31 is used for a defective product and is used for a defective product discharge passage.
Communication with 32 is allowed.

When the inspection is completed, the actuator 16 is operated by the command signal 15 from the calculating means 10 shown in FIG.
28 is switched to one of the two positions, blown off by air blow, reaches the discharge port 24, falls, and
It falls from any of 9,31 and is sorted into good and bad products.

FIG. 10 is a plan view showing an overall modified example, in which the parts feeder 17 and the supply path 18 are the same, but the downstream end thereof is a turntable that rotates continuously or intermittently as indicated by an arrow M.
The turntable is provided with at least a semi-transparent glass plate (or a plastic plate), and O-rings 1... Are successively placed on the turntable and rotated. In the inspection zone A, non-defective products and defective products are identified by the inspection method already described with reference to FIG. 3 and FIGS. Then, along the outer periphery of the turntable 33, a defective product discharging path
32 and a good product discharge path 30 are provided. The former is also disposed near the inspection zone A, and is provided with a guide plate 34 that reciprocates in the radial direction by the actuator 16, and is used as the sorting and discharging means P. In the case of a non-defective product, it retreats to the position indicated by the solid line. In addition, 35 is a fixed guide plate.

The O-ring image G is shown in the flowchart of FIG.
The outer circumference 12 and the inner circumference 13 are sequentially determined. However, the outer circumference 12 may be determined first with the inner circumference 13 first, and, of course, may be determined simultaneously. Window W
If the O-ring image G slightly touches (cuts) the outer peripheral lines 8a and 9a and the inner peripheral lines 8b and 9b, it may be determined that the O-ring image G is defective, but the intrusion of a small number of pixels (see FIG. 9) is allowable. It may be preferable to set such that it is determined that

〔The invention's effect〕

According to the present invention, it is possible to automatically and accurately determine the appearance of the O-ring by the above-described configuration, and it is possible to inspect a large number of O-rings with high efficiency.

[Brief description of the drawings]

1 is a simplified plan view showing an example of an apparatus used in the present invention, FIG. 2 is an enlarged view of a main part of FIG. 1, FIG. 3 is a side view of the main part, and FIG. FIG. 5 is a block diagram showing an embodiment of the present invention, FIG. 6 is a flowchart, FIG. 7, FIG. 8 and FIG. 9 are explanatory diagrams, and FIG. It is a simplified plan view of an example. 1 ...... O-ring, 4 ...... cameras, 8 ...... outer circle, 9 ...... inside a circle, 12 ...... periphery, 13 ...... inner, w _1, w ₂ ...... width, W ...... 2
Heavy circular window, G ... O-ring image, O ₀ ... center,
O ₁ ... the center of gravity.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 21/84 G01N 21/88 F16J 15/00 G01B 11/24 H04N 7/18

Claims (1)

(57) [Claims] An image of an O-ring is captured by a solid-state imaging device camera, the image is image-processed and binarized, and the center of a concentric double circular window corresponding to the outer circumference and the inner circumference of the O-ring, respectively; In a state where the center of gravity of the binarized O-ring image is matched, whether the O-ring image is outside or inside the predetermined width of the outer and inner circles of the circular window is determined as to whether the O-ring image is good or not. An O-ring inspection method, characterized in that: