JPH04102050A - Method for inspecting o-ring - Google Patents

Abstract

PURPOSE:To automatically inspect with high efficiency and high accuracy by binary coding an image of an O-ring and making comparison as to whether its outer periphery and its inner periphery are within predetermined ranges of an outer circle and an inner circle of a double-circle window as a reference pattern. CONSTITUTION:When an O-ring 1 is supplied onto a semitransparent glass piece 2, a CCD camera 4 acquires its image. This is subjected to image processing by an image processing means 7 and binary coded. Sizes of a double-circle window comprising concentric outer and inner circles are input from a control unit 38 to the processing means 7 to create a window as a reference pattern. An arithmetic means 10 displays 11 the center of gravity of the ring image and the center of the window while the centers are aligned with each other and also determines whether the ring is good or defective as to whether an outer periphery and an inner periphery of the ring image are within predetermined ranges of the outer circle and the inner circle of the window. For example, the number of pixels outside the predetermined range is calculated and when the value is a predetermined value or lower, the ring is determined to be good. An actuator 16 of a selecting and discharging means P carries the rings 1 in different directions by an instruction signal 15 depending on whether it is good or defective.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an O-ring inspection method.

[Prior Art] Generally, O-rings used as sealing materials for fluid equipment, piping, etc. are molded by heating and pressurizing in a mold and vulcanizing. If there are protruding holes or notches, the product will be defective and cannot exhibit its sealing performance.

Conventionally, the appearance of such an O-ring has been inspected directly by an operator.

(Problem to be solved by the invention) In the conventional inspection method described above, there is a possibility of operator oversight.
In addition, work efficiency was extremely low.

The purpose of the present invention is to automatically and efficiently inspect the appearance of O-rings for the presence of cracks and notches on the inner and outer circumferential surfaces, which have a great impact on sealing performance. With the goal.

[Means to solve the problem]

The O-ring inspection method according to the present invention captures an image of an O-ring with a solid-state image sensor camera, processes the image, and then performs two
The center of the concentric double circular window corresponding to the outer and inner circumferences of the 0-ring is aligned with the center of gravity of the binarized 0-ring image, and the outer and inner peripheries of the 0-ring image are This method determines whether the window is good or bad based on whether or not the window is within a predetermined width between the outer circle and the inner circle of the circular window.

[For production]

By converting the O-ring image into a binary image, it can then be processed as numerical data, making it easier to process. That is, after that, the positional deviation 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 consisting of a concentric outer circle and an inner circle, it is possible to simultaneously check for burrs and notches on the outer and inner circumferences of the O-ring (image).

〔Example〕

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

In the block diagram shown in FIG. 5, 1 is an O-ring as an object to be inspected, which is placed on the upper surface of the semi-transparent glass 2 in the inspection zone A, and is illuminated from below by an illuminator (as shown in FIG. 3). A solid-state imaging device (CCD) camera 4 is provided directly above the O-ring 1 to capture a transmitted image of the O-ring 1.

Reference numeral 5 denotes a sensor that detects that the O-ring 1 is supplied by a method described later and is present on the semi-transparent glass 2. A strobe control circuit 6 sends a signal to the illuminator 3 to emit light when a detection signal from the sensor 5 is input.

Reference numeral 7 denotes an image processing means that processes the video captured by the solid-state image pickup device camera 4 and converts it into a binarized image.

Reference numeral 38 denotes an operation unit, and as shown in FIG. 7, dimensions of a double-positioned window W consisting of a concentric outer circle 8 and an inner circle 9 are input using operation keys to create a window W. .

10 is a calculation means, which calculates the binarized O-ring image G (
The center of gravity measurement function numerically calculates the center of gravity 01 (see Figures 7 and 8), and the center 0° of the window W as a reference pattern matches the center of gravity OI of this O-ring image G. Equipped with positional deviation correction function. 11 is a display means (as shown in FIGS. 7 and 8) 2
Displays today's form window W1, 0 ring image G, etc. Furthermore, the calculation means 10 calculates the center of gravity 0 of the 0 ring image G (as shown in FIG. 8). The 0 ring image G is aligned with the center Os of the double-mounted window W.
It also has a function to determine whether the window W is good or bad depending on whether the outer periphery 12 and the inner periphery 13 of the window W are within a predetermined width Wl, W= of the outer circle 8 and the inner circle 9 of the window W.

To explain in more detail in FIG. 8, the center 0.
With the center of gravity 01 coinciding and overlapping, there are burrs B and notches C on the outer periphery 12 of the binarized 0-ring image G, and burrs B and notches C also exist on the inner periphery 13. Although the case where C exists is illustrated, the burr B on the outer periphery 12 protrudes outward beyond the outer periphery line 8a of the outer circle (window) 8 having a predetermined width W. The method for setting standards for determining pass/fail is as follows:
It can be set so that if it touches this outer circumferential line 8a, it is determined to be defective, but it is also desirable to set it so that, for example, in FIG. In the latter case, it is preferable to calculate the area (number of pixels) of the protruding portion 14 by counting the dots (pixels) divided into extremely small grids.

In addition, in FIG. 8, the notch C on the outer periphery 12 has a predetermined width W1.
It goes inward beyond the inner circumferential line 8b of the outer circle (window) 8. Moreover, the tension B and the notch C of the inner circumference 13 have a predetermined width w.
The pass/fail judgment at this time is the same as in the case of the burr B on the outer periphery 12 described above. , do it.

The O-ring inspection method of the present invention includes the above-mentioned FIG. 5, etc., and
As is clear from FIG. 6, which is a flowchart,
The solid-state image sensor camera 4 captures an image of the O-ring l, and the image processing means 7 processes the image to convert it into 2 bonds.
The center O0 of the superimposed window W and the center of gravity 0 of the binarized O-ring image G are made to match, and in that state, the outer periphery 12 and inner periphery 13 of the O-ring image G become the double superimposed window. This is a method of determining pass/fail based on whether or not it is within the predetermined width W+ of the outer circle 12 and inner circle 13 of W, including the case where the above-mentioned small area (a small number of grid dots) is allowed. .

In FIG. 5, the calculation means 10 then sends a command signal 15 based on the pass/fail judgment to the actuator 16 of the sorting and discharging means P, and this actuator 16 selects the inspected O-ring 1 as a non-defective item. and defective products, they are transported in different discharge directions. Also, the outer circle 8 of the window W.
The dimensions of the inner circle 9 (and the width W,,wt) are 0 to be inspected.
Determine in advance from the design value of ring 1. Alternatively, it is better to determine by sampling a large number of normal crystals.

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

In FIG. 1 and FIG. 2 showing the main parts thereof, a gate 19 is provided at the downstream end of the supply path 18, and a fluid cylinder 21 having a plate-shaped bushing 20 that reciprocates in the orthogonal direction is shown. It is attached as follows. The semi-transparent glass 2 is provided at a position where the bushing 20 extends like an imaginary line,
Further, another fluid cylinder 23 having a plate-like L-shaped stopper 22 is provided approximately on the same line as the extending direction of this cylinder 21, and when extended so as to approach each other, as shown by the imaginary line in FIG. The O-rings 1 (one at a time) can be set at the center of the translucent glass 2. Thereafter, the inspection is performed as explained in FIG.

24 is an air blower outlet, and when the inspection is completed, air is blown out as shown by arrow F, and the O-ring 1 is removed from the outlet 24.
Blow away.

In addition, in Fig. 2, on the downstream side (left side) of game 9,
A sensor 25 is provided to detect the passage of the O-ring 1 through the gate 19 to the position of the bushing 20. This sensor 25 is arranged in an inclined slit 26 formed in the bushing table and can be adjusted according to the dimensions of the O-ring 1. By this sensor 25, the O ring 1
When it is detected that has been pushed out into the butsusha 20,
The cylinder 21 is expanded and the O-ring 1 is delivered to the inspection zone A.

Next, FIG. 4 is an enlarged partial sectional view of the left side of FIG. 1, specifically showing an example of the sorting and discharging means P. In other words, good products are reciprocated by an actuator 16 such as a cylinder as shown by the arrow H9 so as to alternately correspond to the lower openings 27a of the chute 27 forming the discharge port 24.
A defective product classification block 28 is provided. One passage 29 of this block 28 is used for non-defective products and can be freely communicated with a non-defective product discharge path 30, while another passage 31 is used for defective products and can be freely communicated with a defective product discharge path 32.

When the inspection is completed, the actuator 16 is actuated by the command signal 15 from the calculation means 10 shown in FIG. 24, they fall, fall from either passage 29 or 31, and are sorted into good and defective products.

FIG. 10 shows an overall modification in a plan view, in which the parts feeder 17 and the supply path 18 are the same, but the downstream end thereof is provided with a turntable 33 that rotates continuously or intermittently as shown by arrow M. The outer periphery of this turntable is made of at least a translucent glass plate (or plastic plate), and objects to be inspected, such as O-rings, are placed one after another and rotated. In the inspection zone A, non-defective products and defective products are identified by the inspection method already described in FIG. 3 and FIGS. 5 to 9. A passage 32 and a good product discharge passage 30 are provided. The former is arranged near the inspection zone A, and is provided with a guide plate 34 that is reciprocated in the radial direction by an actuator 16 to form a sorting and discharging means P. In the case of a good product, it retreats to the position indicated by the solid line, and in the case of a defective product, it moves forward as shown in the imaginary line, and can be sorted into a non-defective product discharge path 30 and a defective product discharge path 32, respectively. Note that 35 is a fixed guide plate.

In the flowchart of FIG. 6, the outer circumference 12 and inner circumference 13 of the O-ring image G are sequentially determined, but the inner circumference 13 may be determined first and the outer circumference 12 later.
You are free to decide to judge at the same time. Also, if the O-ring image G slightly touches (cuts) the outer circumferential lines 8a, 9a and inner circumferential lines 8b, 9b of the window W, it may be determined to be defective, but a small number of pixels intrude (see Fig. 9). ) may be preferably set so that it is determined to be within the permissible range.

〔Effect of the invention〕

With the above-described configuration, the present invention can realize highly accurate and automatic selection of the appearance of O-rings to determine whether they are good or bad.
Rings can now be inspected with high efficiency.

[Brief explanation of drawings]

Fig. 1 is a simplified plan view showing an example of the device used in the present invention, Fig. 2 is an enlarged view of the main part of Fig. 1, Fig. 3 is a side view of the main part, and Fig. 4 is an enlarged view of the main part - fractured surface. 5 is a block diagram showing one embodiment of the present invention, FIG. 6 is a flowchart diagram, FIGS. 7, 8, and 9 are explanatory diagrams, and FIG. 10 is a modification in place of FIG. 1. FIG. 3 is a simplified plan view of an example. 1...0 ring, 4...camera, 8...outer circle, 9
...Inner circle, 12...Outer circumference, 13...Inner circumference, W...
wt...width, W...double circular window, G...
0 ring image, 0. ...Center, 0. ...center of gravity. Patent applicant: Mitsubishi Cable Industries, Ltd. Figure 8, 99, Figure 10

Claims (1)

[Claims] 1. Capture an image of the O-ring with a solid-state image sensor camera, process the image and convert it into a binary image, and then identify the center of a concentric double circular window corresponding to the outer and inner periphery of the O-ring, respectively. The quality of the O-ring image is determined based on whether the outer circumference and inner circumference of the O-ring image are within a predetermined width of the outer circle and the inner circle of the circular window, with the center of gravity of the O-ring image aligned with the center of gravity of the O-ring image. O-ring inspection method.