JPH1048150A - Seal-inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out an automatic visual check of a ring-shaped seal smoothly and efficiently without reversing the seal, by illuminating a transparent plate sent with the seal loaded thereon from the front side and the rear side, and processing images of a front face and a rear face of the seal. SOLUTION: A circular transparent plate 4 loading ring-shaped seals S... is continuously driven and rotated by a motor around an axial center L (direction of an arrow R). CCD cameras 10, 10 are set above and below the transparent plate 4 to face each other, each of which has an illumination lamp. The transparent plate 4 is illuminated from a front face and a rear face thereof, and bright ring-shaped images formed by the reflected illumination at a front and a rear faces of the seal S are processed, thereby visually inspecting the seal, e.g. damage or the like of the seal. Defective product, discharge nozzles 7a, 34a are provided which gush the air and blow the seal S judged to be defective in the visual inspection to an outer diametrical direction. Moreover, two outer dimension-measuring instruments 31, 32 of a laser type are arranged to obtain an average value of outer diameters of the seals S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection device for an annular seal such as an O-ring.

[0002]

2. Description of the Related Art Inspections of annular seals for burrs, chips, surface scratches, etc. are performed by sequentially illuminating the seals with a conveyor and fetching the seal images with a solid-state imaging device camera or the like. A method is known in which the image is processed, inspected, and automatically performed. However, conventionally, only one side (one side) of the seal is generally inspected. However, if the inspection of the surface flaw is not performed on both sides, the reliability is deteriorated (the flaw is overlooked). In view of this, the present inventors have proposed a device capable of inspecting both front and back surfaces of a seal in Japanese Patent Application No. 68633/1995.

That is, the apparatus comprises a first conveyor on which an O-ring is placed and sequentially fed, and a white ring-shaped portion which is illuminated from a direction perpendicular to the surface of the first conveyor and reflected by the O-ring surface. A first inspection means for processing an image to detect a surface flaw of the O-ring, a reversing means provided at a rear end of the first conveyor for reversing the O-ring sequentially sent, and a reversing means. A second conveyor for receiving and feeding the inverted O-ring, and illuminating from a direction orthogonal to the surface of the second conveyor to image-process an image of a white ring-shaped portion reflected on the O-ring surface; A second inspection means for detecting a surface flaw of the O-ring, wherein the reversing means comprises a reversing guide body having a curved concave surface surrounding the U-turn portion on the rear end side of the first conveyor at a predetermined interval. I had it.

[0004]

However, if the seal has a small diameter and a small thickness (for example, an outer diameter of 5.4 mm and a thickness of 0.6 mm), the U-turn portion of the above-described conveyor and the curved concave surface of the reversing guide body are required. In between, the seal is caught or clogged, stagnates, and the appearance (surface flaw) inspection of the front and back surfaces cannot be performed smoothly.

Conventionally, dimensional inspections such as outer diameters of seals, for which dimensional tolerances are strictly required (eg, 0.01 mm, etc.), are conventionally measured only in one direction using a laser external measuring instrument or the like.
Although pass / fail was determined, the seal made of an elastic material such as rubber generally had a problem that a slight deformation (not a perfect circle) was present and a measurement error was large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a seal inspection apparatus which can automatically and smoothly perform an external appearance inspection of a seal without inversion and can perform a high-precision dimensional inspection. It is in.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a transparent plate on which an annular seal is placed and fed, and a light-colored ring formed by applying illumination from the front side of the transparent plate and reflecting off the seal surface. 1st image processing of the image of the part to inspect the appearance such as surface scratches
Inspection means, and second inspection means for illuminating from the back side of the transparent plate and performing image processing on an image of a light-colored ring-shaped portion reflected on the back side of the seal to perform appearance inspection such as surface scratches. ing.

[0008] An X-direction external measurement device and a Y-direction external measurement device for measuring the outer diameter along the X-axis and the Y-axis, respectively, of the rectangular coordinate system having the origin at the center point of the annular seal; External measurement and Y
Calculating means for calculating an average value of the outer diameter in the X direction and the outer diameter in the Y direction measured by the out-of-direction measuring device. The transparent plate is a turntable that is driven to rotate about a vertical axis.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on the illustrated embodiments.

In the plan view of FIG. 1, the front view of FIG. 2, the simplified perspective view of the main part of FIG. 3, and the structure explanatory view of the main part of FIG.
Is a circular transparent plate that is driven to rotate by placing an annular seal S on the upper surface of the outer peripheral edge. The transparent plate 4 is a so-called turntable that is rotated around a vertical axis L by a motor (not shown). (In the direction of the arrow R).
A seal S made of an elastic material such as a ring, a square packing, a U packing or the like is placed on the upper surface of the outer peripheral edge to continuously feed. The material of the transparent plate 4 can be glass or transparent plastic.

Reference numeral 1 denotes first inspection means provided near the outer peripheral edge of the transparent plate (turntable) 4, which is illuminated from the surface (upper surface) side of the transparent plate 4 and reflected on the surface of the seal S. Image of the bright colored ring-shaped portion 21 (see FIG. 8 described later)
Is subjected to image processing, and an appearance inspection such as a surface scratch is performed. The illumination is applied from above the transparent plate 4 in a direction perpendicular to the surface of the transparent plate 4 (vertically below).

Reference numeral 2 denotes a second inspection means provided near the outer periphery of the transparent plate (turntable) 4. In the illustrated example, the second inspection means 2 is disposed immediately below the first inspection means 1 described above.
Illuminate through the transparent plate 4 from the back (lower) side of
The image of the light-colored ring-shaped portion 21 reflected on the back surface of the seal S (see FIG. 8) is subjected to image processing, and an appearance inspection such as a surface flaw is performed. The illumination is applied from below the transparent plate 4 in a direction perpendicular to the back surface of the transparent plate 4 (vertically upward). In the illustrated example, a case is shown in which the first and second inspection units 1 and 2 are arranged in the same place so that the irradiation optical axes of the first inspection unit 1 and the second inspection unit 2 substantially coincide with each other. Since the second inspection means 2 inspects through the transparent plate 4, it is possible to inspect both sides without inverting the seal S upside down as in the related art.

By the way, seals S... Are successively sent from the parts feeder 5 to the upper surface of the outer peripheral edge of the rotating transparent plate 4 via the straight-ahead feeder 3. 8 thus indicates a feed. 6 is slightly downstream from the supply unit 8───rotation direction R
Is a positioning guide for the seal S disposed on the downstream side of the transparent plate 4. Immediately after being fed by the inclined guide portion, the seal S is moved from the outer peripheral edge of the transparent plate 4 to the inner side by a certain distance.
Is moved so that the above-mentioned appearance inspection and the outer diameter dimension inspection described later can be reliably performed.

The first and second inspection means 1 and 2 use this guide 6
Is disposed on the downstream side (downstream side in the rotation direction R) of the
Further, a poor appearance discharge container 7 for discharging and storing the seal S determined to be defective in the visual inspection is disposed downstream thereof. The defective appearance discharge container 7 has a defective product discharge nozzle 7a that intermittently blows air to blow out defective external products in the outer diameter direction.

Next, on the downstream side of the container 7, an X-direction outside measuring instrument 31 and a Y-direction outside measuring instrument 32 are sequentially arranged. That is,
Since the annular seal S is an elastic material, it is not a perfect circle, but is often slightly deformed into an ellipse or the like. The X-axis and the X-axis when virtual coordinates having the center point of the annular seal S as the origin are imagined.
The outer diameter dimension along the Y axis is measured in the X-direction
It is measured by an out-of-direction meter 32. FIG. 4 shows a calculating means 33 such as a personal computer for calculating the average value of the X-direction outer diameter and the Y-direction outer diameter thus measured.

Next, a defective-size discharge container 34 and a non-defective shooter 35 are sequentially arranged downstream of the Y-direction outside measurement device.
The defective product discharge container 34a is a defective product discharge nozzle 34a that intermittently blows air to blow out defective products in the outer diameter direction.
Having. The non-defective shooter 35 stores all of the unremoved and unrecognized defective products, which are not discharged (removed). The non-defective shooters 35 are configured so as to be classified and stored according to the size range of the seal S as desired.

Next, an example of a specific configuration of the first inspection means 1 and the second inspection means 2 and its operation (inspection method) will be described. 4 and FIGS. 1, 2, and 3, solid-state imaging device cameras 10, 10 are provided above and below the transparent plate 4 so as to face each other, and are coaxial with each of the cameras 10, 10. An epi-illumination lamp 11 is provided. Also, the camera is placed at an appropriate position with respect to the position of the seal S sequentially sent by the transparent plate 4.
To set (adjust) 10 and lamp 11, preferably X
The camera 10 and the lamp 11 are mounted on the YZ axis stage 9.
The optical axes of the upper and lower cameras 10 and 10 substantially coincide with each other, and images are simultaneously captured at the same location on the rotary transparent plate 4 (as a turntable). The circumferential position where the camera 10 is provided is the appearance inspection position.

Although not shown, a sensor is provided at this appearance inspection position, and detects a seal S placed on the transparent plate 4 and sent to output a detection signal. The detection signal of this sensor is shown in FIG. 4 by an asterisk (*), and the detection signal is input to the controller 16.

A controller 16 issues a signal for ejecting the discharge nozzle 7a of the defective appearance discharge container 7 downstream of the visual inspection position. That is, the solid-state imaging device camera (hereinafter sometimes referred to as a CCD camera) 10 is provided with an electronic shutter, and the shutter speed is extremely high, for example, 1/2000 sec. Is sent to the controller 16, the command signal from the controller 16 is sent to the (upper and lower) CCD cameras 10, 10 via the image processing means 17, and from the lamps 11, 11. The above CCD camera while irradiating light
At 10, 10, the seal S on the transparent plate 4 is photographed from both upper and lower (front and back) sides. (The back side is photographed through the transparent plate 4.)

As illustrated in FIG. 5, a lamp 11 is mounted so as to have an optical axis (horizontal horizontal direction) orthogonal to the optical axis on the tip lens side of each of the upper and lower CCD cameras 10, 10. Has a light source 12 such as a halogen lamp, a concave mirror 13 for converting into a parallel light beam, and a half mirror 15 disposed at a 45 ° inclination. The half mirror 15 has a light reflectance and a transmittance of 50% each, and changes the optical axis of the lamp 11 by 90 ° after reflection so as to coincide with the vertical optical axis of the CCD camera 10 (coaxial). Change). Such illumination having an optical axis coaxial with the optical axis of the CCD camera 10 is referred to as coaxial epi-illumination, and is applied to the seal S on the transparent plate 4 (as shown in FIG. 7, the light is reflected on both sides of the seal S, and the light transmitted through the half mirror 15 is transmitted to the CCD camera 10 as shown in FIG.
To the front lens side.

FIG. 11 shows another embodiment, in which the upper and lower CCD cameras 10 and 10 have no (normal) shutter function, and the light source 12 is a strobe. Associating the half mirror 15 with each of the CCD cameras 10 and 10 is the same as in FIG.
The vertical optical axes 38 and 39 on the 37 side are displaced by a small dimension ΔX. In this way, by shifting the vertical optical axes 38, 39 of the upper and lower CCD cameras 10, 10 by the small dimension ΔX, when inspecting the front and back of the seal S, there is no possibility that one of the seals S will be affected by the other light source. Is excellent. At this time, first, the front-side light source (strobe) 12 is caused to emit light, and an image of the front surface is captured. Immediately thereafter, the back-side light source (strobe) 12 is emitted and the image of the back surface is captured, and both images are processed. Good.

FIGS. 5 to 10 and 11 show, as an example, the case of an O-ring as the seal S. In the case of this O-ring, the light of the coaxial epi-illumination is sealed (as in FIGS. 5 and 7). S
In the vicinity of the top 18 and the bottom 18 'of the outer surface, the upper and lower CCD cameras 10 and
It is incident on 10.

As shown in FIG. 4, signals from the respective CCD cameras 10 are electrically connected so as to be sent to image processing means such as a microcomputer, and are also connected to a monitor 23 (described later).
The image processing means 17 and the monitor 23 are electrically connected so that an image can be displayed. An operation unit 22 is connected to the image processing unit 17.

In the case where the seal S is an O-ring and the image processing means is binarized, first, as shown in FIG. 5 and FIG.
When incident on 10 tip lenses, near the top of the O-ring surface
18 and the bottom 18 'are white, the inner peripheral edge 19 and the outer peripheral edge 20 of the O-ring.
Is binarized into black, and an O-ring image G having a light-colored (white) ring-shaped portion 21 is obtained as shown in FIGS. If a surface flaw exists near the top 18 (or bottom 18 '), the surface flaw 26 appears as black in the light-colored (white) ring-shaped part 21 as shown in FIG.

In the flowchart shown in FIG. 6 and the binarized image shown in FIG. 8, thereafter, the center of gravity O _{1 of the} binarized O-ring image G is sent to the image processing means 17 (FIG. 4). The center O _{2 of the} window W (preliminarily set by the input from the operation unit 22) is moved to match the center of gravity O ₁ with the center O ₂ .

This window W includes two burr detection windows W ₁ and W ₂ and two chip detection windows W ₃ and W 2.
_4, a concentric circle composed of one surface flaw detection window W _5, the window W and O-ring image G and the like are displayed on the monitor 23 (see FIG. 4).

FIG. 9 shows the center of gravity O of the O-ring image G.₁ And c
The center O of W_Two Are matched, and O
The outer periphery 27 and the inner periphery 28 of the ring image G are provided with burrs 24, respectively.
Chip 25 is present in the light (white) ring-shaped part 21
A case where the surface flaw 26 is present will be exemplified. O-ring image
Two windows W on the outer periphery 27 of G₁ , W_Three Corresponding
The burr 24 and the chip 25 on the outer periphery 27 are detected.
Book window w_Two , W _Four Corresponding to the burr 24 on the inner circumference 28
The chip 25 is detected, and the light-colored (white) ring-shaped part 21 is detected.
(W center in the width direction)_Five Is corresponding to the surface
The scratch 26 is detected.

More specifically, FIGS. 6, 9 and
At 10, the area on the window W is measured by the image processing means 17 (see FIG. 4) {that is, the number of white pixels and the number of black pixels on the window W are counted as shown in FIG. Compare with the pass / fail judgment reference value (pre-input),
Burrs 24, chips 25 or surface flaws 26 that exceed the allowable range
Is detected and determined, and the quality of the O-ring is determined. For example, the burr 24 to O-ring, if there is no chipping 25 and surface scratches 26, in the window W _1, W _2, W number of black pixels on ₅ 0, and the window W _3, W number of white pixels on the ₄ 0 Becomes

Thus, all the windows W ₁ , W
_{2, W 3, W 4,} W 5 number of white and black pixels on the, if not exceed the acceptance criteria value, determining the O-ring is determined to be non-defective, conversely, if exceeded defective Then, each signal of good or bad is sent to the controller 16 shown in FIG. 4, and an operation command signal is sent from the controller 16 to the defective product discharge nozzle 7a. The good product is blown off and sent into the container 7.

In the embodiments of FIGS. 1, 2 and 4 described above,
The first inspection means 1 includes a CCD camera 10, a coaxial incident illumination lamp 11, a sensor not shown, an image processing means 17, a controller 16,
It comprises an operation unit 22, a monitor 23, and the like. Second
The inspection means 2 has the same configuration.

Further, as shown in FIG. 4, the X-direction outside measuring device 31 of the seal S is connected to the controller X, and the Y-direction outside measuring device 31 is provided.
The reference numeral 32 is connected to the controller Y, and further to the calculation means 33. Since the seal S is placed and sent on the transparent plate 4, a laser measuring device that irradiates a laser beam from below and receives the laser beam from above is preferably used as each of the external meters 31 and 32. The arithmetic means 33 averages the outer diameters in the orthogonal X and Y directions to reduce measurement errors due to elastic deformation. (Note that it is desirable to measure the inner diameter as well as the outer diameter. Alternatively, the outer or inner diameter and the width can also be measured.)

If the average value in the X direction and the Y direction is out of the predetermined range, the controller 16 outputs the discharge nozzle
A signal to activate 34a is output, and
Blow off to 34 and discharge.

Since the width of the light-colored ring due to the reflection of the seal S other than the O-ring differs depending on the radial position (cross-sectional shape), the above-mentioned windows W ₁ , W ₂ , W ₃ , The dimensions and positions of W ₄ and W ₅ may be set (input) in advance in accordance with the type (cross-sectional shape) of the seal.

In the above, the binarized image processing has been described. However, gray image processing, in which this is multi-valued and processed as a number of lightness differences of, for example, 256 levels, is also used.
preferable.

According to the inspection apparatus and the inspection method as described above, one seal S such as an O-ring may be used, for example, in a range of 0.
Inspection can be performed automatically at high speed within 5 sec. In particular, since the seal S placed on the transparent plate 4 is inspected from both upper and lower sides without reversing, the seal S can be inspected on both sides. The required inspection time per piece is almost the same as in the case of one side of the O-ring, and the two-sided inspection can be performed efficiently. In addition, the conventional problem that the seal cannot be smoothly fed at the reversal portion is also solved. Further, as is clear from the plan views of FIGS. 1 and 4, there is an advantage that the entire apparatus is downsized and the installation place is small.

The present invention can be freely changed in design other than the above-described embodiment. For example, the inspection order of burrs, chips, and surface flaws in the flowchart shown in FIG. The changes are free. In addition to the turntable, a plate that performs linear reciprocating feed or an endless conveyor made of a transparent material may be used as the transparent plate 4. Instead of the defective product discharge nozzles 7a and 34a, a system in which the seal is bounced off by a mechanical contact member may be employed. In addition, (in FIG. 11, the positions of the optical axes 38 and 39 are slightly different by a small dimension ΔX, but the positions are further shifted.) The first inspection means 1 and the second inspection means 2 are two-dimensionally arranged. It is also preferable to dispose them at different positions on the upstream and downstream sides as seen in FIG.

[0037]

According to the present invention, the following significant effects can be obtained by the above-described structure.

According to the first aspect, the defect of the seal S can be automatically and efficiently inspected on both front and back surfaces. In addition, even in the case of a small-diameter and thin seal S, troubles such as stagnation and clogging of the feed (such as the stagnant or clogged feed in the conventional reversing method) can be performed smoothly. In addition, an efficient inspection can be reliably realized. Of course, since the surface flaw of the seal S is inspected on both sides, the reliability of the inspection is improved. (Since the conventional reversing means can be omitted), the structure of the device can be simplified and made compact. According to the second aspect, the dimensional inspection based on the XY average is performed unattended, and a high-speed and high-accuracy inspection (with a small measurement error) can be realized. For example, at a high speed of 120 pieces / min.
It is possible to inspect the size of the seal S such as a ring. According to the third aspect, the entire inspection apparatus can be made compact. Inspection from both upper and lower directions
Easy to do.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a front view thereof.

FIG. 3 is a schematic perspective view.

FIG. 4 is an explanatory diagram of the entire configuration.

FIG. 5 is an explanatory diagram of coaxial epi-illumination and imaging.

FIG. 6 is a flowchart.

FIG. 7 is an explanatory diagram of an inspection method.

FIG. 8 is an explanatory diagram of an image processing method.

FIG. 9 is an explanatory diagram of an inspection method using image processing.

FIG. 10 is an explanatory diagram of a window W.

FIG. 11 is an explanatory diagram of main parts when the optical axis of the CCD camera is slightly shifted.

[Explanation of symbols]

 S seal L axis 1 First inspection means 2 Second inspection means 4 Transparent plate 17 Image processing means 21 Light-colored ring-shaped part 31 X-direction outside measurement 32 Y-direction outside measurement

Claims (3)

[Claims] 1. A transparent plate on which an annular seal is placed and fed,
First inspection means for performing image processing on an image of a light-colored ring-shaped portion reflected on the sealing surface by applying illumination from the front side of the transparent plate to perform an appearance inspection for surface scratches and the like; Image processing of the image of the light-colored ring-shaped portion reflected from the back surface of the seal by illuminating the surface to inspect the appearance such as surface scratches
A seal inspection device, comprising: an inspection unit. 2. The method of measuring outer diameters along X-axis and Y-axis of orthogonal coordinates having an origin at a center point of an annular seal.
Out-of-direction measurement / Y-direction outside measurement, and calculating means for calculating an average value of the X-direction outside diameter and the Y-direction outside diameter measured by the X-direction outside measurement and the Y-direction outside measurement, The seal inspection device according to claim 1, further comprising: 3. The seal inspection apparatus according to claim 1, wherein the transparent plate is a turntable that is driven to rotate about a vertical axis.