JPS637324B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seal end face boundary inspection device for a circular seal member, and more particularly to an improved seal end face boundary inspection device that can optically and automatically inspect the seal end face boundary in a non-contact manner. .

BACKGROUND OF THE INVENTION Circular seal members are used in various industrial fields for hermetic seals and many other purposes, and are made of various materials such as elastic materials such as rubber or plastics. This type of circular seal member has a seal end boundary that forms the seal part, and defects in this seal end boundary may pose a major problem. A method for testing was requested.

For example, as is well known, various seal members are used in hydraulic or hydraulic equipment, and in particular, ring-shaped or cup-shaped circular seal members are used for pistons that slide within cylinders. The components form the most important functional components for pressure transmission. Therefore, the end face boundary of the circular seal member must be machined with high precision.
The surface defects cause pressure leakage, reduced durability, and damage to the sealing member, so the quality must be thoroughly inspected before being incorporated into equipment.

As the aforementioned circular seal member, the rubber cup in the brake cylinder of automobiles is well known, and it forms an important functional part that converts the driver's brake pedal force into hydraulic pressure and applies braking force to the wheels. Good quality and high durability are required because deterioration in quality has a large negative impact on the braking function of automobiles. Therefore, all cups for automobiles, etc. must be inspected before they are assembled into brake cylinders to reliably detect even minute surface defects, and such cups must be removed as defective products.

Defects in conventional circular seal members are mainly detected by visual inspection, and in the case of the cups and the like described above, visual inspection is performed on all units, which has the disadvantage of requiring a large number of inspectors. Furthermore, visual inspection has the disadvantage that there are large variations in inspection accuracy due to individual differences or fatigue levels, and that it is not possible to automatically and effectively inspect a large number of seal members.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to optically and automatically inspect a circular seal member made of a soft material such as rubber without mechanically deforming it, without contacting it. An object of the present invention is to provide an improved seal end face boundary inspection method and apparatus that can reliably inspect even minute defects and eliminate them as defective products.

In order to achieve the above object, the present invention provides a rotating table on which a circular seal member used as a rubber cup in an automobile brake cylinder is placed and rotated, and an end face forming a ridge of a sealing surface of the circular seal member. A slit beam generating device is provided at the boundary, which irradiates the slit beam vertically with a slit beam that passes through the end face boundary and has a width sufficiently longer than the end face boundary in the rotation radius direction, and repeatedly scans from one end side to the other end side. A photoelectric detection array that receives transmitted light from the end face boundary and sequentially converts it into an electrical signal and outputs it, and a photoelectric detection array that inspects the end face boundary scan timing for each array scan based on the output of the photoelectric detection array and outputs a timing detection signal. a comparator, a counter that starts counting clock pulses in synchronization with the start of each array scan and outputs the count value when the timing detection signal is output as a boundary detection count value, and a boundary detection count value output from the counter. a defect detection circuit that processes continuously during at least one rotation of the rotary table, sequentially compares the boundary detection count value for each array scan, and detects a defect at the edge boundary portion based on a sudden change in the count value at the time of defect detection; , is characterized in that it is possible to optically inspect the end face boundary of the sealing surface without contact.

Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an automobile cup as a preferred example of a circular seal member used for inspection of surface defects in the present invention, and this circular seal member 10 is made of soft rubber and is It has an axially symmetrical shape and is inserted into an automobile brake cylinder so that its outer peripheral surface acts as a sealing surface. The sealing member 10 in FIG. 1 has four main sealing parts, namely, sealing surfaces 10a and 10b consisting of two truncated conical surfaces that contact the cylinder, and an end face boundary forming the ridge of both sealing surfaces 10a and 10b. Part 10c
In the present invention, the end surface boundary portion 10c, which includes the ring-shaped machined surface 10d on the upper surface of the seal member 10 and is in sliding contact with the cylinder and receives a large pressure, is inspected for surface defects.

2 and 3 show a preferred embodiment of the seal surface inspection device according to the present invention, in which the circular seal member 10 is placed on a rotary table 12, and the shaft 100 of the seal member 10 is placed on a rotary table 12. and the rotary table shaft 20 of the rotary table 12
0 are positioned approximately on the same axis. A bevel gear 16 is fixed to the rotary table shaft 14 of the rotary table 12, and by meshing and coupling the small bevel gear 20 fixed to the motor 18 and the bevel gear 16, the bevel gear 16 is rotated by the rotation of the motor 18. The stand 12, ie, the circular seal member 10, is rotated in the direction of arrow A. An encoder 22 is attached to the lower end of the rotary table shaft 14.
is fixed, the rotational position and angle of the sealing member 10 are electrically detected as a rotational angle signal, and this signal is supplied to the defect detection circuit 24.

A slit beam generating device 26 is provided near the sealing member 10, and the slit beam generating device 26 includes a light source 28 for generating a parallel beam consisting of a lamp or a laser, and this parallel beam is shown by hatching (the third (FIG.) A lens mirror system 30 that converts the beam into a slit beam and irradiates it to the outside is included, and the slit beam 300 passes through the end face boundary portion 10c of the circular sealing member 10 and is irradiated. A photoelectric detection array 32 is provided along the slit beam 300 on the optical path of the slit beam 300, which has a width sufficiently longer than the boundary of the seal end surface in the radial direction of rotation, that is, along the radial direction of the rotary table 12. and the end face boundary portion 1 of the circular seal member 10
The slit luminous flux transmitted through 0c can be photoelectrically converted. The photoelectric detection array 32 in the embodiment is composed of a diode array or the like arranged in a line, and together with the scanning circuit 34 to which the diode array is electrically connected, forms a self-scanning photoelectric detection array. A boundary detection circuit 36 is provided to detect the end face boundary portion 10c of transmitted light based on the output of the photoelectric detection array 32, and a boundary detection circuit 36 is provided to scan and drive the photoelectric detection array 32.
6 is provided with a clock oscillator 38, and its scanning clock 402 sequentially scans and drives the scanning circuit 34, so that the photoelectric detection array 32 is sequentially photoelectrically converted from the left side in FIG. Scanning circuit 34
To trigger the start of the scan, the output of the clock oscillator 38 is fed to a scan start signal generator 40, and a scan start signal 404 starts the scan of the scan circuit 34. The scan start signal 404 is also used as a reset signal for the counter 42 that counts the scan clock 402, and the counter 42 starts counting the scan clock 402 from zero when the photoelectric detection array 32 starts scanning. The photoelectric conversion signal of the photoelectric detection array 32 is supplied to a comparator 44 that inspects the end face boundary scan timing for each array scan based on this signal and outputs a timing detection signal. Therefore, when the scanned element of the photoelectric detection array 32 is irradiated with light, no output is generated from the comparator 44, but the scanned element of the photoelectric detection array 32 enters the shadow part of the end face boundary part 10c. When the light irradiation ceases, the comparator 44 supplies a timing detection signal representing the end face boundary scan timing, and the end face boundary can be detected.

That is, the output of the comparator 44 is supplied to the counting stop input of the counter 42, and during boundary scanning when the timing detection signal is output, the counter 42 stops counting the scan clock 402 and uses the count value at that time as the boundary detection count value. Output as .

Then, the boundary detection count value of the counter 42 is latched by a latch circuit 46, and the latch value of the latch circuit 46 is supplied to the defect detection circuit 24 as a detection signal of the boundary detection circuit 36 every time the photoelectric detection array 32 is scanned once. be done. Note that the output of the comparator 44 is supplied to the latch circuit 46 as a load signal and to the defect detection circuit 24 as an interrupt signal.

The defect detection circuit 24 consists of a microprocessor or the like, and continuously processes the detection signal from the boundary detection circuit 36, that is, the boundary detection count value during at least one revolution of the turntable 12, and sequentially processes the boundary detection count value for each array scan. By comparison, a change in the end face boundary when there is a defect in the outer seal portion 10c is detected based on the sudden change in the boundary detection count value, a defect signal is output, and the display unit 48 and the sorting mechanism 50 are controlled by this defect signal. drive The display unit 48 displays a defect when the defect in the outer seal portion 10c is equal to or greater than a reference value, and the sorting mechanism 50 functions to remove the circular seal member 10 having such a defect as a defective product.

The embodiment of the present invention has the above configuration, and its operation will be explained below.

When the circular seal member 10 to be inspected is supplied to the rotary table 12 from a supply device (not shown), the shaft 100 of the circular seal member 10 and the rotary table shaft 2 of the rotary table 12 are connected to each other.
00 is aligned almost coaxially with the rotary table 12.
is rotationally driven by the motor 18, and at the same time, a slit beam 300 is irradiated from the slit beam generating device 26 toward the end face boundary portion 10c of the circular sealing member 10 from below in the figure. This slit luminous flux 30
0 has a cross-sectional shape that is long in the substantially radial direction of the rotary table 12, and its longitudinal width is the same as that of the circular seal member 10.
Even if the diameter or other changes are made, the end face boundary 1
The size is set to cover 0c, and it becomes possible to inspect various types of circular seal members 10 with the same inspection device.

The end face boundary of the end face boundary portion 10c is accurately projected onto the photoelectric detection array 32 by the irradiation with the slit beam 300 described above. That is, in the area where the slit light beam 300 is not blocked by the end face boundary 10c, it reaches the photoelectric detection array 32 as it is, and its projection surface becomes "bright", while the shadow part blocked by the end face boundary 10c is not blocked by the projection surface. The surface becomes "dark" and the boundary between light and dark accurately indicates the end face boundary of the end face boundary part 10c. Therefore, in the optical inspection in the present invention, the end face boundary 1
The end face boundary portion 10c can be placed at any position within the slit beam 300 without the need for image formation on the slit beam 300, and no adjustment is required when changing the diameter of the sealing member 10 or other changes described above. This makes it possible to obtain an inspection device with extremely high practical value without any problems.

The boundary between brightness and darkness of the photoelectric detection array 32 is detected as a timing detection signal by the boundary detection circuit 36, and the boundary signal can be discriminated depending on which element of the photoelectric detection array 32 the boundary between brightness and darkness is located. This discrimination can be performed by a well-known method, for example, by assigning an address to each element of the photoelectric detection array 32 and making it possible to discriminate each address by the count value of the scanning clock 402. That is, in the self-scanning photoelectric detection array in this embodiment, each element is sequentially scanned in accordance with the scanning clock 402 using the scanning start signal 404, and the amount of light incident on each element is expressed as a time-series signal synchronized with the scanning clock 402. This photoelectric conversion signal becomes zero immediately after scanning the bright/dark boundary corresponding to the edge boundary portion 10c, and the scanning clock count value at this time becomes the counter 4.
6, and this count value is held in the latch circuit 46 as a boundary detection count value.
This held value corresponds to a specific address of the photoelectric detection element at the bright/dark boundary, and is output from the boundary detection circuit 36 to the defect detection circuit 24 as a boundary signal.

In the present invention, the rotational speed of the rotating table 12 is set to a speed sufficiently slow compared to one scanning period of the photoelectric detection array 32, and as a result, the end face boundary portion 10
The end face boundary of c is to be thoroughly inspected.

The defect detection circuit 24 compares the boundary detection signals during one revolution of the rotary table 12 and can detect a surface defect based on a significant change in signal value at the boundary when there is a surface defect, and this defect detection is performed using a circle. In order to eliminate periodic fluctuations due to misalignment between the mold sealing member 10 and the rotary table 12, etc., the photoelectric detection array 32 is compared every scan, and the defect detection function is performed by a sudden change in signal value when detecting a defect. Can be done. Then, the output of the defect detection circuit 24 operates the display section 48 and the sorting mechanism 50, so that it is possible to display the quality of the product and to remove defective products.

As explained above, according to the present invention, by transmitting and irradiating the slit light beam onto the boundary of the seal end face, it is possible to perform an extremely highly accurate and stable inspection operation, automate the inspection, and process a large number of circles to be inspected. It is possible to quickly inspect molded parts, and it is possible to provide an inspection device that is particularly effective for automobile brake cups, etc., and it also makes it possible to provide an inspection device that is particularly effective for automobile brake cups, etc., and is also capable of applying any mechanical stress to circular parts made of soft materials such as rubber. It has the advantage that accurate inspection can be performed without contact.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a preferred example of a circular seal member to be inspected according to the present invention, FIG. FIG. 3 is a schematic explanatory diagram including the circuit configuration of FIG. 2. 10...Circular seal member, 10c...End face boundary part,
12... Turntable, 24... Defect detection circuit, 26... Slit light beam generator, 32... Photoelectric detection array, 36
...Boundary detection circuit, 300...Slit light flux.

Claims (1)

[Scope of Claims] 1. A rotary table on which a circular seal member used as a rubber cup in an automobile brake cylinder is placed and rotated; A slit beam generator that transmits through the boundary and vertically irradiates a slit beam having a width sufficiently longer than the end face boundary in the rotation radius direction; a photoelectric detection array that receives transmitted light and sequentially converts it into an electrical signal and outputs it; a comparator that inspects the end face boundary scan timing for each array scan based on the output of the photoelectric detection array and outputs a timing detection signal; A counter that starts counting clock pulses in synchronization with the start of scanning for each array scan and outputs the count value when the timing detection signal is output as the boundary detection count value, and a counter that outputs the count value when the timing detection signal is output as the boundary detection count value, and a defect detection circuit that processes continuously during one rotation, sequentially compares the boundary detection count values for each array scan, and detects a defect at the edge boundary by a sudden change in the count value when detecting a defect; A seal end face boundary inspection device for a circular seal member, which is capable of optically inspecting the boundary in a non-contact manner.