JP6235816B2 - Defect inspection equipment for molded products - Google Patents

Description

  The present invention relates to an apparatus for inspecting whether there is a defect in a cylindrical molded article made of a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity) such as a dust cover and having at least one end opened. .

  2. Description of the Related Art Conventionally, as an apparatus for inspecting the presence or absence of defects in a molded product made of a rubber-like elastic material, for example, those disclosed in the following patent documents are widely known.

  As shown in FIG. 5, this type of defect inspection apparatus includes an inspection table 101 on which an inspection object W that is a molded product formed into a cylindrical shape with a rubber-like elastic material such as a dust cover, and the inspection table 101. , A drive device 102 that rotates at a low speed, a light source 103 that irradiates illumination light toward the inspection object W on the inspection table 101, and a CCD camera that receives and captures reflected light from the surface of the inspection object W. And an arithmetic processing unit 105 that performs various control processes for determining a defect by image processing of image data from the imaging apparatus 104 and driving control of the driving apparatus 102.

  That is, in the conventional defect inspection apparatus having the above configuration, an image of the surface of the inspection object W is picked up by the image pickup device 104, and the image data is input to the arithmetic processing device 105. In the arithmetic processing device 105, the image data A defect present on the surface of the inspection object W is detected from a difference in luminance value of each pixel. In this type of defect inspection apparatus, this is detected by mechanically pressing and deforming the object W to be inspected using a pressing jig (not shown) to expand a defective portion made up of small scratches or cracks. It is also known to facilitate this (see, for example, Patent Document 1 below).

Japanese Utility Model Publication No. 4-8952

  However, since the object to be inspected W is deformed only by the part in contact with the jig, the object to be inspected W is deformed by the pressing jig. In addition, a problem that it is necessary to prepare different jigs according to the shape of the inspection object W is pointed out.

  The present invention has been made in view of the above points, and the technical problem thereof is an apparatus for inspecting a defect of a cylindrical molded article made of a rubber-like elastic material and having at least one end opened. It is to improve the reliability of defect inspection.

請 Motomeko moldings defect inspection apparatus according to one aspect of the present invention, at least one end is molded of rubber-like elastic material is an apparatus for inspecting defects of the opened tubular object to be inspected, the inspection object An inspection table to be fitted, an air supply means for expanding the inspection object by supplying air to the inner peripheral space of the inspection object so that the inner peripheral space has a predetermined pressure value, and the inspection object An image pickup means for picking up the surface of the image, and the luminance value of each pixel constituting the image data from the image pickup means is compared with a preset threshold value, and the defective portion is based on the area of the pixel whose luminance value exceeds a predetermined threshold value. It is characterized by comprising a judging means for judging the presence or absence of the.

  According to the above configuration, when a defective part due to scratches or cracks is present on the surface of the inspection object, even if the defective part is closed before the inspection object is expanded, the supply from the air supply means is performed. By expanding the object to be inspected by air, the defect portion is expanded so as to open, so that it can be reliably extracted from the image data obtained by the imaging means.

A defect inspection apparatus for a molded product according to a second aspect of the present invention is the structure according to the first aspect, further comprising pressure measuring means for detecting the pressure in the inner peripheral space of the inspection object, wherein the determination means includes the determination means, It is characterized in that it is determined whether the defective portion is penetrating or not penetrating based on the measured value by the pressure measuring means.

  According to the above configuration, when the defective part of the inspection object is caused by non-penetrating scratches or cracks, the pressure in the inner peripheral space of the inspection object is within a predetermined time due to supply from the air supply means. When the set value is reached, but the defective part of the object to be inspected is due to a scratch or crack that has penetrated, the gas pressurized and supplied from the air supply means leaks from the defect part that has penetrated. Since the pressure in the space does not reach the set value within a predetermined time, it is possible to determine whether or not the defective portion has penetrated.

Further, the molded product defect inspection apparatus according to the invention of claim 3, in the structure according to claim 1 or 2, supply air to the inner peripheral space of the object to be inspected, fits the object to be inspected the It is performed through a pressurized gas supply path provided on the inspection table.

  According to the above configuration, when the inspection object is fitted to the inspection table, the inspection object is supplied by supplying air to the inner peripheral space of the inspection object through the pressurized gas supply path formed in the inspection table. Since it is inflated, the fitting operation and the removing operation can be easily performed.

  According to the defect inspection apparatus for molded articles according to the present invention, the object to be inspected is inflated and deformed uniformly around the entire periphery by supplying air to the inner peripheral space of the object to be inspected. It is possible to detect defective parts due to closed cracks, etc., and it is not necessary to prepare different jigs according to the shape of the object to be inspected, and it is possible to determine whether the defective part has penetrated or not penetrated. Can be improved.

It is a schematic structure explanatory view showing a preferred embodiment of a molded product defect inspection apparatus according to the present invention. It is explanatory drawing which shows the example of the image imaged without expanding the to-be-inspected object. It is explanatory drawing which shows the example of the image imaged in the state which expanded the same to-be-inspected object by FIG. 2 with supply air. It is schematic structure explanatory drawing which shows other preferable embodiment of the defect inspection apparatus of the molded article which concerns on this invention. It is schematic structure explanatory drawing which shows an example of the defect inspection apparatus of the molded article by a prior art.

  Hereinafter, a preferred embodiment of a defect inspection apparatus for a molded product according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of a defect inspection apparatus according to an embodiment of the present invention. That is, the defect inspection apparatus includes an inspection table 1 to which an inspection object W, which is a molded product formed of a rubber-like elastic material, is attached, a driving device 2 that drives the inspection table 1, and an inspection table 1. A light source 3 such as an LED that irradiates illumination light toward the inspection object W, an imaging device 4 that receives reflected light from the surface of the inspection object W and picks up an image, and an inspection attached to the inspection table 1 The air pump 5 that expands the inspection object W by supplying air to the inner peripheral space S of the object W, the pressure gauge 6 that measures the pressure in the inner peripheral space S of the inspection object W, the imaging device 4 and the pressure gauge 6 includes an arithmetic processing unit 7 that determines a defect based on data from the unit 6.

  In the illustrated example, the object W to be inspected is specifically a dust cover, which is formed of a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity), such as a ball joint or the like. A large-diameter mounting portion W1 that can be closely fitted to the outer peripheral surface of the housing (not shown), a small-diameter mounting portion W2 that can be closely fitted to the outer peripheral surface of the shaft portion (not shown) of the ball joint or the like, and the large diameter A cylindrical flexible film portion W3 that connects between the attachment portion W1 and the small-diameter attachment portion W2 is provided.

  An inspection table (also referred to as Yatoi) 1 includes a turntable 11 that is horizontally swiveled at a low speed by a drive device 2, a shaft 12 that is erected on the turntable 11 concentrically with the center of rotation, and a large lower portion of the shaft 12. A lower mounting jig 13 which is extrapolated to the diameter portion 12a and fixed to an appropriate height by the set screw 14, and a lower screw 12 which is not shown in the upper small diameter portion 12b of the shaft 12 from the lower mounting jig 13 It has the upper attachment jig | tool 15 fixed to upper suitable height.

  The inspection table 1 has the inspection object W (dust cover) attached to the shaft 12 with the large diameter attachment portion W1 attached to the lower attachment jig 13 in close contact with the small diameter attachment portion W2 at the upper portion. It can be attached to the mounting jig 15 in a close state.

One end of the shaft 12 in the inspection table 1 is connected to an air supply pipe 51 extending from the air pump 5, and the other end is an inner circumference of the inspection object W attached to the lower mounting jig 13 and the upper mounting jig 15. An air supply path 16 that opens to the space S is provided. Therefore, air can be pressurized and supplied to the inner circumferential space S of the inspection object W by the air pump 5. The air supply path 16 corresponds to a pressurized gas supply path.

  Further, the lower mounting jig 13 in the inspection table 1 is connected to an annular groove 13a along a close position with the large-diameter mounting portion W1 of the inspection object W and a vacuum pump (not shown) extending from the annular groove 13a. An intake passage 13b is provided, and the upper mounting jig 15 is also connected to the vacuum pump extending from the annular groove 15a along the close position with the small-diameter mounting portion W2 of the inspection object W and the annular groove 15a. An intake passage 15b is provided. That is, by introducing a negative pressure into the annular grooves 13a and 15a through the intake passages 13b and 15b by the suction action of the vacuum pump, the large-diameter mounting portion W1 and the small-diameter mounting portion W of the inspection object W are placed on the inspection table 1. The upper surface of the lower mounting jig 13 and the lower surface of the upper mounting jig 15 can be firmly attached to each other.

The imaging device 4 is a IMAGING means, an objective lens facing the outer peripheral surface of the object W, the image of the CCD or CMOS or the like for photoelectrically converting the electric charge corresponding to the brightness of the light focused by the objective lens And an electric signal from the image sensor is output as image data.

Air pump 5 is a air supply means, as the inner circumferential space S of the object W mounted on the inspection table 1 becomes a predetermined pressure, into the space S through the supply pipe 51 and the air supply passage 16 Air is supplied under pressure.

Pressure gauge 6 is a pressure measuring means, the pressure in the inner circumferential space S of the object W to be pressed is measured by the air supplied from the air pump 5, and outputs the measurement data.

Processor 7 is a determine constant means, for example, a general-purpose personal computer, and includes input devices such as a monitor display, a keyboard, a mouse, and a storage device. The arithmetic processing unit 7 performs necessary arithmetic processing on the image data captured from the imaging device 4 and the measurement data from the pressure gauge 6 according to a predetermined processing program, and performs defect determination based on a set threshold value or the like. Is.

  In defect inspection of an inspection object W such as a dust cover using the defect inspection apparatus having the above-described configuration, first, the inspection object W is extrapolated to the shaft 12 in the inspection table 1, and a large-diameter mounting portion of the inspection object W is provided. W1 is closely fitted to the lower mounting jig 13, and the small-diameter mounting part W2 is closely fitted to the upper mounting jig 15. The annular grooves 13a and 15a along the fitting part are negatively fitted by a vacuum pump (not shown). By introducing the pressure, the large-diameter mounting portion W1 and the small-diameter mounting portion W2 of the inspection object W are firmly attached to the lower mounting jig 13 and the upper mounting jig 15 of the inspection table 1.

  Further, in the process of attaching the inspection object W, the inspection object W is expanded by pressurizing and supplying air to the inner circumferential space S of the inspection object W by the air pump 5, so that the oils and fats for lubrication are lubricated. Therefore, the extrapolation work to the shaft 12 can be easily performed without using the above, and the attachment work of the inspection object W to the inspection table 1 can be easily performed.

  Then, by introducing negative pressure into the annular grooves 13a and 15a of the lower mounting jig 13 and the upper mounting jig 15 of the inspection table 1, the large-diameter mounting part W1 and the small-diameter mounting part W2 of the object W are inspected. In the state where the lower mounting jig 13 and the upper mounting jig 15 are in close contact with each other, the inner circumferential space S is a sealed space, so that the internal pressure of the inner circumferential space S increases due to the pressurized supply of air. Thus, the inspection object W is expanded and deformed. That is, the dust cover as the inspection object W has an appearance as shown in FIG. 2 in a state before the expansion deformation, for example, while a predetermined pressure value (for example, 0.06 MPa) is applied to the inner circumferential space S of the inspection object W. When the air is pressurized and supplied so as to achieve a positive pressure of a certain degree, a swelled shape is obtained as shown in FIG.

  The surface of the inspection object W is irradiated with illumination light by turning on the light source 3, and the turntable 11 is horizontally rotated at a low speed by the driving device 2, while the surface of the inspection object W that is slowly rotated is 1 During the rotation, the imaging device 4 captures a plurality of times at a predetermined time interval, thereby capturing the entire circumference and outputting the image data.

  The image data output from the imaging device 4 is taken into the arithmetic processing unit 7, and the arithmetic processing unit 7 compares the luminance value of each pixel constituting the image data with a preset threshold value, and the luminance value is a predetermined threshold value. The number of pixels exceeding 1 is extracted, and it is determined by the number of pixels (area) whether it is a defective portion or a minute processing trace that is not a defect.

  In the state before the expansion deformation, as shown in FIG. 2, the relatively large defect A1 is obvious, whereas the defect portions A2 and A3 are in a state in which the portions such as scratches and cracks are closed. Although not revealed in the data, in the defect inspection apparatus of the present invention, the defect portions A2 and A3 are expanded to open by expanding the inspection object W as shown in FIG. The closed defect that could not be detected is also manifested in the image data by the imaging means 4 and can be detected.

  On the other hand, the pressure in the inner circumferential space S of the inspection object W is measured by the pressure gauge 6, and the measurement data is taken into the arithmetic processing device 7. If the defect portion A is shallow and does not penetrate the inspection object W in the thickness direction, the pressure in the inner circumferential space S reaches a predetermined pressure value within a preset time, and is caused by the air pump 5. Even after the pressure supply of air is stopped, the pressure in the inner circumferential space S is maintained. However, if the defective portion A penetrates the workpiece W in the thickness direction, the supplied air penetrates. The defect leaks to the outside, and the pressure in the inner circumferential space S of the inspection object W does not reach a predetermined pressure value within a preset time (the inspection object W does not expand to a predetermined size). Or even if it raises to a predetermined pressure value, if the pressurization supply of the air by the air pump 5 will be stopped, the pressure of the inner peripheral space S will fall over time.

  Therefore, it is determined from the measurement data obtained by the pressure gauge 6 whether the defective portion A is non-penetrating or penetrating, and the defective portion detected by, for example, image data from the imaging device 4 is smaller than the set value. Even if it is determined that the defect is a penetrating defect or a non-penetrating defect, the size of the defect portion detected by the image data from the imaging device 4 exceeds the set value. (Defects that may penetrate due to crack growth) are judged as NG, and defective parts detected by image data are smaller than a set value and judged as non-penetrating, etc. A logic circuit can be configured.

  According to the present invention, it is possible to detect a defect that could not be detected by inspection only by image data from the imaging device 4 or by inspection only by leak detection by the pressure gauge 6 regardless of image data.

  Note that the object to be inspected is also removed by the air pump 5 when the object W is removed from the inspection table 1 by releasing the negative pressure in the annular grooves 13a and 15b of the lower mounting tool 13 and the upper mounting tool 15 of the inspection table 1. By pressurizing and supplying air to the inner circumferential space S of W, work can be easily performed as in the case of attachment.

  Next, FIG. 4 shows a schematic configuration of a defect inspection apparatus according to another embodiment of the present invention. In this defect inspection apparatus, the difference from the embodiment shown in FIG. 1 is that the inspection table 1 does not include the shaft 12, and the air pump 5 supplies pressurized air to the inner circumferential space S of the inspection object W. In other words, the air supply path 16 is provided in the lower mounting jig 13 (or the upper mounting jig 15).

  Specifically, the lower mounting jig 13 in the inspection table 1 is formed with a columnar convex portion 13c that can be fitted over the upper neck portion of the large-diameter mounting portion W1 of the object W to be inspected. Similarly, a columnar convex portion 15c is formed in which the lower neck portion of the small-diameter mounting portion W2 of the inspection object W can be fitted, and in this fitted state, by a suction action of a vacuum pump (not shown). By introducing negative pressure into the annular grooves 13a and 15a via the intake passages 13b and 15b, the large-diameter mounting portion W1 and the small-diameter mounting portion W of the inspection object W are placed on the upper surface of the lower mounting jig 13 in the inspection table 1. In addition, the upper mounting jig 15 can be firmly attached to the lower surface. Other configurations can be basically the same as those in FIG.

1 Inspection table 16 Air supply path (Pressurized gas supply path)
3 Light source 4 Imaging device 5 Air pump (air supply means)
6 Pressure gauge (pressure measuring means)
7. Arithmetic processing device (determination means)
S Inner space W Inspected object

Claims (3)

An apparatus for inspecting a defect of a cylindrical inspection object formed of a rubber-like elastic material and having at least one end opened,
An inspection table for fitting the inspection object;
An air supply means for inflating the test object by supplying air to the inner peripheral space of the test object so that the inner peripheral space has a predetermined pressure value ;
Imaging means for imaging the surface of the inspection object;
A determination unit that compares the luminance value of each pixel constituting the image data from the imaging unit with a preset threshold value and determines the presence or absence of a defective portion based on the area of the pixel whose luminance value exceeds a predetermined threshold value ;
A defect inspection apparatus for a molded product, comprising: A pressure measuring means for detecting the pressure in the inner space of the object to be inspected;
2. The defect inspection apparatus for a molded product according to claim 1, wherein the determination unit determines whether the defective portion is penetrating or not penetrating based on a measurement value obtained by the pressure measuring unit. Air supply to the inner peripheral space of the object to be inspected, wherein said in claim 1 or 2, characterized in that takes place via a pressurized gas supply passage provided in the inspection station for fitting the object to be inspected Defect inspection equipment for molded products.

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