JPH11121143A - Spark plug inspection method and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct inspection accurately and efficiently by retrieving conforming parts of a pickup image to a master image so as to distinguishing as the part of a chip, superimposing the conforming parts so as to positioning the pickup image or the master image, and producing and outputting inspection information on the dimension or the position of the tip based on the same. SOLUTION: The master images 50 of respective corner portions are prepared in a square pickup image 51, and the one required for determining the contour line of a constituting portion is used for dimension measurement. The master image 50 and the pickup image 51 are formed by the combination of the output states of picture elements capable of intermediate density outputs as a gray scale. The master image 50 is parallel moved between the picture elements of the pickup image 51 so as to retrieve conforming positions, to compute the density difference between the corresponding elements, and to compute a sum or an average mean so that the pickup image part having the minimum sum value computed at respective positions is selected as the confirming part. Thereby, the inspection of a position or a decentering amount is efficiently conducted, the contour line position is specified even without clear contrast so as to enhance inspection accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for inspecting a spark plug.

[0002]

2. Description of the Related Art In recent years, spark plugs used in internal combustion engines have been used in which a noble metal tip is fixed to at least one of a ground electrode and a center electrode in order to improve spark wear resistance. In this case, the positioning accuracy of the noble metal tip is important in order to ensure sufficient spark wear resistance. For example, the center axis of the chip fixed to the ground electrode side and the center axis of the center electrode or the chip fixed to the center electrode may be eccentric due to a shift in the chip fixing position. If such a displacement occurs, for example, the life is shortened due to uneven consumption of the chip,
It leads to troubles such as ignition mistake.

[0003]

Conventionally, for example, eccentricity inspection of a spark gap and dimensional inspection of each part forming the periphery of the gap are often performed by visual inspection. In this case, the inspection accuracy varies due to individual differences. There is a problem that rejected products are likely to flow out due to omission of inspection. Therefore, in order to automatically perform an eccentricity inspection, a technique of capturing an image of a spark plug firing portion with a CCD camera and detecting the amount of eccentricity based on the image is disclosed in, for example, JP-A-8-153566. I have.

In the case of eccentricity detection using an image, it is necessary to accurately specify the position of a chip fixed to a ground electrode or a center electrode in order to improve the detection accuracy. However, the above publication does not disclose any specific inspection method when the above-mentioned chip is fixed to the ground electrode or the center electrode.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a spark plug in which a tip such as a noble metal tip is fixed to a ground electrode or a center electrode and which can accurately and efficiently inspect the tip position and gap eccentricity. An inspection method and apparatus are provided.

[0006]

The first aspect of the spark plug inspection method according to the present invention is a center electrode, a ground electrode disposed so that the tip side faces the center electrode, and a ground electrode. The present invention relates to a method for inspecting a spark plug including a tip fixed to at least one of a ground electrode and a spark gap to form a spark gap, and includes the following steps for solving the above-mentioned problem. . Photographing step: The spark plug is photographed so that an image of at least the chip and a portion of the center electrode or the ground electrode to which the chip is fixed (hereinafter referred to as a chip-fixed portion) is obtained. Chip discriminating step: In the photographed image, a master image having a shape corresponding to all or a part of the chip is prepared in advance, and a part that matches the master image in the photographed image is searched, so that the conforming part is at least one of the chips The part is determined as a part. Inspection information generating step: Based on at least one of the photographed image of the determined chip and the master image positioned so as to be superimposed on the matching part, the inspection information on at least one of the dimension and the position of the chip is generated. . Inspection information output step: The generated inspection information is output.

[0007] A first aspect of the spark plug inspection apparatus of the present invention corresponding to this is a center electrode, a ground electrode disposed so that the tip side faces the center electrode, and a connection between the center electrode and the ground electrode. The present invention relates to an apparatus for inspecting a spark plug including a chip fixed to at least one of them and forming a spark gap, and includes the following means in order to solve the above-mentioned problem. Photographing means: The spark plug is photographed so that an image of at least the chip and a portion of the center electrode or the ground electrode to which the chip is fixed (hereinafter referred to as a chip-fixed portion) can be obtained. Master image data storage means: Stores image data of a master image having a shape corresponding to all or a part of a chip in the captured image. Chip determining means: By searching for a portion that matches the master image in the captured image, the matching portion is determined as a portion that forms at least a part of the chip. Inspection information generating means: generates inspection information relating to at least one of the size and the position of the chip based on at least one of the photographed image of the determined chip and the master image positioned so as to be superimposed on the matching portion. I do. Inspection information output means: Outputs the inspection information.

According to the first method or apparatus of the present invention, by searching for a portion that matches a master image in a captured image, the matching portion is determined as a portion forming at least a part of a chip. . As a result, the chip portion can be accurately specified, and the inspection relating to the chip position, the gap eccentricity, and the like can be performed accurately and efficiently. In addition, even when a clear contrast does not occur between the chip and the electrode portion, the outline position of the chip portion can be accurately specified by using the master image, and the inspection accuracy can be improved.

Next, a second aspect of the method for inspecting a spark plug according to the present invention is that a center electrode, a ground electrode arranged so that the tip side faces the center electrode, and at least one of the center electrode and the ground electrode is provided. The present invention relates to a method for inspecting a spark plug including a chip that is fixed and forms a spark gap, and includes the following steps in order to solve the above-described problem. Photographing process: photographing the ground electrode-side chip fixed to the ground electrode and the center electrode, photographing the center electrode-side chip fixed to the center electrode and the ground electrode, the ground electrode side chip fixed to the ground electrode and the center electrode At least one of photographing of the center electrode-side chip fixed to the substrate and photographing of the center electrode and the center electrode-side chip fixed thereto is performed. Chip discriminating step: In the photographed image,
An image of a portion of the center electrode or the ground electrode to which the chip is fixed (hereinafter, referred to as a chip fixing portion) is determined. Inspection information generation step: information on the amount of eccentricity between the ground electrode-side chip and the center electrode, information on the amount of eccentricity between the ground electrode and the center electrode-side chip, based on the image information after the discrimination, the ground electrode-side chip At least one of the information on the amount of eccentricity between the center electrode side tip and the center electrode and the information on the amount of eccentricity between the center electrode side tip and the center electrode is generated as inspection information. Inspection information output step: The inspection information is output.

A second aspect of the spark plug inspection apparatus according to the present invention is a center electrode, a ground electrode arranged so that the tip side faces the center electrode, and a connection between the center electrode and the ground electrode. The present invention relates to an apparatus for inspecting a spark plug including a chip fixed to at least one of them and forming a spark gap, and includes the following means in order to solve the above-mentioned problem. Photographing means: photograph the ground electrode or the ground electrode-side chip fixed to the ground electrode, and the center electrode or the center electrode-side chip fixed to the center electrode. Chip discriminating means: in the photographed image,
An image of a portion of the center electrode or the ground electrode to which the chip is fixed (hereinafter, referred to as a chip fixing portion) is determined. Inspection information generating means: Based on the image information after the discrimination, generates information relating to the amount of eccentricity between the ground electrode or the ground electrode side tip and the center electrode or the center electrode side tip as the test information. Inspection information output means: Outputs the inspection information.

In the second method or apparatus according to the present invention,
In a captured image of the ground electrode or the ground electrode-side chip fixed to the ground electrode, and the center electrode or the center electrode-side chip fixed to the center electrode, the chip and the chip of the center electrode or the ground electrode are fixed. An image of a portion to be fixed (tip-fixed portion) is determined, and information on the amount of eccentricity between the ground electrode or the ground electrode side tip and the center electrode or the center electrode side tip is determined based on the image information after the determination. Generated as inspection information. Thus, even when a tip such as a noble metal tip is fixed to at least one of the ground electrode and the center electrode, the eccentric state of the spark gap formed by the tip can be inspected accurately and efficiently.

In the second method and apparatus of the present invention as well, a master image having a shape corresponding to all or a part of a chip is prepared in advance, and a portion matching the master image in a captured image is searched for. A compatible portion of the captured image with the master image is determined as a chip image portion forming at least a part of a chip, and at least one of the determined chip image portion and a master image positioned in a form superimposed on the chip image portion. Inspection information on at least one of the size and the position of the chip can be generated based on the above. As a result, the chip portion can be specified more accurately, and as a result, the inspection relating to the chip position, the gap eccentricity, and the like can be performed more accurately.

At the time of chip determination, a photographed image and a master image are formed by a combination of output states of a plurality of pixels capable of outputting an intermediate density. The part where the sum of the density differences is minimum can be selected as the compatible part. By doing so, the matching accuracy between the captured image and the master image is enhanced, and the chip shape can be specified more accurately, and the inspection accuracy is further improved. In this case, in the above method or apparatus, the density value level of each pixel changes from one of a state larger than the predetermined threshold and a state smaller than the threshold to the other in a direction intersecting with the chip outline direction. position,
Alternatively, a chip outline information generation step or means for determining a position where the rate of change of the density value level of each pixel detected along the direction intersecting with the chip outline direction as the chip outline position is determined. Can be. This allows
The position of the outer shape of the chip can be specified with high accuracy.

The chip outline direction can be determined, for example, by setting the outline of the master image as a temporary outline and the direction of the temporary outline.

In the case where the axial cross section of the chip is circular, in the chip discriminating step, the circular master image is adapted to the photographed image of the axial end face of the chip, and the chip outline information is obtained. In the generation step, three different points as the outlines of the axial end face of the chip are determined, and a circle passing through the three points can be determined as the outline of the axial end face. Thereby, the outline of the axial end face of the circular chip can be easily determined.
The circle can be specified by determining its center position and radius.

In this case, a plurality of sets of three points different from each other are determined, a center position and a radius of a plurality of circles passing through each of the three points are determined, and a final outline of the axial end face of the chip is defined by the plurality of points. If the average radius and the average radius of the circle are determined as circles having the center and the radius, respectively, the outline of the axial end face of the chip can be determined with higher accuracy. For example, when the tip is attached to the ground electrode or the center electrode by welding, even if the outer shape of the tip is somewhat unclear due to the formation of a welding droop around the tip, this is accurately determined by the above method. be able to.

The position of the chip may be specified, for example, in the form of an absolute position on the pixel plane. For example, if inspection of the gap eccentricity state or the mounting position of the chip is to be performed, the position of the chip must be determined. It is more desirable to appropriately select a predetermined component (position reference component) of the spark plug that gives the above, and obtain information giving a relative positional relationship between the position reference component and the chip as inspection information. In this case, the above-described method or apparatus includes a photographing step or means for photographing an image of the position reference component together with the chip, and a position reference configuration of the chip based on the photographed image of the chip and the photographed image of the position reference component. A chip position information generating step or chip position information generating means for generating positional relationship information for a portion is included.

A master image having a shape corresponding to all or a part of the position reference component is prepared in advance, and a portion matching the master image of the photographed image is defined as a position reference constituting at least a part of the position reference component. The position reference component part is determined based on at least one of the determined position reference component part image part and the master image positioned so as to be superimposed on the determined position reference component part image part. Can be specified. In this case, the captured image and the master image are formed by a combination of the output states of a plurality of pixels capable of outputting an intermediate density, and in the captured image, the total density difference between the corresponding pixels with the master image is calculated. Can be selected as the compatible part. Further, a position or a position where the density value level of each pixel changes from one of a state larger than the threshold and a state smaller than the threshold to the other with a predetermined threshold interposed therebetween in a direction intersecting with the outline direction of the position reference component. The position where the rate of change of the density value level of each pixel detected along the direction intersecting with the direction of the outline of the reference component is the maximum can be determined as the position of the outline of the position reference component. Thus, the position of the outline of the position reference component can be specified with extremely high accuracy.

The direction of the outline of the position reference component is as follows.
As in the case of the above-described chip, for example, the outline of the master image can be set as the temporary outline and the direction of the temporary outline can be determined.

Further, the master image can be created, for example, by photographing a chip or a position reference component of the same type as that used for the spark plug to be inspected under predetermined conditions.

The shape of the spark plug to be inspected is not particularly limited. For example, the following can be used. That is, the ground electrode has a shape in which the distal end is bent inward by bending so that the base end is coupled to the metal shell, while the side surface on the distal end faces the distal end surface of the center electrode. I do. The ground electrode-side tip is fixed to the tip side face, and faces the center electrode tip face or the center electrode tip fixed to the tip face. In this case, in the chip position information generation step, at least one of the following information is obtained. Information related to the distance a between the center axis of the tip of the ground electrode and the center point of the tip on the ground electrode side (the position reference component is the tip of the ground electrode). Here, the center point of the ground electrode-side tip means the geometric center of gravity of the captured image of the ground electrode-side tip (the same applies hereinafter). .Tips fixed to the ground electrode (ground electrode side chip)
Related to the distance b of the center point of the ground electrode from the tip surface of the ground electrode (the position reference component is the tip of the ground electrode). Information related to the opposing distance e between the tip surface of the center electrode or the opposing surface on the ground electrode side of the center electrode side tip and the opposing surface on the center electrode side of the ground electrode side tip (so-called spark gap interval: position reference) The constituent part is a center electrode or a center electrode side chip). As a result, it is possible to accurately obtain information that reflects the misalignment state or the eccentric state of the ground electrode side tip.

In the inspection information generating step or means, at least one of the following information may be generated based on the captured image of the ground electrode and the captured image of the center electrode. Information relating to the distance c between the center axis of the tip of the ground electrode and the center axis of the center electrode or the center axis of the center electrode side tip. Information relating to the distance d between the tip surface of the ground electrode and the center axis of the center electrode or the center axis of the center electrode side tip. By obtaining these pieces of information together, the gap formation state of the spark plug can be inspected more precisely.

It should be noted that it may be difficult to obtain information on the relative position between the position reference component and the chip, depending on the imaging direction of the imaging means. In this case, the spark plug is photographed from two or more different directions, and positional relationship information is generated from a photographed image of the chip and a photographed image of the position reference component from the plurality of directions.
For example, the shooting direction in which the center electrode and the ground electrode base end overlap each other so that the center electrode is on the front side and the base end of the ground electrode is on the rear side when viewed from the shooting means is the front shooting direction and the center electrode. Assuming that a photographing direction substantially orthogonal to the front photographing direction around the central axis is a lateral photographing direction, information related to the distance c is preferably generated from a photographed image in the front photographing direction. Further, information related to the distance e,
The information related to the distance d is preferably generated based on a photographed image in the side photographing direction.

On the other hand, depending on the type of spark plug,
Some of the ground electrode-side tips are buried in the ground electrode side, or even if a projecting portion is formed, it is difficult to identify the outer shape of the tip projecting portion due to a welding dripping portion or the like. In this case, if the bending of the ground electrode has been completed,
Shooting a chip can be difficult. Therefore, prior to bending the ground electrode, an image of the side surface of the ground electrode and the ground electrode side chip fixed to the side surface is obtained by photographing the spark plug from the above-described front photographing direction. If the pre-photographing step is performed (by the pre-bending photographing means), the positional relationship between the ground electrode and the ground electrode-side tip can be accurately grasped based on the photographed image.

For example, based on the photographed image obtained in the pre-bending photographing step, the information relating to the distance a and / or the information relating to the distance b can be obtained very easily. In this case, based on the information related to the distance a and the information related to the distance c, the center axis of the ground electrode-side chip in the ground electrode width direction, from the center axis of the center electrode or the center axis of the center electrode-side chip. Eccentricity information generating step of obtaining information on the amount of eccentricity (information on the amount of eccentricity of the ground electrode-side chip in the width direction). Also,
Based on the information related to the distance b and the information related to the distance d, the amount of eccentricity of the center axis of the ground electrode-side tip in the ground electrode axis direction from the center axis of the center electrode or the center axis of the center electrode-side tip. An axial eccentricity information generating step of generating information regarding the ground electrode side tip axial eccentricity amount information can also be performed. Thereby, even when the tip is buried in the ground electrode and the position of the chip on the ground electrode is difficult to be specified from the photographed image from the front photographing direction or the side photographing direction, for example, by performing the photographing process, By obtaining information related to the distances a and b, it is possible to accurately grasp the amount of eccentricity in each direction.

On the other hand, in the case of a spark plug in which the opposing surface on the center electrode side of the chip projects from the opposing surface on the center electrode side of the ground electrode and is fixed to the tip of the ground electrode, for example, The ground electrode is photographed from the above-described front photographing direction, and the ground electrode width is determined based on the photographed image of the protruding portion of the chip on the ground electrode side and the photographed image of the center electrode or the photographed image of the chip fixed to the center electrode. Information on the amount of eccentricity of the center axis of the ground electrode-side tip in the direction from the center axis of the center electrode or the center axis of the center electrode-side tip (ground electrode-side chip width direction eccentricity information) may be generated. Further, the ground electrode after bending is photographed from the above-mentioned lateral photographing direction, and a photographed image of the protruding portion of the ground electrode side chip and a photographed image of the center electrode or a photographed image of the chip fixed to the center electrode are formed. Based on the information on the amount of eccentricity of the center axis of the ground electrode-side tip in the direction of the ground electrode electrode from the center axis of the center electrode or the center axis of the center electrode-side tip (information on the amount of eccentricity in the axial direction of the ground electrode-side chip).
May be generated. However, also in this case, the distance a is determined based on the photographed image obtained in the photographing step before bending.
Alternatively, information relating to the distance b may be obtained, and the information of the eccentricity may be obtained using the values of a and b.

On the other hand, when a large part of the ground electrode side chip is buried in the ground electrode, the above-mentioned distance e (spark gap interval) may not be able to be determined accurately only by information of a photographed image. In this case, the method (or apparatus) of the present invention includes a ground electrode-side chip surface undulation state measuring step of measuring the surface undulation state of the ground electrode-side chip on the center electrode side facing surface before bending the ground electrode. (Or means)
Can be added. In this case, in the photographing step (or means), an image of the center electrode or the center electrode side chip and the ground electrode is taken after the ground electrode is bent. In addition, the inspection information generating step (or means) is based on the information of the measured surface undulation state of the surface facing the center electrode side of the ground electrode side chip and the information of the photographed image, and It is assumed that information relating to the distance e between the opposing surface of the chip on the center electrode side and the tip surface of the center electrode or the opposing surface of the center electrode side chip on the ground electrode side is generated as inspection information.

According to this, prior to bending of the ground electrode, the surface undulation state (for example, information such as surface roughness or surface displacement distribution) of the opposing surface on the center electrode side of the ground electrode side tip is obtained.
For example, even when the ground electrode-side tip is buried in the ground electrode, the distance e is determined based on the information of the surface undulation state and the center electrode or the image information of the center electrode-side tip and the ground electrode. Can be easily obtained. As a means for measuring the surface undulation state, a method in which the probe is brought into contact with the surface to be measured and the displacement of the probe when the probe is moved on the surface in that state is read, or a laser beam is applied. Various known methods such as a method of reflecting light on a measurement surface and measuring based on information of the reflected light can be adopted.

In the above method or apparatus, based on the obtained inspection information, the tip fixed to the ground electrode satisfies the desired positional relationship with the predetermined portion of the spark plug. It is possible to add a chip position determination step or means for determining whether or not there is a chip position, and a chip position determination result output step or means for outputting the determination result. As a result, it is possible to automatically judge the inspection results, and it is extremely unlikely that troubles such as omission of inspection due to human error will occur, and the efficiency of the inspection process including the judgment will be greatly improved. Can be. In this case, if the determination result is negative, a ground electrode correcting step or a ground electrode correcting step of performing a correcting process on the ground electrode so that the chip satisfies the desired positional relationship with respect to the predetermined portion of the spark plug. Means can be provided. This makes it possible to automatically correct a spark plug having a defect at the chip position, thereby improving the efficiency of the correction process and improving the production yield of the spark plug at the same time. .

[0030]

1 and 2 show a spark plug inspection apparatus according to the present invention (hereinafter simply referred to as an inspection apparatus).
1A and 1B are a plan view and a side sectional view conceptually showing one embodiment. That is, the inspection apparatus 1 moves the spark plug to be processed (hereinafter also referred to as a work) W through a circumferential path (transport path) C
A rotary conveyor 2 is provided as a transporting means for intermittently transporting the workpiece along a path, and along a circumferential path C thereof, a workpiece loading mechanism 11 as a processing target spark plug loading mechanism and a ground electrode of the workpiece W are positioned at predetermined positions. A work positioning mechanism (I) 12 for positioning, a photographing / analysis unit (I) 13 (imaging means before bending), a rejected product discharging mechanism (I) 14, a ground electrode bending machine 15, a work positioning mechanism ( II) 16;
Imaging / analysis unit (II) 17 and rejected product discharge mechanism (II)
18, a work 90 ° turning mechanism 19 for turning the work W by 90 ° around the axis of the center electrode, and a photographing / analysis unit (I
II) 20, a rejected product discharging mechanism (III) 21, and a product discharging mechanism 22 are arranged in this order. The arrangement positions of these mechanisms and the units 11 to 22 are the execution positions of the inspection processes on the workpiece W. The distance between each of these mechanisms and units is adjusted so as to be an integral multiple of the angle θ in units of a certain angle θ along the circumferential path C.

As shown in FIG. 1 (b), the rotary conveyor 2 has a disk-shaped transport rotating body 30 arranged substantially horizontally.
And a plurality of work holders 23 that detachably hold the processing target spark plug W fixed to the work holder H substantially horizontally, along the circumferential path C at intervals corresponding to the angle θ. Is formed. The transport rotator 30 is intermittently driven by the servo motor 34 as an intermittent drive unit in units of the angle θ via a rotation transmission mechanism (not shown). Thereby, the work W held by each work holding unit 23 is intermittently conveyed on the circumferential path C shown in FIG. 1 while sequentially stopping at the process execution positions by the mechanisms and the units 11 to 22. Becomes

As shown in FIG. 2, the workpiece carrying mechanism 11, the rejected product discharging mechanism (I) 14, the rejected product mechanism (II) 18, and the
(III) 21 and the product discharge mechanism 22 are, for example, a transfer mechanism for transferring the work W mounted on the work holder H between the work supply unit or the work discharge unit Q and the work holding unit 23 of the rotary conveyor 2. Be composed. The transfer mechanism 35 includes a chuck hand mechanism 36 held up and down by an air cylinder 37, an advance / retreat drive mechanism 39 for driving the chuck hand mechanism 36 to advance / retreat in the radial direction of the circumferential path C by an air cylinder 38, and the like. Be composed. The chuck hand mechanism 36 is driven to open and close by an air cylinder or the like (not shown).
To hold the work holder H (work W),
Then, after ascending, it is driven forward and backward by the air cylinder 38 to move to the transfer destination, where it is again lowered to move the work holder H
(Work W) is released and transfer is completed.

Next, returning to FIG.
(I) 13, (II) 17, and (III) 20 all have the same structure. Hereinafter, the imaging and analysis unit (I) 13 will be described with reference to the schematic diagram of FIG. That is, the photographing / analyzing unit (I) 13 includes a ring light 238 as an illuminating unit for illuminating the front end of the work W, a filter (for example, a polarizing filter) 239, and a photographing camera 40 as photographing means. It is held at a predetermined height. Here, the ring light 238,
The filter 239 and the photographing camera 40
Are arranged substantially concentrically in the optical axis direction. The electrical configuration of the analysis unit will be described later.

The photographing camera 40 is configured as a CCD camera having, for example, a two-dimensional CCD sensor as an image detecting unit, and is provided with a central electrode W2 of a horizontally held work W.
, A ground electrode W1, a center electrode W2 thereof, and a ground electrode W1.
And a spark gap g (FIG. 4) formed between them. Each of the photographing / analyzing units 13, 17, and 20 captures a reference body having a known dimension in advance so that the image magnification (for example, the value of the corresponding actual dimension per pixel) becomes a predetermined value. The height of each camera 40 is adjusted. Note that the image magnification may be the same value between the photographing / analysis units 13, 17, and 20, or may be different values between two or more units. Further, it is desirable that the photographing optical system of each photographing camera 40 be constituted by a telecentric optical system so that a change in image size due to defocus is reduced.

Next, in the spark plug W to be used in this embodiment, as shown in FIG. 4B, for example, the base end of the ground electrode W1 is coupled to the metallic shell W3, while the ground electrode W1 is The distal end has a shape bent inward by bending so that the side surface on the distal end faces the distal end surface of the center electrode W2. A ground electrode tip W4 is fixed to the tip side surface by welding, and faces the tip surface of the center electrode W2. Most of the ground electrode side chip W4 is buried in the ground electrode W1 side. In addition,
Each electrode is made of, for example, a Ni alloy, and the tip W4 is made of Pt or It.
It is mainly composed of a noble metal such as r.

When the spark plug W to be processed is carried in by the work carrying mechanism 11 (FIG. 1), the spark plug W shown in FIG.
As shown in (a), the ground electrode W1 is in a state before the bending process is performed. The spark plug W to be processed is placed on the work holder H such that the center electrode W2 is on the front side and the base end of the ground electrode W1 is on the rear side when viewed from the photographing camera 40 (FIG. 3). And the base end portion of the ground electrode W1 are mounted in a positional relationship in which they appear to overlap each other (that is, a positional relationship in which the photographing direction is the front photographing direction). Then, the ground electrode W1 is bent by the ground electrode bending machine 15 (FIG. 1) to obtain a state shown in FIG. 4B. Further, the workpiece 90 is turned 90 ° around the axis of the center electrode W2 by the work 90 ° turning mechanism 19, and FIG.
The state shown in (c), that is, the state in which the photographing direction is a side photographing direction substantially orthogonal to the front photographing direction, is maintained. It should be noted that, by turning 90 ° in the opposite direction, FIG.
The state shown in FIG.

Next, the electrical configuration of the inspection apparatus 1 will be described with reference to a block diagram. FIG. 5 is a block diagram illustrating a configuration of the main control unit 100 and its peripherals. The main control unit 100
An I / O port 101 and a CPU 102 connected thereto,
The microprocessor 103 includes a microprocessor including a ROM 103 and a RAM 104, and the ROM 103 stores a main control program 103a. And I / O
The drive unit 2c of the rotary conveyor 2 is connected to the port 101. The drive section 2c includes a servo drive unit 2a, a servo motor 34 for driving the rotary conveyor described above connected thereto, and an angle sensor 2b such as a rotary encoder for detecting a rotational angle position of the servo motor 34. It is composed of Also, I / O port 1
01 includes a storage device 105 composed of a hard disk device or the like in addition to the above-described mechanisms and units 11 to 22 and the like.
And an input unit 1 composed of a keyboard, a mouse, etc.
06 are connected.

FIG. 6 shows the photographing / analysis units 13, 17, and
FIG. 2 is a block diagram showing an example of an electrical configuration of the imaging and analysis unit 20 (hereinafter, the imaging and analysis unit 13 will be described as a representative). photograph·
The analysis unit 13 includes an I / O port 111, a CPU 112 connected to the I / O port 111, and a ROM 11
The ROM 113 stores an image analysis program 113a. Also, I / O port 11
1 includes a photographing camera 40 (two-dimensional CC) as photographing means.
D sensor 115 and a sensor controller 116 for converting the sensor output into a two-dimensional digital image input signal
And a storage device 115 as master image data storage means. The storage device 115 stores master image data 115a and dimension data 115b that gives a reference value for each inspection dimension described below. The RAM 114 stores a work area 114 a of the CPU 112, image data of the work W captured by the camera 40, and master image data and dimension data used for inspection of the work W.
b to 114d are formed. Note that the CPU 112
Is a main component of a chip determination unit, an inspection information generation unit, a chip position determination unit, and a chip position determination result output unit by the image analysis program 113a. Note that the master image data may be stored in the storage device 105 connected to the main control unit 100 in FIG. 5, and necessary data may be transferred to each of the photographing / analysis units 13, 17, and 20 for use each time.

Hereinafter, the operation of the inspection apparatus 1 will be described with reference to a flowchart. FIG. 7 shows a flow of each step of the inspection when focusing on one work W. However, in the present embodiment, as shown in FIG.
Each of the inspection processes is performed intermittently while receiving the instruction from the main control unit 100 shown in FIG.
To 22 in parallel. Therefore, each step of the flowchart of FIG. 7 is not necessarily executed sequentially by one program routine.

That is, as shown in FIG. 1, the work W loaded into the rotary conveyor 2 by the work loading mechanism 11 and mounted on the work holding portion 23 is positioned at a predetermined position by the work positioning mechanism (I) 12. The image of FIG. 4A is photographed by the photographing / analysis unit (I) 13 (FIG. 7: S1, S2). Then, image processing / dimension inspection 1 is performed in S3 of FIG.

FIG. 8 shows the flow of the image processing / dimension inspection 1 process. First, in S51, a front image of the ground electrode W1 before bending is recognized. As shown in FIG. 19, what is recognized in the process is the outline position of each front image of the tip end of the ground electrode W1 before bending and the ground electrode side tip W4. FIG.
Shows the flow of the image recognition process. That is,
The captured image data of the ground electrode W1 is taken in, the corresponding master image data is read out from the storage device 115 (FIG. 6), and the memories 114b and 114c of the RAM 114 are read out.
(FIG. 9: S101, S102).

The master image is created, for example, by previously photographing a spark plug component to be inspected under predetermined conditions. For example, as shown in FIG. 17, in the case of a square photographed image 51 such as a ground electrode, master images 50 corresponding to respective corners are prepared, and the outlines of components used for dimension measurement are prepared from these. Items necessary for the decision are appropriately selected and used. Here, the master image 50 and the photographed image 51 are each formed as a so-called gray scale image by a combination of output states of a plurality of pixels capable of outputting an intermediate density.

The master image 50 is searched for a suitable position between the master image 50 and the photographed image 51 while moving in parallel between respective positions on the pixel plane of the photographed image 51. That is, FIG.
As shown in (a), a density difference (or its absolute value) between corresponding pixels is calculated between a master image 50 positioned at a predetermined position on a pixel plane and a captured image 51 overlapping the master image 50. , And calculate the total (or average value). Then, a photographed image portion in which the value of the total calculated for each position is minimum is selected as a suitable portion (FIG. 9:
S104 to S107). For example, when the imaging target is a chip, the matching portion is a chip image portion. Also, S
At 108, the master image 50 is positioned in a state of being superimposed on the above-mentioned conforming portion, and the outline is set as a temporary outline, and the process proceeds to S109, where a predetermined position (hereinafter, referred to as an edge position) on the outline by the edge tool is determined. This is a confirmation process.

FIG. 10 shows the flow of the edge position determination processing. First, a temporary edge position is determined on the outline of the master image 50, and a pixel matrix 60 having a fixed size as shown in FIG. 18A is determined.
The density value of each pixel is read as shown in FIG.
151, S152). Then, the direction parallel to the temporary outline is defined as the row direction (corresponding to the outline direction in the claims), and the direction perpendicular to the column direction is defined as the column direction, and the density values of the pixels are totaled for each row (S153: The sum of the values is called the density value level). Next, the process proceeds to S154 and S155 in FIG. 10, and a position where the rate of change of the density value level gi of each pixel P in the column direction is maximum is determined as an edge position. That is, as shown in FIG. 18 (c), a difference operation between the column direction adjacent values of gi is performed, and a position where the difference is maximum is defined as an edge position. Note that a certain threshold value may be determined for the density value level gi, and a pixel position in the column direction that changes from one of a state larger than the threshold value and a state smaller than the threshold value to the other may be set as the edge position.

Returning to FIG. 8, as the outlines of the ground electrode W1, both edges E1 and E2 in the width direction of the ground electrode W1 and the front edge E3
(FIG. 19) is determined by the above method. In this case, in order to determine each outline, at least two points on the outline determined by the edge position determination processing are required, but three or more points are used to improve accuracy, and linear regression is performed on these points. It may be. Then, when each outline is determined, the coordinates of the intersection point can be calculated. In this process, the coordinates of both end points T1, T2 of the leading edge E3 are calculated, and the coordinates (xt, yt) of the midpoint T3 are calculated (S52, S53).

Then, the process proceeds to S54 in FIG. 8, and the outer shape of the axial end face of the ground electrode side chip W4 is similarly recognized. In this case, as shown in FIG. 20A, the master image 50 is matched with the captured image of the ground electrode side chip W4,
As shown in (b), three points on the outline are determined by the same edge determination processing as described above, and a circle R passing through these three points is determined as the final outline of the ground electrode side chip W4.
At the same time, the coordinates (x0, y0) of the center OO of the circle R are also calculated (FIG. 8: S55). And, as shown in FIG.
The distance a between the center OO, that is, the center axis O2 of the ground electrode side tip W4 and the center axis O1 of the ground electrode W1 is represented by a = a
xt-x0. Further, the distance b from the tip edge (tip face) E3 of the center axis of the ground electrode side tip W4 is represented by b =
It is determined by yt-y0 (S56).

In order to determine the outer shape of the axial end face of the ground electrode side chip W4 with higher accuracy, a plurality of sets of three different points on the outer shape are determined, and a plurality of circles passing through each of the three points are determined. The center position and the radius of the circle are respectively defined, and the final outline of the axial end face of W4 is defined as a circle having the center and the radius as the average center positions and the average radii of the plurality of circles, respectively. It is desirable to determine. The processing in this case will be described based on the step explanatory diagram of FIG. 32 and the flowchart of FIG.

First, in S301 of FIG. 33, an image of the outline of the axial end face of the ground electrode side tip W4 is taken.
Next, in S302, as shown in FIG. 32A, the temporary center Ov of the chip outline is determined by adapting the master image 50 to this. Here, if the total K of the absolute values of the density differences between the corresponding pixels between the captured image and the master image 50 exceeds a predetermined reference value K0, S
Proceeding to 313, a failure determination is made in which the ground electrode side chip W4 is absent.

On the other hand, if K is equal to or smaller than K0, the process proceeds to S305, and as shown in FIG. 32B, the predetermined angular interval γ is determined by the above-described edge position determination processing centering on the temporary center Ov.
An outline point (edge position) EC is determined at (for example, 2 ° intervals) (S305). Then, as shown in FIG. 32 (c), each outline point EC is set as a reference point (indicated by a circle in the figure) and
It is selected as an outline point (indicated by △ in the figure) located at a position deviated by an angle β (for example, 44 °) to the left and right of the reference point, and passes through the selected two points and the reference point, for a total of three points The center O 'and the radius r' of the circle are calculated (S307). If the determined r 'deviates from the standard specification range (for example, the lower limit value rmin and the upper limit value rmax) of the chip in S308, it is regarded as defective, the defective circle counter Np is incremented by 1 (S309), and the process proceeds to S310. The count value of the defective circle counter Np is compared with a reference value N0 (for example, 30).

If the failure circle count value Np exceeds the reference value N0 in S310, the flow advances to S313 to make a failure determination that the ground electrode side chip W4 is absent. On the other hand, if the count value of the defective circle counter Np is equal to or smaller than the reference value N0, the process proceeds to S311 to calculate the center O 'and the radius r' of the three-point circle for all the outline points EC. After the calculation of the center O ′ and the radius r ′ of the three-point circle for all the outline points E C in S311 in this way, S31 is completed.
4 and the calculated center coordinates O′i (= (x
i, yi), i = 1, 2, ‥‥, n) and the radius r′i
The average value of (i = 1, 2,..., N) is determined as the center O and the radius r of the outline of the axial end surface of the ground electrode side tip W4, and the process ends.

Next, returning to FIG. 8, the inspection determining step of S57 is performed. In the present embodiment, as shown in FIG. 14, a value obtained by adding a preset inspection error α to each of the absolute values a and b, that is, | a | + α, or | b | + α falls within a specified range. If it passes, it will be rejected. The data in the specified range is read from the dimension data 115b in FIG. 6 and used.

In the above processing, the photographing / analysis unit (I) 13 includes the photographing camera 40 as photographing means,
A storage device 115 as master image data storage means,
A CPU 112 is provided as a chip discriminating unit, a test information generating unit, and a test information output unit, and finally generates values a and b as position information of the chip W4. Therefore, it can be considered that the imaging / analysis unit (I) 13 alone constitutes the inspection apparatus of the present invention.

Returning to FIG. 7, if the result of the inspection is reject, a reject notification is displayed on the monitor 107 or the like connected to the I / O port 101 in FIG.
(I) The work W rejected by 14 (FIG. 1) is discharged, and after the work W is confirmed to be taken out, the process is terminated (S4 → S15 to S17: Hereinafter, this routine will be performed to discharge the rejected product). Routine). On the other hand, if it passes, the process proceeds to S5 and thereafter, and the ground electrode W1 is used by the ground electrode bending machine 15 in FIG.
Is bent (S5), and the workpiece positioning mechanism
After repositioning the work W in (II) 16 (S6), the image of FIG. 4B is photographed by the photographing / analysis unit (II) 17 (S7). Then, the image processing / dimension inspection 2 is performed in S8 of FIG.

FIG. 11 shows the flow of image processing / dimension inspection 2. This processing is basically performed based on a combination of the matching processing with the master image and the edge position determination processing (hereinafter, referred to as gray search processing) using an edge tool, similar to the image processing / dimension inspection 1.
The outline will be described with reference to FIG. That is, both edges E4 and E5 of the end surface of the ground electrode W1 photographed in front and the edge E6 facing the center electrode W2 are determined, and the coordinates of the both ends T4 and T5 of E6 are obtained from the intersection thereof. T6 coordinates (x
k, yk). Further, both edges E7, E8 of the center electrode W2.
Then, the edge E9 is determined, and the coordinates of both end points T7 and T8 of E9 are obtained from the intersection thereof, and the coordinates (xl, yl) of the middle point T9 of E9 are obtained. Then, the distance c between the center axis of the ground electrode W1 and the center axis O3 of the center electrode W2 is represented by c = x
k-xl (FIG. 11: S201 to S20)
7).

The front edge (front surface) E9 of the center electrode W2.
Distance e between the ground electrode side tip W4 and the opposite surface e
(Spark gap interval) in a predetermined direction (eg, ground electrode W
(In a direction substantially parallel to both edges E4 to E5) of the center electrode W2 (in a direction substantially parallel to both edges E4 to E5) of the center electrode W2 and the opposite edge E6 of the ground electrode W1. (S208). Then, an inspection is determined in S209. That is, if | c | + α (or | e | + α) is within the specified range, the test is passed, and if not, the test is rejected (FIG. 15A: J51 to J53).

Returning to FIG. 7, in S9, the rejected product is S
As in the case of No. 4, the process is returned to the rejected product discharging routine of S15 to S17 (the discharging is performed by the rejected product discharging mechanism (II) 18 in FIG. 1). On the other hand, if it passes, proceed to S10 and work 90 °
The work position is turned 90 ° by the turning mechanism 19 to
4 (c) (or FIG. 4) by the analysis unit (III) 20.
The image of (d) is photographed (S11). And S12
The image processing / dimensional inspection 3 is performed.

FIG. 12 shows a flow of the image processing / dimensional inspection 3. This processing is also executed based on a combination of the matching processing with the master image and the edge position determination processing by the edge tool. The outline will be described with reference to FIG. That is, the ground electrode W1 photographed sideways
And the edge E11 facing the central electrode W2 is determined, and the intersection (x) of the tip T10 of E11 is determined by their intersection.
5, y5). Further, both edges E12, E1 of the center electrode W2.
3 and the leading edge E14 are determined, the coordinates of the two end points T11 and T12 of E14 are obtained from their intersection, and the middle point T13 of E14 is further determined.
(Xm, ym) are obtained. Further, the facing distance e (spark gap interval) between the leading edge (tip surface) E14 of the center electrode W2 and the facing surface of the ground electrode tip W4 is set to a predetermined direction (for example, approximately equal to the leading edge E10 of the ground electrode W1). Parallel direction)
Is determined as the minimum value of the distance between the tip edge (tip face) E14 of the center electrode W2 and the opposing edge E11 of the ground electrode W1. Further, the distance d between the tip edge (tip face) E10 of the ground electrode W1 and the central axis O3 of the center electrode W2 is determined by d = x5-xm (above, S251 to S257). The eccentricity f between the center axis O3 of the center electrode W2 and the center axis of the ground electrode side tip W4 may be calculated as f = x5-xm-b. (S258). Then, the inspection is determined in S259. That is, | d | + α, | e | + α (or |
f | + α) falls within the specified range, and fails if not. (FIG. 16 (a): J101 to J10)
4).

Returning to FIG. 7, in S13, the rejected product is sent to the rejected product discharging routine in S15 to S17 in the same manner as in S4 (discharging is performed by the rejected product discharging mechanism (III) 21 in FIG. 1).
Do). On the other hand, if it passes, the process proceeds to S14, and a success notification is made, and the product is discharged by the product discharging mechanism 22 of FIG. The work holding unit 23 of the work W is returned to the work loading position by the rotation of the rotary conveyor 2, and the inspection is repeated by the same steps as described above.

In the above process, the rejected product is only discharged by the rejected product discharging mechanism. For example, for the work W in which the values of c or d do not satisfy the specified range, the rejected product is discharged. It is also possible to correct the ground electrode W1 so that it falls within the specified range by correcting the ground electrode W1. When the correction is performed, as shown in FIGS. 1 and 5, a correction mechanism (I) 60 (ground electrode correction means) for correcting the width direction position of the ground electrode W1, and the axial position of the ground electrode W1 similarly. At least one of a straightening mechanism (II) 61 (ground electrode straightening means) for performing the straightening.

FIG. 23 conceptually shows a configuration example of the correction mechanism (I) 60. That is, the straightening mechanism (I) 60 is provided with a first holding portion 71 for holding and fixing the base end of the ground electrode W1.
And a second gripper 70 that grips the distal end side. Then, with the base end side gripped by the first gripping part 71, the tip side of the ground electrode W1 is set to be substantially parallel to the central axis of the center electrode W2 by the torsion drive part 72 via the second gripping part 70. By applying a torsional force around the torsion axis, the position of the ground electrode W1 in the width direction is corrected.
On the other hand, FIG. 24 shows a configuration example of the correction mechanism (II) 61. That is, the correction mechanism (II) 61 includes a work holding unit 73 that holds the work W so that the center electrode W2 does not move.
A tip grip 74 provided to be slidable in the axial direction of the ground electrode W1 by the guide 75, and gripping the tip of the ground electrode W1, and a proximal grip 76 holding the base of the ground electrode W1. Having. Then, with the distal end gripped by the distal end gripping part 74, the torsional drive part 77 through the base end gripping part 76 causes a predetermined axis (which is orthogonal to the paper surface) to be perpendicular to the axis O4 of the ground electrode W1 and the axis O5 of the center electrode W2. By applying a torsional force to the ground electrode W1 of the work W held by the work holding portion 73 around the (orthogonal axis), the axial position of the ground electrode W1 is corrected.

The processing flow in this case is as shown in FIG. 13, for example. That is, the processes in S1 to S16 are substantially the same as those in FIG. 7, but for the work W determined to be rejected in S9 to S15, it is determined whether the values of c to d can be corrected (S22). , S2
4) If the correction is possible, the correction processing is performed (S21, S2)
3). Note that the process may directly proceed to the correction processing without performing the determination of the possibility of correction. In any case, in the image processing / dimension inspection 2 to the image processing / dimension inspection 3 of FIGS. 11 and 12, correction value calculation steps S210 to S260 are performed.
Is added. One example of the processing is shown in FIGS.
As shown in FIG. 6 (b), the detected values of c to d are compared with the respective specified ranges, and if correction is impossible, a rejection judgment is made. If correction is possible, detected c or d is detected. The correction mechanism (I) 60 or the correction mechanism (II) such that the deviation between the value of d and the specified value is reduced to fall within the specified ranges.
A correction value to be instructed to 61 is calculated and set.

Here, the correction mechanism (I) 60 or the correction mechanism
(II) After the correction processing by 61, the inspection can be performed again to confirm whether or not the above-mentioned values of c to d satisfy the specified range. In this configuration, the correction mechanism
It is necessary to provide a new imaging / analysis unit on each downstream side of (I) 60 or the correction mechanism (II) 61. If the inspection shows that the value of c or d does not satisfy the specified range, the work W is discharged as a rejected product, or the second stage correction is performed. Can be. When performing the second-stage correction, a new correction mechanism is added, or the work is returned to the upstream correction mechanism manually or the like, and the correction is performed again.

In the above processing, each value of a to e is individually inspected to determine whether or not each value is within a specified range. However, the information of the distance a and the distance c Based on this information, the amount of eccentricity of the center axis of the ground electrode-side tip W4 in the width direction of the ground electrode W1 from the center axis of the center electrode W2 may be calculated as the inspection information. Further, based on the information on the distance b and the information on the distance d, the amount of eccentricity of the center axis of the ground electrode-side tip W4 in the direction of the ground electrode axis from the center axis of the center electrode W2 is calculated as inspection information. It may be.

FIG. 25 shows an example of the processing in this case. That is, the processing of S1 to S14 is almost the same as that of FIG. 7, but the values of a to c are measured in the image processing / dimension inspection 1 and 2; : S57, FIG. 11: S209) are omitted. Instead, the inspection determination process S259 in the image processing / dimension inspection 3 of FIG. 12 is as shown in FIG. That is, according to the measured values of a to d, the eccentricity in the width direction is set to a
+ C, and the axial eccentricity is calculated by b−d (J151 to J153). The value of e is used as it is. Then, | a + c | + α, | b−d
If each value of | + α and | e | + α falls within the specified range, it is judged as pass, and if not, it is judged as reject (J154 to J1).
58). If | a + c | + α does not fall within the specified range, the correction mechanism (I) 60 is adjusted so that | a + c | + α falls within the specified range.
May be used to correct the width of the ground electrode W1 in the width direction. If | b−d | + α does not fall within the specified range, the grounding electrode W1 may be corrected in the axial direction by the correction mechanism (II) 61 so that | b−d | + α falls within the specified range.

Next, as shown in FIG. 27, the ground electrode side tip W4 has an edge (facing surface) E30 facing the center electrode W2.
The ground electrode W1 may be fixed so as to protrude from the opposing surface E32 on the center electrode side of the ground electrode W1. At this time, the ground electrode W1 after bending is photographed from the front photographing direction, the coordinates of the midpoint of the opposing edge E30 of the chip W4 are (xp, yp), and the tip edge E31 of the center electrode W2 is determined by the above-described gray search method. If the coordinates of the midpoint are obtained as (xr, yr), the center electrode W2 of the center axis of the ground electrode-side chip W4 in the width direction of the ground electrode W1 can be obtained.
Of the eccentricity from the central axis (ie, the eccentricity in the width direction) c ′
Can be determined directly as c '= xp-xr.
In this case, the imaging / analysis unit (II) 17 can be omitted. If the contrast between the image of the protruding portion of the chip W4 and the image of the ground electrode W1 is relatively large, it is also possible to discriminate the two by ordinary binarization processing.

As shown in FIG. 28, the center electrode W2
The center electrode side tip W5 may be fixed to the tip end surface of the first electrode. In this case, the value of c 'or the value of d is:
The measurement is performed not on the center axis of the center electrode W2 but on the center axis of the center electrode side tip W5. For example, the above c ′
Is the tip edge E32 of the center electrode tip W5 (tip face,
Alternatively, the coordinates of the middle point of T32 (x
l, yl) is determined as c '= xp-xl. Further, based on the image of the center electrode W2 and the image of the center electrode side chip W5, the distance between the center axes of the two (that is, the amount of eccentricity) may be calculated as inspection information. In this case, the amount of eccentricity is, for example, as the amount of eccentricity δ1 in the width direction of the ground electrode W4, as shown in FIG. 29A, or the amount of eccentricity in the axial direction of the ground electrode W4, as shown in FIG. It can be calculated as the quantity Δ2.
When the center electrode side tip W5 is provided, the ground electrode side tip W4 may not be particularly provided.

On the other hand, as shown in FIG. 22, when a large part of the ground electrode side tip W4 is buried in the ground electrode W1, the above-mentioned distance e (spark gap interval) can be determined only by the information of the captured image. Sometimes it cannot be determined accurately. In particular, when the ground electrode side tip W4 is fixed by laser welding, the tip surface is easily roughened, and the measurement of e becomes more difficult. In this case, prior to the bending of the ground electrode W1, the surface undulation state of the surface facing the center electrode W2 side of the ground electrode side tip W4 is measured by the surface undulation state measuring device 200 shown in FIG. Photographed after processing,
The distance e may be measured based on the image of the center electrode W2 or the center electrode side tip W5 and the ground electrode W1, and the surface undulation information.

As shown in FIG. 30A, for example, as shown in FIG. 30A, the probe 201 is brought into contact with the surface Si to be measured of the tip W4 on the ground electrode side. The probe 2 when moved on Si
01, or a method in which a laser beam L from a light source 202 is reflected on a surface to be measured Si, the reflected light is received by an optical sensor 203 such as a CCD sensor, and measurement is performed based on the detection information. Various known devices can be adopted. For example, when the laser light L is irradiated while changing the distance between the light source 202 and the surface to be measured Si, the reflection angle of the reflected light, and thus the light receiving position on the optical sensor 203, reflects the undulating state of the surface to be measured Si. Because it changes
From the information, the displacement at each position on the surface to be measured Si can be read.

In this case, the opposing edge Ek of the ground electrode W1 is determined by the above-mentioned gray search method, and as shown in FIG.
The undulation amount h 'at each position on the measured surface Si with reference to the facing edge Ek can be measured. After the bending of the ground electrode W1, the corresponding undulation amount is obtained from the distance d0 at each position between the opposing edge (opposing surface) Ej of the center electrode W2 and the opposing edge Ek (or an extension thereof) of the ground electrode W1. h '
Is reduced, the distance between the opposing surfaces of the ground electrode tip W4 and the center electrode W2 at that position can be calculated by d0-h '. Then, for example, the minimum value of d0-h 'may be determined as e. Note that, even when the center electrode side tip W5 is provided, e
Can be determined.

In the above embodiment, the work W is conveyed intermittently along the circumferential path C. However, the work W may be conveyed intermittently along a linear path.
FIG. 31 shows an example thereof. That is, in this configuration, the carrier 302 for detachably attaching the work holder 23 to the chain 301 as a circulating member is provided.
Are mounted at predetermined intervals, and are intermittently driven by a motor 305, thereby intermittently transporting each work holder 23 along a predetermined linear path.
1 is formed. And along that straight path,
The above-described work loading mechanism 11, work positioning mechanism (I) 1
2. Imaging / analysis unit (I) 13, rejected product discharge mechanism (I)
14, ground electrode bending machine 15, work positioning mechanism (I
I) 16, photographing / analyzing unit (II) 17, rejected product discharging mechanism (II) 18, work 90 ° turning mechanism 19, photographing / analyzing unit (III) 20, rejected product discharging mechanism (III) 21, and The product discharge mechanisms 22 are arranged at predetermined intervals. Then, similarly to the configuration in FIG.
The arrangement position of 2 is an execution position of each inspection process on the workpiece W.

In the above embodiment, the photographing / analyzing units (I) 13, (II) 17, and (III) 20 photograph a spark plug component to be inspected as a gray scale image. If there is sufficient contrast between the inspection target portion and its background portion (or adjacent portion), the above-described gray search process is not performed, and the image is binarized to perform a simpler process. You may.
For example, as shown in FIG. 4 (c) or (d), when the spark plug (work) W is photographed from the side, another component is placed behind each outline of the component used for inspection. Since there is no space, the photographing / analysis unit (III) 20 (FIG. 1 and the like) for photographing the space can be configured to perform the above-described binarization processing. in this case,
If the image is silhouetted by illuminating the work W from behind with a backlight, a clearer contrast can be obtained, which is convenient for the binarization processing.

[Brief description of the drawings]

FIG. 1 is a plan view and a side sectional view schematically showing an embodiment of a spark plug inspection device according to the present invention.

FIG. 2 is a schematic view of a transfer mechanism.

FIG. 3 is a schematic diagram of an imaging / analysis unit.

FIG. 4 is a schematic view showing an example of a captured image of a spark plug to be processed.

FIG. 5 is a block diagram showing an example of an electrical configuration of a main control unit of the spark plug inspection device.

FIG. 6 is a block diagram showing an example of an electrical configuration of the imaging / analysis unit.

FIG. 7 is a flowchart showing a flow of a spark plug inspection process.

FIG. 8 is a flowchart showing the flow of processing of image processing / dimension inspection 1.

FIG. 9 is a flowchart illustrating the flow of an image recognition process.

FIG. 10 is a flowchart showing the flow of an edge position determination process.

FIG. 11 is a flowchart showing the flow of processing of image processing / dimension inspection 2;

FIG. 12 is a flowchart showing the flow of image processing / dimension inspection 3 processing.

FIG. 13 is a flowchart showing a flow of an inspection process when correcting a ground electrode.

FIG. 14 is a flowchart showing the flow of an inspection determination routine of image processing / dimension inspection 1;

FIG. 15 is a flowchart showing the flow of an inspection determination routine and a correction value calculation routine of image processing / dimension inspection 2;

FIG. 16 is a flowchart showing a flow of an inspection determination routine and a correction value calculation routine of image processing / dimension inspection 3;

FIG. 17 is an explanatory diagram illustrating the concept of a matching process between a master image and a captured image.

FIG. 18 is an explanatory diagram illustrating the concept of edge determination processing.

FIG. 19 is an explanatory diagram showing image processing contents of image processing / dimension inspection 1.

FIG. 20 is an explanatory diagram of a method for determining the outline of the ground electrode-side chip.

FIG. 21 is an explanatory view showing image processing contents of image processing / dimension inspection 2.

FIG. 22 is an explanatory diagram showing image processing contents of image processing / dimension inspection 3;

FIG. 23 is a conceptual diagram showing an example of a correction mechanism.

FIG. 24 is a conceptual diagram showing another example.

FIG. 25 is a flowchart showing the flow of a modified example of the spark plug inspection step.

FIG. 26 is a flowchart showing a flow of an inspection determination routine of the image processing / dimension inspection 3;

FIG. 27 is an explanatory view showing the contents of a modification of the image processing of the image processing / dimension inspection 2;

FIG. 28 is an explanatory diagram showing the contents of another modification of the image processing / dimension inspection 2 image processing.

FIG. 29 is an explanatory diagram in the case of measuring the amount of eccentricity between the center electrode and the center electrode side tip.

FIG. 30 is an explanatory diagram showing an example of a method of inspecting a spark gap amount in a case where surface irregularities of a ground electrode tip are taken into consideration.

FIG. 31 is a plan view and a side view schematically showing a modified example of the spark plug inspection device of the present invention.

FIG. 32 is a process explanatory view showing another example of the method for determining the outline of the ground electrode-side chip.

FIG. 33 is a flowchart showing the flow of the process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Spark plug inspection device W Spark plug to be processed W1 Ground electrode W2 Center electrode W3 Metal shell W4 Ground electrode tip W5 Center electrode tip 13 Photographing / analysis unit (I) (photographing means, spark plug inspection device) Unit (II) (imaging means) 20 imaging / analysis unit (III) (imaging means, spark plug inspection device) 40 imaging camera (imaging means) 112 CPU (chip discriminating means, inspection information generating means,
Chip position determination means, chip position determination result output means)

Claims (25)

[Claims] 1. A center electrode, a ground electrode disposed so that a tip side faces the center electrode, and a chip fixed to at least one of the center electrode and the ground electrode to form a spark gap. A method for inspecting a spark plug, wherein an image of at least the chip and a portion of the center electrode or the ground electrode to which the chip is fixed (hereinafter, referred to as a chip fixing portion) is obtained. In a photographing step of photographing the plug, in the photographed image, a master image having a shape corresponding to all or a part of the chip is prepared in advance, and by searching for a part matching the master image in the photographed image, A chip discriminating step of discriminating a compatible part as a part forming at least a part of the chip, and a photographed image of the discriminated chip and the chip An inspection information generating step of generating inspection information on at least one of the size and the position of the chip based on at least one of the master image positioned so as to be superimposed on the conforming portion; and the generated inspection information. And c. Outputting a test information output step. 2. A semiconductor device comprising: a center electrode; a ground electrode disposed so that a front end side faces the center electrode; and a chip fixed to at least one of the center electrode and the ground electrode to form a spark gap. A method for inspecting a spark plug, comprising: photographing a ground electrode-side chip fixed to the ground electrode and the center electrode; photographing a center electrode-side chip fixed to the center electrode and the ground electrode; A photographing step of photographing the ground electrode-side chip fixed to the center electrode and the center electrode-side chip fixed to the center electrode, and / or photographing the center electrode and the center electrode-side chip fixed to the center electrode. In the photographed image, an image of the chip and a portion of the center electrode or the ground electrode to which the chip is fixed (hereinafter, referred to as a chip fixing portion) is determined. Information on the amount of eccentricity between the ground electrode-side tip and the center electrode, information on the amount of eccentricity between the ground electrode and the center electrode-side tip based on the image information after the determination. A test for generating at least one of information on an eccentricity between the ground electrode-side tip and the center electrode-side tip and information on an eccentricity between the center electrode-side tip and the center electrode as test information. A spark plug inspection method, comprising: an information generation step; and an inspection information output step of outputting the generated inspection information. 3. In the chip discriminating step, a master image having a shape corresponding to all or a part of the chip is prepared in advance, and a portion compatible with the master image in the photographed image is searched for, thereby obtaining the photographed image. Determining a compatible part of the image with the master image as a chip image part forming at least a part of the chip; in the inspection information generating step, the determined chip image part is superimposed on the chip image part; 3. The spark plug inspection method according to claim 2, wherein inspection information relating to at least one of the size and the position of the chip is generated based on at least one of the master image positioned in the step (a). 4. The photographed image and the master image,
It is formed by a combination of output states of a plurality of pixels capable of outputting an intermediate density, and in the captured image, a portion in which the total density difference between the corresponding pixels with the master image is minimized is the matching portion 4. The spark plug inspection method according to claim 1, further comprising the step of selecting the chip as a chip. 5. A position in which the density value level of each pixel changes from one of a state larger than a predetermined threshold and a state smaller than the threshold to the other in a direction intersecting with the chip outline direction, or the chip. The position where the rate of change of the density value level of each pixel of the chip image portion or each pixel of the master image, which is detected along the direction intersecting the outline direction, is the maximum, and the outline position of the chip. 5. The spark plug inspection method according to claim 4, further comprising a step of generating a chip outline information determined as: 6. The chip has a circular axial cross section. In the chip determining step, the circular master image is adapted to a photographed image of an axial end face of the chip. 6. The spark according to claim 5, wherein in the outline information generation step, three different points are determined as outline positions on the axial end surface of the chip, and a circle passing through the three points is determined as the outline line of the axial end surface. Plug inspection method. 7. A plurality of sets of three points different from each other are determined, a center position and a radius of a plurality of circles passing through each of the three points are determined, and a final outline of an axial end face of the chip is defined as:
7. The spark plug inspection method according to claim 6, wherein the average center position and the average radius of the plurality of circles are defined as circles having the center and the radius, respectively. 8. In the photographing step, the chip is used to inspect a positional relationship between the chip and a predetermined component of the spark plug (hereinafter, referred to as a position reference component) that provides a position reference for the chip. An image of the position reference component is also taken, and the inspection information generating step is based on the image of the chip and the image of the position reference component, and the positional relationship of the chip with respect to the position reference component. 8. The spark plug inspection method according to claim 1, further comprising a chip position information generating step of generating information. 9. In the photographing step, the spark plug is photographed from two or more different directions, and in the inspection information generating step, a photographed image of the chip and a photographed image of the position reference component from the plurality of directions. The spark plug inspection method according to claim 8, wherein the positional relationship information is generated by the following. 10. The ground electrode is bent inward by a bending process so that a base end side is coupled to the metal shell while a front end side faces a front end surface of the center electrode. And the ground electrode-side tip is fixed to the tip side surface, and in the tip position information generating step, the position reference component is used as the tip of the ground electrode.
The center axis of the ground electrode tip and information related to the distance a between the center point of the ground electrode tip and the position reference component as the tip of the ground electrode,
Information related to the distance b between the center point of the ground electrode-side tip and the tip surface of the ground electrode, and the position reference component portion as the center electrode or the center electrode-side tip, and the tip surface of the center electrode or the At least one of information relating to a facing distance e between a ground electrode side facing surface of the center electrode side tip and a center electrode side facing surface of the ground electrode side tip is generated as the tip position information. The spark plug inspection method according to claim 8 or 9, wherein 11. The test information generating step includes the step of: generating a center axis of the ground electrode tip, a center axis of the center electrode, or the center electrode based on the shot image of the ground electrode and the shot image of the center electrode. Information relating to a distance c from the center axis of the side tip; and information relating to a distance d between the tip surface of the ground electrode and the center axis of the center electrode or the center axis of the center electrode side tip. The spark plug inspection method according to any one of claims 8 to 10, further comprising an auxiliary inspection information generation step of generating any of the auxiliary inspection information. 12. The photographing direction in which the center electrode and the ground electrode base end overlap each other so that the center electrode is on the front side and the base end of the ground electrode is on the rear side when viewed from the photographing means. Frontal photographing direction, around the central axis of the center electrode, a photographing direction substantially orthogonal to the frontal photographing direction is defined as a lateral photographing direction, and information related to the distance c is generated based on the photographed image in the frontal photographing direction. 12. The spark plug inspection method according to claim 10, wherein at least one of the information related to the distance e and the information related to the distance d is generated based on a captured image in the side capturing direction. 13. The photographing direction in which the center electrode and the ground electrode base end overlap each other so that the center electrode is on the front side and the base end of the ground electrode is on the rear side when viewed from the photographing means. As the front photographing direction, the photographing step is to photograph the spark plug from the front photographing direction before performing the bending process on the ground electrode, so that the side surface of the ground electrode and the side surface The spark plug inspection method according to any one of claims 8 to 11, further comprising a pre-bending photographing step of obtaining an image with the fixed ground electrode side tip. 14. The chip position information according to claim 13, wherein at least one of the information related to the distance a and the information related to the distance b is generated based on a captured image obtained in the pre-bending imaging step. The described spark plug inspection method. 15. The test information generating step, wherein, based on the information related to the distance a and the information related to the distance c, the center axis of the ground electrode-side chip in the ground electrode width direction, A width direction eccentricity information generating step of generating a ground electrode side chip width direction eccentricity amount information relating to the amount of eccentricity from the center axis of the center electrode or the center axis of the center electrode side chip, and information relating to the distance b; A ground electrode that is based on information related to the distance d and that is related to the amount of eccentricity of the center axis of the ground electrode-side tip in the ground electrode axial direction from the center axis of the center electrode or the center axis of the center electrode-side tip. 12. The spark plug inspection method according to claim 11, further comprising: an axial eccentricity information generating step of generating the side tip axial eccentricity amount information. 16. The imaging device according to claim 16, wherein a ground electrode side tip of the ground electrode side tip has a center electrode side facing surface that is more protruding than a center electrode side facing surface of the ground electrode. In the step, the photographing direction in which the center electrode and the ground electrode base end overlap each other is viewed from the front so that the center electrode is on the front side and the base end of the ground electrode is on the rear side when viewed from the photographing means. As the photographing direction, the ground electrode after bending is photographed from the front photographing direction. In the chip position information generating step, a photographed image of the protruding portion of the ground electrode-side chip and a photographed image of the center electrode or the center Based on the captured image of the chip fixed to the electrode, whether the center axis of the ground electrode-side chip in the ground electrode width direction, the center axis of the center electrode, or the center axis of the center electrode-side chip. Amount of eccentricity about the spark plug inspection method according to any one of claims 8 to 15 ground electrode tip width direction eccentricity information is generated. 17. The ground electrode tip has a center electrode side facing surface of the ground electrode tip that is fixed to the ground electrode tip such that it protrudes beyond the center electrode side facing surface of the ground electrode. In the step, the photographing direction in which the center electrode and the ground electrode base end overlap each other is viewed from the front so that the center electrode is on the front side and the base end of the ground electrode is on the rear side when viewed from the photographing means. The shooting direction, around the central axis of the center electrode, the shooting direction substantially orthogonal to the front shooting direction is taken as the side shooting direction, and the ground electrode after bending is shot from the side shooting direction, and the chip position information is obtained. In the generation step, a front image in the axial direction of the ground electrode is determined based on a photographed image of the protruding portion of the ground electrode-side chip and a photographed image of the center electrode or a photographed image of the chip fixed to the center electrode. 17. The ground electrode-side tip axial direction eccentricity information relating to the amount of eccentricity of the center axis of the ground electrode-side tip from the center axis of the center electrode or the center axis of the center electrode-side tip is generated. The spark plug inspection method described in Crab. 18. A ground electrode-side chip surface undulation state measuring step of measuring a surface undulation state of the ground electrode-side chip on the center electrode side facing surface prior to the bending of the ground electrode, and the ground electrode After the bending process, the photographing step of photographing an image of the center electrode or the center electrode side tip and the ground electrode, and the surface of the ground electrode side tip facing the center electrode side, the measured Based on the information of the surface undulation state and the information of the photographed image, the opposing surface of the ground electrode-side chip on the center electrode side, the tip surface of the center electrode or the ground electrode of the center electrode-side chip The spark plug inspection method according to any one of claims 1 to 17, further comprising: an inspection information generation step of generating information relating to a distance e from a side facing surface as the inspection information. 19. A chip for determining whether or not a chip fixed to the ground electrode satisfies a desired positional relationship with a predetermined portion of the spark plug based on the inspection information. 19. The spark plug inspection method according to claim 1, further comprising: a position determination step; and a tip position determination result output step of outputting the determination result. 20. When the result of the determination is negative, the tip satisfies the intended positional relationship with respect to the predetermined portion of the spark plug.
20. The spark plug inspection method according to claim 19, further comprising a ground electrode straightening step of straightening the ground electrode. 21. A semiconductor device comprising: a center electrode; a ground electrode disposed so that a tip side faces the center electrode; and a tip fixed to at least one of the center electrode and the ground electrode to form a spark gap. An apparatus for inspecting a spark plug, wherein an image of at least the chip and a portion of the center electrode or the ground electrode to which the chip is fixed (hereinafter, referred to as a chip fixing portion) is obtained. Photographing means for photographing the plug, master image data storing means for storing image data of a master image having a shape corresponding to all or a part of the chip in the photographed image, and matching the master image in the photographed image Chip discriminating means for recognizing a part as a part constituting at least a part of the chip by retrieving the part Generating inspection information on at least one of the size and position of the chip based on at least one of the determined captured image of the chip and the master image positioned so as to be superimposed on the matching portion. A spark plug inspection device, comprising: an inspection information generation unit that performs inspection; and an inspection information output unit that outputs the generated inspection information. 22. A semiconductor device comprising: a center electrode; a ground electrode disposed such that a tip side faces the center electrode; and a tip fixed to at least one of the center electrode and the ground electrode to form a spark gap. An apparatus for inspecting a spark plug, comprising: a photographing means for photographing the ground electrode or a ground electrode-side chip fixed to the ground electrode; and the center electrode or a center electrode-side chip fixed to the center electrode. A chip discriminating means for discriminating an image of the chip and a portion of the center electrode or the ground electrode to which the chip is fixed (hereinafter, referred to as a chip-fixed portion) in the photographed image; The information on the amount of eccentricity between the ground electrode or the ground electrode side tip and the center electrode or the center electrode side tip is generated as inspection information based on A spark plug inspection device, comprising: inspection information generation means; and inspection information output means for outputting the inspection information. 23. The chip discriminating means prepares in advance a master image having a shape corresponding to all or a part of the chip, and searches for a part that matches the master image in the photographed image, thereby obtaining a matching part of the master image. Is determined as a part of at least a part of the chip, the inspection information generating means, the photographed image of the determined chip and the master image positioned so as to be superimposed on the matching portion 23. The spark plug inspection device according to claim 22, wherein inspection information relating to at least one of the size and the position of the chip is generated based on at least one of them. 24. A chip for determining whether or not a chip fixed to the ground electrode satisfies a desired positional relationship with a predetermined portion of the spark plug based on the inspection information. 24. The spark plug inspection device according to claim 21, further comprising: a position determining unit; and a chip position determination result outputting unit that outputs a result of the determination. 25. When the result of the determination is negative, the ground electrode is subjected to a correction process so that the tip satisfies the predetermined positional relationship with the predetermined portion of the spark plug. 25. A ground electrode correcting means.
The spark plug inspection device as described.