JP3479591B2 - Spark plug inspection method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spark plug inspection method and apparatus.

[0002]

2. Description of the Related Art In recent years, in a spark plug used in an internal combustion engine, a noble metal tip fixed to at least one of a ground electrode and a center electrode has been used 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 or the like. When such a positional deviation occurs, for example, the life of the chip is shortened due to uneven wear of the chip,
It leads to troubles such as ignition mistakes.

[0003]

Conventionally, for example, the eccentricity inspection of the spark gap and the dimensional inspection of each portion forming the periphery of the gap are mostly conducted visually, but in this case, the inspection accuracy may vary due to individual differences. There is a problem that defective products are likely to flow out due to inspection omissions. Therefore, in order to automatically perform the eccentricity inspection, a technique of taking an image of the ignition portion of the spark plug with a CCD camera and detecting the amount of eccentricity based on the image is disclosed in, for example, Japanese Patent Laid-Open No. 8-153566. There is.

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

An object of the present invention is 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, which enables accurate and efficient inspection of the tip position, gap eccentricity and the like. To provide an inspection method and device.

[0006]

Means for Solving the Problems and Actions / Effects The first of the methods for inspecting a spark plug according to the present invention is to provide a center electrode, a ground electrode arranged so that its tip side faces the center electrode, and the center electrodes. The present invention relates to a method for inspecting a spark plug including a tip that is fixed to at least one of a ground electrode and forms a spark gap, and includes the following steps in order to solve the above problems. . 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) can be 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 matching portion with the master image is searched for in the photographed image. Determined as a part that forms a part. Inspection information generation step: generates inspection information regarding 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. . Inspection information output step: The generated inspection information is output.

The first of the spark plug inspecting devices of the present invention corresponding to this is a center electrode, a ground electrode arranged so that its tip side faces the center electrode, and the center electrode and the ground electrode. The present invention relates to a spark plug inspection device including a chip fixed to at least one side to form a spark gap, and is characterized by including the following means in order to solve the above problems. Imaging means: An image of the spark plug is taken so that an image of at least the chip and a part of the center electrode or the ground electrode to which the chip is fixed (hereinafter referred to as a chip fixed part) is obtained. Master image data storage means: stores image data of a master image having a shape corresponding to all or part of the chip in the captured image. Chip discriminating means: By discriminating a part of the photographed image that matches the master image, the matching part is discriminated as a part forming 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 determined captured image of the chip and the master image positioned so as to be superposed on the matching portion. To do. Inspection information output means: Outputs the inspection information.

According to the first method or apparatus of the present invention, by searching for a part that matches the master image in the photographed image, the matching part is discriminated as a part forming at least a part of the chip. . As a result, the tip portion can be accurately specified, and in turn, the inspection regarding the tip position, the gap eccentricity, etc. can be performed accurately and efficiently. Further, even when no clear contrast is generated between the chip and the electrode portion, the master image can be used to accurately specify the position of the outline of the chip portion, and the inspection accuracy can be improved.

Next, a second method of inspecting a spark plug according to the present invention comprises: a center electrode; a ground electrode arranged so that its tip end faces the center electrode; and at least one of the center electrode and the ground electrode. The present invention relates to a method for inspecting a spark plug including a tip that is fixed to form a spark gap, and is characterized by including the following steps in order to solve the above problems. Photographing process: photographing of the ground electrode side chip and the center electrode fixed to the ground electrode, photographing of the center electrode side chip and the ground electrode fixed to the center electrode, ground electrode side chip and the center electrode fixed to the ground electrode At least one of photographing with the central electrode side chip fixed to the center electrode and photographing with the central electrode and the central electrode side chip fixed to this is performed. Chip discrimination process: In the captured image, a chip,
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 fixed portion) is determined. Inspection information generation step: information regarding the amount of eccentricity between the ground electrode side chip and the center electrode, information regarding the amount of eccentricity between the ground electrode and the center electrode side chip, and the ground electrode side chip based on the image information after the determination At least one of information regarding the amount of eccentricity between the center electrode side tip and the center electrode side and information regarding 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 inspecting device of the invention corresponding to this is that the center electrode, the ground electrode arranged so that the tip side faces the center electrode, and the center electrode and the ground electrode. The present invention relates to a spark plug inspection device including a chip fixed to at least one side to form a spark gap, and is characterized by including the following means in order to solve the above problems. Imaging means: An 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 is taken. Chip discrimination means: In the captured image, a chip,
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 fixed portion) is determined. Inspection information generating means: Generates information about the eccentricity between the ground electrode or the tip on the side of the ground electrode and the center electrode or the tip on the side of the center electrode as the inspection information based on the image information after the discrimination. Inspection information output means: Outputs the inspection information.

In the second method or device of 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 center electrode or the ground electrode are fixed to the chip. The image of the portion to be fixed (chip fixed portion) is discriminated, and information on the eccentricity between the ground electrode or the tip on the side of the ground electrode and the center electrode or the tip on the side of the center electrode is discriminated based on the image information after the discrimination. 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 eccentricity of the spark gap formed by the tip can be inspected accurately and efficiently.

Also in the above second method and apparatus of the present invention, a master image having a shape corresponding to all or a part of the chip is prepared in advance, and a portion matching the master image in the photographed image is searched for, A matching portion of the captured image with the master image is discriminated as a chip image portion forming at least a part of the chip, and at least one of the discriminated chip image portion and the master image positioned so as to be superposed on the chip image portion. The inspection information regarding the chip size and / or position can be generated based on As a result, the tip portion can be specified more accurately, and in turn, the inspection regarding the tip position, the amount of gap eccentricity, and the like can be performed more accurately.

At the time of chip discrimination, 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, and in the photographed image, between pixels corresponding to the master image. It is possible to select the portion where the total sum of the density differences of 1 is the minimum as the conforming portion. By doing so, the matching accuracy between the captured image and the master image can be improved, and the chip shape can be specified more accurately, and the inspection accuracy can be further improved. In this case, in the above method or apparatus, the density value level of each pixel in the direction intersecting with the chip outline direction changes from one of a state of being larger than the threshold value and a state of being smaller than the threshold value to the other. position,
Or, add a chip contour line information generation step or means for determining the position where the rate of change of the density value level of each pixel detected along the direction intersecting the chip contour line direction is the maximum, as the chip contour line position. You can This allows
The outline position of the chip can be specified with high accuracy.

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

When the chip has a circular axial cross section, in the chip discrimination step, the circular master image is adapted to the photographed image of the axial end face of the chip to obtain the chip outline information. In the generation step, it is possible to determine three different points as the contour line position of the axial end face of the chip, and to determine a circle passing through these three points as the contour line of the axial end face. Thereby, the outline of the axial end surface of the circular chip can be easily determined.
The circle can be specified by defining its center position and radius.

In this case, a plurality of sets of three different points are determined, the center positions and radii of a plurality of circles passing through each of the three points are determined, and the final outline of the axial end face of the chip is determined by the plurality of sets. By defining the average center position of the circle and the average radius as the circle 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 a welded portion is formed around the tip and the outline is slightly obscured, this can be 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. However, for example, when it is desired to inspect the gap eccentricity, the mounting position of the chip, etc., the chip position reference is used. It is more desirable to appropriately select a predetermined component portion (position reference component portion) of the spark plug that provides the information, and obtain the information that gives the relative positional relationship between the position reference component portion and the chip as the inspection information. In this case, the above-described method or apparatus is based on the photographing step or means for photographing the image of the position reference constituent portion together with the chip, the photographed image of the chip, and the photographed image of the position reference constituent portion. The chip position information generating step or chip position information generating means for generating the positional relationship information for the portion is included.

A master image having a shape corresponding to all or a part of the position reference constituent portion is prepared in advance, and a matching portion of the photographed image with the master image is a position reference constituent portion forming at least a part of the position reference constituent portion. The position reference constituent part is determined based on at least one of the position reference constituent image part and the master image positioned so as to be superimposed on the position reference constituent part image part. Can be specified. In this case, the captured image and the master image are formed by combining the output states of a plurality of pixels capable of outputting the intermediate density, and the total of the density differences between the pixels corresponding to the master image in the captured image is formed. It is possible to select the part with the minimum value as the matching part. Also, a position where the density value level of each pixel changes from one of a state where the density value level is larger than the threshold value and a state where the density value is smaller than the threshold value to the other in a direction crossing the outline of the position reference constituent part, or a position The position where the rate of change of the density value level of each pixel detected along the direction intersecting the outline line direction of the reference component part is maximum can be determined as the outline line position of the position reference component part. This makes it possible to specify the contour line position of the position reference constituent portion with extremely high accuracy.

The outline direction of the position reference component is
Similar to 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 previously photographing a chip or a position reference constituent part of the same type as that used for the spark plug to be inspected under a predetermined condition.

The shape of the spark plug to be inspected is not particularly limited, but the following may be possible, for example. That is, the ground electrode has a shape in which the tip end side is bent back inward by bending so that the base end side is coupled to the metal shell while the tip end side surface faces the tip end surface of the center electrode. To do. The ground electrode side tip is fixed to the tip side surface and faces the center electrode tip surface or the center electrode side tip fixed to the tip surface. In this case, at least one of the following information is obtained in the chip position information generating step. Information related to the distance a between the central axis of the ground electrode tip and the center of the ground electrode side tip (the position reference constituent portion is the tip of the ground electrode). Here, the center point of the ground electrode side chip means the geometrical center of gravity position of the photographed image of the ground electrode side chip (the same applies hereinafter). .Tip fixed to the ground electrode (ground electrode side chip)
Information 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 portion of the ground electrode). Information related to the facing distance e between the front end surface of the center electrode or the facing surface of the center electrode side chip on the ground electrode side and the facing surface of the ground electrode side chip on the center electrode side (so-called spark gap interval: position reference The component is the center electrode or the center electrode side tip). As a result, it is possible to accurately obtain information that reflects the positional deviation state or the eccentricity state of the ground electrode side tip.

Further, in the inspection information generating step or means, at least one of the following information may be generated based on the photographed image of the ground electrode and the photographed image of the center electrode. Information related to the distance c between the central axis of the tip of the ground electrode and the central axis of the central electrode or the central axis of the central electrode side tip. Information related to the distance d between the tip surface of the ground electrode and the central axis of the central electrode or the central axis of the central electrode side tip. By obtaining these pieces of information together, the gap forming state of the spark plug can be inspected more accurately.

Depending on the shooting direction of the shooting means, it may be difficult to obtain information on the relative position between the position reference component and the chip. In this case, the spark plug is photographed from two or more directions different from each other, and the positional relationship information is generated from the photographed images of the chip and the photographed images of the position reference constituent portion from the plural directions.
For example, when the center electrode is on the front side and the ground electrode is on the rear side when viewed from the imaging means, the center electrode and the ground electrode base end are seen to overlap each other. If the side-by-side shooting direction is a shooting direction that is substantially orthogonal to the front-side shooting direction around the center axis of the, the information related to the distance c should be generated from the shot image in the front-side shooting direction. Also, information related to the distance e,
The information related to the distance d is preferably generated based on the captured image in the lateral shooting direction.

On the other hand, depending on the type of spark plug,
Most of the tips on the ground electrode side are buried in the ground electrode side, and even if there is a protruding portion, it is difficult to identify the outer shape of the tip protruding portion due to a welding droop portion or the like. In this case, after bending the ground electrode,
Shooting the chip can be difficult. Therefore, before the bending process is performed on the ground electrode, the spark plug is photographed in the front photographing direction to obtain an image of the side surface of the ground electrode and the ground electrode side chip fixed to the side surface. If the pre-imaging step is performed (by the pre-bending imaging means), the positional relationship between the ground electrode and the ground electrode side tip can be accurately grasped based on the captured 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, from the center axis of the center electrode of the ground electrode side chip in the ground electrode width direction or the center axis of the center electrode side chip. The width direction eccentricity information generation step of obtaining information regarding the eccentricity amount (information on the ground electrode side chip width direction eccentricity amount) can be performed. Also,
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 based on the information related to the distance b and the information related to the distance d. It is also possible to carry out the axial eccentricity information generation step of generating information (ground electrode side tip axial eccentricity amount information) regarding the above. As a result, even if it is difficult to specify the tip position on the ground electrode from the image captured from the frontal or lateral imaging direction, such as when the chip is buried in the ground electrode, for example, by performing the imaging process. By obtaining the information related to the distances a and b, it is possible to accurately grasp the eccentricity amount in each of the directions.

On the other hand, in the case of a spark plug in which the facing surface of the tip on the side of the center electrode is fixed to the tip of the ground electrode so as to protrude from the facing surface of the ground electrode on the side of the center electrode, for example, after bending The ground electrode is photographed from the front photographing direction described above, and the width of the ground electrode is determined based on the photographed image of the protruding portion of the ground electrode side tip and the photographed image of the center electrode or the tip fixed to the center electrode. Information about the amount of eccentricity of the center axis of the ground electrode side chip in the direction from the center axis of the center electrode or the center axis of the center electrode side chip (ground electrode side chip width direction eccentricity amount information) may be generated. In addition, the ground electrode after bending is photographed from the lateral photographing direction described above, 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 taken. Based on this, information about the amount of eccentricity of the center axis of the ground electrode side tip in the direction of the ground electrode side from the center axis of the center electrode or the center axis of the center electrode side tip (ground electrode side tip axis direction eccentricity information)
May be generated. However, in this case as well, the distance a is determined based on the captured image obtained in the pre-bending capturing step.
Alternatively, information relating to the distance b may be obtained, and the information on the eccentricity described above may be obtained using the values of a or b.

On the other hand, when many parts of the ground electrode side chip are buried in the ground electrode, the distance e (spark gap interval) may not be accurately determined only by the information of the photographed image. In this case, in the method (or apparatus) of the present invention, the ground electrode side chip surface undulation state measuring step of measuring the surface undulation state of the facing surface of the center electrode side of the ground electrode side chip prior to 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 tip on the center electrode side and the ground electrode is photographed after bending the ground electrode. In addition, the inspection information generating step (or means) is performed on the ground electrode side based on the information of the measured surface undulation state of the facing surface of the ground electrode side chip on the center electrode side and the information of the captured image. Information relating to the distance e between the facing surface of the chip on the side of the center electrode and the facing surface of the center electrode or the facing surface of the chip on the side of the center electrode on the side of the ground electrode is generated as inspection information.

According to this, the surface undulation state (for example, information of surface roughness or surface displacement distribution) of the opposing surface of the ground electrode side chip on the side of the center electrode before bending the ground electrode.
Even if the ground electrode side tip is buried in the ground electrode, the distance e is measured 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. You will be able to easily obtain information related to. As the means for measuring the surface undulation state, a 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 used. Various known methods such as a method of reflecting on the measurement surface and measuring based on the information of the reflected light can be adopted.

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

[0030]

1 and 2 show a spark plug inspection device of the present invention (hereinafter simply referred to as an inspection device).
FIG. 3 is a plan view and a side sectional view conceptually showing one embodiment of FIG. That is, the inspection apparatus 1 uses the spark plug to be processed (hereinafter, also referred to as a work) W on the circumferential path (conveyance path) C.
A rotary conveyer 2 as a conveying unit that intermittently conveys the workpiece W along a circumferential path C, and a workpiece carry-in mechanism 11 as a spark plug carry-in mechanism to be processed and a ground electrode of the workpiece W at predetermined positions. A workpiece positioning mechanism (I) 12 for positioning, an imaging / analysis unit (I) 13 (imaging means before bending), a rejected product discharging mechanism (I) 14, a ground electrode bending machine 15, and a workpiece 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 an imaging / analysis unit (I
II) 20, rejected product discharging mechanism (III) 21, and product discharging mechanism 22 are arranged in this order. The positions where the respective mechanisms and the units 11 to 22 are arranged are the positions where the respective steps of the inspection of the work W are performed. The distance between each of these mechanisms and units is adjusted so that an angle θ along the circumferential path C is a unit and is an integral multiple of the angle θ.

As shown in FIG. 1 (b), the rotary conveyor 2 has a disk-shaped carrier rotating body 30 arranged substantially horizontally.
And a plurality of work holding portions 23 that detachably hold the spark plug W to be processed fixed to the work holder H in a substantially horizontal manner, are integrated along the circumferential path C at intervals corresponding to the angle θ. Has been formed. Then, the transport rotating body 30 is intermittently driven to rotate by the servo motor 34 as an intermittent drive unit in units of the angle θ via a rotation transmission mechanism (not shown). As a result, the work W held by each work holding portion 23 is intermittently conveyed on the circumferential path C shown in FIG. 1 while being sequentially stopped at the process execution position by each mechanism and the units 11 to 22. Becomes

As shown in FIG. 2, the work carrying-in mechanism 11, the rejected product discharging mechanism (I) 14, the same (II) 18, the same as shown in FIG.
(III) 21 and the product discharge mechanism 22 are, for example, by a transfer mechanism that transfers 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. Composed. The transfer mechanism 35 includes a chuck hand mechanism 36 that is held by an air cylinder 37 so as to be able to move up and down, an advancing / retreating drive mechanism 39 that drives the chuck hand mechanism 36 in the radial direction of the circumferential path C by an air cylinder 38, and the like. 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 rising, it is driven back and forth by the air cylinder 38 to move to the transfer destination, and then descends again to move to the work holder H.
The holding of the (workpiece W) is released and the transfer is completed.

Next, returning to FIG. 1, the photographing / analyzing unit
(I) 13, the same (II) 17, and the same (III) 20 all have the same structure. Hereinafter, the imaging / analysis unit (I) 13 will be representatively described with reference to the schematic diagram of FIG. That is, the image capturing / analyzing unit (I) 13 includes a ring light 238 as an illumination unit that illuminates the front end of the work W, a filter (for example, a polarizing filter) 239, and an image capturing camera 40 as an image capturing unit, each of which includes a frame (not shown) or the like. It is held at a predetermined height. Here, the ring light 238,
The filter 239 and the photographing camera 40 are 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 constructed as a CCD camera having a two-dimensional CCD sensor as an image detecting section, and the center electrode W2 of the work W held horizontally is provided.
, The ground electrode W1, and their center electrode W2 and ground electrode W1
The spark gap g (FIG. 4) formed between the and is photographed from above. Note that each of the image capturing / analyzing units 13, 17, 20 captures a reference body of known dimensions 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 photographing camera 40 is adjusted. It should be noted that the image magnifications may be the same among the photographing / analyzing units 13, 17, 20 or may be different between two or more. Further, it is desirable that the photographing optical system of each photographing camera 40 is configured by a telecentric optical system so that a change in image size due to a focus shift is small.

Next, in the spark plug W to be processed used in this embodiment, as shown in FIG. 4B, for example, the base end side of the ground electrode W1 is connected to the metal shell W3, while the ground electrode W1 The tip side is bent inward by bending so that the side surface on the tip side faces the tip surface of the center electrode W2. A ground electrode side tip W4 is fixed to the side surface on the tip side 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 Ni alloy, for example, and the tip W4 is made of Pt or I.
Mainly composed of precious metals such as r.

The spark plug W to be processed is, as shown in FIG. 4, at the time of being loaded by the work loading mechanism 11 (FIG. 1).
As shown in (a), the ground electrode W1 is in a state before being bent. Further, the spark plug W to be processed is 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 with respect to the work holder H when viewed from the photographing camera 40 (FIG. 3). And the base end of the ground electrode W1 are attached so as to be seen to overlap each other (that is, the positional relationship in which the imaging direction is the front imaging direction). The ground electrode W1 is bent by the ground electrode bending machine 15 (FIG. 1) to be in the state shown in FIG. 4 (b). Further, the work 90 ° turning mechanism 19 further turns 90 ° around the axis of the center electrode W2, as shown in FIG.
The state shown in (c), that is, the state in which the shooting direction is the side shooting direction substantially orthogonal to the front shooting direction is maintained. It should be noted that, by turning 90 ° in the opposite direction,
The state of (d) may be used.

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

FIG. 6 shows photographing / analyzing units 13, 17,
FIG. 20 is a block diagram showing an electrical configuration example of 20 (hereinafter, the imaging / analysis unit 13 will be representatively described). photograph·
The control unit 110 of the analysis unit 13 includes an I / O port 111, a CPU 112 and a ROM 11 connected to the I / O port 111.
3 and a RAM 114, etc., and a ROM 113 stores an image analysis program 113a. Also, I / O port 11
1, a photographing camera 40 (two-dimensional CC
D sensor 115 and sensor controller 116 for converting the sensor output to a two-dimensional digital image input signal
And a storage device 115 as a master image data storage unit are connected. The storage device 115 stores master image data 115a and size data 115b that gives reference values for each inspection size described later. In addition, the RAM 114 stores a work area 114a of the CPU 112, photographed image data of the work W by the photographing camera 40, master image data used for inspection of the work W, and size data.
b to 114d are formed. The CPU 112
Is a main component of the chip discriminating unit, the inspection information generating unit, the chip position discriminating unit, and the chip position discriminating result outputting unit by the image analysis program 113a. The master image data may be stored in the storage device 105 connected to the main control unit 100 of FIG. 5, and necessary data may be transferred to the photographing / analyzing units 13, 17 and 20 for use.

The operation of the inspection apparatus 1 will be described below with reference to the flowchart. FIG. 7 shows a flow of each step of the inspection when focusing on one work W. However, in this embodiment, as shown in FIG.
While being intermittently conveyed, each inspection process receives each instruction from the main control unit 100 in FIG.
22 are executed in parallel. Therefore, the steps in the flowchart of FIG. 7 are not always 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 capturing / analyzing unit (I) 13 captures the image of FIG. 4A (FIG. 7: S1, S2). Then, the image processing / dimension inspection 1 is performed in S3 of FIG.

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

The master image is created, for example, by previously photographing a spark plug constituent portion to be inspected under a predetermined condition. For example, as shown in FIG. 17, in the case of a rectangular photographed image 51 such as a ground electrode, a master image 50 corresponding to each corner is prepared, and the outlines of the components used for dimension measurement are selected from them. Make sure to select and use the ones necessary for the decision. Here, each of the master image 50 and the captured image 51 is formed as a so-called gray scale image by combining the output states of a plurality of pixels capable of outputting an intermediate density.

The master image 50 is searched for a matching position with the photographed image 51 while moving in parallel between respective positions on the pixel plane of the photographed image 51. That is, in FIG.
As shown in (a), a density difference (or its absolute value) between corresponding pixels is calculated between the master image 50 positioned at a predetermined position on the pixel plane and the captured image 51 overlapping with the master image 50. , Calculate the total (or average). Then, the photographed image portion having the smallest total value calculated for each position is selected as the matching portion (FIG. 9:
S104 to S107). For example, when the object to be photographed is a chip, this matching part is the chip image part. Also, S
In 108, the master image 50 is positioned in a state of being overlapped with the conforming portion, its 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 set. It is a confirmation process.

FIG. 10 shows the flow of edge position determination processing. First, a temporary edge position is determined on the outline of the master image 50, a pixel matrix 60 having a constant size as shown in FIG. 18A is defined, and then FIG.
As shown in, the density value of each pixel is read (FIG. 10: S
151, S152). Then, the density values of the pixels are summed up for each row, with the direction parallel to the temporary contour line as the row direction (corresponding to the contour line direction in the claims) and the direction at right angles as the column direction (S153: density after that). The sum of the values is called the density value level). Next, the process proceeds to S154 and S155 of FIG. 10, and the position where the rate of change of the density value level gi of each pixel P in the column direction is the maximum is determined as the edge position. That is, as shown in FIG. 18C, the difference between the column-direction adjacent values of gi is calculated, and the position where the difference is maximum is set as the edge position. Note that a certain threshold value may be set for the density value level gi, and a row-direction pixel position 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 an edge position with the threshold value sandwiched therebetween.

Returning to FIG. 8, as the outline of the ground electrode W1, both widthwise edges E1 and E2 of the ground electrode W1 and the tip edge E3 are formed.
(FIG. 19) is determined by the above method. In this case, at least two points on the outline defined by the edge position determination process are required to determine each outline, but three points or more are used to improve accuracy, and linear regression is applied to this. You may Then, when each contour line is determined, the coordinates of the intersection position can be calculated. In this processing, the coordinates of both end points T1 and T2 of the leading edge E3 are calculated, and further the coordinates (xt, yt) of these midpoints T3 are calculated (above, S52, S53).

Subsequently, in S54 of FIG. 8, the outline of the axial end surface of the ground electrode side tip W4 is similarly recognized. In this case, as shown in FIG. 20 (a), the master image 50 is matched with the captured image of the ground electrode side tip W4,
As shown in (b), three points on the outline are determined by the same edge determination process as described above, and the 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 calculated (FIG. 8: S55). Then, as shown in FIG.
The center OO, that is, the distance a between the central axis O2 of the ground electrode side tip W4 and the central axis O1 of the ground electrode W1 is a =
Calculated by xt-x0. Further, the distance b from the tip edge (tip surface) E3 of the central axis of the ground electrode side tip W4 is represented by b =
It is determined by yt-y0 (S56).

In order to more accurately determine the outline of the axial end surface of the ground electrode side tip W4, a plurality of sets of three different points on the outline are determined and a plurality of circles passing through each of the three points are determined. The center position and radius of each of the circles, and the final outline of the axial end surface of W4 is defined as a circle whose center and radius are the average center position of these circles and the average radius. It is desirable to set. The processing in this case will be described based on the process explanatory diagram of FIG. 32 and the flowchart of FIG. 33.

First, in S301 of FIG. 33, an image of the outline of the axial end surface of the ground electrode side tip W4 is photographed,
Next, in S302, as shown in FIG. 32A, the master image 50 is adapted to this, and the temporary center Ov of the chip outline is determined. Here, if the total value 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, the defect determination that the ground electrode side chip W4 is absent is performed.

On the other hand, if K is less than or equal to K0, the process proceeds to S305, and as shown in FIG. 32 (b), a predetermined angular interval γ is obtained by the above-mentioned edge position fixing process centered on the temporary center Ov.
The contour line points (edge positions) E C are determined (for example, at intervals of 2 °) (S305). Then, as shown in FIG. 32 (c), each contour line point EC is used as a reference point (indicated by a circle in the figure),
It is selected as an outline line point (indicated by Δ in the figure) at a position that is deviated to the left and right of the reference point by an angle β (for example, 44 °), and passes through the selected two points and the reference point, a total of three points. The center O'of the circle and the radius r'are calculated (S307). If the determined r ′ is out of the standard range (for example, the lower limit value rmin and the upper limit value rmax) of the chip in S308, it is considered to be defective, and the defective circle counter Np is incremented by 1 (S309), and in S310. The count value of the defective circle counter Np and the reference value N0 (for example, 30) are compared and judged.

If the defective circle count value Np exceeds the reference value N0 in S310, the process proceeds to S313 and a defect determination that the ground electrode side chip W4 is absent is performed. On the other hand, if the count value of the defective circle counter Np is less than or equal to the reference value N0, the process proceeds to S311, and the center O'and radius r'of the three-point circle are calculated for all outline points EC. In this manner, when the center O ′ and the radius r ′ of the three-point circle are calculated for all the contour line points EC in S311, S31 is performed.
4, the calculated center coordinates O'i (= (x
i, yi), i = 1, 2, ..., N) and 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 end face in the axial direction of the ground electrode side tip W4, and the process is completed.

Next, returning to FIG. 8, the inspection determination 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 to b, that is, | a | + α or | b | + α falls within the specified range. If yes, pass, otherwise fail. The data in the specified range is read out from the dimension data 115b in FIG. 6 and used.

In the above processing, the photographing / analyzing unit (I) 13 includes a photographing camera 40 as a photographing means,
A storage device 115 as a master image data storage means,
The CPU 112 is provided as a chip discriminating means, an inspection information generating means, and an inspection information outputting means, and finally, a value of a or b is generated as the 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 above inspection result is unacceptable, an unacceptable notification is displayed on, for example, the monitor 107 connected to the I / O port 101 in FIG.
(I) The work W that has failed in 14 (FIG. 1) is discharged, and after the work W is confirmed to be taken out, the post-processing ends (S4 → S15 to S17: discharge of a product that fails this routine. Called a routine). On the other hand, if it passes, the process proceeds to S5 and thereafter, and the ground electrode bending machine 15 of FIG.
Is bent (S5), and the work positioning mechanism
After the work W is repositioned by the (II) 16 (S6), the image capturing / analyzing unit (II) 17 captures the image of FIG. 4B (S7). Then, in S8 of FIG. 7, the image processing / dimension inspection 2 is performed.

FIG. 11 shows the flow of the image processing / dimension inspection 2. This processing is also basically performed based on a combination of the matching processing with the master image and the edge position determination processing by the edge tool (hereinafter, referred to as gray search processing) 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 from the front and the edge E6 facing the center electrode W2 are determined, and the coordinates of both end points T4 and T5 of E6 are obtained by the intersections thereof, and the middle point of E6 is further determined. Coordinates of T6 (x
k, yk). Also, both edges E7, E8 of the center electrode W2
And the leading edge E9 are determined, and the coordinates of the end points T7 and T8 of E9 are obtained from their intersections, and the coordinates (xl, yl) of the midpoint T9 of E9 are obtained. Then, the distance c between the central axis of the ground electrode W1 and the central axis O3 of the central electrode W2 is c = x
Determined by k-xl (above, FIG. 11: S201 to S20
7).

The tip edge (tip surface) E9 of the center electrode W2
And the facing distance e between the facing surface of the ground electrode side chip W4
(Spark gap interval) in a predetermined direction (eg ground electrode W
It may be determined as the minimum value of the distance between the tip edge (tip surface) E9 of the center electrode W2 and the facing edge E6 of the ground electrode W1 in the direction substantially parallel to both end edges E4 to E5 of 1. (S208). Then, the inspection determination is made in S209. That is, if | c | + α (or | e | + α) is within the specified range, the result is acceptable, and if not, it is not acceptable (FIG. 15A: J51 to J53).

Returning to FIG. 7, in S9, the rejected product is S
As in the case of 4, the rejected product discharging routine of S15 to S17 is performed (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 turning mechanism 19 turns the work position 90 degrees, and
4 (c) (or FIG. 4) by the analysis unit (III) 20.
The image of (d) is photographed (S11). And S12
Then, the image processing / dimension inspection 3 is performed.

FIG. 12 shows the flow of the image processing / dimension inspection 3. This processing is also executed based on a combination of the matching processing with the master image and the edge position confirmation processing by the edge tool. The outline will be described with reference to FIG. That is, the ground electrode W1 photographed laterally
The leading edge E10 of E.sub.10 and the edge E11 facing the center electrode W2 are determined, and the coordinates (x
5, y5) is calculated. Also, both edges E12, E1 of the center electrode W2
3 and the leading edge E14 are determined, the coordinates of the end points T11 and T12 of E14 are obtained from the intersections thereof, and the midpoint T13 of E14 is determined.
The coordinates (xm, ym) are calculated. Further, the facing distance e (spark gap interval) between the tip edge (tip surface) E14 of the center electrode W2 and the facing surface of the ground electrode side tip W4 is set to a predetermined direction (for example, approximately equal to the tip edge E10 of the ground electrode W1). Parallel direction)
Is determined as the minimum value of the distance between the tip edge (tip surface) E14 of the center electrode W2 and the facing edge E11 of the ground electrode W1. Further, the distance d between the tip edge (tip surface) E10 of the ground electrode W1 and the central axis O3 of the central 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 by f = x5-xm-b. (S258). Then, the inspection determination is made in S259. That is, | d | + α, | e | + α (or |
If f | + α) is within the specified range, it is acceptable, and if it is not, it is unacceptable (FIG. 16A: J101 to J10).
4).

Returning to FIG. 7, in S13, the rejected product is sent to the rejected product discharge routine of S15 to S17 similarly to S4 (the discharge is the rejected product discharge mechanism (III) 21 of FIG. 1).
Will do). On the other hand, if the result is acceptable, the process proceeds to S14, a notice of acceptance is given, and the product is ejected by the product ejection mechanism 22 of FIG. The work holding portion 23 of the work W is returned to the work carry-in 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 products were only discharged by the rejected product discharge mechanism. For example, for the work W in which the values of c to d do not satisfy the specified range, It is also possible to correct the ground electrode W1 so that it falls within the specified range. When performing the correction, as shown in FIGS. 1 and 5, a correction mechanism (I) 60 (ground electrode correction means) for correcting the widthwise position of the ground electrode W1 and the axial position of the ground electrode W1 are also used. At least one of the correction mechanism (II) 61 (grounding electrode correction means) for correcting the above can be provided.

FIG. 23 conceptually shows a structural example of the correction mechanism (I) 60. That is, the correction mechanism (I) 60 includes the first grip portion 71 that grips and fixes the base end portion of the ground electrode W1.
And a second grip 70 that also grips the tip side. Then, with the base end side gripped by the first grip portion 71, the tip end side of the ground electrode W1 is set to be substantially parallel to the central axis of the center electrode W2 by the twist drive portion 72 via the second grip portion 70. By applying a twisting force around the twisting axis, the widthwise position of the ground electrode W1 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 has a work holding portion 73 that holds the work W so that the center electrode W2 does not move.
A tip gripping portion 74 that is slidable in the axial direction of the ground electrode W1 by a guide 75 and that grips the tip end portion of the ground electrode W1; and a base end gripping portion 76 that grips the base end portion of the ground electrode W1. Have. Then, in a state in which the tip is gripped by the tip gripping portion 74, a predetermined axis (perpendicular to the plane of the drawing) orthogonal to the axis O4 of the ground electrode W1 and the axis O5 of the center electrode W2 is provided by the twist driving section 77 via the base end gripping section 76. The axial position of the ground electrode W1 is corrected by applying a twisting force to the ground electrode W1 of the work W held by the work holding portion 73 around the orthogonal axes.

The processing flow in this case is as shown in FIG. 13, for example. That is, the processes of S1 to S16 are almost the same as those of FIG. 7, but it is determined whether or not the values of c to d can be corrected for the work W which is determined to be rejected in S9 to S15 (S22. , S2
4) If the correction is possible, the correction process is performed (S21, S2).
3). Alternatively, the correction process may be directly performed without performing the correction determination. In either case, in the image processing / dimension inspection 2 to image processing / dimension inspection 3 of FIGS. 11 and 12, steps S210 to S260 of correction value calculation are performed.
Is added. An example of the processing is shown in FIG.
As shown in FIG. 6 (b), the detected values of c to d are compared with the respective prescribed ranges, and if the correction is impossible, it is judged as a failure. If the correction is possible, the detected c or d is detected. The correction mechanism (I) 60 or the correction mechanism (II) is set so that the deviation between the value of d and the specified value is reduced to fall within the specified range.
The correction value to be instructed to 61 is calculated and set.

Here, the correction mechanism (I) 60 or the correction mechanism
After the straightening process according to (II) 61, the inspection can be performed again to confirm whether 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 reveals that the value of c to d does not satisfy the specified range, the work W is discharged as a rejected product, or the second stage correction is performed. You can When performing the second-stage straightening, a new straightening mechanism is added or the work is returned to the upstream straightening mechanism manually or the like so that the straightening is performed again.

In the above processing, each value of a to e is individually inspected and the pass / fail judgment is made as to whether each value is within the specified range. Based on the above information, the 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 about the distance b and the information about 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. You may

FIG. 25 shows an example of processing in this case. That is, although the processes of S1 to S14 are almost the same as those of FIG. 7, the values of a to c are measured in the image processing / dimension inspection 1 and 2, but the inspection determination for each of these values (see FIG. 8). : S57, FIG. 11: S209) are omitted. Instead, the inspection determination processing S259 in the image processing / dimension inspection 3 of FIG. 12 is as shown in FIG. That is, the width direction eccentricity amount is a by the measured values of a to d.
+ C and the axial eccentricity amount are calculated by b-d, respectively (J151 to J153). The value of e is used as it is. Then, | a + c | + α and | b−d
If each value of | + α and | e | + α is within the specified range, it is judged as pass, and if it is out of the specified range, it is judged as fail (J154 to J1).
58). If | a + c | + α is not within the specified range, the correction mechanism (I) 60
Thus, the widthwise correction of the ground electrode W1 may be performed. If | b−d | + α is not within the specified range, the correction mechanism (II) 61 may correct the ground electrode W1 in the axial direction so that it falls within the specified range.

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

As shown in FIG. 28, the center electrode W2
There is a case where the center electrode side tip W5 is fixed to the tip surface of the. In this case, the value of c'or the value of d is
It is measured with reference to the center axis of the center electrode side tip W5, not the center axis of the center electrode W2. For example, the above c '
The value of is the tip edge E32 (tip surface,
Alternatively, the midpoint coordinate of the facing surface on the side of the ground electrode is T32 (x
l, yl) and c '= xp-xl. Further, based on the image of the center electrode W2 and the image of the center electrode side tip W5, the distance between the center axes of the two (that is, the amount of eccentricity) may be calculated as the inspection information. In this case, this eccentricity is, for example, as shown in FIG. 29 (a), the eccentricity δ1 in the width direction of the ground electrode W4, or, as shown in FIG. 29 (b), the eccentricity of the ground electrode W4 in the axial direction. It can be calculated as the amount Δ2.
When the center electrode side tip W5 is provided, the ground electrode side tip W4 may not be provided in particular.

On the other hand, as shown in FIG. 22, when many parts of the ground electrode side chip W4 are buried in the ground electrode W1, the above-mentioned distance e (spark gap interval) can be obtained only by the information of the photographed image. In some cases, it cannot be accurately determined. In particular, when the ground electrode side tip W4 is fixed by laser welding, the tip surface is likely to be roughened, and the measurement of e becomes more difficult. In this case, before the bending of the ground electrode W1, the surface undulation state of the facing surface of the ground electrode side tip W4 on the side of the center electrode W2 is measured by the surface undulation state measuring device 200 shown in FIG. Taken 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 relief information.

As the surface undulation state measuring device 200, for example, as shown in FIG. 30A, the probe 201 is brought into contact with the surface to be measured Si of the ground electrode side tip W4, and the probe 201 is kept in this state. The probe 2 when moved on Si
A method of reading the displacement of 01, or a method of reflecting the laser light L from the light source 202 on the surface Si to be measured, receiving the reflected light by an optical sensor 203 such as a CCD sensor, and measuring based on the detection information. Various known devices can be adopted. For example, when the laser light L is emitted 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 undulation state of the surface to be measured Si. Because it changes
The displacement of each position on the measured surface Si can be read from the information.

In this case, the facing edge Ek of the ground electrode W1 is determined by the gray search method described above, and as shown in FIG.
It is possible to measure the undulation amount h ′ at each position on the measured surface Si with the facing edge Ek as a reference. Then, after bending the ground electrode W1, the corresponding undulation amount from the distance d0 at each position between the facing edge (opposing surface) Ej of the center electrode W2 and the facing edge Ek (or extension thereof) of the ground electrode W1. h '
If the value of is reduced, the distance between the facing surfaces of the ground electrode side tip W4 and the center electrode W2 at that position can be calculated as d0-h '. Then, for example, the minimum value of this d0-h 'may be determined as the above e. Even when the center electrode side chip W5 is provided, the same method is used for e
Can be determined.

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

In the above embodiment, the photographing / analyzing unit (I) 13, the photographing unit (II) 17, and the photographing unit (III) 20 photograph the spark plug constituting portion to be inspected as a gray scale image. , If there is a sufficient contrast between the portion to be inspected and the background portion (or the adjacent portion), the gray search processing described above is not performed, and the image is binarized to perform a simpler processing. May be.
For example, as shown in FIG. 4 (c) or (d), when the spark plug (work) W is photographed from the side, there is another component behind each outline of the component used for the inspection. Since it does not exist and it is a space, the image capturing / analyzing unit (III) 20 (FIG. 1 etc.) for capturing it can be configured to perform the binarization processing as described above. in this case,
By illuminating the work W with a backlight from behind to make the image a silhouette, a clearer contrast can be obtained, which is convenient for the binarization processing.

[Brief description of drawings]

FIG. 1 is a plan view and a side sectional view schematically showing an embodiment of a spark plug inspection device of 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 diagram 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 the electrical configuration of the imaging / analysis unit.

FIG. 7 is a flowchart showing the 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 showing the flow of image recognition processing.

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

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

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

FIG. 13 is a flowchart showing the flow of an inspection process when correcting the 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 the flow of an inspection determination routine and a correction value calculation routine of the image processing / dimension inspection 3.

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

FIG. 18 is an explanatory diagram showing the concept of edge confirmation 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 of determining the outline of the ground electrode side chip.

FIG. 21 is an explanatory diagram 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 of the same.

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

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

FIG. 27 is an explanatory diagram showing contents of a modified example of image processing of image processing / dimension inspection 2.

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

FIG. 29 is an explanatory diagram for 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 for inspecting the amount of spark gap when the surface undulation of the ground electrode tip is 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 of determining the outline of the ground electrode side chip.

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

[Explanation 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 side tip W5 Center electrode side tip 13 Imaging / analysis unit (I) (imaging means, spark plug inspection device) 17 Imaging / analysis Unit (II) (imaging means) 20 Imaging / analyzing 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)

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-8-45645 (JP, A) JP-A-8-306468 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01T 21/02 G01M 19/02

Claims (25)

(57) [Claims] 1. A center electrode, a ground electrode arranged so that a tip side thereof 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 the spark is provided so that an image of at least the tip and a portion of the center electrode or the ground electrode to which the tip is fixed (hereinafter referred to as a tip fixed portion) is obtained. A photographing step of photographing the plug, and in the photographed image, a master image having a shape corresponding to all or part of the chip is prepared in advance, and a portion matching the master image in the photographed image is searched, A chip discrimination step of discriminating the matching portion as a portion forming at least a part of the chip; An inspection information generating step of generating inspection information relating to at least one of a size and a position of the chip based on at least one of the master image positioned so as to be superposed on the matching portion, and the generated inspection information. A spark plug inspection method comprising: an inspection information output step for outputting. 2. A center electrode, a ground electrode arranged so that its 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, 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; and the ground electrode A photographing step of photographing at least one of the ground electrode side chip fixed to the center electrode and the center electrode side chip fixed to the center electrode, and the center electrode and the center electrode side chip fixed to the center electrode. , In the captured image, the image of the chip and the part of the center electrode or the ground electrode to which the chip is fixed (hereinafter referred to as the chip fixed part) is discriminated. Information regarding the amount of eccentricity between the ground electrode side tip and the center electrode, and information regarding the amount of eccentricity between the ground electrode and the center electrode side tip, based on the tip discrimination step and the image information after the discrimination. An inspection for generating at least one of information regarding an eccentricity between the ground electrode side tip and the center electrode side tip and information regarding an eccentricity amount between the center electrode side tip and the center electrode as inspection 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 determination step, a master image having a shape corresponding to all or part of the chip is prepared in advance, and a portion of the captured image that matches the master image is searched for to obtain the captured image. A matching portion of the image with the master image is discriminated as a chip image portion forming at least a part of the chip, and in the inspection information generating step, the discriminated chip image portion and the chip image portion are overlapped with each other. The spark plug inspection method according to claim 2, wherein inspection information relating to at least one of a size and a position of the chip is generated based on at least one of the master image positioned by the above. 4. The captured image and the master image are
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 a total density difference between pixels corresponding to the master image is minimum is the matching portion. The spark plug inspection method according to claim 1 or 3, including the chip determination step selected as. 5. A position at which the density value level of each pixel changes from one of a state of being larger than a threshold value and a state of being smaller than the threshold value to the other in a direction crossing the chip outline direction, or a 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 detected along the direction intersecting the outline line direction is the maximum is the outline line position of the chip. 5. The spark plug inspection method according to claim 4, including a chip outline information generation step of determining as. 6. The chip has a circular axial cross section, and in the chip determination step, the circular master image is adapted to a captured image of an axial end face of the chip, 6. The spark according to claim 5, wherein in the contour line information generating step, three different points as contour line positions of the axial end face of the chip are determined, and a circle passing through these three points is determined as the contour line of the axial end face. Plug inspection method. 7. A plurality of sets of three different points 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 contour line of an axial end surface of the chip is defined by:
The spark plug inspection method according to claim 6, wherein an average center position and an average radius of the plurality of circles are defined as circles having a center and a radius, respectively. 8. In order to inspect a positional relationship between the tip and a predetermined constituent portion of the spark plug (hereinafter, referred to as a position reference constituent portion) that provides a position reference for the tip, in the photographing step, the tip is used. An image of the position reference constituent part is also photographed together, and the inspection information generating step is based on a photographed image of the chip and a photographed image of the position reference constituent part, and the positional relationship of the chip with respect to the position reference constituent part. 8. The spark plug inspection method according to claim 1, further comprising a chip position information generation step of generating information. 9. In the photographing step, the spark plugs are photographed from two or more directions different from each other, and in the inspection information generating step, photographed images of the chip and photographed images of the position reference constituent portion from the plural directions. 9. The spark plug inspection method according to claim 8, wherein the positional relationship information is generated by. 10. The ground electrode is bent back inward so that the base end side is coupled to the metallic shell while the tip side surface faces the tip end surface of the center electrode. With the shape, the ground electrode side tip is to be fixed to the tip side surface, in the tip position information generating step, the position reference component is the tip of the ground electrode,
Information relating to the center axis of the ground electrode tip and the distance a between the center point of the ground electrode side tip, 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 end surface of the ground electrode, and the position reference constituent part as the center electrode or the center electrode side tip, or the tip end surface of the center electrode or At least one of information relating to the facing distance e between the facing surface of the center electrode side chip on the ground electrode side and the facing surface of the ground electrode side chip on the center electrode side is generated as the chip position information. The spark plug inspection method according to claim 8 or 9. 11. The inspection information generating step, based on a photographed image of the ground electrode and a photographed image of the center electrode, a center axis of the tip of the ground electrode and a center axis of the center electrode or the center electrode. At least information related to the distance c from the central axis of the side tip, and information related to the distance d between the tip end surface of the ground electrode and the central axis of the central electrode or the central axis of the central electrode side tip; The spark plug inspection method according to claim 8, further comprising an auxiliary inspection information generating step of generating any of the auxiliary inspection information. 12. A photographing direction in which the center electrode and the ground electrode base end portion are seen to overlap each other such that the center electrode is on the front side and the ground electrode base end portion is on the rear side as viewed from the photographing means. Information relating to the distance c is generated based on a captured image in the frontal imaging direction, with the imaging direction that is substantially orthogonal to the frontal imaging direction around the central axis of the center electrode as the lateral imaging direction. The spark plug inspection method according to claim 10 or 11, 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 lateral imaging direction. 13. A photographing direction in which the center electrode and the base end of the ground electrode are seen to 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 as viewed from the photographing means. As a frontal photographing direction, in the photographing step, the spark plug is photographed from the frontal photographing direction prior to performing the bending process on the grounding electrode, so that the side surface of the ground electrode and the side surface are photographed. 12. The spark plug inspection method according to claim 8, further comprising a pre-bending photographing step for obtaining an image with the fixed ground electrode side chip. 14. The chip position information, wherein at least one of information related to the distance a and information related to the distance b is generated based on a captured image obtained in the pre-bending capturing step. Spark plug inspection method described. 15. The inspection information generating step, 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, Regarding the eccentricity from the central axis of the central electrode or the central axis of the central electrode side tip, a width direction eccentricity information generating step of generating ground electrode side tip width direction eccentricity amount information, information related to the distance b, and Based on the information related to the distance d, the ground electrode regarding the 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. The spark plug inspection method according to claim 11, further comprising at least one of an axial eccentricity information generation step of generating side chip axial direction eccentricity amount information. 16. The tip of the ground electrode is fixed to the tip of the ground electrode such that the facing surface of the ground electrode side facing the center electrode protrudes from the facing surface of the ground electrode facing the center electrode. In the process, the center electrode and the ground electrode base end are seen to overlap each other so that the center electrode is the front side and the ground electrode base end is the rear side when viewed from the shooting means. As a photographing direction, the ground electrode after bending is photographed from the front photographing direction, and in the tip position information generating step, a photographed image of the protruding portion of the ground electrode side tip and a photographed image of the center electrode or the center Based on the photographed image of the chip fixed to the electrode, the center axis of the center electrode of the ground electrode side chip in the ground electrode width direction is 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 side tip of the ground electrode side tip is fixed to the tip of the ground electrode so that the facing surface of the ground electrode side protrudes more than the facing surface of the ground electrode on the center electrode side. In the process, the center electrode and the ground electrode base end are seen to overlap each other so that the center electrode is the front side and the ground electrode base end is the rear side when viewed from the shooting means. The bending direction is taken as a lateral photographing direction around the central axis of the center electrode, and the photographing direction substantially orthogonal to the front photographing direction is taken as a lateral photographing direction, and the ground electrode after bending is photographed from the lateral photographing direction. In the generation step, based on a photographed image of the protruding portion of the ground electrode side tip and a photographed image of the center electrode or a tip fixed to the center electrode, the front in the ground electrode axial direction is obtained. 17. The ground electrode side chip axial direction eccentricity amount information regarding the eccentricity amount of the center axis line of the ground electrode side chip from the center axis line of the center electrode or the center axis line of the center electrode side chip is generated. Spark plug inspection method described in Crab. 18. A ground electrode side tip surface undulation state measuring step of measuring a surface undulation state of a facing surface of the ground electrode side tip on the side of the center electrode, prior to the bending of the ground electrode, and the ground electrode. Of the center electrode or the center electrode side chip and the ground electrode after the bending process, the photographing step, of the facing surface on the center electrode side of the ground electrode side chip, the measured Based on the information of the surface undulation state and the information of the photographed image, the facing surface of the ground electrode side chip on the side of the center electrode, the tip surface of the center electrode or the ground electrode of the center electrode side chip. 18. The spark plug inspection method according to claim 1, further comprising: the inspection information generating step of generating, as the inspection information, information related to a distance e from a facing surface on the side. 19. A chip for judging whether or not the chip fixed to the ground electrode satisfies a desired positional relationship with respect to a predetermined portion of the spark plug based on the inspection information. 19. The spark plug inspection method according to claim 1, comprising a position determination step and a chip position determination result output step of outputting the determination result. 20. If the result of the determination is negative, the tip satisfies the desired 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 center electrode, a ground electrode arranged so that a tip side thereof 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 spark plug inspection device, wherein the spark is provided so that an image of at least the tip and a portion of the center electrode or the ground electrode to which the tip is fixed (hereinafter referred to as a tip fixed portion) can be obtained. A photographing means for photographing the plug, a master image data storage 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 the master image data matching with the master image in the photographed image Chip discriminating means for discriminating the matching portion as a portion forming at least a part of the chip by searching the portion. And generating inspection information relating to 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 apparatus comprising: an inspection information generating unit that performs the inspection information output unit that outputs the generated inspection information. 22. A center electrode, a ground electrode arranged so that its 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. 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, 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 a captured image, and image information after the determination. On the basis of the above, information regarding the amount of eccentricity between the ground electrode or the tip on the ground electrode side and the center electrode or the tip on the center electrode side is generated as inspection information. 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 a master image of a shape corresponding to all or a part of the chip in advance, and searches a portion of the photographed image that matches the master image to find a matching portion thereof. Is determined as a portion forming at least a part of the chip, the inspection information generating means, between 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 regarding at least one of a size and a position of the chip is generated based on at least one of them. 24. A chip for judging, based on the inspection information, whether or not the chip fixed to the ground electrode satisfies a desired positional relationship with respect to a predetermined portion of the spark plug. 24. The spark plug inspection device according to claim 21, further comprising a position determination means and a tip position determination result output means for outputting the determination result. 25. If the determination result is negative, the ground electrode is subjected to a straightening process so that the tip satisfies the desired positional relationship with respect to the predetermined portion of the spark plug. 25. The ground electrode correcting means is included.
The described spark plug inspection device.