JPH08247724A - Method for evaluating wearing state of piston - Google Patents

Abstract

PURPOSE: To evaluate the wearing state of a piston without receiving any influence from the setting of an optical system, such as an illuminator, etc., and noise. CONSTITUTION: A method for evaluating wearing state of piston includes a first process (step S1) for coloring the side face of a piston in a specific color, second process (step S2) for operating an engine in which the piston is set, third process (step S3) for generating picture data about the side face of the piston by taking the image of the side face, and fourth process (step S4) for detecting the degree of wear of the worked grooves of the piston based on the brightness difference among the worked grooves in the picture data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston wear condition evaluation method, and more particularly to a piston wear condition evaluation method for evaluating the wear degree of a piston machining groove by image processing.

[0002]

2. Description of the Related Art Conventionally, piston hit evaluation (wear condition inspection) is performed visually or by precise measurement of a required portion. Also, a method for evaluating the wear condition by image processing has been filed by the same applicant (for example, Japanese Patent Application Nos. 5-347663 and 6-54460).
issue).

The hitting of the piston is an important factor for predicting in advance and determining the profile of the piston, especially against seizure of the engine, and is fed back to the design of the piston.

In the hit evaluation by image processing, attention is paid to a machining groove generated when the piston is formed, and the strength of the hit is evaluated based on the remaining amount. Since the same bit is used during machining, the depth of the machining groove is almost uniform in one piston. When the engine is actually operated against this uniform groove, the piston and cylinder rub against each other, causing the piston to hit (wear), the strength of which reduces the depth of the groove, which eventually wears out. Then it will disappear. Therefore, the hit strength can be estimated by measuring the remaining amount of the processed groove.

[0005]

However, in the case of visual observation, there are individual differences in evaluation, skill is required in evaluation, and it is difficult to quantify the evaluation. That is, there is an inconvenience that the evaluation level of each individual cannot be standardized.

Further, in the case of precision measurement, there is a disadvantage that it takes a lot of time and labor to carry out the entire circumference of the piston, and on the other hand, there is a problem of internal strain due to thermal stress, and therefore precision measurement is required. The measurements are not always good.

According to the evaluation method by image processing of Japanese Patent Application No. 5-347663, the resolution is rough, and only the portion where the processed groove is lost due to contact and the portion where the processed groove remains are detected. That is, the structure is such that only the presence or absence of the processed groove is evaluated, and it is not possible to detect and quantify the wear state (contact) of the processed groove in stages. Therefore, there is an inconvenience that the piston after the long-time operation can be evaluated, but the piston after the short-time operation cannot be evaluated because all the machining grooves remain.

Further, in Japanese Patent Application No. 6-54460, the piston is made of metal such as aluminum alloy, so that there is a problem that it is difficult to set the installation location of the illumination and the aperture of the camera.

FIG. 16 is an explanatory diagram showing a conventional method for evaluating the wear condition. FIG. 16 shows the shape of the machining groove of the piston after the operation and the output waveform of the CCD line sensor when this is imaged. As shown in the figure, the CCD sensor outputs a waveform having a size corresponding to the height of the crest of the machining groove due to reflection from the machining groove on the side surface of the piston. In the non-hit portion K, a substantially uniform CCD output waveform is obtained as shown in the figure, but as the hit becomes stronger, this waveform becomes smaller and finally becomes a substantially constant output.

In the conventional example, the feature amount is obtained from this waveform, and the hit value is evaluated by obtaining the correlation between the feature amount and the wear amount by using the crest value and average value of each machining groove. .

However, the waveform obtained from the processed groove was not ideal, and was a waveform affected by noise such as scratches and stains on the surface which did not hit. In particular, the depth of the processed groove is only a few [μm] to a few tens [μm], and the influence of noise on the waveform is large for the hit evaluation performed by its reflection, which is also a cause of error.

[0012]

It is an object of the present invention to improve the problems of the prior art, and in particular, to evaluate the wear condition of the piston without being affected by the setting of the optical system such as illumination or the noise. Its purpose is to provide a situation assessment method.

[0013]

Therefore, in the present invention, the first step of coating the side surface of the piston with a specific color, and
The second step of operating the engine in which the piston is set, the third step of generating image data of the piston side surface by imaging the side surface of the piston, and the difference in brightness for each machining groove in the image data. And a fourth step of detecting the degree of wear of the piston machining groove based on
The configuration is adopted.

As a second means, the fourth step is a step of specifying width information of the processed groove, a step of dividing the image data by the width information of the processed groove, and a crest value of brightness from the divided image data. A step of extracting an average value of brightness from the divided image data, and a step of evaluating the degree of wear based on the average brightness value and the peak value of each divided data. I am collecting.

As a third means, in the case where the fourth step is followed by the step of extracting the average brightness value from the divided image data, the average brightness value for each machining groove exceeds a predetermined threshold value. In addition, there is provided a step of determining that the crest value of each of the machining grooves is a crest value stronger than the intermediate degree of wear.

The present invention is intended to achieve the above-mentioned object by these means.

[0017]

First, in the first step, the side surface of the piston is coated with a specific color. Next, in the second step, the engine with this piston set is operated. This causes the piston to hit. Further, in the third step, the side surface of the piston is imaged to generate image data of the side surface of the piston. Then, in a fourth step, the degree of wear of the piston machining groove is detected based on the feature amount for each machining groove based on the image data.

In the fourth step, first, the peak value of each processed groove of image data is acquired. That is, the difference in brightness with the processed groove as one unit is acquired. Further, the average value of the brightness of each processed groove of the image data is acquired. Next, when the average brightness value of each machining groove exceeds a predetermined threshold value, it is determined that the crest value of each machining groove is a crest value stronger than the intermediate wear degree. This is because in the image data of the piston coated with a specific color, the low wear part and the high wear part have similar peak values, and in this case, the strength of wear is determined by the average value of the brightness. There is. This is because the part where the peak value is the highest has a value approximately in the middle of the brightness. Therefore, although it depends on the brightness value when the peak value is the highest, the wear degree of the processed groove is detected at a gradation value close to twice the gradation value of the brightness by hardware.

[0019]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a flow chart showing the construction of a piston wear condition evaluation method according to the present invention. As shown in FIG. 1, the piston wear condition evaluation method includes a first step of coating the side surface of the piston with a specific color (step S
1), a second step (step S2) of operating the engine in which the piston is set, and a third step (step S3) of generating image data about the piston side surface by imaging the side surface of the piston, And a fourth step (step S4) of detecting the degree of wear of the piston machining groove based on the feature amount of each machining groove based on the image data.

FIG. 2 is a flow chart showing details of the fourth step. The fourth step is a step of specifying the width information b of the processed groove (step S41) and a step of dividing the image data a by the width information b of the processed groove (step S42).
And a step of extracting a crest value of brightness from the divided image data c and an average value of brightness from the divided image data (step S43), and a feature consisting of the average value and crest value of the brightness of each divided data. And a step of evaluating the degree of wear based on the value d (step S44).

This will be described in detail.

In step S1, the piston 32 is coated with a specific color. In this embodiment, since the image data of the piston side surface is generated without being affected by the installation position of the illumination, the intensity of the illumination, etc., the piston side surface is coated with the surface within a range that does not affect the operation. This makes it possible to improve the reliability of the waveform of the machined groove and emphasize the feature amount d regarding the wear of the machined groove. In this embodiment, a black coating is applied to the side surface of the piston, and the hit evaluation is performed based on the result. The black color is used because the piston 32 has a light metallic color. As the coating agent 32A, molybdenum disulfide is used and is uniformly applied with a film pressure of several [μm]. The coating agent 32A may be any material as long as it has a lightness opposite to that of the piston 32 and does not affect the operation of the piston 32.

In step S2, the engine in which the black-coated piston 32 is set is operated.
In the engine design, it is difficult to predict the thermal expansion of the piston 32 and the like during operation and the flow of oil and air-fuel mixture.
There is a part where the operation cannot be predicted by the computer simulation, and the design item is judged by actually operating the designed piston and observing the hit generated on this piston. In this step S2, the piston 32 to be inspected is hit and the processed groove is worn.

In step S3, the side surface of the piston is imaged. Imaging (measurement) is performed in the vertical (axial) direction with a resolution of 0.014 [mm] so that the distance between the processed grooves is 10 [dot] or more. In the lateral (rotational) direction, the piston is rotated by 1 [degrees] to capture an image. Therefore, as shown in FIG. 3, with the size of the normal piston 32, the image data a is 5000 [elements] in the vertical direction and 360 [lines] in the horizontal direction.
It becomes an image of.

FIG. 4A shows a machining groove and a coating agent 32A on the side surface of the piston before the operation, and a CCD image-capturing this.
The output waveform of the line sensor is shown. FIG. 4B shows an example of a cross section of the processed groove when the processed groove is worn after the operation and an output waveform of the CCD line sensor. By applying a black coating to the surface of the piston, the waveform of the machined groove obtained from it is, as shown in FIG. 4 (A),
In a state without hitting, the black level is almost uniform. On the other hand, if the coating agent wears due to a hit,
As shown in FIG. 4B, when the processed groove appears, a bright portion is formed in the black level due to the reflection of the illumination, and the peak value becomes large. That is, in the portion N where the machining groove is worn due to the contact,
The peak value increases.

The brighter the area becomes, the larger the hitting area becomes, and the half of the machined groove is worn when the coating agent is black and the worn piston is the white part of the reflected light of the piston. Furthermore, as wear progresses,
The black part of the coating agent is less than the white part,
In the portion S where the peak value becomes smaller and the processed groove disappears,
Bright and uniform output.

The vertical waveform of such a piston is 1
If 360 [degrees] are accumulated for each [degree], as shown in FIG. 5, a developed image in which the piston side surface of 5000 [dot] in the vertical direction and 360 [dot] in the horizontal direction is enlarged in the vertical direction is obtained. This image data a is multi-gradation image data a, and since it is not necessary to see the color tone in the evaluation of the hit and the piston 32 is mostly gray which is the color of aluminum, the R of the CCD line sensor is used.
The evaluation is performed on the gray image of the red (Red) component, which has the best sensitivity among the three GB colors.

In step S4, the degree of wear of the machining groove is detected based on the image data a on the side surface of the piston imaged in step S3.

In step S41, the width information b of the processed groove is specified. Since the pitch (width) of the machined groove is constant depending on the piston, it is determined in advance, or the clearly visible part of the machined groove is displayed on the CRT or the like, and the pitch of the machined groove is determined from there. In this method, a portion where only the coating agent is worn due to a hit is visually searched on the CRT, the portion is enlarged and displayed, and the pitch of the processed groove is obtained as the number of dots.

In step S42, the image data a is divided according to the width information b of the processed groove. In the present embodiment, the image data a is simply divided by the width (eg_wid) of the processed groove, and the strength of contact of the processed groove is calculated by obtaining the feature amount of the divided image data (waveform). And Here, the average value and the crest value (difference between the maximum value and the minimum value) of each machining groove are used as the feature amount.

As shown in FIG. 6, since there is no great difference between the machining grooves adjacent to each other, if the pitches (eg_wid) of the machining grooves are known, the characteristic amount (MAX1, MIN1, MIN1, MIN1,
M.H1, AV1) and the feature quantity (MAX
2, MIN2, M.H2, AV2) are almost the same value. Therefore,
If the evaluation target area is fixed, it is possible to perform a hit evaluation by simply dividing the area by (eg_wid) and obtaining the feature amount for each divided portion. Here, especially the peak value (MH [n])
And the average brightness value are used as characteristic values corresponding to the wear amount of the piston machining groove.

Further, in this embodiment, the machining groove is simply divided by the width (eg_wid) of the machining groove regardless of the fact that the machining groove exists spirally on the side surface of the piston. Therefore, the cutting position of the machining groove waveform differs in the left-right direction of the side surface of the piston, but this does not affect the evaluation result.

In step S43, the feature amount is calculated for each machining groove based on the divided image data c. FIG. 7 is a graph showing the correlation between the feature amount of the processed groove waveform and the hit strength. The dotted line in the figure is the characteristic amount of the conventional method which is not coated. As can be seen from the figure, the part where no hit occurs due to the coating is black, and the part that is worn due to the hit turns white due to the reflection of the illumination, so compared to the conventional example indicated by the dotted line, The change is very large, and the accuracy for estimating the amount of wear due to a hit is significantly improved.

However, the average brightness value for each processed groove has a proportional relationship with the hit strength as in the conventional method, but since the crest value does not have a simple proportional relationship, the information of the average brightness value is used here. Moreover, by determining whether the peak value is weaker or stronger than the middle hit value, it can be used as a feature value of the machining groove waveform similar to the conventional method.

That is, in step 44, when the average brightness value for each machining groove exceeds a predetermined threshold value, it is determined that the crest value for each machining groove is a crest value stronger than the intermediate wear degree. ing. This threshold value is obtained from the average brightness value of the image data a.

As described above, by applying the black coating to the piston, the feature amount used for the correlation of the hit strength can be emphasized as compared with the conventional method, and by combining the average brightness value and the peak value, the basic method Is the same as the conventional one, but it is possible to significantly improve the evaluation accuracy.

Further, since the crest value folds back at the middle point of the wear degree, it is possible to determine the hit strength with a gradation number that is nearly double that in the conventional example.

Further, after the winning strength is calculated, the result is displayed and output with the accuracy required for the evaluation. This is done, for example, by dividing the strength of hit into five stages and printing out with a color printer.

Next, an apparatus for carrying out the piston wear condition evaluation method according to the above-described embodiment will be described.

FIG. 8 is a block diagram showing a schematic configuration of hardware resources of the piston wear condition evaluation device. The data input means 1 is a piston imaging unit 2 that images a piston.
2, a stage control unit 21 that drives and controls the piston image pickup unit 22, and a data input unit 20 that temporarily stores the image data a picked up by the piston image pickup unit 22 and then inputs the image data a to the data processing unit 2. There is.

The piston image pickup unit 22 photoelectrically converts the reflected light from the piston 32, a CCD sensor 38, a rotary stage base 33 for rotating the piston 32, a rotary stage motor 35 for rotationally driving the rotary stage base 33, and the like. Is equipped with.

The stage controller 21 includes a motor driver 56 for controlling the operation of the rotary stage motor 35.
And a CCD driver 61 for driving and controlling the CCD sensor 38 and outputting a photoelectrically converted signal to the data input section 20. The motor driver 56 rotates the rotation stage base 33 by an angle of rotation that matches the piston diameter based on a rotation request from the data processing means 2 when data is fetched.
To rotate. The rotation angle is calculated by the data processing unit 2, and a pulse corresponding to the rotation angle is sent to the motor driver 56 to drive the rotation stage motor 35.

The data input section 20 includes a CCD driver 61.
It is provided with an A / D converter 29 for converting the signal from A to D into a digital data and a memory 28 for storing the image data a from this A / D converter 29. Memory 28
Is a 4-Mbyte SRAM so that it can hold data for one round. The developed image of the side surface of the piston (image data a) stored in the memory 28 is accessed by the data processing means 2 for evaluating the wear state of the piston.

In the present embodiment, the data processing means 2 is a PI for interfacing with a personal computer (PC).
An O board and an image board (frame buffer) for full color processing are added. As a configuration, the data processing unit 2 receives a PIO 23 that serves as an interface for transmitting and receiving data with the data input unit 1, a CPU 29 that executes step S4 shown in FIG. 1, and an input of machining groove width information b and the like. And an input unit 25. The processing time of the data processing means 2 depends on the processing capacity of the PC.

For the evaluation of the side surface of the piston performed by the data processing means 2, a means for displaying and outputting the evaluation result is required. The evaluation result output means 3 saves the evaluation result data and outputs the evaluation result for display. Various disks can be considered as the disk 26 for storing the evaluation results, but since the image data is large, only a few data can be stored in one normal floppy disk. On the other hand, hard disks, high-density floppy disks,
Data storage efficiency can be improved by using a magneto-optical disk or the like. Further, as for the output of the result, an ordinary printer is sufficient if only the numerical value is output, but the printer 33C for full color is required to output the image data. Therefore, the processing software is made to correspond to them as what is determined according to the application.

FIG. 9 is a block diagram showing the detailed structure of the data input section 20. The data input section 20 outputs the R output from the CCD sensor 38 under the control of the CCD driver 61.
An amplifier that amplifies each analog signal for each GB (AM
P) 50, MODE signal from PIO23 and REQ
And a multiplexer 51 that switches the output of the analog signal from the amplifier 50 based on the signal.

The data input section 20 further includes an A / D converter 29 for converting the analog signal from the multiplexer 51 into a digital signal, and the A / D converter 2.
RAM 54 for storing the digital data (image data a) output from the A / D converter 29, an address counter 53 for designating the address of the RAM 54 when storing the data output from the A / D converter 29, #BUS. The bus controller 55 is provided for controlling the access right to the RAM 54 based on the CTL signal. In this embodiment, the RAM 5
4 is accessed by the PIO 23 and the A / D converter 29 based on the setting of the access right.

The specifications of each signal line in the figure are as follows. MODE: Since this data input means 1 is also used for evaluating the contamination of the piston, it is necessary to switch between the hit evaluation and the contamination evaluation. That is, at the time of dirt evaluation, the data acquisition is performed in the order of R → G → B → R → ...
The signal from the sensor 38 is read and the data for one line is sent to the A / D converter 29. Further, at the time of hitting evaluation, signals of R and R ′ are read from the CCD sensor 38 in the order of R → R ′ → R → ...
And the data of R ′ are sent to the A / D converter 29. It is a switching signal for these. In addition, since 1250 elements per line are used for dirt evaluation, ODD for each of RGB is used.
1250 out of 2500 elements are used. In the one-sided evaluation, both ODD and EVEN of the R element are used as data for 5000 elements. Since the outputs of the CCD sensor in this embodiment are ODD and EVEN separately, they are used as the R signal and the R ′ signal. (L: dirt,
H: hit)

#BUS. CTL: A signal for changing the access right for writing and reading to the RAM 54 on the memory board 28. Writing is possible when the piston 32 is imaged, and the data input means 1 controls the writing of data to the RAM 54. At the time of data processing such as dirt evaluation, the RAM 54 is separated from the data input unit 1, and the data processing unit 2 controls the data to access the data in a readable and writable state.
(L: data input means 1 controls RAM 54, H: data processing means 2 controls RAM 54)

DATA: A data bus handles 16-bit data. ADR: An address bus uses 24 bits to handle a 4-Mbyte data address. STAT: Outputs H during execution of A / D conversion. REQ: Outputs H during measurement. DIR: Determines the data access method from the PC side to the RAM (H: read, L: write). R / W: Indicates the timing of writing data from the PC side to the RAM. (L: At the start of writing, D
Write ATA)

FIG. 10 is an explanatory diagram showing a detailed structure of the stage control unit 21. Stage control unit 2
Reference numeral 1 denotes a motor driver 56 for driving and controlling the rotary stage motor 35, and a CC for driving and controlling the CCD sensor 38.
And a D driver 61. Motor driver 56
Controls the rotary stage motor 35 by the following signals.

PLUS: Outputs the rotation pulse of the stepping motor. DEF: Designates the rotation direction. H. OFF: Cuts off the current when the motor is stopped. TIM: Motor timing output signal. O. H: Motor overheat output signal.

The CCD driver 61 is the CCD sensor 38.
The LATCH signal is used to change the storage time of the. (L: initial value)

The stage controller 21 includes a first stage sensor 58 for detecting the origin position of the rotary stage base 33, a second stage sensor 59 for determining the type of the piston fixing jig 31, and a camera lock mechanism 30. A lock sensor 57 for detecting the state is provided. The various sensors differ depending on the configuration of the piston imaging unit 22.

FIG. 11 shows a piston image pickup unit 2 according to this embodiment.
It is a front view which shows the structure of 2. The piston imaging unit 22 is
Piston fixing jig 31 that accepts mounting of the piston 32
A rotary stage base 33 to which the piston fixing jig 31 is fixed, a rotary stage motor 35 for rotationally driving the rotary stage base 33, lenses 37 and C.
A camera 36 having a CD sensor 38, and this camera 36
To the piston 32 fixed to the piston fixing jig 31. The position adjusting shaft 41 adjusts the distance.

Moreover, the camera 36 is attached to the piston fixing jig 3
The camera tension spring 39 is biased toward the first side, and the sliding member 40 is located on the piston fixing jig 31 side of the position adjusting shaft 41 and is in contact with the piston fixing jig 31. Here, the sliding member 40 is a rotation bearing that abuts the side surface of the piston support portion 3B of the piston fixing jig 31.

FIG. 12 shows the piston image pickup unit 2 shown in FIG.
It is a top view which shows the structure of 2. The camera 36 has a base 4
3 is located on the slide rail 42, and when it is pulled toward the piston 32 (direction A in FIG. 12) by the camera tension spring 39, the camera moves on the slide rail 42. Therefore, the movement of the camera 36 is a linear movement. Further, the camera 36 stops at the camera frontmost position 42A regardless of the piston fixing jig 31.

The distance from the piston surface of the camera 36 is always constant regardless of the diameter of the piston 32.
That is, the camera 36 is always pulled toward the piston (direction A in FIG. 12) by the camera tension spring 39, and even if the piston 32 rotates during the measurement, the piston fixing jig 31 and the rotation bearing 40. Since and are in contact with each other, the distance between the piston 31 and the camera 36 is constant. Furthermore, even if the diameter of the piston 32 changes, the distance between the piston 32 and the camera 36 can be kept constant by exchanging the piston fixing jig 31 with a new one according to the diameter of the new piston 32.

The camera 36 is provided with a camera lock mechanism 30 for locking the camera position rearward via a link mechanism portion 47 in the direction opposite to the piston 31. In this embodiment, the camera tension spring 39 causes the camera 36 to always move the piston fixing jig 31 via the position adjusting shaft 41.
Is pressed against. Therefore, the new piston 32
When the piston fixing jig 31 is exchanged to capture the image, or when the piston imaging unit 22 is moved, the camera 36 needs to be lowered backward (direction B in FIG. 12). This is achieved by the camera lock mechanism 30.

As shown in FIGS. 11 and 12, the lock mechanism 30 of the camera has a link mechanism portion 47 which is a flat plate whose one end is rotatably fixed to the camera 36, and a handle 46 which lowers the camera rearward by rotational movement. And this handle 4
6 includes a rotating plate 48 that rotates together with the rotating plate 6, and a flat plate 47B that follows the rotating plate 48 and moves the link mechanism portion 47 rearward.

Moreover, the rotary plate 48 is provided with receiving holes 48A and 48B for the ball blankers 49, respectively. The receiving hole 48A of this ball blanker 49,
48B is provided corresponding to the lock position of the camera 36 and the camera position during piston imaging.

At the time of measuring the piston (at the time of picking up a developed image of the side surface of the piston), the rotary plate 48 is fixed by the ball blanker 49 at the position of the receiving hole 48A. At this time, the position of the camera 36 moves back and forth depending on the diameter of the piston fixing jig 31 corresponding to the diameter of the piston 32. However, the play portion 47A of the link mechanism portion 47 is free from the lock mechanism, and the camera position is determined by the camera tension spring 39 and the position adjusting shaft 41.

However, when the piston fixing jig 31 is replaced, the camera must be lowered in the direction of the symbol B in FIG. Then, the rotating plate 48 is rotated by the handle 46 in the direction of the symbol F in FIG.
The rotating plate 48 is locked by combining with the ball blanker 49 at B. Then, the camera 36 moves in the direction of symbol B in FIG. 12 via the link mechanism 47, the gap between the position adjusting shaft 41 and the piston fixing jig 31 increases, and the piston fixing jig 31 can be replaced. .

FIG. 13 is a sectional view showing a state where the piston 32 is installed on the piston fixing jig 31. The piston fixing jig 31 includes a cylindrical piston support portion 31B having the same diameter as that of the piston 32 to be fixed, and a piston set portion 31A located at one end of the piston support portion 31B for receiving the mounting of the piston. The piston support portion 31B is configured such that its diameter is the same as the diameter of the piston 32 to be imaged. The phantom line in FIG. 13 is the piston 3.
2 shows that the piston 32 is the piston setting part 31.
When installed in A, the side surface of the piston 32 is flush with the side surface of the piston fixing jig 31. Further, in this embodiment,
Due to image processing, the surface of the piston fixing jig 31 is colored differently from the piston 32 and the coating material.

FIG. 14 is a sectional view showing the fixation of the piston fixing jig 31 to the rotary stage base 33. The inside of the piston fixing jig 31 has a bottomed hole 31C, and the piston fixing jig 31 is mounted on the piston fixing jig setting portion 33A of the stage base 33 by the bottomed hole 31C.
Furthermore, the piston fixing jig 31 and the rotary stage base 33 are fixed to each other by coupling the receiving hole 31D provided on the side surface of the piston fixing jig 31 and the tip of the ball blanker 34 mounted on the rotary stage base 33. To be done.
Further, the ball blanker 34 and the receiving hole 33D of the ball blanker are threaded, so that the rotary stage base 33 and the ball blanker 34 are fixed to each other.

FIG. 15 is a view showing a state in which the piston fixing jig 31 is mounted on the rotary stage base 33.
15A is a plan view thereof, and FIG. 15B is a right side view thereof. The piston fixing jig 31 includes a jig confirmation shutter 31.
E is provided. By providing the jig confirmation shutter 31E, the second stage sensor 59 described above can determine the type of jig by the difference in the rotation angle from the origin position of the rotary stage base 3. Since the piston fixing jig 31 is configured according to the shape of the piston, the type of the set piston 31 can be determined by determining the type of the piston fixing jig 31. On the other hand, the rotary stage base 33 is also provided with an origin confirmation shutter 33E, and the first stage sensor 58 causes the rotary stage base 3 to rotate.
The origin position of 3 is confirmed. The stage sensors 58 and 59 detect the positions of the shutters 1E and 3E by an optical sensor (not shown).

[0068]

Since the present invention is constructed and functions as described above, according to this, in the first step, the side surface of the piston is coated with a specific color. The difference in brightness between the as-coated and as-coated part becomes large. Therefore, in the third step, it is possible to generate image data having a large lightness difference on the side surface of the piston. Further, in the fourth step, the degree of wear of the piston machining groove is detected based on the image data in which the difference in lightness is increased due to the coating, so that it is possible to perform the hit evaluation while minimizing the influence of noise. As described above, it is possible to provide an unprecedented excellent piston wear condition evaluation method capable of evaluating the wear condition of the piston without being affected by the setting of the optical system such as illumination and the influence of noise.

In the fourth step, the average value of brightness is extracted from the divided image data, and when the average brightness value for each machining groove exceeds a predetermined threshold value, the peak value for each machining groove is obtained. Is determined to be a peak value that is stronger than the average wear level,
Even if the crest value turns back at an intermediate value of the hit strength, the wear condition can be evaluated by the same method as the conventional method.

[Brief description of drawings]

FIG. 1 is a flow chart showing processing steps of an embodiment of the present invention.

FIG. 2 is a flowchart showing detailed processing steps of step S4 shown in FIG.

FIG. 3 is an explanatory diagram showing a piston and image data which is developed data of a side surface of the piston.

[Fig. 4] Machining groove on the side of piston and coating agent and C
It is explanatory drawing which shows the relationship with a CD sensor waveform, and FIG.
FIG. 4A is an explanatory diagram showing a machining groove and a coating agent on the side surface of the piston before operation, and an output waveform of a CCD line sensor which images this, and FIG. 4B is a case where the machining groove after operation is worn. FIG.

FIG. 5 is an explanatory diagram showing an example of the wear situation of the processed groove in the image data captured in step 3 of FIG.

FIG. 6 is an explanatory diagram showing an example of a dividing process according to the width of a processed groove in step S42 of FIG.

FIG. 7 is an explanatory diagram showing a relationship between a feature amount for each machining groove shown in FIG. 6 and a wear condition (contact strength).

FIG. 8 is a block diagram showing a configuration of a piston wear condition evaluation device.

9 is a block diagram showing a detailed configuration of a data input unit shown in FIG.

10 is a block diagram showing a detailed configuration of a stage control unit shown in FIG.

11 is a side view showing the configuration of the piston imaging unit shown in FIG.

12 is a front view of the piston imaging unit shown in FIG.

13 is a cross-sectional view showing a state in which a piston is installed on the piston fixing jig shown in FIG.

14 is a cross-sectional view showing a state where the piston fixing jig shown in FIG. 11 is mounted on a rotary stage base.

15 is a view showing a state in which the piston fixing jig shown in FIG. 11 is mounted on a rotary stage base, and FIG.
Is a front view thereof, and FIG. 15B is a right side view thereof.

FIG. 16 is an explanatory diagram showing a relationship between a conventional processed groove and a CCD sensor waveform.

[Explanation of symbols]

 a image data b width information of processed groove c divided image data d feature amount 32 piston 32A coating agent

Claims (3)

[Claims] 1. A first step of coating a side surface of a piston with a specific color, a second step of operating an engine in which the piston is set, and an image of the side surface of the piston to generate image data of the side surface of the piston. 3rd to do
And the fourth step of detecting the degree of wear of the piston machining groove based on the feature amount for each machining groove based on the image data. 2. A fourth step is a step of specifying width information of the processed groove, a step of dividing the image data by the width information of the processed groove, and a crest value of brightness from the divided image data. A step of extracting, a step of extracting an average value of brightness from the divided image data, and a step of evaluating the wear degree based on the average brightness value and the crest value for each divided data, The method for evaluating the wear of a piston according to claim 1. 3. The method according to claim 4, wherein in the fourth step, following the step of extracting an average value of lightness from the divided image data, the average lightness value of each machining groove exceeds a predetermined threshold value. 3. The piston wear condition evaluation method according to claim 2, further comprising a step of determining that the crest value of each of the processed grooves is a crest value stronger than an intermediate degree of wear.