JP4005964B2 - Piston ring inspection method and apparatus - Google Patents

Description

  The present invention is directed to, for example, a piston before being incorporated in an automobile engine or the like, and an inspection method for piston rings assembled in a plurality of ring grooves formed at predetermined intervals in the axial direction on the outer periphery of the piston. And an apparatus for the same.

  A plurality of piston rings such as a top ring, a second ring, a side rail upper ring, and a side rail lower ring are assembled in the plurality of ring grooves of the piston by a piston ring assembling machine or the like. At that time, forgetting to assemble, poor assembly where the circumferential positions of the piston ring joints are aligned and aligned, and the piston ring itself is deformed by the assembly force etc. If the abnormal condition such as the width of the cylinder changes beyond a predetermined value remains, the original performance of the piston ring, that is, the airtightness between the piston and the cylinder inner wall may be impaired when the piston is incorporated into the engine. Further, the scraping performance of the lubricating oil on the inner wall of the cylinder may be insufficient, which may cause various adverse effects on the engine operation. Therefore, after assembling the piston rings in the plurality of ring grooves on the outer peripheral surface of the piston, confirm the presence / absence of each piston ring, confirm the circumferential position of each piston ring joint, and determine whether the width of each piston ring joint is acceptable. Inspection work is essential.

  As a method for inspecting such a piston ring, in general, an operator generally picks each piston after assembly of the piston ring and visually confirms the presence or absence of the piston ring, confirms the circumferential position of the joint portion, and A pass / fail judgment was made on the width of the abutment.

  However, in the case of the conventional visual inspection method as described above, not only troublesome work is required, but also the inspection time takes a long time, and the assembly of the piston ring is completed because it is not in time for the assembly line tact of the engine. It is necessary to secure a space for stocking a large number of pistons for inspection. In addition, since it is only necessary to check the presence or absence of the piston ring and the circumferential position of the abutment portion, it is possible even for an unskilled person. There is a problem that it cannot be determined accurately unless it is a skilled worker with abundant technical knowledge.

  The present invention has been made in view of the above-described circumstances, and its purpose is not only to confirm the presence / absence of the piston ring and the circumferential position of the abutment portion, but also to determine whether or not the width of the abutment portion is acceptable. An object of the present invention is to provide a piston ring inspection method and apparatus capable of easily, quickly and accurately determining.

  An inspection method for a piston ring according to the present invention devised to achieve the above object is an inspection method for a piston ring assembled in a plurality of ring grooves formed at predetermined intervals in the axial direction on the outer periphery of the piston. Then, light in a direction inclined with respect to the piston radial direction is irradiated from the side position of the piston toward the piston ring assembly position, and in this light irradiation state, the piston is rotated around its axis to By taking an image of the entire circumference of the outer peripheral surface with a camera from the side position of the piston, the presence or absence of the piston ring and the circumferential position of each piston ring joint are confirmed, and each piston is processed by data processing of the captured image. It is characterized by determining pass / fail of the width of the ring joint portion.

  Also, the piston ring inspection device according to the present invention devised to achieve the same object as described above is assembled to a plurality of ring grooves formed at predetermined intervals in the axial direction on the outer periphery of the piston. An inspection device for a piston ring, which is disposed at a side position of the piston and irradiates light in a direction inclined with respect to the piston radial direction toward the piston ring assembly position, and the piston around its axis Piston rotation mechanism that rotates, a camera that is arranged at a side position of the piston and that captures an image of the entire circumference of the outer periphery when the piston rotates, and a pass / fail determination of the width of each piston ring joint by data processing of the captured image And a means for displaying a screen.

  According to the piston ring inspection method and apparatus therefor according to the present invention having the above-described characteristic configuration, the direction of inclination with respect to the piston radial direction from the side position of the piston toward the position where a plurality of piston rings are assembled. When the piston ring is normally assembled in the ring groove, the piston is rotated around its axis and the image of the entire circumference of the piston is taken with the camera. Sometimes the strongest light irradiation site on the outer peripheral surface of each piston ring is linearly projected at different positions on the image, so it is only necessary to observe the position of the linear site projected on the image. Whether or not each is assembled in the corresponding ring groove as prescribed, that is, whether or not there is each piston ring and the circumferential position of each piston ring joint And it can be confirmed quickly. In addition, the width of the piston ring joint portion obtained by data processing of the captured image is displayed on the screen, or an allowable range value is input in advance as the width of the piston ring joint portion. By comparing the numerical value obtained by data processing of the captured image and displaying the result of pass / fail judgment of the piston ring joint part on the screen, even a skilled or less experienced operator can judge the joint part pass / fail result. It can be determined very easily and accurately. Therefore, it is only necessary to observe and read the image obtained by irradiating light toward the piston ring assembly position and the data displayed on the screen as a result of data processing of the image. Not only can efficiency be realized, but also an effect that a highly reliable inspection can be performed.

  In the piston ring inspection method and apparatus according to the present invention, as described in claim 2 and claim 5, the ring extrusion roller is pressed against the piston outer peripheral surface from the side opposite to the light irradiation position and the camera photographing position. When the piston ring is normally assembled in the ring groove by shooting the image of one round by projecting the outer peripheral surface portion of each piston ring to the outside of the outer peripheral surface of the piston The contrast between the site with the strongest light that is projected linearly at different positions on the image and when it is not so large can be taken, the presence or absence of piston rings on the screen and the circumference of each piston ring joint The confirmation of the direction position can be made easier and more accurate.

  The irradiation light and the light source may be any, but it is particularly desirable to use a laser beam and a laser having strong directivity as described in claims 3 and 6, and in this case, any Even in the inspection under the work environment, it is possible to accurately perform predetermined inspections such as confirmation of the presence / absence of the piston ring, the circumferential position of each piston ring joint portion, and determination of pass / fail of the width of the joint portion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic plan view of the entire inspection apparatus used in the piston ring inspection method according to the present invention, FIG. 2 is a side view of the main part thereof, and FIG. 3 is a longitudinal front view of the main part of the inspection apparatus. 1 to 3, reference numeral 1 denotes an apparatus frame that is supported by a stand 2 erected on a floor surface via an air cylinder (not shown) so as to be movable up and down. The apparatus frame 1 has a cylindrical bearing with a bearing 3 a. The vertical axis 4 is rotatably supported via the member 3.

  At the lower end portion of the vertical axis 4 is a piston 5 which is accommodated and held in a vertically oriented posture on a pallet (not shown) loaded on a horizontal transfer conveyor and carried into the inspection apparatus. A piston hand unit 6 that is sandwiched and raised to a predetermined height is equipped, and a rotary encoder 7 is directly connected to the upper end. The vertical axis 4 is linked to a speed control motor 11 fixed to the apparatus frame 1 via timing pulleys 8 and 9 and a timing belt 10. The speed control motor 11, the vertical axis 4, The hand unit 6 constitutes a piston rotating mechanism for driving and rotating the piston 5 around its axis, that is, the longitudinal axis a.

  A frame located on one side in a direction orthogonal to the moving direction (arrow A in FIG. 1) in the piston moving path from the carry-in port 12 of the piston 5 to the carry-out port 13 of the piston 5 after the inspection by the pallet. A laser (light source) that irradiates a laser beam LB toward the piston ring assembly position on a plurality of ring grooves 14 formed at predetermined intervals in the axial direction on the outer peripheral surface of the piston 5 15 and a CCD camera 16 for taking an image of the outer peripheral surface of the piston 5 irradiated with the laser beam LB.

  Further, on the side opposite to the arrangement side of the laser 15 and the CCD camera 16, that is, on the other side position in the direction orthogonal to the moving direction A in the piston moving path, the piston moving path is provided via the air cylinder 17. On the other hand, a movable frame 18 that can move toward and away in the direction of the arrow xy is provided, and a pair of piston ring push rollers 19 and 19 to be described later are attached to the movable frame 18. Further, the CCD camera 16 is connected to a PC 20 that performs data processing on the photographed image and displays a screen of the processing result.

  In FIG. 1 and FIG. 2, the vertical axis 4 with the hand unit 6, the laser 15, the CCD camera 16, and the piston ring push-out are provided so that three pistons 5 carried into the piston movement path can be inspected simultaneously. Although each of the pair of rollers 19 and 19 is shown with three sets arranged at appropriate intervals in the piston movement direction A, the piston 5 may be inspected one by one. Will only describe the configuration of one piston ring inspection device.

  As clearly shown in FIGS. 4 (a) and 4 (b), the top ring 21a is formed in a plurality of ring grooves 14 formed on the outer peripheral surface of the piston 5, specifically, the three ring grooves 14a to 14c. The four piston rings 21 commonly referred to as the second ring 21b, the side rail upper ring 21c, and the side rail lower ring 21d are arranged so that their circumferential positions of the joint portions 21B (21a1, 21b1, 21c1, 21d1) are slightly shifted. Is assembled through a piston ring assembly machine or the like.

  The laser 15 is arranged and fixed on the frame portion 1a in an inclined posture such that the laser beam LB emitted from the laser 15 is directed in a direction inclined with respect to the piston radial direction and irradiates the outer peripheral surface of the piston. At the same time, the CCD camera 16 is disposed and fixed on the frame portion 1a in an inclined posture so as to obtain an image with the most intense light irradiation position of the laser beam LB as the center. The tilt angle of the laser 15 and the CCD camera 16 is configured to be adjustable.

  As shown in FIGS. 5 and 6, the pair of rollers 19 and 19 for extruding the piston ring are swingable around the support shafts 23 and 23 at two left and right positions of the bracket 22 fixed to the movable frame 18. A pair of rollers 19, 19 are restricted by stoppers 25, 25 between the other ends of the bell cranks 24, 24 and supported at the tip ends of the pivoted bell cranks 24, 24 so as to be freely rotatable. A spring 26 that oscillates and biases in a direction approaching each other is interposed, whereby the movable frame 18 moves closer to the piston movement path side as indicated by the phantom line in FIG. , 19 are in contact with the outer peripheral surface of the piston 5, the bell cranks 24, 24 are swung away from each other against the biasing force of the spring 25, and are elastically pressed by the pair of rollers 19, 19. It is configured to pop the outer peripheral surface portion 21A of the light irradiation and the camera imaging side of the piston ring 21 to the outside of the piston 5 the outer peripheral surface.

Next, an inspection method (procedure) by the piston ring inspection apparatus configured as described above will be described.
When the pallet holding and holding the piston 5 in the vertical orientation is carried into the piston movement path inside the inspection apparatus by the horizontal transfer conveyor and stopped at a predetermined position, the apparatus frame 1 is lowered and the lower end of the vertical axis 4 The hand unit 6 sandwiches the piston 5, and the piston 5 is raised to a predetermined height position as shown in FIG.

  Next, the speed control motor 11 starts to operate, and the rotational force thereof is transmitted to the vertical axis 4 via the timing pulleys 9 and 8 and the timing belt 10 and is sandwiched between the vertical axis 4 and the hand unit 6 provided at the lower end thereof. The piston 5 is rotated about the longitudinal axis a. At this time, the movable frame 18 is moved closer to the piston movement path side via the air cylinder 17 as shown by the phantom line in FIG. 1, and the pair of rollers 19 and 19 attached to the movable frame 18 is moved to the piston. Since the outer peripheral surface of the piston 5 is elastically pressed, the outer peripheral surface portion 21A on the light irradiation and camera photographing side of each piston ring 21 jumps out of the outer peripheral surface of the piston 5, as shown in FIG. In this state, the vertical axis 4, the piston 5, and the piston ring 21 are driven and rotated by one round of the outer peripheral surface of the piston based on the number of pulses set in the rotary encoder 7.

  The laser 15 is operated in parallel with the rotation of the vertical axis 4, the piston 5 and the piston ring 21, and the laser beam LB emitted from the laser 15 is inclined with respect to the piston radial direction as shown in FIG. Irradiation is performed from the direction to the piston ring assembly position, and the CCD camera 16 is operated to capture an image of the entire circumference of the piston 5.

  Here, since the laser beam LB irradiates the portion that protrudes outward most at the piston ring assembly position, each piston ring 21 (21a to 21d) is normally assembled in the ring groove 14. In some cases, as shown in FIG. 9, a plurality of ring grooves 14 in which the line L1 of the outer peripheral surface portion 21A of the protruding piston ring 21 which is the strongest light irradiation portion of the piston ring 21 becomes the strongest light irradiation portion among the other portions. As shown in FIG. 10, when the piston ring 21 is displaced to one side of the line L2 of the outer peripheral surface portion of the piston and projected on the image P, and each piston ring 21 is not assembled in the ring groove 14, Since the line L3 corresponding to each ring groove 14 is shifted to the other side of the line L2 of the piston outer peripheral surface portion between the ring grooves 14, the line L3 is projected on the image P. By simply observing the position of line 1 or L3 with respect to line L2, whether or not each piston ring 21 is assembled in a predetermined manner in the corresponding ring groove 14, that is, the presence or absence of each piston ring 21 and each piston ring joint portion The circumferential position of 21B (21a1, 21b1, 21c1, 21d1) can be easily and quickly confirmed.

  Further, the one-round image taken by the CCD camera 16 is input to the PC 20 and processed, and a monitor screen S as shown in FIG. 11 is displayed on the display. Confirm the width w of the piston ring joint portion displayed on the monitor screen S (see FIG. 4B), or input the allowable range numerical value in advance to the PC 20 as the width of the piston ring joint portion. The result of pass / fail judgment (OK or NG) of the width of the piston ring joint portion is displayed on the monitor screen S by comparing the stored allowable numerical value with the numerical value obtained by the data processing of the photographed image. By doing so, even an operator with little skill and experience can determine the pass / fail of the width of the joint portion very easily and accurately.

  It should be noted that by changing the number of pulses set to the rotary encoder 7, pistons of various sizes (diameters) having different outer diameters can be inspected and applied to the inspection of the piston ring having the above contents. Is possible.

  As described above, a CCD camera is most preferable as the camera, but it may be a digital camera or a video camera.

It is a schematic plan view of the whole inspection apparatus used for the inspection method of the piston ring concerning the present invention. It is a side view of the principal part of the whole inspection apparatus. It is a vertical front view of the principal part of the inspection apparatus. (A) is a longitudinal cross-sectional view of a piston ring assembly piston to be inspected, and (b) is an external front view thereof. It is an enlarged plan view of the principal part in an inspection device. It is an enlarged side view of the principal part in the inspection apparatus. It is a principal part enlarged front view which shows the state at the time of the test | inspection start by the same inspection apparatus. It is a top view of the principal part which shows roughly the inspection condition by the inspection device. It is a figure of the picked-up image projected on a camera, when each piston ring is normally assembled | attached in the ring groove (it exists). It is a figure of the picked-up image projected on a camera when each piston ring is not assembled | attached in the ring groove (none). It is a figure of the monitor screen obtained by the data processing of the picked-up image for one round, and displayed on the display of PC.

Explanation of symbols

5 Piston 14 (14a-14d) Ring groove 15 Laser (light source)
16 CCD camera 19 Piston ring extrusion roller 20 PC (data processing and display means of photographed image)
21 (21a to 21d) Piston ring 21A Projecting outer peripheral surface portion 21B Piston ring joint LB Laser beam

Claims (6)

An inspection method for piston rings assembled in a plurality of ring grooves formed at predetermined intervals in the axial direction on the outer periphery of the piston,
Irradiate light in a direction inclined with respect to the piston radial direction from the side position of the piston toward the piston ring assembly position. In this light irradiation state, the piston is rotated around its axis to rotate around the outer circumferential surface. In addition to confirming the presence / absence of each piston ring and the circumferential position of each piston ring joint portion by photographing the image of the above from the piston side position, each piston ring joint portion is obtained by data processing of the photographed image. A method for inspecting a piston ring, comprising: determining whether the width of the piston ring is acceptable.   By rotating the piston against the piston outer peripheral surface from the side opposite to the light irradiation and camera photographing position during rotation of the piston, the outer peripheral surface portion on the light irradiation and camera photographing side of each piston ring is moved outward of the piston outer peripheral surface. The method for inspecting a piston ring according to claim 1, wherein an image of one round is taken out by projecting.   3. The piston ring inspection method according to claim 1, wherein a laser beam is used as the irradiation light. A piston ring inspection device assembled to a plurality of ring grooves formed at predetermined intervals in the axial direction on the outer periphery of the piston,
A light source that is disposed at a side position of the piston and that emits light in a direction inclined with respect to the piston radial direction toward the piston ring assembly position; a piston rotation mechanism that rotates the piston around its axis; and the piston And a means for displaying a pass / fail judgment screen for the width of each piston ring joint by data processing of the captured image. An inspection device for a piston ring.   At the side position of the piston opposite to the light beam irradiation and camera photographing position, the outer peripheral surface portion of the piston ring is irradiated with the light irradiation and camera photographing side of the piston ring by being pressed against the piston outer peripheral surface when the piston rotates. 5. A piston ring inspection device according to claim 4, wherein a ring pushing roller is provided to allow the ring to protrude outward. 6. The piston ring inspection device according to claim 4, wherein the light source is a laser.

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