WO2022080170A1 - Inspection method and inspection device for connecting rod - Google Patents

Abstract

In the inspection method and the inspection device for a connecting rod according to the present invention, an image for inspection (P) of a predetermined portion located on a major diameter pin hole (102a) side, including a joining portion (105), and viewed from the hole axial direction of the major diameter pin hole (102a) is acquired, a rod-side approximate circle (C1) conforming to a rod-side pin hole (102d) being a portion on a rod side in the major diameter pin hole (102a) is calculated from the image for inspection (P), a cap-side approximate circle (C2) conforming to a cap-side pin hole (102e) being a portion on a cap side in the major diameter pin hole (102a) is calculated from the image (P) for inspection, and the rod-side approximate circle (C1) and the cap-side approximate circle (C2) are used to determine whether or not the amount of a step of the joining portion (105) is larger than or equal to a predetermined threshold value.

Description

Connecting rod inspection method and inspection equipment

The technique disclosed herein is to divide the large end of an integrally molded connecting rod into a large end on the rod side and a large end on the cap side, and then split the large end on the rod side and the large end on the cap side. It belongs to the technical field related to an inspection method and an inspection device for a connecting rod for inspecting a step at a joint when rejoined.

Conventionally, in a connecting rod, which is an engine component, after integrally molding from a small end to a large end, the large end is split into a rod-side large end and a cap-side large end. There is. In the case of this manufacturing method, the large end portion on the rod side and the large end portion on the cap side, which are split and split, are recombined when assembled to the engine.

When the large end is broken and split, the residual stress is released and each broken part may be slightly deformed. Therefore, when the rod side large end portion and the cap side large end portion are recombined, a step may occur at the joint portion between the rod side large end portion and the cap side large end portion. If the amount of step at the joint exceeds a predetermined tolerance, it should be excluded as a defective product.

In the past, the area around the joint was traced with the operator's finger or nail, and the pass / fail of the step was decided based on the degree of catching. However, it is not possible to make a quantitative evaluation only by the sense of the operator, and there is a possibility that a defect is judged more than necessary. Therefore, as in Patent Document 1, a quantitative inspection method has been proposed.

In the inspection method described in Patent Document 1, a laser beam is applied to a surface to be inspected in a vicinity including a connecting portion of a connecting rod, a distance from the irradiated surface is measured, and a plurality of surfaces to be inspected composed of curved surfaces are measured. The process of obtaining the reference data divided into the points of, the process of obtaining the shape data obtained by averaging the reference data, the process of setting a virtual line by a plurality of points extracted from the shape data, and the point where the step portion is detected. The process of setting another virtual line that passes through the reference point by moving the virtual line in parallel with the point that has returned to the previous position by a predetermined amount as the reference point, and proceeding by a predetermined amount from the point where the stepped portion is detected. The process of measuring the amount of movement in one dimension between another virtual line and the measurement point as the step amount of the step portion, and whether or not the measured step amount is within a predetermined range. It includes a step of determining the pass / fail of the connecting rod by.

Further, the inspection method described in Patent Document 1 determines the pass / fail of the connecting rod by detecting a step in the portion of the joint portion opposite to the pin hole at the large end.

Japanese Unexamined Patent Publication No. 2006-133188

However, in the inspection method described in Patent Document 1, in order to obtain shape data around the joint portion, it is necessary to irradiate a plurality of places on the surface to be inspected with laser light from a distance sensor to create averaging data, which is extremely difficult. It takes time. It is possible to shorten the inspection time by increasing the number of distance sensors, but it is inevitable that the inspection equipment will become larger.

Further, the most important part of the joint portion is the portion on the pin hole side where the crankpin is arranged, but in the inspection method described in Patent Document 1, it is possible to detect a step on the portion on the pin hole side in the joint portion. difficult.

The technique disclosed herein has been made in view of these points, and its purpose is to reconnect the connecting rods that have been broken and divided into the large end on the rod side and the large end on the cap side. The purpose is to efficiently and accurately inspect the amount of steps at the joint when the joint is formed.

In order to solve the above problems, in the technique disclosed here, the large end portion of the integrally molded connecting rod is split into a rod side large end portion and a cap side large end portion, and then the rod side large end portion is divided. For the inspection method of the connecting rod for inspecting the step of the joint portion when the portion and the cap side large end portion are recombined, the portion of the large end portion on the pin hole side and including the joint portion. An image acquisition step of acquiring an inspection image which is an image of a predetermined portion viewed from the hole axis direction of the pin hole, and a rod side which is a portion of the large end portion of the pin hole on the rod side from the inspection image. From the first approximate circle calculation step of calculating the rod side approximate circle along the pin hole and the inspection image, the cap along the cap side pin hole which is the portion of the cap side large end portion in the pin hole. Using the second approximate circle calculation step for calculating the side approximate circle and the rod side approximate circle and the cap side approximate circle, a step between the rod side pin hole and the cap side pin hole in the joint portion. The configuration includes a determination step of determining whether the amount is equal to or greater than a predetermined threshold.

According to this configuration, since the image of the predetermined part including the joint is used for the inspection, it does not take time to obtain the data necessary for the inspection. Further, since the pin hole at the large end is generally formed to have a predetermined roundness, the rod side pin hole and the cap side pin hole around the joint portion are basically a part of a circle. .. Therefore, calculating and comparing the rod-side approximate circle and the cap-side approximate circle reflects the actual shape as compared with the case where the shape around the joint portion is approximated by a straight line. Therefore, highly accurate inspection is possible.

In one embodiment of the connecting rod inspection method, the image acquisition step is a first inspection image in which the joint portion extends in the vertical direction of the image at the center of the horizontal direction of the image, or the inspection image. The step is a step of acquiring a second inspection image in which the joint portion extends in the horizontal direction of the image at the center in the vertical direction of the image, and the determination step is a step of acquiring the first inspection image when the inspection image is the first inspection image. When the vertical straight line extending in the vertical direction of the first inspection image and located in the center of the horizontal direction of the first inspection image is calculated, when the inspection image is the second inspection image, the above-mentioned A horizontal straight line extending in the horizontal direction of the second inspection image and located in the center of the vertical direction of the second inspection image is calculated, and is the intersection of the rod-side approximate circle and the vertical straight line or the horizontal straight line. An intersection calculation step for obtaining one intersection and a second intersection that is an intersection of the cap-side approximate circle and the vertical straight line or the horizontal straight line, and the distance between the first intersection and the second intersection are determined by the joint portion. The step amount includes a step amount determination step of determining whether the step amount is equal to or more than a predetermined threshold value.

According to this configuration, since the first intersection and the second intersection are located at the step portion of the joint portion or in the vicinity of the step portion, the distance between the first intersection point and the second intersection is equal to the step amount of the joint portion. Become. Thereby, the inspection accuracy can be further improved. Further, when calculating the vertical straight line and the horizontal straight line, it is not necessary to recognize the position of the joint portion. Therefore, the amount of steps at the joint can be calculated more efficiently.

In another embodiment of the connecting rod inspection method, at least one of the first and second approximate circle calculation steps is a step of calculating the rod side or cap side approximate circle centered on the center of the pin hole. Yes, in the determination step, the first intersection point, which is the intersection of the approximate circle centered on the center of the pin hole and the joint portion among the rod-side approximate circle and the cap-side approximate circle, is obtained, and the first. A normal line calculation step for calculating the normal line of one of the approximate circles passing through the intersection, a normal line calculated in the normal line calculation step, and the other approximate circle of the rod side approximate circle and the cap side approximate circle. The step amount is determined by using the distance between the first intersection and the second intersection as the step amount of the joint portion and the intersection calculation step for obtaining the second intersection, which is the intersection of the above. Includes a step amount determination step.

That is, in general, the joint portion is formed so as to extend in the radial direction of the pin hole at the large end portion. The normal extending from the approximate circle centered on the center of the pin hole coincides with the radial direction of the pin hole. Therefore, the normal extending from the intersection of one of the approximate circles and the joint portion extends in the extending direction of the joint portion. Therefore, by using each intersection of the normal and each approximate circle, the step amount can be calculated with high accuracy. Thereby, the inspection accuracy can be further improved.

Another aspect of the technique disclosed herein is to break and divide the large end of an integrally molded connecting rod into a rod-side large end and a cap-side large end, and then split the rod-side large end and the cap. The target is a connecting rod inspection device that inspects the step of the joint when it is recombined with the large end of the side. Specifically, the connecting rod is based on a camera that acquires an image of a predetermined portion including the joint portion and an inspection image that represents a portion of the image acquired by the camera on the pin hole side of the large end portion. The inspection unit includes an inspection unit for determining pass / fail, and the inspection unit includes a rod-side approximate circle along the rod-side pin hole which is a portion of the rod-side large end portion in the pin hole from the inspection image. A cap-side approximate circle along the cap-side pin hole, which is a portion of the cap-side large end portion in the pin hole, is calculated, and the joint portion is used by using the rod-side approximate circle and the cap-side approximate circle. The configuration is such that it is determined whether or not the amount of step between the rod-side pin hole and the cap-side pin hole in the above is equal to or greater than a predetermined threshold value.

According to this configuration, the inspection is performed using the image captured by the camera, so it does not take time to obtain the data required for the inspection. Further, since the amount of steps in the portion of the joint portion on the pin hole side is inspected by assuming an approximate circle of the rod side pin hole and the cap side pin hole, the inspection can be performed with high accuracy.

In the connecting rod inspection device, the connecting rod in a state where the rod-side large end portion and the cap-side large end portion are recombined, the hole axis of the pin hole at the large end portion is in the vertical direction. The camera is further provided with a stage to be mounted in such a manner, and the camera is arranged so that the optical axis is parallel to the hole axis with respect to the connecting rod mounted on the stage, and the connecting rod is placed on the upper side. It may be configured to take an image from.

According to this configuration, the connecting rod is placed on the stage so that the hole axis of the pin hole at the large end is in the vertical direction, so that the large end on the rod side and the large end on the cap side are the pin holes. It becomes difficult to shift in the radial direction. Further, since the optical axis of the camera is parallel to the hole axis of the pin hole, it is possible to accurately acquire an image of the stepped portion of the joint portion. As a result, the inspection accuracy can be further improved.

In one embodiment of the connecting rod inspection device, the camera is a first inspection image or a joint portion in which the joint portion extends in the vertical direction of the image in the horizontal center of the image as the inspection image. Acquires a second inspection image extending in the horizontal direction of the image at the center of the vertical direction of the image, and the inspection unit obtains the first inspection image when the inspection image is the first inspection image. A vertical straight line extending in the vertical direction of the image and located at the center in the horizontal direction of the first inspection image is calculated, and when the inspection image is the second inspection image, the second inspection image is calculated. A horizontal straight line extending in the horizontal direction and located at the center of the vertical direction of the second inspection image is calculated, and the first intersection, which is the intersection of the rod-side approximate circle and the vertical straight line or the horizontal straight line, and the above The intersection calculation process for obtaining the second intersection, which is the intersection of the cap-side approximate circle and the vertical straight line or the horizontal straight line, and the distance between the first intersection and the second intersection are used as the step amount of the joint portion. The step amount determination process for determining whether the step amount is equal to or greater than a predetermined threshold is executed.

In another embodiment of the connecting rod inspection device, the inspection unit has each approximate circle such that at least one of the rod-side or cap-side approximate circles is an approximate circle centered on the center of the pin hole. Further, the inspection unit obtains a first intersection point, which is an intersection of the approximate circle centered on the center of the pin hole and the joint portion among the rod-side approximate circle and the cap-side approximate circle. The normal line calculation process for calculating the normal line of the one approximate circle passing through the first intersection, the normal line calculated by the normal line calculation process, and the other of the rod side approximate circle and the cap side approximate circle. Whether the step amount is equal to or greater than a predetermined threshold value, with the intersection calculation process for obtaining the second intersection, which is the intersection with the approximate circle, and the distance between the first intersection and the second intersection as the step amount of the joint portion. The step amount determination process for determining is executed.

As described above, according to the technique disclosed here, the step amount of the connecting portion when the connecting rod split by fracture is recombined between the large end portion on the rod side and the large end portion on the cap side can be efficiently reduced. It can be inspected with high accuracy.

FIG. 1 is a front view of a connecting rod inspected by the inspection apparatus according to the first embodiment. FIG. 2 is a side view of the inspection device. FIG. 3 is a view of the inspection device from above. FIG. 4 is a block diagram showing a controller configuration. FIG. 5 is a diagram showing an image around the joint portion captured by the camera. FIG. 6 is a diagram illustrating an approximate circle on the cap side and an approximate circle on the rod side. FIG. 7 is a diagram in which vertical straight lines are arranged with respect to the image of FIG. FIG. 8 is a flowchart showing the processing operation of the inspection device. FIG. 9 is a diagram showing an inspection by the inspection apparatus according to the second embodiment, and shows a state in which the intersection of the cap-side approximate circle and the joint portion is calculated. FIG. 10 is a diagram showing a state in which a normal passing through the intersection of the cap-side approximate circle and the joint portion is calculated from the state of FIG. FIG. 11 is a flowchart showing the processing operation of the inspection device according to the second embodiment.

Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

<Connecting rod>
FIG. 1 shows a connecting rod 100 (hereinafter referred to as a connecting rod 100) as an inspection target and a piston 110 attached to the connecting rod 100. The connecting rod 100 connects the piston 110 and the crank shaft (not shown) in the engine, and is a load transmission member that constitutes a transmission path of the explosive load from the piston 110 to the crank shaft.

The connecting rod 100 has a small end portion 101 to which the piston 110 is attached, a large end portion 102 connected to the crank shaft, and a rod-shaped rod portion 103 connecting the small end portion 101 and the large end portion 102. A small diameter pin hole 101a is formed in the small end portion 101, and the piston 110 is attached to the connecting rod 100 via a piston pin (not shown) inserted into the small diameter pin hole 101a. A large-diameter pin hole 102a is formed in the large-diameter pin hole 102a, and the connecting rod 100 and the crank shaft are connected by inserting the crank pin of the crank shaft into the large-diameter pin hole 102a. The large end 102 is divided into a rod-side large end 102b on the rod portion 103 side and a cap-side large end 102c on the opposite side of the rod portion 103. The large end 102 is integrated by abutting the large end 102b on the rod side and the large end 102c on the cap side and fastening and fixing both of them with two bolts 104.

In the first embodiment, the connecting rod 100 is a so-called split connecting rod. Specifically, the large end 102 of the connecting rod 100 is integrally formed so that the large diameter pin hole 102a is formed, and then is broken and divided into a rod side large end 102b and a cap side large end 102c. When the engine is arranged in the engine, the large end portion 102b on the rod side and the large end portion 102c on the cap side are arranged so that the crank shaft of the engine is located in the large diameter pin hole 102a. Then, the fracture surface of the large end portion 102b on the rod side and the fracture surface of the large end portion 102c on the cap side are butted against each other, and the large end portion 102b on the rod side and the large end portion 102c on the cap side are fastened and fixed by two bolts 104. Is integrated with. The boundary between the large end portion 102b on the rod side and the large end portion 102c on the cap side (that is, the connecting portion 105) is formed so as to extend in the radial direction of the large diameter pin hole 102a.

In the case of such a split connecting rod, when the large end 102 is fractured and split, the residual stress is released and the rod side large end 102b and the cap side large end 102c may be deformed. In particular, the cap-side large end portion 102c has a smaller volume than the rod-side large end portion 102b to which the rod portion 103 is connected, so that the cap-side large end portion 102c is liable to bend and deform. When the rod-side large end portion 102b and the cap-side large end portion 102c are deformed, a step (see FIG. 5 and the like) is formed at the joint portion 105 between the rod-side large end portion 102b and the cap-side large end portion 102c. The amount of steps in the coupling portion 105, particularly the portion of the rod-side large end portion 102b in the large-diameter pin hole 102a in the pin hole-side coupling portion 105a (see FIG. 5 and the like) which is the portion of the coupling portion 105 on the large-diameter pin hole 102a side. When the amount of step between the rod-side pin hole 102d (hereinafter referred to as the rod-side pin hole 102d) and the cap-side large end portion 102c of the large-diameter pin hole 102a (hereinafter referred to as the cap-side pin hole 102e) exceeds a predetermined tolerance. In some cases, the smooth interlocking of the piston 110 and the crank shaft is adversely affected, so it is necessary to exclude them as defective products. Conventionally, the pass / fail of a step has been determined based on the degree of catching by tracing the periphery of the joint portion 105 with a worker's finger or nail. However, it is not possible to make a quantitative evaluation only by the sense of the operator, and there is a possibility that a defect is judged more than necessary.

Therefore, in the first embodiment, the inspection method is devised so that the step amount of the joint portion 105 can be inspected efficiently and accurately. Hereinafter, the inspection device 1 according to the first embodiment will be described with reference to FIGS. 2 to 7.

<Inspection equipment>
2 and 3 schematically show the inspection device 1. This inspection device 1 obtains the step amount of the joint portion 105 by using the image data around the joint portion 105.

The inspection device 1 has a base 2, a conveyor 3 provided on the base 2, and a stage 10 mounted on the conveyor 3 and on which the connecting rod 100 is placed. Further, the inspection device 1 has a camera 20 arranged on the ceiling 5 facing the base 2 and a lighting device 21 arranged around the camera 20. Further, the inspection device 1 has a display device 60 for displaying the inspection result.

On the stage 10, the connecting rod 100 in a state where the large end portion 102b on the rod side and the large end portion 102c on the cap side are recombined is placed so that the hole axis of the large diameter pin hole 102a is in the vertical direction. The stage 10 has a plurality of pins 11 for positioning the connecting rod 100. As shown in FIG. 3, the plurality of pins 11 include one first pin 11a inserted into the small diameter pin hole 101a and three second pins 11b inserted into the large diameter pin hole 102a. The first and second pins 11a and 11b are respectively arranged on the stage 10 so that the connecting portion 105 is located on the optical axis of the camera 20 when the connecting rod 100 is located directly under the camera 20. .. Specifically, each of the second pins 11b is arranged at a position so as to pass directly under the camera 20 when the conveyor 3 is operated and the stage 10 is moved, and the first pins 11a are arranged. The connecting portion 105 is arranged so that the extending direction is substantially parallel to the conveying direction of the conveyor 3.

The camera 20 is arranged facing downward so as to take an image of the connecting rod 100 placed on the stage 10 from above. The camera 20 is arranged so that its optical axis is parallel to the hole axis of the large-diameter pin hole 102a. As shown in FIGS. 5 to 7, the camera 20 is a camera having a resolution such that the periphery of the pin hole side coupling portion 105a can be magnified and imaged. The camera 20 includes an IR (Infrared) camera, a CCD (Charge Coupled Device) camera, a CMOS (Complementary Metal Oxide Semiconductor) camera, a line sensor camera, and the like.

Four lighting devices 21 are provided so as to surround the camera 20. The four lighting devices 21 are configured to be capable of irradiating light having different wavelengths such as white light, red light, and blue light in a single color or in combination. The angle of incidence of the light emitted by each illuminating device 21 on the coupling portion 105 and the amount of light are independently adjusted by the controller 50. That is, the controller 50 may operate only a part of the lighting devices 21 and stop the other lighting devices 21, or operate all the lighting devices 21 and make the light amount of each lighting device 21 different. can. The lighting device 21 is composed of an LED light and a fluorescent lamp, respectively. The number and arrangement of the lighting devices 21 are not particularly limited.

The display device 60 is, for example, a display provided in a computer. The display device 60 may be integrally configured with the controller 50 described later.

<Control system>
The inspection device 1 has a controller 50 that controls a camera 20 and the like. The controller 50 has a processor having a CPU, a memory in which a plurality of modules are stored, and the like. The controller 50 has a function of obtaining the step amount of the pin hole side coupling portion 105a based on the image captured by the camera 20 and determining the pass / fail of the connecting rod 100 based on the step amount. Such a function is stored as software in a module of memory, and is exerted by the processor executing such software. The number of processors and memories is not limited to one, and the controller 50 may have two or more processors and memories.

As shown in FIG. 4, the controller 50 includes an optical system control unit 51, a preprocessing unit 52, an inspection unit 53, a display control unit 54, and a transfer control unit 55. The optical system control unit 51, the pretreatment unit 52, the inspection unit 53, the display control unit 54, and the transport control unit 55 are examples of the modules, respectively. The optical system control unit 51 and the like shown in FIG. 4 are a part of the configuration of the controller 50, and do not exclude that the controller 50 has other functions. Further, these functions may be configured in different modules or may be stored in one module.

The optical system control unit 51 adjusts the enlargement and reduction of the area imaged by the camera 20, and adjusts the incident angle of light of each lighting device 21, the color of light, the amount of light, and the like. The camera 20 acquires the image data of the coupling unit 105 according to the control signal from the optical system control unit 51. The optical system control unit 51 controls the camera 20 and each lighting device 21 so as to acquire an inspection image P (see FIG. 5) which is an enlarged image of a predetermined portion including each pin hole side coupling portion 105a.

The pre-processing unit 52 performs pre-processing such as shading correction, dark level correction, bit compression, and coordinate setting on the image data acquired by the camera 20.

The inspection unit 53 performs a process for measuring the step amount of the step generated in the pin hole side coupling portion 105a with respect to the two-dimensional image data of the pin hole side coupling portion 105a acquired by the camera 20. Specifically, from the inspection image P, the inspection unit 53 has a rod-side approximate circle C1 (see FIG. 6 and the like) along the rod-side pin hole 102d and a cap-side approximation along the cap-side pin hole 102e. Calculate the circle C2 (see FIG. 6 etc.). From this, the inspection unit 53 corresponds to the approximate circle calculation unit.

Further, the inspection unit 53 calculates the step amount of the step generated in the pin hole side joint portion 105a by using the calculated rod side and cap side approximate circles C1 and C2. Then, the inspection unit 53 determines the pass / fail of the connecting rod 100 from the calculated step amount.

The display control unit 54 outputs a control signal to the display device 60 so as to display the determination result of the inspection unit 53. When the inspection unit 53 determines that the inspection unit 53 has failed, the display control unit 54 causes the display device 60 to display the portion determined to be rejected.

The transport control unit 55 is configured to control the operation of the conveyor 3. The conveyor control unit 55 adjusts the conveyor speed of the stage 10 and temporarily stops the conveyor 3 when the camera 20 cannot acquire an image.

<test>
Next, with reference to FIGS. 5 to 7, the inspection regarding the step of the pin hole side coupling portion 105a by the inspection device 1 will be described. Since the connecting rod 100 always has a pair of pin hole side coupling portions 105a, the inspection by the inspection device 1 is performed for each of the pin hole side coupling portions 105a. In the following description, the inspection for one pin hole side coupling portion 105a will be described.

In the inspection, first, the inspection image P is acquired by the camera 20. As shown in FIG. 5, the inspection image P is an image captured so that the pin hole side coupling portion 105a extends in the vertical direction of the image at the center in the horizontal direction of the image. Further, the inspection image P is an image including a portion near the pin hole side coupling portion 105a of the rod side pin hole 102d and a portion near the pin hole side coupling portion 105a of the cap side pin hole 102e, respectively. The inspection image P includes the rod side pin hole 102d and the cap side pin hole 102e to the extent that the rod side approximate circle C1 and the cap side approximate circle C2 can be calculated. Specifically, the inspection image P includes a range of ± 4 to 5 mm when the pin hole side coupling portion 105a is centered, the rod side is the − side, and the cap side is the + side.

When the inspection image P is acquired by the camera 20, as shown in FIG. 6, the inspection unit 53 calculates the rod-side and cap-side approximate circles C1 and C2 from the inspection image P. The inspection unit 53 calculates the rod-side approximate circle C1 from the portion of the rod-side pin hole 102d in the inspection image P, and calculates the cap-side approximate circle C2 from the portion of the cap-side pin hole 102e in the inspection image P. .. In the first embodiment, the center of the rod-side approximate circle C1 and the center of the cap-side approximate circle C2 do not necessarily have to coincide with each other.

After calculating the rod-side and cap-side approximate circles C1 and C2, the inspection unit 53 extends in the vertical direction of the inspection image P and is located in the center of the horizontal direction of the inspection image P as shown in FIG. 7. Calculate the straight line VL. The vertical straight line VL does not necessarily have to pass through the stepped portion of the pin hole side coupling portion 105a. Since the inspection image P is imaged so that the pin hole side coupling portion 105a extends in the vertical direction at the center of the horizontal direction of the image, the vertical straight line VL does not pass through the step portion of the pin hole side coupling portion 105a. Even so, the vertical straight line VL is located very close to the stepped portion. Further, the vertical straight line VL is in a state of extending along the pin hole side coupling portion 105a. Therefore, even if the vertical straight line VL does not pass through the stepped portion of the pin hole side coupling portion 105a, there is almost no problem in calculating the step amount of the pin hole side coupling portion 105a.

Next, as shown in FIG. 7, the inspection unit 53 has a cap, which is the intersection of the rod-side approximate circle C1 and the vertical straight line VL, the rod-side intersection CP11, and the cap-side approximate circle C2, which is the intersection of the vertical straight line VL. Find the side intersection CP12, respectively. The rod-side intersection CP11 referred to here corresponds to the first intersection of claims 2 and 6, and the cap-side intersection CP12 corresponds to the second intersection of claims 2 and 6.

Then, the inspection unit 53 calculates the step amount of each of the pair of pin hole side coupling portions 105a, and determines whether or not the step amount is equal to or more than a predetermined threshold value. The inspection unit 53 calculates the distance between the rod-side intersection CP11 and the cap-side intersection CP12, and uses the calculated distance as the step amount of the pin hole-side coupling portion 105a. The inspection unit 53 determines that the connecting rod 100 to be inspected has failed when it is determined that the step amount is equal to or greater than a predetermined threshold value in at least one of the pin hole side coupling portions 105a. The inspection unit 53 determines that the connecting rod 100 to be inspected has passed when it is determined that the step amount is less than a predetermined threshold value in both the pin hole side coupling portions 105a. When the step amount in one pin hole side coupling portion 105a is equal to or greater than a predetermined threshold value, the inspection unit 53 does not inspect the step amount in the other pin hole side coupling portion 105a, and the connecting rod to be inspected. 100 may be determined to be unacceptable. The predetermined threshold value is a step amount that affects the interlocking of the crank shaft and the piston, and can be arbitrarily set by the operator.

In this way, by calculating the step amount from the intersections CP11 and CP12 between the vertical straight line VL and the approximate circles C1 and C2 on the rod side and the cap side, the step amount can be calculated without being affected by the uneven shape of the step portion. can. That is, as shown in FIGS. 5 to 7, when the step portion is uneven, the step amount is calculated from the intersection of the rod-side and cap-side approximate circles C1 and C2 and the step portion, and the actual step amount is calculated. Will be calculated large. If a vertical straight line VL that extends along the pin hole side coupling portion 105a as in the first embodiment is used, the influence of the uneven shape of the step portion is suppressed, so that the step amount can be calculated accurately. ..

<flowchart>
Next, a flowchart for inspecting the step amount by the inspection device 1 will be described with reference to FIG. The flowchart shown in FIG. 8 is based on the premise that the connecting rod 100 is placed on the stage 10.

In step S101, the controller 50 operates the conveyor 3 to convey the connecting rod 100.

Next, in step S102, the controller 50 acquires the inspection image P of the coupling portion 105, particularly the pin hole side coupling portion 105a, by the camera 20.

Next, in step S103, the controller 50 calculates the rod-side approximate circle C1 and the cap-side approximate circle C2 from the acquired inspection image P.

Next, in step S104, the controller 50 calculates the vertical straight line VL with respect to the inspection image P.

Subsequently, in step S105, the controller 50 determines the rod-side intersection CP11, which is the intersection of the rod-side approximate circle C1 and the vertical straight line VL, and the cap-side intersection CP12, which is the intersection of the cap-side approximate circle C2 and the vertical straight line VL. calculate.

Next, in step S106, the controller 50 calculates the step amount of the pin hole side coupling portion 105a by calculating the distance between the rod side intersection point CP11 and the cap side intersection point CP12.

Next, in step S107, the controller 50 determines whether or not the step amount calculated in step S106 is equal to or greater than a predetermined threshold value. When YES, the step amount is equal to or greater than a predetermined threshold value, the controller 50 proceeds to step S108. When the step amount is NO, which is less than a predetermined threshold value, the controller 50 proceeds to step S109.

In step S108, the controller 50 determines that the inspected connecting rod 100 has failed. After step S108, it returns.

On the other hand, in step S109, the controller 50 determines whether or not both inspections of the pair of pin hole side coupling portions 105a have been completed. When the inspection of both of the pair of pin hole side coupling portions 105a is completed, the controller 50 proceeds to step S110. On the other hand, when the inspection of only one of the pair of pin hole side coupling portions 105a is completed and the inspection of the other is not completed, the controller 50 returns to step S101 and also the other pin hole side coupling portion 105a. Inspect the amount of steps.

In step S110, the controller 50 determines that the inspected connecting rod 100 has passed. After step S110, it returns.

Therefore, the inspection device 1 of the conrod 100 according to the first embodiment acquires an inspection image P which is an image of a predetermined portion including the pin hole side coupling portion 105a viewed from the hole axis direction of the large diameter pin hole 102a. (Step S102), from the inspection image P, a rod-side approximate circle C1 along the rod-side pin hole 102d, which is a portion of the rod-side large end portion 102b in the large-diameter pin hole 102a, is calculated (step S103) and inspected. From the image P, a cap-side approximate circle C2 along the cap-side pin hole 102e, which is a portion of the cap-side large end 102c in the large-diameter pin hole 102a, is calculated (step S103), and the rod-side approximate circle C1 is obtained. Using the cap-side approximate circle C2, it is determined whether or not the step amount between the rod-side pin hole 102d and the cap-side pin hole 102e in the pin hole-side coupling portion 105a is equal to or greater than a predetermined threshold value (steps S104 to S107). ). As a result, the inspection image P required for the inspection can be an image of a predetermined portion including the pin hole side coupling portion 105a, so that it does not take time to obtain the data necessary for the inspection and the efficiency is high. Further, since the large diameter pin hole 102a is generally formed to have a predetermined roundness, the rod side pin hole 102d and the cap side pin hole 102e around the pin hole side coupling portion 105a are basically formed. It is a part of a circle. Therefore, calculating and comparing the rod-side approximate circle C1 and the cap-side approximate circle C2 reflects the actual shape as compared with the case where the shape around the joint portion 105 is approximated by a straight line. .. Therefore, highly accurate inspection is possible.

Further, in the inspection device 1 according to the first embodiment, it is possible to calculate the step amount of the pin hole side coupling portion 105a which is a portion of the coupling portion 105 on the large diameter pin hole 102a side. That is, the step on the large-diameter pin hole 102a side where the crankpin is arranged has a greater influence on the engine than the step on the side opposite to the large-diameter pin hole 102a. Therefore, in the inspection device 1 according to the first embodiment, high quality inspection is possible by calculating the step amount of the pin hole side coupling portion 105a.

Further, in the first embodiment, the inspection image P is an image in which the pin hole side joint portion 105a extends in the vertical direction of the image at the center in the horizontal direction of the image, and the inspection is performed in the vertical direction of the inspection image P. A vertical straight line VL that extends and is located in the center of the inspection image P in the horizontal direction is calculated, and the rod side intersection point CP11, which is the intersection of the rod side approximate circle C1 and the vertical straight line VL, and the cap side approximate circle C2 and the vertical direction. The cap-side intersection CP12, which is the intersection with the straight line VL, is obtained, and the distance between the rod-side intersection CP11 and the cap-side intersection CP12 is used as the step amount of the coupling portion 105 to determine whether the step amount is equal to or greater than a predetermined threshold value. It is executed by doing. That is, since the rod-side intersection CP11 and the cap-side intersection CP12 are located at the step portion of the pin hole-side joint portion 105a or in the vicinity of the step portion, the distance between the rod-side intersection CP11 and the cap-side intersection CP12 is the pin hole side. The value is equal to the step amount of the joint portion 105a. Thereby, the inspection accuracy can be further improved. Further, when the vertical straight line VL is applied to the image, it is not necessary to recognize the position of the pin hole side coupling portion 105a. Therefore, the inspection can be performed mechanically by a computer, and the step amount of the joint portion 105 can be efficiently calculated.

Further, in the inspection device 1 according to the first embodiment, the connecting rod 100 in a state where the rod-side large end portion 102b and the cap-side large end portion 102c are recombined is provided with the hole axis of the large-diameter pin hole 102a in the vertical direction. The camera 20 of the inspection device 1 is arranged so that the optical axis of the connecting rod 100 arranged on the stage 10 is parallel to the hole axis of the large-diameter pin hole 102a. At the same time, the connecting rod 100 is imaged from above. As a result, the connecting rod 100 is placed on the stage 10 so that the hole axis of the large diameter pin hole 102a is in the vertical direction, so that the large diameter pin 102b on the rod side and the large end 102c on the cap side are placed on the large diameter pin. It becomes difficult to shift in the radial direction of the hole 102a. Further, since the optical axis of the camera 20 is parallel to the hole axis of the large-diameter pin hole 102a, it is possible to accurately capture a two-dimensional image around the pin hole side coupling portion 105a. As a result, the inspection image P can be acquired with high accuracy. As a result, the inspection accuracy can be further improved.

(Embodiment 2)
Hereinafter, the second embodiment will be described in detail with reference to the drawings. In the following description, the parts common to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the second embodiment, the method of calculating the step amount of the pin hole side coupling portion 105a is different from that of the first embodiment. Since the configuration of the inspection device 1 is the same as the configuration of the first embodiment, detailed description thereof will be omitted.

The method of calculating the step amount of the pin hole side coupling portion 105a in the second embodiment will be described with reference to FIGS. 9 and 10.

As shown in FIG. 9, the inspection unit 53 calculates the rod-side approximate circle C1 and the cap-side approximate circle C2. At this time, the inspection unit 53 calculates an approximate circle as the cap-side approximate circle C2, which is the center AP of the large-diameter pin hole 102a and along the cap-side pin hole 102e. The rod-side approximate circle C1 does not have to be centered on the center AP of the large-diameter pin hole 102a.

Next, the inspection unit 53 applies the rod-side approximate circle C1 and the cap-side approximate circle C2 to the inspection image P, respectively. The inspection unit 53 calculates the cap-side intersection CP22 between the stepped portion of the pin hole-side coupling portion 105a and the cap-side pin hole 102e. The cap-side intersection CP22 referred to here corresponds to the first intersection of claims 3 and 7.

Next, the inspection unit 53 calculates the normal NL of the cap-side approximate circle C2 passing through the intersection CP22. Since the cap-side approximate circle C2 is centered on the center AP of the large-diameter pin hole 102a, the normal NL extends in the radial direction of the large-diameter pin hole 102a. As described in the first embodiment, since the coupling portion 105 is basically formed so as to extend in the radial direction of the large diameter pin hole 102a, the extension direction of the normal NL is the coupling portion 105 (pin in FIG. 10). It substantially coincides with the extending direction of the hole-side joint portion 105a).

Subsequently, the inspection unit 53 calculates the rod-side intersection CP21, which is the intersection of the normal NL and the rod-side approximate circle C1. The rod-side intersection CP21 referred to here corresponds to the second intersection of claims 3 and 7.

Then, the inspection unit 53 calculates the step amount of each of the pair of pin hole side coupling portions 105a, and determines whether or not the step amount is equal to or more than a predetermined threshold value. The inspection unit 53 calculates the distance between the rod-side intersection CP21 and the cap-side intersection CP22, and uses the calculated distance as the step amount of the pin hole-side coupling portion 105a. After that, the inspection unit 53 makes a pass / fail judgment of the connecting rod 100 based on the judgment result of whether or not the step amount is equal to or more than a predetermined threshold value. Since the method of pass / fail determination by the inspection unit 53 is the same as that of the first embodiment, detailed description thereof will be omitted.

Next, the flowchart of the step amount inspection according to the second embodiment will be described with reference to FIG. The flowchart shown in FIG. 11 is based on the premise that the connecting rod 100 is placed on the stage 10.

In step S201, the controller 50 operates the conveyor 3 to convey the connecting rod 100.

Next, in step S202, the controller 50 acquires the inspection image P of the coupling portion 105, particularly the pin hole side coupling portion 105a, by the camera 20.

Next, in step S203, the controller 50 calculates the rod-side approximate circle C1 and the cap-side approximate circle C2 from the acquired inspection image P. The controller 50 calculates an approximate circle centered on the center AP of the large-diameter pin hole 102a for the cap-side approximate circle C2.

Next, in step S204, the controller 50 calculates the cap-side intersection point CP22, which is the intersection of the cap-side approximate circle C2 and the stepped portion of the pin hole-side joint portion 105a.

Subsequently, in step S205, the controller 50 calculates the normal NL passing through the cap-side intersection CP22.

Next, in step S206, the controller 50 calculates the rod-side intersection CP21, which is the intersection of the normal NL and the rod-side approximate circle C1.

Next, in step S207, the controller 50 calculates the step amount of the pin hole side coupling portion 105a by calculating the distance between the rod side intersection point CP21 and the cap side intersection point CP22.

Subsequently, in step S208, the controller 50 determines whether or not the step amount calculated in step S207 is equal to or greater than a predetermined threshold value. When YES, the step amount is equal to or greater than a predetermined threshold value, the controller 50 proceeds to step S209. When the step amount is NO, which is less than a predetermined threshold value, the controller 50 proceeds to step S210.

In step S209, the controller 50 determines that the inspected connecting rod 100 has failed. After step S209, it returns.

On the other hand, in step S210, the controller 50 determines whether or not both inspections of the pair of pin hole side coupling portions 105a have been completed. When the inspection of both of the pair of pin hole side coupling portions 105a is completed, the controller 50 proceeds to step S211. On the other hand, when the inspection of only one of the pair of pin hole side coupling portions 105a is completed and the inspection of the other is not completed, the controller 50 returns to step S201 and also the other pin hole side coupling portion 105a. Perform an inspection.

In step S211 above, the controller 50 determines that the inspected connecting rod 100 has passed. After step S211 it returns.

Therefore, according to the configuration of the second embodiment, as the cap-side approximate circle C2, a circle centered on the center AP of the large-diameter pin hole 102a is calculated, and the cap-side approximate circle C2 and the pin hole-side coupling portion 105a are combined. The cap-side intersection CP22, which is the intersection, is obtained, the normal NL of the cap-side approximate circle C2 passing through the cap-side intersection CP22 is calculated, and the rod-side intersection CP21, which is the intersection of the normal NL and the rod-side approximate circle C1,. Is obtained, and the distance between the cap side intersection CP22 and the rod side intersection CP21 is used as the step amount of the pin hole side coupling portion 105a, and it is determined whether the step amount is equal to or larger than a predetermined threshold value. Also in this method, the influence of the uneven shape formed on the pin hole side joint portion 105a can be suppressed, and the step amount of the pin hole side joint portion 105a can be calculated accurately.

(Other embodiments)
The technique disclosed herein is not limited to the above-described embodiment, and can be substituted as long as it does not deviate from the gist of the claims.

For example, in the above-described first and second embodiments, the vertical straight line VL and the normal line NL are calculated, and the step amount is calculated from the intersection of the vertical straight line VL and the normal line NL and the approximate circles C1 and C2. Not limited to this, for example, with the center of the rod-side approximate circle C1 and the center of the cap-side approximate circle C2 aligned, each approximate circle C1 and C2 are calculated, and the radius and cap of the rod-side approximate circle C1 are calculated. The difference from the radius of the side approximate circle C2 may be used as the step amount. As long as the centers are aligned, the difference in radius is caused by the step, so the difference in radius can be regarded as the amount of step.

Further, after calculating the rod-side approximate circle C1 and the cap-side approximate circle C2, the operator arbitrarily sets a straight line along the pin hole-side joint portion 105a, and the straight line and the approximate circles C1 and C2 are combined. The step amount of the pin hole side coupling portion 105a may be calculated from the intersection of the above.

Further, in the above-described first embodiment, the inspection image P is an image in which the pin hole side joint portion 105a extends in the vertical direction of the image at the center in the horizontal direction of the image. Not limited to this, the inspection image P may be an image in which the pin hole side coupling portion 105a extends in the horizontal direction of the image at the center in the vertical direction of the image. At this time, the inspection unit 53 calculates a horizontal straight line extending in the horizontal direction of the inspection image P and located at the center of the vertical direction of the inspection image P, and the horizontal straight line and the rod-side and cap-side approximate circles. By calculating each intersection with C1 and C2, the step amount of the pin hole side coupling portion 105a is calculated.

Further, in the above-described second embodiment, the inspection unit 53 calculates a normal extending from the intersection of the cap-side approximate circle C2 and the stepped portion of the pin hole-side coupling portion 105a. Not limited to this, the inspection unit 53 may calculate a normal extending from the intersection of the rod-side approximate circle C1 and the stepped portion of the pin hole-side coupling portion 105a. The inspection unit 53 or the operator determines the normal from the shape of the pin hole side joint portion 105a based on the intersection of either the rod side approximate circle C1 or the cap side approximate circle C2 and the step portion of the pin hole side joint portion 105a. It may be possible to select whether to calculate.

The above-described embodiment is merely an example, and the scope of the present disclosure should not be construed in a limited manner. The scope of the present disclosure is defined by the scope of claims, and all modifications and changes belonging to the equivalent scope of the scope of claims are within the scope of the present disclosure.

The technique disclosed herein is to split the large end of an integrally molded connecting rod into a large end on the rod side and a large end on the cap side, and then split the large end on the rod side and the large end on the cap side. It is useful as a connecting rod inspection method for inspecting the step of the joint when rejoined.

1 Inspection device 4 Stage 20 Camera 53 Inspection unit 100 Connecting rod 102 Large end 102a Large diameter pin hole (pin hole at large end)
102b Rod side large end 102c Cap side large end 102d Rod side pin hole 102e Cap side pin hole 105 Coupling part 105a Pin hole side joint part (Pin hole side part in the joint part)

Claims (7)

After breaking and dividing the large end of the integrally molded connecting rod into the large end on the rod side and the large end on the cap side, the connection when the large end on the rod side and the large end on the cap side are recombined. It is an inspection method for connecting rods that inspects steps in the part.
An image acquisition step of acquiring an inspection image which is an image of a predetermined portion which is a portion on the pin hole side of the large end portion and includes the joint portion and is viewed from the hole axis direction of the pin hole.
A first approximate circle calculation step for calculating a rod-side approximate circle along the rod-side pin hole, which is a portion of the rod-side large end portion of the pin hole, from the inspection image.
A second approximate circle calculation step for calculating a cap-side approximate circle along the cap-side pin hole, which is a portion of the cap-side large end portion of the pin hole, from the inspection image.
A determination step of determining whether or not the amount of steps between the rod-side pin hole and the cap-side pin hole at the joint portion is equal to or greater than a predetermined threshold value by using the rod-side approximate circle and the cap-side approximate circle. A method for inspecting connecting rods, which comprises. In the connecting rod inspection method according to claim 1,
In the image acquisition step, as the inspection image, the first inspection image in which the joint portion extends in the vertical direction of the image in the horizontal center of the image, or the joint portion of the image in the vertical center of the image. It is a process of acquiring a second inspection image extending in the lateral direction.
The determination step is
When the inspection image is the first inspection image, a vertical straight line extending in the vertical direction of the first inspection image and located at the center in the horizontal direction of the first inspection image is calculated, while the above-mentioned When the inspection image is the second inspection image, a horizontal straight line extending in the horizontal direction of the second inspection image and located at the center of the vertical direction of the second inspection image is calculated, and the rod side is calculated. An intersection calculation step for obtaining a first intersection that is an intersection of an approximate circle and the vertical straight line or the horizontal straight line, and a second intersection that is an intersection of the cap-side approximate circle and the vertical straight line or the horizontal straight line.
A step amount determination step of determining whether or not the step amount is equal to or more than a predetermined threshold value, with the distance between the first intersection and the second intersection as the step amount of the joint portion.
A method for inspecting a connecting rod, which comprises. In the connecting rod inspection method according to claim 1,
At least one of the first and second approximate circle calculation steps is a step of calculating the rod-side or cap-side approximate circle centered on the center of the pin hole.
The determination step is
Of the rod-side approximate circle and the cap-side approximate circle, the first intersection, which is the intersection of the approximate circle centered on the center of the pin hole and the joint portion, is obtained, and one of the approximations passing through the first intersection is obtained. The normal line calculation process for calculating the normal line of a circle, and
An intersection calculation step for obtaining a second intersection, which is an intersection of the normal calculated in the normal calculation step and the other approximate circle of the rod-side approximate circle and the cap-side approximate circle.
A step amount determination step of determining whether or not the step amount is equal to or more than a predetermined threshold value, with the distance between the first intersection and the second intersection as the step amount of the joint portion.
A method for inspecting a connecting rod, which comprises. After breaking and dividing the large end of the integrally molded connecting rod into the large end on the rod side and the large end on the cap side, the connection when the large end on the rod side and the large end on the cap side are recombined. It is a connecting rod inspection device that inspects the step of the part.
A camera that acquires an image of a predetermined portion including the joint portion, and
An inspection unit for determining the pass / fail of the connecting rod based on an inspection image showing a portion of the image acquired by the camera on the pin hole side of the large end portion is provided.
From the inspection image, the inspection portion includes a rod-side approximate circle along the rod-side pin hole, which is a portion of the rod-side large end portion in the pin hole, and a portion of the cap-side large end portion in the pin hole. The cap-side approximate circle along the cap-side pin hole is calculated, and the rod-side approximate circle and the cap-side approximate circle are used to obtain the rod-side pin hole and the cap-side pin hole at the joint portion. An inspection device for a connecting rod, characterized in that it is determined whether or not the amount of steps between the two and the above is equal to or greater than a predetermined threshold value. In the connecting rod inspection device according to claim 4,
Further, a stage is provided on which the connecting rod in a state where the rod-side large end portion and the cap-side large end portion are recombined is placed so that the hole axis of the pin hole at the large end portion is in the vertical direction. Prepare,
The camera is arranged so that the optical axis is parallel to the hole axis with respect to the connecting rod mounted on the stage, and the connecting rod is imaged from above. Inspection equipment. In the connecting rod inspection device according to claim 4 or 5.
As the inspection image, the camera is a first inspection image in which the joint portion extends in the vertical direction of the image in the horizontal center of the image, or the joint portion is in the horizontal direction of the image in the vertical center of the image. Obtained the second inspection image extended to
The inspection unit
When the inspection image is the first inspection image, a vertical straight line extending in the vertical direction of the first inspection image and located at the center in the horizontal direction of the first inspection image is calculated, while the above-mentioned When the inspection image is the second inspection image, a horizontal straight line extending in the horizontal direction of the second inspection image and located at the center of the vertical direction of the second inspection image is calculated, and the rod side is calculated. An intersection calculation process for finding the first intersection, which is the intersection of the approximate circle and the vertical straight line or the horizontal straight line, and the second intersection, which is the intersection of the cap-side approximate circle and the vertical straight line or the horizontal straight line.
The step amount determination process for determining whether or not the step amount is equal to or more than a predetermined threshold value, with the distance between the first intersection and the second intersection as the step amount of the joint portion.
A connecting rod inspection device characterized by performing. In the connecting rod inspection device according to claim 4 or 5.
The inspection unit calculates each approximate circle so that at least one of the rod-side or cap-side approximate circles is an approximate circle centered on the center of the pin hole.
Furthermore, the inspection unit
Of the rod-side approximate circle and the cap-side approximate circle, the first intersection, which is the intersection of the approximate circle centered on the center of the pin hole and the joint portion, is obtained, and one of the approximations passing through the first intersection is obtained. The normal line calculation process that calculates the normal line of the circle, and
An intersection calculation process for obtaining a second intersection, which is an intersection of the normal calculated by the normal calculation process and the other approximate circle of the rod-side approximate circle and the cap-side approximate circle.
The step amount determination process for determining whether or not the step amount is equal to or more than a predetermined threshold value, with the distance between the first intersection and the second intersection as the step amount of the joint portion.
A connecting rod inspection device characterized by performing.

Images