JP2016003996A - Method and device for inspecting appearance of cylindrical body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for inspecting appearance, capable of inspecting a cylindrical body in the circumferential direction with a few cameras without exception.SOLUTION: A device for inspecting the appearance of a cylindrical body includes: a camera 10 for photographing a cylindrical body C while rotating around the cylindrical body C; lighting devices 11a, 11b which light up the cylindrical body while rotating around the cylindrical body C; and a lifting device 2 which, while fixing a positional relationship between the camera 10 and the lighting devices 11a, 11b, changes these rotation radii. Based on the photographed image, appearance is determined.

Description

  The present invention relates to a cylindrical body appearance inspection method and an appearance inspection apparatus.

  As an appearance inspection method for a long cylindrical body such as a rubber hose, as shown in Patent Document 1, each position in a direction perpendicular to the central axis of the cylindrical body is obtained from imaging data obtained by imaging the cylindrical body. There is a method of extracting height data at and detecting defects based on this data. This method has a problem in that defects having little unevenness such as small scratches cannot be detected.

  On the other hand, as shown in Patent Document 2, there is a method of detecting a defect by photographing a cylindrical body with a camera and processing the obtained image. With this method, it is possible to detect a defect having no unevenness.

JP 2010-197107 A JP 2008-26254 A

  However, in these methods, it is necessary to arrange a plurality of cameras around the cylindrical body in order to inspect the surface of the cylindrical body in the circumferential direction without omission. And the equipment introduction cost becomes higher by the number of cameras.

  Then, this invention makes it a subject to provide the external appearance inspection method and external appearance inspection apparatus which can test | inspect a cylindrical body with a few cameras without leaking in the circumferential direction.

  The cylindrical body appearance inspection method according to the embodiment is characterized in that the cylindrical body is photographed by a camera that rotates around the cylindrical body, and the appearance is determined based on the photographed image. In addition, the cylindrical appearance inspection apparatus according to the embodiment includes a camera that photographs the cylindrical body while rotating around the cylindrical body.

  According to the appearance inspection method and the appearance inspection apparatus of the embodiment, the surface of the cylindrical body can be inspected without omission in the circumferential direction with a small number of cameras.

The front view of the external appearance inspection apparatus A. FIG. Sectional drawing in the center of the left-right direction of the external appearance inspection apparatus A. The right view of the appearance inspection apparatus A (the lifting device 2, the camera 10, and the lights 11a and 11b are omitted). Sectional drawing in aa in FIG. FIG. 3 is a development view of a cylindrical body C showing a shooting range by the camera 10.

  In the following description, front and rear refers to front and rear in the traveling direction of the cylindrical body C. The left and right are expressions when the upstream side is viewed from the downstream side in the traveling direction of the cylindrical body C.

(Structure of appearance inspection device A)
The external appearance inspection apparatus A of the cylindrical body C of embodiment is shown in FIGS. The appearance inspection apparatus A is provided at a location in the traveling direction of the cylindrical body C molded by the continuous molding apparatus. The continuous molding apparatus is an apparatus for continuously molding a rubber or resin cylindrical body C such as a rubber hose or a resin hose.

  As shown in FIGS. 1 and 4, in the appearance inspection apparatus A, a camera 10 that captures the surface of the cylindrical body C and illuminations 11 a and 11 b that illuminate the surface of the cylindrical body C are used as a lifting device 2 that lifts and lowers them. It is attached. The lifting device 2 is fixed to the frame 3. The inside of the frame 3 is a passage place for the cylindrical body C. Further, as shown in FIG. 3, a rotating device 4 for rotating the frame 3 is provided. When the rotating device 4 operates and the frame 3 rotates, the camera 10 and the lights 11a and 11b rotate around the cylindrical body C passing through the inside of the frame 3. These members are housed inside the rack 5 in which bars are assembled. Details of this structure will be described below.

  The frame 3 is assembled so that the rods form a rectangular parallelepiped. The frame 3 is attached to the rack 5 in a rotatable state. The following is a detailed description based on FIG. 1 and FIG. Pipes 31 a and 31 b protruding outward are fixed on the front and rear of the frame 3. On the other hand, the rack 5 is provided with housings 32a and 32b protruding inward. The outer rings of the bearings 30a and 30b are fitted into the housings 32a and 32b on the rack 5 side, and the inner rings of the bearings 30a and 30b are fitted to the outer diameter sides of the pipes 31a and 31b on the frame 3 side. As a result, the frame 3 can rotate with respect to the rack 5.

  The rotation device 4 includes a rotation motor 40, a driving pulley 43, a driven pulley 41, and a belt 42. This will be described in detail with reference to FIG. 2 and FIG. A driven pulley 41 is fixed to the pipe 31a in front of the frame 3, so that the frame 3 and the driven pulley 41 can rotate simultaneously. On the other hand, a rotation motor 40 is fixed to the rack 5. A driving pulley 43 is fixed to the rotating shaft of the rotating motor 40, and a belt 42 is hung on the driving pulley 43 and the driven pulley 41. Due to this configuration, when the rotation motor 40 is operated, the driving pulley 43 and the driven pulley 41 rotate, and the frame 3 rotates.

  Note that the inner diameters of the pipes 31 a and 31 b fixed before and after the frame 3 are larger than the diameter of the cylindrical body C. A hole 44 having a diameter larger than that of the cylindrical body C is formed in the vicinity of the center in the radial direction of the driven pulley 41 fixed to the pipe 31a. Therefore, the cylindrical body C can advance from the rear side to the front side of the appearance inspection apparatus A through the inner diameter side of the pipes 31 a and 31 b and the hole 44 of the driven pulley 41.

  Here, the rotation axes of the frame 3, the pipes 31a and 31b, and the driven pulley 41 coincide. Further, these rotational axes coincide with the central axis of the cylindrical body C passing through the inside of the frame 3.

  As shown in FIGS. 1 and 3, the bearing 30a, the pipe 31a and the driven pulley 41 are, for example, an octagonal cover 33a when viewed from the front, and the bearing 30b and the pipe 31b are, for example, an octagonal cover 33b when viewed from the front. It may be covered.

  The lifting device 2 fixed to the frame 3 includes a ball screw 21 and a lifting motor 20 that rotates a screw shaft of the ball screw 21. A column 29 is provided near the center in the front-rear direction of the frame 3, and the bracket 22 is fixed to the column 29. The bracket 22 protrudes from the frame 3 to one of the left and right. A lifting motor 20 is fixed to the bracket 22. The ball screw 21 extends upward from the lifting motor 20 when the appearance inspection apparatus A is stopped.

  A camera 10 and illuminations 11 a and 11 b are attached to the ball screw 21 of the lifting device 2. The details will be described with reference to FIGS. 1 and 4. A first holder 24 that is kept horizontal and extends rearward is fixed to the nut 23 of the ball screw 21. The first holding tool 24 holds the second holding tool 25 extending vertically in the vicinity of the rear end. A camera holder 26 is fixed to the upper part of the second holder 25 and is held horizontally and extended to the center in the left-right direction of the frame 3. This camera holder 26 holds the camera 10 above the center of the frame 3 in the left-right direction. The camera 10 is held downward. With the above structure, the camera 10 is held behind the lifting device 2 in a state facing the cylindrical body C from above the cylindrical body C passing through the inside of the frame 3.

  Further, a left side illumination holder 27 a is provided below the second holder 25. A third holder 28 extending in the left-right direction is held near the center of the first holder 24 extending in the front-rear direction. On the right side of the third holder 28, a right illumination holder 27b is provided. The illumination holders 27a and 27b hold the illuminations 11a and 11b, respectively. The two lights 11a and 11b are obliquely below the camera 10 and are arranged symmetrically with respect to the cylindrical body C passing through the inside of the frame 3 when viewed from above. The illuminations 11a and 11b are fixed at a predetermined angle with respect to the horizontal plane. This predetermined angle is an angle that appropriately illuminates the surface of the cylindrical body C when the surface of the cylindrical body C reaches the focal point of the camera 10, and is, for example, 15 to 25 degrees. Here, appropriately illuminating is to illuminate the camera 10 so that an image that can determine the appearance of the cylindrical body C can be taken. The illuminations 11a and 11b can appropriately illuminate the entire photographing range of the camera 10.

  In the above structure, since the camera 10 and the lights 11a and 11b are attached to the same nut 23 of the ball screw 21, the positional relationship between the camera 10 and the lights 11a and 11b is fixed. And if the raising / lowering apparatus 2 act | operates, the camera 10 and illumination 11a, 11b will raise / lower with the positional relationship fixed.

  Due to the above structure, when the rotating device 4 operates, the frame 3 rotates, and the camera 10 and the lights 11a and 11b rotate around the rotation axis of the frame 3 while maintaining the positional relationship. Accordingly, when the rotating device 4 is operated while the cylindrical body C is passing through the inside of the frame 3, the camera 10 and the illuminations 11a and 11b rotate around the cylindrical body C. In addition, when the lifting device 2 is operated and the camera 10 and the lights 11a and 11b are moved up and down, the rotation radii of the camera 10 and the lights 11a and 11b change. Therefore, the lifting device 2 functions as a turning radius changing device for the camera 10 and the lights 11a and 11b.

  Furthermore, the appearance inspection apparatus A includes a determination unit 60 that determines the appearance of the cylindrical body C based on an image captured by the camera 10. The determination part 60 should just be determined based on the image image | photographed with the camera 10, and the specific structure and determination method are not limited.

  Furthermore, the appearance inspection apparatus A includes an operation unit 61 that performs an operation for inspection. The operation unit 61 includes an input unit for inputting the outer diameter of the cylindrical body C to be inspected. When the outer diameter of the cylindrical body C is input at this input unit, the lifting device 2 is activated, and the camera 10 and the illuminations 11a and 11b are moved to an optimum height for photographing the cylindrical body C having the outer diameter. Yes.

(Inspection method by appearance inspection device A)
When the appearance inspection apparatus A is stopped, the camera 10 is directly above the place through which the cylindrical body C passes. In this state, first, the outer diameter of the cylindrical body C to be inspected is input in the operation unit 61. Then, the lifting / lowering device 2 operates, and the height of the camera 10 and the illuminations 11a and 11b, that is, the rotation radius of the camera 10 and the illuminations 11a and 11b during the operation of the rotation device 4 is changed. As a result, the focus of the camera 10 is aligned with the apex of the cylindrical body C passing through the inside of the frame 3. Further, the lights 11a and 11b come to positions where the top of the cylindrical body C is appropriately illuminated.

  When the continuous molding apparatus starts operating in this state, the cylindrical body C is molded and proceeds to the appearance inspection apparatus A.

  When the distal end of the cylindrical body C reaches the photographing position by the camera 10, the rotating device 4 operates, the frame 3 starts rotating, and the camera 10 starts to turn around the cylindrical body C. The camera 10 first rotates in one of the left and right directions, for example, the clockwise direction. And if it goes around the cylindrical body C once, the rotating device 4 stops and the movement of the camera 10 also stops. Here, it is desirable that the last shooting range when the camera 10 goes around the cylindrical body C and the shooting range when shooting starts overlap. While the movement of the camera 10 is stopped, the rotation device 4 switches the rotation direction. Thereafter, the rotating device 4 is activated again. Then, the camera 10 rotates in the opposite direction to the front, for example, in the counterclockwise direction. And if it makes one round counterclockwise, the rotation apparatus 4 will stop and the movement of the camera 10 will also stop. In this way, the operation and stop of the rotating device 4 are repeated, and the rotation direction is switched each time the stop is performed. Therefore, every time the camera 10 makes a round around the cylindrical body C, the camera 10 stops at that position, and then rotates in the direction opposite to that before the stop. Such movement of the camera 10 is repeated until the cylindrical body C has passed the visual inspection apparatus A. The camera 10 takes a picture of the surface of the cylindrical body C while rotating around the cylindrical body C. However, when the camera 10 does not move in the circumferential direction of the cylindrical body C, no image is taken. The speed at which the camera 10 turns around the cylindrical body C is set to a speed higher than a certain level at which no omission of photographing occurs on the surface of the cylindrical body C moving forward. That is, the speed is such that all surfaces of the cylindrical body C can be photographed at least once.

  As an example, the forward travel speed of the cylindrical body C is 7.5 mm / second, the one-time shooting range of the camera 10 is 100 mm in the front-rear direction, for example, 15 mm in the circumferential direction, and the camera 10 for reversing the turning direction. FIG. 5 is a development view of the cylindrical body C. The photographing range when the time for stopping is 1 second and the speed at which the camera 10 rotates around the cylindrical body C is 15 rpm (4 seconds / rotation). In FIG. 5, the right side is the front of the cylinder C in the traveling direction. 5A to 5D show the same place of the cylindrical body C. FIG. Although shooting with the camera 10 is performed intermittently, the shooting time interval is 0.1 seconds, for example, which is very short relative to the speed of the cylinder C and the speed of rotation of the camera 10. Therefore, when the shooting range during one round of the camera 10 is shown on the development view, it becomes a substantially parallelogram.

  When the camera 10 makes one round around the cylindrical body C, the shooting range during that time is the range shown in FIG. The symbol L in the figure is the distance that the cylindrical body C travels forward during one round of the camera 10 and is 7.5 mm / second × 4 seconds / rotation × 1 rotation = 30 mm. Next, the moving direction of the camera 10 is reversed. Reference numeral 1 in the figure denotes a distance that the cylindrical body C travels forward while the camera 10 is stopped due to the reversal of the moving direction, and is 7.5 mm / second × 1 second = 7.5 mm. When the camera 10 makes one round in the direction after reverse rotation, the shooting range during that time becomes the range shown in FIG. During this time, the cylinder C advances 30 mm forward. Thereafter, the moving direction of the camera 10 is further reversed (while the cylinder C travels 7.5 mm), the camera 10 makes one turn in that direction, and the range shown in FIG. The cylinder C travels 30 mm). When the imaging ranges of the first and third rounds (FIGS. 5A and 5C) are overlapped, the range shown in FIG. 5D is obtained. Here, “a” in the figure indicates the shooting range of the first round, and “c” indicates the shooting range of the third round. As shown in FIG. 5D, there is a portion that overlaps the shooting range of the first round and the shooting range of the third round. The length in the front-rear direction of this overlapping portion is (length in the front-rear direction of one shooting range of the camera 10) − (distance that the cylinder C has traveled before the start of shooting in the range of FIG. 5C) = 100 mm− (30 mm + 7.5 mm + 30 mm + 7.5 mm) = 25 mm.

  In this example, as is apparent from FIG. 5D, no photographing omission occurs on the surface of the cylindrical body C. In addition, the entire surface of the cylindrical body C is photographed without omission only by photographing on the odd number of turns. Therefore, including the imaging of the even number of turns, the entire surface of the cylindrical body C is imaged at least twice.

  The determination by the determination unit 60 is performed based on the image data thus captured. Although the determination method by the determination part 60 is not limited, For example, it performs as follows. First, image data captured by the camera 10 is taken into the determination unit 60. The determination unit 60 stores non-defective image data. Therefore, the determination unit 60 compares the captured data with the non-defective product data. The comparison is performed for each photographed image. As a result, if there is no difference between the two, it is determined that there is no abnormality in the shooting location in the cylindrical body C. On the other hand, if there is a difference between the two, it is determined that there is an abnormality in the shooting location. When a certain number of abnormal images continue, it is determined that there is a scratch or the like on the surface of the cylindrical body C, and the cylindrical body C is determined to be a defective product.

  When the diameter of the continuously formed cylindrical body C changes, the outer diameter of the cylindrical body C is input in the operation unit 61. Then, the lifting / lowering device 2 operates, and the heights of the camera 10 and the illuminations 11a and 11b, that is, the rotation radii of the camera 10 and the illuminations 11a and 11b are changed. At the time of this change, the positional relationship between the camera 10 and the illuminations 11a and 11b remains fixed.

(effect)
In the above-described appearance inspection method and appearance inspection apparatus A, the camera 10 is photographed while moving in the circumferential direction around the cylindrical body C moving forward. Inspection can be performed without leakage in the circumferential direction. Therefore, equipment introduction costs can be reduced.

  Further, since the illuminations 11a and 11b also rotate around the cylindrical body C together with the camera 10, it is possible to always illuminate the shooting location without arranging a large number of illuminations around the cylindrical body C. Therefore, the number of illuminations can be reduced, and the equipment introduction cost can be suppressed.

  In the case of the above embodiment, the cylindrical body C to be inspected is continuously molded, and is continuously molded during the inspection. Therefore, it is difficult to rotate the cylindrical body C. However, if the camera 10 is moved in the circumferential direction of the cylindrical body C without rotating the cylindrical body C, the cylindrical body C can be inspected without omission in the circumferential direction.

  As another method for inspecting the cylindrical body C in the circumferential direction without omission, there is a method in which the camera is fixed, the molded cylindrical body C is cut, and the cut cylindrical body C is rotated near the camera. is there. However, in order to do so, a rotating device for the cylindrical body C is required. As a result, the appearance inspection apparatus becomes large, and the equipment introduction cost increases. However, if the camera 10 is moved in the circumferential direction of the cylindrical body C without rotating the cylindrical body C as in the above embodiment, a rotating device for the cylindrical body C is not necessary, and the equipment can be made compact. Equipment installation costs can be reduced.

  Here, wiring is attached to the camera 10 and the illuminations 11a and 11b. Therefore, if the camera 10 and the illuminations 11a and 11b are rotated around the cylindrical body C many times, the wiring may be wound around the cylindrical body C or a part of the appearance inspection apparatus A. However, if the direction of rotation is reversed each time the camera 10 goes around the cylindrical body C as in the above embodiment, the wiring can be prevented from being wound around the cylindrical body C or the like. .

  Further, by setting the speed of the camera 10 around the cylindrical body C to be a certain speed or more, the surface of the cylindrical body C traveling forward is photographed not only in the circumferential direction but also in its traveling direction. The entire surface of the cylindrical body C can be inspected. If the speed of turning around the cylindrical body C of the camera 10 is increased and the entire surface of the cylindrical body C is photographed twice or more by the camera 10, it is possible to prevent missing defects.

  Since the appearance inspection apparatus A includes the lifting device 2 as a rotation radius changing device, the rotation radius of the camera 10 is changed when the outer diameter of the cylinder C changes, and the focus of the camera 10 is set on the surface of the cylinder C. Can be matched. Therefore, it is possible to inspect cylindrical bodies having various diameters.

  Moreover, according to said external appearance inspection apparatus A, the positional relationship of the camera 10 and illumination 11a, 11b does not change, when a rotation radius changes. Therefore, the distance between the camera 10 and the lights 11a and 11b and the angle between the direction of the camera 10 and the direction of the lights 11a and 11b are maintained. For this reason, when the turning radius of the camera 10 is changed, it is not necessary to take time and effort to adjust the positions and angles of the illuminations 11a and 11b. Further, in the above-described appearance inspection apparatus A, the camera 10 and the illuminations 11a and 11b are provided on the same ball screw 21 and are moved up and down by one lifting motor 20, so that it is not necessary to prepare a plurality of lifting motors.

  Further, the appearance inspection apparatus A includes the operation unit 61, and the rotation radius of the camera 10 can be changed by setting in the operation unit 61. Therefore, it is necessary for an operator to take time and effort to change the rotation radius. No.

  In addition, when the presence or absence of abnormality is determined by comparing the image data photographed by the camera 10 with the non-defective image data as described above, a defect having no irregularities, for example, a small scratch or discoloration is recognized as an abnormality. It is possible to sort defective products reliably.

(Example of change)
In the case of the above embodiment, the direction in which the camera 10 rotates is switched every time the camera 10 makes one round around the cylindrical body C. However, the switching of the moving direction may be performed every time the camera 10 makes a plurality of rounds of two or more rounds. Further, the camera 10 may move only in one direction during the inspection.

  In the above embodiment, the turning radius changing device is the lifting device 2 including the ball screw 21 and the lifting motor 20, but the structure of the turning radius changing device is not limited to this. For example, instead of the lifting device 2, a device including a hydraulic cylinder and a piston may be used. In that case, the camera 10 and the lights 11a and 11b are fixed to the piston, and these are moved up and down by hydraulic control.

  The structure for rotating the camera 10 and the illuminations 11a and 11b around the cylindrical body C is not limited to that of the above embodiment. For example, a circular orbit having a diameter larger than that of the cylindrical body C is provided so as to surround the cylindrical body C from the outer diameter side, and the camera 10 and the illuminations 11a and 11b move on the circular orbit to move around the cylindrical body C. A rotating structure may be used.

  The inspection may not be performed while the cylindrical body is continuously formed. For example, the inspection may be performed on the cylindrical body after the molding is finished and cut into a predetermined length.

A: Appearance inspection device, C: Cylindrical body, 2 ... Lifting device, 3 ... Frame, 4 ... Rotating device, 5 ... Rack, 10 ... Camera, 11a ... Lighting, 11b ... Lighting, 20 ... Lifting motor, 21 ... Ball Screws, 22 ... brackets, 23 ... nuts, 24 ... first holder, 25 ... second holder, 26 ... camera holder, 27a ... illumination holder, 27b ... illumination holder, 28 ... third holder, 29 ... pillar, 30a ... bearing, 30b ... bearing, 31a ... pipe, 31b ... pipe, 32a ... housing, 32b ... housing, 33a ... cover, 33b ... cover, 40 ... motor for rotation, 41 ... driven pulley, 42 ... belt , 43 ... Drive side pulley, 44 ... Hole, 60 ... Determination part, 61 ... Operation part

Claims (3)

  An appearance inspection method for a cylindrical body, in which a cylindrical body is photographed with a camera that moves around the cylindrical body, and an appearance is determined based on the photographed image.   An external appearance inspection apparatus for a cylindrical body, comprising a camera that photographs the cylindrical body while rotating around the cylindrical body.   An illumination that illuminates the cylindrical body while rotating around the cylindrical body together with the camera, and a rotation radius changing device that changes the rotation radius of the camera and the illumination while fixing the positional relationship between the camera and the illumination. An appearance inspection apparatus for a cylindrical body according to 1.

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