JP6491000B2 - Screw inspection device - Google Patents

Description

  The present invention relates to a screw inspection apparatus for inspecting the appearance of a screw.

  2. Description of the Related Art Conventionally, there is known an inspection apparatus that inspects a screw by conveying the screw by a conveyor, photographing the fed screw with a video camera from the side, and processing the image information by an image processing unit ( For example, see Patent Document 1.)

JP 7-83853 A

  However, in the above-described technique, since the screw can be imaged only from one direction, a region that becomes a blind spot of the video camera, such as the back side of the screw, is large. If there is a defective portion in such a blind area of the video camera, it is impossible to detect a screw defect, and there is a disadvantage that the inspection accuracy is lowered. Although it is conceivable to pick up images of screws from a plurality of directions using a plurality of cameras, in this case, a plurality of cameras are required, and there is a disadvantage that the cost of the inspection apparatus increases. It is conceivable to rotate the screw and shoot multiple times with one camera, but in this case, there is a disadvantage that the inspection time increases.

  An object of the present invention is to provide a screw inspection apparatus capable of improving the inspection accuracy of a screw while reducing the possibility of increasing the inspection time and the cost of the inspection apparatus.

  A screw inspection apparatus according to the present invention includes: a conveyance unit that conveys a screw along a conveyance path that passes through a preset inspection position; an imaging unit that captures an imaging range including the inspection position; It has a reflecting surface that is distributed to both sides across the conveyance path and is disposed so as to surround the inspection position, and each reflects an image of a side surface of the screw that is positioned at the inspection position so that it can be imaged by the imaging unit. A plurality of reflecting members and an inspection unit that determines the quality of the screw based on an image captured by the imaging unit.

  According to this configuration, the image of the side surface of the screw located at the inspection position is reflected by the imaging unit so as to be imaged by the plurality of reflecting members having reflection surfaces arranged so as to surround the inspection position. An image obtained by viewing the side surface from a plurality of directions is captured as a single image. Since the inspection unit determines the quality of the screw based on this image, as a result of reducing the area where the imaging blind spot is smaller than when imaging the screw from one direction as in the background art, the screw inspection accuracy is improved. Can do. In addition, the image obtained by viewing the screw side surface from a plurality of directions can be captured as a single image by a single imaging unit, so there is no need to use a plurality of imaging units, thereby reducing the possibility of increasing the cost of the inspection apparatus. can do. In addition, an image obtained by viewing the screw side surface from a plurality of directions can be captured as a single image by a single imaging operation, and therefore it is not necessary to rotate the screw and perform imaging multiple times, resulting in an increase in inspection time. Can be reduced.

  Further, the imaging unit performs the imaging from an extension line of a screw axis located at the inspection position, and each of the reflecting members reflects an optical path length that is reflected from the screw by the reflection surface and reaches the imaging unit. The angle of inclination of the reflecting surface with respect to the axis so that the difference in the reflected light path length generated according to the position of the image reflected by each reflecting surface is equal to or less than the depth of field of the imaging unit. Is preferably set.

  According to this configuration, since the imaging unit is focused on the entire image reflected on each reflecting member, the imaging unit can clearly capture the entire image of the screw side viewed from a plurality of directions into a single image. It becomes.

  In addition, the optical path length from the tip of the screw to the imaging unit without passing through the reflection surface is a direct optical path length, and the imaging unit is greater than the difference between the plurality of reflected optical path lengths and the direct optical path length. It is preferable to have a depth of field.

  According to this configuration, the imaging unit can clearly capture the entire image including the tip portion of the screw in one image in addition to the image reflected on each reflecting member.

  The transport unit includes a transport member having a flat upper surface, and the head of the screw is placed on the upper surface and the shaft of the screw is upright along the transport path. It is preferable that the screw is conveyed by being moved, and the plurality of reflecting members reflect an image of a side surface of the screw head portion and the shaft portion to the imaging unit.

  According to this configuration, since the head portion of the screw is placed on the upper surface of the conveying member and conveyed in an upright posture, the images reflected on the plurality of reflecting members include the side surfaces of the head portion. Therefore, the imaging unit can capture an image obtained by viewing both side surfaces of the screw shaft and the head from a plurality of directions in one image. Thereby, the inspection unit can inspect the shaft portion and the head portion of the screw from one image imaged by the imaging unit.

  Moreover, it is preferable that the said conveyance part contains the upright maintenance means for maintaining the said screw mounted in the upper surface of the said conveyance member in an upright state.

  According to this configuration, it is easy to increase the screw conveyance speed.

  Moreover, it is preferable that the said upright maintenance means performs the damping control which controls the movement of the said conveyance member so that the shaking of the said screw mounted in the upper surface of the said conveyance member may be reduced.

  According to this configuration, the screws placed on the upper surface of the conveying member by the control method can be easily maintained in the upright state without using a member such as an adhesive or a magnet as the upright maintaining means.

  In addition, the transport section has a pair of transport guide sections that are narrower than the diameter of the head of the screw and wider than the outer diameter of the screw, and extend parallel to each other along the transport path, The screw is transported in a state where the seating surface of the head is supported by the pair of transport guide portions and the shaft portion is suspended from the interval, and the plurality of reflecting members are arranged on the side surface of the shaft portion of the screw. It is preferable to reflect an image to the imaging unit.

  According to this configuration, since the shaft portion of the screw extends in the direction of the imaging unit due to the action of gravity, it is easy to make the screw have a posture in which the image of the side surface is reflected on the plurality of reflecting members.

  The screw inspection device having such a configuration can improve the inspection accuracy of the screw while reducing the possibility that the inspection time increases and the cost of the inspection device increases.

It is a front view showing an example of composition of a screw inspection device concerning a 1st embodiment of the present invention. It is the perspective view which looked at the test | inspection block and screw classification box shown in FIG. 1 from diagonally upward. It is the perspective view which looked at the conveyance guide part and mirror unit shown in FIG. 2 from diagonally downward. It is the bottom view which looked at the conveyance guide part and mirror unit shown in FIG. 2 from the downward direction. It is sectional drawing which shows the VV cross section of FIG. It is a front view which shows an example of a structure of the screw inspection apparatus which concerns on 2nd Embodiment of this invention. It is the perspective view which looked at the test | inspection block shown in FIG. 6 from diagonally upward. FIG. 8 is a top view of the conveyor belt and the mirror unit shown in FIGS. 6 and 7 as viewed from above.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.

  (First embodiment)

  FIG. 1 is a front view showing an example of the configuration of the screw inspection apparatus 1 according to the first embodiment of the present invention. A screw inspection apparatus 1 shown in FIG. 1 generally includes an inspection block 2, a screw supply block 3, and a screw sorting box 4. The screw supply block 3 supplies the inspection target screw to the inspection block 2. The inspection block 2 inspects the screws supplied from the screw supply block 3, classifies them into good products and defective products, and discharges them to the screw sorting box 4.

  The screw sorting box 4 is a container for receiving and receiving the screw inspected by the inspection block 2 from the inspection block 2. As shown in FIG. 2, the screw sorting box 4 includes a non-defective product container 41 that houses a non-defective product and a defective product container 42 that houses a defective product.

  FIG. 2 is a perspective view of the inspection block 2 and the screw sorting box 4 shown in FIG. 1 as viewed obliquely from above. The inspection block 2 shown in FIG. 2 includes a conveyance mechanism 5 (conveyance unit), a camera 6, a mirror unit 7, an illumination unit 8, and an air gun 9.

  The transport mechanism 5 transports the screw B supplied from the screw supply block 3 along the transport path 53 passing through the inspection position P. The transport mechanism 5 has a pair of transport guide portions 51 and 52 that are narrower than the diameter of the head Bh of the screw B and wider than the outer diameter of the screw B, and extend parallel to each other along the transport path 53. doing. A pair of conveyance guide parts 51 and 52 are installed so that it may extend substantially horizontally linearly.

  The conveyance guide parts 51 and 52 are plate-shaped members, such as stainless steel, for example. Endless belts 511 and 521 are attached along the opposite sides of the conveyance guide portions 51 and 52. The endless belt 511 is wound around pulleys 512, 513, 514, 515, and 516 so that a part of the endless belt 511 extends along the side of the transport guide portion 51 that faces the transport guide portion 52. The endless belt 521 is wound around pulleys 522, 523, 524, 525, and 526 so that a part of the endless belt 521 extends along the side of the transport guide portion 52 that faces the transport guide portion 51.

  The pulleys 514 and 524 are rotationally driven by a conveyance motor (not shown) so that the endless belts 511 and 521 travel in the conveyance direction A within the interval between the conveyance guide portions 51 and 52. . Air guns 9 for blowing air obliquely forward in the transport direction are disposed on both sides near the end portions of the transport guide portions 51 and 52 of the air gun 9, respectively.

  In the screw B, the seat surface of the head Bh is supported by the upper surfaces of the conveyance guide portions 51 and 52, and the shaft portion Ba of the screw B is suspended from the gap between the conveyance guide portions 51 and 52. In this state, the endless belts 511 and 521 travel in the transport direction A, whereby the screws B supported by the transport guide portions 51 and 52 are transported in the transport direction A.

  FIG. 3 is a perspective view of the conveyance guide portions 51 and 52 and the mirror unit 7 shown in FIG. 2 as viewed obliquely from below. 4 is a bottom view of the conveyance guide portions 51 and 52 and the mirror unit 7 shown in FIG. 2 as viewed from below. The mirror unit 7 shown in FIG. 3 and FIG. 4 is extended by inclining at a predetermined inclination angle from the four corners of the frame 75 to a central direction of the frame 75 with a substantially square frame 75. And reflecting portions 71, 72, 73, 74. The inspection position P is arranged in a region surrounded by the tip portions of the reflecting portions 71, 72, 73, 74.

  Mirrors M1, M2, M3, and M4 (reflecting members) are attached to the reflecting portions 71, 72, 73, and 74 on the surface facing the inspection position P, respectively. The mirrors M1, M2, M3, and M4 are arranged so that most of the mirrors M1, M2, M3, and M4 fall within the imaging range 61 of the camera 6. FIG. 4 shows a state in which the screw B is located at the inspection position P. On the mirrors M1, M2, M3, and M4, images B1, B2, B3, and B4 of the side surface of the screw B located at the inspection position P are shown. Hereinafter, the mirrors M1, M2, M3, and M4 are collectively referred to as a mirror M.

  FIG. 5 is a cross-sectional view showing a VV cross section of FIG. 4. In FIG. 5, the description of the reflecting portion 72 is omitted. As shown in FIG. 5, the mirrors M1 and M4 are configured by forming silver plating layers M12 and M42 on the back surfaces of glass plates M11 and M41. Similarly to the mirrors M1 and M4, the mirrors M2 and M3 are configured by forming silver plating layers M22 and M32 on the back surfaces of the glass plates M21 and M31. In this case, the surfaces of the silver plating layers M12, M22, M32, and M42 correspond to an example of a reflecting surface.

  Note that the reflection member may be any member that specularly reflects light. For example, a prism may be used as the reflection member. When a prism is used as a reflecting member, the surface (interface) of the prism that reflects light is the reflecting surface.

  The lighting unit 8 is attached to the lower side of the frame body 75. The illumination unit 8 includes a reflecting member 81, an annular portion 82, and a plurality of light emitting diodes 83. The reflection member 81 has a substantially semicircular hemispherical shell shape in a side sectional view, and is attached so as to cover the frame body 75. The inner surface of the reflecting member 81 is, for example, a white rough surface, and diffusely reflects light (diffuse reflection). In the vicinity of the top of the reflecting member 81, an opening 84 for imaging the imaging range 61 with the camera 6 is formed.

  The annular portion 82 is an annular plate member. The annular portion 82 is attached so as to protrude inward from the opening end of the reflecting member 81. A plurality of light emitting diodes 83 are attached to the lower surface of the annular portion 82 so as to be distributed over the entire lower surface.

  Light output from the plurality of light emitting diodes 83 is emitted to the inner surface of the reflecting member 81, is diffusely reflected by the inner surface of the reflecting member 81, and the screw B is illuminated. Thereby, since the screw B is illuminated by the diffused light, the illumination light hitting the screw B includes light hitting the screw B at various angles. As a result, the image of the screw B illuminated with such illumination light is reflected by the mirror unit 7 to the camera 6 and is imaged by the camera 6, so that defects such as scratches generated on the screw B from the captured image. Can be easily detected.

  The camera 6 is configured using an imaging lens 62 and, for example, a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor) image sensor, or the like. The imaging lens 62 is provided on an extension line of the axis of the screw B, that is, is arranged so that the tip of the screw B is positioned on the optical axis of the imaging lens 62. As a result, the camera 6 images the imaging range 61 centered on the screw B through the opening 84.

  The optical path that reaches the imaging lens 62 from the lower part of the screw B via the mirror M is the imaging optical path K1, and the optical path that reaches the imaging lens 62 via the mirror M from the screw body of the screw B is the imaging optical path K2. An optical path that reaches the imaging lens 62 via the mirror M from the side surface of the tip of the imaging lens is an imaging optical path K3. Reflected optical path lengths K1L, K2L, and K3L that are optical path lengths of the imaging optical paths K1, K2, and K3 are relative to the optical axis of the imaging lens 62 of the reflecting surfaces R1, R2, R3, and R4 of the mirror M (with respect to the axis of the screw B). ) Varies depending on the tilt angle.

  Therefore, the inclination angles of the reflecting surfaces R1, R2, R3, and R4 are set so that the differences among the reflected light path lengths K1L, K2L, and K3L are less than the depth of field of the camera 6. As a result, since the camera 6 is focused on the entire images B1, B2, B3, and B4 reflected on the mirrors M1, M2, M3, and M4, the camera 6 displays a single image obtained by viewing the side surface of the screw B from four directions. A clear image can be captured.

  When the optical path length of the imaging optical path K4 that reaches the imaging lens 62 directly from the end surface of the screw B without passing through the mirror M is the direct optical path length K4L, the reflected optical path lengths K1L, K2L, K3L and the direct optical path length K4L are mutually. The depth of field of the camera 6 and the inclination angles of the reflecting surfaces R1, R2, R3, and R4 may be set so that the difference between them is equal to or less than the depth of field of the camera 6. In this case, the camera 6 can clearly capture the image of the tip of the screw B as a single image in addition to the image obtained by viewing the side surface of the screw B from four directions.

  The screw inspection apparatus 1 includes an unillustrated inspection unit that determines the quality of the screw B based on an image captured by the camera 6. The inspection unit is configured using, for example, a microcomputer, and determines whether the screw B is good or bad by comparing an image captured by the camera 6 with a good product image, for example. The inspection unit conveys and discharges the screw B determined to be a non-defective product by the conveyance mechanism 5 and releases the compressed air from the air gun 9 on the conveyance guide unit 52 side to thereby remove the screw B discharged from the conveyance mechanism 5. It is stored in the container 41. On the other hand, the screw B determined to be defective is transported and discharged by the transport mechanism 5, and the compressed air is discharged from the air gun 9 on the transport guide portion 51 side, whereby the screw B discharged from the transport mechanism 5 is defective. The container 42 is stored.

  As described above, according to the screw inspection apparatus 1, an image obtained by viewing the side surface of the screw B from four directions can be picked up as a single image. As a result of the decrease, the inspection accuracy of the screw B can be improved. In addition, since one camera 6 can capture the image of the side surface of the screw B viewed from four directions as a single image, there is no need to use a plurality of cameras, which may increase the cost of the inspection apparatus. Can be reduced. Further, since the image obtained by viewing the side surface of the screw B from four directions can be picked up as a single image by a single image pickup operation, there is no need to rotate the screw and pick up multiple times, resulting in an increase in inspection time. The fear can be reduced.

  In addition, although the example which arrange | positions two mirrors M1 and M2 on one side and has arrange | positioned two mirrors M3 and M4 on the other side on both sides of the conveyance path 53 was shown, the number of mirrors of the conveyance path 53 is shown. There may be one on each side, or three or more on each side. As the number of mirrors is increased, it is possible to capture an image with less distortion on the side surface of the screw B and a blind spot, and thus the inspection accuracy is improved. On the other hand, if the number of mirrors is increased, the cost increases. Therefore, the number of mirrors may be determined as appropriate according to the balance between required inspection accuracy and cost.

Moreover, although the mirror unit 7, the illumination unit 8, and the camera 6 were provided under the conveyance guide parts 51 and 52 and the example which test | inspects the axial part Ba of the screw B was shown, the mirror unit 7, the illumination unit 8, and It is good also as a structure which equips the upper side of the conveyance guide parts 51 and 52 with the camera 6 arranged upside down, and test | inspects the head Bh of the screw B. FIG. Moreover, it is good also as a structure which equips the upper and lower sides of the conveyance guide parts 51 and 52 with the mirror unit 7, the illumination unit 8, and the camera 6, and test | inspects the axial part Ba of the screw B, and the head Bh.
(Second Embodiment)

  Next, a screw inspection apparatus 1a according to a second embodiment of the present invention will be described. FIG. 6 is a front view showing an example of the configuration of the screw inspection apparatus 1a according to the second embodiment of the present invention. The screw inspection apparatus 1a shown in FIG. 6 differs from the screw inspection apparatus 1 shown in FIG. 1 in the following points.

  That is, the screw inspection apparatus 1 a shown in FIG. 6 includes an inspection block 2 a and a screw supply block 3 a instead of the inspection block 2 and the screw supply block 3. Further, a good product discharge port 43 and a defective product discharge port 44 are provided instead of the good product container 41 and the defective product container 42. The inspection block 2a includes a transport mechanism 5a, a camera 6, a mirror unit 7, an illumination unit 8, and a defective product discharge air gun (not shown).

  The inspection unit conveys and discharges the screw B determined to be non-defective to the non-defective discharge port 43 by the transfer mechanism 5a. On the other hand, the screw B determined to be defective is discharged to the defective product discharge port 44 by discharging compressed air from the defective product discharge air gun while being transferred by the transfer mechanism 5a.

  FIG. 7 is a perspective view of the inspection block 2a shown in FIG. 6 as viewed obliquely from above. 6 and 7, in inspection block 2a, transport mechanism 5a is configured by a belt conveyor. The transport mechanism 5 a is configured such that a transport belt 54 (transport member) is looped between a drive pulley 55 and a tail pulley 56. The upper surface of the conveyor belt 54 is flat. A substantially central portion in the belt width direction on the upper surface of the conveyance belt 54 has a width slightly larger than the head Bh of the screw B, and is a conveyance path 53 that extends through the inspection position P along the conveyance direction.

  The screw supply block 3 a places the screw B on the upper surface of the conveying belt 54 at the upstream end of the conveying path 53 with the head Bh of the screw B facing down. The transport mechanism 5a transports the screw B in the transport direction with the inverted posture with the head Bh down.

  The inspection block 2a maintains the screw B in an upright state by performing vibration control to control the movement of the conveyor belt 54 so as to reduce the vibration of the screw B placed on the upper surface of the conveyor belt 54. Transport control unit (upright maintaining means). The transport mechanism 5a and the transport control unit correspond to an example of a transport unit.

  The conveyance control unit is configured using, for example, a microcomputer. As a method of controlling vibration control, for example, the technology described in “Case of Time Reduction Effect” (Catalog No. SBCZ-037A) published by OMRON Corporation, the publication of a paper in the Department of Mechanical Engineering, Department of Mechanical Engineering, Faculty of Engineering, Yamanashi University, etc. Known control techniques can be used.

  Note that the upright maintaining means is not necessarily limited to the transport control unit. For example, an adsorbing unit that adsorbs the head Bh of the screw B on the upper surface of the conveying belt 54 may be provided as an upright maintaining unit. As the adsorbing means, for example, an adhesive layer obtained by applying an adhesive to the upper surface of the conveyance belt 54, a magnet that adsorbs the head Bh of the screw B to the upper surface of the conveyance belt 54 by magnetism, or the like can be used. .

  Further, it may be possible to transport the belt with the shaft of the screw B upright by reducing the traveling speed of the transport belt 54 without providing an upright maintaining means. However, it is more preferable to provide the upright maintaining means in that it is possible to increase the conveying speed of the screw B by including the upright maintaining means.

  In addition, by providing the conveyance control unit, the screw B is maintained in an upright state without causing adhesive to adhere to the head Bh of the screw B or magnetizing the screw B, and the conveyance speed of the screw B can be increased. It is more preferable to provide a conveyance control unit as an upright maintaining means in that it can be increased.

  About the other structure, since the screw inspection apparatus 1a is comprised similarly to the screw inspection apparatus 1 shown in FIG. 1, the description is abbreviate | omitted.

  FIG. 8 is a top view of the transport belt 54 and the mirror unit 7 shown in FIGS. 6 and 7 as viewed from above. According to the screw inspection apparatus 1a, the head Bh of the screw B is placed on the upper surface of the transport belt 54 and transported in an upright posture, so that it is reflected on the mirrors M1, M2, M3, and M4 as shown in FIG. Images B1, B2, B3, and B4 include the side surface of head Bh. Therefore, the camera 6 can capture an image obtained by viewing the side surfaces of both the shaft portion Ba and the head Bh of the screw B from four directions in one image. As a result, the above-described inspection unit can inspect the shaft portion Ba and the head Bh of the screw B from one image captured by the camera 6.

1, 1a Inspection device 2, 2a Inspection block 3, 3a Supply block 4 Sorting box 5, 5a Conveying mechanism (conveying unit)
6 Camera (imaging part)
7 Mirror unit 8 Illumination unit 9 Air gun 41 Non-defective container 42 Defective container 43 Non-defective product discharge port 44 Defective product discharge port 51, 52 Conveyance guide portion 53 Conveyance path 54 Conveyance belt 55 Drive pulley 56 Tail pulley 61 Imaging range 62 Imaging lens 71, 72 , 73, 74 Reflecting portion 75 Frame 81 Reflecting member 82 Ring portion 83 Light emitting diode 84 Opening portion 511, 521 Endless belt A Conveying direction B Screw B1, B2, B3, B4 Image Ba Shaft portion Bh Head portion K1, K2, K3, K4 Imaging optical path K1L, K2L, K3L Reflected optical path length K4L Direct optical path length M1, M2, M3, M4 Mirror M11, M21, M31, M41 Glass plate M12, M22, M32, M42 Silver plating layer P Inspection position R1, R2 , R3, R4 reflective surface

Claims (3)

A transport unit that transports a screw along a transport path that passes through a preset inspection position;
An imaging unit for imaging an imaging range including the inspection position;
Within the imaging range, the image is distributed to both sides across the conveyance path and is arranged so as to surround the inspection position, and each reflects an image of the side surface of the screw positioned at the inspection position so that it can be captured by the imaging unit. A plurality of reflecting members each having a reflecting surface;
An inspection unit that determines the quality of the screw based on the image captured by the imaging unit ;
The conveyance unit includes a conveyance member having a flat upper surface, and moves the conveyance member along the conveyance path in a state where the screw head is placed on the upper surface and the shaft of the screw is upright. To transport the screws,
The plurality of reflecting members are screw inspection devices that reflect images of side surfaces of the screw head and the shaft portion to the imaging unit . The transport unit, the screw placed on the upper surface of the conveying member, the screw inspection apparatus of claim 1 including upstanding maintaining means for maintaining the upright. The screw inspection apparatus according to claim 2 , wherein the upright maintaining unit performs vibration control to control movement of the conveying member so as to reduce shaking of the screw placed on the upper surface of the conveying member.

Images