Abstract:
Provided is a filler connection part inspection method by which the connection state of both end surfaces of a belt-shaped filler that has been affixed annularly along the outer periphery of a bead core is inspected. The filler connection part inspection method includes a step of obtaining data of the distance between optical sensors and side surfaces of the filler by scanning, at the side surfaces of the filler, sections of the vicinity of the both end surfaces along the tangential direction of the filler over a predetermined scanning range with the optical sensors, a step of repeating the data obtaining step while the positions of the optical sensors are changed along the radial direction of the filler, and a step of comparing the obtained data with reference data that is set in advance.

Description:
RELATED APPLICATIONS 
     The present invention is a U.S. National Stage under 35 USC 371 patent application, claiming priority to Serial No. PCT/JP2013/080036, filed on 6 Nov. 2013; the entirety of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a method for inspecting a connected portion of a filler in which a strip of a filler is adhered to the outer circumference of a bead core for a vehicle tire, the two end surfaces of the filler are adhered and connected to each other, and then the state of the connected portion is inspected. 
     As shown in  FIG. 11 , in a typical vehicle tire, an annular bead core  52  and an annular filler  53  are embedded in the inner rim of each of the two sidewalls of a tire rubber  51 . A strip of the filler  53  is adhered to the outer circumference of the bead core  52  in advance as shown in  FIG. 12A . Then, the two end surfaces  531  and  532  are adhered and connected to each other as shown in  FIGS. 12B and 13  so that the filler  53  attached to the bead core  52  becomes annular. Patent document 1 discloses a structure in which a filler is adhered to the outer circumference of a bead core, and the two end surfaces of the filler are connected to each other. 
     When the filler  53  is attached to the bead core  52  in this manner, a connection defect may occur at the portion where the two end surfaces  531  and  532  of the filler  53  are connected as shown in  FIGS. 14A to 14D . More specifically,  FIG. 14A  shows a situation in which a gap is formed in the outer circumferential end of the connected portion.  FIG. 14B  shows a situation in which a step is formed in the outer circumferential end of the connected portion.  FIG. 14C  shows a situation in which a gap is formed in the middle of the connected portion.  FIG. 14D  shows a situation in which the end surfaces of the connected portion are displaced in the thickness-wise direction. 
     PRIOR ART DOCUMENT 
     Patent Document 
     Patent Document 1: Japanese Laid-Open Patent Publication No. 2003-127249 
     SUMMARY OF THE INVENTION 
     In the prior art, when attaching the filler  53  to the bead core  52 , after adhering and connecting the two end surfaces  531  and  532  of the filler  53  to each other, the connected portion is visually checked and inspected by an inspector to find products that have a defective connection as described above. 
     Patent document 1 discloses a structure for connecting the two end surfaces of a filler but does not disclose how to inspect for defective connections. 
     In the conventional method for inspecting the connected portion of the filler, an inspector visually inspects the connected portion of the filler  53 . Thus, the inspection is difficult. In particular, the filler  53 , which has a black color, is difficult to check visually and requires inspection skills. Thus, inspection results cannot be obtained with high accuracy. 
     Accordingly, it is an object of the present invention to provide a filler connected portion inspection method that allows the state of the connected portion of two end surfaces of a filler to be easily and accurately inspected without requiring skill. 
     To achieve the above object, one aspect of the present invention provides a filler connected portion inspection method for inspecting a connection state of two end surfaces of a strip of a filler adhered along an outer circumference of a bead core into an annular form. The filler connected portion inspection method includes the steps of obtaining data of a distance from an optical sensor to a side surface of the filler by scanning a portion proximate to the two end surfaces at the side surface of the filler in a tangential direction of the filler over a predetermined scanning range with the optical sensor, repeating the step of obtaining data while changing a position of the optical sensor in a radial direction of the filler, and comparing the obtained data with reference data that is set in advance. 
     The filler connected portion inspection method allows the connected portion to be easily and accurately inspected through optical scanning without the need for an inspector to visually check the state of the connected portion. Further, the comparison of the data that is obtained through optical scanning with the reference data that is set in advance allows the determination of whether or not the connection is defective to be performed with high accuracy. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view showing a first embodiment of a filler connected portion inspection device. 
         FIG. 2  is an enlarged plan view of the inspection device shown in  FIG. 1 . 
         FIG. 3  is a cross-sectional view taken along line  3 - 3  in  FIG. 2 . 
         FIG. 4  is a partial front view showing optical scanning performed on a connected portion of a filler by an optical sensor. 
         FIG. 5A  is an enlarged cross-sectional view taken along line  5 - 5  in  FIG. 4 , and  FIG. 5B  is an enlarged cross-sectional view of a filler in a further example. 
         FIG. 6  is a diagram showing data for the vicinity of the connected portion in the filler obtained through optical scanning. 
         FIG. 7  is a diagram showing the cross-sectional shape of the filler derived from the data obtained in the vicinity of each connected portion at the two side surfaces of the filler. 
         FIG. 8  is a block diagram showing the configuration for controlling the filler connected portion inspection device. 
         FIG. 9  is a partial side view showing a second embodiment of a filler connected portion inspection device. 
         FIG. 10  is a partial front view showing optical scanning conducted on a connected portion of a filler by an optical sensor of the connected portion inspection device shown in  FIG. 9 . 
         FIG. 11  is a partial cross-sectional view showing a vehicle tire. 
         FIGS. 12A and 12B  are partial front views showing a method for attaching a filler to a bead core. 
         FIG. 13  is a partial enlarged cross-sectional view taken along line  13 - 13  in  FIG. 12 . 
         FIGS. 14A to 14C  are partial front views showing different connection defects in the two end surfaces of a filler, and  FIG. 14D  is a partial cross-sectional view showing a further connection defect. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     A filler connected portion inspection device according to a first embodiment of the present invention will now be described with reference to  FIGS. 1 to 8 . 
     As shown in  FIG. 1 , a filler connected portion inspection device includes a base  21 . A support ring  22  having the shape of a truncated cone is coupled by a bracket  23  to the base  21 . The support ring  22  is held so that its center axis extends horizontally. The upper portion of the support ring  22  includes an opening  221  forming by cutting out part of the support ring  22  in the circumferential direction. An annular assembled unit of a bead core  52  and a filler  53  is attached to the outer circumference of the support ring  22 . The strip of the filler  53  is adhered to the outer circumference of the bead core  52  in a state inclined relative to the radial direction of the bead core  52 . As shown by the double-dashed line in  FIG. 1 , the filler  53  may be adhered to extend in the radial direction from the bead core  52  instead of being inclined relative to the radial direction. In this state, the two end surfaces  531  and  532  of the filler  53  are adhered and connected to each other. The portion of the filler  53  where the two end surfaces  531  and  532  are connected to each other is arranged in correspondence with where the opening  221  of the support ring  22  is located. Further, as shown in  FIGS. 2 and 5A , the end surfaces  531  and  532  of the filler  53  are each defined by an inclined surface  533 , which is inclined relative to the thickness-wise direction of the filler  53 . In detail, the end surfaces  531  and  532  of the filler  53  are each formed by the inclined surface  533  that is inclined so that the thickness of the filler  53  gradually decreases toward the distal end. The inclined surfaces  533  of the end surfaces  531  and  532  of the filler  53  are opposed to each other and connected. As shown in  FIG. 5A , the inclined surfaces  533  are adhered to each other. As shown in  FIG. 5B , instead of being inclined, the two end surfaces  531  and  532  of the filler  53  may extend parallel to the thickness-wise direction of the filler  53 . 
     As shown in  FIGS. 1 and 2 , a support  24  is fixed to the base  21  by a bracket  25 . Two first guide rails  27  are fixed to a front surface (right surface as viewed in  FIGS. 1 and 2 ) of the support  24 . The first guide rails  27  extend substantially parallel to the direction the filler  53  is inclined in the opening  221  of the support ring  22 . A first movable base  26  is supported by the two first guide rails  27  on the support  24  to be movable along the first guide rails. Two second guide rails  29  extending parallel to the first guide rails  27  are fixed to the front surface of the first movable base  26 . A second movable base  28  is supported by the second guide rails  29  on the first movable base  26  to be movable along the second guide rails  29 . Thus, the second movable base  28  is movable in the same direction as the first movable base  26 . 
     Two third guide rails  31 , which extend perpendicular to the direction the first rails guides  27  extend, are fixed to the front surface of the second movable base  28 . A third movable base  30  is supported by the third guide rails  31  on the second movable base  28  to be movable along the third guide rails  31 . The third movable base  30  is movable in a direction perpendicular to the movement direction of the first movable base  26  and the second movable base  28 . More specifically, the third movable base  30  is movable in the tangential direction of the filler  53  in the opening  221  of the support ring  22 . A scanning member  32  is fixed to the front surface of the third movable base  30 . The scanning member  32  has a substantially C-shaped form in a side view and includes two arms  321 , one at the front and one at the rear. The arms  321  of the scanning member  32  respectively support optical sensors  33 A and  33 B, which are of a laser light type. The optical sensors  33 A and  33 B respectively oppose the two side surfaces of the connected portion of the filler  53  through the opening  221  of the support ring  22 . The scanning member  32  is inclined in correspondence with the filler  53  that is inclined. The scanning member  32  is not inclined when the filler  53  is not inclined as shown by the double-dashed line in  FIG. 1 . 
     As shown in  FIGS. 1 and 2 , a movement cylinder  35 , which is located on the first movable base  26 , includes a piston rod coupled to the second movable base  28 . The movement cylinder  35  is actuated to move the second movable base  28  along the second guide rails  29 . This moves the optical sensors  33 A and  33 B, which are supported by the scanning member  32 , between a separated position P 1 , which is where the optical sensors  33 A and  33 B are separated upward from the connected portion of the filler  53  as shown by the solid lines in  FIG. 1 , and an inspection initiation position P 2 , which is where the optical sensors  33 A and  33 B are located in correspondence with the outer circumference of the filler  53 . 
     As shown in  FIGS. 2 and 3 , a reciprocation motor  36  is arranged on the second movable base  28 . A rotary disk  37  is fixed to the motor shaft of the reciprocation motor  36 . The rotary disk  37  includes an eccentric crank pin  371 . The third movable base  30  includes a connection pin  301 . A crank rod  38  connects the crank pin  371  of the rotary disk  37  to the connection pin  301  of the third movable base  30 . The reciprocation motor  36  rotates the rotary disk  37 . The crank rod  38  converts rotation of the rotary disk  37  to reciprocation of the third movable base  30  along the third guide rails  31 . This reciprocates the optical sensors  33 A and  33 B, which are supported by the scanning member  32 , within a predetermined width in the tangential direction of the filler  53  at opposite sides of the filler  53 . Referring to  FIG. 4 , the optical sensors  33 A and  33 B perform linear optical scanning on the portion of the filler  53  proximate to the connected portion from opposite sides of the filler  53  over a predetermined scanning range L 1  in the tangential direction of the filler  53 . The optical sensors  33 A and  33 B each detect the distance to the corresponding side surface of the filler  53  to obtain data of the distance. 
     As shown in  FIGS. 1 and 2 , a pitch-feed motor  39  and a ball screw  43 , which extends parallel to the first guide rails  27 , are arranged on the support  24 . A drive pulley  40  is fixed to the motor shaft of the pitch-feed motor  39 . A driven pulley  42  is fixed to the ball screw  43 . A timing belt  41  runs around the drive pulley  40  and the driven pulley  42 . The first movable base  26  is formed to be engaged with the ball screw  43 . The pitch-feed motor  39  generates rotation that rotates the ball screw  43  through the drive pulley  40 , the timing belt  41 , and the driven pulley  42 . The rotation of the ball screw  43  moves the first movable base  26  along the first guide rails  27 . The movement of the first movable base  26  changes the positions of the optical sensors  33 A and  33 B, which are supported by the scanning member  32 , in the radial direction of the filler  53 . When the optical sensors  33 A and  33 B reach each of the two ends of the scanning range L 1 , the first movable base  26  is moved to move the optical sensors  33 A and  33 B by a predetermined feed pitch L 2  in the radial direction of the filler  53 . Consequently, as shown in  FIG. 4 , the optical sensors  33 A and  33 B repetitively perform optical scanning while changing positions by moving over a predetermined feed pitch L 2  in the radial direction of the filler  53  from the inspection initiation position P 2  to an inspection completion position P 3 , which are shown by broken lines in  FIG. 1 . 
     The configuration for controlling the filler connected portion inspection device will now be described. 
     As shown in  FIG. 8 , the filler connected portion inspection device includes a controller  45  that controls the operation of the entire inspection device. Programs used to control the operation of the inspection device and data used to execute the programs are stored in a memory  46 . The controller  45  is connected to the optical sensors  33 A and  33 B, an operation unit  47 , and a display  48 . The controller  45  receives, from the optical sensors  33 A and  33 B, data of the distance from each of the optical sensors  33 A and  33 B to the corresponding side surface of the filler  53 . The controller  45  also receives operation command signals from the operation unit  47 . The controller  45  sends, to the display  48 , the data obtained by the optical sensors  33 A and  33 B and determination data of whether or not the connection is defective in the filler  53 . The data is shown on the display  48 . 
     When the controller  45  receives data of the vicinity of the connected portion of the filler  53  from the optical sensors  33 A and  33 B, the controller  45  shows an image of the data on the display  48 . Further, the controller  45  compares the data with reference data, which is stored in advance in the memory  46 , and determines whether or not the connection of the two end surfaces  531  and  532  of the filler  53  is defective. Referring to  FIG. 6 , in this case, it is preferred that the controller  45  exclude data D 2  obtained at the two ends of the scanning range L 1  and use only data D 1  obtained at the middle of the scanning range L 1 . 
     When the controller  45  receives an operation command signal from the operation unit  47  for checking the cross-section state of the filler  53 , the controller  45  obtains the cross-sectional shape of the connected portion from the data obtained by scanning the two side surfaces of the filler  53 . Then, the controller  45  shows an image of the cross-sectional shape  534  on the display  48 . Further, the controller  45  compares the obtained cross-sectional shape with a reference shape stored in advance in the memory  46  to check the cross-section and determine whether or not the connection is defective. 
     A method for inspecting the connection of the two end surfaces  531  and  532  of the filler  53  with the filler connected portion inspection device will now be described. 
     In the filler connected portion inspection device, prior to an inspection, the piston rod of the movement cylinder  35  is retracted and the second movable base  28  is moved toward the upper side as viewed in  FIG. 1 . Thus, the optical sensors  33 A and  33 B, which are supported by the scanning member  32 , are located at the upper separated position P 1  as shown by the solid lines in  FIG. 1 . Under this situation, a strip of the filler  53  is adhered to the outer circumference of the bead core  52 , which is supported by the outer circumference of the support ring  22 , into an annular form. Then, a device (not shown) presses the opposite sides of the filler  53  to adhere and connect the two end surfaces  531  and  532  of the filler  53  to each other. Here, the portion of the filler  53  where the two end surfaces  531  and  532  are connected is arranged in correspondence with the position of the opening  221  in the support ring  22 . 
     Then, the connection state of the filler  53  is inspected with the filler connected portion inspection device. 
     The piston rod of the movement cylinder  35  is projected to move the second movable base  28  to the lower side as viewed in  FIG. 1 . This moves the optical sensors  33 A and  33 B, which are supported by the scanning member  32 , from the separated position P 1 , which is shown by the solid lines in  FIG. 1 , to the inspection initiation position P 2 , which is shown by the broken lines. As a result, the two optical sensors  33 A and  33 B are respectively opposed to the two side surfaces of the outer circumferential end of the connected portion of the filler  53  through the opening  221  of the support ring  22 . 
     When the optical sensors  33 A and  33 B are located at the inspection initiation position P 2 , the reciprocation motor  36  generates rotation that rotates the rotary disk  37 . The crank rod  38  converts rotation of the rotary disk  37  to reciprocation of the third movable base  30  along the third guide rails. This reciprocates the optical sensors  33 A and  33 B, which are supported by the scanning member  32 , within a predetermined width in the tangential direction of the filler  53  at opposite sides of the filler  53 . Referring to  FIG. 4 , the optical sensors  33 A and  33 B perform linear optical scanning on the portion of the filler  53  proximate to the connected portion from opposite sides of the filler  53  over a predetermined scanning range L 1  in the tangential direction of the filler  53 . The optical sensors  33 A and  33 B each detect the distance to the corresponding side surface of the filler  53  and obtain data of the distance. 
     Whenever the optical sensors  33 A and  33 B, which are supported by the scanning member  32 , reach each of the two ends of the scanning range L 1 , the pitch-feed motor  39  generates rotation. The rotation of the pitch-feed motor  39  is transmitted by the drive pulley  40 , the timing belt  41 , and the driven pulley  42  to the ball screw  43 . This rotates the ball screw  43 . As the ball screw  43  rotates, the first movable base  26  is intermittently moved toward the lower side as viewed in  FIG. 1 . Consequently, as shown in  FIG. 4 , the optical sensors  33 A and  33 B repetitively perform optical scanning, while being moved by the predetermined feed pitch L 2  in the radial direction of the filler  53 , to change positions from the inspection initiation position P 2  to the inspection completion position P 3 , which are shown by broken lines in  FIG. 1 . 
     In this manner, the optical sensors  33 A and  33 B perform optical scanning on the connected portion of the filler  53  until reaching the inspection completion position P 3  and send the scan data of the vicinity of the connected portion to the controller  45 . When the controller  45  receives the data, the controller  45  shows an image of the data on the display  48  as shown in  FIG. 6 . Further, the controller  45  compares the data with the reference data stored in the memory  46  and determines whether or not the connection of the two end surfaces  531  and  532  of the filler  53  is defective. The determination result is shown on the display  48 . In this case, as shown in  FIG. 6 , the data D 2  obtained at the two ends of the scanning range L 1  is excluded, and only the data D 1  obtained at the middle of the scanning range L 1  is used for the comparison and determination. 
     Further, when the controller  45  receives an operation command signal from the operation unit  47  for checking the cross-section of the filler  53 , the controller  45  obtains the cross-sectional shape of the connected portion from the data obtained by scanning the two side surfaces of the filler  53 . Then, the controller  45  shows an image of the cross-sectional shape on the display  48 . Further, the controller  45  compares the obtained cross-sectional shape with the reference shape stored in the memory  46  to check the cross-section and determine whether or not the connection is defective. 
     When determined that the connected portion of the filler  53  includes a defective connection such as that shown in  FIGS. 14A to 14D  (non-connected part included or two end surfaces  531  and  532  displaced relative to each other in the radial direction or the circumferential direction), the determination is shown on the display  48  to notify the inspector. In this case, for example, a buzzer may be used to present the notification. 
     Accordingly, the first embodiment has the advantages described below. 
     (1) In the first embodiment, a strip of the filler  53  is adhered along the outer circumference of the bead core  52  into an annular form, and the two end surfaces  531  and  532  of the filler  53  are adhered to each other. Then, the state of the connected portion is inspected. In this case, the optical sensors  33 A and  33 B scan the vicinity of the portion where the two end surfaces  531  and  532  of the filler  53  are connected at the sides of the filler  53  over the predetermined scanning range in the tangential direction of the filler  53 . Here, a step of obtaining data of the distance from the optical sensors  33 A and  33 B to the corresponding side surfaces of the filler  53  is performed. As the positions of the optical sensors  33 A and  33 B change in the radial direction of the filler  53 , the step of obtaining data is repeated. Then, the obtained data is compared with the reference data, which is set in advance. 
     Thus, the filler connected portion inspection method allows the connected portion to be easily and accurately inspected through optical scanning without the need for an inspector to visually check the state of the connected portion. Further, the comparison of the data that is obtained through optical scanning with the reference data that is set in advance allows the determination of whether or not the connection is defective to be performed with high accuracy. 
     (2) In the first embodiment, the two end surfaces  531  and  532  of the filler  53  are inclined relative to the thickness-wise direction of the filler  53 . This ensures a large area of contact between the two end surfaces  531  and  532  of the filler  53  and reduces defective contact where the two end surfaces  531  and  532  contact each other. 
     (3) In the first embodiment, optical scanning is performed on the two side surfaces of the filler  53 . This allows the state of the two side surfaces at the connected portion of the filler  53  to be simultaneously inspected. 
     (4) In the first embodiment, the cross-sectional shape at the vicinity of the two end surfaces  531  and  532  of the filler  53  is derived from the data obtained from the two side surfaces of the filler  53 . Then, the derived cross-sectional shape is compared with the reference shape that is set in advance. Thus, the comparison of the cross-sectional shape, which is based on the data of the two side surfaces of the filler  53  obtained by the optical sensors  33 A and  33 B, with the reference shape, which is set in advance, allows the determination of whether or not the connection is defective to be performed with high accuracy. 
     (5) In the first embodiment, the data D 2  obtained at the two ends of the scanning range L 1  is excluded. Only the data D 1  obtained at the middle of the scanning range L 1  is used. This allows the determination of whether or not the connection is defective to be accurately performed. Accordingly, the data amount of the inspected subject can be reduced, and the speed for processing the inspection can be increased. 
     Second Embodiment 
     A second embodiment of a filler connected portion inspection method will now be described focusing on differences from the first embodiment. 
     In the second embodiment, as shown in  FIGS. 9 and 10 , among the two arms  321  of the scanning member  32 , the front arm  321  supports two optical sensors  33 A that are spaced apart in the vertical direction, and the rear arm  321  supports two optical sensors  33 B that are spaced apart in the vertical direction. The two pairs of the optical sensors  33 A and  33 B are configured so that they can be opposed to the vicinity of the two end surfaces  531  and  532  at opposite sides of the filler  53 . The optical scanning of the connected portion of the filler  53  by the optical sensors  33 A and  33 B is simultaneously performed on the region from the outer circumference to the middle of the filler  53  in the radial direction and the region from the middle to the inner circumference of the filler  53 . 
     In addition to the advantages of the first embodiment, the second embodiment has the advantages described below. 
     (6) In the second embodiment, the optical sensors  33 A and  33 B that are spaced apart in the radial direction of the filler  53  perform optical scanning of the connected portion of the filler  53  simultaneously in a plurality of different regions arranged in the radial direction of the filler  53 . This reduces the time used to inspect the state of the connected portion of the filler  53 . 
     Modified Example 
     The above embodiments may be modified as described below. 
     Three or more optical sensors  33 A and  33 B may be arranged on each arm  321 , and the optical scanning of the connected portion of the filler  53  may be simultaneously performed on three or more regions in the radial direction of the filler  53 . 
     In each of the above embodiments, laser light is used to perform inspections. Instead, inspections may be performed through image processing that uses visible light. 
     DESCRIPTION OF REFERENCE CHARACTERS 
       22 ) support ring,  24 ) support,  26 ) first movable base,  28 ) second movable base,  30 ) third movable base,  32 ) scanning member,  33 A and  33 B) optical sensors,  35 ) movement cylinder,  36 ) reciprocation cylinder,  37 ) rotary disk,  38 ) crank rod,  39 ) pitch-feed motor,  43 ) ball screw,  45 ) controller,  46 ) memory,  48 ) display, L 1 ) scanning range, L 2 ) feed pitch.