Patent Publication Number: US-2021178714-A1

Title: Forming device for green tire

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of Japanese Patent Application No.: 2019-225706 filed on Dec. 13, 2019, the content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Technical Field 
     The present invention relates to a forming device for a green tire. 
     Related Art 
     A pneumatic tire disclosed in JP 2017-109517 A discontinuous carcass ply positioned on the inner side in the tire radial direction of a tread portion. The carcass ply includes a pair of ply pieces extending from the tread portion to one of a pair of bead portions. In the center of the tread portion, a region where neither of the two ply pieces exists, that is, a hollow portion is provided. 
     SUMMARY 
     The pneumatic tire of JP 2017-109517 A is completed by vulcanizing a green tire formed by winding a plurality of tire components including a pair of ply pieces around a forming drum. A forming device for this green tire requires two servicers, each of which supplies a pair of ply pieces. However, JP 2017-109517 A does not consider at all the reduction of the installation space. 
     An object of the present invention is to reduce the installation space of the forming device for a green tire including a carcass ply having a hollow portion. 
     One aspect of the present invention provides a forming device for a green tire including a discontinuous carcass ply, the discontinuous carcass ply including a pair of ply pieces having an inner end portion positioned on an inner side in a tire radial direction of a tread portion and a side portion extending to an inner side in the tire radial direction from the inner end portion and positioned on an inner side in a tire width direction of a sidewall portion. The forming device includes a first servicer that sends out a strip-shaped first sheet for forming a plurality of the ply pieces, a drum around which the first sheet from the first servicer is wound, a first cutting portion that cuts the first sheet in order to separate one of the ply pieces, a moving mechanism for relatively moving the first servicer and the drum in an axial direction of the drum, and a control unit that controls the moving mechanism so that the first servicer and the drum are relatively moved to a first position for forming one of the pair of ply pieces and a second position for forming the other one of the pair of ply pieces in this order. 
     In the present aspect, a pair of ply pieces can be formed with a first servicer by relatively moving the first servicer and the drum in the axial direction of the drum by the moving mechanism. That is, in the forming device which normally requires two servicers, only one servicer needs to be installed. Therefore, as compared with the case where two servicers are disposed, the installation space of the forming device for the green tire including the carcass ply having a hollow portion can be reduced. 
     Each of a pair of the ply pieces is formed from a first sheet (cloth). Since there is substantially no width variation in a first sheet, the rubber volume on both sides in the tire width direction of the green tire can be made uniform. Further, since one and the other one of a pair of the ply pieces are wound separately, the rotation angle position of the start end to be wound around the drum can be easily adjusted. The start end and the termination of the ply piece are overlapping regions, and these regions can be disposed at different positions in the tire circumferential direction. Accordingly, the uniformity of the completed pneumatic tire can be improved. 
     The moving mechanism moves only the drum. 
     In the present aspect, the moving mechanism of the existing forming facility for forming a green tire by winding the tire components around the drum that has been moved sequentially can be used. Therefore, by modifying the existing forming facility, it is possible to easily realize the forming device that forms a pair of the ply pieces with one servicer. 
     The green tire includes a ply that extends to the inner end portion of each of the pair of ply pieces, and has a central portion positioned on an inner side in a tire radial direction of the inner end portion and a pair of side portions extending from both ends of the central portion to an inner side in the tire radial direction. The forming device includes a second servicer, which is disposed adjacent to the first servicer in an axial direction of the drum and sends out a strip-shaped second sheet for forming a plurality of the plies, and a second cutting portion that cuts the second sheet in order to separate one of the plies. The control unit controls the moving mechanism so that the first servicer, the second servicer, and the drum relatively move to the first position from a third position for forming the ply. 
     When viewed from an axial direction of the drum, the control unit makes a rotation angle position of a start end of the first sheet wound around the drum different between one and the other one of the pair of ply pieces. 
     In the present aspect, it is possible to prevent the overlap regions, in which the rubber volume is locally increased, from concentrating on a part in the circumferential direction, so that the uniformity of the completed pneumatic tire can be improved. 
     a third servicer, which is disposed adjacent to the first servicer in an axial direction of the drum and sends out a strip-shaped third sheet for forming a plurality of the ply pieces, and a third cutting portion that cuts the third sheet in order to separate one of the ply pieces are included. The first sheet and the third sheet differ in at least one of a width, a rubber material, and the number of cords. 
     In the present aspect, since the sheets of different types can be disposed in one forming device, the time required for switching a production line can be shortened when pneumatic tires with carcass plies of different types is manufactured. 
     In the present invention, the installation space of a forming device for a green tire including a carcass ply having a hollow portion can be reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and the other features of the present invention will become apparent from the following description and drawings of an illustrative embodiment of the invention in which: 
         FIG. 1  is a perspective view showing a forming device for a green tire according to a first embodiment of the present invention; 
         FIG. 2  is a side view of the forming device of  FIG. 1 ; 
         FIG. 3  is a plan view of a forming drum; 
         FIG. 4  is a block diagram of the forming device of  FIG. 1 ; 
         FIG. 5A  is a plan view showing a state in which a first ply is formed; 
         FIG. 5B  is a perspective view showing a state in which the first ply is formed; 
         FIG. 6A  is a plan view showing a state in which one of a pair of ply pieces is formed; 
         FIG. 6B  is a perspective view showing a state in which one of a pair of the ply pieces is formed; 
         FIG. 7A  is a plan view showing a state in which the other one of a pair of the ply pieces is formed; 
         FIG. 7B  is a perspective view showing a state in which the other one of a pair of the ply pieces is formed; 
         FIG. 8  is a cross-sectional view showing a state in which the first ply and a pair of the ply pieces are wound; 
         FIG. 9  is a flowchart showing control by a control device; 
         FIG. 10  is a plan view of a forming device for a green tire according to a second embodiment; 
         FIG. 11  is a meridian cross-sectional view of a green tire; and 
         FIG. 12  is a cross-sectional view of a tread portion of a green tire and its surroundings. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 
     (First Embodiment) 
       FIG. 1  shows a ply forming unit  31  in a forming device  30  of a green tire  1  according to a first embodiment of the present invention. A forming facility including the forming device  30  assembles a plurality of tire components in a cylindrical shape to form the cylindrical green tire  1  shown in  FIG. 11 . By vulcanizing the green tire  1  with a vulcanization device (not shown), a pneumatic tire made from rubber is completed. 
     First, a configuration of the green tire  1  will be specifically described. 
     As shown in  FIG. 11 , the green tire  1  includes a tread portion  2 , a pair of sidewall portions  3 , and a pair of ring-shaped bead portions  4 . 
     The tread portion  2  includes tread rubber  5  extending in the tire width direction (indicated by the reference numeral TW in  FIG. 11 ). The pneumatic tire completed by vulcanization is provided with a groove on the surface of the tread portion  2 , that is, the tread surface. 
     Each of a pair of the sidewall portions  3  includes side rubber  6  extending from both ends of the tread portion  2  to the inner side in the tire radial direction (reference numeral TR in  FIG. 11 ). 
     A pair of the bead portions  4  are disposed in end portions on the inner side in the tire radial direction of a pair of the sidewall portions  3 . Each of the bead portions  4  includes a bead core  7  and a bead filler  8 . The bead core  7  includes a large number of steel wires bundled in a ring shape. The bead filler  8  has a ring shape and is made from rubber that is harder than rubber that constitutes the tread portion  2  and the sidewall portion  3 . The bead filler  8  includes a base end  8   a  disposed adjacent to the outer side in the tire radial direction of the bead core  7  and a tip end  8   b  on the side opposite to the base end  8   a,  and extends in a tapered shape from the base end  8   a  to the outer side in the tire radial direction toward the tip end  8   b.  Each of the bead portions  4  includes strip rubber  9  provided to wrap the bead core  7  and the bead filler  8 . 
     The green tire  1  includes a carcass  12  hung in a toroidal shape between the bead portions  4 . In the present embodiment, the carcass  12  includes a first carcass ply (hereinafter, referred to as “first ply”)  11  and a second carcass ply (hereinafter, referred to as “second ply”)  12 . The second ply  14  is a ply having a hollow portion  14   a,  while the first ply  13  is a normal ply having no hollow portion. The first ply  11  and the second ply  12  will be described in detail later. An inner liner  10  is provided on the inner side of the carcass  12 , that is, on the innermost peripheral surface of the green tire  1 . 
     Referring to  FIG. 12 , an endless belt layer  18  is provided between the tread rubber  5  and the carcass  12 . In the present embodiment, the belt layer  18  includes two belts  19  and  20 . The belt  19  is disposed adjacent to the outer side in the tire radial direction of the carcass  12 , and the belt  20  is disposed adjacent to the outer side in the tire radial direction of the belt  19 . Further, in the present embodiment, the dimension in the tire width direction of the belt  19  in the lower layer is larger than the dimension in the tire width direction of the belt  20  in the upper layer, and an end portion  19   a  of the belt  19  is positioned closer to the outer side in the tire width direction than an end portion  20   a  of the belt  20 . The belt layer  18  may be composed of one belt, or may include three or more belts. 
     An endless cap layer  22  is provided adjacent to the outer side in the tire radial direction of the belt layer  18 . The cap layer  22  of the present embodiment includes a pair of narrow edge plies  23  that directly cover either of the end portions  19   a  and  20   a  of the belts  19  and  20 . Further, the cap layer  22  of the present embodiment is disposed adjacent to the outer side in the tire radial direction of the edge ply  23 , and includes a wide cap ply  24  as a single sheet that covers the entire belts  19  and  20  including the end portions  19   a  and  20   a.  The cap layer  22  may include one or three or more plies. Further, the cap layer  22  may be eliminated. 
     A pair of endless pads  26  made from rubber are disposed between both ends on the outer side in the tire width direction of the belt layer  18  and the carcass  12 . The cross-sectional shape of the pad  26  is a flat triangular shape. The positions in the tire width direction of the end portions  19   a  and  20   a  of the belts  19  and  20 , the end portion  23   a  on the outer side in the tire width direction of the edge ply  23 , and an end portion  24   a  of the cap ply  24  are set in a region between an end portion  26   a  on the outer side in the tire width direction of the pad  26  and an end portion  26   b  on the inner side, that is, a region where the pad  26  exists. The pad  26  may be eliminated. 
     Hereinafter, the first ply  13  and the second ply  14  constituting the carcass  12  will be described. 
     Referring to  FIGS. 11 and 12 , the first ply  13  is a single ply, while the second ply  14  is a discontinuous ply having the hollow portion  14   a  as described above. The second ply  14  is composed of a pair of ply pieces  15 . 
     The first ply  13  includes a central portion  13   a  positioned on the inner side in the tire radial direction of the tread portion  2 , and a pair of side portions  13   b  extending from both ends in the tire width direction of the central portion  13   a  to the inner side in the tire radial direction. Further, the first ply  13  is provided continuously with the side portion  13   b,  and includes a wind-up portion  13   c  wound up from the inner side to the outer side in the tire width direction with respect to the bead core  7 . 
     The central portion  13   a  extends from one to the other of inner end portions  15   a  of each of a pair of the ply pieces  15 . More specifically, the range between the centers in the tire width direction of a pair of the pads  26  is the central portion  13   a.    
     The side portion  13   b  is disposed adjacent to the outer side in the tire width direction of the inner liner  10 . 
     The wind-up portion  13   c  is terminated in the sidewall portion  3 . More specifically, the wind-up portion  13   c  includes an inner portion  13   d , a winding portion  13   e,  and an outer portion  13   f.    
     The inner portion  13   d  is disposed closer to the inner side in the tire radial direction than the bead portion  4 , that is, the bead core  7  and the bead filler  8 , with the ply piece  15  interposed between them. 
     The winding portion  13   e  is provided continuously with the inner portion  13   d,  and is wound around the bead core  7  with the ply piece  15  interposed between them. 
     The outer portion  13   f  is provided continuously with the winding portion  13   e,  and is disposed closer to the outer side in the tire radial direction than the bead portion  4  with the ply piece  15  interposed between them. An end portion of the outer portion  13   f  constitutes an end portion  13   g  of the first ply  13 . The end portion  13   g  is positioned closer to the outer side in the tire radial direction than the tip end  8   b  of the bead filler  8  and is positioned closer to the inner side in the tire radial direction than the tread portion  2 . 
     The second ply  14  is disposed adjacent to the outer side in the tire radial direction of the first ply  13 , and is a discontinuous ply composed of a pair of the ply pieces  15 . The ply piece  15  has the inner end portion  15   a  disposed between the belt layer  18  and the central portion  13   a  of the first ply  13 . The pad  26  is interposed between the inner end portion  15   a  and the belt layer  18 . The position in the tire width direction of the inner end portion  15   a  of the ply piece  15  is set in the region on the outer side in the tire width direction of the tread portion  2 , more specifically, in the region closer to the inner side in the tire width direction to both the end portions  19   a  and  20   a  of the belts  19  and  20  constituting the belt layer  18 . The hollow portion  14   a  is provided in the region at the center in the tire width direction of the tread portion  2 , more specifically, in the region between the inner end portions  15   a  of a pair of the ply pieces  15 . In the hollow portion  14   a,  the second ply  14  does not exist, and only the central portion  13   a  of the first ply  13  exists. 
     The ply piece  15  includes a side portion  15   b  extending to the inner side in the tire radial direction from the inner end portion  15   a,  and a wind-up portion  15   c  wound up from the inner side to the outer side in the tire width direction with respect to the bead core  7 . 
     The side portion  15   b  is disposed adjacent to the outer side in the tire width direction of the side portion  13   b  of the first ply  13 . 
     The wind-up portion  15   c  is provided continuously with the side portion  15   b  and is terminated in the sidewall portion  3 . The wind-up portion  15   c  includes an inner portion  15   d,  a winding portion  15   e,  and an outer portion  15   f.    
     The inner portion  15   d  is disposed on the inner side in the tire radial direction of the bead portion  4 , more specifically, between the bead portion  4  and the inner portion  13   d  of the first ply  13 . 
     The winding portion  15   e  is provided continuously with the inner portion  15   d  and is wound around the bead core  7 . More specifically, the winding portion  15   e  is disposed between the bead core  7  and the winding portion  13   e  of the first ply  13 . 
     The outer portion  15   f  is provided continuously with the winding portion  15   e,  and is disposed closer to the outer side in the tire radial direction than the bead portion  4 . Of the outer portion  15   f,  a part positioned on the inner side in the tire radial direction is disposed so as to overlap the outer side in the tire radial direction of the bead portion  4 , and the rest is disposed so as to overlap the outer side in the tire radial direction of the side portion  15   b.  An end portion of the outer portion  15   f  constitutes an outer end portion  15   g  of the ply piece  15 . The outer end portion  15   g  is positioned closer to the outer side in the tire radial direction than the tip end  8   b  of the bead filler  8  and is positioned closer to the inner side in the tire radial direction than the tread portion  2 , more specifically, the end portion  13   g  of the first ply  13 . 
     The first ply  13 , the ply piece  15  of the second ply  14 , the belts  19  and  20 , and the plies  23  are  24  are all composed of a strip-shaped sheet in which a plurality of cords arranged side by side at intervals are covered with rubber. Other components than these and the bead core  7 , that is, the tread rubber  5 , the side rubber  6 , the bead filler  8 , the strip rubber  9 , the inner liner  10 , and the pad  26  are made from a rubber member. 
     The green tire  1  configured as described above is formed as described below. 
     First, the inner liner  10 , the strip rubber  9 , the first ply  13 , and a pair of the ply pieces  15  are laminated in this order to form a cylindrical carcass band. Subsequently, the carcass band is subjected to a step including bead setting and turn-up to form a cylindrical green case. Separately from the carcass band, the pad  26 , the belts  19  and  20 , the plies  23  and  24 , and the tread rubber  5  are laminated in this order to form a cylindrical tread band. After that, the green case disposed in the tread band is bulged to the outer side in the radial direction, and the carcass band is assembled with an inner peripheral portion of the tread band. 
     That is, forming of the green tire  1  includes a first forming step for forming the carcass band, a second forming step for forming the green case, a third forming step for forming the tread band, and a fourth forming step for assembling the green case and the tread band. A forming facility for the green tire  1  includes forming devices corresponding to the first forming step to the fourth forming step. 
       FIGS. 1 and 2  show the ply forming unit  31  of the first forming device  30  that performs the first forming step. The other configurations of the first forming device  30 , that is, the configuration of the forming unit for forming the inner liner  10  and the strip rubber  9  is similar to the conventional one. Further, the configurations of components other than the first forming device  30  are also similar to those in the conventional ones. 
     As shown in  FIGS. 1 and 2 , the ply forming unit  31  of the forming device  30  includes a first forming unit  40  for forming the first ply  13  and a second forming unit  50  for forming a pair of the ply pieces  15 . Further, the forming device  30  includes one forming drum  60  and a moving mechanism  70  for moving the forming drum  60 . The forming drum  60  wound with the inner liner  10  and the strip rubber  9  is moved to the first forming unit  40  and the second forming unit  50  in this order, and the first ply  13  and the second ply  14  are sequentially formed on the outer circumference of the forming drum  60 . 
     The first forming unit  40  and the second forming unit  50  have similar configurations, and are disposed adjacent to each other in the Y direction (axial direction) in which an axis A of the forming drum  60  extends. Specifically, the first forming unit  40  includes one servicer (second servicer)  41  for sending out a strip-shaped first ply sheet (second sheet)  13 ′ for forming a plurality of the first plies  13 . The second forming unit  50  includes one servicer (first servicer)  51  for sending out a strip-shaped ply piece sheet (first sheet)  15 ′ for forming a plurality of the ply pieces  15 . 
     That is, there is only one servicer  51  that forms a pair of the ply pieces  15 , and the servicer  51  forms one and the other one of a pair of the ply pieces  15  in order. In the description below, of a pair of the ply pieces  15 , the one positioned on the right side in  FIG. 12  may be referred to as a first ply piece  15 , and the one positioned on the left side in  FIG. 12  may be referred to as a second ply piece  15 . 
     As most clearly shown in  FIG. 2 , the first ply sheet  13 ′ and the ply piece sheet  15 ′ are wound around the same type of carriages  35  and set on the servicers  41  and  51 , respectively. The width of the first ply sheet  13 ′ in the Y direction corresponds to the width of the first ply  13  from one of a pair of the end portions  13   g  to the other. The width of the ply piece sheet  15 ′ in the Y direction corresponds to the width of the ply piece  15  from the inner end portion  15   a  to the outer end portion  15   g . The width of the ply piece sheet  15 ′ is smaller than the width of the first ply sheet  13 ′. By winding the ply piece sheet  15 ′ on the carriage  35  having a size capable of winding the first ply sheet  13 ′, the number of parts required for the forming facility is reduced. 
     The carriage  35  includes a winding shaft  36  having a total length capable of winding the first ply sheet  13 ′, a frame body  36  having a size surrounding the wound first ply sheet  13 ′, and a moving roller  38  attached to a lower part of the frame body  36 . The winding shaft  36  is rotatable with respect to the frame body  36 . 
     The servicer  41  of the first ply sheet  13 ′ and the servicer  51  of the ply piece sheet  15 ′ have substantially the same configurations and are disposed adjacent to each other in the Y direction. The servicer  41  of the first ply sheet  13 ′ includes a pair of unwinding rollers  42 , a conveyor  43 , a guide  44 , a cutting device (second cutting portion)  45 , and a holding roller  46 . The servicer  51  of the ply piece sheet  15 ′ includes a pair of unwinding rollers  52 , a conveyor  53 , a guide  54 , a cutting device (first cutting portion)  55 , and a holding roller  56 . All of these are disposed above the top of the forming drum  60 , and supply the first ply sheet  13 ′ and the ply piece sheet  15 ′ to the forming drum  60  from above. 
     The servicers  41  and  51  differ in that the widths in the Y direction along the axis A of the forming drum  60  are different. Specifically, the width of the servicer  51  of the first ply sheet  13 ′ is smaller than the width of the servicer  41  of the ply piece sheet  15 ′. The width of the servicer  41  corresponds to the width of the first ply sheet  13 ′, and the width of the servicer  51  corresponds to the width of the ply piece sheet  15 ′. 
     Each of the unwinding rollers  42  and  52  are rotated by an electric motor (not shown). Of a pair of the unwinding rollers  42  and a pair of the unwinding rollers  52 , the one positioned on the upper side rotates clockwise in  FIG. 2 , and the one positioned on the lower side rotates counterclockwise in  FIG. 2 . The first ply sheet  13 ′ wound around the carriage  35  is unwound by the drive of the unwinding roller  42  of the first forming unit  40 . The ply piece sheet  15 ′ wound around the carriage  35  is unwound by the drive of the unwinding roller  52  of the second forming unit  50 . 
     The conveyors  43  and  53  are disposed between the unwinding rollers  42  and  52  and the forming drum  60 . Each of the conveyors  43  and  53  is composed of a roller conveyor including a plurality of rollers disposed at intervals in the unwinding direction (X direction) of the sheets  13 ′ and  15 ′. The individual rollers extend in the width direction (Y direction) of the sheets  13 ′ and  15 ′. 
     The guides  44  and  54  are disposed between the conveyor  43  and the forming drum  60 . As most clearly shown in  FIG. 1 , the guide  44  of the first forming unit  40  is a square tubular frame body that determines the position where the first ply sheet  13 ′ is sent out, and includes an unwinding port  44   a  having a size through which the first ply sheet  13 ′ can be unwound. The guide  54  of the second forming unit  50  is a square tubular frame body that determines the position where the ply piece sheet  15 ′ is sent out, and includes an unwinding port  54   a  having a size through which the ply piece sheet  15 ′ can be unwound. 
     The cutting devices  45  and  55  are disposed between the guides  44  and  54  and the forming drum  60 . Referring to  FIG. 1 , the cutting device (second cutting portion)  45  of the first forming unit  40  includes a cutter  45   a  capable of advancing and retreating in the width direction (Y direction) of the first ply sheet  13 ′, and separates a first ply  13  from the first ply sheet  13 ′ by moving the cutter  45   a.  The cutting device (first cutting portion)  55  of the second forming unit  50  includes a cutter  55   a  capable of advancing and retreating in the width direction (Y direction) of the ply piece sheet  15 ′, and separates one ply piece  15  from the ply piece sheet  15 ′ by moving the cutter  55   a.    
     The holding rollers  46  and  56  are disposed between the cutting devices  45  and  55  and the forming drum  60 . Each of the holding rollers  46  and  56  is made from an elastic body such as sponge, and can be moved to an advance position in contact with the top of the forming drum  60  and a retracted position away from the forming drum  60  by an actuator (not shown). 
     The forming drum  60  is a cylindrical body that can be expanded and contracted around a rotating shaft  61 . The total length of the forming drum  60  from a base end  60   a  to a tip end  60   b  is larger than the width of the widest first ply sheet  13 ′ among the tire components wound around the forming drum  60 . 
     Referring to  FIGS. 2 and 3 , the forming drum  60  is rotatably attached to a support base  62 . The support base  62  includes a base portion  62   a  extending along the XY plane and a support portion  62   b  rising from one end of the base portion  62   a  along the XZ plane. An electric motor  63  is disposed inside the support portion  62   b.  The rotating shaft  61  is rotated counterclockwise in  FIG. 2  by the drive of the electric motor  63 , so that the forming drum  60  is integrally rotated. 
     As shown most clearly in  FIG. 3 , in the forming drum  60 , a region between positions P 1  and P 2  is a first forming region R 1  (third region) for forming the first ply  13 . In the forming drum  60 , a region between positions P 3  and P 4  is a second forming region R 2  (first region) for forming the first ply piece  15 . In the forming drum  60 , a region between positions P 5  and P 6  is a third forming region R 3  (second region) for forming the second ply piece  15 . In the forming drum  60 , a region between positions P 3  and P 5  is a region where the hollow portion  14   a  is formed. 
     One of a pair of the end portions  13   g  of the first ply  13  is located at the position P 1 , and the other one of a pair of the end portions  13   g  of the first ply  13  is located at the position P 2 . The inner end portion  15   a  of the first ply piece  15  is located at the position P 3 , and the outer end portion  15   g  of the first ply piece  15  is located at the position P 4 . The inner end portion  15   a  of the second ply piece  15  is located at the position P 5 , and the outer end portion  15   g  of the second ply piece  15  is located at the position P 6 . 
     Referring to  FIGS. 1 and 2 , the moving mechanism  70  relatively moves the servicer  41  and the forming drum  60  for the first ply sheet  13 ′, and relatively moves the servicer  51  and the forming drum  60  for the ply piece sheet  15 ′. In the present embodiment, the servicers  41  and  51  of the forming units  40  and  50  are fixed at fixed positions, and the moving mechanism  70  moves only the forming drum  60  in the axial direction (Y direction) of the forming drum  60 . 
     The moving mechanism  70  includes a conveyance path  71  that is laid to extend in the Y direction in which the first forming unit  40  and the second forming unit  50  are adjacent to each other, and a drive unit  72  that moves the forming drum  60  along the conveyance path  71 . In the present embodiment, the conveyance path  71  is composed of a pair of rails that are adjacent to the forming units  40  and  50  in the X direction and extend in parallel in the Y direction. The drive unit  72  includes four wheels  73  disposed at the bottom of the base portion  62   a  and an electric motor  74  disposed inside the base portion  62   a.  When the electric motor  74  rotates in the normal direction, the wheel  73  rotates in the normal direction, and the forming drum  60  moves to the right side in  FIG. 1  integrally with the support base  62 . When the electric motor  74  is reversed, the wheel  73  is reversed, and the forming drum  60  moves to the left side in  FIG. 1  integrally with the support base  62 . 
     The first forming unit  40 , the second forming unit  50 , the forming drum  60 , and the moving mechanism  70  are controlled by a control device (control unit)  80 . Specifically, as shown in  FIG. 4 , the control device  80  is electrically connected to the unwinding rollers  42  and  52 , the cutting devices  45  and  55 , the holding rollers  46  and  56 , the electric motor  63  for rotating the forming drum  60 , and the electric motor  74  for moving the forming drum  60 . 
     The control device  80  is composed of a well-known computer including a CPU, a memory, a storage device, and an input/output device, and software implemented in the computer. A storage unit  81  stores reference data of all the tire components wound around the forming drum  60 . The reference data includes the position in the drum axial direction (forming positions Mp 1  to Mp 3 ) at which the sheets  13 ′ and  15 ′ are wound around the forming drum  60 , total lengths of the first ply  13  and the ply piece  15  corresponding to the length in the drum circumferential direction, and the like. 
     The control device  80  controls the moving mechanism  70  based on a detection result of a position detection unit  75  that detects the position of the forming drum  60 , and disposes the forming drum  60  at the predetermined forming positions Mp 1  to Mp 3 . For the position detection unit  75 , a system including a transmission unit that wirelessly transmits signals of indoor messaging system (IMES) positioning, Wi-Fi positioning, beacon positioning, and the like and a positioning unit that measures a position based on a received signal can be used. However, the position detection unit  75  can be changed as necessary as long as the unit has a configuration that can detect the position of the forming drum  60 . 
     Specifically, the storage unit  81  stores position information of the first forming position Mp 1  (third position) for forming the first ply  13 , the second forming position Mp 2  (first position) for forming the first ply piece  15 , and the third forming position Mp 3  (second position) for forming the second ply piece  15 . 
     As shown by the alternate long and short dash line in  FIG. 1  and  FIGS. 5A and 5B , the first forming position Mp 1  is a position where the center C 1  of the first forming region R 1  of the forming drum  60  and the center of the guide  44  of the first forming unit  40  face each other in the Y direction. As shown by the solid line in  FIG. 1  and  FIGS. 6A and 6B , the second forming position Mp 2  is a position where the center C 2  of the second forming region R 2  of the forming drum  60  and the center of the guide  54  of the second forming unit  50  face each other in the Y direction. As shown by the broken line in  FIG. 1  and  FIGS. 7A and 7B , the third forming position Mp 3  is a position where the center C 3  of the third forming region R 3  of the forming drum  60  and the center of the guide  54  of the second forming unit  50  face each other in the Y direction. 
     The control device  80  moves the forming drum  60  by the moving mechanism  70  in the order of the first forming position Mp 1 , the second forming position Mp 2 , and the third forming position Mp 3  based on the position information stored in the storage unit  81  and the detection result of the position detection unit  75 . That is, the forming drum  60  is moved by the moving mechanism  70  so that the position information of the first forming position Mp 1  and the detection result of the position detection unit  75  match each other. Subsequently, the forming drum  60  is moved by the moving mechanism  70  so that the position information of the second forming position Mp 2  and the detection result of the position detection unit  75  match each other. Subsequently, the forming drum  60  is moved by the moving mechanism  70  so that the position information of the third forming position Mp 3  and the detection result of the position detection unit  75  match each other. 
     Further, the control device  80  controls the forming drum  60  based on a detection result of a posture detection unit  64  that detects the rotation angle position (posture) of the forming drum  60 , and also controls the first forming unit  40  and the second forming unit  50  individually. For the posture detection unit  64 , a detection mechanism or the like that detects a specific position of the rotating shaft  61  or the forming drum  60  itself by a limit switch can be used. However, the position detection unit  75  can be changed as necessary as long as the unit has a configuration that can detect the rotation angle position of the forming drum  60 . 
     At the forming positions Mp 1  to Mp 3 , the control device  80  controls the rotation of the forming drum  60  and the corresponding forming units  40  and  50  based on the detection result of the posture detection unit  64 . 
     In a state where the forming drum  60  is located at the predetermined rotation angle position, the unwinding rollers  42  and  52  are rotated, and the holding rollers  46  and  56  at the retracted position are caused to advance. In this manner, tip ends (start ends  13   h  and  15   h ) of the sheets  13 ′ and  15 ′ are crimped to the forming drum  60  by the holding rollers  46  and  56 . By rotating the forming drum  60  in this state, the sheets  13 ′ and  15 ′ are wound around the outer circumference of the forming drum  60 . 
     Subsequently, when the forming drum  60  is rotated to a predetermined angle position, the cutting devices  45  and  55  are driven, and then rotation of the unwinding rollers  42  and  52  is stopped after the sheets  13 ′ and  15 ′ are cut. Further, when cutting edges (terminations  13   i  and  15   i ) pass through the holding rollers  46  and  56 , the holding rollers  46  and  56  are retracted and the rotation of the forming drum  60  is stopped. 
     As shown in  FIG. 8 , the first ply  13  is formed in the first forming region R 1  of the forming drum  60  in a state where a part on the start end  13   h  side and a part on the termination  13   i  side overlap each other. Further, the first ply piece  15  is formed in the second forming region R 2  in a state where a part on the start end  15   h  side and a part on the termination  15   i  side overlap each other, and the second ply piece  15  is formed in the third forming region R 3  in a state where a part on the start end  15   h  side and a part on the termination  15   i  side overlap each other. 
     Subsequently, referring to  FIG. 8 , when viewed from the axial direction of the forming drum  60 , the control device  80  of the present embodiment makes the rotation angle position of the start end  15   h  of the ply piece sheet  15 ′ wound around the forming drum  60  different between one and the other one of a pair of the ply pieces  15 . That is, between a pair of the ply pieces  15 , overlap regions  15   j  of the start end  15   h  side and the termination  15   i  side are different in the tire circumferential direction. Further, these positions are different from an overlap region  10   a  of the inner liner  10  and an overlap region  13   j  of the first ply  13  in the tire circumferential direction. 
     Next, an example of ply forming treatment by the control device  80  will be described with reference to  FIG. 9 . 
     As shown in  FIG. 9 , when the forming of the strip rubber  9  has been completed in Step S 1 , the control device  80  controls the moving mechanism  70  based on the detection result of the position detection unit  75  to move the forming drum  60  to the first forming position Mp 1  in Step S 2 . Subsequently, in Step S 3 , the control device  80  controls the first forming unit  40  and the forming drum  60  based on the detection result of the posture detection unit  64 , so that the first ply sheet  13 ′ (first ply  13 ) is wound around the forming drum  60 . 
     When the forming of the first ply  13  has been completed, in Step S 4 , the control device  80  controls the moving mechanism  70  based on the detection result of the position detection unit  75  to move the forming drum  60  to the second forming position Mp 2 . Subsequently, in Step S 5 , the control device  80  controls the second forming unit  50  and the forming drum  60  based on the detection result of the posture detection unit  64 , so that the ply piece sheet  15 ′ (first ply piece  15 ) is wound around the forming drum  60 . 
     When the forming of the first ply piece  15  is completed, in Step S 6 , the control device  80  controls the moving mechanism  70  based on the detection result of the position detection unit  75  to move the forming drum  60  to the third forming position Mp 3 . Subsequently, in Step S 7 , the control device  80  controls the second forming unit  50  and the forming drum  60  based on the detection result of the posture detection unit  64 , so that the ply piece sheet  15 ′ (second ply piece  15 ) is wound around the forming drum  60 . 
     When the forming of the second ply piece  15  is completed, in Step S 8 , the control device  80  controls the moving mechanism  70  based on the detection result of the position detection unit  75  to move the forming drum  60  to the forming position of the inner liner  10 , and the treatment returns to Step S 1 . However, the first ply piece  15  and the second ply piece  15  may be formed in the reverse order. 
     The forming device  30  of the present embodiment configured as described above has a feature described below. 
     The moving mechanism  70  that relatively moves the servicer  51  and the forming drum  60  to the second forming position Mp 2  for forming one of a pair of the ply pieces  15  and the third forming position Mp 3  for forming the other one of a pair of the ply pieces  15  is included. Therefore, a pair of the ply pieces  15  can be formed with one servicer  51 . That is, in the forming device  30  which normally requires two servicers, only one servicer  51  needs to be installed. Therefore, as compared with the case where two servicers are disposed, the installation space of the forming device  30  for the green tire  1  including the second ply  14  having the hollow portion  14   a  can be reduced. 
     Each of a pair of the ply pieces  15  constituting the green tire  1  is formed by one ply piece sheet  15 ′ (cloth). Since there is substantially no width variation in one ply piece sheet  15 ′, the rubber volume on both sides in the tire width direction of the green tire  1  can be made uniform. 
     Further, since one and the other one of a pair of the ply pieces  15  are wound separately, the rotation angle position of the start end  15   h  to be wound around the forming drum  60  can be easily adjusted. That is, the overlap regions  15   j  of a pair of the ply pieces  15  can be disposed at different positions in the tire circumferential direction so that the overlap regions  15   j  are not concentrated on a part in the circumferential direction. Therefore, the uniformity of the completed pneumatic tire can be improved. 
     The moving mechanism  70  moves only the forming drum  60 . In this case, the moving mechanism  70  of the existing forming facility for forming the green tire  1  by winding the tire components around the forming drum  60  that has been moved sequentially can be used. Therefore, by modifying the existing forming facility, it is possible to easily realize the forming device  30  that forms a pair of the ply pieces  15  with one servicer  51 . 
     When viewed from the axial direction of the forming drum  60 , the rotation angle position of the start end  15   h  of the ply piece sheet  15 ′ wound around the forming drum  60  is made different between one and the other one of a pair of the ply pieces  15 . Therefore, it is possible to prevent the overlap regions  15   j,  in which the rubber volume is locally increased, from concentrating on a part in the circumferential direction, so that the uniformity of the completed pneumatic tire can be improved. 
     (Second Embodiment) 
       FIG. 10  shows the ply forming unit  31  of the forming device  30  of a second embodiment. This forming device  30  is different from the forming device  30  of the first embodiment in that a third forming unit  90  for forming the ply pieces  15  of different types is added. 
     The third forming unit  90  is disposed on the side opposite to the first forming unit  40  with respect to the second forming unit  50 , and is adjacent to the second forming unit  50  in the Y direction. The third forming unit  90  includes one servicer (third servicer)  91  for sending out a strip-shaped ply piece sheet (third sheet)  15 ″ for forming a plurality of the ply pieces  15 . The configuration of the servicer  91  is similar to that of the servicer  51  shown in  FIG. 2 . That is, the servicer  91  includes a pair of unwinding rollers, a conveyor, a guide, a cutting device (third cutting portion), and a holding roller. 
     The ply piece sheet  15 ″ which is different from the ply piece sheet  15 ′ set in the second forming unit  50  is set in the third forming unit  90 . The ply piece sheet  15 ′ of the second forming unit  50  and the ply piece sheet  15 ″ of the third forming unit  90  differ in at least one of the width in the Y direction, the rubber material, and the number of cords. Therefore, the pneumatic tire including the ply piece  15  composed of the ply piece sheet  15 ′ and the pneumatic tire including the ply piece  15  composed of the ply piece sheet  15 ″, which have the same appearance and cross-sectional shape, have different rigidity (contributing to improvement in the steering stability) and cut resistance for the sidewall portion  3 . 
     The control device  80  (see  FIG. 4 ) of the second embodiment selectively drives only one of the second forming unit  50  and the third forming unit  90  according to the instruction of the operator. That is, in a case where the second forming unit  50  is selected, the third forming unit  90  is not driven. Further, in a case where the third forming unit  90  is selected, the second forming unit  50  is not driven. The control in a case where the third forming unit  90  is selected is the same as the control of the second forming unit  50 . While one of the second forming unit  50  and the third forming unit  90  is used to manufacture the green tire  1 , the operator can switch to use the other one to manufacture the green tire  1 . 
     The forming device  30  of the second embodiment configured in this way can obtain an action and an effect similar to those of the first embodiment. Moreover, since the ply piece sheets  15 ′ and  15 ″ of different types can be disposed in one forming device  30 , the time required for switching a production line can be shortened when pneumatic tires with the second plies  14  of different types is manufactured. 
     Note that the forming device  30  for the green tire  1  of the present invention is not limited to the configuration of the above embodiment, and various changes can be made. 
     For example, three or more forming units for the ply pieces  15  may be disposed in order to form the ply pieces  15  of different types. 
     The first forming unit  40  may be eliminated, and the carcass  12  of the green tire  1  may be formed only with the second ply  14  having the hollow portion  14   a.  In order to provide two or more of the second plies  14  having the hollow portion  14   a,  the forming drum  60  may be repeatedly moved to the second forming position Mp 2  and the third forming position Mp 3  by the moving mechanism  70 . 
     The moving mechanism  70  may move the servicers  41  and  51  by fixing the forming drum  60  to a fixed position, or may move all of the servicers  41  and  51  and the forming drum  60 . Further, the moving mechanism  70  can be changed as necessary as long as the moving mechanism  70  is configured to be able to relatively move the first forming unit  40 , the second forming portion  50 , and the forming drum  60 .