Patent Publication Number: US-2021178715-A1

Title: Forming device and forming method for green tire

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority of Japanese Patent Application No. 2019-225703 filed on Dec. 13, 2019, the contents of which are incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     Technical Field 
     The present invention relates to a forming device and a forming method for a green tire. 
     Related Art 
     A carcass ply of a pneumatic tire disclosed in JP 2017-109517 A includes a first ply that is continuous between a pair of bead portions and a discontinuous second ply that is disposed on the outer side in the tire radial direction of the first ply. The second ply includes a pair of ply pieces extending from a tread portion to a pair of the bead portions, respectively. 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 OF THE INVENTION 
     The pneumatic tire of JP 2017-109517 A is manufactured by vulcanizing a green tire including a discontinuous carcass ply having a pair of ply pieces. However, JP 2017-109517 A does not disclose a forming device and a forming method for efficiently forming such a green tire. 
     An object of the present invention is to provide a green tire forming device and a forming method capable of efficiently forming a green tire including a discontinuous carcass ply having a pair of ply pieces. 
     One aspect of the present invention provides a forming device for a green tire including a discontinuous carcass ply having a pair of ply pieces. The forming device includes a supply unit that supplies a strip-shaped ply sheet for forming the discontinuous carcass ply, a dividing portion that divides, in front in a feed direction of the ply sheet, the ply sheet supplied from the supply unit into two in a direction orthogonal to the feed direction, a guide portion that guides the ply sheets divided into two by the dividing portion so that the ply sheets are separated from each other in a direction orthogonal to the feed direction, a cutting portion that cuts the ply sheets divided into two by the dividing portion in the feed direction to separate the pair of ply pieces from the ply sheets, and a forming drum that winds up the pair of ply pieces that are separated by the cutting portion and are separated from each other in a direction orthogonal to the feed direction. 
     If a pair of ply pieces are wound around a forming drum by using one supply unit that supplies one ply piece, it is necessary to wind one of a pair of ply pieces and the other around the forming drum in order, and a green tire cannot be manufactured efficiently. In contrast, according to the present configuration, a ply sheet supplied from one supply unit is divided and cut, so that a pair of ply pieces can be wound around the forming drum at once, and a green tire can be efficiently manufactured. 
     Further, if a pair of ply pieces are wound around a forming drum at once by using two supply units, each of which supplying one ply piece, it is necessary to prepare a ply piece for each of the two supply units, and a green tire cannot be manufactured efficiently. In contrast, according to the present configuration, a ply sheet supplied from one supply unit is divided and cut, so that a pair of ply pieces are supplied to the forming drum at once. Accordingly, as long as a ply sheet is prepared in one supply unit, it is not necessary to prepare each of a pair of ply pieces separately. In this manner, a green tire can be efficiently manufactured. 
     Further, since a pair of ply pieces are formed by dividing and cutting one ply sheet, uniformity of a pair of the ply pieces can be improved as compared with the case where a pair of ply pieces are manufactured separately. 
     Another aspect of the present invention provides a forming method for a green tire including a discontinuous carcass ply having a pair of ply pieces. The forming method includes supplying a ply sheet for forming the carcass ply, dividing the ply sheet into two in a direction orthogonal to a feed direction, feeding the ply sheets divided into two to front in the feed direction so that the ply sheets divided into two are gradually separated in a direction orthogonal to the feed direction, cutting the ply sheets divided into two in the feed direction to separate the pair of ply pieces from the ply sheet, and winding, around a forming drum, the pair of ply pieces. 
     According to the present invention, a green tire including a discontinuous carcass ply having a pair of ply pieces can be efficiently formed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of the present invention will be apparent from the following description and the drawings of exemplary embodiments of the present invention. In the drawings, where: 
         FIG. 1  is a meridian cross-sectional view of a green tire according to an embodiment of the present invention; 
         FIG. 2  is a cross-sectional view of a tread portion of the green tire and its periphery according to the embodiment; 
         FIG. 3  is a perspective view showing a schematic configuration of a forming device for the green tire according to the embodiment; 
         FIG. 4  is a side view of a second forming unit of the forming device of  FIG. 3 ; 
         FIG. 5  is a perspective view similar to  FIG. 3  showing a schematic configuration of a forming device for a green tire according to a first comparative example; and 
         FIG. 6  is a perspective view similar to  FIG. 3  showing a schematic configuration of a forming device for a green tire according to a second comparative example. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 
       FIG. 1  is a meridian cross-sectional view of a green tire  1  according to the present embodiment. By vulcanizing the green tire  1  with a vulcanization device (not shown), a pneumatic tire made from rubber is manufactured. 
     As shown in  FIG. 1 , 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 a tire width direction (indicated by the reference character TW in  FIG. 1 ). The pneumatic tire manufactured by vulcanizing the green tire  1  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 end of the tread portion  2  to the inner side in the tire radial direction (reference character TR in  FIG. 1 ). 
     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 to the outer side in the tire radial direction from the base end  8   a  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”)  13  and a second carcass ply (hereinafter, referred to as “second ply”)  14 . 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  13  and the second ply  14  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 . 
       FIG. 2  is a cross-sectional view of the tread portion  2  of the green tire  1  and its periphery according to the present embodiment. 
     Referring to  FIG. 2 , an endless belt layer  18  is provided between the tread rubber  5  and the carcass  12  (first ply  13  and second ply  14 ). 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 on the outer side in the tire width direction of 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 outer ends 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 outer end portion  23   a  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 outer end portion  26   a  and an inner end portion  26   b  in the tire width direction of the pad  26 , 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. 1 and 2 , the first ply  13  is a single ply, while the second ply  14  is a discontinuous carcass 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 on the inner side in the tire width direction of the bead portion  4  (that is, the bead core  7  and the bead filler  8 ) with the ply piece  15  interposed between the inner portion  13   d  and the bead portion  4 . 
     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 on the outer side in the tire width direction of 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 on the outer side in the tire radial direction of the tip end  8   b  of the bead filler  8  and is positioned on the inner side in the tire radial direction of 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 outer region in the tire width direction of the tread portion  2 , more specifically, in the region on the inner side in the tire width direction of 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 on the outer side in the tire radial direction of 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 on the outer side in the tire radial direction of the tip end  8   b  of the bead filler  8  and is positioned on the inner side in the tire radial direction of the tread portion  2 , more specifically, on the inner side in the tire radial direction of 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 , the edge ply  23 , and the cap ply  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 edge ply  23 , the cap ply  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 through the fourth forming step. 
     (Forming Device for Green Tire) 
       FIG. 3  shows a first forming device  30  that performs the first forming step. Specifically,  FIG. 3  shows a ply forming unit of the forming device  30  for forming the first ply  13  and a pair of the ply pieces  15  (shown in  FIG. 1 ). 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  (shown in  FIG. 1 ) is similar to the conventional one, and will be omitted from the detailed description. Similarly, the configurations other than the first forming device  30  are similar to those in the prior art, and will be omitted from the detailed description. 
     As shown in  FIG. 3 , the ply forming unit of the forming device  30  includes a first forming unit  31  for forming the first ply  13  (shown in  FIG. 1 ) and a second forming unit  32  for forming the second ply  14  (shown in  FIG. 1 ). Further, the ply forming unit of the forming device  30  includes one forming drum  60  and a moving mechanism  70  (shown in  FIG. 4 ) 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  31  and the second forming unit  32  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  31  and the second forming unit  32  are disposed adjacent to each other in the Y direction (axial direction) in which an axis A of the forming drum  60  extends. 
     The first forming unit  31  includes a first servicer  40  for sending out a strip-shaped first ply sheet  13 ′ for forming the first ply  13  (shown in  FIG. 1 ) and a supply unit (not shown) for supplying the first ply sheet  13 ′ to the first servicer  40 . 
     The first servicer  40  is disposed above the top of the forming drum  60 , and supplies the first ply sheet  13 ′ to the forming drum  60  from above. The dimension (width) in the Y direction of the first ply sheet  13 ′ corresponds to the width of the first ply  13  from one of a pair of the end portions  13   g  (shown in  FIG. 1 ) to the other. 
     The first servicer  40  includes a guide  41  for guiding the first ply sheet  13 ′ and a cutting portion  42  disposed between the guide  41  and the forming drum  60 . The first ply sheet  13 ′ is supplied to the guide  41  of the first servicer  40  from the supply unit (not shown). The first ply sheet  13 ′ sent out toward the forming drum  60  by the guide  41  is cut to a predetermined length by the cutting portion  42 , and the first ply  13  (shown in  FIG. 1 ) is separated from the first ply sheet  13 ′. 
     The second forming unit  32  includes a second servicer  50  that sends out a strip-shaped second ply sheet  15 ′ for forming a pair of the ply pieces  15  (shown in  FIG. 1 ). The second ply sheet  15 ′ of the present embodiment is an example of the ply sheet according to the present invention. 
     The second servicer  50  is disposed above the top of the forming drum  60 , and supplies the second ply sheet  15 ′ divided into two to the forming drum  60  from above. In this manner, the second forming unit  32  forms both of a pair of the ply pieces  15  at the same time. In the description below, of a pair of the ply pieces  15 , the one positioned on the right side in  FIG. 2  may be referred to as a first ply piece  15 A, and the one positioned on the left side in  FIG. 2  may be referred to as a second ply piece  15 B. 
       FIG. 4  is a side view of the second forming unit  32  of the forming device  30 . 
     Referring to  FIG. 4 , the second forming unit  32  of the forming device  30  of the present embodiment includes an unwinding device  80  that supplies the second ply sheet  15 ′ to the second servicer  50 . The unwinding device  80  according to the present embodiment is an example of the supply unit according to the present invention. 
     The unwinding device  80  includes a shaft portion  81  around which the second ply sheet  15 ′ is wound, a frame body  82  having a size surrounding the wound second ply sheet  15 ′, and a moving roller  83  attached to a lower part of the frame body  82 . Further, the unwinding device  80  includes an electric motor  84 , which is connected to the shaft portion  81  and rotationally drives the shaft portion  81 . The shaft portion  81  is rotatably supported by the frame body  82 . The shaft portion  81  is rotated counterclockwise in  FIG. 4  by the electric motor  84 , so that the second ply sheet  15 ′ is unwound toward the second servicer  50 . 
     The second servicer  50  includes a pair of first conveyance rollers  51  that convey the second ply sheet  15 ′ supplied from the unwinding device  80  forward in the feed direction (X direction), a dividing portion  52 , and two pairs of second conveyance rollers  53  (only one is shown in  FIG. 4 ). Further, the second servicer  50  includes two conveyors  54  (only one is shown in  FIG. 4 ), a guide  55 , two cutting portions  56  (only one is shown in  FIG. 4 ), and two holding rollers  57  (only one is shown in  FIG. 4 ). 
     A pair of the first conveyance rollers  51  are rotated by an electric motor (not shown). Of a pair of the first conveyance rollers  51 , the one positioned on the upper side rotates clockwise in  FIG. 4 , and the one positioned on the lower side rotates counterclockwise in  FIG. 2 . The second ply sheet  15 ′ is supplied from the unwinding device  80  to a pair of the first conveyance rollers  51 . The first conveyance roller  51  conveys the second ply sheet  15 ′ supplied from the unwinding device  80  forward in the feed direction (X direction). 
     A first dancer roll  58  capable of linearly moving in the vertical direction (Z direction) is provided between the unwinding device  80  and a pair of the first conveyance rollers  51 . The first dancer roll  58  absorbs a difference between a feed amount of the second ply sheet  15 ′ supplied from the unwinding device  80  and a feed amount of the second ply sheet  15 ′ fed forward in the feed direction by the first conveyance roller  51 . 
     The dividing portion  52  is provided in front of the first conveyance roller  51  in the feed direction. The second ply sheet  15 ′ is supplied to the dividing portion  52  from the first conveyance roller  51 . The dividing portion  52  divides the second ply sheet  15 ′ in two in a direction (Y direction) orthogonal to the feed direction. In this manner, the second ply sheet  15 ′ is divided into two in front of the dividing portion  52  in the feed direction. In the description below, one of the two divided second ply sheets  15 ′ may be referred to as a first ply piece sheet  15 A′, and the other of the two divided second ply sheets  15 ′ may be referred to as the second ply piece sheet  15 B′. The dividing portion  52  of the present embodiment is a round blade that is rotationally driven by an electric motor (not shown). 
     A pair of the second conveyance rollers  53  are provided in front of the dividing portion  52  in the feed direction. A pair of the second conveyance rollers  53  are rotated by an electric motor (not shown). Of a pair of the second conveyance rollers  53 , the one positioned on the upper side rotates clockwise in  FIG. 4 , and the one positioned on the lower side rotates counterclockwise in  FIG. 4 . The first ply piece sheet  15 A′ and the second ply piece sheet  158 ′ divided by the dividing portion  52  are supplied to two pairs of the second conveyance rollers  53 , respectively. One of two pairs of the second conveyance rollers  53  conveys the first ply piece sheet  15 A′ forward in the feed direction (X direction). The other of two pairs of the second conveyance rollers  53  conveys the second ply piece sheet  15 B′ forward in the feed direction (X direction). 
     The two conveyors  54  are disposed between two pairs of the second conveyance rollers  53  and the forming drum  60 . Each of the conveyors  54  is composed of a roller conveyor including a plurality of rollers disposed at intervals in the feed direction (X direction) of the second ply sheet  15 ′. The individual rollers extend in the width direction (Y direction) of the second ply sheet  15 ′. One of the two conveyors  54  conveys the first ply piece sheet  15 A′ forward in the feed direction (X direction), and the other of the two conveyors  54  conveys the second ply piece sheet  15 B′ forward in the feed direction (in the X direction). 
     Between a pair of the second conveyance rollers  53  and the conveyor  54 , two second dancer rolls  59  capable of linearly moving in the vertical direction (Z direction) are provided. The first ply piece sheet  15 A′ is hung on one of the two second dancer rolls  59 , and the second ply piece sheet  158 ′ is hung on the other of the two second dancer rolls  59 . One of the two second dancer rolls  59  absorbs a difference between a feed amount of the first ply piece sheet  15 A′ fed forward in the feed direction by the second conveyance roller  53  and a feed amount of the first ply piece sheet  15 A′ fed forward in the feed direction by the conveyor  54 . The other of the two second dancer rolls  59  absorbs a difference between a feed amount of the second ply piece sheet  15 B′ fed forward in the feed direction by the second conveyance roller  53  and a feed amount of the second ply piece sheet  15 B′ fed forward in the feed direction by the conveyor  54 . 
     The guide  55  is disposed between the two conveyors  54  and the forming drum  60 . As most clearly shown in  FIG. 3 , the guide  55  is a square tubular frame body that determines the position for feeding the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′. The guide  55  includes outlets  55   a  and  55   b  having a size by which the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′ can be sent out. The outlets  55   a  and  55   b  are disposed apart from each other in a direction (Y direction) orthogonal to the feed direction (X direction). The guide  55  of the present embodiment is an example of the guide portion of the present invention. 
     The two cutting portions  56  are disposed between the guide  55  and the forming drum  60 . Referring to  FIG. 3 , each of the two cutting portions  56  includes a cutter  56   a  capable of advancing and retreating in the width direction (Y direction) of the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′. The movement of each of the cutters  56   a  separates the first ply piece  15 A (shown in  FIG. 2 ) from the first ply piece sheet  15 A′ and the second ply piece  15 B (shown in  FIG. 2 ) from the second ply piece sheet  15 B′. 
     Referring to  FIG. 4 , the two holding rollers  57  are disposed between each of the cutting portions  56  and the forming drum  60 . Each of the two holding rollers  57  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 . Referring to  FIG. 3 , 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  FIG. 4 , 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. 4  by the drive of the electric motor  63 , so that the forming drum  60  is integrally rotated. 
     The moving mechanism  70  moves the forming drum  60  relative to the first servicer  40  used for the first ply sheet  13 ′, and moves the forming drum  60  relative to the second servicer  50  used for the second ply sheet  15 ′. In the present embodiment, the first servicer  40  of the first forming unit  31  and the second servicer  50  of the second forming unit  32  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  31  and the second forming unit  32  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 first forming unit  31  (shown in  FIG. 3 ) and the second forming unit  32  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. 3  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. 3  integrally with the support base  62 . 
     The first forming unit  31 , the second forming unit  32 , the forming drum  60 , the moving mechanism  70 , and the unwinding device  80  are controlled by a control device (not shown). Specifically, the control device is electrically connected to an electric motor  84  of the unwinding device  90 , electric motors (not shown) for driving the first conveyance roller  51 , the dividing portion  52 , and the second conveyance roller  53 , the cutting portions  42  and  56 , the holding roller  57 , the electric motor  63  that rotates the forming drum  60 , and the electric motor  74  of the moving mechanism  70  for moving the forming drum  60 . The control device 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. 
     (Forming of Second Ply) 
     In the present embodiment, the discontinuous second ply  14  is formed as a pair of the ply pieces  15  are wound at once around the forming drum  60  around which the inner liner  10 , the strip rubber  9 , and the first ply  13  are wound. Hereinafter, a forming method for the discontinuous second ply  14  of the present embodiment will be described. 
     Referring to  FIGS. 3 and 4 , first, the unwinding device  80 , the first conveyance roller  51 , the second conveyance roller  53 , and the conveyor  54  are driven to convey the second ply sheet  15 ′ of the unwinding device  80  toward the forming drum  60 . At this time, the second ply sheet  15 ′ is divided into two in front of the dividing portion  52  in the feed direction. Specifically, the second ply sheet  15 ′ is divided into the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′ in front of the dividing portion  52  in the feed direction. 
     As is clearly shown in  FIG. 3 , the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′ are sent so as to be gradually separated from each other toward the front in the feed direction in front of the dividing portion  52  in the feed direction. 
     At this time, by adjusting the feed amount of the second ply sheet  15 ′ of the first conveyance roller  51  and the feed amounts of the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′ of the second conveyance roller  53 , the second ply sheet  15 ′ can be maintained in a stretched state in the dividing portion  52 . In this manner, the second ply sheet  15 ′ can be easily divided by the dividing portion  52 . 
     Next, when the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′ are sent out from the outlets  55   a  and  55   b  of the guide  55  and advance to the upper part of the forming drum  60  in a state of being separated from each other in the Y direction, the holding roller  57  at the retracted position is moved to an advanced position. In this manner, the tip ends of the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′ are crimped to the forming drum  60  by the holding roller  57 . 
     After that, by rotating the forming drum  60 , the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′ are wound around the outer peripheral surface of the forming drum  60 . 
     Subsequently, when the forming drum  60  rotates to a predetermined angle position, the cutting portion  56  is driven to separate a pair of the ply pieces  15  (the first ply piece  15 A and the second ply piece  15 B) from the first ply piece sheet  15 A′ and the second ply piece sheet  15 B′. After that, the unwinding device  80 , the first conveyance roller  51 , the second conveyance roller  53 , and the conveyor  54  are stopped. Further, when the cutting edges of the first ply piece sheet  15 A′ and the second ply piece sheet  158 ′ pass through the holding roller  57 , the holding roller  57  is moved to the retracted position and the rotation of the forming drum  60  is stopped. 
     First Comparative Example 
       FIG. 5  is a schematic perspective view similar to  FIG. 3  showing a schematic configuration of a ply forming unit of a forming device  130  according to a first comparative example. The forming device  130  according to the first comparative example has a configuration similar to that of the forming device  30  according to the embodiment of the present invention, except for a second forming unit  132 . In the first comparative example, configurations similar to those of the embodiment of the present invention are designated by the same reference numerals, and omitted from detailed description. 
     Referring to  FIG. 5 , the second forming unit  132  according to the first comparative example includes one second servicer  150  that sends out a ply piece sheet  115 ′ for forming the ply piece  15 . The second servicer  150  according to the first comparative example includes one guide  155  having one outlet  155   a . The ply piece sheet  115 ′ is supplied to the guide  155  from one unwinding device (not shown). The ply piece sheet  115 ′ according to a first comparative example has a configuration similar to that of the ply piece sheets  15 A′ and  15 B′ according to the embodiment. 
     In the first comparative example, after forming the inner liner  10 , the strip rubber  9 , and the first ply  13 , one of a pair of the ply pieces  15  and the other are formed in order. 
     Specifically, first, the ply piece sheet  115 ′ sent out from the guide  155  is wound around the forming drum  60  on which the first ply  13  is wound by the first forming unit  31 , so that one of a pair of the ply pieces  15  is formed. After that, the forming drum  60  is moved in the Y direction, and the ply piece sheet  115 ′ sent out from the guide  155  is wound around the forming drum  60 , so that the other of a pair of the ply pieces  15  is formed. 
     Second Comparative Example 
       FIG. 6  is a schematic perspective view similar to  FIG. 3  showing a schematic configuration of a ply forming unit of a forming device  230  according to a second comparative example. The forming device  230  according to the second comparative example has a configuration similar to that of the forming device  30  according to the embodiment of the present invention, except for a second forming unit  232 . In the second comparative example, configurations similar to those of the embodiment of the present invention are designated by the same reference numerals, and omitted from detailed description. 
     Referring to  FIG. 6 , the second forming unit  232  according to the second comparative example includes two unwinding devices (not shown). In the second comparative example, the guide  55  of a second servicer  250  is supplied with a ply piece sheet  215 ′ from each of the two unwinding devices. In the second comparative example, the ply piece sheet  215 ′ supplied from one of the two unwinding devices is sent out from the outlet  55   a  of the guide  55 , and the ply piece sheet  215 ′ supplied from the other of the two unwinding devices is sent out from the outlet  55   b  of the guide  55 . The ply piece sheet  215 ′ according to a second comparative example has a configuration similar to that of the ply piece sheets  15 A′ and  15 B′ according to the embodiment. 
     In the second variation, a pair of the ply pieces  15  are formed at one time by the second forming unit  232  as in the embodiment of the present invention. 
     According to the forming device and the forming method for the green tire  1  of the present embodiment, an action and an effect described below are achieved. 
     If, as in the first comparative example, a pair of the ply pieces  15  are wound around the forming drum  60  by using the one second servicer  150  that sends out the one ply piece sheet  115 ′, it is necessary to wind one of a pair of the ply pieces  15  and the other around the forming drum  60  in order, and the green tire  1  cannot be manufactured efficiently. In contrast, according to the present embodiment, the ply sheet  15 ′ supplied from the unwinding device  80  is divided and cut by the second servicer  50 , so that a pair of the ply piece sheets  15 A′ and  15 B′ for forming a pair of the ply pieces  15  can be sent out from the second servicer  50  at once. In this manner, a pair of the ply pieces  15  are formed by the forming drum  60  at once, so that the green tire  1  can be efficiently manufactured. 
     Further, if, as in the second comparative example, a pair of the ply pieces  15  are wound around the forming drum  60  at once by using two unwinding devices for supplying the one ply piece sheet  215 ′, it is necessary to prepare the ply piece sheet  215 ′ for each of the two unwinding devices, and the green tire  1  cannot be manufactured efficiently. In contrast, according to the present embodiment, the ply sheet  15 ′ supplied from the unwinding device  80  is divided and cut by the second servicer  50 , so that a pair of the ply piece sheets  15 A′ and  158 ′ for forming a pair of the ply pieces  15  can be sent out from the second servicer  50  at once. That is, as long as the ply sheet  15 ′ is prepared in the one unwinding device  80 , it is not necessary to prepare the ply piece sheet  215 ′ in each of the two unwinding devices separately. In this manner, the green tire  1  can be efficiently manufactured. 
     Further, since a pair of the ply pieces  15  are formed by dividing and cutting the one ply sheet  15 ′, uniformity of a pair of the ply pieces  15  can be improved as compared with the case where a pair of the ply pieces  15  are manufactured separately. 
     Further, since the first conveyance roller  51  is provided in front of the dividing portion  52  in the feed direction and the second conveyance roller  53  is provided behind the dividing portion  52  in the feed direction, by adjusting the feed amount of the first conveyance roller  51  and the feed amount of the second conveyance roller  53 , the tension of the second ply sheet  15 ′ at the dividing portion  52  is adjusted. That is, the second servicer  50  of the present embodiment has a tension control mechanism for adjusting the tension of the second ply sheet  15 ′ in the dividing portion  52 . In this manner, the state in which the second ply sheet  15 ′ is stretched can be easily maintained in the dividing portion  52 , and the second ply sheet  15 ′ can be easily divided by the dividing portion  52 . 
     Further, according to the forming method for the green tire  1  according to the present embodiment, the green tire  1  can be efficiently formed as described above. 
     For example, in the embodiment, the first forming unit  31  and the second forming unit  32  are disposed adjacent to each other in the Y direction. However, the present invention is not limited to this, and the first forming unit  31  and the second forming unit  32  may be disposed side by side in the Z direction (vertical direction). 
     For example, in the embodiment, the one guide  55  includes two outlets  55   a  and  55   b . However, the present invention is not limited to this, and the two outlets  55   a  and  55   b  may be provided in separate guides. 
     For example, in the embodiment, the dividing portion  52  is a round blade that is rotationally driven by an electric motor. However, the present invention is not limited to this, and the dividing portion  52  may be, for example, a saw blade that can move linearly in the vertical direction.