JP2013146932A - Method of manufacturing pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a pneumatic tire that can facilitate a manufacturing process of the tire that has the carcass divided structure.SOLUTION: A method for manufacturing a pneumatic tire 1 includes: a side member molding step ST11 to form a side member X that has a bead member (bead core and bead filler), a carcass layer, sidewall rubbers, rim cushion rubbers, and a side inner liner that composes a part of the inner liners; a belt tread assembly molding step ST12 that forms a belt tread assembly that has a belt layer and a tread rubber; and a shaping step ST13 to perform shaping by connecting a pair of side members and the belt tread assembly.

Description

  The present invention relates to a method for manufacturing a pneumatic tire, and more particularly, to a method for manufacturing a pneumatic tire that can facilitate a manufacturing process of a tire having a carcass division structure.

  In recent pneumatic tires, a carcass division structure in which a carcass layer is divided at a tread portion center region has been proposed.

  FIG. 27 is an explanatory view showing a method of manufacturing a conventional pneumatic tire having such a carcass division structure. The figure shows the molding process of the primary green tire.

  In a conventional pneumatic tire manufacturing method, first, a pair of bead cores 101, 101, a pair of bead fillers 102, 102, a pair of carcass layers 103, 103, and a single piece are formed on an axially expandable / contractible forming drum 100. The inner liner 104 having a structure is set (see FIG. 27). Then, the left and right carcass layers 103 are rolled up to form a cylindrical primary green tire X. Next, a belt-tread assembly having a belt layer and tread rubber is formed (not shown). Then, the primary green tire X and the belt / tread assembly are bonded together to form a secondary green tire (not shown). Thereafter, the secondary green tire is put into a molding die of a vulcanizer and vulcanized.

  As a conventional pneumatic tire manufacturing method employing such a configuration, a technique described in Patent Document 1 is known.

JP 2011-20350 A

  However, in the conventional pneumatic tire manufacturing method, when manufacturing tires of different sizes, it is necessary to change the axial length of the forming drum 100 (replacement operation) (see FIG. 27). For this reason, the work time required for the changing operation is long, and the forming drum 100 that can be changed is required.

  Therefore, the present invention has been made in view of the above, and an object of the present invention is to provide a method for manufacturing a pneumatic tire that can facilitate the manufacturing process of a tire having a carcass division structure.

  In order to achieve the above object, a manufacturing method of a pneumatic tire according to the present invention includes a pair of bead members, a pair of carcass layers, a belt layer, a tread rubber, a pair of sidewall rubbers, and a pair of rim cushions. A method of manufacturing a pneumatic tire comprising rubber and an inner liner, wherein the bead member, the carcass layer, the sidewall rubber, the rim cushion rubber, and a side inner liner constituting a part of the inner liner A side member molding step for molding a side member having a belt, a belt tread assembly molding step for molding a belt tread assembly having the belt layer and the tread rubber, and a pair of the side members and the belt tread assembly. A shaping step for joining and shaping a solid And wherein the door.

  The pneumatic tire manufacturing method according to the present invention includes a pair of bead members, a pair of carcass layers, a belt layer, a tread rubber, a pair of sidewall rubbers, a pair of rim cushion rubbers, and an inner liner. A side member forming step of forming a side member having a side inner liner that constitutes a part of the bead member, the carcass layer, and the inner liner, and the belt. Belt-tread assembly molding step for forming a belt-tread assembly having a layer and the tread rubber, a pair of the side members, the belt-tread assembly, a pair of the sidewall rubbers, and a pair of the rim cushion rubbers And a shaping step for joining and shaping And butterflies.

  In the pneumatic tire manufacturing method according to the present invention, the pneumatic tire includes the left and right carcass layers having a divided structure and the left and right side inner liners having the divided structure. The side members can be formed independently in a state where they are separated from each other. Thereby, compared with the manufacturing method of the pneumatic tire which an inner liner has a single structure, there exists an advantage which can simplify the manufacturing process of a tire, and there exists an advantage which can improve the quality of a tire. In addition, when manufacturing tires of different sizes, there is an advantage that the step of changing the axial length of the forming drum is not required, and the side member forming step can be simplified.

FIG. 1 is a sectional view in the tire meridian direction showing a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a flowchart showing a method for manufacturing the pneumatic tire shown in FIG. FIG. 3 is an explanatory view showing a method for manufacturing the pneumatic tire shown in FIG. 1. FIG. 4 is an explanatory view showing a method for manufacturing the pneumatic tire shown in FIG. 1. FIG. 5 is an explanatory view showing a method for manufacturing the pneumatic tire shown in FIG. 1. FIG. 6 is an explanatory diagram showing a method for manufacturing the pneumatic tire depicted in FIG. 1. FIG. 7 is an explanatory view showing a method for manufacturing the pneumatic tire shown in FIG. 1. FIG. 8 is an explanatory view showing a method for manufacturing the pneumatic tire shown in FIG. 1. FIG. 9 is an explanatory view showing the effect of the method for manufacturing the pneumatic tire shown in FIG. 1. FIG. 10 is an explanatory view showing an inner liner of the pneumatic tire shown in FIG. FIG. 11 is an explanatory view showing a modification of the inner liner shown in FIG. FIG. 12 is an explanatory view showing a modified example of the inner liner shown in FIG. FIG. 13 is an explanatory view showing a modification of the method for manufacturing the pneumatic tire shown in FIG. FIG. 14 is an explanatory view showing a modification of the manufacturing method of the pneumatic tire shown in FIG. FIG. 15 is an explanatory view showing a modified example of the manufacturing method of the pneumatic tire shown in FIG. FIG. 16 is an explanatory view showing a modified example of the manufacturing method of the pneumatic tire shown in FIG. FIG. 17 is an explanatory view showing a modification of the method for manufacturing the pneumatic tire shown in FIG. FIG. 18 is an explanatory view showing a modification of the method for manufacturing the pneumatic tire depicted in FIG. 2. FIG. 19 is an explanatory view showing a modification of the method for manufacturing the pneumatic tire shown in FIG. FIG. 20 is an explanatory diagram illustrating a modification of the pneumatic tire depicted in FIG. 1. FIG. 21 is an explanatory view showing a modified example of the pneumatic tire depicted in FIG. 1. FIG. 22 is an explanatory view showing a modified example of the pneumatic tire depicted in FIG. 1. FIG. 23 is an explanatory diagram illustrating a modification of the pneumatic tire depicted in FIG. 1. FIG. 24 is an explanatory diagram illustrating a modification of the pneumatic tire depicted in FIG. 1. FIG. 25 is an explanatory diagram illustrating a modification of the pneumatic tire depicted in FIG. 1. FIG. 26 is a chart showing results of performance tests of the pneumatic tire manufacturing method according to the embodiment of the present invention. FIG. 27 is an explanatory view showing a method of manufacturing a conventional pneumatic tire having such a carcass division structure.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Further, the constituent elements of this embodiment include those that can be replaced while maintaining the identity of the invention and that are obvious for replacement. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

[Pneumatic tire]
FIG. 1 is a sectional view in the tire meridian direction showing a pneumatic tire 1 according to an embodiment of the present invention. FIG. 1 shows a radial tire for a passenger car having a carcass division structure as an example of the pneumatic tire 1. Reference sign CL is a tire equator plane.

  The pneumatic tire 1 includes a pair of bead cores 11, 11, a pair of bead fillers 12, 12, a pair of carcass layers 13, 13, a belt layer 14, a tread rubber 15, a pair of sidewall rubbers 16, 16 and a pair of rim cushion rubbers 17 and 17 (see FIG. 1).

  The pair of bead cores 11 and 11 has an annular structure and constitutes the core of the left and right bead portions. The pair of bead fillers 12 and 12 are disposed on the outer periphery in the tire radial direction of the pair of bead cores 11 and 11 to reinforce the bead portion.

  The pair of carcass layers 13 and 13 has a two-layer structure formed by laminating two carcass plies 131 and 132, respectively, and is arranged from the left and right bead cores 11 and 11 to the tread portion to form a tire skeleton. Configure. Further, the end portion of each carcass layer 13 on the inner side in the tire radial direction is wound back and locked to the outer side in the tire width direction so as to wrap the bead core 11 and the bead filler 12. Further, the left and right carcass layers 13 are arranged separately in the tire width direction in the tread portion center region (carcass division structure). The carcass plies 131 and 132 are formed by rolling a plurality of carcass cords made of steel or an organic fiber material (for example, nylon, polyester, rayon, etc.) with a coat rubber.

  In such a carcass division structure, a hollow portion (a region where the carcass layers 13 and 13 are not disposed) is formed in the tread center region. At this time, the tension of the tire in the hollow portion is carried by the belt layer 14, and the rigidity in the left and right sidewall portions is ensured by the left and right carcass layers 13, 13, respectively. As a result, the weight of the tire can be reduced while maintaining the internal pressure holding capability of the tire and the rigidity of the sidewall portion.

  The belt layer 14 is formed by laminating a pair of cross belts 141 and 142, a belt cover 143, and a pair of edge covers 144, and is arranged around the outer periphery of the carcass layer 13. The pair of cross belts 141 and 142 is formed by rolling a plurality of belt cords made of steel or organic fiber material with a coating rubber, and having a belt angle of 10 [deg] or more and 30 [deg] or less in absolute value. Have. Further, the pair of cross belts 141 and 142 have belt angles with different signs from each other (inclination angle of the fiber direction of the belt cord with respect to the tire circumferential direction), and are laminated so that the fiber directions of the belt cords cross each other. (Cross ply structure). The belt cover 143 is formed by rolling a plurality of belt cords made of steel or organic fiber material with a coat rubber, and has a belt angle of 10 [deg] or more and 45 [deg] or less in absolute value. Further, the belt cover 143 is disposed so as to be laminated on the outer side in the tire radial direction of the cross belts 141 and 142. The pair of edge covers 144 and 144 are disposed on the outer side in the tire radial direction of the belt cover 143 and on the left and right edge portions.

  The tread rubber 15 is disposed on the outer circumference in the tire radial direction of the carcass layers 13 and 13 and the belt layer 14 to constitute a tread portion of the tire. The pair of side wall rubbers 16 and 16 are respectively arranged on the outer side in the tire width direction of the carcass layer 13 to constitute left and right side wall portions. The pair of rim cushion rubbers 17 and 17 are arranged on the outer sides in the tire width direction of the left and right bead cores 11 and 11 and the bead fillers 12 and 12, respectively, and constitute left and right bead portions.

  In the configuration of FIG. 1, as described above, the pneumatic tire 1 includes the pair of bead cores 11, 11, the pair of bead fillers 12, 12, and the pair of sidewall rubbers 16, 16. However, the present invention is not limited to this, and the pneumatic tire 1 may include a plurality of pairs of bead cores 11 and 11, a plurality of pairs of bead fillers 12 and 12, or a plurality of pairs of sidewall rubbers 16 and 16 (not shown). . For example, the structure by which the bead filler 12 is arrange | positioned 2 each on the tire right and left is mentioned.

  In the configuration of FIG. 1, the left and right bead fillers 12 and 12 may be omitted (not shown). Therefore, the structure which does not have the bead filler 12 is assumed. In this embodiment, the configuration having both the bead core 11 and the bead filler 12 (see FIG. 1), and the configuration having only the bead core 11 by omitting the bead filler 12 (not shown) are collectively referred to as a bead member. .

[Inner liner]
The pneumatic tire 1 has an inner liner 18 (see FIG. 1). The inner liner 18 is disposed so as to cover the left and right carcass layers 13 and 13 and the belt layer 14 on the inner peripheral surface of the tire, thereby suppressing oxidation due to exposure of these and preventing leakage of air filled in the tire. To do.

  The inner liner 18 includes a pair of side inner liners 181 and 181 and a belt lower inner liner 182, which are bonded together while being wrapped together. The pair of side inner liners 181 and 181 are belt-shaped rubber sheets, and are arranged so as to wrap around the tire along the left and right carcass layers 13 and 13 and to wrap both ends in the circumferential direction. The under-belt inner liner 182 is a belt-like rubber sheet, and is arranged so as to go around the tire along the belt layer 14 and wrap both ends in the circumferential direction. Further, the left and right side inner liners 181 and 181 and the belt lower inner liner 182 are disposed so as to wrap edges in the width direction. Thereby, a toroidal rubber sheet is formed, and the inner peripheral surface of the carcass layer 13 and the inner peripheral surface of the belt layer 14 are covered without a gap.

  The inner liner 18 may have an adhesive tie rubber (not shown). For example, tie rubber is laminated and integrated on the pair of side inner liners 181 and 181 and the belt lower inner liner 182. The side inner liner 181 adheres to the carcass layer 13 via a tie rubber, and the lower belt inner liner 182 adheres to the belt layer 14 via a tie rubber. Thereby, the adhesion state of the inner liner 18 is ensured appropriately.

[Pneumatic tire manufacturing method]
FIG. 2 is a flowchart showing a method for manufacturing the pneumatic tire 1 shown in FIG. 3-8 is explanatory drawing which shows the manufacturing method of the pneumatic tire 1 described in FIG. FIG. 9 is an explanatory view showing the effect of the manufacturing method of the pneumatic tire 1 shown in FIG. In these drawings, FIG. 3 shows a molded single side member X, and FIG. 4 schematically shows a molding process of the side member X. FIG. 5 shows a process of forming the belt / tread assembly Y. FIG. 6 shows a shaping process, and FIGS. 7 and 8 show a molded green tire Z. FIG. 9A and 9B respectively show two types of pneumatic tires 1A and 1B having the same cross-sectional height SH and different tread widths TW1 and TW2.

  The pneumatic tire 1 is manufactured as follows (see FIG. 2).

  In step ST11, a pair of side members X, X is formed (side member forming step ST11). As shown in FIGS. 2 and 3, one side member X includes one bead core 11, one bead filler 12, one carcass layer 13 (two stacked carcass plies 131 and 132), One side wall rubber 16, one rim cushion rubber 17, and one side inner liner 181 constituting the inner liner 18 are configured. In this step ST11, as shown in FIG. 4, each member is set to the side member forming drum 21. At this time, the bead core 11 is held at a predetermined position on the side of the side member molding drum 21 by a holding device (not shown), and the carcass layer 13 and the side inner liner 181 are placed on the side member molding drum 21 by the member pressing device 22. Retained. Then, the turn-up bladder 23 is used to wind up the carcass layer 13, the sidewall rubber 16, and the rim cushion rubber 17 so as to wrap the bead core 11 and the bead filler 12. And these members are crimped | bonded by the turnup bladder 23, and a uniform cross section and the cyclic | annular side member X are shape | molded. Further, the pair of left and right side members X and X are formed by the same process.

  In addition, as the side member shaping | molding drum 21, the holding device (illustration omitted), and the member pressing device 22, the structure of the existing primary green tire shaping | molding drum (illustration omitted) can be diverted, for example.

  In step ST12, the belt-tread assembly Y is formed (belt-tread assembly forming step ST12). As shown in FIGS. 2 and 5, the belt-tread assembly Y includes a belt layer 14 (a pair of cross belts 141, 142, a belt cover 143 and a pair of edge covers 144, 144), a tread rubber 15, and an inner member. It is comprised from the belt lower inner liner 182 which comprises the liner 18. As shown in FIG.

  In this step ST12, as shown in FIG. 5, each member is wound around the outer periphery of the forming drum 24 and formed. These members are pressure-bonded to form a cylindrical belt-tread assembly Y. The forming drum 24 can be expanded and contracted in the axial direction and the radial direction according to the size of the belt / tread assembly Y. A known drum can be used as the molding drum 24.

  In step ST13, a shaping process is performed (shaping step ST13). In this step, as shown in FIGS. 2 and 6, the pair of side members X, X and the belt / tread assembly Y are pressure-bonded to form a green tire Z having a toroidal shape. Specifically, the pair of side members X, X are held on the left and right bead lock drums 25, 25, and the belt / tread assembly Y is held from the outer circumferential side by transfer (not shown). The pair of side members X and X are expanded by the vulcanization bladder 26 and pressed against the belt and tread assembly Y while the distance between the left and right bead lock drums 25 and 25 is narrowed. As a result, the pair of side members X and X and the belt / tread assembly Y are pressure-bonded to form the green tire Z.

  Here, in the green tire Z, as shown in FIG. 7 and FIG. 8, the side inner liners 181 and 181 of the left and right side members X and X and the belt lower inner liner 182 of the belt and tread assembly Y are tires. They are arranged so as to wrap in the width direction. At this time, the wrap width W1 is set in a range of 1 [mm] ≦ W1 ≦ 10 [mm]. As a result, the bonding margin between the left and right side inner liners 181 and 181 and the lower belt inner liner 182 is optimized, and the inner peripheral surface of the carcass layers 13 and 13 and the inner peripheral surface of the belt layer 14 are covered without any gaps. Is done. In addition, by setting the lower limit of the wrap width W1 to W1 = 1 [mm] and leaving a bonding allowance, the opening of the lap portion between the side inner liners 181 and 181 and the lower belt inner liner 182 at the time of tire vulcanization is properly performed. Is prevented.

  Moreover, in the green tire Z, as shown in FIG. 7, the carcass layers 13 and 13 and the belt layer 14 are disposed so as to be wrapped in the tire width direction. At this time, the wrap width W2 is set in a range of 5 [mm] ≦ W2, preferably in a range of 25 [mm] ≦ W2. Thereby, the internal pressure holding | maintenance capability of a tire and the rigidity of a sidewall part are maintained. The upper limit of the wrap width W2 is preferably in the range of W2 ≦ 0.1 × Wb [mm] with reference to the width Wb of the wide cross belt 141 in the tire width direction. As a result, the tire weight can be effectively reduced by the carcass division structure. The lap width W2 is the tire width of the innermost end of the carcass layer 13 (out of the two carcass plies 131 and 132) in the tire width direction and the widest cross belt 141 that forms the belt layer 14. It is measured as the distance in the tire width direction from the outer end in the direction.

  Further, in the green tire Z, as shown in FIG. 8, both end portions of the inner liner 18 are arranged so as to wrap in the tire circumferential direction. At this time, the wrap width W3 is set in a range of 0 [mm] ≦ W3 ≦ 10 [mm]. Thereby, the inner peripheral surface of the carcass layer 13 and the inner peripheral surface of the belt layer 14 are appropriately covered without a gap.

  In step ST14, a vulcanization molding process of the green tire Z is performed (tire vulcanization molding step ST14). In this step ST14, the green tire Z is filled in a tire vulcanization mold (not shown). Next, the tire vulcanization mold is heated, the green tire Z is expanded radially outward by a pressurizing device, and comes into contact with the tire molding die of the tire vulcanization mold. In addition, when the green tire Z is heated, the rubber molecules and sulfur molecules in the tread portion are bonded and vulcanized. At this time, the shape of the tire molding die is transferred to the tread surface of the green tire Z, and the tire tread pattern is molded. Then, the molded tire is pulled out from the tire vulcanization mold.

  In the method for manufacturing the pneumatic tire 1, for example, as shown in FIG. 9, two types of air having the same cross-sectional height SH, tread widths TW1 and TW2 and tire peripheral lengths TP1 and TP2 that are different from each other. When manufacturing the entering tires 1A and 1B, the manufacturing process of the tire can be facilitated.

  That is, in the pneumatic tire manufacturing method (see FIG. 27) in which the inner liner has a single structure, the green tire Z is molded in accordance with the tire peripheral lengths TP1 and TP2 (see FIG. 9) to be molded. It is necessary to change the axial length of the drum 100 (step change operation). For this reason, a work time required for the changeover operation is long, and a changeable forming drum is required.

  On the other hand, in the method for manufacturing the pneumatic tire 1, since the inner liner 18 has a divided structure composed of left and right side inner liners 181 and 181 (see FIG. 1), the left and right side members X and X are mutually connected. It can be molded independently (see FIG. 4). Therefore, the step of changing the axial length of the side member forming drum is not required, and the forming step of the side member X can be simplified.

  In the pneumatic tire 1 of FIG. 1, as shown in FIG. 10, the side inner liners 181 and 181 of the left and right side members X and X and the belt lower inner liner 182 of the belt / tread assembly Y are tires. They are arranged so as to wrap in the width direction. Further, the wrap width W1 is optimized within a predetermined range. Here, in the configuration of FIG. 10, the side inner liner 181 and the under-belt inner liner 182 have edges having a rectangular cross-sectional shape (bat shape), and the edges are arranged so as to be overlapped with each other.

  However, the present invention is not limited to this, and as shown in FIG. 11, the side inner liner 181 and the lower belt inner liner 182 have edges with cross-sectional shapes (butt splice shapes) cut out at angles, and the edges are joined. You may wrap and arrange | position so that it may match. At this time, as shown in FIG. 12, the edge portion of the side inner liner 181 and the edge portion of the belt inner liner 182 may be overlapped with each other while being displaced. Thus, the inner peripheral surface of the belt layer 14 is covered without a gap by arranging the side inner liner 181 and the belt lower inner liner 182 so as to wrap. Thereby, the oxidation of the belt layer 14 is suppressed and the air tightness of the tire is ensured. 11 and 12 is preferable in that the material cost of the tire can be reduced because the amount of the inner liner member used can be reduced as compared with the configuration of FIG. Furthermore, the configuration of FIG. 11 is preferable in that the unevenness of the tire inner peripheral surface can be reduced, and the appearance of the tire can be improved.

  In addition, the wrap width W1 is set by arranging the edge end surfaces of the left and right side inner liners 181 and 181 and the edge end surfaces of the belt lower inner liner 182 in contact with each other over the entire circumference of the tire. W1 = 0 [mm] can be set (not shown). However, in order to reliably prevent the butted portion from opening, it is preferable that the wrap width W1 is 1 [mm] ≦ W1.

  Further, the lap portions and the lap width W3 (see FIG. 8) at both ends of the inner liner 18 in the tire circumferential direction are also configured as shown in FIGS. 10 to 12 (the bat shape shown in FIG. 10 or the butt splice shape shown in FIGS. 1 and 12). The structure in which the end portions of each other are wrapped together can be similarly employed.

[Modification]
FIGS. 13-18 is explanatory drawing which shows the modification of the manufacturing method of the pneumatic tire 1 described in FIG. In these drawings, FIG. 13 shows a flowchart of a method for manufacturing the pneumatic tire 1. FIG. 14 shows a single side member X. 15 to 18 show the molding process of the side member X.

  2 and 3, the side member X is molded including the sidewall rubber 16 and the rim cushion rubber 17 in the side member molding step ST11.

  However, the present invention is not limited to this, and as shown in FIGS. 13 and 14, one side member X includes one bead core 11, one bead filler 12, and one carcass layer 13 (carcass plies 131 and 132). One side inner liner 181 may be included. At this time, similarly to the configuration of FIG. 4, each member can be pressure-bonded by the turn-up bladder 23 to form the side member X (see FIG. 15). In the shaping step ST23, the pair of side members X and X, the belt / tread assembly Y, the left and right side wall rubbers 16 and 16, and the left and right rim cushion rubbers 17 and 17 are pressure-bonded to form a green tire. Z (see FIG. 7) is formed. Even with this configuration, the green tire Z can be formed appropriately.

  In the configuration in which the side member X includes the chafer 19, as shown in FIG. 16, the side member X may be molded by pressing the chafer 19 and another member in the side member molding step ST21.

  In the pneumatic tire 1 shown in FIG. 1, the carcass layer 13 has a two-layer structure in which two carcass plies 131 and 132 are laminated. However, the present invention is not limited to this, and the carcass layer 13 has a single-layer structure or a three-layer structure. You may have the above multilayered structure (illustration omitted). In such a case, one side member X has a single carcass ply 131.

  As described above, the configuration of the side member X can be appropriately changed depending on the specification of the tire. Accordingly, one side member X may be configured to include at least one bead core 11, one bead filler 12, one carcass ply 131, and one side inner liner 181 (see FIG. 13 and FIG. 13). (See FIG. 14).

  In the configuration of FIG. 4, the side member X is formed by using the side member forming drum 21, the member pressing device 22, and the turn-up bladder 23. However, the present invention is not limited to this, and the side member X may be formed by using a wrapping bladder 27 as shown in FIG. The wrapping bladder 27 winds up the carcass layer 13 and the side inner liner 181 from the outside so that the carcass layer 13 and the side inner liner 181 wrap around the bead core 11 and the bead filler 12, and wraps each member from the surroundings and presses the members. It has a structure.

  In addition, as shown in FIG. 18, the carcass layer 13 and the side inner liner 181 may be wound around the bead core 11 and the bead filler 12 using a roller 28. Specifically, the roller 28 is composed of a pair of roll-shaped members whose opening angles are narrowed in the circumferential direction, and each member constituting the side member X is set on the roller 28 and rotated in the circumferential direction. The carcass layer 13 and the side inner liner 181 are wound around the bead core 11 and the bead filler 12. As such a roller 28, for example, an existing molding machine for winding a bead cover (not shown) around the bead portion may be employed.

  FIG. 19 is an explanatory view showing a modification of the method for manufacturing the pneumatic tire 1 shown in FIG. This figure shows the forming process of the belt-tread assembly Y.

  In the configuration of FIG. 6, the vulcanization bladder 26 has a pair of left and right bladders, and these bladders are arranged in parallel corresponding to the left and right side members X, X. Then, the vulcanization bladder 26 simultaneously expands each bladder, whereby the left and right side members X, X are pressed against the belt / tread assembly Y, respectively. In such a configuration, since the vulcanizing bladder 26 has a pair of bladders corresponding to the left and right side members X, X, the right and left side members X, X and the belt / tread assembly Y are properly crimped. preferable.

  However, the present invention is not limited to this, and the vulcanizing bladder 26 may be a single bladder, and the left and right side members X, X may be pressed against the belt-tread assembly Y by this single bladder (not shown). ).

  Further, as shown in FIG. 19, a shaping lever 29 may be used in place of the vulcanization bladder 26 to perform shaping. This shaping lever 29 has a plurality of levers arranged in the tire circumferential direction and over the entire circumference, and by raising these levers simultaneously, the left and right side members X, X are attached to the belt-tread assembly Y. Press and crimp each. Even with such a configuration, the green tire Z can be formed appropriately.

  20-25 is explanatory drawing which shows the modification of the pneumatic tire 1 described in FIG. In these drawings, FIG. 20 schematically shows an arrangement configuration of the carcass layer 13 and the inner liner 18 of the pneumatic tire 1 shown in FIG. 1, and FIGS. 21 to 25 show modified examples thereof.

  As shown in FIG. 20, the pneumatic tire 1 in FIG. 1 has a carcass division structure in which a pair of carcass layers 13 and 13 are arranged separately on the left and right sides of the tire. Thereby, weight reduction of the tire is achieved, ensuring tire rigidity. The inner liner 18 includes a pair of side inner liners 181 and 181 and a belt lower inner liner 182, and these end portions are bonded to each other while being overlapped with each other in the tire width direction (see FIG. 8). Thereby, the inner liner 18 covers the inner peripheral surface of the carcass layers 13 and 13 and the inner peripheral surface of the belt layer 14 without a gap.

  On the other hand, in the modification of FIG. 21, the pneumatic tire 1 has an intermediate carcass ply 133 in the configuration of FIG. The intermediate carcass ply 133 is disposed on the inner side in the tire radial direction of the belt layer 14, and is disposed so as to wrap on the left and right carcass layers 13, 13 at the left and right edges, respectively. Thereby, the intermediate carcass ply 133 fills the hollow portion between the left and right carcass layers 13 and 13, and the rigidity of the tire is reinforced. The intermediate carcass ply 133 is assembled to the belt / tread assembly Y, for example, in the belt / tread assembly molding step ST12 (ST22). In the shaping step ST13 (ST23), shaping is performed while the intermediate carcass ply 133 and the left and right carcass layers 13 and 13 are overlapped with each other.

  Further, in the modification of FIG. 22, in the configuration of FIG. 20, the inner liner 18 has a pair of side inner liners 181 and 181, and these side inner liners 181 and 181 extend to the center region of the tread portion. Wrapped to be placed. For this reason, the belt lower inner liner 182 (see FIG. 20) is omitted. Even in such a configuration, the inner peripheral surfaces of the carcass layers 13 and 13 and the inner peripheral surface of the belt layer 14 are covered without a gap.

  At this time, it is preferable that the wrap width W4 of the left and right side inner liners 181 and 181 is set in a range of 2 [mm] ≦ W4 ≦ 10 [mm]. Thereby, the inner peripheral surface of the carcass layer 13 and the inner peripheral surface of the belt layer 14 are appropriately covered without a gap. Moreover, opening of the lap | wrap part of the side inner liners 181 and 181 at the time of tire vulcanization is prevented by being 2 [mm] <= W4. Moreover, by being W4 <= 10 [mm], the unevenness | corrugation of a tire internal peripheral surface is suppressed and the external appearance property of a tire is ensured. The lap width W4 is measured for the green tire Z after shaping. Further, as the wrap structure of the left and right side inner liners 181 and 181, the configuration shown in FIGS. 10 to 12 (the structure in which the ends of the bat shape of FIG. 10 or the butt splice shape of FIGS. 1 and 12 are mutually wrapped) is used. It can be employed as well.

  Further, in the modification of FIG. 23, in the configuration of FIG. 20, the pair of carcass layers 13 and 13 extend to the center region of the tread portion and are arranged so as to wrap with each other. Thereby, the structural strength of the tire is reinforced.

  Further, in the modified example of FIG. 24, in the modified example of FIG. 23, the left and right side inner liners 181 and 181 further extend to the center region of the tread portion and are arranged so as to wrap each other. Thereby, the inner peripheral surfaces of the carcass layers 13 and 13 are covered without a gap.

  In the modification of FIG. 25, the belt lower inner liner 182 is omitted in the configuration of FIG. In such a configuration, since the belt layer 14 (see FIG. 1) is exposed inside the tire, there is a concern about leakage of internal pressure and oxidative deterioration due to the filled air, but the exposed portion is the thickest rubber in a general tire. Due to the crown portion, leakage of internal pressure can be minimized by the thickness of the rubber. Further, the oxidative deterioration can be suppressed by filling the tire with nitrogen gas.

[effect]
As described above, the method for manufacturing the pneumatic tire 1 includes a bead member (bead core 11, bead filler 12), carcass layer 13, sidewall rubber 16, rim cushion rubber 17, and part of the inner liner 18. Side member forming step ST11 (see FIGS. 3 and 4) for forming the side member X having the side inner liner 181 to be formed, and a belt tread for forming the belt tread assembly Y having the belt layer 14 and the tread rubber 15. An assembly forming step ST12 (see FIG. 5) and a shaping step ST13 (see FIG. 6) for joining and shaping the pair of side members X and X and the belt-tread assembly Y (see FIG. 2) are provided.

  Moreover, the manufacturing method of this pneumatic tire 1 shape | molds the side member X which has the side inner liner 181 which comprises a bead member (bead core 11, bead filler 12), the carcass layer 13, and a part of inner liner 18. As shown in FIG. Side member forming step ST21 (see FIGS. 14 and 15), belt-tread assembly forming step ST22 (see FIG. 5) for forming the belt-tread assembly Y having the belt layer 14 and the tread rubber 15, and a pair of A shaping step ST23 (see FIG. 6) for joining and shaping the side members X and X, the belt tread assembly Y, the pair of sidewall rubbers 16 and 16, and the pair of rim cushion rubbers 17 and 17 (see FIG. 13). reference).

  In these configurations, the pneumatic tire 1 includes the left and right carcass layers 13 and 13 having a divided structure, and the left and right side inner liners 181 and 181 having a divided structure (see FIG. 1). X and X can be formed independently in a state of being separated from each other (see, for example, FIGS. 3 and 4). Thereby, compared with the manufacturing method (refer FIG. 27) of the pneumatic tire which an inner liner has a single structure, there exists an advantage which can simplify the manufacturing process of a tire, and the advantage which can improve the quality of a tire. . Specifically, there are the following advantages.

  (1) For example, as shown in FIG. 9, it is assumed that two types of pneumatic tires 1A and 1B having the same cross-sectional height SH and different tread widths TW1 and TW2 are manufactured. At this time, in the method for manufacturing a pneumatic tire in which the inner liner has a single structure (see FIG. 27), a molding drum is formed in accordance with the tire peripheral lengths TP1 and TP2 (see FIG. 9) in the molding process of the side member X. It is necessary to change the axial length of 100 (see FIG. 27) (change operation). On the other hand, in the method for manufacturing the pneumatic tire 1, since the inner liner 18 has a divided structure composed of left and right side inner liners 181 and 181 (see FIG. 1), the left and right side members X and X are mutually connected. It can be molded independently (see, for example, FIG. 4). Therefore, the step of changing the axial length of the side member forming drum becomes unnecessary, and there is an advantage that the forming step of the side member X can be simplified.

  (2) Since the left and right side members X, X have an independent structure, two types of pneumatic tires 1A, 1B having the same cross-sectional height SH and mutually different tread widths TW1, TW2 (see FIG. 9) ), The side member X can be shared. This has the advantage that the inventory of semi-finished products can be reduced.

  (3) Since the left and right side members X, X can be formed independently of each other, the side member forming drum 21 (see FIG. 4) having a simple structure is used without using the existing changeable forming drum 100. Thus, the side member X can be formed. Further, for example, the side member X can be formed using a roll-up type bladder 27 (see FIG. 17) or a roller 28 (see FIG. 18). Thereby, the capital investment concerning shaping | molding of the side member X can be reduced significantly, and there exists an advantage which can improve productivity.

  (4) In general, the dimensional accuracy of the product tire depends on the accuracy of the peripheral length, and the accuracy of the peripheral length depends on the winding accuracy of the carcass layer. Here, in the manufacturing method of a pneumatic tire in which the inner liner has a single structure (see FIG. 27), when the internal pressure is filled in the green tire in the tire vulcanization molding process, the carcass layer is greatly increased through the inner liner. The peripheral length tends to change due to the tension. In this respect, in the method for manufacturing the pneumatic tire 1, the inner liner 18 has a divided structure including the left and right side inner liners 181, 181. Therefore, the tension acting on the carcass layer is reduced, and the peripheral length changes. Is suppressed. Thereby, there is an advantage that the dimensional accuracy of the product tire improves and the quality of the tire improves.

  Further, in the manufacturing method of the pneumatic tire 1, in the shaping step ST13 (ST23), the pair of side members X and X are expanded in diameter by the vulcanization bladder 26 and are crimped to the belt tread assembly Y (FIG. 6). reference).

  In the method for manufacturing the pneumatic tire 1, the pair of side members X and X are expanded in diameter by the shaping lever 29 and are crimped to the belt / tread assembly Y (see FIG. 19).

  In addition, the method for manufacturing the pneumatic tire 1 includes a step ST12 (ST22) in which a belt lower inner liner 182 constituting a part of the inner liner 18 is assembled to the belt tread assembly Y (FIGS. 1 and 20). In the shaping step ST13 (ST23), shaping is performed while the belt lower inner liner 182 and the left and right side inner liners 181 and 181 are overlapped with each other (see FIGS. 6 to 8). Thereby, the inner peripheral surface of the carcass layers 13 and 13 and the inner peripheral surface of the belt layer 14 are covered without a gap.

  In the method for manufacturing the pneumatic tire 1, shaping is performed in the shaping step ST13 (ST23) while the left and right side inner liners 181 and 181 are overlapped with each other (see FIGS. 22 and 24). Thereby, the inner peripheral surface of the carcass layers 13 and 13 and the inner peripheral surface of the belt layer 14 are covered without a gap.

  Further, in the method for manufacturing the pneumatic tire 1, the shaping is performed in the state where the left and right side inner liners 181 and 181 are separated from each other in the shaping step ST13 (ST23) (see FIG. 25).

  FIG. 26 is a chart showing results of performance tests of the pneumatic tire manufacturing method according to the embodiment of the present invention.

  In this performance test, (1) water pressure resistance and (2) internal pressure retention performance were evaluated for a plurality of pneumatic tires with different manufacturing methods (see FIG. 26).

  (1) Evaluation regarding pressure resistance performance was made by assembling a test tire with a rim, injecting water into the tire, measuring the pressure when the tire broke down, and indexing the conventional example as 100. The larger the index, the better the pressure resistance performance, which is preferable.

  (2) For the evaluation of the internal pressure retention performance, the tire is left for 3 months under an initial pressure of 200 [kPa], a room temperature of 21 [° C.] and no load. The measurement interval of the internal pressure is every 4 days, and the a value is obtained by regressing the following expression Pt / Po = exp (−at) as the measurement pressure Pt, the initial pressure Po, and the elapsed days t. Using the obtained a, t = 30 (days) is substituted, and β = [1-exp (−at)] × 100 is obtained. Let β be the rate of pressure drop per month (% / month). The reciprocal was expressed as an index with the conventional example being 100. The larger the index, the better the internal pressure holding performance, which is preferable.

  The pneumatic tires 1 of Examples 1 and 2 have the structure described in FIGS. 1 and 20, and the inner liner 18 includes a pair of side inner liners 181 and 181 and an under-belt inner liner 182. The pneumatic tires 1 of Examples 1 and 2 are both manufactured by the manufacturing method described in FIGS. Further, the pneumatic tires 1 of Examples 3 and 4 have the structure shown in FIG. 22, and the inner liner 18 is configured by wrapping or butting the left and right side inner liners 181 and 181 with each other. The pneumatic tire 1 of Examples 3 and 4 is based on the manufacturing method described in FIGS. 2 to 6, and the side inner liner extended to the center region of the tread portion in the side member forming step ST <b> 11 (see FIG. 4). 181 is used, and the belt lower inner liner 182 is omitted in the belt tread assembly molding step ST12 (see FIG. 5), and the left and right side inner liners 181 and 181 are overlapped with each other in the shaping step ST13. In this state (see FIG. 22), shaping is performed (not shown).

  Further, in Example 2, the side inner liners 181 and 181 of the left and right side members X and X and the belt lower inner liner 182 of the belt and tread assembly Y are brought into contact with each other with the end surfaces of the edge portions being brought into contact with each other. They are arranged in a state (not shown). For this reason, the lap width W1 is W1 = 0 [mm], but the butted portion is not opened all around the tire (W1 is not negative). Similarly, in the fourth embodiment, the left and right side inner liners 181 and 181 are arranged in a state where the end surfaces of the edge portions are brought into contact with each other (not shown). For this reason, the lap width W4 is W4 = 0 [mm], but the butted portion is not opened all around the tire (W4 is not negative).

  Moreover, the pneumatic tire 1 of Examples 1-4 has tire size 235 / 40R18. The inner liner 18 (side inner liners 181 and 181 and under-belt inner liner 182) is made of a butyl rubber composition having a thickness of 1.0 [mm].

  In the conventional pneumatic tire, the inner liner 18 has a structure in which the pair of side inner liners 181 and 181 and the under-belt inner liner 182 have a single structure (one rubber sheet) in the configuration of FIG. This conventional pneumatic tire is manufactured by the manufacturing method shown in FIG.

  As shown in the test results, in the pneumatic tires 1 of Examples 1 to 4, it can be seen that (1) water pressure resistance and (2) internal pressure retention performance are appropriately secured.

  1, 1A, 1B Pneumatic tire, 11 bead core, 12 bead filler, 13 carcass layer, 131, 132 carcass ply, 133 intermediate carcass ply, 14 belt layer, 141, 142 cross belt, 143 belt cover, 144 edge cover, 15 Tread rubber, 16 side wall rubber, 17 rim cushion rubber, 18 inner liner, 181 side inner liner, 182 under belt inner liner, 19 chafer, 21 side member forming drum, 22 member pressing device, 23 turnup bladder, 24 forming drum , 25 Beadlock drum, 26 Vulcanized bladder, 27 Encased bladder, 28 Roller, 29 Shaping lever, X side member, Y belt and tread assembly, Z green tire

Claims (7)

A pneumatic tire manufacturing method comprising a pair of bead members, a pair of carcass layers, a belt layer, a tread rubber, a pair of sidewall rubbers, a pair of rim cushion rubbers, and an inner liner,
A side member molding step of molding a side member having a side inner liner constituting a part of the bead member, the carcass layer, the sidewall rubber, the rim cushion rubber, and the inner liner;
A belt tread assembly molding step of molding a belt tread assembly having the belt layer and the tread rubber;
A pneumatic tire manufacturing method comprising: a shaping step of joining and shaping the pair of side members and the belt-tread assembly. A pneumatic tire manufacturing method comprising a pair of bead members, a pair of carcass layers, a belt layer, a tread rubber, a pair of sidewall rubbers, a pair of rim cushion rubbers, and an inner liner,
A side member molding step of molding a side member having a side inner liner constituting a part of the bead member, the carcass layer, and the inner liner;
A belt tread assembly molding step of molding a belt tread assembly having the belt layer and the tread rubber;
A pneumatic tire manufacturing method comprising: a pair of side members, the belt-tread assembly, a pair of the side wall rubbers, and a pair of the rim cushion rubbers for shaping.   3. The method for manufacturing a pneumatic tire according to claim 1, wherein in the shaping step, the pair of side members is expanded in diameter by a bladder and pressure-bonded to the belt-tread assembly.   3. The method for manufacturing a pneumatic tire according to claim 1, wherein, in the shaping step, the pair of side members is expanded in diameter by a shaping lever and pressure-bonded to the belt-tread assembly. A step of assembling a belt lower inner liner constituting a part of the inner liner to the belt tread assembly; and
The method for manufacturing a pneumatic tire according to any one of claims 1 to 4, wherein, in the shaping step, the shaping is performed while the belt inner liner and the left and right side inner liners are overlapped with each other.   The method for manufacturing a pneumatic tire according to any one of claims 1 to 4, wherein, in the shaping step, the shaping is performed while the left and right side inner liners are overlapped with each other.   The method for manufacturing a pneumatic tire according to any one of claims 1 to 4, wherein, in the shaping step, the shaping is performed in a state where the left and right side inner liners are separated from each other.