JP2011136669A - Pneumatic tire and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the uniformity of a tire by improving a method of winding band-shaped plies. <P>SOLUTION: A band layer 8 includes a jointless ply 12 formed by winding a long band-shaped ply 11 formed by covering a plurality of band cords 9 arranged parallel to each other by a topping rubber 10 spirally at an angle of 5° or smaller relative to a tire circumferential direction. The jointless ply 12 includes a first ply 12A formed by winding the first band-shaped ply 11A from a first start end S1 on a tire equator to one end G1 of a belt layer 7 in the tire axis direction and a second ply 12B formed by winding the second band-shaped ply 11B on the tire axial inner side from the second start end S2 of the belt layer 7 on the other end G side in the tire axis direction onto the tire equator C in the same direction as the first band-shaped path 11A. The winding terminal end E2 of the second band-shaped ply is made to butt to the first start end S1 of the first band-shaped ply 11A or wound on with a small length. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pneumatic tire in which variation in tire uniformity, particularly radial runout, is suppressed by improving a method for winding a belt-shaped ply constituting a band layer, and a method for manufacturing the same.

  FIG. 8 shows a developed plan view of the internal structure of the tread portion of a conventional pneumatic radial tire. The radial tire includes a carcass a, a belt layer b including two belt plies b1 and b2 disposed on the outer side thereof, and a band layer d disposed on the outer side of the belt layer b. Such a band layer d suppresses lifting or the like of the belt layer b and improves high-speed durability and steering stability.

  Further, as the band layer d, a pair of jointless plies j1, j2 formed by spirally winding a long belt-like ply p from the tire equator C to one direction side and the other side in the tire axial direction. Has been proposed.

  However, the conventional jointless plies j1 and j2 have their start ends m1 and m2 provided on the tire equator C and at substantially the same position in the tire circumferential direction, and each of the tires toward one side and the other side in the tire axial direction. Since it is wound helically at a small angle with respect to the circumferential direction, a substantially triangular gap e is formed in which the belt-like ply p is not formed outside the belt layer b near the tire equator, which is the winding start end. Will be. In such a gap e, there is a problem that the thickness of the tire is reduced, and variation in uniformity, particularly radial runout (hereinafter simply referred to as “RRO”), which is a variation in the tire outer dimension, is large. Related technologies include the following.

Japanese Patent Laid-Open No. 08-142226

  The present invention has been devised in view of the above problems, and the first starting end of the belt-like ply forming the jointless ply is arranged on the tire equator, and the second starting end is arranged in the tire axial direction. Based on the fact that it is arranged on the other end side and the second winding end is abutted against the first starting end or is wound with a small length, almost the entire belt layer, particularly on the tire equator, is joined with a jointless ply. The main object is to provide a pneumatic tire and a method for manufacturing the same in which the uniformity of the tire is improved by covering.

  The invention according to claim 1 of the present invention is a carcass that extends from the tread portion through the sidewall portion to the bead core of the bead portion, and is arranged on the outer side in the tire radial direction of the carcass and inside the tread portion and on the tire equator. A pneumatic tire comprising a belt layer made of a belt ply having a cord inclined at an angle of 15 to 35 ° with respect to the belt layer and a band layer disposed on the outer side in the tire radial direction of the belt layer, The layer consists of a jointless ply formed by spirally winding a long band ply in which a plurality of band cords arranged in parallel are covered with a topping rubber at an angle of 5 ° or less with respect to the tire circumferential direction. The jointless ply includes a first belt-like plastic from a first start end on the tire equator to one end side in the tire axial direction of the belt layer. A first ply in which a is wound, and a second belt-like ply in the same direction as the first belt-like ply on the inner side in the tire axial direction from the second starting end on the other end side in the tire axial direction of the belt layer to the tire equator And a winding end of the second belt-like ply is abutted against a first start end of the first belt-like ply or wound with a small length. And

  The invention according to claim 2 is the pneumatic tire according to claim 1, wherein the second start end is substantially at the same position as the first start end in the tire circumferential direction.

  The invention according to claim 3 is the pneumatic tire according to claim 1 or 2, wherein a winding end of the first belt-like ply is on the one end of the belt layer.

  According to a fourth aspect of the present invention, the first ply is inclined with respect to the tire circumferential direction from the first start end, and an inclined winding portion around which the first belt-like ply is wound, and is connected to the inclined winding portion. In addition, the first belt-like ply includes a parallel winding portion wound substantially in parallel with the tire circumferential direction, and the parallel winding portion is formed only at an end portion including the winding end and the parallel winding portion. The pneumatic tire according to claim 3, wherein a central angle of the wound portion is 250 to 290 °.

  The invention according to claim 5 is the pneumatic tire according to any one of claims 1 to 4, wherein the second starting end of the second ply is on the other end of the belt layer.

  According to a sixth aspect of the present invention, the second ply includes a parallel winding portion in which the second belt-like ply is wound substantially parallel to the tire circumferential direction from the second starting end, and the parallel winding portion. And an inclined winding portion in which the second belt-like ply is wound around the tire circumferential direction, and the parallel winding portion is formed only at an end portion including the second starting end, and The pneumatic tire according to claim 5, wherein a central angle of the parallel winding portion is 250 to 290 °.

  According to a seventh aspect of the present invention, the first ply includes a first inner layer portion in which the first belt-like ply is continuously wound from the first starting end to the one end of the belt layer, A first outer layer portion that is continuous with the first inner layer portion and is arranged on the outer side in the tire radial direction of the first inner layer portion by being spirally wound toward the tire equator side. In addition, the second ply is a second belt in which the second belt-like ply is wound outward in the tire axial direction from a second start end located on the tire equator side to the other end of the belt layer. An inner layer portion and the second inner layer portion are arranged on the outer side in the tire radial direction of the second inner layer portion by spirally winding the second belt-shaped ply toward the tire equator side to the winding end. The second outer layer A pneumatic tire non claim 1.

  The invention according to claim 8 is the method of manufacturing a pneumatic tire according to any one of claims 1 to 7, wherein the first applicator is provided on the surface of the wound body having a substantially cylindrical shape. A first fastening end of the first belt-like ply to be guided; a surface of the wound body; and a position spaced axially from the starting end of the first belt-like ply. A second starting end of the second belt-shaped ply guided by the second applicator, and rotating the wound body, and the first and second applicators are connected to the second belt-shaped ply. Are simultaneously moved in the same axial direction toward the first starting end of the first belt-like ply, whereby the first and second belt-like plies are spirally wound around the surface of the body to be wound. Forming the second ply, and winding end of the second belt-like ply, Characterized in that it comprises a fastening step of providing a winding overlap position or the small length matched to the winding starting end of one of the belt-like ply.

  In the pneumatic tire of the present invention, an elongated belt-like ply in which a band layer is coated with a plurality of band cords arranged in parallel with a topping rubber is formed on the outside of the belt layer at an angle of 5 ° or less with respect to the tire circumferential direction. It includes a jointless ply formed by winding in a spiral shape. The jointless ply includes a first ply in which a first belt-shaped ply is wound from one first start end on the tire equator to one end side in the tire axial direction of the belt layer, and the tire layer in the tire axial direction of the belt layer. A second ply in which a second belt-like ply is wound inward in the tire axial direction from the second start end on the other end side to the tire equator, and the winding end of the second belt-like ply is the first ply The first ply end of the belt-like ply is abutted or wound with a small length. As described above, the pneumatic tire of the present invention can cover almost the entire surface of the belt layer, particularly the vicinity of the tire equator with the jointless ply, so that the uniformity of the tire is improved, and in particular, the RRO variation is significantly improved. .

It is sectional drawing which shows the pneumatic tire of one Embodiment of this invention. It is a perspective view which shows one Embodiment of a strip | belt-shaped ply. It is an expansion | deployment top view of the band layer of this embodiment. It is an expansion | deployment top view of the band layer of other embodiment. It is AA sectional drawing of FIG. (A) thru | or (c) is the schematic which shows the manufacturing method of the jointless ply of this embodiment. It is an expansion | deployment top view which shows the internal structure of the tread part of a comparative example. It is an expansion | deployment top view explaining the internal structure of the conventional tread part.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the pneumatic tire 1 of the present embodiment includes a carcass 6 that extends from a tread portion 2 through a sidewall portion 3 to a bead core 5 of the bead portion 4, and the carcass 6 on the outer side in the tire radial direction. The belt layer 7 disposed inside the tread portion 2 and the band layer 8 disposed on the outer side in the tire radial direction of the belt layer 7 are shown in the present embodiment for passenger cars.

  The carcass 6 includes a main body portion 6a straddling a pair of bead cores 5 and 5 in a toroidal manner, and a folded portion 6b which is continuous from both sides of the main body portion 6a and is folded from the inner side to the outer side in the tire axial direction around the bead core 5. And at least one carcass ply 6A (in the present embodiment). In the carcass ply 6A, carcass cords made of, for example, organic fibers are arranged at an angle of, for example, 80 to 90 ° with respect to the tire equator C direction.

  In the present embodiment, the belt layer 7 is composed of two inner and outer belt plies 7A and 7B, and the inner belt ply 7A is formed wider than the outer belt ply 7B. Each of the belt plies 7A and 7B has a highly elastic belt cord such as a steel cord inclined at an angle of 15 to 35 ° with respect to the tire equator C. The belt plies 7A and 7B are overlapped so that the belt cords intersect each other. As a result, the belt layer 7 tightens the carcass 6 over substantially the entire width of the tread portion 2 to increase the rigidity of the tread portion 2.

  The band layer 8 is formed by winding a long belt-like ply 11 (shown in FIG. 2) spirally at an angle α of 5 ° or less with respect to the outer side of the belt layer 7 and the tire circumferential direction. In the embodiment, the jointless ply 12 is composed of one layer.

  As shown in FIG. 2, the belt-like ply 11 is a long ribbon-like long body having a substantially rectangular cross section in which a plurality of band cords 9 arranged in parallel at substantially equal intervals are covered with a topping rubber 10. is there. The band cord 9 is not particularly limited, but an organic fiber cord such as nylon, rayon, aromatic polyamide, or PEN is preferably used. Further, a steel cord may be adopted as necessary.

  Further, the width W1 of the belt-like ply 11 is desirably 5 to 20 mm, for example. When the width W1 is less than 5 mm, when the jointless ply 12 is formed, the number of windings of the belt-like ply 11 is increased and the productivity tends to deteriorate. Conversely, when it exceeds 20 mm, the winding workability tends to deteriorate. There is. The number of band cords 9 included in one belt-like ply 11 is preferably 2 or more and 10 or less, and the arrangement density is desirably 8 to 12 / cm.

  FIG. 3 shows a developed plan view of the band layer 8 of the present embodiment. The vertical axis in FIG. 3 indicates the angle in the tire circumferential direction, and the horizontal axis indicates the tire axial direction (the width direction of the belt layer 7). The jointless ply 12 includes a first ply 12A that substantially forms the right side of the tire equator C and a second ply 12B that substantially forms the left side of the tire equator C in the drawing.

  In the first ply 12A, the first belt-like ply 11A is continuously wound from the first starting end S1 on the tire equator C toward one end G1 in the tire axial direction of the belt layer 7 outward in the tire axial direction. It is formed by. Further, the second ply 12B has a second belt-like ply 11B different from the first belt-like ply 11A, and the tire equator C from the second start end S2 on the other end G2 side of the belt layer 7 in the tire axial direction. It is formed by continuously winding in the tire axial direction up to the top and in the same direction as the first belt-like ply 11A. The “first starting edge S1 on the tire equator C” means that the first starting edge S1 intersects the tire equator C. However, in consideration of manufacturing variations and the like, from the tire equator C, There may be a deviation within 3% of the width in the tire axial direction of the inner belt ply 7A.

  Further, the winding end E2 of the second belt-like ply 11B of the present embodiment is abutted against the first start end S1 of the first belt-like ply 11A or wound with a small length L. In such a jointless ply 12, the conventional gap e (shown in FIG. 8) is not formed in the vicinity of the tire equator C, and the belt-like ply substantially extends from one end G 1 to the other end G 2 of the belt layer 7. Since it can be made continuous, in the vicinity of the tire equator C, the thickness of the tread is made uniform in the circumferential direction. Thereby, in the pneumatic tire 1 of the present embodiment, tire uniformity, in particular, RRO variation on the tire equator C is significantly improved.

  In addition, the winding end E1 of the first belt-like ply 11A of the present embodiment is formed on one end G1 of the belt layer 7 in the tire axial direction, and the second start end S2 is formed on the belt layer 7. It is formed on the other end G2 in the tire axial direction. As a result, the jointless ply 12 is formed over the entire width of the belt layer 7 in the tire axial direction and the entire length in the tire circumferential direction, so that the tire uniformity is further improved. When the winding end E2 of the second belt-shaped ply and the first start end S1 are wound, if the length L is too large, there is a risk of adversely affecting variations in RRO. From such a viewpoint, the “small length” L is preferably 30 mm or less, more preferably 20 mm or less.

  Further, the first ply 12A includes a first inclined winding portion K1 that is inclined at, for example, 3 to 5 ° with respect to the tire circumferential direction from the first starting end S1, and the first belt-like ply 11A is wound around the first ply 12A. Formed from a first parallel winding portion H1 which is continuous with the first inclined winding portion K1 and the first belt-like ply 11A is wound substantially parallel to the tire circumferential direction (2 ° or less with respect to the tire circumferential direction). Is done. On the other hand, the second ply 12B is a second parallel winding portion in which the second belt-like ply 11B is wound substantially parallel to the tire circumferential direction (2 ° or less with respect to the tire circumferential direction) from the second starting end S2. H2 and a second inclined winding portion K2 that is connected to the second parallel winding portion H2 and is inclined at, for example, 3 to 5 ° with respect to the tire circumferential direction and wound with the second belt-like ply 11B. Is done.

  Further, the first parallel winding portion H1 is formed only at an end portion including the winding end E1. Further, the second parallel winding portion H2 is formed only at an end portion including the second starting end S2. Thus, the first parallel winding portion H1 of the present embodiment is formed to partially overlap the first inclined winding portion K1 on the one end G1. Further, the second parallel winding portion H2 is formed to partially overlap the second inclined winding portion K2 on the other end G2. Thereby, the belt-like plies 11 at both end portions in the tire axial direction restrain the belt layer 7 more firmly.

  In addition, the circumferential lengths of the first and second parallel winding portions H1 and H2 are not particularly limited. However, if the length is too large, the thickness of the tread at both end portions of the belt layer 7 increases. , RRO tends to deteriorate, and conversely, if it is too small, the restraining force on the belt layer 7 decreases, and RRO tends to deteriorate similarly. From this point of view, the central angle θ1 of the first parallel winding portion H1 around the tire rotation axis and the central angle θ2 of the second parallel winding portion H2 are preferably 250 ° or more, more preferably 260 ° or more. Is desirable, and preferably 290 ° or less, more preferably 280 ° or less.

  In the jointless ply 12 of the present embodiment, the first start end S1 and the second start end S2 are substantially at the same position in the tire circumferential direction. For this reason, since winding of the 1st strip | belt-shaped ply 11A and the 2nd strip | belt-shaped ply 11B can be started simultaneously, production efficiency improves. In particular, if the winding end E1 of the first strip ply 11A is substantially the same position in the tire circumferential direction as the winding end E2 of the second strip ply 11B, the first strip ply 11A and the second strip ply 11A Since the belt-like ply 11B can be wound simultaneously from the start of winding to the completion of winding, the production efficiency is further improved. It should be noted that substantially the same position in the tire circumferential direction may include a positional deviation within 5 ° in the central angle of the tire in consideration of variations in tire manufacturing.

  In addition, in order to form the jointless ply 12, the belt-like ply 11 can be wound by various methods. For example, in the embodiment of FIG. 3, the inclined winding portion K is wound so that the side edge F (shown in FIG. 2) of the belt-like ply 11 adjacent in the tire axial direction substantially contacts. Such a band layer 8 forms a cord layer having a substantially uniform thickness over almost the entire width of the belt layer 7, and thus helps to reduce variations in tire uniformity, particularly RRO. Further, as other winding methods of the belt-like ply 11, the side edges F and F may be separated from each other, or the side edges F are overlapped with each other in order to exert a large restraining force on the belt layer 7. It may be wound.

  FIG. 4 is a developed plan view of another embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line AA of FIG. In this embodiment, the first ply 12A includes a first inner layer portion 12A1 in which the first belt-like ply 11A is continuously wound from the first starting end S1 to one end G1 in the tire axial direction of the belt layer 7; The first inner layer portion 12A1 is connected to the first inner layer portion 12A1, and the first belt-like ply 11A is spirally wound toward the tire equator C side so that the first inner layer portion 12A1 is disposed on the outer side in the tire radial direction. And an outer layer portion 12A2.

  Further, the second ply 12B has a second belt-like ply 11B on the outer side in the tire axial direction from the second start end S2 positioned on the tire equator C side to the other end G2 of the belt layer 7 in the tire axial direction. The second inner layer portion 12B1 wound around the second inner layer portion 12B1, and the second belt-like ply 11B connected to the second inner layer portion 12B1 are spirally wound toward the winding ending point E2 toward the tire equator C side. And the second outer layer portion 12B2 disposed on the outer side in the tire radial direction of the two inner layer portions 12B1. Therefore, also in the present embodiment, the belt-like layer 11 is wound on both ends in the tire axial direction, so that the binding force to the belt layer 7 is exhibited.

  Further, as shown in FIG. 4, the widths W1 and W2 in the tire axial direction of the first outer layer portion 12A2 and the second inner layer portion 12B1 are not particularly limited, but the widths W1 and W2 are large. If the amount is too large, the weight and cost may be deteriorated. On the other hand, if the amount is too small, the improvement in restraining force of the belt layer 7 tends not to be sufficiently exhibited. From such a viewpoint, the widths W1 and W2 are preferably 32.5% or more, more preferably 35% or more, and preferably 42.5% of the width W in the tire axial direction of the inner belt ply 7A. Below, 40% or less is more desirable. Further, in order to further improve the uniformity of the tire, the ratio W1 / W2 between the widths W1 and W2 is preferably substantially equal to 1.0 ± 0.05.

  FIG. 6A conceptually shows a method for manufacturing the jointless ply 12 of the pneumatic tire 1 of the present embodiment.

  The manufacturing apparatus T used in this manufacturing method includes a base 13, a substantially cylindrical drum 14 rotatably supported on the base 13, and an applicator that can supply the belt-like ply 11 to the drum 14. 15.

  The base 13 includes a power transmission device (not shown) for rotating the drum 14 by a rotating shaft 16.

  The applicator 15 is formed, for example, in a conveyor shape, and continuously feeds the belt-like ply 11 to the belt ply 7B outside the drum 14 on its conveying surface. Although not shown, a rubber extruder or the like for continuously extruding the belt-like ply 11 is provided on the upstream side of the applicator 15. The applicator 15 is provided so as to be capable of reciprocating in at least the axial direction of the drum 14 by being supported by, for example, a three-dimensional movement device (not shown).

  The applicator 15 of the present embodiment is arranged with a first applicator 15A for supplying the first belt-like ply 11A, a position shifted from the first applicator 15A in the tire axial direction, and the second applicator 15A. And a second applicator 15B for supplying the belt-like ply 11B. Thereby, even if the 1st and 2nd applicators 15A and 15B are the same positions in the circumferential direction of the drum 14, they can move mutually without interfering with each other.

The manufacturing method of this embodiment is as follows.
First, as shown in FIG. 6A, the belt layer 7 is wound around the outer surface of the drum 14. Accordingly, in the present embodiment, the belt layer 7 and the drum 14 constitute a wound body M for winding the belt-like ply 11. Next, the first starting end S1 of the first belt-like ply 11A guided by the first applicator 15A is fixed on the tire equator C of the wound body M. Similarly, the second starting end S2 of the second strip ply 11B guided by the second applicator 15B is on the wound body M and in the axial direction from the first starting end S1 of the first strip ply 11A. It is fixed at a distance. In the present embodiment, the belt layer 7 is fixed on the other end G2 in the tire axial direction. A pressing roller (not shown) may be used in order to securely fix the first starting end S1 and the second starting end S2.

  Next, as shown in FIG. 6 (b), the wound body M is rotated (in the arrow direction A), and the first and second applicators 15A and 15B are replaced with the second belt-like ply 11B. The first belt-like ply 11A moves simultaneously in the same axial direction B in the direction approaching the first starting end S1. As a result, the first belt-like ply 11A is spirally wound around the outer surface of the wound body M on the one end G1 side, and the first ply 12A starts to be formed. Further, the second belt-like ply 11B is spirally wound around the outer surface of the wound body M on the other end G2 side, and the second ply 12B starts to be molded simultaneously with the first ply 12A. In this way, the winding time can be shortened by including the step of simultaneously winding the two first and second applicators 15A, 15B with the half width of the belt moved in the axial direction, Productivity is improved. In addition, the helical pitch of each belt-like ply 11 can be freely adjusted by individually adjusting the moving speeds of the applicators 15A and 15B in the axial direction. Needless to say, the second belt-like ply 11B may be wound in parallel with the tire circumferential direction within a range of a central angle of about 250 to 290 ° from the second starting end S2 around the tire rotation axis. .

  Next, as shown in FIG. 6 (c), the winding end E2 of the second belt-shaped ply is in contact with the winding start end S1 of the first belt-shaped ply 11A or wound at a small length. Cut and fastened. Further, the winding end E1 of the first strip ply is cut and fastened at the same position in the tire circumferential direction as the winding end E2 of the second strip ply. Thereby, the molding of the first and second plies 12A, 12B is completed at the same time. Needless to say, the first belt-like ply 11A may be wound around the first winding end E1 in the range of 250 to 290 ° in parallel with the tire circumferential direction.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the illustrated embodiments, and can be implemented in various forms.

In order to confirm the effect of the present invention, a pneumatic radial tire of size 235 / 50R18 was prototyped based on the specifications in Table 1. Each tire has the common internal structure shown in FIG. 1 except for the band layer. In addition, the inclination winding part in an Example is wound so that the side edge of the strip | belt-shaped ply adjacent in a winding direction may contact | connect substantially. FIG. 7A shows a band layer formed by winding one belt-like ply from one end to the other end in the tire axial direction around a cylindrical body using one applicator as Comparative Example 2. . Further, FIG. 7B shows, as Comparative Example 3, two applicators are used, and the start ends of the two belt-like plies are provided on the tire equator and are shifted by 150 ° to 210 ° in the tire circumferential direction. A band layer formed by spiral winding outward in the axial direction is shown. For this reason, the belt-like ply of Comparative Example 3 was attached with the other starting end by rotating the drum about half a circle after the one starting end was attached. The winding end was similarly fixed.
In each example, the drum rotation speed was the same.
The main common specifications are as follows.
<Carcass>
Number of carcass plies: 1 Carcass cord material: Polyester Carcass cord angle: 88 degrees <Belt layer>
Number of plies: 2 Belt cord: Steel Belt cord angle: +22 degrees / -22 degrees <band layer>
Number of plies: 1 Band cord material: Hybrid cord of nylon fiber and PEN fiber Band cord angle α: 0.31 degrees Band ply width: 11 cm
Number of cords of belt-like ply: 11 The test method is as follows.

<FV test of tire>
About the test tire, the variation of RRO was measured on the following conditions using the force variation testing machine based on the uniformity test conditions of JASO C607: 2000 (average value of 20 test pieces each). The RRO variation was calculated by measuring RRO at 1024 points on the tire circumference and obtaining the standard deviation of the measured values. The evaluation was performed using an index with the standard deviation of Comparative Example 1 as 100. The smaller the value, the better.
Tire size: 195 / 65R15
Rims: 6J x 15
Internal pressure: 2kPa
Load: 4.51kN
Speed: 60rpm

<Tire productivity>
The time required to wrap the belt-like ply around the outside of the belt layer of the cylindrical body was measured by the method of the comparative example and the example (average value of 20 test pieces). Evaluation was made with an index with Comparative Example 1 as 100. The smaller the value, the better.
The test results are shown in Table 1.

  As a result of the test, it can be confirmed that the uniformity of the example is significantly improved as compared with the comparative example.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Side wall part 4 Bead part 5 Bead core 6 Carcass 7 Belt layer 8 Band layer 9 Band cord 10 Topping rubber 11 Band-like ply 12 Jointless ply 12A First ply 12B Second ply C Tire equator E1 First Winding end of the first belt-like ply E2 Winding end of the second belt-like ply G1 One end in the tire axial direction G2 The other end in the tire axial direction S1 First start end S2 Second start end

Claims (8)

A carcass from the tread part through the sidewall part to the bead core of the bead part,
A belt layer made of a belt ply having a cord disposed on the outer side in the tire radial direction of the carcass and inside the tread portion and having a cord inclined at an angle of 15 to 35 ° with respect to the tire equator;
A pneumatic tire comprising a band layer disposed on the outer side in the tire radial direction of the belt layer,
The band layer is a jointless formed by winding a long band-shaped ply in which a plurality of band cords arranged in parallel with a topping rubber are spirally wound at an angle of 5 ° or less with respect to the tire circumferential direction. Including ply,
The jointless ply includes a first ply in which a first belt-like ply is wound from a first starting end on the tire equator to one end side in the tire axial direction of the belt layer;
A second ply in which a second belt-like ply is wound in the same direction as the first belt-like ply from the second start end on the other end side in the tire axial direction of the belt layer to the tire equator on the inner side in the tire axial direction. ,
A pneumatic tire characterized in that a winding end of the second belt-shaped ply is abutted against a first start end of the first belt-shaped ply or wound with a small length.   The pneumatic tire according to claim 1, wherein the second starting end is substantially at the same position in the tire circumferential direction as the first starting end.   The pneumatic tire according to claim 1 or 2, wherein a winding end of the first belt-like ply is on the one end of the belt layer. The first ply is inclined with respect to the tire circumferential direction from the first starting end, and the inclined winding portion around which the first belt-like ply is wound,
Continuing to the inclined winding portion, the first belt-like ply consists of a parallel winding portion wound substantially in parallel with the tire circumferential direction,
The pneumatic tire according to claim 3, wherein the parallel winding portion is formed only at an end portion including the winding end, and a central angle of the parallel winding portion is 250 to 290 °.   The pneumatic tire according to any one of claims 1 to 4, wherein a second start end of the second ply is on the other end of the belt layer. The second ply has a parallel winding portion in which the second belt-like ply is wound substantially parallel to the tire circumferential direction from the second starting end,
Consisting of this parallel winding portion and an inclined winding portion inclined with respect to the tire circumferential direction and wound with the second belt-like ply,
The pneumatic tire according to claim 5, wherein the parallel winding portion is formed only at an end portion including the second starting end, and a central angle of the parallel winding portion is 250 to 290 °. The first ply includes a first inner layer portion in which the first belt-shaped ply is continuously wound from the first start end to the one end of the belt layer, and the first ply is connected to the first inner layer portion and the first ply The first belt-shaped ply is spirally wound toward the tire equator side and includes a first outer layer portion disposed on the outer side in the tire radial direction of the first inner layer portion, and
The second ply includes a second inner layer portion in which the second belt-shaped ply is wound outward in the tire axial direction from a second starting end positioned on the tire equator side to the other end of the belt layer. And the second belt-like ply connected to the second inner layer portion is spirally wound toward the end of the winding toward the tire equator side, thereby being arranged on the outer side in the tire radial direction of the second inner layer portion. The pneumatic tire according to claim 1, comprising two outer layer portions. A method for manufacturing a pneumatic tire according to any one of claims 1 to 7,
Fixing the first starting end of the first belt-shaped ply guided by the first applicator to the surface of the wound body having a substantially cylindrical shape;
The second start end of the second strip ply guided by the second applicator is stopped on the surface of the wound body and at a position spaced apart from the start end of the first strip ply in the axial direction. Wearing process;
By rotating the wound body and simultaneously moving the first and second applicators in the same axial direction in which the second belt-like ply approaches the first start end of the first belt-like ply. A step of forming the first and second plies by spirally winding the first and second belt-like plies around the surface of the wound body;
A pneumatic tire comprising: a fastening step in which a winding end of the second belt-shaped ply is abutted with a winding start end of the first belt-shaped ply or is provided at a position where it is wound with a small length. Manufacturing method.

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