JP4496461B2 - Pneumatic tire and manufacturing method thereof - Google Patents

Description

  The present invention relates to a pneumatic tire used as a radial tire for passenger cars, for example, and a method for manufacturing the same.

  Generally, this type of pneumatic tire includes a tread portion that contacts a road surface, a sidewall portion that forms a side surface of the tire, a shoulder portion that is formed between the tread portion and the sidewall portion, a sidewall portion, and a tire. An inner liner that keeps airtightness in the tire between a pair of annular bead members, a carcass member that reinforces the tire in the radial direction, and a tire A belt that reinforces the belt in the circumferential direction is disposed so as to overlap each other, and a tread member and a side wall member are attached to a toroidal shape in which a carcass member is straddled across each bead member.

Further, the carcass member is formed of a sheet-like rubber member having a large number of carcass cords arranged in the circumferential direction of the tire, and is formed in a cylindrical shape by sticking the both ends in the longitudinal direction, and the both ends in the width direction are formed. Each carcass cord is locked to each bead member by folding back to the side of the sidewall from the inside to the outside of the tire so as to wind the bead member (see, for example, Patent Document 1).
JP 11-48724 A

  However, in the pneumatic tire, since the carcass member is folded back to the side wall side, the end portion side of the folded carcass cord is present in the side portion of the tire in the radial direction of the tire. Since the number of carcass cords is different between the portion where the end portion is present and the portion where the end portion is not present, the rigidity varies greatly. For this reason, the tension applied to the sidewall portion due to the internal pressure of the tire becomes nonuniform in the radial direction of the tire, and there is a problem that the bending performance of the sidewall portion is deteriorated.

  In addition, in order to fold the carcass member to the side of the sidewall, a complicated and expensive molding apparatus equipped with a folding bladder or the like is required, and there is a problem that the cost required for the manufacturing equipment is high.

  Furthermore, when trying to reduce the pitch of the carcass cord in the tread portion in order to improve the performance of the tire, since each carcass cord is arranged radially from the bead portion toward the tread portion, the carcass cord in the bead portion is the tire. The pitch of the carcass cords in the tread portion cannot be made sufficiently small.

  The present invention has been made in view of the above-described problems, and the object thereof is to make the tension applied to the sidewall portion uniform, and without requiring a complicated and expensive molding apparatus. Another object of the present invention is to provide a pneumatic tire capable of sufficiently reducing the pitch of the carcass cord in the tread portion and a manufacturing method thereof.

In order to achieve the above object, the present invention provides a pneumatic tire in which a plurality of carcass cords extending from a tread portion to a bead portion through a sidewall portion are arranged in the tire circumferential direction, and an end portion side of the carcass cord is disposed on the pneumatic tire. A predetermined number of tires are alternately arranged on the inner and outer sides of the bead member in the circumferential direction, and at least one of the ends of the carcass cords arranged on the inner and outer sides of the bead member is on the inner peripheral surface side of the bead member. wraps around so formed are arranged the ends of the carcass cords are disposed inside and outside of the bead member to abut one another.

Further, the present invention provides a pneumatic tire manufacturing method in which a plurality of carcass cords extending from a tread portion through a sidewall portion to a bead portion are arranged in the tire circumferential direction, and the end side of some of the carcass cords is arranged. After a predetermined number of tires are arranged on the bead side every predetermined number in the circumferential direction, the bead members are arranged in the bead portion so that the end portions of these carcass cords are inside the bead members, and the ends of other carcass cords The part side is arranged outside the bead member, and at least one of the ends of the carcass cords arranged inside and outside the bead member is bent so as to wrap around the inner peripheral surface side of the bead member, and the inside and outside of the bead member characterized in that it comprises a step that mutually abutting end portions of the carcass cord is arranged.

  Thus, in the present invention, the end portions of the carcass cord are alternately arranged on the inner side and the outer side of the bead member by a predetermined number, so that the end portion side of the carcass cord is folded back to a part of the side wall portion in the radial direction. In this case, the number of carcass cords in the radial direction of the sidewall portion can be made uniform. In this case, since at least one of the end portions of the carcass cords arranged on the inner side and the outer side of the bead member is formed so as to wrap around the inner peripheral surface side of the bead member, the carcass cord is sufficiently attached to the bead member. Can be locked. Further, since the end portions of the carcass cords are alternately arranged inside and outside the bead member by a predetermined number, the density in the circumferential direction of the carcass cord on the bead side may be reduced with respect to the total number of carcass cords. it can.

  According to the present invention, since the number of carcass cords in the radial direction of the sidewall portion can be made uniform, the rigidity of the sidewall portion does not vary greatly, and the tension applied to the sidewall portion is thereby reduced. It can be made uniform, and the bending performance of the sidewall portion can be improved. In this case, since the carcass cord can be sufficiently locked to the bead member, there is an advantage that the strength against the internal pressure of the tire is not lowered. Moreover, since it is not necessary to use a complicated and expensive molding apparatus for folding the carcass member to the side wall as in the prior art, the cost required for the manufacturing equipment can be greatly reduced. Further, since the density in the circumferential direction of the carcass cord on the bead side can be reduced with respect to the total number of carcass cords, the number of carcass cords is increased by that amount and the pitch of the carcass cord in the tread portion is reduced. Can do. As a result, the carcass cords can be arranged at high density in the tread portion, and the performance such as durability can be remarkably improved.

  1 to 7 show a first embodiment of the present invention. FIG. 1 is a radial cross-sectional view of a pneumatic tire, FIG. 2 is an enlarged cross-sectional view of its main part, and FIGS. 3 to 6 are manufacturing processes thereof. FIG. 7 is a side view showing a carcass cord and a bead member.

  The pneumatic tire includes a tread portion 1 that is in contact with a road surface, a sidewall portion 2 that forms a side surface of the tire, a shoulder portion 3 that is formed between the tread portion 1 and the sidewall portion 2, and a sidewall portion 2. And a bead portion 4 located between a tire wheel (not shown).

  That is, the pneumatic tire includes an inner liner 11 that maintains airtightness in the tire, a carcass member 12 that reinforces the tire in the radial direction, and a tire in the circumferential direction between a pair of bead members 10 formed in an annular shape. A total of two belts 13 to be reinforced are placed on top of each other, and the tread member 14 and the side wall member 15 are pasted on a toroidal shape so that the carcass member 12 straddles each bead member 10. Is formed.

  The bead member 10 includes a bead core 10a in which wires such as piano wires are bundled and a bead filler 10b made of rubber having a substantially triangular cross section. The bead filler 10b is fixed to the outer periphery of the bead core 10a in advance.

  The inner liner 11 is made of sheet-like rubber and is disposed on the inner peripheral surface side of the carcass member 12.

  The carcass member 12 has a large number of carcass cords 12a arranged in the circumferential direction of the tire, and both end sides of each carcass cord 12a are respectively engaged with the bead cores 10a. The carcass cord 12a is formed of polyester, steel, or the like, and extends from the tread portion 1 through the sidewall portion 2 to the bead portion 4. In this case, the end side of each carcass cord 12a is alternately arranged inside and outside the bead member 10 one by one in the circumferential direction of the tire, and the end portion 12b of the carcass cord 12a arranged inside the bead member 10 And, at least one of the end portions 12c of the carcass cord 12a disposed on the outside is bent so as to go around to the inner peripheral surface side of the bead member 10. For example, as shown in FIG. 2 (a), only the end portion 12 b of the carcass cord 12 a arranged inside the bead member 10 may be bent so as to wrap around the inner peripheral surface side of the bead member 10. Further, as shown in FIG. 2 (b), only the end portion 12 c of the carcass cord 12 a arranged on the outer side of the bead member 10 may be bent so as to wrap around the inner peripheral surface side of the bead member 10. Further, as shown in FIG. 2 (c), both end portions 12b and 12c of the carcass cord 12a disposed inside and outside the bead member 10 are bent so as to wrap around the inner peripheral surface side of the bead member 10, You may make it extend the edge parts 12b and 12c to the approximate center of the thickness direction of the bead member 10, respectively.

  Each belt 13 is formed by covering a number of reinforcing wires extending in the circumferential direction of the tire with a sheet-like rubber material, and is disposed on the outer peripheral surface side of the carcass member 12 so as to overlap each other. In this case, the reinforcing wire of the belt 13 is made of steel, high-strength fiber, or the like.

  The tread member 14 is made of a rubber material that covers the outer periphery of each belt 13, and a groove 14a that forms a predetermined tread pattern is provided on the outer peripheral surface thereof.

  The sidewall member 15 is made of a rubber material that covers the outer surface of the carcass member 12, and is formed to have flexibility in the radial direction of the tire.

  Next, a method for manufacturing the pneumatic tire will be described. In addition, the process demonstrated below shows the assembly | attachment process of the carcass member 12 and the bead member 10, and it abbreviate | omits about another manufacturing process, since it is equivalent to the past.

  First, as shown in FIG. 3, each carcass cord 12a of the carcass member 12 is arranged on the tread side, and as shown in FIG. 4, every other carcass cord 12a is folded back to the side wall side. Next, as shown in FIG. 5, after placing the bead member 10 on the carcass cord 12a folded back to the side wall side, the other remaining carcass cord 12a is folded back on the bead member 10, and as shown in FIG. The carcass member 12 and the bead member 10 are bent by bending at least one of the end portions 12b and 12c of the carcass cord 12a disposed inside and outside the bead member 10 to the lower end side of the bead member 10, respectively. Assembly is complete.

  As described above, according to the present embodiment, the end portions 12b and 12c of the carcass cord 12a are alternately arranged on the inner side and the outer side of the bead member 10 one by one. The number of carcass cords 12a in the radial direction of the sidewall portion 2 can be made uniform without the 12c side being folded back to a part of the sidewall portion 2 in the radial direction. Thereby, since the rigidity of the side wall part 2 does not partially differ greatly, the tension applied to the side wall part 2 can be made uniform, and the bending performance of the side wall part 2 can be improved.

  Further, since at least one of the end portions 12b and 12c of the carcass cord 12a disposed on the inner side and the outer side of the bead member 10 is bent so as to wrap around the inner peripheral surface side of the bead member 10, the carcass cord 12a is The bead member 10 can be sufficiently locked as in the conventional case, and there is an advantage that the strength against the internal pressure of the tire is not lowered. In this case, since the carcass cord 12a can be locked to the bead member 10 by slightly bending the carcass cord 12a, it is necessary to use a complicated and expensive molding apparatus for folding the carcass member to the side wall as in the prior art. Therefore, the cost required for manufacturing equipment can be greatly reduced.

  Furthermore, by arranging the end portions 12b and 12c of the carcass cord 12a one by one alternately on the inside and outside of the bead member 10, the circumferential density of the carcass cord 12a on the bead side is halved as shown in FIG. Therefore, the number of carcass cords 12a can be increased correspondingly, and the pitch P of the carcass cords 12a in the tread portion 1 can be reduced. Thereby, the carcass cords 12a can be arranged at high density in the tread portion 1, and the performance such as durability can be remarkably improved.

In the above-described embodiment, the end portions 12b and 12c of the carcass cord 12a are alternately disposed on the inner side and the outer side of the bead member 10, respectively. However, two or more end portions 12b and 12c may be disposed. Alternatively, different numbers may be arranged on the inside and outside of the bead member 10. In the first embodiment, the carcass cords 12 a are arranged individually on the inside and outside of the bead member 10, respectively. In the second embodiment, as shown in FIG. 8, a plurality of strip portions 12d each having a predetermined number of carcass cords (not shown) are formed on both ends in the width direction of the carcass member 12, as shown in FIG. As shown in FIG. 9, after the end portions of some of the belt-like portions 12d of the carcass member 12 are arranged on the bead side every other circumferential direction of the tire, the belt-like portions 12d are The bead member 10 may be disposed so as to be inside the bead member 10, and the other band-shaped portion 12 d may be disposed outside the bead member 10.

  Further, as a third embodiment, a plurality of strip-like carcass members 16 each having a predetermined number of carcass cords (not shown) as shown in FIG. 11 are arranged in the circumferential direction of the tire, and some carcass as shown in FIG. After arranging the end portions of the members 16 on the bead side every other circumferential direction of the tire, the bead members 10 are arranged so that the end portions of these carcass members 16 are inside the bead members 10. The end side of the other carcass member 16 may be disposed outside the bead member 10.

  That is, in the second and third embodiments, since the carcass cord can be disposed on the inner side and the outer side of the bead member 10 together with the plurality of belt-like portions 12d or the plurality of carcass members 16 of the carcass member 12, for example, molding is performed. This is advantageous when it is wound around a drum and molded.

FIG. 1 is a radial sectional view of a pneumatic tire showing a first embodiment of the present invention. Principal enlarged sectional view of pneumatic tire Schematic perspective view showing manufacturing process of pneumatic tire Schematic perspective view showing manufacturing process of pneumatic tire Schematic perspective view showing manufacturing process of pneumatic tire Schematic perspective view showing manufacturing process of pneumatic tire Side view showing carcass cord and bead member The schematic perspective view which shows the manufacturing process of the pneumatic tire which shows the 2nd Embodiment of this invention. The schematic perspective view which shows the manufacturing process of the pneumatic tire which shows the 2nd Embodiment of this invention. The schematic perspective view which shows the manufacturing process of the pneumatic tire which shows the 3rd Embodiment of this invention. The schematic perspective view which shows the manufacturing process of the pneumatic tire which shows the 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Tread part, 2 ... Side wall part, 4 ... Bead part, 10 ... Bead member, 12 ... Carcass member, 12a ... Carcass cord, 12b, 12c ... End part, 12d ... Band-shaped part, 16 ... Carcass member

Claims (7)

In a pneumatic tire formed by arranging a plurality of carcass cords extending from the tread portion to the bead portion through the sidewall portion in the tire circumferential direction,
While arranging the end portion side of the carcass cord alternately inside and outside the bead member by a predetermined number in the circumferential direction of the tire,
Forming at least one of the ends of the carcass cords arranged on the inside and outside of the bead member so as to wrap around the inner peripheral surface side of the bead member ,
A pneumatic tire characterized in that the ends of the carcass cords arranged inside and outside the bead member are arranged to abut each other . Only the end portion of the carcass cord disposed inside the bead member is formed so as to go around to the inner peripheral surface side of the bead member.
The pneumatic tire according to claim 1. Only the end portion of the carcass cord arranged outside the bead member is formed so as to go around to the inner peripheral surface side of the bead member.
The pneumatic tire according to claim 1. Both the end portions of the carcass cords arranged on the inner side and the outer side of the bead member are formed so as to wrap around the inner peripheral surface side of the bead member.
The pneumatic tire according to claim 1. In the manufacturing method of the pneumatic tire formed by arranging a plurality of carcass cords extending from the tread portion to the bead portion through the sidewall portion in the tire circumferential direction,
After arranging the end side of some carcass cords on the bead side by a predetermined number every predetermined number in the circumferential direction of the tire,
While arranging the bead member in the bead part so that the end part side of these carcass cords is inside the bead member, the end part side of the other carcass cord is arranged outside the bead member,
Bending at least one of the ends of the carcass cords arranged on the inner side and the outer side of the bead member so as to wrap around the inner peripheral surface side of the bead member ,
The pneumatic tire manufacturing method which comprises a step that mutually abutting end portions of the carcass cord arranged inside and outside of the bead member. Forming a plurality of belt-like portions each having a predetermined number of the carcass cords on both ends in the width direction of the carcass member;
After arranging the end side of the belt-shaped part of the carcass member on the bead side by a predetermined number every predetermined number in the circumferential direction of the tire,
The pneumatic tire manufacturing method according to claim 5 , wherein the bead member is arranged in the bead portion so that the belt-like portions are inside the bead member, and the other belt-like portion is arranged outside the bead member. Method. A plurality of strip-like carcass members each having a predetermined number of the carcass cords are arranged in the circumferential direction of the tire,
After arranging the end side of some carcass members on the bead side by a predetermined number every predetermined number in the circumferential direction of the tire,
Claim the end side of the carcass member while placing the bead member in the bead portion so that the inside of the bead member, characterized by disposing the end portion of the other of the carcass member on the outside of the bead member 5 The manufacturing method of the pneumatic tire of description.

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