Method for manufacturing motorcycle tire

Patent metadata

Field	Value
Publication number	US-9962891-B2
Application number	US-201414270996-A
Country	US
Kind code	B2
Filing date	May 6, 2014
Priority date	May 20, 2013
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A method for manufacturing a motorcycle tire comprises: building a raw tire main body, building a breaker, sticking the breaker, and building a band. The building of the breaker comprises: moving two cylindrical support rings to operating positions, swelling the raw tire main body to have its crown portion protruding from the support rings through a gap therebetween, and winding a breaker ply material on the support rings to form a cylindrical breaker ply whose inner surface is adhered to the raw tire main body. The sticking of the breaker comprises: expanding a profiled deck to swell the raw tire main body into a second swollen state, and turning down both edge portions of the breaker while being supported by the profiled deck. The building of the band comprises: spirally winding a tape on the curved breaker ply while being supported by the profiled deck.

First claim

The invention claimed is:

1. A method for manufacturing a motorcycle tire which tire comprises a tread portion, a pair of sidewall portions, a pair of bead portions each with a bead core therein, a carcass extending between the bead portions through the tread portion and the sidewall portions, a breaker disposed radially outside the carcass in the tread portion and composed of two or three plies each composed of cords laid parallel with each other at an inclination angle of from 10 to 40 degrees with respect to the tire circumferential direction, and a band disposed radially outside the breaker in the tread portion and composed of at least one ply of at least one cord wound spirally and circumferentially of the tire, the method comprising:
a raw tire main body building process for building a cylindrical raw tire main body comprising a cylindrical carcass formed by winding a strip of carcass ply material into a cylindrical shape and disposing the bead cores in both end portions of the cylindrical carcass,
a breaker building process for building a cylindrical breaker by winding the plies composed of cords into a cylindrical shape,
wherein the breaker building process comprises:
a support ring closing step in which a pair of support rings each having a cylindrical outer surface are moved from their axially outer standby positions to their axially inner operating positions, wherein the support rings are disposed one on each side of an axial center corresponding to the tire equatorial plane, and supported movably in the axial direction so as to come close to each other or get away from each other,
a first swelling step in which the raw tire main body is swollen into a toroidal shape, while decreasing the distance between the bead cores, so as to achieve a first swollen state in which a crown portion of the swollen raw tire main body protrudes by 5 to 30 mm radially outwardly from the cylindrical outer surfaces of the support rings through a gap therebetween, and
a winding step in which the plies composed of cords of the breaker are wound on the support rings, so as to extend together across the gap, around an exterior of the support rings, whereby the cylindrical breaker, whose inner circumferential surface is adhered to the protruding crown portion of the raw tire main body, is formed;
a sticking process for applying both edge portions of the cylindrical breaker to the raw tire main body swollen into the toroidal shape by turning down the edge portions,
wherein the sticking process comprises:
a second swelling step in which, after the support rings are moved to the standby positions, a profiled deck is expanded from a contracted state where it does not contact the raw tire main body to an expanded state, while decreasing the distance between the bead cores, so that the raw tire main body with the cylindrical breaker thereon is swollen to a second swollen state, and the inside thereof is supported by the profiled deck, and
a turn-down step in which, in the state of the raw tire main body supported by the profiled deck, both edge portions of the cylindrical breaker are turned down onto the raw tire main body in the second swollen state so as to shape the cylindrical breaker into a curved breaker curved along the outer circumferential surface of the profiled deck,
wherein in the turn-down step, the turning down of both edge portions of the cylindrical breaker is by the use of a pair of pressure rollers, each of which is moved, relatively to a radially outermost one of the plies composed of cords around the radially outermost ply in one respective circumferential direction, while contacting and pressing a respective one of the edge portions toward the raw tire main body, and
each one respective circumferential direction is associated with the inclination with respect to the tire circumferential direction of the cords of the radially outermost ply contacting with and pressed by the pair of the pressure rollers such that the respective circumferential direction of each of the rollers exerts a pulling action on the cords of the radially outermost ply,
wherein the pulling action of each pressure roller is achieved by pressing directly on the radially outermost ply at a first one of the edges of the cylindrical breaker with a first one of the pressure rollers while the raw tire main body is rotating in a first direction and the second one of the pressure rollers remains out of contact with the radially outermost ply, and thereafter pressing directly on the radially outermost ply at the second one of the edges of the cylindrical breaker with the second one of the pressure rollers while the raw tire main body is rotating in a second direction which is opposite of the first direction and the first pressure roller remains out of contact with the radially outermost ply; and
a band building process for building the band by winding a tape for forming the band,
wherein the band building process comprises:
a tape winding step in which the tape is spirally wound on the outer circumferential surface of the curved breaker in the state supported by the profiled deck so that the band is formed along the outer circumferential surface of the profiled deck.

2. The method for manufacturing a motorcycle tire according to claim 1 , wherein
a stretch of the band during vulcanizing the raw tire is in a range of from 0.5% to 5.0%.

3. The method for manufacturing a motorcycle tire according to claim 1 , wherein
said gap between the cylindrical outer surfaces of the support rings is in a range of 50 to 100 mm in the axial direction.

Assignees

• Sumitomo Rubber Ind

Inventors

• Otani Masafumi

Classifications

• B29D30/242

  for manufacturing substantially cylindrical tyre components without cores or beads, e.g. treads or belts · CPC title

• B29D30/70

  Annular breakers · CPC title

• B29D30/1628

  by feeding a continuous band and winding it helically, i.e. the band is fed while being advanced along the core axis, to form an annular element (winding and joining, helically in general B29C53/58) · CPC title

• B29D30/36

  Expansion of tyres in a flat form {, i.e. expansion to a toroidal shape independently of their building-up process}, e.g. of tyres built by the flat-tyres method or by jointly covering two bead-rings · CPC title

• B29D2030/2664

  the drum comprising at least two portions that are axially separable, e.g. the portions being supported by different shafts, e.g. in order to facilitate the insertion of the beads · CPC title