# US 9,039,400 B2 · Rigid core for forming tire

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- Number: US 9,039,400 B2
- Document ID: US9039400B2
- Status: Granted
- Kind: B2
- Application number: 14/379,153
- Filed: 2013-02-27
- Published: 2015-02-05
- Granted: 2015-05-26
- Earliest claimed: 2012-03-19
- Assignees: Sumitomo Rubber Industries, Ltd.
- Applicants: Sumitomo Rubber Industries, Ltd.
- Inventors: Kei Kohara
- Web page: https://patentgrep.com/patent/US9039400B2

## CPC

- B29D 30/0661: {Rigid cores therefor, e.g. annular or substantially toroidal cores (cores for building tyres B29D30/12; drums for building tyres B29D30/24)}
- B29C 33/38: characterised by the material or the manufacturing process (B29C33/44 takes precedence)
- B29D 30/0606: {Vulcanising moulds not integral with vulcanising presses (for solid tyres B29D30/02)}
- B29D 30/12: Cores
- B29C 33/02: with incorporated heating or cooling means
- B29K 2995/0012: having particular thermal properties
- B29L 2030/00: Pneumatic or solid tyres or parts thereof {(conveyor belts B29L2031/7092; drive belts B29L2031/7094; fourdrinier belts B29L2031/733)}
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES

## Abstract

A rigid core for forming a tire is configured so that the non-uniformity of the amount of thermal expansion of the core body is reduced to improve the quality of the tire. The core body comprises divided core pieces (10i , 10o) divided inward and outward in a tire radial direction at a tire radial position (P) including a maximum width position (P0) of the tire forming surface. Outward divided core pieces (10o) disposed outward in the tire radial direction than the maximum width position (P0) and inward divided core pieces (10i) disposed inward in the tire radial direction than the maximum width position (P0) are respectively formed of metal materials different from each other in coefficient of thermal expansion. The coefficient of thermal expansion of the inward divided core piece (10i) is higher than a coefficient of thermal expansion of the outward divided core piece (10o).

## Claims

### Claim 1

A rigid core for forming a tire comprising:
a core body provided on an outer surface thereof with a tire forming surface configured to form thereon a green tire by sequentially sticking tire structural members, the rigid core being configured to be loaded together with the green tire formed on the tire forming surface into a vulcanization mold so as to subject the green tire to vulcanization molding between the vulcanization mold and the core body,
wherein the core body comprises a plurality of divided core pieces configured to be divided inward and outward in a tire radial direction at a tire radial position P including a maximum width position P0 at which the tire forming surface bulges most outward in a tire axial direction,
wherein an outward divided core piece disposed more outward in the tire radial direction than the maximum width position P0, and an inward divided core piece disposed more inward in the tire radial direction than the maximum width position P0 are respectively formed of metal materials different from each other in coefficient of thermal expansion, and
wherein a coefficient of thermal expansion of the inward divided core piece is higher than a coefficient of thermal expansion of the outward divided core piece.

### Claim 2 (depends on 1)

The rigid core for forming a tire according to claim 1, wherein the core body comprises three or more divided core pieces respectively formed of metal materials different from one another in coefficient of thermal expansion, and the divided core pieces have a higher coefficient of thermal expansion as being disposed more inward in the tire radial direction.