Vulcanizing method of pneumatic bias tire

• US 6,514,447 B1
• Filed: 07/06/2000
• Issued: 02/04/2003
• Est. Priority Date: 07/06/1999
• Status: Expired due to Fees

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Sekoguchi, Masaharu, Mori, Shinichi
• Primary Examiner(s): Vargot, Mathieu D.
• Application Number:
  US09/610,902
• Time in Patent Office: 943 Days
• Field of Search: 264/315, 264/326, 425/35, 425/39
• US Class Current: 264/315
• CPC Class Codes: B29C 33/10 with incorporated venting means
• CPC Class Codes: B29C 33/405 Elastomers, e.g. rubber B29C33/50 takes precedence
• CPC Class Codes: B29C 33/76 Cores B29C33/02 - B29C33/70, B29C41/40, B29C53/74, B29C53/82 take precedence
• CPC Class Codes: B29C 37/006 Degassing moulding material or draining off gas during moulding venting means in moulds B29C33/10
• CPC Class Codes: B29D 2030/0655 Constructional or chemical features of the flexible cores
• CPC Class Codes: B29D 30/26 Accessories or details, e.g. membranes, transfer rings

Abstract

Disclosed is a vulcanizing method of a pneumatic bias tire having an aspect ratio Y of 25% or more and 55% or less from an unvulcanized tire, which comprises the step of expanding a rubber-made bladder from an inside of the unvulcanized tire in metallic molds, in which a bladder stretch ratio X of an outer diameter of the bladder when it is not expanded relative to a tire inner surface diameter, when the unvulcanized tire is pressed to the inner surfaces of the metallic molds by means of expansion of the bladder, is set in a range expressed by the following expression:

X=β−Y/α,

where 0.37<α<0.42, 310<β<320.

Claims

1. A vulcanizing method of a pneumatic bias tire having an aspect ratio Y of 25% or more and 55% or less from an unvulcanized tire, the aspect ratio Y being a tire sectional height H divided by a tire sectional width W times 100%, the vulcanizing method comprising the step of:

expanding a rubber-made bladder from an inside of the unvulcanized tire in metallic molds,

wherein a bladder stretch ratio X of a tire inner surface diameter when the unvulcanized tire is pressed to the inner surfaces of the metallic molds by means of expansion of the bladder relative to an outer diameter of the bladder when it is not expanded is set in a range expressed by the following expression;

2. The vulcanizing method of a pneumatic bias tire according to claim 1, wherein vent grooves are arranged on an area of a surface of the bladder, the area contacting at least a tire side portion, and a pattern of the vent grooves is made to be a polygonal mesh shape.

3. The vulcanizing method of a pneumatic bias tire according to claim 2, wherein a groove width of each vent groove is set in a range from 2 to 5 mm, and a depth thereof is set in a range from 0.2 to 0.7 mm.

4. The vulcanizing method of a pneumatic bias tire according to claim 1, wherein the pneumatic bias tire is a tire for competition, the tire having a rim diameter of 4 to 6 inches.