Pneumatic radial tires

• US 5,403,174 A
• Filed: 01/26/1993
• Issued: 04/04/1995
• Est. Priority Date: 03/05/1991
• Status: Expired due to Fees

• Current Assignee: Bridgestone Corporation
• Original Assignee: Bridgestone Corporation
• Inventors: Yamazaki, Tadashi, Ushikubo, Hisao
• Primary Examiner(s): Bushey, Charles S.
• Application Number:
  US08/009,975
• Time in Patent Office: 798 Days
• Field of Search: 264/315, 264/326, 425/28.1, 425/32, 425/35, 425/43, 425/48, 425/52
• US Class Current: 425/43
• CPC Class Codes: B29D 2030/0655 Constructional or chemical features of the flexible cores
• CPC Class Codes: B29D 30/0654 Flexible cores therefor, e.g. bladders, bags, membranes, diaphragms elastic cores or mandrels for shaping of plastics B29C33/505; bags for isostatic pressing in compression moulding B29C43/12, B29C43/3642
• CPC Class Codes: B29D 30/08 Building tyres

Abstract

A pneumatic tire having improved high-speed running performances is manufactured by conducting vulcanization of a green tire with a mold provided at a position corresponding to a given position between neighborhood of shoulder portion and neighborhood of bead portion with at least one protrusion which protrudes inside the mold and continuously extends in the circumferential direction of the mold and consists of a first arc segment having a center of curvature located outside from the inner surface of the mold and second arc segments each having a center of curvature located inside from the inner surface of the mold and smoothly connecting to the first arc segment at upper and lower ends in the radial direction of the mold.

Claims

1. A bladder and mold used for the vulcanization of a green tire comprising;

said mold provided at its inner surface portion corresponding to a given position between neighborhood of shoulder portion and neighborhood of bead portion in a tire to be manufactured at least one protrusion which protrudes inwardly and continuously extends in the circumferential direction of the mold;

said protrusion comprising a first arc segment having a center of curvature located outside from the inner surface of the mold and second arc segments each having a center of curvature located inside from the inner surface of the mold and smoothly connecting to the first arc segment at upper and lower ends in the radial direction of the mold, said bladder comprising means for generating a pushing force of the bladder at a position corresponding to the protrusion of the mold that is smaller than a pushing force of the remaining portion of said bladder except for a bladder bead portion.

2. The bladder and mold according to claim 1, wherein said means for generating a pushing force at the position corresponding to the protrusion of the mold that is reduced comprises a projection protruding inward from the bladder at such position.

3. The bladder and mold according to claim 1, wherein said means for generating a pushing force at the position corresponding to the protrusion of the mold that is reduced comprises a thickened portion consisting of a projection protruding inward and an outer recess substantially similar to the protrusion of the mold in the bladder at such position.

4. The bladder and mold according to claim 1, wherein said means for generating a pushing force at the position corresponding to the protrusion of the mold that is reduced comprises a reinforcing member embedded in the bladder at such position.