MOLD PIN, TIRE MOLD AND TIRE MANUFACTURING METHOD

• US 20140103577A1
• Filed: 08/14/2013
• Published: 04/17/2014
• Est. Priority Date: 10/11/2012
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: ABE, Shotaro
• Granted Patent: US 9,724,885 B2
• Time in Patent Office: Days
• US Class Current: 264/326
• CPC Class Codes: B29D 2030/0612 Means for forming recesses or protrusions in the tyres, e.g. grooves or ribs, to create the tread or sidewalls patterns
• CPC Class Codes: B29D 30/0606 Vulcanising moulds not integral with vulcanising presses for solid tyres B29D30/02
• CPC Class Codes: B29D 30/0662 Accessories, details or auxiliary operations
• CPC Class Codes: B29D 30/66 Moulding treads on to tyre casings, e.g. non-skid treads with spikes

Abstract

A mold pin fixed to a tread mold for a tire tread and forming a stud hole is disclosed. The mold pin is provided at one end of its main shaft portion with an expanded portion having a larger outer diameter. The expanded portion comprises a supporting part formed integrally with the main shaft portion, and an outer-shell part disposed on the outer surface of the supporting part to define the maximum outer diameter of the expanded portion. when a force directed from the main shaft portion toward the expanded portion is applied to the outer-shell part, the outer-shell part is moved so as to reduce the maximum outer diameter.

Claims

1. A mold pin used by being fixed to a tread mold for molding a tread of a vehicle tire to form a stud hole in the tread, comprising

a main shaft portion to be fixed at its one end to the tread mold so as to protrude from a tread molding surface of the tread mold, and

an expanded portion disposed at the other end of the main shaft portion and having an outer diameter more than the outer diameter of the main shaft portion, wherein

the expanded portion comprises a supporting part formed integrally with the main shaft portion, and

a outer-shell part disposed on the outer surface of the supporting part to define the maximum outer diameter of the expanded portion, and

the outer-shell part is movably supported by the supporting part such that when a force directed from said one end toward said other end of the main shaft portion is applied to the outer-shell part, the outer-shell part is moved so as to reduce the maximum outer diameter.

2. The mold pin according to claim 1, wherein

the supporting part is bulb-shaped,

the outer-shell part closely contacts with the outer surface of the supporting part, and

the volumetric thermal expansion coefficient P1 of the supporting part is the same as or more than the volumetric thermal expansion coefficient P2 of the outer-shell part.

3. The mold pin according to claim 2, wherein

the ratio P1/P2 is not less than 1.000 and not more than 1.015.

4. The mold pin according claim 1 wherein

the ratio D2/D1 of the maximum outer diameter D2 of the expanded portion to the outer diameter D1 of the main shaft portion is not less than 1.2 and not more than 3.0.

5. The mold pin according to claim 1 wherein

the outer-shell part is made up of a plurality of sector shells, and

a radially inside end of each sector shell is connected to the supporting part by the use of a connector made of a heat-resistant, flexible and deformable resin in a cantilever manner.

6. The mold pin according to claim 5, wherein

the maximum outer diameter of the supporting part is more than the outer diameter of the main shaft portion, and

when the sector shell is subjected to a force directed from said one end toward said the other end, a radially outside end of the sector shell is movable about the connector as a point of support to a position inside a cylinder circumscribed with the maximum outer diameter position of the supporting part.

7. A tire mold comprising a tread mold provided with a plurality of the mold pins as set forth in claim 1.

8. A method for manufacturing a vehicle tire comprising a step of vulcanizing a tread portion of the tire by the use of a tread mold provided with a plurality of the mold pins as set forth in claim 1.

9. The mold pin according claim 2, wherein

the ratio D2/D1 of the maximum outer diameter D2 of the expanded portion to the outer diameter D1 of the main shaft portion is not less than 1.2 and not more than 3.0.

10. The mold pin according claim 3, wherein

the ratio D2/D1 of the maximum outer diameter D2 of the expanded portion to the outer diameter D1 of the main shaft portion is not less than 1.2 and not more than 3.0.

11. The mold pin according to claim 2, wherein

the outer-shell part is made up of a plurality of sector shells, and

a radially inside end of each sector shell is connected to the supporting part by the use of a connector made of a heat-resistant, flexible and deformable resin in a cantilever manner.

12. The mold pin according to claim 3, wherein

the outer-shell part is made up of a plurality of sector shells, and

a radially inside end of each sector shell is connected to the supporting part by the use of a connector made of a heat-resistant, flexible and deformable resin in a cantilever manner.

13. The mold pin according to claim 4 wherein

the outer-shell part is made up of a plurality of sector shells, and

a radially inside end of each sector shell is connected to the supporting part by the use of a connector made of a heat-resistant, flexible and deformable resin in a cantilever manner.

14. A tire mold comprising a tread mold provided with a plurality of the mold pins as set forth in claim 2.

15. A tire mold comprising a tread mold provided with a plurality of the mold pins as set forth in claim 3.

16. A tire mold comprising a tread mold provided with a plurality of the mold pins as set forth in claim 4.

17. A tire mold comprising a tread mold provided with a plurality of the mold pins as set forth in claim 5.

18. A tire mold comprising a tread mold provided with a plurality of the mold pins as set forth in claim 6.

19. A method for manufacturing a vehicle tire comprising a step of vulcanizing a tread portion of the tire by the use of a tread mold provided with a plurality of the mold pins as set forth in claim 2.

20. A method for manufacturing a vehicle tire comprising a step of vulcanizing a tread portion of the tire by the use of a tread mold provided with a plurality of the mold pins as set forth in claim 3.