Pneumatic tire, method for manufacturing the same and method for manufacturing body ply

• US 20020195186A1
• Filed: 05/09/2002
• Published: 12/26/2002
• Est. Priority Date: 05/11/2001
• Status: Active Grant

• Current Assignee: Fuji Seiki Company Limited
• Original Assignee: Fuji Seiki Company Limited
• Inventors: Takagi, Shigemasa
• Granted Patent: US 6,969,440 B2
• Time in Patent Office: Days
• US Class Current: 152/542
• CPC Class Codes: B29D 2030/3264 using radially expandable, contractible mechanical means, e.g. circumferentially spaced arms, spring rollers, cages
• CPC Class Codes: B29D 30/32 Fitting the bead-rings or bead-cores; Folding the textile layers around the rings or cores
• CPC Class Codes: B29D 30/42 Endless textile bands without bead-rings
• CPC Class Codes: B60C 15/0027 with low ply turn-up, i.e. folded around the bead core and terminating at the bead core
• CPC Class Codes: B60C 15/06 Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
• CPC Class Codes: B60C 9/02 Carcasses
• CPC Class Codes: Y10T 152/10828 Chafer or sealing strips
• CPC Class Codes: Y10T 428/249939 Two or more layers

Abstract

A cylindrical body ply is mounted around a cylindrical bladder, and annular beads are set on both axial end portions of the body ply. In this state, while the spacing between both axial ends of the body ply is narrowed, an axial intermediate portion of the body ply is increased in diameter by the bladder. Subsequently, bending members formed of rigid bodies are radially moved from the inside to the outside of the body ply to bend both axial end portions of the body ply by the bending members. The bent portions of the body ply wrap around corresponding beads. With the use of the body ply manufactured in this way in a tire, the resulting tire can be reduced in the manufacturing cost and weight.

Claims

1. A method of manufacturing a pneumatic tire, comprising the steps of:

mounting a cylindrical body ply on a cylindrical surface;

setting annular beads on both axial end portions of said body ply; and

moving bending members formed of rigid bodies radially from the inside to the outside of said body ply to bend said both axial end portions of said body ply by said bending members, so that bent portions of said body ply wrap around the beads corresponding thereto.

2. The method according to claim 1, further comprising the step of pressing portions of said body ply on which said beads are disposed radially from the inside to the outside of said body ply by pressing members, prior to bending both said axial end portions of said body ply.

3. The method according to claim 2, wherein said portions of said body ply on which said beads are disposed are pressed by said pressing members to come into close contact with said beads such that said portions do not shift from said beads.

4. The method according to claim 2, wherein said pressing members press said portions of said body ply on which said beads are disposed in positions adjacent to said bending members.

5. The method according to claim 2, further comprising the step of enlarging the diameter of an axial intermediate portion of said body ply while narrowing both axial ends of said body ply, while keeping said portions of body ply, on which said beads are disposed, pressed by said pressing members.

6. The method according to claim 5, wherein said step of enlarging the diameter of an axial intermediate portion of said body ply includes supplying compressed air into an inner space of a bladder to inflate said bladder, wherein said bladder forms said cylindrical surface.

7. The method according to claim 1, wherein positions at which said beads are disposed with respect to said body ply are set such that said bent portions of said body ply are limited within a region of a wheel rim when a tire comprising said body ply is mounted on the wheel rim.

8. The method according to claim 7, wherein the positions at which said beads are disposed with respect to said body ply are set such that the positions of edges of said bent portions stay within one half of the height of a flange in said wheel rim.

9. The method according to claim 1, further comprising the step of mounting a bead insert ply to each bead prior to setting each bead on said body ply.

10. A method of manufacturing a pneumatic tire, comprising the steps of:

mounting a cylindrical body ply on a cylindrical surface;

setting annular beads on both axial end portions of said body ply;

pressing portions of said body ply on which said beads are disposed by pressing members formed of rigid bodies radially from the inside to the outside to bring said portions of said body ply on which said beads are disposed into close contact with said beads; and

enlarging the diameter of an axial intermediate portion of said body ply while narrowing the spacing between both axial ends of said body ply, wherein both said axial end portions of said body ply are bent at positions corresponding to said beads associated with the enlarged diameter of said body ply.

11. The method according to claim 10, wherein said beads are disposed near axial edges of said body ply.

12. The method according to claim 10, wherein said step of enlarging the diameter of an axial intermediate portion of said body ply includes supplying compressed air into an inner space of a bladder to inflate said bladder, wherein said bladder forms said cylindrical surface.

13. The method according to claim 10, wherein said bead is positioned with respect to said body ply such that an edge of a bent portion of said body ply is defined between the center of the width of said bead and an outer end of said bead with respect to an axial direction of said body ply.

15. The tire according to claim 14, wherein positions of said edges of said bent portions are limited within one half the height of a flange in said wheel rim.

16. The tire according to claim 14, further comprising a bead insert ply for reinforcing said bead portions.

18. The method according to claim 17, wherein said ribbon is spirally wound around a cylindrical drum with adjacent edges being in close contact with each other.

19. The method according to claim 17, wherein the arrangement of said plurality of cord arrays is determined such that said cords are arranged to form a zigzag within said ribbon.

20. The method according to claim 17, wherein different types of cords are employed in said adjacent cord arrays from each other.

21. The method according to claim 20, wherein said cords are arranged at different pitches in said adjacent cord arrays from each other.

14. A pneumatic tire comprising:

a pair of bead portions mounted on a wheel rim;

a pair of annular beads disposed in said bead portions; and

a toroidal body ply forming a skeleton of said tire, said body ply having a pair of bent portions respectively held by said beads, said bent portions having edges held in a region of said wheel rim.

17. A method of manufacturing a body ply for a pneumatic tire, comprising the steps of:

stacking a plurality of cord arrays, each made up of a plurality of parallel cords;

coating said cord arrays with a coating rubber to create an elongated ribbon which is substantially rectangular in cross section;

winding said ribbon spirally to form a cylinder;

cutting said cylinder in a direction orthogonal to a direction in which said ribbon extends to create a sheet-shaped plane body ply; and

forming a cylindrical body ply from said sheet-shaped body ply, said cords extending along the axial line of said cylindrical body ply.

22. An elongated ribbon for use in manufacturing a body ply for a pneumatic tire, said ribbon comprising:

a plurality of cord arrays arranged in stack, each said cord array made up of a plurality of parallel cords; and

a coating rubber substantially rectangular in cross section for coating said cord arrays.

23. The ribbon according to claim 22, wherein said ribbon has a width in a range of 5 to 35 mm.

24. The ribbon according to claim 22, wherein a predetermined spacing exists between two adjacent cord arrays, said spacing being 0.1 to 1.5 times the diameter of said cords.

25. The ribbon according to claim 22, wherein the cords of two adjacent cord arrays are arranged to form a zigzag.

26. The ribbon according to claim 22, wherein said cords are arranged at different pitches in two adjacent cord arrays from each other.

27. The ribbon according to claim 22, wherein two adjacent cord arrays are made up of different types of cords.

28. The ribbon according to claim 27, wherein said cords are different in ductility from each other in said two adjacent cord arrays.

29. The ribbon according to claim 22, wherein said coating rubber includes a plurality of rubber layers for coating a plurality of cord arrays, respectively, wherein two adjacent rubber layers are made of different types of rubbers from each other.