Pneumatic tire

Patent metadata

Field	Value
Publication number	US-10479145-B2
Application number	US-201615267530-A
Country	US
Kind code	B2
Filing date	Sep 16, 2016
Priority date	Oct 14, 2015
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

A tire 2 includes: a pair of beads 10 including cores 28; chafers 22, disposed near the beads 10, which are brought into contact with a rim; an inner liner 18 disposed inward of a carcass 32 in an axial direction; and an insulation 20 disposed between the carcass 32 and the inner liner 18 in the axial direction. The chafers 22 include bottom surfaces 22a that are brought into contact with the rim in portions inward of the cores 28 in a radial direction. The insulation 20 includes insulation lower portions 20a disposed between the cores 28 and the bottom surfaces 22a of the chafers 22 in the radial direction. The inner liner 18 includes inner liner lower portions 18a disposed between the cores 28 and the bottom surfaces 22a of the chafers 22 in the radial direction.

First claim

What is claimed is:

1. A pneumatic tire comprising:
a pair of beads each including a core;
a carcass extended, along inner sides of a tread and sidewalls, on and between one of the beads and the other of the beads;
chafers, one in each bead, which are intended to be brought into contact with a normal rim;
an inner liner disposed inward of the carcass in an axial direction;
an insulation disposed between the carcass and the inner liner in the axial direction, and cushion layers, one in each bead;
wherein the chafers include bottom surfaces that are intended to be brought into contact with the rim in respective bead portions inward of the respective cores in a radial direction,
wherein the insulation includes insulation lower portions disposed between the respective cores and the respective bottom surfaces of the chafers in the radial direction,
wherein the inner liner includes inner liner lower portions disposed between the respective cores and the respective bottom surfaces of the chafers in the radial direction,
wherein the inner liner is formed of crosslinked rubber, the insulation is formed of a crosslinked rubber, and a compressive elastic modulus Eβ of the insulation rubber is less than a compressive elastic modulus Eγ of the inner liner rubber;
wherein the cushion layers are formed of soft crosslinked rubber,
wherein the cushion layers are layered inward of the respective cores in the radial direction and outward of the respective insulation lower portions in the radial direction,
wherein a compressive elastic modulus Eα of the cushion layer rubber is less than each of the compressive elastic modulus Eβ of the insulation rubber and the compressive elastic modulus Eγ of the inner liner rubber; and
wherein in portions that are inward of the respective cores in the radial direction, a thickness Lα of each cushion layer is greater than a thickness Lβ of each insulation lower portion,
wherein the thickness Lβ of each insulation lower portion is greater than a thickness Lγ of each inner liner lower portion, the thicknesses Lβ and Lγ being measured along a straight line L 2 passing through the central position in the axial direction of the respective core bottom surface.

2. The tire according to claim 1 , wherein the inner liner lower portions extend from portions that are axially inward of the respective cores to portions that are axially outward thereof.

3. The tire according to claim 2 , wherein each bead includes a bead heel, a contour of each bead heel is formed into an arc shape, and
when Pr represents a radially outer end of the arc shape,
the inner liner lower portions extend outward of the outer end Pr in the radial direction, in portions that are axially outward of the respective cores.

4. The tire according to claim 1 , wherein each bead includes a bead heel, a contour of each bead heel is formed into an arc shape, and
a radius R of curvature of the arc shape is greater than or equal to 7 mm, and not greater than 15 mm.

5. The tire according to claim 1 , wherein
the compressive elastic modulus Eβ of the insulation rubber is higher than or equal to 2.5 MPa, and not higher than 3.0 MPa, and
the compressive elastic modulus Eγ of the inner liner rubber is higher than or equal to 3.5 MPa, and not higher than 5.0 MPa.

6. The tire according to claim 1 , wherein a thickness L, in the radial direction, from the bottom surface of each chafer to a bottom surface of a corresponding one of the cores, measured along a straight line L 1 passing through the central position in the axial direction of the core bottom surface, is greater than or equal to 4 mm, and not greater than 8 mm.

7. The tire according to claim 1 , wherein, when the tire is mounted on the normal rim and inflated to a normal internal pressure, a ratio of a change amount in fastening force to a change amount in an amount of compressive deformation is greater than or equal to 1.5 kN/mm, and not greater than 2 kN/mm in a case where the fastening force is from 3 kN to 4 kN, the compressive deformation being the difference between the thickness L before the tire is mounted on the normal rim and inflated to the normal internal pressure and the thickness L′ after the tire is mounted on the normal rim and inflated to the normal internal pressure, the thicknesses L and L′ being measured in the radial direction from the bottom surface of each chafer to a bottom surface of a corresponding one of the cores along the straight line L 1 passing through the central position in the axial direction of the core bottom surface.

8. The tire according to claim 1 , wherein
each core is formed by a bead wire being wound in a circumferential direction, and
the bead wire is wound so as to overlap in both the radial direction and the axial direction.

9. The tire according to claim 1 , wherein the compressive elastic modulus Eα of the cushion layer rubber is higher than or equal to 1.0 MPa, and not higher than 2.0 MPa.

10. The tire according to claim 1 , wherein, in portions that are inward of the respective cores in the radial direction, a ratio of a thickness Lα of each cushion layer to a thickness L, in the radial direction, from the bottom surface of a corresponding one of the chafers to a bottom surface of a corresponding one of the cores, is greater than or equal to 0.5, the thicknesses L and Lα being measured along a straight line L 2 passing through the central position in the axial direction of the respective core bottom surface.

Assignees

• Sumitomo Rubber Ind

Inventors

• Osawa Takuya
• Ueda Kenji

Classifications

• B60C15/0635

  using chippers between the carcass layer and chafer rubber wrapped around the bead · CPC title

• B60C15/0603 Primary

  characterised by features of the bead filler or apex · CPC title

• B60C15/024

  Bead contour, e.g. lips, grooves, or ribs · CPC title

• B60C15/0009 Primary

  features of the carcass terminal portion · CPC title

• B60C2015/044

  characterised by a wrapping layer · CPC title