Motorcycle tire for uneven terrain

Patent metadata

Field	Value
Publication number	US-9290063-B2
Application number	US-201213470446-A
Country	US
Kind code	B2
Filing date	May 14, 2012
Priority date	Jun 10, 2011
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

A tire 20 includes a tread 22 , a pair of beads 26 , a carcass 28 , and a belt 30 . A ply 56 a of the carcass 28 includes: a body 58 a that extends toward each bead 26 ; and a pair of turned-up portions 60 a that extend approximately outward from the body 58 a in the radial direction. The belt 30 includes a first layer 64 a and a second layer 64 b which are layered over each other in the radial direction. Ends 68 b of the second layer 64 b are located inwardly from ends 68 a , respectively, of the first layer 64 a in the axial direction. The tread 22 includes a plurality of blocks 42.

First claim

What is claimed is:

1. A motorcycle tire for uneven terrain comprising: a tread having an outer surface which forms a tread surface; a pair of beads; a carcass which is located inwardly from the tread in a radial direction, and extends on and between each of the beads; and a belt located between the tread and the carcass, wherein
the carcass includes a first ply and a second ply which are turned up around each bead,
the first ply includes: a first body that extends from an equator plane toward each bead; and a pair of first turned-up portions that extend approximately outward from the first body in the radial direction,
the second ply includes: a second body that extends from the equator plane toward each bead; and a pair of second turned-up portions that extend approximately outward from the second body in the radial direction,
the belt includes a first layer and a second layer that extend in an axial direction and that are layered over each other in the radial direction, ends of the second layer are located inwardly from ends, respectively, of the first layer in the axial direction, and the end of the first layer is layered over the second body of the second ply,
the tread includes a plurality of blocks that extend approximately outward in the radial direction, separated from one another by grooves, some of which blocks may have recesses located in their surface, wherein the plurality of blocks are arranged so as to be intermittently divided from one another in a circumferential direction and an axial direction, and the plurality of blocks include shoulder blocks that are located on outer sides in the axial direction, wherein a land is defined as an area of a tread surface which is not recessed and a sea is defined as an area of the tread which is constituted by a groove and a land to sea ratio is equal to or greater than 10% and equal to or less than 30%,
a portion of each of the first turned-up portions extends beyond a corresponding one of the ends of the second turned-up portions, the portion of each of the first turned-up portions is layered over the first layer, each of the first turned-up portions is not layered over the second layer, ends of the first turned-up portions are located close to the ends, respectively, of the second layer, and each of the second turned-up portions are located close to the ends, respectively, of the first layer, inwardly from the shoulder blocks in the radial direction,
the ends of the first turned-up portions and the ends of the second turned-up portions and the ends of the first layer and the ends of the second layer are located between ends of the tread surface and ends of the side surfaces of the shoulder blocks, respectively, in the radial direction,
each of the beads includes a core and an apex that extends outward from the core in the radial direction, the apex is formed of a crosslinked rubber composition, a complex elastic modulus of the apex is less than or equal to 40 MPa, a loss tangent of the apex is less than or equal to 0.10, and the second body is brought into contact with each of the second turned-up portions at an outer side of the apex in the radial direction, and
said tire is suitable for use when an internal air pressure of the tire is 80 kPa.

2. The motorcycle tire for uneven terrain according to claim 1 , wherein a layered length by which each of the first turned-up portions is layered over the first layer is greater than or equal to 5 mm, and is not greater than 20 mm.

3. The motorcycle tire for uneven terrain according to claim 2 , wherein the layered length is greater than or equal to 7 mm and is not greater than 18 mm.

4. The motorcycle tire for uneven terrain according to claim 1 , wherein a distance from each of the ends of the first turned-up portions to a corresponding one of the ends of the second layer is greater than or equal to 0.1 mm, and is not greater than 5 mm.

5. The motorcycle tire for uneven terrain according to claim 1 , wherein a distance from each of the ends of the second turned-up portions to a corresponding one of the ends of the first layer is greater than or equal to 0.1 mm and is not greater than 5 mm.

6. The motorcycle tire for uneven terrain according to claim 1 , wherein the rubber composition of the apex comprises a base rubber composed of at least two members selected from the group consisting of a natural rubber, a butadiene rubber, and a styrene-butadiene rubber.

7. The motorcycle tire for uneven terrain according to claim 1 , wherein the rubber composition of the apex comprises a base rubber composed of a natural rubber, a butadiene rubber, and a styrene-butadiene rubber.

8. The motorcycle tire for uneven terrain according to claim 1 , wherein each of the first ply and the second ply includes multiple cords formed of nylon fibers or polyester fibers.

Assignees

• Hikita Masahiro
• Sumitomo Rubber Ind

Inventors

• Hikita Masahiro

Classifications

• B60C15/0603 Primary

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

• B60C15/0045

  with ply turn-up up to the belt edges, i.e. folded around the bead core and extending to the belt edges · CPC title

• B60C2015/0614

  characterised by features of the chafer or clinch portion, i.e. the part of the bead contacting the rim · CPC title

• B60C2015/009

  Height of the carcass terminal portion defined in terms of a numerical value or ratio in proportion to section height · CPC title

• B60C9/08

  the cords extend transversely from bead to bead, i.e. radial ply (B60C9/07 takes precedence) · CPC title