Motorcycle tire

Patent metadata

Field	Value
Publication number	US-10654319-B2
Application number	US-201715688223-A
Country	US
Kind code	B2
Filing date	Aug 28, 2017
Priority date	Aug 30, 2016
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

A motorcycle tire 1 comprises a tread portion 2, sidewall portions 3, bead portions 4, a carcass 6 extending between the bead portions, and a tread reinforcing layer 7 disposed radially outside the carcass in the tread portion. The tread reinforcing layer 7 is composed of a helically wound strip 10 of parallel reinforcing cords 11 coated with topping rubber 12. The winding pitch Pm of the strip 10 in middle parts Mi of the tread reinforcing layer is less than the winding pitch Pc of the strip 10 in a central part Cr, and less than the winding pitch Ps of the strip 10 in shoulder parts Sh.

First claim

The invention claimed is:

1. A motorcycle tire comprising:
a tread portion having a tread face,
a pair of sidewall portions,
a pair of bead portions,
a carcass extending between the bead portions through the tread portion and the sidewall portions, and
a tread reinforcing layer disposed radially outside the carcass in the tread portion, and having a developed axial width (Wa) of not less than 75% of a developed tread width (TWe) between tread edges of the tread face, each measured along the tread face in a tire meridian section,

wherein
the tread reinforcing layer is made up of a first halved reinforcing layer disposed on one side of the tire equator, and a second halved reinforcing layer disposed on the other side of the tire equator,
the first halved reinforcing layer is composed of a helically-wound first strip of parallel reinforcing cords coated with topping rubber,
the second halved reinforcing layer is composed of a helically-wound second strip of parallel reinforcing cords coated with topping rubber,
the reinforcing cords of the first strip include an axially inside first reinforcing cord and an axially outside second reinforcing cord disposed axially outside the axially inside first reinforcing cord,
the reinforcing cords of the second strip include an axially inside first reinforcing cord and an axially outside second reinforcing cord disposed axially outside the axially inside first reinforcing cord,
in each of the first strip and the second strip, an initial elongation percentage a2 of the axially outside second reinforcing cord is greater than an initial elongation percentage a1 of the axially inside first reinforcing cord, wherein the initial elongation percentage of a reinforcing cord is an elongation of the cord in terms of a percentage when a load applied to the cord is increased from 2.5N to 49N,
the first strip and second strip are helically wound from the tire equator to the respective edges of the tread reinforcing layer,
in each of the first halved reinforcing layer and the second halved reinforcing layer, the first reinforcing cord and the second reinforcing cord are alternately arranged from the tire equator to the respective edges of the tread reinforcing layer, and
the winding pitch P of the helically-wound first and second strips is larger in a central part and axially outer shoulder parts of the tread reinforcing layer than in middle parts of the tread reinforcing layer between the central part and the shoulder parts.

2. The motorcycle tire according to claim 1 , wherein the winding pitch P is larger in the central part than in the axially outer shoulder parts.

3. The motorcycle tire according to claim 1 , wherein
a pitch ratio P/La of the winding pitch P to a distance La between the reinforcing cords in each strip which are closest to respective two sides of the strip is
162% to 260% in the central part,
129% to 162% in the middle parts, and
140% to 240% in the shoulder parts.

4. The motorcycle tire according to claim 3 , wherein said distance La between the reinforcing cords is in a range from 2.0 to 8.2 mm.

5. The motorcycle tire according to claim 1 , wherein
a width of the central part measured along the tread face is 10% to 52% of a tread reinforcing layer width which is a width of the tread reinforcing layer measure along the tread face,
a width of each of the middle parts measured along the tread face is 17% to 38% of the tread reinforcing layer width, and
a width of each of the shoulder parts measured along the tread face is 7% to 28% of the tread reinforcing layer width.

6. The motorcycle tire according to claim 1 , wherein the initial elongation percentage a1 of the axially inside first reinforcing cord is in a range from 50% to 90% of the initial elongation percentage a2 of the axially outside second reinforcing cord.

7. The motorcycle tire according to claim 1 , wherein
each of the first strip and the second strip includes at least one reinforcing cord between the axially inside first reinforcing cord and the axially outside second reinforcing cord, and
the initial elongation percentages of the reinforcing cords in each strip are gradually decreased from the axially outermost reinforcing cord to the axially innermost reinforcing cord.

8. The motorcycle tire according to claim 1 , wherein
each of the first strip and the second strip includes an additional reinforcing cord between the axially inside first reinforcing cord and the axially outside second reinforcing cord, and
the initial elongation percentages of the additional reinforcing cord is the same as the initial elongation percentage a1 of the axially inside first reinforcing cord.

9. The motorcycle tire according to claim 1 , wherein
each of the first strip and the second strip includes an additional reinforcing cord between the axially inside first reinforcing cord and the axially outside second reinforcing cord, and
the initial elongation percentages of the additional reinforcing cord is the same as the initial elongation percentage a2 of the axially outside second reinforcing cord.

Assignees

• Sumitomo Rubber Ind

Inventors

• Tochiki Yuki

Classifications

• B60C2200/10

  for motorcycles, scooters or the like · CPC title

• B29D2030/383

  Chemical treatment of the reinforcing elements, e.g. cords, wires and filamentary materials, to increase the adhesion to the rubber · CPC title

• B60C2009/2252

  Physical properties or dimension of the zero degree ply cords · CPC title

• B60C9/0042 Primary

  Reinforcements made of synthetic materials · CPC title

• B60C9/2204

  obtained by circumferentially narrow strip winding · CPC title