Motorcycle tire for running on rough terrain

Patent metadata

Field	Value
Publication number	US-9375982-B2
Application number	US-201213529323-A
Country	US
Kind code	B2
Filing date	Jun 21, 2012
Priority date	Jul 13, 2011
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

A motorcycle tire for running on rough terrain comprises a tread portion provided with a plurality of blocks defining a block pattern. The blocks include center blocks whose centroids of their top surfaces are disposed within a center region of the tread portion defined as being centered on the tire equator and having a developed width of 25% of a developed tread width. The top surface of each of the center blocks is provided with an axially extending edge extending straight and parallel with the tire axial direction, and arc edges curved convexly toward the centroid of the top surface and disposed on both sides of the axially extending edge in the tire axial direction.

First claim

The invention claimed is:

1. A motorcycle tire for running on rough terrain comprising
a tread portion provided with a plurality of blocks defining a block pattern, the blocks including center blocks whose centroids of their top surfaces are disposed within a center region of the tread portion defined as being centered on the tire equator and having a developed width of 25% of a developed tread width, wherein the top surface of each of the center blocks is provided with an axially extending edge which extends straight and parallel with the tire axial direction on its each side in the tire circumferential direction, and a pair of arc edges which are curved convexly toward the centroid of the top surface and disposed on both sides of the axially extending edge in the tire axial direction;
shoulder blocks whose centroids of their top surfaces are within shoulder regions defined as extending toward the tire equator from the respective tread edges and each having a developed width of 12.5% of the developed tread width, wherein the top surface of each of the shoulder blocks is provided with a pair of axially extending edges which extend straight and parallel with the tire axial direction on its both sides in the tire circumferential direction, an axially outside circumferentially extending edge which extends straight and parallel with the tire circumferential direction between the axially outer ends of the axially extending edges, an axially inside circumferentially extending edge which extends straight and parallel with the tire circumferential direction on its tire equator side; and a pair of arc edges which are curved convexly toward the centroid on both sides of the axially inside circumferentially extending edge in the tire circumferential direction; and
middle blocks whose centroids of their top surfaces are within middle regions of the tread portion defined between the center region and the shoulder regions, wherein the top surface of each of the middle blocks is provided with an axially inside circumferentially extending edge which extends straight and parallel with the tire circumferential direction on its tire equator side, an axially outside circumferentially extending edge which extends straight and parallel with the tire circumferential direction on its axially outside a pair of axially extending edges which extend straight and parallel with the tire axial direction on its both sides in the tire circumferential direction, a pair of arc edges which are curved convexly toward the centroid on both sides of the axially inside circumferentially extending edge in the tire circumferential direction, and a pair of oblique edges extending straight and obliquely with respect to the tire circumferential direction on both sides of the axially outside circumferentially extending edge in the tire circumferential direction.

2. The motorcycle tire for running on rough terrain according to claim 1 , wherein in each of the center blocks, the axial length of the axially extending edge is 26 to 46% of the maximum axial width of the top surface, and the arc edges each have a radius of curvature which is 22 to 42% of the maximum circumferential length of the top surface.

3. The motorcycle tire for running on rough terrain according to claim 1 or 2 , wherein
said center blocks include a plurality of tied center block groups each consisting of at least two axially arranged center blocks each connected to the next with a tie bar, and
the tied center block groups are arranged circumferentially of the tire at intervals so that at least one group always exists in the ground contacting patch of the tire during running.

4. The motorcycle tire for running on rough terrain according to claim 1 , wherein
the circumferential length of the axially inside circumferentially extending edge of the middle block is 27 to 47% of the maximum circumferential length of the top surface of the middle block, and
the arc edges of the middle block each have a radius of curvature of 22 to 42% of the maximum axial width of the top surface of the middle block.

5. The motorcycle tire for running on rough terrain according to claims 1 or 4 , wherein
the middle blocks in each said middle region are arranged circumferentially of the tire so that their centroids are disposed at at least two different axial positions.

6. The motorcycle tire for running on rough terrain according to claim 1 , wherein
the axial distance from the tire equator to the centroid of each said middle block is 38 to 68% of one half of the developed tread width.

7. The motorcycle tire for running on rough terrain according to claim 1 , wherein
with respect to the circumferential positions of the centroids of the middle blocks, the middle blocks in one of the middle regions are respectively aligned with the middle blocks in the other middle region so that the angle of a straight line drawn between the centroids of the aligned middle blocks is not more than 10 degrees with respect to the tire axial direction.

8. The motorcycle tire for running on rough terrain according to claim 1 , wherein
the circumferential length of the axially inside circumferentially extending edge of the shoulder block is 26 to 46% of the maximum circumferential length of the top surface of the shoulder block, and
the arc edges of the shoulder blocks each have a radius of curvature of 29 to 49% of the maximum axial width of the top surface of the shoulder block.

9. The motorcycle tire for running on rough terrain according to claim 1 , wherein
with respect to the circumferential positions of the centroids of the shoulder blocks, the shoulder blocks in one of the shoulder regions are respectively aligned with the shoulder blocks in the other shoulder region so that the angle of a straight line drawn between the centroids of the aligned shoulder blocks is not more than 8 degrees with respect to the tire axial direction.

10. The motorcycle tire of claim 1 , wherein a land ratio of the top surface of the blocks to the gross area of the tread (SL/S) is 6 -30%.

Assignees

• Ishida Shingo
• Sumitomo Rubber Ind

Inventors

• Ishida Shingo

Classifications

• B60C2200/10

  for motorcycles, scooters or the like · CPC title

• B60C11/1376

  Three dimensional block surfaces departing from the enveloping tread contour · CPC title

• B60C11/033

  by the void or net-to-gross ratios of the patterns · CPC title

• B60C2200/14

  for off-road use · CPC title

• B60C11/11 Primary

  in which the raised area of the pattern consists only of isolated elements, e.g. blocks (B60C11/12, B60C11/13 take precedence) · CPC title