Pneumatic tire

• US 10,639,938 B2
• Filed: 08/22/2017
• Issued: 05/05/2020
• Est. Priority Date: 11/11/2016
• Status: Active Grant

• Current Assignee: TOYO Tire & Rubber Company Limited
• Original Assignee: Toyo Tire Corporation
• Inventors: Izuhara, Yuji
• Primary Examiner(s): Dye, Robert C
• Assistant Examiner(s): Taufiq, Farah
• Application Number:
  US15/683,012
• Publication Number:
  US 20180134095A1
• Time in Patent Office: 987 Days
• Field of Search: 15220927
• CPC Class Codes: B60C 11/01 Shape of the shoulders between tread and sidewall, e.g. rounded, stepped or cantilevered
• CPC Class Codes: B60C 11/1315 having variable inclination angles, e.g. warped groove walls
• CPC Class Codes: B60C 11/1323 asymmetric
• CPC Class Codes: B60C 2011/013 provided with a recessed portion

Abstract

A pneumatic tire includes a shoulder land portion and a narrow groove in a tread surface. The narrow groove extends in the tire circumferential direction and sections the shoulder land portion into a main land portion and a sub land portion. A first groove portion extends in parallel to the tire equator surface from the tread surface toward an inner side in a tire radial direction. A second groove portion is provided closer to the inner side in the tire radial direction and the tire equator surface side than the first groove portion, and extends in parallel to the tire equator surface. A connection portion is connected to the first groove portion and the second groove portion. A groove bottom portion is provided in an end portion of the second groove portion and has a widened groove width by depressing a groove wall of the second groove portion.

Claims

1. A pneumatic tire comprising:

a shoulder land portion which extends in a tire circumferential direction; and

a narrow groove which extends in the tire circumferential direction closer to a tire equator surface side than a ground contact end of the shoulder land portion and sections the shoulder land portion into a main land portion in the tire equator surface side and a sub land portion in the ground contact end side,

the shoulder land portion and the narrow groove being provided in a tread surface,

wherein, in a cross-sectional view, a cross-sectional shape of the narrow groove in a tire width direction comprises;

a first groove portion which extends in parallel to the tire equator surface from the tread surface toward an inner side in a tire radial direction, the first groove portion having a first side wall and a second side wall which opposes the first side wall and is provided closer to the tire equator surface side than the first side wall, the first side wall and the second side wall being linear in the cross-sectional view;

a second groove portion which is provided closer to the inner side in the tire radial direction and the tire equator surface side than the first groove portion such that a width of the first groove portion does not overlap a width of the second groove portion in the tire width direction, and extends in parallel to the tire equator surface, the second groove portion having a third side wall and a fourth side wall which opposes the third side wall and is provided closer to the tire equator surface side than the third side wall, the third side wall and the fourth side wall being linear in the cross-sectional view;

a connection portion which is connected to an end portion of the first groove portion in the inner side in the tire radial direction and an end portion of the second groove portion in the tread surface side; and

a groove bottom portion which is provided in an end portion of the second groove portion in the inner side in the tire radial direction and has a widened groove width by depressing a groove wall of the second groove portion in the sub land portion side, and

wherein the cross-sectional shape of the narrow groove is configured such that the third side wall is located closer to the tire equator surface side than the second side wall in the cross-sectional view.

2. The pneumatic tire according to claim 1, wherein a distance A in the tire width direction from a groove wall of the first groove portion in the sub land portion side to the groove wall of the second groove portion in the sub land portion side is between 1.0 and 1.5 times of a distance B in the tire width direction from the groove wall of the second groove portion in the sub land portion side to an outermost end of the groove bottom portion in the tire width direction.

3. The pneumatic tire according to claim 1, wherein a distance C in the tire width direction from the outermost end of the groove bottom portion in the tire width direction to an outer wall of the sub land portion in the tire width direction is equal to or more than 3.5 times of a distance B in the tire width direction from the groove wall of the second groove portion in the sub land portion side to the outermost end of the groove bottom portion in the tire width direction.

4. The pneumatic tire according to claim 1, wherein a groove width of the first groove portion is constant in an extending direction, and both groove walls of the first groove portion are parallel to the tire equator surface.

5. The pneumatic tire according to claim 1, wherein a groove width of the second groove portion is constant in an extending direction, and both groove walls of the second groove portion are parallel to the tire equator surface.

6. The pneumatic tire according to claim 1, wherein the connection portion is formed into a linear shape.

7. The pneumatic tire according to claim 1, wherein the groove bottom portion is constructed by a circular arc, the center of which is positioned closer to the sub land portion side than the center of groove width of the second groove portion.

8. The pneumatic tire according to claim 1, wherein the groove bottom portion is constructed by a circular arc having a radius of curvature equal to or more than 1.5 mm.

9. The pneumatic tire according to claim 1, wherein an angle formed between the first groove portion and the connection portion and an angle formed between the second groove portion and the connection portion are between 80 and 170 degrees.

10. The pneumatic tire according to claim 1, wherein the narrow groove is provided in an area which is within 5% of the tread ground contact width on the basis of the ground contact end.