Pneumatic tire

Patent metadata

Field	Value
Publication number	US-10071597-B2
Application number	US-201414913600-A
Country	US
Kind code	B2
Filing date	Aug 27, 2014
Priority date	Sep 10, 2013
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

[Solution] A profile OL of the tire 2 includes a ground-contact surface 46 and a pair of side surfaces 48. In the profile OL, a zone from a point PB to a point PW is formed by three arcs. The arcs are a first arc, a second arc that extends almost outward from the first arc in the radial direction, and a third arc that extends almost outward from the second arc further in the radial direction. A ratio of a radius R2 of curvature of the second arc to a radius R1of curvature of the first arc is greater than or equal to 1.45 and not greater than 3.26. A ratio of a radius R3 of curvature of the third arc to the radius R1 of curvature of the first arc is greater than or equal to 0.45 and not greater than 0.56. Each sidewall 8 of the tire 2 has a first recess 50a and a second recess 50b that are recessed inward from the side surface 48.

First claim

The invention claimed is:

1. A pneumatic tire comprising:
a tread;
a pair of sidewalls that extend from ends, respectively, of the tread almost inward in a radial direction;
a pair of clinches disposed inward of the sidewalls, respectively, in the radial direction;
a pair of beads disposed inward of the clinches, respectively, in an axial direction; and
a carcass extended, along inner sides of the tread and the sidewalls, on and between one of the beads and the other of the beads,

wherein
a profile of the tire includes a ground-contact surface, and a pair of side surfaces that extend from the ground-contact surface almost inward in the radial direction,
a maximum value of a distance, in the axial direction, between both the side surfaces represents a maximum width of the tire,
a boundary between the ground-contact surface and each side surface is a point PB;
a point, on the side surface, representing the maximum width is a point PW;
an imaginary straight line that extends through each point PW in the axial direction is a first reference line;
a length, in the radial direction, from the first reference line to an equator is a first reference length;
a point, on the side surface, which is disposed outward of the point PW in the radial direction, and which is distant from the first reference line in the radial direction, by a length corresponding to ⅓ of the first reference length, is a point PU 1 ;
a point, on the side surface, which is disposed outward of the point PU 1 in the radial direction, and which is distant from the point PU 1 in the radial direction, by a length corresponding to ⅓ of the first reference length, is a point PU 2 ;
a point, on the side surface, disposed at a mid-position between the point PU 2 and the point PU 1 in the radial direction, is a point PU 3 ;
a point, on the side surface, disposed at a mid-position between the point PU 2 and the point PB in the radial direction, is a point PU 4 ;
an end point of the side surface is a point PT;
an imaginary straight line that extends through each point PT in the axial direction is a second reference line;
a length, in the radial direction, from the second reference line to the equator represents a cross-sectional height of the tire;
a length, in the radial direction, from the second reference line to the point PW is a second reference length;
a point, on the side surface, which is disposed inward of the point PW in the radial direction, and which is distant from the first reference line in the radial direction, by a length corresponding to ⅓ of the second reference length, is a point PL 1 ;
a point, on the side surface, which is disposed inward of the point PL 1 in the radial direction, and which is distant from the first reference line in the radial direction, by a length corresponding to 11/20 of the second reference length, is a point PL 2 ;
a thickness of each sidewall at the point PW is a reference thickness,
a zone from the point PB to the point PW on each side surface is formed by three main arcs,
the main arcs are a first main arc, a second main arc that extends almost outward from the first main arc in the radial direction, and a third main arc that extends almost outward from the second main arc further in the radial direction,
the first main arc extends through the point PW and the point PU 1 ,
the second main arc extends through the point PU 1 , the point PU 3 , and the point PU 2 ,
the third main arc extends through the point PU 2 , the point PU 4 , and the point PB,
a ratio of a radius RM 2 of curvature of the second main arc to a radius RM 1 of curvature of the first main arc is greater than or equal to 1.45 and not greater than 3.26,
a ratio of a radius RM 3 of curvature of the third main arc to the radius RM 1 of curvature of the first main arc is greater than or equal to 0.45 and not greater than 0.56,
an extension line from the first main arc extends through an imaginary point PU 5 defined such that the imaginary point PU 5 and the point PU 1 are line-symmetric with respect to the first reference line,
a zone from the point PW to the point PL 2 on each side surface is formed by a fourth main arc,
the fourth main arc extends through the point PW, the point PL 1 , and the point PL 2 ,
an extension line from the fourth main arc extends through an imaginary point PL 3 defined such that the imaginary point PL 3 and the point PL 1 are line-symmetric with respect to the first reference line,
each sidewall has a first recess and a second recess that are recessed inward from the side surface,
the first recess is disposed outward of the point PW in the radial direction,
the second recess is disposed inward of the point PW in the radial direction,
a ratio of a length SU, in the radial direction, from the first reference line to a bottom of the first recess, relative to the cross-sectional height, is greater than or equal to 0.08 and not greater than 0.24,
a ratio of a length SL, in the radial direction, from the first reference line to a bottom of the second recess, relative to the cross-sectional height, is greater than or equal to 0.08 and not greater than 0.24,
a ratio of a depth TU of the first recess to the reference thickness is greater than or equal to 0.16 and not greater than 0.48, and
a ratio of a depth TL of the second recess to the reference thickness is greater than or equal to 0.16 and not greater than 0.48.

2. The pneumatic tire according to claim 1 , wherein
a contour of the first recess is formed by two secondary arcs,
the secondary arcs are a first secondary arc, and a second secondary arc that extends almost outward from the first secondary arc in the radial direction,
a point, on an outer surface of each sidewall, disposed at a mid-position between the point PW and the bottom of the first recess in the radial direction, is a point PU 6 ,
a point, on the outer surface of each sidewall, disposed at a mid-position between the point PU 3 and the bottom of the first recess in the radial direction, is a point PU 7 ,
the first secondary arc extends through the point PW, the point PU 6 , and the bottom of the first recess,
the second secondary arc extends through the bottom of the first recess, the point PU 7 , and the point PU 3 ,
a ratio of a radius RS 1 of curvature of the first secondary arc to the radius RM 1 of curvature of the first main arc is greater than or equal to 0.45 and not greater than 1 18, and
a ratio of a radius RS 2 of curvature of the second secondary arc to the radius RM 1 of curvature of the first main arc is greater than or equal to 0.63 and not greater than 1.54.

3. The pneumatic tire according to claim 1 , wherein
a contour of the second recess is formed by two secondary arcs,
the secondary arcs are a third secondary arc, and a fourth secondary arc that extends almost inward from the third secondary arc in the radial direction,
a point, on the outer surface of each sidewall, disposed at a mid-position between the point PW and the bottom of the second recess in the radial direction, is a point PL 4 ,
a point, on the outer surface of each sidewall, disposed at a mid-position between the point PL 2 and the bottom of the second recess in the radial direction, is a point PL 5 ,
the third secondary arc extends through the point PW, the point PL 4 , and the bottom of the second recess,
the fourth secondary arc extends through the bottom of the second recess, the point PL 5 , and the point PL 2 ,
a ratio of a radius RS 3 of curvature of the third secondary arc to a radius RM 4 of curvature of the fourth main arc is greater than or equal to 0.39 and not greater than 0.91, and
a ratio of a radius RS 4 of curvature of the fourth secondary arc to the radius RM 4 of curvature of the fourth main arc is greater than or equal to 0.65 and not greater th

Assignees

• Sumitomo Rubber Ind

Inventors

• Tomita Shintaro
• Tanaka Susumu
• Asano Kazuo

Classifications

• B60C11/00

  Tyre tread bands; Tread patterns; Anti-skid inserts · CPC title

• B60C9/02

  Carcasses · CPC title

• B60C13/003

  characterised by sidewall curvature · CPC title

• B60C13/02

  Arrangement of grooves or ribs · CPC title

• B60C9/0292

  Carcass ply curvature (sidewall curvature B60C13/003) · CPC title