Pneumatic tire

Patent metadata

Field	Value
Publication number	US-10850565-B2
Application number	US-201515312595-A
Country	US
Kind code	B2
Filing date	May 19, 2015
Priority date	May 20, 2014
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A pneumatic tire includes a tread portion, sidewall portions, bead portions, and has at least one carcass layer disposed between the pair of bead portions. The ratio SW/OD between the total tire width SW and the tire external diameter OD satisfies the relationship SW/OD≤0.3. A first region A is defined between a pair of first boundary lines (L1, L1), second regions B are defined between a first boundary line (L1) and a second boundary line (L2), and third regions C are defined on the bead toe side of the second boundary lines (L2). Defining SA, SB, and SC as the cross-sectional area (mm2) of the first region A to the third region C, and defining the peripheral lengths (mm) of the first region A to third region C along the tire inner surface as a, b, and c, respectively, the relationship 7.5≤SA/a≤11.5 is satisfied.

First claim

The invention claimed is:

1. A pneumatic tire, comprising: a tread portion extending in a tire circumferential direction in an annular shape; a pair of sidewall portions disposed on either side of the tread portion; a pair of bead portions disposed on an inside in a tire radial direction of the sidewall portions; and at least one layer of a carcass layer disposed between the pair of bead portions; wherein
a ratio SW/OD of a total tire width SW and a tire outer diameter OD satisfies a relationship SW/OD≤0.3, the total tire width SW being set in a range from 125 mm to 185 mm and the tire outer diameter OD being set in a range from 650 mm to 850 mm;
in a tire meridian cross-section, a contour of the tread portion that forms a tread profile includes side arcs located on outermost sides in a tire width direction of the tread portion, and shoulder arcs located on an inner side in the tire width direction of the side arcs; a pair of first boundary lines is defined passing through an intersection point of an extension line of the side arcs and an extension line of the shoulder arcs and perpendicular to a tire inner surface; each sidewall portion has a rim check line extending in the tire circumferential direction; in a tire meridian cross-section, a pair of second boundary lines is defined passing through the rim check lines and perpendicular to the tire inner surface; a first region is partitioned between the pair of first boundary lines; a second region is partitioned between the first boundary line and a second boundary line; a third region is partitioned on a bead toe side of the second boundary line; when cross-sectional areas (mm 2 ) of the first region through third region are SA, SB, and SC respectively, and peripheral lengths (mm) of the first region through third region along the tire inner surface are a, b, and c respectively, a ratio SA/a satisfies a relationship 7.5≤SA/a≤11.5;
the tread portion has a tread pattern formed by grooves, and a groove area ratio GR in a ground contact region of the tread pattern is 25% or less;
a linear density of carcass cords of the carcass layer is from 1200 dtex/2 to 1300 dtex/2, and a cord count per 50 mm unit width of the carcass layer is from 55 to 70 cords;
a bead filler is disposed on an outer periphery side of each of the bead cores, a height of the bead filler in the tire radial direction being less than a height of the rim check line in the tire radial direction; and
at least one inclined reinforcing layer including a plurality of reinforcing cords inclining with respect to the tire circumferential direction is disposed on an outer circumferential side of the carcass layer in the tread portion, an inclination angle of the reinforcing cords of the at least one inclined reinforcing layer with respect to the tire circumferential direction being from 40° to 45°.

2. The pneumatic tire according to claim 1 , wherein a ratio SB/b satisfies a relationship 2.0≤SB/b≤6.0.

3. The pneumatic tire according to claim 1 , wherein a ratio SC/c satisfies a relationship 4.0≤SC/c≤8.0.

4. The pneumatic tire according to claim 1 , wherein the grooves formed in the tread portion include at least one main groove, and when a maximum groove depth of the main groove is GDmax, 3.0 mm≤GDmax≤6.0 mm.

5. The pneumatic tire according to claim 1 , wherein the groove area ratio GR in the ground contact region of the tread pattern satisfies 12%≤GR≤19%.

6. The pneumatic tire according to claim 1 , further comprising an air penetration preventing layer with an air penetration coefficient of from 30×10 −12 cc·cm/cm 2 ·sec·cmHg to 50×10 −12 cc·cm/cm 2 ·sec·cmHg in a tire interior and/or on the tire inner surface along the carcass layer.

7. The pneumatic tire according to claim 1 , further comprising an air penetration preventing layer with an air penetration coefficient of 50×10 −12 cc·cm/cm 2 ·sec·cmHg or less in a tire interior and/or on the tire inner surface along the carcass layer.

8. The pneumatic tire according to claim 7 , wherein the air penetration preventing layer is formed from a thermoplastic resin or a thermoplastic elastomer composition in which a thermoplastic resin and an elastomer are blended.

9. The pneumatic tire according to claim 1 , wherein at least one circumferential reinforcing layer extending along the tire circumferential direction is arranged on the outer circumferential side of the inclined reinforcing layer.

10. The pneumatic tire according to claim 9 , wherein the circumferential reinforcing layer is configured from a composite material with reinforcing cords oriented in the tire circumferential direction embedded in rubber.

11. The pneumatic tire according to claim 10 , wherein the reinforcing cords of the circumferential reinforcing layer are organic fiber cords.

Assignees

• Yokohama Rubber Co Ltd

Inventors

• Minami Yuji
• Shimizu Masatoshi

Classifications

• B60C2009/2019

  comprising cords at an angle of 30 to 60 degrees to the circumferential direction · CPC title

• B60C2009/0441

  Density in width direction · CPC title

• B60C2009/0425

  Diameters of the cords; Linear density thereof · CPC title

• B60C9/22

  the plies being arranged with all cords disposed along the circumference of the tyre · CPC title

• B60C2011/0341

  Circumferential grooves · CPC title