Search

EP-4438344-B1 - PNEUMATIC TIRE

EP4438344B1EP 4438344 B1EP4438344 B1EP 4438344B1EP-4438344-B1

Inventors

  • SAITO, KAZUMA
  • KITAHARA, ATSUSHI

Dates

Publication Date
20260506
Application Date
20220623

Claims (6)

  1. A pneumatic tire (1) with a tire aspect ratio of 10 to 65 and a gauge of a tread rubber of 2 to 8 mm, wherein when a condition in which the pneumatic tire (1) is mounted on an applicable rim, filled to prescribed internal pressure, and unloaded is defined as a reference condition, in the reference condition, thickness of a sidewall portion (6) in a tire radial region (R) between positions each spaced apart, from a tire maximum width position (P), by 15% of tire cross-sectional height to inner side and outer side in the tire radial direction is 1.0 to 4 mm thicker than thickness of the thinnest part of the sidewall portion (6), wherein a rubber sheet (7) is provided only in the tire radial region (R), and the mass of the sidewall portion (6) in the tire radial region (R) is 1.5% to 4.5% of the overall mass of the pneumatic tire (1).
  2. The pneumatic tire (1) according to claim 1, wherein thickness of the sidewall portion (6) at the tire maximum width position is 120% to 200% of the thickness of the thinnest part of the sidewall portion (6).
  3. The pneumatic tire (1) according to claim 1 or 2, wherein a rubber member (7) is attached to the tire radial region (R).
  4. The pneumatic tire (1) according to claim 3, wherein the rubber member (7) is attached to a tire inner surface (8).
  5. The pneumatic tire (1) according to claim 3, wherein the rubber member (7) is attached to a tire outer surface.
  6. The pneumatic tire (1) according to claim 3, wherein the rubber member (7) is disposed inside the tire (1).

Description

TECHNICAL FIELD This invention relates to a pneumatic tire. BACKGROUND In recent years, growing concern about environmental issues has led to greater demand for quieter tires. In response to this, technology has been proposed to increase the quietness of tires by making the sidewall portion thicker or providing a protrusion in the sidewall portion to suppress vibrations (see, for example, PTLs 1 and 2). JP H04 43107 A relates to a pneumatic tire which is a tire which has no allowance to the maximum width of the tire standard. A side rubber for forming the outside of a side portion between a tread for forming the road surface and a bead portion is divided into three portions in the direction of the section height H. The density of the central portion is made higher than the density of the side rubber by 10% or more. The width of the central portion, the density of which is made higher, is set to 1/10H, and the central height of the central portion is set to 1/2H. Thus, the cavity resonance and vibration of the tire can be restrained without working on the cavity in the tire. JP H07 1924 A relates to a belt layer arranged outside in the radial direction of a carcass within a tread part which is constituted by two inner and outer belt plies, and the belt cords of these belt plies are crossed each other. In an inner liner made of rubber which is arranged on the inner side of the body part of the carcass, a lining strip which is constituted by the rubber component whose rubber loss tangency is 0.15-0.25 and which is 0.15-0.55 as thick as the side wall part is attached on the inner wall surface facing the inner cavity of the tire of the inner liner at the side wall part between the inner point A to divide the distance HL which is 0.20-0.30 times the height H of the tire section and the outer point B to divide the distance HU which is 0.70-0.85 times the height H. JP 2001 047819 A relates to a pneumatic tire having a radial structure with a flatness ratio of 55% or less. An external rubber thickness of a region positioned within a range of 30 to 40% of a tire cross section height of a tire side part is 0.25 to 0.50 times a tread part rubber thickness and an external rubber thickness of a region positioned within a range of 40 to 70% of the tire cross section length is 0.50 to 0.75 times the tread part rubber thickness. In JP 2021 000873 A, a thickness of a belt cover coat of a pneumatic tire is set to be 0.70 mm-1.50 mm. A rubber for the belt cover coat is prepared by blending 20 pts.mass or more of natural rubber and 30 pts.mass or more of carbon black with 25-70 m2/g of N2SA with respect to 100 pts.mass of diene system rubber, where hardness (Hs cap) of a cap tread rubber and 300% modulus (M300bc) of the rubber for the belt cover coat satisfy a relational expression: 2.50 ≤ (Hs cap)/(M300 bc) ≤ 6.50. In JP 2020 203604 A, a thickness of an under tread rubber of a pneumatic tire is set to be 5% or more of a thickness of a cap tread rubber. The under tread rubber is formed by blending 40 pts.mass or more of natural rubber, 10 to 60 pts.mass of terminal modified butadiene rubber, 40 pts.mass or more of carbon black and 20 pts.mass or less of silica with respect to 100 pts.mass of diene rubber, where hardness of the cap tread rubber (Hs cap) and storage elastic modulus (E'ut) of the under tread rubber satisfy a relational expression: 3.5 ≤ (Hs cap)/(E'ut) ≤ 18. EP 0 614 774 A1 relates to a pneumatic radial tyre having a reduced running noise. The tyre has sidewall portions, each of which is provided on the inner surface of the airtight inner liner with a lining strip made of a rubber composition having a loss tangent of from 0.15 to 0.25. The lining strip has a radially inner edge located at a radial height of from 0.20 to 0.30 times the tyre section height and a radially outer edge located at a radial height of from 0.70 to 0.85 times the tyre section height, and the lining strip extends continuously from the inner edge to the outer edge. US 5 871 599 A relates to a pneumatic radial tire for use in truck and bus comprising a carcass reinforcing a sidewall portion and a tread, and a belt comprised of at least two belt layers, wherein when the tire is mounted onto an approved rim and inflated under an internal pressure of 0.5-1.0 kgf/cm2, a carcass line of the carcass at a radial section of the tire comprises a curve having a maximum radius of curvature in a region ranging over 10-50% of a tire sectional height and centering around a position of a maximum carcass width, and the sidewall portion has a maximum thickness in a zone corresponding to the above region. DE 10 2018 211248 A1 relates to a pneumatic vehicle tire with a tread, side walls and bead areas, with on the outside of at least one side wall in the area of the largest cross-sectional width of the pneumatic vehicle tire, a circumferential circumference serving as a rubbing strip opposite the other outer contour of the side wall has a thickness of in particu