JP4301618B2 - Pneumatic radial tire - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic radial tire, and in particular, a bead core provided in a pair of left and right bead parts, and extends from the crown part to both bead parts through both side parts and wound around the bead core. A carcass ply comprising a radial cord layer moored to the bead portion, a belt disposed radially outward of the crown portion of the carcass ply, and a tread disposed radially outward of the belt. Related to pneumatic radial tires.
[0002]
[Prior art]
Pneumatic tires do not stand upright when mounted on a vehicle, but are often attached in the form of an outward or inward opening that slightly falls outward or inward. This angle, that is, the angle formed by the center line of the tire (wheel) and the vertical line is called the camber angle, and it is said that it is a positive camber when it falls to the outside and a negative camber when it falls to the inside. Usually, in the case of a passenger car, the tire is mounted in the form of an inward opening and has a negative camber. The purpose of attaching the tire to the vehicle with a camber angle is to alleviate the impact from the road surface or to ease the steering. Usually, camber is attached by independent suspension at the front, but in all-wheel independent suspension vehicles, the camber angle is also often attached to the rear.
When a pneumatic tire is attached to a vehicle with a negative camber attached, the ground pressure is higher when the vehicle is installed than the side located on the inner side compared to the side located on the outer side. Wear. Such uneven wear (non-uniform wear) phenomenon occurs remarkably in so-called super flat pneumatic tires having an aspect ratio defined by the ratio of the tire cross-sectional height to the tire cross-sectional width of 55% or less.
[0003]
[Problems to be solved by the invention]
When the phenomenon of uneven wear (non-uniform wear) occurs in which only the inner tread rubber is worn at an early stage as described above, the outer groove remains sufficiently even if the inner groove is worn away and is in a dangerous state. Therefore, it is often not noticed that it is time to change tires. Even if the inner groove is worn out and is in a dangerous state, if the vehicle continues to run as it is, there is a problem that the vehicle naturally falls into a dangerous situation such as a slip.
[0004]
An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a tread rubber located on the inside when the vehicle is mounted, which is generated when the vehicle is mounted on a passenger car having a normal negative camber. It is an object of the present invention to provide a pneumatic tire for a passenger car that prevents or suppresses the phenomenon of uneven wear (non-uniform wear) that wears early compared to the outside.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a pneumatic tire according to the present invention includes a bead core provided on a pair of right and left bead parts, and extends from the crown part to both bead parts via both side parts, and is wound around the bead core. A carcass ply formed of a radial cord layer that is rotated and moored at the bead portion; a belt disposed radially outward of the crown portion of the carcass ply; and a tread disposed radially outward of the belt; (1) A large number of inclined grooves extending in the circumferentially inclined direction are arranged at intervals in the circumferential direction on both sides of the tread, and (2) the tire is mounted on the vehicle. the groove depth of the outer inclined groove located on the outer side when mounted is, rather 0.5 to about 1mm shallow than the groove depth of the inner inclined groove located on the inner side, (3) the bell from the groove bottom of the inclined groove A pneumatic radial tire which is a distance to a constant.
[0006]
In the pneumatic radial tire of the present invention, the aspect ratio defined by the ratio of the tire cross-sectional height to the tire cross-sectional width is 55% or less, and the outer inclined groove has a relatively shallow groove depth. It is preferable that the groove and the deep groove are formed , and the groove having the relatively shallow groove and the deep groove forming the outer inclined groove are alternately arranged in the circumferential direction.
[0007]
The pneumatic radial tire of the present invention has the above-described configuration. In particular, (1) A large number of inclined grooves extending in the direction inclined in the circumferential direction are spaced apart in the circumferential direction on both sides of the tread. (2) When the tire is mounted on the vehicle, the groove depth of the outer inclined groove located on the outer side is shallower by about 0.5 to 1 mm than the groove depth of the inner inclined groove located on the inner side. It is possible to make the wear state uniform at the time of disposal, and air for passenger cars that prevents or suppresses the uneven wear (non-uniform wear) phenomenon that the tread rubber located on the inside wears out earlier than the outside when wearing the vehicle. Incoming radial tires can be obtained , and unnecessary weight can be eliminated by making the distance from the bottom of the inclined groove to the belt constant . In addition, as a result of the configuration described above, the rigidity of the block located on the outside increases, so that the steering performance is improved, and favorable results are obtained for a high-performance tire having an aspect ratio of 55% or less.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, passenger car tires of Examples 1 to 3 and a conventional passenger car tire according to the present invention will be described with reference to the drawings. The tire size is 245/45 ZR17.
[0010]
FIG. 1 is a schematic front view of a pneumatic radial tire according to a first embodiment of the present invention mounted on a passenger car. As shown in the figure, since it has a negative camber, it is attached in the form of an inward opening that slightly falls inside.
The tire of Example 1 was a bead core provided in a pair of left and right bead parts, and extended from the crown part to both bead parts via both side parts, wound around the bead core and moored to the bead part. A pneumatic radial tire for a passenger car comprising a carcass ply formed of a radial cord layer, a belt disposed radially outward of a crown portion of the carcass ply, and a tread disposed radially outward of the belt. .
A large number of inclined grooves extending in the circumferentially inclined direction are arranged at intervals in the circumferential direction on both sides of the tread of the tire of the first embodiment, and are outwardly inclined when the tire is mounted on the vehicle. The groove depth of the groove is 7.5 mm, the groove depth of the inner inclined groove located on the inner side is 8.0 mm, and the groove depth of the outer inclined groove is 0.5 mm shallower than the groove depth of the inner inclined groove. Yes.
The aspect ratio defined by the ratio of the tire cross-sectional height to the tire cross-sectional width is 45%.
[0011]
The tire of Example 2
Except that when the tire is mounted on a vehicle, the outer inclined groove located on the outside has a depth of 7.0 mm, and the outer inclined groove has a depth that is 1.0 mm shallower than the inner inclined groove. This is the same as the tire of Example 1 above.
[0012]
The tire of Example 3 is
The outer inclined groove is formed of a groove having a relatively shallow groove depth of 7.0 mm and a groove having a relatively deep groove depth of 7.5 mm, and Except that these relatively shallow grooves and deep grooves are alternately arranged in the circumferential direction, the tire is the same as the tire of Example 1 described above.
[0013]
Conventional tires are
The groove depth of the outer inclined groove located outside when the tire is mounted on the vehicle is 8.0 mm, the groove depth of the inner inclined groove located inside is 8.0 mm, and the groove depth of the outer inclined groove Is the same as the tire of Example 1 except that it is the same as the groove depth of the inner inclined groove.
[0014]
About the tires of Examples 1 to 3 according to the present invention and the tires of the conventional example described above, the vehicle is actually mounted on the skyline GT-R, and the groove depth of the outer inclined groove at the time of complete wear, so-called remaining groove depth. A comparative test was conducted.
[0015]
As a result of the comparative test, the remaining groove depth of the tire of the conventional example is 1.2 mm, the remaining groove depth of the tire of Example 1 is 0.7 mm, and the remaining groove depth of the tire of Example 2 is determined. The remaining groove depth of the tire of Example 3 was 0.7 mm and 0.2 mm.
[0016]
【The invention's effect】
From the above evaluation results, the pneumatic tires of the examples according to the present invention are prevented or suppressed from the phenomenon of uneven wear (non-uniform wear), in which the tread rubber located on the inner side wears faster than the outer side when the vehicle is mounted. I understand that.
[Brief description of the drawings]
FIG. 1 is a schematic front view of a tire mounted on a passenger car.

Claims (4)

It consists of a bead core provided in a pair of left and right bead parts, and a radial cord layer that extends from the crown part to both bead parts through both side parts, wound around the bead core and moored to the bead part. A pneumatic radial tire comprising: a carcass ply; a belt disposed radially outward of the crown of the carcass ply; and a tread disposed radially outward of the belt. A large number of inclined grooves extending in the circumferentially inclined direction are arranged on both sides at intervals in the circumferential direction, and (2) the groove depth of the outer inclined groove located outside when the tire is mounted on the vehicle. but rather 0.5 to about 1mm shallow than the groove depth of the inner slant grooves located inside, (3) pneumatic Raj a distance from the groove bottom of the inclined groove to the belt is characterized in that it is a constant Le tire.   The pneumatic radial tire according to claim 1, wherein an aspect ratio defined by a ratio of a tire cross-sectional height to a tire cross-sectional width is 55% or less.   The pneumatic radial tire according to claim 1 or 2, wherein the outer inclined groove is formed of a groove having a relatively shallow groove depth and a deep groove. The pneumatic radial tire according to claim 3, wherein grooves having relatively shallow grooves and deep grooves forming the outer inclined grooves are alternately arranged in the circumferential direction.

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