JP2011189757A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire improved in controllability, stability, and steerability, while suppressing an increase in weight of the tire and deterioration in ride comfort performance. <P>SOLUTION: In this pneumatic tire, a belt 3 is arranged at the tire radial direction outside of a crown part of a carcass 2 toroidally stretching between a pair of bead parts, a tread 4 is arranged at the tire radial direction outside of the belt 3, and a side reinforcing layer 6 is provided at the tire width direction outside of the carcass 2. The side reinforcing layer 6 includes a projection part 6b continuous in a projecting-shaped tire peripheral direction at the tire width direction outside. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire with improved steering stability and steering performance while suppressing an increase in weight of the tire and a decrease in riding comfort performance.

  Some conventional pneumatic tires have improved in-plane rotational rigidity by disposing a side reinforcing layer made of a sheet having a certain thickness on a side portion of the tire as in Patent Document 1, for example. Here, “in-plane rotational rigidity” refers to the rigidity against the rotational force of the tire as shown in FIG. 1 (a), and “out-of-plane torsional rigidity” described later is as shown in FIG. 1 (b). Further, it refers to the rigidity against torsion around the axis L2 orthogonal to the tire rotation axis L1.

JP-A-10-250321

Since the above tires have increased rigidity in the circumferential direction of the tire, in-plane rotational rigidity is improved and steering stability is improved, but a great improvement in rigidity against torsion during steering cannot be achieved. There was no room for improvement in terms of steering, and no significant improvement in rigidity was expected.
In order to improve the out-of-plane torsional rigidity, for example, a method of providing a wide high elastic rubber or the like is conceivable. However, this method increases the vertical spring constant, which may cause a decrease in ride comfort. there were. Furthermore, the provision of highly elastic rubber increases the weight of the tire, resulting in an increase in rolling resistance.

  An object of the present invention is to provide a pneumatic tire that improves both steering stability and steering performance while suppressing an increase in tire weight and a decrease in riding comfort performance.

The inventors have made extensive studies to solve the above problems.
As a result, by providing protrusions that are continuous in the tire circumferential direction on the side reinforcing layer of the highly elastic sheet, the rigidity is improved not only in the in-plane direction but also in the out-of-plane direction, and the steering stability and steering performance are improved. The present inventors have obtained new knowledge that it is possible to limit the increase in weight at that time, and that the decrease in ride comfort can be minimized.

The gist configuration of the pneumatic tire according to the present invention is as follows.
(1) A belt on the outer side in the tire radial direction of the crown portion of the carcass straddling a toroidal shape between the pair of bead portions, and a tread on the outer side in the tire radial direction of the belt, and on the outer side in the tire width direction of the carcass, In a pneumatic tire having a reinforcing layer,
The pneumatic tire is characterized in that the side reinforcing layer has a protrusion that is convex outward in the tire width direction and continuous in the tire circumferential direction.

  (2) The pneumatic tire according to (1), wherein the protrusion is provided in a tire maximum width portion.

  (3) The pneumatic tire according to (1) or (2), wherein the protrusion is provided at an end of the side reinforcing layer.

  INDUSTRIAL APPLICABILITY The present invention can provide a pneumatic tire with improved steering stability and steering performance without deteriorating the tire weight and riding comfort performance by devising the structure and shape of the side reinforcing layer of the high elastic sheet. .

It is a figure for demonstrating in-plane rotational rigidity and out-of-plane torsional rigidity. It is sectional drawing of the pneumatic tire of one Embodiment concerning this invention. It is sectional drawing of the side reinforcement layer of this invention. It is a figure explaining the dimension of a side reinforcement layer main-body part and a projection part.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2 is a cross-sectional view of a pneumatic tire (hereinafter referred to as “tire”) according to an embodiment of the present invention.

FIG. 2 shows only the half of the tire of the present invention with the equator plane O of the tire as a boundary. The tire includes a carcass 2 extending in a toroidal shape between a pair of bead cores 1, a belt 3 composed of a plurality of layers arranged on the outer side in the tire radial direction of the crown portion of the carcass 2, and an outer side in the tire radial direction of the belt 3 The tread 4 is the basic structure.
The side portion 5 has a side reinforcing layer 6 on the outer side in the tire width direction of the folded portion of the carcass 2.
An inner liner 7 is disposed along the carcass 2 on the inner surface of the tire.

FIG. 3 is a cross-sectional view of the side reinforcing layer 6 used in the present invention.
As shown in FIGS. 3 (a) and 3 (b), the main body portion 6a of the side reinforcing layer 6 has a protruding portion 6b continuous in the tire circumferential direction on the outer side in the tire width direction.
That is, in the tire of the present invention, it is important to dispose a side reinforcing layer having a protruding portion continuous in the tire circumferential direction that is convex outward in the tire width direction on the outer side in the tire width direction of the carcass.
Thereby, since the side reinforcing layer 6 is first disposed on the outer side in the tire width direction of the carcass, rigidity in the tire circumferential direction is increased, in-plane rotational rigidity is increased, and steering stability is improved.
In addition, since the side reinforcing layer 6 has the protruding portion 6b, the protrusion that is continuous in the circumferential direction acts to form a ring-shaped reinforcing material, and as a result, the out-of-plane torsional rigidity is increased. As a result, the rigidity is improved and the steering performance is improved.
Furthermore, since the protruding portion 6b is provided only on a part of the side reinforcing layer 6, the increase in weight and spring coefficient can be suppressed to a slight one, and therefore, the increase in rolling resistance is suppressed, and the riding comfort performance. Can be prevented.

As shown in FIG. 2 (a), the protrusion 6b is preferably provided at the tire maximum width portion of the side portion of the tire.
This is because the tire's maximum width portion is the portion where bending deformation is greatest during steering, and by providing a protrusion here, the rigidity against torsion during steering can be increased efficiently, and as a result, steering performance is further improved. It is because it can be made.
Here, the “maximum tire width” means the maximum tire width when it is mounted on the applicable rim at the applicable size specified in the 2005 YEAR BOOK issued by JATMA and filled with the specified internal pressure. It means a lot.

Further, the protrusion 6b can be provided at the end of the side reinforcing layer 6, as shown in FIG. 2 (b).
This is because, by thickening the end portion of the side reinforcing layer 6, it is possible to suppress the end portion peeling between the side rubber 5 and the reinforcing layer 6.

Here, the side reinforcing layer 6 having the protrusion 6b is preferably disposed at a position of 15% to 65% of the tire cross-section height from the rim base line side.
If the side reinforcing layer 6 is disposed at a position exceeding 65% (side area in the tire radial direction of the side part) or less than 15% (side area in the tire radial direction of the side part), rigidity in the tire radial direction is also increased. This is because the problem of increasing road noise occurs. On the other hand, if the range is 15% to 65%, only the rigidity in the tire circumferential direction is increased, and such a problem does not occur.
Moreover, if the side reinforcing layer is provided also in the tire radial direction outer side region and the tire radial direction inner side region of the side part, the tire weight increases.
This is because the in-plane rotational rigidity and the out-of-plane torsional rigidity cannot be sufficiently improved only by providing in a range narrower than this range.

Moreover, it is preferable that the hardness of the rubber used for the side reinforcing layer 6 including the protruding portion 6b is 90 to 100.
If the hardness is less than 90, the effect of improving the rigidity cannot be sufficiently obtained.On the other hand, if it exceeds 100, the rigidity becomes too high, so that the ride comfort is deteriorated. This is because the resulting separation is likely to occur.

Furthermore, referring to FIG. 4, the thickness t in the width direction of the main body portion 6a of the reinforcing layer is not particularly limited, but is preferably 0.5 mm to 1.0 mm.
This is because if the thickness is less than 0.5 mm, the rigidity of the side portion is not sufficiently improved, and if it is greater than 1.0 mm, the weight increases.

Also, as shown in FIG. 4, when the tire radial direction length of the side reinforcing layer 6 is A, and the tire radial direction length of the protrusion 6b is a,
0.05A ≦ a ≦ 0.5A
It is preferable to satisfy.

  Further, the thickness T in the tire width direction of the protrusion 6b is preferably 1.5 to 2.5 times the thickness t in the tire width direction of the main body 6a of the side reinforcing layer 6.

  In addition, if the cross-sectional shape of the protrusion 6b in the tire width direction is a shape protruding outward in the tire width direction, in addition to the round shape shown in FIGS. 2 (a) and 2 (b), a quadrangular shape, a triangular shape, a semicircle It may be a shape.

Next, in order to confirm that the tire of the present invention is excellent in steering stability and steering performance, a test for evaluating the tabletop characteristics and a test run by a driver were performed.
Here, as an example of the invention, a tire in which a side reinforcing layer having protrusions continuous in the tire circumferential direction having a shape convex outward in the tire width direction as shown in FIG. did.
As a conventional example, a tire provided with a sheet-like side reinforcing layer on the outer side in the tire width direction of the carcass was prepared.

  In order to evaluate the stand characteristics, steering stability, steering performance, and riding comfort of the tire, each tire of tire size P205 / 55R16 is mounted on a rim of rim size 6.5J-16, the internal pressure is 250 kPa, and the tire is 5.0 kN The following test was conducted.

As shown in Table 1, it can be seen that the inventive tire has a smaller torsion spring constant and superior maneuverability than the conventional tire.
Further, it can be seen that the weight, handling stability, and riding comfort are the same as those of the conventional tire.

1 Bead core
2 Carcass
3 belt
4 tread
5 Side
6 Side reinforcement layer
6a Side reinforcement layer body
6b Projection
7 Inner liner
L1 tire rotation axis
L2 Axis perpendicular to tire rotation axis
O Tire equator

Claims (3)

A belt and a tread on the outer side in the tire radial direction of the belt are arranged on the outer side in the tire radial direction of the crown of the carcass straddling the toroidal shape between the pair of beads, and a side reinforcing layer is provided on the outer side in the tire width direction of the carcass. In a pneumatic tire having
The pneumatic tire is characterized in that the side reinforcing layer has a protrusion that is convex outward in the tire width direction and continuous in the tire circumferential direction.   2. The pneumatic tire according to claim 1, wherein the protrusion is provided in a tire maximum width portion.   3. The pneumatic tire according to claim 1, wherein the protrusion is provided at an end of the side reinforcing layer.

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