JPH11105510A - Abnormal abrasion protective tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly maintain rigidity of blocks of flat parts, and to effectively restrict abnormal abrasion without damaging draining performance. SOLUTION: This tire is provided with a lateral groove including an acute- angled inclination part having a lateral groove wall surface Ra which crosses a vertical groove wall surface Qa of a vertical groove extended in a tire circumferential direction at an angle α of 5-45 deg.. Close to a crossing part 14 and at the acute-angled inclination part, a tie bar 15 extended in a length direction connecting the lateral groove wall surfaces Ra, Rb on both sides of the acute- angled inclination is provided. A protruded height (d) of the tie bar 15 is set to be 0.3-0.8 times a lateral groove depth D, and a length L of the tie bar 15 is set to be 0.1-0.5 times a length L0 of the acute-angled inclination part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormal wear preventing tire which can effectively suppress abnormal wear while exhibiting excellent wet performance.

[0002]

2. Description of the Related Art Generally, in order to ensure wet running performance by draining a water film between a road surface and a road surface on a tread portion of a tire, for example, as shown in FIG. A tread pattern such as a block type in which a horizontal groove y for cutting a water film intersects with the vertical groove m is often used, and the horizontal groove y is used in order to reduce a hitting sound at the time of ground contact, a pumping sound, and the like. Usually, they are arranged with an inclination angle θ of about 60 to 90 degrees with respect to the circumferential direction.

On the other hand, high performance flat radial tires having a reduced flatness and improved tire stiffness and structural durability have been developed especially because of the increase in the contact width and the decrease in the contact pressure due to the flattening. High drainage performance is required on the equator side. Therefore, in this type of tire, it has been proposed that the inclination angle θ of the lateral groove y is reduced to 45 degrees or less near the tire equator, and the lateral groove is made closer to the running water line to enhance drainage performance on the tire equator side.

[0004]

However, when the inclination angle .theta. Is reduced to 45 degrees or less, the acute angle between the horizontal groove y and the vertical groove m in the block-shaped land portion B formed between the horizontal grooves y. The rigidity of the side part Ba is different from that of the other obtuse side part B, for example.
There is a problem in that abnormal wear such as so-called heel & toe wear occurs, for example, significantly lower than the rigidity of b, and the wear progress in the acute angle side portion Ba is greatly delayed. When the horizontal groove y is terminated at a position away from the vertical groove m to suppress abnormal wear, conduction between the horizontal groove y and the vertical groove m is prevented, so that it is difficult to obtain necessary drainage.

Accordingly, the present invention is based on the provision of a tie bar having a predetermined length and height at the intersection of the vertical groove and the horizontal groove at an acute angle, which connects the wall surfaces of the horizontal grooves on both sides. It is an object of the present invention to provide an abnormal wear preventing tire that can suppress abnormal wear based on the tire without damaging drainage.

[0006]

In order to achieve the above-mentioned object, the present invention relates to a vertical groove extending in the tire circumferential direction on a tread surface, and an angle between the vertical groove wall and the vertical groove wall is 5 to 45.
A transverse groove having a transverse groove wall surface extending at an acute angle of 鋭 and a transverse groove including an acute angle inclined portion opened by a vertical groove is formed, and an intersection of the acute angle inclined portion where the horizontal groove wall surface and the vertical groove wall surface intersect. Is provided with a tie bar that joins the lateral groove wall surfaces on both sides of the acute angled inclined portion and extends in the length direction of the acute angled inclined portion.
The tie bar length L along the acute angled portion of the tie bar is 3 to 0.8 times, and the length L0 of the acute angled inclined portion is 0.1 to 0.1.
It is characterized by 0.5 times.

[0007] The lateral groove preferably extends from a vertical groove passing near the tire equator to the tread edge, and the vertical groove is preferably formed in a straight line.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, an abnormal wear prevention tire 1 (hereinafter referred to as a tire 1) is a flat radial tire for a passenger car in this example, and extends around a bead core 5 of a bead portion 4 from a tread portion 2 to a sidewall portion 3. The carcass 6 includes a carcass 6 that is folded and locked, and a belt layer 7 that is disposed radially outside the carcass 6 and inside the tread portion 2.

The carcass 6 is made of an organic fiber cord made of, for example, polyester or the like.
It is formed from one or more carcass plies arranged at a cord angle of 0 °, in this example, one carcass ply having a cord angle of 90 °.

The belt layer 7 is formed by applying a highly elastic belt cord such as a steel cord to the tire equator C by one.
Two or more belt plies 7A, 7B arranged at a cord angle of 0 ° to 30 °, in this example, at a cord angle of 24 °.
The belt cords are stacked in different directions so as to cross each other between the plies. Further, on the outer side of the belt layer 7, a reinforcing layer 9 that covers at least the outer end portion of the belt layer 7 and suppresses lifting due to high-speed running is formed by spirally winding an organic fiber cord such as nylon.

As shown in FIG. 2, the tread surface 2S of the tread portion 2 has a longitudinal groove 10 extending in the tire circumferential direction.
Then, a tread pattern including a horizontal groove 11 opened by the vertical groove 10 is formed.

In the present embodiment, the longitudinal groove 10 is provided with a tire equator C.
A pair of longitudinal grooves 1 extending linearly in the vicinity of and on both sides thereof
0A and a central longitudinal groove 10B extending on the tire equator C passing between the longitudinal grooves 10A on this side.
0B of the groove width Wg2 of the side vertical groove 10A is 2 to 2 of the groove width Wg2 of the side vertical groove 10A.
It is formed about eight times as wide.

Here, the term "near the tire equator C" means an area range Y separated from the tire equator C by a distance equal to or less than 0.20 times the tire contact width TW.
0A is formed such that the center of the groove is located within this area range Y. The "tire contact width TW" is defined as the rim of the tire 1 mounted on a standard rim specified by JATMA, and the tread when the tire 1 is loaded with the maximum load capacity at an air pressure corresponding to the maximum load capacity specified by JATMA. Surface 2S
Means the width in the tire axial direction of the contact surface area where the contact is made.

Further, the lateral groove 11 has an acute-angled inclined portion 12 opened by the vertical groove 10A on the side, and in this example, a gentle inclined portion 13 connected to the outside of the acute-angled inclined portion 12 and opened at the tread end TE. , From the longitudinal groove 10A on the tread end TE
Extend continuously.

The acute angle inclined portion 12 is formed in the lateral groove 11
The angle α formed by the vertical groove wall 10a of the vertical groove 10A on the side.
Is a region portion having a lateral groove wall Ra forming an acute angle of 5 to 45 °, and in this example, the acute angle inclined portion 12 has an angle α of less than 25 °, for example, a substantially linear shape of about 20 °. The acute angled inclined portion 12A is connected to the acute angled inclined portion 12A at a bending point, and the angle α is 25 ° or more, for example, about 3 °.
0 ° and a substantially linear outer acute-angled inclined portion 12B.

The inner and outer acute-angled inclined portions 12A and 12B
Have a groove width Wy which is substantially equal to each other in this example, and is 0.3 to 0.40 times the tire contact width TW from the tire equator C,
For example, it extends to a position separated by a distance of 0.35 times.

The acute angle inclined portion 12 may be formed in a single linear groove in addition to the bent groove shape as in the present embodiment, and further, as shown in FIG. 5, is separated from the vertical groove wall surface Qa. It can also be formed in a curved shape that curves to the side to be bent. At this time, the region having the lateral groove wall Ra in which the angle α formed between the tangent line T of the lateral groove wall Ra and the vertical groove wall Qa is in the range of 5 to 45 degrees is referred to as an acute angle inclined portion 12. The vertical groove 10 on the side
When A is a zig-zag groove, the region where the angle α formed by the lateral groove wall surface Ra or the tangent T of the lateral groove wall surface Ra with respect to the center line of the zigzag, that is, the circumferential direction line is in the range of 5 to 45 degrees is formed by the acute angle inclined portion 12. Call it.

The gentle slope portion 13 is a region having a lateral groove wall surface R or an angle α formed by the tangent line T with respect to the vertical groove wall surface Qa is larger than 45 degrees. The angle α, which is connected to the acute angled slope 12 at a bending point.
Has a linear shape of approximately 70 °, and is formed wider than the acute-angled inclined portion 12.

A lug groove 17 which is open at the tread end TE and has substantially the same shape as the gentle inclined portion 13 is provided between the lateral grooves 11, 11.

As described above, since the lateral groove 11 has the acute angle inclined portion 12 and the angle α is decreased stepwise or continuously from the tread end TE toward the longitudinal groove 10A, high drainage performance is required. On the tire equator side, the acute angle inclined portion 12 has a function close to the vertical groove 10 and discharges water out of the ground contact surface through a shorter trajectory, so that the drainage effect can be sufficiently enhanced. In addition, the sharp angled inclined portion 12 reduces the impact sound, the pumping sound, and the like at the time of contact with the ground, so that excellent low noise performance is also exhibited.

In the present application, a tie bar 15 is formed near the intersection 14 where the horizontal groove wall surface Ra and the vertical groove wall surface Qa intersect with each other at the acute angle inclined portion 12 as shown in FIG.

The tie bar 15 is a shallow portion that protrudes from the bottom of the lateral groove 11 and connects between the lateral groove wall surfaces Ra and Rb on both sides of the acute angle inclined portion 12 so that the vertical groove 10A and the acute angle inclined portion 12 are connected to each other. The rigidity of the acute-angle side portion Ba of the block-shaped land portion B formed between them is increased, and the difference in rigidity with other portions is reduced, thereby suppressing abnormal wear.

The tie bar 15 extends in the longitudinal direction of the acute-angled inclined portion 12, and the tie bar length L along the acute-angled inclined portion 12 of the tie bar 15 is set to 0.
1 to 0.5 times, and the projecting height d (shown in FIG. 4) of the tie bar 15 from the groove bottom is set to a range of 0.3 to 0.8 times the groove depth D of the front lateral groove 11. I have.

Here, the tie bar length L is defined as a length between the inner end E1 and the outer end E2 of the tie bar 15 along the center line N of the acutely inclined portion 12. In this example, the inner end E1 and the outer end E2 terminate substantially at right angles to the center line N. However, as shown in FIG.
May be terminated diagonally. At this time, the length along the center line N between the points where the inner end E1 and the outer end E2 intersect the center line N is referred to as a tie bar length L.

The length L0 of the acute angled inclined portion is
2 is the length along the center line N between the inner end and the outer end, and in this example, the sum L0A + LOB of the length L0A of the inner acute-angled inclined portion 12A and the length L0B of the outer acute-angled inclined portion 12B. Is required.

It should be noted that the diver length L is equal to the acute angled inclined portion 1.
2 is less than 0.1 times the length L0, and the protrusion height d
However, when the lateral groove depth D is less than 0.3 times, the effect of improving the rigidity of the acute angle side portion Ba becomes insufficient, and the suppression of abnormal wear is not achieved. Conversely, when the tie bar length L is larger than 0.5 times the length L0 and when the protrusion height d is larger than 0.8 times the lateral groove depth D, the drainage is remarkable. For example, it is difficult to maintain excellent wet performance, for example, a decrease is caused. Therefore,
The ratio L / LO is in the range of 0.2 to 0.4, and the ratio d / D is
The range of 0.45 to 0.65 is more preferable.

In this embodiment, the crossing portion 14 has a cut-out portion 16 in which the apex is removed so as to prevent poor rubber filling at the sharp apex and chipping of the rubber. The distance K in the longitudinal direction from the cutout portion 16 is made as small as possible within a range not more than 3.0 times the groove width Wy of the acute-angled inclined portion 12,
It is preferable in terms of suppressing abnormal wear. Note that the cut-out portion 16
When there is no tie bar, the distance from the intersection 14 of the tie bar inner end E1 is set to be as small as 3.0 times or less the groove width.

In the present application, the longitudinal grooves 10A, 10B,
The groove width and groove depth of the lateral groove 11 are not particularly limited, but the same range as that of a general tire for a passenger car can be used. For example, the groove depth is 5.0 to 9.0 m, respectively.
m is preferable, and the groove width is 1.5 to 15.
A range of 0 mm is preferred. Further, by bringing the vertical grooves 10A and 10A closer to each other, the vertical groove 10B can be eliminated, or the vertical groove 1A can be removed.
It can be changed to various modes, for example, it can be formed by one vertical groove combining 0A, 10A, and 10B.

Such a tread pattern is particularly effective in a high-performance tire having an aspect ratio of 60% or less.

[0030]

[Example] The tire size is 195 / 65R15,
A pneumatic tire having the basic configuration shown in FIG. 1 was prototyped based on the specifications in Table 1, and the wear energy of the acute angle side portion Ba and the obtuse angle side portion Bb in the block-shaped land portion B of each test tire was measured. Are shown in Table 1.

Abrasion energy test: rim (6JJ ×
15) Using a test tire with a rim assembled under air pressure (196 kPa) and a load (4.9 kN), the slip angle on a road surface such as the surface of a rotating drum to which a sensor for measuring in-plane stress and a sensor for measuring the amount of slip were mounted. (0 °), traveling at a camber angle (0 °), and speed (km / h), and the surfaces of the portions Ba and Bb when the acute-angle portion Ba and the obtuse-angle portion Bb pass through each sensor. The internal stress and the slip amount were measured, and the wear energy was calculated as wear energy = {(in-plane stress) × (slip amount)}. In this example, a wear energy measuring device in which the above-mentioned in-ground-plane stress measuring sensor and the slip amount measuring sensor were integrated was used.

[0032]

[Table 1]

As shown in Table 1, the inclination angle θ is 60 to 9
In the conventional tires 1 and 2 in the range of 0 °, the rigidity of the block-shaped land portion B is relatively uniform, and the difference between the wear energy of the acute angle side portion Ba and the wear energy of the obtuse angle side portion Bb is 5.78 J /. m ² and a small consisting for abnormal wear and 6.41J / m ² does not occur.

On the other hand, Comparative Example 1 in which the angle α was 5 to 45 °
In this example, the wear energy difference rises to 17.01 J / m ² and induces abnormal wear. In Example 1 in which the tie bar was formed in the same pattern as in Comparative Example 1, the energy difference was 1.65 J / m ^2. It can be confirmed that the amount is reduced and abnormal wear is effectively suppressed.

[0035]

Since the present invention is configured as described above,
Even when a lateral groove having an acute-angled inclined portion is used, the rigidity of the block-shaped land portion can be kept uniform, and abnormal wear can be effectively suppressed without impairing drainage.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tire according to an embodiment of the present invention.

FIG. 2 is a developed view showing the tread pattern.

FIG. 3 is an enlarged plan view showing an acute angle inclined portion.

FIG. 4 is a sectional view thereof.

FIG. 5 is a plan view showing another example of the acute-angled inclined portion.

FIG. 6 is a partial plan view showing another example of a tie bar.

FIG. 7 is a development view showing an example of a tread pattern of a conventional tire.

[Explanation of symbols]

 2S tread surface 10, 10A, 10B vertical groove 11 horizontal groove 12 acute angled slope 14 intersection 15 tie bar Qa vertical groove wall surface Ra, Rb horizontal groove wall α angle

Claims (3)

[Claims] A tread surface has a longitudinal groove extending in the tire circumferential direction, and a lateral groove wall surface extending at an acute angle of 5 to 45 ° with respect to the longitudinal groove wall surface of the longitudinal groove. A horizontal groove including an acute-angled inclined portion that opens is formed, and near the intersection of the acute-angled inclined portion and the horizontal groove wall surface and the vertical groove wall surface, the lateral groove wall surfaces on both sides of the acute-angled inclined portion are spliced. A tie bar extending in the length direction of the tie bar, and the height d of the tie bar protruding from the groove bottom is 0.3 to 0.8 times the depth D of the lateral groove, and the tie bar extends along the acute angle inclined portion of the tie bar. The length L is 0.1 of the length L0 of the acute angle inclined portion.
An abnormal wear prevention tire characterized in that the thickness is 0.5 to 0.5 times. 2. The abnormal wear preventing tire according to claim 1, wherein said lateral groove extends from a vertical groove passing near the tire equator to a tread end. 3. An abnormal wear preventing tire according to claim 1, wherein said vertical groove extends linearly in the tire circumferential direction.