JP3405668B2 - Abnormal wear prevention tire - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an abnormal wear preventing tire capable of effectively suppressing 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 tread portion of a tire to ensure wet running performance, for example, as shown in FIG. The tread pattern of the block type or the like in which the horizontal groove y that cuts the water film is crossed with respect to the vertical groove m of is often used. The horizontal groove y reduces the hitting sound at the time of grounding, the pumping sound, etc. 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, in a high performance flat radial tire having a reduced flatness ratio and improved tire rigidity, structural durability, etc., the flat width is increased and the ground contact pressure is reduced due to the flatness. High drainage performance is required on the equator side. Therefore, in this type of tire, it has been proposed to reduce the inclination angle θ of the lateral groove y to 45 degrees or less in the vicinity of the tire equator and bring the lateral groove closer to the running water line to enhance drainage performance on the tire equator side.

[0004]

However, when the inclination angle θ is reduced to 45 degrees or less, an acute angle between the lateral groove y and the vertical groove m in the block-shaped land portion B formed between the lateral grooves y. The rigidity of the side portion Ba is different from that of another obtuse side portion B, for example.
There is a problem that abnormal wear such as so-called heel and toe wear occurs such that the rigidity is significantly reduced as compared with b and the progress of wear at the acute angle side portion Ba is greatly delayed. In order to suppress abnormal wear, when the lateral groove y is terminated at a position apart from the vertical groove m, conduction between the lateral groove y and the vertical groove m is blocked, and it becomes difficult to obtain the necessary drainage property.

In view of this, the present invention is based on the provision of a tie bar that joins the lateral groove wall surfaces on both sides with a predetermined length and height in the vicinity of the intersection where the vertical groove and the lateral groove intersect at an acute angle. The purpose of the present invention is to provide an abnormal wear prevention tire capable of suppressing abnormal wear based on the above-mentioned conditions without impairing drainage performance.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention is applied to a vertical groove extending in a tire circumferential direction on a tread surface and a vertical groove wall surface of the vertical groove. with a lateral groove angle includes an acute inclined portion opening at a and the longitudinal grooves of the lateral groove walls extending at an 5-45 ° acute angle is formed, the sharp slope portion of the transverse groove, and said lateral groove wall surface the in the vicinity of the cross section and the longitudinal groove walls intersect, this
And raised from the groove bottom of the acute inclined portion provided tie bars extending in the longitudinal direction of the acute inclined portion with splicing between both sides of the lateral groove walls, projecting height d from the groove bottom of the tie bar, the lateral groove depth The tie bar length L of 0.3 to 0.8 times D and along the acute angled slope portion of the tie bar is the length L0 of the acute angled slope portion.
It is characterized by being 0.1 to 0.5 times.

It is preferable that the lateral groove extends from a vertical groove passing near the tire equator to a tread end, and the vertical groove is preferably formed in a straight line.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION 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 tire 1) is a flat radial tire for passenger cars in this example, and extends from a tread portion 2 to a side wall portion 3 around a bead core 5 of a bead portion 4. The carcass 6 is folded back and locked, and the belt layer 7 is provided outside the carcass 6 in the radial direction and inside the tread portion 2.

For the carcass 6, for example, an organic fiber cord made of polyester or the like is used in the range of 70 to 9 with respect to the tire equator C.
It is formed from one or more carcass plies arranged at a cord angle of 0 °, in this example, a carcass ply having a cord angle of 90 °.

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

As shown in FIG. 2, a vertical groove 10 extending in the tire circumferential direction is formed on the tread surface 2S of the tread portion 2.
And a lateral groove 11 opening at the vertical groove 10 is formed.

The vertical groove 10 is, in this example, the tire equator C.
A pair of vertical grooves 1 extending linearly in the vicinity of and on both sides of
0A and a central vertical groove 10B extending on the tire equator C through the vertical grooves 10A on this side.
The groove width Wg1 of 0B is set to 2 to the groove width Wg2 of the vertical groove 10A on the side.
The width is about 8 times wider.

Here, the "vicinity of the tire equator C" means an area range Y which is separated from the tire equator C by a distance equal to or less than 0.20 times the tire ground contact width TW, and the longitudinal groove 1 on the side.
0A is formed by positioning the center of the groove within this area range Y. Further, the "tire contact width TW" means the tread when the tire 1 is assembled on a standard rim specified by JATMA and the maximum load capacity is loaded by an air pressure corresponding to the maximum load capacity specified by JATMA. Surface 2S
Means the width in the tire axial direction of the ground contact area where the ground contacts.

Further, the lateral groove 11 is provided with an acute-angled inclined portion 12 that opens at the vertical groove 10A on the side, and in this example, a gently-inclined portion 13 that is continuous with the acute-angled inclined portion 12 and that opens at the tread end TE. , From the vertical groove 10A on the side to the tread end TE
Extend continuously.

The acute-angled sloped portion 12 of the lateral groove 11 is
Angle α formed with respect to the vertical groove wall surface Qa of the vertical groove 10A on the side
Is an area portion having a lateral groove wall surface Ra having an acute angle of 5 to 45 °, and in the present example, the acute angle slanted portion 12 has a substantially linear shape with the angle α being less than 25 °, for example, 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
It is formed of a substantially straight outer angled slope portion 12B of 0 °.

The inner and outer acute-angled inclined portions 12A, 12B
Has a groove width Wy substantially equal to each other in this example, and is 0.3 to 0.40 times the tire ground 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-angled inclined portion 12 may be formed in the shape of one straight groove in addition to the bent groove as in the present embodiment, and is further separated from the vertical groove wall surface Qa as shown in FIG. It can also be formed in a curved shape that is curved and extends to the side where it is formed. At this time, an area portion having the lateral groove wall surface Ra in which the angle α formed by the tangent line T of the lateral groove wall surface Ra and the vertical groove wall surface Qa is in the range of 5 to 45 degrees is referred to as an acute angle inclined portion 12. Also, the vertical groove 10 on the side
When A is a zigzag groove, an acute-angled slanted portion 12 is formed in an area portion where the angle α formed by the lateral groove wall surface Ra or the tangent line T of the lateral groove wall surface Ra with respect to the centerline of the zigzag groove, that is, the circumferential line is in the range of 5 to 45 degrees. Call it.

The gently inclined portion 13 is an area portion having a lateral groove wall surface R in which the angle α formed by the lateral groove wall surface R or its tangent line T with respect to the vertical groove wall surface Qa is larger than 45 degrees, and in this example, The angle α, which is continuous with the acute-angled inclined portion 12 at the bending point,
Has a linear shape of about 70 °, and is formed wider than the acute angle inclined portion 12.

Between the lateral grooves 11, 11, there is provided a lug groove which is open at the tread end TE and which has substantially the same shape as the gentle slope 13.

As described above, the horizontal groove 11 has the acute-angled inclined portion 12 and gradually decreases the angle α from the tread end TE toward the vertical groove 10A on the side, so that high drainage performance is required. On the tire equator side, the acute-angled inclined portion 12 has a function close to that of the vertical groove 10 and allows water to be discharged to the outside of the ground contact surface through a shorter locus to sufficiently enhance the drainage effect. Further, since the acute-angled inclined portion 12 reduces hitting sound, pumping sound, etc. at the time of contact with the ground, excellent low noise performance is also exhibited.

In the present application, as shown enlarged in FIG. 3, a tie bar 15 is formed in the acute-angled inclined portion 12 near the intersection 14 where the lateral groove wall surface Ra and the vertical groove wall surface Qa intersect.

The tie bar 15 is a shallow bottom portion protruding from the groove bottom of the lateral groove 11, and by connecting between the lateral groove wall surfaces Ra and Rb on both sides of the acute angle inclined portion 12, the vertical groove 10A and the acute angle inclined portion 12 are connected. Abnormal wear is suppressed by increasing the rigidity of the acute-angled side portion Ba of the block-shaped land portion B formed between the portions and reducing the difference in rigidity with other portions.

The tie bar 15 extends in the length 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 0.
1 to 0.5 times, and the projection height d (shown in FIG. 4) of the tie bar 15 from the groove bottom is set to 0.3 to 0.8 times the groove depth D of the front lateral groove 11. There is.

Here, the tie bar length L is defined by the length between the inner end E1 and the outer end E2 of the tie bar 15 along the center line N of the acute angled slope portion 12. In addition, in this example, the inner end E1 and the outer end E2 end substantially at right angles to the center line N, but as shown in FIG. 6, the inner end E1 and the outer end E2.
May be terminated obliquely, and 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 called the tie bar length L.

The length L0 of the acute-angled inclined portion is equal to that of the acute-angled inclined portion 1
The length 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, which is the length along the center line N between the inner and outer ends of 2. Is required as.

The diver length L is equal to
2 less than 0.1 times the length L0, and the protrusion height d
However, when the depth D of the lateral groove is less than 0.3 times, the effect of improving the rigidity of the acute-angled side portion Ba becomes insufficient, and abnormal wear suppression cannot be achieved. On the contrary, when the tie bar length L is greater than 0.5 times the length L0 and the protruding height d is greater than 0.8 times the lateral groove depth D, the drainage property is remarkable. It is difficult to maintain excellent wet performance, such as deterioration. 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.

Further, in the present embodiment, the intersection 14 has a cutout portion 16 with the top portion removed so as to prevent rubber filling failure and rubber chipping at the sharp top portion, and the inner end E1 of the tie bar is cut off. The distance K in the lengthwise direction from the cutout portion 16 can be made as small as possible within the range of 3.0 times or less the groove width Wy of the acute angle inclined portion 12,
It is preferable in terms of suppressing abnormal wear. The cut-off portion 16
If there is not, the distance of the inner end E1 of the tie bar from the intersection 14 is set to 3.0 times or less the groove width and as small as possible.

In the present application, the vertical grooves 10A, 10B,
The groove width and groove depth of the lateral groove 11 are not particularly limited, but the same range as in the case of a general radial tire for passenger cars can be used. For example, the groove depth is 5.0 to 9.0 m, respectively.
The range is preferably from 1.5 to 15.
The range of 0 mm is preferable. Further, by making the vertical grooves 10A and 10A close to each other, the vertical groove 10B can be eliminated or the vertical groove 1
It can be changed to various modes such that it can be formed by one vertical groove in which 0A, 10A and 10B are combined.

Further, such a tread pattern can exert a remarkable effect particularly 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 of FIG. 1 was prototyped based on the specifications of 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 trial tire was measured, and the measurement result was obtained. The results are compared and shown in Table 1.

Abrasion energy test: rim (6JJ ×
15), using a test tire with a rim assembled by air pressure (196 kPa) and a load (4.9 kN) loaded, slip angle on the road surface such as the surface of the rotating drum on which the in-contact surface stress measurement sensor and the slip amount measurement sensor are attached. (0 °), camber angle (0 °), speed (km / h), and the surface of each of the portions Ba and Bb when the acute angle side portion Ba and the obtuse angle side portion Bb pass each sensor. The internal stress and the slip amount were measured, and the wear energy was calculated as: wear energy = Σ {(in-plane stress) × (slip amount)}. In this example, a wear energy measuring device in which the in-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 which the range is 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 is 5 to 45 °
The wear energy difference rises to 17.01 J / m ² and induces abnormal wear. However, in Example 1 in which the tie bar was formed in the same pattern as in Comparative Example 1, the energy difference was up to 1.65 J / m ^2. It can be confirmed that it is reduced and abnormal wear is effectively suppressed.

[0035]

Since the present invention is constructed as described above,
Even when a lateral groove having an acute angled slope 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 drawings]

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

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

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

FIG. 4 is a sectional view thereof.

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

FIG. 6 is a partial plan view showing another example of the 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 lateral groove 12 acute angle slope 14 intersection 15 Thai bar Qa vertical groove wall surface Ra, Rb lateral groove wall surface α angle

Claims (3)

(57) [Claims] 1. A tread surface having a vertical 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 vertical groove wall surface. together with the transverse grooves, including the acute inclined portion which opening is formed, the sharp slope portion of the transverse groove, and in the vicinity of the intersections of said lateral grooves wall and the longitudinal groove wall intersects, of the acute inclined portion
The tie bars extending in the longitudinal direction of the acute <br/> angle inclined portions with and raised from the groove bottom succeed between both sides of the lateral groove walls provided, projecting height d from the groove bottom of the tie bar, the depth of the lateral grooves D
0.3 to 0.8 times the length of the tie bar along the acute-angled slope of the tie bar is 0.
An abnormal wear prevention tire characterized by being 1 to 0.5 times. 2. The abnormal wear preventing tire according to claim 1, wherein the lateral groove extends from a vertical groove passing near the tire equator to a tread end. 3. The intersection is cut off with its top removed.
An inner end E1 of the tie bar on the side of the intersection.
The distance K in the length direction from the cut-off portion
Characterized by the range of 3.0 times or less of the groove width Wy of the oblique part
The abnormal wear preventing tire according to claim 1.