JPH092021A - High maneuverability pneumatic tire having directional slant block - Google Patents

Abstract

PURPOSE: To improve stability of operation on a wet road surface by arranging a part of a directional slant block so as to bite into a rib in the circumferential direction, forming the extreme end corner part bitten therein into a tapering acute angle shape, and gradually lowering the block height of the extreme end corner part following to biting-in so as to end at specific height. CONSTITUTION: The block center lines of directional slant blocks 2, 3 are extended so as to slant at a low angle θ1 (for example 25 degrees) against the circumferential direction in a tread inside territory, and the block center lines are extended at a high angle θ2 (for example 60 degrees) against the circumferential direction in a tread outside territory. One part of the directional slant block 3 is arranged so as to bite in a rib 1 in the circumferential direction without spoiling continuity in the circumferential direction of the rib 1, and the extreme end corner part bitten therein is formed into a tapering acute angle shape and the angle θ3 is 35 degrees for example. The block height of the extreme end corner part is gradually lowered following to biting-in, and ended at 0-20% height of the rib 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire for a passenger car, and more particularly to a pneumatic tire for a passenger car having a high exercise performance which emphasizes exercise performance capable of supporting sports driving.

[0002]

2. Description of the Related Art A typical conventional tread pattern of a pneumatic tire for a high-performance passenger car is shown in FIG. As shown in the figure, the conventional tire has several tires (four tires in the illustrated example,
The tread pattern is composed of circumferential grooves (generally about 2 to 8) and a large number of directional inclined grooves arranged at intervals in the circumferential direction. In the present specification, the “circumferential groove” means a groove continuously extending in the circumferential direction, the “circumferential rib” means a rib continuously extending in the circumferential direction, and the “directional inclined groove”. ”Is a groove that extends obliquely with respect to the circumferential direction, and when the tire rotates in the normal direction, the side of the groove that extends obliquely near the tire equatorial plane contacts the ground first, and the side far from the equatorial plane is It means a groove in which a so-called directional tread pattern is formed, in which the direction of rotation of the tire when it is mounted on the vehicle is designated so as to be grounded later, and the "directional tilt block" means the directional tilt groove. Formed by,
A block extending obliquely with respect to the circumferential direction, so that when the tire rotates in the normal direction, the side of the block extending obliquely near the tire equatorial plane comes into contact first, and the side farther from the equatorial plane comes into contact later. The block in which a so-called directional tread pattern is formed, in which the direction of rotation of the tire when it is mounted on the vehicle is designated.

In order to improve steering stability and hydroplaning characteristics on a wet road surface in the conventional tire as described above, the number of grooves and the groove width are increased to increase the negative ratio (area of the groove surface with respect to the area of the tread contact surface). It is effective to increase the ratio), and in particular, to increase the negative ratio of the directional tilted groove, which is a frequently adopted design method. However, in a pneumatic tire having a directional tread pattern excellent in wet performance designed by this method, uneven wear resistance performance and steering stability performance on dry road surface are deteriorated. On the contrary, when trying to secure the uneven wear resistance performance and the steering stability performance on the dry road surface with the conventional tire as described above, it was difficult to enhance the steering stability on the wet road surface and the hydro planing characteristics. .

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high athletic performance tire which emphasizes athletic performance capable of supporting sports running as well, and has reduced uneven wear resistance and steering stability on dry road surfaces. It is an object of the present invention to provide a novel tread pattern used for pneumatic tires for passenger cars, which has excellent steering stability on wet road surfaces and hydro-planing characteristics, without the need to do so.

[0005]

In order to achieve the above object, a pneumatic tire for passenger cars according to the present invention comprises at least one circumferential rib extending continuously in the circumferential direction and a circumferential rib extending from the circumferential rib. A pneumatic tire having a directional tread pattern, which comprises a plurality of directional tilt blocks that are inclined with respect to the direction and are provided at intervals in the circumferential direction, (1) A part is arranged so as to bite into the circumferential rib without impairing the circumferential continuity of the circumferential rib, and (2) a tip corner portion that bites into the circumferential rib of the directional tilt block. Is a tapered acute-angled shape, and (3) the block height of the tip corner portion that bites into at least the circumferential rib of the directional inclined block gradually decreases as it goes into the circumferential rib. Rib A pneumatic tire characterized by terminating at 0 to 20 percent of the.

In order to achieve the above-mentioned object, the angle of the tip corner portion of the directional tilted block which bites into the circumferential rib and forms a tapered acute angle shape is 20 to 90 degrees. It is preferably 30 to 70 degrees, and more preferably 30 degrees. Further, it is preferable that the directional inclined block bites into the central portion of the circumferential rib and terminates.

To achieve the above objects, the circumferential ribs are arranged in the pattern center to form a central circumferential rib, and the directional tilt blocks are arranged to the left and right of the central circumferential rib. It is preferable that the directional inclined blocks are arranged on the left and right sides of the central circumferential rib with a half pitch shift in the circumferential direction.

In order to achieve the above-mentioned object, the directional inclined block continuously extends from the left and right of the central circumferential rib to both ends of the tread, and the block center line of the directional inclined block is in the tread inner region. It is preferable to extend at a low angle of about 20 to 40 degrees with respect to the circumferential direction, and to extend at a high angle of about 60 to 70 degrees with respect to the circumferential direction in the tread outer region.

To achieve the above object, the circumferential ribs are disposed near the midpoints of the pattern center and the tread ends to form two intermediate circumferential ribs, and the directional tilt block comprises: A circumferential groove is formed between the intermediate circumferential rib and the directional inclined blocks arranged on the tread end side of the intermediate circumferential rib, which are arranged on the left and right of the central circumferential rib, or The directional inclined blocks are arranged on the left and right of the intermediate circumferential rib, and the directional inclined blocks arranged on the left and right of the central circumferential rib and the pattern center side of the intermediate circumferential rib. A circumferential groove is preferably formed between the directional tilt block and the directional tilt block.

[0010]

According to the pneumatic tire for passenger cars of the present invention, at least one circumferential rib continuously extending in the circumferential direction, and extending from the circumferential rib at an angle with respect to the circumferential direction and spaced apart in the circumferential direction. In a pneumatic tire having a directional tread pattern provided with a plurality of directional tilt blocks provided as described above, the tip corner portion that bites into the circumferential rib of the directional tilt block has a tapered acute angle shape. The ground resistance to the water film is reduced, and a tire having excellent drainage performance can be obtained. However, if the tip corner portion of the block is formed into a tapered acute-angled shape, the rigidity becomes low and uneven wear is likely to occur. In the pneumatic tire for passenger cars of the present invention, the block height of the tip corner portion of the directional inclined block is gradually lowered so as to end at 0 to 20% of the height of the circumferential rib, and at least the block height of the block is increased. Since the corners of the tip are chamfered, uneven wear is prevented or suppressed. Chamfering the tip corners of the block further improves drainage performance.
However, when the chamfer blocks are concentrated, the ground contact area is reduced and the tread rigidity is reduced, so that the wear resistance performance and the steering stability performance are deteriorated. Therefore, in the pneumatic tire for passenger cars of the present invention, a part of the directional inclination block is arranged so as to bite into the circumferential rib without impairing the circumferential continuity of the circumferential rib, and The block height of the tip corner portion of at least the circumferential rib of the flexible inclined block gradually decreases as it goes into the circumferential rib, and ends at 0 to 20% of the height of the circumferential rib. Thus, at least the corner of the tip of the block was chamfered.
This secures the ground contact area and tread rigidity, and prevents deterioration of wear resistance and steering stability. It should be noted that the wide portion of the tip corner portion of the block can ensure rigidity even if the chamfering amount is small, but the narrow portion of the block tip corner portion is deeply chamfered because the rigidity becomes insufficient when the chamfering amount is small.

In the pneumatic tire for passenger cars according to the present invention, the angle of the tip corner portion which is biting into the circumferential rib of the directional tilt block and forms a tapered acute angle is 20 to 9.
It is preferably 0 degrees, and more preferably 30 to 70 degrees. If the angle of the tip corner becomes smaller than the above value, the rigidity becomes too low, and if the chamfering is deep enough to compensate for it, the contact area will be insufficient, and conversely, if it becomes larger than the above value, the tapered acute angle shape will be formed. It becomes difficult to form and improve hydro-planing characteristics. Also,
In the pneumatic tire for passenger cars of the present invention, the directional inclined block bites into the central portion of the circumferential rib and terminates, so that the contact pressure of the circumferential rib is increased and a tire having excellent hydro-planing characteristics is obtained. Preferred for achieving the object of the present invention.

In the pneumatic tire for passenger cars of the present invention, the circumferential ribs are arranged in the pattern center to form the central circumferential rib, and the directional tilt blocks are arranged on the left and right of the central circumferential rib. More preferably, the directional tilt blocks are arranged on the left and right of the central circumferential rib with a half pitch shift in the circumferential direction. With such a configuration, the input during tire rolling is distributed to the left and right,
Tire noise is reduced.

In the pneumatic tire for passenger cars of the present invention, the directional tilt block continuously extends from the left and right of the central circumferential rib to both ends of the tread, and the block center line of the directional tilt block is circumferential in the tread inner region. Against 20
It is preferable to extend at a low angle of about 40 to 40 degrees, and to extend at a high angle of about 60 to 70 degrees with respect to the circumferential direction in the outer region of the tread. With a pattern in which the inner region of the tread is composed of only directional inclined grooves, it is difficult to secure sufficient block rigidity, which causes a problem in steering stability performance. In the pneumatic tire for passenger cars of the present invention, since the pattern is constituted by the directional inclined groove and the central circumferential rib provided in the pattern center as described above,
The circumferential rib adds rigidity to the tread pattern, strengthens the feel of the steering wheel at a small steering angle, enhances the so-called "firm feeling" given to the driver, and improves straight running stability. The central circumferential rib normally refers to a so-called center rib provided on the tire equatorial line in the central portion of the tread, but in the case of a left-right asymmetrical tread pattern, it is offset to about 1/3 of the tread width. It is also possible to provide a direction rib, which is why it is expressed as a "center circumferential rib provided at the pattern center". Further, it is possible to provide two circumferential ribs at the center of the tread to form a so-called center groove.

In the pneumatic tire for passenger cars of the present invention, the circumferential ribs are arranged in the vicinity of the midpoints of the pattern center and both ends of the tread to form two intermediate circumferential ribs, and the directional inclined block has A circumferential groove is formed between the intermediate circumferential rib and the directional inclined blocks arranged on the tread end side of the intermediate circumferential rib, which are arranged on the left and right of the central circumferential rib, or The directional inclined blocks are arranged on the left and right of the intermediate circumferential rib, and the directional inclined blocks arranged on the left and right of the central circumferential rib and the pattern center side of the intermediate circumferential rib. A circumferential groove is preferably formed between the directional tilt block and the directional tilt block. If two intermediate circumferential ribs are formed near the midpoint between the pattern center and both ends of the tread, lateral drainage from the pattern center to both ends of the tread is hindered, so to compensate for this, A circumferential groove is formed on the pattern center side of the intermediate circumferential rib to enhance the drainage function in the front-back direction.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a tread pattern of Embodiment 1 of a pneumatic tire for passenger cars according to the present invention, and FIG.
-A sectional view and FIG. 3 are BB sectional views, the tire size is 225 / 50R16, and the tread width TW is 200 mm. The pneumatic tire of Example 1 shown in FIG. 1 has a central circumferential rib 1 provided on the tire equator E, which is a pattern center, and a circumferential direction from the central circumferential rib 1 to the left and right tread ends TE. The rotational direction R of the tire is designated by including a large number of directional tilt blocks 2 and 3 extending obliquely. The directional inclined blocks 2 and 3 extend in the tread inner region with the block center line inclined at a low angle θ1 of 25 degrees with respect to the circumferential direction, and in the tread outer region with the block center line of 60 degrees with respect to the circumferential direction. High angle θ2
It extends at an angle. A part of the directional tilt block 3 does not impair the circumferential continuity of the circumferential rib 1,
The tip corner portion which is arranged so as to bite into the circumferential rib 1 and which bites into the circumferential rib of the directional inclined block 1 has a tapered acute angle shape, and its angle θ3 is 35 degrees. As shown in the AA cross-sectional view of FIG. 2, the block height of the tip corner portion that bites into at least the circumferential rib of the directional inclined block 3 gradually decreases as it goes into the circumferential rib 1. It ends at 20% of the height of the directional ribs. The directional tilt blocks 2 and 3 are provided on the left and right of the central circumferential rib 1.
It is arranged with a half pitch offset in the circumferential direction. AA of FIG.
As shown in the cross-sectional view, the block height of the inner wide block 3 is the same as that of the central circumferential rib 1 in the tread inner region, and is 20 times the height of the central circumferential rib 1 in the tread outer region.
%, The block height of the outer wide block 2 is the same as that of the central circumferential rib 1 in the tread outer region, and is in the central circumferential direction in the tread inner region, as shown in the BB sectional view of FIG. It is 20% of the height of the rib 1. As shown in FIGS. 2 and 3, the height of the directional inclined block is about 40 to 70% of the distance from the tire equatorial line E, which is the pattern center, to the tread end TE, and the central circumferential rib 1 is provided.
From the same height to 20% of the height of the central circumferential rib, and by changing the height of the outer wide block 2 and the inner wide block 3 at the same position in opposite directions, To form a circumferential groove 6 continuous with.
The block height of the outer wide block 2 is the center circumferential rib 1
Gradually increases in the vicinity of and becomes the same height as the circumferential rib 1,
The block height of the inner wide block 3 is the center circumferential rib 1
20% of the height of the central circumferential rib 1 gradually decreases in the vicinity of
It has become.

FIG. 4 is a tread pattern of Example 2 of the pneumatic tire for passenger cars according to the present invention, and FIG.
In the C sectional view, the tire size is 225 as in the first embodiment.
At / 50R16, the tread width TW is 200 mm.
In the tread pattern of Example 2, the intermediate circumferential rib 5 is arranged near the midpoint between the tire equatorial line E which is the pattern center and the tread ends TE, and the directional inclined block 7 is the tread of the intermediate circumferential rib 5. Example 1 except that a circumferential groove 8 is formed between the directional tilted blocks 6 arranged on the left and right sides of the central circumferential rib 1 on the end TE side and the intermediate circumferential rib 1. The tread pattern is almost the same. FIG. 6 is a tread pattern of Example 3 of the pneumatic tire for passenger cars according to the present invention, and FIG. 7 is a sectional view taken along the line D-D thereof, and similarly to Examples 1 and 2, the tire size is 225 / 50R16 and the tread. Width TW is 200
mm. In the tread pattern of Example 3, the directional tilt blocks 7 and 9 are arranged on the left and right of the intermediate circumferential rib 5, and the directional tilt blocks 6 and the intermediate circumferential rib 5 are arranged on the left and right of the central circumferential rib 1. The tread pattern is substantially the same as that of the first embodiment except that the circumferential groove 8 is formed between the tread pattern 9 and the directional inclined block 9 arranged on the pattern center side.

The conventional pneumatic tire shown in FIG. 8 is a typical example of the tread pattern of the conventional pneumatic tire. As shown in the drawing, five circumferential grooves and a large number of directional inclined grooves are provided. Are arranged at intervals in the circumferential direction. The tire size is 225 / 50R16, and the tread width TW is about 200 mm, both of which are the same as those in the above embodiment. The circumferential groove (63) in the center of the tread has a width of 4
Although it is a narrow groove of mm, a pair of circumferential grooves (62, 64) with a groove width of 11 mm is provided on the left and right sides, and further, it is equivalent to about 1/4 of the tread width from both ends of the tread toward the center of the tread. A pair of circumferential grooves (61, 65) having a groove width of 10 mm are provided at the positions to be formed, and these four thick circumferential grooves and a large number of directional inclined grooves (71, 72, 73, 74, 75,
76) is a tire aiming to greatly contribute to drainage when the tire travels on a wet road surface.

The hydro-planing characteristics, the uneven wear resistance, and the wear resistance of the pneumatic tires for passenger cars of Examples 1 to 3 according to the present invention shown in FIGS. 1 to 7 and the pneumatic tire for passenger cars of the conventional example shown in FIG. An evaluation test of steering stability on a dry road surface was conducted. The test conditions are a tire internal pressure of 2.3 Kg / cm ² , and a straight line hydro planing characteristic is a feeling evaluation of the limit speed of hydro planing generation by a test driver when running on a wet road surface at a water depth of 5 mm, and a hydro planing characteristic at cornering. Comprehensive evaluation of the measured lateral G when passing a test course road surface with a water depth of 5 mm and a radius of 80 m and feeling evaluation of the critical speed of hydroplaning generation by a test driver, high wear resistance on highways and mountain slope roads And the overall evaluation of the step difference between the adjacent blocks and the visual evaluation after running 10,000 km including the city road, the driving stability on the dry road surface was run on the dry circuit course in various running modes. It is the feeling evaluation result of the test driver at that time.

The evaluation results are shown in index form with the result of the pneumatic tire of the conventional example as 100, and the larger the number, the better the performance. Table 1 shows a summary of the evaluation results.

[0020]

[Table 1]

From the results shown in Table 1, the pneumatic tires for passenger cars of the examples according to the present invention are superior to the pneumatic tires for passenger cars of the above-mentioned conventional example in steering stability on dry road surface and uneven wear resistance. It was found that the hydro-planing characteristics were excellent while maintaining the same or excellent performance in all cases.

[0022]

INDUSTRIAL APPLICABILITY The present invention is a high-performance tire which emphasizes athletic performance capable of supporting sports running, and does not deteriorate uneven wear resistance and steering stability on dry roads, and wet road surfaces. It has become possible to provide a new tread pattern for use in pneumatic tires for passenger cars, which has excellent steering stability and hydroplaning characteristics.

[Brief description of the drawings]

FIG. 1 is a tread pattern diagram of a pneumatic tire according to the present invention.

FIG. 2 is a sectional view taken along the line AA of the tread pattern.

FIG. 3 is a BB cross-sectional view of the tread pattern.

FIG. 4 is a tread pattern diagram of a pneumatic tire according to the present invention.

FIG. 5 is a sectional view taken along line CC of the tread pattern.

FIG. 6 is a tread pattern diagram of a pneumatic tire according to the present invention.

FIG. 7 is a cross-sectional view taken along the line DD of the tread pattern.

FIG. 8 is a tread pattern diagram of a conventional typical pneumatic tire.

[Explanation of symbols]

TD Distance from pattern center to tread edge E Tire equatorial line R Tire rotation direction TE Tread edge TW Tread width θ1 Angle of block center line with respect to circumferential direction in tread inner area θ2 Block center line with respect to circumferential direction in tread outer area Angle θ3 Angle of tip corner of directional tilt block 1 Central circumferential rib 2 Directional tilt block 3 Directional tilt block 4 Circumferential groove 5 Intermediate circumferential rib 6 Directional tilt block 7 Directional tilt block 8 Circumferential groove 9 Directional tilt block

Claims (9)

[Claims] 1. At least one circumferential rib extending continuously in the circumferential direction, and a plurality of directional elements extending from the circumferential rib at an angle with respect to the circumferential direction and provided at intervals in the circumferential direction. In a pneumatic tire having a directional tread pattern with an inclined block, (1) a portion of the directional inclined block does not impair the circumferential continuity of the circumferential rib, and the circumferential rib is It is arranged so as to cut into
(2) The tip corner portion that bites into the circumferential rib of the directional tilt block has a tapered acute angle shape, and (3) the block of the tip corner portion that bites into at least the circumferential rib of the directional tilt block. A pneumatic tire characterized in that the height gradually decreases as it bites into the circumferential rib, and ends at 0 to 20% of the height of the circumferential rib. 2. The angle of the tip corner portion of the directional tilted block, which bites into the circumferential rib and forms a tapered acute angle shape, is 20 to 90 degrees. Pneumatic tire. 3. An angle of a tip corner portion of the directional inclined block, which bites into the circumferential rib and forms a tapered acute angle shape, is 30 to 70 degrees. 2. The pneumatic tire described in 2. 4. The pneumatic tire according to claim 1, wherein the directional inclined block bites into the center portion of the circumferential rib and terminates. 5. The circumferential ribs are arranged in a pattern center to form a central circumferential rib, and the directional tilt blocks are arranged on the left and right sides of the central circumferential rib. The pneumatic tires according to 1 to 4. 6. The pneumatic tire according to claim 5, wherein the directional inclined blocks are arranged on the left and right sides of the central circumferential rib with a half pitch shift in the circumferential direction. 7. The directional tilt block continuously extends from the left and right of the central circumferential rib to both ends of the tread, and the block center line of the directional tilt block is 20 to 20 in the tread inner region in the circumferential direction. It extends at a low angle of about 40 degrees, and in the outer region of the tread, it is 60 in the circumferential direction.
7. The pneumatic tire according to claim 5, wherein the pneumatic tire extends at an angle of about 70 to 70 degrees. 8. The circumferential rib is disposed near the midpoint between the pattern center and both ends of the tread to form two intermediate circumferential ribs, and the directional inclined block is the tread end of the intermediate circumferential rib. 7. A circumferential groove is formed between the intermediate circumferential rib and the directional inclined blocks that are disposed on the side of the central circumferential rib and are disposed on the left and right of the central circumferential rib. Pneumatic tire described. 9. The circumferential ribs are arranged near the midpoints of the pattern center and both ends of the tread to form two intermediate circumferential ribs, and the directional inclined blocks are provided on the left and right sides of the intermediate circumferential ribs. Circumferential grooves are formed between the directional inclined blocks arranged on the left and right of the central circumferential rib and the directional inclined blocks arranged on the pattern center side of the intermediate circumferential rib. The pneumatic tire according to any one of claims 5 to 6, wherein: