JPH1191314A - Pneumatic tire for passenger car excellent in drain performance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent low-noise drain performance by extending many tilt grooves curvedly extended in the direction inclined in the peripheral direction of a tire at a specific tilt angle in the peripheral direction of the tire near the opening ends of the central peripheral grooves, and terminating the peripheral discontinuous grooves in blocks without opening them in the tilt grooves. SOLUTION: A tread is provided with a pattern formed with many blocks 4 by many tilt grooves 3 opened to central peripheral grooves 1 and side section peripheral grooves 2 arranged at intervals in the peripheral direction of a tire and curvedly extended in the direction inclined in the peripheral direction of the tire. The tilt grooves 3 are extended at the tilt angle α of 15-45 deg. in the peripheral direction of the tire near the opening ends of the central peripheral grooves 2, and they are extended at the tilt angle βof 40 deg. in the peripheral direction of the tire near the opening ends of the side section peripheral grooves 2. A pair of the right and left peripheral discontinuous grooves 5 discontinuously extended in the peripheral direction of the tire are arranged between the central peripheral grooves 1 and the side section peripheral grooves 2 and are terminated in the blocks 4 without being opened to the tilt grooves 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire, and more particularly, to a tire having a plurality of circumferential grooves extending linearly in a circumferential direction and a plurality of inclined grooves extending in a direction inclined in the circumferential direction. The present invention relates to a pneumatic tire for a passenger car having a so-called block type tread pattern in which a large number of blocks are formed at intervals in an axial direction and a circumferential direction.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional typical pneumatic tire for a passenger car having a block type tread pattern has five circumferential grooves linearly extending in a circumferential direction, and a circumferential groove. A plurality of inclined grooves extending in a direction inclined in the direction provided a tread pattern in which a large number of blocks were formed at intervals in the tire axial direction and the circumferential direction. In the block-type tread pattern as described above, the circumferential groove mainly has a drainage function in the front-rear direction, and the inclined groove mainly has a horizontal drainage function.

[0003]

In the block-type tread pattern as described above, the water flows flowing in different directions collide with each other at the intersection of the circumferential groove and the inclined groove, and the water flow is disturbed. As a result, air bubbles were generated, and the drainage performance deteriorated. In order to avoid such a problem, a pneumatic tire for a passenger car having a tread pattern in which a long inclined groove is arranged so that the circumferential groove does not intersect with the inclined groove has been proposed. In addition, there is a disadvantage that basic performances required for a pneumatic tire for a passenger car, such as vibration riding comfort performance and uneven wear resistance performance, are reduced. Further, in the block-type tread pattern as described above, uneven wear called heel-and-toe wear easily occurs in the shoulder portion, and tire noise due to pattern noise is at a bad level. In order to eliminate this drawback, a design method in which the shoulder block is changed to a rib that is continuous or substantially continuous in the circumferential direction has been conventionally known.However, drainage performance when traveling on a wet road surface is known. The dilemma falls.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pneumatic tire for passenger cars which does not sacrifice basic performances such as steering stability, vibration riding comfort and uneven wear resistance. Another object of the present invention is to provide a pneumatic radial tire for a passenger car which is excellent in low noise performance and drainage performance when traveling on a wet road surface.

[0005]

In order to achieve the above object, a pneumatic tire according to the present invention comprises at least one central circumferential groove which is disposed at the center of a tread and extends continuously in the circumferential direction of the tire. A pair of left and right side circumferential grooves arranged on both sides of the tread and extending continuously in the circumferential direction of the tire;
A large number of blocks are formed by a large number of inclined grooves which are arranged at intervals in the circumferential direction of the tire, open to the central circumferential groove and the side circumferential grooves, and are curved and extend in a direction inclined in the circumferential direction of the tire. In the pneumatic tire provided with the formed pattern on the tread, (1) the inclined groove extends in the circumferential direction of the tire at an inclination angle of 15 to 45 degrees near the opening end of the central circumferential groove. (2) a pair of left and right circumferential discontinuous grooves extending discontinuously in the circumferential direction of the tire are disposed between the central circumferential groove and the side circumferential grooves; A pneumatic tire for a passenger car, wherein the tire terminates in the block without opening to the inclined groove.

In order to achieve the above object, in the pneumatic tire according to the present invention, the circumferential discontinuous groove has a groove width of 1.5 to 4.0 mm, and the circumferential discontinuous groove has a groove width from the terminal edge thereof. It is preferable that the distance to the inclined groove is 1.0 to 4.0 mm.

[0007] In order to achieve the above object, in the pneumatic tire of the present invention, it is preferable that the surface of the sharp corner of the block formed by the inclined groove and the central circumferential groove is chamfered. .

In order to achieve the above object, in the pneumatic tire of the present invention, the distance between the central circumferential groove and the side circumferential groove is set between the side circumferential groove and the tread end. Is preferably larger than the distance of

In order to achieve the above object, in the pneumatic tire of the present invention, a large number of side inclined grooves which are open to the side circumferential grooves and tread ends and extend in a direction inclined in the tire circumferential direction are provided. The side inclined grooves are arranged at intervals in the circumferential direction, and at least in the vicinity of the open end to the side circumferential grooves, the side walls of the grooves come into contact when the tire receives a standard load and contacts the ground. It is preferable that the groove is as thin as possible.
In this specification, “standard load” refers to JATMA issued by the Japan Automobile Tire Association in 1997.
Refers to the mass used for dimensional measurement as defined in YEAR BOOK, that is, 88% of the maximum load capacity in the applicable size ply rating.

The pneumatic tire of the present invention has at least one central circumferential groove disposed at the center of the tread and continuously extending in the circumferential direction of the tire, and at least one central circumferential groove disposed at both sides of the tread and continuous in the circumferential direction of the tire. And a pair of left and right side circumferential grooves extending in the circumferential direction of the tire, and are disposed at intervals in the circumferential direction of the tire, open in the central circumferential groove and the side circumferential grooves, and inclined in the circumferential direction of the tire. By providing the tread with a number of curved grooves extending in a curved manner, it is intended to take on the drainage function of the tire when traveling on a wet road surface. For this reason, it is essential that the inclined groove extends at an inclination angle of 15 to 45 degrees in the circumferential direction of the tire near the opening end of the central circumferential groove. In other words, the inclined groove branches off from the central circumferential groove at an inclination angle of 15 to 45 degrees, smoothly curves and extends, and is opened in the side circumferential groove to ensure smooth drainage with less turbulence. It is essential to
In addition, it is preferable that the inclined groove is opened in the side circumferential groove at an inclination angle of 15 to 45 degrees, because drainage is further improved.
However, at least one central circumferential groove and a pair of left and right side circumferential grooves extending continuously in the circumferential direction of the tire and a large number of inclined grooves extending in a direction inclined in the circumferential direction of the tire are treaded. , There is a concern that the tread may have poor contact with the ground. That is, there is a concern that uneven grounding pressure may cause uneven wear to occur easily, and block rigidity may become too high to deteriorate vibration ride comfort performance. Therefore, in the pneumatic tire of the present invention, a pair of left and right circumferential discontinuous grooves extending discontinuously in the circumferential direction of the tire is arranged between the central circumferential groove and the side circumferential grooves. The continuous groove terminates in the block without opening to the inclined groove. Since such a circumferential discontinuous groove is arranged, a tire having improved tread contact performance and excellent uneven wear resistance and vibration riding comfort can be obtained. In addition, since the circumferential discontinuous groove terminates in the block without opening to the inclined groove, there is no possibility of disturbing the water flow in the inclined groove.

In the pneumatic tire of the present invention, the width of the circumferential discontinuous groove is 1.5 to 4.0 mm, and the distance from the terminal edge of the circumferential discontinuous groove to the inclined groove is 1.0 to 4.0 mm. 0mm
It is preferred that 1.5 groove width of circumferential discontinuous groove
If it is smaller than mm, the groove will be closed by the lateral force of normal handling below the ground contact surface, and it will not be possible to sufficiently reduce the block rigidity. On the other hand, if the groove width of the circumferential discontinuous groove is larger than 4.0 mm, the movement of the block becomes too large, the distortion at the longitudinal end of the discontinuous groove becomes large, and uneven wear easily occurs. If the distance from the terminal edge of the circumferential discontinuous groove to the inclined groove is smaller than 1.0 mm, cracks are likely to occur, and if it is larger than 4.0 mm, the tread's ground contact property is extremely deteriorated.

In the pneumatic tire of the present invention, as described above, at least one central circumferential groove and a pair of left and right side circumferential grooves extending continuously in the circumferential direction of the tire are inclined in the circumferential direction of the tire. With a large number of inclined grooves extending in a curved direction, it is intended to take on the drainage function of the tire when traveling on a wet road surface, so the rib distribution of the tread is important, and the central circumferential groove and Preferably, the distance between the side circumferential grooves is greater than the distance between the side circumferential grooves and the tread ends. As described above, the pneumatic tire of the present invention has a function of draining the tire when running on a wet road surface inside the pair of left and right side circumferential grooves. A number of side inclined grooves that open to the grooves and tread ends and extend in the direction inclined in the tire circumferential direction are relatively thin, such that the side walls of the grooves come into contact when the tire is grounded under the load of the standard load. Even if the groove is formed, the drainage performance of the tire does not extremely decrease. By making the side inclined groove such a thin groove, the shoulder block is changed to a rib that is substantially continuous in the circumferential direction, so that the occurrence of heel-and-toe wear is prevented and the tire due to pattern noise is prevented. The deterioration of the noise level is prevented.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a passenger car tire according to a first embodiment of the present invention; FIG. 2 is a partially enlarged front view of the tread pattern of the tire of Example 1 according to the present invention, and FIG. 2 is a partially enlarged front view of the tread pattern of the tire of Example 2 according to the present invention. 3 is a partially enlarged front view of a tread pattern of a conventional tire. All tire sizes are 185 / 70R14.

The tire according to the first embodiment of the present invention shown in FIG. 1 has two central circumferential grooves 1 which are arranged at the center of the tread and extend continuously in the circumferential direction of the tire, and which are arranged at both sides of the tread. And a pair of left and right side circumferential grooves 2 extending continuously in the circumferential direction of the tire, and a central circumferential groove 1 and side circumferential grooves 2 arranged at intervals in the circumferential direction of the tire. The tread has a pattern in which a large number of blocks 4 are formed by a large number of inclined grooves 3 extending in a direction inclined in the circumferential direction. The inclined groove 3 extends in the circumferential direction of the tire at an inclination angle α of 25 degrees in the vicinity of the opening end of the central circumferential groove 1, and extends 40 degrees in the circumferential direction of the tire in the vicinity of the opening end of the side circumferential groove 2. It extends at an inclination angle β. A pair of left and right circumferential discontinuous grooves 5 extending discontinuously in the circumferential direction of the tire are arranged between the central circumferential groove 1 and the side circumferential grooves 2,
The circumferential discontinuous groove 5 terminates in the block 4 without opening to the inclined groove 3. The groove width of the central circumferential groove 1 is 6
mm, the groove width of the side circumferential groove 2 is 4 mm, the groove width of the inclined groove 3 is 3 to 3.5 mm, and the groove width of the circumferential discontinuous groove 5 is 2 mm. Slant groove 3 from the terminal edge of circumferential discontinuity groove 5
Is 1.5 mm. A sharp corner 41 of the block 4 formed by the inclined groove 3 and the central circumferential groove 1
Surface is smoothly chamfered over a length of 15 mm in the longitudinal direction of the block 4, and the sharp corner 4 of the block 4 also formed by the inclined groove 3 and the side circumferential groove 2.
The surface of No. 2 is chamfered smoothly over 10 mm in the longitudinal direction of the block 4. The distance D between the central circumferential groove 1 and the side circumferential groove 2 is 35 mm, the distance d between the side circumferential groove 2 and the tread end E is 19 mm, and the distance D is 16 mm from the distance d. Only big. The tread width W is 126 mm. A large number of side inclined grooves 6 which are open to the side peripheral groove 2 and the tread end E and extend in a direction inclined in the tire circumferential direction are arranged at intervals in the circumferential direction of the tire. In the vicinity of the opening end to the side circumferential groove 2, the groove has a narrow width of 1 mm, such that the side wall of the groove comes into contact when the tire comes in contact with a standard load and contacts the ground. The standard load is based on JATMA YEAR BO published by the Japan Automobile Tire Association in 1997.
The mass used for dimensional measurement defined in OK, that is, 88% of the maximum load capacity in the applied size ply rating, and the tire size of Example 1 is 1
85 / 70R14, the standard load in this case is 4
95 kg.

A tire according to a second embodiment of the present invention shown in FIG. 2 has two central circumferential grooves 1 arranged at the center of the tread and extending continuously in the circumferential direction of the tire, and arranged at both sides of the tread. And a pair of left and right side circumferential grooves 2 extending continuously in the circumferential direction of the tire, and a central circumferential groove 1 and side circumferential grooves 2 arranged at intervals in the circumferential direction of the tire. The tread has a pattern in which a large number of blocks 4 are formed by a large number of inclined grooves 3 extending in a direction inclined in the circumferential direction. The inclined groove 3 extends at an inclination angle α of 25 degrees in the circumferential direction of the tire near the opening end of the central circumferential groove 1, and extends 70 degrees in the circumferential direction of the tire near the opening end of the side circumferential groove 2. It extends at an inclination angle β. A pair of left and right circumferential discontinuous grooves 5 extending discontinuously in the circumferential direction of the tire are arranged between the central circumferential groove 1 and the side circumferential grooves 2,
The circumferential discontinuous groove 5 terminates in the block 4 without opening to the inclined groove 3. The groove width of the central circumferential groove 1 is 6
mm, the groove width of the side circumferential groove 2 is 5 mm, the groove width of the inclined groove 3 is 2.5 to 4 mm, and the groove width of the circumferential discontinuous groove 5 is 2 mm. Slant groove 3 from the terminal edge of circumferential discontinuity groove 5
Is 2 mm. The surface of the sharp corner 41 of the block 4 formed by the inclined groove 3 and the central circumferential groove 1 is smoothly chamfered over the length of the block 4 by 15 mm. The distance D between the central circumferential groove 1 and the side circumferential groove 2 is 35 mm, the distance d between the side circumferential groove 2 and the tread end E is 19 mm, and the distance D is 16 mm from the distance d. Only big. The tread width W is 126 mm. A large number of side inclined grooves 6 which are open to the side peripheral groove 2 and the tread end E and extend in a direction inclined in the tire circumferential direction are arranged at intervals in the circumferential direction of the tire. In the vicinity of the opening end to the side circumferential groove 2, the groove has a narrow width of 1 mm, such that the side wall of the groove comes into contact when the tire comes in contact with a standard load and contacts the ground. The standard load is based on JATMA YEAR BO published by the Japan Automobile Tire Association in 1997.
The mass used for dimensional measurement defined in OK, that is, 88% of the maximum load capacity in the applied size ply rating, and the tire size of Example 1 is 1
85 / 70R14, the standard load in this case is 4
95 kg.

The conventional tire shown in FIG. 3 has a circumferential groove extending linearly in the circumferential direction at the center of the tread as shown in the figure, and two tires linearly extending circumferentially to the left and right of the center groove. A circumferential groove is provided, and two circumferential grooves extending linearly in the circumferential direction are further provided outside the circumferential groove. These five circumferential grooves and a large number of inclined grooves extending in a direction crossing the tread are provided. And a tread pattern in which a number of blocks are formed at intervals in the tire axial direction and circumferential direction.

With respect to the tires of the first and second embodiments according to the present invention and the conventional tire, the drainage performance of the tire when running on a wet road surface, the noise performance of the tire, and the steering stability of the tire on a dry road surface An evaluation test of performance, vibration riding comfort performance and uneven wear resistance performance was performed. The drainage performance of the tire when traveling on a wet road surface was evaluated by feeling the hydroplaning occurrence limit speed when traveling on a wet road surface with a depth of 5 mm. The evaluation of the sound inside the vehicle when the vehicle coasted from the road was evaluated by feeling.The driving stability of the tires on a dry road surface was measured by a test driver during sports running on a dry circuit course in various driving modes. The vibration ride comfort performance was evaluated by the test driver's feeling when traveling at a speed of 80 km / h on special roads such as joint roads and cobblestone roads. Visually observe uneven wear of the tread after traveling 5000 km in the mode running on urban and mountain slopes. One in which was evaluated by the residual groove measurement.

As a result of the evaluation test, the tires of Examples 1 and 2 according to the present invention are expressed by an index with the performance of the conventional tire being 100, and the tires of Examples 1 and 2 according to the present invention have a lower performance when traveling on a wet road surface. The drainage performance is 120 to 115, the noise performance is 110, the steering stability on a dry road is 100 to 105, the vibration riding comfort is 100, and the uneven wear resistance is 100. there were. The larger the number, the better the performance of the tire. Table 1 summarizes the results of the above evaluation tests.

[0019]

[Table 1]

[0020]

From the above results, it can be seen that, according to the present invention, drainage performance and noise when traveling on a wet road surface without deteriorating the steering stability performance, the vibration riding comfort performance and the uneven wear resistance performance on a dry road surface. It can be seen that a pneumatic tire for a passenger car having excellent performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially enlarged front view of a tread pattern of a tire according to the present invention.

FIG. 2 is a partially enlarged front view of a tread pattern of a tire according to the present invention.

FIG. 3 is a partially enlarged front view of a tread pattern of a conventional tire.

[Explanation of symbols]

 Reference Signs List 1 central circumferential groove 2 side circumferential groove 3 inclined groove 4 block 5 circumferential discontinuous groove 6 side inclined groove E tread end W tread width

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B60C 11/11 B60C 11/08 A

Claims (6)

[Claims] At least one central circumferential groove disposed at the center of the tread and continuously extending in the circumferential direction of the tire, and a pair of left and right central grooves arranged at both sides of the tread and continuously extending in the circumferential direction of the tire. A number of side circumferential grooves, a number of which are arranged at intervals in the circumferential direction of the tire, open to the central circumferential groove and the side circumferential grooves, and are curved and extend in a direction inclined in the circumferential direction of the tire. In a pneumatic tire provided with a pattern in which a large number of blocks are formed by inclined grooves on a tread, (1) the inclined grooves are formed in a circumferential direction of the tire by 15 to 45 near an opening end of the central circumferential groove. (2) a pair of left and right circumferential discontinuous grooves extending discontinuously in the circumferential direction of the tire are disposed between the central circumferential groove and the side circumferential grooves. The circumferential discontinuous groove does not open to the inclined groove. A pneumatic tire for a passenger car, wherein the tire terminates in a lock. 2. The pneumatic tire for a passenger car according to claim 1, wherein a groove width of the circumferential discontinuous groove is 1.5 to 4.0 mm. 3. The pneumatic tire for a passenger car according to claim 1, wherein a distance from an end edge of the circumferential discontinuous groove to the inclined groove is 1.0 to 4.0 mm. 4. The pneumatic tire for a passenger car according to claim 1, wherein a surface of an acute corner of the block formed by the inclined groove and the central circumferential groove is chamfered. 5. The distance between the central circumferential groove and the side circumferential groove is greater than the distance between the side circumferential groove and the tread end. Pneumatic tires. 6. A plurality of side inclined grooves which open in the side circumferential groove and the tread end and extend in a direction inclined in the tire circumferential direction are arranged at intervals in the circumferential direction of the tire. The groove is at least near the open end to the side circumferential groove,
The pneumatic tire according to any one of claims 1 to 5, wherein the tire has a narrow groove such that a side wall of the groove is in contact with the tire when the tire is in contact with a standard load.