JP2000108615A - Passenger car pneumatic radial tire with directional inclined groove - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the steering stability on a wet road surface without deteriorating the basic performance on a dry road surface by arranging directional inclined grooves so as to be laterally alternately shifted from lateral tread ends by a half pitch. SOLUTION: Directional inclined grooves 2 are extended from lateral tread ends TE to a tread center area TC so as to be laterally alternately shifted by a half pitch, and mutually opened to the opposed other directional inclined grooves 2 in a position exceeding a tire equatorial plane EP. A side circumferential groove 3 extending in parallel to the tire circumferential direction or substantially in parallel thereto and having a small width and depth, compared with a circumferential main groove 1, is arranged in a tread side area TS, and a block formed in the side area TS is divided into an inside block 51 and an outside block 52. The main groove 1 has a width of 8.5 mm and a depth of 9 mm, and the side circumferential groove has a width of 3 mm and a depth of 5.5 mm. A number of sipes 7, 8 are formed on blocks 4, 5 formed in the center area TC and side area TS.

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 in which a tread is substantially equally divided into a central region and a pair of left and right side regions and is parallel or substantially parallel to a tire circumferential direction. A pair of circumferential main grooves extending in the tire circumferential direction, are arranged at intervals in the tire circumferential direction, a number of directional inclined grooves extending in a direction inclined in the tire circumferential direction and opening at the tread end; A plurality of blocks formed at intervals in the tire circumferential direction in the central region and the side regions by a directional inclined groove are provided on the tread, and the directional inclined groove is far from a tread end of a portion where the groove extends. The invention relates to an all-weather pneumatic tire having a directional tread pattern in which the tire rotation direction is specified when the tire is mounted on a vehicle such that the side of the tire contacts the tread first and the side near the tread edge contacts the rear. .

[0002] In the present specification, a "directional inclined groove" is a groove extending in a direction inclined with respect to a circumferential direction.
As the side farthest to the tread end of the portion of the groove extending obliquely touches the ground first, and the side close to the tread end touches the ground later,
This means a groove in which a so-called directional tread pattern is formed, in which the direction of rotation (normal rotation) of the tire when mounted on a vehicle is specified.

[0003]

2. Description of the Related Art Conventionally, an all-weather pneumatic tire has a circumferential groove extending linearly and / or zigzag with respect to the circumferential direction, an inclined groove extending in a direction inclined with respect to the circumferential direction, and a circumferential groove extending in the circumferential direction. The tread has a block pattern composed of a number of blocks formed by directional grooves and inclined grooves, and the block has a number of sipes formed thereon, and the block and the edge components of the sipes ran on ice and snow. It tries to improve the traction performance and braking performance at the time. However, if the block rigidity is reduced by forming a large number of sipes in the block, not only the steering stability on a dry road surface and the steering stability performance on a wet road surface, but also the steering stability performance when traveling on snow is reduced. In addition, in order to enhance traction performance when traveling on ice and snow, it is preferable that the inclined groove extending in the direction inclined with respect to the circumferential direction be a gentle inclined groove extending at a large inclination angle with respect to the circumferential direction. Drainage performance when traveling on a wet road surface is reduced, and the noise level of tires is deteriorated. Furthermore, when a circumferential groove extending linearly in the circumferential direction for drainage in the front-rear direction and a groove extending in a different direction in which the groove extends, represented by an inclined groove for horizontal drainage, intersect, At the intersections, the water flows flowing along the respective grooves collide with each other, so that turbulence occurs, which causes a problem that bubbles are generated and the drainage performance is reduced.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages of the prior art and reduce the basic required performance such as steering stability performance and tire noise performance on a dry road surface. An object of the present invention is to provide an all-weather pneumatic tire that is excellent in drainage performance when traveling on a wet road surface and steering stability performance when traveling on snow.

[0005]

In order to achieve the above object, a pneumatic tire according to the present invention is arranged so that a tread is substantially equally divided into a central region and a pair of left and right side regions. A pair of circumferential main grooves extending parallel or almost parallel to the direction, are arranged at intervals in the tire circumferential direction,
A large number of directional inclined grooves extending in a direction inclined in the tire circumferential direction and opening at the tread end, and the circumferential main grooves and the directional inclined grooves provide an interval in the tire circumferential direction in the central region and the side regions. The tread is provided with a large number of blocks formed on the tread, and is mounted on a vehicle such that the side of the portion of the directional inclined groove extending farther from the tread end contacts first, and the side closer to the tread end contacts later. In the pneumatic tire provided with the directional tread pattern in which the rotation direction of the tire at the time is specified, (1) the directional inclined groove is shifted from the left and right tread ends by half pitch alternately left and right, and Extending to the central region, mutually open to the other directional inclined groove opposed at a position beyond the tire equatorial plane, and (2) extending parallel or substantially parallel to the tire circumferential direction in the tread side region; Circumferential direction Narrower than the groove depth is disposed shallow side circumferential groove, formed in the side region block is divided into an inner block and the outer block,
(3) A pneumatic radial tire for an all-weather passenger car, wherein a large number of sipes are formed in the blocks formed in the central region and the side regions.

In order to achieve the above object, in the pneumatic tire of the present invention, at least the sipe formed in the block in the tread central region extends in a direction intersecting the direction in which the directional inclined groove extends. The sipe formed in the block in the tread central region and the block inside the side region extends in a direction intersecting the direction in which the directional inclined groove extends, and extends outside the side region. The sipe formed in the block of the directional inclined groove extends in parallel or almost parallel to the direction in which the directional inclined groove extends,
It is preferable that a large number of the sipes formed in the block are connected by a shallow sipes formed in the center of the block.

In order to achieve the above object, in the pneumatic tire according to the present invention, one of the directional inclined grooves is formed by mutually opening in the other directional inclined groove opposed in the tread central region. The amplitude of the zigzag central groove is 30 to 40% of the width of the tread central region, and the vicinity of the directional inclined groove opening to the other directional inclined groove facing the tread central region. The groove depth is shallow, the directional inclined groove extends at an angle of 30 to 50 degrees in the tire circumferential direction in the tread central region, and the directional inclined groove is In the region, it preferably extends at an angle of 50 to 85 degrees in the tire circumferential direction.

In order to achieve the above object, in the pneumatic tire of the present invention, the circumferential main groove extends in the circumferential direction of the tire with a small amplitude that can be seen in the circumferential direction. Pitch is the same as the circumferential interval between the adjacent directional inclined grooves, and the saw-tooth waves of the pair of left and right circumferential main grooves are inclined in the same direction as the direction of the directional inclined grooves. , Preferably extending at an angle of 3 to 5 degrees in the tire circumferential direction.

In order to achieve the above object, in the pneumatic tire of the present invention, the side circumferential groove extends parallel or substantially parallel to the circumferential main groove, and the width of the side circumferential groove is set to the width. Not more than about 35% of the groove width of the circumferential main groove, and the surface of the block inside the side area on the side adjacent to the circumferential main groove is chamfered over a width of 2 to 4 mm. Is preferred.

[0010] The pneumatic tire of the present invention has the above-described structure. In particular, the tread is divided into a central region and a pair of left and right side regions by a pair of circumferential main grooves extending parallel or substantially parallel to the tire circumferential direction. , The circumferential main groove and the directional inclined groove impart sufficient block rigidity to the block rows formed in the tread central region and the tread side region. That is, if the tread is divided into four parts instead of three parts, the width of the block row becomes too small, and particularly, the rigidity of the handle is insufficient due to the reduced block rigidity in the tread central area, and the block rigidity is reduced in the tread side area. Insufficient grip when cornering. If the tread is divided into two parts, the rigidity of the block is secured, but the width of the circumferential main groove at the center of the tread needs to be increased in order to secure drainage performance when traveling on a wet road surface, There is a problem that the steering stability is deteriorated due to a decrease in the rigidity of the region.

[0011] The pneumatic tire of the present invention has the above-described structure. In particular, the pneumatic tire extends in the tread side region in parallel or substantially parallel to the tire circumferential direction, and is narrower in width and deeper than the circumferential main groove. Shallow side circumferential grooves are arranged, so that the blocks formed in the side regions are divided into inner and outer blocks without significantly impairing the block rigidity, increasing the edge effect and improving tire contact Thus, traction performance, braking performance and cornering performance when traveling on ice and snow can be improved.
The width of the side circumferential groove is preferably about 35% or less of the width of the circumferential main groove so that the block formed in the side area does not significantly impair the block rigidity. In order to ensure drainage performance when traveling on a rough road surface, the side circumferential grooves extend parallel or substantially parallel to the circumferential main grooves, and are inclined in the same direction as the directional inclined grooves, and are inclined in the tire circumferential direction. Preferably, it extends at an angle of from 5 to 5 degrees.

The pneumatic tire of the present invention has the above-mentioned structure. In particular, the directional inclined groove extends from the left and right tread ends to the central region of the tread alternately by half a pitch from the right and left tread ends, and crosses the tire equatorial plane. Directional slopes are open to each other at the same position, so traction performance when traveling on ice and snow and drainage performance when traveling on wet road surfaces are basically ensured, By arranging the inclined grooves so as to be shifted by a half pitch alternately on the left and right sides, the problem that the noise level of the tire is deteriorated is prevented. In addition, the zigzag-shaped central groove is formed by opening one directional inclined groove to the other directional inclined groove opposite in the tread central area, so traction performance when traveling on ice and snow is ensured. Is done. Further, in the directional inclined groove, the side farther from the tread end of the portion where the groove extends comes into contact with the ground first, and the side near the tread end comes into contact with the ground later. Open to the groove. As a result, the water flow smoothly flows from the directional inclined groove to the circumferential main groove in the central region of the tread, and the flow does not disturb.

[0013] The pneumatic tire of the present invention has the above-described structure. In particular, the directional inclined groove extends at an angle of 30 to 50 degrees in the tire circumferential direction in the tread central region. In the tread side region, the tire extends in the circumferential direction at an angle of 50 to 85 degrees, so that the traction performance when traveling on ice and snow, the drainage performance when traveling on a wet road surface and the balance of pattern noise are improved. Preferred to keep optimal.

[0014] The pneumatic tire of the present invention has the above-described structure. In particular, the depth of the groove becomes shallow near the opening of the directional inclined groove in the opposite directional inclined groove in the center region of the tread. This is preferable in order to keep the rigidity of the block row large in the tread central region and to prevent the flow from being disturbed at the location where the directional inclined groove opens to the other opposing directional inclined groove.

The pneumatic tire according to the present invention has the above-described structure. In particular, the sipe formed in the block in the tread central region and the block inside the side region are arranged in the direction in which the directional inclined groove extends. The sipe is easy to open when stepping on the block because it extends in the intersecting direction, and the edge effect of the sipe increases, and the traction effect of the inclined groove is reduced because the open sipe does not clog the snow and narrow the width of the inclined groove. Not reduced.

[0016] The pneumatic tire of the present invention has the above-described configuration. In particular, since a large number of sipes formed in the blocks are connected by a shallow sipes formed substantially at the center of each block, The contact property of the tire improves.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The tires of Examples 1 and 2 and the conventional tire according to the present invention will be described below with reference to the drawings. All tire sizes are 195/6
5R15.

In the tire according to the first embodiment shown in FIG. 1, the tread has a central area TC and a pair of left and right side areas T.
S and a pair of circumferential main grooves 1 extending substantially in parallel with the tire circumferential direction and arranged at intervals in the tire circumferential direction and extending in a direction inclined in the tire circumferential direction. Many directional inclined grooves 2 opening at tread edge TE
And a plurality of blocks 4, 5 formed in the central area TC and the side area TS at intervals in the tire circumferential direction by the circumferential main groove 1 and the directional inclined groove 2, and provided in the tread. End T of the portion where the groove of the inclined groove 2 extends
Air for all-weather passenger vehicles having a directional tread pattern in which the tire rotation direction RD is specified when the tire is mounted on a vehicle such that the side farther to E comes in contact with the ground first and the side closer to the tread end TE comes in contact with the ground later. Radial tires. The directional inclined groove 2 extends from the left and right tread ends TE alternately by half a pitch to the tread center region TC, and is mutually opposed to the other directional inclined groove 2 facing the tire equatorial plane EP. It is open. The side circumferential groove 3 extends in the tread side region TS in parallel or substantially parallel to the tire circumferential direction, and has a smaller width and a smaller depth than the circumferential main groove 1.
Are arranged, and the block 5 formed in the side area TS is divided into an inner block 51 and an outer block 52. In the tire of Example 1, the width of the circumferential main groove 1 is 8.
5 mm, depth 9 mm, width of side circumferential groove 3 is 3
mm and a depth of 5.5 mm. A large number of sipes 7 and 8 are formed in the blocks 4 and 5 formed in the central area TC and the side area TS. Sipe 7 formed in block 4 in the tread central region and block 51 inside the side region extends in a direction crossing the direction in which directional inclined groove 2 extends, and is formed in block 52 outside the side region. The sipe 8 extends parallel or almost parallel to the direction in which the directional inclined groove 2 extends. A large number of sipes 7, 8 formed in the blocks 4, 5 are connected by a shallow sipe 9 formed in the center of the block. Although the groove depth of the directional inclined groove 2 is 9 mm,
However, in the vicinity of the opening in the other directional inclined groove 2 opposite in the tread central area TC, the groove depth is as small as 5.5 mm. The directional inclined groove 2 extends at an angle of 40 to 45 degrees in the tire circumferential direction in the tread central area TC,
On the other hand, the tread side region TS extends at an angle of 60 to 80 degrees in the tire circumferential direction. As shown in the figure, the circumferential main groove 1 extends in a sawtooth shape in the tire circumferential direction with an amplitude that can be seen in the circumferential direction, and the pitch of the sawtooth wave is the same as the circumferential interval of the directional inclined groove. . The sawtooth wave of the pair of left and right circumferential main grooves 1 is inclined in the same direction as the direction of the directional inclined groove 2 and extends at an angle of 5 degrees in the tire circumferential direction. The side circumferential groove 3 extends in a sawtooth shape parallel to the circumferential main groove 1, and the groove width of the side circumferential groove 3 is about 35% of the groove width of the circumferential main groove 1.

The tire according to the second embodiment shown in FIG. 2 is different from the tire in that the sipes 7, 8 formed in the blocks 4, 5 in the central area TC and the side area TS extend not in a straight line but in a zigzag shape. Thus, it is almost the same as the tire of the first embodiment.

The conventional tire shown in FIG. 3 has five circumferential grooves which are arranged at intervals in the tire axial direction and extend in the circumferential direction, and are arranged at intervals in the tire circumferential direction. Or, a tread in which a number of lateral grooves extending substantially in the axial direction, and a number of blocks formed at intervals in the tire axial direction and the tire circumferential direction by the circumferential grooves and the lateral grooves are formed on the tread.・ It has a pattern.

With respect to the tires of Examples 1 and 2 and the conventional tire according to the present invention, the steering stability performance when traveling on snow, the drainage performance when traveling straight on a wet road surface, and the performance on a dry road surface Evaluation tests of steering stability performance and tire noise performance were conducted.

The steering stability performance when traveling on snow is evaluated by comprehensive evaluation of braking performance, starting performance, straight running performance and cornering performance on a test road on a snow-covered snowy road.
The drainage performance when traveling on a wet road surface is based on the feeling evaluation of the hydroplaning occurrence limit speed when traveling on a wet road surface with a depth of 5 mm.・ Tests performed when running the course in various modes of sports
The tire noise performance is obtained by evaluating the in-vehicle noise when the vehicle coasts on a straight road from 100 km / h by feeling.

As a result of the above evaluation test, assuming that the tire of the conventional example is 100, the tires of Examples 1 and 2 according to the present invention have steering stability performances of 120 and 115 when running on snow, and are wet. The drainage performance when driving on the road surface was 115, and the steering stability performance on dry road surface was 1
05 and 110, and the tire noise performance is 110
Met. In each case, the larger the number, the better the performance of the tire.

[0024]

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

[Brief description of the drawings]

FIG. 1 is a partially enlarged front view of a tread pattern of a tire.

FIG. 2 is a partially enlarged front view of a tread pattern of a tire.

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

[Explanation of symbols]

 Reference Signs List 1 circumferential groove 2 directional inclined groove 3 side circumferential groove 4 block 5 block 7 sipe 8 sipe 9 shallow sipe 51 inner block 52 outer block TC tread central region TS tread side region TE tread end RD tire rotation Direction EP Tire equatorial plane

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60C 11/12 B60C 11/04 D 11/06 B

Claims (12)

[Claims] 1. A pair of circumferential main grooves arranged to divide the tread into a central region and a pair of left and right side regions so as to be substantially equal to three, and extending parallel or substantially parallel to the tire circumferential direction. A plurality of directional inclined grooves which are arranged at intervals and extend in a direction inclined in the tire circumferential direction and open at the tread end; and the central region and the side regions defined by the circumferential main groove and the directional inclined grooves. A large number of blocks formed at intervals in the tire circumferential direction are provided on the tread, the side of the portion of the directional inclined groove extending far from the tread end is grounded first, and the side near the tread end is grounded later. In a pneumatic tire having a directional tread pattern in which the rotation direction of the tire when mounted on a vehicle is specified, (1) the directional inclined grooves are formed from the left and right tread ends.
The tire extends rightward and leftward alternately by a half pitch to the center area of the tread, and mutually opens at the opposite directional inclined groove at a position beyond the equatorial plane of the tire. Parallel or substantially parallel to the direction, a side circumferential groove having a smaller width and a smaller depth than the circumferential main groove is arranged, and the blocks formed in the side region are an inner block and an outer block. (3) A pneumatic radial tire for an all-weather passenger car, wherein a large number of sipes are formed in the blocks formed in the central region and the side regions. 2. The pneumatic pump according to claim 1, wherein the sipe formed in at least the block in the tread central region extends in a direction crossing a direction in which the directional inclined groove extends. tire. 3. The sipe formed in the block in the tread central region and the block inside the side region extends in a direction intersecting the direction in which the directional inclined groove extends, and 3. The pneumatic tire according to claim 2, wherein the sipe formed in the outer block extends parallel or substantially parallel to a direction in which the directional inclined groove extends. 4. The pneumatic tire according to claim 1, wherein a number of said sipes formed in said block are connected by a shallow sipes formed in a central portion of said block. 5. The amplitude of a zigzag central groove formed by one of said directional inclined grooves being mutually open to said other directional inclined groove in said tread central region,
The pneumatic tire according to any one of claims 1 to 4, wherein the width of the tread central region is 30 to 40%. 6. The groove according to claim 1, wherein the depth of the directional inclined groove is shallow in the vicinity of the opening of the other directional inclined groove facing the center of the tread.
The pneumatic tire as described. 7. The pneumatic tire according to claim 1, wherein the directional inclined groove extends at an angle of 30 to 50 degrees in the tire circumferential direction in the tread central region. 8. The pneumatic tire according to claim 1, wherein the directional inclined groove extends at an angle of 50 to 85 degrees in the tire circumferential direction in the tread side region. 9. The circumferential main groove extends in the circumferential direction of the tire in a saw-tooth shape with an amplitude that can be seen in the circumferential direction, and the pitch of the saw-tooth wave is equal to the circumferential interval between the adjacent directional inclined grooves. The pneumatic tire according to claim 1, wherein the tire is the same. 10. The sawtooth wave of the pair of left and right circumferential main grooves is inclined in the same direction as the direction of the directional inclined groove and extends at an angle of 3 to 5 degrees in the tire circumferential direction. The pneumatic tire according to claim 9, wherein: 11. The side circumferential groove extends parallel or substantially parallel to the circumferential main groove, and a groove width of the side circumferential groove is about 35% or less of a groove width of the circumferential main groove. The pneumatic tire according to any one of claims 1 to 10, wherein 12. The surface of the block inside the side region on the side adjacent to the circumferential main groove is chamfered over a width of 2 to 4 mm. Pneumatic tires.