JPH08197912A - Pneumatic tire - Google Patents

Abstract

PURPOSE: To provide the pneumatic tire which can enhance wet performance without impairing dry performance by improving each slick area located between each main groove in the circumferential direction of a tire at the outermost side in each outer-side area of the tire in a tread surface and a tread grounding end. CONSTITUTION: In the pneumatic tire which allows a space between a main groove extended along the circumferential direction T of a tire at the outermost side and a grounding end line E to be slick in the tire outer side area O of a tread surface 1 at the outer side from a tire center line CL when the tire is mounted onto a vehicle, an auxiliary main groove 5 which is extended in zigzags along the circumferential direction T of the tire, is provided for the aforesaid slick area, each lug groove 6 which is extended to the grounding end line E toward the outer side of the tire from each outside bent section 5a at the grounding end line E side out of the bent sections 5a and 5b in a zigzag shape each of the auxiliary main groove 5, and each lug groove 7 is also provided, which is communicated with main grooves 2 from the inner side bent sections 5b at each main groove 2 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire particularly used for passenger cars, and more particularly to a pneumatic tire having improved wet performance without impairing dry performance.

[0002]

2. Description of the Related Art For example, as shown in FIG. 2, a plurality of main grooves 12 extending in a tire circumferential direction T are arranged on a tread surface 11, and a lateral groove 13 is formed in a tire inner region I inside from a tire center line CL when a vehicle is mounted. By arranging in the tire width direction,
While forming a large number of blocks 14 divided by the main groove 12 and the lateral groove 13, the lateral groove 13 is provided between the outermost main groove 12 and the tread ground contact end E in the tire outer region O.
There are pneumatic tires for passenger cars that are slicked without the provision of.

In this way, by making the tread ground contact end E side of the tire outer region O into a slick state, steering stability and limit performance (dry performance) on a dry road surface are enhanced. However, on the other hand, when wet, the slick area on the outside prevents drainage to the outside of the tire, so steering stability on wet road surfaces
There was a problem that the marginal performance was significantly reduced.

[0004]

The object of the present invention is to improve the slick area between the outermost tire circumferential main groove and the tread ground contact edge in the tire outer area of the tread surface,
It is to provide a pneumatic tire capable of improving wet performance without impairing dry performance.

[0005]

Means for Solving the Problems The present invention, which achieves the above object, provides an outermost main groove extending along the tire circumferential direction in a tire outer region of a tread surface outside from a tire center line when mounted on a vehicle. In a pneumatic tire having a slick shape between the tread ground contact end, in the slick-shaped area, a quasi-main groove extending in a zigzag shape along the tire circumferential direction is provided, and a zigzag bent portion of the quasi-main groove. Of
A lug groove extending from the outer bent portion on the tread ground contact end side toward the tire outer side to the tread ground contact end is arranged, and a lug groove communicating with the main groove from the inner bent portion on the main groove side is provided. It is characterized by that.

As described above, a quasi-main groove extending in the tire circumferential direction is provided in the conventional slick region in which the slick is formed between the outermost main groove in the tire circumferential direction in the tire outer region of the tread surface and the tread ground contact end. Since the quasi-main groove and the outermost main groove are connected by the lug groove, and the lug groove extending from the quasi-main groove to the tread ground contact end is provided, the quasi-main groove and the lug groove are arranged together. Since the outermost main groove to the tread ground contact end can be communicated with each other through the quasi-main groove and the lug groove, drainage to the outside of the tire can be effectively performed, and thereby, on a wet road surface. The drainage property can be significantly improved and the wet performance can be improved.

In addition, since the inner bent portion of the quasi-main groove formed in a zigzag shape communicates with the outermost main groove, the outermost area of the tire outer area has a convex portion projecting toward the tread ground contact end. Since a large number of blocks are arranged, it is possible to secure block rigidity against lateral force during cornering, and it is possible to maintain substantially the same dry performance as a conventional slick-shaped tire.

The structure of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an example of a tread pattern of the pneumatic tire of the present invention. In the figure,
When mounted on the vehicle, the tread surface 1 is the tire center line CL
To the right side is a tire inner region I, and the left side is a tire outer region O
Is. Such a tread surface 1 has a tire circumferential direction T
A plurality of main grooves 2 extending in a straight shape are provided.

In the tire inner region I, one main groove 2 is arranged adjacent to the tire center line CL, and
Two main grooves 2 are provided outside this with a predetermined interval. Further, a large number of lateral grooves 3 communicating with the main groove 2 are extended along the tire width direction, and a large number of blocks 4 partitioned by the main grooves 2 and the lateral grooves 3 are formed. The lateral groove 3 is arranged with the main groove 2 in contact with the tire center line CL from the middle main groove 2 and the outer main groove 2 with the directions thereof opposite to each other and inclined toward the anti-tire rotation direction side. .

In the tire outer region O, one outermost main groove 2 extending along the tire circumferential direction T and a tread ground contact end E are provided.
Conventionally, a slick shape is provided without a groove, but in the present invention, a quasi-main groove 5 extending in a zigzag shape along the tire circumferential direction T is provided in the slick area. . Zigzag bent portions 5a, 5b of the quasi-main groove 5
Of the lug groove 6 extending from the outer bent portion 5a on the tread ground contact end E side toward the tire outer side to the tread ground contact end E.
Is provided, and a lug groove 7 that communicates from the inner bent portion 5b on the main groove 2 side to the outermost main groove 2 is provided, and is partitioned by the main groove 2, the quasi-main groove 5, and the lug groove 7. A large number of blocks 8 are arranged.

Further, between the main groove 2 in the tire outer region O and the main groove 2 adjacent to the tire center line CL in the tire inner region I, the main groove 2 extending straight in the tire circumferential direction T A narrow circumferential groove 9 is formed, ribs 10 are provided on both sides of the circumferential groove 9, and an asymmetric dread pattern is formed on the tread surface 1. In addition,
The quasi-main groove 5 in the present invention is 10% or more of the groove width of the main groove 2 5
It refers to one having a groove width of 0% or less.

As described above, according to the present invention, the tire circumference is provided in the conventional slick area in which the slick is formed between the outermost main groove 2 in the tire circumferential direction and the tread ground contact end E in the tire outer area O of the tread surface 1. A quasi-main groove 5 extending along the direction is provided, and the outermost main groove 2 and the quasi-main groove 5 are communicated with each other via a lug groove 7.
By arranging the lug groove 6 extending up to, the drainage to the outside of the tire can be satisfactorily performed by the quasi-main groove 5 and the lug grooves 6 and 7, so that the drainage performance on the wet road surface is significantly improved, and the wet performance is improved. Can be improved.

Moreover, since the quasi-main groove 5 is formed in a zigzag shape, and the inner bent portion 5b communicates with the outermost main groove 2, the outermost area of the tire outer area O is projected toward the tread ground contact end E. Since a large number of blocks 8 having the portions 8a are formed, block rigidity can be ensured against lateral force during cornering, and dry performance maintenance that is substantially equivalent to that of a conventional slick-shaped tire can be maintained. enable.

Further, since the zigzag-shaped quasi-main groove 5 is arranged in the tire circumferential direction T, the bent portions 5a and 5b can prevent air columns from being formed and suppress an increase in tire noise. In the zigzag quasi-main groove 5, the relationship between the distance H between the outer and inner bent portions 5a and 5b in the tire width direction and the tread contact width G is set to 0.08 ≦ H / G ≦ 0.16. preferable. When H / G is smaller than 0.08,
Since the protrusion of the convex portion 8a of the block 8 toward the tread ground contact end E side becomes small, the dry performance deteriorates. When H / G becomes larger than 0.16, the convex portion 8 of the block 8
Since a protrudes too much, the dry performance is deteriorated and the chunkout resistance is deteriorated. More preferably, 0.08 ≦ H
It is preferable that /G≦0.14 in order to further improve the wet performance.

The outer bent portion 5 adjacent to the above-mentioned interval H
The ratio H / L of a to the distance L in the tire circumferential direction is 0.5.
The following is recommended. When H / L exceeds 0.5, the dry performance is deteriorated and the chunkout resistance in the block 8 is deteriorated. The inclination angle α of the lug groove 7 with respect to the communicating outer main groove 2 is preferably set in the range of 45 ° <α <135 ° from the viewpoint of uneven wear resistance and durability of the block 8.

In the tire outer region O, the distance between the outermost main groove 2 and the tread ground contact end E is not particularly limited and is preferably within 40% of the tread ground width G. it can. In the present invention, the tread surface 1 of the tire inner region I has a block shape in which a large number of blocks 4 are arranged in the above-described embodiment, but the present invention is not limited to this and may have a shape having ribs.

[0017]

EXAMPLE A tire of the present invention having a tread pattern shown in FIG. 1 and a conventional tire having a tread pattern shown in FIG. 2 were manufactured with the same tire size of 225 / 50R16. Rim size 16 for each of these test tires
It is mounted on the rim of × 8JJ and the air pressure is 230kPa and it is 30
The results are shown in Table 1 when the wet performance and the dry performance evaluation tests were performed under the following measurement conditions by mounting on a 00 cc passenger car. Wet performance Evaluation was performed by a feeling test by a panelist (test driver) on a wet road test course.
The results are shown as index values with the conventional tire being 100. The larger this index value, the better the wet performance. Dry performance Evaluation was performed by a feeling test by a panelist (test driver) on a dry road test course. The results are shown as index values with the conventional tire being 100.
The larger this index value, the better the dry performance.

[0018]

[Table 1] As is clear from Table 1, a slick-shaped area of a conventional tire is provided with a quasi-main groove extending in a zigzag shape along the tire circumferential direction, and a tread touches from the outer bent portion of the quasi-main groove toward the outside of the tire. The tire of the present invention in which the lug groove extending to the end is disposed and the lug groove communicating with the outermost main groove from the inner bent portion is provided has almost no deterioration in dry performance, and the dry performance is substantially equal to that of the conventional tire. It can be maintained that wet performance can be improved without compromising dry performance.

The tire size is the same as above, and the relationship H / G between the tread contact width G and the distance H between the outer and inner bent portions in the tire width direction is changed as shown in Table 2. Test tires 1 to 6 having the tread pattern of H / L = 0.4, inclination angle α = 11
The distance between the outermost main groove and the tread ground contact end in the tire outer region is 0%, which is 20% of the tread ground width G.

Further, the tire size is the same as above, and the ratio H of the distance H between the outer and inner bent portions in the tire width direction to the distance L between the outer bent portions adjacent to each other in the tire circumferential direction.
Test tires 7 to 9 having the tread pattern of FIG. 1 in which / L was changed as shown in Table 3 were produced. H /
Except G = 0.1, the inclination angle α and the distance between the outermost main groove and the tread ground contact end in the tire outer region are the same as described above.

Each of these test tires was subjected to an evaluation test for wet performance and dry performance under the same conditions as above, and an evaluation test for chunkout resistance under the following measurement conditions. The results shown in are obtained. Chunk-out resistance After running 15 laps on a circuit course of 2.0 km per lap at an average speed of 95 km / h, it was examined whether or not block chunk-out occurred on the tread of the mounted tire. ○ indicates that no chunkout occurred, and × indicates that a chunkout occurred.

[0022]

[Table 2]

[0023]

[Table 3] From Table 2, the relationship between the distance H between the outer and inner bent portions in the tire width direction and the tread ground contact width G is 0.08 ≦ H / G.
It can be seen that it is better to set ≦ 0.16. Also, from Table 3,
It is understood that the ratio of the distance H between the outer and inner bent portions in the tire width direction to the distance L between the adjacent outer bent portions in the tire circumferential direction is preferably H / L ≦ 0.5.

[0024]

As described above, according to the present invention, the outermost main groove extending along the tire circumferential direction and the tread grounding end are provided in the tire outer region of the tread surface outside from the tire center line when mounted on a vehicle. In the area where the space is conventionally slicked, a quasi-main groove extending in a zigzag shape along the tire circumferential direction is provided, and among the zigzag-shaped bent portions of the quasi-main groove, the outer bent portion on the tread grounding end side A lug groove extending from the tire to the outside of the tire to the tread ground contact end, and a lug groove communicating with the main groove from the inner bent portion on the main groove side are provided, so that wet performance is not impaired. Performance can be improved.

[Brief description of drawings]

FIG. 1 is a development view of essential parts showing an example of a tread pattern in a pneumatic tire of the present invention.

FIG. 2 is an essential part developed view showing a tread pattern in a conventional pneumatic tire.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 tread surface 2 main groove 3 lateral groove 4 block 5 semi-main groove 5a outer bent portion 5b inner bent portion 6,7 lug groove 8 block I tire inner area O tire outer area T tire circumferential direction CL tire center line

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location 7504-3B B60C 11/04 A

Claims (5)

[Claims] 1. A slick-shaped air inlet between a tread ground contact end and an outermost main groove extending along a tire circumferential direction in a tire outer region of a tread surface outside a tire center line when mounted on a vehicle. In the tire, the slick-shaped region is provided with a quasi-main groove extending in a zigzag shape along the tire circumferential direction, and among the zigzag-shaped bent portions of the quasi-main groove, an outer bent portion on the tread grounding end side. A pneumatic tire provided with a lug groove extending from the tire to the outside of the tire to the tread ground contact end, and a lug groove communicating with the main groove from an inner bent portion on the main groove side. 2. The relationship between the tread contact width G and the distance H between the outer and inner bent portions in the tire width direction is 0.08.
The pneumatic tire according to claim 1, wherein ≦ H / G ≦ 0.16. 3. The ratio H / L of the distance H between the outer and inner bent portions in the tire width direction to the distance L between the adjacent outer bent portions in the tire circumferential direction is 0.5 or less. The pneumatic tire according to 2. 4. The inclination angle α of the lug groove communicating with the main groove with respect to the main groove is 45 ° <α <135 °.
The pneumatic tire according to any one of 1 to 3. 5. A plurality of main grooves extending in the tire circumferential direction are arranged in a tire inner area of a tread surface inside from the tire center line when the vehicle is mounted, and lateral grooves communicating with these main grooves are provided in a tire width direction, The pneumatic tire according to claim 1, wherein a large number of blocks partitioned by the main groove and the lateral groove are formed.