JPH0310911A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To avoid hydro-planing and decrease pattern noise by forming oblique grooves, which are composed of plural portions and produce plural blocks through arranging them between a peripheral main groove and a peripheral side groove, and also by dividing each block into plural sub-blocks using narrow grooves. CONSTITUTION:On a tread portion T, there are one peripheral main groove 1, a pair of two peripheral side grooves 2, plural oblique grooves 4 and 7. By these grooves, plural block trains 6, 9, which include plural blocks 5, 8, respectively, are formed. In this constitution, each oblique groove 4 is composed of an inner part 4a neighboring with the peripheral main groove 1, an outer part 4b neighboring with the peripheral side groove 2 and an intermediate part 4c, which is located between the grooves 4a and 4b and elongated to the peripheral direction. Each block 5 within the block 6 is divided into plural sub-blocks 5a, 5b, which are located in outer and inner sides of the tire width, by narrow grooves 10, which have such an aperture that side walls contact with each other during rolling of the tire under load.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a high-performance pneumatic tire for passenger cars. This makes it possible to achieve significant reductions.

(Prior Art) Some conventional high-performance tires for passenger cars have a tread pattern as shown in FIG. 3, for example.

This is achieved by providing a center narrow groove 111 extending linearly in the circumferential direction of the tire in the central portion of the tread surface T, and at the same time providing a center narrow groove 111 on each side of the center narrow groove 111 with the narrow groove 111 separated. Two pairs of circumferential straight grooves 11
2.113 are provided at predetermined intervals in the tire width direction, and each transverse main groove 114 extending from the center narrow groove 111 to each tread edge is formed from the narrow groove 111 to the tread tread edge. The tire is inclined so that it tends to be located toward the rear in the rotational direction of the tire as the tire moves toward the rear. According to such a tire, it is possible to provide excellent handling stability under high block rigidity, and also to provide mainly Due to the action of a large number of circumferential grooves, it is possible to improve drainage performance and prevent the occurrence of hydroplaning.

(Problems to be Solved by the Invention) However, with such conventional tires, the comfort of the vehicle interior is impaired due to pattern noise, and the performance of suppressing the hydroplaning phenomenon is not yet fully satisfactory. was there.

Therefore, for the purpose of reducing pattern noise, the lateral grooves extending in the direction intersecting with the circumferential grooves are offset in the circumferential direction of the tire in the middle of the extending direction, and the negative ratio of the lateral grooves is In addition, with the aim of effectively suppressing the hydroplaning phenomenon, it has been proposed to increase the width of the circumferential grooves to reduce the number of grooves, and to increase the width of each lateral groove on the tire. Proposals include making the grooves extend in an approximately seven-figure shape when viewed from the front, and increasing the negative ratio of the lateral grooves.

However, if the width of the circumferential grooves is increased and the number of circumferential grooves is decreased in order to suppress the hydroplaning phenomenon, the width of the ridges defined by these grooves becomes too wide, resulting in poor ground contact. As a result, road grip force and steering stability are reduced.Also, increasing the negative ratio of the lateral groove improves drainage performance but increases pattern noise. If the directional grooves are simply offset in the circumferential direction of the tire, drainage performance is reduced and hydroplaning becomes more likely to occur.

This invention takes into consideration these mutually contradictory phenomena and finds a groove structure that improves wet performance while ensuring sufficient ground contact, and also creates a lateral groove structure that reduces pattern noise without reducing drainage performance. This pneumatic tire was developed based on the discovery of an offset method for this, and can sufficiently prevent the occurrence of hydroplaning without sacrificing handling stability, and can significantly reduce pattern noise. It provides:

(Means for Solving the Problems) The pneumatic tire of the present invention has at least one circumferential main groove extending in the central region of the tread road surface, and at least one circumferential main groove located on each side of the circumferential main groove. , a pair of circumferential side grooves extending substantially parallel to the circumferential main groove, and extending between the circumferential grooves and between the circumferential side grooves and the tread edge, a plurality of first and second inclined grooves that partition a first block row closer to the tread center and a second block row closer to the tread end, the plurality of first and second inclined grooves being separated by the circumferential main groove; at least a first inclined groove located at a
A tire that is spaced apart from each other in a direction of rotation from the front side to the rear side of the tire, wherein the first inclined groove is formed between an inner end portion located close to the circumferential main groove and a circumferential side side. Each block of the first block row is composed of an outer end portion located close to the groove, and an intermediate portion located between these end portions and extending approximately in the circumferential direction of the tire. sub-blocks located on the inner and outer sides in the width direction of the tire, each having a groove width such that the groove walls come into contact with each other during load rolling; It is divided into

Here, the intermediate portion of the first inclined groove and the narrow groove located across the circumferential main groove are separated from each other from the front side to the rear side in the rotational direction of the tire, and the intersection angle between them and the circumferential main groove is is preferably in the range of 1° to 10°, and it is also preferable that the groove width at the inner end portion of the first inclined groove gradually widens toward its outer end portion.

Furthermore, in each of the sub-blocks divided by the narrow grooves, the inner sub-block is moved forward in the rotational direction of the tire relative to the outer sub-block over a distance of 50 to 20% of the circumferential length of the tire. It is preferable to proceed with the arrangement.

(Function) In this tire, by extending at least the first inclined groove located across the circumferential main groove in a substantially V-shape when viewed from the front of the tire, drainage performance on wet road surfaces is sufficiently improved. In addition, each of the first inclined grooves, in particular, the inner end portion thereof located close to the circumferential main groove and the outer end portion located close to the circumferential side groove thereof. By offset in the circumferential direction of the tire by the intermediate portion located between both end portions and extending approximately in the circumferential direction of the tire, pattern noise can be reduced without impairing drainage performance. Drainage performance is improved by communicating the circumferentially adjacent intermediate portions with narrow grooves and dividing the block, which is divided by a small number of wide circumferential grooves, into two sub-blocks inside and outside in the width direction of the tire. The block's grounding performance can be improved even when the tire height is increased, and by setting the groove width of the narrow groove to such a size that the groove walls come into contact with each other when the tire is rolling under load, the decrease in block rigidity is effectively suppressed. Therefore, the occurrence of hydroplaning can be sufficiently prevented without impairing steering stability, and pattern noise can be greatly reduced.

Here, the intermediate portion of the first inclined groove and the narrow groove are separated from each other from the front side in the rotational direction of the tire toward the rear side between them, which are located across the circumferential main groove. By doing so, the drainage resistance due to these grooves can be reduced and smooth drainage can be ensured.
This is particularly noticeable when the range is set to .

This means that if the intersection angle is less than 1°, water will not flow smoothly from the inclined groove to the middle part and from the middle part to the inclined groove, and if it exceeds 10°, there will be a circumferential phase difference between the inner and outer sides. This is because the difference between the inclined groove portion and the intermediate portion becomes unclear.

Furthermore, if the groove width of the first inclined groove is gradually expanded toward its outer end, the road impact component when stepping on the block is reduced, effectively preventing pattern noise from occurring. In addition, a smoother flow of water in the widening direction is provided, and furthermore, the inner sub-block is
The effect based on the presence of the intermediate portion of the first inclined groove can be improved by locating it further forward in the rotational direction of the tire than the outer sub-block over a distance in the range of 50 to 20% of the circumferential length of the tire. It can be made more prominent. In other words, if it is less than 20%, pattern noise reduction is not sufficient, and if it exceeds 50%, it is 1,
Drainage performance will be reduced.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a tread pattern showing one embodiment of the present invention. The internal structure of the tire is omitted from illustration because it is similar to that of a radial tire for boat fishing.

Here, one circumferential main groove 1 extending linearly is provided in the center of the tread surface portion T, and a pair of circumferential main grooves 1 are provided on each side of the circumferential main groove 1. The circumferential side grooves 2 extending substantially parallel to each other are connected to the circumferential main groove 1 thereof.
The first inclined groove 4 is provided at a predetermined interval from the circumferential main groove 1 and the circumferential side groove 2, and the tire is A first block row 6 consisting of a plurality of blocks 5 positioned at regular intervals in the circumferential direction of The grooves 7 each define a second block row 9 consisting of a plurality of blocks 8 which are also located at regular intervals in the circumferential direction of the tire, and at least a second block row 9 which is also located at regular intervals in the circumferential direction of the tire. 1 oblique groove 4, double-ended oblique groove 4 in the figure
, 7 tend to be separated from each other from the front side toward the rear side in the rotational direction of the tire, and the degree of separation is reduced by the first inclined groove 4.

Further, here, the first inclined groove 4 is defined as an inner end portion 4a located close to the circumferential main groove 1, an outer end portion 4b located close to the circumferential side groove 2, and both ends thereof. and intermediate portions 4C located between the portions and extending substantially in the circumferential direction of the tire, and more preferably, each intermediate portion 4C located across the circumferential main groove 1 is located on the front side in the rotational direction of the tire. The intermediate portions 4C are separated from each other toward the rear side, and the intersection angle between each intermediate portion 4C and the circumferential main groove 1 is within the range of 1° to 10°, so that the drainage resistance due to the intermediate portions 4C is sufficiently equalized. .

Furthermore, by bringing the respective intermediate portions 4C adjacent in the circumferential direction of the tire into communication with each other through the narrow grooves 10 having a groove width such that the groove walls contact each other during load rolling of the tire, the first block Each block 5 in column 6 is
It is divided into a sub-block 5a located on the inside in the tire width direction and a sub-block 5b located on the outside thereof, thereby preventing a decrease in the rigidity of the block 5 and improving ground contact.

Preferably, the width of the inner end portion 4a of the first inclined groove 4 is gradually expanded toward the outer end portion of the block 5, particularly the sub-block 5a.
This reduces the pattern noise that occurs when a collision occurs with the road surface, and also makes the water discharge outward in the width direction of the tire smoother. Over distances ranging from ~20%,
By locating the outer sub-block 5b further forward in the rotational direction of the tire, under the action of the intermediate portion 4C of the first inclined groove 4, drainage performance is not reduced.
Achieve effective reduction of pattern noise.

In this example, within the tread surface portion, each block 8 of the second block row 9 also extends obliquely in the same direction as the above-mentioned narrow grooves 10, so that the second inclined grooves 7 communicate with each other. By forming the narrow grooves 11 that bring about this, the block 8 is divided into an inner sub-block 8a and an outer sub-block 8b, thereby effectively preventing a decrease in the rigidity of the block 8 and improving the grounding performance of the block 8. bring about.

Thus, according to the invention, each block 5, 8 delimited by the circumferential groove 1.2 and the inclined grooves 4, 7
In addition to being able to provide excellent handling stability under the high rigidity of To advantageously reduce pattern noise without reducing drainage performance by offsetting the inner end portion 4a and outer end portion 4b of the first inclined groove 4 in the circumferential direction of the tire by the intermediate portion 4C. I can do it.

In addition, each intermediate portion 4 adjacent in the circumferential direction of the tire
By communicating C with the narrow grooves 10, it is possible to effectively prevent a decrease in the rigidity of the block 5 and improve the grounding performance.
As a result, without sacrificing handling stability,
The tire's road grip and drainage performance can be greatly improved.

FIG. 2 is a diagram showing another embodiment of the present invention, in which two mutually parallel circumferential main grooves 1 are provided in the central part of the tread surface T, so that there is a straight line between them. Due to the partitioning of the shaped ribs and the formation of the ribs 12, the width of the blocks 8 located within the tread surface portion becomes narrower, or in other words, the problem arises that the grounding performance of the blocks 8 decreases. Therefore, this embodiment differs from the previous embodiment in that the division of block 8 into sub-blocks is omitted.

Also in this embodiment, since the configuration of the main parts is the same as that of the previous embodiment, it is possible to bring about the same effects as described for that embodiment.

[Comparative example]

Comparative tests between the invention tire and the conventional tire regarding hydroplaning suppression performance, driving stability on dry road surfaces, and pattern noise will be described below.

◎Test tire size: PSR225150VR16 Invention tire I A tire having a tread pattern shown in FIG.
2 widths are 13, 5 mm, and 12.0 mm, respectively, and the widths of the inner end portion 4as, outer end portion 4b, and intermediate portion 4C in the first inclined groove are 1 to 3 mm, and 3 to 5 mm, respectively.
and 3 mm, the width of the second inclined groove is 5 to 7 mm, the width of each narrow groove io and ti is 1 mm, the intersection angle θ between the narrow groove 10 and the circumferential main groove 1 is 4°, the narrow groove 11 and the circumferential main groove 1 is 6 degrees, and the amount of advancement of the inner sub-block 5a with respect to the outer sub-block 5b! ! /Lxloo=
40% - Invention Tire■ A tire having the tread pattern shown in Fig. 2, in which the width of each circumferential main groove 1 is 11.5 mm, the width of each circumferential main groove 2 is 10.5 mm, and a rib. The width of tire 12 was 15, and the dimensions of other parts were the same as tire I of the invention. ◎Test method: An actual vehicle was run under the normal internal pressure and normal load based on the JIS standard, and the performance of suppressing the hydroplaning phenomenon was tested. About 1100km/h on a wet road with a water depth of 5mm
The pattern noise was determined by evaluating the driving feeling and the measured value of the remaining ground contact area when driving on a dry road, and the steering stability on dry roads was determined by evaluating the feeling when driving on a dry circuit. Pattern noise evaluation Each pattern noise was determined by feeling evaluation when driving on the road surface.

◎Test Results The above test results are shown in the table below, with those of conventional tires set as an index of 100.

Note that the larger the index value, the better the result. The results shall be shown.

According to this table, all of the invented tires advantageously achieve improved performance in suppressing hydroplaning and reduced pattern noise, without impairing steering stability on dry roads, compared to conventional tires. It is clear what you get.

(Effects of the Invention) Thus, according to the present invention, it is possible to effectively reduce pattern noise and improve the interior comfort of a vehicle interior, with little or no loss of steering stability and road grip required for high-performance tires for passenger cars. After a significant improvement, the occurrence of hydroplaning can be sufficiently prevented.

[Brief explanation of the drawing]

1 and 2 respectively show a tread pattern showing an embodiment of the present invention, and FIG. 3 shows a tread pattern showing a conventional example. 1... Circumferential main groove 2... Circumferential side groove 4.
...First inclined groove 5.8...Block 5a,
3a...Inner sub-block 5b, 8b...Outer sub-block 6.9...Block row 7...Second inclined groove 1
0, 11... Thin groove 12... Rib Figure 1!・−・IW1 direction home feces 2−・・・・−・Rinkata f;I side Ikujun fOΔ1・・・・Tuna Nue

Claims (1)

[Scope of Claims] 1. At least one circumferential main groove extending in the central region of the tread surface, and at least one circumferential main groove located on each side of the circumferential main groove and substantially connected to the circumferential main groove. a pair of circumferential side grooves extending in parallel; a first block extending between the circumferential grooves and between the circumferential side grooves and the tread edge; and a first block near the center of the tread; at least a first inclined groove located across the circumferential main groove, the plurality of first and second inclined grooves partitioning the row and the second row of blocks near the tread end. are separated from each other in a tendency toward the front side toward the rear side in the rotational direction of the tire, the first inclined groove being an inner end portion located close to the circumferential main groove; Each block of the first block row is composed of an outer end portion located close to the circumferential side groove, and an intermediate portion located between these end portions and extending substantially in the circumferential direction of the tire. is a narrow groove that has a groove width such that the groove walls contact each other when the tire is rolling under load, and that interconnects each of the intermediate portions that are adjacent to each other in the circumferential direction of the tire, and is located on the inner and outer sides of the tire width direction. A pneumatic tire characterized by being divided into sub-blocks. 2. The intermediate portion of the first inclined groove and the narrow groove located across the circumferential main groove are separated from each other from the front side to the rear side in the rotational direction of the tire, and the intersection angle between them and the circumferential main groove is 1
2. The pneumatic tire according to claim 1, wherein the pneumatic tire has an angle in the range of 10° to 10°. 3. The pneumatic tire according to claim 1 or 2, wherein the groove width of the inner end portion of the first inclined groove is gradually expanded toward the outer end portion thereof. 4. Claim 1, wherein the inner sub-block is arranged forward in the rotational direction of the tire over a distance of 50 to 20% of the circumferential length of the outer sub-block.
The pneumatic tire according to any one of to 3.