JPH04353003A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To improve comfortability by making the tread width direction inner edge part of one of a pair of inclined grooves overlap with the tread width direction external edge part of the other inclined groove, and continuing it by an N-shaped bent groove to maintain wet performance and reduce pattern noise. CONSTITUTION:Plural pairs of inclined grooves 2, 3 which extend in roughly parallel to each other are provided with the tire equatorial line X-X put between on a tread ground contact part 1, the other inclined groove 2 is made open to the tread edge, and the other inclined groove 3 is extended to the tire equatorial line. Besides, the tread width direction inner edge part of the inclined groove 2 and the tread width direction external edge part of the inclined groove 3 are overlapped with each other in a tread width direction. With this constitution, both the overlapped edge parts are continued by a roughly N-shaped bent groove 4, and the width of both side parts 4a, 4a, of the bent groove 4 is made considerably larger than the width of the respective inclined grooves 2, 3 and a central bent edge part 4b. It is thus possible to reduce pattern noise and improve comfortability.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a pneumatic tire suitable for use in passenger cars, and in particular to a pneumatic tire that effectively improves the interior comfort of a vehicle without impairing wet performance or other general tire performance. It is something.

0002

[Prior Art] As a method of changing the tread pattern to improve the comfort inside the vehicle, each block is made smaller.
In addition to improving the ride comfort of the vehicle, it also disperses pitch noise, reduces the negative rate, reduces the amount of air in the grooves that is a means of noise propagation, and reduces the sound pressure level, and changes the block to ribs. It has been widely known that impact noise can be reduced by smoothing the ground contact.

0003

[Problems to be Solved by the Invention] However, in such prior art, when improving cabin comfort by reducing the size of the block, early wear of the block due to insufficient rigidity of the block and difficulty in maneuverability occur. There is a problem that stability decreases, and if the negative ratio is made small, wet performance decreases, and furthermore, depending on the adoption of the rib pattern, air columns in the grooves continuous in the circumferential direction occur. There was a problem in that high frequency noise was generated due to resonance. This invention was made by focusing on the problems of the prior art, and effectively reduces pattern noise without degrading wet performance, steering stability performance, wear resistance performance, etc., and also reduces vibration. To provide a pneumatic tire that can improve riding comfort.

0004

[Means for Solving the Problems] The pneumatic tire of the present invention has a plurality of pairs of inclined grooves extending substantially parallel to each other in each half of the tread surface, and in each pair of inclined grooves, The inner end portion in the tread width direction of one inclined groove opened at the tread edge and the outer end portion in the tread width direction of the other inclined groove reaching the tread center overlap each other in the tread width direction. and the inner end of one inclined groove and the outer end of the other inclined groove,
Approximately N
The two sides of the N-shaped bent groove extend substantially parallel to the tire equator line, and the central bent side extends along the two slopes. The bent groove extends in a direction opposite to the groove, and the width of both sides of the bent groove is wider than that of each of the inclined grooves and the central bent side. Note that the pattern of the entire tread surface portion may be a so-called point-symmetrical pattern or a directional pattern.

[0005]

[Function] In this pneumatic tire, there are two inclined grooves that form a pair, and the inner end portion of one inclined groove in the tread width direction and the outer end portion of the other inclined groove in the tread width direction By overlapping the grooves over a predetermined length in the direction, it is possible to increase the total volume of the grooves in the overlap area and improve wet drainage performance, and
By opening the one inclined groove at the grounding end,
Reliable discharge to the outside of the tread can be ensured. Furthermore, by making both inclined grooves continuous with each other by an approximately N-shaped bent groove provided in their overlapping portion, the water in those inclined grooves can be smoothly transferred to the low pressure side through the bent groove. This makes it possible for water to flow down to the surface, and sufficient drainage is achieved outside the tread surface.

[0006] Here, the especially wide side portions of the N-shaped bent groove extend substantially parallel to the tire equator line, so that water can be sufficiently drained toward the front side in the rotational direction of the tire. It can effectively prevent the occurrence of hydroplaning by reducing the water pressure in the groove, and also absorb pattern deformation (wiping) in the tread width direction when the tread makes contact with the ground on both sides of the tread. Thus, the ground contact of the tire can be maintained at a sufficiently high level. Moreover, since the central bent side of the N-shaped bent groove is relatively narrow like each inclined groove, it is possible to reduce impact noise. Since the inclination direction of the portion is opposite to that of the inclined groove, it is possible to avoid one-sided flow of the pattern configuration and, by extension, the directionality of the block rigidity, and improve straight-line stability.

Furthermore, by eliminating circumferentially continuous grooves in the entire pattern structure, it is possible to effectively prevent the generation of high frequency noise at a frequency of about 1 KHz due to air column resonance. In addition, here, a pair of inclined grooves and an N-shaped bent groove are used to divide each side of the bent groove into relatively small block portions that are approximately triangular in shape, resulting in milder ground contact. While this improves the ride comfort of the vehicle, by making each triangular block part continuous with the adjacent block part,
Sufficient rigidity of the block as a whole can be ensured, thereby providing excellent wear resistance and handling stability. Thus, according to this tire, it is possible to effectively reduce pattern noise and improve riding comfort while sufficiently maintaining wet performance and other general performance.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 shows a tread pattern showing an embodiment in which the present invention is applied to a so-called point-symmetric pattern. Note that the internal reinforcement structure of the tire is the same as that of a general radial tire, so illustration thereof is omitted here. In this example, the tire equator line X-
A plurality of pairs of two inclined grooves 2 and 3 extending substantially parallel to each other are provided in each half separated by X, and one of the inclined grooves 2 of each pair of inclined grooves 2 and 3 is opened at the tread end. At the same time, the other inclined groove 3 is made to reach the tire equator line XX,
Then, the inner end portion of one inclined groove 2 in the tread width direction and the outer end portion of the other inclined groove 3 in the tread width direction are overlapped in the tread width direction over a predetermined range.

[0009] Here, the inner end of one inclined groove 2 and the outer end of the other inclined groove 3 are formed in an overlapping region of both inclined grooves 2 and 3, so that the overall shape is approximately N-shaped. The bent grooves 4 are made to be continuous with each other by a bent groove 4, and both sides 4a of the bent groove 4 extend substantially parallel to the tire equator line XX, and the central bent side 4b thereof extends substantially parallel to the tire equator line XX. extend in the opposite direction to the respective inclined grooves 2 and 3, and further,
The width of both sides 4a of the bent groove 4 is made sufficiently wider than the width of each inclined groove 2, 3 and the central bent side 4b. By the way, in this example, both the groove widths of inclined grooves 2 and 3 are
The range is 3.0 to 3.5 mm, and the central bent side 4b
Where the groove width of the groove is 2.5 mm, the groove width of both side portions 4a is set to 7.0 mm.

Further, in this example, another inclined groove 5 is formed extending approximately parallel to the inclined groove 2 from the side portion 4a on the tread end side of the N-shaped bent groove 4 toward the tread end side. In addition to setting the groove width of the inclined groove 5 to 5.0 mm, two type 7 grooves with a width of 0.7 mm are provided in each tread half, extending linearly in the circumferential direction of the tire. , an inclined groove 3 extends in each tread half and reaches the tread center, here the tire equator line X-X.
are communicated with each other by another bending groove 8 having substantially the same shape as the N-shaped bending groove 4 described above. According to the pneumatic tire configured in this way, the above-described effects are achieved by the respective actions of the pair of inclined grooves 2 and 3 and the N-shaped bent groove 4, whose groove widths are appropriately selected. In addition, pattern noise can be reduced and ride comfort can be improved without sacrificing wet performance or other general performance of the tire, greatly improving cabin comfort.

FIG. 2 shows an example of application of the present invention to a so-called directional pattern. In this example, each pair of inclined grooves 2 and 3 provided in each tread half is inclined in a direction toward each other on the front side in the rotational direction of the tire, and each pair of inclined grooves 2 and 3 is Each of the tread halves communicates with each other through N-shaped bent grooves 4 facing in opposite directions, and furthermore, in the tread central region 7, each of the inclined grooves 3 reaches from each tread half to the tire equator line XX. The embodiment shown in FIG. 1 is different from the embodiment shown in FIG. 1 in that the tires are communicated with each other by thick grooves 9 extending substantially parallel to the tire equator line XX and alternately offset left and right with respect to the equator line XX. differ. However, also in this example, under the action of the inclined grooves 2, 3 and the N-shaped bent groove 4 that meet predetermined requirements, substantially the same effect as described with respect to FIG. 1 can be brought about.

[Comparative Example] Comparative tests on pattern noise, vibration riding comfort, hydroplaning resistance, steering stability performance, and wear resistance between the invention tire and the conventional tire will be explained below. ◎Invention Tire 1 A tire having the tread pattern shown in Fig. 1 and various groove dimensions, the size is 205/60R15, and the tread surface width is 160 mm. ◎Invention Tire 2 A tire having the tread pattern shown in FIG. 2, with various groove dimensions, sizes, and tread widths similar to those shown in FIG. 1. ◎Comparison Tire A conventional tire having the tread pattern and various groove dimensions shown in Figure 3, with both the size and tread width being the same as the invention tire. ◎Test method The various tires listed above were installed on an actual vehicle, and the tire internal pressure was determined by JI
The normal internal pressure and load conditions specified in S are 2 people on board, and the pattern noise is 1.
By feelingly evaluating the noise inside the vehicle while driving at 00km/h to 40km/h, vibration ride comfort can be evaluated by feeling the ride comfort when driving on various road surfaces such as joint roads and cracked roads. Hydroplaning resistance is determined by measuring the speed at which the hydroplaning phenomenon occurs when driving on a wet road surface with a water depth of 5 mm, and handling stability on a dry road surface is evaluated by feeling through a handling test on a test circuit course. By doing so, the wear resistance is 1.
Each was determined by measuring the amount of wear after traveling 10,000 km. ◎Test Results Table 1 shows the results of each test using index values. Note that the larger the index value, the better the result.

[0013] According to this table, all of the invention tires can effectively improve pattern noise and vibration riding comfort while maintaining sufficiently high hydroplaning resistance, handling stability, and wear resistance. That is clear.

[0014]

Thus, according to the present invention, as is clear from the above comparative test results, the interior comfort of the vehicle interior can be effectively improved without impairing the general performance of the tire.

[Brief explanation of the drawing]

FIG. 1 is a tread pattern showing an embodiment of the invention.

FIG. 2 is a tread pattern showing another embodiment of the invention.

FIG. 3 is a diagram showing a tread pattern of a comparative tire.

[Explanation of symbols]

1 Tread surface 2　One side inclined groove 3　Other inclined groove 4 Bending groove 4a Side part 4b Center bent side 5 Slanted groove 6 Sipe 7 Tread center area

Claims (1)

[Claims] 1. A plurality of pairs of inclined grooves extending substantially parallel to each other are provided in each half of the tread surface, and in each pair of inclined grooves, one of the inclined grooves is opened at the end of the tread. The inner end portion in the tread width direction and the outer end portion in the tread width direction of the other inclined groove that has reached the tread center are positioned so as to overlap each other in the tread width direction, and the inner end portion of the other inclined groove The end and the outer end of the other inclined groove are made to be continuous with each other by a substantially N-shaped bent groove provided in an overlap region of both inclined grooves,
Both sides of this N-shaped bent groove extend substantially parallel to the tire equator line, and its central bent side extends in the opposite direction to the both inclined grooves, A pneumatic tire, wherein the width of both sides of the groove is wider than that of each of the inclined grooves and the central bent side.