JPH11217007A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a columnar resonance sound, while maintaining hydroplaining preventive performance. SOLUTION: In a pneumatic tire provided with a plurality of main grooves 2 extending in the circumferential direction of a tire on a tread 1, a plurality of partitions 3 intercepting the main grooves 2 are provided on at least one of the main grooves 2. To the outer peripheral length of a tire E and the grounding length C, the installation number N of the partitions 3 on whole tread surface is specified in relation of N>=E/C, and the installation space S of the partitions 3 on one main groove 2 is specified in relation of S>=C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire having a tread provided with a main groove extending in a circumferential direction of the tire, and more particularly to a pneumatic tire for reducing air column resonance while maintaining hydroplaning prevention performance. Related to pneumatic tires.

[0002]

2. Description of the Related Art Conventionally, in a pneumatic tire, a plurality of main grooves extending in the circumferential direction of a tire are provided in a tread, and a running performance on a wet road surface, particularly a hydroplaning prevention performance is improved by a drainage effect of the main grooves. ing. However, since the main groove extending in the tire circumferential direction forms an air column between the road surface and the tread, a large noise is generated by the air column resonance sound.

[0003] Therefore, it is common practice to suppress the generation of noise due to air column resonance by bending the main groove in the tire width direction or bending it in a zigzag shape. However, when the main groove is extremely curved or bent, although the air column resonance can be reduced, there is a problem that the hydroplaning prevention performance is reduced. Also,
Japanese Unexamined Patent Publication No. Hei 3-276802 proposes providing an elastically deformable fin in a main groove in order to reduce a noise level without deteriorating wet performance. However, in the above structure, the fins in the main groove are elastically deformed so as to secure a drainage channel when traveling on a wet road surface, so that the air column cannot be completely shut off even when traveling on a dry road surface, resulting in air column resonance noise. The effect of reducing the amount was insufficient.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire capable of reducing air column resonance while maintaining hydroplaning prevention performance.

[0005]

According to the present invention, there is provided a pneumatic tire having at least one main groove provided on a tread having a plurality of main grooves extending in a tire circumferential direction. Are provided with a plurality of partitions for blocking the main groove, and the number N of the partitions on the entire tread is set to N ≧ E with respect to the tire outer peripheral length E and the ground contact length C.
/ C, and the installation interval S of the partition portion in one main groove is set to a relationship of S ≧ C.

As described above, at least one main groove is provided with a plurality of partitions for blocking the main groove, and the number N of partitions installed on the entire surface of the tread and the installation interval S of the partitions in one main groove are determined by the tire. By specifying based on the outer peripheral length E and the ground contact length C, it is possible to effectively reduce the air column resonance sound and suppress the generation of noise while maintaining the hydroplaning prevention performance, by effectively separating the main groove. Can be.

[0007] In the present invention, the tread contact length is defined as a tire pressure filled with an air pressure corresponding to the maximum load capacity in the air pressure-load capacity correspondence table defined in JATMA (1997 version). This is the maximum contact length in the tire circumferential direction when a load of 80% of the capacity is applied.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 illustrates a tread pattern of a pneumatic tire according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a main groove portion provided with a partition portion. In the figure, a tread 1 is provided with a plurality of main grooves 2 extending in the tire circumferential direction. The main groove 2 is provided with a plurality of partitions 3 so as to completely block the main groove 2 up to the surface of the tread 1. Although the partition part 3 needs to be provided in at least one main groove 2, it may be provided in all the main grooves 2. Further, it is preferable that the partitions 3 are arranged at equal intervals in the tire circumferential direction.

As shown in FIG. 2, the radial height H of the partition 3 from the groove bottom is the same as the depth of the main groove 2. By setting the height H of the partition portion 3 in the tire radial direction to be equal to the depth of the main groove 2, the air column in the main groove 2 can be completely shut off. The tire circumferential length L of the partition 3 is 0.3H ≦ L ≦ 1.
It is set so as to satisfy the relationship of 2H. By setting the length L in the tire circumferential direction of the partition portion 3 to 0.3H or more, breakage such as cracks during running can be prevented, and by setting the length to 1.2H or less, the influence on drainage is minimized. Can be suppressed.

The installation number N (N: integer) of the partitioning portions 3 on the entire surface of the tread is set so as to satisfy the relationship of N ≧ E / C with respect to the tire outer peripheral length E and the contact length C. As described above, by increasing the number N of the partition portions 3 provided on the entire surface of the tread to a ratio E / C of the tire outer peripheral length E to the ground contact length C or more, the partition portions 3 can always be arranged in the ground contact surface. Therefore, it is possible to reduce the air column resonance and suppress the generation of noise.

The spacing S between the partitions 3 in one main groove 2 is set so as to satisfy the relationship of S ≧ C with respect to the ground contact length C. By setting the installation interval S of the partition portions 3 in one main groove 2 to be equal to or longer than the grounding length C, two or more partitioning portions 3 do not exist in each main groove 2 in the grounding surface. Since a closed space is not formed in the main groove 2 by the partition portion 3, the drainage function of the main groove 2 is not substantially impaired, and a decrease in the hydroplaning prevention function can be minimized.

The upper limit of the number N of partitions 3 and the upper limit of the interval S are necessarily determined by the relative relationship between the number N and the interval S. For example, if the number of the main grooves 2 in which the partition portions 3 are provided is X, the range of the number of installations N is E / C to X (E
/ C), and the upper limit of the installation interval S is determined by how the selected installation number N is distributed to the X main grooves 2.

According to the present invention, as described above, at least one main groove 2 is provided with a plurality of partitions 3, and the number N of the partitions 3 on the entire surface of the tread and the partitions 3 in one main groove 2 are provided. The installation interval S between the tire circumference E and the contact length C
Thus, the air column resonance can be reduced and the generation of noise can be suppressed while maintaining the hydroplaning prevention performance.

In the present invention, since the columnar resonance is reduced by providing the partition portion 3 in the main groove 2, the main groove 2 is provided.
Can be arranged linearly with emphasis on hydroplaning prevention performance. However, the main groove 2 does not necessarily have to be straight, but may be slightly curved or bent as shown in the figure. Further, the present invention can be applied to the case where a plurality of main grooves 2 extending in the tire circumferential direction are provided in the tread 1, and the tread pattern is not particularly limited, and is applicable to a block pattern and the like. can do.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A conventional tire having a tire size of 205 / 50R16 and a tread having three main grooves extending in the tire circumferential direction as shown in FIG. A comparison tire in which a plurality of partitions are provided at substantially equal intervals in the tire circumferential direction in three main grooves, and the number N of partitions installed on the entire tread and the installation interval S of the partitions in one main groove are variously changed. 1,2
And the tires 1 to 4 of the present invention were produced.

Since the tire outer peripheral length E is 1916 mm and the ground contact length C is 130 mm, N ≧ 15 in the tires 1 to 4 of the present invention. The installation interval S is 13
The length is set to 0 mm or more, and is appropriately set based on the installation number N. For these test tires, the hydroplaning prevention performance and the noise performance were evaluated by the following test methods, and the results are shown in Table 1.

Hydroplaning prevention performance: A test tire was mounted on a passenger car at an air pressure of 220 kPa, and a critical speed until a hydroplaning phenomenon occurred on a wet road surface was measured. The evaluation result was 10
The index was set to 0. The larger the index value, the better the hydroplaning prevention performance. Even if the hydroplaning prevention performance is reduced, there is no practical problem as long as it is within -5% of the conventional tire.

Noise performance: Test tires with air pressure of 220 kP
Installed on a car as a, speed 50k on dry road surface
The vehicle traveled at m / h, and the noise level (dB) was measured at a position 7.5 m away from the traveling road. The evaluation results were obtained by using a measured value of a conventional tire as a reference value and a difference from the reference value.

[0019]

[Table 1]

As is clear from Table 1, the tires 1 to 4 of the present invention were able to greatly reduce the noise level as compared with the conventional tires while maintaining the hydroplaning prevention performance sufficiently. On the other hand, in the comparative tire 1, the reduction in the noise level was insufficient at 1.0 dB or less because the number N of the partition portions was small. Also, comparative tire 2
Since the number N of the partitions was large, the hydroplaning prevention performance was reduced by 5% or more as compared with the conventional tire.

[0021]

As described above, according to the present invention, in a pneumatic tire provided with a plurality of main grooves extending in the tire circumferential direction on a tread, at least one main groove blocks the plurality of main grooves. , The number N of the partitions on the entire surface of the tread is set to a relation of N ≧ E / C with respect to the tire outer peripheral length E and the contact length C, and the partition is installed in one main groove. By setting the interval S to satisfy the relationship of S ≧ C, it is possible to suppress the generation of noise by effectively reducing the air column resonance sound by the partition portion that blocks the main groove while maintaining the hydroplaning prevention performance. .

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a tread pattern of a pneumatic tire according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective sectional view showing a main groove portion provided with a partition portion in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tread 2 Main groove 3 Partition part H Tire radial height of partition part L Tire circumferential length of partition part E Tire outer peripheral length C Contact length

Claims (2)

[Claims] 1. A pneumatic tire having a plurality of main grooves extending in a tire circumferential direction in a tread.
A plurality of partition portions for blocking the main grooves are provided in the main groove, and the number N of the partition portions on the entire tread is set to a relationship of N ≧ E / C with respect to the tire outer peripheral length E and the ground contact length C,
And the installation interval S of the partition portion in one main groove is S
A pneumatic tire having a relationship of ≧ C. 2. The height H in the tire radial direction from the groove bottom of the partition portion is made the same as the depth of the main groove, and the length L in the tire circumferential direction is in a relationship of 0.3H ≦ L ≦ 1.2H. Claim 1
A pneumatic tire according to claim 1.