JPS61166709A - Low noise level tire - Google Patents

Abstract

PURPOSE:To enable a noise level to be reduced by configurating a tire tread section which has a block form as a basic pattern in such a manner that a basic block line has unit blocks arranged at an interval of an equal pitch, and phase difference block lines have unit blocks arranged so as to be shifted from the basic block line in the circumferential direction. CONSTITUTION:This tire tread section has three block lines: a basic block line A, phase difference block lines B, and C. The basic block line A has each unit block or A1, A2, A3... arranged at an interval of an equal pitch along the tire equatorial plane to the circumferential direction. And the phase difference block lines B and C have each unit block of them arranged inside in such a way that each unit block of the line B and C is shifted to the circumferential direction from each unit block of the basic block line A. In other word, an unit block B1 of the phase difference block line B is shifted by a distance of S in the circumferential direction from the unit block A1 of the basic block line A which is adjacent to the axial direction. Similarly, the unit block B2 and B3 are shifted from the unit block A2 and A3 by the distance of M and L respectively. And the phase of the phase difference block line 3 is shifted in the same manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to motorcycle tires, passenger car tires, and truck and bus tires that reduce noise caused by contact between tires and road surfaces during running.

[Conventional technology]

In general, a tire tread design is configured as a continuous repeating pattern of tread design elements in the circumferential direction of the tire, so the air contained in the grooves of the tire tread is compressed and released as the tire moves. In addition, as a result of the repeated pulse vibrations emitted from the trend design elements due to tire rotation, compression waves are generated in the air in the vicinity, creating pattern noise or impacting sound, which causes so-called noise. , the noise will further increase if it matches the common AM wave number of each part of the vehicle. Traditionally, the method of reducing this type of noise has been to disperse the noise over a wide frequency band and make it less noticeable.
In addition, in order to prevent an increase in noise due to resonance, a barrier pull pitch method is known in which the pitch arrangement, which is the smallest unit of the repeating pattern in the tread design, is improved. This barrier pull pitch method involves arranging tread design elements with different pitch lengths in an appropriate manner around the tire circumferential direction, and reducing the pulse noise or vibration that occurs when each trend design element leaves the ground contact surface. This is a method of changing time intervals to prevent noise from concentrating on specific frequencies, and is based on frequency modulation theory used in radio engineering.

However, even if the pinch arrangement of tread design elements has good dispersion in terms of frequency modulation theory, if the ratio of the length of the longest pitch to the length of the shortest pitch is large, the stiffness of the tread design elements of each pitch will differ. is large, which adversely affects the vibration characteristics during tire transfer and causes uneven wear in the form of tire wear.

Furthermore, it has been found that if the pitch arrangement has a peculiar regularity, the result is extremely unpleasant and bad for the human hearing sense.

[Problem to be solved]

The present invention relates to a low-noise tire that solves the above problems and reduces noise without sacrificing the basic characteristics of the tire tread, such as uneven wear resistance and wear resistance.

[Technical means]

The present invention has a plurality of block rows connected in the tire circumferential direction, and the block rows include a basic block row in which unit blocks are arranged at the same pitch in the tire circumferential direction, and The present invention is a low-noise tire characterized by including a tread pattern consisting of a phase difference block array configured such that the phase is shifted in the direction and the phase shift is different between unit blocks adjacent in the circumferential direction. .

An embodiment of the present invention will be described below based on the drawings.

In Fig. 1, there is a basic block row A in which unit blocks A1, A2, A3, etc. are arranged at the same pitch in the circumferential direction along the tire equatorial plane, and a circumference is provided for each unit block in the basic block row inside the basic block row A. The unit block B1 of the 0-phase difference block row B, in which phase difference block rows B and C consisting of unit blocks whose phases are shifted in the direction, is arranged relative to the unit block 81 of the basic block row A adjacent in the axial direction. The phase is shifted by S in the circumferential direction, and the unit block B2 is out of phase with the unit block A2 of the basic block row A adjacent in the axial direction.
, the phase is shifted by M in the circumferential direction, and unit block B3 is similarly shifted from unit block A of basic block row A.
The 0 phase difference block row C, which is out of phase by L in the circumferential direction with respect to the basic block row A, is also out of phase in the same manner as the relationship between the phase difference block row B and the basic block row A.

Here, the relationship between each phase difference S and MSL is S<M<L,
These three different phase differences form one unit and are repeated periodically or randomly in the circumferential direction.

In the present invention, in addition to three types of phase differences, two or several types can be adopted, and it is also possible to configure phase difference block arrays B and C with different phase differences. The basic block row A is composed of unit blocks having the same pitch, and the pitch here is defined as the sum of the circumferential length la of the unit block An and the circumferential block interval.

It is preferable that the block spacing is larger than the amount of phase difference. Here tire size 4゜60-18
Table 1 shows specific examples where the tires shown in FIG. 1 are used as motorcycle tires.

In Table 1 and Figure 2, there is a basic block row E in which unit blocks E1, E2, E3- are arranged at the same pitch in the circumferential direction along the tire equatorial plane, and each unit block in the basic block row is placed on both sides of the basic block row E. On the other hand, phase difference block rows F and G, which are composed of unit blocks whose phases are shifted in the circumferential direction, are arranged. Unit blocks F1, F2, F of phase difference block array F
3 are unit blocks E1, F2, F3 of basic block sequence E
-, the phases are shifted downward by 81, Ml, and Ll, respectively.

On the other hand, the unit blocks G1, G2, G of the phase difference block array G
3- is the unit block E1 of the basic block sequence E,
The phases are shifted upward by S2, M2, and F2 with respect to F2 and F3-., respectively. In other words, the phase difference block arrays F and G have phases shifted in opposite directions. Examples of 5l-52, Ml-M2, and Ll-F2 are shown here. Table 2 shows specific examples when the tires shown in FIG. 2 are used as motorcycle tires with a tire size of 4.60-18.

Table 2 Motorcycle tires with a tire size of 4.60-18 shown in Table 1 (Example 1) Tires shown in Table 2 (Example 1)
Example 2) and tires shown in FIG. 3 (comparative example) were trial produced. Noise test is air pressure, 75ktf1
JASO, C60 under the conditions of 0j, load 100klrf
In accordance with the tire noise test method stipulated in 6, place the sound collecting microphone directly next to the tire at a distance of 50 CII from the center of the tire width.
The tire was placed at a height of 25all above the ground surface, and measurements were taken while rotating the tire by driving a drum in an anechoic chamber.

Note that the patterns of Example 1, Example 2, and Comparative Example all have unit blocks of the same shape arranged, and only differ in phase.

As shown in FIG. 4, the measurement results of the noise level show that the noise was reduced in all the examples.

〔Effect of the invention〕

As mentioned above, in a tire tread section whose basic pattern is a block shape, by shifting the phase of multiple rows of blocks in the circumferential direction of the tire, synchronization of contact between the blocks and the road surface can be prevented, and the absolute value of the noise level can be reduced. At the same time, it is possible to reduce noise due to frequency dispersion.

[Brief explanation of drawings]

1 and 2 are partial plan views of the tread portion of the tire of the present invention, FIG. 3 is a partial plan view of the tread portion of a conventional tire, and FIG. 4 is a graph showing the relationship between speed and noise level. be. Patent applicant Sumitomo Rubber Industries Co., Ltd. Agent
Patent Attorney Naemura Masatan 1m Figure 2 S3 Procedure Amendment (transfer) July 3, 1985

Claims (3)

[Claims] (1) It has a plurality of block rows that are continuous in the tire circumferential direction,
The block row has a basic block row in which unit blocks are arranged at the same pitch in the tire circumferential direction, and a phase shift in the circumferential direction with respect to the unit blocks of the basic block row, and the phase difference is the same in the circumferential direction. A low-noise tire characterized by including a tread pattern consisting of a phase difference block row configured such that adjacent unit blocks are different from each other. (2) The low-noise tire according to claim 1, wherein the phase difference block array is composed of three types of unit blocks having different phases. (3) The low-noise tire according to claim 1, wherein the circumferential block interval D of the basic block row is larger than the largest phase difference L.