JPH07205616A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To obtain pleasant pattern noises, by synthesizing sounds generated in a tire on traveling as a melody composed of harmonized chords. CONSTITUTION:A plurality of circumferential grooves 4 dividing the grounding face into at least three faces are provided on the tread face 2 and lateral grooves 5A-5C are arranged to cross with the circumferential grooves 4 in the three grounding faces at least. In this way, a row of blocks is formed so that block with a plurality of circumferential lengths Li including blocks with the shortest circumferential length L1 and the longest circumferential length Ln are arranged. When the circumferential lengths are arranged from the shortest one to the longest one in order, the ratio of Li, Li+1, (Li+1/Li), is made to coincide with the frequency ratio of musical scale and further, the musical scales are arranged to make a melody in respective grounding faces and the musical scales are arranged to make harmonic chords in the blocks of the grounding zones arranged axially in the tire.

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 pattern capable of making a pattern noise a pleasant sound by giving a scale to a sound produced when the tire runs and providing a melody.

[0002]

2. Description of the Related Art A tire used for a vehicle such as an automobile or a motorcycle has a tread pattern having a circumferential groove and a lateral groove intersecting with the circumferential direction on a tread surface in order to improve grip and drainage. Many.

In a tire having a large number of such lateral grooves, when compressed, air compressed between the tread surface and the road surface suddenly flows out to the outside through the grooves, and this occurs intermittently. The noise is called a pumping noise and is dissipated, and such noise often occurs in a tread pattern in which a large number of lateral grooves are provided in the circumferential direction.

[0004]

In order to suppress such noise, measures are taken such as reducing the cross-sectional area of the lateral groove or bending the lateral groove to reduce the flow velocity of air passing through the groove. There are also the same. However, although the noise of these tires is slightly reduced, the grip performance is reduced,
There is a problem that running performance and durability of the tire are deteriorated due to occurrence of uneven wear.

The inventor has found that the above-mentioned harsh noise can be made pleasant by making the noise passing through the tire pleasant by making it a sound having a melody as the tire runs, and the pattern can be easily formed. The invention was completed.

According to the present invention, the ground contact surface of the tread portion is divided into at least three contact areas, and the circumferential length of the block formed by the lateral grooves arranged in each contact area is related to the frequency ratio forming the melody. Basically, it is intended to provide a pneumatic tire that can make the noise of the tire comfortable while running.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a plurality of circumferential grooves are provided on a tread surface of a tire to divide a ground contact surface into at least three contact areas, and the circumferential grooves are provided in the at least three contact areas. By arranging the lateral grooves that intersect with the direction grooves, a block row in which a plurality of types of blocks having the circumferential length Li and a block having the shortest circumferential length L1 and a block having the longest circumferential length Ln are arranged side by side is arranged. The ratio (Li + ₁ ) / Li of the circumferential lengths Li and Li + _{1, which} are formed respectively and arranged in order from the shortest circumferential length L ₁ to the length, is the frequency ratio of the scale and one In the area, the pneumatic tires are characterized in that the scales are arranged in a melody and the blocks in the contact areas arranged in the tire axial direction are arranged in a consonant chord.

Here, so-called pattern noise generated from the tire pattern, when the peripheral speed of the ground contact surface is Smm / sec. And the circumferential length of the block is Lmm, the primary frequency f of the sound is (S / L). It becomes Hz.

That is, the frequency of noise also changes depending on the frequency length L of the block. As the circumferential length L of the block increases, the frequency f also increases.

In the present invention, the noise is tuned by sequentially changing the circumferential length L of blocks which are continuous in the circumferential direction.

Here, the melody is a series of sounds that are accompanied by a change in pitch, which are continuous, and further include a combination of the pitch and the rhythm of the sound.

Further, a consonant chord is a sound in which three sounds that are emitted at the same time are superimposed, and for example, a long triad or a short chord such as (do, mi, so), (do, fa, la) and (shi, le, so). Includes 3 chords.

[0013]

[Function] Regarding the circumferential length of each block forming the block row, the ratio of the circumferential length of the block is (Li + ₁ ) /
Li is the frequency ratio of the scale. As a result, the noise generated by the mechanism, that is, the so-called pumping sound, changes continuously with the running when the vehicle is running, so that the sound emitted from the tire continuously has a scaled sound.

Further, in one contact area, since the scales are arranged in a melody, the sound generated by the running of the tire becomes a pleasant sound that induces a pleasant sensation.

It is to be noted that, in one contact area, a plurality of pieces having the same circumferential length are appropriately arranged adjacent to each other, for example, by arranging as Li- ₁ , Li, Li, Li + _1, a short sound and a long sound are produced. It becomes possible to express the melody as a melody by mixing and.

In addition, since the blocks in the contact area arranged in the axial direction of the tire are arranged so that the scales form consonant chords, the sound emitted from the tire becomes a melody of the chords, which further enhances the pleasant feeling.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1, 2 and 4, a pneumatic tire 1 includes a tread portion 12 forming a tread surface 2 and a pair of sidewall portions 13 extending inward in the tire radial direction from both sides thereof,
13 and a bead portion 14 extending inward of the sidewall portion 13.

The pneumatic tire 1 has a tread portion 12
A carcass 16 that folds around the bead core 15 of the bead portion 14 from the inner side to the outer side in the tire axial direction from the side wall portion 13, and a belt layer 17 disposed outside the carcass 16 and inside the tread portion. And with.

In this embodiment, a bead apex 18 made of rubber having a triangular cross section and made of hard rubber is erected radially outward of the bead core 15 and between the main body of the carcass 16 and the folded portion.

In this example, the carcass 16 is made of one carcass ply, and the carcass ply is made of nylon,
Carcass cords made of organic fibers such as polyester, rayon, and aromatic polyamide are attached to the tire equator C at 7
It is formed as a radial or semi-radial arrangement juxtaposed at an angle of 5 to 90 °.

In this embodiment, the belt layer 17 is composed of two belt plies, and each belt ply has a belt cord made of an organic fiber such as nylon, rayon, aromatic polyamide, or a steel cord with respect to the tire equator C. 1
It consists of cut plies arranged at an angle of 0 to 70 °. The belt cords are arranged so as to intersect with each other between the belt plies.

On the tread surface 2, there is a grounding surface 3 on which the tread surface 2 comes into contact with the ground in a normal state where a normal internal pressure and a normal load are applied to the tire. At least three contact areas, that is, the first contact area 3A located on the tire equator C in this embodiment, is formed by the at least two circumferential grooves 4 and 4 which circulate the contact surface 3 in the tire circumferential direction. A second contact area 3B and a third contact area 3C, which are arranged on both sides in the tire axial direction of the first contact area 3A and with the circumferential groove 4 therebetween.
It is divided into three contact areas with.

These first, second and third contact areas 3A,
In 3B and 3C, in the direction intersecting with the circumferential grooves 4 and 4,
Also, in each contact area 3A, 3B, 3C, a first lateral groove 5A extending in a direction intersecting the circumferential direction, a second lateral groove 5
B, and third lateral grooves 5C are provided.

As a result, in the first contact area 3A, the first blocks B1 are arranged in the circumferential direction in the first block row B1.
L is a second block row B2L in which the second blocks B2 ... Are arranged in the circumferential direction in the second contact area 3B, and a third block B3 ... is in the circumferential direction in the third contact area 3C. Lined up in the third
The block row B3L of is formed.

In the present embodiment, the first contact area 3A includes the tire equator C, and therefore has the highest ground contact pressure among the ground contact surfaces 3. In the first contact area 3A, the blocks B1 are formed with different circumferential lengths L of the blocks B1, that is, different pitches between the lateral grooves 5A, 5A.

[0026] The first of the block column B1L shortest circumferential length L ₁ of the blocks B1 ₁ and the longest circumferential length Ln
The plurality of kinds of circumferential lengths Li including the block Bln are arranged.

Further, in the first block row B1L, the circumferential length Li is arranged from the shortest circumferential length P1.
The ratio (Li + ₁ ) / Li between Li and Li + ₁ is the frequency ratio of the scale.

A section in which the frequency of sound is doubled is defined as one octave, and if this one octave is divided into twelve scales, the frequency ratio x of one scale is expressed by the equation (1). x = 2 ^1/12 = 1.0595 (1) As a result, the frequency ratios of other scales are shown in Table 1 based on the (d) of music.

[0029]

[Table 1]

In this embodiment, the case where the melody shown in FIG. 3 is used for a pattern will be described as an example. When a series of melody as shown in Table 2 is used as a basic scale, the pitch ratio and the ratio of adjacent pitches are shown in Table 2.

On the other hand, when the circumferential speed of the ground contact surface 3 is S mm / sec and the circumferential length of the block B1 is L, the primary frequency f of the sound of the tire pattern sound is (S /
L) Hz. Therefore, the shorter the circumferential length L of the block, the higher the frequency of the sound, that is, the higher the sound.

Therefore, the circumferential length ratio (Ln + m) / between the adjacent blocks B1 and B1 according to the inverse ratio of the adjacent pitch ratio.
By setting Ln, the pattern sound can have a scale, that is, a melody-like sound can be emitted as the tire rotates.

Further, adjacent blocks B1 and B1 in the first block row B1L have the same circumferential lengths Ln and L.
By arranging a plurality of blocks having n side by side,
A long sound can be formed, and a more melodious sound can be generated.

As the melody adopted as the tread pattern, in addition to the melody played by instrumental music, a melody of so-called electronic music synthesized by an electronic device can be adopted.

On the other hand, the first, second and third contact areas 3A,
Between 3B and 3C, blocks B lined up in the tire axial direction
The circumferential lengths of 1, B2 and B3 are made different, and these circumferential lengths are associated with the frequency of the consonant chord.

Sounds that we hear every day are heard as superposed sounds in which a plurality of sounds having different frequencies are emitted at the same time except for some special sounds such as tuning fork sounds. Further, when the frequencies of the two sounds are close to each other, a resonance sound (beat) is generated and an unpleasant sound is generated. Of these superposed sounds, those that give a pleasant sensation to people are defined as consonant chords, and those that cause discomfort are defined as dissonant chords.

In the interval between the three sounds on which the consonance chords are superposed, there is a certain ratio of the frequencies of those sounds.

Therefore, the frequency ratio (f _A : f _B : f _C ) of the consonant chord consisting of three tones is, for example, 1: 2 ^4/12 : 2 ^7/17 in (do, mi, so). In (So, Si, Re), it becomes 1: 2 ^5/12 : 2 ^8/12 .

In FIG. 2, the first contact area 3A is the main melody sound, and the first contact area 3A is the remaining second
Together with the third contact areas 3B and 3C, they form a consonant chord. That is, the first, second, and third contact areas 3A, 3B, 3C
The ratio (1 / Ln: 1 / Lr: 1 / Ls) of the reciprocals of the respective circumferential lengths Ln, Lr, and Ls of (1) is made equal to the frequency ratio (f _A : f _B : f _C ). .

As a result, by setting 1 / Ln: 1 / Lr: 1 / Ls = 1: 2 ^4/12 : 2 ^7/17 , a sound composed of harmonic chords (do, mi, and so) is produced, and 1 / Ln: 1 /
Ln: 1 / Lr = 1: 2 ^4/12 : 2 ^2/12 , (So,
Harmonic chords are produced.

As described above, it is possible to generate a melody sound composed of consonant chords shown in FIG. 5 on the ground contact surface 3.

Further, in this embodiment, the second and third contact areas 3B and 3C arranged on both sides are positioned so that adjacent tones are produced among the chords. As a result, the pitch difference between the second and third lateral grooves 5B and 5C is reduced, and the tread surface 2
This is because the asymmetry in the axial direction at is relaxed and the one-sided flow of the vehicle can be suppressed.

[0043]

As described above, the pneumatic tire of the present invention is
With the above configuration, the sound generated by the pattern during traveling becomes a melody consisting of harmonic chords, becomes a pleasant sound, is transmitted to the driver, and the fatigue of the driver and people outside the vehicle can be reduced. Moreover, since the tread pattern can be easily formed, the tire can be economically produced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a tread surface thereof.

FIG. 3 is a staff notation showing a melody adopted for a tire.

FIG. 4 is a plan view showing a tread pattern on the ground contact surface.

FIG. 5 is a staff notation showing a melody based on the consonant chords.

[Explanation of symbols]

 2 tread surface 3 ground plane 3A, 3B, 3C contact area 4 circumferential groove 5 lateral groove 5A first lateral groove 5B second lateral groove 5C third lateral groove L1 ... Ln ... Li circumferential length

[Table 2]

Claims (1)

[Claims] 1. A tread surface of a tire is provided with a plurality of circumferential grooves that divide a ground contact surface into at least three contact areas, and lateral grooves that intersect with the circumferential grooves are provided in the at least three contact areas. By arranging the blocks, a block row having a plurality of kinds of circumferential lengths Li including a block having the shortest circumferential length L _{1 and} a block having the longest circumferential length Ln is formed, and the shortest row is formed. The ratio (Li + ₁ ) / Li of the circumferential lengths Li and Li + ₁ arranged in the order from the circumferential length L ₁ to the length is the frequency ratio of the scale, and in one contact area, the scale has a melody. Pneumatic tire characterized in that the blocks in the contact area arranged in the tire axial direction are arranged in a consonant chord.