JPH01282006A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To transform a pattern sound into a music from a noize by setting the total number of a lot of chord pitch elements formed on a tread part of a tire in a specified value as well as setting each pattern sound of base ribs and chord ribs in a specific consonant relation. CONSTITUTION:Each rib 4 is formed by a lot of vertical grooves 3 on a tread part 2 of a tire 4 and each base pitch element 6a is formed by a lot of horizontal grooves 5 on a base rib 4a. Each chord pitch element 6b, 6c is also formed by a lot of horizontal grooves 7, 8 on a plurality of chord ribs 4b, 4c. In this case, the total numbers of chord pitch elements 6b, 6c respectively are set in a value obtained by multiplying a value attained by putting a positive integer of 1-24 in the place of n of 2<n/12> by the total number of base pitch elements 6a and raising or omitting the resulting multiplied value. Pattern sounds of each chord ribs 4a are set in n degree of the 12 musical scale higher than a pattern sound of the base ribs 4a to be in a consonant relation with the sound of the base ribs 4a.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) This invention relates to a pneumatic tire with an improved tread pattern.

In the past, various proposals have been made to reduce the noise generated by pneumatic tires; for example, one in which the pitch of the tread pattern is varied in the circumferential direction is known.

This tire has multiple types of circumferential ribs provided on the tread portion of the pneumatic tire, such as A, B, 03
It is composed of pitch groups of different types arranged in a fixed order in the circumferential direction, and each pitch group is composed of at least one pitch element, for example, a block, having the same pitch length. When the pitch of the tread pattern is changed in the circumferential direction in this manner, the order peak frequency components of the impact sound are dispersed, thereby reducing the pattern noise to a considerable extent and turning it into white noise.

However, with such pneumatic tires,
During driving, different types of pitch elements repeatedly hit the road surface in a fixed order, so the magnitude of the input to the pneumatic tire changes over time, and the harmonic frequency of the impact sound generated from any one type of pitch element changes over time. When the frequency component matches the natural frequency of the pneumatic tire, this frequency component is resonantly amplified, but such amplification is repeated every time the pitch element of the above type hits the road surface. Amplitude fluctuations (beats) were occurring in the noise. Moreover, since the noise from such pneumatic tires is a mixture of various noises, it is only audible and unpleasant.

``Such a problem is that the tread part has a basic rib consisting of a large number of basic pitch elements arranged in the circumferential direction, and a chord pitch element with a pinch length different from the basic pitch element. a pneumatic tire comprising: at least one chord rib configured by arranging a large number of chord ribs in the circumferential direction; The product is obtained by multiplying the value obtained by substituting any positive integer by the total number of basic pitch elements, and the integer value obtained by rounding up or down this product, and the pattern sound from the basic rib. When corresponds to any note in the 12-tone scale, the pattern note from the basic rib and the pattern note from the chord rib that is approximately n degrees higher in the 12-tone scale than the pattern note from the basic rib are in a consonant relationship. This can be solved by configuring it so that

In addition, in the pneumatic tire as described above, the chord pitch element is basically composed of blocks defined by a large number of lateral grooves spaced equidistantly apart in the circumferential direction, and the width of each block is W, and the width of each block is When the circumferential pitch is P, and the intersection angle between the tangent to the leading edge on the stepping side at the intersection of the leading edge on the stepping side of the ground contact shape and the widthwise center of the block and the straight line orthogonal to the tire equatorial plane is B, the above-mentioned It is preferable that the inclination angle A of each lateral groove with respect to the orthogonal straight line is determined by the formula (%).

■ In this invention, in the tread part of the pneumatic tire,
A basic rib configured by arranging a large number of basic pitch elements in the circumferential direction, and at least l chord ribs configured by arranging a large number of chord pitch elements having pitch lengths different from the basic pitch elements in the circumferential direction; , and the total chord pitch element of each chord rib is ヮ2.2'x2(7) n : □ka, 924
Yoa. One thing. The product is obtained by multiplying the value obtained by substituting the integer of the pitch element by the total number of basic pitch elements, and this product is rounded up or down to obtain the obtained integer value.

In this way, the basic rib is made up of multiple basic pitch elements of the same type, and the chord rib is also made up of multiple chord pitch elements of the same type, so when traveling, the basic rib and chord rib each have a specific A pattern of different pitches is produced with a peak frequency of , and the peak frequency is proportional to the total number of pitch elements of each rib. Here, the relationship between the total number of basic pitch elements of the basic rib and the total number of chord pitch elements of the chord rib is as described above, that is, the frequency of any note in the 12-tone scale and the note n degrees higher than this note. Since the relationship between the frequency and the frequency of The sound becomes n degrees higher. Furthermore, in this invention, since the pattern sounds from the basic chord ribs are configured to be in a consonant relationship, the sounds generated from each rib are mixed to form a consonant sound, and the pattern sounds from the tires are reduced from noise. It transforms into a musical sound and gives a pleasant feeling to the listener. Moreover, as described above, since each rib is composed of the same type of pitch element, changes in the input to the tire and repeated amplification due to resonance do not occur, and amplitude fluctuations in the pattern sound can be prevented.

Furthermore, as claimed in claim 2, each pitch element is
If we take the inclination angle A of the horizontal grooves that define these blocks to be the value determined by the formula % formula %), we can determine when one part of the block hits the road surface and when another part hits the road surface. The timing coincides with the timing at which both of these impact sounds interfere with each other and cancel each other out, and the sound pressure level of the pattern sound decreases.

Below, a first embodiment of the present invention will be described based on the drawings.

In FIG. 1, 1 is a pneumatic tire, and a tread portion 2 of this pneumatic tire 1 is formed with a plurality of (four in this embodiment) vertical grooves 3 extending in the circumferential direction. The tread portion 2 is defined with a plurality of (five in this embodiment) ribs 4 extending in the circumferential direction. Among these ribs 4, the second rib 4 from the left side is a basic rib 4a, and a large number (48 in this embodiment) of lateral grooves 5 are formed in this basic rib 4a at equal pressure # apart in the circumferential direction. This results in
A large number of basic pinch elements 6a, ie, blocks, having the same circumferential pitch Pa are defined in the basic rib 4a. In this way, the basic ribs 4a are the same type of basic pinch elements 6.
It is constructed by arranging a large number (46 pieces) of a in the circumferential direction. Here, the circumferential pitch P refers to the distance from a reference point of an arbitrary pinch element to a point corresponding to the reference point of a pitch element adjacent to the pitch element. Also, among the ribs 4, the central rib is the 4th or first chord rib 4b,
Further, the second rib 4 from the right side is the second chord rib 4C.

These first and second chord ribs 4b and 4c are also provided with a large number of horizontal grooves 7 and 8, respectively, as described above.
The first chord rib 4b has a large number of first chord pinch elements 6b having the same pitch length pb, and the second chord rib 4C
A large number of second chord pitch elements 6c having the same pitch length Pc are defined. In this way, the first and second chord ribs 4b and 4C are each constructed by arranging a large number of the same type of first and second chord pitch elements 8b and f3c in the circumferential direction. Here, the first chord rib 4b
The total number of chord pitch elements 8b and the total number of second chord pitch elements 8C in the second chord rib 4c are determined by performing the following processing on the total number of basic pitch elements 6a in the basic rib 4a. This is the obtained value. That is, first, the value obtained by substituting any positive integer from 1 to 24 for n of the two threads is multiplied by the total number of basic pitch elements 8a to find the product... 8 degrees. . A, 2 series. □. 3, ka, 824yoa. Hui.

The values obtained by sequentially substituting are listed as 1.06.1゜1
2.1.18.1.26.1.33.1.41.1.5
0.1.58.1゜68.1.78.1.89.2.0
0.2.19.2.22.2.38.2゜52, 2.6
7, 2.83, 3.00, 3°17, 337, 3.5B
, 3°78.4.00, and these values are based on any note in the 12-tone scale, and are 1 degree from the basic note.
It is equal to the value obtained by dividing the frequency of a tone that is one degree higher in a two-tone scale by the frequency of the fundamental tone. That is, the n-th value is equal to the ratio of the frequency of a tone that is n degrees higher than the fundamental tone and the frequency of the fundamental tone. Therefore, for example, if we assume that the value 1.00 is the note C of the 12-tone scale, the above values will be sequentially 12
Scale C#, D, Dll, E, F, Fil, G, G#
, A, A#, and B, respectively. In this example, in order to find the total number of first chord pitch elements 6b, n is set to 4 for the reason described later, and the value obtained by substituting this 4 for n, that is, 1.26, is the total number of basic pitch elements 6a ( 48 pieces) to find the product (57, 96 pieces), and on the other hand, to find the total number of second chord pitch elements 6c, similarly set n to 7, and substitute this 7 for n to find the value obtained. That is, the product (68 pieces) is obtained by multiplying 1.50 by the total number of basic pitch elements 6a (46 pieces). The reason for substituting a positive integer of 24 or less for n as described above is that if the value of n is a positive integer of 25 or more, the total number of chord pitch elements of the chord rib will increase significantly. For example, the pitch length of each chord pitch element becomes extremely short, resulting in adverse effects such as uneven wear. Next, the score is rounded up or down to obtain an integer value, which becomes the total number of chord pitch elements in each chord rib. In this example, the total number of first chord pitch elements 8b is the product (5?,!313 pieces) rounded up to an integer value of 58, while the total number of second chord pitch elements 8c is the product (89 pieces). Since is an integer value, it is left as 68. Here, the reason why the product is rounded up or down as described above is because the number of pitch elements can be less than the decimal point and must be a positive integer.

In this way, the ratio of the total number of basic pitch elements 6a to the total number of first and second chord pitch elements 8b and 6c is approximately 1.00.
: 1.21 (: 1.50, so the peak frequency of the pattern sound generated from the basic rib 4a, first chord rib 4b, and second chord rib 4c during running also becomes this ratio.This means that the basic rib 4a Assuming that the peak frequency of the note corresponds to any note in the 12-tone scale, the note from the first chord rib 4b is n = 4 higher than the note in the 12-tone scale.
This means that the note of the second chord rib 4c corresponds to a note that is n=7 degrees higher than the note in the 12-tone scale. When determining the value to be substituted for the aforementioned n, the tones from the basic rib 4a, the first chord rib 4b, and the second chord rib 4c are set to have a consonant relationship. In this embodiment, as mentioned above, a value of 4 is assigned to n for the first chord rib 4b, and a value of 7 is assigned to n for the second chord rib 4c.
If the note from corresponds to C on the 12-tone scale, then the first
The note from the chord rib 4b approximates E, which is higher than C by n = 4 degrees, and the note from the second chord rib 4c corresponds to G, which is higher by n = 7 degrees than C, and these three pattern tones are part of the chord chord. constitutes a C major consonance. As a result, the pneumatic tire 1, which has the aforementioned basic ribs in the tread portion 2, the first chord rib 4b, and the second chord rib 4c, has a C major chord as a whole when running, and the listener hears the pneumatic tire 1. gives a pleasant feeling. Incidentally, pitch elements are also arranged on the left rib 4d located on the leftmost side of the tread portion 2 and the right rib 4e located on the leftmost side, but these pitch elements may be of any type, for example, the basic pitch mentioned above. , pitch element 8a, first chord pitch element 8b, second
It may be the same as the chord pitch element 8c. There are various types of such consonant relationships in addition to those in the above example. For example, in Appendix 1 (a) and (b), two ribs, that is, a basic rib and a chord rib, have a consonant relationship. The case is shown. Here, we assume that the note from the basic rib is C on the 12-tone scale, and for (a) there is a difference of n = 9 degrees in the 12-tone scale between the basic rib and the chord rib, and for (b), n = There is a difference of 5 degrees. These basic chord ribs can be placed on the tread on both sides of the tire's equatorial plane, or three or more ribs can be provided on the tread, with one of the ribs serving as the basic rib and one of the remaining ribs as the basic rib. You can make the ribs into chord ribs. Also, attached table 2
(a) and (b) have three ribs, namely the basic rib and the first rib.
The second chord rib has a consonant relationship (Cm, C in the chord chord)
5us4) is shown. Again, we assume that the note from the basic rib is C on the 12-tone scale, and (a
), there is a difference of n=3 degrees in the 12-tone scale between the basic rib and the first chord rib, and a difference of n=7 degrees between the basic rib and the second chord rib.
For (b), there is a difference of n = 5 degrees between the basic rib and the first chord rib, and a difference of n = 5 degrees between the basic rib and the second chord rib.
= There is a difference of 7 degrees. In this case, three or more ribs are provided in the tread portion, and one of the ribs is
The book can be used as the basic rib, and any of the remaining ribs can be used as the first and second chord ribs. Furthermore, Table 3 (a) and (b) include four wooden ribs, namely, the basic rib, the first rib, the first rib, the second rib, and so on. A case is shown in which the third chord rib is in a consonant relationship (Cm7, C9 in the chord chord). Here, too, we assume that the note from the basic rib is C on the 12-tone scale, and for (a), there is a difference of n = 3 degrees in the 12-tone scale between the basic rib and the first chord rib, and the second chord rib and the second chord rib. There is a difference of n = 7 degrees between them, a difference of n = 10 degrees between the 3rd chord rep, and a difference of n = 4 degrees between the basic rib and the 1st chord rib for (b). The difference is
There is a difference of n=7 degrees with the second chord rib, and a difference of n=14 degrees with the third chord rib. In this case, if four or more ribs are provided in the tread part, one of the ribs is used as the basic rib, and any of the remaining ribs are used as the first, second, and third chord ribs. good. Note that there are various types of consonant relationships other than those mentioned above, such as A,
D, F, G, Am, Dm, A7, G7, Am7, I)
There are ++7, Cd1m, Caug, and CI'17.

When the pneumatic tire l as described above is run, the basic rib 4a produces a pattern tone whose peak frequency corresponds to, for example, C on the 12-tone scale, and the first chord rib 4b produces a pattern tone corresponding to E.
A pattern sound similar to , and a pattern sound corresponding to G are generated from the second chord rib 4C, and these pattern sounds are mixed to form a C major chord. Therefore, the pattern sound becomes a musical sound, giving a pleasant feeling to the listener. At this time, basic, 1st chord, 2nd chord rib 4
Since a, 4b, and 4c are each composed of the same type of basic, first chord, and second chord pitch elements 6a, 6b, and 6C, uniform input is always given to the pneumatic tire 1, and periodic No significant resonance amplification occurs, and as a result, no amplitude fluctuations (beats) occur.

Next, Test Example 1 will be explained. In this test, a test tire l having a pattern shown in FIG. 1 explained in the first embodiment, a comparative tire having a pattern as shown in FIG. 2,
A third tire with ribs shown in Attached Table 2(a) provided on the tread portion
Test tires 2 as shown in the figure were prepared, and the size of each tire was 205/80R15. Here, the leftmost and leftmost ribs of the test tire 1.2 and the comparative tire are not provided with a lateral groove, and as a result, there are no pitch elements (blocks) in these ribs.

In addition, the comparison tire is a zero-order tire in which the same pitch elements as the basic pitch element 6a, the first chord pitch element 6b, and the second chord pitch element 6C are repeatedly arranged in the above order on three ribs closer to the center. , each such tire has +0
A pattern of sound when traveling at 0 km/hour was generated through simulation, and these sounds were compared.

As a result, the pattern sound of the test tire 1.2 was extremely stable and sounded more like music.

On the other hand, the comparison tire had a feeling of noisy noise. Furthermore, each of these tires was rotated on a drum at 1100 K/hour, and the pattern sounds generated by each tire were compared and the sound was similar to that described above.

Incidentally, this is also clear from the frequency analysis results of the pattern sounds of the test tire 1, the comparative tire, and the test tire 2 shown in FIGS. 4.5 and 6. That is, in Figures 4 and 6, there are three peaks around 0.7KHz to IKHz, but the frequency ratio of these peaks in Figure 4 is approximately 1.00:1.28:
1.50, and in the one shown in Fig. 6, it is approximately 1.00:1.
+9: 1.50, and these peak tones constitute a consonance.

On the other hand, in the comparison tire, the sound pressure level is almost the same within the frequency range, as shown in FIG. 5, and the sound pressure level is heard as noise. Further, the time waveforms of the simulation sounds of the comparison tire and the test tire 1 are shown in FIG. 7 and FIG. 8, respectively.

As is clear from Figure 7.8, the comparative tires
Although the sound pressure level, that is, the amplitude, fluctuates significantly in response to the repetition of different types of pitch elements, in the test tire I, the amplitude fluctuation is small, and the sound pressure level is low overall.

FIG. 9 is a diagram showing a second embodiment of the invention. In this embodiment, the tread portion 1 of the pneumatic tire 11 is
2 are formed with six longitudinal grooves 13 extending in the circumferential direction, thereby forming seven ribs 1 as a block row in the tread portion 12.
4 is formed. Among these ribs 14, the second rib 14 from the left side is called the basic rib 14a, and the fourth rib 14 is called the basic rib 14a.
The sixth rib 14 is the first and second chord ribs 14b, 1
4c, and these ribs 14a, 14b
, 14c have a large number of lateral grooves 15a equidistantly spaced apart in the circumferential direction.
.
, +4c have multiple chord pitch elements, namely the first and second
They define chord blocks leb and lee, respectively. Here, the basic block 1 constituting the basic rib 14a is
The number of basic blocks 6a is 46 as in the first embodiment, the width Wa of each basic block lea is 24 mIn, and the circumferential pitch P
a is 42.8 ma+. On the other hand, the first chord rib 14b
The number of first chord blocks 16b constituting the basic block 1f3a is the value 1.26 obtained by substituting 4 for n and the basic block 1f3a.
The width wb is 24 mm, and the circumferential pitch pb is 33.8 mm. Further, the number of second chord blocks IBc constituting the second chord rib 14c is 1.5, which is obtained by substituting 7 for n.
0 and the number of basic blocks 16a, the width Wc is 24 mm, and the circumferential pitch Pc is 28.
．． It is 4mm. As a result, the first and second chord ribs 14
The peaks of the pattern tones generated from the basic ribs 14a are approximately n=4 degrees and n=7 degrees higher in the 12-tone scale. Here, assuming that the note from the basic rib 14a corresponds to C of the 12-tone scale, the first and second chord reps 14b, +
The notes starting from 4c almost correspond to E and G on the 12-tone scale, and constitute a C major consonance as in the first embodiment. Further, if the inclination angles of the lateral grooves 15a, +5b, 15c in each of the ribs 14a, 14b, +4c are straight lines orthogonal to the tire equatorial plane 17, that is, with respect to the tire axial direction, are respectively Aa, Ab, and Ac, then these inclination angles Aa ,
Ab and Ac are each equal to the value determined by the following formula. In this formula, W is the width of each block lea, lBb, '16c, and the basic, first chord, and second chord blocks lea, 16b,
At 18c, they are all the same and are 24mm. Further, P is the pitch in the circumferential direction of each block lea, +6b, 16c, and for the basic block 1Ela, Pa=42 and Efmm, as mentioned above, for the first chord block +6b, Pb=33.8mm, and for the second chord block, Pb=33.8mm. ! 8
Regarding c, Pcm is 28.4 mm. Furthermore, S
is any positive integer less than or equal to 3, where 5==
It is 1. The reason why the value of S is set to be 3 or less is because if it is 4 or more, the inclination angle A will be close to 80 degrees, and the driving force and braking force during running will be significantly reduced, making it unusable for practical use. It is. In addition, in the above formula, B represents the front edge 21 of the pneumatic tire 11 on the ground contacting side and any blocks 1f (a, 18b), as shown in FIG.
, 16C (here, the basic block 1t3a is taken as an example) is the intersection angle of the tangent 24 to the front edge 21 on the stepping side and the orthogonal straight line to the tire equatorial plane 17 at the intersection 23 with the widthwise center 22 of the basic block 1t3a (here, the basic block 1t3a is taken as an example); In this example,
Since the ground contact shape is approximately rectangular, B=0 degrees. and,
The above ± tan B is inserted into the above formula in consideration of the influence of the curvature of the leading edge 21 on the pressing side, since the leading edge 21 on the pressing side of the pneumatic tire 11 is generally curved. With this ± tan B, the difference in the timing of depression between the one end of each block 16 in the width direction and the other end in the width direction is corrected. Then, by substituting the above value into the formula, the inclination angle Aa of the lateral grooves 15a, 15b, 15c is determined.
Ab and Ac are 60.8 degrees and 54 degrees, respectively.
6 degrees, 48.8 degrees. In addition, the horizontal groove 15a,
The inclination directions of 15b and +5c are the same in the basic rib 14a and the second chord rib 14c, and are opposite in the first chord rib 14b.

Then, when the pneumatic tire 11 as described above is run, each rib 14a, +4b of the pneumatic tire 11
The pattern sound generated from , 14c becomes a C major chord as a whole, giving a pleasant feeling to the listener, and the timing when a certain part of each block lea, IElb, IBc hits the road surface, and the other part hits the road surface. The timing coincides with the timing at which both of these impact sounds interfere with each other and cancel each other out, and the sound pressure level of the entire pattern sound decreases.

Next, Test Example 2 will be explained. In this test, a test tire 3 having a pattern shown in FIG. 9 explained in the second embodiment and a test tire 4 having a pattern shown in FIG. 11 were used.
I prepared these tires, but the size of each tire was 20.
5/80R+5, and its circumference was 1980 mm. Here, the test tire 4 has lateral grooves 15a and 15b.
, 15c is the same as the test tire 3 except that the inclination angle A of 15c is uniformly set to 30 degrees.

Note that this angle of inclination A=30 degrees is different from the value obtained using the above formula. Next, such a test tire 3.4 was run on a drum, and the sound pressure level of the generated noise was measured at each speed. The results are shown in Figure 12.
As is clear from Figure 2, test tire 3 was faster than test tire 4 over the entire speed range (40 km/hour to 1100 km/hour).
The sound pressure level is decreasing. Moreover, the total average value of the sound pressure level in the entire speed range was 73.8d for test tire 3.
B, and on the other hand, test tire 4 was 75. l]dB, and test tire 3 was able to reduce the sound pressure level by 2.1 dB. In addition, such test tire 3
．． After installing Tire 4 in a passenger car, a driver conducted a noise feeling test by driving on a good road at 50 km/hour.If the index of test tire 4 was 100, the index of tire 3 was 110. Test tire 3 was also good in terms of rings. This feeling was particularly good at speeds of 60 km/hour or less.

In the above-mentioned embodiment, the basic chord rib was composed of one wooden rib, but in this invention, two or three adjacent wooden ribs are grouped together to form one wooden basic chord rib. may be configured.

As described above, according to the present invention, it is possible to change the pattern sound from noise to musical sound, and it is also possible to reduce the amplitude fluctuation of the pattern sound.

[Brief explanation of the drawing]

Fig. 1 is a partially exploded view of the tread portion of the first embodiment of the present invention, Fig. 2 is a partially exploded view of the tread portion of the comparative tire used in Test I, and Fig. 3 is a partially developed view of the tread portion of the comparative tire used in Test I. A partially exploded view of the tread section of test tire 2, Figure 4 is test tire 1
Graph showing the frequency analysis results of pattern sounds from 5th
The figure is a graph showing the frequency analysis results of the pattern sound from the comparison tire, Figure 6 is a graph showing the frequency analysis result of the pattern sound from test tire 2, and Figure 7 is the time waveform of the simulation sound from the comparison tire. 8 is a graph showing the temporal waveform of the simulated sound from the test tire 1, FIG. 9 is a partially exploded view of the tread section showing the second embodiment of the present invention, and FIG. Fig. 11 is a partial exploded view of the tread part of test tire 4 used in test 2, and Fig. 12 is a diagram showing the contact shape of the tread part used to explain test tire 3.4. It is a graph which shows the measurement result of a noise sound pressure level. 1.11... Pneumatic tire 2.12... Tread portions 4a, 14a... Basic ribs (block rows) 4b, 4c
, 14b, 14c ・-Chord rib (block row) 6
a, lea...basic pitch element (block) 6b, 6
c, 16b, 18cm chord pitch element (block) 15a, 15b, 15c---Horizontal groove 17...
・Tire equatorial plane 21...Leading side leading edge 22...
・Width direction center 23...Intersection point 24...Tangential line
L...Orthogonal straight line Patent applicant Brideston Co., Ltd. Agent Patent attorney Tadashi 1) Toshio - Katada Δ゛ (Shinonome N ward - C'J ＼r co z ward Figure 5 frequency (KH2) - th Figure 7 Time (seconds) □ Figure 6 Frequency (KH2) - Figure 8 Time (seconds) -

Claims (2)

[Claims] (1) The tread portion includes a basic rib configured by arranging a large number of basic pitch elements in the circumferential direction, and at least a basic rib configured by arranging a large number of chord pitch elements having pitch lengths different from the basic pitch elements in the circumferential direction. A pneumatic tire comprising one chord rib, where the total number of chord pitch elements of each chord rib is set to n of 2^n^/^1^2 by any positive number from 1 to 24. Multiply the value obtained by substituting an integer by the total number of basic pitch elements to obtain a product, round up or down this product to obtain an integer value, and set the pattern note from the basic rib to any of the 12 scales. When made to correspond to the above note, the pattern note from the basic rib and the pattern note from the chord rib that is approximately n degrees higher in the 12-tone scale than the pattern note from the basic rib are configured so as to have a consonant relationship. A pneumatic tire characterized by: (2) The basic chord pitch element is composed of blocks defined by a large number of horizontal grooves spaced apart at equal distances in the circumferential direction,
And, the width of each block is W, the circumferential pitch of each block is P, a positive integer of 3 or less is s, and the stepping side at the intersection of the stepping side front end of the ground contact shape and the center of the block in the width direction When the intersection angle between the tangent to the leading edge and the orthogonal line to the tire equatorial plane is B, the inclination angle A of each lateral groove with respect to the orthogonal line is the value obtained by the formula tan^-^1 (sP/W ± tanB). A pneumatic tire according to claim 1.