JP2012096666A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire which achieves both of suppression of pattern noise and improvement in heel-and-toe wear resistance.SOLUTION: In the pneumatic tire provided with a plurality of circumferential grooves 20, 22, a tread pattern 10 dispersedly arranged in the circumferential direction of the tire by first pitch alignment is formed on the inner side of a vehicle relative to the circumferential groove 20 arranged on the innermost side of the vehicle, and the tread pattern 10 dispersedly arranged in the circumferential direction of the tire by second pitch alignment is formed on the outer side of the vehicle relative to the circumferential groove 20 arranged on the outermost side of the vehicle. The first pitch alignment is the pitch alignment in which pitch kinds adjacent to each other in the circumferential direction of the tire are the mutually same pitch kind or the adjacent pitch kinds. The second pitch alignment is the pitch alignment in which the part where the pitch kind other than the adjacent pitch kinds adjoins in the circumferential direction of the tire, and the number of continued pitch kinds having the shortest pitch kinds of the plurality of pitch kinds is three at most.

Description

  The present invention relates to a pneumatic tire provided with a plurality of circumferential grooves extending in the tire circumferential direction.

Conventionally, a pneumatic tire having a tread pattern is provided with a pitch variation in which the pitch length of the pattern is dispersed in the tire circumferential direction in order to reduce pattern noise. Pitch variation is to distribute the pattern noise frequency by distributing the pitch length on the tire circumference so that the level of pattern noise at a specific frequency does not increase when the tire rolls on the ground. .
In the pitch variation, since there is a large degree of freedom in how to distribute the pitch length, pneumatic tires to which various pitch variations are applied have been proposed.

  For example, a tread pattern of a tire tread is formed by a pattern constituent unit row in which three or more types of pattern constituent units having different pitches P, which are circumferential lengths, are arranged in the tire peripheral direction. A pattern constituent unit sequence including a pattern constituent unit sequence arranged to include one or more adjacent pitches arranged in order, and having a predetermined pattern constituent unit sequence obtained by performing a predetermined test. Pitch variation pneumatic tires are known (Patent Document 1).

There is also known a pneumatic tire for making it possible to achieve both improvement in steering stability on a dry road surface and reduction in pattern noise (Patent Document 2).
That is, in the pneumatic tire in which the tire front and back mounting directions with respect to the vehicle are designated, a plurality of tires arranged in the tire circumferential direction in the vehicle inner side (IN) and the vehicle outer side (OUT) with the tire equator E of the tread therebetween. The block elements on the inner side of the vehicle have a pitch number of 60 to 80, the number of types of block elements on the inner side of the vehicle is four or more, and the pitch number of block elements on the outer side of the vehicle is 50 to 70. The number of pitch types of the block elements outside the vehicle is four or more. Further, the pitch number of the block elements inside the vehicle is made larger than the pitch number of the block elements outside the vehicle, and the ratio of the average pitch length of the block elements outside the vehicle to the average pitch length of the block elements inside the vehicle is 1.05. The range is ˜1.20.

JP 2001-130226 A JP 2009-262874 A

  In the pneumatic tire described in the above-mentioned patent document 1, since it arranges including the pattern constituent units arranged by skipping one or more adjacent pitches in the order of the length, the shortest pitch having the shortest length is aligned. It is possible to prevent the block rigidity of the tread from becoming small. For this reason, according to the said pneumatic tire, generation | occurrence | production of pattern noise can be suppressed. However, since it is arranged to include one or more pattern constituent units that are arranged adjacent to each other in the order of the length, there is a portion where the change in the adjacent pitch length is large in the tire circumferential direction, and heel-and-toe wear occurs. Likely to happen.

In the pneumatic tire described in the above-mentioned Patent Document 2, it is possible to achieve both improvement in steering stability on a dry road surface and reduction in pattern noise, but improvement in heel and toe wear resistance performance. Nothing is mentioned.
In particular, in recent vehicles, a pneumatic tire is attached to the vehicle with a negative camber in order to ensure running stability during high-speed running. In such a vehicle, a larger load is applied to the inner portion of the vehicle where the tire is mounted than at the outer portion during high-speed traveling, and heel-and-toe wear tends to occur.

  Accordingly, an object of the present invention is to provide a pneumatic tire that can achieve both suppression of pattern noise and improvement of heel-and-toe wear resistance.

  In order to solve the above problems, a pneumatic tire according to the present invention is a pneumatic tire in which a mounting direction of a tire front and back with respect to a vehicle is specified, and includes a plurality of circumferential grooves extending in the tire circumferential direction, and the plurality of circumferential tires A tread pattern in which a plurality of pitch types having different pitch lengths are distributed and arranged in the tire circumferential direction by a first pitch arrangement is formed on the vehicle inner side of the circumferential groove located on the innermost side of the vehicle among the directional grooves. A tread pattern in which a plurality of pitch types having different pitch lengths are distributed and arranged in the tire circumferential direction by a second pitch arrangement is formed on the vehicle outer side of the circumferential groove positioned on the outermost side of the circumferential grooves, When the pitch types are arranged in the order of the pitch length, when the adjacent pitch types are the adjacent pitch types, the first pitch array has the pitch types adjacent in the tire circumferential direction. The pitch arrangement is the same pitch type or the adjacent pitch type, and the second pitch arrangement includes a portion where a pitch type other than the adjacent pitch type is adjacent in the tire circumferential direction, and among the plurality of pitch types The pitch arrangement is characterized in that the number of consecutive pitch types having the shortest pitch length is 3 or less.

  Further, in the second pitch arrangement, the number of consecutive pitch types included in a range where the pitch length is 10% longer than the pitch length of the pitch type having the shortest pitch length among the plurality of pitch types is 3 It is preferable that there are no more.

  Further, the ratio of the pitch lengths of the adjacent pitch types is preferably 0.85 or more and 1.15 or less.

  Moreover, it is preferable that the number of pitch types used for the first pitch arrangement is the same as the number of pitch types used for the second pitch arrangement.

  A plurality of pitch types having different pitch lengths are arranged between the circumferential groove located on the innermost side of the vehicle and the circumferential groove located on the outermost side of the plurality of circumferential grooves by a third pitch arrangement. A tread pattern distributed in the circumferential direction is formed, and the third pitch arrangement is a pitch arrangement in which the pitch types adjacent in the tire circumferential direction are the same pitch type or the adjacent pitch type, and is used for the first pitch arrangement. The number of pitch types to be used is preferably larger than the number of pitch types used in the third pitch arrangement.

  Further, among the plurality of circumferential grooves, a plurality of pitch types having different pitch lengths are arranged between the circumferential groove located on the innermost side of the vehicle and the circumferential groove located on the outermost side of the vehicle by a fourth pitch arrangement. A tread pattern distributed in the circumferential direction is formed, and the fourth pitch arrangement includes a portion where a pitch type other than the adjacent pitch type is adjacent in the tire circumferential direction, and the pitch length is the longest among the plurality of pitch types. It is a pitch arrangement in which the number of consecutive short pitch types is three or less, and the number of pitch types used in the fourth pitch arrangement is preferably larger than the number of pitch types used in the second pitch arrangement.

  According to the pneumatic tire of the present invention, both suppression of pattern noise and improvement of heel-and-toe wear performance can be achieved.

It is an expanded view which shows an example of the tread pattern of the pneumatic tire of 1st Embodiment. (A) is a figure which shows an example of a 1st pitch arrangement | sequence, (b) is a figure which shows an example of a 2nd pitch arrangement | sequence. (A) is a figure which shows an example of a 3rd pitch arrangement | sequence, (b) is a figure which shows an example of a 4th pitch arrangement | sequence.

<First Embodiment>
Hereinafter, the pneumatic tire of the present invention is explained based on an embodiment.
The pneumatic tire according to the embodiment described below can be applied to, for example, a passenger car tire defined in Chapter A of JATMA YEAR BOOK 2009 (Japan Automobile Tire Association Standard). In addition, the pneumatic tire of the present invention can be applied to a small truck tire defined in Chapter B or a truck and bus tire defined in Chapter C.

  In the following description, the tire width direction is a direction parallel to the rotation axis of the pneumatic tire. Further, the outward in the tire width direction is a direction away from the tire center line CL in the tire width direction. The inner side in the tire width direction is a direction approaching the tire center line CL in the tire width direction. Further, the tire circumferential direction is a direction in which the rotation axis of the pneumatic tire rotates around the rotation center.

  First, the tread pattern of the pneumatic tire of this embodiment will be described with reference to FIG. FIG. 1 is a development view showing an example of a tread pattern 10 provided on the tread of the pneumatic tire of the present embodiment. In the pneumatic tire of this embodiment, the mounting direction of the tire front and back with respect to the vehicle is specified. In the example shown in FIG. 1, the right direction in FIG. 1 is the vehicle outer side, and the left direction is the vehicle inner side.

The tread pattern 10 includes circumferential ribs 12 and 14, a block 16, and a shoulder block 18 in order from the tire center line CL.
The tread pattern 10 is divided into a center region and a shoulder region by a circumferential groove 20 provided between the block 16 and the shoulder block 18. In the following description, a region outside in the tire width direction from the circumferential groove formed on the outermost side in the tire width direction is defined as a shoulder region. In particular, a shoulder region located outside the vehicle is defined as an outer shoulder region, and a shoulder region located inside the vehicle is defined as an inner shoulder region. Further, a region in the tire width direction inner side than the circumferential groove formed on the outermost side in the tire width direction is defined as a center region.

The circumferential rib 12 is defined by two circumferential grooves 22. The circumferential rib 12 is provided with an inclined lug groove 24 whose one end is closed.
The circumferential rib 14 is defined between the circumferential groove 22 and the circumferential narrow groove 26.

The block 16 is defined by a circumferential narrow groove 26, a circumferential groove 20, and an inclined lug groove 28 that connects the circumferential narrow groove 26 and the circumferential groove 20.
The shoulder block 18 is defined by a shoulder lug groove 30 that communicates between the circumferential groove 20 and the shoulder end. The shoulder block 18 is provided with a shoulder closing lug groove 32 that extends from the shoulder end and closes in the middle of the shoulder block 18.

The groove widths of the circumferential grooves 20 and 22 are, for example, 6 mm or more and 9 mm or less, and the groove depths of the circumferential grooves 20 and 22 are, for example, 7 mm or more and 9 mm or less. The groove width of the circumferential narrow groove 26 is, for example, 1 mm or more and 3 mm or less, and the groove depth of the circumferential narrow groove 26 is, for example, 4 mm or more and 5 mm or less.
The groove width of the inclined lug groove 24 is, for example, 2 mm to 6 mm, and the groove depth of the inclined lug groove 24 is, for example, 3 mm to 7 mm. The groove width of the inclined lug groove 28 is, for example, 2 mm or more and 7 mm or less, and the groove depth of the inclined lug groove 28 is, for example, 3 mm or more and 7 mm or less.
The shoulder lug groove 30 has a groove width of, for example, 2 mm or more and 4 mm or less, and the shoulder lug groove 30 has a groove depth of, for example, 3 mm or more and 6 mm or less. The groove width of the shoulder closing lug groove 32 is, for example, 2 mm or more and 4 mm or less, and the groove depth of the shoulder closing lug groove 32 is, for example, 3 mm or more and 6 mm or less.

  The circumferential grooves 20 and 22 and the circumferential narrow groove 26 are not limited to grooves parallel to the tire center line CL as shown in FIG. The circumferential grooves 20, 22 and the circumferential narrow groove 26 include, for example, grooves that are inclined at an angle of 35 degrees or less with respect to the tire center line CL.

Next, pitch variations applied to the tread pattern 10 of the present embodiment will be described. Here, the pitch of the tread pattern 10 is a minimum unit in which the same pattern is repeated along the tire circumferential direction. The pitches indicated by Pc ₁ and Pc ₂ in FIG. 1 indicate the pitches arranged in the center region. Further, the pitches indicated by Psh ₁ and Psh ₂ in FIG. 1 indicate the pitches arranged in the outer shoulder region.

  In the pneumatic tire of the present embodiment, a tread pattern in which a plurality of pitch types having different pitch lengths are distributed in the tire circumferential direction by the first pitch arrangement on the vehicle inner side than the tire center line CL, including the inner shoulder region. Is formed. Further, a tread pattern in which a plurality of pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the second pitch arrangement is formed outside the tire center line CL including the outer shoulder region. The definitions of the first pitch arrangement and the second pitch arrangement will be described later.

Hereinafter, the first pitch arrangement and the second pitch arrangement will be described with reference to FIG. FIG. 2A is a diagram illustrating an example of the first pitch arrangement, and FIG. 2B is a diagram illustrating an example of the second pitch arrangement. In the example shown in FIG. 2, a pitch arrangement using five pitch types A to E having different pitch lengths is shown. If the pitch lengths of the five pitch types A to E are P _{A to} P _E , respectively, P _A > P _B > P _C > P _D > P _E.

  For example, in the first pitch arrangement shown in FIG. 2 (a), the tire circumference is in the order of three pitch types A, three pitch types B, four pitch types C, four pitch types D, and so on. It shows that each pitch is arranged in the direction. Further, the second pitch arrangement shown in FIG. 2 (b) has two pitch types B, two pitch types C, three pitch types A, one pitch type B,. It shows that each pitch is arranged in the direction.

  Here, when a plurality of pitch types A to E are arranged in the order of pitch length, adjacent pitch types are defined as adjacent pitch types. For example, the pitch type B is adjacent to the pitch type A. The adjacent pitch types for pitch type B are pitch type A and pitch type C. The adjacent pitch types for pitch type C are pitch type B and pitch type D. The adjacent pitch types for the pitch type D are the pitch type C and the pitch type E. An adjacent pitch type with respect to the pitch type E is a pitch type D.

Note that the ratio of the pitch lengths of adjacent pitch types is preferably 0.85 or more and 1.15 or less. This means that the difference in pitch length between adjacent pitch types is within 15%.
For example, the pitch lengths of the pitch types A to E in the first pitch arrangement shown in FIG. 2A are P _A = 39.00 mm, P _B = 35.50 mm, P _C = 30.90 mm, and P _D = 26. 90 mm, P _E = 25.40 mm. Also, the pitch lengths of the pitch types A to E in the second pitch arrangement shown in FIG. 2B are P _A = 37.20 mm, P _B = 34.30 mm, P _C = 31.20 mm, P _D = 28. .10 mm, P _E = 25.00 mm.

Here, a pitch arrangement in which the pitch types adjacent in the tire circumferential direction (for example, Pc ₁ and Pc ₂ shown in FIG. 1) are the same pitch type or adjacent pitch types is defined as the first pitch arrangement. For example, like the portion indicated by “A3” in FIG. 2A, a portion where three pitch types A are continuous is a portion where the pitch types adjacent to each other in the tire circumferential direction are the same pitch type. Further, the third pitch type A of the three consecutive pitch types A and the next are arranged like “B3” next to “A3” shown in FIG. The first pitch type B of three consecutive pitch types B is a portion where the pitch type adjacent in the tire circumferential direction becomes the adjacent pitch type.

  In addition, the second pitch arrangement includes a portion in which a pitch type other than the adjacent pitch type is adjacent in the tire circumferential direction, and the number of consecutive pitch types having the shortest pitch length among the plurality of pitch types is 3 or less. It is defined as pitch arrangement. For example, in the second pitch arrangement, the pitch type A which is a pitch type other than the adjacent pitch type is adjacent to the pitch type C, as in the portion indicated by “A3” next to “C2” in FIG. With parts. Further, like the portions indicated by “E1” and “E2” in FIG. 2B, the second pitch arrangement is a number in which the pitch types E having the shortest pitch length among the plurality of pitch types A to E are consecutive. Is a pitch arrangement of 3 or less.

  In this embodiment, the example in which the first pitch array and the second pitch array are formed using the five pitch types A to E has been described. However, in order to form the first pitch array and the second pitch array. The number of pitch types used is not limited to this. For example, the pitch type used to form the first pitch array and the second pitch array under the condition that the pitch length of the pitch type with the longest pitch length and the pitch length of the pitch type with the shortest pitch length are constant. When the number is increased, the difference in pitch length between adjacent pitch types becomes smaller. In such a case, the second pitch arrangement is a number in which pitch types included in a range where the pitch length is 10% longer than the pitch length of the pitch type having the shortest pitch length among a plurality of pitch types are consecutively adjacent. Is preferably 3 or less.

In the pneumatic tire of the present embodiment, since the pitch arrangement of the first pitch arrangement described above is formed in the inner shoulder region, the difference in block rigidity that occurs between adjacent pitches in the tire circumferential direction in the inner shoulder region is reduced. be able to. Therefore, it is possible to suppress the occurrence of heel and toe wear in the inner shoulder region that is attached to the vehicle with a negative camber and has a heavy load.
In the pneumatic tire of the present embodiment, the pitch arrangement of the second pitch arrangement described above is formed in the outer shoulder region. Therefore, generation of pattern noise can be suppressed in the outer shoulder region that greatly contributes to generation of pattern noise.

  In the present embodiment, the number of pitch types used in the first pitch arrangement and the number of pitch types used in the second pitch arrangement are both five, but the number of pitch types used in the first pitch arrangement. May be different from the number of pitch types used in the second pitch arrangement.

<Second Embodiment>
Next, a pneumatic tire according to a second embodiment will be described. The basic configuration of the pneumatic tire of this embodiment is the same as that of the first embodiment. The pneumatic tire of this embodiment differs from the first embodiment in the pitch variation applied to the tread pattern 10. Hereinafter, pitch variations applied to the tread pattern 10 of the present embodiment will be described.

Similar to the first embodiment, in the inner shoulder region of the pneumatic tire of the present embodiment, a plurality of (for example, five) pitch types having different pitch lengths are distributed in the tire circumferential direction by the first pitch arrangement. A pattern is formed. Further, in the outer shoulder region of the pneumatic tire of the present embodiment, a tread pattern is formed in which a plurality of (for example, five) pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the second pitch arrangement. .
Furthermore, in the center region of the pneumatic tire of the present embodiment, a tread pattern is formed in which a plurality of (for example, three) pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the third pitch arrangement.

Hereinafter, the third pitch arrangement will be described with reference to FIG. FIG. 3A is a diagram illustrating an example of the third pitch arrangement. In the example shown in FIG. 3A, a pitch arrangement using three types of pitches A, B, and C having different pitch lengths is shown.
For example, in the third pitch arrangement shown in FIG. 3A, the tire circumference is in the order of two pitch types B, two pitch types C, one pitch type B, one pitch type A, and so on. It shows that each pitch is arranged in the direction.
Similar to the first pitch arrangement, the third pitch arrangement is also a pitch arrangement in which the pitch types adjacent in the tire circumferential direction are the same pitch type or adjacent pitch types.

In the pneumatic tire of the present embodiment, not only the first pitch array formed in the inner shoulder region, but also the third pitch array formed in the center region has the same pitch type in the tire circumferential direction. Or it is the pitch arrangement | sequence which is an adjacent pitch seed | species. Therefore, not only the inner shoulder region but also the center region, the difference in rigidity between adjacent pitches is reduced, and the occurrence of heel and toe wear can be suppressed compared to the first embodiment.
In particular, the number of pitch types used in the first pitch array formed in the inner shoulder region where heel-and-toe wear is likely to occur is greater than the number of pitch types used in the third pitch array formed in the center region. By increasing the number, the occurrence of heel and toe wear can be more effectively suppressed.

<Third Embodiment>
Next, a pneumatic tire according to a third embodiment will be described. The basic configuration of the pneumatic tire of this embodiment is the same as that of the first embodiment. The pneumatic tire of this embodiment differs from the first embodiment in the pitch variation applied to the tread pattern 10. Hereinafter, pitch variations applied to the tread pattern 10 of the present embodiment will be described.

In the inner shoulder region of the pneumatic tire of the present embodiment, a tread pattern is formed in which a plurality (for example, five) pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the first pitch arrangement. Further, in the outer shoulder region of the pneumatic tire of the present embodiment, a tread pattern is formed in which a plurality of (for example, five) pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the second pitch arrangement. .
Furthermore, in the center region of the pneumatic tire of the present embodiment, a tread pattern is formed in which a plurality of (for example, six) pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the fourth pitch arrangement.

Hereinafter, the fourth pitch arrangement will be described with reference to FIG. FIG. 3B is a diagram illustrating an example of the fourth pitch arrangement. In the example shown in FIG. 3B, a pitch arrangement using six pitch types A to F having different pitch lengths is shown. When 5 kinds of pitch length of the pitch species A~E a and _P A to P _{E, respectively,} are _{P A> P B> P C} > P D> P E> P F. Also, the pitch lengths of the pitch types A to F in the fourth pitch arrangement shown in FIG. 3B are P _A = 37.20 mm, P _B = 34.30 mm, P _C = 31.20 mm, P _D = 28. .10 mm, P _E = 25.00 mm, P _F = 22.1 mm.
For example, in the fourth pitch arrangement shown in FIG. 3 (b), two pitch types B, one pitch type E, one pitch type B, one pitch type F,... It shows that each pitch is arranged in the direction.
Similar to the second pitch arrangement, the fourth pitch arrangement is a pitch arrangement in which the number of consecutive pitch types F having the shortest pitch length among the plurality of pitch types A to F is three or less.

  In the pneumatic tire of the present embodiment, the number of pitch types used in the fourth pitch arrangement formed in the center region where heel and toe wear is more likely to occur than in the outer shoulder region is formed in the outer shoulder region. More than the number of pitch types used in the second pitch arrangement. Therefore, the difference in rigidity between adjacent pitches in the center region is reduced, and the occurrence of heel and toe wear can be suppressed.

  The test which confirms the effect of this invention was done using the various pneumatic tires. The tire size was 205 / 55R16, and the air pressure conditions defined in JATMA YEAR BOOK 2009 (Japan Automobile Tire Association Standard) were used. The load condition was a condition defined by JATMA YEAR BOOK 2009. The camber angle was -1.5 degrees. Each test tire was mounted on four wheels of a 1.5 L class front-wheel drive vehicle, a load of 80% of the normal load was applied, and the following test was performed.

(Pattern noise performance)
The driver sensorially evaluated the pattern noise when traveling at 100 km / h on a smooth road surface. The evaluation result of the comparative example 1 mentioned later is set to 100, and it shows that pattern noise is so small that an index value is high.

(Heel and toe wear resistance)
After traveling 10,000 km on a vehicle equipped with each test tire, the magnitude of heel and toe wear was examined. The measurement result of Comparative Example 1 to be described later is set to 100, and the higher the index value, the less likely the heel and toe wear occurs.

Example 1
First, the tread pattern 10 of the pneumatic tire of Example 1 will be described. The tread pattern 10 of the pneumatic tire of the first embodiment includes a first pitch arrangement in which the inner side of the vehicle including the inner shoulder region has five types of pitch types as shown in FIG. It is formed with. Further, the outer side of the vehicle including the outer shoulder region is formed in a second pitch arrangement having five kinds of pitch types as shown in FIG.

(Comparative Example 1)
Next, the tread pattern 10 of the pneumatic tire of Comparative Example 1 will be described. The tread pattern 10 of the pneumatic tire of Comparative Example 1 is formed in a first pitch arrangement in which the inner shoulder region, the outer shoulder region, and the center region have five kinds of pitch types as shown in FIG. .

(Comparative Example 2)
Next, the tread pattern 10 of the pneumatic tire of Comparative Example 2 will be described. The tread pattern 10 of the pneumatic tire of Comparative Example 2 is formed in a second pitch arrangement in which the inner shoulder region, the outer shoulder region, and the center region have five kinds of pitch types as shown in FIG. .

Table 1 shows the test results of pattern noise performance and heel and toe wear resistance (H & T wear resistance) in the pneumatic tires of Comparative Examples 1 and 2 and Example 1.

  From the results of Table 1, in the pneumatic tire of Example 1, the pitch arrangement of the first pitch arrangement is formed in the inner shoulder region, and the pitch arrangement of the second pitch arrangement is formed in the outer shoulder region. It can be seen that both suppression and improved heel and toe wear performance can be achieved.

(Examples 2 and 3)
Next, the pneumatic tires of Examples 2 and 3 will be described.
The tread pattern 10 of the pneumatic tire of Example 2 is formed in a first pitch arrangement in which the inner shoulder region has five kinds of pitch types as shown in FIG. Further, the outer shoulder region is formed in a second pitch arrangement having five kinds of pitch types as shown in FIG. Further, the tread pattern 10 of the pneumatic tire of Example 2 is formed in a third pitch arrangement in which the center region has three kinds of pitch types as shown in FIG.

  The tread pattern 10 of the pneumatic tire of Example 3 is formed in a first pitch arrangement in which the inner shoulder region has five types of pitch types as shown in FIG. Further, the outer shoulder region is formed in a second pitch arrangement as shown in FIG. 2B having five types of pitch. Further, the tread pattern 10 of the pneumatic tire of Example 3 is formed in a fourth pitch arrangement in which the center region has six kinds of pitch types as shown in FIG.

Table 2 shows the test results of pattern noise performance and heel and toe wear resistance of the pneumatic tires of Comparative Examples 1 and 2 and Examples 2 and 3.

From the results of Table 2, in the pneumatic tire of Example 2, the pitch arrangement of the first pitch arrangement is formed in the inner shoulder area, the pitch arrangement of the second pitch arrangement is formed in the outer shoulder area, and the third pitch arrangement It can be seen that since the pitch arrangement is formed in the center region, the heel and toe wear resistance is further improved.
In the pneumatic tire of Example 3, the pitch array of the first pitch array is formed in the inner shoulder region, the pitch array of the second pitch array is formed in the outer shoulder region, and the pitch array of the fourth pitch array is the center. Since it is formed in the region, it can be seen that the heel-and-toe wear resistance performance is further improved.

  As mentioned above, although the pneumatic tire of this invention was demonstrated in detail, this invention is not limited to the said embodiment. It goes without saying that various improvements and modifications may be made without departing from the spirit of the present invention.

10 tread pattern 12, 14 circumferential rib 16 block 18 shoulder block 20, 22 circumferential groove 24, 28 inclined lug groove 26 circumferential narrow groove 30 shoulder lug groove 32 shoulder closing lug groove

Claims (6)

A pneumatic tire in which the mounting direction of the tire front and back with respect to the vehicle is specified
A plurality of circumferential grooves extending in the tire circumferential direction,
A tread pattern in which a plurality of pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the first pitch arrangement is formed on the vehicle inner side of the circumferential groove located on the innermost side of the vehicle among the plurality of circumferential grooves. ,
A tread pattern in which a plurality of pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the second pitch arrangement is formed on the vehicle outer side of the circumferential groove positioned on the outermost side of the plurality of circumferential grooves. ,
When arranging the plurality of pitch types in the order of the pitch length, when the adjacent pitch types are the adjacent pitch types,
The first pitch arrangement is a pitch arrangement in which the pitch types adjacent in the tire circumferential direction are the same pitch type or the adjacent pitch type.
The second pitch arrangement includes a portion where a pitch type other than the adjacent pitch type is adjacent in the tire circumferential direction, and the number of consecutive pitch types having the shortest pitch length among the plurality of pitch types is 3 or less. A pneumatic tire having a pitch arrangement.   In the second pitch arrangement, the number of adjacent pitch types included in a range where the pitch length is 10% longer than the pitch length of the shortest pitch type among the plurality of pitch types is 3 or less. The pneumatic tire according to claim 1, wherein   The pneumatic tire according to claim 1 or 2, wherein a ratio of pitch lengths of the adjacent pitch types is 0.85 or more and 1.15 or less.   The pneumatic tire according to any one of claims 1 to 3, wherein the number of pitch types used for the first pitch arrangement and the number of pitch types used for the second pitch arrangement are the same. Among the plurality of circumferential grooves, a plurality of pitch types having different pitch lengths are arranged between the circumferential groove located on the innermost side of the vehicle and the circumferential groove located on the outermost side of the vehicle by the third pitch arrangement. A tread pattern distributed in the form is formed,
The third pitch arrangement is a pitch arrangement in which the pitch types adjacent in the tire circumferential direction are the same pitch type or the adjacent pitch type.
The pneumatic tire according to any one of claims 1 to 3, wherein the number of pitch types used in the first pitch arrangement is greater than the number of pitch types used in the third pitch arrangement. Among the plurality of circumferential grooves, a plurality of pitch types having different pitch lengths are arranged between the circumferential groove located on the innermost side of the vehicle and the circumferential groove located on the outermost side of the vehicle by a fourth pitch arrangement. A tread pattern distributed in the form is formed,
The fourth pitch arrangement includes a portion where a pitch type other than the adjacent pitch type is adjacent in the tire circumferential direction, and the number of consecutive pitch types having the shortest pitch length among the plurality of pitch types is 3 or less. A pitch arrangement,
The pneumatic tire according to any one of claims 1 to 3, wherein the number of pitch types used in the fourth pitch arrangement is greater than the number of pitch types used in the second pitch arrangement.