JP2011255805A - Pneumatic tire, determination method of tread pattern of the pneumatic tire, and method of manufacturing the tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve driving stability and to suppress heel and toe abrasion while maintaining the low pattern noise in a pneumatic tire.SOLUTION: A tread part of the pneumatic tire includes a shoulder side pattern region in which a plurality of pitch variations having different pitch length are dispersed in a tire circumferential direction by a first pitch array, and a center side pattern region in which a plurality of pitch variations having different pitch length are dispersed in the tire circumferential direction by a second pitch array while having a circumferential groove as a boundary. When the plurality of pitch variations are arranged in order of the pitch length and the pitch variations adjacent with each other are defined as adjacent pitch variations, the first pitch array has the same pitch variation or the adjacent pitch variation in the pitch adjacent in the tire circumferential direction, and the second pitch array has a part having a pitch variation other than the adjacent pitch variation in the pitch adjacent in the tire circumferential direction, and the pitch variations of the shortest pitch length are continuously adjacent in the number of three or less.

Description

  The present invention relates to a pneumatic tire provided with a tread pattern, and a tread pattern determination method for a pneumatic tire. And a method for manufacturing a tire.

Conventionally, a pneumatic tire having a tread pattern has been provided with a pitch variation in which the pattern pitch length is dispersed in the tire circumferential direction in order to reduce pattern noise.
Pitch variation refers to distributing the pattern noise frequency by dispersing 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.
Since the pitch variation has a very large degree of freedom in how to distribute the pitch length, more and more pitch variations and pneumatic tires to which the 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. It comprises a pattern constituent unit row arranged to include the pattern constituent units arranged at intervals of one or more adjacent pitches, and has a test subject pattern constituent unit row 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 is arranged 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. Therefore, it is possible to suppress a decrease in responsiveness due to a decrease in block rigidity in steering stability.
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. May cause wear. The heel & toe wear refers to a form in which the wear difference between adjacent land portions in the tire circumferential direction is greatly different and a wear step is generated in a sawtooth shape in the tire circumferential direction. When rolling tires, there are many cases where noise occurs when the heel and toe wear parts touch the ground.

  In the pneumatic tire described in Patent Document 2, it is possible to achieve both improvement in steering stability on a dry road surface and reduction in pattern noise. However, there is nothing about suppression of heel and toe wear. Not mentioned.

  Accordingly, the present invention provides a pneumatic tire capable of improving steering stability and suppressing heel & toe wear while maintaining low pattern noise, a method for determining a tread pattern of the pneumatic tire, It aims at providing the manufacturing method of a tire.

One embodiment of the present invention is a pneumatic tire provided with a tread pattern.
The pneumatic tire
The pneumatic tire has a circumferential groove in a tread portion,
The tread portion includes a shoulder-side pattern region in which a plurality of pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the first pitch arrangement, and a plurality of pitch types having different pitch lengths in the tire circumferential direction by the second pitch arrangement. And the center-side pattern region dispersedly arranged at the circumferential groove.
When arranging the plurality of pitch types in the order of the pitch length, when adjacent pitch types are referred to as adjacent pitch types,
The first pitch arrangement is an arrangement in which the same pitch type or the adjacent pitch type is arranged in a pitch adjacent to the tire circumferential direction,
The second pitch arrangement includes a portion in which a pitch type other than the adjacent pitch type is arranged on a pitch adjacent to the tire circumferential direction, and the number of adjacent pitch types having the shortest pitch length is 3 or less. Is an array.

  In addition, it is preferable that the second pitch arrangement is an arrangement in which the number of adjacent pitch types included in a range where the pitch length is 10% longer than the shortest pitch length is 3 or less. .

  The ratio of the pitch lengths of the adjacent pitch species is preferably 0.85 to 1.15.

  Further, the number of the plurality of pitch types used for the first pitch arrangement and the number of the plurality of pitch types used for the second pitch arrangement may be the same.

Furthermore, the circumferential groove and the shoulder pattern region are provided in each of the half tread portions on both sides with the center line of the tread portion as a boundary,
When the pneumatic tire is mounted on a regular rim and the width in the tire direction of the ground shape measured under the conditions of regular internal pressure and 80% of the regular load is determined as the ground width at the tread portion, The directional groove is preferably located within a range of 30 to 80% of the ground contact width of the tread portion with the center line as the center.

  It is preferable that the plurality of pitch types used for the first pitch arrangement in each of the half tread portions is the same.

Furthermore, another aspect of the present invention is a method for determining a tread pattern of a pneumatic tire,
A plurality of pitch types having different pitch lengths and the number of arrangement of the pitch types are determined corresponding to the shoulder circumference at a predetermined position located on the shoulder side from the center line of the tread portion, and the first pitch arrangement in the shoulder side region The step of arranging the pitch with,
A plurality of pitch types having different pitch lengths and a number of arrangement of each of the pitch types corresponding to the center circumference in the center line, and arranging the pitches in the second pitch arrangement in the pattern area on the center side;
Integrating the pitch arranged in the pattern area on the center side and the pitch arranged in the pattern area on the shoulder side, and performing an order analysis;
According to the result of the order analysis, by shifting the position in the tire circumferential direction between the second pitch array of the center side pattern area and the first pitch array of the shoulder side pattern area, Determining a tread pattern.
When arranging the plurality of pitch types in the order of the pitch length, when adjacent pitch types are referred to as adjacent pitch types,
The first pitch arrangement is an arrangement in which the same pitch type or the adjacent pitch type is arranged between adjacent pitches in the tire circumferential direction.
The second pitch arrangement includes a portion in which pitch types other than the adjacent pitch type are arranged between adjacent pitches in the tire circumferential direction, and the number of adjacent pitch types having the shortest pitch length is 3 or less. An array.

  Still another aspect of the present invention provides a tire manufacturing method for manufacturing a tire with a tread pattern by manufacturing a vulcanization mold based on the tread pattern created using the tread pattern determination method of the pneumatic tire. It is.

  According to the pneumatic tire and the determination method of the tread pattern of the pneumatic tire, it is possible to improve steering stability and suppress heel and toe wear while maintaining low pattern noise.

It is an expanded view of the tread pattern of the pneumatic tire for passenger cars of this embodiment. (A), (b) is a figure explaining the pitch variation in the tread pattern shown in FIG. It is a graph of the order analysis result by the conventional pitch variation. It is a graph of the order analysis result by the pitch variation of this embodiment.

  Hereinafter, the pneumatic tire, the tread pattern determination method of the pneumatic tire, and the tire manufacturing method of the present invention will be described in detail.

(Tread pattern)
FIG. 1 is a development view of a tread pattern 10 provided on a tread of a passenger car pneumatic tire (hereinafter referred to as a tire) according to the present embodiment. The tread pattern 10 is a point-symmetric pattern around the tire center line CL.
The passenger car tire according to the present embodiment refers to a tire defined in Chapter A of JATMA YEAR BOOK 2008 (Japan Automobile Tire Association Standard), for example. 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.

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 pattern region on the center side and a pattern region on the shoulder side by a circumferential groove 20 provided between the block 16 and the shoulder block 18.
The circumferential rib 12 is defined by two circumferential grooves 22, and 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 provided with a shoulder lug groove 30 that communicates between the circumferential groove 20 and the shoulder end, and a shoulder closing lug groove 32 that extends from the shoulder end and closes halfway.

For the circumferential grooves 20 and 22, for example, the groove width is 6 to 9 mm, and the groove depth is 7 to 9 mm. For the circumferential narrow groove 26, for example, the groove width is 1 to 3 mm, and the groove depth is 4 to 5 mm. For the inclined lug groove 24, for example, the groove width is 2 to 6 mm, and the groove depth is 3 to 7 mm.
Moreover, about the inclination lug groove | channel 28, for example, a groove width is 2-7 mm and a groove depth is 3-7 mm.
For the shoulder lug groove 30 in the pattern region on the shoulder side, for example, the groove width is 2 to 4 mm and the groove depth is 3 to 6 mm. For the shoulder closing lug groove 32, for example, the groove width is 2 to 4 mm, and the groove depth is 3 to 6 mm.

The circumferential grooves 20 on both sides of the tread pattern 10 are preferably located within a range of 30 to 98% of the ground contact width of the tread portion around the center line, and more preferably within a range of 50 to 70%. . The contact width of the tread portion refers to the width in the tire direction of the contact shape measured when the tire is mounted on a normal rim and is measured under the conditions of normal internal pressure and 80% of the normal load.
Here, the regular rim means “standard rim” defined in JATMA, “Design Rim” defined in TRA, or “Measuring Rim” defined in ETRTO. The normal internal pressure means “maximum air pressure” defined by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. The normal load means the “maximum load capacity” defined in JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined in TRA, or “LOAD CAPACITY” defined in ETRTO.

  As described above, the circumferential groove 20 is provided in the range of 30 to 98% of the ground contact width of the tread portion in one of the front wheels or the rear wheels of the mounted vehicle, for example, the tread portion of the rear wheel of the front wheel drive vehicle. In the pattern area between the circumferential grooves 20 on both sides (the pattern area on the center side), the tread block rigidity in the area that contacts the ground when the rear wheel is loaded is prevented from being reduced in a part on the tire circumference, and steering is performed. This is for suppressing the decrease in the responsiveness to the heel and toe wear in the pattern area outside the circumferential groove 20 on both sides (the pattern area on the shoulder side).

Such a tread pattern 10 has the following pitch variations.
Here, the pitch of the tread pattern 10 is a minimum unit in which the same pattern is repeated. For example, FIG. 1 shows the pitch length P ₁ of the pattern region on the shoulder side and the pitch length P ₂ of the pattern region on the center side.

  Specifically, with the circumferential groove 20 in the tread portion as a boundary, the pattern form on the shoulder side and the pattern area on the center side have different arrangement forms in which a plurality of pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction. . Here, when a plurality of pitch types are arranged in the order of the pitch length, when adjacent pitch types are referred to as adjacent pitch types, the pitch arrangement in the shoulder side region is the pitch adjacent to the tire circumferential direction in any pitch. An arrangement in which the same pitch seeds or adjacent pitch seeds are arranged. The pitch arrangement of the center side region includes a portion in which a pitch type other than the adjacent pitch type is arranged in the pitch adjacent to the tire circumferential direction, and the number of adjacent pitch types having the shortest pitch length is 3 or less. Is an array.

FIG. 2A is a diagram for explaining an example of the pitch arrangement in the center side region. Here, A to E are pitch types having different pitch lengths, and “A3” and “C2” in FIG. 2A mean that three pitch types A are continuous, and the pitch type C is It means that two are arranged in succession. Therefore, in the case of FIG. 2A, in order from the left, there are two pitch types B, two pitch types C, three pitch types A, one pitch type B, and one pitch type C. It means that the tires are arranged in order in the tire circumferential direction.
The pitch arrangement shown in FIG. 2A includes a portion in which a pitch type other than the adjacent pitch type is arranged on a pitch adjacent in the tire circumferential direction, and the number of adjacent pitch types having the shortest pitch length is 3 An array that is: For example, a pitch type A that is not an adjacent pitch type is arranged for the second “C2” from the left in FIG. Further, the shortest pitch type E is 1 or 2 or less continuously provided.
In the present embodiment, the number of adjacent pitch types having the shortest pitch length is two or less, but the number may be three or less.
Further, in the pitch arrangement shown in FIG. 2 (a), the number of adjacent pitch types included in a range where the pitch length is 10% longer than the shortest pitch length is 3 or less. It is preferable at the point which improves.

On the other hand, FIG. 2B is a diagram for explaining an example of the pitch arrangement of the pattern region on the shoulder side. Here, A to E are pitch types having different pitch lengths, and may be the same as or different from the pitch types A to E in FIG. In the example shown in FIGS. 2A and 2B, the pitch types A to E are different from each other. Note that “A3” and “B3” in the drawing mean that three pitch types A are continuous, and three pitch types B are continuous, as in the above description.
The pitch arrangement shown in FIG. 2 (b) is an arrangement in which the same pitch type or adjacent pitch type is arranged in the pitches adjacent in the tire circumferential direction. That is, when the pitch type changes, the adjacent pitch type is always arranged. For example, when the pitch type B changes, the pitch type A or the pitch type C is always arranged at the adjacent pitch.
Here, the ratio of the pitch lengths of the adjacent pitch types of the pitch types A to E is 0.85 to 1.15. By determining the pitch length ratio in this way, it is possible to improve steering stability and efficiently suppress heel and toe wear while maintaining low pattern noise.

FIG. 3 shows the order analysis result when pitch variation is performed on the center side region and the shoulder side region by the pitch arrangement shown in FIG. Moreover, the order analysis result when the pitch variation is performed in the center side region and the shoulder side region by the pitch arrangement shown in FIG.
In any case, since the number of pitches is 66, it can be seen that the order components are dispersed around the 66th order component. In particular, the pitch arrangement shown in FIG. 2A does not form a large peak and the order levels are dispersed.
FIG. 4 shows the order analysis result when the pitch arrangement shown in FIG. 2A is arranged in the center-side pattern area and the pitch arrangement shown in FIG. 2B is arranged in the shoulder-side area, that is, the pitch of this embodiment. The order analysis result in the sequence is shown. It can be seen that the 66th-order component is also dispersed in this pitch arrangement.

In this way, by adopting the pitch arrangement shown in FIG. 2A in the center side area and the pitch arrangement shown in FIG. 2B in the shoulder side area, pattern noise can be efficiently generated as in the conventional case. Can be reduced.
As shown in FIG. 2A, the pattern area on the center side of the tread pattern 10 includes a portion in which a pitch type other than the adjacent pitch type is arranged on the pitch adjacent in the tire circumferential direction. For this reason, the order component resulting from the pitch number can be efficiently dispersed. In addition, even if the pitch adjacent to the tire circumferential direction is provided with a pitch type other than the adjacent pitch type, the center side region is a region where heel and toe wear is unlikely to occur. There is no problem with the seeds. Moreover, in this pitch arrangement, since the number of adjacent pitch types having the shortest pitch length is 3 or less, only the shortest pitch type does not occupy the ground plane due to the continuous shortest pitch type. For this reason, in the tire, a portion where the block rigidity is reduced due to the shortest pitch length in the contact surface does not occur on the tire circumference. For this reason, in steering stability, there is no deterioration in steering response due to a decrease in block rigidity.

  On the other hand, the pattern region on the shoulder side in the tread pattern 10 is a region that is greatly affected by the heel and toe wear compared to the steering stability. However, as shown in FIG. 2B, an arrangement in which the same pitch type or adjacent pitch type is arranged in the pitches adjacent in the tire circumferential direction is used. For this reason, in the pattern area on the shoulder side, the difference in the rigidity of the block between the adjacent pitches is small. For this reason, heel & toe wear hardly occurs.

  In this way, the tread pattern 10 has a steering stability while maintaining low pattern noise by changing the pitch arrangement in consideration of the influence of the pattern area on the center side and the pattern area on the shoulder side on the tire performance. The heel & toe wear can be suppressed while suppressing the lowering.

In this embodiment, the number of pitch types in the center-side pattern region and the shoulder-side pattern region is five from A to E and the number of pitch types is the same, but it is not necessarily the same.
Further, although the pitch types in the pattern regions on the shoulder side are the same, they may be different. Further, the pitch arrangement may be the same or different.

(How to determine the tread pattern)
Next, a method for determining the pitch arrangement in the tread pattern 10 will be described. Specifically, the determination method is performed by a computer.

In the tread pattern determination method, first, the pitch length differs according to a predetermined position located on the shoulder side from the center line CL of the tread portion, in the example shown in FIG. A plurality of pitch types and the number of arrangements of the pitch types are determined, and the pitch is arranged in the pattern area on the shoulder side in a pitch arrangement as shown in FIG.
Similarly, a plurality of pitch types having different pitch lengths and the number of arrangements of the pitch types are determined corresponding to the center circumferential length in the center line CL, and the pattern area on the center side is as shown in FIG. Arrange the pitch by pitch arrangement. The pitch arrangement as shown in FIGS. 2A and 2B is determined in advance by using order analysis. FIGS. 2A and 2B are adapted to the shoulder circumference and the center circumference by calculating the lengths of the pitch types A to E according to the dimensions of the shoulder circumference and the center circumference. Such a pitch arrangement can be obtained by the computer.

Next, the computer analyzes the order by integrating the pitch arranged in the pattern area on the center side and the pitch arranged in the pattern area on the shoulder side. Specifically, the order analysis is performed on the waveform of one tire round in which the amplitude of vibration is changed according to the pitch length, or the waveform of one tire round obtained by changing the cycle in accordance with the pitch length. The
Next, the order analysis is performed by the computer shifting the position in the tire circumferential direction between the pitch arrangement of the center side pattern area and the first pitch arrangement of the shoulder side pattern area according to the result of the order analysis. As a result, the computer determines the tread pattern so that the peak value is the lowest.

The pitch arrangement shown in FIG. 2A suppresses a decrease in steering stability in the pattern area on the center side, and the pitch arrangement shown in FIG. 2B suppresses heel and toe wear in the pattern area on the shoulder side. Because it is an arrangement, phase stability is shifted between the pitch arrangement in the center pattern area and the first pitch arrangement in the shoulder pattern area to maintain steering stability and suppress heel and toe wear. However, it is possible to determine a pattern in which pattern noise is optimally reduced.
A vulcanization mold is produced based on the tread pattern created and determined by the computer in this manner, and a tire with a tread pattern is produced.

(Example)
The tire of this embodiment and the conventional tire were produced and evaluated for steering stability and heel & toe wear. The tire size of the tire to be evaluated is 205 / 60R16.
The tire was assembled on a regular rim, filled with regular internal pressure, mounted on four wheels of a 1.5-liter class front wheel drive vehicle, and evaluated by applying a load of 80% of the regular load. The normal rim, normal internal pressure, and normal load mentioned here are defined in the above-mentioned JATMA, ETRTO, and TRA.

Evaluation of steering stability is a sensory evaluation of the driver when driving on a dry road surface at 100 km / hour. On the other hand, heel & toe wear was evaluated by measuring the wear state of the tread pattern after running the front wheel drive vehicle for 10,000 km using calipers. Specifically, the level difference between the adjacent pitches of the tread pattern was measured to determine the level difference.
The sensory evaluation results and the level difference results were indexed based on Conventional Example 1. The larger the value of the index, the better the evaluation.

The evaluated tire is the tire of the example using the tread pattern shown in FIG. 1 and FIGS. 2 (a) and 2 (b), and the tread pattern shown in FIG. 1, with the pitch arrangement shown in FIG. 2 (b). Conventional tire 1 used for the entire pattern area on the center and shoulder sides, and the tread pattern shown in FIG. 1, and the conventional arrangement using the pitch arrangement shown in FIG. 2 (a) for the entire pattern area on the center and shoulder sides This is the tire of Example 2.
The center circumference of the tire centerline CL in the example is 2045 mm, the shoulder circumference in the circumferential groove 20 is 2020 mm, and according to this, the pitch types A to E in FIG. A = 37.2 mm, B = 34.3 mm, C = 31.2 mm, D = 28.1 mm, and E = 25.0 mm. In addition, regarding pitch types A to E in FIG. 2B, A = 39.0 mm, B = 35.5 mm, C = 30.9 mm, D = 26.9 mm, and E = 25.4 mm.
On the other hand, the pitch length of each pitch type on the shoulder side in Conventional Example 1 uses the pitch length shown in FIG. 2B, and the pitch length of each pitch type in the center side region is the center circumference with respect to the shoulder circumference. The ratio of the length was corrected and used by multiplying each pitch length of pitch types A to E shown in FIG.
In addition, the pitch length shown in FIG. 2A is used as the pitch length of each pitch type in the center side region in Conventional Example 2, and the pitch length of each pitch type on the shoulder side is the shoulder circumference relative to the center circumference. The length ratio was corrected by multiplying each pitch length of pitch types A to E shown in FIG.
The evaluation results are shown in the following table.

  From the above table, it can be seen that the embodiment makes it possible to achieve both steering stability and heel & toe wear, as compared with the conventional examples 1 and 2. Therefore, this embodiment can suppress heel and toe wear in the same manner as the pitch arrangement shown in FIG. 2B while improving steering stability while maintaining low pattern noise.

  As mentioned above, although the pneumatic tire, the determination method of the tread pattern of the pneumatic tire, and the manufacturing method of the tire of the present invention were explained in detail, the present invention is not limited to the above-mentioned embodiment, and in the range which does not deviate from the main point of the present invention. Of course, various improvements and changes may be made.

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 (8)

A pneumatic tire provided with a tread pattern,
The pneumatic tire has a circumferential groove in a tread portion,
The tread portion includes a shoulder-side pattern region in which a plurality of pitch types having different pitch lengths are dispersedly arranged in the tire circumferential direction by the first pitch arrangement, and a plurality of pitch types having different pitch lengths in the tire circumferential direction by the second pitch arrangement. And the pattern area on the center side distributed and arranged with the circumferential groove as a boundary,
When arranging the plurality of pitch types in the order of the pitch length, when adjacent pitch types are referred to as adjacent pitch types,
The first pitch arrangement is an arrangement in which the same pitch type or the adjacent pitch type is arranged in a pitch adjacent to the tire circumferential direction,
The second pitch arrangement includes a portion in which a pitch type other than the adjacent pitch type is arranged on a pitch adjacent to the tire circumferential direction, and the number of adjacent pitch types having the shortest pitch length is 3 or less. A pneumatic tire characterized by being an array.   2. The second pitch array is an array in which the number of adjacent pitch types included in a range where the pitch length is 10% longer than the shortest pitch length is 3 or less. Pneumatic tires.   The pneumatic tire according to claim 1 or 2, wherein a ratio of pitch lengths of the adjacent pitch types is 0.85 to 1.15.   The pneumatic tire according to any one of claims 1 to 3, wherein the number of the plurality of pitch types used for the first pitch arrangement and the number of the plurality of pitch types used for the second pitch arrangement are the same. The circumferential groove and the shoulder pattern region are provided in each of the half tread portions on both sides of the center line of the tread portion,
When the pneumatic tire is mounted on a regular rim and the width in the tire direction of the ground shape measured under the conditions of regular internal pressure and 80% of the regular load is determined as the ground width at the tread portion, 5. The pneumatic tire according to claim 1, wherein the directional groove is located within a range of 30 to 98% of a ground contact width of the tread portion with a center line as a center.   The pneumatic tire according to claim 5, wherein a plurality of pitch types used for the first pitch arrangement in each of the half tread portions is the same. A method for determining a tread pattern of a pneumatic tire,
Corresponding to the shoulder circumference at a predetermined position located on the shoulder side from the center line of the tread portion, a plurality of pitch types having different pitch lengths and the number of arrangement of each of the pitch types are determined, and the first pitch is set in the pattern region on the shoulder side. Arranging pitches in an array;
A plurality of pitch types having different pitch lengths and a number of arrangement of each of the pitch types corresponding to the center circumference in the center line, and arranging the pitches in the second pitch arrangement in the pattern area on the center side;
Integrating the pitch arranged in the pattern area on the center side and the pitch arranged in the pattern area on the shoulder side, and performing an order analysis;
According to the result of the order analysis, by shifting the position in the tire circumferential direction between the second pitch array of the center side pattern area and the first pitch array of the shoulder side pattern area, Determining a tread pattern;
When arranging the plurality of pitch types in the order of the pitch length, when adjacent pitch types are referred to as adjacent pitch types,
The first pitch arrangement is an arrangement in which the same pitch type or the adjacent pitch type is arranged between adjacent pitches in the tire circumferential direction.
The second pitch arrangement includes a portion in which pitch types other than the adjacent pitch type are arranged between adjacent pitches in the tire circumferential direction, and the number of adjacent pitch types having the shortest pitch length is 3 or less. A method for determining a tread pattern of a pneumatic tire, wherein the tread pattern is a certain arrangement.   A tire manufacturing method for manufacturing a tire with a tread pattern by manufacturing a mold for vulcanization based on a tread pattern created using the tread pattern determination method for a pneumatic tire according to claim 7.