JP2007045324A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of effectively reducing the noise attributable to the columnar resonance of a circumferential major groove. <P>SOLUTION: A plurality of land parts 51 are formed by combining a plurality of kinds of pitches on a tire tread of a tread part 12. A lug groove 32 is formed on each land part 51 along the direction across a circumferential main groove 22, each lug groove 32 is connected to the circumferential major groove 22 at one end of the groove longitudinal direction, and the other end in the groove longitudinal direction is terminated in each land part 51. In addition, the groove volume of the lug groove 32 is at least two kinds for the circumferential major groove in a tire ground contact surface. Thus, the pitch variation is introduced in the tread pattern, the lug groove 32 with one side closed in a bag shape is connected to the circumferential major groove 22, and the groove volume of the lug groove 32 is at least two kinds for the circumferential major groove 22 in the tire ground contact surface to enhance the reducing effect of the columnar resonance sound generated in the circumferential major groove 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire in which pitch variations are introduced into a tread pattern.

  Conventionally, with respect to the noise regulations of pneumatic tires that are becoming stricter year by year, noise reduction has been achieved by reducing the groove volume of the tire tread pattern as the main sound source.

  However, if the groove volume of the tread pattern is reduced, the noise of the pneumatic tire can be reduced. On the other hand, the drainage function of the groove formed in the tread pattern is lowered, so that the wet performance as a whole tire is lowered. Problem arises.

  Therefore, as a technology to reduce the noise of pneumatic tires while ensuring the wet performance of the entire tire, the tire circumferential length that combines each land portion with one of the lateral grooves that divide each land portion in the tire circumferential direction. There has been proposed a pneumatic tire in which pitch variations are introduced into a tread pattern by combining a plurality of pitches defined in the tire circumferential direction (see, for example, Patent Document 1).

According to the example described in Patent Document 1, it is said that by introducing pitch variations into the tread pattern, pattern noise generated along with the rolling of the pneumatic tire can be reduced.
JP-A-4-244402

  However, in the example described in Patent Document 1, when pitch variation is introduced into the tread pattern, it is assumed that the noise generated by the collision between each land portion and the road surface becomes uneven, and in order to prevent this, Rather, attention is paid to equalizing the surface pressure at the section, and no noise is caused by air column resonance in the circumferential main groove, which is said to occupy a large weight in the noise of pneumatic tires. There is a problem that it is not considered.

  The present invention has been made in view of the above circumstances, and the object thereof is to effectively reduce noise caused by air column resonance in the circumferential main groove, which is said to occupy a large weight in the noise of pneumatic tires. It is to provide a pneumatic tire that can be used.

  In order to solve the above-described problem, in the pneumatic tire according to claim 1, at least one circumferential main groove is formed along the tire circumferential direction on the tire tread surface of the tread portion and the circumferential main groove. By forming a plurality of lateral grooves intersecting with each other, a plurality of land portions are arranged along the tire circumferential direction, and one of the lateral grooves partitioning each land portion in the tire circumferential direction and each land portion are arranged. In the pneumatic tire having a plurality of types of pitches when the combined tire circumferential length is defined as a pitch, each land portion has at least one along the direction intersecting the circumferential main groove. The lug groove is formed such that one end portion in the groove longitudinal direction is connected to the circumferential main groove and opens, and the other end portion in the groove longitudinal direction terminates in each land portion. The groove volume of the lug groove is the circumferential main groove. There are is characterized in that has at least two or more kinds.

  Next, the operation of the pneumatic tire according to claim 1 will be described.

  In the pneumatic tire according to claim 1, at least one lug groove is formed in each land portion along a direction intersecting with the circumferential main groove, and one end of the lug groove in the longitudinal direction of the groove is circumferential. While being connected to the direction main groove and opening, the other end portion in the groove longitudinal direction is configured to terminate in each land portion. In this way, when the lug groove whose one side is closed like a bag is connected to the circumferential main groove, the sound pressure of the air column resonance generated in the circumferential main groove can be reduced by the side branch effect. That is, when a lug groove closed on one side in a bag shape is connected to the circumferential main groove, the frequency represented by the following formula (1) when the length in the longitudinal direction of the lug groove is L and the sound velocity is V: The air column resonance sound of f can be absorbed.

  f = (2n−1) · V / 4L (1)

  Where n: vibration order (n = 1, 3, 5...)

  In the present invention, since the groove volume (at least one of the groove length, groove depth, and groove width) of the lug groove is at least two kinds with respect to the circumferential main groove, it occurs in the circumferential main groove. The sound pressure reducing effect of the air column resonance can be varied (dispersed) depending on the groove volume of the lug groove.

  Furthermore, in the present invention, when the length in the tire circumferential direction in which each land portion is combined with one of the lateral grooves partitioning each land portion in the tire circumferential direction is defined as a pitch, a plurality of types of pitches are provided. Since pitch variation is introduced into the pattern, air column resonance generated in the circumferential main groove can be reduced.

  Thus, according to the present invention, the pitch variation is introduced into the tread pattern, the lug groove whose one side is closed like a bag is connected to the circumferential main groove, and the groove volume of the lug groove is set to the circumferential main groove. By using at least two types or more, it is possible to effectively reduce noise caused by air column resonance in the circumferential main groove, which is said to occupy a large weight in the noise of the pneumatic tire.

  Here, in the pneumatic tire according to claim 2, in the pneumatic tire according to claim 1, the length of the lug groove in the groove longitudinal direction is at least two kinds with respect to the circumferential main groove. It is characterized by being.

  Next, the operation of the pneumatic tire according to claim 2 will be described.

  In the pneumatic tire according to claim 2, since the length of the lug groove in the longitudinal direction of the lug groove is at least two kinds with respect to the circumferential main groove, the lug groove absorbs according to the above equation (1). The frequency f of the air column resonance that can be made can be varied (dispersed) depending on the length of the lug groove in the groove longitudinal direction.

  Thus, according to the pneumatic tire of the second aspect, since the effect of reducing the air column resonance generated in the circumferential main groove can be enhanced as compared with the conventional one, a large weight is added to the noise of the pneumatic tire. It is possible to more effectively reduce noise caused by air column resonance in the circumferential main groove which is supposed to be occupied.

  Further, in the pneumatic tire according to claim 3, in the pneumatic tire according to claim 1 or 2, the groove depth of the lug groove is at least two or more kinds with respect to the circumferential main groove. It is characterized by being.

  Next, the operation of the pneumatic tire according to claim 3 will be described.

  In the pneumatic tire according to claim 3, since the groove depth of the lug groove is at least two kinds with respect to the circumferential main groove, the effect of reducing the sound pressure of air column resonance generated in the circumferential main groove is reduced to the lag. It can be varied (dispersed) depending on the groove depth. Thereby, the reduction effect of the air column resonance generated in the circumferential main groove can be surely enhanced as compared with the conventional case.

  The pneumatic tire according to claim 4 is the pneumatic tire according to any one of claims 1 to 3, wherein the lug groove has at least two groove widths with respect to the circumferential main groove. This is a feature.

  Next, the operation of the pneumatic tire according to claim 4 will be described.

  In the pneumatic tire according to claim 4, since the groove width of the lug groove is at least two kinds with respect to the circumferential main groove, the effect of reducing the sound pressure of air column resonance generated in the circumferential main groove is reduced by the lug groove. It can be varied (dispersed) depending on the groove width. Thereby, the reduction effect of the air column resonance generated in the circumferential main groove can be surely enhanced as compared with the conventional case.

  Further, in the pneumatic tire according to claim 5, in the pneumatic tire according to any one of claims 1 to 4, the groove volume of the lug groove increases as the pitch increases. It is comprised by these.

  Next, the operation of the pneumatic tire according to claim 5 will be described.

  When the pitch, which is the length in the tire circumferential direction that combines each land portion with one of the lateral grooves that divide each land portion in the tire circumferential direction, increases the length in the tire circumferential direction of each land portion. The increase in the block rigidity tends to promote the generation of air column resonance in the circumferential main groove. However, as in the pneumatic tire according to claim 5, when the groove volume of the lug groove increases as the pitch increases, the block rigidity of each land portion is made uniform as a whole tire. Thus, the sound pressure of the air column resonance generated in the circumferential main groove can be effectively reduced.

  As described above, according to the pneumatic tire of the present invention, the effect of reducing the air column resonance generated in the circumferential main groove can be enhanced as compared with the conventional tire, so that a large weight is occupied in the noise of the pneumatic tire. The noise resulting from the air column resonance of the circumferential main groove, which is assumed to be, can be reduced more effectively.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the members, configurations, arrangements, and the like described below do not limit the present invention, and it is needless to say that various modifications can be made in accordance with the spirit of the present invention.

(Composition of pneumatic tire)
First, the configuration of a pneumatic tire according to an embodiment of the present invention will be described.

  1 is a developed view of a tread portion 12 of a pneumatic tire 10 according to an embodiment of the present invention, FIG. 2 is a sectional view of a circumferential main groove 22 and a lug groove 32 of FIG. 1, and FIG. 3 is a cross-sectional view of a directional main groove 20 and a lug groove 30. FIG.

  The pneumatic tire 10 according to an embodiment of the present invention is suitably used as a tire for a passenger car such as a large sedan, for example. First, the tread pattern of the pneumatic tire 10 of the present example will be briefly described. A pair of circumferential main grooves 20 along the tire circumferential direction is provided at the center of the tire tread surface of the tread portion 12 configured in the pneumatic tire 10. A pair of circumferential main grooves 22 are formed along the tire circumferential direction on both sides of the pair of circumferential main grooves 20.

  A circumferential narrow groove 24 is formed along the tire circumferential direction on the tire equator line CL between the pair of circumferential main grooves 20, and between the circumferential main groove 20 and the circumferential main groove 22. A pair of circumferential narrow grooves 26 are formed between the tire circumferential directions. Further, a pair of circumferential grooves 28 are formed along the tire circumferential direction near the tread end 14 outside the circumferential main groove 22 in the tire width direction.

  In the pneumatic tire 10 of this example, as described above, the circumferential main groove 20 and the circumferential main groove 22 are formed in the tread portion 12, so that ribs are formed from the inner side to the outer side in the tire width direction. 40, a middle land portion row 50, and both side land portion rows 60 are formed.

  In the intermediate land portion row 50 of this example, a plurality of inclined narrow grooves 34 that are connected to the circumferential main groove 20 and the circumferential main groove 22 and extend in an oblique direction intersecting the circumferential main grooves 20 and 22 are formed. . Thereby, in the intermediate land portion row 50 of this example, a plurality of intermediate land portions 51 are arranged along the tire circumferential direction.

  Here, when the length in the tire circumferential direction in which each intermediate land portion 51 is combined with one of the inclined narrow grooves 34 that divide each intermediate land portion 51 in the tire circumferential direction is defined as a pitch, the pneumatic tire 10 of the present example. Has a configuration with a plurality of pitches (three types of small, medium, and large in this example).

  That is, in the pneumatic tire 10 of this example, a so-called pitch variation is introduced into the pattern of the tread portion 12. For example, the middle land portion row 50 of this example includes the middle land portion 51 of the small pitch P1 and the middle pitch portion. A combination of the intermediate land portion 51 of P2 and the intermediate land portion 51 of the large pitch P3 is formed so as to be repeated in the tire circumferential direction.

  The combination of the intermediate land portion 51 of the small pitch P1, the intermediate land portion 51 of the medium pitch P2, and the intermediate land portion 51 of the large pitch P3 is not limited to this embodiment, and various modifications are made. Of course you can.

  For example, as in the present example, the combination of arrangement in ascending order from the intermediate land portion 51 of the small pitch P1 to the intermediate land portion 51 of the large pitch P3 is not repeated in the tire circumferential direction, but the intermediate land portion 51 having a small pitch. From the intermediate land portion 51 of the large pitch P3 to the intermediate land portion 51 of the large pitch P3 to the intermediate land portion 51 of the small pitch P1, and this combination is repeated in the tire circumferential direction. Also good.

  Further, the intermediate land portion 51 having the small pitch P1, the intermediate land portion 51 having the medium pitch P2, and the intermediate land portion 51 having the large pitch P3 may be randomly arranged in the tire circumferential direction.

  In each intermediate land portion 51, one lug groove 32 is formed along an oblique direction intersecting with the circumferential main groove 22. In this example, the lug grooves 32 are formed at variable intermediate pitches in the tire circumferential direction by forming the lug grooves 32 at intermediate positions in the tire circumferential direction of the intermediate land portions 51 into which the pitch variations are introduced.

  As will be described in detail later, the lug groove 32 is provided to reduce air column resonance generated in the circumferential main groove 22, and one end in the groove longitudinal direction is formed in the circumferential main groove 22. While being connected and opened, the other end in the longitudinal direction of the groove is configured to terminate in the intermediate land portion 51. Further, as shown in FIG. 2, the lug groove 32 of the present example is formed with a groove depth shallower than the adjacent circumferential main groove 22.

  And in the pneumatic tire 10 of this example, it is comprised so that the groove volume of the lug groove 32 may become two or more types about the circumferential direction main groove 22 in a tire contact surface. At this time, in this example, as the pitch of each intermediate land portion 51 increases, the groove volume of the lug groove 32 increases. More specifically, the pitch of each intermediate land portion 51 increases. Accordingly, the groove length in the groove longitudinal direction of the lug groove 32 is increased.

  In this case, the tire contact surface means that the pneumatic tire 10 is mounted on a standard rim defined in JATMA YEAR BOOK (2004 edition, Japan Automobile Tire Association Standard) and applied size / ply in JATMA YEAR BOOK. This is when the maximum load capacity is loaded with 100% internal pressure of the air pressure (maximum air pressure) corresponding to the maximum load capacity in the rating (bold load in the internal pressure-load capacity correspondence table). When the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards are followed.

  Here, in this example, as the pitch of each intermediate land portion 51 increases, the length in the groove longitudinal direction of the lug groove 32 increases, but as the pitch of each intermediate land portion 51 increases, The groove depth or groove width of the lug groove 32 may be increased, or at least one of the length in the groove longitudinal direction, the groove depth, and the groove width may be increased. good.

  In the rib 40 of this example, a plurality of lug grooves 30 extending in an oblique direction intersecting with the circumferential main groove 20 are formed. Each lug groove 30 is disposed so as to be located on the extension line of the inclined narrow groove 34 and is disposed at a variable pitch in the tire circumferential direction, like the lug groove 32.

  The lug groove 30 is provided to reduce air column resonance generated in the circumferential main groove 20, and one end of the groove in the longitudinal direction is connected to the circumferential main groove 20 and opens. The other end in the longitudinal direction of the groove is configured to terminate in the rib 40. Further, as shown in FIG. 3, the lug groove 30 of the present example is formed with a groove depth shallower than the adjacent circumferential main groove 20.

  And in the pneumatic tire 10 of this example, it is comprised so that the groove volume of the lug groove 30 may become two or more types about the circumferential direction main groove 20 in a tire ground contact surface. At this time, in this example, it is configured such that the groove volume of the lug grooves 30 increases as the pitch between the lug grooves 30 increases, more specifically, as the pitch between the lug grooves 30 increases. The groove length in the groove longitudinal direction of the lug groove 30 is configured to increase.

  In this case, the tire contact surface is the same as described above, in which the pneumatic tire 10 is mounted on a standard rim defined in JATMA YEAR BOOK (2004 edition, Japan Automobile Tire Association Standard), and the JATMA YEAR BOOK is used. When the maximum load capacity is loaded, 100% of the air pressure (maximum air pressure) corresponding to the maximum load capacity (bold load in the internal pressure-load capacity correspondence table) is applied. When the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards are followed.

  Here, in this example, it has been described that the length in the longitudinal direction of the lug grooves 30 increases as the pitch between the lug grooves 30 increases. However, as the pitch between the lug grooves 30 increases, the lug grooves The groove depth or groove width of 30 may be increased, or at least one of the length in the longitudinal direction of the groove, the groove depth, and the groove width may be increased.

  In the both-side land section row 60 of this example, a plurality of inclined grooves 36 that are connected to the circumferential main groove 22 and extend in an oblique direction intersecting the circumferential main groove 22 are formed. Thereby, in the both-side land portion row 60 of this example, a plurality of both-side land portions 61 are arranged along the tire circumferential direction.

  The both-side land portions 61 of this example are formed in accordance with the pitches of the intermediate land portions 51, and concave portions 37 are formed at positions corresponding to the lug grooves 32 of the both-side land portions 61. Further, on the outer side in the tire width direction of the concave portion 37, an inclined narrow groove 38 extending from the concave portion 37 to the outer side in the tire radial direction and terminating in the both side land portions 61 is formed. On the extension line, an inclined narrow groove 39 extending from the tread end 14 side to the inner side in the tire radial direction and terminating in the land portions 61 on both sides is formed.

  Here, although not shown, left and right sidewalls are formed on both sides in the tire width direction of the tread 12 in the pneumatic tire 10 of this example, and carcass is provided on the inside of the sidewalls and the tread 12. It has been. Further, a belt is interposed between the tread 12 and the carcass. In addition, the pneumatic tire 10 of this example is provided with conventionally known members such as beads.

(Function and effect)
Next, the function and effect of the pneumatic tire having the above configuration will be described.

  In the pneumatic tire 10 of this example, a lug groove 32 is formed in each intermediate land portion 51 of the intermediate land portion row 50 along the direction intersecting with the circumferential main groove 22. Are connected to the circumferential main groove 22 and open, and the other end in the longitudinal direction of the groove is terminated in the intermediate land portion 51.

  In this way, when the lug groove 32 whose one side is closed like a bag is connected to the circumferential main groove 22, the sound pressure of the air column resonance generated in the circumferential main groove 22 can be reduced by the side branch effect. That is, when the lug groove 32 closed on one side in a bag shape is connected to the circumferential main groove 22, the length of the lug groove 32 in the longitudinal direction of the groove is L and the speed of sound is V. The air column resonance sound having the frequency f can be absorbed.

  f = (2n−1) · V / 4L (1)

Where n: vibration order (n = 1, 3, 5...)

  In this example, the groove volume (at least one of the groove length, groove depth, and groove width) of the lug groove 32 is at least two or more (three in this example) with respect to the circumferential main groove 22 in the tire contact surface. Therefore, the sound pressure reducing effect of the air column resonance generated in the circumferential main groove 22 can be varied (dispersed) depending on the groove volume of the lug groove 32.

  Further, in the intermediate land portion row 50 of this example, pitch variation is introduced into the tread pattern, so that air column resonance generated in the circumferential main groove 22 can be reduced.

  As described above, according to this example, pitch variation is introduced into the tread pattern, and the lug groove 32 whose one side is closed like a bag is connected to the circumferential main groove 22, and the groove volume of the lug groove 32 is adjusted to the tire contact. By using at least two types of circumferential main grooves 22 in the ground, noise caused by air column resonance in the circumferential main grooves 22, which is said to occupy a large weight in the noise of the pneumatic tire 10, can be effectively obtained. Can be reduced.

  In particular, in this example, since the length of the lug groove 32 in the longitudinal direction of the lug groove 32 is at least two or more with respect to the circumferential main groove 22 in the tire ground contact surface, the lug groove 32 is expressed by the above equation (1). The frequency f of the air column resonance sound that can be absorbed by the lag groove 32 can be varied (dispersed) depending on the length of the lug groove 32 in the groove longitudinal direction.

  Thereby, since the effect of reducing air column resonance generated in the circumferential main groove 22 can be enhanced as compared with the conventional case, the circumferential main groove 22 is said to occupy a large weight in the noise of the pneumatic tire 10. Noise caused by air column resonance can be more effectively reduced.

  Furthermore, in the pneumatic tire 10 of the present example, the lug groove 30 is formed in the rib 40 along the direction intersecting the circumferential main groove 20, and one end of the lug groove 30 in the longitudinal direction of the groove is the circumferential main. While being connected to the groove 20 and opening, the other end in the groove longitudinal direction is configured to terminate in the rib 40.

  In this way, when the lug groove 30 closed on one side in a bag shape is connected to the circumferential main groove 20, the sound pressure of the air column resonance generated in the circumferential main groove 20 is reduced by the side branch effect, similarly to the lug groove 32. Can be reduced.

  Further, in this example, the groove volume (at least one of the groove length, groove depth, and groove width) of the lug groove 30 is at least two or more (three in this example) with respect to the circumferential main groove 20 in the tire ground contact surface. Therefore, the effect of reducing the sound pressure of the air column resonance generated in the circumferential main groove 20 can be varied (dispersed) depending on the groove volume of the lug groove 30.

  In particular, in this example, since the length of the lug groove 30 in the longitudinal direction of the lug groove 30 is at least two kinds of the circumferential main groove 20 in the tire ground contact surface, the lug groove 30 is expressed by the above equation (1). The frequency f of the air column resonance sound that can be absorbed by the lag groove 30 can be varied (dispersed) depending on the length of the lug groove 30 in the groove longitudinal direction.

  Thereby, since the effect of reducing air column resonance generated in the circumferential main groove 20 can be enhanced as compared with the conventional case, the circumferential main groove 20 is said to occupy a large weight in the noise of the pneumatic tire 10. Noise caused by air column resonance can also be reduced more effectively.

(Test example)
Next, performance evaluation of the pneumatic tire 10 according to the present embodiment will be described.

  In order to confirm the effect of the present invention, a comparative test is performed on the pneumatic tire (two types) according to the conventional example and the pneumatic tire 10 according to the present example.

  The pneumatic tire according to Conventional Example 1 has a constant length and groove depth in the longitudinal direction of the lug grooves 30 and 32 formed in each intermediate land portion 51 with respect to the pneumatic tire 10 of the present embodiment, and The groove area ratio in the tire tread surface of the tread portion 12 is 35%, and other configurations are the same.

  The pneumatic tire according to Conventional Example 2 has a constant length and depth in the longitudinal direction of the lug grooves 30 and 32 formed in each land portion with respect to the pneumatic tire 10 of this embodiment, and the tread. The groove area ratio on the tire tread surface of the portion 12 is 30%, and the other configurations are the same.

  In the comparative test, a passing noise test and a cornering hydroplaning test are performed for each pneumatic tire. The pneumatic tire is 235 / 50R18, and the vehicle is a large-sized sedan type passenger car made in Japan. The pneumatic pressure of each pneumatic tire is 230 kpa, and vehicle conditions such as alignment are specified by the vehicle.

  In the passing noise test, measurement is performed based on a vehicle passing noise test method defined in JIS D8301. Specifically, the vehicle is run at 53 km / h on the ISO road surface, and the passing noise at this time is measured by a microphone placed 7.5 m away from the center of the vehicle and at a height of 1.2 m. The ISO road surface is a road surface for measuring vehicle passing noise defined in the ISO 10844 standard.

  In the cornering hydroplaning test, the vehicle's lateral acceleration when a 100m radius turn on a road surface with a water depth of 10mm and the speed gradually increases to cause the hydroplaning phenomenon and the turning of the 100m radius cannot be maintained. Measure.

  Table 1 shows the comparative test results together with the detailed configuration of the pneumatic tires according to Conventional Example 1, Conventional Example 2, and Examples.

  From the above tests, as shown in Table 1, the pneumatic tire of Conventional Example 2 can suppress the passing noise as compared with the pneumatic tire of Conventional Example 1, but the wet performance is inferior. Obtained.

  On the other hand, the pneumatic tire 10 of the present embodiment can suppress the passing noise as low as the pneumatic tire according to the conventional example 2 while ensuring the wet performance equivalent to that of the pneumatic tire according to the conventional example 1. The result that it was possible was obtained.

  From the above, it can be said that the pneumatic tire 10 of the present example is a well-balanced pneumatic tire having both wet performance and low noise performance.

FIG. 1 is a developed view of a tread portion of a pneumatic tire according to the present embodiment. FIG. 2 is a cross-sectional view of a main part of the tread portion according to the present embodiment. FIG. 3 is a cross-sectional view of the main part of the tread portion according to the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Tread part 20,22 Circumferential main groove 24 Circumferential narrow groove (lateral groove)
30, 32 Lug groove 40 Rib 50 Middle land part 51 Middle land part

Claims (5)

At least one circumferential main groove is formed along the tire circumferential direction on the tire tread surface of the tread portion, and a plurality of lateral grooves are formed crossing the circumferential main groove, thereby forming a tire circumferential direction. A plurality of land portions are arranged, and the pitch in the tire circumferential direction combined with each land portion and one of the lateral grooves that divide each land portion in the tire circumferential direction is a plurality of pitches. In a pneumatic tire comprising:
Each land part is formed with at least one lug groove along a direction intersecting the circumferential main groove,
The lug groove is configured such that one end portion in the groove longitudinal direction is connected to the circumferential main groove to open, and the other end portion in the groove longitudinal direction is terminated in each land portion.
The pneumatic tire according to claim 1, wherein a groove volume of the lug groove is at least two kinds with respect to the circumferential main groove.   2. The pneumatic tire according to claim 1, wherein the length of the lug groove in the longitudinal direction of the groove is at least two kinds with respect to the circumferential main groove.   3. The pneumatic tire according to claim 1, wherein the groove depth of the lug groove is at least two kinds of the circumferential main groove.   The pneumatic tire according to any one of claims 1 to 3, wherein the groove width of the lug groove is at least two kinds with respect to the circumferential main groove.   The pneumatic tire according to any one of claims 1 to 4, wherein the lug groove is configured such that the groove volume increases as the pitch increases.

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