JP5346663B2 - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire for easily ejecting a stone even when the stone is bitten into a resonance groove that eliminates an air column resonance. <P>SOLUTION: The pneumatic tire 1 includes: circumferential grooves 10 and 11 extending in a circumferential direction of a tire; an L-shaped resonance groove 20 having one end 20a connected to the circumferential groove 11 and the other end 20b ending in a land part 12; and a striation 30 extending from the other end 20b of the L-shaped resonance groove 20 to the circumferential groove 11 along a tire width direction. The circumferential groove 11, the resonance groove 20 and the striation 30 define a block 40 on a tread surface 53. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire in which stone engagement of a resonance groove provided on a tread surface is reduced.

  Conventionally, air columnar resonance generated when the tread surface of a tire contacts the road surface when the vehicle is running has been a problem. This air columnar resonance sound is generated when the tire tread surface contacts the road surface and the circumferential groove of the tire becomes a thin tube, and the air inside is rapidly compressed and goes out at once. In order to reduce the air column resonance noise, a technique of forming a side branch type resonance groove on the tread surface is known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2006-1312

  In the conventional air columnar resonance, it is necessary to adjust the length of the resonance groove in order to resonate at a predetermined frequency, and the groove is generally set to a circumferential groove extending in the circumferential direction. . However, since the circumferential groove is less deformed when the tire is depressed than the lateral groove, there is a problem that the circumferential groove is difficult to be discharged when a stone is caught.

  An object of the present invention is to provide a pneumatic tire in which stones are easily discharged even when stones are caught in resonance grooves that reduce air column resonance noise.

  The first feature of the present invention is that a circumferential groove (circumferential grooves 10, 11) extending in the tire circumferential direction and one end (one end 20a) communicate with the circumferential groove and the other end (other end 20b) is land. A resonance groove (L-shaped resonance groove 20) closed within the portion (land portion 12), and a narrow groove (narrow groove 30) extending along the tire width direction from the other end of the resonance groove to the circumferential groove A pneumatic tire (pneumatic tire 1) in which a block (blocks 40, 240, 340) is defined on a tread surface (tread surface 53) by the circumferential groove, the resonance groove, and the narrow groove. The gist.

  Thus, by making the resonance groove into a block, the rigidity of the land portion can be reduced, and when the pneumatic tire is stepped on, the block can be elastically deformed so that stones caught in the resonance groove can be easily discharged. Further, by extending the narrow groove along the tire width direction, the narrow groove is closed when the tire is stepped on, and the resonance groove acts effectively, so that stones caught in the resonance groove can be easily discharged.

  Another feature of the present invention is that the radial direction of the longitudinal wall surface (vertical wall surface 150) of the circumferential groove (end-side circumferential groove 11) corresponding to the portion defining the block (blocks 40, 240, 340) is the tire radial direction. The gist is that the inclination angle (inclination angle θ1) with respect to is set smaller than the inclination angle (inclination angle θ0) with respect to the tire radial direction of the vertical wall surfaces (vertical wall surfaces 51 and 52) of the circumferential grooves in other portions.

  Another feature of the present invention is that a tapered portion (tapered portion 200, 300) is provided along the tire circumferential direction at the upper end corner located on the resonance groove side in the block (block 240, 340) and on the outer side in the tire radial direction. The gist is the formation.

  Another feature of the present invention is that a taper portion (gradual change taper portion 300) is formed at an upper end corner located on the circumferential groove side in the block (block 340) and on the outer side in the tire radial direction. .

  Another feature of the present invention is that the tapered portion of the upper end corner extends from the other end (20b) side to the one end (20a) side of the resonance groove (L-shaped resonance groove 20) along the tire circumferential direction. The gist is that it is formed in a gradually changing taper portion (gradually changing taper portion 300) whose size gradually changes.

  According to the pneumatic tire according to the present invention, when the tire is stepped on, the block can be elastically deformed to easily discharge the stones biting into the resonance groove.

It is sectional drawing of the width direction of the pneumatic tire by this invention. It is an enlarged view of the resonance groove | channel by 1st Embodiment of this invention. (A) is sectional drawing by the AA line and CC line of FIG. 2, (b) is sectional drawing by the BB line of FIG. It is an enlarged view of the resonance groove | channel by 2nd Embodiment of this invention. (A) is sectional drawing by the DD line and FF line of FIG. 4, (b) is sectional drawing by the EE line of FIG. It is an enlarged view of the resonance groove | channel by 3rd Embodiment of this invention. It is sectional drawing by the GG line of FIG. It is an enlarged view of the resonance groove | channel by 4th Embodiment of this invention. (A) is sectional drawing by the HH line | wire of FIG. 8, (b) is sectional drawing by the II line | wire of FIG. FIG. 6 is an enlarged view of a resonance groove according to another embodiment of the present invention. It is an enlarged view of the resonance groove | channel which concerns on the prior art example in an Example.

  Hereinafter, details of a pneumatic tire according to an embodiment of the present invention will be described with reference to the drawings. However, it should be noted that the drawings are schematic, and the thicknesses and ratios of the material layers are different from actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

  FIG. 1 is a cross-sectional view in the width direction of a pneumatic tire according to an embodiment of the present invention.

  The pneumatic tire 1 includes a pair of annular bead cores 2 and 2 that are spaced apart from each other in the tire width direction, a carcass 3 that is a skeleton of a tire that connects these bead cores 2 and 2 in a toroidal shape, and a carcass 3 And two belt layers 4 disposed on the crown portion 3a disposed at the center in the width direction.

  Further, a crown portion 3a of the carcass 3, a belt layer 4 and a tread portion 5 made of a tread rubber covering these are formed at the center in the width direction of the pneumatic tire 1, and on the left and right sides of the tread portion 5, Sidewall portions 6 and 6 are provided, and a bead portion 7 is formed in the vicinity of the bead core 2 on the inner diameter side of the sidewall portion 6. And the carcass 3 has the folding | returning part 3b which winds the bead core 2 from the tire width direction inner side, and folds back and extends to a radial outward direction. The belt layer 4 is composed of an inner belt 8 having a large width dimension in the tire width direction and an outer belt 9 disposed on the outer diameter side of the inner belt 8. Further, circumferential grooves 10 and 11 extending in the tire circumferential direction are formed on the surface of the tread portion 5.

[First embodiment]
First, a first embodiment of the present invention will be described.

  FIG. 2 is an enlarged view of the resonance groove according to the first embodiment of the present invention. 3A is a cross-sectional view taken along line AA and CC in FIG. 2, and FIG. 3B is a cross-sectional view taken along line BB in FIG.

  As shown in FIG. 2, a central circumferential groove 10 extends along the tire circumferential direction on the center side in the tire width direction, and an end side circumferential groove 11 is on the end side in the tire width direction. It extends along the circumferential direction. A land portion 12 is formed between the center-side circumferential groove 10 and the end-side circumferential groove 11, and an L-shaped resonance groove 20 and a narrow groove 30 are disposed on the land portion 12. Yes. A block 40 having a rectangular shape in plan view is defined by the end-side circumferential groove 11, the L-shaped resonance groove 20, and the narrow groove 30.

  One end 20 a of the L-shaped resonance groove 20 communicates with the end-side circumferential groove 11, and the other end 20 b is closed within the land portion 12. Specifically, the L-shaped resonance groove 20 is integrally formed in an L shape from a lateral groove portion 21 extending in the tire width direction and a longitudinal groove portion 22 extending from the end 21a of the lateral groove portion 21 in the tire circumferential direction. .

  Further, the other end 20 b of the L-shaped resonance groove 20 and the end-side circumferential groove 11 are connected by a narrow groove 30. That is, both end portions of the narrow groove 30 are formed in the resonance groove side end portion 30 a and the circumferential groove side end portion 30 b, and the resonance groove side end portion 30 a communicates with the other end 20 b of the L-shaped resonance groove 20. The circumferential groove side end 30 b communicates with the end side circumferential groove 11. The narrow groove 30 extends along the tire width direction (perpendicular to the tire circumferential direction).

  As shown in FIGS. 3A and 3B, the vertical wall surface on the center side in the tire width direction in the end-side circumferential groove 11 in FIG. 2 is inclined with respect to the tire radial direction between the side surface of the block 40 and other portions. The corners are set to the same corner. That is, as shown in FIG. 3B, the inclination angle at which the vertical wall surface 50 of the end side circumferential groove 11 defining the side surface of the block 40 is inclined with respect to the tire radial direction is θ0. On the other hand, as shown in FIG. 3A, the vertical wall surface 51 of the end-side circumferential groove 11 at the position closer to the narrow groove 30 than the block 40 and the lateral groove 21 side from the block 40. An inclination angle at which the vertical wall surface 52 of the end-side circumferential groove 11 at the close position is inclined with respect to the tire radial direction is also θ0. Thus, the inclination angles of the vertical wall surfaces 50 to 52 are both set to be the same as θ0. In FIG. 3, 53 is a tread surface, and 54 is a groove bottom.

  The effect by this embodiment is demonstrated.

(1) In the pneumatic tire 1 according to the present embodiment, the circumferential grooves 10 and 11 extending in the tire circumferential direction, one end 20a communicates with the circumferential groove 11, and the other end 20b is closed within the land portion 12. An L-shaped resonance groove 20 and a narrow groove 30 extending along the tire width direction from the other end 20b of the L-shaped resonance groove 20 to the circumferential groove 11 are provided. The circumferential groove 11, the resonance groove 20 and the narrow groove are provided. A block 40 is defined on the tread surface 53 by the groove 30.

  In this way, the L-shaped resonance groove 20 is blocked to reduce the rigidity of the land portion, and when the tire is stepped on, the block 40 is elastically deformed to discharge the stone caught in the L-shaped resonance groove 20. Can be made easier. Further, by extending the narrow groove 30 along the tire width direction, the narrow groove 30 is closed when the tire is depressed, and the L-shaped resonance groove 20 effectively acts as the resonance groove. It is easy to discharge the stones biting into.

[Second Embodiment]
Next, a second embodiment of the present invention will be described, but the same reference numerals are given to portions having the same structure as the first embodiment described above, and the description will be omitted. FIG. 4 is an enlarged view of a resonance groove according to the second embodiment of the present invention. 5A is a cross-sectional view taken along line DD and FF in FIG. 4, and FIG. 5B is a cross-sectional view taken along line EE in FIG. 4.

  As shown in FIG. 4, a block 40 having a rectangular shape in plan view is defined by the end side circumferential groove 11, the L-shaped resonance groove 20, and the narrow groove 30.

  As shown in FIGS. 5 (a) and 5 (b), the vertical wall surface on the tire width direction center side in the end side circumferential groove 11 in FIG. 4 is inclined with respect to the tire radial direction between the side surface of the block 40 and other portions. The corners are different.

  Specifically, as shown in FIG. 5B, the inclination angle of the longitudinal wall surface 150 of the end-side circumferential groove 11 corresponding to the portion defining the block 40 with respect to the tire radial direction is θ1, and FIG. As shown in a), the inclination angle with respect to the tire radial direction of the longitudinal wall surfaces 51 and 52 of the end-side circumferential groove 11 at a portion other than the block 40 is θ0, and the inclination angle θ1 is set smaller than the inclination angle θ0. doing.

  The effect by this embodiment is demonstrated.

(1) The inclination angle θ1 with respect to the tire radial direction of the vertical wall surface 150 of the end side circumferential groove 11 corresponding to the site defining the block 40 is set to the vertical wall surface 51 of the end side circumferential groove 11 in the other site. 52 is set to be smaller than the inclination angle θ0 with respect to the tire radial direction.

  As a result, the rigidity of the block 40 is further reduced, and when the tire is stepped on, the block 40 is elastically deformed to easily fall down, and the stone caught in the L-shaped resonance groove 20 can be more easily discharged. .

[Third embodiment]
Next, a third embodiment of the present invention will be described, but the same reference numerals are given to the parts having the same structure as the first and second embodiments described above, and the description will be omitted.

  FIG. 6 is an enlarged view of a resonance groove according to the third embodiment of the present invention. 7 is a cross-sectional view taken along line GG in FIG.

  As shown in FIGS. 6 and 7, a tapered portion 200 is formed in a portion of the upper end corner portion of the block 240 facing the longitudinal groove portion 22 of the L-shaped resonance groove 20. The tapered portion 200 is formed in substantially the same size along the tire circumferential direction.

  The effect by this embodiment is demonstrated.

(1) The taper part 200 is formed in the upper end corner | angular part which is the L-shaped resonance groove 20 side in the block 240, and is located outside a tire radial direction. The taper portion 200 further reduces the rigidity of the block 240, and when the tire is stepped on, the block 240 is elastically deformed so that the block 240 is easily collapsed, and the stone caught in the L-shaped resonance groove 20 is more easily discharged. Can do.

[Fourth embodiment]
Next, a fourth embodiment of the present invention will be described, but the same reference numerals are given to the parts having the same structure as the first to third embodiments described above, and the description will be omitted. FIG. 8 is an enlarged view of a resonance groove according to the fourth embodiment of the present invention. 9A is a cross-sectional view taken along line H-H in FIG. 8, and FIG. 9B is a cross-sectional view taken along line I-I in FIG. 8.

  As shown in FIGS. 8 and 9, a taper portion is formed in both the longitudinal groove portion of the L-shaped resonance groove 20 and the portion facing the circumferential groove in the upper end corner portion of the block 340. The tapered portion is a gradually changing tapered portion 300 whose size gradually changes along the tire circumferential direction. Specifically, the gradually changing taper portion 300 is formed such that the taper amount on the narrow groove side is small and the taper amount gradually increases toward the lateral groove portion 21 side of the L-shaped resonance groove 20.

  The effect by this embodiment is demonstrated.

(1) An L-shape is formed along the tire circumferential direction at the upper end corner located on the end side circumferential groove 11 side in the block 340 and on the outer side in the tire radial direction and the upper end corner on the L-shaped resonance groove 20 side. A gradual change taper portion 300 that gradually changes in size from the other end 20b side to the one end 20a side of the resonance groove 20 is formed. Here, since the block rigidity of the one end side of the L-shaped resonance groove 20 is lower than that of the other end side, the block 340 is more easily collapsed by further reducing the rigidity of the low rigidity portion, so Emission performance is improved. Moreover, since the gradually changing taper portion 300 becomes larger as the block 340 moves toward the one end 20a, the stones biting into the grooves are easily discharged.

  It should not be understood that the description and the drawings, which form part of the disclosure of the above-described embodiments, limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the first to fourth embodiments, the resonance groove is formed in an L shape in plan view, but a resonance groove as shown in FIG. 10 may be used. The resonance groove 400 is formed to be slightly curved along the tire circumferential direction, with one end 400 a communicating with the end side circumferential groove 11 and the other end 400 b closed within the land portion 12.

    In the first to fourth embodiments, one end of the L-shaped resonance groove communicates with the end-side circumferential groove 11, but one end of the L-shaped resonance groove is formed in the center-side circumferential groove 10. You may make it communicate.

  Next, the present invention will be described more specifically through examples.

  A pneumatic tire having a size of 215 / 60R16 was used as a test tire according to a conventional example and Examples 1-4 of the present invention.

  As shown in FIG. 11, the test tire according to the conventional example is formed with circumferential grooves 10, 11 extending in the tire circumferential direction, one end 500a communicating with the circumferential groove 11, and the other end 500b being land. An L-shaped resonance groove 500 closed within the portion 12 is formed. The L-shaped resonance groove 500 is integrally formed from the horizontal groove portion 521 and the vertical groove portion 522, and no narrow groove is formed as in the present invention example.

Moreover, each groove dimension etc. which concern on a prior art example and this invention examples 1-4 are as showing in following Table 1. FIG. In Table 1, the inclination angle of the groove wall corresponding to the part other than the block means the inclination angle shown in FIG. The inclination angle shown in (b) is meant.

  These test tires were mounted on a rim having a size of 7 J × 16 inches, and then mounted on a vehicle (Crown manufactured by Toyota Motor Corporation) on which two people got on with an internal pressure of 220 kPa. This vehicle was covered with stones and gravel with a diameter of about 1 mm to 10 mm, and made two rounds of an unpaved road of about 300 m including a straight road and a cornering road. Thereafter, the vehicle traveled about 2000 m on a smooth paved road (circumferential circuit including a straight road and a cornering road) in which stones and gravel are not scattered on the road, and the number of stones remaining in the L-shaped groove was counted. The average remaining number of the four front and rear wheels was indexed and compared with the conventional number as 100.

  As a result, the stone biting property was 100 for the conventional example, 65 for the inventive example 1, 50 for the inventive example 2, 25 for the inventive example 3, and 20 for the inventive example 4. As described above, it was found that the pneumatic tires according to Examples 1 to 4 of the present invention have better exhaustability of the stones bitten than the conventional examples.

10,11 Circumferential groove 20 L-shaped resonance groove (resonance groove)
30 Narrow groove 200 Tapered part 300 Gradual change taper part (taper part)

Claims (4)

A circumferential groove extending in the tire circumferential direction;
A resonance groove with one end communicating with the circumferential groove and the other end closed within the land;
A narrow groove extending along the tire width direction from the other end of the resonance groove to the circumferential groove,
A block is defined on the tread surface by the circumferential groove, the resonance groove and the narrow groove ,
A pneumatic tire characterized in that a taper portion is formed along the tire circumferential direction at an upper end corner located on the resonance groove side in the block and on the outer side in the tire radial direction .   The inclination angle of the vertical wall surface of the circumferential groove corresponding to the part defining the block with respect to the tire radial direction is set smaller than the inclination angle of the vertical wall surface of the circumferential groove with respect to the tire radial direction in the other part. The pneumatic tire according to claim 1. 3. The pneumatic tire according to claim 1, wherein a tapered portion is formed at an upper end corner located on the circumferential groove side in the block and on the outer side in the tire radial direction. The tapered portion of the upper end corner portion is formed as a gradually changing taper portion whose size gradually changes from the other end side to the one end side of the resonance groove along the tire circumferential direction. The pneumatic tire according to 1 or 3 .

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