JP5400492B2 - tire - Google Patents

Description

  According to the present invention, a plurality of rib-like land portions defined by a plurality of circumferential grooves extending along the tire circumferential direction are recessed toward the inner side in the tire radial direction. The present invention relates to a tire provided with a resonator that forms a space and communicates with the circumferential groove.

  Conventionally, in a tire mounted on a passenger car or the like, various methods of reducing air column resonance noise caused by a space formed by a circumferential groove extending along the tire circumferential direction and a road surface have been realized. For example, the tread forms a certain space by contacting with the road surface, and includes a longitudinal groove extending along the tire circumferential direction, and a lateral groove that communicates with the longitudinal groove and the circumferential groove and extends along the tread width direction. A tire in which a branch type resonator is provided in a rib-like land portion extending along the tire circumferential direction is known (for example, Patent Document 1).

JP 2008-302898 A (page 3-4, FIG. 1)

  By the way, in recent years, in passenger cars and the like, there has been an increasing demand for reducing tire noise due to further progress in reducing vehicle noise (wind noise, mechanical noise, etc.) and further consideration for the environment. It is growing.

  Of the tire noise, passing noise caused by air column resonance noise generally has a volume level peak around 1 kHz. When the side branch type resonator is used to reduce the passing noise having such characteristics, there are the following problems.

  That is, the side branch type resonator needs to change its volume according to the resonance frequency band, but if the resonance frequency band is set to around 1 kHz, the volume of the side branch type resonator increases, It is difficult to ensure block rigidity.

  Therefore, in the case where a resonator that forms a certain space by contacting with the road surface is provided in the rib-like land portion, the present invention secures the block rigidity of the rib-like land portion and suppresses tire noise, particularly passing noise. A further object is to provide a reduced tire.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that a plurality of rib-shaped land portions (for example, rib-shaped land portions 110) partitioned by a plurality of circumferential grooves (for example, the circumferential grooves 11) extending along the tire circumferential direction. And a resonator (for example, resonator R1) that is recessed toward the inner side in the tire radial direction, forms a predetermined space by the rib-shaped land portion contacting the road surface (road surface RS), and communicates with the circumferential groove. And the first resonator (resonator R1 and resonator R2) provided in the tire circumferential direction, and the first resonator. And a plurality of second resonators (resonators R3 to R8) that are provided on the inner side when the vehicle is mounted and are provided along the tire circumferential direction. The first resonator is recessed toward the inner side in the tire radial direction. An air chamber (for example, air chamber 130A) and the air chamber And a narrow groove portion (for example, the narrow groove portion 121) communicating with the circumferential groove, the second resonator includes a longitudinal groove (longitudinal groove 184) extending along the tire circumferential direction. , A side branch type resonator having a lateral groove (for example, a lateral groove 182) that communicates with the longitudinal groove and the circumferential groove and extends along the tread width direction, and the volume of the first resonator is the second resonator. The gist is that it is larger than the volume of the resonator.

  According to such a tire, since the first resonator is a Helmholtz type resonator, the volume of the first resonator can be made smaller than that of the side branch type resonator. Thereby, the 1st resonator can ensure the block rigidity of the rib-shaped land part in which a 1st resonator is provided rather than a side branch type resonator.

  In addition, since the first resonator is located on the outer side when the vehicle is mounted than the second resonator, it is possible to effectively reduce outside noise such as passing noise that is easily transmitted outward from the vehicle on which the tire is mounted. In particular, since the first resonator is a Helmholtz type resonator, the vehicle exterior noise having a volume level peak around 1 kHz, such as passing noise caused by air column resonance, is more effective than the side branch type resonator. Can be reduced.

  In addition, the first resonator is a Helmholtz resonator, and the volume of the first resonator is larger than the volume of the second resonator, so that the peak of outside noise can be effectively reduced.

  On the other hand, since a plurality of second resonators are provided along the tire circumferential direction and each of the second resonators is a side branch type resonator having a small volume, the block rigidity of the rib-like land portion is appropriately reduced. As a result, road noise transmitted through the interior of the vehicle by transmitting the suspension, the body, and the like can also be suppressed. In particular, road noise is likely to be transmitted from the inner part of the tire near the suspension or axle when the vehicle is mounted. Therefore, providing the second resonator having a small volume on the inner side of the vehicle effectively reduces the road noise generated from the part. Can be reduced.

  That is, according to such a tire, tire noise, particularly passing noise can be further reduced while ensuring the block rigidity of the rib-like land portion.

  The second feature of the present invention relates to the first feature of the present invention, and is summarized in that the number of the second resonators is larger than the number of the first resonators.

  A third feature of the present invention relates to the first or second feature of the present invention, wherein the length of the first resonator along the tire circumferential direction is the length of the second resonator along the tire circumferential direction. The gist is that it is longer than this.

  A fourth feature of the present invention relates to any one of the first to third features of the present invention, wherein the longitudinal groove and the lateral groove have substantially the same groove width, and are larger than the groove width of the circumferential groove. The gist is thin.

  A fifth feature of the present invention is according to any one of the first to fourth features of the present invention, wherein the rib-like land portion is in contact with the road surface to the bottom surface of the vertical and horizontal grooves. The gutter depth is substantially the same, and is summarized as being shallower than the circumferential groove depth from the grounding surface to the bottom surface of the circumferential groove.

  A sixth feature of the present invention relates to any one of the first to fifth features of the present invention, wherein the first resonator is based on a tire equator line (tire equator line CL) passing through the center in the tread width direction. As described above, the second resonator is provided on the first rib-shaped land portion (rib-shaped land portion 110) located on the outer side when the vehicle is mounted, and the second resonator is located on the inner side when the vehicle is mounted with respect to the tire equator line. The gist is to be provided in the rib-shaped land portion (rib-shaped land portion 210, rib-shaped land portion 240).

  A seventh feature of the present invention relates to any one of the first to sixth features of the present invention, wherein the number of the second resonators located on the ground contact surface in a state where a normal load is applied to the tire. Is summarized as being larger than the number of the first resonators.

  According to the characteristics of the present invention, when a resonator that forms a certain space by contacting with the road surface is provided in the rib-like land portion, tire noise, particularly, passage is ensured while ensuring the block rigidity of the rib-like land portion. A tire with further reduced noise can be provided.

It is a partial development view of the tread pattern of the tire concerning the embodiment of the present invention. It is a partial perspective view of the rib-shaped land part 110 which concerns on embodiment of this invention. It is a figure which shows the shape of resonator R1 in tread width direction view. It is a partial perspective view of the rib-like land part 210 and the rib-like land part 240 which concern on embodiment of this invention. It is a partial front view of the tire which concerns on the modification of embodiment of this invention. It is a graph which shows the result of the test concerning the comparative evaluation of the present invention.

  Next, an embodiment of a tire according to the present invention will be described with reference to the drawings. Specifically, (1) overall schematic configuration of tire, (2) shape of rib-like land, (3) modification, (4) comparative evaluation, (5) action / effect, and (6) other implementations A form is demonstrated.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(1) Overall Schematic Configuration of Tire FIG. 1 is a partial front view of a pneumatic tire 10 according to an embodiment of the present invention. The pneumatic tire 10 is a tire that is designed to reduce tire noise such as air columnar resonance and is mounted on a passenger car or the like that requires high silence. The pneumatic tire 10 may be filled with an inert gas such as nitrogen gas instead of air.

  A plurality of circumferential grooves are formed in the pneumatic tire 10. Specifically, circumferential grooves 11, 12, 21 and 22 are formed in the pneumatic tire 10. The circumferential grooves 11, 12, 21, and 22 extend along the tire circumferential direction (direction D1 in FIG. 1). Further, the pneumatic tire 10 is provided with a plurality of rib-like land portions 110, 210, and 240 partitioned by the circumferential grooves 11, 12, 21, and 22.

  Specifically, the rib-like land portion 110 is provided adjacent to the circumferential groove 11 and the circumferential groove 12 between the circumferential groove 11 and the circumferential groove 12. The rib-shaped land portion 110 extends along the tire circumferential direction. The rib-like land portion 110 is provided on the outer side (hereinafter referred to as the vehicle mounting outer side) when the pneumatic tire 10 is mounted on the vehicle with the tire equator line CL as a reference.

  The rib-like land portion 210 is provided adjacent to the circumferential groove 12 and the circumferential groove 21 between the circumferential groove 12 and the circumferential groove 21. The rib-like land portion 240 is provided adjacent to the circumferential groove 21 and the circumferential groove 22 between the circumferential groove 21 and the circumferential groove 22. The rib-like land portion 210 and the rib-like land portion 240 extend along the tire circumferential direction. The rib-shaped land portion 210 and the rib-shaped land portion 240 are provided on the inner side (hereinafter referred to as the vehicle mounting inner side) when the pneumatic tire 10 is mounted on the vehicle with reference to the tire equator line CL. The rib-like land portion 210 is not necessarily provided on the inner side when the vehicle is mounted than the tire equator line CL, and may be provided on the inner side when the vehicle is mounted than the rib-like land portion 110.

The pneumatic tire 10 is provided with a resonator that is recessed toward the inside in the tire radial direction and that forms a predetermined space when the rib-like land portion contacts the road surface.
(2) Shape of rib-like land portion Next, the shape of the rib-like land portion will be described. Specifically, the shape of the rib-like land portion 110 and the rib-like land portions 210 and 240 will be described.

(2.1) Rib-shaped land portion 110
FIG. 2 is a partial perspective view of the rib-like land portion 110 according to the embodiment of the present invention. FIG. 3 shows the shape of the resonator R1 formed by the pneumatic tire 10 and the road surface RS. Specifically, FIG. 3 is a diagram illustrating the shape of the resonator R1 when viewed in the tread width direction. Further, the region surrounded by the alternate long and short dash line in FIG.

  As shown in FIG. 2, the rib-shaped land portion 110 includes a land portion 120 </ b> A, a land portion 120 </ b> B, and a land portion 140. The land portion 120A, the land portion 120B, and the land portion 140 are in contact with the road surface RS as the pneumatic tire 10 rolls. That is, the land portion 120A, the land portion 120B, and the land portion 140 constitute a contact surface of the pneumatic tire 10 that contacts the road surface RS.

  The land portion 120A and the land portion 120B are provided at both ends of the rib-like land portion 110 in the tread width direction (direction D2 in FIG. 1). The land portion 120 </ b> A is adjacent to the circumferential groove 11. The land portion 120 </ b> B is adjacent to the circumferential groove 12.

  As shown in FIGS. 2 and 3, the rib-shaped land portion 110 is recessed toward the inside in the tire radial direction, and the resonator R1 and the resonator that form a predetermined space by the rib-shaped land portion 110 being in contact with the road surface. R2 is provided. The resonator R1 and the resonator R2 constitute a first resonator. A plurality of resonators R1 and R2 are Helmholtz resonators that are provided along the tire circumferential direction and include an air chamber portion and a narrowed groove portion.

  Specifically, the rib-like land portion 110 is located on the outer side in the tread width direction and communicates with the circumferential groove 11 and the resonator located on the inner side in the tread width direction and communicates with the circumferential groove 12. R2 is formed. Since the resonator R2 is substantially the same as the resonator R1 except that the resonator R2 is provided between the land portion 120B and the land portion 140 in the tread width direction and communicates with the circumferential groove 12, the resonator R1 is hereinafter referred to as the resonator R1. Is mainly described.

  The resonator R1 includes an air chamber part 130A and a constricted groove part 121. The air chamber portion 130A is an air chamber communicating with the narrowed groove portion 121, and includes a recessed portion 131 that is recessed toward the inner side in the tire radial direction. The air chamber portion 130A is provided between the land portion 120A and the land portion 140 in the tread width direction. Specifically, the air chamber portion 130 </ b> A is provided in the central portion Pc of the rib-like land portion 110 in the tread width direction. The air chamber portion 130A is repeated at a predetermined interval P along the tire circumferential direction. A height H from the bottom surface 132 of the air chamber portion 130A to the ground contact surface (for example, the surface of the land portion 120A that contacts the road surface RS) varies along the tire circumferential direction. The center CT1 of the arc of the bottom surface 132 is located on the inner side in the tire radial direction than the bottom surface 132. The bottom surface 132 contacts the road surface RS at the highest position 132a having the highest height to the ground contact surface. Specifically, the bottom surface 132 is in line contact with the road surface RS along a direction different from the tire circumferential direction. That is, the bottom surface 132 has such a shape that the width along the tire circumferential direction of the bottom surface 132 in contact with the road surface RS is as small as possible. The air chamber portion 130A is formed by a bottom surface 132 between two highest positions 132a adjacent in the tire circumferential direction and a road surface RS in contact with the land portion 120A and the land portion 140.

  The shape of the bottom surface of the air chamber portion 130B included in the resonator R2 is the same as the shape of the bottom surface 132, but the highest position 132a of the bottom surface 132 of the air chamber portion 130A and the highest position 132a of the bottom surface of the air chamber portion 130B. Are half-phase shifted by a distance P in the tire circumferential direction.

  As shown in FIG. 3, the bottom surface 132 of the air chamber portion 130 </ b> A repeats an arch shape that forms an arc in a cross-sectional view along the tire circumferential direction.

  The narrowed groove 121 is formed in the land 120 </ b> A and communicates with the air chamber 130 </ b> A and the circumferential groove 11. Specifically, the narrowing groove 121 is provided in the shoulder portion Ps located on the vehicle mounting outer side than the central portion Pc of the rib-like land portion 110. The narrowed groove 121 communicates with the air chamber 130A. The groove width of the narrowed groove 121 is about several mm. The volume of the space formed by the narrowed groove 121 and the road surface RS is smaller than the volume of the space formed by the air chamber 130A and the road surface.

  An end 121a, which is one end of the narrowed groove 121, communicates with a closed space formed by the air chamber 130A and the road surface RS. Specifically, the end 121a communicates with a closed space formed by the recessed portion 131, the highest positions 132a formed at both ends of the recessed portion 131 in the tire circumferential direction, and the road surface RS.

  On the other hand, the end 121 b that is the other end of the narrowed groove 121 communicates with at least one of the plurality of circumferential grooves, specifically, the circumferential groove 11. The end portion 121a communicates with the air chamber portion 130A at the lowest position 132b where the bottom surface 132 is lowest. For this reason, the resonator R <b> 1 has a shape that opens only in the circumferential groove 11.

  A narrow groove 122 is formed in the land portion 120A. The groove width of the narrow groove 122 is about several mm. The narrow groove 122 communicates only with the circumferential groove 11. That is, the narrow groove 122 does not communicate with the air chamber portion 130A. For this reason, the narrow groove 122 is not a component of the resonator R1.

(2.2) Rib-shaped land portions 210 and 240
FIG. 4 is a partial perspective view of the rib-like land portion 210 and the rib-like land portion 240 according to the embodiment of the present invention.

  As shown in FIG. 4, the rib-shaped land portion 210 has a land portion 211. The rib-shaped land portion 240 has a land portion 241. The land portion 211 of the rib-shaped land portion 210 is provided with resonators R3, R4, and R5 that are recessed toward the inner side in the tire radial direction and that form a predetermined space when the rib-shaped land portion 210 contacts the road surface. Similarly, the land portion 241 of the rib-like land portion 240 is provided with resonators R6, R7, and R8. The resonators R3 to R8 constitute a second resonator. The resonators R3 to R8 are located on the inner side when the vehicle is mounted than the resonators R1 and R2, and a plurality of the resonators are provided along the tire circumferential direction. Since the resonators R6 to R8 have the same configuration as the resonators R3 to R5, the resonators R3 to R5 will be mainly described below.

  The resonator R <b> 3 is a side branch type resonator having a lateral groove 182, a longitudinal groove 184, and a lateral groove 186. The longitudinal groove 184 extends along the tire circumferential direction. The lateral groove 182 communicates with one end of the longitudinal groove 184 and the circumferential groove 12 and extends along the tread width direction. The lateral groove 186 communicates with the other end which is the end opposite to the one end of the longitudinal groove 184 and the circumferential groove 12 and extends along the tread width direction. The groove widths of the horizontal groove 182, the vertical groove 184, and the horizontal groove 186 are substantially the same and are narrower than the groove width of the circumferential groove 12. The groove depth from the ground surface G to the bottom surface 188 of the horizontal groove 182, the vertical groove 184, and the horizontal groove 186 is substantially the same, and is shallower than the circumferential groove depth from the ground surface G to the bottom surface of the circumferential groove 12.

(2.3) Comparison between the rib-like land portion 110 and the rib-like land portions 210 and 240 The first resonator (resonator R1, resonator R2) formed in the above-described rib-like land portion 110, and the rib-like land When compared with the second resonators (resonators R3 to R8) formed in the portion 210 (rib-shaped land portion 240), the volume of the first resonator is larger than the volume of the second resonator. Specifically, the total volume of the air chambers of the first resonators (resonators R1 and R2) located in the ground plane G that contacts the road surface RS is the second resonator located in the ground plane G. It is larger than the total volume of the air chambers of (resonators R3 to R8).

  Further, the number of second resonators (resonators R3 to R8) is larger than the number of first resonators (resonators R1 and R2). Specifically, the number of second resonators that is the sum of the resonators R3 to R8 is larger than the number of first resonators that is the sum of the number of resonators R1 and the number of resonators R2.

  Further, in a state where a normal load is applied to the pneumatic tire 10, the total volume of the resonators R1 and R2 located in the ground contact surface G that contacts the road surface RS is the total volume of the ground contact surface G. The total volume of the resonators of the resonators R3 to R8 located inside is greater than the total volume.

(3) Modification In the embodiment described above, the rib-shaped land portion 110 outside the vehicle is provided with the resonator R1 and the resonator R2 that are Helmholtz resonators. Similarly, the rib-like land portion 210 and the rib-like land portion 240 on the inner side of the vehicle are provided with resonators R3 to R8 that are side branch type resonators. In the modification, a rib-like land portion provided with a resonator that is a side branch type resonator will be described. Note that, in the following modifications, differences from the embodiment will be mainly described, and redundant description will be omitted.

(3.1) Modification 1
FIG. 5 is a partial front view of a tire according to a modification of the embodiment of the present invention. Specifically, FIG. 5 is a partial front view of the ground plane G according to a modification of the embodiment of the present invention. In the embodiment of the present invention, in the tread surface view, the longitudinal groove 184 of the resonator R5 extends along the tire circumferential direction, and the lateral groove 182 and the lateral groove 186 extend along the tread width direction. For example, as shown in FIG. 5 (a), the side branch type resonator includes a lateral groove 182A extending obliquely along the tread width direction and a tire circumferential direction. And a longitudinal groove 184A extending in part, and a part thereof may be curved. Further, the side branch type resonator may have the same shape along the tire circumferential direction.

  Further, as shown in FIG. 5B, a side branch type resonator may be formed by a lateral groove 182B extending obliquely along the tread width direction and a longitudinal groove 184B extending along the tire circumferential direction.

  Further, as shown in FIG. 5C, the side branch resonator may have a lateral groove 186C at a position other than the end of the longitudinal groove 184C extending along the tire circumferential direction.

(4) Comparative Evaluation Next, a test method for comparative evaluation between the pneumatic tire according to the example having the pattern similar to the pneumatic tire 10 described above and the pneumatic tire according to the comparative example and the result thereof will be described.

(4.1) Test method The noise level of the pneumatic tire according to the example and the comparative example was measured using a test vehicle. The test conditions for the comparative evaluation are as follows.

・ Test vehicle: Sedan type passenger car (Japanese car)
・ Used tire size: 215 / 55R17
・ Rim size used: 7J × 17
・ Set internal pressure: 210kPa
・ Set load: 4.41kN
・ Running speed: 80km / h
・ Measurement method: Noise is measured by installing a microphone in the car. (4.2) Test Results FIG. 6 shows the results of the tests related to the comparative evaluation described above. A comparative example is a pneumatic tire provided with no resonator. Example 1 is a pneumatic tire in which a pneumatic resonator 10 is provided with an outer first resonator on the entire tread when the vehicle is mounted. Example 2 is a pneumatic tire in which the pneumatic resonator 10 is provided with the second resonator on the entire tread when the vehicle is mounted. That is, Example 2 is a pneumatic tire in which the volume of the air chamber portion is smaller than that of Example 1 and the number of air chamber portions is set larger than that of Example 1.

  As shown in FIG. 6, the noise level is lowered by providing a resonator. In particular, in the pneumatic tire according to Example 1, the peak of outside noise having a volume level peak around 1 kHz can be significantly suppressed as compared with the comparative example. Further, in the pneumatic tire according to the second embodiment, it is possible to suppress the vehicle exterior noise having a wide frequency as a whole as compared with the comparative example. Further, it has been found that it is more effective for the noise felt by the human ear to suppress the vehicle exterior noise of a wide frequency as a whole like the pneumatic tire according to the second embodiment.

(5) Action / Effect According to the pneumatic tire 10 described above, the resonators R1 and R2 constituting the first resonator are located outside the resonators R3 to R8 constituting the second resonator when the vehicle is mounted. Therefore, it is possible to effectively reduce outside noise such as passing noise that is easily transmitted outward from a vehicle equipped with tires. The resonators R1 and R2 are Helmholtz resonators.

  Conventionally, the side branch type resonator has to change its volume according to the resonance frequency band. If the resonance frequency band is set to around 1 kHz, the volume of the side branch type resonator becomes large, and the rib-shaped land block is blocked. It is difficult to ensure rigidity. According to the pneumatic tire 10, since the resonator R1 and the resonator R2 constituting the first resonator are Helmholtz type resonators, the volume of the first resonator is made smaller than that of the side branch type resonator. Can do. Thereby, the resonator R1 and the resonator R2 can effectively reduce the outside noise with a smaller volume than the side branch type resonator.

  Further, since the resonator R1 and the resonator R2 can reduce the volume of the first resonator as compared with the side branch type resonator, the rib-like land portion 110 provided with the resonator R1 and the resonator R2 has a side branch type. The block rigidity can be ensured more than the rib-like land portion provided with the resonator.

  The volumes of the resonators R1 and R2 are larger than the volumes of the resonators R3 to R8. That is, since the resonator R1 and the resonator R2 are Helmholtz resonators having a large volume, it is possible to remarkably suppress the peak of outside noise having a volume level peak around 1 kHz.

  On the other hand, a plurality of resonators R3 to R8 are provided along the tire circumferential direction, and their volumes are smaller than the volumes of the resonators R1 and R2. For this reason, the block rigidity of the rib-shaped land part 210 (rib-shaped land part 240) falls moderately. As a result, road noise transmitted through the vehicle through the suspension, body, etc. can be reduced. In particular, road noise is likely to be transmitted from the inner part of the vehicle near the suspension and the tires close to the axle. Therefore, by providing resonators R3 to R8 having a small volume on the inner side of the vehicle, the road noise generated from the part is effective. Can be reduced.

  That is, according to such a tire, tire noise, particularly passing noise can be further reduced while ensuring the block rigidity of the rib-like land portion.

  Further, since the resonators R3 to R8 are side branch type resonators having the vertical groove 184, the horizontal groove 182 and the horizontal groove 186, the shape is simple and easy to manufacture. For this reason, the resonators R3 to R8 can be manufactured at a lower cost than the Helmholtz resonator.

  In general, when a negative camber is applied to the pneumatic tire 10, a wiping force for compressing the land portion by the contact pressure increases in the land portion on the inner side of the vehicle, and therefore, along the tread width direction. The formed lateral groove is easy to close. In the present embodiment, since the resonators R3 to R8, which are side branch type resonators, are provided in the rib-like land portion 210 (rib-like land portion 240), they are more than a Helmholtz resonator having a narrow groove portion with a narrow groove width. , Easy to secure the lateral groove, can reduce the road noise reliably.

  According to the present embodiment, the number of resonators R3 to R8 is larger than the number of resonators R1 and R2. Specifically, the total number of resonators R3 to R8 is larger than the total number of resonators R1 and R2. For this reason, the rib-like land portion 210 (rib-like land portion 240) where the resonators R3 to R8 are provided has more concave portions than the rib-like land portion 110 where the resonators R1 and R2 are provided. The As a result, the block rigidity of the rib-shaped land portion 210 (rib-shaped land portion 240) is further lowered than the block rigidity of the rib-shaped land portion 110, and road noise transmitted to the interior of the vehicle by transmitting the suspension, the body, and the like. Further reduction can be achieved.

  According to this embodiment, the length of the resonator R1 (resonator R2) along the tire circumferential direction is longer than the length of each of the resonators R3 to R8 along the tire circumferential direction. In addition, since the volumes of the resonators R1 and R2 are larger than the volumes of the resonators R3 to R8, the peak of outside noise can be further effectively reduced.

  According to this embodiment, the groove widths of the vertical groove 184, the horizontal groove 182, and the horizontal groove 186 are substantially the same. For this reason, the resonators R3 to R8 having the lateral groove 182, the longitudinal groove 184, and the lateral groove 186 function more effectively as a side branch type resonator. As a result, road noise transmitted through the vehicle by transmitting the suspension and the body can be further reduced. Further, the horizontal groove 182, the vertical groove 184, and the horizontal groove 186 are narrower than the groove width of the circumferential groove 12. For this reason, the block rigidity of the rib-shaped land part 210 (rib-shaped land part 240) falls more effectively.

  According to the present embodiment, since the groove depth from the ground plane G to the bottom surface 188 is substantially the same, the resonators R3 to R8 function more effectively as side branch type resonators. Further, the groove depth is shallower than the groove depth from the ground contact surface G to the bottom surface of the circumferential groove 12. For this reason, the block rigidity of the rib-shaped land part 210 (rib-shaped land part 240) falls more effectively.

  According to the present embodiment, the resonator R1 (resonator R2) is provided on the rib-like land portion 110 located on the outer side when the vehicle is mounted with the tire equator line CL as a reference, and thus is easily transmitted outward from the vehicle. Noise outside the vehicle such as passing noise can be reliably suppressed. Further, since the resonators R3 to R8 are provided on the rib-like land portion 210 (rib-like land portion 240) located on the inner side when the vehicle is mounted with respect to the tire equator line CL, the pneumatic tire 10 close to the suspension or the axle. It is possible to reliably suppress road noise that is easily transmitted from the inner part when the vehicle is mounted.

  According to the present embodiment, the number of resonators R3 to R8 positioned on the ground contact surface G is larger than the number of resonators R1 and R2 when a normal load is applied to the tire. Specifically, the total number of resonators R3 to R8 located on the ground plane G is larger than the total number of resonators R1 and R2. Therefore, the rib-like land portion 210 (rib-like land portion 240) where the resonators R3 to R8 are provided is formed with more concave portions than the rib-like land portion 110 where the resonator R1 (resonator R2) is provided. The As a result, the block rigidity of the rib-shaped land portion 210 (rib-shaped land portion 240) is lower than the block rigidity of the rib-shaped land portion 110, and road noise transmitted to the interior of the vehicle by transmitting the suspension and the body is further increased. It can be effectively suppressed.

(6) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, the shape of the Helmholtz resonator is not necessarily limited to the resonator R1 and the resonator R2 described above, and may be different shapes or shapes other than the resonator R1 and the resonator R2. .

  Further, the shape of the side branch type resonator is not necessarily limited to the above-described resonators R3 to R8, and may be different shapes or shapes other than the resonators R3 to R8.

  Further, in the above-described embodiment, the two resonators R1 and R2 are provided along the tire circumferential direction as the resonators that constitute the first resonator. It may be constituted only by the resonator R1, or may be constituted by three resonators. Similarly, as the resonators constituting the second resonator, six resonators R3 to R8 are provided along the tire circumferential direction. However, the present invention is not limited to this, and, for example, the resonator is configured only by the resonator R3. Also good.

  In the above-described embodiment, the circumferential grooves 11, 12, 21, and 22 extend linearly along the tire circumferential direction. However, if the circumferential groove extends along the tire circumferential direction, The shape is not limited to a straight line, and may be a zigzag shape or a wave shape.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

CL ... tire equator line, D1 ... direction, D2 ... direction, G ... ground contact surface, P ... spacing, Pc ... center portion, Ps ... shoulder portion, R1, R2, R3-R8 ... resonator, RS ... road surface, 10 ... Pneumatic tire, 11 ... circumferential groove, 11, 12, 21, 22 ... circumferential groove, 110, 210, 240 ... rib-like land portion, 120A, 120B, 140, 211, 241 ... land portion, 121 ... narrowed groove portion 121a, 121b ... end, 122 ... narrow groove, 130A, 130B ... air chamber part, 131 ... recessed portion, 132 ... bottom surface, 132a ... highest position, 132b ... lowest position, 182, 182A, 182B ... transverse groove, 184, 184A, 184B, 184C ... Vertical groove, 186, 186C ... Horizontal groove, 188 ... Bottom surface, 210,240 ... Rib-shaped land portion

Claims (7)

A plurality of rib-like land portions defined by a plurality of circumferential grooves extending along the tire circumferential direction;
A tire provided with a resonator that is recessed toward the inside in the tire radial direction, forming a predetermined space by the rib-shaped land portion contacting the road surface, and communicating with the circumferential groove,
The resonator is
A plurality of first resonators provided along the tire circumferential direction;
A plurality of second resonators that are located on the inner side of the first resonator than the first resonator and are provided along the tire circumferential direction,
The first resonator is a Helmholtz resonator having an air chamber portion recessed toward the inside in the tire radial direction, and a narrowed groove portion communicating with the air chamber portion and the circumferential groove,
The second resonator is a side branch type resonator having a longitudinal groove extending along a tire circumferential direction, and a lateral groove communicating with the longitudinal groove and the circumferential groove and extending along a tread width direction.
A tire in which the volume of the first resonator is larger than the volume of the second resonator.   The tire according to claim 1, wherein the number of the second resonators is larger than the number of the first resonators.  The tire according to claim 1 or 2, wherein a length of the first resonator along the tire circumferential direction is longer than a length of the second resonator along the tire circumferential direction.   The tire according to any one of claims 1 to 3, wherein a groove width of the vertical groove and the horizontal groove is substantially the same and is narrower than a groove width of the circumferential groove.   The groove depth from the ground contact surface where the rib-shaped land portion contacts the road surface to the bottom surface of the vertical groove and the horizontal groove is substantially the same, and the circumferential groove from the ground surface to the bottom surface of the circumferential groove The tire according to any one of claims 1 to 4, which is shallower than a depth. The first resonator is provided in a first rib-shaped land portion located on the outer side when the vehicle is mounted with reference to a tire equator line passing through the center in the tread width direction,
The tire according to any one of claims 1 to 5, wherein the second resonator is provided in a second rib-shaped land portion located on the inner side when the vehicle is mounted with respect to the tire equator line. .   7. The state according to claim 1, wherein in a state where a normal load is applied to the tire, the number of the second resonators located on the ground contact surface is greater than the number of the first resonators. tire.

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