JP2012006509A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of reducing noise generated when a land section between resonators, arranged between adjoining resonator grooves hits a road surface, in a case where the plurality of resonator grooves are provided along a tire circumference direction with prescribed intervals.SOLUTION: A tread part which touches road surface, includes the plurality of resonator grooves 5 and 6 arranged along the tire circumference direction with prescribed intervals. Hardness of a rubber which constitutes a land section between resonators 5 and 6, which is provided between a first resonator groove 5 and a second resonator groove 6 adjoining to the first resonator groove 5 in the tire circumference direction is made lower than that of a rubber for constituting a land section of other parts.

Description

  The present invention relates to a pneumatic tire.

  Conventionally, it has been desired to reduce noise generated by a tire coming into contact with a road surface while the vehicle is running. In order to reduce this noise, a resonator groove may be formed in the tread portion in contact with the road surface.

  For example, the tire described in Patent Document 1 is provided with a resonator groove formed by an air chamber portion and a constricted neck at a predetermined interval along the tire circumferential direction, thereby reducing noise caused by the circumferential groove. Reduced. Furthermore, by providing another lateral groove in a predetermined rib-shaped land portion between the resonator grooves, a rib-shaped land along the tire circumferential direction generated by disposing a plurality of resonator grooves intermittently. The difference in rigidity of the part is reduced, and the pitch noise caused by the resonator groove is also reduced. (For example, refer to Patent Document 1).

JP 2008-207610 A

  By the way, the tire described above has the following problems. That is, because the resonator groove and the lateral groove and the land portion are alternately repeated along the tire circumferential direction, when the tire rolls, the vibration caused by the tread portion hitting the road surface, and the vibration There is a possibility that the noise to be reduced cannot be reduced.

  Therefore, the present invention provides vibration generated when a land portion located between adjacent resonator grooves hits a road surface when a plurality of resonator grooves are provided at predetermined intervals along the tire circumferential direction. And it aims at providing the pneumatic tire which can reduce the noise resulting from the vibration.

  A first feature of the present invention is a pneumatic tire having a plurality of resonator grooves provided at predetermined intervals along a tire circumferential direction in a tread portion in contact with a road surface. Resonance provided between the first resonator groove (first resonator groove 5) and the second resonator groove (second resonator groove 6) adjacent to the first resonator groove in the tire circumferential direction. The hardness of the rubber composing the inter-groove land (resonator inter-groove land 9) is lower than the hardness of the rubber composing other land parts (inner land part 3, outer land part 4). Is the gist.

  According to this, the hardness of the rubber constituting the land portion between the resonator grooves disposed between the first resonator groove and the second resonator groove is determined from the hardness of the rubber constituting the land portion of the other part. Lowering the rigidity to reduce the rigidity can suppress the difference in rigidity along the tire circumferential direction of the tread portion. Therefore, the uniformity is improved, and the in-vehicle noise can be reduced when the vehicle is traveling.

  A second feature of the present invention relates to the first feature, wherein the resonator groove (first resonator groove 5, second resonator groove 6) includes a lateral groove portion (lateral groove portion 7) extending in the tread width direction, and It is integrally formed with a longitudinal groove portion (vertical groove portion 8) that communicates with the transverse groove portion and extends in the tire circumferential direction, and the inter-resonator groove land portion (resonator groove land portion 9) is provided between the longitudinal groove portions. It is a summary.

  A third feature of the present invention relates to the first or second feature, wherein the hardness of the rubber constituting the resonator inter-groove land portion is 80 to 90 with respect to the hardness of the rubber constituting the land portion of another portion. %.

  A fourth feature of the present invention relates to any one of the first to third features, wherein the inter-resonator groove land portion (resonator groove land portion 9) is separated from the land portion of other parts. The gist is that it is composed.

  According to the pneumatic tire according to the present invention, the uniformity is improved, and it is possible to reduce the in-vehicle sound when the vehicle is running.

FIG. 1 is a partially enlarged view showing a tread pattern of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is an enlarged view showing a main part of the tread pattern of FIG. FIG. 3 is an enlarged cross-sectional view taken along line AA in FIG. 4 is an enlarged cross-sectional view taken along line BB in FIG.

  Hereinafter, details of a pneumatic tire according to an embodiment of the present invention will be described with reference to the drawings. Specifically, (1) Schematic configuration of tread pattern, (2) Detailed structure of resonator groove and inter-resonator groove land, (3) Examples, (4) Operational effects, (5) Other embodiments Will be described. 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.

(1) Overall Configuration of Tread Pattern FIG. 1 is a partially enlarged view showing a tread pattern of a pneumatic tire according to an embodiment of the present invention.

  As shown in FIG. 1, a tread surface in contact with the road surface is formed with a central circumferential groove 1 extending in the tire circumferential direction on the center side in the tread width direction, and outside the tread width direction 1 from the central circumferential groove 1. The end side circumferential groove 2 is formed on the end side. In the present embodiment, the center-side circumferential groove 1 is formed on the tire equator line CL. However, the present invention is not limited to this, and the center-side circumferential groove 1 may not be on the tire equator line CL. Good.

  Further, an inner land portion 3 and an outer land portion 4 are formed between the center side circumferential groove 1 and the end side circumferential groove 2, and the outer land portion 4 has a predetermined interval in the tire circumferential direction. A plurality of resonator grooves are intermittently disposed. FIG. 1 shows a predetermined first resonator groove 5 and a second resonator groove 6 adjacent to the first resonator groove 5 in the tire circumferential direction among the plurality of resonator grooves.

(2) Detailed structure of the resonator groove and the land portion between the resonator grooves FIG. 2 is an enlarged view showing a main part of the tread pattern of FIG.

  The first resonator groove 5 will be described as an example. The first resonator groove 5 is formed of a lateral groove portion 7 extending in the tread width direction and a longitudinal groove portion 8 communicating with the lateral groove portion 7 and extending in the tire circumferential direction. In the tread surface view, it has an inverted L shape.

  The lateral groove portion 7 has one end 7a communicating with the end-side circumferential groove 2 and the other end 7b communicating with the longitudinal groove portion 8, and is formed with an inclination angle of about 45 ° with respect to the tread width direction. The longitudinal groove 8 has one end 8 a connected to the other end 7 b of the lateral groove 7 and the other end 8 b terminating in the outer land portion 4. The width of the vertical groove portion 8 is formed substantially the same as the width of the center side circumferential groove 1 and the end side circumferential groove 2 shown in FIG.

  In addition, an inter-resonator groove land portion 9 is provided between the longitudinal groove portion 8 of the first resonator groove 5 and the longitudinal groove portion 8 of the second resonator groove 6 along the tire circumferential direction.

  Here, FIG. 3 which is an enlarged sectional view taken along line AA in FIG. 1 and FIG. 4 which is an enlarged sectional view taken along line BB in FIG. .

  As shown in FIG. 3, in the 1st resonator groove | channel 5, the vertical groove part 8 acts as an air chamber part. The vertical groove portion 8 is formed in a rectangular cross section from the bottom surface 10 and the side surface 11, and the width in the tread width direction is set to W0 and the depth in the tire radial direction is set to H0. On the other hand, as shown in FIG. 4, the inter-resonator groove land portion 9 is configured separately from the inner land portion 3 and the outer land portion 4, and the width in the tread width direction is W1 (see FIG. 2). The width in the tire circumferential direction is W2, and the height in the tire radial direction is H1.

  In this embodiment, the width W1 of the inter-resonator groove land portion 9 is set to be the same as the width dimension W0 of the longitudinal groove portion 8 described above, and the width W1 of the inter-resonator groove land portion 9 is equal to the resonator groove. It is set to be the same as the width W2 of the inland portion 9. The height H1 of the inter-resonator groove land 9 is set to be the same as the depth H0 of the longitudinal groove 8. Thus, the resonator inter-groove land portion 9 is formed in a rectangular parallelepiped shape. Moreover, although the land part 9 between resonator grooves is formed with rubber like the other land parts 3 and 4, the hardness of the rubber which comprises the land part 9 between resonator grooves is other land parts 3,3. 4 is set lower than the hardness of the rubber constituting 4. Specifically, the hardness of the rubber that forms the inter-resonator groove land portion 9 is 80 to 90% of the hardness of the rubber that forms the land portions 3 and 4. That is, the rubber constituting the inter-resonator groove land portion 9 is separate from the rubber constituting the land portions 3 and 4, and is formed of a member different from the rubber constituting the land portions 3 and 4. In the present embodiment, the inter-resonator groove land portion 9 is provided so as to partition the longitudinal groove portion 8 in the tire circumferential direction, and is fixed via an adhesive (not shown).

  Here, the air column resonance sound is a noise generated by resonance generated in a pipe formed by a groove formed on a tread portion of the tire and a road surface when the tire rolls. The frequency is often observed at about 800 to 1200 Hz in a general passenger car, and is one of the main noises directly attributed to tires due to the peak height and bandwidth.

(3) Examples Next, the present invention will be described more specifically through examples.

  In this example, a pneumatic tire having a tire size of 255/40 ZR19 was used. In the tread portion, a plurality of resonator grooves similar to those of the above-described embodiment are arranged along the tire circumferential direction, and the resonance formed separately from other land portions between these resonator grooves. The rubber in the inter-groove land was arranged. About the magnitude | size of the rubber | gum of a resonator groove | channel land part, it forms in the same dimension as the boundary groove part between the longitudinal groove parts of mutually adjacent resonator grooves. Specifically, the circumferential length of the rubber is the same as the circumferential length of the boundary groove, the width of the rubber is the same as the width of the boundary groove, and the height of the rubber is the same as the depth of the boundary groove. is there.

  Four types of pneumatic tires with appropriate changes in the number of the resonator grooves and the hardness of the rubber constituting the other land portions were prepared, and the noise in the passenger compartment when the vehicle was run while being assembled to each vehicle was compared. . Table 1 shows the configuration of each pneumatic tire and the noise evaluation results.

The evaluation of noise was a feeling evaluation in the test course by an evaluation driver, with 4 points for good, 3 points for tolerance, 2 points for lack, and 1 point for bad.

  From the results of Table 1, the results of evaluation of the in-vehicle sound in Examples 1 and 2 were better than those in Conventional Examples 1 and 2, and the effect of the present invention was demonstrated.

(4) Effects Next, functions and effects of the pneumatic tire according to the present embodiment will be described.

  The pneumatic tire according to the present embodiment has a plurality of resonator grooves arranged at predetermined intervals along the tire circumferential direction in the land portions 3 and 4 of the tread portion, and the first resonator groove 5 of these The hardness of the rubber constituting the inter-resonator groove land portion 9 disposed between the first resonator groove 5 and the second resonator groove 6 adjacent in the tire circumferential direction is set to the land portions 3 and 4 of other portions. It is lower than the hardness of the rubber that composes.

  According to this, the hardness of the rubber constituting the inter-resonator groove land portion 9 disposed between the first resonator groove 5 and the second resonator groove 6 is set to the land portions 3 and 4 of other portions. By reducing the rigidity by making it lower than the hardness of the constituent rubber, it is possible to suppress the rigidity difference along the tire circumferential direction in the tread portion in contact with the road surface. Therefore, the uniformity is improved, and the in-vehicle noise can be reduced when the vehicle is traveling. In general, the in-vehicle sound due to resonance with vehicle characteristics is mainly generated at a frequency in the vicinity of 200 to 250 Hz at a traveling speed of 80 to 160 km / hour. Therefore, the number of resonator grooves that can be in the vicinity of 200 to 250 Hz ( For example, when the present invention is applied at the time of 20 or less), a higher vehicle interior sound reduction effect can be obtained.

  In the pneumatic tire according to the present embodiment, the resonator grooves 5 and 6 are integrally formed from the lateral groove portion 7 extending in the tread width direction and the vertical groove portion 8 communicating with the lateral groove portion 7 and extending in the tire circumferential direction. The inter-resonator groove land portion 9 is disposed between the longitudinal groove portions 8 and 8. Here, when considering the entire tread portion, the land portions disposed between the longitudinal groove portions 8 of the adjacent resonator grooves 5 and 6 easily hit the road surface at the time of tire rolling, and noise is likely to be generated. By arranging the resonator inter-groove land portion 9 having a low hardness at the land portion, the in-vehicle sound during traveling can be efficiently reduced.

  Further, in the pneumatic tire according to the present embodiment, the hardness of the rubber constituting the resonator inter-groove land portion 9 is 80 to 90% of the hardness of the rubber constituting the land portions 3 and 4 of other portions. When the hardness of the rubber constituting the resonator inter-groove land portion 9 is larger than 90% of the hardness of the rubber constituting the land portions 3 and 4 of other parts, the rubber constituting the resonator inter-groove land portion 9 and Since the difference in rigidity with the rubber constituting the land portions 3 and 4 of other parts is reduced, it is difficult to reduce the vehicle interior noise during traveling. On the other hand, when the hardness of the rubber constituting the resonator inter-groove land portion 9 is smaller than 80% of the hardness of the rubber constituting the land portions 3 and 4 of other parts, the durability of the pneumatic tire during traveling of the vehicle It is difficult to ensure.

  Moreover, according to the pneumatic tire according to the present embodiment, the resonator inter-groove land portion 9 is formed separately from the land portions 3 and 4 of other portions, and therefore the land portion 3 of other portions. , 4 can be easily adjusted.

(5) Other Embodiments It should not be understood that the description and drawings that constitute 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.

  For example, in the embodiment, the width dimension W1 and the height H1 of the inter-resonator groove land portion 9 are the same as the width dimension W0 and the depth H0 of the longitudinal groove portion 8 of the first resonator groove 5. However, the present invention is not limited to this, and the width dimension W1 of the inter-resonator groove land portion 9 is set to 50% to 100% with respect to the width dimension W0 of the longitudinal groove portion 8, and the height of the inter-resonator groove land portion 9 is increased. The height H1 may be 50% to 100% with respect to the depth H0 in the vertical groove portion 8.

  Moreover, in this embodiment, although the resonator interstitial land part 9 was comprised separately from the other land parts 3 and 4, this invention is not limited to this, It is lower than the other land parts 3 and 4 You may form in the state made into hardness, and the other land parts 3 and 4 integrally.

DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire, 3 ... Inner land part (other land part), 4 ... Outer land part (other land part), 5 ... 1st resonator groove (resonator groove), 6 ... 2nd resonator groove (Resonator groove), 7 ... transverse groove portion, 8 ... vertical groove portion, 9 ... land portion between resonator grooves

Claims (4)

In the tread part in contact with the road surface,
A pneumatic tire having a plurality of resonator grooves provided at predetermined intervals along the tire circumferential direction,
The rubber constituting the inter-resonator groove land portion provided between the first resonator groove of the resonator grooves and the second resonator groove adjacent to the tire resonator in the tire circumferential direction. A pneumatic tire characterized in that the hardness is lower than the hardness of rubber constituting the land portion of other parts. The resonator groove is integrally formed from a horizontal groove portion extending in the tread width direction and a vertical groove portion communicating with the horizontal groove portion and extending in the tire circumferential direction,
The pneumatic tire according to claim 1, wherein the resonator inter-groove land portion is disposed between the longitudinal groove portions. The hardness of the rubber constituting the resonator inter-groove land portion is:
3. The pneumatic tire according to claim 1, wherein the pneumatic tire has a hardness of 80 to 90% with respect to a hardness of rubber constituting a land portion of another portion.   The pneumatic tire according to any one of claims 1 to 3, wherein the resonator inter-groove land portion is configured separately from land portions of other portions.

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