JP2010167930A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of improving on-ice performance, on-snow performance and wet performance. <P>SOLUTION: In this pneumatic tire, the rotational direction is designated; main grooves 2 and 2 extending in the peripheral direction, an inclined groove 3 inclining outside in the width direction toward the opposite side of the rotational direction R and a crossing groove 4 inclining to the opposite side of the rotational direction R toward the outside in the width direction, are arranged in a tread part 1; a land part 10 extending in the peripheral direction is partitioned between the main grooves 2 and 2; a land part 20 is partitioned between the main groove 2 and the inclined groove 3; a land part 30 is partitioned outside in the width direction of the inclined groove 3; a plurality of sipes 12, 22 and 32 extending in the width direction are arranged in these land parts 10, 20 and 30; the inclined groove 3 is arranged so as to cross with the crossing groove 4; an inside end part 4b in the width direction of the crossing groove 4 is terminated in the land part 10 or the land part 20; the crossing groove 4 terminated in the land part 10 and the land part 20 is alternately arranged in the peripheral direction; an outside end part 3a in the width direction of the inclined groove 3 is terminated in the land part 30; and a groove width is gradually increased toward an inside end part 3b from the outside in the width direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire suitable as an icy and snowy road tire, and more particularly, to a pneumatic tire capable of improving performance on ice, performance on snow and wet performance.

  Conventionally, as an icy and snowy road tire, a plurality of main grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in the tire width direction are provided in the tread portion, and a plurality of tire grooves arranged in the tire circumferential direction by the main grooves and the lateral grooves. There has been proposed a pneumatic tire in which a plurality of land portions made up of blocks are partitioned and a plurality of sipes are provided in each block (for example, see Patent Document 1).

  In such a pneumatic tire, on-snow performance and wet performance are ensured based on the main groove and the lateral groove, and on-ice performance is secured by the edge effect of the sipe. However, when the groove area is increased in order to improve the performance on the snow and the wet performance, the performance on the ice is lowered due to the reduction of the contact area. Further, if the sipe is excessively increased to increase the edge effect, the block is likely to fall down, so that the performance on ice is not necessarily improved. Therefore, it is required for icy and snowy road tires to improve performance on ice, performance on snow and wet performance at a higher level.

Japanese Patent Laid-Open No. 10-24707

  An object of the present invention is to provide a pneumatic tire that can improve performance on ice, performance on snow, and wet performance.

  In order to achieve the above object, a pneumatic tire according to the present invention includes a pair of main grooves extending in the tire circumferential direction and positioned on both sides of the tire equator in the tread portion of the pneumatic tire having a designated rotation direction. A plurality of inclined grooves that are inclined outward in the tire width direction toward the opposite side of the rotation direction on both sides of the equator, and opposite to the rotation direction toward the outer side of the tire width direction on both sides of the tire equator. A plurality of transverse grooves inclined to the side, a first land portion extending continuously in the tire circumferential direction is defined between the pair of main grooves, and a plurality of grooves are provided between the main grooves and the inclined grooves. A second land portion made up of blocks, and a third land portion made up of a plurality of blocks on the outer side in the tire width direction of the inclined groove, and the first land portion, the second land portion, and the third land portion Multiple sipes extending in the tire width direction for each Each inclined groove is arranged so as to intersect with at least two transverse grooves, and the end of the transverse groove in the tire width direction is terminated in the first land portion or the second land portion, The transverse grooves terminating in the second land portion and the transverse grooves terminating in the second land portion are alternately arranged in the tire circumferential direction, and the end of the inclined groove on the outer side in the tire width direction is terminated in the third land portion. The groove width is gradually increased from the outer end in the tire width direction toward the inner end.

  In the present invention, the frictional force of adhesion is provided by disposing a plurality of sipes and a rib-shaped first land portion extending continuously in the tire circumferential direction in the center region of the tread portion around the tire equator. Can increase the performance on ice. Also, the inner end of the transverse groove in the tire width direction is terminated in the first land portion or the second land portion, and the transverse groove terminating in the first land portion and the transverse groove terminating in the second land portion are in the tire circumferential direction. By alternately arranging the blocks in the second land portion, the blocks in the second land portion are made larger than the blocks in the third land portion, but such a structure also contributes to an improvement in performance on ice.

  In addition, by arranging each inclined groove so as to intersect with at least two transverse grooves, and terminating the outer ends of the inclined grooves in the tire width direction within the third land portion, the length of the inclined grooves is sufficiently increased. Therefore, the edge effect on the lateral force when traveling on snow or traveling on a wet road surface can be increased, and the turning performance can be improved.

  Further, in addition to arranging a pair of main grooves on both sides of the tire equator, the groove width of the inclined grooves is gradually increased from the outer end in the tire width direction toward the inner end. It is possible to improve the wet performance by increasing the drainage capacity.

  In the present invention, it is preferable to provide a chamfered portion at the block acute angle portion sandwiched between the inclined groove and the transverse groove in the third land portion. Thereby, while improving drainage capacity and improving wet performance, the partial wear of a block acute angle part can be suppressed.

  A straight groove extending in the tire circumferential direction is preferably provided on the tire equator in the tread portion. Thereby, drainage capability can be improved and wet performance can be improved. This is particularly effective for large size tires.

  The sipe is preferably arranged in the first land portion, the second land portion, and the third land portion so as to extend along a grounded rear end line formed in an arc shape at the time of grounding. More specifically, it is preferable to gradually increase the inclination of the sipe extension direction with respect to the tire width direction in the order of the first land portion, the second land portion, and the third land portion. In the blocks of the second land part and the third land part defined by the inclined groove and the transverse groove described above, for example, when the sipe is arranged so as to extend in parallel to the tire width direction, the block collapse is suppressed. However, it is difficult to increase the number of sipes, but if the sipe is arranged so as to extend along the arc-shaped grounding end line, the number of sipes is increased as much as possible while suppressing the collapse of the block, and the performance on ice is improved. It becomes possible to improve the performance on snow.

  The tread pattern described above is effective as a pattern of a studless tire having no stud pins, but is also effective as a stud tire having stud pins. In the case of a stud tire, a plurality of stud pin driving positions are set in the second land part and the third land part, and sipes are arranged at positions deviating from the stud pin driving position in the second land part and the third land part. Is preferred. A stud pin is implanted in each stud pin driving position.

  In stud tires, it is preferable to disperse stud pin driving positions in the tire width direction in order to improve braking / driving force on snow and ice. Since the stud pin driving position cannot be set, the dispersion of the stud pin driving position in the tire width direction is limited. On the other hand, in the above tread pattern, although a pair of main grooves are arranged in the center region, a plurality of inclined grooves and a plurality of transverse grooves are arranged outside the center region, so that the stud pin driving position is Can be dispersed in the tire width direction. More specifically, at least seven rows of stud pin arrangement tracks are set on one side of the tire equator and outside the main groove in the tire width direction, and stud pin driving positions are dispersed on these stud pin arrangement tracks. It is preferable. Thereby, the braking / driving force on snow and ice can be improved.

It is an expanded view which shows the tread pattern of the pneumatic tire which consists of embodiment of this invention. FIG. 2 is a development view showing the tread pattern of FIG. 1 with a grounding shape added thereto. It is an expanded view which shows the tread pattern of the pneumatic tire which consists of other embodiment of this invention. It is an expanded view which shows the tread pattern of the pneumatic tire which consists of further another embodiment of this invention. FIG. 5 is a development view showing the tread pattern of FIG. 4 with a stud pin arrangement track added. It is an expanded view which shows an example of the tread pattern of the conventional pneumatic tire.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a tread pattern of a pneumatic tire according to an embodiment of the present invention. This pneumatic tire has a rotational direction R designated.

  As shown in FIG. 1, the tread portion 1 has a pair of main grooves 2 and 2 that are located on both sides of the tire equator E and extend in the tire circumferential direction, and opposite to the rotational direction R on both sides of the tire equator E. A plurality of inclined grooves 3 that incline toward the outer side in the tire width direction and a plurality of transverse grooves 4 that incline toward the opposite side of the rotational direction R toward the outer side in the tire width direction on both sides of the tire equator E, respectively. And are formed. Both the inclined groove 3 and the transverse groove 4 are repeatedly arranged at intervals in the tire circumferential direction. As a result, a land portion 10 (first land portion) extending continuously in the tire circumferential direction is defined between the pair of main grooves 2 and 2, and a plurality of blocks 21 are provided between the main groove 2 and the inclined grooves 3. A land portion 20 (second land portion) composed of a plurality of blocks 31 is defined outside the inclined groove 3 in the tire width direction.

  These land portions 10, 20, and 30 are provided with a plurality of sipes 12, 22, and 32 that extend in the tire width direction, respectively. Most of the sipes 12, 22, and 32 have a zigzag shape in plan view, but a part thereof is linear in plan view. The plan view shapes of these sipes 12, 22, and 32 are not particularly limited. Further, the sipes 12, 22, and 32 may have a three-dimensional structure having irregularities in the sipe thickness direction at a portion on the inner side in the tire radial direction from the tread surface.

  The inclined grooves 3 are slightly curved so as to protrude toward the tire equator E, and each inclined groove 3 is disposed so as to intersect with at least two transverse grooves 4. Here, “intersect” means a state in which two grooves penetrate each other. That is, in FIG. 1, each inclined groove 3 intersects with two transverse grooves 4. An end 3 a on the outer side in the tire width direction of the inclined groove 3 terminates in the land portion 30. Further, the groove width of the inclined groove 3 gradually increases from the outer end 3a in the tire width direction toward the inner end 3b.

  The transverse groove 4 is slightly curved so as to be convex toward the side opposite to the rotation direction R. These transverse grooves 4 have end portions 4 a on the outer side in the tire width direction extending to the outside of the ground contact end, but end portions 4 b on the inner side in the tire width direction terminate in the land portion 10 or the land portion 20. Further, the transverse grooves 4 are alternately arranged in the tire circumferential direction with those terminating in the land portion 10 and those terminating in the land portion 20. In the figure, the transverse grooves 4 that terminate in the land portion 10 and the transverse grooves 4 that terminate in the land portion 20 are arranged every other line, but the two transverse grooves 4 that terminate in the land portion 10 and the land One transverse groove 4 terminating in the land portion 20 is alternately arranged, or one transverse groove 4 terminating in the land portion 10 and two transverse grooves 4 terminating in the land portion 20 are alternately disposed. It is also possible to arrange them.

  In the pneumatic tire, a rib-like land portion 10 including a plurality of sipes 12 and continuously extending in the tire circumferential direction is disposed in the center region of the tread portion 1 centering on the tire equator E. Therefore, unlike the blocks arranged intermittently in the tire circumferential direction, even if a large number of sipes 12 are provided, the land portion 10 is unlikely to fall down. Therefore, the adhesion friction force can be increased and the performance on ice can be improved. In addition, since the transverse grooves 4 are terminated in the land portion 10 and are terminated in the land portion 20 alternately in the tire circumferential direction, the block 21 of the land portion 20 is replaced with the block 31 of the land portion 30. Bigger than. Thus, making the block 21 close to the tire equator E relatively large contributes to the improvement of performance on ice.

  Further, each inclined groove 3 is arranged so as to intersect with at least two transverse grooves 4, and an end 3 a on the outer side in the tire width direction of the inclined groove 3 is terminated in the land portion 30. A sufficient length can be secured. Thereby, the edge effect with respect to the lateral force when traveling on snow or traveling on a wet road surface can be increased, and the turning performance can be improved.

  Further, in addition to arranging the pair of main grooves 2 and 2 on both sides of the tire equator E, the groove width of the inclined groove 3 gradually increases from the outer end 3a to the inner end 3b in the tire width direction. By doing so, the drainage capacity in the center region can be enhanced and the wet performance can be improved. That is, in the pneumatic tire, a plurality of inclined grooves 3 are provided instead of the main grooves extending in the tire circumferential direction, and effective drainage is achieved by increasing the groove width of the inclined grooves 3 toward the tire equator side. It is possible.

  In the pneumatic tire, a chamfered portion 33 is formed at a block acute angle portion sandwiched between the inclined groove 3 and the transverse groove 4 in the land portion 30. The chamfered portion 33 is composed of a flat surface or a curved surface that is inclined from the tread surface toward the groove bottom. By providing the chamfered portion 33 at the block acute angle portion of the land portion 30 as described above, the drainage capacity is improved to improve the wet performance, and the uneven wear of the block acute angle portion having low rigidity can be suppressed.

  FIG. 2 shows the tread pattern shown in FIG. In FIG. 2, L is the outline of the grounding area formed in the normal use state. As shown in FIG. 2, in the land portions 10, 20, and 30, the sipe 12, 22, and 32 are grounded rear end lines that are formed in an arc shape at the time of grounding (portions opposite to the rotation direction R of the contour line L). It is arranged to extend along. More specifically, the inclination of the extending direction of the sipes 12, 22, and 32 with respect to the tire width direction gradually increases in the order of the land portions 10, 20, and 30. Here, the extending direction of the sipe means the direction of a straight line connecting the ends of each sipe. By arranging the sipes 12, 22 and 32 as described above, the number of sipes 22 and 32 can be increased as much as possible while suppressing the collapse of the blocks 21 and 31, and the performance on ice and the performance on snow can be improved. Become. In addition, when the sipes are arranged so as to extend in parallel to the tire width direction in the blocks 21 and 31 defined by the inclined grooves 3 and the transverse grooves 4, the sipes that can be arranged while avoiding the collapse of the blocks 21 and 31. The number of is extremely small. Further, when the sipe is arranged so as to extend along the transverse groove 4, the total length of the sipe that can be arranged while avoiding the collapse of the blocks 21 and 31 is extremely small.

  FIG. 3 shows a tread pattern of a pneumatic tire according to another embodiment of the present invention. In the present embodiment, a straight groove is added on the tire equator in the tread portion. Therefore, in FIG. 3, the same components as those in FIG.

  As shown in FIG. 3, a straight groove 5 continuous in the tire circumferential direction is formed on the tire equator E in the tread portion 1. The main groove 2 has a groove width of 5.0 mm to 15.0 mm and a groove depth of 5.0 mm to 12.0 mm, whereas the straight groove 5 has a groove width of 1.0 mm to 5.0 mm and a groove depth. Is 1.0 mm to 10.0 mm. By arranging the straight groove 5 on the tire equator E in this way, it is possible to enhance the drainage capacity and improve the wet performance in a particularly large tire. Further, the straight groove 5 contributes to improvement of the turning performance.

  FIG. 4 shows a tread pattern of a pneumatic tire according to still another embodiment of the present invention. This embodiment is a stud tire in which a number of stud pin driving positions are set in the tread portion. In FIG. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, a plurality of stud pin driving positions 6 are set on the land portions 20 and 30 located on the outer side in the tire width direction from the main groove 2. In these land portions 20 and 30, sipes 22 and 32 are arranged at positions away from the stud pin driving position 6. The stud pin driving position 6 may be formed with a planting hole when the tire is vulcanized, or may be opened with a drill after the tire is vulcanized. The stud pin is embedded by releasing the expansion of the implantation hole after inserting the stud pin into the implantation hole in a state where the implantation hole is expanded.

  According to the tread pattern, although the pair of main grooves 2 and 2 are arranged in the center region, a plurality of inclined grooves 3 and a plurality of transverse grooves 4 are arranged on the outside thereof, so that the stud pin The driving positions 6 can be dispersed in the tire width direction.

  FIG. 5 shows the tread pattern of FIG. 4 with a stud pin array track. As shown in FIG. 5, at least 7 rows, preferably 7-10 rows of stud pin arrangement tracks 7 are set in a region on one side of the tire equator E and outside the main groove 2 in the tire width direction. The center point of the stud pin driving position 6 may be dispersed on the stud pin arrangement track 7. Thereby, since the stud pin implanted in the stud pin driving position 6 dispersed in the tire width direction at the time of tire rotation scratches the snow surface and the ice surface, the braking / driving force on the snow and on the ice is improved. Can do.

  In a pneumatic tire of which the tire size is 205 / 55R16 and the rotation direction is specified, a pair of main grooves located on both sides of the tire equator and extending in the tire circumferential direction on the tread portion, and opposite to the rotation direction A plurality of inclined grooves inclined outward in the tire width direction toward the tire and a plurality of transverse grooves inclined outward in the tire width direction toward the opposite side of the rotational direction. A first land portion extending continuously in the direction is partitioned, a second land portion composed of a plurality of blocks is defined between the main groove and the inclined groove, and the plurality of blocks are formed outside the inclined groove in the tire width direction. And a plurality of sipes extending in the tire width direction in each of the first land portion, the second land portion, and the third land portion, and each of the inclined grooves as two transverse grooves. Arrange so that they cross each other Is terminated in the first land portion or in the second land portion, and the transverse groove terminating in the first land portion and the transverse groove terminating in the second land portion are alternately arranged in the tire circumferential direction, and the tire width direction of the inclined groove Tires of Examples 1 to 5 were produced in which the outer end portion was terminated in the third land portion, and the groove width of the inclined groove was gradually increased from the outer end portion in the tire width direction toward the inner end portion.

  In the tire of Example 1, as shown in FIG. 3, a chamfered portion is provided at a block acute angle portion sandwiched between the inclined groove and the transverse groove in the third land portion, and extends in the tire circumferential direction on the tire equator in the tread portion. A straight groove was provided, and the sipe was arranged so as to extend along the arc-shaped rear end line in the first land portion, the second land portion, and the third land portion.

  In the tire according to the second embodiment, a straight groove extending in the tire circumferential direction is provided on the tire equator in the tread portion, and sipes are formed along the arc-shaped grounding rear end line in the first land portion, the second land portion, and the third land portion. Arranged to extend. That is, in the second embodiment, unlike the first embodiment, the chamfered portion is not provided at the block acute angle portion sandwiched between the inclined groove and the transverse groove in the third land portion.

  In the tire of Example 3, a chamfered portion is provided in the block acute angle portion sandwiched between the inclined groove and the transverse groove in the third land portion, a straight groove extending in the tire circumferential direction is provided on the tire equator in the tread portion, The sipe was arranged to extend in parallel to the tire width direction in the land portion, the second land portion, and the third land portion.

  In the tire of Example 4, as shown in FIG. 1, a chamfered portion is provided in a block acute angle portion sandwiched between an inclined groove and a transverse groove in the third land portion, and the first land portion, the second land portion, and the third land portion are provided. In the land, the sipe was arranged so as to extend along the arc-shaped rear end line.

  In the tire of Example 5, as shown in FIG. 4, a chamfered portion is provided in the block acute angle portion sandwiched between the inclined groove and the transverse groove in the third land portion, and the first land portion, the second land portion, and the third land portion are provided. In the land portion, the sipe was arranged so as to extend along the arc-shaped rear end line, and a plurality of stud pin driving positions were set in the second land portion and the third land portion. Furthermore, stud pins were implanted at each stud pin driving position.

  For comparison, a conventional tire having a tread pattern shown in FIG. 6 was prepared for a pneumatic tire having the same tire size as above and designated in the rotational direction.

  For these tires, the following evaluation methods were used to evaluate snow braking performance, snow turning performance, snow feeling, ice braking performance, ice turning performance, wet braking performance, and wet turning performance. The results are shown in Table 1.

Snow braking performance:
The test tire was mounted on a vehicle with a displacement of 2500 cc class, braked from a running state of 40 km / h on snow at an air pressure of 230 kPa, and the braking distance was measured. The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. The larger the index value, the better the braking performance on snow.

Snow turning performance:
The test tire was mounted on a vehicle with a displacement of 2500 cc class, the air pressure was 230 kPa, a circular turn with a radius of 30 m was performed on the snow, and the average lap time was measured. The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. The larger the index value, the better the snow turning performance.

Snow feeling:
The test tire was mounted on a vehicle with a displacement of 2500 cc class and the air pressure was 230 kPa, and sensory evaluation was performed on the snow by a test driver. The evaluation results are shown as an index with the conventional example being 100. The larger the index value, the better the feeling on snow.

Ice braking performance:
The test tire was mounted on a vehicle with a displacement of 2500 cc class, braked from a running state of 40 km / h on ice at an air pressure of 230 kPa, and the braking distance was measured. The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. The larger the index value, the better the braking performance on ice.

Ice turning performance:
The test tire was mounted on a vehicle with a displacement of 2500 cc class, the air pressure was 230 kPa, a circular turn with a radius of 30 m was performed on ice, and the average lap time was measured. The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. The larger the index value, the better the turning performance on ice.

Wet braking performance:
The test tire was mounted on a vehicle with a displacement of 2500 cc class, braked from a running state at a speed of 80 km / h on a wet road surface with a water depth of 2.5 mm and an air pressure of 230 kPa, and the braking distance was measured. The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. A larger index value means better wet braking performance.

Wet turning performance:
The test tire was mounted on a vehicle with a displacement of 2500 cc class, the air pressure was 230 kPa, a circular turn with a radius of 30 m was performed on a wet road surface with a water depth of 2.5 mm, and the average lap time was measured. The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. The larger the index value, the better the wet turning performance.

  As is apparent from Table 1, the tires of Examples 1 to 5 are all on ice performance (ice braking performance, ice turning performance), snow performance (snow braking performance, snow turning performance, snow feeling) as compared to the conventional example. ), Wet performance (wet braking performance, wet turning performance) was excellent.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Main groove 3 Inclination groove 4 Transverse groove 5 Straight groove 6 Stud pin driving position 7 Stud pin arrangement track 10, 20, 30 Land part 12, 22, 32 Sipe 21, 31 Block 33 Chamfer E E Tire equator R Rotation direction

Claims (7)

  In a pneumatic tire with a specified rotation direction, a pair of main grooves located on both sides of the tire equator and extending in the tire circumferential direction are formed in the tread portion, and the rotation direction is opposite to the rotation direction on both sides of the tire equator. A plurality of inclined grooves inclined outward in the tire width direction and a plurality of transverse grooves inclined outward in the tire width direction on both sides of the tire equator, respectively. A first land portion extending continuously in the tire circumferential direction between the main grooves, and a second land portion composed of a plurality of blocks between the main groove and the inclined groove, and the inclined groove Partitioning the third land portion composed of a plurality of blocks on the outer side in the tire width direction, and providing a plurality of sipes extending in the tire width direction in each of the first land portion, the second land portion and the third land portion, Cross each inclined groove with at least two transverse grooves The transverse groove that ends in the tire width direction of the transverse groove is terminated in the first land portion or the second land portion, and the transverse groove that terminates in the first land portion and the transverse groove that terminates in the second land portion. Are alternately arranged in the tire circumferential direction, the end of the inclined groove on the outer side in the tire width direction is terminated in the third land portion, and the groove width of the inclined groove on the inner end from the outer end in the tire width direction Pneumatic tire characterized by gradually increasing toward the vehicle.   The pneumatic tire according to claim 1, wherein a chamfered portion is provided at a block acute angle portion sandwiched between the inclined groove and the transverse groove in the third land portion.   The pneumatic tire according to claim 1, wherein a straight groove extending in a tire circumferential direction is provided on the tire equator in the tread portion.   The sipe is disposed in the first land portion, the second land portion, and the third land portion so as to extend along a grounded rear end line formed in an arc shape at the time of grounding. The pneumatic tire according to any one of the above.   The pneumatic tire according to claim 4, wherein the inclination of the sipe extending direction with respect to the tire width direction is gradually increased in the order of the first land portion, the second land portion, and the third land portion.   A plurality of stud pin driving positions are set in the second land part and the third land part, and the sipe is disposed at a position deviating from the stud pin driving position in the second land part and the third land part. The pneumatic tire according to any one of claims 1 to 5.   At least seven rows of stud pin arrangement tracks are set on one side of the tire equator and outside the main groove in the tire width direction, and the stud pin driving positions are dispersed on the stud pin arrangement tracks. The pneumatic tire according to claim 6.

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