JP2009018619A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire that can improve both the braking performance of a tread on iced-and-snowed road and wear resistance and uneven wear resistance. <P>SOLUTION: A plurality of block rows 3, which are formed by a plurality of main grooves 2 extending in the tire circumferential direction, are provided on the surface of a tread 1. Among many blocks 5 where the block rows 3 are divided by lug grooves 4, first sipe rows 6, which are arranged both ends of the tire circumferential direction and extended in the tire widthwise direction, and second sipe rows 7, 8, which are arranged in the middle part of the tire circumferential direction and extended in the tire widthwise direction, are provided on the block 5A on the tire equatorial surface CL. The first sipe rows 6 are cut at the center part of the tire widthwise direction and both ends thereof are terminated inside the block 5A, while the second sipe rows 7, 8 are cut at the center part of the tire widthwise direction and at least one ends thereof are communicated with the main grooves 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pneumatic tire having a plurality of blocks in a tread, and more particularly to a pneumatic tire suitable for use as a winter statless tire.

  For example, in a statless tire that can be used on ice and snow in winter, the contact pressure at the center in the width direction of the tread is increased by means such as reducing the radius of curvature in the width direction of the tread, and the braking performance on ice and snow is fully demonstrated. It is supposed to let you. However, when the contact pressure at the center part in the width direction of the tread is increased as described above, the heel and toe uneven wear in which the kicking side of the block at the center part in the width direction of the tread is worn significantly, or the center part in the width direction of the tread However, there is a problem that center wear that wears faster than the shoulder portion as a whole tends to occur. In particular, in light truck tires, the tire input is stricter than that of passenger cars and the tire size is smaller than that of ordinary trucks. Difficult to balance with uneven wear performance. On the other hand, when used as a statless tire, it is extremely important to ensure the braking performance of the tread on ice and snow for safety.

  Therefore, as disclosed in Patent Document 1, a plurality of blocks are provided on the surface of the tread, and the sipe that extends in the tire width direction and ends in each block at both ends in the tire circumferential direction of each block. The so-called closed sipes are arranged, and between these closed sipes, a sipe extending in the tire width direction and having one end terminating in each block and the other end communicating with the main groove, so-called closed sipes on one side, is placed in the air. Tires have been proposed. In this pneumatic tire, the rigidity of the block is increased by closed sipes arranged at both ends of the tire in the circumferential direction of the block, so it is possible to improve the uneven wear resistance performance of the tread, and the sipe with one closed sipe disposed between the closed sipes. By securing the length, braking performance on snowy and ice roads due to the edge effect can be improved.

  On the other hand, in Patent Document 2, a block on the tread surface is provided with a sipe row extending in a zigzag shape in the tire width direction and divided at a central portion in the tire width direction, and a tire circumferential direction is formed in a part of the sipe row. There is disclosed a pneumatic tire in which a pseudo circumferential sipe extending in the direction of the tire is formed. This pneumatic tire can improve braking performance on ice by incorporating a water film at the center of the block with a quasi-circumferential sipe that extends in the tire circumferential direction when running on ice, and the sipe train is divided at the center in the tire width direction. By doing so, the rigidity of the block is increased, so that the wear resistance can be improved.

Furthermore, Patent Document 3 discloses a pneumatic tire in which a sipe extending in a zigzag shape in the tire width direction and having an amplitude in the depth direction is arranged on a block on the tread surface. In this pneumatic tire, by forming a sipe having a zigzag shape extending in the tire width direction and having an amplitude in the depth direction on the block, uneven wear on the kicking side of the block can be suppressed, and the tread surface has wrinkles and the like. The generated bear defect can be reduced.
JP-A-6-219108 Japanese Patent Laid-Open No. 2003-211920 JP 2005-153787 A

  However, in the pneumatic tire described in Patent Document 1 described above, the rigidity of the block is increased by closed sipes disposed at both ends of the block in the tire circumferential direction, and uneven wear resistance performance at both ends of the block can be improved. However, the center wear in which the center portion in the width direction of the tread was worn faster than the shoulder portion could not be suppressed. On the other hand, in the pneumatic tire described in Patent Document 2 described above, although wear at the center in the tire width direction of the block can be suppressed, there is a problem that uneven wear at both ends in the tire circumferential direction of the block is likely to occur. .

  Moreover, in the pneumatic tire described in Patent Document 3 described above, uneven wear on the kicking side of the block can be suppressed, but center wear in which the center portion in the width direction of the tread wears faster than the shoulder portion cannot be suppressed. .

  Therefore, the present invention has been made to solve the above-described problems, and provides a pneumatic tire that can improve both the braking performance, wear resistance performance, and uneven wear resistance performance of a tread on ice and snow. The purpose is to do.

  In the invention of claim 1, a plurality of block rows are formed on the surface of the tread by a plurality of main grooves extending in the tire circumferential direction, and the block rows are partitioned into a plurality of blocks by lug grooves extending in the tire width direction. In the pneumatic tire that is, in a predetermined block formed in any of the block row, a first sipe row that is disposed at both ends in the tire circumferential direction of the block and extends in the tire width direction, A second sipe row disposed in the tire circumferential direction of the block and extending in the tire width direction is provided, and the first sipe row is divided at a central portion of the block in the tire width direction. And both ends terminate in the block, the second sipe row is divided at a central portion of the block in the tire width direction, and at least one end communicates with the main groove. And wherein the door.

  The invention according to claim 2 is the invention according to claim 1, wherein the block row in which the first sipe row and the second sipe row are formed is closest to the block row on the tire equator plane or the tire equator plane. A block sequence is included.

  The invention according to claim 3 is the invention according to claim 1 or 2, characterized in that the first sipe rows arranged at both ends of the block in the tire circumferential direction are sipe having an amplitude in the depth direction. And

  The invention according to claim 4 is the invention according to claim 3, characterized in that the second sipe row arranged in the intermediate portion of the block in the tire circumferential direction is formed of a sipe that is straight in the depth direction. .

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, a position where the first sipe row and the second sipe row are divided at a central portion in the tire width direction is adjacent. The sipe trains differ in the tire width direction.

  According to the first aspect of the present invention, the first sipe rows arranged at both ends in the tire circumferential direction that are most easily deformed in the block on the tread surface are terminated at both ends in the block and divided at the center in the tire width direction. Therefore, the rigidity of both ends of the tire in the tire circumferential direction is increased, and the sipe can be prevented from greatly opening when kicking out while rolling the tire, so that the uneven wear resistance performance of the block can be improved. it can. Furthermore, since the second sipe row is divided at the central portion in the tire width direction of the block, the rigidity of the central portion in the tire width direction of the block is also increased, and the sipe can be prevented from greatly opening during tire rolling. The wear resistance performance of the entire block can be improved. Further, since at least one end of the second sipe row communicates with the main groove to ensure the sipe length, the braking performance on the snowy and ice road due to the edge effect can be improved. That is, as described above, by providing a combination of a plurality of sipe rows having different roles at predetermined locations on the block of the tread surface, both the braking performance, wear resistance performance, and uneven wear resistance performance of the tread on ice and snow are provided. Can be improved.

  According to the invention of claim 2, since the first sipe row and the second sipe row are formed in the block row on the tire equator plane or the block row closest to the tire equator plane, the width direction of the tread When the ground contact pressure at the center is increased, the effects of the first sipe row and the second sipe row are particularly effective, that is, the tread braking performance, wear resistance performance and uneven wear resistance performance on ice and snow. Both can be improved.

  According to the invention of claim 3, since the first sipe rows arranged at both ends of the tire in the tire circumferential direction are sipe having an amplitude in the depth direction, the straight line without having an amplitude in the depth direction. Compared to the sipe, the sipe is strong against the falling of the block and is difficult to close. Also in this respect, the rigidity of the block is high, so that the uneven wear resistance can be improved.

  According to the invention of claim 4, since the second sipe row arranged in the intermediate portion of the block in the tire circumferential direction is made of a sipe that is straight in the depth direction (constant depth), this point is also effective on ice and snow. The tread braking performance can be improved.

  According to the invention of claim 5, since the position where the first sipe row and the second sipe row are divided at the center in the tire width direction is different in the tire width direction between adjacent sipe rows, the tire width The rigidity of the block can be increased over a relatively wide range of directions.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of the present invention, FIG. 1 is a developed view of a tread of a pneumatic tire, FIG. 2 is an enlarged view showing a block of a tread surface, and FIG. 3 is an XX of FIG. It is a perspective view of a section along a line.

  In the pneumatic tire of the present embodiment, a plurality of block rows 3 are formed on the surface of the tread 1 by a plurality of main grooves 2 extending in the tire circumferential direction, and the block rows 3 are formed by lug grooves 4 extending in the tire width direction. It is partitioned into a large number of blocks 5. These blocks 5 include blocks 5A formed by partitioning a block row 3A on the tire equatorial plane CL.

  The blocks 5A on the tire equatorial plane CL are arranged at both ends of the block 5A in the tire circumferential direction, and extend in a zigzag manner in the tire width direction, and in the middle of the block 5A in the tire circumferential direction. There are provided second sipe rows 7 and 8 that are arranged and extend in a zigzag shape in the tire width direction. The second sipe row 7 is arranged at the center position in the tire circumferential direction of the block 5A, and the second sipe row 8 is arranged on each side of the second sipe row 7 in the tire circumferential direction.

  The first sipe row 6 is divided at the center in the tire width direction of the block 5A, and has an amplitude in the depth direction on both sides of the divided portion 6c in the tire width direction, and the tips are respectively in the block 5A. A pair of sipes 6a and 6b are formed. The second sipe row 7 is divided at the center in the tire width direction of the block 5A, and is straight on both sides of the divided portion 7c in the tire width direction without amplitude in the depth direction. Is formed with a pair of sipes 7a and 7b communicating with the main groove 2, respectively. The other second sipe row 8 is divided at the center portion in the tire width direction of the block 5A, and has an amplitude in the depth direction on both sides of the divided portion 8c in the tire width direction. A pair of sipes 8a and 8b communicating with the main groove 2 are formed.

  As for the amplitude in the depth direction of the first sipe row 6 and the second sipe row 8, as shown in FIG. 3, a sipe is linearly formed along the depth direction at a predetermined depth from the tread surface. In a deeper portion, sipes are formed in a zigzag shape with a predetermined amplitude.

  The positions of the dividing portions 6c, 7c, and 8c that divide the sipe rows 6 to 8 at the center in the tire width direction are different in the tire width direction between adjacent sipe rows. Each sipe 6a, 6b of the first sipe row 6 is formed in a zigzag shape by alternately connecting short pieces 6d inclined in opposite directions, and the other sipes 7a, 7b, 8a, 8b are also formed. Each is the same.

  In the embodiment configured as described above, both ends of the first sipe row 6 disposed at both ends in the tire circumferential direction that are most easily deformed in the block 5A on the surface of the tread 1 terminate in the block 5A and the center in the tire width direction. Therefore, the rigidity of both ends in the tire circumferential direction of the block 5A is increased, and the sipes 6a and 6b can be prevented from being greatly opened when kicking out while the tire is rolling. The uneven wear resistance can be improved. Further, since the sipes 6a and 6b of the first sipe row 6 have an amplitude in the depth direction, the block 5A falls down (sipes 6a and 6b) as compared with a case where the sipe 6a and 6b has no amplitude in the depth direction and is straight. In this respect, the rigidity of the block 5A is increased, so that the uneven wear resistance of the block 5A can be improved. Furthermore, since the second sipe rows 7 and 8 are divided by the dividing portions 7c and 8c in the center of the tire width direction of the block 5A, the rigidity of the central portion of the block 5A in the tire width direction is also increased, and the tire is rolling. Since the sipes 7a, 7b, 8a, and 8b can be prevented from greatly opening, the wear resistance performance of the entire block 5A can be improved. That is, as described above, by providing a combination of a plurality of sipe rows 6 to 8 having different roles at a predetermined position of the block 5A on the surface of the tread 1, the braking performance, wear resistance, and anti-resistance of the tread 1 on ice and snow are provided. Both the uneven wear performance can be improved.

  Further, according to this embodiment, at least one end of each of the second sipe rows 7 and 8 communicates with the main groove 2 to secure the sipe length, so that it is possible to improve the braking performance on the snow and ice road due to the edge effect. . Furthermore, since the sipes 8a and 8b of the second second sipe row 8 have amplitude in the depth direction, the sipes 8a and 8b are closed as compared with the case where the sipes 8a and 8b have no amplitude in the depth direction and are straight. It is difficult to improve braking performance especially on ice.

  Further, according to this embodiment, the first sipe row 6 and the second sipe rows 7 and 8 are formed in the block 5A of the block row 3A on the tire equatorial plane CL, so that the center of the tread 1 in the width direction is formed. The effect of the first sipe row 6 and the second sipe row 7 and 8 is particularly effective when the contact pressure of the section is increased, that is, the braking performance and wear resistance performance of the tread 1 on ice and snow, and Both uneven wear resistance and performance can be improved.

  Further, according to this embodiment, the position at which the first sipe row 6 and the second sipe row 7, 8 are divided at the center portion in the tire width direction differs in the tire width direction between adjacent sipe rows. Therefore, the rigidity of the block 5A can be increased over a relatively wide range in the tire width direction.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modifications can be made.

  For example, in the above-described embodiment, the case where the sipe rows 6 to 8 are arranged in the block 5A on the tire equatorial plane CL is illustrated, but the present invention is not limited to this, and the block located in the vicinity of the tire equatorial plane CL. In addition, the same effect can be obtained by arranging the sipe rows similar to the sipe rows 6 to 8. Furthermore, if necessary, a sipe row similar to the sipe rows 6 to 8 may be arranged in another block not located on the tire equator plane CL or in the vicinity of the tire equator plane CL.

  Test pneumatic tires of various conventional examples, comparative examples and examples were manufactured, and the tread wear resistance performance, uneven wear resistance performance, snow braking performance and ice braking performance were evaluated in the same test vehicle. FIG. 4 shows various data at that time. In FIG. 4, Conventional Example 1 is used as a comparison standard (100), and the performance is improved as the index is larger than that of this comparison standard.

  Wear resistance performance and uneven wear resistance performance: Using a 2-ton light truck under loading conditions, a test tire of size 195 / 85R16, 114L is attached to a wheel of rim 5.5 to an internal pressure of 600 kPa, 80% of general road: 10 highways %: Traveled 15,000 km at a rate of 10% on a mountain road, measured the amount of wear (mm / km) at the front tire / rear tire per mileage, and compared the wear resistance performance with an index. Further, the heel & toe wear of the front tire and the center wear of the rear tire were measured on the test tires after running, and the uneven wear resistance performance was compared by an index.

  Brake performance on snow and brake performance on ice: Using a 2t light truck under loading conditions, a test tire of size 195 / 85R16, 114L was attached to a wheel of rim 5.5 to an internal pressure of 600 kPa and traveled on a general dry road for 3,000 km. After getting used to the tire surface, the vehicle traveled on snow and ice at a speed of 30 km / h, and the distance to complete stop when full braking was performed without ABS was compared and indexed.

  In Conventional Example 1, both ends of a first sipe row (corresponding to sipe row 6 in FIG. 2) arranged at both ends of the block in the tire circumferential direction communicate with the main groove, and the tire circumferential direction of the block Each one end of the second sipe row (corresponding to the sipe row 8 in FIG. 2) arranged in the intermediate portion communicates with the main groove.

  Conventional example 2 is an example in which a second sipe row (corresponding to sipe row 7 in FIG. 2) having both ends communicating with the main groove is added to the above-described conventional example 1. In this conventional example 2, the sipe length can be secured by adding the second sipe row as described above, so that the braking performance on snowy and ice roads due to the edge effect can be improved, but the wear resistance performance and uneven wear performance performance are reduced. Admitted.

  Compared to the second conventional example, the comparative example has a first sipe row (corresponding to the sipe row 6 in FIG. 2) disposed at both ends of the block in the tire circumferential direction, and the middle of the block in the tire circumferential direction. This is an example in which the second sipe row (corresponding to the sipe row 8 in FIG. 2) arranged in the section has an amplitude in the depth direction. In this comparative example, the first sipe train and the second sipe train each have an amplitude in the depth direction, thereby improving the braking performance on snow and the braking performance on ice, and in particular, having an amplitude in the depth direction. Compared with the case where the sipe is not closed, the sipe having the amplitude in the depth direction is less likely to be closed, so that the improvement of the braking performance on ice was remarkable, but the wear resistance performance and uneven wear resistance performance were reduced as compared with the first embodiment. Was recognized.

  In the embodiment, as shown in FIGS. 1 and 2, both ends of the first sipe row 6 disposed at both ends of the block 5A in the tire circumferential direction terminate in the block 5A, and the tire circumferential direction of the block 5A. The second sipe row 8 disposed in the middle portion of the second sipe row 8 has an amplitude in the depth direction, and one end thereof communicates with the main groove 2, and both ends of the second sipe row 7 communicate with the main groove 2. In this embodiment, only the uneven wear resistance performance is the same as that of the conventional example 1, but other uneven wear resistance performance, on-snow braking performance and on-ice braking performance are improved, and particularly on-ice braking performance is remarkable. An improvement was observed. Compared to Conventional Example 2, the braking performance on snow and the braking performance on ice are almost the same, but a marked improvement in uneven wear resistance and uneven wear resistance was observed. Furthermore, compared to the comparative example, both ends of the first sipe row 6 are terminated in the block 5A, so that the rigidity of both ends in the tire circumferential direction of the block 5A is increased. A significant improvement in performance was observed.

1 is a developed tread view of a pneumatic tire according to an embodiment of the present invention. 1 is an exploded view illustrating an embodiment of the present invention and showing an enlarged block of a tread surface. FIG. It is a perspective view of the cross section along the XX line of FIG. Examples of the present invention are shown, and in each traveling test course, the wear resistance performance, uneven wear resistance performance, snow braking performance, and ice braking performance of the pneumatic tires of various conventional examples, comparative examples, and examples are evaluated in the same test vehicle. It is a figure which shows the various data in that case.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread 2 Main groove 3, 3A Block row 5, 5A block 6 1st sipe row 6a, 6b Sipe 6c Dividing part 6d Short piece 7 2nd sipe row 7a, 7b Sipe 7c Dividing part 8 2nd sipe row 8a, 8b Sipe 8c Dividing part

Claims (5)

In a pneumatic tire in which a plurality of block rows are formed on a tread surface by a plurality of main grooves extending in the tire circumferential direction, and the block rows are partitioned into a plurality of blocks by lug grooves extending in the tire width direction. ,
A predetermined block formed in any one of the block rows, a first sipe row disposed at both ends in the tire circumferential direction of the block and extending in the tire width direction, and an intermediate in the tire circumferential direction of the block And a second sipe row extending in the tire width direction is provided,
The first sipe row is divided at the center of the block in the tire width direction, and both ends terminate in the block,
The pneumatic tire according to claim 2, wherein the second sipe row is divided at a central portion of the block in the tire width direction, and at least one end communicates with the main groove.   The block row in which the first sipe row and the second sipe row are formed includes a block row on a tire equator plane or a block row closest to the tire equator plane. Pneumatic tire.   3. The pneumatic tire according to claim 1, wherein the first sipe rows disposed at both ends of the block in the tire circumferential direction are sipe having amplitude in the depth direction. 4.   The pneumatic tire according to claim 3, wherein the second sipe row disposed in an intermediate portion of the block in the tire circumferential direction is a sipe that is straight in the depth direction.   5. The position at which the first sipe row and the second sipe row are divided at the center in the tire width direction is different in the tire width direction between adjacent sipe rows. A pneumatic tire according to any one of the above.

Images