JP2006315433A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire good in driving and braking performance on both of a wet road surface and an ice/snow road surface by arranging a plurality of peripheral grooves including a see-through groove part, in particular, and optimizing a prescribed center land part row. <P>SOLUTION: A wide center land part row 6 and a narrow center land part row 5 are sectioned and formed by arranging a center peripheral groove 2 and a pair of side peripheral grooves 3 and 4. A first side land row 13 is formed by arranging many first intersecting grooves 9 extending from a first tread end 7 till opening in the center peripheral groove 2. The narrow center land part row 5 is made as a center block row. A second side land part row 14 is formed by arranging a second intersecting groove 10 extending from a second tread end 8 till opening in a second side peripheral groove 4. In all the land part rows 5, 6, 13 and 14, a plurality of lateral sipes 15a to 15d are arranged. The wide center land part row 6 has a bent narrow groove 16 bending and extending at prescribed peripheral direction pitch P1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a central circumferential groove including a see-through groove portion that is located in the tire equator region and extends linearly along the tire circumferential direction, and is located on both sides of the central circumferential groove at different tire width direction distances in the tire circumferential direction. A pneumatic tire having an asymmetric tread pattern, in which a pair of side circumferential grooves including a see-through groove portion extending linearly along a straight line is provided to define a wide central land row and a narrow central land row In particular, the present invention relates to a winter (studless) tire excellent in driving and braking performance on both wet and icy and snowy road surfaces.

  A conventional studless tire having such an asymmetric tread pattern has a plurality of straight circumferential grooves extending linearly along the tire circumferential direction as described in Patent Document 1, for example, when drainage performance is important. This arrangement is useful. However, since the arrangement of the straight circumferential groove does not contribute to an increase in the edge component extending in the tire width direction, there is a problem that the driving / braking performance on the icy and snowy road surface cannot be sufficiently obtained.

In addition, when emphasizing ice and snow performance, for example, as described in Patent Document 2,
It is useful to arrange a plurality of zigzag circumferential grooves that bend and extend along the tire circumferential direction. However, the arrangement of the zigzag circumferential grooves has a problem that the drainage performance is inferior to that of the straight circumferential grooves.

Furthermore, in order to satisfy both drainage and ice / snow performance in a well-balanced manner, it may be possible to arrange both straight circumferential grooves and zigzag circumferential grooves in combination. It is difficult to balance the two at a high level.
JP-A-8-197912 JP 2001-322408 A

  An object of the present invention is to arrange a plurality of circumferential grooves including a see-through groove portion extending linearly along the tire circumferential direction, and to effectively optimize the edge of a predetermined central land portion row to effectively remove edge components. It is an object to provide a pneumatic tire excellent in driving and braking performance on both a wet road surface and an icy / snow road surface.

  In order to achieve the above object, the present invention provides a central circumferential groove including a see-through groove portion located in the tire equator region and extending linearly along the tire circumferential direction, and different tire width direction distances on both sides of the central circumferential groove. And a pair of lateral circumferential grooves including a see-through groove portion that extends linearly along the tire circumferential direction, and the central circumferential groove and the pair of lateral circumferential grooves narrow the wide central land row. A plurality of first transverse grooves extending from the first tread end closer to the narrow central land portion row to the central circumferential groove are disposed to define the width central land portion row, and the first tread A first side land portion row composed of a number of first side blocks is formed between the end and the first side circumferential groove closer to the end, and a plurality of the narrow central land portion rows are formed. The second block closer to the wide central land row is the central block row consisting of the central blocks. A second transverse groove extending from the red end to the second second circumferential groove closer to the second end is disposed, and a plurality of second transverse grooves are provided between the second tread end and the second lateral circumferential groove. A second side land portion row formed of side blocks is formed, and each of the land portion rows is provided with a plurality of horizontal sipes in a substantially width direction, and the wide center land portion row has a substantially center width. It is a pneumatic tire characterized by having a bent narrow groove extending at a predetermined circumferential pitch along the tire circumferential direction.

  Further, (1) the bent narrow groove has a groove width that closes under a predetermined internal pressure and load condition, and (2) the bent central groove is located closer to the wide central land portion row than the bent position of the bent narrow groove. An auxiliary groove opening in the circumferential groove is disposed, and the wide central land portion row is substantially divided into two block land portion rows by the bent narrow groove and the auxiliary groove, and (3) the bent groove is bent. The distance between the positions of the peaks and valleys as measured along the tire width direction is in the range of 0.15 to 0.7 times the width of the wide central land portion row; The circumferential pitch of the grooves is smaller than the arrangement pitch of the lateral transverse grooves. (5) The circumferential pitch of the bent narrow grooves is 1/2 or 1/3 of the arrangement pitch of the lateral transverse grooves. And / or the transverse grooves located in the narrow central land row have narrow grooves that close when the tire is loaded. It is more suitable.

  According to the present invention, in particular, a plurality of circumferential grooves including a see-through groove portion extending linearly along the tire circumferential direction are disposed, and an appropriate edge component is effectively obtained by optimizing a predetermined central land portion row. By increasing the number, it has become possible to provide a pneumatic tire with excellent driving and braking performance on both wet and icy road surfaces.

  FIG. 1 shows a part of a tread pattern of a pneumatic tire according to the present invention.

  A pneumatic tire having a tread portion 1 shown in FIG. 1 includes a central circumferential groove 2 including a see-through groove portion located in the tire equator region and extending linearly along the tire circumferential direction C, and on both sides of the central circumferential groove 2. A pair of side circumferential grooves 3 and 4 including a see-through groove portion positioned at different tire width direction distances and extending linearly along the tire circumferential direction C, and the central circumferential groove 2 and the lateral circumferential grooves. A narrow central land row 5 and a wide central land row 6 are partitioned by 3 and 4.

  The “tire equator region” here means specifically a region within 20% of the tread width centering on the tire equator. The central circumferential groove 2 and the lateral circumferential grooves 3 and 4 are limited to the configuration including the “see-through groove portion” from the viewpoint of ensuring drainage. These circumferential grooves 2 to 4 are, for example, zigzag grooves. Even so, it means that at least a part of the circumferential grooves 2 to 4 may be a see-through groove portion. In FIG. 1, the center circumferential groove 2 and the side circumferential grooves 3 and 4 both show a case where the entire groove is a see-through groove.

  Also, a plurality of first transverse grooves 9 extending from the first tread end 7 closer to the narrow central land row 5 to the central circumferential groove 2 are disposed, and the first tread end 7 and the first tread end 7 are arranged. A first side land portion row 13 composed of a number of first side blocks 11 between the first side circumferential groove 3 and the narrow side central land portion row 5. A second transverse groove 10 extending from the second tread end 8 closer to the wide central land portion row 6 to the second side circumferential groove 4 closer to the central block row made up of a plurality of central blocks 19. Between the second tread end 8 and the second side circumferential groove 4 to form a second side land portion row 14 composed of a plurality of second side blocks 12, Each of the land rows 5, 6, 13, and 14 also has a substantially width direction (specifically, a direction within an angle range of ± 30 ° with respect to the tire width direction). A plurality of extending horizontal sipes 15a to 15d are provided.

  In the present invention, ice / snow performance can be ensured by forming a large number of blocks and arranging sipes in the tread portion.

  In the present invention, in addition to the above configuration, a bent narrow groove 16 that is bent and extended at a predetermined circumferential pitch P1 along the tire circumferential direction C is provided at a substantially central position in the width of the wide central land portion row 6. In particular, by adopting such a configuration, it is possible to satisfy both drainage performance and ice / snow performance at a high level.

  The pneumatic tire according to the present invention has a wide central land portion row with the first tread region 17 including the narrow central land portion row 5 on the inner side of the vehicle, particularly with respect to the central circumferential groove 2 in the vehicle mounting posture of the tire. The second tread region 18 including 6 is arranged on the outside of the vehicle, and the performance required for the tire, for example, individual performance such as steering stability performance, drainage performance and ice / snow performance, is provided in the respective tread regions 17 and 18. The tread pattern is configured so as to be divided and burdened.

  For example, in FIG. 1, the first tread region 17 located inside the vehicle has a pattern configuration suitable for exhibiting drainage performance and snow performance, while the second tread region 18 located outside the vehicle has steering stability and The case where it is set as the pattern structure suitable for exhibiting the performance on ice is shown.

  That is, the central circumferential groove 2 is disposed at a position shifted from the tire equator EL toward the vehicle inner side, and the tread portion 1 is formed by a narrow first tread between the central circumferential groove 2 and the tread ends 7 and 8. An asymmetric pattern is formed in the tread portion 1 by dividing the region 17 into a wide second tread region 18. Since the central circumferential groove 2 and the lateral circumferential grooves 3 are disposed on the vehicle inner side than the tire equator EL, sufficient drainage performance can be obtained in the first tread region 17 located on the vehicle inner side. it can.

Each of the first side land portion row 13 and the narrow central land portion row 5 in the first tread region 17 located on the vehicle inner side is constituted by a block row made up of a number of blocks, and each block Since the plurality of horizontal sipes 15a and 15b are disposed in the first tread region 17 located on the inner side of the vehicle, sufficient on-snow performance can be obtained.
However, when the sipes are disposed, the block rigidity is lowered. In particular, if the rigidity of the block 19 located in the narrow central land portion row 5 in the tread region 17 located inside the vehicle is excessively lowered, the central circumferential groove 2 is formed. As a result, the rigidity balance with the land portion in the tread region 18 located outside the vehicle is deteriorated.

  For this reason, the transverse groove 9 located in the central land portion row 5 in the tread region 17 located on the inner side of the vehicle has a narrow groove portion 22 (specifically, 0.5 to 4 mm) that is closed at the time of tire load rolling. As a result, the blocks 19 positioned in the central land portion row 5 of the first tread region 17 support each other and the rigidity can be prevented from being lowered. As a result, the rigidity balance with the land portion in the second tread region 18 positioned outside the vehicle is achieved. It is preferable because the performance on snow can be effectively improved without deteriorating the temperature.

  Further, according to the present invention, the bent narrow groove 16 that is bent and extended at a predetermined circumferential pitch P1 along the tire circumferential direction is disposed at a substantially central position in the width of the wide central land portion row 6 located outside the vehicle. As a result, the edge component, especially the width direction edge component, can be effectively increased without significantly reducing the rigidity compared to the case where a straight circumferential groove is provided. As a result, sufficient steering stability and ice / snow performance are achieved. (In particular, driving / braking performance and cornering performance) can be obtained.

  The bent narrow groove 16 preferably has a groove width that closes under predetermined internal pressure and load conditions, and preferably has a groove width of 0.1 to 4 mm, from the viewpoint of securing the rigidity of the land portion. Note that the “predetermined internal pressure and load conditions” mentioned here specifically refers to the application size described in the following standard when the tire is mounted on a rim in the application size described in the following standard. This means the condition under which the air pressure and the maximum load (maximum load capacity) corresponding to the maximum load (maximum load capacity) of a single wheel are applied.

  The standard is determined by an industrial standard effective in the region where the tire is produced or used. For example, “Year Book of The Tire and Rim Association Inc.” in the United States, “Standards Manual of The European Tire and Rim Technical Organization” in Europe, and “JATMA Year Book” of the Japan Automobile Tire Association in Japan. It is prescribed.

  Further, auxiliary grooves 24 that open from the bent position of the bent narrow grooves 16 to the peripheral grooves 2 and 4 closer to the bent narrow grooves 16 are disposed in the wide central land portion row 6, and these bent narrow grooves 16 and auxiliary grooves 24 are arranged. Thus, it is preferable to partition the wide central land portion row 6 into substantially two block land portion rows 25 and 26 from the viewpoint of increasing the edge component and improving the snow and snow performance.

  In the case where an auxiliary groove is provided in the wide central land portion row 6 and is divided into two rows of block land portion rows 25 and 26 substantially consisting of a large number of pseudo blocks 27 and 28, the bent groove 16 is provided. The distance P2 when measured along the tire width direction W between the peak position X and the valley position Y, which is the bending position, is in the range of 0.15 to 0.7 times the width W1 of the wide central land row 6. It is preferable to do. This is because if the distance P2 is less than 0.15 times the width W1, the edge component cannot be increased effectively, and improvement in ice / snow performance due to the edge effect tends not to be expected. If P2 exceeds 0.7 times the width W1, the corners of the pseudo blocks 27 and 28 become sharp corners at the bent position, and the rigidity of the land portion decreases, resulting in ice / snow performance, dry road surfaces, and wet road surfaces. This is because the steering stability may be reduced.

  The circumferential pitch P1 of the bent narrow grooves 16 is preferably smaller than the arrangement pitch P3 of the lateral transverse grooves 10, and in particular, 1/2 or 1/3 of the arrangement pitch P3 of the lateral transverse grooves 10. Is more preferred. In order to suppress the deterioration of drainage, the block row to be zigzag is minimized, and instead, the circumferential pitch of the zigzag is smaller than the arrangement pitch P3 of the side transverse grooves 10, preferably, By setting 1/2 to 1/3, the edge component of this portion can be set to substantially 2 to 3 times, and the same edge as when 2 to 3 circumferential grooves are zigzag bent grooves The effect can be obtained effectively without impairing drainage. This is because if the circumferential pitch P1 is larger than ½ of the arrangement pitch P3, it tends to be difficult to increase the edge effect to the expected level. This is because the block rigidity of the vehicle may decrease, and the running performance on dry road surfaces, wet road surfaces, and icy and snowy road surfaces may deteriorate. For this reason, in the present invention, the circumferential pitch P1 is preferably set to 1/2 to 1/3 of the arrangement pitch P3 of the lateral transverse grooves 10. However, if the setting is fine in such a range, the pattern setting is complicated. (In particular, it is difficult to set the number of pitches.) Therefore, it is particularly effective in practice to set to 1/2 or 1/3 of the arrangement pitch P3 of the lateral transverse grooves 10.

  Further, the side block 12 constituting the side block row 14 located outside the vehicle has a width dimension W2 measured along the tire width direction W that constitutes the side block row 13 located inside the vehicle. Making the width of the side block 11 longer than the width dimension W3 can increase the rigidity in the tire width direction of the side block 12 located on the outer side of the vehicle. As a result, the side block 12 that is most heavily loaded during cornering travels. It is preferable in that the grip force can be enhanced and the cornering performance can be improved.

  In addition, the groove width W4 of the transverse groove 10 disposed in the lateral land portion row 14 of the tread region 18 located outside the vehicle is disposed in the lateral land portion row 13 of the tread region 17 located inside the vehicle. If it is made narrower than the groove width W5 of the transverse groove 9, the ground contact area at the lateral land portion row 14 outside the vehicle can be increased, and as a result, the performance on ice can be improved.

  However, if the rigidity in the tire width direction of the side land portion row 14 located on the vehicle outer side is excessively increased, the side block 12 tends to deteriorate the uneven wear resistance.

  For this reason, in such a configuration, the side block 12 positioned on the outer side of the vehicle has a continuous sipe in a substantially tire circumferential direction at a substantially central position in the tire width direction W, or intermittently as shown in FIG. By disposing the longitudinal sipe 29 that extends in a straight line, the side block 12 can be divided into two block parts in a pseudo manner, thereby suppressing an excessive increase in the rigidity of the land portion. Uneven wear is improved, and in addition, braking performance on wet road surfaces can be improved.

  The above description is merely an example of the embodiment of the present invention, and various modifications can be made within the scope of the claims. The bent narrow groove 16 only needs to be configured so as to effectively increase the edge component. In addition to the zigzag shape shown in FIGS. 1 and 2A, a square wave as shown in FIG. The extended shape of a trapezoidal wave as shown in FIG.

Next, a pneumatic tire according to the present invention was prototyped and performance evaluation was performed, which will be described below.
Example 1
The tire of Example 1 has the tread pattern shown in FIG. 1, the tire size is 205 / 65R15, the negative rate of the entire tread is 27%, and the negative rate of the tread half-width region located inside the vehicle is 31.4. %, And the negative rate of the tread half-width region located outside the vehicle was 22.9%. The groove width of the central circumferential groove 2 was 10 mm, the groove widths of the side circumferential grooves 3 and 4 were 6 mm and 5 mm, respectively, and the width dimensions of the side blocks 11 and 12 were 34 mm and 40 mm, respectively. The groove width of the bent narrow groove is 2.5 mm, the distance P2 of the bent groove is 0.32 times the width W1 of the wide central land portion row, and the circumferential pitch P1 of the bent narrow groove is the arrangement pitch of the lateral transverse grooves. It was set to 1/2 of P3. The auxiliary groove 24 has a groove width of 5 mm, the lateral transverse groove 9 has a groove width of 6.5 mm at the side land portion row 13 position, 5 mm at the narrow central land portion row position 5 (2.5 mm at the narrow groove portion 22 position). ), The groove width of the lateral transverse groove 10 was set to 5.5 mm. The tire structure other than the tread pattern was the same as that of a normal pneumatic radial tire for passenger cars.

Comparative Example The comparative example has the tread pattern 101 shown in FIG. 3, the tire size is 205 / 65R15, the negative rate of the entire tread is 27.1%, and the negative rate of the tread half-width region located inside the vehicle is The negative rate of the tread half-width region located outside the vehicle was set to 23.88%. The groove widths of the four circumferential main grooves 102 to 105 were 7 mm, 9 mm, 4.5 mm, and 5.5 mm, respectively, and the width dimensions of the side blocks 106 and 107 were 30 mm and 33 mm, respectively. The groove widths of the lateral transverse grooves 108 and 109 were 6 mm and 6 mm, respectively.

(Performance evaluation)
(1) Wet Maneuvering Stability Evaluation Test Wet maneuvering stability was evaluated by measuring the limit speed at which a hydroplaning phenomenon occurred on a wet road surface with a water depth of 5 mm and measuring the limit speed.

(2) Steering stability evaluation test on compressed snow Steering stability on compressed snow is determined by braking performance, acceleration, straightness, and cornering by a test driver when traveling in various driving modes on a test track on a compressed snow road. This was done by comprehensively evaluating the feeling.

(3) Brakeability evaluation test on snow pressure The braking performance on snow pressure was evaluated from the measured braking distance by measuring the braking distance when full braking was performed on the snowy road surface from running at 40 km / h.

(4) Drivability evaluation test on the snow pressure The drive performance on the snow pressure was evaluated from the measured time by fully accelerating the surface of the snow pressure and measuring the time to reach a distance of 50 m.

(5) Steering stability evaluation test on ice plate Steering stability on ice plate is determined by braking performance, acceleration performance, straight running performance by test driver when traveling on various test modes on ice plate road surface. The cornering properties were evaluated by comprehensively evaluating the feeling.

(6) Evaluation test of braking performance on ice plate The braking performance on ice plate was evaluated from the measured braking distance by measuring the braking distance when full braking was performed from the traveling speed of 20 km / h on the ice plate road surface. .

From the evaluation results shown in Table 1, the example is superior in handling stability and driving / braking performance on both wet and icy and snowy road surfaces as compared with the comparative example.

  According to the present invention, in particular, a plurality of circumferential grooves including a see-through groove portion extending linearly along the tire circumferential direction are disposed, and an appropriate edge component is effectively obtained by optimizing a predetermined central land portion row. By increasing the number, it has become possible to provide a pneumatic tire with excellent driving and braking performance on both wet and icy road surfaces.

FIG. 3 is a development view of a part of the tread portion of the pneumatic tire according to the present invention. It is the figure which showed notionally various extension shapes of a bending thin groove. It is a partial development view of the tread part used for the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Center circumferential groove 3, 4 Side circumferential groove 5 Narrow center land part row | line | column 6 Wide center land part row | line | column 7 1st tread end 8 2nd tread end 9 1st transverse groove 10 2nd transverse groove 11 1st Side block 12 Second side block 13 First side land portion row 14 Second side land portion row 15a to 15d Horizontal sipe 16 Bent narrow groove 17 First tread region 18 Second tread region 19 Block 22 Narrow groove portion 24 Auxiliary groove 25, 26 Block land row 27, 28 Pseudo block 29 Vertical sipe

Claims (7)

A central circumferential groove including a see-through groove portion that is located in the tire equator region and linearly extends along the tire circumferential direction, and is located on both sides of the central circumferential groove at different tire width direction distances and linear along the tire circumferential direction. A pair of side circumferential grooves including a see-through groove portion extending to the center circumferential groove and the pair of side circumferential grooves to form a wide central land portion row and a narrow central land portion row,
A plurality of first transverse grooves extending from the first tread end closer to the narrow central land row to the center circumferential groove are disposed, and the first tread end and the first side closer thereto are arranged. A first side land portion row composed of a number of first side blocks is formed between the circumferential groove and the narrow central land portion row is defined as a center block row composed of a number of center blocks. ,
A second transverse groove extending from the second tread end closer to the wide central land portion row to open to the second side circumferential groove closer to the second central tread portion row is disposed, and the second tread end and the second lateral side are arranged. Forming a second side land portion row composed of a number of second side blocks between the circumferential grooves,
In each land part row, a plurality of horizontal sipes are arranged in a substantially width direction,
2. The pneumatic tire according to claim 1, wherein the wide central land portion row has bent narrow grooves extending at a predetermined circumferential pitch along a tire circumferential direction at a substantially central position in the width. 2. The pneumatic tire according to claim 1, wherein the bent narrow groove has a groove width that closes under predetermined internal pressure and load conditions. In the wide central land portion row, an auxiliary groove that opens from a bent position of the bent narrow groove to a circumferential groove closer to the bent thin groove is disposed, and the wide central land row is substantially formed by the bent narrow groove and the auxiliary groove. The pneumatic tire according to claim 1, which is partitioned into two rows of block land portions. The distance when the distance between the peak and valley positions, which are the bent positions of the bent grooves, is measured along the tire width direction is in a range of 0.15 to 0.7 times the width of the wide central land row. 2. A pneumatic tire according to 2 or 3. The pneumatic tire according to any one of claims 1 to 4, wherein a circumferential pitch of the bent narrow grooves is smaller than an arrangement pitch of the lateral transverse grooves. The pneumatic tire according to claim 5, wherein the circumferential pitch of the bent narrow grooves is ½ or 配 設 of the arrangement pitch of the lateral transverse grooves. The pneumatic tire according to any one of claims 1 to 6, wherein the transverse groove located in the narrow central land portion row has a narrow groove portion that is closed when the tire is loaded and rolled.

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