JP5823153B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire (hereinafter simply referred to as “tire”) having a tread pattern having both summer performance and winter performance.

  Conventionally, as tire performance, summer performance, that is, performance that improves running on dry road surfaces (ordinary road surfaces that are not raining / snowfalling or snow-covered and not limited to summer) (hereinafter referred to as “DRY performance”). )) And winter performance, that is, performance that improves running on snowy road surfaces (hereinafter referred to as “snow performance”), and tires with better ride comfort are desired and various developments have been made. However, the actual situation is that a tire that can be fully satisfied has not yet been completed.

  For example, tires having a tread pattern shown in Patent Documents 1 to 4 below are known.

JP 7-257113 A JP 2000-21901 A Japanese Patent Laid-Open No. 11-32240 JP 2006-192929 A

  However, all the tires shown in Patent Document 1 have a pattern configuration by block rows, and a fine wavy sipe is arranged on the block surface in the inner section, and the block surface of the outer section has high bending rigidity under a lateral stress. Since the guaranteed fine sipe is arranged, there is a problem in that the envelope property (the ability to dent) is low, the shock absorption is low, and the ride comfort is deteriorated.

  The tires disclosed in Patent Document 2 all have a pattern configuration with block rows, and are all linear sipes, so that there is a problem in that the pattern rigidity is low and the snow performance is inferior.

  The tires shown in Patent Document 3 all have a pattern configuration by block rows, and a fine wavy or fine bent sipe is arranged on the block surface, and the outer side is a block configuration, so the pattern rigidity is low, and There is a problem in that the ride becomes worse.

  The tires disclosed in Patent Document 4 all have a pattern configuration with a block row and are all linear sipes, so that there is a problem in that the pattern rigidity is low and the snow performance is inferior.

  Therefore, as a result of intensive research, the present inventor has improved the ride comfort by the configuration of the asymmetric pattern and the asymmetric sipe, and also secured the DRY performance and the snow performance, thereby achieving both summer performance and winter performance. Developed the tires designed.

A tire according to the present invention is a pneumatic tire having a tread pattern including a shoulder portion formed on both sides of each main groove and a center portion sandwiched between the main grooves by at least two main grooves extending in the circumferential direction. In the center portion, a center block row in the tire circumferential direction straddling a circumferential line at the center in the tire width direction, with a single sub-groove extending in the circumferential direction, and a tire circumferential direction on the vehicle inner side of the center block row Inner center block rows are formed, and each center block in the center block row has a circum / lateral ratio of 0.70 or more, which is a ratio of the sum of the lengths in the circumstance direction and the sum of the lengths in the lateral direction. 2.75 is less that sipes formed, wavy sipes formed in each of inner intermediate block in the inner intermediate block row Is, the outer side shoulder portion formed on the outer side of the main groove in the vehicle outer side, characterized in that the linear sipe is formed.

  In the above configuration, the sipes formed in the center blocks in the center block row may be linear.

Further, in the above configuration, the sipes formed in each center block in the center block row may be wave-shaped.

Furthermore, in addition to the above-described configuration, a configuration may be adopted in which an outer media rib in the tire circumferential direction on the vehicle outer side of the center block row is formed in the center portion. In that case, it is good also as a structure by which the broken line sipe is formed in the said outside mediate rib.

  In the tire according to the present invention, the sipe in the center block row is linearized and the sipe's circum / lateral ratio in the center block row is 0.70 or more, so that the sipe is long in the circumferential direction and divided by sipe. Improve riding comfort. Moreover, the DRY performance is improved by increasing the circumferential rigidity by setting the sipe's circum / lateral ratio in the center block row to 0.70 or more. However, if the circum / lateral ratio is larger than 2.75, the balance between the circumferential rigidity of the block and the sipe arrangement is deteriorated, and it becomes difficult to achieve both the DRY performance and the ride comfort. Therefore, the circum / lateral ratio is 2.75 or less. preferable. Furthermore, the sipe in the inner mediate block block is waved to suppress a decrease in snow performance. Therefore, the tire according to the present invention suppresses a decrease in snow performance and improves DRY performance and ride comfort.

  Further, the tire according to the present invention has an advantage of improving the pattern rigidity when the outer mediate rib is formed.

1 is a partially enlarged front view of a tire according to Example 1 of the present invention. It is a part of center part of the tire which concerns on Example 1 of this invention, Comprising: (a) is a front view showing a center block, (b) is a front view showing an inner mediate block. It is explanatory drawing regarding a circumcom / lateral ratio. 4 is a partially enlarged front view of a tire according to Example 2. FIG. 6 is a partially enlarged front view of a tire according to Example 3. FIG. 2 is a partially enlarged front view of a tire according to Comparative Example 1. FIG. 5 is a partially enlarged front view of a tire according to Comparative Example 2. FIG. 10 is a partially enlarged front view of a tire according to Comparative Example 3. FIG. 10 is a partially enlarged front view of a tire according to Comparative Example 4. FIG.

  Hereinafter, preferred embodiments of the tire according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a tread pattern of a tire according to the first embodiment of the present invention. In the drawing, the left side is the inside with respect to the vehicle, and the right side is the outside with respect to the vehicle. In FIG. 1, reference numerals 1 and 2 denote main grooves extending in the circumferential direction of the tire. In the figure of the main groove 1, an inner shoulder portion 10 is defined in the left region, and in the diagram of the main groove 2, an outer shoulder portion 20 is defined in the right region. A center portion 30 is partitioned and formed in the region sandwiched between the two.

  The center portion 30 is provided with two sub-grooves 3 and 4 extending in the circumferential direction, and a center block row 31 and an inner mediate block row 32 are formed inside the vehicle with the sub-groove 3 interposed therebetween. An outer media rib 33 is formed on the outer side of the vehicle and the center block row 31 with the auxiliary groove 4 interposed therebetween. The center block row 31 is formed so as to straddle the virtual circumferential line p at the center in the tire width direction.

  The center block row 31 is divided by a right oblique groove 5 extending from the sub groove 3 to the upper right and a left oblique groove 6 extending from the sub groove 4 to the upper left, and the center blocks 31a, 31b, 31c, ... (collectively referred to as "31A"), and the center block 31A has a hexagonal arrow blade shape. As shown in FIG. 2A, three linear sipes a that cross from the upper left to the lower right are arranged in parallel on the surface of the center block 31A. This linear sipe a has a circumstance / lateral ratio of 0.97, and is 0.7 or more and 2.75 or less. The circumcom / lateral ratio is the ratio of the sum of the lengths of sipe a in the circumstance direction and the sum of the lengths in the lateral direction. Referring to FIG. 3, the horizontal (width) component of the sipe is the length in the lateral direction, the vertical (circumferential direction) component is the circum length, and the slope of the sipe is 1 when the circum / lateral ratio is 1. The angle is 45 degrees. When the circum / lateral ratio exceeds 1, the tire approaches a steep slope, that is, the circumferential direction of the tire, and when the ratio is less than 1, the slope gradually approaches a tire, that is, approaches the tire width direction. A circum / lateral ratio of 0.7 or more means that when the sum of the lengths of the sipe in the circum direction and the sum of the lengths in the lateral direction is assumed to be one sipe, the inclination angle is about 35 with respect to the width direction. That is more than a degree. Also, if the circum / lateral ratio is 2.75 or less, assuming that the sum of the sipe's total length in the direction of the sipe and the sum of the lengths in the lateral direction is one sipe, the inclination angle is relative to the width direction. It is about 70 degrees or less.

  The center block row 31 configured in this way ensures responsiveness during DRY by a linear sipe a having a circumcom / lateral ratio of 0.7 or more. Further, the center block row 31 is formed so as to straddle the virtual circumferential line p in the center in the tire width direction, which greatly affects the ride comfort, and the center block row 31 is a linear sipe disposed on the surface thereof. The total length of “a” is long, and the straight sipe “a” has an appropriate rigidity as the whole center block 31A as compared with the wavy sipe, so that the ride comfort is improved. Furthermore, by using a straight sipe a having a circumcom / lateral ratio of 2.75 or less, the balance between the circumferential rigidity of the block and the sipe arrangement can be secured, and both DRY performance and ride comfort can be achieved.

  The inner mediate block block 32 is formed by dividing the inner mediate block 32a, 32b, 32c,. The inner mediate block 32A has a shape in which the lateral groove 8 branched from the main groove 1 is deeply inserted in the center right direction. As shown in FIG. 2B, four wavy sipes b from the lower left to the upper right are arranged in parallel on the surface of the inner mediate block 32A.

  The inner mediate block row 32 configured in this manner is provided with a wavy sipe b on its surface, and more lateral grooves 7 and 8 are formed than the center block row 31, ensuring snow traction. Is done.

  The outer media rib 33 is a rib that is continuous in the circumferential direction of the tire, and is a lateral groove 9a extending from the secondary groove 4 toward the diagonally upper right to the center of the rib, and a lateral groove extending from the main groove 2 toward the obliquely lower left to the center of the rib. 9b are alternately formed in the circumferential direction, and broken line sipes c bent at the center of the rib from the upper left to the lower right are arranged at equal intervals across the rib. The inner shoulder portion 10 is formed by a substantially rectangular block row, and a wavy sipe d is disposed on the surface thereof. Further, the outer shoulder portion 20 is formed by a block row in which a substantially rectangular portion 21 is continuous, and a linear sipe e is disposed on the surface thereof.

  In the tread pattern of the tire in the second embodiment, as shown in FIG. 4, the sipe a ′ in the center block row 31 ′ has a wave shape, and other configurations are the same as those in the first embodiment.

  As shown in FIG. 5, the tread pattern of the tire according to Example 3 is that the straight sipe a ″ in the center block row 31 ″ has a circum / lateral ratio of 2.48, which is 0.7 or more and 2 The other configurations are the same as those in the first embodiment. The circum / lateral ratio is the ratio of the sum of the lengths of the sipe a in the circum direction and the sum of the lengths in the lateral direction as described in the first embodiment. When the circum-circu / ratio ratio is 1, the sipe inclination angle is 45 degrees. When the circum / lateral ratio exceeds 1, the tire approaches a steep slope, that is, the circumferential direction of the tire, and when the ratio is less than 1, the slope gradually approaches a tire, that is, approaches the tire width direction. A circum / lateral ratio of 0.7 or more means that when the sum of the lengths of the sipe in the circum direction and the sum of the lengths in the lateral direction is assumed to be one sipe, the inclination angle is about 35 with respect to the width direction. That is more than a degree. Also, if the circum / lateral ratio is 2.75 or less, assuming that the sum of the sipe's total length in the direction of the sipe and the sum of the lengths in the lateral direction is one sipe, the inclination angle is relative to the width direction. It is about 70 degrees or less.

  The center block row 31 ″ configured as described above ensures responsiveness during DRY by a linear sipe a ″ having a circum / lateral ratio of 0.7 or more. The center block row 31 '' is formed so as to straddle the virtual circumferential line p at the center in the tire width direction that greatly affects the ride comfort, and the center block row 31 '' is disposed on the surface thereof. The total length of the straight sipe a ″ is long, and the straight sipe a ″ has a moderate rigidity compared to the wave sipe, so that the ride comfort is improved. Furthermore, by using a straight sipe a ″ with a circumcom / lateral ratio of 2.75 or less, the balance between the circumferential rigidity of the block and the sipe arrangement can be secured, and both DRY performance and ride comfort can be achieved.

[Comparison test]
The tire having the tread pattern in Examples 1 to 3 described above has summer performance and winter performance, and is also satisfactory in riding comfort, and is subjected to a comparative test with the tire having the tread pattern in the following comparative example. To clarify. The tire standard used in the comparative test was 175 / 65R14, and a 1300cc class compact car (2WD) was used as the test vehicle.

[Comparative Example 1]
As shown in FIG. 6, the tread pattern of the tire in Comparative Example 1 is 0.58 where the circum / lateral ratio of the linear sipe 131a in the center block row 131 is 0.7 or less, and the inner mediate block row 132 is The straight shoulder sipe 132a is disposed on the surface, and the inner shoulder portion 110 is disposed on the surface thereof with the straight sipe 110d. The rest of the configuration is the same as that of the first embodiment. .

[Comparative Example 2]
In the tread pattern of the tire in Comparative Example 2, as shown in FIG. 7, the inner mediate block row 232 has linear sipe 232 a disposed on the surface thereof, and the inner shoulder portion 210 has an outer surface on the surface. A straight sipe 210d is arranged, and other configurations are the same as those in the first embodiment.

[Comparative Example 3]
As shown in FIG. 8, the tread pattern of the tire in Comparative Example 3 is 0.58 in which the circum / lateral ratio of the sipe 331a in the center block row 331 is 0.7 or less, and is a wavy sipe. The block row 332 is provided with a straight sipe 332a on the surface thereof, and the inner shoulder portion 310 is provided with a straight sipe 310d on the surface thereof, and other configurations are the same as those in the first embodiment. To do.

[Comparative Example 4]
As shown in FIG. 9, in the tread pattern of the tire in Comparative Example 4, the center block row 431 has a straight sipe 431a disposed on the surface thereof, and the sipe 431a has a circum / lateral ratio of 2.75 or more. .90, and the rest of the configuration is the same as that of the first embodiment.

  The results of the comparative test are shown in Table 1 below. The test items are indicated as “DRY”, “riding comfort” and “snow” in Table 1 below. “DRY” in Table 1 is a score obtained by sensory evaluation on an actual vehicle on a dry road surface and indexed, and a larger index is better. “Riding comfort” in Table 1 is a score obtained from an actual vehicle sensory evaluation on a dry road surface and indexed, and a larger index is better. “Snow” in Table 1 is a score obtained from an actual sensory evaluation on a snowy road, indexed, and a larger index is better. The reference value for indexing is that of Comparative Example 1, and the index is 100.

  As a result of the comparison test, first, in Table 1, it is examined how “DRY”, “riding comfort”, and “snow” change when the circumstance / lateral ratio on the Ce portion Ce side is changed. Comparing Comparative Example 1 and Comparative Example 2, if the circumstance / lateral ratio on the Ce portion Ce side is increased from 0.58 to 0.97 of 0.70 or more, “DRY” is increased from 100 to 105, "Is improved from 100 to 103, and" Snow "is decreased from 100 to 97. Further, when Example 1 and Example 3 are compared, if the circumstance / lateral ratio on the Ce portion Ce side is increased from 0.97 to 2.48 within the range of 0.70 to 2.75, “DRY” becomes From 104 to 102, “riding comfort” decreases from 102 to 100, and “snow” decreases from 106 to 105. Furthermore, when Example 3 and Comparative Example 4 are compared, if the circumstance / lateral ratio on the Ce portion Ce side is increased from 2.48 to 2.90 of 2.75 or more, “DRY” is increased from 102 to 99, “ Both “riding comfort” from 100 to 97 and “snow” from 105 to 103 are further reduced.

  From the above results, “DRY” and “Riding comfort” have a peak when the Circum / Lateral ratio on the Ce portion Ce side is slightly lower than 0.97, and decrease before and after the numerical value decreases or increases. However, in the range of 0.70 to 2.75, it exceeds the standard value of 100, and it can be said that summer performance and ride comfort are not inferior. On the other hand, with regard to “snow”, it can be said that the higher the circumstance / lateral ratio on the Ce portion Ce side, the lower it is.

  Next, it is examined how “DRY”, “riding comfort”, and “snow” change when the sipe form on the block surface is changed. Comparing Example 2 and Example 1, if the sipe on the Ce portion Ce side is changed from a wave shape to a linear shape, “DRY” is slightly decreased from 106 to 104, and “Snow” is slightly decreased from 107 to 106. "Riding comfort" is improved from 100 to 102. The same can be said when Comparative Example 3 is compared with Comparative Example 1. Further, comparing Comparative Example 2 and Example 1, if the sipe on the Ce portion IN side is changed from a linear shape to a wavy shape, “DRY” is slightly decreased from 105 to 104, and “riding comfort” is slightly decreased from 103 to 102. However, “Snow” has improved significantly from 97 to 106.

  From this result, it is possible to improve the “riding comfort” if the sipe on the Ce portion Ce side and Ce portion IN side on the block surface is linear, but if the sipe on the Ce portion Ce side is linear, “DRY” It can be said that “Snow” is slightly reduced. On the other hand, when the sipe on the Ce portion IN side is wave-shaped, “DRY” is slightly reduced, but “snow” is greatly improved.

  As a result of the above, summer performance and ride comfort are improved by designing the center block row to have a circum / lateral ratio in the range of 0.70 to 2.75, and the sipe of the center block row is made linear. The ride performance is improved, and the winter performance, which has been reduced due to the design of the circum-circular / lateral ratio of the center block row within the range of 0.70 to 2.75, the sipe of the inner mediate block row is made wavy. By doing so, it is possible to obtain a tire that is well balanced as a whole, has summer performance and winter performance, and has excellent riding comfort.

  Therefore, in the tire of Example 1, the sipe in the center block row was made linear, and the circum / lateral ratio of the sipe in the center block row was set to 0.97 within the range of 0.70 to 2.75. Riding comfort is improved. In addition, the DRY performance, which has been reduced by straightening the sipe in the center block row, is improved by setting the sipe's circum / lateral ratio in the center block row to 0.97 within the range of 0.70 to 2.75. I am letting. Furthermore, the decrease in snow performance due to the sipe in the center block row being linear and the sipe's circum / lateral ratio in the center block row being 0.97 within the range of 0.70 to 2.75. This is suppressed by making the sipe in the eight block row wavy. Therefore, it can be said that the tire of Example 1 is a tire in which the decrease in snow performance is suppressed and the DRY performance and riding comfort are improved.

  Moreover, the tire of Example 2 has improved the DRY performance and the snow performance by making the sipes in the center block row and the inner mediate block row into a wave shape. And about the riding comfort of the tire of Example 2, the reduction | decrease by making the sipe in the center block row | line | column and the inner mediate block row | line | column wavy was used, and the circum / lateral ratio of the sipe in the center block row | line | column was 0.70-2. It is suppressed by setting it to 0.97 within the range of 75.

  Further, in the tire of Example 3, the sipe in the center block row was linearized, and the sipe's circum / lateral ratio in the center block row was 2.48 within the range of 0.70 to 2.75. Riding comfort is improved. In addition, the DRY performance, which has been reduced by making the sipe in the center block row linear, has been improved by setting the sipe's circum / lateral ratio in the center block row to 2.48 within the range of 0.70 to 2.75. I am letting. In addition, the decrease in snow performance due to the sipe in the center block row being linear and the sipe's circum / lateral ratio in the center block row being 2.48 within the range of 0.70 to 2.75. This is suppressed by making the sipe in the eight block row wavy.

  Further, the tires in Examples 1 to 3 have the advantage of improving the pattern rigidity because the outer mediate ribs 33 are ribs continuous in the circumferential direction of the tire, and are folded at the rib center from the upper left to the lower right. Since the bent broken line sipes c are arranged at equal intervals across the rib, there is an advantage of improving the DRY performance.

  In addition, when the pneumatic tire according to the present invention is mounted on a vehicle with the inner side and the outer side reversed, the effect based on the configuration of the present invention is not achieved, but it does not hinder the traveling of the vehicle. Absent.

  Note that the tire according to the present invention is not limited to the above-described embodiments, and various embodiments are possible without departing from the structure described in the claims.

DESCRIPTION OF SYMBOLS 1 ... inner main groove 2 of a tread part ... outer main groove 3 of a tread part ... inner side sub groove 4 of a center part ... outer side sub groove 5 of a center part ... center Right oblique groove 6 in the center part ... Left oblique groove 7 in the center part ... Horizontal groove 8 in the inner mediate block row ...... Horizontal groove 9a in the inner mediate block ... Lateral groove 9b ... Lateral groove 10 on the outer mediate rib ... Inner shoulder d ... Sipes (wavy) on the inner shoulder
20 ... Outer shoulder 21 ... Consecutive part of outer shoulder e ... Sipes of outer shoulder (straight)
30 ... Center part 31 ... Center block row p ... Virtual circumferences 31A, 31a, 31b, 31c ... Center block a ... Sipes of the center block (linear)
32 ... Inner mediate block row 32A, 32a, 32b, 32c ... Inner mediate block b ... Sipes (wavy) of inner mediate block
33 ... Outside mediatorive c ... Outside mediate sipe (folded line)
a '... Sipe of the center block (wavy)
31 '・ ・ Center block row a''・ ・ Sipe of center block (straight)
31 ″, center block row 131, center block row 131a, center block row sipe (straight)
132 ·· Inner mediate block row 132a · Inner mediate block row sipe (straight)
110 ·· Inner shoulder 110d · Inner shoulder sipe (straight)
232 .. Inside mediate block row 232a. Inside mediate block row sipe (straight)
210 ·· Inner shoulder 210d · Inner shoulder sipe (straight)
331 ·· Center block row 331a · Center block row sipe (wavy)
332 .. Inside mediate block row 331a. Inside mediate block row (straight)
310 ·· Inner shoulder 310d · Inner shoulder sipe (straight)
431 ·· Center block row 431a · Center block row sipe (straight)

Claims (5)

In a pneumatic tire having a tread pattern including a shoulder portion formed on both sides of each main groove and a center portion sandwiched between the main grooves by at least two main grooves extending in the circumferential direction,
A center block row in the tire circumferential direction straddling a circumferential line in the center in the tire width direction with a single sub-groove extending in the circumferential direction in the center portion, and an inner side in the tire circumferential direction on the vehicle inner side of the center block row A mediate block row is formed,
Each center block in the center block row is formed with a sipe having a circum / lateral ratio of 0.70 or more and 2.75 or less, which is a ratio of a sum of lengths in the circumstance direction and a sum of lengths in the lateral direction,
A wavy sipe is formed in each inner mediate block in the inner mediate block row,
A pneumatic tire is characterized in that a linear sipe is formed in an outer shoulder portion formed outside the main groove on the vehicle outer side.   The pneumatic tire according to claim 1, wherein sipes formed in the center block are linear.   The pneumatic tire according to claim 1, wherein a sipe formed in the center block is wavy.   2. The pneumatic tire according to claim 1, wherein an outer media rib in the tire circumferential direction on the vehicle outer side of the center block row is formed in the center portion.   The pneumatic tire according to claim 4, wherein a polygonal sipe is formed on the outer mediate rib.

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