JP2006168379A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of securing the running performance such as the accelerating performance, straight running performance, etc. on an icy/snowy road, and enhancing the driving stability, in particular the cornering performance. <P>SOLUTION: A buttress part 16 whose two ends consist of a grounding end part contacting the road surface by the tread part 15 and a buttress end part positioned in the center from the grounding end part to the tire maximum width part is equipped with at least one groove 17 stretching in the tire circumferential direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire, and relates to a pneumatic tire having driving performance such as acceleration performance and straight running performance on icy and snowy roads, and steering stability performance, particularly cornering performance.

 In recent years, various proposals have been made on pneumatic tires used on icy and snowy roads, with the prohibition of use of spike tires having metal fittings (studs and the like) in the tread portion.

For example, the tread portion includes a plurality of blocks defined by a plurality of main grooves formed in the tire circumferential direction and a plurality of sub-grooves formed in the tread width direction, and the block is formed in the tire circumferential direction. A pneumatic tire provided with a sipe is disclosed (for example, Patent Document 1). According to this pneumatic tire, since the above-mentioned sipe is formed in the tire circumferential direction, the grip performance when the vehicle turns is improved, so that the steering stability performance on ice and snow roads, particularly the cornering performance is improved. be able to.
JP-A-7-81319 (first page-second page, Fig. 1)

  However, in the conventional pneumatic tire described above, the steering stability performance is improved, but the sipe is formed in the tire circumferential direction, so that the contact area to the road surface is reduced, and the acceleration performance is lowered. Moreover, since the rigidity is reduced due to the formation of the sipe, the straight running performance is deteriorated. Further, there is a trade-off between steering stability performance and straight running performance, and a technology that achieves both of these traveling performances has been desired.

  Accordingly, the present invention has been made in view of the above-described problems, and a pneumatic tire that ensures driving performance such as acceleration performance and straight running performance on icy and snowy roads and improves steering stability performance, particularly cornering performance, is provided. The purpose is to provide.

 In order to solve the above problems, the pneumatic tire according to the present invention is characterized in that a tread portion is in contact with a road surface at a tread portion, and a paddle end portion is a central position from the ground end portion to the tire maximum width portion. The both ends have a groove portion having at least one groove along the tire circumferential direction, and the groove has a groove depth that is a depth in the tire radial direction and a groove width that is a width in the tread width direction. This is the gist.

  According to this invention, since the groove portion is provided in the tire circumferential direction in the padless portion, the lateral grip performance can be enhanced, and thus the steering stability performance, particularly cornering performance can be improved. Further, in comparison with the prior art in which the sipe formed in the tire circumferential direction is provided in the tread portion, the present invention does not form the sipe in the tire circumferential direction in the ground contact portion in contact with the road surface in the tread portion. Therefore, acceleration performance and straight running performance can be ensured.

  Moreover, the groove depth in the pneumatic tire according to the feature of the present invention may be arranged to be 0.5 mm to 1.5 mm.

  According to this invention, since the groove depth can be ensured when the groove depth is 0.5 mm to 1.5 mm, the durability of the tire can be improved. Moreover, since the role of an edge is further improved because groove depth is 0.5 mm-1.5 mm, the grip performance of a horizontal direction can be improved. When the groove depth exceeds 1.5 mm, there is a concern that the rigidity of the groove portion is lowered. Further, if the groove depth is less than 0.5 mm, there is a concern that the role of the edge is lowered.

  Moreover, the groove width in the pneumatic tire according to the feature of the present invention may be arranged to be 0.5 mm to 1.5 mm.

  According to this invention, when the groove width is 0.5 mm to 1.5 mm, the rigidity of the groove portion can be further ensured, so that the durability of the tire can be improved. Moreover, since the role of an edge is further improved when the width | variety of a groove | channel is 0.5 mm-1.5 mm, the grip performance of a horizontal direction can be improved. If the groove width exceeds 1.5 mm, there is a concern that the rigidity of the groove portion is reduced. Further, if the groove width is less than 0.5 mm, there is a concern that the role of the edge is lowered.

  Further, the plurality of grooves constituting the groove portion in the pneumatic tire according to the feature of the present invention may be arranged so that the groove depth becomes deeper in steps from the ground contact end portion to the padless end portion.

 According to such an invention, when the pneumatic tire comes into contact with the end of the tread portion and the end of the pneumatic tire at the tread portion, the depth of the groove is gradually increased from the vicinity of the end of the ground contact to the end of the paddle. Since the role of the edge is increased even with the deformation when it is grounded, the grip performance can be further improved.

 Further, the groove depth in the pneumatic tire according to the feature of the present invention may be arranged such that the grounding end side is 0.5 mm to 1.0 mm and the badless end side is 1.0 mm to 1.5 mm. Good.

 According to this invention, when the depth of the groove on the ground contact end side is 0.5 mm to 1.0 mm, the durability of the pneumatic tire can be further improved and an edge can be played. If the depth of the groove on the ground contact end side exceeds 1.0 mm, there is a concern that the rigidity of the ground contact end will be lowered, and the durability of the tire will be reduced, such as cracking at the bottom of the groove on the ground contact end. There is concern. In addition, if the depth of the groove on the ground contact end side is less than 0.5 mm, the role of the edge may be reduced.

 Moreover, the depth of the groove | channel on the side of a padless edge part can play the role of the further improvement of durability of a pneumatic tire, and an edge because it is 1.0 mm-1.5 mm. If the depth of the groove on the side of the end of the dressless exceeds 1.5 mm, there is a concern that the rigidity of the groove is lowered and the durability of the tire is lowered. Further, when the slip angle is increased and the pneumatic tire is grounded to the end of the paddle in the tread portion, if the depth of the groove on the end of the paddle is less than 1.0 mm, There is a concern that the role of the edge collapses due to the deformation of the ground plane, and the role of the edge is reduced.

  Moreover, the groove part in the pneumatic tire which concerns on the characteristic of this invention may be arrange | positioned at step shape.

  According to this invention, since the groove portion is stepped, rigidity in the tire circumferential direction is increased, and the role of the edge can be improved more effectively.

  ADVANTAGE OF THE INVENTION According to this invention, while ensuring driving performance, such as acceleration performance on a snowy road and straight running performance, the pneumatic tire which improves steering stability performance, especially cornering performance can be provided.

  Next, a pneumatic tire according to an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Composition of pneumatic tire)
FIG. 1 is a partially exploded perspective view of a pneumatic tire 1 according to this embodiment. As shown in FIG. 1, the pneumatic tire 1 has a pair of bead portions 11 including a bead core 11a and a bead filler 11b. Specifically, a steel cord or the like is used for the bead core 11a constituting the bead portion 11.

  The pneumatic tire 1 has a carcass layer 12 that is a skeleton of the pneumatic tire 1. On the outer side of the carcass layer 12 in the tire radial direction, a first belt layer 13 and a second belt layer 14 are disposed so as to overlap each other.

  A tread portion 15 in contact with the road surface is disposed on the outer side in the tire radial direction of the first belt layer 13 and the second belt layer 14. In addition, a groove portion 17 having a plurality of grooves in the tire circumferential direction is disposed in the padless portion 16 described later.

  Next, the tread portion 15 and the groove portion 17 of the pneumatic tire 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is a tread development view of the pneumatic tire 1 according to the present embodiment.

  As shown in FIG. 2, the pneumatic tire 1 includes a main groove 18 formed in the tire circumferential direction in the tread portion 15 and a sub groove 19 formed in the tread width direction. In addition, a plurality of groove portions 17 are arranged in the padless portion 16.

  Here, the padless portion 16 has both ends of the endless portion 16a that is the center position from the ground contact end portion 15a of the tread portion 15 to the maximum width portion. Moreover, the padless part 16 is good also considering the tire maximum width part 16b (not shown in FIG. 2, refer FIG. 1) used as the tire maximum width from the grounding edge part 15a of the tread part 15 as both ends.

  Next, with reference to FIG. 3, the above-described padless portion 16 will be described. FIG. 3 is a partial cross-sectional view in the tread width direction.

  As shown in FIG. 3, a groove portion 17 having a plurality of grooves formed in a step shape is formed in the padless portion 16. The depth of the groove portion 17 (hereinafter referred to as groove depth D1) is 0.5 mm to 1.5 mm, and the width of the groove portion 17 (hereinafter referred to as groove width W1) is 0.5 mm to 1.5 mm. Further, the groove depth D1 may be formed so as to increase stepwise from the ground contact end portion 15a to the padless end portion 16a. In this case, the grounding end side groove depth D1 is 0.5 mm to 1.0 mm, and the padless end side groove depth D2 is 1.0 mm to 1.5 mm.

  In addition, although the groove part 17 was demonstrated as what was comprised in step shape, it is not limited to this, Other shapes may be sufficient. For example, as shown in FIG. 4, the padless portion 16 is provided with a groove portion 17 that is rounded in a stepped shape (the shape shown in FIG. 3).

  In addition, as shown in FIG. 5, a groove portion 17 composed of a plurality of grooves is disposed in the tireless portion 16 in the tire circumferential direction. Furthermore, the groove part 17 comprised by several protrusion in the tire circumferential direction may be arrange | positioned at the padless part 16. As shown in FIG.

  In addition, in this embodiment, although the groove part 17 is comprised by the some groove | channel, you may be comprised by the at least 1 groove | channel.

(Operation and effect of the pneumatic tire according to the present embodiment)
According to the pneumatic tire according to the present embodiment, the groove portion 17 having at least one groove in the tire circumferential direction is provided in the paddle portion 16 located from the ground contact end portion 15a in contact with the road surface in the tread portion to the paddle end portion 16a. As a result, the lateral grip performance can be enhanced, so that the steering stability performance, particularly cornering performance can be exhibited. Further, the grip in the tire circumferential direction can be held without forming a sipe in the tire circumferential direction at the contact portion in the tread portion. In other words, acceleration performance and straight running performance can be ensured, and steering stability performance, particularly cornering performance can be exhibited.

  Further, since the depth of the groove portion 17 (hereinafter referred to as the groove depth D1) in the cross section in the tread width direction in the padless portion 16 is 0.5 mm to 1.5 mm, the rigidity is increased, so that the durability of the tire is further improved. In addition, since it can act as an edge, the grip performance in the lateral direction can be improved.

  Moreover, since the rigidity of the groove portion 17 in the tread width direction cross section (hereinafter referred to as the groove width W1) in the tread width direction section is 0.5 mm to 1.5 mm, the rigidity is increased, and thus the durability of the tire is further improved. Since it can play the role of an edge, the grip performance in the lateral direction can be improved.

 Further, when the pneumatic tire comes into contact with the road surface up to the dressless end portion 16a when the slip angle increases, the groove depth D1 is grounded by gradually increasing from the grounding end portion 15a to the padless end portion 16a. Since the role of the edge can be increased even with deformation at the time, the grip performance can be further improved.

 Further, since the groove depth D1 on the grounding end side is 0.5 mm to 1.0 mm, both durability improvement and edge role improvement can be achieved. If the groove depth D1 on the ground contact end side exceeds 1.0 mm, the rigidity of the ground contact end is lowered, and there is a concern that the durability of the tire may be reduced, such as a crack occurring in the bottom of the groove on the ground contact end. The Further, if the groove depth D1 on the ground contact end side is less than 0.5 mm, there is a concern that the role of the edge is lowered.

 Further, the groove depth D2 on the side of the end of the dressless is 1.0 mm to 1.5 mm, so that both the durability improvement and the edge role improvement can be achieved. If the groove depth D2 on the side of the end of the dressless exceeds 1.5 mm, there is a concern that the rigidity of the groove portion is lowered and the durability of the tire is lowered. Further, when the slip angle is increased and the pneumatic tire comes into contact with the road surface up to the paddle end portion 16a, if the groove depth D2 on the paddle end portion side is less than 1.0 mm, the contact surface on the paddle end portion 16a side There is a concern that the role of crushing edges may be reduced due to deformation.

  Further, the padless portion 16 has a staircase shape in the cross section in the tread width direction, thereby increasing the rigidity in the tire circumferential direction and improving the role of the edge more effectively.

  Examples of the pneumatic tire of the present invention will be described. In order to confirm the effect of the present invention, the tire of the example to which the present invention was applied and the tire of the comparative example were mounted on the rim, and in the test course of the snowy road surface, the straightness / responsiveness test, the grip performance test, the sliding behavior Tests and balance tests were conducted.

  In both the examples and comparative examples, the tire size is 205 / 55R16, and the carcass layer is polyester. The rim size was 16X6.5J, the internal pressure was 230 kPa front and 220 kPa corresponding to the maximum load capacity, and the load was equivalent to two passengers corresponding to the maximum load capacity. These figures are based on the 2004 JATMA and ETRTO standards. A 2000 cc class sedan type was used as an evaluation vehicle.

  The pneumatic tire of the example has a tread portion 15 shown in FIG. Further, the pneumatic tire of the comparative example includes, in the tread portion, a plurality of blocks partitioned by a plurality of main grooves formed in the tire circumferential direction and a plurality of sub grooves formed in the tread width direction. The sipe formed in the tire circumferential direction has a tread. In the pneumatic tire of the example, the groove width W1 is 1.0 mm at the paddle portion 16, the groove depth D1 is 0.5 mm on the ground contact end portion 15a side, and the groove depth D2 is 1.5 mm on the paddle end portion 16a side. It has the groove part 17 which becomes. In this case, the groove part 17 becomes deeper in steps from the grounding end part 15a to the padless end part 16a, and is configured in a stepped shape as shown in FIG.

<Straightness / responsiveness test>
Sensory evaluation was performed by a professional driver on straight speed and responsiveness (so-called steering feeling) when moving from a constant speed to the next lane (one lane) by running at a constant speed of 50 km / h in a straight section. The test was evaluated in five stages shown in Table 2 and represented as 3 as a reference, and the larger the value, the better the straightness / responsiveness. Here, the responsiveness includes a so-called steering feeling and a feeling of fit in the shifted lane.

<Grip performance test>
The circuit consisting of 4.41km per lap was made 10 laps, and the fastest lap time was measured. In the test, the reciprocal of the measured time was evaluated in five stages shown in Table 2, the tire of the comparative example was represented as 3, and the larger the value, the better the grip performance.

<Sliding behavior test>
The driver evaluated the slip behavior during turning. The test was evaluated in five stages shown in Table 2, and represented as 3 on the basis of a comparative example. The larger the value, the better the sliding behavior.

<Balance test>
Sensory evaluation was performed by the driver for the balance during turning using tires with an internal pressure of 230 kPa and a rear of 220 kPa. The test was evaluated in five stages shown in Table 2, and represented as 3 on the basis of a comparative example. The larger the value, the better the sliding behavior.

(result)
The evaluation results of Examples and Comparative Examples are shown in Table 1. As shown in Table 1, the examples have higher straightness and responsiveness than the comparative examples.

 Similarly, the grip is high and the steering stability during cornering is excellent. High speed of sliding behavior and excellent convergence when turning the handle during cornering. In addition, the balance is excellent, and the steering stability during cornering is excellent. As described above, the cornering performance of the example is higher than that of the comparative example. Therefore, it was found that by providing the groove portion 17 having the groove along the tire circumferential direction in the padless portion 16, while ensuring driving performance such as acceleration performance and straight running performance, steering stability performance, particularly cornering performance is improved. .

1 is a partially exploded tilt view of a pneumatic tire 1 according to an embodiment of the present invention. 1 is a development view of a tread of a pneumatic tire 1 according to an embodiment of the present invention. It is a tire direction sectional view of a slot concerning an embodiment of the present invention. It is a tire direction sectional view of a slot concerning an embodiment of the present invention. It is a tire direction sectional view of a slot concerning an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire 11 ... Bead part 11a ... Bead core 11b ... Bead filler 12 ... Carcass layer 13 ... 1st belt layer 14 ... 2nd belt layer 15 ... Tread part 15a ... Grounding edge part 16 ... Badress part 16a ... Badress edge part 16b ... Tire maximum width portion 17 ... Groove portion 18 ... Circumferential main groove 19 ... Width direction sub-groove

Claims (6)

  At least one groove along the tire circumferential direction has a contactless end portion in contact with the road surface in the tread portion, and a paddle portion having both ends of the contactless end portion that is a central position from the vicinity of the contacted end portion to the tire maximum width portion. A pneumatic tire comprising a groove portion having the following.  2. The pneumatic tire according to claim 1, wherein the groove has a groove depth that is a depth in a tire radial direction, and the groove depth is 0.5 mm to 1.5 mm.  The pneumatic tire according to claim 1, wherein the groove has a groove width that is a width in a tread width direction, and the groove width is 0.5 mm to 1.5 mm.  The pneumatic groove according to any one of claims 1 to 3, wherein the plurality of grooves constituting the groove part gradually increase in the groove depth from the vicinity of the grounding end part to the badless end part. tire.  The groove has a groove depth which is a depth in a tire radial direction, and the groove depth is 0.5 mm to 1.0 mm on the ground contact end side and 1.0 mm to 1 on the badless end side. The pneumatic tire according to any one of claims 1 to 4, wherein the pneumatic tire is 0.5 mm. The pneumatic tire according to claim 1, wherein the groove portion has a step shape in a cross section in the tread width direction.

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