JP2005225305A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire with excellent bad road running performance and side cut-resistance performance. <P>SOLUTION: A protector 5 projecting from a tire outer wall is arranged at an upper area of a side wall part and a sipe 6 comprising three-dimensional structure is formed on the protector 5. Further, if necessary, the sipe 6 comprising the three-dimensional structure is formed on an area from a tread ground-contact end of a block 4 formed on the outermost side in a width direction of a tread surface 1 to a buttress part side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire excellent in rough road running performance and side cut resistance suitable for off-road use.

  On the tread surface of off-road pneumatic tires that travel on rough roads such as muddy areas and mountainous areas, a block pattern with a larger tread groove area is adopted to ensure traction performance. In this type of tire, there is a tire that aims to improve side traction performance and rough road running performance by providing a protrusion in the upper region of the sidewall portion and providing a sipe in the protrusion (for example, Patent Documents 1 and 2).

In recent years, radial tires have been developed as this type of tire, and in the case of radial tires, it is necessary to make the shape of the block extending from the tread contact end to the sidewall portion side relatively small due to structural limitations. However, if the block extending from the tread grounding end to the side wall is small in this way, even if the tire is provided with a protrusion as described above, sufficient side traction in a muddy area cannot be obtained. There was a problem of being susceptible to side cuts due to contact and collision with rocks in the area.
Japanese Patent Laid-Open No. 7-26917 Japanese Patent Laid-Open No. 5-319022

  An object of the present invention is to solve the conventional problems and provide a pneumatic tire excellent in rough road running performance and side cut resistance.

  In order to achieve the above object, a pneumatic tire according to the present invention is a pneumatic tire in which a number of blocks are formed on a tread surface, and a protector protruding from a tire outer wall is disposed in an upper region of a sidewall portion. A sipe composed of at least one three-dimensional structure is formed.

  In the pneumatic tire according to the present invention, in a tire having a block pattern, a sipe having a three-dimensional structure is formed on the protector formed in the upper region of the sidewall portion, so that the rigidity of the side portion is appropriately maintained and the muddy ground is run. It is possible to improve the side traction performance at the time, the steering stability when traveling on rough roads, and the side cut resistance.

  Furthermore, by forming a sipe consisting of a three-dimensional structure in the area from the tread grounding edge of the block formed on the tread surface to the side of the sidewall, the side rigidity of the shoulder block is moderated and the wandering performance is improved. As a result, the maneuverability on rough roads can be further stabilized.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  1 is a front view showing an example of a pneumatic tire according to an embodiment of the present invention, FIG. 2 is a partial side view of the vicinity of a shoulder portion of the pneumatic tire of the present invention, and FIG. 3 is an XX in FIG. It is arrow sectional drawing.

  In FIG. 1, a tread surface 1 of a pneumatic tire has a large number of blocks 4 by a main groove 2 extending in the tire circumferential direction and a plurality of lug grooves 3 extending across the tread surface 1 and extending to the tread grounding end side. Forming.

  A protector 5 that protrudes from the outer wall of the tire is formed in the upper region of the sidewall portion of the pneumatic tire as shown in FIGS. As shown in FIG. 3, the protector 5 includes blocks 5 a arranged at intervals with respect to the tire circumferential direction, and each block 5 a is connected to three ridges 5 c extending in the circumferential direction. In each block 5a, at least one (four in the figure) sipe (hereinafter referred to as a three-dimensional sipe) 6 having a three-dimensional structure is formed in the tire radial direction. In the present invention, the upper region of the sidewall portion refers to a region on the tread portion side from the tire maximum width position of the sidewall portion.

  The above-described three-dimensional sipe 6 is formed such that both walls are formed into curved surfaces having different inclination angles in two or more directions in the sipe depth direction, and both the wall surfaces of the sipe are interspersed with concave portions and convex portions. Yes. Thereby, the block 5a in which the three-dimensional sipe 6 is formed has higher rigidity than the block in which the sipe extending linearly in the depth direction is formed.

  Therefore, by forming the three-dimensional sipe 6 in the block 5a, the rigidity of the protector 5 is appropriately maintained, and the side traction performance during muddy road driving, the steering stability during rough road driving, and the side cut resistance are improved. be able to.

  Each block 5a constituting the protector 5 may be independently arranged at a predetermined interval with respect to the tire circumferential direction without being connected to the convex shape 5c.

  The protrusion height h from the tire wall surface of the protector 5 is preferably 2 to 6 mm from the viewpoint of maintaining the side traction performance and the side cut resistance. The three-dimensional sipe 6 formed on the protector 5 maintains the side traction performance and the side cut resistance, and at the same time, reduces the impact from surrounding obstacles and improves the handling stability. ) Is 0.4 to 1 mm, and the depth is preferably 2 mm or more.

  The size and number of the protectors 5 are determined each time according to the tire size and the like. Further, the direction of the three-dimensional sipe 6 formed on the protector 5 is not particularly limited, and may be a tire radial direction as shown in FIG. 2 or a tire circumferential direction.

  4 is a partial side view corresponding to FIG. 2 in the vicinity of a shoulder portion of a pneumatic tire according to another embodiment of the present invention, and FIG. 5 is a cross-sectional view corresponding to FIG. 3 of the tire of FIG.

  In this embodiment, the protector 5 is arrange | positioned in parallel with the tire circumferential direction by the 1 or several (2 figure) rib 5b which protrudes 2-6 mm from a tire wall surface. Each rib 5b is preferably formed with a three-dimensional sipe (not shown). The direction of the three-dimensional sipe is not particularly limited, but it may be formed in the radial direction on the inner peripheral side where the outermost block 4 is located in order to equalize the side rigidity. Each rib 5b may be a rib that is divided in the tire circumferential direction.

  In this way, the protector 5 is constituted by one or a plurality of ribs 5b, and the three-dimensional sipe 6 is formed on the ribs 5b, so that the rigidity of the protector 5 is appropriately increased as in the embodiment shown in FIGS. It is possible to maintain and improve the side traction performance during muddy road driving, the steering stability during rough road driving, and the side cut resistance.

  In the present invention, the protector 5 described above may be a combination of the block 5a and the rib 5b as appropriate.

  FIG. 6 is a partial side view corresponding to FIG. 2 in the vicinity of a shoulder portion of a pneumatic tire according to still another embodiment of the present invention.

  In the present embodiment, in addition to the configuration according to the above-described embodiment, at least one (three in the figure) is provided in the region extending from the tread grounding end of the block 4 formed on the outermost side in the width direction of the tread surface 1 to the side of the sidewall. The three-dimensional sipe 6 is formed in the tire circumferential direction. Even in this embodiment, the direction of the three-dimensional sipe 6 formed in the block 4 may be the tire radial direction. In addition, although FIG. 6 illustrates the case of combining with the embodiment of FIG. 2, it is not limited to this.

  By forming the three-dimensional sipe 6 in the region from the tread grounding edge to the side wall portion in this way, the side rigidity of the shoulder block is moderated moderately to enhance the wandering performance, thereby improving the maneuverability on rough roads. It can be further stabilized.

  As described above, in the pneumatic tire of the present invention, a protector made of blocks and / or ribs protruding from the outer wall of the tire is disposed in the upper region of the sidewall portion, and a sipe having a three-dimensional structure is formed on the protector. Therefore, the rigidity of the protector 5 is moderately maintained, and the side traction performance at the time of muddy road driving, the steering stability at the time of rough road driving, and the side cut resistance performance are improved. The groove area ratio of the tread surface is 40-60. % Is preferably applied to off-road tires.

  With the tire size (LT265 / 70R17) and the tread pattern (Fig. 1) in common, 40 protectors consisting of blocks with a height of 4 mm and a size of 40 mm x 30 mm are arranged on the tire circumference in the upper region of the sidewall part, Conventional tires that do not form sipes in each block (conventional example), comparative tires that form two two-dimensional sipes in the circumferential direction (comparative example), and tires of the present invention that form two three-dimensional sipes in the circumferential direction ( Example) was produced respectively.

The above three types of tires are mounted on a 3.2 liter 4WD gasoline vehicle off-road SUV vehicle, and the mountainous rocky course (total length of about 10km) is made to lap for 10 laps, and the average running time per lap is measured. At the same time, the steering stability and side-quad resistance were evaluated by the following methods, and the results are shown in Table 1 using an index with the conventional example being 100. The larger the value, the better.

[Maneuvering stability evaluation method]
Evaluation was made based on the sensory evaluation results of the driver.
[Side-cut resistance evaluation method]
The cut occurrence state (number, size and depth) in the side portion of the tire after running was examined and evaluated based on the results.

表１より、実施例は、従来例に比して、悪路走破性能（走行時間、操縦安定性）及び耐サイドカット性能に優れていることがわかる。

From Table 1, it can be seen that the example is superior in rough road running performance (running time, steering stability) and side-cut-proof performance as compared with the conventional example.

1 is a front view showing an example of a pneumatic tire according to an embodiment of the present invention. It is a partial side view near the shoulder part of the pneumatic tire of the present invention. It is XX arrow sectional drawing of FIG. It is a side view equivalent to FIG. 2 of the pneumatic tire by other embodiment of this invention. FIG. 5 is a cross-sectional view corresponding to FIG. 3 of the pneumatic tire of FIG. 4. FIG. 6 is a side view corresponding to FIG. 2 of a pneumatic tire according to still another embodiment of the present invention.

Explanation of symbols

1 tread surface 2 main groove 3 lug groove 4 block 5 protector 5a block 5b rib 6 3D sipe

Claims (6)

In a pneumatic tire in which a large number of blocks are formed on the tread surface, and a protector that protrudes from the outer wall of the tire is disposed above the sidewall portion.
A pneumatic tire in which a sipe having at least one three-dimensional structure is formed on the protector.   The pneumatic tire according to claim 1, wherein the height of the protector protruding from the tire wall surface is 2 to 6 mm.   The pneumatic tire according to claim 1 or 2, wherein a gap between sipes composed of the three-dimensional structure is 0.4 to 1 mm and a depth is 2 mm or more.   The pneumatic tire according to claim 1, 2 or 3, wherein the protector is a block and / or a rib arranged in the tire circumferential direction.   The air according to any one of claims 1 to 4, wherein a sipe having at least one three-dimensional structure is formed in a region from a tread grounding end of the block formed on the outermost side in the width direction of the tread surface to a side wall portion. Enter tire. The pneumatic tire according to any one of claims 1 to 5, wherein a groove area ratio of the tread surface is 40 to 60%.

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