JP5506353B2 - Pneumatic tires for motorcycles - Google Patents

Description

  The present invention relates to a pneumatic tire for a motorcycle (hereinafter, also simply referred to as “tire”), and more particularly to a pneumatic tire for a motorcycle according to an improvement in a tread pattern.

  Conventionally, in a tread pattern of a pneumatic tire for motorcycles, in order to improve grip and contact feeling on a wet road surface, a sub-groove arranged substantially perpendicularly to the main groove arranged in the tire circumferential direction is used. Linking has been done. In addition, in order to suppress a decrease in rigidity of the tire tread surface caused by connecting the main grooves with sub grooves, the overall groove amount (negative rate) is reduced, while sacrificing wet grip and grounding. A technique to ensure a feeling is also used.

  As a technique for improving the grip performance on a wet road surface, for example, Patent Document 1 discloses a rotation direction designation tread pattern in which a large number of inclined main grooves are arranged in a square shape on both sides of a tread surface. A pneumatic tire for a motorcycle according to an improvement is disclosed. In this tread pattern, the inclined main groove has two branch grooves branched from the main groove. Further, Patent Document 2 discloses a pneumatic tire for a motorcycle in which a tread portion is formed with a pattern having a main groove that continuously crosses at least one of the ground contact ends when traveling straight and does not communicate in the circumferential direction. Is disclosed. Also in this tread pattern, one branch groove branched from the main groove is arranged.

Japanese Patent Laid-Open No. 11-208218 (Claims etc.) JP 2007-290538 A (Claims etc.)

  However, with the conventional tread pattern, it is difficult to achieve both a grip and a feeling of grounding while ensuring the rigidity of the tire tread portion, and the connecting portion of the groove is substantially perpendicular to the input direction during the inclined traveling. As a result, the corners of the grooves are turned up, and the appearance is very bad.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve a grip when driving on a wet road and to improve a feeling of touching when driving on a dry / wet road while suppressing a decrease in rigidity and appearance of a tire tread. It is to provide a pneumatic tire for use.

  As a result of intensive studies, the present inventor has provided a sub-groove that intersects the main groove in a T-shape in a specific region of the main groove in a tread pattern including the main groove that is inclined with respect to the tire circumferential direction. Thus, the inventors have found that the above problems can be solved, and have completed the present invention.

That is, the pneumatic tire for a motorcycle according to the present invention is for a motorcycle having a tread portion, a pair of sidewall portions that are continuous to both sides of the tread portion, and a pair of bead portions that are respectively continuous to the pair of sidewall portions. In pneumatic tires,
The tire tread has a tread pattern including a plurality of main grooves arranged to be inclined with respect to the tire circumferential direction, and a part of the main grooves is formed in the main grooves on the tread end side from the ground contact area during straight traveling. A sub-groove arranged substantially perpendicularly to the T-shape, the sub-grooves are periodically arranged in the tire circumferential direction, and a part of the main grooves having the sub-grooves, It extends to the tread end without communicating with other grooves.

  In the present invention, it is preferable that the sub-groove is disposed only in a range from the ground contact edge during straight traveling to a point of 1/4 + 1/16 of the tread width in the tire width direction from the tire center. Further, the main groove includes at least two types of main grooves having different inclination angles with respect to the tire circumferential direction, and the sub-groove is disposed in a main groove having a large inclination angle with respect to the tire circumferential direction among the main grooves. It is preferable. Furthermore, it is preferable that the main groove includes at least two types of main grooves having different inclination angles with respect to the tire circumferential direction, and of the main grooves, the main groove having a small inclination angle with respect to the tire circumferential direction terminates in the tread. . In addition, the tire tread has an auxiliary groove that is inclined with respect to the tire circumferential direction together with the main groove, and the positions of the main groove and the auxiliary groove in the tire circumferential direction are offset on both sides in the tire width direction. It is preferable that

  The tread patterns disclosed in Patent Documents 1 and 2 also have branch grooves that branch off from the inclined main grooves, but these branch grooves are all provided near the center of the tire that contacts the ground when traveling straight ahead. Yes. If the branch groove touches the road surface when traveling straight ahead, road noise and wear tend to deteriorate.Therefore, it is essential to place the sub-groove according to the present invention in a region that does not contact the road surface during straight traveling. It is a requirement.

  According to the present invention, with the above-described configuration, improvement in grip when driving on a wet road surface and improvement in feeling of grounding when traveling on a dry / wet road surface while suppressing a decrease in rigidity of the tire tread surface and deterioration in appearance. This makes it possible to realize a pneumatic tire for motorcycles.

1 is a partial development view of a tread portion showing a tread pattern of a pneumatic tire for a motorcycle according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partial development view of a tread portion showing a tread pattern of a pneumatic tire for a motorcycle according to the present invention. As shown in the drawing, the tire according to the present invention includes a directional tread pattern including a plurality of main grooves 1 and 2 arranged at an inclination with respect to the tire circumferential direction on the tire tread surface. The arrow in the figure indicates the direction of rotation of the tire.

  In the present invention, a part of the main groove, in the illustrated example, the main groove 1 has the sub-groove 3 on the tread end side from the ground contact region X during straight traveling. As shown in the figure, the sub-grooves 3 are arranged substantially perpendicular to the main groove 1 so as to intersect with each other in a T shape, and are periodically arranged in the tire circumferential direction. As described above, the secondary groove is provided at a specific position of the inclined main groove, so that the grip on the wet road surface can be maintained while maintaining the appropriate groove amount (negative rate) and ensuring the rigidity of the tread portion. It has become possible to provide a tire with improved safety during traveling by improving both the feeling of grounding when traveling on dry / wet roads. In addition, since the T-shaped sub-groove according to the present invention is shorter than the conventional connecting sub-groove, it is possible to suppress the turning-up phenomenon of the groove corner due to the input to the tire at the time of inclined traveling, as a result. Further, it is possible to obtain an effect of maintaining a good appearance of the tire tread until the end of traveling. Here, the sub-groove 3 is arranged substantially perpendicularly to the main groove 1. The main groove 1 is 1/4 + 1/16 of the tread width from the ground contact end E and the tire center C when traveling straight. It means that the angle of the minor groove 3 with respect to the tangent line between the points is in the range of 80 to 110 °.

  In the present invention, as long as the auxiliary groove 3 is disposed on the tread end side from the ground contact region X when traveling straight, the sub-groove 3 prevents the deterioration of road noise and wear as described above, and the intended purpose of the present invention. Although the effect can be obtained, it is preferably arranged in a range from the ground contact E during straight traveling to the point of 1/4 + 1/16 of the tread width from the tire center C. That is, the sub-groove 3 is arranged in a range from the ground contact E to a point outside the quarter of the tread width divided by 1/4 and 1/16 of the tread width. If the arrangement position of the sub-groove 3 is on the tread end side from this range, it is not possible to improve the grip on wet road surface and the feeling of touching on dry / wet road surface in the camber angle region that is frequently used during general traveling. Therefore, it is not preferable.

  Further, in the present invention, the main groove in which the sub-groove is arranged is not particularly limited, but preferably, as shown in the figure, as the main groove, at least two kinds of main grooves 1 having different inclination angles with respect to the tire circumferential direction are used. 2 and the sub-groove 3 is arranged in the main groove 1 having a large inclination angle with respect to the tire circumferential direction. By arranging the sub-groove 3 in the main groove 1 having a larger inclination angle than in the main groove 1 having a small inclination angle, the grip during wet road running and the feeling of ground contact during dry / wet road running are improved. The degree can be increased.

  Furthermore, in the present invention, as shown, at least two main grooves 1 and 2 having different inclination angles with respect to the tire circumferential direction are provided as main grooves, and of these, the main grooves with a small inclination angle with respect to the tire circumferential direction. About 2, it is preferable to make it terminate in a tread, without making it open to a tread end. As a result, it is possible to enhance the grip when traveling on a dry road surface in a large camber angle region and also ensure a wet grip necessary for general wet traveling.

  Furthermore, in the present invention, as shown in the figure, auxiliary grooves 4 and 5 that are inclined with respect to the tire circumferential direction are arranged on the tire tread surface together with the main grooves 1 and 2, and these main grooves 1 are arranged. , 2 and the auxiliary grooves 4 and 5 are preferably offset on both sides in the tire width direction. Thereby, the tread pattern rigidity in each camber angle region can be optimized, and a stable grip and a feeling of grounding can be realized.

  The arrangement pitch of the main grooves, particularly the main grooves and the auxiliary grooves in the present invention is not particularly limited, but can be, for example, about 1/50 to 1/40 of the entire circumference of the tire. When the position in the circumferential direction is offset, the circumferential offset amount can be set to about 1/4 to 1/2 of the entire circumferential length of the tire.

  In the tire of the present invention, only the point that satisfies the conditions related to the tread pattern is important, and thereby the desired effect of the present invention can be obtained, and other tire structures and materials of each member, etc. Details are not particularly limited. For example, although not shown, the tire of the present invention includes a tread portion, a pair of sidewall portions that are continuous on both sides of the tread portion, and a pair of bead portions that are respectively connected to the pair of sidewall portions. It has a carcass that is arranged between bead cores embedded in each part and reinforces each part, and a belt that is arranged on the outer periphery of this carcass and reinforces the tread part.

1, 2 Main groove 3 Sub groove 4, 5 Auxiliary groove

Claims (5)

In a pneumatic tire for a motorcycle having a tread portion, a pair of sidewall portions continuous on both sides of the tread portion, and a pair of bead portions respectively connected to the pair of sidewall portions,
The tire tread has a tread pattern including a plurality of main grooves arranged to be inclined with respect to the tire circumferential direction, and a part of the main grooves is formed in the main grooves on the tread end side from the ground contact area during straight traveling. have a minor groove disposed to cross the T-shape substantially perpendicularly against, the sub-grooves are periodically arranged in the tire circumferential direction, and is part of a main groove having a sub groove, A pneumatic tire for a motorcycle, characterized by extending to a tread end without communicating with another groove . 2. The pneumatic tire for a motorcycle according to claim 1, wherein the sub-groove is disposed only in a range from a ground contact edge at the time of straight traveling to a point of 1/4 + 1/16 of the tread width in the tire width direction from the tire central portion. .   The main groove includes at least two types of main grooves having different inclination angles with respect to the tire circumferential direction, and the sub-groove is disposed in a main groove having a large inclination angle with respect to the tire circumferential direction. A pneumatic tire for a motorcycle according to 1 or 2.   The main groove includes at least two kinds of main grooves having different inclination angles with respect to the tire circumferential direction, and the main groove having a small inclination angle with respect to the tire circumferential direction terminates in the tread. A pneumatic tire for a motorcycle according to any one of the above.   The tire tread has an auxiliary groove that is inclined with respect to the tire circumferential direction together with the main groove, and the positions of the main groove and the auxiliary groove in the tire circumferential direction are offset on both sides in the tire width direction. The pneumatic tire for a motorcycle according to any one of claims 1 to 4.

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