JPH09132010A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent a stone bite without deteriorating the durability and the wet performance by providing notches on the other groove side wall in the place where the one groove side wall is connected to lateral groove in a pair of lateral groove side walls forming grooves in the peripheral direction. SOLUTION: Four peripheral direction grooves 1, 2 are provided on a tread of a pneumatic tire, furthermore, a lot of lateral grooves 3, 4, and 5 are provided with spaces on a periphery of the tread. A lot of blocks 10, 11, and 12 are formed with spaces on the periphery of the tread by those peripheral direction grooves 1, 2 and the lateral grooves 3, 4, and 5. Then, notches 6, 7, 8, and 9 are provided on the groove side walls of the periphery direction grooves 1, 2 in a place where the lateral grooves 3, 4, and 5 are connected to the peripheral direction grooves 1, 2, that is, in a place where a stone bite may occur because ends of blocks are centered to cause the rigidity around to be lowered. Thereby, to bite a stone is restrained and also the wet performance is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tread pattern of a heavy duty pneumatic tire, and more particularly to prevention of stone bites.

[0002]

2. Description of the Related Art Heavy-duty pneumatic tires, especially tires traveling on bad roads, bite stones in a groove to damage the tires or once the bitten stones come off during traveling to cause damage to surrounding vehicles. It was dangerous. Conventionally,
In order to improve the biting property of the stone, it is necessary to make a large angle of the groove side wall with respect to the normal line to the tread surface in a cross section perpendicular to the direction in which the groove extends, or to install a so-called stone ejector in the groove. Was generally done.

[0003]

However, if the angle of the side wall of the groove is simply increased as described above, the R of the groove bottom becomes small, so that the rubber cracks from the groove bottom due to the deterioration of the rubber due to running. No improvement has been made to the problem that it occurs and the problem that it is easy to bite stones at the place where the circumferential main groove and the lateral groove are connected. In addition, it is the current situation that the stone ejector cannot solve the problem of reducing the wet performance of the tire.

Therefore, an object of the present invention is to propose a pneumatic tire in which stone bites are effectively prevented without lowering durability and wet performance.

[0005]

In order to achieve the above object, the pneumatic tire of the present invention has at least two circumferential grooves, is connected to the circumferential grooves, and is arranged at intervals in the circumferential direction. In a pneumatic tire having a tread with a large number of lateral grooves, of a pair of left and right groove sidewalls forming a circumferential groove, one groove sidewall is connected to the lateral groove, and a notch is formed in the other groove sidewall. Is forming.

Further, if the side wall angle of the notch is larger than the angle of the groove side wall in the circumferential direction with respect to the normal to the tread surface in the cross section perpendicular to the direction in which the circumferential groove extends, stone biting is further reduced, which is preferable. .

In a pneumatic tire having two circumferential main grooves and a large number of lateral grooves that are connected to the circumferential main groove and are arranged at intervals in the circumferential direction, stone biting is the most problematic problem. This is where the lateral groove connects to the circumferential groove.
It becomes the S section. This part is where the block ends gather, and the rigidity of the surrounding area is reduced, which makes it easier for stones to bite. In this case, if the notch is formed in the groove side wall of the circumferential groove at the location where the lateral groove is connected to the circumferential groove as in the configuration adopted by the present invention, the space in this portion becomes large and stone biting occurs. It becomes difficult. Furthermore, if the side wall angle of the notch is made larger than the angle of the groove side wall of the circumferential groove with respect to the normal to the tread surface in the cross section perpendicular to the direction in which the circumferential groove extends, stones are less likely to bite in the notch and the improvement effect Is big. Further, the wet performance is also improved by providing the cutout portion.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a partially enlarged front view of a tread pattern of a pneumatic tire for trucks and buses according to an embodiment of the present invention. , Tire size is 10.0
0R20. As shown in the drawing, the tread of the pneumatic tire of the embodiment is provided with four circumferential grooves 1, 2.
Furthermore, it is provided with a number of lateral grooves 3, 4, 5 arranged at intervals on the circumference, and by these circumferential grooves 1, 2 and lateral grooves 3, 4, 5 a large number of blocks 10, 11 are provided. ,
12 are formed at intervals on the circumference of the tread. Further, it is characterized in that notches 6, 7, 8 and 9 are provided on the groove side wall of the circumferential groove at the location where the lateral groove is connected to the circumferential groove.

In order to confirm the effect of the present invention, a tire having notches 6, 7 and 8 was manufactured based on the specifications shown in Table 1. As a comparison, a tire having no notch shown in FIG. 3 was manufactured as a prototype with the same structure except for the notch. These tires were loaded on a 7.50V rim with an internal pressure of 9.0.
It is mounted on the rear of a 10-ton dump truck with a kg / cm ² assembly, and runs at a speed of 40-60 km / h for 5,000 km on a stoney site, where the lateral groove within one tire connects to the circumferential groove. Table 1 also compares the number of stones at each location.
It is shown in

[0010]

[Table 1]

As is clear from the above, the tire of Example 1 provided with the notch has a significantly improved stone biting compared to the comparative example, and Example 2 in which the side wall angle of the notch is further increased
No stone bites were seen in.

[0012]

As is clear from the above description, according to the present invention, it is possible to significantly reduce the stone biting of the pneumatic tire.

[Brief description of the drawings]

FIG. 1 is a partially enlarged front view of a tread pattern of a pneumatic tire according to the present invention.

FIG. 2 is a groove cross-sectional view of the pneumatic tire in FIG.

FIG. 3 is a partially enlarged front view of a tread pattern of a conventional pneumatic tire having no notch.

[Explanation of symbols]

 1, 2 circumferential groove 3, 4, 5 lateral groove 6, 7, 8, 9 notch 10, 11, 12 block N tread normal E tire equatorial line (tread pattern center)

Claims (2)

[Claims] 1. A pneumatic tire comprising a tread having at least two circumferential grooves and a plurality of lateral grooves connected to the circumferential grooves and arranged at intervals in the circumferential direction,
A pneumatic tire characterized in that, of a pair of left and right groove side walls forming the circumferential groove, a notch is formed in the other groove side wall at a position where one groove side wall is connected to the lateral groove. 2. The sidewall angle of the notch is larger than the angle of the circumferential groove sidewall with respect to a normal line to the tread surface in a cross section perpendicular to the direction in which the circumferential groove extends. 1. The pneumatic tire according to 1.