JPS61218406A - Heavy load pneumatic tire capable of making run-flat - Google Patents

Abstract

PURPOSE:To provide snow performance of the above-captioned tire, especially, the same performance of a snow tire as of a general tire, by setting within a specific range an angle of an inner wall of main grooves forming a block pattern on a tread surface. CONSTITUTION:The above-captioned tire is provided with a carcass layer 2 and a rubber layer 3 for reinforcing a side wall area 5 at the inner circumferential portion of the tire. A tread portion is formed with main grooves extending in the circumferential direction of the tire and main grooves extending in the lateral direction of the tire. An angle alpha of an inner wall of the main grooves forming the block pattern is set to 10-25 deg., preferably 13-12 deg.. If the angle is less than 10 deg., snow filled in the main grooves cannot be expelled, causing reduction in a tractive force, brake performance and maneuvarability on the snow. If the angle is more than 25 deg., the snow is not filled in the main grooves, but rigidity of each block is increased to reduce a snow pressing effect, resulting in reduction in snow performance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the shape of main grooves that define the tread surface pattern of a heavy-duty pneumatic bias snow tire capable of run-flat running.

(Prior art) Snow tires generally have a main groove extending in the circumferential direction and a main groove extending in the transverse direction to divide the tread surface into relatively small blocks, which are effective for traction on snow. Large amount of abrasion poliium.

As a means of achieving this objective, the main groove is formed into a relatively U-shaped shape, that is, the groove wall angle (angle with respect to the normal to the tire tread outer ring) is made small, generally in the range of 00 to 5 degrees.

On the other hand, special tires such as run-flat tires are currently in demand, and this type of heavy-load pneumatic bias tire is no exception. The thick rubber layer is placed near the other beads in a shape that further strengthens the sidewall area in particular.

Naturally, these run-flat tires are required to have improved snow performance, and the shape of the tread and main groove is also U-shaped, that is, the groove wall angle is small, generally in the range of 0° to 5°. be.

(Problems to be Solved by the Invention) However, in general snow tires, the rigidity of the carcass layer is relatively low even when filled with the normal internal pressure for use. In other words, the tread surface part moves easily during load transfer, and even if snow etc. enters the main groove, it is easily pushed out, and there are no problems with brake performance, traction force, or steering stability, but run flat running is possible. The inner surface of the tire, especially the sidewall area, is reinforced to allow load transfer even when the working internal pressure is O, in other words, it is possible to run flat I, so when used with the tire filled to the normal working internal pressure. , the movement during load transfer, that is, the deflection, is extremely small compared to the general tires. For example, when looking at the amount of deflection of a tire, it is only 1/2 to 1/3 of a regular tire. As a result, even if snow etc. enters the main groove of the I/Red road surface, it becomes impossible to push out the snow due to the movement of the tread during load transfer, resulting in an extremely low traction force, braking performance, and steering stability performance. Then, regarding pneumatic bias tires, especially snow tires, 1.
It provides a main groove shape that enables snow-1 = performance similar to general tires with no / σ).

(Means for Solving the Problems) As a result of various research and studies conducted by the inventors, this type of special tire is used only for special vehicles, unlike general tires for passenger cars and tires for trucks and buses.

However, compared to conventional snow tires, it was found that the effective wear volume was not as much of an issue as on the left, and run-flat driving performance and on-snow performance were the most important.

As a result of further investigation, it was found that how easily and quickly the snow gets stuck on the snow and how quickly it can be pushed out depends on the groove wall angle of the main groove that partitions the blocks. Therefore, it has been found that the present invention can specifically be achieved by the following configuration.

The present invention provides a carcass bra which extends from one of the bead parts in which a pair of left and right bead wires are embedded, passes through one side part, the crown part, and the other side part to the other bead part, and is fixed to each bead wire there. On the inner surface, the sidewall area is reinforced with a rubber layer from near one bead to near the other bead, and the tread road surface is blocked by main grooves extending in the tire circumferential direction and main grooves extending in the transverse direction. It consists of a pattern,
A pneumatic bias tire for heavy loads capable of run-flat running, characterized in that the groove wall angle of the main groove that partitions the blocks is 10' to 25 degrees. <It's an ear tire.

(Function) In the present invention, the groove wall angle of the main grooves that partition the blocks is limited to the range of io' to 25°, preferably 13° to 20°, because snow stuck in the main grooves is It becomes impossible to push out during load transfer, resulting in reduced traction, braking performance, and steering stability on snow. If the angle is 25° or more, the snow will get stuck in the main groove and the snow performance will deteriorate.

゛(Example) The present invention will be explained in detail according to examples.

The tire of the present invention has a size 14.00-20 and is
The figure is a schematic sectional view showing an embodiment of the present invention. Two player layers 1 are arranged alternately at 400 degrees in the circumferential direction of the tire. 100 carcass layers 2 are alternately arranged at 40 degrees to the tire circumferential direction. The material of the breaker layer 1 is 840 d/2 nylon, and the material of the carcass layer 2 is 1890 d/2 nylon. Reference numeral 3 denotes a rubber layer reinforcing the inner surface to enable run-flat running. The rubber layer 3 is disposed on the entire inner surface of the tire, but it is preferable to further strengthen the sidewall area 5. Particularly preferably, the thickness S of the carcass layer maximum width area of the rubber layer 3
O needs to be 5 to 14% of the carcass layer maximum width SW.

FIG. 2 is a cross-sectional view of the main groove of the tire of the present invention, and the experimental results of the run-flat performance and on-snow performance of the tire of the present invention and the conventional tire are explained in the table below.

As explained above in Section 1 and Section 1 above, the present invention provides a tire that satisfies runflat performance at the same time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the tire of the present invention. FIG. 2 is a longitudinal sectional view of the main groove tire of the present invention. Figure 1 Figure 2

Claims (1)

[Claims] 1. From one of the bead parts in which a pair of left and right bead wires are embedded, pass through one side part, the crown part, and the other side part to the other bead part, and there, the carcass ply is fixed to each bead wire, and the carcass ply A tread rubber layer is provided on the outside of the tire case body, which is provided with a breaker located at the crown portion on the outside as a layered reinforcement, and a tread rubber layer is provided on the inner surface of the tire from the vicinity of one bead to the vicinity of the other bead. A heavy-duty pneumatic bias tire capable of run-flat running, with the wall area reinforced with a rubber layer and a block pattern formed by main grooves extending in the tire circumferential direction and main grooves extending in the transverse direction on the tread surface. A heavy-load pneumatic bias tire capable of run-flat running, characterized in that the groove wall angle of the main groove that partitions the blocks is 10° to 25°.