JPH03197208A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To improve an edge effect and block rigidity by arranging an annular sheeting inside a block forming a tread pattern in such a way as not be continuous to a surrounding groove, and arranging another sheeting in the annular sheeting continuous thereto. CONSTITUTION:Two main grooves 6 are provided along a tire peripheral direction T between the central area of a tread and a shoulder area at both sides thereof. Also, lateral grooves 8 continuous to the main grooves 6 and a shoulder edge are formed along the widthwise direction of a tread. Furthermore, auxiliary grooves 10 are provided in the tread for continuity among the lateral grooves 8. In the aforesaid construction, an annular sheeting 12 as a closed sheeting is formed inside each block 1. Also, a plurality of sheetings 2 as open sheetings having both ends continuous to the annular sheeting 12 are provided therein. According to the aforesaid construction, many small blocks 4 are formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having sipes that have the advantages of both open sipes and closed sipes. It is.

[Prior Art] As is well known, studless tires without spikes have come to be widely used as winter tires due to the dust problem caused by spiked tires.

This studless tire generally has a tread made of flexible rubber formed in a block pattern, and is provided with a large number of sipes to improve the edge effect.

Conventional sipes are generally classified into open sipes and closed sipes. As illustrated in FIG. 3, an open sipe is a sipe 2 provided in a block 1, which is connected to a groove around the block 1 at both ends, and is divided into small blocks 4 that are independent from each other. be. This open size has the advantage of being able to exert an edge effect over the entire sipe, but has the disadvantage of reducing block rigidity.

A closed sipe is one in which both ends of the sipe 2 do not communicate with the outer groove and end within the block 1, as illustrated in FIG. Therefore, although it has the advantage that the block rigidity does not decrease, it has the disadvantage that the openings near both ends of the sipe 2 are insufficient during braking and driving, and the edge effect is not sufficiently exhibited.

As described above, the sipes provided in the conventional block pattern have advantages and disadvantages, and have been considered to be a limitation when attempting to further improve braking and driving performance.

(Problems to be Solved by the Invention) An object of the present invention is to provide a pneumatic tire that combines the advantages of closed sipes that do not reduce block rigidity and the advantages of open sipes that can fully utilize the edge effect of the sipes. It is in.

[Means for Solving the Problems] A pneumatic tire of the present invention for achieving the above-mentioned object has a tread pattern based on a block pattern, and includes blocks constituting the block pattern. It is characterized by forming an annular sipe that is not connected to the groove around the annular sipe, and providing within the annular sipe a small number of sipes (at least one end of which communicates with the annular sipe).

In a pneumatic tire with this structure, the sipes are not connected to the groove around the block, so the block rigidity is maintained like a conventional closed size, and the sipe is an open sipe whose end communicates with the annular sipe. Since it is made into a mold, the edge effect can be exerted over the entire sipe.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

The pneumatic tire shown in FIG.
Further, a lateral groove 8 is provided which communicates with the main groove 6 and the shoulder edge in the width direction of the tire. Also,
Narrow auxiliary grooves 10 communicating between the lateral grooves 8 are provided in the center of the tread and a part of the shoulder, and a large number of trapezoidal blocks 1 are provided in the center, and a large number of pentagonal blocks are provided in the shoulder part. A block l is formed.

An annular sipe 12 in which both ends of the sipe are connected to each other in a loop shape is provided inside each block 1, and a plurality of sipes 2 each having both ends connected to the annular sipe 12 are provided within this annular sipe 12. The sipes 2 mainly generate an edge effect for braking and driving performance of the tire, and are therefore provided in a direction transverse to the circumferential direction T of the tire as shown in the figure. Further, this sipe 2 may have its direction changed midway. Further, the blocks 1 arranged at the shoulder edge portion in FIG. 1 are formed in a shape such that the inner ends of the plurality of sipes 2 in the tire width direction communicate with the sipes 14 that divide the annular sipe 12 into two.

That is, the basic form of sipe formation according to the present invention is as shown in FIG. It is designed to form a small block 4. Therefore, the sipe 2, which has one end communicated with the annular sipe 12, can be opened over its entirety during braking and driving to exhibit a high edge effect. Moreover, since the periphery of the block l is not separated, the block rigidity does not decrease as in the case of a closed sipe.

Therefore, the pneumatic tire of the present invention shown in FIG. 1 can improve driving and braking performance on icy and snowy roads, as well as provide steering stability on dry roads.

The groove depth of the sipe 2 and the annular sipe 12 is preferably equal to or less than the groove depth of the main groove, lateral groove, etc. provided around the block. If the groove depth of the sipe exceeds the groove depth around the block, it not only reduces the block rigidity but also affects the inner tire casing.

〔Effect of the invention〕

As explained above, in the pneumatic tire of the present invention, an annular sipe is formed in a block, and a sipe communicating with the annular sipe at one end is provided in the annular sipe to form a small block. Therefore, it is possible to form a plotter pattern that has the respective advantages of open sipe and closed sipe, and eliminates the 4° disadvantage of both.

Therefore, the pneumatic tire of the present invention can improve driving and braking performance on icy and snowy road surfaces.

[Brief explanation of drawings]

FIG. 1 is a partially exploded view showing an example of the tread pattern of the pneumatic tire of the present invention, FIG. 2 is a block surface diagram showing the basic shape of the sipes provided in the pneumatic tire of the present invention, and FIG.
FIG. 4 is a block surface diagram showing the basic form of conventional sipe forming means. 1...Block, 2, 14...Sipe, 4...Small block, 12...Annular sipe.

Claims (1)

[Claims] It has a tread pattern based on a block pattern, and in the blocks constituting the block pattern, an annular sipe that is not connected to the groove around the block is formed, and at least one end is formed in the annular sipe. A pneumatic tire with a sipe that communicates with the annular sipe.