JPH02197402A - Tread structure of tire for automobile - Google Patents

Abstract

PURPOSE:To always secure good drain efficiency between the tread land portion and the road surface by a wide portion and to improve the braking performance by disposing sipes on the tread land portion in such a manner as to communicate with tread grooves and forming the sipes in such a manner as to continuously alternate with narrow portions and wide portions. CONSTITUTION:Plural tread grooves 2 are formed in the peripheral direction P of a tire and in the cross direction Q of the tire on a tread 1, whereby many blocks 3 are formed as a tread land portion surrounded by each tread groove 2. Each sipe 4 of a suitable depth is formed on the grounding surface side of each block 3. In this case, each sipe 4 is formed in such a manner as to continuously alternate with a narrow sipe portion 4A and a wide sipe portion 4B. By this arrangement, at the time of braking during running on an icy road surface or the like, good drain efficiency is secured between the tread land portion 3 and the road surface by the wide sipe portion 4B so as to improve braking performance of the tire.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tread structure for an automobile tire, particularly a pneumatic tire.

(Prior art) Winter tires include spike tires with spike pins and so-called studless tires without spike pins.Spike tires have better braking performance on compacted snow and frozen roads in winter. Are better.

However, in recent years, dust pollution caused by the spike pins of spiked tires has become a problem, and regulations on the use of spiked tires are being considered.

Therefore, there is a demand for making the performance of studless tires as close as possible to that of spiked tires, so that even studless tires can exhibit good performance on compacted snow and frozen roads in winter.

By the way, when driving on a compressed snow road or frozen road, the frictional force between the tires and the road becomes small around 0°C;
This is thought to be due to the presence of a film of water from melted snow and ice between the tires and the road surface. Therefore, in order to improve the braking performance by increasing the frictional force between the tires and the road surface, it is necessary to eliminate the water belly interposed between the tires and the road surface.

Methods to eliminate this water belly include draining water through the tread grooves, forming sipes in each block surrounded by the tread grooves to drain water in the contact area, and draining water through microbubbles in the rubber of the tire material. There is a technology to do that.

(Problems to be Solved by the Invention) However, the method of draining water using tread grooves is not effective at all on the contact surface in the full lock state during braking, and the method of draining water using sipes
Because the block is uniform in size and narrow, the block deforms during braking and closes the opening on the contact surface side, resulting in insufficient drainage effect. Furthermore, according to the method of draining water using microbubbles, only microscopic bubbles can be formed due to wear resistance and block rigidity, resulting in insufficient drainage effect.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to ensure water drainage during braking and improve braking performance by changing the shape of the sipes.

(Means for Solving the Problem) The technical means is a tread structure of an automobile tire in which a sipe 4 communicating with the tread groove 2 is formed in a tread land portion 3 surrounded by a tread groove 2. 4
The main feature is that narrow sipe portions 4A and wide sipe portions 4B are alternately and continuously provided.

(Function) According to the present invention, the sipes 4 formed on the tread land portion 3
The tread land portion 3 is formed by alternating and continuous narrow sipe portions 4A and wide sipe portions 4B, and the tread land portion 3 deforms during braking to close the opening of the narrow sipe portion 4A on the ground contact side. Even in this case, the opening on the contact surface side of the wide sipe portion 4B is maintained in an open state, so the water between the tire and the road surface is sucked using the wide sipe portion 4B, and the water is absorbed into the road surface. It is possible to ensure the drainage of water between the wheels, and a good braking effect can be achieved.

(Example) Hereinafter, a first example of the present invention will be described based on the drawings.
FIG. 1 shows a developed view of the tread pattern of a block type pneumatic tire, and FIG. 2 shows a partially enlarged view of the tread 1. FIG. A plurality of tread grooves 2 are formed in the tread l in the tire circumferential direction 9 and the tire width direction Q,
A large number of blocks 3 are provided as tread land portions surrounded by each tread groove 2.

A sipe 4 of an appropriate depth is formed on the ground contact side of each block 3, and at least one end of the sipe 4 of each block 3 on the center side is formed to communicate with the tread groove 2. Further, the sipes 4 are formed in a zigzag shape that is bent alternately in the tire circumferential direction and the tire axial direction, and each sipe 4 has a narrow sipe portion 4A of an appropriate length and a wide sipe portion 4B of an appropriate length. are provided alternately and in a continuous manner.

The width of each sipe portion 4A, 4B is, for example, the groove width of the narrow sipe portion 4A is about 0.6as to 0.81,
The groove width M of the wide sipe portion 4B is wider than the groove width of the narrow sipe portion 4^, and is desirably about 1.2 to 2 times the groove width of the narrow sipe portion 4A.

The first embodiment of the present invention is constructed as described above, and O
``When driving on a compacted snow road surface or frozen road surface with a degree near CC, there is a water belly made of melted snow and ice between the block 3 that has touched the ground and the road surface, but the water that exists between this road surface is Water is well drained to the tread groove 2 side through the sipes 4 of the block 3 communicating with the tread groove 2. Also, each sipe 4 has narrow sipe parts 4A and medium wide sipe parts 4B in a continuous manner alternately. Therefore, even if the block 3 deforms during braking and closes the opening on the ground side of the narrow sipe part 4A, the opening on the ground side of the wide sipe part 4B remains open. Water between the road surfaces is sucked into the wide sipe portion 4B, and the water between the road surfaces can be effectively drained, thereby improving braking performance.

3 and 4 show a second embodiment and a third embodiment, in which the shape of the block 3 and the shape of the sipe 4 are different from the structure of the first embodiment.

Further, in the third embodiment, the sipes 4 are formed in a zigzag shape that is inclined with respect to the circumferential direction P.

Note that the shape of the block 3 and the shape of the sipe 4 are not limited to those in each of the above embodiments, and the sipe 4 does not need to be provided in all blocks 3, but may be provided in the majority of the blocks 3. It's okay to have something. It can also be used for studless tires and snow tires with various tread shapes, and can even be used for spiked tire treads.

(Effects of the Invention) According to the present invention, in the tread structure of an automobile tire in which a sipe communicating with the tread groove is formed in a tread land portion surrounded by a tread groove, the sipe has a narrow sipe portion and a wide sipe portion. It is comprised of alternating and continuous sipe parts, and when braking when driving on packed snow or frozen roads,
The medium-wide sipes effectively ensure drainage between the tread land area and the road surface, improving braking performance.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is a developed view of the tread pattern of the first embodiment, FIG. 2 is an enlarged view of the same part, and FIG.
FIG. 4 is a plan view of a block showing the second embodiment and the third embodiment. 1... Tread, 2... Tread groove, 3... Block, 4... Sipe, 4A... Narrow sipe part, 4B
...Wide sipe section.

Claims (1)

[Claims] (1) Tread land area (3) surrounded by tread grooves (2)
In the tread structure of an automobile tire in which a sipe (4) communicating with a tread groove (2) is formed, the sipe (4) has a narrow sipe portion (4A) and a wide sipe portion (4B).
) in an alternating and continuous manner.