JPS62275806A - Pattern for pneumatic tire - Google Patents

Abstract

PURPOSE:To check any drop in block rigidity and secure a yet more effective tread pattern for reducing a shear noise, by installing a rib train provided with a shallow groove which is substantially continued in the tire circumferential direction so as to be crossed with a sipe. CONSTITUTION:At a tread part, in each rib 1, there is provided with each sipe 2 which is not opened to adjacent circumferential main grooves 4. And, in this tread part, there are provided with a shallow groove 3 in parallel with the circumferential direction and the main groove 4 in parallel with the circumferential direction too. That is to say, there is provided with such a shallow groove 3 that opens the air sealed inside the sipe 2 to a space being crossed with the sipe 2 and adjoining to a grounding part. With this constitution, the air inside the sipe 2 is always dischargeable even when the tire is grounded, whereby sudden discharge at the time of kicking off is thus reduced. At this time, this shallow groove 3 is required to have a clearance between its wall and a road surface without making groove walls contact with each other under the grounding surface at the time of load rolling.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) A pneumatic tire installed on a car suppresses high-frequency noise (shearing noise) generated on a smooth asphalt road surface, especially during acceleration. , which it seeks to advantageously reduce.

(Prior Art) A pneumatic tire having a rib pattern generally has a large number of radially extending sipes within each rib.

Generally speaking, this type of sipe is divided into sipes that open in the main groove that borders the block and sipes that do not, but in particular, sipes that open in the main groove have divided ribs, resulting in reduced rigidity and stable handling. This resulted in a negative impact on sexuality.

(Problems to be Solved by the Invention) This type of tire, which uses many unopened sipes, has a problem with high-frequency noise (shearing noise) that occurs on smooth asphalt roads, especially during acceleration.

Therefore, it is an object of the present invention to provide a more effective tread pattern for eliminating the above-mentioned drawbacks, suppressing a decrease in block rigidity, and reducing shear noise.

(Means for Solving the Problems) As a result of various studies, the inventors of the present invention found that one of the causes of these shearing noises is the rapid discharge of air sealed between the sipes and the road surface.

Therefore, the present invention provides a shallow groove that intersects the sipe and opens into a space adjacent to the ground contact area, so that the air sealed in the sipe can be kept at all times even when the tire is in contact with the ground. Since it can be discharged, sudden discharge during kicking can be reduced. In this case, it is necessary that the shallow grooves have a gap between them and the road surface so that the groove walls do not come into contact with each other under the ground contact surface during load transfer.

The tread surface has at least one row of ribs extending in the circumferential direction, and at least a plurality of ribs are arranged in the rib row in a direction intersecting the circumferential direction of the tire and do not open into adjacent grooves that partition the rib rows. The problem was solved by providing a pneumatic tire pattern having sipes with a lip row having a shallow groove substantially continuous in the circumferential direction of the tire so as to intersect with the sipes.

The sipe consists of one or more sipes and has a depth of 10% or more of the depth of the adjacent main groove that partitions the block.

The shallow groove has a width such that the groove walls at least do not contact each other under the ground contact surface during load rolling, and a depth such that there is a gap between the groove walls and the road surface.

(Function) By providing a shallow groove that intersects with the sipe and opens into the adjacent groove, the air inside the sipe can be constantly discharged to the #contact groove even when the tire is in contact with the ground, resulting in rapid discharge when kicking off. is reduced.

In this case, the shallow groove needs to have a gap between it and the road surface so that the air sealed in the sipes under the ground contact surface does not come into contact with each other under the ground surface during load transfer.

(Example) The present invention will be explained in detail based on examples.

FIG. 1 is a partially exploded view showing a tread surface portion of the present invention.

Tire Sipe: PI35/80R-13■ indicates a rib, and each rib is provided with a sipe (■) that does not open into the adjacent circumferential main groove (■). ■ indicates a non-opening sipe that intersects a shallow groove in the circumferential direction, ■ indicates a shallow groove parallel to the circumferential direction, ■ indicates a main groove parallel to the circumferential direction, and consists of four pieces of wood.

The sipe (3) has a width of 0.5 ms and a depth of S layer/co.

The width of the shallow groove parallel to the circumferential direction is 21/mu and the depth is 1.
5 intestines/intestines. The shallow groove preferably has a width IIl/11 to 5
m/s, the depth is preferably Is/m to 3 m/m, and the main groove parallel to the circumferential direction of ■ is 5.5 layers/- in width and 9 layers/layer in depth.

The depth of the shallow groove will vary depending on the tire sipe, but it needs to be deep enough to allow air to escape when it touches the ground.

(Effects of the Invention) FIG. 3 shows the results of frequency analysis of in-vehicle sound when shearing noise occurs between the tire of the present invention (broken line) and the conventional tire (solid line).

Shearing sound evaluation test method - While driving at a constant speed (60 km), the accelerator is fully depressed and the gear is 3rd. Measuring the sound inside the car during acceleration ■Divide the above data into minute periods.

■ Frequency analysis of all data in the section from 70 km/h to 80 km/h and the spectra are averaged.

■Refining the 3-5kHz component of the averaged spectrum. (Band RMS value) The conventional tire differs from the tire of the present invention only in that it does not have shallow grooves parallel to the circumferential direction shown in FIG. 1, and is otherwise the same as the tire of the present invention.

3-5k) I which is an evaluation measure of shear sound as an effect
The Z band RMS value is 58.1 dB (A
), the tire of the present invention was 52.7 dB (B) and 3.4
dB(A) is also reduced. Moreover, other performances (wet performance, etc.) are almost the same as conventional tires.

[Brief explanation of the drawing]

FIG. 1 is a partially exploded circumferential view of the tire of the present invention. ■・・・Tread ribs ■・・・Circumferential main grooves ■・・・Sipes ■・・・Shallow grooves Figure 2 shows the A- of the center rib in Figure 1. FIG. 3 is a circumferential cross-sectional view of AMt. FIG. 3 is a diagram showing the effects of the tire of the present invention and the conventional tire. The wavy line represents the tire of the present invention, and the solid line represents the frequency analysis of the sound inside the car when a conventional tire generates a shearing noise. Patent applicant Brideston Co., Ltd. Figure 1

Claims (1)

[Scope of Claims] 1. The tread has at least one row of ribs extending in the circumferential direction on the tread surface, and is arranged in the rib row in a direction crossing the tire circumferential direction, and has adjacent grooves that partition the rib rows. A pneumatic tire pattern that does not open and has at least a plurality of sipes, characterized by having a rib row having a shallow groove that is substantially continuous in the tire circumferential direction so as to intersect the sipes. tire. 2. The pneumatic tire according to claim 1, characterized in that the sipe consists of one or more sipes and has a depth of 10% or more of the depth of the adjacent main groove that partitions the rib. 3. In Claim 1, the shallow groove is characterized by having a width such that the groove walls do not come into contact with each other under the ground surface during load rolling, and a depth such that there is a gap between the groove walls and the road surface. pneumatic tires.