JP2010274800A - Pneumatic tire and tire vulcanizing mold for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire compatibly satisfying in high dimension hydroplaning resistance performance during turn traveling and during straight-ahead traveling on a wet road surface; and a tire vulcanizing mold for manufacturing the pneumatic tire. <P>SOLUTION: A small element group 1 is disposed by collectively arranging on a tread surface a plurality of mutually independent polygonal small elements 4 having a polygonal number of square or more, which are divided by sipes extending linearly. These small elements 4 are divided by a repetitive arrangement of two types of sipes having different widths. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire with improved hydroplaning resistance during straight running and turning on a wet road surface, and a tire vulcanization mold for manufacturing the pneumatic tire. .

  In order to reduce hydroplaning, conventionally, it has been studied how to quickly remove water intervening between the tread tread and the road surface.For example, a tread pattern with a large groove or direction is adopted on the tread tread. To improve drainage efficiency, or to provide a sipe on the tread tread block, to exert an edge effect on the corner formed by the sipe, and to cut the water film with the edge and catch the road surface. Generally, the so-called edge effect that increases the frictional force is improved.

  For example, in Patent Documents 1 and 2, as shown in a partial development view of a tread pattern of a conventional pneumatic tire in FIG. 3, a small block 24 is partitioned into a hexagonal shape with a narrow sipe 23 on the tread surface, A technique has been proposed in which the edge effect or uneven wear resistance is increased by arranging at a high density.

However, in the tires disclosed in Patent Documents 1 and 2, when the tread surface is deformed during braking or cornering, the edge effect may be reduced by half by closing the sipe wall of the narrow sipe 23 provided on the tread surface. was there.
In addition, since the arrangement of the sipe has a shape in which the blades of the mold forming the sipe intersect, for example, two types of blades having different shapes such as the blade forming the sipe described in Patent Document 3 are used. Techniques for layering have been proposed, but their construction has been difficult due to the complexity of the structure of these blades.

JP-A-8-40021 Japanese Unexamined Patent Publication No. 8-324221 JP 2000-43049 A

  Accordingly, an object of the present invention is, in particular, a pneumatic tire capable of achieving a high level of anti-hydroplaning performance at the time of turning and traveling straight on a wet road surface, and a tire vulcanizing mold for manufacturing the pneumatic tire. Is to provide.

  The pneumatic tire according to the present invention is formed by arranging a plurality of polygonal small elements independent of each other and having a number of squares or more divided by sipes extending in a straight line on the tread surface. A small element group is provided, and the small element is divided by repeated arrangement of two types of sipes having different widths.

Here, “two types of sipes having different widths” are composed of two types of sipes of a wide width and a narrow width, and the wide sipes have a width approximately twice that of the narrow sipes.
This wide sipe is an industrial standard effective in the area where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) YEAR BOOK, in Europe ETRTO (European Tire and Rim Technical Organization) STANDARDDS MANUAL, In the United States, tires are assembled to rims specified in TRA (THE TIRE and RIM ASSOCIATION INC.) YEAR BOOK, etc., and the maximum load is specified by JATMA and other standards according to the tire size and the maximum load. In the case of load rolling under capacity, the sipe wall does not close within the ground plane, while the narrow sipe means that the sipe wall closes within the ground plane.

  The tire vulcanization mold according to the present invention comprises a plurality of sipe-forming blade pieces projecting inward from the molding surface of the mold, and the blade pieces together define a surrounding space. The blade piece is formed in a zigzag manner in the longitudinal direction through the concavo-convex portion, and is formed by joining at least the end portions of the concave portion and the convex portion of the pair of blade pieces facing each other. It is.

  In the pneumatic tire of the present invention, each small element having a polygonal shape is partitioned by repeated arrangement of two types of sipes having different widths, so that the contact shape of the tread tread changes when the tire rolls. Even when the sipe wall of the narrow narrow sipe is closed, the gap between the sipe walls of the wide and wide sipe is secured, and the water intervening between the tread tread and the road surface is inserted in the gap. In addition to draining the water with the rotation of the tire, the water drainage of the tire can be improved and the water film cutting function of the edge portion remaining in the small element adjacent to the gap is exhibited. Therefore, excellent hydroplaning performance can be ensured.

  Further, in manufacturing such a tire, the blade pieces together define a surrounding space, and the blade pieces continuously zigzag in the longitudinal direction through the uneven portions, and the recesses of the pair of blade pieces facing each other. By using a tire vulcanization mold in which at least end portions of each of the convex portions are joined, only one kind of blade piece having the same shape, and the blade piece and the blade piece inverted in the width direction, So-called honeycomb blades having a polygonal surrounding area can be easily manufactured.

It is a partial development view of a tread pattern showing one embodiment of a pneumatic tire of the present invention. It is a perspective view which shows one Embodiment of the blade for tire vulcanization molds of this invention. It is a partial expanded view of the tread pattern of the conventional pneumatic tire.

Hereinafter, the pneumatic tire of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partial development view of a tread pattern showing one embodiment of the pneumatic tire of the present invention.
Since the reinforcing structure inside the tire is the same as that of a general radial tire, for example, illustration is omitted.

  In the figure, reference numeral 1 denotes a small element group as a part of the tread surface. The small element group 1 includes a linear wide sipe 2 extending in the tread circumferential direction and four ends from the end of the wide sipe 2 in the figure. A linear narrow sipe 3 extending in the direction is disposed.

  As a result, as shown in the figure, a small element group in which small elements 4 having a hexagonal shape are defined by two wide sipes 2 and four narrow sipes 3, and these small elements 4 are closely packed. 1 is formed in a honeycomb shape.

  For example, by arranging the small element group 1 as shown in FIG. 1 at least over the entire tread surface, the hydroplaning resistance can be improved and the bending rigidity can be made uniform.

  Here, each of the wide sipes 2 has a width of, for example, 0.6 to 2.0 mm, a depth of 3 to 10 mm, and an extension length of 5 to 30 mm. The width is 0.3 to 1.0 mm, the depth is 3 to 10 mm, and the extension length is 5 to 30 mm.

  In the present invention, the small element group 1 is provided not only on the entire tread tread but also on a part thereof, small elements having different surface areas in the tread circumferential direction or the width direction, a hexagonal shape, a rectangular shape, etc. It is also possible to form a polygonal shape, to provide a circumferential groove or a lateral groove on the tread surface, to incline the sipe in the tread circumferential direction, or to combine them.

Next, FIG. 2 is a perspective view showing one embodiment of a blade for a tire vulcanization mold according to the present invention.
In the figure, reference numeral 11 denotes a blade piece, and the blade piece 11 has a zigzag continuous shape in the longitudinal direction via the concave portion 12 and the convex portion 13.
In this blade piece 11, it is only necessary that the concave portions 12 and the convex portions 13 are alternately arranged (staggered), and the side surfaces of the concave portions 12 or the convex portions 13 are formed by a plane, a plurality of bent surfaces, or a curved surface. Can do.

And this blade for tire vulcanization molds divides the surrounding space with the two blade pieces 11 together, and the blade pieces 11 are each of the concave portions 12 and the convex portions 13 of the pair of blade pieces 11 facing each other. At least the ends, preferably the whole are joined.
The blade pieces 11 are preferably joined together by laser welding in terms of certainty and ease after joining.

  By providing such a blade for a tire vulcanization mold on the inside from the inner peripheral surface of a plurality of sector molds that vulcanize the tread rubber of a raw tire, the blade embedded in the tread rubber is embedded. When the blade is pulled out, the blade cuts the tread rubber, so that the blade can form a sipe to form a tread pattern as shown in FIG.

  Next, a tire having a size of 195 / 65R15 and having a tread pattern as shown in FIG. 1 on the entire tread surface, and a comparative example tire having a tread pattern as shown in FIG. Then, the hydroplaning performance was evaluated.

(Hydroplaning performance)
Each of the above example tires and comparative example tires was mounted at a rim size of 6 J × 15 and a tire pressure of 210 kPa, accelerated on a wet straight road surface with a water depth of 2 mm, and compared and evaluated the speed at which the tires idled. Is shown in Table 1. The evaluation in Table 1 indicates that the larger the numerical value, the better.

  From the results shown in Table 1, the example tires have improved hydroplaning performance compared to the comparative tires.

DESCRIPTION OF SYMBOLS 1 Small element group 2 Wide sipe 3,23 Narrow sipe 4 Small element 11 Blade piece 12 Concave part 13 Convex part 24 Small block

Claims (2)

Pneumatic with a small element group consisting of a plurality of small polygonal elements separated from each other by a straight line extending sipes on the tread surface. In the tire,
A pneumatic tire characterized in that a small element is partitioned by repeated arrangement of two types of sipes having different widths. In the tire vulcanization mold comprising a plurality of blade pieces for sipe formation that protrude inward from the molding surface of the mold,
The blade pieces together define a surrounding space, and the blade pieces are zigzag continuous in the longitudinal direction through the concavo-convex portions, and at least the ends of the concave portions and the convex portions of the pair of blade pieces facing each other. Tire vulcanization mold characterized by joining parts.

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