JPH058608A - Main wheel penumatic radial tire for vehicle running on rail - Google Patents

Abstract

PURPOSE:To prevent an advance of the edge wearing-off of a cap tread to the inner side in the tire width direction, as well as to suppress the generation of a partial friction by reducing the cornering force. CONSTITUTION:The carcass 12 of a main wheel pneumatic radial tire 10 for vehicle running on rails is made into one sheet or more, and its belt layer 14 is composed of three belt layers 18, 20, and 22 which consist of cords facing in the direction crossing the tire equator surface 16. And the innermost layer 18 of the belt layers is made in a hollow structure. A tread 24 is composed in a double-layer structure of a cap tread 26 and a base tread 28. And to the tread 24, small grooves 30 are formed extending linearly in the tire circumferential direction, at the positions separated 2mm or more to the center side in the tire radius direction, and 5mm or more to the outer side in the tire radius direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main wheel pneumatic radial tire for a track running vehicle used as a main wheel tire of a new transportation system vehicle such as a subway or a monorail.

[0002]

2. Description of the Related Art Conventionally, the tire shown in FIG. 2 is known as an example of a main wheel pneumatic radial tire for a track running vehicle which is used as a main wheel tire of a new transportation system vehicle such as a subway or a monorail. There is.

As shown in FIG. 2, the tire 70 is
The carcass 72 is made up of one or more carcass plies, and the outer layer side of the crown portion of the carcass 72 is
A belt 74 is arranged.

The belt 74 comprises three belt layers 76, 7
The cords of the belt layers 8 and 80, for example, steel cords, are arranged in the direction intersecting the tire equatorial plane 82, as shown in the upper part of FIG. Further, the tread portion 8 is provided on the outer layer side of the belt 74.
4 are arranged.

[0005]

However, in the conventional tire 70, when the track running vehicle meanders due to the action of the guide wheel that comes into contact with the side wall of the track, the guide plate, etc., load rolling is performed. A large cornering force is generated on the tire 70. Therefore, the tire tread receives a large input from the road surface, and this input causes the side end portion of the tread 84 to be dragged, and edge drop wear is likely to occur unevenly on the tire circumference. Further, this edge drop wear, that is, uneven wear progresses inwardly in the width direction in the tread 84 very early, and the tire shape becomes polygonal. There was a problem that the vibration of the vehicle increased.

In consideration of the above facts, the present invention reduces the cornering force to suppress the occurrence of uneven wear, and at the same time, prevents the edge wear of the cap tread from advancing inward in the tire width direction. The purpose is to obtain a pneumatic radial tire for a traveling vehicle.

[0007]

According to the present invention as set forth in claim 1, a pair of beads, one or more carcass plies, a belt layer having three or more intersecting layers including intersecting layers, and a base tread. In a pneumatic radial tire for main wheels of a track vehicle, comprising two or more layers of treads each provided with a cap tread, an inner hollow structure in which a central portion in the tire width direction is removed from the innermost layer of the belt layers. 2 mm from the side edge of the outermost layer of the belt layer to the tire center side
The above feature is characterized in that a thin groove extending in the tire circumferential direction is provided in the crown portion which is separated from the tire radial direction outward by 5 mm or more.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the JIS hardness of the base tread is 55 ° to 75 °.

According to the present invention of claim 3, in the invention of claim 1, the volume ratio of the base tread to the entire volume of the crown tread is 20 to 60%.
It is characterized by

[0010]

In the pneumatic radial tire for main wheels of a track running vehicle according to claim 1 of the present invention, the cornering force of the tire can be reduced by making the innermost belt a hollow structure. In addition, since the innermost belt has the hollow structure, the original function of the belt layer is not lost, and the rigidity of the tread side end portion and the durability of the belt are not deteriorated.

Therefore, it is possible to prevent uneven wear due to the tire tread receiving a large input from the road surface.

Further, in the pneumatic radial tire for main wheels of a track vehicle according to the present invention, the crown portion is separated from the side edge of the outermost layer of the belt layer by 2 mm or more to the tire center side and 5 mm or more to the outside in the tire radial direction. Further, the narrow groove extending in the tire circumferential direction can prevent the edge falling wear generated at the end portion on the tread side from proceeding inward in the tire width direction. Therefore, the crown portion positioned on the outer side in the tire width direction from the narrow groove causes edge drop wear by counteracting the side force input, but the crown portion positioned on the inner side in the tire width direction from the narrow groove does not respond to the side force input. In addition to the small load, the narrow groove prevents the wear of the edge from occurring in the crown portion located outside the narrow groove in the tire width direction. For this reason, the crown portion located outside the narrow groove in the tire width direction exhibits a uniform wear pattern, and the wear of the diagonal wear can be prevented.

Here, the narrow groove is provided at a position separated from the side edge of the outermost layer of the belt layer by 2 mm or more toward the tire center side and 5 mm or more outwardly in the radial direction of the tire. When it is provided on the outer side, the lateral input at the time of cornering cannot be fully covered, and the edge drop wear progresses to the inner side in the tire width direction of the narrow groove. This is because when they are arranged, cracks occur at the bottoms of the narrow grooves due to strain at the side edge of the outermost layer of the cross belt layer.

Further, in the main wheel pneumatic radial tire for track running vehicle according to claim 2 of the present invention, the JIS hardness (JIS hardness K6301 spring type hardness test A type) of the base tread is 55 ° to 75 °. The reason is that when the JIS hardness of the base tread is less than 55 °, the wear resistance deteriorates, and when the JIS hardness of the base tread is greater than 75 °, the cornering force increases.

In the pneumatic radial tire for main wheels for track running vehicles according to claim 3 of the present invention, the volume ratio of the base tread is set to 20 to 60% with respect to the entire volume of the crown tread. This is because when it is smaller than 20, the effect of reducing the cornering force is not sufficient, and when it is larger than 60, the wear durability of the tread portion is deteriorated. The volume ratio of the base tread is preferably 30 to 50% with respect to the entire volume of the crown tread.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a main wheel pneumatic radial tire 10 for a track running vehicle (hereinafter referred to as main wheel tire 10) according to this embodiment.

As shown in FIG. 1, the carcass 12 of the main wheel tire 10 is formed by one or more carcass plies consisting of cords extending in the radial direction of the tire, and the carcass 12 has a crown portion on the outer layer side. Is the belt layer 1
4 are arranged. The belt layer 14 is composed of three belt layers 18, 20, 22 each of which is composed of a cord oriented in a direction intersecting with the tire equatorial plane 16.

Of these belt layers 18, 20, 22, the innermost belt layer 18 has a hollow structure in which the central portion in the tire width direction is removed. The width W2 of the intermediate belt layer 20 is equal to the width W of the other belt layers 18 and 22.
1, wider than W3. Also, the belt layers 18 and 2
The angle of intersection of 0 and 22 with the tire equatorial plane 16 is, for example,
The cords of the innermost belt layer 18 are inclined upward to the right at an angle θ1, the cords of the intermediate belt layer 20 are inclined upward to the right at an angle θ2, and the cords of the outermost belt layer 22 are inclined upward to the left. The angle is θ3. The angle of intersection of the belt layers 18, 20, 22 with the tire equatorial plane 16 is
Contrary to the present embodiment, the cords of the innermost belt layer 18 and the cords of the intermediate belt layer 20 may be raised to the left and the cords of the outermost belt layer 22 may be raised to the right.

Further, the tread portion 24 of the main wheel tire 10
Has a two-layer structure of a captread 26 that constitutes the tread surface of the tread portion 24 and a base tread 28 that is arranged on the belt layer 14 side of the captread 26. The capto red 26 is made of a wear-resistant rubber material, and the base tread 28 has a JIS hardness of 55 ° to
A rubber material having a crack growth resistance of 75 ° and a resilience of 55 or more is used. The volume ratio S of the base tread 28 to the entire volume of the crown tread is 20 to 60%.

The tread portion 24 has a thin line extending linearly in the tire circumferential direction from the side end 22A of the outermost layer belt 22 at a position 2 mm or more toward the tire center side and 5 mm or more outwardly in the tire radial direction. The groove 30 is formed. The narrow groove 30 is 0.5 mm-2.
It has a groove width L of 5 mm and a thickness M of the capto red 26 of 7
The depth D is 0% or more and may reach the base tread 28.

In the main wheel tire 10 thus constructed, due to the hollow structure of the innermost belt layer 18, a cornering force unnecessary for this type of tire is provided.
The rigidity of the tread portion 24 and the durability of the belt can be effectively reduced without sacrificing the uneven wear of the tire.

Further, in the main wheel tire 10 of this embodiment, the action of the narrow groove 30 completely prevents the edge falling wear generated at the side end portion of the tread portion 24 from proceeding inward in the tire width direction. be able to.

Further, in this embodiment, since the resilience of the base tread 28 is 55 or more, the tire durability can be improved without impairing the heat resistance.

In this embodiment, the main wheel tire 1
Although 0 is a slick tire, the main wheel tire 10 is not limited to this, and the toledo pattern may be a block pattern, a lug pattern, or the like. Alternatively, it may be a combination pattern of two or more types of patterns. (Test Example) The tire of the present invention shown in FIG. 1 and the tire of the conventional example shown in FIG. 2 (each tire has a size of E8R22.5,
A rim assembled on a 6.25 × 22.5 rim with a filling internal pressure of 7.75 kg / cm ² . ) For each of the specifications shown in Table 1, measure the side force of each tire, and attach each tire to the drive wheels of a heavy-duty vehicle to make it similar to the running conditions when attached to the drive wheels of a subway. Then, the state of occurrence of diagonal wear after traveling 100,000 km was visually inspected, and the results are shown in Table 1.

[0026]

[Table 1] From the experimental results shown in Table 1, it became clear that the present invention is particularly excellent.

[0027]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned structure, it is possible to reduce the cornering force to suppress the occurrence of uneven wear and to prevent the edge wear of the cap tread from advancing inward in the tire width direction. .

[Brief description of drawings]

FIG. 1 is a diagram showing a main wheel pneumatic radial tire for a track vehicle according to an embodiment of the present invention.

FIG. 2 is a view showing a main wheel pneumatic radial tire for a track running vehicle according to a conventional example.

[Explanation of symbols]

Main tire pneumatic radial tire for 10-track running vehicle 12 carcass 14 Belt layer 18 Innermost belt layer 20 Intermediate belt layer 22 Outermost belt layer 16 tire equatorial plane 24 tread section 26 capto red 28 base tread 30 narrow groove

Claims (3)

[Claims] 1. A pair of beads, one or more carcass plies, a belt layer having three or more intersecting layers including an intersecting layer, a base tread and a cap tread.
In a pneumatic radial tire for tracked vehicles having a layer or more treads, the innermost layer of the belt layer has a hollow structure in which the central portion in the tire width direction is removed, and the belt layer A main wheel for a track running vehicle characterized in that a narrow groove extending in the tire circumferential direction is provided in a crown portion which is separated from the side edge of the outermost layer by 2 mm or more toward the tire center side and 5 mm or more outward in the tire radial direction. Pneumatic radial tire. 2. The JIS hardness of the base tread is 55.
The pneumatic radial tire for main wheels for a track vehicle according to claim 1, wherein the pneumatic radial tire is set in a range of 90 ° to 75 °. 3. The main wheel pneumatic radial tire for a track vehicle according to claim 1, wherein the volume ratio of the base tread to the entire volume of the crown tread is 20 to 60%.