JPH0338408A - Tire for floating type vehicle - Google Patents

Abstract

PURPOSE:To improve durability by forming a groove by a predetermined area proportion in the predetermined area at the end portion in the width direction of a tire, and setting a width outer circumferential curvature semidiameter of a center side larger than that of the end portion bounded by a predetermined boundary point, in a tire for a linear motor, etc. CONSTITUTION:A groove formed portion 34 is formed at an end portion side bounded by a position apart 60% of half of the ground width toward the end portion in the width direction from a central portion in the width direction within the limit of the ground width under 100% load, and a circumferential groove 30 having 20%-50% area compared with the area of the groove formed portion 34 is formed. A semidiameter R1 of curvature at a tire center portion side in an outer circumferential curvature semidiameter is set larger than a semidiameter at a width end portion side bounded by a position 36 apart 40%-70% of half of the ground width C toward the end portion side in the width direction from the width directional center portion of a tread 22 under 100% load. According to this construction, the reduction of heat accumulated quantity and the reduction of cooling effect can be achieved so that durability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a floating vehicle tire that is applied to a floating vehicle such as a linear motor car.

[Conventional technology]

2. Description of the Related Art In floating vehicles such as linear motor cars, tires are used until the vehicle body floats while traveling and when it comes down to the ground when stopped.

This type of tire has a characteristic that the center part in the width direction wears more than the ends in the width direction due to the difference in outer diameter between the center part in the width direction and the end part in the width direction. The other end is curved with a large radius of curvature over the entire width direction.

However, in this structure, the ends in the width direction become thick, which adversely affects durability. That is, if the widthwise ends are within the thickness, heat due to distortion during running tends to accumulate, causing separation.

[Problem to be solved by the invention]

The present invention has been made in consideration of the above-mentioned facts, and an object of the present invention is to obtain a floating vehicle tire that can improve durability.

[Means to solve the problem]

In the floating vehicle tire according to the present invention, the width is within the range of the ground contact width at 100% load, and the width is set at a position 60% away from the 1/2 ground contact width from the center part in the width direction to the end part in the width direction. A groove forming portion is formed on the direction end side, and a groove having a ratio of 20% to 50% of the area of the groove forming portion is provided in the groove forming portion, and 172
The radius of curvature of the outer circumference in the width direction on the center side in the width direction and on the end side in the width direction is changed from a position separated by 40% to 70% of the ground contact width to change the radius of curvature of the outer circumference in the width direction on the widthwise end side to the center side in the width direction. It is characterized by having a radius of curvature smaller than the outer curvature radius in the width direction of the sides.

[Effect]

In the present invention having the above-mentioned configuration, the width direction edge side is located within the range of the ground contact width at 100% load and is located at a position 60% away from the width direction center part to the width direction end part as the border. Since a groove forming part is formed in the groove forming part and the ratio of the area of the groove forming part to the area of the groove forming part is 20% to 50%, the volume of the end in the width direction is reduced by the groove, and the amount of heat storage is reduced. At the same time, airflow passes through the grooves, providing a cooling effect.

In addition, the radius of curvature of the outer periphery in the width direction is changed between the center part in the width direction and the end part in the width direction, with the boundary between 40% and 70% of the 1/2 ground contact width from the center part in the width direction toward the ends in the width direction. Since the widthwise outer circumferential curvature radius on the widthwise end side is made smaller than the widthwise outer circumferential curvature radius on the widthwise center side, this change in curvature also makes the widthwise end portion thinner and reduces the amount of heat storage.

〔Example〕

1 and 2 show the cross-sectional shape (hatching of the rubber portion is omitted) of a radial tire 20 for a linear motor car to which the present invention is applied.

As shown in FIG. 2, in this radial tire 20,
A belt 24 is arranged inside the tread 22.

The belt 24 is a belt in which cords are crossed at a predetermined inclination with respect to the tire circumferential direction, and are arranged in layers in the tire radial direction.

A carcass 26 is arranged inside this belt 24.

The carcass 26 is a carcass in which a plurality of carcass cords 26A are arranged in layers in the tire radial direction. A part of the carcass cord 26A goes around the bead core 28 from the inside to the outside in the tire width direction and is folded back.
The other part goes around the bead core 28 from the outside in the tire width direction to the inside and is folded back. The bead core 28 is arranged in a ring shape around the rotation axis of the radial tire 20.

In the radial tire 20 configured in this way, grooves 30 continuous along the tire circumferential direction are formed on the outer peripheral surface of the tread 22.
is formed, and the outer circumferential curvature of the tread 22 is changed between the end portions in the tire width direction and the center portion in the tire width direction.

To explain in detail, the tread 22 has a ground contact width C of 1/2 from the center in the width direction to the edge in the width direction within the range of the contact width at <100% load as shown in detail in FIG. A groove forming portion 34 is formed on the width direction end side with the portion 32 separated by 60% as a boundary, and the tire circumferential groove 30 has a ratio of 20% to 50% of the area of the groove forming portion 34 to this groove forming portion 34. is provided.

In addition, on the outer circumferential surface of the tread 22, from the center in the width direction to the edge in the width direction, the border is a part 36 that is 40% to 70% away from the 1/2 ground contact width C at 100% load, and the center part in the width direction and the width The widthwise outer circumferential curvature radius on the widthwise end side is different, and the widthwise outer circumferential curvature radius R2 on the widthwise end side is smaller than the widthwise outer circumferential curvature radius R1 on the widthwise center side.

According to the above configuration, a reduction in the amount of heat storage and a cooling effect are obtained, and the occurrence of separation due to heat generation during driving can be prevented and durability can be improved. That is, on the outer circumferential surface of the tread 22, the width is within the range of the ground contact width at 100% load and is separated from the center part in the width direction by 60% of the 1/2 ground contact width C from the center part in the width direction. A groove forming portion 34 is formed on the direction end side, and the groove forming portion 3 is formed in this groove forming portion 34.
Since the grooves 30 have a ratio of 20% to 50% of the area of 4, the grooves 30 reduce the volume at the ends in the width direction.
As the amount of heat storage decreases, airflow passes through the grooves 30, providing a cooling effect. Further, on the outer circumferential surface of the tread 22, the center side and the end side in the width direction are separated from the center part in the width direction by 40% to 70% of the 1/2 ground contact width C from the center part in the width direction to the end part side in the width direction. By changing the widthwise outer circumferential curvature radius of , the widthwise outer circumferential curvature radius R2 on the widthwise end side is made smaller than the widthwise outer circumferential curvature radius R1 on the widthwise center side, so this curvature change also makes the widthwise edge The wall becomes thinner and the amount of heat storage decreases.

Note that the grooves 30 may be provided intermittently in the tire circumferential direction, as shown in FIG.

(Experimental Example) Radial tires 20 according to this example and radial tires with other structures were manufactured under the specifications of Clothing 1 below, and the air pressure was 7.
9kg/c++f, load 2500kg, speed 200
The vehicle was run continuously at a speed of 1 km/h, and was also allowed to take off and land to examine the degree of wear and durability.

The degree of wear was determined by measuring the number of takeoffs and landings until the tires were completely worn out, and the degree of durability was determined by measuring the time until failure occurred.

Table where C is 1 at 100% load (2500kg)
/2 ground contact width dimension, B is the tire width direction dimension from the tire width direction center part to the groove, R1 is the tread outer circumference curvature radius at the tire width direction center part, R2 is the tread outer circumference curvature radius at the tire width direction end part, A is the dimension in the tire width direction from the center in the tire width direction to the boundary portion where the curvature of the tread outer circumference changes when the curvature of the tread outer circumferential surface differs between the tire width direction center and the tire width direction ends.

As a result, as shown in Figure 2 below, it became clear that the radial tire 20 according to this example had excellent durability without being significantly inferior in the degree of wear compared to radial tires with other structures. Ta.

Table 2 [Effects of the Invention] As explained above, the floating vehicle tire according to the present invention has the excellent effect of reducing the amount of accumulated heat and achieving a cooling effect, thereby improving durability.

[Brief explanation of drawings]

1 and 2 show an embodiment of a floating vehicle tire according to the present invention, and FIGS. 1(A) and 2(B) are an enlarged sectional view of the main part of FIG. 3 is a sectional view showing the overall structure, and FIGS. 3(A) and 3(B) are sectional views and tread views showing other embodiments corresponding to FIG. 1. 20...Radial tire 22...Tread 30...Groove 34...Groove forming portion.

Claims (1)

[Claims] (1) Within the range of the ground contact width at 100% load, from the center in the width direction to the edge in the width direction, 6 points of the 1/2 ground contact width
A groove forming part is formed on the end side in the width direction with a position separated by 0% as a border, and the ratio of the area of the groove forming part to the area of the groove forming part is 20.
% to 50% grooves are provided, and the grooves on the widthwise center side and the widthwise end side are set at a position 40% to 70% of 1/2 ground contact width from the widthwise center to the widthwise ends. A floating type vehicle tire characterized in that the radius of curvature of the outer periphery in the width direction is changed so that the radius of curvature of the outer periphery in the width direction on the widthwise end side is smaller than the outer curvature radius in the width direction on the widthwise center side.