JPH0386602A - Heavy load radial tire for floating type vehicle - Google Patents

Abstract

PURPOSE:To improve the abrasion resistance of the center part in the tire width direction by projecting the center part in the tire width direction of a tread part outside in the radial direction within a prescribed range of the width of a belt arranged inside in the tire radial direction of the tread part, a heavy load radial tire for a linear motor car, etc. CONSTITUTION:The width dimension C of a belt layer 50 arranged between a tread part 46 and a carcass 42 is set to about 70 - 95% for the width dimension B of a tire 14, and a projection part 49 is formed towards the outside in the tire radial direction at the center part in the tire width direction of a crown part 48. The width dimension A of the projection part 49 is set to 30 - 70% of the width dimension C of the belt layer 50. With this constitution, the abrasion resistance of the center part in the tire width direction of the crown part can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heavy-load radial tire for a floating vehicle used, for example, during takeoff and landing of a linear motor car that travels while floating due to the action of magnetism.

[Prior art]

Currently, magnetic levitation vehicles (hereinafter referred to as linear motor cars)
is being developed. In this linear motor car, the magnetic force acting between the road surface and the vehicle causes the vehicle to levitate from the road surface, and the magnetic force acting between the side wall and the vehicle provides propulsion to the vehicle, allowing the vehicle to move along the guide path. The vehicle is operated in a non-contact manner. Theoretically, the levitation height should be only a few mm, but taking into account the characteristics of Japan, which has a high number of earthquakes, superconductors are used to create a strong magnetic field in order to achieve a levitation height of about 100 mm. .

Incidentally, in such a linear motor car, it is necessary to support and guide the vehicle with respect to the road surface during takeoff and landing, and tires for the linear motor car have been developed.

As shown in FIG. 3, the load applied to linear motor car tires changes over time.

That is, at the start of takeoff, the linear motor car takes on the full load and gradually rises as the speed increases, so the load applied to the tires gradually decreases, and after takeoff there is no load. Moreover, at the time of landing, contrary to the above-mentioned takeoff, a load is gradually added from an unloaded state as the speed decreases, and after landing, the vehicle receives the full load of the linear motor car. In this way, the load changes over time, which is not the case with tires applied to ordinary automobiles. Furthermore, unlike aircraft tires, tires are in a slipping state with the road surface for a relatively long time in a low load range during landing, so the wear state of the tires is completely different from that of aircraft tires.

For this reason, it is necessary to develop tires specifically for linear motor cars.

However, in such a linear motor car, as mentioned above, when landing, the tires are in contact with the road surface for a relatively long time under a low load, so wear is particularly high in the vicinity of the center portion of the tread portion in the width direction of the tire. For this reason, as shown in FIG. 4, heavy-load radial tires 54 for floating vehicles
It is conceivable to increase the thickness of the tread portion 52 of the vehicle.

However, in this floating type heavy-load radial tire 54 for vehicles, the thickness of the tread portion 52 near the center in the tire width direction (hereinafter referred to as the crown portion) 55 and the vicinity of both ends in the tire width direction (hereinafter referred to as the shoulder portion) 56 As the wall thickness increases, there is a risk that the shoulder portion 56 will generate heat due to repeated loads during tire transfer, and the carcass etc. will peel off, resulting in decreased durability.

[Problem to be solved by the invention]

In consideration of the above facts, the present invention provides a floating vehicle capable of improving the wear resistance of the tread portion near the center portion in the tire width direction without reducing the durability near both ends of the tread portion in the tire width direction. The objective is to obtain a heavy-duty radial tire for use.

[Means to solve the problem]

The present invention is characterized in that the center portion of the tread portion in the tire width direction protrudes outward in the tire radial direction within a range of 30% to 70% of the width dimension of the belt disposed inside the tread portion in the tire radial direction. .

[Effect]

According to the present invention, when the floating vehicle lands, the vicinity of the center in the tire width direction of the tread portion of the tire comes into contact with the road surface in an unloaded and stopped state, and the applied load gradually increases. Here, 3 of the width dimension of the belt disposed inside the tire radial direction of the tread part of the heavy-load radial tire for floating vehicles.
The center portion of the tread portion in the tire width direction protrudes outward in the tire radial direction within a range of 0% to 70%. As a result, the thickness of the tread portion near the center in the tire width direction, which is subject to a lot of wear, becomes thicker, and the wear resistance of the tread portion near the center portion in the tire width direction can be improved. Further, since the wall thickness of the tread portion near both ends in the tire width direction does not increase, heat generation near both ends of the tread portion in the tire width direction is small, and durability is not reduced.

[Embodiments of the invention]

FIG. 2 shows a linear motor car 10 to which the present invention is applied.
It is shown. This linear motor car 10 is supported on a guideway 12 via heavy-load radial tires 14 for floating vehicles. The guideway 12 is a linear motor car 1
Side walls 16 and 18 are erected corresponding to both sides of 0, respectively. A guide tire 20 whose axis of rotation is perpendicular to the road surface is attached to the side surface of the linear motor car 10, and the guide tire 20 is in contact with the side wall 16.18.

A levitation coil 22 is laid on the surface of the guideway 12, and the magnetic force acting between it and a superconducting magnet 24 installed in the linear motor car 10 causes the linear mower 10 itself to be moved approximately 100 mm away from the guideway 12. It is now possible to levitate. Further, a propulsion guide coil 26 is attached to the side wall 16.18, and the linear motor car 10 is propelled by the magnetic force acting between it and a superconducting magnet 24 installed in the linear motor car 10.

Here, the linear motor car 10 is levitated when it reaches a predetermined speed, and when the speed is lower than the predetermined speed, the linear motor car 10 is supported by the heavy-load radial tires 14 for floating vehicles. That is, the heavy-load radial tires 14 for floating vehicles are used for the linear motor car 10 necessary for takeoff and landing of the linear motor car 10.
It has a role as a support body. Incidentally, during normal running, this heavy-load radial tire 14 for a floating vehicle is stored in a storage section (not shown).

As shown in FIG. 1, the shape of the heavy-duty pneumatic tire 14 for floating vehicles consists of a carcass 42 wrapped around a bead core 40 formed in a ring shape around the rotational axis of the tire at both ends in the longitudinal direction, and a rubber layer 44 wrapped around a bead core 40. The rubber layer 44 has a thick-walled tread W 46 at the portion that contacts the guide path 12 (see FIG. 2).

The tread portion 46 has shoulder portions 47 near both ends in the tire width direction where the radius of curvature becomes small, and the portion between the shoulder portions 47 is called a crown portion 48 .

Further, a belt layer 50 is arranged between the tread portion 46 and the carcass 42. The width dimension C of this belt layer 50 is set to be 70% to 95% of the width dimension B of the heavy-load radial tire 14 for floating vehicles.
is designed to reinforce the tread portion 46 of the heavy-load radial tire 14 for floating vehicles.

A protruding portion 49 is formed at the center portion of the crown portion 48 in the tire width direction toward the outside in the tire radial direction. The width dimension A of this protruding portion 49 is set to be 30% to 70% of the width dimension C of the belt layer 50, and is designed to improve the wear resistance near the center portion of the crown portion 48 in the tire width direction. ing.

The operation of this embodiment will be explained below.

First, changes in the load applied to the heavy-load radial tires 14 for floating vehicles when the linear motor car 10 takes off will be explained.

As shown in FIG. 3, when the linear motor car 10 takes off, the load at the start (time t=0) is the load when the vehicle is stopped (vehicle weight, ie, 100% load).

When the linear motor car IO starts running due to the magnetic force acting between the superconducting magnet 24 and the propulsion guide coil 26,
The magnetic force (levitation blade) acting between the superconducting magnet 24 and the levitation coil 22 gradually increases, and the load applied to the heavy-load radial tires 14 for levitation vehicles is equal to the vehicle weight minus the magnetic levitation blade. Therefore, it gradually decreases. Furthermore, the vehicle speed is gradually increased by the propulsion guide coil 26, and when it reaches a certain specified speed, the heavy-load radial tires 14 for floating vehicles are activated.
The load applied to the beam becomes zero, and finally the beam near motor car 10
is raised approximately 100 mm above the surface of the guide path 12, and the vehicle can run at high speed.

Next, changes in the load applied to the heavy-load radial tires 14 for floating vehicles when the linear motor car 10 lands will be explained.

As shown in Figure 3, the load is zero just before the start of landing, but at the time of landing it becomes the value obtained by subtracting the magnetic levitation blade at the landing speed from the vehicle weight, and as the vehicle decelerates further, the magnetic levitation blade decreases, so the levitation increases accordingly. The load applied to the heavy-load radial tires 14 for floating-type vehicles increases, and when the linear motor car 10 continues to decelerate and finally comes to a complete stop, the heavy-load radial tires 14 for floating-type vehicles are loaded with the load (vehicle weight) when the vehicle is stopped. , that is, 100% load) is applied.

In this way, the linear motor car 10 lands while gradually increasing the load, thereby making it possible to land smoothly without causing any shock to the occupants.

Here, at the initial stage when the linear motor car 10 lands, a light load is applied to the heavy-load radial tires 14 for the floating vehicle. Normally, a heavy-load radial tire 14 for a floating vehicle has a regular contact surface (in Fig. 1, the tread is in contact with the ground over its entire width from one end of one shoulder to one end of the other shoulder) when the full load (the above-mentioned 100% load) is applied. In such a low-load state, the crown portion 48 is designed to be on the surface of the guideway 12 before the heavy-load radial tire 14 for floating vehicles reaches the normal ground contact state. contact and wear. Therefore, in this example,
By providing the protruding portion 49 at the center portion of the crown portion 48 in the tire width direction, the wear resistance of the crown portion 48 can be improved.

Further, since the wall thickness of the shoulder portion 47 of the tread portion 46 is not increased, less heat is generated in the shoulder portion 47, and durability is not reduced.

In the above embodiment, the heavy-load radial tire 14 for a floating vehicle was explained, but the side wall 16
．． The same effect can be obtained by adopting a similar configuration for the guide tire 20 that contacts the guide tire 18.

(Experiment Example 1) Example ■, Example ■, Example ■, Comparative Example, Comparative Example ■, and conventional example (Fig. 4), which were prototyped with each specification shown in Table 1.
The number of takeoffs and landings required for each of the heavy-duty radial tires for floating vehicles to reach the specified amount of wear (wear life index)
Table 1 shows the results of measuring the time until failure occurs (durability index) when running continuously at 200 km/h with a regular load of 2500 kg.

Table 1 However, the tire outer diameter :E14wL.

Rim diameter: 14", air pressure: 7.9 kg/c4 The experimental results reveal that the above-described heavy-load radial tire for floating vehicles of the present invention is particularly excellent.

〔Effect of the invention〕

Since the present invention has the above structure, it is possible to improve the wear resistance of the tread portion near the center portion in the tire width direction without reducing the durability near both ends of the tread portion in the tire width direction. have an effect.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the tire according to this embodiment taken along the tire width direction with some hatching omitted, Fig. 2 is a front view of the linear motor car, and Fig. 3 is a cross-sectional view of the tire during takeoff and landing of the linear motor car. FIG. 4, a characteristic diagram showing the applied load, is a sectional view of a conventional tire taken along the width direction of the tire, with some hatching omitted. 10... Linear motor car, 14... Heavy load radial tire for floating vehicle, 20...
・Guide tire, 46・ 47 ・ 48 ・ 49 ・ 50 ・・Tread part, ・Shoulder part, ・Crown part, ・Protrusion part, ・Belt layer.

Claims (1)

[Claims] (1) A floating device characterized in that the center portion of the tread portion in the tire width direction protrudes outward in the tire radial direction within a range of 30% to 70% of the width dimension of the belt disposed inside the tread portion in the tire radial direction. Heavy-duty radial tire for type vehicles.