JP2966920B2 - Floating vehicle tires - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a levitation type vehicle tire used at the time of takeoff and landing of a levitation type vehicle which travels while levitating, for example, by the action of magnetism.

(Prior art)

At present, a levitation type vehicle (hereinafter, referred to as a linear motor car) which floats and travels by the action of magnetism has been developed.
This linear motor car supports, guides, and propells the vehicle by the magnetic force that acts between the ground coil installed on the guideway and the superconducting magnet mounted on the vehicle, making the vehicle non-contact along the guideway It can be run in the state of. In theory, the flying height may be around a few millimeters, but in consideration of the characteristics of Japan, which is an earthquake-prone country, a strong magnetic field is created using a superconducting magnet to achieve a flying height of around 100 mm. I have.

By the way, in such a linear motor car, the vehicle floats on the road surface from the stop to the time when the vehicle floats up from the stop and until the vehicle lands on the road surface and stops, unlike the case of levitating and running up from the road surface due to magnetic force. Tires are equipped because they need to be mechanically supported and guided. While the tire for this linear motor car is under the full load of the linear motor car when stopped, the magnetic levitation force increases as the vehicle starts running and the speed increases, so the load applied to the tire gradually decreases. However, there is no load after takeoff. On the other hand, at the time of landing, contrary to the above-described takeoff, a load is gradually applied from a no-load state as the speed decreases, and after the stop, the linear motor car receives the full load.
Thus, the point where the load changes with time is not found in a tire applied to a normal automobile. For this reason,
Tires for linear motor cars have been developed.

By the way, since a linear motor car uses an electric brake (brake using magnetic force) for deceleration stop during normal driving, it is different from a tire applied to an automobile or the like which stops by a frictional force between a tire and a road surface, Less friction is required. For this reason, the tire for linear motor cars has a smooth surface with no grooves on the tread surface.

However, when such a linear motor car cannot stop or decelerate with the electric brake,
You must stop and slow down with the wheel brakes.
However, with such linear motor car tires, there is no groove on the tread surface, and when landing on a wet road surface from an ultra-high speed (for example, 550 km / h), the hydro-planing phenomenon causes friction between the tire and the road surface. It has been found by the inventor that the coefficient becomes extremely small and it becomes difficult to secure a stopping distance.

With reference to FIG. 4, a description will be given of a load change and a ground contact surface shape at the time of landing of a linear motor car to which a conventional dedicated tire for a linear motor car is applied. In FIG. 4, width A indicates the contact width at the time of 100% load, and width E indicates 100%.
% Load (at the end of hydroplaning phenomenon)
Is shown.

As shown in FIG. 4, immediately before the start of landing on a wet road surface, the load applied to the tire is zero, but at the time of landing, the value is obtained by subtracting the magnetic levitation force at the landing speed from the vehicle weight.
That is, when the linear motor car decelerates, the magnetic levitation force decreases, and the load applied to the tire dedicated to the linear motor car increases accordingly. When the linear motor car is completely stopped with further deceleration, the load at the time of stopping the vehicle (vehicle weight, that is, 100% load) is applied to the tire for the linear motor car. Here, in the initial stage of the landing of the linear motor car, the tire for the linear motor car is in contact with the tire from the center in the tire width direction.
The hydroplaning phenomenon occurs up to 35 to 45% (dimension E) of the contact width (dimension A) at 0% load,
After that, it became clear that the hydroplaning phenomenon did not occur.

[Problems to be solved by the invention]

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a floating vehicle tire that is unlikely to cause a hydroplaning phenomenon even when a linear motor car lands on a wet road surface in an ultra-high-speed running state.

[Means for solving the problem]

According to the invention of claim (1), no load is received in the takeoff state, and in the landing stop state, the tread abuts on the road surface, and 100%.
In the case of a floating vehicle tire that supports the load and touches from the center of the tread when a 100% load is applied at the start of landing, the tread width of the tread width centered on the center of the tread width at the 100% load At least one groove in the circumferential direction of the floating vehicle tire is provided in the tread within a dimension range of 45% in the direction, and the tread is worn from the time of new article until the remaining groove depth reaches 1.6 mm. Apparent contact area at 100% load between the tires (apparent contact area is 100%
When the load is applied, the ratio of the opening area of the groove on the contact surface to the contact area of the tire including the groove portion of the contact portion of the tire is 0.02 to 0.15 (when the apparent contact area is 1). ).

According to the invention of claim (2), the deepest part of the groove is 1.
An end wear display means is provided at a position 6 mm shallower and is exposed on the surface of the tread when the tread wears to indicate the end of wear.

[Action]

According to the invention described in claim (1), the contact width in the contact width direction is 45% of the contact width at the center of the contact width at a load of 100%.
At least one groove along the circumferential direction of the floating vehicle tire is provided in the tread within the size range of 100 mm, and a 100% load is applied until the tread wears from the time of new and the remaining groove depth reaches 1.6 mm. , The ratio of the opening area of the groove in the ground plane to the apparent ground area in the range of 0.02 to 0.15. Therefore, when a floating vehicle in an ultra-high speed running state lands on a wet road surface, this groove ensures that water between the tires for the floating type vehicle and the road surface will be used until the remaining groove depth reaches 1.6 mm. Drained.

According to the invention described in claim (2), 1.
Since the wear end indicator is provided at a position 6 mm shallower, when the tread wears and the end of wear of the floating vehicle tire is reached, the wear end indicator is exposed on the surface of the tread and the end of wear (tire Lifetime) is displayed, so that it is possible to visually recognize the time to replace the floating vehicle tire. Furthermore, when the end of wear is displayed, the groove is still
Since the 1.6 mm remains, the water between the floating vehicle tire and the road surface is reliably drained by the groove even at the end of wear.

〔Example〕

FIG. 2 shows a floating vehicle tire to which the present invention is applied.
A linear motor car 10 equipped with 14 is shown. The linear motor car 10 is supported on a guideway 12 via a floating vehicle tire 14. The guideway 12 has side walls 16, 18 corresponding to both side surfaces of the linear motor car 10, respectively.
Is erected. A guide tire 20 having a rotation axis perpendicular to the road surface is attached to a side surface of the linear motor car 10, and the guide tire 20 is in contact with the side walls 16 and 18.

On the surface of the guideway 12, a levitation coil 22 is laid, and a superconducting magnet installed in the linear motor car 10
The linear motor car 10 itself can be lifted about 100 mm with respect to the guide path 12 by a magnetic force acting between the linear motor car 10 and the guide path 12. The side walls 16 and 18 have a propulsion guide coil 26
Is attached, and the linear motor car 10 is propelled by a magnetic force acting between the superconducting magnet 24 installed on the linear motor car 10.

The floating of the linear motor car 10 is performed in a state where the speed reaches a predetermined speed. When the speed is lower than the predetermined speed, the linear motor car 10 is
Has come to support. Further, when the landing of the linear motor car 10 is stopped, the entire load (100% load, hereinafter referred to as 100% load) of the linear motor car 10 is applied to the floating vehicle tire 14. Also, this 100
% Load is the maximum load applied to the floating vehicle tire 14. As described above, the levitated vehicle tire 14 has a role as a support required for running and stopping before takeoff and after landing. Note that, during the levitating run, the levitated vehicle tire 14 is housed in a housing part (not shown).

As shown in FIG. 1 (A), the shape of the floating vehicle tire 14 is such that a carcass wound around a bead wire 28 formed in a ring shape around the tire rotation axis at both longitudinal ends.
30 is covered with a rubber layer 32, and a portion of the rubber layer 32 that contacts the road surface has a thick tread.
It is 34. A belt layer 36 is buried near the carcass 30 inside the tread 34 so as to reinforce the tread 34.

In the levitated vehicle tire 14 thus configured, a pair of grooves 38 are formed on the outer peripheral surface of the tread 34 at regular intervals in the tire circumferential direction.

As shown in FIGS. 1A and 1B, the pair of grooves
38 is along the tire circumferential direction (arrow S direction) within a range (dimension B) of 45% of the contact width direction (arrow W direction) centered on the center of the ground contact width (dimension A) at 100% load. Are located.

The shape of the groove 38 in a plan view is a straight line, and the cross section perpendicular to the longitudinal direction is formed in a substantially U-shape in which the width on the opening side is gradually wider than the width on the bottom. Furthermore, these grooves 38 wear the outer peripheral surface of the tread 34 from the time of new, and the remaining depth is 1.6 mm.
Until the above, the ratio of the opening area of the groove 38 in the ground to the apparent ground area at the 100% load is in the range of 0.02 to 0.15.

On the other hand, an organic fiber layer 40 as an end-of-wear display means is embedded inside the tread 34. The depth (dimension C) of the organic fiber layer 40 is 1.6 mm with respect to the depth (dimension D) of the groove 38.
It is buried in a shallow position, and when the tread 34 wears down and reaches a residual groove depth of 1.6 mm, the organic fiber layer 4 is formed on the surface of the tread 34.
0 is exposed.

 Next, the operation of the present embodiment will be described.

When the linear motor car 10 takes off, the load applied to the levitated vehicle tire 14 at the start of takeoff is the load when the vehicle stops (vehicle weight, that is, 100% load).
Linear motor car 10 has superconducting magnet 24 and propulsion guide coil
When the vehicle starts running by the magnetic force (propulsion) acting between the superconducting magnet 24 and the magnetic force (magnetic levitation force) acting between the superconducting magnet 24 and the levitation coil 22, the linear motor car 10 is supported. Therefore, the load applied to the levitated vehicle tie 14 gradually decreases. Further, when the vehicle speed reaches a predetermined speed at which sufficient levitation force to support the vehicle weight can be obtained by lifting the vehicle speed, the levitation type vehicle tire 14 is lifted, so that the load becomes zero, and finally the linear motor car 10 has only the magnetic levitation force. As a result, the vehicle can take off from the surface of the guideway 12 and run at high speed.

Next, changes in the load applied to the floating vehicle tire 14 when the linear motor car 10 lands and the shape of the ground contact surface with the road surface will be described.

As shown in FIG. 4, at the start of landing (t = 0), the load is zero, but at the time of landing, the magnetic levitation force at the landing speed is subtracted from the vehicle weight.

That is, when the linear motor car 10 is decelerated, the magnetic levitation force decreases, and the load applied to the levitation vehicle tire 14 increases accordingly. When the linear motor car 10 is further stopped with further deceleration, the levitation type vehicle tire 14 applies a load (vehicle weight, that is, a vehicle weight) when the vehicle stops.
100% load) is applied. Thus linear motor car 1
In the case of 0, by landing while gradually increasing the load, the occupant can land smoothly without impact.

Here, in the initial stage when the linear motor car 10 in an ultra-high speed running state (for example, 550 km / h) lands on the road surface, the floating vehicle tire 14 is in contact with the ground from the center in the contact width direction. Even if it is wet, even in the area where the conventional tire has a hydroplaning phenomenon because there is no groove in the center portion in the contact width direction, the water between the levitating vehicle tire 14 and the road surface Is drained from the groove 38, and the occurrence of the hydroplaning phenomenon can be prevented.
Furthermore, the tread 34 wears more than when it is new, and the remaining groove depth is 1.
For an apparent contact area at 100% load up to 6 mm, the opening area of the groove in the contact surface is 0.02 to 0.15.
So that when the tread 34 comes into contact with the road surface during landing, there is little shear deformation of the tread 34 surface,
Does not reduce wear resistance.

On the other hand, when the tread 34 wears due to long-term use of the floating vehicle tire 14 and the remaining groove depth reaches 1.6 mm,
The organic fiber layer 40 is exposed on the surface of the tread 34. Therefore, by visually checking the presence or absence of the organic fiber layer 40 on the surface of the tread 34, it is possible to know whether the floating vehicle tire 14 has reached the end of wear (tire life).

Furthermore, at this point, the groove 38 still remains 1.6 mm,
Even in the last stage of such wear, the water between the floating vehicle tire and the road surface is reliably drained by the groove 38, and the occurrence of the hydroplaning phenomenon can be prevented.

(Example) The water depth of the road surface was changed in each of the examples, the examples, the examples, the comparative examples, the comparative examples, the comparative examples, and the conventional examples of the floating-type vehicle tires prototyped with the specifications shown in Table 1. The presence or absence of the hydroplaning phenomenon,
Table 1 shows the measurement results of the braking distance index (the target braking distance is 100) when landing from a 550 km / h running state.

Next, the item columns (A) to (H) in Table 1 will be described.

(A): The number (grooves) of grooves within a dimension range of 45% of the contact width in the contact width direction with respect to the center of the contact width under a 100% load.

(B): Ratio of the groove area within the dimension range of 45% in the contact width direction with the remaining groove of 1.6 mm to the contact area at the time of 100% load.

(C): Ratio of the groove area outside the dimension range of 45% in the contact width direction at 1.6 mm of the remaining groove to the contact area under a 100% load.

(D): The water depth of the road surface is 0.25 mm (tire residual groove 1.6 mm).

(E): Water depth of road surface 1.0 mm (tire residual groove 1.6 mm).

(F): Depth of the road surface 3.0 mm (tire residual groove 1.6 mm).

(G): Whether or not the hydroplaning phenomenon has occurred when traveling at 550 km / h (on a wet road surface).

(H): Braking distance index when landing on a wet road surface from 550 km / h running (index when target braking distance is 100).

(I): Wear life index (85 for the target life of one year)
Above).

FIG. 3 is a graph showing the range in which the hydroplaning phenomenon occurs due to the change in the depth of the road surface and the ratio of the groove area in each of the examples of the examples, the examples and the examples shown in Table 1. FIG.

As is clear from the measurement results shown in Table 1 and FIG. 3, the floating type vehicle tire 14 according to the embodiment of the present invention is excellent in that the hydroplaning phenomenon is extremely unlikely to occur as compared with other tires. It is clear that

In the present embodiment, the groove is set within a range of 45% in the contact width direction around the center of the contact width at a 100% load.
38 is provided as a pair, but not limited to this, the groove is 100%
45 in the contact width direction centered on the middle part of the contact width under load
%, At least one groove may be provided along the tire circumferential direction, and the number of grooves may be one or three.

In the present embodiment, the groove 38 has a linear shape along the tire circumferential direction, but is not limited to this, and may be a zigzag-shaped groove.

Further, in this embodiment, the organic fiber layer 40 is provided at a position 1.6 mm shallower than the deepest portion of the groove 38 inside the tread 34 in order to indicate the end of tire wear, but the present invention is not limited to this. In addition, a slip sign that is 1.6 mm high at the bottom of the groove 38 as a means of indicating the end of wear, so that when the remaining groove depth becomes 1.6 mm, the groove 38 in that part is seen to be cut off May be provided.

〔The invention's effect〕

As described above, the floating vehicle tire according to the present invention has an excellent effect that the hydroplaning phenomenon is less likely to occur even when the linear motor car lands on a wet road surface in an ultra-high speed running state.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a levitated vehicle tire according to an embodiment of the present invention, which is taken through a tire rotation axis (however, hatching of a rubber layer is omitted), and FIG. FIG. 2 (A) is an explanatory view showing a ground contact shape of the floating vehicle tire at 100% load, FIG. 2 is a front view of a linear motor car,
FIG. 3 is an explanatory diagram showing in which range the hydroplaning phenomenon occurs due to a change in the depth of the road surface and the ratio of the groove area when the floating vehicle tire according to the embodiment of the present invention lands, FIG. 4 is an explanatory diagram showing the load applied to the floating vehicle tire when the linear motor car lands, the traveling speed of the linear motor car, and the contact shape at each load. 14 ... Floating type vehicle tire, 34 ... Tread, 38 ... Groove, 40 ... Organic fiber layer (end-of-wear indication means).

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60C 11/04 B60C 11/06 B60C 11/24

Claims (2)

(57) [Claims] 1. A load is not received in a takeoff state, and in a landing stop state, a tread abuts on a road surface to support a 100% load, and at the start of landing, a ground contact is made from the center of the tread surface when a 100% load is applied. In the levitated vehicle tire, a groove along the circumferential direction of the levitated vehicle tire is formed on the tread within a dimension range of 45% of the contact width in the contact width direction around the center of the contact width at 100% load. At least one
This is provided, and the tread wears more than when it is new and the apparent contact area at 100% load until the residual groove depth reaches 1.6 mm (apparent contact area is when a 100% load is applied to the tire. The ratio of the opening area of the groove in the ground contact surface to the entire area including the groove portion of the ground contact portion of the tire in (1) is in the range of 0.02 to 0.15. 2. A wear end display means which is provided at a position 1.6 mm shallower than the deepest portion of the groove and which is exposed on the surface of the tread when the tread wears and displays the end of wear. The levitation type vehicle tire according to claim 1, wherein: