JPH0882396A - Heat insulation support device - Google Patents

Abstract

PURPOSE: To provide a heat insulation support device which is constituted to reinforce load resistance while excellent heat insulating property is maintained. CONSTITUTION: A helical winding 4 is axially applied on a thin cylinder part 3, and further a hoop winding 5 is applied on an innermost layer and an outermost layer. Further, the end part 1 and the central part 2 of the thin cylinder part 3 are increased in thickness by applying the hoop winding 5 thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adiabatic support device having enhanced load resistance.

[0002]

2. Description of the Related Art In a magnetically levitated train having a superconducting magnet, the superconducting magnet serves as a motor for running and stopping the train. Such a superconducting magnet is stored in a vacuum container in order to keep it in a cryogenic state, and a load supporting structure for supporting the superconducting magnet is required in the vacuum container. Liquid helium is generally used to keep the superconducting magnet in a cryogenic state. The temperature of liquid helium is approximately 4K, and the temperature of the external environment is 300K.
Then, a temperature difference of 296K occurs. The maximum amount of heat transfer between liquid helium temperature and room temperature is
This is the load supporting structure. Therefore, how to support the superconducting magnet while insulating it and to reduce the amount of liquid helium used is an important point for practical use of the superconducting magnet.

The load-bearing structure generally has a fiber reinforced plastic (hereinafter, FRP) having low thermal conductivity and high specific strength.
Say. ) Is used as a heat insulating support material. A conventional example of a heat insulating support material for a superconducting magnet using this type of FRP is shown in FIG.

In the same figure, the heat insulating support material has a thin hollow cylindrical shape in order to improve heat insulating properties. Most of the force applied to the heat insulating support member is in the axial direction, and the problem is that the force in the compression direction is applied. In an example of the heat insulating support material, in consideration of bending in the direction perpendicular to the axial direction, the end portion of the cylindrical portion is increased in thickness for reinforcement, and the cylindrical portion is wound by helical winding by a filament winding method. Although glass reinforcing fibers, carbon fibers, and the like are mainly used as FRP fibers, alumina fibers having higher specific strength and high heat insulation properties may be used in some cases. Unlike glass fiber and carbon fiber, alumina fiber has a risk of being cut by friction during the production process when the fiber is cross-wound in the loading direction, so the mechanical strength will decrease, but helical winding will be performed by filament winding. Is going.

Generally, when a compressive load is applied to a thin-walled cylindrical shape, buckling rupture due to bending often occurs at a load level lower than the original compressive strength of the material. For this reason, it is necessary to consider an adiabatic support material that takes into consideration not only the yield point of the material but also the buckling strength of the material. The buckling mode during buckling of the conventional heat insulating support is 1, and the antinode of vibration is the central portion of the thin-walled cylinder. Therefore, the portion where the thin-walled cylindrical heat insulating support member buckles due to compression is the central portion of the cylinder where the displacement due to bending is the largest.

[0006]

In consideration of the heat insulating property, the hollow cylindrical heat insulating support material which is made thin has a buckling mode 1 buckling failure, and it just buckles at the center of the cylindrical portion. The buckling strength of a thin cylinder is proportional to the square of the wall thickness. Therefore, if the thickness of the cylindrical portion is reduced in order to maintain the heat insulating property, the buckling strength is significantly reduced. Further, the buckling load is inversely proportional to the square of the height of the heat insulating support material, and the buckling strength of the cylinder having a large ratio of the height to the radius is reduced. An object of the present invention is to provide a heat insulating support material having enhanced load resistance while maintaining good heat insulating properties.

[0007]

In order to achieve the above object, the present invention has a container in which a superconducting magnet is housed, a vacuum container provided outside the container, and a thicker central portion. Since the hollow cylindrical shape is provided with the fiber-reinforced plastic and is provided with the heat insulating support portion that holds the container in the vacuum container, the load resistance can be enhanced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the heat insulating support material of the present invention, which uses alumina reinforced fiber FRP and is + 20 ° with respect to the axial direction in the thin cylindrical portion 3 by the filament winding method.
A helical winding 4 is applied at -20 °. Hoove winding 5 is applied to the innermost layer and the outermost layer of the cylinder. In addition, the end portion 1 and the central portion 2 are subjected to hoof winding to increase the wall thickness and finish the surface by machining, and the increase in the surface area of the heat insulating support material due to the increase in the wall thickness is about 3%.

A cross-winding method in which fibers are assembled in the direction of load application is effective as a method for laminating FRP, but alumina fibers are characterized by higher specific strength and lower thermal conductivity than glass fibers and carbon fibers. On the other hand, if the fibers are cross-hatched with each other, the fibers may be cut due to friction between the fibers in the manufacturing process. Therefore, helical winding is performed by filament winding.

The conventional heat insulating support member shown in FIG. 5 is provided with hoof winding only at the end portions thereof, and when a compressive load is applied, it is buckled substantially in buckling mode 1 at the center portion of the heat insulating support member. Cause destruction. On the other hand, in the embodiment, since the thickness of the central portion of the heat insulating support member, which is the antinode of the buckling mode 1, is increased even if a compressive load is applied, buckling here hardly occurs, and the heat insulating support member is Buckling failure occurs in the area corresponding to the belly of buckling mode 2. While the amount of heat conduction is inversely proportional to the height of the heat insulating support material, the buckling strength is proportional to the square of the wall thickness, so the increase in buckling strength is sufficient for the rate of heat loss due to increasing the wall thickness. Shows a large value. This makes it possible to improve the buckling strength while maintaining good heat insulation by reducing the dimensions of the heat insulating support and adjusting the surface area and cross-sectional area of the support.

Here, FIG. 2 shows the results of buckling evaluation of the conventional heat insulating support material and the heat insulating support material in which the thickness of the central portion in this embodiment is increased. FIG. 2 (a) is a conventional one, (b)
In this embodiment, the heat insulating support rupture position is, as can be seen from FIG. 2B, a seat position ¼ of the height corresponding to the mode 2 antinode and the center of the mode 1 antinode. It gave me a bow. Further, it was confirmed that the buckling strength was improved by about 40% or more as compared with the conventional heat insulating support material.

As described above, it is understood that the product of this example has enhanced buckling strength while maintaining its heat insulating property as compared with the conventional product. FIG. 3 shows a second embodiment of the present invention in which a node plate is sandwiched in the center of the heat insulating support material. The heat insulating support material is divided into upper and lower parts, and the knot board 9 is sandwiched between the heat insulating support materials and bonded. The node plate 9 completely restrains the antinode portion of the vibration, and as a result, the buckling mode becomes the second
Switch to mode. As compared with the above-mentioned examples, it is possible to realize higher buckling strength and bending strength, the buckling fracture strength is stabilized, and the buckling strength is improved by 40 to 50%.

Next, FIG. 4 shows a third embodiment of the present invention, in which a cord is radially stretched inside the center of the heat insulating support material. The tension of the string prevents the center portion of the heat insulating support material from bulging outward due to the amplitude, and as a result, the buckling position is determined by the buckling second mode buckling without increasing the outer diameter of the cylinder central portion in the cylinder outer direction. It is possible to improve the buckling strength.

[0014]

As described above, according to the present invention, a container in which a superconducting magnet is stored, a vacuum container provided outside the container, and a hollow cylindrical fiber-reinforced plastic having a thick central portion are thickened. Since it is provided with a heat insulating support portion formed in the vacuum container for holding the container in the vacuum container, the load resistance can be enhanced while maintaining good heat insulating property.

[Brief description of drawings]

1A and 1B are views for explaining a first embodiment of a heat insulating support device of the present invention, in which FIG. 1A is a sectional view and FIG.

FIG. 2 is a comparative explanatory view of a buckling failure state between the heat insulating support device of FIG. 1 and a conventional device.

3A and 3B are views for explaining a second embodiment of the heat insulating support device of the present invention, FIG. 3A is a sectional view, and FIG.

FIG. 4 is a diagram for explaining a third embodiment of the heat insulating support device of the present invention.

5A and 5B are views for explaining a conventional heat insulating support device, in which FIG. 5A is a front view, FIG. 5B is a sectional view, and FIG.

[Explanation of symbols]

1 ... End part, 2 ... Central part, 3, 12, 13 ... Thin-walled cylindrical part,
9 ... Knot board, 10 ... Edge, 11 ... Adhesive surface, 14 ... String

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Nakao No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation Fuchu factory

Claims (4)

[Claims] 1. A container in which a superconducting magnet is stored, a vacuum container provided outside the container, and a hollow cylindrical fiber reinforced plastic having a thickened central portion formed of fiber-reinforced plastic. And a heat insulating support unit for holding the heat insulating support unit. 2. The adiabatic support part is divided into two cylinders with a central part being a plane perpendicular to the load support direction, and a nodal plate is sandwiched and adhered between the divided cylinders. The heat insulating support device according to claim 1, wherein the heat insulating support device is a heat insulating support device. 3. The heat insulating support device according to claim 1, wherein the heat insulating support portion has a central portion fixed from the inner side by a tension of a string stretched radially inward. 4. The heat insulating support device according to claim 1, wherein the fiber reinforced plastic is made of alumina fiber.