JPH0513391B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a heat insulating support rod that supports a space between a normal temperature section and a cryogenic section of a superconducting device.

[Technical background of the invention and its problems]

Regarding conventional heat insulation support rods, Figures 6 to 8
This will be explained with reference to the figures. This is based on the literature (Kawate et al., Research on Low Temperature Materials (1); Thermal and Mechanical Properties of Heat Insulating Support Materials; Low Temperature Engineering Vol.14 No.4 P164-177
(1977)).

In Figures 6 to 8, 1 is a rod;
Joint fittings 2 are fitted to both ends of the rod 1. The joint fitting 2 is made of non-magnetic metal and is composed of a half-split fitting 3, a cylindrical fitting 4, and a bolt 5. Rod 1
In this example, glass fibers 6 are impregnated with resin 7, bundled and pulled out through a heated nozzle to solidify, and then cut.The glass fibers 6 are arranged parallel to the central axis of the rod 1. Further, the central part of the rod 1 has a predetermined diameter A, a part of the end part has a diameter B, and the end face has a diameter C, and the size relationship of dimensions A, B, and C is set to be A≦B<C. Further, a tapered portion 8 having a slope of Y/X (Y=C-B/2) is provided between the diameters B and C. The glass fibers 6a arranged inside the diameter A are continuous to both ends of the rod 1, but the glass fibers 6b arranged outside the diameter A are cut into short pieces by cutting. The half-split metal fitting 3 has a cylindrical shape divided into two along a plane passing through the central axis, and its inner shape is similar to the tapered part 8 of the rod 1.
It matches. Further, the half-split fitting 3 is hooked onto the tapered portion 8 of the rod 1 to prevent the rod 1 from being pulled out from the joint fitting 2. Cylindrical metal fitting 4
It has a cylindrical shape with a protrusion 9 at one end and a screw hole 10a inside the other end, and the inner diameter of the middle part matches the outer diameter of the half-split metal fitting 3. Further, a half-split metal fitting 3 is held inside the cylindrical metal fitting 4, and an end face of the half-split metal fitting 3 is hooked onto the protrusion 9. Further, a screw 10b provided at the end of the bolt 5 is fastened to the screw hole 10a, and a half-split metal fitting 3 is fastened between the tip end surface 11 of the bolt 5 and the protrusion 9. The bolt 5 is provided with a second threaded portion 10c on the opposite side of the threaded portion 10b, which serves as an attachment portion for the heat insulating support rod.

The rod 1 of the conventional heat-insulating support rod constructed as described above undergoes shear failure at the portion between the core glass fiber 6a and the outer glass fiber 6b under a low tensile load.
There was a problem that the rod 1 could easily be pulled out from the fitting 2.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a heat insulating support rod that prevents shear failure of the portion between the core side and outer fibers and has excellent mechanical strength.

[Summary of the invention]

In the present invention, not only the tapered part is hooked on the half-split metal fitting, but also the slope Y/X of the tapered part 8 is set to 1/
10 or less, pull or push the rod in the direction of the central axis with a force greater than the support load and to the extent that it will not cause damage, press the tapered part of the rod into the half-split metal fitting, and then make sure that the tapered part returns from the half-split metal fitting. By pressing the tip of the bolt against the end of the rod and applying a compressive force in the radial direction between the core glass fiber and the outer glass fiber, the shear fracture strength between the two glass fibers is increased. make it higher.
And by setting the slope Y/X to 1/30 or more,
The clamping force acting in the radial direction of the tapered part of the rod is restricted, the tapered part is prevented from being gradually plastically deformed by the clamping force, and the rod is prevented from being gradually pulled out of the fitting 2 due to plastic deformation. This prevents the spacing between the joint fittings from changing over a long period of time.

[Embodiments of the invention]

Example 1 A first example of the present invention will be described below with reference to FIG. In FIG. 1, the same parts as those of the conventional example shown in FIGS. 6 to 8 are designated by the same reference numerals, and the explanation thereof will be omitted.

A rod 1 is manufactured by cutting a pultruded glass fiber-reinforced plastic rod so that the middle part has a small diameter and both ends are tapered outward with a slope Y/X of 1/30 to 1/10. Reference numeral 6 indicates glass fibers, including the core glass fiber 6a and the outer glass fiber 6.
b, and 7 is resin. The tapered part 8 is wrapped with a half-split metal fitting 3 having a taper hole that matches the tapered part 8 of the rod 1, and the half-split metal fitting 3 is held from the outside by a cylindrical metal fitting 4. A protrusion 9 is provided on the inner diameter of the inner end of this cylindrical metal fitting 4 to prevent the half-split metal fitting 3 from coming off, and a screw hole 10a is provided on the inner diameter of the outer end. Engagement screw 10b that engages with this screw hole 10a
Then, using a bolt 5 having a coupling screw 10c screwed to a fixed part (not shown), the tip end surface 11 of the rod is pressed in the direction of the central axis, that is, in the direction of the arrow M.
The half-split fitting 3, the cylindrical fitting 4, and the bolt 5 are collectively referred to as a joint fitting 2. The cylindrical metal fitting 4 is fixed to a fixing member (not shown), and the M
Press fit the tapered part into the half-split metal fitting 3 by pulling or pushing in the direction of the arrow. At this time, the rod tip 1
1 forms a protrusion 12 that protrudes from the end of the half-split metal fitting 3, leaving a gap 13, and sufficiently presses the rod tip 11 with the bolt 5 so that the tapered part 8 returns in the direction opposite to the arrow M. Make sure it doesn't come out. A parallel part 14 is provided on a part of the outer periphery of the cylindrical metal fitting 4, and when fastening the bolt 5 to the cylindrical metal fitting 4, a jig is attached to the parallel part 14 to prevent rotation of the cylindrical metal fitting 4. Also, when the tapered part 8 is press-fitted into the half-split metal fitting 3, the root part 15, which is the minimum diameter part of the tapered part,
The corners of the half-split metal fitting 3 that are in contact with the root part 15 are rounded so that stress is not concentrated on the edges. Furthermore, when press-fitting the tapered portion 8 into the half-split metal fitting 3, the protruding portion 12 is
The corner of the half-split metal fitting 3 that 2 hits is rounded.

Next, the effect will be explained.

The tapered part 8 is not only hooked on the half-split metal fitting 3, but also tightened in the radial direction by the half-split metal fitting 3, and the radial direction between the core side glass fiber 6a and the outside glass fiber 6b inside the tapered part 8 is Since the structure is configured such that a compressive force is applied to the core glass fibers 6a and the outer glass fibers 6b, the shear fracture strength of the portion between the core glass fibers 6a and the outer glass fibers 6b is high. In addition, since the tapered part 8 is held down by the bolt 5 so that it does not come out in the outward direction of the arrow M by the half-split metal fitting 3, the tightening force in the radial direction of the tapered part 8 is increased between the core glass fiber 6a and the outer glass fiber 6b. The compressive force between and the shear fracture strength are stable over a long period of time.

Next, the effects will be explained.

Figure 2 shows the relationship between the fracture strength and slope of the tapered part 8.
2 shows the relationship between the change in the interval between the joint fittings 2 and the slope when the joint fittings 2 at both ends are repeatedly pulled. Further, the solid line shows the result when the tapered part 8 is press-fitted into the half-split metal fitting 3, and the broken line shows the result when it is not press-fitted. As shown in this result, when press-fitting, if the slope is set to 1/10 or less, the breaking strength can be maintained at approximately 80% or more, and if the slope is set to 1/30 or more, the spacing between the fittings 2 will change. is found to be almost zero. This effect is particularly remarkable compared to the broken line curve in the case of no press fitting, indicating that it exhibits excellent performance as a heat insulating support rod.

Embodiment 2 In contrast to Embodiment 1, there may be a gap between the dividing surfaces of the half-split metal fittings 3a and 3b.

Even in this case, effects similar to those of the first embodiment can be obtained.

Example 3 FIG. 3 shows a heat insulating support rod manufactured in the third example. This relationship is made such that A<B, so that no radial tightening force is applied to the root portion 15 of the tapered portion. The rest is as in Example 1.

Even in this case, the same effects as in the first embodiment can be obtained.

Example 4 FIG. 4 shows a heat insulating support rod manufactured in the fourth example.

This is done so that the root portion 15 of the tapered portion is brought out of the half-split metal fitting 3, so that no radial tightening force is applied to the root portion 15. The rest is as in Example 1.

Even in this case, the same effects as in the first embodiment can be obtained.

Example 5 FIG. 5 shows a heat insulating support rod manufactured in the fifth example.

This connects the outside of the half-split metal fitting 3 and the inside joint surface of the cylindrical metal fitting 4 with a taper, and the half-split metal fittings 3a,
The small diameter side of the metal fitting 3b is placed outside the cylindrical metal fitting 4, and the root portion 15 on which the ends of the half-split metal fittings 3a and 3b come into contact is placed outside the cylindrical metal fitting 4. The rest is the same as in Example 1.

Even in this case, the tightening force acting in the radial direction of the root portion 15 can be reduced, and the same effects as in the first embodiment can be obtained.

In addition, the reinforcing fiber is not only glass, but also carbon fiber or Kevlar fiber (trade name of Dupont).
etc. may also be used.

〔Effect of the invention〕

As explained above, according to the present invention, both ends of the fiber-reinforced plastic rod are tapered outward, the slope of this taper is set to 1/30 to 1/10, and the tapered part is sandwiched between the half-split fittings 3. This was held with a cylindrical metal fitting, and the rod was pulled or pushed in the direction of the central axis with a force greater than the supporting load but not damaging the rod, and the tapered part was press-fitted into the half-split metal fitting. It stably increases the shear fracture strength of the portion between the core side fibers and the outside fibers of the tapered portion, making it possible to support a larger load than before. Also, if the supporting load is the same as before,
This has the advantage of reducing the cross-sectional area of the rod, increasing thermal resistance, and reducing the amount of heat intrusion. Furthermore, by setting the slope of the taper to 1/30 or more, the distance between the fittings fitted to both ends of the rod hardly changes, so when supporting between two points with this insulating support rod,
There is an advantage that the distance between the supporting points can be maintained stably.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a joint at one end of a heat insulating support rod manufactured by the method of the first embodiment of the present invention, and FIG. 2 is a curve diagram showing the characteristics of the first embodiment. Figures 3 to 5 are longitudinal sectional views showing the joints at one end of the heat insulation support rod manufactured by the methods of the third to fifth embodiments, and Figure 6 is the heat insulation manufactured by the conventional method. A vertical cross-sectional view showing the joint at one end of the support rod, Fig. 7 is an exploded perspective view showing the cylindrical fitting and rod in Fig. 6, and Fig. 8 is an exploded perspective view showing the half-split fitting and bolt in Fig. 6. It is a diagram. 1... Rod, 2... Joint fitting, 3... Half-split fitting, 4... Cylindrical fitting, 5... Bolt, 6... Fiber, 6a... Core side fiber, 6b... Outer fiber, 7...
...resin, 8...tapered part, 10a, 10b, 10
c...screw, 11...rod tip surface.

Claims (1)

[Claims] 1 A pultruded fiber-reinforced plastic rod is cut to make the middle part smaller in diameter, and both ends are tapered outward with a slope of 1/30 to 1/10, and the rod matches the taper of this rod. A half-split metal fitting with a tapered hole that holds the half-split metal fitting from the outside, a cylindrical metal fitting that has a threaded hole on the inner diameter of the outer end, and a cylindrical metal fitting that engages with the threaded hole of this cylindrical metal fitting, and the rod end surface is aligned with the central axis. The cylindrical metal fitting is fixed with a bolt arranged so as to be pressed in the direction, and the tapered part is split in half by pulling or pushing the rod in the direction of the central axis with a force greater than the supporting load but not damaging the rod. A method for manufacturing a heat insulating support rod, which is characterized by being press-fitted into a metal fitting.