JPH08178140A - Shape memory alloy joint - Google Patents

Abstract

PURPOSE: To perform stable connection of a piping by means of a shape memory alloy joint wherein piping connection for an air-conditioning apparatus and hot water feeding and cold water feeding device is effected by utilizing a shape memory alloy. CONSTITUTION: A shape memory alloy joint 1 comprises a pipe joint 1b made of a shape memory alloy molded in a cylindrical shape; a cylindrical liner 1a laminated in the inside of the pipe joint; a protrusion 1d, formed on the periphery of the central part of the inner surface of the liner 1a; and an adhesive-coated layer 1c formed on the inner surface of the liner 1a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape memory alloy joint for connecting pipes of an air conditioner, a hot water supply system, etc. by using a shape memory alloy.

[0002]

2. Description of the Related Art Conventionally, a pipe connection structure using a shape memory alloy has been disclosed in, for example, "Investigation Research Report II on Application Development of Shape Memory Alloys" issued by the Osaka Chemical Technology Center in March 1984. , Pp. 61-63, as shown in FIG.

That is, after inserting the pipe (102) from both sides of the shape memory alloy joint (101), the shape memory alloy joint (1
01) is heated and connected. In such a configuration, both pipes (10
2) The end needs to be located in the center of the shape memory alloy joint (101).

[0004] However, in practice, whether the one or the other of the tube because it does not know that both sides are located in the center (10
An insertion allowance mark (103) was appropriately placed on the surface of 2) with a writing instrument or the like.

[0005]

However, in the conventional connection method utilizing the heat shrinkage of the shape memory alloy joint (101), since there is a gap between the pipe (102) and the liner (104), the mark ( When the shape memory alloy joint (101) is contracted by a method such as attaching a pipe (10),
2) or the shape memory alloy joint (101) moves,
As shown in FIG. 2, the end surface of the pipe (102) was displaced from the center of the shape memory alloy joint (101), and there was a possibility that the tensile strength was lowered, gas leaked, and the like.

For this reason, when heat-shrinking so as not to shift the position, it is necessary to heat with caution, and there is a problem that workability is poor.

Therefore, the present invention is intended to prevent positional deviation and to obtain a reliable connection.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a projection on all or part of the circumference of the central portion of the inner surface of the liner of a shape memory alloy joint, so that the pipe is inserted when the pipe is inserted. The end surface of the liner abuts on the projection of the liner, and the inner surface of the liner is coated with an adhesive so that the liner can be more firmly fixed.

[0009]

The function of the above means is that when the pipes are connected, both pipes can be positioned and there is no need to write a positioning mark.

When heat-shrinking the shape memory alloy joint, the displacement can be prevented by pressing the pipe against the projection.

[0011]

EXAMPLE An example of the present invention will be described.

The liner (1a) of the shape memory alloy joint (1) shown in FIG. 1 has a protrusion on the whole or part of the circumference of the center of the inner surface, and the inner surface of the liner (1a) has a projection. Adhesive (1b) is coated.

The shape memory alloy joint (1) is a pipe joint (1c) made of a cylindrical shape memory alloy, a cylindrical liner (1a) inserted inside the pipe joint (1c), and an inner surface of the liner (1a). Protrusions (1
d) and the adhesive (1) formed on the inner surface of the liner (1a)
It is composed of the coating layer of b).

In the above structure, the pipes are connected by connecting the pipes (2) and (3) to the liner (1) from both of the shape memory alloy joints (1).
The pipe joint (1c) is inserted until it hits the protrusion (1b) of a) and the pipe joint (1c) is heated in this state,
It contracts due to its shape change property, and tightly clamps the tubes (2) and (3) via the liner (1a).

Therefore, since the pipes (2) and (3) are clamped and fixed by the shape memory alloy joint (1) with the same insertion dimension, the pipes are stably fixed. Moreover, the liner (1a) and the inserted pipes (2) and (3) are firmly adhered by the adhesive (1b) formed on the inner surface of the liner (1a), and there is no fear of gas leakage.

[0016]

As described above, according to the present invention, the protrusion is provided on the circumference of the central portion of the inner surface of the liner of the shape memory alloy joint device,
At the time of pipe connection, the end surface of the pipe can be kept in the center of the shape memory alloy joint device, and stable connection can be achieved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a connected state of a shape memory alloy joint in one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a connected state of a conventional shape memory alloy joint.

FIG. 3 is a side view showing a disassembled state of the same shape memory alloy joint.

[Explanation of symbols]

 1 Shape Memory Alloy Joint 1a Liner 1b Adhesive 1c Pipe Joint 1d Protrusion 2 Pipe 3 Pipe

Claims (1)

[Claims] 1. A shape memory alloy joint in which a protrusion is provided on the circumference of the central portion of the inner surface of the liner in a cylindrical liner inserted into a pipe joint formed by processing a shape memory alloy material into a cylindrical shape.