JPH03260492A - Pipe fitting - Google Patents

Abstract

PURPOSE:To connect two pipes together having a relatively small wall thickness by using a cylindrical driver made of shape memory alloy and an insert interposed between this driver and two pipes to be joined, constituting a pipe fitting which accomplishes connection of pipes by means of pressing of these driver and insert, therein embodying the insert in the form of a corrugated pipe, and providing a metal having a low melting point. CONSTITUTION:An insert 2 in the form of corrugated pipe made of stainless steel etc. is fitted in a cylindrical driver 1 made of a shape memory alloy in stainless steel series, and pipes to be joined 10 are inserted from the two sides of this insert 2. At the inside of this insert 2, a metal 3 is provided which has a lower melting point than the materials to the pipe joined 10, driver 1, and insert 2. The driver 1 is dia. contracted by heating, and the pipes 10 are squeezed from the periphery by the insert 2. Thus the pipes 10 are deformed, which generates a resistant force working against being drawn out, and also seal is provided by the insert 2. As a result, the wall thickness of the driver made of shape memory alloy can be lessened, and the cost be suppressed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a pipe joint.

[Prior Art] As a pipe joint made of a shape memory alloy, there is one shown in FIG. 4. This is constructed by providing a plurality of annular protrusions 12 on the inner tightening surface of a cylindrical joint 11. Then, insert the pipe ends of the pipe 10 to be connected from both ends of this joint 11,
By raising the temperature of the joint 11 above the transition temperature, the diameter of the joint is reduced and the annular protrusion 12 bites into the outer surface of the pipes to be connected, thereby connecting the pipes 10 in a fluid-tight manner.

Further, as shown in FIG. 5, an insert 21 having a plurality of annular protrusions 22 formed on the inner surface is interposed between the cylindrical member 20 made of a shape memory alloy and the connected pipe 10, and the cylindrical member There is a pipe joint that connects the pipes 10 in a liquid-tight manner by reducing the diameter of the pipe 20 and pressing the insert 21 against the pipe to be connected, thereby causing the annular protrusion 22 to bite into the outer surface of the pipe to be connected.

[Problems to be Solved] The conventional pipe joint described above requires machining to form the annular protrusion 12 with high precision on the inner surface of the pipe joint 11.

Furthermore, it is necessary to increase the thickness of the shape memory alloy material in order to process the protrusions.

Furthermore, the insert 21 also requires machining to form protrusions.

In addition, conventional pipe fittings take into account the connection of thick-walled pipes, and the annular protrusion bites into the pipe to be connected to create a seal. However, when the wall of the pipe to be connected is relatively thin, If the amount of tightening is small, the connected pipe may be deformed, and sufficient sealing performance may not be obtained.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pipe joint suitable for connecting relatively thin-walled pipes.

Means for Solving Problem C] The pipe joint of the present invention acts as a driver for a cylindrical member made of a shape memory alloy, and presses an insert interposed between the dry nozzle and the pipe to be connected to the pipe to be connected. In the pipe joint for connecting pipes, the insert is a corrugated pipe, and a metal or resin having a melting point lower than that of the pipe material and the joint material is provided on the contact surface of the corrugated pipe with the pipe to be connected. It is something to do.

[Operation] By pressing the corrugated pipe insert against the pipe to be connected using a shape memory, cylindrical member made of 6 gold as a driver, the corrugated part of the corrugated pipe deforms the pipe to be connected and provides pull-out resistance. .

In addition, the corrugated portion is brought into metal contact with the tube to obtain sealing performance, and the sealing performance is further improved by softening and assimilation of the low melting point metal or resin provided on the contact surface.

C Embodiment One embodiment of the present invention will be described below with reference to the drawings in the case where stainless steel pipes are connected.

The cylindrical driver 1 is made of stainless steel (9Cr-14Mn-
It is a shape memory alloy of 5Nj-6S i-remaining Fe), and the heating temperature for diameter reduction is 300 to 350°C. The corrugated pipe insert 2 is also made of stainless steel.

When the wall thickness of the connected pipe 10 is t, the wall thickness of the corrugated pipe 2 is 1 to 3 t, and the thickness of the driver 1 is 2 to 5 t.
It has become t.

The corrugated pipe insert 2 is attached to the cylindrical member 1 as a driver, and the pipe to be connected 10 is inserted from both sides. Then, by heating and reducing the diameter of the driver 1, the corrugated pipe 2 tightens the connected pipe 10 from the outer periphery. thus,
As shown in FIG. 1, the outer peripheral surface of the connected pipe 10 is deformed,
Provides pull-out resistance. Moreover, by touching the bottom corrugated part of the corrugated pipe 2 with the metal, a seal is formed, and the sealing performance is further improved by softening and solidifying the melting point metal.

Furthermore, even if a thermoplastic resin is used instead of a low melting point metal,
A similar effect can be obtained.

Furthermore, in the above embodiment, the case where the insert is provided outside the pipe to be connected and the diameter of the driver is reduced to connect the pipe has been described. It can also be applied when connecting.

[Effects of the Invention] The pipe joint of the present invention is as described above, and the wall thickness of the shape memory alloy material can be made thinner than in the past, thereby reducing material costs. Further, since the conventional machining process for forming the annular protrusion is not required, manufacturing costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is a half sectional view showing an example of the pipe joint of the present invention in use, Figs. 2 and 3 are explanatory views showing the state in which a low melting point metal is attached to the insert, and Fig. 4 is a conventional one. FIG. 5 is a sectional view showing a pipe joint in use when a shape memory alloy is used as a driver. 1... Cylindrical driver 2... Corrugated pipe insert 3... Low melting point metal.

Claims (1)

[Claims] 1) A cylindrical member made of a shape memory alloy as a driver,
In a pipe joint that connects pipes by pressing an insert interposed between the driver and the pipe to be connected to the pipe to be connected, the insert is a corrugated pipe, and
A pipe joint characterized in that a metal having a melting point lower than that of the pipe material and the joint material is provided on the contact surface of the corrugated pipe with the pipe to be connected. 2) The pipe joint according to claim 1, wherein a resin having a melting point lower than that of the pipe material and the joint material is provided on the contact surface of the corrugated pipe with the connected pipe.