JPH03260493A - 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 from a plurality of rings held at a certain spacing with the aid of retainers. 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. The insert 2 consists of a plurality of rings 3 held at a certain spacing with the aid of retainers 4. 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 fields] 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. 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 1,
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. 6, 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 tightly by reducing the diameter of the pipe 20 and pressing the insert 21 against the pipe to be connected so that the annular protrusion 22 bites into the outer surface of the pipe to be connected.

[Question 8 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.

Additionally, 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 have an annular protrusion that bites into the pipe to be connected to create a seal. However, if the connected pipe is deformed and the amount of tightening is small, 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 the Problems] The pipe joint of the present invention uses a cylindrical member made of a shape memory alloy as a driver, and presses an insert interposed between the driver and the pipe to be connected to the pipe to be connected. A pipe joint for connecting pipes, characterized in that the insert is a ring member consisting of a plurality of rings held by retainers at intervals between the rings, or the insert is a coil member with closed rings at both ends. It is something.

Further, the outer peripheral surface of the ring of the ring member or the closed ring of the coil member is lined with a metal or resin having a melting point lower than that of the tube material and the joint material.

[Operation] By pressing each ring of the insert composed of a plurality of rings against the pipe to be connected using a cylindrical member made of a shape memory alloy as a driver, the pipe to be connected is deformed by the ring, and the ring is attached to the pipe. It is possible to achieve sealing performance by making metal touch, and also to obtain sufficient tightening amount to prevent pull-out.

Further, when the insert is a coil member having closed rings at both ends, pulling out is prevented in the same manner as described above, and sealing performance is ensured by the closed rings at both ends.

Further, the sealing performance can be further improved by softening and solidifying the low melting point metal or resin lining the outer peripheral surface of the ring or the closed ring.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings in the case where stainless steel pipes are connected.

The cylindrical driver 1 is made of stainless steel (9Cr14Mn-5
It is a shape memory alloy of N 1-6S i-remaining Fe. The insert 2 is also made of stainless steel, and the spacing between the rings 3 is maintained by interposing a retainer 4 between the rings 3. Further, the outer peripheral surface of the ring 3 is lined with a low melting point metal or resin 8.

If the wall thickness of the connected pipe 10 is t, then the ring 3
The diameter of the driver 1 is 1 to 3 t, and the thickness of the driver 1 is 2 to 5 t.

The 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 ring 3 is attached to the connected pipe 1.
It is compressed so as to bite into the outer peripheral surface of 0. In this way, as shown in FIG. 1, the outer circumferential surface of the connected tube 10 is deformed, thereby preventing it from being pulled out. Moreover, by making metal contact with the inner surface of the ring 3, a seal is achieved, and the sealing performance is further improved by softening and solidifying the low-melting metal or resin.

Note that the cross-sectional shape of the ring is not limited to the circular shape as in the above embodiment, but may be a ring 3a having a rectangular cross-section as shown in FIG. In this case, the inner peripheral edge of the ring comes into metal contact with the connected pipe 10, and the outer peripheral edge of the ring partially bites into the inner peripheral surface of the driver 1, causing the surface finish of the inner surface of the driver 1 to deteriorate. It can be made unnecessary.

In addition, the insert has a coil material 6 as shown in FIG.
The coil member 5 may have closed rings 7 at both ends.

A low melting point metal or resin 8 is provided on the outer peripheral surface of the closed ring 7.
is lined.

In this case as well, in the same manner as described above, pulling out is prevented and sealing performance is ensured by the closing rings 7 at both ends.

In addition, 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 is explained. 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 cross-sectional view showing an example of the pipe joint of the present invention in use, Fig. 2 is an explanatory view showing an example of the insert, and Fig. 3 is a half cross-sectional view when using an insert of another shape. FIG. 4 is an explanatory diagram of another insert, FIG. 5 is a sectional view of a conventional shape memory alloy joint, and FIG. 6 is a sectional view showing a pipe joint in use when a shape memory alloy is used as a driver. 1... Cylindrical driver 2... Suit 3... Ring 4... Retainer insert 6... Coil material low melting point metal or resin. ...closed phosphorus

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 inserted between the driver and the pipe to be connected, the insert is formed into a plurality of rings, the intervals of which are held by a retainer. A pipe joint characterized by: 2) The pipe fitting according to claim 1, wherein the outer peripheral surface of the ring of the ring member is lined with a metal or resin having a melting point lower than that of the pipe material and the fitting material. 3) The pipe joint according to claim 1, wherein the insert is a coil member with closed rings at both ends. 4) The pipe fitting according to claim 3, wherein the outer peripheral surface of the closed ring of the coil member is lined with a metal or resin having a melting point lower than that of the pipe material and the fitting material.