JPS5986784A - Method of connecting pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of connecting shivives by plastic deformation using a joint.

Conventionally, this type of connection method includes, for example, Japanese Patent Publication No. 55-5987.
As shown in Japanese Patent No. 5, there is a joint connection method in which the circumferential surface of a certain zone within the joint diameter reduction range is plastically deformed into a polygonal cross-sectional shape without changing the circumferential length of the connecting knob. However, in the above prior art, as the number of sides of the polygon in the polygonal cross section of the plastically deformed portion decreases, for example, in the square shape shown in FIG.
- Since B is large, it has thrust resistance, but because of the rectangular shape with the same outer circumference as the pipe circumference before deformation, the pressure loss of the fluid increases due to the small cross-sectional area of the pipe. On the other hand, as the shape becomes a reverse side shape, for example, in the angle shape shown in Fig. 2, the distance from the circumferential surface of the pipe before deformation (C-I) is small, so the pressure loss decreases. It also had the drawbacks of poor torsion resistance due to the gentle barrier resistance along the outer circumferential surface of the knob after deformation.

The present invention provides a pipe connection method with excellent thrust resistance and torsional resistance without increasing fluid pressure loss.

The present invention provides at least one curve on the circumferential surface within the joint diameter reduction range toward the pipe axis, without plastically deforming the connecting pipe into a polygonal cross-sectional shape having the same length as the circumferential length of the connecting pipe, as in the prior art.
The protrusion may have a circular arc-shaped cross section, and the protrusion may be spherical or may have a length in the direction in which the fluid flows. Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 3, the inner diameter of the joint main body part 1 is formed smaller than the outer diameter of the vibro, and an annular groove part 6 is formed on the inner surface of the socket of the both side connecting parts 2. An airtight material 4 such as an O-ring is built into the annular groove 3. A pipe 6 is inserted into the connecting portion 2 of this joint F. The inner surface of the connecting part 2 of the joint F and the outer circumferential surface of the vibro are easily fitted and have a dimensional tolerance that creates a clearance C that can be absorbed by reducing the diameter of the connecting part 2, and the specified fitting of the connecting pipe is made. This interpolates the matching length. Accordingly, C uses a press mold 77 with a top and bottom split mold shape that compresses the connecting portion 2 with a hydraulic device or the like and has a desired shape of the mold surface, and compresses the connecting portion 2 from the outer peripheral surface as shown in Fig. 4. absorbs the clearance C and decreases, and the connecting portion 2 and the vibro are crimped together.

At the same time, the annular groove 3 is also pressurized, and the internal airtight material 4 is pressed against the outer peripheral surface of the connecting vibro, thereby maintaining the airtightness of the joint connection section.

Simultaneously with the above compression, a length Z5 in the fluid flow direction is applied to the inner surface of the press mold 7.7 within the diameter reduction range Z1 of the connection part.
At least one protrusion 7a formed in an arcuate cross-section with
, 7a in the radial direction, and the joint connection part 2
The pipe wall of the fitting part of the connecting vibro is plastically deformed together.

FIG. 5 shows a cross-sectional view of the connection state shown in FIG. 4 rotated by 90 degrees. In this case, the concave surfaces 7b of the connecting pipe on the inner surface of the connecting portion are carved at two locations on the circumference of the pipe.

It is.

FIG. 6 shows another embodiment of the invention, in which instead of a projection having a certain length in the fluid flow direction, at least one spherical projection 8a with an arcuate cross section is provided on the inner surface of the press die 8.8. ,8a
is formed, whereby the clamped joint connecting portion 2 and the pipe wall of the connecting vibro are plastically deformed together. FIG. 7 shows a sectional view obtained by rotating the connection state shown in FIG. 6 by 90 degrees. In this case as well, the concave surfaces 8b of the connecting pipe on the inner surface of the connecting portion are carved at two locations on the circumference of the pipe. In this way, the joint connection part and the connecting pipe are integrated into a machined concave surface 7b or 8b with an arc-shaped cross section.
Since the joint F is plastically deformed as shown in FIG. In this embodiment, the illustrated socket joint is shown, but it is of course applicable to elbows, tees, reducer joints, etc. Furthermore, the protrusion having an arcuate cross section is provided within the diameter reduction range Z1 of the connecting portion 2. Any position, any size, and any quantity can be selected depending on the application.

As described above, according to the present invention, by providing at least one protrusion having an arcuate cross section toward the pipe axis on the circumference within the joint connection range, the ttIT area is Compared to those that reduce the
It also has excellent effects and its industrial value is extremely large.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views of a pipe that has been deformed into a polygonal cross-sectional shape using the conventional method, and Figure 3 is a cross-sectional view of the pipe before installation with a socket joint trap pipe inserted.
Fig. 4 is a partial sectional view showing the state after construction where the joint connection part is crimped with a press mold, and Fig. i'A5 is a partial sectional view of the previous connection state viewed from a 90 degree different direction. , Fig. 6 is a partial sectional view showing the state after construction of the present invention (D) in which the joint connection part is crimped with a press die formed with spherical protrusions, and Fig. 7 is a 90 degree difference from the connection state in Fig. 6. Figure 8 is a partial cross-sectional view from the perspective of (directional force), Figure 3 is 1-1 Figure 7 Figure 1

Claims (1)

[Claims] t. The inner diameter of the joint body is smaller than the outer diameter of the connecting pipe, and a joint is used in which an airtight material is built into the inner surface of the socket of the joint connecting part, and the connecting pipe is connected to the connecting part. In a connection method in which the joint is inserted, the diameter of the joint is reduced, and the joint is crimped onto the inserted connection pipe, at least one arc-shaped cross section is formed on the circumferential surface within the joint diameter reduction range toward the pipe axis. A pipe connection method characterized by the provision of protrusions. 2. The pipe connection method according to claim 1, wherein the protrusion having an arcuate cross section is a spherical protrusion. 6. Permissible scope of claim 1. The pipe connecting method according to claim 1, wherein the protrusion on the arcuate cross section is a protrusion having a length within the diameter reduction range in the direction in which the fluid in the pipe flows.