JPS61111726A - Working method for pipe end of steel pipe - Google Patents

Abstract

PURPOSE:To form a piping joint with a press work without a skill fullness by folding back the face of the end part with inserting the second metal die into the expanded steel pipe end part after expanding the pipe so that the face of the end part can be inclined for the axial core with inserting the first metal die into the end part of a steel pipe. CONSTITUTION:A metal die 11 has a tapered face 11a and the diameter A of an inserting part is approximately same as the inner diameter of a steel pipe 10. The angle made by the tapered face 11a and the axial core of the steel pipe 10 is 45 deg.. The pipe expansion is then performed with inserting the metal die 11 into the end part 10a of the steel pipe 10 at the first step. a metal die 12 has the folded back face 12b which is at right angle to the axial core in continuation to a curved face 12a and also the diameter A of the inserting part is almost equal to the inner diameter of the steel pipe 10. And it is inserted into the end part 10a of the steel pipe 10 which is expanded by the metal die 12 at the second step. Then the face of the end part 10a is curved smoothly by the curved face 12a and further folded back at right angles to the axial core by the folded back face 12b and a pipe joint face is made. With inserting a loose flange 13 a joint is formed.

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a method for processing the end of a copper pipe, and is intended to facilitate the formation of a joint for a copper pipe. <Conventional technology> Medium-sized diameter copper pipes and copper alloy pipes (
(hereinafter referred to as copper pipes),
Examples include those shown in FIGS. 5 to 7. That is, in the one shown in FIG. 5, a brass flange 2 is welded to a copper tube l. Welded part 3 is made by BRAZING (with solder) or TI
Welded by G welding/MIG welding. The one shown in FIG. 6 uses a combination type flange consisting of an inner flange 4 made of brass and an after flange 5 made of steel, which are welded to a copper pipe 1. Welded part 611 BRAZIN
Welded by G or TIG welding/MIG welding
ing. In the one shown in FIG. 7, a loose flange 8 made of steel is provided on a flange forming piece 7 which is welded to a copper pipe 1 and has a hole formed therein. The welded portion 9f'iB is welded by RAZ I NG, TIG welding, or MIG welding. <Problems to be solved by the invention> As mentioned above, advanced welding technology (BRAZING +TIG/MIG welding-) is required to form pipe joints for copper systems.
This work requires a high level of skill and is generally done by hand. Furthermore, expensive welding materials (silver solder, phosphor solder, brass solder) were not used in the towara work, resulting in a negligible increase in final cost. Furthermore, if the welding is defective, there is a risk that leakage may occur from there. SUMMARY OF THE INVENTION In view of the above-mentioned prior art, it is an object of the present invention to provide a method for processing the end of a copper pipe, by which a joint can be formed by press working without using welding. Means for Solving the Problems> The present invention achieves the above object by inserting a mold having a tapered surface into the end of a copper tube so that the end surface is inclined with respect to the axis. Then, by inserting a mold having a curved surface for curving the end and a folded surface continuing from the curved surface and perpendicular to the axis into the end of the expanded NFCM pipe, this end is It is characterized by being folded back so that the surface of the part is perpendicular to the axis. Examples> The method of the present invention will be specifically explained below. This method consists of two steps. In the first step, a mold 1 as shown in FIG.
1 is used. This mold 11 has a tapered surface 11a, and the diameter A of the insertion portion is approximately equal to the inner diameter of the copper tube IO. Angle θ between the tapered surface 11a and the axis of the copper tube IO
deep red,

[4c: In the first step, the mold】l
is inserted into the end portion 10a of the copper tube IO to expand the tube. As a result, the surface of the end portion 10a is inclined by 4c with respect to the axis. In this case, if the copper tube lO is 50A or less, if the angle θ made on the mold 11 is set to 4d'' to 5C, the copper tube lO
No thinning phenomenon occurs at the bent portion of the O, rather the thickness of the bent portion increases due to the action of compressive force. In the second step, a mold 1 as shown in FIG.
2 is used. This mold 12 has a curved surface 12a and a folded surface 12b that is continuous with the curved surface 12a and is perpendicular to the axis ζ (2), and the diameter A of the insertion portion is the copper tube lO.
It is almost equal to the inner diameter of. In the second step, the mold 12 is inserted into the end 10a of the expanded copper tube IO. Then, the surface of the end portion 10a is smoothly curved at the curved surface 12a, and further folded back at the folding surface 12b to be perpendicular to the axis. In this case, if the copper tube lO is 50A or less, the radius of the curved surface 12a of the mold 12 is 3 to 5.
Optimum machining can be achieved with +a. If the value of R is smaller than n, thinning phenomenon will occur at the bent portion, so this must be avoided. On the other hand, if the radius value is too large, the engagement portion between the loose flange attached to the copper tube 10 and the end portion 10a will be reduced, as will be described later. If a loose flange is fastened fc, watertightness will be reduced. Note that the first thing. Although not shown in the second step,
A copper tube lO is clamped. When the copper pipe is a pipe of 50A or less, it is just right if the distance t from the tip of the copper pipe to the clamp part is 20 to 22 mm. The end portion 10a of the copper tube 10 after the two steps has been completed becomes a pipe joint surface as shown in FIG. And this copper pipe lO
A joint is formed by inserting the loose flange 13 into. In addition, when processing both ends of the copper pipe IO, after the processing of one end is completed, two loose flanges are inserted into the copper pipe before processing the other end. Generally, when the folding process is performed, the thickness of the plate becomes thinner at that part, but if one method is used, the thickness of the plate at the folded part actually increases. Therefore, strength and reliability are improved. Next, a special equipment for processing according to the present method will be explained with reference to FIG. 3, which is a plan view, and FIG. 4, which is a front view. As shown in both figures, the clamping hydraulic cylinder 20 and the machining hydraulic cylinder 21 are connected to the oil tank 2 by the hydraulic motor 22.
Pressure oil is supplied and discharged from hole 3 to operate. The clamping hydraulic cylinder 20 is equipped with a mold 25 that moves along the groove 24. Also, a mold 26 is fixedly installed opposite the mold 25.
ing. The copper tube IO is sandwiched and clamped between the molds 25 and 26. The processing hydraulic cylinder 21 is equipped with a mold 28 via a mold socket 27 . This mold 28 can be replaced with one touch by operating a lever 29 of the mold socket 27. And this mold 28
When the processing cylinder 21 expands, the copper pipe lO
inserted into the end of the The pushing force of the clamping hydraulic cylinder 20 and the processing cylinder 21 is received by the support block 30.31. Note 32
33 is an electrical system control panel for manual or automatic operation. The processing procedure using this device will be described. First, the copper pipe IO is set, the clamping hydraulic cylinder 20 is extended, and the copper pipe IO is clamped by the molds 25 and 26. The mold 28 is of the type shown in FIG. 1(a). Extend the hydraulic cylinder for processing by 21% and move the mold 28 to the copper pipe lO
Insert it into the end of the tube and perform the first step of processing. Retract the machining hydraulic cylinder 21. The mold 28 is replaced with one of the type shown in Fig. 1). The processing hydraulic cylinder 21 is extended again and the mold 28
is inserted into the end of the copper tube IO and processed in the second step. When the two processes are completed, take out the copper pipe IO and attach a loose flange to it. With this device, the mold 28 can be replaced with one touch, and one operation can be done quickly. <Effects of the Invention> As specifically explained above in conjunction with the embodiments, according to the present invention, a copper pipe joint is formed by press working, which eliminates the need for work that requires skill as in the past. Joints of constant quality can be easily produced with simple operations.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are explanatory diagrams for explaining the method of the present invention, Figure 2 is a sectional view showing a copper tube processed by the method of the present invention, and Figure 3 is a diagram showing the method of the present invention being carried out. A plan view showing the device, and FIG. 4 is a front view thereof. FIGS. 5 to 7 are cross-sectional views showing the prior art. Inside the drawing. lO is a copper tube. 10a is the end. 11.12 is the mold. 11a is a tapered surface. 12a is a curved surface. x2b is a folded surface.

Claims (1)

[Claims] By inserting a mold with a tapered surface into the end of a copper tube, the pipe is expanded so that the surface of this end is inclined with respect to the axis, and then a curved surface that curves the end and a continuation of this curved surface are formed. In addition, by inserting a mold having a folding surface perpendicular to the axis into the end of the expanded copper tube, the pipe is folded back so that the surface of this end becomes perpendicular to the axis. How to process the ends of copper pipes.