JPH06226341A - Manufacture of branch tube for piping - Google Patents

Abstract

PURPOSE:To inexpensively manufacture a branch tube for piping stable in dimensional accuracy by working bar-shaped or tubular metallic base stock into a tube shape of different diameters, and then drawing the outside surface of the tube in the axial direction. CONSTITUTION:A branch tube base stock 10 having a tube shape of different diameters is manufactured by press forging, etc., from a bar-shaped or tubular material. This branch tube base stock 10 is inserted into a guide part 7 of a drawing die 4. A pressing punch 1 is advanced into the branch tube base stock 10 and abuts on the stock 10 and when it is advanced further, the branch tube base stock 10 is pressed by the pressing punch 1 into a branch port outside surface forming part 6 and drawn to form a branch port 32 while moving in the axial direction. At the same time, at the tip part a inflow port 31 is finished into a prescribed dimension to form a desired branch tube 30. Thereafter, the extruded branch tube 30 is ejected from the drawing die 4 with a projection pin 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a branch pipe for piping used in a heat exchanger or the like.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 9, a large number of branch pipes 40 for branching from a main pipe to a branch pipe are used in a pipe portion of a heat exchanger incorporated in an air conditioner or the like. There are various types of branch pipes having a branch port 41 with two, three or more branch ports, and conventionally, they are manufactured by press working, cutting work or special press work.

[0003]

However, in the case of the above-mentioned conventional press working, due to its characteristics, it is very difficult to set an appropriate material volume, and the deformation regulating die becomes complicated, and the hole diameter dimension of the product is also increased. There is a drawback that the variation becomes large and unstable. Further, this method has a problem that productivity is low and therefore cost is high. On the other hand, in cutting, there is a problem that the material cost is extremely high because it is cut from a large raw material, and it takes a lot of time to completely remove burrs and chips, which are important for quality, and productivity is poor and the cost is high. In the special press working, a method of using a heavy metal such as lead is used to push the material in different directions while suppressing the hole diameter deformation. The use of this heavy metal poses a problem in terms of pollution control. The present invention is intended to solve these problems and to inexpensively manufacture a branch pipe for piping by using an ordinary forging machine without using heavy metals.

[0004]

To achieve this object, a branch pipe for branching from a main pipe to a plurality of branch pipes, which is obtained by processing a rod-shaped or tubular metal material into a pipe having a different diameter. A method for manufacturing a branch pipe for piping, in which an outer surface of the pipe is axially drawn by a drawing die to form a branch pipe branch port.

[0005]

The branch pipe material 10 processed into a different diameter pipe shape by forging or cutting is inserted into the guide portion 7 of the drawing die 4, and then the pushing punch 1 is advanced into the branch pipe material 10 and brought into contact therewith, When this is further advanced, branch pipe material 1
0 is pushed by the pushing punch 1 into the branching port outer surface forming portion 6 of the drawing die 4, the branching pipe material 10 is drawn while moving in the axial direction to form the branching port 32, and the inflow port 31 is formed at the tip end at a predetermined position. The desired branch pipe 30 can be formed into the desired size. Thereafter, the branch pipe 30 is discharged from the drawing die 4 by the projecting pin 8.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an embodiment, and a method of manufacturing a branch pipe 30 having an inflow port 31 and a branch port 32 communicating with the inflow port 31 as shown in FIGS. 4 and 5 will be described. In FIG. 1, reference numeral 1 is a push-in punch, and a columnar portion 2 is provided at the tip, and a branching port forming portion 3 for molding a branching port 32 behind the columnar portion 2 is formed.
have. The outer diameter of the columnar portion 2 is formed to the size of the inflow port 31 of the branch pipe 30.
The cross section of is formed in substantially the same shape as the cross section of the branch port 32 of the branch pipe 30, and is integrally formed by being connected to the cylindrical portion 2 by a smoothly curved surface. 4 in the drawing is a drawing die,
A through hole 5 is provided in the front, a branch port outer surface molding part 6 for molding the outer peripheral surface of the branch port 32 of the branch pipe 30 is provided in the middle part, and a guide part 7 into which the branch pipe material 10 is inserted is further formed in the rear part. Has been done. The inner diameter of the through hole 5 is formed to be substantially the same as the diameter of the outer surface of the inflow port 31 of the branch pipe 30, and penetrates to the front end of the drawing die 4. The cross section of the branch port outer surface molding portion 6 is the branch port 3 of the branch pipe 30 shown in FIG.
The outer peripheral surface of No. 2 is formed in a cross-sectional shape and is formed to have substantially the same dimensions as A and B, and is connected to the through hole 5 by a smooth curved surface. The dimension of the guide portion 7 is A, which is slightly larger than the maximum dimension A of the outer surface molding portion 6 of the branch opening.
It is a circular hole of one dimension, and is connected to the front branch outer surface molding portion 6 by a smooth curved surface. Reference numeral 8 in the figure denotes a protruding pin, into which a rod member having a diameter slightly smaller than the through hole 5 is inserted so as to be able to move forward and backward. The drawing die 4 and the pushing punch 1 are attached to an ordinary press machine (not shown), and the pushing punch 1 is moved forward and backward to a predetermined position in the fixed drawing die 4.

In this manufacturing method, first, a branch pipe material 10 having a different diameter pipe shape is prepared by using a rod-shaped or tubular copper-based material as shown in FIGS. Large diameter part A0 of this branch pipe material 10
Is manufactured into a cylindrical shape that is slightly larger than the A dimension and slightly smaller than the A1 dimension by forging (or cutting) or the like. Next, the branch pipe material 10 is inserted into the guide portion 7 of the drawing die 4, and then the pushing punch 1 is advanced into the branch pipe material 10 and brought into contact therewith. 1 is pushed into the branch port outer surface molding portion 6 and is squeezed while moving in the axial direction to mold the branch port 32, and at the tip end, the inflow port 31 is finished to a predetermined size and the desired branch pipe 30 is molded. To be done. After that, the branch pipe 3 is projected by the projecting pin 8.
0 is discharged from the drawing die 4.

In this embodiment, a branch pipe material 1 having a different diameter pipe shape
Although the molding is completed by drawing from 0 to 1 times, if it is difficult to mold it once by the conditions such as the material of the branch pipe and the number of branch ports, the branch pipe material 10 is pushed into the second position as shown in FIG. The punch 11 and the second drawing die 12 form a preform 20 having a shape as shown in FIGS. 7 and 8. Second at this time
The guide portion 13 of the drawing die is a circular hole having the A1 size,
The preforming portion 14 may have a cross section having an A2 size smaller than the A1 size and slightly larger than the A size and a B1 size slightly larger than the B size. Thereafter, the branch pipe 30 can be formed by performing the finish forming process as described above with the pushing punch 1 and the drawing die 4 described in FIG.

[0009]

As is apparent from the above description, the present invention is a branch pipe for branching and connecting a main pipe to a plurality of branch pipes, in which a rod-shaped or tubular metal material is processed into a pipe having a different diameter. After that, the outer surface of the pipe is drawn axially by a drawing die to form a branch port. According to the present invention, since it is possible to mass-produce at high speed with a normal cold heading machine, it is possible to manufacture a branch pipe which is extremely inexpensive as compared with conventional cutting work, press work, etc. The dimensional accuracy of each part is stable and the reliability against gas leakage is improved. In addition, since heavy metals are not used, it is possible to obtain a great effect that the pollution control process becomes unnecessary.

[Brief description of drawings]

FIG. 1 is a sectional explanatory view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a branch pipe material.

FIG. 3 is a side view of FIG.

FIG. 4 is a completed sectional view of a branch pipe.

FIG. 5 is a side view of FIG.

FIG. 6 is an explanatory sectional view showing an example of preforming.

FIG. 7 is a cross-sectional view of a preformed product.

FIG. 8 is a side view of FIG. 7.

FIG. 9 is a perspective view of a conventional branch pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Push-in punch 2 Cylindrical part 3 Branch opening forming part 4 Drawing die 5 Through hole 6 Branch opening outer surface forming part 7 Guide part 8 Projecting pin 10 Branch pipe material 20 Preform 30 Branch pipe 31 Inlet 32 Branch port

Claims (1)

[Claims] 1. A pipe branch pipe for branching and connecting a main pipe to a plurality of branch pipes, wherein a rod-shaped or tubular metal material is processed into a pipe having a different diameter, and then the outer surface of the pipe is drawn by a drawing die. A method for manufacturing a branch pipe for piping, which comprises axially drawing to form a branch port.