JPH01254317A - Forming method for branch pipe - Google Patents

Abstract

PURPOSE:To form a branch pipe on a thin metal member with good accuracy by press-fitting the drive member having a tapered part and circular columnar part from its tapered part side from the projecting side of the projecting opening part formed on a pipe blank stock. CONSTITUTION:A drive member 12 is formed by the circular columnar part 13 having the outer diameter corresponding to the inner diameter of a forming branch pipe 4 and by a tapered part 13A in succession. When the tapered part 16 of the drive member 12 is press-fitted to the opening part 5 of the branch pipe 4 first, the peripheral part 11 of a bulged projecting part 2 is elongated by attaining upward as well as expanded in the outside direction. When it comes in the pressure fitting stage of the circular columnar part 13 then, the buckling in the outside direction is stopped and it becomes in a circular columnar shape by being elongated along the outer peripheral face 23 by the spring back of an elastically flexing part 20. Consequently the branch pipe 4 onto a pipe blank stock 1 can be formed.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for forming a branch pipe into a thin metal member.

(Prior art) In order to form a branch pipe on a pipe material, as shown in FIG.
There is a method of forming the branch pipe 4 by cutting the lower part of the top surface 3 of the bulging protrusion 2, or a method of forming the bulging protrusion 2 by bulge processing as shown in Figs. A protruding opening 5 is formed on the top surface 3, and a molding material 6 is formed on the outside of the protruding protrusion 2.
After making contact with each other, the die 7 is inserted into the tube material 1 through the opening 8 of the tube material 1, and the bar 9 is inserted into the tube material 1 through the protruding opening 5 to join the die 7 and the bar 9. By doing so, a burring tool 10 is obtained, and this burring tool 1
0 toward the protruding opening 5 side as shown in the twelfth figure, the peripheral edge 11 of the protruding protrusion 2 is removed from the outer circumferential surface 7a of the die 7.
A commonly used method is to extend the branch pipe 4 in the axial direction to form the branch pipe 4 having an inner diameter corresponding to the outer diameter of the die 7.

(Problems to be Solved by the Invention) However, in the above conventional method as shown in FIG. There is a problem in that it is difficult to obtain long branch pipes because there are restrictions on the ductility of the material, wall thickness, etc. in forming long protrusions. Furthermore, with the method shown in FIGS. 10 to 12, the length of the branch pipe can be formed longer than with the method shown in FIG. Branch pipes are formed by inserting the bar into the pipe material, joining the die and bar, and then pulling out the die, which requires time and labor to form the branch pipe, which poses problems in terms of productivity. Ta.

In view of this, the present invention aims to form highly accurate branch pipes with high productivity through a simple process without using a conventional burring tool using a die and bar when forming branch pipes that require a long length. The purpose of the present invention is to provide a method for forming a branch pipe.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a part of the thin metal member is protruded and its tip is opened to form a protruding opening, and the inner diameter of the branch pipe to be formed is A driving member having a cylindrical portion having an outer diameter corresponding to the diameter of The press-fitting movement causes the peripheral edge of the protruding opening to extend in the axial direction on the outer peripheral surface of the driving member, thereby forming the protruding opening into a cylindrical shape.

(Function) According to the present invention, as a method for forming a branch pipe into a thin-walled metal member, a driving member having a tapered portion and a cylindrical portion is inserted into the thin-walled metal member from the protruding side of a protruding opening formed in the thin-walled metal member. By press-fitting using a press-fitting means with the side facing toward the tip, a branch pipe can be formed by extending the peripheral edge of the protruding opening in the axial direction on the outer circumferential surface of the driving member.

(Embodiment) Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings, using the same reference numerals for parts common to FIGS. 9 to 12.

Figures 1 to 7 show an embodiment in which a branch pipe is formed on the side surface of a pipe material, in which a bulge protrusion 2 is formed on a part of the outer periphery of the pipe material 1 by bulge processing, and the bulge A protrusion opening 5 having a smaller diameter than the inner diameter of the bulging protrusion 2 is formed in the top surface 3 of the protrusion 2 .

The driving member 12 is made of steel or the like, and as shown in FIG. 2, it has a cylindrical portion 13 having an outer diameter corresponding to the inner diameter of the branch pipe 4 to be formed, and a tapered portion 1 that tapers following the cylindrical portion 13.
It consists of 3A. In this embodiment, the tapered portion 13A gradually decreases from 20″ to 20″ from the cylindrical portion 13.
a tapered section 14 having an angle of 40', followed by a tapered section 14 having an angle of 40';
The tapered portion 15 has an angle of 0° to 20′ and further has an angle of 0° to 20′.
A tapered part 16 having an angle of 6 to 10'' is continuously formed, and the diameter (d) of the tip of the tapered part 16 is equal to the bulging protrusion 2.
The diameter (dl) of the protruding opening 5 is equal to or slightly smaller than the diameter (dl) of the protruding opening 5 formed in the opening.

Further, the total length of the driving member 12 is shorter than the diameter of the tube material 1 plus the height of the protruding portion 2, and the cylindrical portion 13 and each of the tapered portions 14, 15 and 16 are formed to have approximately equal lengths. has been done.

Next, the molding method of this embodiment will be explained with reference to FIGS. 3 to 7.

First, as shown in FIGS. 3 and 4, when the tapered part 16 of the driving member 12 is press-fitted into the protruding opening 5 from the protruding side of the protruding protrusion 2 of the tube material 1 using a press machine, the tapered part The inner circumferential surface 18 of the protruding opening 5 is
is pushed outward, so that the peripheral edge 11 expands outward. Further, when the driving member 12 is press-fitted,
As shown in FIG. 5, the peripheral edge 11 of the protruding protrusion 2 is expanded outwardly by the outer circumferential surface 19 of the tapered portion 15 to produce a bent portion 20, and the inner circumferential surface 18 of the protruding opening 5 is Tapered part 1
It is slightly upward along the outer circumferential surface 19 of 5. followed by the 6th
As shown in the figure, when the driving member 12 is further press-fitted,
Since the angle of the tapered portion 14 is large, the inner circumferential surface 18 of the protruding opening 5 expands outward along the outer circumferential surface 21 of the tapered portion 14 and becomes more and more upward.
Also expands. Next, when the cylindrical part 13 of the driving member 12 is press-fitted, the protruding opening 5 is opened as shown in FIG.
The inner circumferential surface 18 of the cylindrical portion 1 has no taper.
3 is press-fitted, the buckling in the outward direction is stopped, and the inner circumferential surface 22 of the bulging protrusion 2 is expanded along the outer circumferential surface 23 of the cylindrical portion 13 due to the springback of the bending portion 20. It becomes cylindrical. Thereafter, the driving member 12 is pulled out above the projecting opening 5, thereby completing the forming of the branch pipe 4 onto the tube material 1.

Note that when the driving member 12 is press-fitted into the protrusion opening 5, a mold material may be brought into contact with the outer surface of the bulging protrusion 2.

In this embodiment, the protruding opening 5 is formed in the pipe material 1, but the protruding opening 5 formed by drilling a pilot hole in the plate material 24 as shown in FIG. 4, and is not limited to the shape of the thin metal member.

〔Effect of the invention〕

As explained above, the present invention includes press-fitting a driving member having a tapered portion and a cylindrical portion into a protruding opening formed in a thin metal member from the protruding side using a press-fitting means. Since this is a method of forming a branch pipe in a thin metal member by extending the peripheral edge of the protruding opening in the axial direction on the outer peripheral surface of the driving member, it does not require a complicated tool that uses a die and a bar as in the past. without using
It is possible to form high-precision branch pipes with high productivity in one action using a simple tool, and even when combined with bulge processing, long branch pipes can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view of a tube material in which a protruding opening is formed, FIG. 2 is a front view showing an example of a driving member used in the method for forming a branch pipe according to the present invention, and FIG. 4 is a sectional view taken along the line A-A in FIG. 3, and FIG. 5 is a front view of the state in which the tapered portion is press-fitted between the protrusions in FIG. 4. sectional view, FIG. 6 is a front sectional view of the state in which the tapered part is press-fitted to the bottom part between the protrusions in FIG. 4;
7 is a front cross-sectional view of the cylindrical portion press-fitted into the protruding opening shown in FIG. 4, FIG. 8 is a perspective view of the protruding opening formed in the plate material, and FIGS. 9 to 12 are the conventional Fig. 9 is a front cross-sectional view when the top surface of the bulging protrusion of the tube material is cut and opened, and Fig. 10 is a front sectional view when the top surface of the bulging protrusion is formed with a protruding opening. FIGS. 11 and 12 are front sectional views showing the case where a branch pipe is formed using a burring tool consisting of a die and a bar. 1... Pipe material, 2... Swelling protrusion, 3... Top surface, 4
... Branch pipe, 5 ... Projection opening, 6 ... Shape material, 7.
...Die, 9... Bar, 10... Burring tool, 12... Driving member, 20... Flexible part, 24...
・Plate material. Applicant's agent Sato - Otara 3 Figure 4 Figure Tame 5 Figure 6z Figure 7 Figure 8 Figure Figure 9 Figure n Tame 11 Figure 10 Figure 12

Claims (1)

[Claims] A protruding opening is formed by protruding a part of the thin metal member and opening its tip, and has a cylindrical part having an outer diameter corresponding to the inner diameter of the branch pipe to be formed, and a tapered part that gradually decreases from the cylindrical part. A driving member is press-fitted into the projecting opening using a press-fitting means, with the tapered part side facing toward the distal end, and by the press-fitting movement of the driving member, the peripheral edge of the projecting opening is moved in the axial direction with the outer circumferential surface of the driving member. A method for forming a branch pipe, characterized in that the projecting opening is formed into a cylindrical shape.