JP2003266133A - Bulging method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To require no prebending nor annealing incidental to it and to reduce the number of processes compared with a conventional machining method. <P>SOLUTION: A pipe P is set on the left and right split dies 1, 2 which are formed by dividing a pair of upper and lower dies for bulging at the bulged part in the longitudinal direction of the pipe. Both ends of the pipe are each fitted with core bars 3, 4 and pressurized with the core bars 3, 4 by a prescribed pressurizing force in the pipe axial direction. While the inner pressure of the pipe is raised to a predetermined pressure level, the right split die 2 is lowered until the left and right split dies 1, 2 coincide with the shape of the original dies for bulging. While both ends of the pipe are pressurized with the core bars 3, 4 by the prescribed pressurizing force in the pipe axial direction, the inner pressure of the pipe P is raised until the pipe P comes into close contact with the dies for bulging. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the technical field of a bulge processing method and a bulge processing apparatus for forming a curved bulge on a pipe.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a curved bulge portion on a pipe, for example, a technique described in Japanese Patent No. 3205105 is known. This prior art is to form a deformed curved pipe having a three-dimensionally bent side shape by bending (pre-bending) the pipe into a predetermined shape in advance before bulging the pipe. is there.

[0003]

However, the above-mentioned prior art has the following problems. (A) When pre-bend processing is performed, the pipe undergoes work hardening and its hardness increases, which adversely affects the bulge formability. (B) Depending on the bending shape of the pipe, it is necessary to soften the pipe by annealing after the prebending process in order to prevent the occurrence of cracks during the bulging process. In that case, since the number of steps is large and annealing requires a long time, the manufacturing cost increases.

The present invention has been made in view of the above problems, and its object is to reduce the number of steps as compared with a conventional processing method without requiring prebend processing and the accompanying annealing. An object of the present invention is to provide a bulge processing method and a bulge processing device that can be achieved.

[0005]

In order to achieve the above-mentioned object, in the bulging method according to claim 1, in the bulging method of forming a curved bulged portion in the pipe, the pipe is paired with a pair of upper and lower parts. Set the bulge mold into a plurality of split molds formed by dividing the bulge mold in the bulge part in the pipe length direction, airtightly abut the metal cores on both ends of the pipe, and use the metal cores on both ends of the pipe. While pushing in the pipe axial direction, while increasing the pipe internal pressure to a preset predetermined pressure, the split mold is relatively moved until the split mold matches the shape of the original bulge mold, and both ends of the pipe are It is characterized in that the internal pressure of the pipe is increased until the pipe comes into close contact with the bulge type while pressing the core metal in the axial direction of the pipe.

According to a second aspect of the present invention, there is provided a bulging device for forming a curved bulging portion on a pipe, in which a pair of upper and lower bulge dies are divided in the pipe length direction by the bulging portion of the bulge type. A plurality of split molds formed by the above, and split mold moving means for relatively moving the plurality of split molds,
A cored bar which can be abutted against both ends of the pipe in an airtight manner, and which has one side formed with a hydraulic pressure supply hole for supplying a hydraulic pressure to the inside of the pipe, and presses the cored bar in the axial direction of the pipe with a predetermined pressing force, A core metal moving means for relatively moving the core metal along the relative movement of the split mold, and a hydraulic pressure supply means for supplying a hydraulic pressure to the inside of the pipe from a hydraulic pressure supply hole of the core metal. And

[0007]

In the bulging method according to the first aspect of the present invention, first, the pipes are set in a plurality of split molds, and the cores are abutted against both ends of the pipes in an airtight manner. At this time, the bulge-shaped bulging portion of the split mold is displaced vertically or horizontally, and the pipe is fixed to the split dies except for the bulging portion including both ends of the pipe. .

Subsequently, while the both ends of the pipe are pressed by the cored bar in the axial direction of the pipe with a predetermined pressing force, and the internal pressure of the pipe is increased to a predetermined pressure set in advance, the split mold is the original bulge mold. Move the split dies relatively until they match the shape of. At this time, the pipe is bent along the processed shape, but since a predetermined internal pressure is applied to the pipe, crushing and ovalization of the pipe are suppressed. Further, since both ends of the pipe are axially pressed by the cored bar to prevent the thickness of the bent outer portion from being reduced as much as possible, the occurrence of cracks and wrinkles is suppressed.

When the split mold matches the shape of the original bulge mold, the inner pressure of the pipe is increased until the pipe is in close contact with the bulge mold of the split mold while pressing both ends of the pipe in the axial direction of the pipe with the core metal. By doing so, a pipe having a curved bulged portion is formed.

Therefore, the bulging method of the present invention does not require pre-bending before bulging and annealing accompanying the pre-bending, and therefore, compared with the conventional processing method,
The number of steps can be reduced and the manufacturing time can be shortened.

In the bulging apparatus according to the second aspect of the present invention, while the core metal moving means presses the core metal in the pipe axial direction and the hydraulic pressure supplying means increases the internal pressure of the pipe, the split mold moving means divides the pipe. Bulge processing using the bulge processing method according to claim 1 is performed by relatively moving the mold. Therefore, the same effect as the invention described in claim 1 can be obtained.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment for realizing a bulge processing apparatus of the present invention will be described below based on a first embodiment corresponding to the inventions according to claims 1 and 2.

(First Embodiment) FIG. 1 is a schematic configuration diagram showing the configuration of a bulge processing apparatus. In the figure, P is a pipe, 1 is a left split mold, 2 is a right split mold, 3 is a left core metal, 4
Is the right core.

The left split mold 1 is a pair of upper and lower upper molds 1a.
And a lower mold 1b. Similarly, the right split mold 2 also
It has a pair of upper and lower molds 2a and 2b. The shape of the bulge mold, which is a combination of these left and right split molds 1, 2, is the processed shape of the pipe P, that is, the diffuser D shown in FIG.
The product shape is set to match the left and right. The right split mold 2 can be moved up and down in the vertical direction by a lifting device using a hydraulic cylinder as a split mold moving means (not shown).

The left and right metal cores 3 and 4 are formed to have the same diameter as the pipe P, and the tips 3a and 4a thereof are reduced in diameter so that they can be fitted into the ends of the pipe P. The portion abutting on the pipe P is formed to be airtight in a state of being fitted into the end portion.

A hydraulic pressure supply hole 3b is axially provided inside the left core metal 3, and a hydraulic pressure is supplied from the tip portion 3a into the pipe P by an oil pump 5 which is a hydraulic pressure supply means. It is possible to supply.

The other ends of the left and right metal cores 3, 4 are connected to the left and right metal cores 3, 4 respectively.
Are fixed to oil cylinders 6a and 6b as core metal moving means for moving the cylinder in the pipe axial direction. The right core metal 4 and the oil cylinder 6b are supported by the elevating device and can be vertically moved together with the right split mold 2.

Control of the split die moving means for moving the left split die 2 up and down, the oil cylinders 6a, 6b for pressing the left and right cores 3, 4 and the oil pump 5 for supplying hydraulic pressure to the inside of the pipe P are as follows. It is controlled by a control unit (not shown).

Next, a bulging method using the bulging apparatus of this embodiment will be described. First, as shown in FIG. 2, the pipe P is set in the left split mold 1 and the right split mold 2. At this time, the bulge-shaped bulging portions 1c and 2c of the left split mold 1 and the right split mold 2 are vertically displaced, and the pipe P is fixed to the left and right split molds 1 and 2 at both pipe ends. ing.

Next, at both ends of the pipe P set in the left and right split molds 1 and 2, tip portions 3a and 4a of the left and right cored bars 3 and 4 are provided.
Insert each. At this time, the contact portion 3 with the pipe P
c and 4c are airtight.

Subsequently, as shown in FIG. 3, the left and right metal cores 3,
While pressing both ends of the pipe P with a predetermined pressing force in the axial direction of the pipe P by 4, the hydraulic pressure is supplied from the oil pump 5 to the inside of the pipe P through the hydraulic pressure supply holes 3b of the left core metal 3 to thereby cause the pipe P to move. While increasing the internal pressure of the to a preset predetermined pressure,
The right split mold 2 is lowered by the lifting device until the bulging portions 1c, 2c of the left and right split molds 1, 2 match the shape of the bulge mold.

At this time, the pipe P is bent along the processed shape, but since a predetermined internal pressure is applied to the pipe P by the oil pump 5, crushing and ellipticization of the pipe P is suppressed. Has been done. Furthermore, by pressing both ends of the pipe in the axial direction of the pipe with the left and right cored bars 3 and 4,
Since the thickness of the outer side portion of the bend is not reduced as much as possible, generation of cracks and wrinkles is suppressed.

Bulging parts 1c, 2 of the left and right split molds 1, 2
When c coincides with the bulge type, as shown in FIG. 4, the outer periphery of the pipe P is expanded while the left and right cored bars 3 and 4 press both ends of the pipe P in the axial direction of the pipe. Debu 1
By supplying hydraulic pressure to the inside of the pipe P from the oil pump 6 through the hydraulic pressure supply hole 3b of the left core metal 3 until it comes into close contact with c and 2c, a bulge molded product as shown in FIG. 5 is formed. It

Next, the effect will be described. The bulge processing apparatus and the bulge processing method according to the present embodiment have the following effects as compared with the conventional processing method. (1) Since the pre-bending process before the bulge process is unnecessary, the number of processes can be reduced. (2) Since the annealing associated with the pre-bending process is unnecessary, the manufacturing time can be greatly reduced. (3) No equipment for pre-bending is required.

(Other Embodiments) The embodiments of the present invention have been described above. However, the specific configuration of the present invention is not limited to this embodiment, and is within the scope of the present invention. Even if there is a design change or the like, it is included in the present invention.

For example, in this embodiment, an example using two left and right split molds has been shown, but depending on the processed shape of the pipe, three or more split molds may be used to form a plurality of bulging portions. Can also be formed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a configuration of a bulge processing apparatus.

FIG. 2 is a cross-sectional view showing a bulge processing method.

FIG. 3 is a cross-sectional view showing a bulge processing method.

FIG. 4 is a cross-sectional view showing a bulge processing method.

FIG. 5 is a cross-sectional view showing a processed shape of a pipe.

[Explanation of symbols]

D diffuser P pipe 1 Left split mold 1a Upper mold 1b Lower mold 1c bulge 2 Right split mold 2a Upper mold 2b Lower mold 2c bulge 3 left core 3a tip 3b Hydraulic pressure supply hole 3c contact part 4 Right core metal 4a tip 4c contact part 5 Oil pump (hydraulic pressure supply means) 6a, 6b Oil cylinder (core bar moving means)

Claims (2)

[Claims] 1. A bulging method for forming a curved bulging portion on a pipe, wherein a plurality of bulge metal molds formed by dividing a pair of upper and lower bulge dies into bulging portions of the bulge die in the length direction of the pipe. Set in a split mold, the airtightly abutting the core metal on both ends of the pipe, while pressing both ends of the pipe in the axial direction of the pipe with the core metal, while increasing the internal pressure of the pipe to a predetermined pressure set in advance,
The split mold is relatively moved until the split mold matches the shape of the original bulge mold, and both ends of the pipe are pressed in the axial direction of the pipe by the core metal, and the internal pressure of the pipe is kept until the pipe comes into close contact with the bulge mold. A bulge processing method characterized by raising the. 2. A bulging device for forming a curved bulging portion on a pipe, wherein a plurality of split dies formed by dividing a pair of upper and lower bulge dies into bulging portions of the bulge die in the pipe length direction. A split metal mold moving means for relatively moving the plurality of split metal molds, and a core metal capable of abutting airtightly on both ends of the pipe and having one formed with a hydraulic pressure supply hole for supplying a hydraulic pressure to the inside of the pipe. A core bar moving means for pressing the core bars in the axial direction of the pipe with a predetermined pressing force and moving the core bars relatively along the relative movement of the split mold; A bulge processing apparatus comprising: a hydraulic pressure supply unit that supplies hydraulic pressure to the inside.