JP2510609B2 - Manufacturing method of pipe with projection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a projection for integrally molding a projection such as when a branch pipe is formed around a pipe material like a manifold. The present invention relates to a method for manufacturing a pipe with a cover.

(Prior Art) In some cases, a branch pipe is provided around a pipe material to connect another pipe material or equipment.

Conventionally, such a branch pipe is formed by forming a hole around the pipe material and welding the end portion of another pipe material to this hole portion, but according to this, when there are many branch pipes, Not only is the welding process extremely time-consuming, but the heat during welding causes deterioration of the strength of the pipe material.

From the above, a bulge processing method has recently been used as a means for forming a branch pipe.

Molding a branch pipe by this bulge processing method, the pipe material is placed inside a bulge mold having a branch pipe molding die,
A high-pressure fluid is press-fitted into this pipe material to bulge part of the pipe material into the branch pipe molding die, and after this bulging molding, the tip is cut off or pierced at the tip to form a branch pipe. is there.

(Problems to be Solved by the Invention) However, in forming a branch pipe by the above-mentioned bulge processing method, when a part of the pipe material is expanded, the material of the other part is brought close to the expanded deformation part and expanded. Since the bulging portion is formed, when the length of the bulging portion is long or the diameter of the bulging portion is large, it is difficult for the bulging portion to come close to each other, and therefore the bulging portion has a small thickness. As a result, there was a problem in that it was not possible to form a branch pipe having a predetermined wall thickness, resulting in insufficient strength.

In view of the above, an object of the present invention is to provide a method for manufacturing a pipe with a projection that can be formed with a predetermined thickness even for a relatively long branch pipe.

[Structure of Invention]

(Means for Solving the Problems) In order to solve the problems of the above-mentioned conventional technique, the present invention provides a concave pre-deformation in the vicinity of the projection forming portion of the pipe material, and the pipe material in the bulge mold. And a high-pressure fluid is press-fitted into the pipe to bulge the vicinity of the pre-deformed portion to form a protrusion.

(Operation) With the above configuration, since the slack surplus of the portion which is preliminarily pre-deformed when the protrusion of the branch pipe or the like is formed by the bulge processing is drawn into the bulging forming portion, sufficient thickness adjustment is achieved. It is possible to prevent the thickness of the projection portion to be formed from becoming thin, and it is possible to form even a projection such as a long branch pipe without trouble.

(Examples) The present invention will be described below with reference to the examples shown in FIGS. 1 to 8.

As shown in FIG. 1, recessed pre-deformed portions 2, 2 are formed at two locations in the longitudinal direction in the vicinity of the projection forming portion of the pipe material 1 by press working or the like, and the pipe material thus pre-formed As shown in FIG. 3, 1 is housed in the bulge mold 5 so that the remaining portion 3 between the pre-deformation portions 2 and 2 is placed at the position of the protrusion molding die 4, and the bulge die 5 is supplied with pressure fluid. By injecting a pressure fluid (for example, water) from the mouth 6,
The inner surfaces of the pre-deformed portions 2 and 2 and the remaining portion 3 are pressed so that the remaining portion 3 is press-fitted into the protrusion forming mold portion 4 as shown in FIG. 4, and as shown in FIGS. 5 and 6. A pipe-shaped projection 7 is formed on the side surface of the pipe material 1. A branch pipe can be obtained by cutting or piercing the tip of the projection 7.

At the time of forming the protrusion 7, since the pipe material 1 is provided with a sufficient amount of excess thickness (slack) due to the formation of the pre-deformed portions 2 and 2 which are pre-formed, the pipe material 1 is expanded into the protrusion forming mold portion 4. The pre-deformation portions 2, 2 extend and follow during the ejection deformation, and when bulging into the projection molding die portion 4, no galling occurs at the inlet portion thereof, and smooth bulging molding is performed, so that the projection 7
Does not become thin.

In order to further facilitate the molding of the protrusion 7, as shown in FIGS. 7 and 8, a bulge portion 8 is formed on the pipe material 1 by bulging over a required length in the longitudinal direction, and then this bulge portion is formed. If both side portions in the longitudinal direction of 8 are depressed by press working or the like to be pre-deformed into a form similar to that shown in FIG. 1, a surplus portion can be further provided, and the projection 7 can be formed more easily. You can

In the illustrated embodiment, for the sake of convenience of description, the case where the single protrusion 7 is formed on the pipe material 1 is shown, but it is particularly effective when forming a large number of protrusions (branch pipes) such as a manifold. .

〔The invention's effect〕

As described above, the method for producing a pipe with projections of the present invention provides a concave pre-deformation in the vicinity of the projection forming portion of the pipe material, and stores this pipe material in the bulge mold to put it in the pipe. Since a high-pressure fluid was press-fitted to bulge the vicinity of the pre-deformation portion to form a protrusion, when the side surface of the pipe is bulged to form the protrusion, the meat of the pre-deformation portion extends and the protrusion is formed. As a result, smooth lining can be performed, and even if the protrusion is long, the bulging can be performed without reducing the wall thickness.

[Brief description of drawings]

1 to 6 show an embodiment of the present invention. FIG. 1 is a perspective view of a pipe material which is pre-deformed, and FIG. 2 is a cross-sectional view taken at the pre-deformed portion, and FIG. FIG. 4 is a sectional view showing the pipe material of FIG. 1 housed in a bulge mold,
FIG. 7 is a sectional view showing a state after completion of the molding, FIG. 5 is a perspective view of a pipe material after completion of molding of the protrusion, and FIG. 6 is a sectional view cut at the protrusion portion, and FIGS. FIG. 7 shows another embodiment of the present invention. FIG. 7 is a perspective view of a pipe material in which a bulged portion is preformed by bulging, and FIG. 8 is a sectional view cut at the bulged portion. 1 ... Pipe material, 2 ... Pre-deformation part, 3 ... Remaining part, 4 ... Projection forming mold part, 5 ... Bulge mold, 7 ... Projection.

Claims (3)

(57) [Claims] 1. A pipe material is preliminarily deformed in a concave shape in the vicinity of a projection forming portion, the pipe material is housed in a bulge mold, and a high-pressure fluid is press-fitted into the pipe, and the vicinity of the preliminary deformation portion. A method for manufacturing a pipe with protrusions, characterized in that the protrusions are formed by swelling the protrusions. 2. The method for manufacturing a pipe with protrusions according to claim 1, wherein the preliminary deformation in the concave shape is performed by pressing a part of the pipe material. 3. The pre-deformation of the concave shape is performed by temporarily bulging a part of the pipe material by bulging and then denting the bulging portion by pressing. The method for producing a pipe with projection according to item 1.