JP4089046B2 - Pipe welding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for welding cylindrical pipes, and particularly to a method for welding materials having different heat capacities.
[0002]
[Prior art]
When welding materials having different heat capacities, if a material that sufficiently melts a material having a large heat capacity is used, the material having a small heat capacity is melted too much, making it difficult to perform good welding. If it is performed under conditions that do not melt too much, there is a problem that a material having a large heat capacity does not melt sufficiently and it becomes difficult to perform good welding.
[0003]
As a conventional technique for solving the above problem, there is JP-A-53-129135. This publication discloses a welding method in which a metal plate having a small heat capacity is pressed onto a material having a small heat capacity and then a material having a small heat capacity is brought into close contact with the material having a large heat capacity for welding. Is disclosed, welding of materials having different heat capacities can be easily performed, and reliable welding can be performed quickly.
[0004]
[Problems to be solved by the invention]
However, in the above prior art, materials having different heat capacities can be easily welded. However, since the materials are adhered by pressing down a metal pad, the materials cannot be adhered depending on the shape of the material. Welding becomes difficult. For example, when a pipe-shaped material is inserted into the inner periphery of the mounted member and the pipe-shaped material is welded to the mounted member, the outer diameter of the pipe is smaller than the inner diameter of the hole of the mounted member in order to insert the pipe. Since it is designed, even if the contact metal has a shape along the inner peripheral surface of the pipe, the entire outer peripheral surface of the pipe cannot be in close contact with the contact by the contact metal, and it is difficult to perform good welding.
[0005]
In view of the above, an object of the present invention is to provide a welding method capable of reliably welding a pipe-shaped material and a material having different heat capacities in order to solve the above problems.
[0006]
[Means for Solving the Problems]
A welding method in which one end of a cylindrical pipe is welded to the inner peripheral surface of a mounting hole provided in a flange made of a material having a different heat capacity from that of the pipe, and the inner peripheral surface of the mounting hole is directed radially inward. A projecting part consisting of a corner part projecting is formed over the entire inner peripheral surface, and after inserting one end of the pipe into the mounting hole, the pipe diameter is increased and the outer periphery of the pipe is extended by the projecting part. The pipe is attached to the flange while maintaining airtightness by a pipe expanding process in which the pipe and the flange are arc-welded after the pipe expanding process, and a pipe expanding process in which the pipe and the flange are arc-welded after the plastic expanding process. I did it.
[0007]
According to the first aspect, since the pipe can be brought into close contact with the hole of the flange by the pipe expanding process, the heat conduction is performed between the pipe and the flange in the process of welding the pipe and the flange made of materials having different heat capacities. This makes it possible to weld the pipe and the flange well. Further, when the pipe is expanded, the outer peripheral surface of the pipe is caught by the projecting portion and is plastically deformed, so that the close contact with the mounting hole of the pipe becomes strong, and welding in the welding process can be performed satisfactorily.
[0010]
According to the second aspect of the present invention, in the tube expanding step, the outer periphery of the pipe and the inner periphery of the mounting hole are brought into close contact with each other at a position that has entered the mounting hole in the axial direction from the end surface of the mounting hole.
[0011]
According to the second aspect , even when a force in a direction different from the axial center of the pipe is applied to the pipe, the pipe is difficult to be detached from the mounting hole.
[0012]
The invention of claim 3 is that, in claim 2, the flange is formed by casting, and the projecting portion is constituted by a partition line surface or a mold dividing surface formed on the mold dividing surface of the flange.
[0013]
According to the third aspect, since the pipe is locked using the partition line surface or the mold dividing surface, it is not necessary to cut the partition line surface or the mold dividing surface after dividing the flange. Is preferred.
[0014]
According to a fourth aspect of the present invention, the protruding portion has a flat surface extending radially inward from the inner peripheral surface of the mounting hole, and the mounting hole having a diameter extending from one to the other in the thickness direction of the flange. And the corner portion is formed by an intersection of the plane and the slope.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a state after the pipe 1 and the flange 2 are welded in the present embodiment. In this embodiment, a case where one end of an intake manifold of an engine is welded will be described.
[0017]
The materials used in this embodiment will be described. The flange 2 is made of an aluminum die-cast ADC12 (thickness 20 mm), and the pipe 1 is made of an aluminum pipe 1A3003 (thickness 2.0 mm).
[0018]
The intake manifold is formed by attaching the pipe 1 having a long cross-sectional shape and a hollow pipe 1 to the flange 2 after being bent into a desired shape in advance.
[0019]
The welding method in the present embodiment includes a pipe expanding step in which one end of the pipe 1 is inserted into the mounting hole 3 and then the pipe diameter of the pipe 1 is expanded to bring the outer peripheral surface of the pipe 1 into close contact with the inner periphery of the mounting hole 3. The inner circumference of the mounting hole 3 provided in the flange 2 made of a material having a heat capacity different from that of the pipe 1 by a welding process in which the pipe 1 and the flange 2 are arc-welded after the pipe expansion process. To be welded.
[0020]
Each step will be further described. FIG. 2 is a cross-sectional view showing the pipe expansion process. In the pipe expansion process, the pipe 1 is inserted into the mounting hole 3 of the flange 2 and the pipe expander 4 is inserted into the inner periphery of the pipe 1 to expand the pipe 1. The pipe expander 4 divides a column having a long hole shape smaller than the inner diameter of the pipe 1 into four members 4a and a central axis 4b in the circumferential direction, and moves the central axis 4b of the pipe expander 4 downward in the drawing. Each of the four members 4a divided by this is configured to expand in the radial direction. The pipe 1 is expanded by such movement of the central shaft 4b, and the inner periphery of the mounting hole 3 and the outer periphery of the pipe 1 are brought into close contact with each other. In the present embodiment, the end fitting jig 5 is installed in the mounting hole 3 so that the end face of the pipe 1 is in close contact with the mounting hole 3 at a predetermined position during the pipe expansion process, so that the pipe 1 has a predetermined distance or more. It is restricted so as not to enter the mounting hole 3.
[0021]
In the present embodiment, the flange 2 is formed by casting, and a partition line 3a is generated over the entire circumference of the mounting hole 3 by dividing the mold. The partition line 3a is formed by using the partition line 3a as a protrusion. Since the outer peripheral surface of the pipe 1 is brought into close contact with the pipe 1, the close contact between the pipe 1 and the flange 2 is strengthened, and a cutting process for eliminating the partition line 3a is also unnecessary. In addition, provisional welding for temporarily fixing the parts before welding is not required.
[0022]
The welding process will be described. In the state after the pipe expansion process shown in FIG. 3, the outer periphery of the pipe 1 and the inner periphery of the mounting hole 3 are in close contact with each other without a substantial gap, so that it can be joined relatively easily even in TIG welding that is severe with respect to the clearance. it can.
[0023]
As mentioned above, although embodiment of the present invention was described using an intake manifold of an engine, the present invention is not limited to the above-mentioned embodiment, and is a pipe welding method according to the gist of the present invention. Any welding method may be used.
[0024]
【The invention's effect】
According to the first aspect, since the pipe can be brought into close contact with the hole of the flange by the pipe expanding process, the pipe and the flange can be favorably welded in the process of welding the pipe and the flange made of materials having different heat capacities. It becomes possible.
[0025]
According to the second aspect, the pipe can be easily bent by forming the pipe with a material having a small heat capacity, and the degree of freedom in designing the pipe to be attached is improved.
[0026]
According to the third aspect, even when a force in a direction different from the axis of the pipe is applied to the pipe, the pipe is unlikely to be detached from the mounting hole, and the rigidity is improved.
[0027]
According to claim 4, when the pipe is expanded, the outer peripheral surface of the pipe is caught by the protruding portion, so that the close contact with the mounting hole of the pipe becomes strong, and welding in the welding process can be performed satisfactorily.
[0028]
According to the fifth aspect, since the pipe is locked by plastic deformation using the partition line surface or the mold dividing surface, it is not necessary to cut the partition line surface or the mold dividing surface after dividing the flange, and the number of manufacturing steps is reduced. From the viewpoint of
[Brief description of the drawings]
FIG. 1 is a diagram showing a state after welding of a pipe and a flange in an embodiment of the present invention.
FIG. 2 is a diagram showing a tube expansion process in the present embodiment.
FIG. 3 is a diagram showing a state after a tube expansion process in the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Pipe 2 ... Flange 3 ... Mounting hole 4 ... Tube expansion machine 5 ... Jig for terminal alignment
6 ... Corner

Claims (4)

A welding method for welding one end of a cylindrical pipe to an inner peripheral surface of a mounting hole provided in a flange made of a material having a different heat capacity from the pipe,
On the inner peripheral surface of the mounting hole, a projecting portion consisting of a corner projecting radially inward is formed over the entire inner peripheral surface,
One end of the pipe is inserted into the mounting hole, and then the pipe diameter is increased, and the outer periphery of the pipe is plastically deformed and hooked by the protruding portion, thereby closely contacting the inner peripheral surface of the mounting hole. Tube expansion process,
A pipe welding method including a welding step of arc welding the pipe and the flange after the pipe expansion step.   2. The pipe welding method according to claim 1, wherein in the pipe expanding step, the outer peripheral surface of the pipe and the inner periphery of the mounting hole are brought into close contact with each other at a position where the pipe enters the mounting hole at a predetermined distance from the end surface of the mounting hole.   2. The pipe welding method according to claim 1, wherein the flange is formed by casting, and the projecting portion is constituted by a partition line or a mold dividing surface formed on a mold dividing surface of the flange. The protrusion is a plane extending radially inward from the inner peripheral surface of the mounting hole;
A slope that narrows the mounting hole radially inward from one side to the other in the thickness direction of the flange,
2. The pipe welding method according to claim 1, wherein the corner is formed by an intersection of the plane and the slope.

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