JPH0337815B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method most suitable for manufacturing a metal product integrally holding a tube body, particularly a thin-walled tube body.

Conventionally, when manufacturing a metal product that has a tubular part as part of the structure of the product, a pipe and a connecting member to be combined with the pipe and integrated are prepared separately in advance, and the connecting member side is By press-fitting a pipe into a protrusion or hole, welding the joints of the two together, or fixing them with fixing devices such as pins or screws,
The pipe and its connecting members are integrated into a product.

However, with these methods, especially when the pipe forming the tubular part of the product is thin, the pipe may be damaged or deformed at the joint, making it difficult to integrate. In addition to being time consuming to process, it is difficult to obtain uniform strength at the joint, and the appearance is unsightly.

Structure of the Invention The present invention has been made in response to the above-mentioned circumstances, and its gist is that when manufacturing a metal product that has a tube as a part of the structure of the product to be manufactured, When the connecting member and the tube body to be converted are prepared in advance as separate members, and the connecting member is machined to fit with the tube body and the two are combined, or when the connecting member is manufactured by casting. , store the tube body in the casting mold,
By pouring the molten metal into this casting mold, the joint parts of the two are fitted and combined, thereby pre-bonding the tube body and its coupling member, and by subjecting this pre-bond body to forging, the tube The fitting part of the body and its connecting member is deformed and crimped to obtain a product in which the body and the connecting member are integrated firmly and aesthetically.

Examples will be described in detail below with reference to the drawings.

Figure 1 shows that when manufacturing a connecting member to be integrated with a tube body by casting, the tube body and the connecting member are pre-bonded using the casting process and then subjected to a forging process. This shows the case where finishing molding is performed.

In Figure 1-A, lower mold 11 and upper mold 1 for casting
2, in advance, a cylindrical hollow part matching the diameter of the tubular body 2 that forms a part of the target product, and a connecting member to be integrated with the tubular body 2 in a state that communicates with this hollow part. A hollow portion 10 is formed in advance. The tube body 2 is housed in a predetermined position in such casting molds 11 and 12. At this time, the inner plug 3 is fitted into the pipe body 2 so that the molten metal does not flow into the pipe body 2 more than necessary. The inner stopper 3 consists of a fitting part 3a into the tube body 2 and a protruding part 3c having the same diameter as the tube body 2, but the tip 3b of the fitting part 3a
is from the end 2a of the tube body 2 on the hollow part 10 side,
The molten metal may partially flow into the tube 2 by drawing it slightly into the tube 2, so that the vicinity of the end of the tube 2 is sandwiched from both sides by the molten metal. desirable. This is particularly important if the tube end 2 is a thin-walled tube. Since the inner stopper 3 is used to define the limit range for the molten metal to reach into the pipe body, it does not necessarily have to be a stepped rod with different diameters as shown in the figure. Any structure that can prevent the movement of the material is sufficient. 13 is a sprue, and 14 is a runner.

In this state, a molten metal, for example, an aluminum alloy, is poured from the sprue 14 and solidified, the molded product is taken out of the mold, the inner plug 3 is pulled out, and a deburring process is performed.
A casting of the coupling member 1 that fits and holds the tube body 2 as shown in FIG.

The pre-bonded body 5 of the tubular body 2 and the coupling member 1 thus obtained is combined with a lower die 16 for forging manufactured according to the dimensions of the target product, and an upper die of the same shape as the lower die (Fig. (not shown) are attached to a forging machine, and are forged until the desired finished shape is achieved. In FIG. 1-C, the abutting portion 17 of the forging die to the tubular body 2 is manufactured to be equal to the diameter of the tubular body 2, and the tubular body 2 is not subjected to pressing force by the forging die. In the process of such forging, the metal flows in the radial and axial directions of the connecting member 1, and the metal flows into the desired shape, and the metal structure becomes fine and homogeneous, so that the tube body and the connecting member are bonded together. At the same time that the joining surfaces of the tube body and the coupling member 1 fit into each other, the pressure applied to the coupling member 1 is also applied to the tube body through the metal structure, so that the tube body itself Also, changes in the metal structure and deformation of the shape 2b occur, and therefore, at the bonding boundary between the two, the two metals are intricately intertwined and crimped.
Strong integration is achieved. This crimping and integration of the tube body and its connecting member by forging is more effective if hot forging is used as the forging process.

Also, near the end of the tube, as shown in Figure 2,
By providing a plurality of holes 2c or recesses, or by adding deformation as shown in FIG. 3, the metal will wrap around these holes or deformed parts during forging, improving adhesion.

Furthermore, when manufacturing a product in which coupling members are integrally coupled to both sides of the tube body 2, a pull-out type inner stopper as shown in FIG. 1 is not used. In this case, an inner plug is used that can be attached to the tube body 2 and fixed in that position. Such things include, for example:
As shown in FIG. 4, the truncated conical inner plugs 7, 7 are placed with their large diameter side facing the inside of the tube, and with the largest diameter portion 7a retracted slightly from the end of the tube. It is fixed by pressing against the inner peripheral surface of the tube. The molten metal is pipe body 2
It enters the pipe from both sides of the inner plug 7, reaches near the maximum diameter portion 7a along the tapered surface 7b of the inner plug 7, and is then cooled and solidified to hold and fix the inner plug 7. Inside stopper 7 like this
can also be used in place of the inner stopper 3 in the embodiment shown in FIG.

The shape of the inner stopper of the type that is installed in the tube and integrated with the target product is not necessarily limited to one having a tapered surface. Any suitable material, such as one having a small diameter portion nearby, can be adopted.

In FIG. 5, a coupling member 21 is made in advance by machining such as cutting, casting, or forging, a tube body 22 is preliminarily coupled to this, and then,
This figure shows an example method of subjecting this pre-bonded body to a forging process. In this case, in order to fit and pre-bond the tube body 22 to the coupling member 21 which has been manufactured by an optimal manufacturing method according to its shape, first, the coupling member 21 must be drilled, etc. A fitting hole 23 is formed by performing necessary processing. The tubular body 22 is inserted into this and preliminary bonded.

Forging this pre-bonded body 20 using a forging die as shown in FIG. In order for the two to be effectively crimped at the fitting portion of It is desirable that the core 24 be inserted into the tube 22 over the region of overlap between the tube and the coupling member so that it is not damped by directional deformation. This is particularly important when the tube body 22 is thin. The center core may be in the shape of a round bar, but the center small diameter portion 2 shown in FIG.
4a, between the inner peripheral surface of the tube body 22 and the center core,
If the shape is determined so that some voids remain, plastic deformation of the tube and wrapping of the metal of the connecting member will occur during forging, which will increase the crimping effect between the tube and the connecting member and increase the The core is also fixed in position with sufficient strength.

Of course, the material of the core and the inner stopper may be the same material as the coupling member and the pipe body, or may be a different material.

Effects According to the method of the present invention, in the manufacture of parts having a pipe as a part of the structure, the two can be integrated with sufficient strength, and the appearance is similar to that of screws. Unlike welding or welding, unnatural unevenness does not occur on the product.

In particular, when the pipe body is small in diameter or thin-walled, conventional methods such as press-fitting, welding, screwing, etc. may cause deformation of the pipe body or the joint between the two members. However, according to the method of the present application, products that have small-diameter or thin-walled pipes as part of their structure can be manufactured using the method of this application. It is possible to inexpensively mass-produce products that are homogeneous, have sufficient strength, and have a cohesive appearance.

[Brief explanation of the drawing]

FIGS. 1A to 1E are explanatory diagrams showing steps of a method according to an embodiment of the present invention. FIGS. 2 and 3 are explanatory diagrams showing examples of preliminary processing of a tube body used in the method of the present application, respectively. FIG. 4 is an explanatory diagram showing the main part of another embodiment of the method according to the present invention. FIGS. 5A to 5C are explanatory diagrams showing essential parts of still another embodiment of the method of the present invention.

Claims (1)

[Scope of Claims] 1. When manufacturing a metal product having a tube as part of its structure, the tube is stored in advance in a casting mold for making a coupling member to be integrated with the tube,
After pouring the molten metal into the casting mold to obtain a casting of the coupling member that fits and holds the pipe body, the casting is forged with a forging die having a predetermined finished shape to obtain the finishing. A method for manufacturing a metal product having a tubular part, characterized in that the tubular body and the coupling member are integrated by pressure bonding by deforming the tubular body into a shape. 2. When manufacturing a metal product having a thin-walled tube as a part of the structure, a fitting hole is formed in the coupling member to be integrated with the tube as a fitting part with the tube, and the tube and the tube are connected together. After fitting the connecting member and storing the core in the tube over the overlapping region of the tube and the connecting member, the connecting member is forged to be transformed into a predetermined finished shape. A method for manufacturing a metal product having a thin-walled tubular portion, characterized in that the tubular body and its coupling member are integrated by pressure bonding.