JPH02165838A - Forming method for composite cylindrical parts - Google Patents

Abstract

PURPOSE:To obtain duplex cylindrical parts having high dimension accuracy without employing especially a joining means by providing a through-hole on the axis center of a duplex billet formed by fitting a billet made of an inner layer material into a bottomed and cylindrical billet made of an outer layer material, extruding the duplex billet by extrusion and bringing it to diffusion joining. CONSTITUTION:By fitting internally a columnar billet 2 into a bottomed and cylindrical billet 1, a duplex billet 3 is formed. On the axis center of the duplex billet 3, a through-hole into which a core axis is inserted is provided. Subsequently, in an indirect extrusion die 6, the duplex billet 3 is loaded so that its bottom part side becomes an extrusion port 7 side. To a seal block 10, the core shaft 4 is attached, and the core shaft 4 is inserted through the through-hole 5 of the duplex billet. By bringing a die body 8 to rolling reduction by a stem platen 11, the duplex billet 3 is extruded. The inner and the outer billets 1, 2 are formed to a duplex pipe 12, while being brought to diffusion joining.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for molding a composite cylindrical part whose inner and outer layers are made of different materials.

(Prior Art) Conventionally, in order to mold a composite cylindrical part, an inner layer part and an outer layer part are individually molded, and then the two parts are fitted together using an adhesive.
It was a press fit.

(Problem to be solved by the invention) Molding the inner and outer layers separately requires many steps and increases costs;
Additionally, relative dimensional errors also increase.

Furthermore, when the inner and outer layers are fitted together using an adhesive, the adhesive force may be insufficient, the gap between the two may become eccentric, or the adhesive vapor may have an adverse effect. Furthermore, when the inner and outer layers are press-fitted, there is a problem in that distortion occurs due to residual stress.

The present invention aims to solve the above problems.

(Means for Solving the Problems) A feature of the present invention is that when extruding a composite cylindrical part 17 whose inner and outer layers are made of different materials, first, a bottomed cylindrical billet 1 made of the outer layer material is , a billet 2 made of inner layer material is inserted to form a composite billet 3, and this composite billet 3
A through hole 5 is provided in the axis of the composite billet 3 into an extrusion mold 6.
At the same time, the core shaft 4 is inserted into the through hole 5, and the composite billet 3 is extruded from the extrusion lower, thereby diffusion bonding the inner and outer billets 1.2 and forming the composite billet. formed into a pipe 12, and then this composite pipe 1
2 is cut to a certain length and then die-forged to form a composite cylindrical part 1.
It is at the point where it is formed into 7.

(Function) According to the method of the present invention, the inner and outer layers of the composite pipe are simultaneously extruded in one step, and the inner and outer layers are joined by diffusion bonding while being extruded.

The inner and outer layers of such a cylindrical product, which is made by cutting a composite pipe to a certain length and die-forging it, are bonded by diffusion bonding, so there is no need for an adhesive, and there is a risk that gaps or residual stress may occur between the inner and outer layers. do not have. Furthermore, since the molding is performed after the inner and outer layers are joined, there is no relative dimensional error.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

First, a cylindrical billet 1 with a bottom as shown in FIG.
A cylindrical billet 2 is fitted inside to form a composite billet 3. At this time, a gap of about 0.1 mm is created between the inner circumferential surface of the outer billet 1 and the outer circumferential surface of the inner billet 2.

In this embodiment, the outer layer billet 1 is made of N alloy A606.
1 and molded by cold compression.

In this embodiment, the material of the inner billet 2 is stainless steel 5.
US416 and molded by cold compression.

Next, a through hole 5 is provided in the axial center of the composite billet 3, into which a core shaft 4, which will be described later, is inserted. In this example, the through hole 5 was provided by machining.

Then, as shown in FIG. 3, the composite billet 3 is loaded into the mold 6 for indirect extrusion so that the bottom side of the billet is on the extrusion lower side. Here, the molding die 6 includes a goo body 8 having an extrusion lower, a cylindrical molding container 9 surrounding this, and a seal block 10 closing the lower end of this molding container 9.
The stem platen 11 is operatively connected to a pressing mechanism (not shown).

Then, the core shaft 4 is attached to the seal block 10, and the core shaft 4 is inserted into the through hole 5 of the composite billet 3.

Thereafter, the goo body 8 is pushed down by the stem platen 11 to extrude the composite billet 3 from the extrusion lower. As a result, the inner and outer billets 1.2 are diffusion bonded, while the composite round pipe 1 whose outer layer is made of N alloy and whose inner layer is made of stainless steel.
It is formed into 2. Here, the extrusion temperature is 480°C,
The extrusion ratio was 10-30°C.

The composite pipe 12 is then cut to a certain length as shown in FIG. 4, and then die forged as shown in FIG. The forging device mainly includes a die 13, a bunch 14 interlocked with a pressing mechanism (not shown), and a knock pin 15.
By pressing down the bunch 14 from the left side in FIG. 5 to the right side, it is formed into a cylindrical part 17 having a flange 16 on the outer layer as shown in FIG. 6. In this embodiment, this cylindrical part 17 is further machined to form a hub 18 that also serves as a rotor for a hard disk drive motor for office automation equipment as shown in FIG. Discs can be installed.

Note that the material of the composite cylindrical part is not limited to the above embodiments,
Further, the shape is not limited to a round part, and may be a square cylinder. Furthermore, not only indirect extrusion but also direct extrusion may be used.

Furthermore, the method of forming the inner and outer billets is not particularly limited, and the shapes may be square cylinders, prisms, etc., and the through holes may be formed at the same time as billet forming.

(Effects of the Invention) According to the present invention, the inner and outer layers of a composite pipe can be extruded at the same time without being extruded separately, and the inner and outer layers are diffusion bonded simultaneously with extrusion, so there is no need to provide a separate bonding method. do not have. Since a composite cylindrical part is obtained by die forging this composite pipe, manufacturing costs are reduced by shortening the manufacturing process, and the inner and outer layers are bonded by diffusion bonding, so there is no gap between the inner and outer layers. Further, since the inner and outer layers are molded after being fitted, the relative dimensional error between the inner and outer layers can be reduced to a minimum, and a component with high dimensional accuracy can be obtained. Of course, there is no need for adhesive for joining the inner and outer layers, there is no adverse effect from adhesive vapor, and no distortion occurs due to residual stress when press-fitted.

[Brief explanation of the drawing]

The drawings relate to embodiments of the present invention; FIG. 1 is a sectional view of a composite billet, FIG. 2 is a sectional view of a composite billet provided with through holes,
Figure 3 is a sectional view of the mold, Figure 4 is a sectional view of the composite pipe, Figure 5 is a sectional view of the forging device, Figure 6 is a sectional view of the composite cylindrical part, and Figure 7 is also used as the rotor of the motor. FIG. 3 is a cross-sectional view of the hub. 1... Outer layer billet, 2... Inner layer billet, 3...
・Composite billet, 4... Core shaft, 5... Through hole, 6.
... Molding die, 7... Extrusion port, 12... Composite pipe,
17...Cylindrical composite part.

Claims (1)

[Claims] (1) Composite cylindrical part whose inner and outer layers are made of different materials (17)
When extrusion molding, first, a billet made of an inner layer material (2) is fitted into a bottomed cylindrical billet made of an outer layer material (1) to form a composite billet (3), and the composite billet (3) is A through hole (5) is provided in the axial center, and the composite billet (3) is loaded into the extrusion mold (6) with the bottom side facing the extrusion port (7), and the core is inserted into the through hole (5). Insert the shaft (4),
By extruding the composite billet (3) from the extrusion port (7), the inner and outer billets (1) and (2) are diffusion bonded and formed into a composite pipe (12), and then this composite pipe (12) is cut into a certain length. Composite cylindrical parts (17) are made by cutting and die forging.
A method for forming a composite cylindrical part, which is characterized by forming a composite cylindrical part.