JPH0617482B2 - Press forming equipment for spirally sintered parts - Google Patents

Description

TECHNICAL FIELD The present invention relates to a press forming apparatus for spiral-wound sintered parts.

[Conventional technology]

Demand for so-called sintered parts obtained by compressing and molding metal powder after compression tends to increase as component parts of automobiles, office machines, home appliances, industrial machinery, etc., and parts with more complicated shapes accordingly. Press molding is required. For example, a spiral part A as shown in FIG. 3 which is used as a pump impeller, a compressor rotor, etc.
Is one.

Conventionally, the spiral part A is an example of which the outer surface shape is adjusted to some extent by casting, and finish cutting is performed by a numerical control (NC) milling machine, etc. Since the cost is large, there is a disadvantage that it takes a long time for processing, which is disadvantageous in terms of cost.

Moreover, since air pockets (so-called cavities) occur in cast products, it is particularly difficult to manufacture thin products and it is necessary to cut out from large lumps, and the defect occurrence rate is high, which is also a factor that increases costs. Become.

Therefore, in order to overcome these drawbacks, manufacture of a sintered spiral wound component by powder metallurgy is being studied, but its implementation was restricted due to the following problems.

[Problems to be solved by the invention]

The problem is that in a metal powder press molding device, a die or a die and a core that form the side wall of the part, and a lower punch that inserts into the die so as to be relatively slidable and forms the end face of the part are essential elements. However, in forming spiral parts,
As shown in the figure, the die 1 and the core 2 are temporarily integrated into a component A.
When attempting to form the side wall of the eddy with this integrated die, there is an excessive amount at the root of the vortex (near the outer edge of the vortex shown by a in the figure) that protrudes due to the large frictional resistance with the part A when the molded product is demolded. That is, the stress is concentrated and the vortex part of the die breaks at that point. Even if a tough material is used for the die, this problem cannot be avoided if the thickness of the vortex portion of the die, that is, the dimension H in the figure is limited to a small value.

On the other hand, if a method is adopted in which the core 2 is divided from the die 1 and is supported by a plate to avoid the above-mentioned problem, the support of the lower punch having the same end-view shape as that of the component A that needs to be arranged below the die is required. The core support plate hinders it, making it impossible to perform press molding. Press molding is possible if the divided core 2 is integrated with the lower punch, but the core and the lower punch must be movable relative to each other in the pressing direction of the lower punch, or the molded product can be demolded. It is not possible to take such a method because it is not possible.

It is an object of the present invention to provide a press-molding apparatus for spiral-wound sintered parts that does not cause these problems.

[Means for solving problems]

The press forming apparatus of the present invention that achieves the above-mentioned object includes a die having a die hole for forming a side wall of a spiral part and a spiral lower part for slidably inserting into the die to form an end face of the part. In a press-molding apparatus for a sintered part equipped with a punch, a spiral core portion existing between vortices of the mold cavity is divided from a die, and a plurality of rods are displaced in the spiral direction in the divided cores. Is attached in the pressing direction, each rod is inserted through the lower punch and its supporting plate, and is supported by the core supporting plate arranged below the lower punch supporting plate.

That is, it is possible to divide the core part from the die by supporting the core part with a rod that penetrates the part of the lower punch that avoids the forming vortex part, and to press the lower punch and the core for die cutting. The relative slide in the direction is also free.

〔Example〕

An example of the apparatus of the present invention is shown in the attached FIGS. 1 and 2. FIG. 1 is a plan view of the die 1 and the spiral core 2, and FIG. 2 is a vertical cross-sectional view of a main part of the apparatus including the upper punch 3 and the lower punch 4.

The die 1 supported by the die plate 5 is provided with a shaped hole 1a similar to the outer surface contour of the outermost vortex of the part A, in which the core 2 divided from the die forms the outer end surface of the vortex. It is set in close contact with the non-molding surface 1b existing on the stepped portion of the hole 1a. Upper punch 3 for molding the upper surface of part A in the figure
The lower punch 4 for molding the lower surface and the lower surface has the same spiral shape as the shape of the part A in plan view. The upper punch 3 is an upper ram (not shown), while the lower punch 4 is a base plate 6
Driven vertically by lower rams (also not shown) via. The lower punch 4 may be fixed at a fixed position by propelling the die 1 in the vertical direction.

A plurality of connecting rods 7 whose positions are changed in the vortex winding direction are connected to the lower surface of the split core 2 that forms the part side wall surface of the part that does not follow the mold cavity 1a. As shown in FIG. 2, one end of this rod extends vertically between the die vortices of the lower punch and loosely penetrates through a hole provided in correspondence with the base portion of the core and the plate 6 to extend below the base plate 6. It is connected to the arranged core support plate 8, and the core 2 is held in a fixed position via this rod.

In the above apparatus, the upper punch 3 is located at the top dead center above the solid line position in FIG. 2 at the start of pressing, and the die 1, the core 2, and the lower punch 4 are formed between the three members. A metal powder, which is a molding material, is filled in the space. Then, the filled metal powder is compressed by the descending upper punch 3 and shaped into a predetermined shape.

After the molding, the die plate 5 and the base plate 6 supporting the lower punch 3 are relatively brought close to each other and the part A is die-cut, but after the operation is finished, the core 2 is pulled down or the core and the lower punch are once held at the same time. When lifted, the frictional resistance between the molding die and the part A decreases, which facilitates die cutting.
It is also difficult for the parts to lose their shape.

The dividing point of the core 2 from the die may slightly enter the inner end side of the vortex from the position shown in the drawing.

Further, the spiral of the component A may have a winding angle of 720 ° or less, but the present invention is particularly suitable for press molding of a component having a spiral of 720 ° or more.

In addition, when the vortex winding angle is large, the core 2 is about 36
It is desirable to further subdivide into a vortex of 0 ° or less. For example, in the case of the illustrated core, if the cores are further divided at the position indicated by the chain line in FIG. 1 and each core is attached to a separate core support plate, each of the divided cores is timed when the cores are relatively lowered during die cutting. By shifting and pulling down, the pulling down resistance per core can be reduced, which is also useful for improving the mold release property of the molded product and preventing the shape collapse. Also, the core can be easily manufactured.

[Effect]

As described above, according to the present invention, since the spiral core is divided from the die and is supported by the plate disposed below the lower punch via the rod penetrating the lower punch and the supporting plate, the spiral core is supported. Mass production of sintered parts with high efficiency becomes possible, and the cost of parts can be reduced.

Note that the molding apparatus of the present invention exerts the best effect in press molding of powder material, but also exhibits the same effect when used for sizing of sintered parts, forging, and the like.

[Brief description of drawings]

FIG. 1 is a plan view of a die and a core of an embodiment of the press molding apparatus of the present invention, and FIG. 2 is a vertical sectional front view showing a main part of the apparatus,
FIG. 3 is a perspective view of the spiral part, and FIG. 4 is a plan view of a conventionally considered die. 1 ... Die, 2 ... Split core, 3 ... Upper punch, 4 ...
Lower punch, 5 ... Die support plate, 6 ... Base plate, 7 ... Connecting rod, 8 ... Core support plate

Claims (3)

[Claims] 1. A sintered part comprising a die having a mold cavity for forming the side wall of the spiral part and a spiral lower punch for slidably inserting into the die to form the end face of the part. In the press molding apparatus, the spiral core portion existing between the vortices of the mold cavity is divided from the die, and a plurality of rods displaced in the spiral winding direction are attached to the divided cores in the pressing direction. An apparatus for press-forming a spiral-shaped sintered component, wherein each rod is inserted through a lower punch and its supporting plate and is supported by a core supporting plate arranged below the lower punch supporting plate. 2. The core part is divided into a plurality of vortices of 360 ° or less, and each of the split cores is supported by the rod. Press forming equipment for spirally sintered parts. 3. The press molding of the spiral-shaped sintered component according to claim 1, wherein the spiral of the core portion is a spiral of 720 ° or more. apparatus.