JPH09194904A - Manufacturing equipment for powder compacts - Google Patents

Abstract

(57) An object of the present invention is to prevent a decrease in the density of raw material powder around the center hole when, for example, compacting metal powder to form a gear material. SOLUTION: A center core 3 for forming a vertical hole is arranged in a recess space P formed by a die 1a of a lower die 1 and a lower punch 1b to fill a raw material powder G, and then the center core 3 is raised. When the raw material powder G is pressed by the upper punch 2 to powder-mold the gear material W having the center hole c, the core chip 3a that is detachably attached to the upper end of the center core 3
Is attached, and the peripheral edge of the upper end of the core chip 3a is formed as an inclined surface t which is inclined downward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for increasing the strength around a center hole, for example, when a gear product having a center hole is manufactured by compacting and sintering metal powder. .

[0002]

2. Description of the Related Art Conventionally, parts such as gear parts which are required to have wear resistance and toughness have been manufactured by powder compacting. In such a powder compacting method, in a recess space of a die, The raw material powder is filled in, and the powder is pressed by a punch to sinter a powder compact molded into a gear shape to be manufactured. In addition, for example, when forming a hole in the center of a gear product, the core is faced to the central portion in the recessed space of the die and the raw material powder is filled. The core is made to have a hole by being positioned higher than the upper surface and pressing a predetermined portion other than the core portion with a punch to perform powder compaction.

[0003]

However, in the above method, when the upper surface of the core 51 is raised to a height higher than the upper surface of the raw material powder G, as shown in FIG.
(1) The peripheral raw material powder G is wiped off at the peripheral portion of the upper surface, and the density of the raw material powder G at the peripheral portion of the hole becomes thin, so that the strength of the portion is reduced when the powder is compacted by the upper punch 52. was there. When forming a center hole with such a core 51, if the center hole is, for example, a place where a rotary shaft is press-fitted, especially in the case of a gear with a helical tooth in which an eccentric load is easily applied to the center of the gear, the hole periphery There is a problem that the part is easily damaged, and the center hole is likely to be missing if the center hole is, for example, an internal tooth.

Therefore, there has been a demand for a technique for preventing a decrease in the density of the raw material powder so as not to cause a decrease in the strength of the peripheral portion of the hole when forming a hole using such a core 51.

[0005]

In order to solve the above-mentioned problems, the present invention is characterized in that, in claim 1, raw material powder is filled with a core for forming a vertical hole provided in a recess space and the core part is removed. In a manufacturing apparatus in which other predetermined parts are pressed by an upper punch to manufacture a powder compact, the core is vertically movable, and the upper peripheral edge of the core is formed as an inclined surface which is inclined downward.

Then, for example, when filling the raw material powder, the upper surface of the core is adjusted to the height of the upper surface of the recessed space, and after filling, the core is lifted to make the upper surface higher than the upper surface of the raw material powder. Next, other predetermined portions except the core portion are pressed by the upper punch to form vertical holes penetrating in the vertical direction in the powder compact, but when the core was raised, it was deposited on the inclined surface of the upper peripheral edge portion. The raw material powder falls downward along the inclined surface,
The powder density around the core becomes thicker and the strength increases.

In the second aspect, the upper end portion of the core, which includes at least the inclined surface, can be replaced. That is, since the slipperiness varies depending on the type and particle size of the raw material powder, the upper end portion having the optimum sliding angle is replaced depending on the type and the particle size of the raw material powder. Further, in claim 3,
Such a powder compact is used as a gear material, and a core is used to open a center hole of the gear material.

[0008]

Embodiments of the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 is an explanatory view for explaining a pressed state of the upper punch and an extruded state of the lower die, FIGS. 2 to 5 are process diagrams showing a process of powder compacting, and FIG. 6 is an example of a powder compact. It is explanatory drawing of a gear material. The apparatus for producing a powder compact according to the present invention is configured as an apparatus for compacting a gear material W as shown in FIG. 6, for example.
A center hole c for press-fitting the rotary shaft is formed in the center, and a side hole s for weight reduction and the like is formed on the outside thereof.
A plurality of ... Is formed.

Of the center hole c and the side holes s, the hole peripheral portion of the center hole c is required to have strength, and the manufacturing apparatus of the present invention improves the strength of the peripheral portion of the center hole c. I am trying.

That is, as shown in FIG. 1, this apparatus comprises a lower die 1 as a lower die and an upper punch 2, and the lower die 1 is composed of a die 1a and a lower punch 1b. The lower punch 1b can be moved up and down along a through hole H provided at the center of the die 1a, and at the lowered position, a recess space P (FIG. 2) is formed in the upper portion of the through hole H and the lower punch 1b is moved up. The concave space P is eliminated at the position (FIG. 1).

The lower punch 1b is provided with a center core 3 for forming a center hole c of the gear material W and side cores 4, ... For forming side holes s ,. , The lower ends of the side core rods 5 connected below the side cores 4, ... Are connected to the lifting cylinder 6. The main body of the lifting cylinder 6 is movable up and down by a hydraulic cylinder unit (not shown), and the upper surfaces of the side cores 4, ... Are made to project upward from the upper surface of the lower punch 1b as the lifting cylinder 6 moves up and down. ing.

The lower end of the center core rod 7 connected to the lower side of the center core 3 is connected to a piston 8 inside the lifting cylinder 6, and the piston 8 is driven by the air pressure introduced into the lifting cylinder 6. I try to move up and down. In order to regulate the vertical stroke, a stopper member 11 is fixed to the upper part of the lifting cylinder 6 via a spacer 10, and a large-diameter upper end portion 7a of the center core rod 7 is attached to a flange portion 11a of the stopper member 11. Are brought into contact with each other to regulate the rising position of the center core 3.

Further, a spacer 1 is provided between the side cores 4, ... And the side core rods 5 ,.
2, ... are interposed so that the amount of protrusion of the side cores 4 ,.
A spacer 13 is also provided between the center core rod 7 and the center core rod 7 so that the upward protrusion amount of the center cores 4, ... Can be adjusted.

On the upper part of the center core 3, as shown in FIG. 7 which is an enlarged sectional view of the same, a detachable core chip 3a is attached by a bolt 14. Further, the core chip 3a has an inclined surface t whose outer peripheral edge portion is downwardly downward, and is tapered toward the upper side. Incidentally, as the core chip 3a, several kinds of core chips 3a having different inclined angles of the inclined surface t are prepared so that they can be easily replaced.

The upper punch 2 shown in FIG. 1 is movable up and down with respect to the lower die 1. An escape hole 15 into which the upper end of the center core 3 can be inserted is provided in the center of the lower surface of the upper punch 2, and an escape hole into which the upper ends of the side cores 4, ... Can be inserted around the escape hole 15. Holes 16, ... Are provided.

A manufacturing method using the manufacturing apparatus configured as described above will be described with reference to FIGS. First, as shown in FIG. 2, the lower punch 1b is lowered by a predetermined stroke to form a concave space P in the upper portion of the through hole H of the die 1a, while the center core 3 and the side cores 4, ... The upper surface of the die 1a (the upper surface of the recess space P)
The raw material powder G is filled so that the feeder box 17 faces the concave space P at the same height.

That is, this feeder box 17
Is made slidable along the upper surface of the die 1a, for example, and the raw material powder G is stored inside. When the feeder box 15 slides on the recessed space P, the internal raw material powder G is Is dropped into the recessed space P to be filled. Then, when the raw material powder G is filled in the concave space P, the feeder box 17 retracts in a scraped state, and the raw material powder G is filled up to the upper surface of the concave space P.

Next, the piston 8 rises in the lifting cylinder 6 shown in FIG. 1, and as shown in FIG.
Rises. At this time, the raw material powder G deposited on the inclined surface t of the core chip 3a slides down along the inclined surface t, and the density of the raw material powder G increases as it approaches the center core 3.

In this state, as shown in FIG. 4, the upper punch 2
Descends. Then, the center core 3 and the side cores 4,
The upper end of each of the ... enters into each of the escape holes 15, 16, ..., and the portion excluding the center core 3 and the side cores 4, ... is strongly vertically compressed by the lower punch 1b and the upper punch 2, and the gear material W is compacted. Molded. At this time, the center core 3
The peripheral portion is formed with a high density of the raw material powder G.

Next, after the piston 8 is lowered and the center core 3 is lowered by a predetermined stroke as shown in FIG. 5, the lower punch 1b is raised to the height position of the upper surface of the die 1a, and the gear material W is discharged. Then, the discharged gear material W has high strength because the peripheral portion of the center hole c has a high density. Then, the gear material W is sintered in the subsequent process to be a product.

It should be noted that the core chip 3a having an optimum inclined surface t is replaced by the core powder 3a depending on the type of the raw material powder G, the particle size, etc., so that the powder is surely slid off.

[0022]

As described above, according to the present invention, in claim 1, the vertical hole-forming core is vertically movable within the recessed space,
Since the upper peripheral edge of the core is inclined downward, the peripheral raw material powder is not taken away by the peripheral edge of the upper surface of the core when the core is raised, and the strength is not reduced due to the decrease in density of the core. . Further, in claim 2, since the portion including at least the inclined surface of the upper end portion of the core can be replaced,
It is more convenient because the tilt angle can be adjusted to the optimum according to the type of raw material powder and particle size.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a pressed state of an upper punch and an extruded state of a lower die.

[Fig. 2] Fig. 2 is a process flow chart showing the process of compacting, and is a state diagram of filling raw material powder.

FIG. 3 is a diagram showing a state where the center core is raised in a process diagram showing a process of compacting

FIG. 4 is a powder compaction state diagram with a process diagram showing a powder compaction process.

[Fig. 5] Fig. 5 is a drawing showing a state of dispensing in a process diagram showing a process of compacting.

FIG. 6 is an explanatory diagram of a gear material that is an example of a powder compact.

FIG. 7 is an enlarged cross-sectional view of the upper end of the center core.

FIG. 8 is a state diagram showing a conventional defect

[Explanation of symbols]

1 ... Lower mold, 1a ... Die, 2 ... Upper punch, 3 ... Center core, 3a ... Core chip, c ... Center hole, G ... Raw material powder, P ... Recess space, t ... Sloping surface, W ... Gear material.

Claims (3)

[Claims] 1. A raw die powder is filled with a core for forming a vertical hole in a recessed space of a lower die, and a predetermined portion other than the core portion is pressed by an upper punch to form a perforated pressure. A manufacturing apparatus for a powder compact, characterized in that the core is vertically movable, and an upper peripheral edge portion of the core is an inclined surface which is inclined downward toward the outside. 2. The compacted compact manufacturing apparatus according to claim 1, wherein the upper end portion of the core including at least the inclined surface is replaceable. Manufacturing equipment. 3. The apparatus for producing a powder compact according to claim 1 or 2, wherein the powder compact is a gear material, and the core is provided for drilling a center hole of the gear material. An apparatus for producing a powder compact, which is characterized in that