JPS6226417Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a powder compacting device mainly used in the field of powder metallurgy, and provides a powder compacting mold in which an auxiliary powder feeding mechanism is built into the upper punch.

Figure 1 schematically illustrates a mechanical part having a boss protruding on one side. When making this using powder metallurgy, it is often necessary to mold the part with the boss 1a facing the upper punch. be.

In such a case, generally, as shown in FIG. 2, the lower punch 4 is divided into a main body 4a and a boss portion 4b, each of which is set to a predetermined filling depth.
After cutting and filling the powder into the cavity formed by the die 2 and the core rod 5, the upper punch 3 having a recess corresponding to the boss of the powder compact is lowered and fitted (Fig. 3), and at the same time, the lower punch 4b is inserted. Normally, molding is performed while raising the powder and pushing the powder above it into the recess of the upper punch.

However, this molding method is originally suitable for molding green compacts in which the boss is on the lower side, and there are some problems in using it as described above.
In other words, there is a risk of cracks due to contradictory powder flows occurring in the compression process, the fact that the recesses are not always filled with powder completely, and the lower punch, which should normally be a single unit, is divided and operated individually. This is because the mold and press mechanism become complicated.

Most of these problems can be solved by filling the main body of the powder compact by scraping and filling it as usual, and by replenishing the boss part with powder from a powder supply chamber provided inside the upper punch. However, controlling the opening and closing of the powder feeding chamber and the timing thereof from the outside is undesirable because the mechanism becomes complicated.

Therefore, in this invention, the upper punch originally has a fitting hole with the core rod and a powder discharge hole from the powder feeding chamber, and the valve that opens and closes the discharge hole is operated by being pushed by the core rod. This solves all of the above problems with a simple mechanism.

Hereinafter, this invention will be explained in detail with respect to one embodiment thereof.

FIG. 4 is a longitudinal cross-sectional view of the powder molding die according to this invention, and the hole 7 visible at the center of the upper punch 3 is a fitting hole for the core rod 5, as in the conventional case (see FIG. 3). . Reference numeral 6 denotes a powder storage chamber provided above the hole 7, and therefore, the hole 7 also serves as a discharge hole for powder from the powder storage chamber. Note that 9 is a powder feeding path to the chamber 6, and 10 is an air vent hole.

Numeral 8 is a cylindrical valve that moves up and down to open and close the hole 7. Its upper and lower parts are made large in diameter so as to fit smoothly into the hole 7, similar to the core rod, and the middle part is made thinner. And this valve has a spring 11
It is always pushed downward by the
The upper large diameter portion closes the hole 7.

Now, if you lower the upper punch from the state shown in the figure,
At the same time as the upper punch fits into the die 2, the lower end of the valve 8 comes into contact with the upper end of the core rod 5, and the valve stops at that position.

As the upper punch further descends (see Fig. 5), the valve 8 is pushed up relatively, opening the discharge hole 7, and the powder in the powder storage chamber 6 flows upward as shown by arrow C in the figure. Fill the recess of the punch 3.

The upper punch continues to descend during this time, and this time the lower large diameter part of the valve 8 fits into the discharge hole 7 and closes it.
Then (see FIG. 6), the compression is completed with the core rod 5 fitted into the hole 7, and a green compact having a desired shape is formed. The subsequent extraction of the green compact is the same as the conventional method.

According to this invention, the recess provided in the upper punch can be filled with powder easily, there is no need to operate the lower punch separately, and there is no need for an external mechanism to operate the valve 8. It is possible to obtain beneficial effects even with simple modifications, such as making the text more concise.

[Brief explanation of the drawing]

Fig. 1 is a drawing illustrating the shape of a mechanical part that is the object of this invention, Figs. 2 and 3 are drawings explaining a conventional method for molding this part, and Fig. 4 is a diagram of a device according to this invention. Drawings explaining the main components,
FIGS. 5 and 6 are drawings showing the powder filling state and compression molding state of this apparatus, respectively. 1...Powder compact, 2...Die, 3...Upper punch,
4... Lower punch, 5... Core rod, 6... Powder storage chamber, 7... Discharge hole, 8... Valve, 9... Powder feeding path.

Claims (1)

[Scope of utility model registration request] It is equipped with a die 2, an upper punch 3, a lower punch 4, and a core rod 5, and the powder in the cavity formed by the die, lower punch, and core rod is compressed between the upper and lower punches to produce a compacted powder with a boss on the upper punch side. In the mold for forming the body, a storage chamber 6 is provided in the upper punch, and the fitting hole 7 with the core rod also serves as a discharge hole, and a valve 8 for opening and closing the discharge hole 7 is activated by contact with the core rod. A powder molding mold with a built-in powder feeding mechanism, characterized in that the valve is shaped like a pestle and its upper and lower large diameter parts are made to have a thickness that fits smoothly into the discharge hole 7. .