JPS5852254Y2 - Powder filling equipment in metal or ceramic powder compacting machines - Google Patents

Description

[Detailed description of the invention] The present invention provides a powder molding machine in which metal powder or ceramic powder is fed into a cavity using a feeder shoe, and the powder is compression-molded within the cavity using a punch to obtain a molded product. In particular, the present invention relates to a powder filling device that can fill a cavity with metal powder or ceramic powder at a uniform density.

Conventionally, metal powder or ceramic powder is supplied into a cavity, compression molded, and then fired by powder metallurgy to produce a product.

However, when the above-mentioned ceramic powder or metal powder is filled into the cavity, friction occurs between the powders or between the powder and the cavity, so it has not been possible to fill the cavity with uniform density.

Therefore, there is a method of adding zinc stearate or the like to the powder as a powder lubricant to increase the fluidity of the powder and filling it into the cavity, but it has not been possible to fill each part of the cavity with a uniform density.

In recent years, there has been an increase in the number of automobile industry parts that use ceramic powder or metal powder (hereinafter simply referred to as powder). Different parts of the molded product sometimes caused problems with the product.

For example, clutch hubs, which are automobile parts, are products that require dimensional accuracy. Conventionally, metal powder is used to fill the cavity of a molding die, and then the metal powder is compression-molded within the cavity using a punch. A molded product is obtained, which is then sintered.

That is, as shown in FIG. 1, the conventional metal powder filling apparatus connects a powder supply hopper (not shown) and a feeder shoe 1 for transferring powder through a conduit 2, and connects the feeder shoe 1 with a connecting rod 3. A mold 7 is provided at a position where the feeder shoe 1 moves and feeds the powder, and a certain amount of metal powder is fed into the cavity 6 of the mold 7. It is configured so that it is supplied to the inside.

Therefore, when using this device, when the feeder shoe 1 retreats, the amount of powder in the hopper is the sum of the amount of powder filled into the cavity 6 and the amount of excess powder that should remain in the feeder shoe 1 from the conduit 2. The feeder shoe 1 is filled by dropping.

The powder filled in the feeder shoe 1 is caused to fall into the cavity 6 when the feeder shoe 1 moves forward over the cavity via the rerod 3 due to the pressure of the hydraulic drive device, and the powder is caused to fall into the cavity 6. Start filling from the right end and gradually fill towards the left end.

Next, the feeder shoe 1 is passed through the rod 3 to the mold 7.
When retracting over the feeder shoe, the desired metal powder is filled into the cavity 6 by scraping at the lower edge of the feeder shoe.

After that, the cavity 6 is punched with punches 8a and 8b.
A powder molded product is obtained by compression molding the metal powder inside.

The molded article is separately fired to become a product.

However, in the conventional metal powder filling device, the forward end of the feeder shoe 1, which is slid in the front-rear direction (left-right direction in FIG. 1) via the connecting rod 3, Since the position is designed to coincide with the center Fb of the cavity 6 of the mold 7, at the forward end position of the feeder shoe 1 (the position shown in FIG. 1), the excess powder remaining in the shoe 1 will be removed from the surface as shown in the figure. is tilted downward to the left, and the packing density of the powder filled in the cavity 6 is such that at point D, which is the corner on the forward end side of the feeder shoe 1, the weight of the powder in the upper part is small. The powder density at the feed point position is smaller than the powder density near the center Fb or at the rear (right side) of the center Fb, for example at the point A position, and as the feeder shoe 1 retreats from its forward end, the cavity When grinding the powder on the upper surface of cavity 6, the powder has little fluidity, so even though the density of the powder inside cavity 6 is uniform in other parts, the density near point D is smaller than in other parts. There were drawbacks.

Therefore, when the powder in the cavity is compression-molded by the punches 8a and 8b after the feeder shoe 1 has retreated, the D of the molded product is
There were disadvantages in that eccentricity occurred near the point position, and the molded product warped or distorted after firing.

In order to counter this, the above-mentioned drawbacks have been taken, such as by vibrating the feeder shoe so that it falls down due to gravity, or by increasing the amount of powder remaining in the feeder shoe to increase the weight of excess powder remaining in the feeder shoe. However, in the former case, the vibration causes separation of the powder, and in the latter case, the height of the feeder shoe cannot be increased due to the operation of the press machine, so this problem still cannot be solved satisfactorily.

Therefore, the present invention eliminates the above-mentioned drawbacks, and at the same time, it is possible to fill the cavity with a constant amount of powder at all times, and with a small amount of excess powder, it is possible to fill each part of the cavity with powder at an even density. It is an object of the present invention to provide a filling device, and furthermore, to obtain a filling device that can demonstrate a filling effect without powder filling defects when baking the filled compact according to the present invention to obtain a product.

That is, the powder filling device of the powder molding machine of the present invention includes a molding die provided in a part of the base, an upper punch and a lower punch movably provided in the cavity of the molding die, and the base. A molding machine comprising a powder filling device having a feeder shoe which is slidably disposed on the powder and is to be fed to a ceramic or metal mold to be molded, the feeder shoe having a rectangular frame shape and connected to the feeder shoe. The center of the feeder shoe extends beyond the center of the cavity of the molding die by a length of 1/3L to 5/6L (where L is the inner diameter along the direction of movement of the feeder shoe), so that the forward position is the forward end. The feeder shoe used in the present invention is characterized by having a hydraulic drive device that reciprocates the cavity shape, regardless of whether the cavity shape is circular, angular, or irregularly shaped. A rectangular frame may be prepared.

In addition, when carrying out the present invention, the amount of powder filled into the feeder shoe is determined by the fact that the cavity of the molding die is rectangular
When using a feeder shoe with the same shape as this, the feeder shoe has a cavity volume of about 1.5 to 3 times the cavity volume.
It is desirable to introduce twice the amount of powder, and in the case of the illustrated embodiment, it is desirable to make the volume of the inner cavity of the feeder shoe the same magnification. In view of the purpose of supplying the liquid evenly and sufficiently within the interior of the interior, the amount can be appropriately selected within the range of 1/3L to 5/6L.

That is, if the powder is moved below 1/3L, the inner cavity of the cavity on the forward end side of the feeder shoe will not be sufficiently filled with powder, and if the powder is moved beyond 5/6L, the filling density of the powder into the cavity will not be improved. On the other hand, this is disadvantageous because the stroke of movement of the feeder shoe becomes longer.

Hereinafter, the present invention will be explained in detail with reference to examples.

FIG. 2 is a sectional view showing an embodiment of a powder filling device in a powder compacting machine according to the present invention.

That is, the apparatus of this embodiment includes a pipe 11 for feeding powder from a powder supply source (not shown), and a base 14.
a hopper 12 fixed to the hopper, a sliding plate 13 that is in sliding contact with the lower edge of the hopper and can freely slide on the base 14, and a sliding plate 13 that is slidable with its lower edge in sliding contact with the upper surface of the base 14. , and a rectangular frame-shaped feeder shoe 17 provided integrally with the sliding plate 13, the molding die 1 is arranged on a part of the base 14.
The powder is supplied and filled into the cavity 16 of No. 5.

The feeder shoe 17 is connected to a hydraulic drive device (not shown) via a guide rod 18, and has a sliding plate 13 whose lower surface is supported and guided by a guide roller 20 provided on the base 14.
At the same time, it slides in the horizontal direction in the plane of the paper by a hydraulic drive device, receives powder from the hopper 12 at its retreat position, and supplies powder in the shoe 17 into the cavity 16 of the molding die 15 at its forward position. Fill.

Furthermore, the center G of the feeder shoe 17 is located on the base 14 so that the center G of the feeder shoe 17 extends 1/
A rotary limit switch 19 is provided, which is activated to cut off the driving force of the hydraulic drive device when it reaches a position where it has advanced to a length of 3 to 5/6 L, and corresponds to the cam 23 on the lower surface of the sliding plate 13. ing.

Further, the guide roller 20 serves to keep the lower surface of the feeder shoe 17 in close contact with the upper surface of the cavity 15 at all times.

Note that 24 indicates the feeder shoe 17 when the feeder shoe 17 is retracted.
This is a cam that comes into contact with a limit switch 19 for stopping the hopper 7 at the lower end opening of the hopper 12.

To fill the cavity with the above-described device, first, a desired amount of powder is filled into the feeder shoe 17 from the lower end opening of the hopper 12.

Next, the feeder shoe 17 is moved forward by a prescribed stroke on the base 14 via the guide rod 18 by the driving force of the hydraulic drive device.

At this time, the lower end opening of the hopper 12 is closed by the upper surface of the sliding plate 13.

As the feeder shoe 17 advances, the powder in the feeder shoe 17 is gradually supplied to the cavity 16 of the mold 15 provided on the base 14, and uniformly supplied into the cavity 16 at the forward end of the feeder shoe.

Further, when the feeder shoe 17 is moved backward on the base 14 by the driving force of the hydraulic drive device, the lower edge of the feeder shoe is used to scrape and fill the feeder.

At the same time, a certain amount of excess powder is left on the feeder shoe 17, which returns it to its initial position on the base.

On the other hand, the powder filled into the cavity 16 by slicing is pressed into the cavity 16 by an upper punch 21 and a lower punch 22 movably provided with respect to the mold 15, and then pushed up by the lower punch 22. and is ejected from the mold.

According to this device, the inner diameter of the feeder shoe 17 is configured in the shape of a rectangular frame that is circumscribed by or slightly larger than the outer shape of the cavity 16 of the molding die 15, and the frontmost frame side of the shoe 17 in the front-rear direction is The feeder shoe 17 is mounted almost at right angles to the moving direction of the shoe, and the center G of the feeder shoe 17 is 1/3L to 5/6 beyond the center H of the cavity 16.
The forward end is defined as the position advanced by a length of L (where L is the internal dimension in the front-rear direction of the feeder shoe) (to the left in the figure), so at the forward end of the feeder shoe 17, the frontmost frame side of the feeder shoe 17 is Inner diameter of feeder shoe 17 and cavity 1
Even if the maximum internal dimension (in the front-rear direction) of the feeder shoe 17 is the same, it is at a position that is 1/3L to 5/6L forward, and therefore the excess powder in the feeder shoe 17 is moved to the left as shown in the figure. Even if the excess powder is accumulated in the downward direction, the excess powder is quite thick at the front end of the cavity 16 (the leftmost end in the figure), and the packing density of the powder in this part does not become lower than that in other parts.

This can be confirmed by experiment as follows.

Note that in the following, the overshoot distance is referred to as
Let us assume that the distance that the center G of the feeder shoe 17 advances beyond the center H of the cavity 16 of the molding die 15 at the forward end stop position of the feeder shoe 17, that is, the distance ΔL between G and H.

Therefore, ΔL=O indicates when the torso centers G and H coincide (the conventional device).

A rectangular molded product was obtained using the apparatus of this example.

That is, from the hopper 12, the length is 25 meters, the width is 60 mm,
Gradually fill the powder into the cavity 15 with a depth of 80 mm,
At this time, as shown in FIG.
Punch load (pressure load 0.3 kg/
cm3) was measured using a load cell attached to a punch.

The results are shown in FIG. In the figure, C9△ represents the difference between the load at position C of the upper punch and the load at position F, and .mu represents the difference between the load at position C and the load at position B of the upper punch. When the cavity is filled with powder in an amount 1.5 times the volume of the cavity, the broken line represents the case where three times the volume of powder is used in the same manner as above.

The above load is proportional to the packing density of the powder.

As can be seen from the results, in any case, when the overshoot distance ΔL is 0 (conventional example), the load difference between the left and right sides is large, ranging from 20 mm to 50 mm (1/3L to 5
/6L) It was found that when moving (this invention), the load differences between C and F and between C and B become smaller.

This moves the center of the feeder shoe beyond the center of the cavity, making it particularly difficult to fill inside the cavity. The remaining excess powder exerts pressure due to the movement, and therefore, the pressure due to the movement of the feeder shoe is sufficiently applied to the corner of the cavity, and the weight of the excess powder remaining on the feeder shoe is also applied to the corner. Therefore, each part of the cavity is filled with uniform density.

As described above, in accordance with the present invention, the feeder shoe is made into a rectangular bar shape, and the center of the feeder shoe extends beyond the center of the cavity of the mold, and the length is 1/3L to 5/6L, where L is the length of the feeder shoe. Since the powder is filled into the cavity by moving the powder forward (inner dimension along the direction of movement), powder can be evenly filled into each part of the cavity that is difficult to fill.

Therefore, since there is little variation in packing density, the influence on the molded product is small.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a powder filling device in a conventional molding machine.
Figure 2 is a sectional view of the powder filling device used in the embodiment of the present invention, Figure 3 is a diagram showing the upper punch load measurement position in the embodiment of the present invention, and Figure 4 is the upper punch in the embodiment of the present invention. It is a graph showing position load of. In the figure, 12 is a hopper, 14 is a base, 15 is a mold, 1
6 is a cavity, and 17 is a feeder shoe.

Claims (1)

[Scope of Claim for Utility Model Registration] A mold provided on a part of the base, an upper punch and a lower punch movably provided in the cavity of the mold, and a mold that is slidable on the base. A molding machine comprising a powder filling device having a feeder shoe to be provided and supplied to a ceramic or metal mold to be molded, the powder filling device having a feeder shoe in the form of a rectangular frame, and a powder filling device connected to the feeder shoe and having a center portion of the feeder shoe. is 1/3L to 5/6L long beyond the center of the mold cavity, but L
1. A powder filling device for a metal or ceramic powder molding machine, characterized in that it has a hydraulic drive device for reciprocating the feeder shoe so that the forward position is the forward end (inner direction along the moving direction of the feeder shoe).