JPH0240439B2 - FUNMATSUSEIKEISOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in powder compacting equipment used primarily in the field of powder metallurgy.

One of the advantages of powder metallurgy is, for example, gears with bosses,
It is possible to manufacture mechanical parts such as flanged bearings that have a step in the longitudinal section without using cutting.

However, in the case of conventional powder molding equipment, regardless of the case where the part is shaped so that it can stand on its own even on the protruding part (for example, the center of gravity of the part is projected into the protruding part), In the case of a part having such a shape that it cannot stand on its own due to its protruding parts, there is a problem in the process of extracting the compacted powder from the mold.

The problem will be explained below with reference to FIG.
This figure shows an example of a conventional device using the with-low method for molding a part having the shape shown in Figure 1. A shows the powder filling state, B shows the powder compressed state,
C represents the state in which the green compact has come out of the mold. Fixed lower punch 2 for forming protrusions on powder compacts
A base plate 6 equipped with a wedge 10 that slides left and right is fixed to the surface plate of the press, and a die plate 7 that holds the die 1 is attached to a yoke plate by a rod 8 that penetrates the base plate 6 and can slide up and down. 9 to form an integrated frame,
This frame 7-8-9 is raised and lowered by a lower ram of the press. On the other hand, the upper punch 4 is moved up and down by the upper ram of the press. The function of the wedge 10 is to support the floating punch 3 and receive the pressing force when compressing the powder, and also to provide a predetermined level difference to the punches 2 and 3, and to slide off in the lateral direction by the cam 11 when extracting the powder compact. This allows the floating punch 3 to descend. In addition, Core Rod 5 is the first
This is for forming the shaft hole, which is not shown in the figure, but whether or not it is necessary depends on the shape of the product.

Now, Fig. 2C shows the moment when the protrusion of the powder compact slips out of the mold hole of the floating punch 3.
It is inevitable that the powder will fall to the right at the next moment, which will often damage the edges of the powder compact or cause internal cracks. Furthermore, in the state just before this drawing, the protrusion of the powder compact slightly fits into the mold hole of the floating punch 3 and supports the main body part floating in the air, so that it is in a so-called cantilevered state. As a result, distortion occurs in the protruding portion due to eccentric load, and in severe cases, it may lead to breakage. As described above, the drawback of the conventional apparatus is that the powder compact is extracted from the mold while being supported at one point at an eccentric position.

Therefore, this invention operates in exactly the same way as the conventional device from the time of powder filling to the end of compression, and
In the process of extracting the powder compact, a support pin 12 is provided through the floating punch 3 to maintain its balance.
As the principle is shown in FIG. 3, the powder compact is extracted while being supported at at least two points by the support pins 12, thereby solving the problems of the conventional apparatus.

The present invention will be described below with reference to an embodiment shown in FIG. This figure shows a device for molding the same parts as in Figure 2 (see Figure 1). As in Figure 2, A shows the powder filling state, B shows the compressed powder state, and C shows the compressed powder state. This represents the state in which the body has come out of the mold. As is clear from the comparison with FIG. 2, this invention essentially consists of the support pin 12.
The only difference from the conventional device is the addition of .

First, in the powder filling state A, the floating punch 3 and the support pin 12 each have a spring 13
is pushed up to a predetermined height by the die 1,
Together with the fixed punch 2, a cavity 3 is formed.

From this powder filling time to the compression molding time,
The upper end surfaces of the floating punch 3 and the support pin 12 must match, and therefore the upper and lower limits of the support pin 12 are set by the nuts 14 and 15, respectively.
can be arbitrarily set using the illustrated stroke regulating device.

Next, at the end of compression molding, the green compact is supported by the fixed punch 2, the support pin 12 stopped at the lower limit, and the floating punch 3.
From this state, when the upper punch 4 is raised and then the lower ram of the press is lowered, the die 1 and then the floating punch 3 are lowered to complete the extraction in the state shown in Figure 3C.

During this time, the powder compact is supported by its own protrusions and the support pins 12 in the same posture as when it was molded, so it does not suffer damage due to falling or distortion as in the prior art.

Therefore, application of the present invention greatly contributes to improving workability and molding yield.
Note that the position, shape, number, etc. of the support pins 12 are not limited to those in the above embodiments, and may be appropriately designed in accordance with the shape of the molded product.

[Brief explanation of drawings]

Fig. 1 is a drawing illustrating the shape of a molded article to which the present invention is applied, Fig. 2 is a drawing illustrating a conventional powder molding device, Fig. 3 is a drawing illustrating the principle of this invention, and Fig. 4 is a drawing illustrating the shape of a molded product to which the present invention is applied. 1 is a diagram illustrating an embodiment of the present invention. 1...Die, 2...Fixed punch, 3...Floating punch, 4...Top punch, 12...Support pin, 13
...Spring (pushing device), 14, 15...
...Nut (stroke regulating device).

Claims (1)

[Claims] 1 In an apparatus for compression molding powder filled in a cavity formed by a lower punch consisting of a fixed punch 2 and a floating punch 3 and a die 1 between the upper and lower punches, a support pin 12 is provided passing through the floating punch 3, and , a powder molding apparatus comprising a device 13 for pushing up the support pin, and devices 14 and 15 for regulating the upper and lower limits of the support pin.