JPH0356837B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for preventing floating of a die plate in a powder molding press, particularly in a with-lower type powder molding press.

When molding with a powder molding press, it is necessary to prevent cracks from occurring in the molded product when extruding the molded product from the die (knocking out) after completion of pressurization. In other words, when knocking out a powder molded product, the upper punch begins to rise and then the die is pulled down. During this process, if the die plate that supports the die rises, the die and molded product will be separated. For example, in flanged workpieces, the die floats up, causing bending of the flange and cracking of the workpiece, especially for molded products with complex shapes. In this case, it cannot be taken out from the die, resulting in the same result that it cannot be molded. In addition, even for a relatively simple molded product, such as a cap, if the powder material is ceramic, even a slight lift of the die will cause cracks in the molded product, and the cracks will appear after the next sintering process, resulting in a defective product. It was possible that something would happen.

Therefore, in order to solve the above-mentioned problems, many conventional powder molding presses are provided with an anti-floating device. However, in the case of conventional floating prevention devices, for example, a wedge body slidably provided on the frame of a powder molding press is brought into pressure contact with a pull-down plate, and the lift-up of the die is prevented by pressing the pull-down plate downward. Alternatively, a one-way clutch fixed to the frame of the powder molding press was used to prevent the die from floating; however, with such a configuration, the lifting force of the pull-down plate, which is subjected to a large pressure force, is proportional to the pressure force. Not only is there a lack of certainty in suppressing the defects, but also a special device is required to eliminate such defects, resulting in problems such as increased manufacturing costs. In other conventional examples, the floating of the pull-down plate was regulated by operating a pneumatic cylinder, thereby preventing the die plate from floating as the upper punch rose; However, due to the lack of output, there was a lack of certainty in preventing floating, and other problems such as poor cylinder response occurred.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to utilize existing components without having to provide a special device for preventing floating. By the way,
To simply and reliably prevent floating of a die plate.

The gist of the present invention having the above object is to pressurize powder from above and below by fixing the lower punch and lowering the upper punch and tie plate.
The upper punch is fixed to an upper ram which is operatively connected to the main shaft, the lower punch is fixed to a fixed plate, and the die plate has two parts integrally connected to a vertically movable pull-down plate arranged below the fixed plate. A push-type with-lower type powder molding press includes a lifting prevention cam provided on the main shaft, and a push-down pin placed directly below the lifting prevention cam and held in a bracket provided on the upper ram so as to be able to rise and fall freely. , a nut fixed to a midway portion of the push-down pin and capable of engaging with the lower end surface of the bracket of the upper ram, the push-down pin having its upper end attached to the floating prevention cam and its lower end pulled down to the lower end. When pressurized, the bracket of the upper ram is engaged with a nut provided on the push-down pin, the push-down pin is lowered through the nut, and its lower end is brought into contact with the pull-down plate. At the same time, by lowering the die plate via the push-down pin and the pull-down plate in conjunction with the lowering of the upper ram, the powder is pushed in both directions.On the other hand, when pressing is finished, the lower end of the push-down pin is pulled down. While it is in contact with the plate, the anti-lifting cam is brought into contact with the upper end of the push-down pin, and the anti-lift cam, the push-down pin, and the pull-down plate are
It is characterized in that floating of the die plate is restricted.

Below, the present invention will be explained based on the illustrated embodiments. First, the powder molding press according to the present invention generally consists of a die set A and a die set drive mechanism B. In the figure, a die set A is replaceably placed on a bed 1 of a powder molding press, and the die set A is constructed as follows. That is, a fixed plate 2 is placed on the bed 1 of the powder molding press, and a lower punch 3 is erected on the fixed plate 2. A die plate 5 in which a die 4 is housed in the center is arranged above the fixed plate 2, while the fixed plate 2
A pull-down plate 7 with a core rod 6 erected in the center is arranged below the die plate 5 and the pull-down plate 6 are interconnected by rods 8 loosely inserted into the four corners of the fixed plate 2. It can be moved up and down as a whole. Here, the core rod 6 extends through the fixed plate 2 and the lower punch 3, and its tip is fitted into the center of the die 4 so as to be movable up and down. Further, above the die plate 5, an upper punch holder 10 having an upper punch 9 coaxial with the die 4 is vertically movable by loosely inserting a rod 11 into the left and right holes of the die plate 5. The die set A is thus constructed.

Next, the drive mechanism B of the die set will be described in detail. An eccentric cam 15 is mounted at the center of a main shaft 14 that is rotatably supported by left and right bearings 13 hanging from a frame 12 of a powder molding press. On the other hand, a cam follower 18 is connected by a pin 18 to the upper part of the upper ram 17 which integrally holds the upper punch holder 10 of the die set A via the vertical shaft 16, and the eccentric cam 1
5 and the cam follower 19 are brought into contact with each other. On the other hand, a lower ram 20 is attached to the lowering plate 7 of the die set A, which performs the above-described lowering operation of the die plate 5 at the lower part of the powder molding press. A threaded portion 21 is provided on the outer peripheral surface of the lower ram 20, and a filling adjustment nut 22 is attached to this threaded portion 21.
are screwed together. Further, at the lower end of the lower ram 20, there is a piston rod 25 of a filling cylinder 24 disposed on the base 23 of the powder compacting press.
are connected concentrically.

Next, the floating prevention device according to the present invention will be explained. A cam body 28 consisting of a floating prevention cam 26 and a knock pin cam 27 is disposed outside the main shaft 14.
is mounted, and a push-down pin 29 and a knock pin 30 are arranged in parallel at a position directly below the cam body 28. The push-down pin 29 is held by the bed 1 and the bracket 31 of the upper ram 17 so that it can move up and down, and the other knock pin 30 is held by the bed 1 and the bracket 32 of the powder molding press so that it can go up and down. There is. Cam followers 35 and 36 are pivotally attached to the upper ends of the push-down pin 29 and the knock pin 30 via pins 33 and 34, and each cam follower 35 and 36 abuts against the floating prevention cam 26 and the knock pin cam 27 on the main shaft 14, respectively. be brought into contact with Reference numeral 37 denotes a nut screwed onto the push-down pin 29. By engaging the bracket 31 of the upper ram 17 with this nut 37, the push-down pin 29 is moved downward as the upper ram 17 descends. It is what causes it to descend. Of course, the force for lowering the push-down pin 29 is also applied by the floating prevention cam 26 on the main shaft 14. 38 is a base plate arranged below the push-down pin 29 and the knock pin 30, and this base plate 38 is integrally connected to the lower ram 20;
On this base plate 38 is the push-down pin 2.
A receiving pin 39 which is brought into contact with 9 is screwed. A worm 40 is provided on the base plate 38 and is used to arbitrarily adjust the height position of the receiving pin 39. Note that the distance between the push-down pin 29 and the receiving pin 39 is set to be somewhat larger than the distance between the upper punch 9 and the die 4.

The floating prevention device of the present invention is formed by the above structure.The shape of the floating prevention cam 26 provided on the main shaft 14 is described in detail as shown in FIG. The outer peripheral shape of the cam 26 has a first cam surface 2 that forcibly lowers the push-down pin 29 in a phase delayed by the lowering of the upper ram 17.
6a, a second cam surface that continues to press the push-down pin 29 downward until the molded product is knocked out even if the upper ram 17 starts rising after reaching the lowest point; and a push-down pin that is formed after the molded product is knocked out; 2
It consists of a third cam surface 26c that releases the pressing force against 9. Therefore, in the floating prevention device of the present invention, when the upper ram 17 starts descending, its bracket 31 engages with the nut 37 of the push-down pin 29, thereby causing the upper ram 17 and the push-down pin to 29 (see Figures 2 and 3). Next, when the upper punch 9 held by the upper ram 17 starts applying pressure, the first cam surface 26a of the anti-floating cam 26 lowers the push-down pin 29 via the cam follower 35, and the push-down pin 2
The lower end of 9 comes into contact with a receiving pin 39 (see FIG. 3). After the pressurization by the upper punch 9 is completed, the upper ram 1
7 starts to rise, the anti-lifting cam 26 presses the push-down pin 29 downward with the second cam surface 26b, so the push-down pin 29 pushes against the lower ram 20 via the base plate 38. At the same time, it is possible to completely prevent the lifting of the pull-down plate 7 connected to the lower ram 20 and the die plate 5 operably connected to the pull-down plate 7 (see Fig. 4). . As shown in FIG. 5, the second cam surface 26b of the anti-lift cam 26 prevents the die plate 5 from floating even when the pull-down plate 7 is lowered one step further in order to knock out the molded product. After the knockout is completed, the third cam surface 2 of the floating prevention cam 26
6c releases the pressing force against the push-down pin 29 and returns to the original position (see FIGS. 1 and 2).

In FIG. 2, C indicates a knock-out mechanism. To briefly explain this knock-out mechanism C, a swing lever 41 is attached to a base plate 38 fixed to the lower ram 20. 41 is always biased counterclockwise by a pressing pin 42 that comes into elastic contact with one end of the lever. Reference numeral 43 denotes a projection protruding from the center lower part of the swing lever 41, which comes into contact with the stopper 44 to limit the descent of the die plate 5 when pressurizing the molded product. In addition, 45 is a stopper 44
This is a worm for adjusting the height position. When knocking out the molded product after completion of pressurization, the knock pin 30 descends and contacts the release pin 46 on the base plate 38 and presses it downward, causing the release pin 46 to close to the lever free end of the swing lever 41. is swung clockwise against the pressing pin 42, and the protrusion 43 of the oscillating lever is moved to the stopper 44.
Then, the die plate 5 and the pull-down plate 7 are lowered one step further by the filling cylinder 24, and the knockout of the molded product is completed (see FIG. 5).

The present invention consists of the above configuration and operation,
The die plate, which is operatively connected to the pull-down plate, is prevented from floating by an anti-lifting cam provided on the main shaft of the powder molding press and a push-down pin that contacts the anti-lift cam. Both the cam body and the push-down pin are those used in existing powder molding presses, so in the present invention, the bracket of the upper ram and the push-down pin in the middle are used for the initial descent of the push-down pin. It is only necessary to form an engaging portion consisting of a nut fixed to the site, and therefore, there is no need for special mechanisms or parts required for conventional anti-floating devices, which helps to reduce costs. In addition, by utilizing the strong pressing force of the anti-lifting cam installed on the main shaft, not only can the slight lifting of the die plate be completely prevented, but the phase between the upper ram and push-down pin is always constant. Since the die plate has good responsiveness and there is no timing lag in preventing the die plate from floating, it has various effects such as being able to prevent floating more reliably than in the past.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a longitudinal sectional front view of main parts showing the upper configuration of the powder molding press according to the present invention, and FIG. 2 is the lower configuration of the powder molding press shown in FIG. 1. Fig. 3 is a longitudinal sectional front view of the main part showing the process of completing the pressurization of the molded product by the same powder molding press, and Fig. 4 shows the state in which the die plate is prevented from floating when the upper punch is raised. Fig. 5 is a longitudinal sectional front view of the main part showing the completion process of extrusion (knockout) of the molded product;
The figure is an operational diagram of the upper punch, anti-float cam, and die. Explanation of symbols, 1...Bed, 2...Fixing plate, 3...Lower punch, 4...Die, 5...Die plate, 6...Core rod, 7...Drawing plate, 8, 11...Rod, 9...Top punch, 10
...Upper punch holder, 12...Frame body, 13...
Bearing, 14...Main shaft, 15...Eccentric cam, 16
... Vertical axis, 17 ... Upper ram, 18, 33, 34 ...
...Pin, 19, 35, 36...Cam follower,
20...Lower ram, 21...Threaded portion, 22...Filling adjustment nut, 23...Base, 24...Filling cylinder, 25...Piston rod, 26...Floating prevention cam, 26a...First cam Face, 26b...
Second cam surface, 26c... Third cam surface, 27... Knot pink cam, 28... Cam body, 29... Knock pin, 30... Knock pin, 31... Bracket, 32... Bracket, 37... Nut , 38
...Base plate, 39...Receiver pin, 40...
...Worm, A...Die set, B...Die set drive mechanism.

Claims (1)

[Claims] 1. Powder is pressurized from above and below by fixing the lower punch and lowering the upper punch and die plate. The upper punch is fixed to an upper ram that is operatively connected to the main shaft, and the lower punch is In a double push type with-lower type powder forming press, the die plate is fixed to a fixed plate, and the die plate is integrally connected to a vertically movable pull-down plate arranged below the fixed plate. a prevention cam; a push-down pin located directly below the floating prevention cam and held movably up and down by a bracket provided on the upper ram; and a push-down pin fixed to a midway portion of the push-down pin and attached to a lower end surface of the bracket of the upper ram. and a nut that can be engaged with the upper ram, and the lower end of the push-down pin is capable of abutting its upper end against the floating prevention cam and its lower end against the lowering plate, and when pressurized, the push-down pin is able to touch the bracket of the upper ram. The lowering pin is engaged with a nut provided on the lowering pin, and the lowering pin is lowered through the nut so that its lower end comes into contact with the lowering plate, and the die plate is lowered to the upper ram via the lowering pin and the lowering plate. By lowering the powder in conjunction with the lowering, the powder is pushed in both directions. On the other hand, at the end of pressurization, the anti-floating cam is placed on the upper end of the push-down pin with the lower end of the push-down pin in contact with the pull-down plate. A floating prevention device for a powder molding press, characterized in that the die plate is brought into contact with the die plate, and the floating of the die plate is restricted via a floating prevention cam, a push-down pin, and a pull-down plate.