JPS6321538Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of the so-called Cincinnati type press among powder forming presses mainly used in powder metallurgy.

Traditional presses, which have been used since the early days of powder metallurgy, have a relatively simple structure with one ram at the top and one at the bottom, operated by hydraulic or mechanical power. The molds such as the lower punch and the like are attached to a die set, and this die set is attached to and removed from the press. A representative example of this type of press is the West German Dimetag press, which is a hydraulic type.

When molding powder, the die and the lower punch move up and down relative to each other, but depending on which of them is fixed to the press, the die set can be assembled with either a fixed die or a movable lower punch (see Figure 5). There are two types: fixed lower punch type and movable die type (see Fig. 6), which is generally referred to as a with-lower die set.

The former is often used for small mechanical presses, while the latter is suitable for mass producing parts with complex shapes using relatively large presses, and has become the mainstream method for forming sintered mechanical parts.

By the way, when the shape of the part is simple, that is, when there is no step at the bottom as shown in Figure 4, the structure of the die set is simple, and the lower punch is fixed to the ground plate and the die is moved by the lower ram of the press. It is sufficient to provide floating support. (The upper ram of the press moves the upper punch up and down.) However, if the shape of the part is complex, for example if there is a step at the bottom as shown in Figure 7, the structure of the die set will be complicated because the lower punch is divided. become.

Figure 8 shows the parts shown in Figure 7 (gear with boss)
This figure shows an outline of a with-roal die set for forming a part, in which the lower punch is divided into a fixed punch 11 and a floating punch 10, corresponding to the step of the part.
The stationary punch is fixed to the base of the press via the ground plate, and the floating punch is floatingly supported on the column plate by a spring.

On the other hand, the die 6 is attached to the die plate, and the core rod 12
is fixed to a column plate provided on the lower ram of the press, and the die plate and column plate are connected by a column that passes through the ground plate. Therefore, the die 6 and the core rod 12 move up and down simultaneously according to the operation of the lower ram. In the above description, the reference numerals of the die set components have been omitted, but the operation of this device, including its operation, should be easily understood from the drawings.

Now, such a die-setting method is suitable for molded products having a lower level difference of up to one level, but there are problems when the level difference is more than that. In other words, in order to form a two-step difference, it is necessary to further divide the floating punch into two.
In practice, it is extremely difficult to incorporate a mechanism for individually raising and lowering a die and two floating punches using a single lower ram into the limited space of a die set. Therefore, when molding a part with two steps using a dimetag type press, the current situation is to use a stepped die instead of dividing the floating punch. (Since the step part of the die is pressed one-sidedly, the density of the compact becomes uneven.) In contrast to the die set type press mentioned above, a press developed with a completely different concept for the purpose of multi-stage forming, There is a so-called Cincinnati Press made by the Cincinnati Company.

Broadly speaking, this press has the function of a die set built into its main body, and the plate in the die set is called a platen in this press. However, this platen is extremely thick and has a highly rigid structure compared to the die set plate.

FIG. 9 shows an outline of this Cincinnati-type powder molding press. If you compare it with Figure 8, you will notice that the die plate and die platen 3 of the die set correspond to each other, and the ground plate and base platen 2 correspond to each other, and in the case of a die set, there is only one plate that holds the floating punch. On the other hand, in this press, the platens 4 and 5 correspond to this, and it is understood that the platens 4 and 5 have one more stage, that is, the floating punch can be divided into two pieces and mounted individually.

In the figure, 3 is a die platen that holds the die 6, and a pneumatic cylinder 13 provided on the upper frame 1.
It is raised and lowered by

The platens 4 and 5 hold divided floating punches 9 and 10, respectively, and have pneumatic cylinders 14 and 10, respectively.
15, the fixed punch 11 is raised and lowered relative to the base platen 2 that holds the punch 11. Reference numerals 17 and 18 are releasable stoppers that restrict the lower limit of the platens 4 and 5 to a predetermined molding position.

In the illustrated example, since there is a step in the shaft hole of the molded body, the core rod 12 is a stepped core, and is equipped with a pneumatic cylinder 16 and a stopper 19 for raising and lowering the core, but in the case where there is no step in the shaft hole. teeth,
The core rod can remain fixed.

Each cylinder 13 to 16 is driven by detecting the rotation angle during one molding cycle with a rotary encoder 20 provided on the upper ram 7 side and switching each valve 22 via a sequencer 21. There is.

≪Problems with conventional presses≫ Now, with the trend in recent years to make various mechanical devices smaller and lighter, gears, cams, and other mechanical elements used in these devices have been changed to sintered parts, and multiple parts have been integrated into one piece. The design shapes of sintered mechanical parts are becoming more and more complex as a result of demands for multiple functions in one part.

However, with the above-mentioned Cincinnati type press, it is possible to mold a molded article with a step difference in the lower part of up to two steps, which is one more step than with a die set press, but it is not possible to mold a product with a step difference greater than that. Even if the floating punch is further divided to increase the height difference, it is not possible to incorporate an additional platen to hold it; on the other hand, the die platen 3 is simply supported by the pneumatic cylinder 13 and does not have a fixing device. Since there is no,
This is because a stepped die cannot be used either.

≪Structure of the invention≫ Therefore, as a result of various efforts made by the inventors of the present invention,
Without making any particular modifications to the existing Cincinnati-type press itself, it is possible to use a stepped die by devising a device that is installed between the upper frame and die platen to fix and release the die platen at a predetermined molding position. This solves the above problem.

The present invention will be described in detail below with reference to one embodiment thereof.

Figure 1 shows the outline of the Cincinnati type powder molding press to which the present invention is applied, and shows the fixing device 23.
The overall configuration is the same as that in FIG. 9, except that the die 6 is newly installed and the die 6 is a stepped die.

A stepped portion 6a is formed on the inner periphery of the die 6 provided on the die platen 3. Also die platen 3
is connected to the upper frame 1 via a fixing device 23.

This fixing device 23 consists of a sleeve 24 having one end fixed to the lower part of the upper frame 1, and a rod 25 having one end fixed to the upper part of the die platen 3 and reciprocating up and down within the sleeve.

A more detailed configuration of this fixing device 23 is shown in FIG. This device 23 includes a disk 26 that is rotatably supported on the outer periphery of the upper part of the rod 25 within a sleeve 24, a movable lock member 27 that is integrated with the lower part of this disk 26, and The rotary actuator 28 is provided at the top of the rod 25, and a planetary pinion 30 is fixed to the output shaft of the actuator and meshes with a fixed gear 29 provided at the top of the rod 25.

In addition, on the lower outer periphery of the movable lock member 27,
A plurality of fan-shaped engagers 27a shown in FIG. 3a are integrally provided.

Sleeve 24 facing movable lock member 27
Insert the rod 25 into the inner lower part of the
A fixed lock member 31 is provided on its upper surface with a plurality of fan-shaped engagement grooves 31a similar to the engagement member 27a.

A male thread is cut on the lower outer periphery of the locking member 31, and is screwed into a large diameter gear 32 having a female threaded portion on the inner periphery.

The large diameter gear 32 meshes with a pinion 33 inserted inside the lower part of the sleeve 24, and
This pinion 33 is connected to a worm 34 and a worm wheel 35 for adjustment.

Furthermore, as shown in FIG. 3b, a sleeve 36 for preventing rotation is provided on the outer periphery of the stationary side locking member 31.
A key 36a is inserted between the sleeve 36 and the stationary lock member 31 to prevent rotation in the radial direction. Therefore, by rotating the worm 34 in the forward and reverse directions, the stationary side locking member 31 moves in the vertical direction along the lead of the threaded portion, and the fixing position of the die platen 3 can be finely adjusted.

Next, the molding process in the press equipped with this fixing device will be described.

First, when filling the powder (the state shown on the left side of Figures 1 and 2), each platen 3 to
5 rise to a predetermined filling position, and accordingly, the rod 25 connected to the die platen 3
has also risen to the position shown.

Next, the ram 7 descends and the upper punch 8 applies pressure. Along with this, the die platen 3, second platen 4, and third platen 5 are also lowered.
The platens 4, 5 and the core rod 12 are brought into contact with the stoppers 17, 18, 19, respectively.
The lower limit is regulated to a predetermined molding position.

Further, as the die platen 3 descends, the rod 25 of the fixing device also descends, and the movable stopper member 27
The engagement element 27a stops when it comes into contact with the upper edge of the fixed side lock member 31. Therefore, the die platen 3 is fixed at a predetermined molding position in a suspended state, and it becomes possible to receive pressure and compact the powder at the stepped portion 6a of the die.

The end of this pressurizing process is detected by the rotary encoder 20, and the rotary actuator 28 is actuated in response to a command from the sequencer 21, causing the movable lock member 27 to rotate 45 degrees. Along with this rotation, the engaging piece 2 of the movable locking member 27
7a is aligned in phase with the engagement groove 31b of the stationary side locking member 31 and enters therein, thereby releasing the fixation of the rod 25 and therefore the die platen, allowing it to be lowered.

After the pressurization is completed, the upper punch is raised, the stoppers 17 to 19 are released, and the platens 3 to 5 and the core rod are lowered, thereby ejecting the molded product from the mold while riding on the fixed lower punch 11.

After that, each member is returned to the powder filling position on the left side of FIG. 1, and one molding cycle is completed.

The following two points can be cited as effects of this idea. First, with this invention, it is possible to form compacts with complex shapes that have one step more than conventional Cincinnati-type presses. This greatly contributes to improving the productivity and reducing costs of mechanical parts.

Secondly, when applying this invention, there is no need for any special modifications to existing presses, and it is sufficient to simply connect the above-mentioned fixing device to the upper frame of the press and the die platen. The practical effects of this can be highly evaluated.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a Cincinnati-type powder molding press equipped with a fixing device according to the present invention, Fig. 2 is a longitudinal sectional view of the fixing device, and Fig. 3 is a movable side lock member and a fixed side lock that constitute the fixing device. FIG. 4 is a cross-sectional view showing the contour of the member; FIG. 4 is a drawing illustrating a molded body with a simple shape; FIGS. The figure is a drawing illustrating a molded body with one step at the bottom,
FIG. 8 is a diagram showing a with-lower die set type press for molding the one shown in FIG. 7, and FIG. 9 is an explanatory view of a conventional Cincinnati type powder molding press. 1... Upper frame, 2... Base platen,
3...Die platen, 4...Second platen,
6...Die, 5...Third platen, 11...Fixed lower punch, 9, 10...Floating lower punch, 23...
...fixing device, 24...sleeve, 27...movable side lock member, 25...rod, 31...fixed side lock member.

Claims (1)

[Claims for Utility Model Registration] 1. Between the lower frame and the upper frame of the press, in order from the bottom, there is a base platen that holds a fixed lower punch, and a floating lower punch that is supported in a floating manner so that it can be raised and lowered by the drive mechanism of the press. In a press that is equipped with a platen that holds a platen and a die platen that holds a die, and compresses and molds powder in the die between upper and lower punches, the die is a stepped die,
A powder molding press characterized in that the die platen and the upper frame of the press are connected by a fixing device that fixes and releases the die platen at predetermined times during the molding cycle. 2. The fixing device includes a sleeve fixed to either the upper frame or the die platen, a rod fixed to the other one and reciprocating up and down within the sleeve as the die platen goes up and down, and a rod located inside the sleeve and attached to the outer periphery of the rod. a movable side lock member which is rotatably supported by the movable side lock member and has an engaging element integrally provided on its periphery; A utility model according to claim 1, comprising a fixed side lock member provided with an engagement groove for engaging the engaging element, and a rotation mechanism for rotating the movable side lock member by a predetermined angle. Powder forming press.