JP2552993B2 - Powder molding press - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder molding press which adjusts a gap between a lower ram and a yoke plate in order to facilitate replacement of a die set and improve accuracy of a molded product.

[0002]

2. Description of the Related Art In a powder molding press, it is necessary to replace a die set including an upper punch and a lower punch according to a molded product. As such a die set exchange device, Japanese Patent Application No. 55-163573 “Die set exchange device for powder molding press” proposed by the present applicant, Japanese Patent Application No. 55-163573.
No. 165342 “Molding press loader device” and Japanese Patent Application No. 57-131549 “Powder molding press die set replacement device” have been conventionally known. These replacement devices are used for powdering a large die set. Used to attach and detach within the body of the molding press. The small die set is manually replaced.

An example of the structure of the die set will be described with reference to FIG. The die set 1 is composed of various parts from a yoke plate 2 to an upper punch plate 3, and the yoke plate 2 is detachably attached to a lower ram 4 which is vertically movable to the lower side of the powder molding press main body A. To be A guide rod 6 penetrating the fixed plate 5 is erected on the yoke plate 2 that is attached to and detached from the lower ram 4, and the die plate 7 is provided at the upper end of the guide rod 6.
Is attached. The fixing plate 5 is fixed to the press body A by bolting or hydraulic clamping via the holder.
Is fixed at a predetermined height position. Further, on the fixed plate 5, a lower punch 9 which is inserted from below into a die 8 mounted in the central portion of the die plate 7 is attached. The upper punch plate 3 is detachably attached to a clamper 11 provided on the upper side of the powder molding press body A. The clamper 11 is attached to the lower surface of the upper ram 10 which is moved up and down by a driving device (not shown). On the lower surface of the upper punch plate 3, the die plate 7
A guide rod 12 penetrating therethrough is attached, and the guide rod 12 guides the vertical movement of the upper punch plate 3. A die 8 is provided on the lower surface of the upper punch plate 3.
An upper punch 13 that is inserted into the inside is attached. In this die set 1, the material powder is loaded in the space formed by the die 8 and the lower punch 9 that is inserted into the die 8 from below, and the material powder is pressed by the upper and lower punches 9 and 13, respectively. A molded product 14 is produced. When the die set 1 is attached to or detached from the press body A, the height position is aligned between the upper punch plate 3 and the lower ram 4 using the exchanging device as exemplified above, and the yoke plate is horizontally slid. 2 needs to be slid into the lower ram 4 smoothly. For this reason, a gap G of about 0.1 to 0.3 mm is generally provided between the yoke plate 2 and the lower ram 4.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The upper punch plate 3, the fixed plate 5 and the yoke plate 2 are fixed to the press body A at three positions. Among these, the fixing of the yoke plate 2 to the lower ram 4 has a significant influence on the accuracy of the molded product. The gap G needs to be fixed to the press body A in a state where there is no play that minimizes the gap G close to zero. As described above, it is desirable that the gap G is as large as possible in consideration of only the attachment / detachment operation of the die set 1, but in order to improve the accuracy of the molded product, it is necessary that the gap G is a minimum state close to zero when pressing. Desired conflicting requirements are required. That is, the clamper 1 of the upper punch plate 3
Since a force corresponding to the weight of the upper punch 3 is applied to 1 when the upper ram 10 rises, a hydraulic clamper or a bolt clamper having a weak force can be sufficiently used. Also, the clamper portion of the fixed plate 5 has a weak force acting in the direction of raising the fixed plate 5, and therefore can be fixed by the same method. However, a large force is applied to the yoke plate 2 from above and below during pressing, and the lower ram 4 has to contact the lower surface of the yoke plate 2 to support the load from above. The yoke plate 2 is simultaneously pulled down by the lower ram 4. For this reason, the lower ram 4 needs to be attached to the yoke plate 2 with as little play as possible. Further, since the gap G between the yoke plate 2 and the lower ram 4 has a great influence on the accuracy of the molded product 14, it is necessary to make the gap G as close to zero as possible. In FIG. 3, the force applied from the upper punch 13 to the lower ram 4 at the time of pressurization is shown by an arrow P1, and in FIG.
It shows with. When the molded product 14 becomes large, the force at the time of extraction may reach 60% of that at the time of pressurization.

More specifically, at the time of molding, the material powder does not enter the die 8 and the lower punch 9 at the beginning, so there is no friction between the die 8 and the lower punch 9, but the material powder enters and the guide rod 6 and the insertion hole. If the precision with 5a is poor, the friction becomes large. When this friction is small, when the lower ram 4 is raised to reach the prescribed position and stopped due to the filling of the material powder, the yoke plate 2, the guide rod 6 and the die plate 7 are inertial. The gap G is projected upward, and then it is lowered by its own weight so that the lower portion of the yoke plate 2 and the upper portion of the lower ram 4 come into contact with each other. Further, when the friction is large to some extent, the respective parts that are upwardly projected by the gap G due to the inertia as described above do not return by their own weight, and the filling position of the material powder becomes higher by the gap G. Further, when the friction is large, the respective parts are not projected upward by the inertia when reaching the specified position when the filling is increased, and the lower part of the yoke plate 2 and the upper part of the lower ram 4 are always in contact with each other. . When the focus position changes in this way, the filling amount of the material powder varies, and the precision of the pressed molded product is significantly reduced. For example, the filling depth is 20mm
If a variation of 0.3 mm occurs in the product, the molded product 14
The error is 0.3 / 20 × 100 = 1.5%, which is a non-negligible amount.

Therefore, the present invention has been proposed in order to solve the above-mentioned problems of the prior art. When the die set is mounted on the press body, a large gap is formed between the die set and the lower ram, We provide a powder molding press that makes it easy to insert the die set, and after the die set is inserted, the gap is adjusted to a minimum close to zero and is fixed in a play-free state to improve the precision of the molded product. To aim.

[0007]

In order to achieve this object, a powder molding press according to the present invention is provided with an upper part in a lower ram into which a yoke plate of a die set is inserted and removed when the die set is attached to and detached from a press body. A gap adjusting screw that is screwed in the vertical direction is provided, and a fluid actuator or other rotary drive means is attached to the lower part of the lower ram, and the drive shaft of this rotary drive means is adjusted by a rotary shaft that penetrates the axis of the lower ram. It consists of a structure connected to a screw.

[0008]

According to the above construction, if the gap adjusting screw is rotated by the rotation driving means and retracted into the lower ram, a sufficient gap between the yoke plate and the lower ram can be secured, and the die set. Becomes easier to insert into the press body. Also, after inserting the die set into the press body, if the gap adjusting screw is moved forward to contact the lower surface of the yoke plate, the gap can be fixed to the minimum value close to zero without any play. it can.

[0009]

EXAMPLES Specific examples of the powder molding press according to the present invention will be described in detail below with reference to the drawings. The same parts as those in the conventional example are designated by the same reference numerals, and the description of the overlapping parts will be omitted. FIG. 1 shows a vertical sectional view of this powder molding press. In this figure, the female screw portion 15 is provided on the upper portion of the lower ram 4 to which the yoke plate 2 of the die set 1 is attached and detached.
Is formed in the central portion in the vertical direction, and this female screw portion 15
The gap adjusting screw 16 is screwed into the. The lower ram 4, which is moved up and down by the driving of the hydraulic cylinder 17, is provided with an insertion hole 18 penetrating the shaft center, and the connection shaft 19 is inserted into the insertion hole 18. The shaft 19 is rotatable by metal bearings 20 and 21 fitted above and below the insertion hole 18, and an upper end portion of the shaft 19 is connected to a lower portion of the gap adjusting screw 16. An actuator mounting plate 22 is fixed to the lower end of the lower ram 4, and a hydraulically actuated rotary actuator 23 is mounted upward on the lower surface of the mounting plate 22. The lower end of the connecting shaft 19 penetrating the mounting plate 22 is connected to the drive shaft 24 of the rotary actuator 23 via a spline. A rod 26 protruding from the lower cover of the hydraulic cylinder 17 is inserted into the bush 25 fitted in the mounting plate 22 to prevent the mounting plate 22 from rotating. As a result, when the rotary actuator 23 is actuated by hydraulic pressure and the drive shaft 24 is rotated, the connecting shaft 19
The gap adjusting screw 16 is screwed up and down through the
The gap G between the yoke plate 2 and the lower ram 4 can be adjusted. Here, the gap adjusting screw 1
The position where 6 fully rotates and contacts the lower surface of the yoke plate 2 is set to be the end of the rotation range of the rotary actuator 23.

In the powder molding press constructed as described above, when the die set 1 is inserted into the press body A, the gap adjusting screw 1 is rotated by the rotary actuator 23.
2 is rotated counterclockwise to fully retract the adjusting screw 16 in the female screw portion 15 as shown in FIG.
As a result, the gap G between the yoke plate 2 and the lower ram 4 can be sufficiently secured as compared with the conventional case, and the die set 1 can be inserted into the press body A very easily. After the die set 1 is attached to the press body A, the rotary actuator 23 is operated to rotate the gap adjusting screw 16 clockwise to move it forward, and as shown in FIG. 2B, the adjusting screw 16 is moved to the yoke plate 2. Abut.
As a result, the gap G between the yoke plate 2 and the lower ram 4 is fixed in a state where there is no play, which is a minimum value close to zero, and there is no variation in the filling position as in the conventional case, so that powder molding is performed. The accuracy of the product 14 is improved. When the die set 1 is pulled out from the press body A, the gap adjusting screw 16 is fully retracted to facilitate the work with the gap G sufficiently secured.

As a means for rotating the gap adjusting screw 16, instead of using the rotary actuator 23, a driving means in which an induction motor, a DC motor, a servo motor or the like is combined with a speed reducer may be used. In this case, a positioning means for stopping at the position where the gap G becomes the minimum value is required. Further, the powder molding press of the present invention is not limited to the hydraulic press and may be a mechanical press.

[0012]

As described above, according to the present invention, the gap adjusting screw is provided in the lower ram, and the adjusting screw is rotated at the lower end position of the lower ram by the driving means such as the rotary actuator to form the yoke plate. Since the gap between the lower rams can be adjusted, this gap can be sufficiently secured when inserting the die set into the press body, and the gap is 0.1 to 0.
Unlike the case where only about 3 mm is secured, the die set can be inserted into the press body much more easily. Also, after mounting the die set on the press body, by rotating the gap adjusting screw and bringing the adjusting screw into contact with the yoke plate, the gap can be fixed to the minimum value close to zero without play. Therefore, the precision of the powder-molded molded product can be improved as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a powder molding press according to the present invention.

FIG. 2A is a longitudinal sectional view showing a state in which the gap adjusting screw is fully retracted, and FIG. 2B is a state in which the gap adjusting screw is fully advanced.

FIG. 3 is a vertical sectional view showing a conventional powder molding press.

FIG. 4 is a diagram showing a force applied to a lower ram when a molded product is pulled out.

[Explanation of symbols]

1 Die set 2 Yoke plate 3 Upper punch plate 4 Lower ram 5 Fixed plate 6 Guide rod 7 Die plate 8 Die 9 Lower punch 10 Upper ram 11 Clamper 12 Guide rod 13 Upper punch 14 Molded product 15 Female thread 16 Gap adjusting screw 17 Hydraulic pressure Cylinder 18 Insertion hole 19 Connecting shaft 20,21 Metal bearing 22 Mounting plate 23 Rotary actuator 24 Drive shaft 25 Bush

Claims (1)

(57) [Claims] 1. A powder molding press in which a die set is horizontally moved to attach and detach the die set between an upper ram and a lower ram of the press body, and a locking recess provided in a yoke plate of the die set .
Between the locking projections provided on the lower ram of the press body ,
The inner dimension of the locking recess and the outer dimension of the locking projection are set so that a sufficient gap is secured in the height direction, and a gap adjusting screw is embedded in the upper end side of the lower ram. Suitable for replacement of a die set in which the gap adjusting screw is retracted into the lower ram so that a sufficient gap is ensured between the locking recess of the yoke plate and the locking projection of the lower ram. A second set suitable for the operation of a die set that is advanced from within the lower ram and abuts against the locking recess of the yoke plate to be connected to the yoke plate in a fixed state by advancing from within the lower ram. The gap adjusting screw was connected to a rotation driving means provided on the lower end side of the lower ram via a connecting shaft through which the shaft center of the lower ram was inserted so as to be screwed vertically to and from the position. Powder molding pre which is characterized by .