JPH06285697A - Press - Google Patents

Abstract

PURPOSE:To guarantee the quality of an article to be pressed by providing a shift prevention mechanism for preventing a die or other punch from shifting to another punch and an abnormality detection mechanism for detecting if a die or other punch shifts during the shift preventing operation. CONSTITUTION:The press is provided with a die 21 and at least a pair of punches 22, 23 which are freely slidingly engaged in the die 21 to press an article to be pressed. A shift prevention mechanism 31, 32 is provided by which, at the time of releasing the pressurizing of one punch, the die 21 or other punch is prevented from shifting to another punch. Also, an abnormality detection mechanism 41, 42 is provided by which, during the operation of the shift prevention mechanism 31, 32, whether or not the die 21 or other punch shifts to another punch is detected. Thus, the situation is prevented in which a die or other parts are shifted yet a press work is continued with a possibility of generating defects on an article to be pressed, and the quality of the article to be pressed is guaranteed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press device such as a powder molding press equipped with a lifting prevention mechanism.

[0002]

2. Description of the Related Art A powder molding press, which is a pressing device used in powder metallurgy, is a die for molding a green compact 1 and includes a die 6 and an integrated die 6 as shown in FIG. A core rod 7 located coaxially inside thereof, a lower punch 8 fitted between the die 6 and the core rod 7 in a vertically slidable manner from below, and a vertically punched space between the die 6 and the core rod 7 in a vertically slidable manner. In addition, it is provided with an upper punch 9 which is fitted so as to be freely inserted and removed. Especially, the mold shown in FIG.
In order to mold the green compact 1 with the flange 1a, a die 6
Is stepped and has an upward step surface 6a inside.

Then, for example, in the withdrawal method in a mechanical press, the mold operates as shown in FIGS. 5 and 6. FIG. 6 is an operation diagram, and the three graphs show the heights of the upper surface of the die 6, the upper surface of the lower punch 8, and the upper surface of the upper punch 9, respectively, with respect to the rotation angle of the spindle rotated by the main motor. Shows the change. Figure 6
As shown in, the lower punch 8 is fixed. First, 270 ~
Between 90 °, the raw material powder 2 is filled in the die 6 by a feeder (not shown) as shown in FIG. 5 (a). Next, at the time of 90 ° shown in FIG. 5B, the descending upper punch 9 starts to fit into the die 6, and the upper pressurization starts. Then, at the time of 113 ° shown in FIG. 5C, the die 6 which has been stopped until then starts to descend integrally with the upper punch 9, and the upper pressing is completed and the lower pressing starts. Then, at 180 ° shown in FIG. 5D, the die 6 and the upper punch 9 are stopped, and the lower pressurization is completed. In this way, the raw material powder 2 is compressed by the punches 8 and 9 in the die 6, and the green compact 1 is molded. After 180 °, the upper punch 9 starts to rise, and at 228 °, the die 6 starts to descend. As a result, the green compact 1 is extracted from the die 6, but at the time of 270 ° shown in FIG. 5 (e), the die 6 is stopped and the extraction is completed.

By the way, when the upper punch 9 starts to move up after the time point of 180 °, the die 6 is restored because the bending which has been caused by the downward pressurization of the upper punch 9 is restored. I try to surface. This is remarkable in presses using toolsets, which have become mainstream in recent years. While the lower punch 8 is fixed, when the die 6 floats, in the case of the green compact 1 with the flange 1a formed by using the stepped die 6 as shown in FIG. Since only the die 1a is pushed up by the die 6, the base portion 1b of the flange 1a is easily cracked. When molding a green compact with a flange, the lower punch is divided into a lower first punch and a lower second punch for the purpose of making the density uniform, and the lower first punch on the outer peripheral side for molding the flange. Is used as a floating punch, and the lower second punch on the inner peripheral side is also used as a fixed punch. At the time of ejection, the lower first punch starts descending after the die starts descending. In this way, the flange of the green compact is extracted between the start of the lowering of the die and the start of the lower first punch, and then the other part of the green compact is extracted by the second lower punch. At any rate, when the upper punch starts to move up after the completion of pressurization, the lifting of the lower first punch also becomes a problem.

Therefore, conventionally, powder molding presses have been
A floating prevention mechanism is provided to prevent the die and the floating punch from floating from the start of the ascending of the upper punch to the end of the lowering of the die, for example, from 180 ° to 270 ° in FIG. It should be noted that the lifting prevention is canceled by the time the die starts to rise again. Without such a lifting prevention mechanism, the die 6 floats as shown by the broken line in FIG. 6, but if the lifting prevention mechanism is provided, the lifting of the die 6 can be prevented as shown by the solid line. As the lifting prevention mechanism, various structures have been conventionally used. For example, as described in Japanese Patent Publication No. 58-11320, there is one in which a lower ram integrated with a die is pressed downward by a fluid pressure cylinder. Also, Japanese Examined Sho 57-37440
As described in Japanese Patent Publication, a wedge body that is interlocked with a main shaft of a press through a crank mechanism and a cam is provided, and the wedge body is further pressed by an air cylinder, and an extrusion plate integrated with a die is attached from above. Some hold it down. Furthermore, Japanese Patent Publication No. 3-56837 and Japanese Patent Publication No. 2-42
As described in Japanese Patent No. 598, there is also one in which a lower ram integrated with a die or a middle plate integrated with a lower first punch is pressed from above by a push-down pin which moves up and down in accordance with the rotation of a cam provided on a main shaft. is there.

[0006]

However, in general,
The lifting prevention mechanism as described above can reliably operate when the press speed is slow, but may not be able to reliably follow when the press speed is high, and with the rise of the upper punch after the completion of pressurization, The die and floating punch may rise. In particular, although there are few problems in a mechanical mechanism that uses a cam or the like that follows the main shaft, in a device that uses a hydraulic cylinder, a problem is likely to occur in followability. However, in the past, there was no means to confirm whether or not the floating prevention mechanism was operating reliably.Therefore, although there was a lifting prevention mechanism, the die and floating punch were actually lifted, and molding was not performed. There was a risk that the pressing operation could be continued while there was a possibility that defects would occur in the green compact.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a press device capable of confirming whether or not the rising prevention mechanism is operating reliably.

[0008]

In order to achieve the above-mentioned object, a pressing device according to the present invention has a die and at least a pair of members which are slidably fitted in the die to press an object to be pressed. Punch, a lift preventing mechanism for preventing the die or the other punch from moving toward the one punch when the pressure applied by the one punch is released, and the above-mentioned lift preventing mechanism during operation of the lift preventing mechanism. And an abnormality detecting mechanism for detecting whether or not the die or another punch is moving toward the one punch.

Further, according to the press apparatus of the invention of claim 2,
The abnormality detection mechanism has a rotary encoder having a rotor that is in contact with a member integrated with the die or another punch and rotates according to the movement of this member, and the movement of the die or another punch by the output from this rotary encoder. And a movement amount determination means for determining the amount.

[0010]

In the pressing apparatus according to the first aspect of the present invention, the object to be pressed is pressed by at least a pair of punches in the die. The prevention mechanism prevents the die or other punch from moving towards the one punch. Moreover, when the floating prevention mechanism operates, the abnormality detection mechanism detects whether the die or another punch is moving toward one punch. As a result, if the moving amount of the die or other punch is larger than a predetermined value, an alarm is issued or the pressing device is stopped.

Further, in the press device according to the second aspect of the present invention, the abnormality detecting mechanism includes a rotary encoder and a movement amount determining means, and when a member integrated with the die or another punch moves, it comes into contact with this member. The rotary encoder rotor is rotating. Then, the movement amount determination means determines the movement amount of the die or another punch based on the output from the rotary encoder.

[0012]

EXAMPLES An example of the powder molding press of the present invention will be described below with reference to FIGS. The powder molding press of this embodiment uses a tool set 12 that is detachably attached to a press body 11. 1 and 2, 13 is a bed on the press body 11 side, and 14 is a lower ram. Although not shown, the lower ram 14 is biased upward by, for example, a hydraulic cylinder,
The power is transmitted downward from the main shaft of the press via a cam or the like to move up and down. Meanwhile, the toolset 12
A plurality of guide rods 16 are vertically fixed on a yoke plate 15 to which the lower ram 14 is fixedly connected, and a die plate 17 is horizontally fixed to the upper ends of these guide rods 16. A base plate 18 is horizontally and vertically movably supported by the guide rod 16 above the yoke plate 15, and a middle plate 19 is horizontally above the base plate 18. And it is supported so that it can move up and down. Base plate 18
Is fixed on the bed 13. further,
Although not shown, the middle plate 19 is interlocked with the other plates 13, 15, 16 by an interlocking mechanism including a wedge, a sliding block, a stopper and the like. The cylindrical die 21 is vertically fixed to the die plate 17 in a penetrating state. Further, a cylindrical lower first punch 22 which is a floating punch is fixed on the middle plate 19, and the lower first punch 22 is vertically slidably fitted in the die 21. . Also,
A cylindrical lower second punch 23 is vertically fixed on the base plate 18, and the lower second punch 23 is vertically slidably fitted in the lower first punch 22. Further, a core rod 24 is vertically fixed on the yoke plate 15, and the core rod 24 is vertically slidably fitted in the lower second punch 23. In addition, 25 is a vertical cylindrical upper punch, and this upper punch 25 is the press body.
It is fixedly connected to an upper ram 11 (not shown), moves up and down, and is fitted into the die 21 so as to be insertable and removable from above.

Further, the lower ram 14 and the middle plate
For 19, the die 21 and the lower first punch 22 are prevented from floating when the upper punch 25 starts to rise, that is, when the pressure applied to the green compact 1 by the upper punch 25 is released. Lifting prevention mechanisms 31, 32 are provided respectively. Although not shown in detail, the lifting prevention mechanisms 31 and 32 are composed of, for example, a rod that moves up and down according to the rotation of a cam fixed to the main shaft of the press, and when the pressurization is completed (at a point of 180 ° in FIG. 6). ) To the time point when the die 21 and the first lower punch 22 reach the lower limit position (the time point of 270 ° in FIG. 6), the lower ram 14 and the middle plate 19 are pressed from above.

Further, the present powder molding press is provided with abnormality detecting mechanisms 41 and 42 for detecting whether or not the die 21 and the lower first punch 22 are floating when the floating preventing mechanisms 31 and 32 are operated. ing. Next, the abnormality detection mechanisms 41 and 42 will be described from the abnormality detection mechanism 41 for the die 21. A detection plate 43 is fixed to the yoke plate 15 integrated with the die 21. On the other hand, on the press body 11 side, a rotary encoder (for example, E6 manufactured by OMRON
C-CWZ) 44 is provided, and a rotor 45 having a horizontal rotation axis direction of the rotary encoder 44 contacts the detection plate 43. Further, the rotary encoder 44 is connected to a preset counter (for example, H7AN-E4D made by OMRON) 46 as a movement amount determination means for determining the amount of rise of the detection plate 43 based on the output from the rotary encoder 44. The preset counter 46 counts the count signal output from the rotary encoder 44, and performs a predetermined output when the count value reaches a preset value set in advance. As a result, it is determined whether or not the amount of rise of the detection plate 43 has become equal to or larger than the predetermined reference value of 0.2 mm. The output of the preset counter 46 is input to the control means 47 and the notification means 48. Based on the output from the preset counter 46, the control means 47 stops the operation of the powder molding press when the lift amount of the detection plate 43 becomes the reference value or more during the operation of the floating prevention mechanisms 31 and 32. .
Further, when the amount of rise of the detection plate 43 becomes equal to or larger than the reference value, the notifying means 48 similarly notifies that effect by means of a buzzer or a lamp. A reset signal or the like is output from the control means 47 to the preset counter 46 according to the rotation angle of the spindle. On the other hand, the abnormality detection mechanism 41 for the lower first punch 22 also
Detection plate 51 fixed to middle plate 19 integrated with
And a rotary encoder 53 having a rotor 52 in contact with the detection plate 51, and a preset counter 54. The preset counter 54 is connected to the control means 47 and the notification means 48.

Next, the operation of the above configuration will be described. First, as shown in FIG. 2A, the upper punch 25
The raw material powder 2 is filled in the die 21 by a feeder (not shown) in a state where the raw material powder 2 is pulled upward from the die 21.
After the raw material powder 2 is filled, the upper punch 25 descending moves to the die 21.
It is fitted inside, and the upper pressure is applied first. After that, the die 21 and the lower first punch 22 that have been stopped until then start descending integrally with the die 21, and the lower pressurization is performed. At this time, first, the die 21 starts to descend, and then the lower first punch 22 starts to descend. Then, the upper punch 25, the lower first punch 22 and the die 21 are once stopped and the pressurization is completed. Figure 2
(B) has shown the time of completion of pressurization. In this way, the raw material powder 2 is compressed by the punches 22, 23, and 25 in the die 21, and the green compact 1 that is the object to be pressed is molded. After the pressurization is completed, the upper punch 25 immediately rises, but the die 21 and the lower first punch 22 stop for a while. And first, die 21
Starts to descend, and then the lower first punch 22 starts to descend integrally with the die 21. As shown in FIG. 2 (c), these dies
21 and the lower first punch 22, the upper end thereof is the lower second punch 23.
Down to the same height as the upper end of the
Is removed from the die 21. This extracted green compact 1
Are also dispensed by the feeder. Also die
After reaching the position shown in FIG. 2C, the lower punch 21 and the lower first punch 22 start to rise. The above steps are repeated, and the green compact 1 is molded one after another.

By the way, when the pressurization is completed (180 in FIG. 6)
Time point) to the time point when the die 21 and the lower first punch 22 reach the lower limit position (time point at 270 ° in FIG. 6).
Lifting prevention mechanism 31 and 32 are lower rams integrated with die 21
A downward force is applied to the middle plate 19 integrated with the lower first punch 22 and the lower punch 14. As a result, the die 21 and the lower first punch 22 are prevented from being lifted up against the release of the pressure by the upper punch 25, and the base portion 1b of the flange 1a is prevented from being cracked.

When the floating prevention mechanisms 31 and 32 are operated, whether or not the die 21 and the lower first punch 22 are floating is detected by the abnormality detection mechanisms 41 and 42, respectively.
That is, as shown in FIG. 3, when the pressurization is completed (at 180 ° in FIG. 6), the preset counter 46,
54 is reset. From this reset, the count signals from the rotary encoders 44 and 53 are counted. If the die 21 and the lower first punch 22 are floated, the detection plates 43 and 51 are lifted to rotate the rotors 45 and 52 of the rotary encoders 44 and 53 which are in contact therewith, Along with the rotation, the rotary encoders 44 and 53 output counting signals. Preset counter 46, 54
The counted value by means of corresponds to the amount of rise of the die 21 and the lower first punch 22. Then, at 205 ° when the die 21 is still stopped shortly after the upper punch 25 starts to rise, the count value is compared with the preset value set in advance. That is, the measured rise amounts of the die 21 and the lower first punch 22 are compared with the reference value. Here, if the amount of increase is smaller than the reference value, the powder molding press continues to operate as it is, but if the amount of increase is more than the reference value, the operation of the powder molding press is stopped and a buzzer or a lamp indicates that there is an abnormality. Notification is given.
The reference value is 0.2 mm, but if the amount of rise is less than 0.2 mm, no inconvenience such as cracking in the green compact 1 occurs. On the other hand, in the case of 0.2 mm or more where cracks may occur, the powder molding press is stopped and the fact that an abnormality has occurred is notified, and thereafter molding of defective products is prevented. Become.

As described above, according to the configuration of the above-described embodiment, the abnormality detection mechanisms 41, 42 enable the floating prevention mechanism 31,
You can check whether 32 is working properly. When the die 21 and the lower first punch 22 have floated above the reference value when the pressure applied by the upper punch 25 is released,
This is detected by the abnormality detection mechanisms 41 and 42, and the operation of the powder molding press is stopped. Therefore, it is possible to prevent the press work from being continued while there is a possibility that the green compact 1 to be molded may be defective, and the powder compaction molding can be performed. The quality of the green compact 1 can be guaranteed. Further, the abnormality detection mechanisms 41 and 42 are the rotary encoder 4
Since it is composed of 4, 53 and preset counters 46, 54, the structure is simple and high reliability can be obtained.

The present invention is not limited to the above embodiment, and various modifications can be made. For example,
The powder molding press of the above-mentioned embodiment, as a mold, a die 21,
The lower first punch 22, the lower second punch 23, the core rod 24, and the upper punch 25 are provided, but the invention is not limited thereto. Then, for example, in the case where there is only one lower punch and it is fixed, the floating prevention mechanism and the abnormality detection mechanism are provided only for the die.

[0020]

According to the first aspect of the present invention, there is provided a floating preventing mechanism for preventing the die or another punch from moving toward the one punch when the pressure applied by the one punch is released. In the provided press device, an abnormality detection mechanism for detecting whether or not the die or another punch is moving toward the one punch when the floating prevention mechanism is operated is provided, so that the floating prevention mechanism can be reliably operated. It is possible to confirm whether or not it is operating.Therefore, it is possible to prevent the press work from being continued while the die or the like is actually lifted up, and there is a possibility that the object to be pressed may be defective. The quality of pressed products can be guaranteed.

Further, according to the invention of claim 2, the abnormality detecting mechanism is constituted by the rotary encoder and the movement amount judging means for judging the movement amount of the die or the other punch by the output thereof. The structure of the mechanism is simple, and its reliability can be increased.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a pressing device of the present invention.

FIG. 2 is a cross-sectional view showing the same operation.

FIG. 3 is a flowchart of the same as above.

FIG. 4 is a cross-sectional view showing an example of a die including a stepped die.

FIG. 5 is a cross-sectional view showing the operation of the mold in the withdrawal method.

FIG. 6 is an operation diagram of the above.

[Explanation of symbols]

 1 Powder compact (object to be pressed) 21 Die 22 Lower first punch (Punch) 23 Lower second punch (Punch) 25 Upper punch (Punch) 31 Lifting prevention mechanism 32 Lifting prevention mechanism 41 Abnormality detection mechanism 42 Abnormality detection Mechanism 43 Detection plate (member integrated with die) 44 Rotary encoder 45 Rotor 46 Preset counter (movement amount determination means) 51 Detection plate (member integrated with punch) 52 Rotor 53 Rotary encoder 54 Preset counter (movement amount determination means) )

Claims (2)

[Claims] 1. A die, at least a pair of punches that are slidably fitted in the die and pressurize an object to be pressed, and a die or another punch when the pressure applied by one punch is released. A lift prevention mechanism for preventing the punch from moving toward the one punch, and an abnormality that detects whether the die or another punch is moved toward the one punch when the lift preventing mechanism is operated. A press device comprising a detection mechanism. 2. The abnormality detecting mechanism includes a rotary encoder having a rotor which is in contact with a member integrated with the die or another punch and rotates with the movement of the member, and the die from the output from the rotary encoder. The press apparatus according to claim 1, further comprising a movement amount determination unit that determines a movement amount of another punch.