JP2516948B2 - Drive source unit of press machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a drive source unit of a press machine using an electric / displacement conversion element as a drive source.

(Prior Art) Conventionally, in a press machine, an electric motor or a hydraulic cylinder is used as a drive source for giving a reciprocating motion to a ram.

(Problems to be Solved by the Invention) However, in these conventional press machines, since a ram is reciprocally operated by an electric motor or a hydraulic cylinder, a complicated crank mechanism or a cylinder device is required,
There is a problem that the device is large-scale.

Further, in the conventional press machine, since the reciprocating motion of the ram is controlled by the clutch brake device and the hydraulic servo device, fine control is almost impossible in the former case, and finer control is possible in the latter case. There is a problem that it is not possible to perform various controls.

In the field of precision processing, it is required to process a workpiece with higher precision by controlling the ram finely.

Therefore, the present invention provides a drive source unit for a press machine that solves the above-mentioned problems, can control the operation of the ram finely with a simple structure, and can process a workpiece with high accuracy. The purpose is to do.

[Object of the Invention] (Means for Remedying Problems) In view of the conventional problems as described above, the present invention provides a container integrally provided on a mounting plate for a frame in a press machine, and a container arranged in the container. A plurality of ceramic actuators, and a lid reciprocally provided on the container for transmitting the expansion / contraction operation of the ceramic actuator to a ram in a press machine. A plurality of piezoelectric elements stacked as elements and a piezoelectric element as a pressure detection element are provided.

(Embodiment) FIG. 1 is a side sectional view of a press machine according to an embodiment of the present invention, and FIG. 2 is a plane sectional explanatory view of a drive source unit taken along the line II-II of FIG.

As shown in FIG. 1, a guide post 5 is erected between the lower bolster 1 and the upper frame 3, and a vertical direction is provided between the guide post 5 and the bolster 1 via a spring 7. A reciprocating ram 9 is guided in the. The guide post 5 is provided with a position detector (not shown) such as an encoder for detecting the height position of the ram 9.

A die 11 is fixed to the upper surface of the bolster 1 by a bolt 13. Also, on the lower surface of the ram 9, the punch holder 17
Are fixed by bolts 15. The punch holder 17
Two kinds of punches T ₁ and T ₂ are attached to the die 11 and
Is provided with holes 11a and 11b facing the punch T ₁ .
The bolster 1 is provided with a discharge port 19 and a product discharge port 21 facing the punches T ₁ and T ₂ .

A plate retainer 27 is attached to the ram 9 such that it can be lifted upward when a force is applied from below against the cushion 23 via the cushion 23 and bolts 25. The punch T ₂ is provided with an abutment G on which the workpiece W abuts.

The punch T ₁ is located at positions P ₁ and P ₂ indicated by a chain double-dashed line in FIG.
And is inserted from the right side of the drawing to perform predetermined drilling processing on two points of the workpiece W. The punch T ₂ cuts the tip of the punched workpiece W at a position P ₃ indicated by the two-dot chain line to make a product We.

A drive source unit 29 for reciprocating the ram 9 is interposed between the ram 9 and the frame 3.

The drive source unit 29 includes a rectangular frame mounting plate 31a.
The bottom of the circular container 31b is applied to the above, the ceramic actuator 33 is housed in this, a lid 31c is covered, and the lid 31c is fixed to the mounting plate 31a with a bolt 31e via a spring 31d.

The drive source unit 29 is inserted between the frame 3 and the ram 9 in a state where the ram 9 is pushed down, and is fixed to the lower surface of the frame 3 with a bolt 35.
Further, the container 31b and the lid 31c are slidable in the vertical direction, and when the ceramic actuator 33 is extended, the lid 31c is pressed downward by the lower surface of the ceramic actuator 33 to resist the spring 7. It is possible to push the ram 9 downwards.

The ceramic actuator 33 is configured by stacking piezoelectric elements, most of the stacked piezoelectric elements are used as the electric-displacement conversion element 33a, and one of them is a pressure detection element 33b.
Has been used as.

The number of laminated piezoelectric elements of the drive source unit 29 is adjusted according to the maximum reciprocating operation length (stroke) of the ram 9, and
The parallel number (9 in this example) is adjusted according to the Preston number.

As an example of the ceramic actuator, there is an example of “piezoelectric actuator” developed by Nippon Denso Co., Ltd.

According to this actuator, when a voltage of 300 to 400 V is applied to a PZT-based piezoelectric element with a thickness of 0.5 mm, a displacement of 20 to 30 μ and a force of 800 kg can be output at a super-speed of msec. 〜100, parallel number 9, displacement 1-3mm,
It can output 7.2 tons of force.

Therefore, for example, a steel plate with a tensile strength of 32 and a thickness of 0.6 mm is
In the case of cutting at 0 mm and drilling two holes with a diameter of 8 mm, a stroke of about 1 mm and a load of 1924 kg are required, so 50 layers are stacked and 9 rows are stacked (stroke length 1 mm, maximum load
A unit 29 of 7.2 tons will be sufficient. As the drive source unit 29, various types having different numbers of stacked layers and parallel numbers may be prepared and used properly according to the work.

In the press machine having the above structure, the ram 9 is lowered with the tip of the workpiece W inserted from the right side of the drawing abutting against the abutting G of the punch T ₂ , and the predetermined punching is performed at the positions P ₁ and P _2. And the product We is cut at the position P ₃ . The material feeding and the descending of the ram 9 are controlled by the synchronizing signal, and the punched products We are manufactured one after another.

FIG. 3 is a block diagram of the control device. Figure 4 is the third
FIG. 6 is a block diagram showing functions of a microprocessor 35 shown in the figure.

The control device has a microprocessor 35. The microprocessor 35 includes an input / output interface 37, ROM39, RAM41, D / A converter 43, A / D converter 4
5 is connected.

The D / A converter 43 is connected to the electric / displacement conversion element 33 of the ceramic actuator 33 via a voltage amplifier 47.
a is connected. Further, the pressure detector 33b and the position detector 49 are connected to the A / D converter 45.

As shown in FIG. 4, the microprocessor 35 is
Functionally, it has a processing condition input unit 35a, a processing pattern generation unit 35b, and a comparison / output calculation unit 35c.

The processing condition input portion 35a is made of the material of the workpiece W, the plate thickness,
Various processing conditions are input and set by key input such as a processing shape.

The processing pattern generation unit 35b is for generating an optimum processing pattern according to the input condition, based on the shear characteristic diagram shown in FIG. That is, in the shearing of a plate material such as a sheet metal, since the yield point Pa and the break point Pb are provided for the displacement as shown in the figure, the optimum processing of the displacement-velocity or the displacement-pressure is performed so that the shearing accuracy is the best. Set the pattern.
The processing pattern may be set in time-speed.

The comparison / output calculation unit 35c outputs the optimum control value (voltage) to the ceramic actuator 33 by comparing the detected values of the pressure detector 33b and the position detector 49 with the set value.

FIG. 6 is a flow chart showing the operation of the control device shown in FIG.

 In step 601, processing conditions are set.

In step 602, processing speed with respect to displacement (position),
A processing pattern such as a pressing force is generated. That is, in FIG. 5, the reaction force with respect to the displacement amount is large up to the yield point Pa,
When the yield point Pa is exceeded, the reaction force becomes smaller than the displacement.
In other words, in the initial stage of processing, the force changes greatly with respect to the unit displacement amount, but in the latter stage, a substantially constant force with respect to the unit displacement amount is sufficient. Therefore, in order to perform highly accurate shearing, optimum patterns for position, velocity, and pressure are set.

In step 603, a parameter for applying a predetermined voltage to the ceramic actuator 33 is calculated according to the machining pattern set in step 602. This parameter is set according to the unit 29.

In step 604, the ceramic actuator 33 is driven according to the parameters and trial machining is performed.

In steps 605 and 606, the machining pattern and the actual machining are compared, and if the difference between them is large, the parameters are corrected again.

In step 607, the next processing is performed according to the correction pattern. When an abnormal change occurs in the processing pattern during processing, it is judged whether the die is broken or two sheets are overlaid, and abnormal processing is executed.

As described above, according to this example, since the punches T ₁ and T ₂ can be electronically controlled in an optimum pattern according to the processing conditions, fine punching and fine blanking can be performed, and the workpiece W We can manufacture the product We with good accuracy.

Further, in this example, since the pressure detector 33d is interposed in the ceramic actuator 33, the pressure can be easily detected, and the punches T ₁ and T ₂ can be controlled by a predetermined processing pattern by the pressure feedback control. .

Further, in this example, since the arithmetic unit 35c for comparing the set machining pattern with the actual machining pattern is provided, an abnormality can be easily detected, and an opportunity to cause a defect or damage the die is provided. Is reduced.

Further, since the drive source unit 29 is easily attached to and detached from the machine body, the unit 29 can be easily replaced and optimal control can be performed according to the processing conditions.

It should be noted that the present invention is not limited to the above embodiment, but can be embodied in other modes by making appropriate design changes.

[Effects of the Invention] As will be understood from the above description of the embodiments, the present invention is, in short, the container (31b) integrally provided with the mounting plate (31a) to the frame (3) in the press machine, and the container (31b). A plurality of ceramic actuators (33) arranged in a container (31b) and a reciprocating movement in the container (31b) for transmitting expansion and contraction operations of the ceramic actuator (33) to a ram (9) in a press machine. Cover (31c)
And, the ceramic actuator (3
3) is provided with a plurality of piezoelectric elements stacked as an electric-displacement conversion element (33a) and a piezoelectric element as a pressure detection element (33b).

As apparent from the above configuration, in the present invention, the container 31b is provided on the mounting plate 31a for the frame 3 in the press machine, and the plurality of ceramic actuators 33 are housed in the container 31b. The expansion / contraction operation of the ceramic actuator 33 is performed by the ram 9 of the press machine.
A lid 31c for transmitting the power is provided so as to be capable of reciprocating. The ceramic actuator 33 has a structure in which a plurality of piezoelectric elements as electric-displacement conversion elements 33a and piezoelectric elements as pressure detection elements 33b are laminated.

Therefore, according to the present invention, it suffices to attach the mounting plate 31a to the frame 3 for the press machine, and the attachment to the press machine is easy. In addition, the expansion and contraction of the plurality of ceramic actuators
Since it is transmitted to the ram 9 via c, the contact surface becomes large, the pressures of the plurality of ceramic actuators 33 are averaged, and the ram 9 can be moved smoothly. .

Further, the ceramic actuator 33 is a pressure detecting element.
Since the piezoelectric element 33b is provided, the ram 9
It is possible to detect the pressure when the workpiece W is processed by pressing. Therefore, it is possible to perform feedback control of the pressure and to take measures such as stopping when an abnormal pressure is detected, thereby improving safety.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a press machine according to an embodiment of the present invention, FIG. 2 is an explanatory plan sectional view taken along the line II-II of FIG. 1, and FIGS. A block diagram of a machine control device, FIG. 5 is a displacement-force characteristic diagram of a plastic material, and FIG.
The figure is a flow chart showing the operation of the control device. 9 …… Ram 11 …… Die 29 …… Drive source unit 33 …… Ceramic actuator W …… Workpiece We …… Product T ₁ , T ₂ … Punch

Claims (1)

(57) [Claims] 1. A container (31b) integrally provided on a mounting plate (31a) to a frame (3) of a press machine, a plurality of ceramic actuators (33) arranged in the container (31b), A lid (31c) reciprocally provided in the container (31b) for transmitting the expansion and contraction operation of the ceramic actuator (33) to a ram (9) in the press machine;
Comprising the ceramic actuator (33)
Is a drive source unit for a press machine, comprising a plurality of piezoelectric elements stacked as electric-displacement conversion elements (33a) and piezoelectric elements as pressure detection elements (33b).