JP2001096397A - Driving system in press machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving system suitable for a hydraulic press machine or the like which is capable of high speed processing and high stroke cycles, less energy consumption, and optionally setting process speed, stroke and press output. SOLUTION: A first cylinder 3 is fixed to the slide 2 in its base and axially shaping a pressurising 30 chamber with the bottom from the top end. A second cylinder 4 is put over the first cylinder 3 so as to shape a pressurizing chamber 40 of variable capacity covering the top and outside of the first cylinder 3. A piston 10 having a screw shaft is inserted in the pressurizing chamber 30. When the piston is needed to be pushed down rapidly, the screw nut 7 which is screwed on screw shaft 11, is driven to revolve in the normal direction by an actuator 9, and during the pressure process the pressed oil is made to flow from the pressure room 30 to the pressure room 40 of variable capacity through hydraulic circuit connecting the both pressure room 30, 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device suitable for a press machine for plastic working of metal and nonmetal material.

[0002]

2. Description of the Related Art Generally, a press is widely used as a means for plastically processing a metal and a nonmetallic material. As a drive device for such a press, a crank drive device as shown in FIG. 1 and a hydraulic drive device as shown in FIG. 2 are mainly used. The basic drive principle of the former drive device uses a flywheel, accumulates energy in the process of raising and lowering the press, and outputs the stored energy by reducing the number of revolutions of the flywheel in the process of pressing, Is to process. The latter hydraulic drive device drives a motor, transmits the driving energy to a hydraulic cylinder via a hydraulic device (a hydraulic circuit) such as a hydraulic pump and a relief valve, and drives the press by the hydraulic cylinder.

[0003] The crank type driving device is characterized in that the processing speed and the number of strokes are higher and the consumable energy can be reduced as compared with the latter hydraulic device. However, since the press is driven by using inertial energy, the press processing is performed. There is a problem that the force, the processing speed, the stroke position, and the like cannot be arbitrarily set. On the other hand, the hydraulic drive device has the advantage that the working speed and stroke of the press can be set arbitrarily and the output of the press can be set arbitrarily.However, the pressurized oil from the pump is controlled by a relief valve, Since the output is controlled and the speed is controlled by the throttle valve, not only is a large amount of drive energy consumed, but the consumed drive energy becomes heat, which reduces the stability of the hydraulic system and adds additional cooling equipment. Therefore, there is a problem such as an increase in size.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made by research to eliminate the above-mentioned conventional problems, and its object is to provide a high processing speed and a high number of strokes and a high consumption rate. An object of the present invention is to provide a driving device which can be set arbitrarily with low energy, can set a processing speed, a stroke and an output of a press, and is suitable for a hydro-type press and the like.

[0005]

According to the present invention, there is provided a first cylinder having a lower portion fixed to a slide and having a pressurized chamber formed with a bottom from an upper end in an axial direction.
A second cylinder externally crowned by a first cylinder so as to define a variable volume pressurized chamber between the top and the outer periphery of the cylinder, and a second cylinder inserted into the pressurized chamber from the second cylinder. A screw shaft having a coaxial piston, a drive mechanism including a nut disposed on the upper part of the second cylinder and screwing with the screw shaft, an actuator for driving the nut to rotate forward and reverse, and the variable volume First and second hydraulic passages connecting the pressurizing chamber and the bottomed pressurizing chamber, and a full oil valve mechanism for replenishing oil when the volume of the variable volume pressurizing chamber is increased. Basic features.

A preferable example of the actuator is a numerical control type actuator such as an AC servomotor. The hydraulic circuit includes a check valve in which the first hydraulic passage allows only the flow of oil from the pressurizing chamber of the first cylinder to the pressurizing chamber of the second cylinder, and the first hydraulic passage includes the second hydraulic passage. It is preferable to provide a check valve that allows only the flow of oil from the pressurizing chamber of the cylinder to the pressurizing chamber of the first cylinder. Alternatively, the hydraulic circuit may be of a type having a single hydraulic passage connecting the pressurizing chambers and the pressurizing chamber, and including a control valve operated by an opening / closing actuator in the hydraulic passage. It is preferable that the slide is always given a lifting force by a lifting cylinder.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIGS. 3 to 6 show a first embodiment of a driving device in a press according to the present invention. Reference numeral 1 denotes a bed and reference numeral 2 denotes a slide facing the bed 1. The upper die is attached to a lower die (not shown) attached to the bed 2. Reference numeral 3 denotes a first cylinder coupled to the upper portion of the slide 2 by a fixture 18. The first cylinder 3 has a columnar shape and is provided with a cylindrical pressure chamber 30 having a required depth from the top surface on the axis. In addition, a collar portion 31 for retaining is formed on an outer portion near the top.

Reference numeral 4 denotes a second cylinder, which has a recessed portion 400 between the top and the outer periphery of the first cylinder 3 so as to form a pressurizing chamber 40 having a variable volume. The inlet 400 is fitted around the first cylinder 3. The second cylinder 4 is firmly fixed to the upper frame F such as a crown portion of a press. Second cylinder 4
A cylindrical seal block 41 that can be brought into contact with the flange 31 of the first cylinder 3 is fitted and fixed to the opening of the concave portion 400.

Reference numeral 5 denotes a support fixedly mounted on the top of the second cylinder 4. A nut 7 is rotatably supported on the support 5 via a bearing 6. The nut 7 is connected to the output side of an external numerically controlled actuator 9 via a speed change means 8 using a worm or the like. As the numerical control type actuator 9, an AC servomotor is preferable.

Reference numeral 10 denotes a piston inserted through the bottom wall of the second cylinder 4 into the pressurizing chamber 30 of the first cylinder 3. The piston 10 has a screw shaft integrally or integrally therewith. The screw shaft 11 is screwed with the nut 7. As the screw shaft 11, for example, a ball screw is suitable.

Reference numeral 12 denotes a first hydraulic passage, one end of which communicates with the pressurizing chamber 30 and the other end of which communicates with the pressurizing chamber 40. A check valve 120 that allows conduction is connected. Reference numeral 13 denotes a second hydraulic passage, one end of which communicates with the pressure chamber 40 and the other end of which communicates with the pressurization chamber 30. Check valve 130 is connected. In this example, a part of the first hydraulic passage 12 and the second hydraulic passage 13 is a common oil passage, and a pressure sensor 14 is connected to the common oil passage. The output side of the pressure sensor 14 is connected to a controller (CPU) 19 for the actuator 9. The first
The hydraulic passage 12 and the second hydraulic passage 13 are configured as internal passages in this example, but may be external passages.

Reference numeral 15 denotes an oil filling valve mechanism,
, A low-pressure accumulator 151 connected thereto, and an opening / closing device 152 for the profile valve 150. The opening / closing device 152 is, for example, an arbitrary type such as a hydraulic cylinder driving type and a motor driving type. Reference numeral 16 denotes a position sensor arranged near the slide 2, which is constituted by, for example, a magnetic sensor or the like, and whose output side is connected to the controller (CPU) 19. Reference numeral 17 denotes a cylinder for constantly urging the slide 2 upward, and for raising the slide 2 after it is lowered, for example, a gas pressure cylinder.
In the cylinder, a tube is fixed to the bed side or suspended on the slide 2, and a rigid body is provided on the bed side to contact the tube.

FIG. 7 shows a second embodiment of the present invention.
In the second embodiment, the hydraulic circuit includes a pressurizing chamber 4
A single hydraulic passage 13 'connecting the pressure chamber 30 and the pressure chamber 30 is used. The control valve 13 is provided in the hydraulic passage 13 '.
0 ', for example, a pilot check valve is interposed.
The control valve 130 'is provided with an opening / closing operation device 131. The opening / closing operation device 131 is, for example, any type such as a fluid pressure cylinder driving type and a motor driving type. A pressure sensor 14 is connected to the hydraulic passage 13 ′, and an output side of the pressure sensor 14 is connected to a controller (CPU) 19 for the actuator 9. The opening / closing operation device 131 is connected to the controller (CPU) 19.
Is connected, and the operation is controlled by this signal. The other configuration is the same as that of the first embodiment, so that the same components are denoted by the same reference numerals and description thereof will be omitted.

Next, the operation of the driving device in the press of the embodiment will be described. FIG. 3 shows a state of the ascending limit position,
The slide 2 is pushed up by the ascending cylinder 17, the screw shaft 11 and the piston 10 are stopped at the upper limit position, the volume of the pressurizing chamber 30 is large, and the volume of the pressurizing chamber 40 is small. Is satisfied. In order to start press working from this state, a signal is sent from the controller 19 to the actuator 9 to rotate the actuator 9 forward. In this case, the rotational torque causes the transmission mechanism 8 to rotate the nut 7, so that the screw shaft 11 screwed with the nut 7 moves (downs) in the axial direction without rotating. As a result, the piston 10 integrated with the screw shaft 11 is
The cylinder 2 is pushed down through the oil of 0, and the slide 2 is lowered.

When the press is lowered, the driving force of the slide is small.
0 is less than the spring force that biases the valve in the closing direction, so that the check valve 120 is kept closed. Also,
Since the check valve 130 of the first hydraulic passage 13 is maintained in a closed state by the hydraulic pressure applied to the spring, the first hydraulic passage 12 and the pressurizing chamber 40 do not communicate with each other. Therefore, the pressurized oil does not move from the pressurizing chamber 40 to the pressurizing chamber 30, and the pressurizing chamber 30 of the first cylinder 3 is sealed, and the piston 10
, The first cylinder 3 and the slide 2 are lowered. That is, the slide 2 descends at a high speed corresponding to the descending speed of the screw shaft 11. The downward movement of the slide 2 causes the piston of the ascending cylinder 17 to advance, so that the reaction force is suppressed, and ascending energy is accumulated in the ascending cylinder 17. This descending stroke is shown in FIG. 4, in which the first cylinder 3 has descended from the bottom 401 of the pressurizing chamber 40 by a distance L1. Although the volume of the pressurizing chamber 40 increases due to the lowering of the first cylinder 3,
The profile valve 150 of the oil-fill valve mechanism 15 is opened, and the oil in the low-pressure accumulator 151 is automatically supplied to the pressurizing chamber 40, so that surge is prevented, and the pressurizing chamber 40 is filled with oil.

When the lower stroke end position is reached, the mold of the slide 2 and the mold of the bed are fitted to each other, and the press reaction force increases. For this reason, the pressure of the oil in the pressurizing chamber 30 becomes higher than the spring force of the check valve 120, and the check valve 120 opens. As a result, the pressurizing chamber 30 and the pressurizing chamber 4
0 conducts through the second hydraulic passage 12, and the pressure oil automatically closes the check valve 130. Thereby, the pressurizing chamber 30
Is transmitted to the pressurizing chamber 40 via the first hydraulic passage 12. At the same time, the profile valve 150 is closed by the opening / closing device 152 of the oil filling valve mechanism 15, the low-pressure accumulator 151 and the pressurizing chamber 40 are shut off, and backflow from the latter to the former is prevented. For this reason, the hydraulic pressure in the pressurizing chamber 40 increases, and the slide 2 descends slowly due to the area difference between the pressurizing chamber 30 and the pressurizing chamber 40, and as shown in FIG. Since the processing force by the mold acts, a strong force is generated at a low speed, and a predetermined press working is performed.

Such press pressure is detected by sending a feedback signal from the position sensor 16 and / or the pressure sensor 14 to the controller 19, and when it is determined that the processing reaches a predetermined pressure or a predetermined position and the machining is completed. , A signal is sent from the controller 19 to the actuator 9. As a result, the actuator 9 starts reverse rotation, and the screw shaft 11 and the piston 10 retreat rapidly. As a result, the pressure of the pressurizing chamber 30 is increased and the pressure is reduced. At this time, the energy stored in the ascending cylinder 17 is released, and the reaction force acts on the slide 2. Cylinder starts to rise at high speed. At this time, the pressure oil in the pressurizing chamber 40 is returned to the pressurizing chamber 30 via the second hydraulic passage 13 and the check valve 130, and at the same time, the opening and closing device 152 of the oil-filling valve mechanism 15 causes the profile valve 150
Is opened, the oil in the pressurizing chamber 40 is pressed into the low-pressure accumulator 151.

When the slide 1 moves up and reaches the position of the set top dead center, the signal from the position sensor 16 is fed back to the controller 19, so that the driving of the actuator 9 is stopped, and the upper position as shown in FIG. Stop at the dead center position. Hereinafter, continuous press working is performed by repeating the above-described operations.

In the second embodiment, since the control valve 130 'is closed during the descending stroke, the pressurizing chamber 40 and the pressurizing chamber 30 are shut off as in the first embodiment. When the slide 2 descends to a position or pressure set as desired, a signal is sent from the position sensor 16 and / or the pressure sensor 14 to the controller 19, whereby a drive signal is issued from the controller 19 to the opening / closing operation device 131. As a result, the open side of the control valve 130 'is pressurized and opens. As a result, the pressure oil in the pressurizing chamber 30 is
0, and is switched from a high speed descent to a slow descent for pressurization.

When it is determined that the processing has been completed by reaching a predetermined pressure or a predetermined position, the controller 1
9 sends a signal to the actuator 9. As a result, the actuator 9 starts reverse rotation, and the screw shaft 11 and the piston 10 retreat rapidly. As a result, the pressure of the pressurizing chamber 30 is increased and the pressure is reduced. At this time, the energy stored in the ascending cylinder 17 is released, and the reaction force acts on the slide 2. Cylinder starts to rise at high speed. At this time, the pressure oil in the pressurizing chamber 40 is supplied to the pressurizing chamber 30 via the hydraulic passage 13 'and the control valve 130'.
At the same time, the profile valve 150 is opened by the opening / closing device 152 of the oil-fill valve mechanism 15, so that the oil in the pressurizing chamber 40 is pressed into the low-pressure accumulator 151. In the second embodiment, the slide 2 can be lowered and lowered at any time when the mold comes into contact with the mold, so that there is an advantage that soft touch pressing can be performed.

In the present invention, the screw shaft 1 is used during the descending stroke.
1, the pressurizing chamber 3 inside the first cylinder 3
The pressure oil of 0 is sealed and the slide 2 descends at high speed at the synchronous speed with the screw shaft 11. In the pressurizing process, even if the driving of the screw shaft 11 is continued, the hydraulic pressure in the pressurizing chamber 30 increases due to the reaction force of pressurization, and the pressurizing chamber 30 and the pressurizing chamber 40 And a large pressurizing force is generated due to the area difference between the pressurizing chamber 30 and the pressurizing chamber 40, and the slide 2
Is slowly pressurized. When the machining is completed, the screw shaft 11
Is retracted, the pressure oil in the pressurizing chamber 40 is sent to the pressurizing chamber 30, and the ascending cylinder 17 is operated to ascend at a high speed. Therefore, changes in speed and force required for press working can be smoothly realized, and moreover, instead of a pressure control method using a relief valve as in a conventional hydraulic drive device, only the energy required for each stroke is required. It is not used. It operates with a small cylinder diameter at high speed and a large cylinder diameter at pressurization to make effective use of energy. For this reason, the processing speed and the number of strokes are high, and the consumption energy can be reduced.

The working force, working speed and stroke position of the press are hydraulic,
Is of a numerical control type, it can be realized with high accuracy. In other words, not only can the press be driven with high precision, high speed, and energy saving, but it is also possible to control drawing, punching, cold forging, etc. optimally in accordance with the characteristics of each processing. It can be. Further, in the conventional hydraulic drive device, when a certain pressure is reached by using the relief valve, the pressure oil is returned to the tank, and the speed is controlled by the throttle valve. A closed circuit that connects and disconnects the two pressurizing chambers 30 and 40 with a hydraulic circuit,
The speed control of lowering, pressurizing, and raising is realized by changing the pressure receiving area to be used. Fine settings such as the pressurizing speed can be made by the CNC-controlled actuator 9 according to the processing conditions. Therefore, the operation of the slide 2 is not affected since the energy efficiency is good, the heat is not generated, and the change in the oil temperature is small. Therefore, the system is stabilized, and an oil cooler or the like for making the oil temperature appropriate is not required, so that the hydraulic circuit and the equipment can be simplified and made compact.

[0023]

According to the present invention described above, the lower pressurizing chamber 3 is fixed to the slide 2 and has a bottom from the upper end in the axial direction.
0 and a first cylinder 3 externally crowned by the first cylinder 3 so as to define a pressurizing chamber 40 having a variable volume between the first cylinder 3 having the first cylinder 3 and the top and the outer periphery of the first cylinder 3. A second cylinder 4, a screw shaft 11 coaxially having a piston 10 inserted into the pressurizing chamber 30 from the second cylinder 4,
A driving mechanism including a nut 7 screwed to the screw shaft 11 and disposed above the second cylinder 4, an actuator 9 for driving the nut 7 to rotate forward and reverse, and a pressurizing chamber 30 during a pressurizing process The hydraulic circuit for guiding the pressurized oil from the pressure chamber to the pressurizing chamber 40 and the oil filling valve mechanism 15 for supplying oil to the variable-pressure pressurizing chamber 40 when the volume of the pressurizing chamber 40 is expanded, provide a pressurizing speed and a stroke. Excellent effects such as high number, reduction of energy consumption, flexibility of setting of processing power, processing speed and stroke position, and elimination of cooling device, etc., enabling compact structure. Is obtained. According to the second aspect, since the AC servomotor is used as the actuator 9, an excellent effect that high-speed and low-speed control can be performed with high accuracy can be obtained. According to claim 3, the pressurizing chambers 30, 40 of the first cylinder 3 and the second cylinder 4 do not require an external hydraulic tank.
An excellent effect is obtained in that the pressurized oil can be smoothly moved in accordance with the descending and ascending strokes and can be efficiently used as a force. According to the fourth aspect, there is obtained an excellent effect that the soft touch can be performed by switching from the descent to the pressurization at any time by a simple hydraulic circuit.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a conventional crank type driving device.

FIG. 2 is an explanatory view showing a conventional hydraulic drive device.

FIG. 3 is a sectional view showing the first embodiment of the driving device in the press according to the present invention in an ascending limit state.

FIG. 4 is a sectional view showing a descending stroke of the device of the present invention.

FIG. 5 is a sectional view showing a pressurizing process of the apparatus of the present invention.

FIG. 6 is a cross-sectional view showing an ascending stroke of the device of the present invention.

FIG. 7 is a sectional view showing a second embodiment of the present invention.

[Explanation of symbols]

 2 Slide 3 1st cylinder 4 2nd cylinder 7 Nut 9 Actuator 10 Piston 11 Screw shaft 12 1st hydraulic passage 13 2nd hydraulic passage 13 'Hydraulic circulation passage 17 Ascending cylinder 30 Pressurization room 40 Pressurization room 120 , 130 Check valve 130 'Control valve 131 Opening / closing actuator

Claims (5)

[Claims] A first cylinder having a lower portion fixed to a slide and having a pressurized chamber having a bottom in an axial direction from an upper end.
A second cylinder 4 externally crowned by the first cylinder 3 so as to define a pressurizing chamber 40 having a variable volume between the top and the outer periphery of the first cylinder 3; A screw shaft 11 having a piston 10 coaxially inserted from the cylinder 4 into the pressurizing chamber 30, a driving mechanism including a nut 7 disposed above the second cylinder 4 and screwing with the screw shaft 11. An actuator 9 for driving the nut 7 to rotate in the forward and reverse directions is connected to the pressurizing chamber 40 having a variable volume and the pressurizing chamber 30, and pressurized oil is guided from the pressurizing chamber 30 to the pressurizing chamber 40 during the pressurizing process. A drive device for a press, comprising: a hydraulic circuit for supplying pressure to the pressure chamber 40 having a variable capacity; 2. The driving device according to claim 1, wherein the actuator 9 is an AC servomotor. 3. The hydraulic circuit has a first hydraulic passage 12 and a second hydraulic passage 13, and the first hydraulic passage 12 is
A check valve 120 that allows only oil flow from the pressurizing chamber 40 to the pressurizing chamber 30, and a check valve 120 that allows only the oil flow from the pressurizing chamber 40 to the pressurizing chamber 30.
The drive device for a press according to claim 1, further comprising: 4. The hydraulic circuit has a single hydraulic passage 13 'connecting the pressurizing chamber 30 and the pressurizing chamber 40, and the hydraulic passage 13' has a control valve 130 'operated by an opening / closing device 131. The drive device in the press according to claim 1, wherein 5. A driving device for a press according to claim 1, wherein the slide 2 is constantly applied with a lifting force by the lifting cylinder 17.