JP2002103090A - Press device actuator and control method therefor - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the load on the mold by reducing the load loss and to shorten the moving time of the actuator required in one cycle to improve the operation efficiency. SOLUTION: A pressure ram 4 is directly reciprocated by a ball screw mechanism 17 operated by a servomotor 13, and a moving speed before and after a pressure step is made high. The bottom dead center of the pressurizing ram 4 is set to a position beyond the actual bottom dead center that stops due to mold contact, and after the pressurizing ram 4 reaches the actual bottom dead center, pressurizes to the set bottom dead center. As the ram 4 attempts to descend, the current value of the servo motor 13 increases, and a pressurizing torque is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to, for example, a press machine for processing a thin plate, and an actuator for raising and lowering a pressurizing ram of the pressurizing device and pressurizing a mold via the pressurizing ram and its control About the method.

[0002]

2. Description of the Related Art As a pressing device used for pressing a thin plate, an upper die is attached via a pressure ram to a tip of an actuator which can be moved up and down, and is sandwiched between the upper die and a lower die on a fixed side. There is a type in which a work is pressed by a pressure ram by lowering an actuator. Many actuators provided in such press devices use a hydraulic drive source, and for example, stroke control is performed on a magnescale. Further, there is a type in which a servomotor is used as a drive source. For example, a type is known in which a servomotor and a cam are combined, and the pressure output and position are controlled by controlling the shape of the cam and the phase of the servomotor.

[0003]

In the conventional actuator, it is difficult to finely set the pressing load with high accuracy. In practice, a considerable extra load is applied to the mold so that the processing can be performed reliably. It is the present situation. For this reason, the burden on the mold was large, and the service life was short. Also,
In order to secure a space for loading and unloading the work between the upper and lower dies, the stroke of the actuator is often set to be long. For this reason, the operation time other than pressurization in one cycle is long, and the operation efficiency was not good.

Accordingly, the present invention can prolong the service life of a mold by reducing the load loss and reducing the load on the mold, and shorten the operation time required in one cycle to reduce the operating efficiency. An object of the present invention is to provide an actuator for a press device and a control method thereof that are improved.

[0005]

According to the present invention, there is provided an actuator for a press device, comprising: a ball screw mechanism in which a ball screw nut is screwed into a ball screw; Motor and a ball screw nut that are integrally connected to each other to make it reciprocally movable together with the ball screw nut. A pressure ram is attached to the tip of the actuator body, and a guide that guides the reciprocating motion of the actuator body. A power supply for supplying electricity to the motor, and control means for controlling the current value of the motor and the position of the actuator body.

According to the actuator having the above configuration, the reciprocating speed of the actuator body can be arbitrarily adjusted according to the number of rotations of the motor. Therefore, the reciprocating movement from the standby position, which is the start / end position, to immediately before the bottom dead center where the die contacts the die can be performed at a high speed, and the operation time required for other than pressurization in one cycle can be reduced. . As a result, operation efficiency is improved. Also, if the set bottom dead center, which is the stroke end of the actuator body, is set to a position beyond the actual bottom dead center where the mold hits the mold, the actuator body tries to move to the set bottom dead center after the mold hits. Therefore, the current value of the motor increases, and a pressurizing torque is generated. By appropriately setting the set bottom dead center and the holding time, it is possible to apply pressure with a minimum load. As a result, the load on the mold is reduced with less load loss, and the service life of the mold can be extended.

[0007] The actuator of the present invention has the following configurations as preferred modes. First, a servomotor is applied as a motor. Since the servo motor can accurately control the number of rotations and the rotation angle, the position and speed of the actuator can be easily and accurately controlled.

Next, a guide for guiding the reciprocating motion of the actuator main body is constituted by a cylindrical body coaxially arranged around the actuator main body, and further, within a range where the outer peripheral edge of the cross section is projected. Place pressure ram. According to this aspect, even if the position where the reaction force generated at the time of pressurization is eccentric with respect to the pressurizing ram, the reaction force is directed into the outer peripheral edge of the guide, and the eccentric load is received by the guide. Can be Therefore, an uneven load on the actuator body, the ball screw, or another component receiving the load, and deformation accompanying the load are suppressed, and the life of the device is prolonged.

Next, a reaction force receiving member is provided between the motor and the ball screw for receiving all of the reaction force received from the pressurizing ram from the ball screw and blocking transmission of the reaction force to the motor. Examples of the member include a thrust bearing supported by a support member other than the motor. According to this embodiment, since the reaction force generated at the time of pressurization is not transmitted to the motor, there is no possibility that the operation of the motor is hindered or the drive shaft of the motor is damaged.

Next, according to the method of controlling an actuator for a press device of the present invention, the set bottom dead center, which is the stroke end of the actuator body, is set to a position beyond the actual bottom dead center where the mold hits the mold. From the actual bottom dead center, set the holding time of the pressurizing torque generated by the motor trying to rotate until the current value according to the set bottom dead center, and further, just before the actual bottom dead center , The deceleration position and the acceleration position are set, and the actuator body is moved forward at a high speed from the start / end position of the standby position to the deceleration position, and then moved forward at a low speed to the actual bottom dead center. Then, the motor is driven to move further to the set bottom dead center to generate a constant pressurizing torque, and after the holding time elapses, the motor is rotated reversely to return to the acceleration position at a low speed, and thereafter To the standby position It is characterized in that is backward at high speed.

According to the above control method, the above-mentioned effects, that is, the load loss is small and the burden on the mold is reduced, so that the service life of the mold can be extended and the operation required in one cycle can be performed. This has the effect of shortening the time and improving the operation efficiency.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a thin-plate processing press device equipped with an actuator according to one embodiment. In the figure, reference numeral 1 denotes a press device main body, 2 denotes a bolster, 3 denotes a tie rod, and an actuator 10 is set on the press device main body 1. The actuator 10 includes an actuator body 11 that goes up and down through the press device body 1, and a disc-shaped pressure ram 4 is attached to a lower end of the actuator body 11. An upper die 5 is fixed to the pressing ram 4, and the upper die 5 is fixed to the bolster 2.
And a lower mold 6 constituting a mold is set.

A work (not shown) is sandwiched between upper and lower dies 5 and 6, and is processed by the pressurizing ram 4 which is lowered by the actuator body 11. Actuator 10
Uses a servo motor 13 having an encoder 12 as a drive source. The encoder 12 and the servo motor 13 are connected to a servo amplifier (power supply, control means) 14 having a built-in controller. A sequencer 15 as a device is connected.

Referring to FIG. 2, the actuator 10 will be described in detail. Reference numeral 16 in FIG. 2 denotes a cylindrical guide fixed on the press device main body 1, and the cylindrical actuator main body 11 is inserted into the guide 16 so as to be able to move up and down. Inner peripheral surface of guide 16 and actuator body 11
A rectangular spline is formed on the outer peripheral surface of the actuator body 11 so as to extend in the axial direction and slidably engage with each other, so that the actuator body 11 cannot rotate around the axis with respect to the guide 16 and moves up and down in the axial direction. It is free.

The actuator body 11 has an upper end connected to a ball screw mechanism 17. The ball screw mechanism 17 includes a ball screw 18 and a ball screw nut 19 screwed into the ball screw 18 via a ball (not shown).
The ball screw nut 19 is fitted to the upper end of the actuator body 11 and is integrally fixed. The upper end of the ball screw 18 is rotatably supported by a housing 21 via a thrust bearing (reaction force receiving member) 20. The housing 21 is supported by a plurality of tie rods 22 erected on the guide 16. The upper end of the ball screw 18 passes through the housing 21, and a coupling 23 provided at the upper end is connected to a coupling 24 provided on the drive shaft 13 a of the servomotor 13.

According to the ball screw mechanism 17, when the ball screw 18 is rotated by the servo motor 13, the actuator body 11 moves up and down along the guide 16 via the ball screw nut 19. The actuator body 11, the guide 16 and the pressure ram 4 are coaxially arranged, and the outer diameter of the guide 16 is larger than that of the pressure ram 4. In other words, the pressing ram 4 is arranged within a range (in the line R in FIG. 2) in which the outer peripheral edge of the cross section of the guide 16 is projected.

The pressure ram 4 is attached to the lower end of the actuator body 11 via an overload protector 25. The overload protector 25 applies a maximum load set to the disc spring to the disc spring and applies a maximum load to the disc spring to elastically deform the disc spring. And a flexure sensor 26 for detecting that a contra-force (load) exceeding the maximum load is applied to the disc spring and that the flex sensor is bent. Is detected, a sensing signal is supplied to the servo amplifier 14,
The servo motor 13 stops. The reaction force generated at the time of pressurization is transmitted from the pressurization ram 4 to the overload protector 25, the actuator body 11, the ball screw nut 19, and the ball screw 18 in this order, and passes through the thrust bearing 20 to the housing 21 supported by the tie rod 22. And is not transmitted to the servo motor 13.

The tie rod 22 detects the position of the ball screw nut 19 and detects the position of the ball screw nut 19.
A pair of upper and lower overrun sensors 27 are provided for preventing overruns on the descending side and the ascending side. The overrun sensor 27 allows the actuator body 11
Is detected, the detection signal is supplied to the servo amplifier 14 and the servo motor 13 stops.

Next, a preferred control method of the actuator 10 and an operation based on the method will be described. This control is performed when the work is plastically worked. Servo amplifier 1 for controlling the rotation speed and rotation speed of servo motor 13
In step 4, the following parameters required for one cycle (down-press-up) are set. Bottom dead center, which is the stroke end of the actuator body 11. The bottom dead center is set slightly lower than the actual bottom dead center where the upper mold 5 hits the lower mold 6. The holding time during which the current value of the servomotor 13 increases and the pressing torque is applied after the actuator body 11 reaches the actual bottom dead center. The deceleration position and the acceleration position, which are positions immediately before the actual bottom dead center of the actuator body 11. Elevating speed of actuator body 11

FIG. 3 shows the relationship between the position of the actuator body 11 and the pressure ram 4 and the time according to this control. First, when a start signal is input to the servo amplifier 14 by a host command from the sequencer 15, the servo motor 1
3, the actuator body 11 lowers the pressure ram 4 at a high speed from a standby position, which is a start / end position. When it is lowered to the deceleration position, the speed is changed to a low speed and further lowered, and the upper die 5 hits the lower die 6 and the pressing ram 4 stops. The servo motor 13 attempts to rotate so that the pressurizing ram 4 moves down to the set bottom dead center, but cannot press down due to the mold, so that the current value increases and pressurizing torque is generated. Thereby, the workpiece sandwiched between the upper and lower molds is processed.

The current value of the servo motor 13 at this time is
It is limited according to the set bottom dead center of the actuator body 11, and the servo motor 13
Generates a certain pressurizing torque because it is about to rotate. The pressurizing torque can be appropriately changed according to the current value to be limited, that is, the set bottom dead center. After the set holding time has elapsed, the servo motor 13 is rotated in the reverse direction to raise the pressure ram 4 at a low speed to an acceleration position where the pressure torque is released, and then to a high speed to the standby position. In addition, when the actuator body 11 is moved up and down other than during pressurization, the entire torque of the servo motor 13 can be output.

According to the above control method, since the reciprocating movement from the standby position to immediately before the bottom dead center where the mold contacts the mold is high speed,
The operation time required for other than pressurization in one cycle can be shortened. As a result, operation efficiency is improved. In addition, by appropriately setting the set bottom dead center and the holding time of the actuator main body 11, it is possible to apply pressure with a minimum load. As a result, the load on the mold is reduced with less load loss, and the service life of the mold can be extended. Further, since the pressing ram 4 is moving down at a low speed when the dies are in contact with each other, the impact sound between the upper and lower dies 5, 6 is suppressed, and the dies 5, 6 are prevented from being damaged.

Next, the operational effects of the structure of the actuator 10 will be described. First, since the servomotor 13 capable of accurately controlling the number of rotations and the rotation angle is used as a drive source for raising and lowering the actuator body 11, the position and speed of the actuator body 11 can be controlled easily and with high precision. can do. Therefore, the workpiece can be processed at an appropriate speed.

Further, since the pressing ram 4 is disposed within a range where the outer peripheral edge of the cross section of the guide 16 is projected, the position where the reaction force generated at the time of pressing is eccentric to the pressing ram 4 is eccentric. However, the reaction force is directed into the outer peripheral edge of the guide 16, and the eccentric load is received by the guide 16.
Therefore, the actuator body 11 and the ball screw 1
8, or biased loading on other parts that receive the load,
The deformation accompanying this is suppressed, and the life of the device is prolonged. Further, the reaction force generated at the time of pressurization is determined by the thrust bearing 2
Since it is interrupted at 0 and does not transmit to the servo motor 13,
If the operation of the servo motor 13 is hindered or the drive shaft 13a
There is no danger of damages.

The above control is a preferred example in the case of plastic working requiring a pressurizing torque, and the actuator 10 of the present embodiment can be applied to, for example, cutting of a thin plate. In this case, there is no need to set the current value, that is, to perform the current control, but to set the bottom dead center slightly below the cutting level and actually lower the pressure ram 4 to the set bottom dead center; Speed control is performed.

[0026]

As described above, according to the present invention,
The pressure ram is reciprocated directly by a ball screw mechanism operated by a motor, and the pressure torque is appropriately controlled by the motor current value according to the set bottom dead center of the actuator body, so load loss is small. By reducing the load on the mold, it is possible to extend the service life of the mold, and to shorten the moving time of the actuator required in one cycle to improve the operation efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a press device to which an actuator according to an embodiment of the present invention is applied.

FIG. 2 is a partial cross-sectional side view of an actuator according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between a position of an actuator operated by a control method according to an embodiment of the present invention and time.

[Explanation of symbols]

 4 ... Pressure ram 10 ... Actuator 11 ... Actuator body 13 ... Servo motor (motor) 14 ... Servo amplifier (power supply, control means) 16 ... Guide 17 ... Ball screw mechanism 18 ... Ball screw 19 ... Ball screw nut 20 ... Thrust bearing (Reaction force receiving member)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4E088 AB04 BA01 BA10 EA05 EA06 4E089 EA01 EB01 EB02 ED02 FC01 FC03 4E090 AA01 AB01 BA02 CC04 HA01

Claims (5)

[Claims] An actuator for reciprocating a pressurizing ram of a press device, comprising: a ball screw mechanism in which a ball screw nut is screwed into a ball screw; By being integrally connected with the motor that can be set to
An actuator body reciprocally movable with the ball screw nut, the tip of which is attached with the pressurizing ram; a guide for guiding the reciprocating movement of the actuator body; a power supply for supplying electricity to the motor; Control means for controlling a value and a position of the actuator main body. 2. The actuator according to claim 1, wherein the motor is a servomotor. 3. The guide is a cylindrical body coaxially arranged around the actuator body, and the pressing ram is arranged within a range in which an outer peripheral edge of a cross section thereof is projected. 3. The actuator for a press device according to claim 1, wherein: 4. Between the motor and the ball screw,
2. A reaction force receiving member that receives all of the reaction force received from the pressure ram from the ball screw and blocks transmission of the reaction force to the motor is interposed.
4. The actuator for a press device according to any one of claims 1 to 3. 5. The method of controlling an actuator for a press device according to claim 1, wherein a set bottom dead center, which is a stroke end of the actuator body, exceeds an actual bottom dead center at which the mold hits the mold. Position, and sets the holding time of the pressurizing torque generated when the motor tries to rotate until reaching the current value corresponding to the set bottom dead center after reaching the actual bottom dead center. Immediately before the dead center, the deceleration position and the acceleration position are set, and the actuator body is moved at high speed from the standby position, which is the start / end position, to the deceleration position, and then moved forward at low speed to the actual bottom dead center. Then, the motor is driven so as to further move from the bottom dead center to the set bottom dead center to generate a constant pressurizing torque. Till low In moved backward, then the control method of the pressing device actuator for causing the backward at high speed to the standby position.