JPH0737484U - Slide drive device of press machine - Google Patents

Abstract

(57) [Abstract] [Purpose] Positioning of the slide and speed control are performed by the servo motor system, and pressure control of the hydraulic cylinder is performed by controlling the torque value of the servo motor within the allowable torque range of the servo motor. Precise position / speed control is possible by assisting the load of the part with a hydraulic cylinder. [Structure] The position of the slide (2) is changed to the linear scale (1
Position detection function to detect in 2) and servo motor (8)
The position and speed control function to detect the load torque of the servo motor (8) while controlling the positioning and speed of the slide (2) by the ball screw (11) whose drive source is the driving force of the press on the slide (2). In this case, the pressure control function is configured to control the pressure control valve while continuously detecting an increase / decrease in the torque value so as not to exceed the preset torque allowable value of the servo motor (8).

Description

[Detailed description of the device]

[0001]

INDUSTRIAL APPLICABILITY The present invention can be applied to a slide driving device of a hydraulic press machine.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open No. 2-262884 and Japanese Utility Model Application No. 1-135119 have been patented and applied as servo motor drive presses. There is. Also, in the case of rapidly approaching and returning the slide only with the hydraulic cylinder, a pump is used, a charge tank is installed above the hydraulic cylinder, and a pre-fill valve is used to supply the required flow rate. Supply and discharge are controlled only by the valve unit.

[0003]

When the conventional structure is applied, when the servomotor is driven, the power of the motor is restricted and a large pressing force cannot be generated. When controlling with a hydraulic cylinder, it is difficult to improve the accuracy of position control compared to a mechanical press machine driven by a servo motor due to the influence of response delay, valve switching time, and oil temperature change.

[0004]

[Means for Solving the Problems] In the present invention, the positioning and speed of the slide are controlled by the mechanical system of the servomotor, and the power required for press work is secured by the hydraulic cylinder.

[0005]

[Function] The slide is rapidly driven down and up by servo drive. When the slide is in the pressurizing area, when the slide descends, the prefill valve that was opened and supplying oil to the hydraulic cylinder is closed, and the hydraulic cylinder is pressure controlled. Positioning of the slide and speed control are performed by the servo motor system, and pressure control of the hydraulic cylinder is controlled so that the torque value of the servo motor is within the allowable torque range of the servo motor. The load torque of the servomotor is determined by observing the increase and decrease in the current value.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, a piston (4) of a hydraulic cylinder (3) attached to a frame (1) is fixed to a slide (2), and an adjustment nut (6) fixed to a bracket (5) of the slide (2). The servomotor (8) fixed to the bracket (7) of the frame (1) is connected by the ball screw (11) via the gears (9) and (10).

Under the basic condition that the servo motor (8) can sufficiently cover the acceleration / deceleration of the slide and the resistance, there is a possibility that the work load is applied to the slide (2) from the top dead center to the bottom dead center. During the process from the completion of the press work to the top dead center, the slide (2) is rapidly raised by driving the ball screw (11) with the servo motor (8) as the power source. At that time, the valve (15) and the relief valve (16) connected to the hydraulic cylinder (3) are closed, the solenoid valve B (17) and the prefill valve (13) are opened, and the tank (not shown) is shown. The oil in () is supplied to the hydraulic cylinder (3).

Immediately before the work load starts to be applied to the slide (2), the prefill valve (13) is closed while the slide (2) is driven by the ball screw (11) by the servo motor (8). Oil is supplied by a solenoid valve (17). At that time, if there is a delay in the supply, the valve (15) replenishes and supplies the oil, and if it is too fast, the relief valve (16) discharges the oil, and the precision of the slide (2) is reduced. Position control is possible.

FIG. 2 shows a control block diagram of the present invention. A position detection function for detecting the position of the slide (2) by the linear scale (12) and a position for detecting the load torque of the servo motor (8).・ When the work load of the press is applied to the speed control function and the slide (2), the increase or decrease of the torque value is continuously detected so as not to exceed the preset torque allowable value of the servo motor (8). It is composed of a pressure control function that controls the pressure control valve. The control of the pressure control valve is controlled by issuing a pressure command from the controller to the driver, detecting the actual pressure with the pressure head, and closing it.

[0010]

[Effect of the Invention] The hydraulic system is apt to suffer from response delay and disturbance due to temperature change, and is inferior to the mechanical system of the servomotor in position / speed control. Therefore, with the premise that the mechanical system of the servomotor can perform more precise control than the position / speed control using only hydraulic pressure, the pressurizing cylinder assists the pressing force that cannot be handled by the power of the servomotor. This allows precise position / speed control with a servo motor.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a slide driving device of a press machine according to the present invention.

FIG. 2 is a control block diagram of the present invention.

[Explanation of symbols]

1 is a frame, 2 is a slide, 3 is a hydraulic cylinder, 4 is a piston, 5 is a bracket, 6 is an adjusting nut, 7
Is a bracket, 8 is a servomotor, 9 and 10 are gears, 1
1 is a ball screw, 12 is a linear scale, 13 is a prefill valve, 14 is a solenoid valve A, 15 is a valve, 16 is a relief valve, and 17 is a solenoid valve B.

Claims (2)

[Scope of utility model registration request] 1. A slide drive device of a press machine, wherein a ball screw is used together with a servo motor for position / speed control in a hydraulic press machine in which a slide is driven by a hydraulic cylinder. 2. The servomotor control device for controlling the position and speed of a slide when a press is in a pressurized state according to claim 1, when the hydraulic cylinder control device exceeds a certain load within the allowable load range. The hydraulic cylinder control device controls the pressure oil supplied from the pump by the signal to control the pressure oil supplied from the pump so that the hydraulic cylinder pressurizes the servo motor within the allowable load range. When not in a state, the hydraulic cylinder control device opens a hydraulic chamber of the hydraulic cylinder and a flow path of an oil tank to allow passage of oil freely.