Sheet Metal · 2022年5月7日

How to solve the problem of high temperature and noise of servo hydraulic machine?

Conventional Hydraulic Press adopts asynchronous induction motor + common plunger pump or constant power plunger pump. The position, speed, direction and pressure of the hydraulic press are controlled by the control of hydraulic components. The pressure control adopts the overflow method, and the motor still works during standby. Due to the existence of the relief pressure, the energy loss is large. The model adopts ordinary plunger pump as the power source, and the speed control adopts throttling speed regulation, which results in serious energy loss and low transmission efficiency.

The model adopts constant power pump as the power source, and the speed control adopts volumetric speed control. Although the efficiency can be improved, the control range is small, and the constant power pump has a complex structure, high cost, and high failure rate.

The AC permanent magnet synchronous servo motor is applied to the hydraulic press to replace the ordinary induction asynchronous motor, and the servo driver and servo motor are reasonably configured according to the needs of the production process. The double closed-loop control of the pressure and flow of the AC servo system highlights the high efficiency, controllable and adjustable , The advantages of good reliability, the use of the servo motor can be frequently started, variable speed characteristics, to achieve servo control, thereby improving the performance of the hydraulic machine and reducing energy consumption, so that the hydraulic machine performance is improved, the standby load release is cancelled, and the energy consumption is greatly reduced. Not only can the main cylinder of the ordinary hydraulic press quickly descend and return, slow working stroke, pressure holding, fast return, and auxiliary cylinder upward and downward working modes, but also the main cylinder speed and pressure of the working stroke can be controlled in real time; pressure can be changed. Floating blank holder.

Servo hydraulic press and servo hydraulic press are energy-saving and high-efficiency hydraulic presses that use servo motors to drive the main drive oil pump, reduce control valve loops, and control the slider of the hydraulic press. Servo hydraulic presses are a new type of mechatronics product to save energy, low noise, and environment. Good, low maintenance costs, excellent controllability and stability, are favored and recognized by more and more enterprises. Especially under the premise that energy and environment are valued today, the application of servo hydraulic press to replace hydraulic and pneumatic press is the trend of future development.

Servo hydraulic press, servo hydraulic press are mainly composed of frame, machine head, worktable, servo motor, push rod, pressure plate and control switch. The machine head is cantilevered on the upper part of the frame, and the servo motor is installed vertically on the machine head. The lower end of the servo motor is coaxially connected to the push rod, and the pressure plate is installed at the lower end of the push rod. The ball screw is coaxially connected to the push rod, and a control switch is installed symmetrically on the outside of the workbench corresponding to the pressure plate, and the control switch is a linked two-hand start button.

Features of Servo Hydraulic Press

  • 1. Energy saving: The servo system adjusts the power output in real time according to the process requirements, and the power saving effect is 15%-70%;
  • 2. High efficiency: The servo system responds at a high speed, increasing the production efficiency by about 10%;
  • 3. Stability: The unique PQ decoupling control scheme and multi-stage PID control technology can effectively control the pressure overshoot and optimize the hydraulic equipment;
  • 4. Powerful function: special requirements for precision product manufacturing process;
  • 5. Improve the working environment: using internal gear pump, the noise is reduced by about 15dB compared with the plunger pump of the traditional equipment;
  • 6. ​​Lower oil temperature: As the reactive power leakage of the oil circuit system is greatly reduced, the hydraulic oil temperature is greatly reduced.

Multi-stage PID realization scheme

Servo hydraulic press has high requirements for the system speed response and oil pressure overpressure when the main cylinder is lowered. When the main cylinder is lowered, the speed of the oil pump needs to be stable and respond quickly to reduce the influence of system oil pressure changes on speed control. Large pressure overshoot will be generated when the main cylinder is slowly turned down to maintain the pressure. It is difficult to balance the control requirements of the two actions with a period of pressure proportional and integral gain. The servo drive has a multi-stage PID modulation mode (up to 7 stages). Two stages of pressure proportional and integral gain are usually used on hydraulic presses. A special stage of pressure proportional and gain is used for the slow down and pressure holding actions of the master cylinder. When switching PI parameters Trigger the PI controller to exit saturation, so that the overshoot of the holding pressure of the main cylinder is reduced when the main cylinder rotates slowly, and the process requirements are met. The main cylinder fast down and other actions share a period of pressure proportional and integral gain parameters to speed up the oil pump speed increase rate, while reducing the influence of system oil pressure changes on the oil pump speed, improving system stability.

Diversified communication modes

  • 1. Support RS485 communication and analog communication of various PLCs. Facilitate the transformation of old hydraulic press servo;
  • 2. Supporting special controller for hydraulic press for CAN communication to improve equipment performance and human-machine interface interoperability;
  • 3. It supports industrial bus communication, which greatly improves the transmission speed of equipment operation information, and facilitates the realization of multi-device networking and centralized networking control and remote control of intelligent automated production lines.

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