Servo Hydraulic Power Units in Angle Steel Processing Lines

Servo hydraulic power units and conventional hydraulic power units are two common power source devices in hydraulic systems, differing significantly in structure, working principle, performance characteristics, and application areas. The following analysis details these differences from multiple perspectives.

1. Working Principle and Control System

The core difference between servo hydraulic power units and conventional hydraulic power units lies in their control systems and drive methods.

- Conventional Hydraulic Power Units:

Conventional hydraulic power units typically use fixed displacement or variable displacement pumps as their power source, controlling hydraulic actuators (such as hydraulic cylinders or hydraulic motors) through components like solenoid directional valves, throttle valves, or proportional valves. Their control systems are relatively simple, primarily relying on mechanical or electro-hydraulic proportional control, resulting in slower response times and lower precision. Flow and pressure regulation in conventional hydraulic power units is usually done manually or mechanically, making high-precision dynamic control difficult.

- Servo Hydraulic Power Units:

Servo hydraulic power units, on the other hand, use servo motors to drive hydraulic pumps, combined with high-precision sensors and closed-loop control systems, to achieve precise control of the hydraulic system. The core of a servo hydraulic power unit lies in its closed-loop feedback mechanism. By monitoring parameters such as pressure, flow, and position of the hydraulic system in real time, it automatically adjusts the speed and torque of the servo motor, thereby achieving high-precision dynamic response and position control. The control system of a servo hydraulic power unit typically employs advanced digital control technologies, such as PID control, fuzzy control, or adaptive control, to meet the high-precision requirements under complex working conditions.

2. Energy Efficiency and Energy Saving Performance

Servo hydraulic power units have significant advantages in energy efficiency.

- Conventional Hydraulic Power Units:

Conventional hydraulic power units have lower energy efficiency, mainly because when using fixed displacement or variable displacement pumps, the pump still operates at a constant speed even under light or no load, resulting in a significant amount of energy loss as heat. Furthermore, the relief valve in conventional hydraulic power units returns excess oil directly to the tank when the system pressure exceeds the set value, further wasting energy.

- Servo Hydraulic Power Units:

Servo hydraulic power units drive the hydraulic pump through a servo motor, which can adjust the pump speed and output flow in real time according to load requirements, thereby significantly reducing energy loss. In low-load or standby states, servo motors can reduce speed or even stop operating, minimizing unnecessary energy consumption. Furthermore, the closed-loop control system of a servo hydraulic power unit can precisely match system requirements, avoiding overflow losses and resulting in significant overall energy savings.

3. Dynamic Response and Control Accuracy

Servo hydraulic power units have significant advantages in dynamic response and control accuracy.

- Conventional Hydraulic Power Units:

Conventional hydraulic power units have slower dynamic response and lower control accuracy. Because their control systems are mostly open-loop or semi-closed-loop, they cannot precisely adjust hydraulic parameters in real time. Therefore, in applications requiring high-precision positioning or rapid response, conventional hydraulic power units often fall short.

- Servo Hydraulic Power Units:

The closed-loop control system of a servo hydraulic power unit can achieve millisecond-level dynamic response, while maintaining control accuracy down to the micrometer level or even higher. Servo hydraulic power units are widely used in applications requiring high-precision position, speed, and force control, such as CNC machine tools, injection molding machines, and robotics.

4. System Complexity and Cost

Servo hydraulic power units have higher system complexity and cost, but their performance advantages are significant.

- **Standard Hydraulic Power Unit:**

Standard hydraulic power units have a relatively simple structure, low manufacturing cost, and are easy to maintain. Due to their basic control system, they are suitable for applications where high precision and response speed requirements are not high, such as general machine tools and construction machinery.

- **Servo Hydraulic Power Unit:**

Servo hydraulic power units have a complex structure, involving high-precision sensors, servo motors, and advanced control algorithms, resulting in higher manufacturing costs. Furthermore, the maintenance and debugging of servo hydraulic power units require a higher level of technical expertise. However, their high precision, high response speed, and energy-saving performance give them an irreplaceable advantage in high-end manufacturing fields.

5. Application Areas

The application areas of servo hydraulic power units and ordinary hydraulic power units differ significantly.

- **Standard Hydraulic Power Unit:**

Standard hydraulic power units are widely used in applications where high precision and response speed requirements are not high, such as agricultural machinery, construction machinery, and general machine tools. These fields have relatively low performance requirements for hydraulic systems, and ordinary hydraulic power units are sufficient to meet their needs.

- Servo Hydraulic Power Units:

Servo hydraulic power units are primarily used in high-precision, high-dynamic-response applications, such as CNC machine tools, injection molding machines, precision stamping equipment, aerospace equipment, and robotics. These fields have high requirements for the control accuracy, response speed, and energy efficiency of hydraulic systems, and servo hydraulic power units offer superior solutions.

6. Noise and Environmental Performance

Servo hydraulic power units excel in noise control and environmental performance.

- Conventional Hydraulic Power Units:

Conventional hydraulic power units, due to their use of constant-speed motors and hydraulic pumps, generate significant noise during operation, especially under high-pressure and high-flow conditions. Furthermore, conventional hydraulic power units have lower energy efficiency, resulting in more energy loss as heat, increasing the system's heat dissipation burden.

- Servo Hydraulic Power Units:

Servo hydraulic power units, through the stepless speed regulation of servo motors, can adjust the speed according to load requirements, significantly reducing operating noise. In addition, the high energy efficiency of servo hydraulic power units reduces energy loss and heat generation, helping to lower system temperature rise and improve environmental performance.

7. Maintenance and Lifespan

Servo hydraulic power units require higher maintenance standards, but their lifespan and reliability are generally superior to those of conventional hydraulic power units.

- Conventional Hydraulic Power Units:

Conventional hydraulic power units have a simple structure and are easy to maintain, but due to their lower control system precision, hydraulic components may experience greater impact and wear during operation, resulting in a shorter lifespan.

- Servo Hydraulic Power Units:

The high-precision control system of servo hydraulic power units can reduce impact and wear on hydraulic components, thereby extending system lifespan. However, the maintenance of servo hydraulic power units requires a higher level of technical expertise, especially in the debugging and calibration of sensors and control systems.

Summary

Servo hydraulic power units and conventional hydraulic power units differ significantly in their working principles, energy efficiency, control precision, dynamic response, and application areas. Servo hydraulic power units occupy an important position in high-end manufacturing fields due to their high precision, high response speed, and energy-saving performance, while conventional hydraulic power units are widely used in applications with lower performance requirements due to their low cost, simple structure, and ease of maintenance. The choice of which type of hydraulic power unit to use should be based on a comprehensive consideration of specific application needs, budget, and technical capabilities.