HYDRAULIC PUMP AND MOTOR CONTROL SYSTEMS
HYDRAULIC PUMP AND MOTOR CONTROL SYSTEMS
HYDRAULIC PUMP AND MOTOR CONTROL SYSTEMS
Hydraulic systems are one of the most important components that enable power transmission in industrial automation and mobile applications. Hydraulic pumps and motors, at the heart of these systems, convert fluid energy into mechanical energy, resulting in force and motion.
HYDRAULIC PUMP BASICS
Key Concepts:
Displacement (Vg): The volume of oil (cm³/lap) that the pump shaft presses in one turn.
Revolutions (n): The number of rotations of the pump shaft per minute.
Flow rate (qv): The amount of oil pumped by the pump in one minute (lt/min).
Pressure (p): The force created by the fluid against resistance (bar).
Note: Pumps do not create pressure; Pressure occurs as a result of the resistance encountered by the fluid in the system.
PUMP TYPES AND WORKING PRINCIPLES
GEAR PUMPS
They can operate at a pressure of up to 250 bar.
It is common in mobile and industrial systems.
It can be done in tandem (2–3–4).
VANE PUMPS
It can operate at pressures up to 210 bar.
They are known for their quiet operation.
It is preferred in mobile systems.
PISTON PUMPS
It has a compressive strength of up to 700 bar.
It is divided into threshold axis and threshold disc types.
It is used in industrial applications that require very high pressure.
Example Application: Variable displacement piston pumps with threshold axis principle can operate at a continuous pressure of 450 bar.
VARIABLE DISPLACEMENT PUMPS AND ENERGY EFFICIENCY
Variable displacement pumps save energy by automatically adjusting the flow rate according to the system requirement.
Regulation Types:
|
Regulation Type |
Definition |
Advantage |
|
DR (Pressure Regulation) |
The pump reduces the flow rate at a certain pressure. |
The system pressure is stabilized. |
|
FR (Flow Regulation) |
It adjusts the flow rate according to the pressure difference. |
The flow is kept constant. |
|
LR (Power Regulation) |
It provides constant power according to the formula Power = Flow x Pressure. |
Energy efficiency was maximum. |
Image: Energy saving graph (Constant flow pump vs. power regulated pump)
HYDRAULIC PUMP CONTROL SYSTEMS
Pumps and motors; controlled by hydraulic, electrical or mechanical impulses.
Major Control Types:
HD Control: Displacement control by hydraulic pilot pressure.
EP Control: Precise displacement control with electronic proportional valve.
HW Control: Simple control by manual servo valve.
LR+DR Combination: Combined use of pressure and power regulation.
Combined Controls: With HD + DR + LR systems, both energy savings and optimal performance are ensured.
CLOSED LOOP HYDRAULIC SYSTEMS
In closed-loop systems, the oil coming out of the pump returns to the pump after rotating the hydromotor.
Advantages:
Compact design
High pressure operation (450 bar)
Less oil volume required
Bidirectional mobility
Image: Closed-loop hydraulic system diagram
Control Types:
HD Control – Displacement control with external pilot warning
EP Control – Displacement adjustment with proportional valve control
EZ Control – Min-max displacement change with on-off valve
HW Control – Mechanical control with manual servo valve
HYDROMOTORS AND TORQUE CONTROL
Hydromotors convert fluid energy into mechanical rotational motion.
Basic Formulas:
Rev:( n = \frac{q_v \times 1000}{V_g} )
Torque:( T = 1.59 \times V_g \times \Delta p/ 100 )
Power:
(P=q_v\times\Delta p/600 )
Note: As the motor displacement increases, the torque increases, the rotational speed decreases.
Control Methods:
HA: Automatic control based on pressure increase
EP: External control with proportional valve
EZ: Min-max control with on-off valve
HD/HZ: Displacement control with hydraulic pilot actuation
Image: Graph showing the displacement-speed-torque relationship
Hydraulic pump and motor control systems are the cornerstone of modern hydraulic technology in terms of energy efficiency, precision, and durability.
Hidroman maximizes system performance and energy efficiency by offering integrated solutions with Bosch Rexroth technologies in industrial and mobile applications.