How Does Hydraulic Power Unit Work?

A hydraulic power unit (HPU) converts mechanical energy into hydraulic energy to power actuators (cylinders, motors). Here’s a step-by-step breakdown of its operation:

1. Power Generation
An electric motor or engine drives the hydraulic pump, which forces hydraulic oil from the reservoir (tank) into the system.
The pump creates flow and pressure, converting mechanical energy into hydraulic energy.

2. Fluid Delivery & Control
Pressurized oil flows through pipes/hoses to control valves (direction, pressure, or flow valves).
Directional valves determine the oil’s path—sending it to extend or retract a cylinder or rotate a hydraulic motor.
Pressure relief valves protect the system by limiting maximum pressure.

3. Actuation (Work Output)
High-pressure oil enters a hydraulic cylinder (linear motion) or hydraulic motor (rotary motion), moving the load.
The actuator’s movement depends on oil flow rate (speed) and pressure (force).

4. Return & Filtration
After performing work, the oil returns to the reservoir via a return line.
A filter cleans the oil before reuse, preventing contamination.

5. Cooling & Maintenance
Heat exchangers (air or liquid-cooled) regulate oil temperature.
The reservoir allows air bubbles to escape and contaminants to settle.