What are the factors that affect the insufficient pressure in the Hydraulic Power Unit?

A Hydraulic Power Unit (HPU) is a vital hydraulic system component designed to perform a variety of specific tasks in industrial and mobile applications. The core structure of a Hydraulic Power Unit typically consists of a hydraulic pump, an electric motor, and an oil reservoir (tank). These elements form the foundation of the system and play a crucial role in its performance.

Additionally, HPUs are equipped with directional control valves to manage flow direction, as well as throttle valves that regulate flow rate by adjusting the throttling cross-section or length. Throttle valves are known for their simple structure and low manufacturing and maintenance costs, though they may have limitations such as poor sealing performance. Despite this, throttle valves do not significantly affect the overall performance of the hydraulic system.

Hydraulic Power Units also incorporate essential hydraulic control components such as relief valves and pressure control valves, enabling the system to function efficiently under varying load conditions. Together, these components ensure that the HPU delivers consistent, reliable power for hydraulic machinery.

Common Reasons for Insufficient Pressure in Hydraulic Power Units

Over time, it's common for hydraulic systems to experience pressure loss or insufficient pressure. Below are several key reasons for this issue:

1. Internal Leakage in Hydraulic Pumps or Actuators
   Hydraulic pumps—such as fixed displacement vane pumps, variable displacement vane pumps, variable piston pumps, internal gear pumps, and external gear pumps—can suffer from excessive internal leakage. Damage to hydraulic cylinders or motors may also contribute to pressure drop.

   
   

2. Improper Design of Integrated Manifold Blocks
   Poorly designed manifold blocks or channel blocks can restrict flow or lead to inefficient pressure distribution. This typically results from the inexperience or lack of expertise of the hydraulic system designer.

   
   

3. Low Rotational Speed of Hydraulic Pumps
   If the hydraulic pump operates at speeds below its specified range, it may fail to generate adequate flow and pressure. This applies to various pump types, including vane, piston, and gear pumps.

   
   

4. Relief Valve Malfunction
   A damaged or incorrectly set relief valve may allow hydraulic oil to bypass the system and return directly to the tank, causing a drop in system pressure. In such cases, the valve should be repaired or replaced.

   
   

5. Low Hydraulic Oil Level
   An insufficient oil level in the hydraulic reservoir can lead to cavitation and pressure instability. It is essential to maintain the oil level as indicated on the oil level gauge to ensure proper operation.