Understanding Mechanical Loss in Hydraulic Pumps

1. What Is Mechanical Loss?

Mechanical loss is the loss of input power caused by friction and mechanical resistance between internal pump components.

It represents the difference between:Mechanical input power, and Useful hydraulic power delivered

Higher mechanical loss = Lower overall pump efficiency.

2. Main Causes of Mechanical Loss

①Friction Between Moving Components：

Friction occurs in:

Gears & bushings

Pistons & cylinder bores

Vanes & cam rings

These resist motion and consume additional power.

Smooth surfaces & precision machining minimize this loss.

②Bearing & Shaft Resistance

Mechanical resistance increases due to:

Bearing friction

Shaft misalignment

Unbalanced loads.

This leads to higher torque requirements and reduced mechanical efficiency.

③Lubrication & Oil Effects

Mechanical losses increase when:

Lubrication is insufficient

Oil viscosity is too high

Oil film cannot form properly

Result: higher drag, more heat, faster wear.

3. Why It Matters

High mechanical loss causes:Increased energy consumption,Excessive heat generation,Reduced pump lifespan,Lower hydraulic performance.

Optimizing lubrication, alignment, and component quality significantly reduces mechanical loss.