What are CB series gear pumps and what are their structural features?
CB series gear pumps are external gear pumps widely used in basic hydraulic systems.
They are valued for simple structure, low cost, and stable flow, making them ideal for low-pressure applications.
CB gear pumps typically feature:
Plain bearings (sliding bearings)
Fixed displacement design
Larger internal clearances
No axial or radial pressure compensation
These characteristics directly influence their pressure capability.
Why CB Series Gear Pumps Are Limited to Low-Pressure Systems
1. Reason #1: Limited Bearing Load Capacity
CB pumps usually use sliding bearings, which have limited load-bearing capacity.
At high pressure, radial forces on the gear shafts increase significantly, accelerating bearing wear and leading to early failure.
2. Reason #2: Lack of Pressure Compensation
CB gear pumps do not include axial or radial compensation mechanisms.
As pressure rises, internal clearances cannot be automatically adjusted, resulting in rapid efficiency loss and wear.
3. Reason #3: Large Internal Leakage at High Pressure
Higher system pressure increases internal leakage through:
Gear side clearances
Gear tooth meshing gaps
This causes:
Reduced volumetric efficiency
Increased heat generation
Unstable system performance
4. Reason #4: Housing Strength Limitations
The pump housing of CB series pumps is designed for low to medium pressure levels.
Operating beyond rated pressure may cause:
Deformation of the pump body
Increased noise and vibration
Risk of structural damage
Typical Applications of CB Gear Pumps
CB series gear pumps are commonly used in:
Agricultural machinery
Small hydraulic power units
Low-pressure lifting systems
Simple industrial equipment
Recommended working pressure: typically ≤ 16 MPa (depending on model).