Rotation Axis Design
The design focus is to minimize eccentricity around the rotation axis.
Avoid Double Centering
Multiple centering through form-fit at the bearing bore should be avoided, as this can deform the bearing and increase friction.
Bearing Preload
After complete assembly and bolting, the bearing is preloaded and clearance-free in both radial and axial directions. Preload is a key factor for achieving specified stiffness, but it also generates friction torque.
- Bearings are factory-set with appropriate preload
- After complete assembly, bearings are radially and axially clearance-free
- Preload values affect stiffness and friction torque
Temperature Management
Temperature differences between shaft and housing significantly affect radial preload. Proper temperature management is critical for bearing performance.
Effects of Higher Shaft Temperature
- Increased friction and surface pressure
- Reduced bearing service life
- Possible overheating failure
Effects of Higher Housing Temperature
- Reduced preload and stiffness
- May cause increased bearing clearance
- Affects positioning accuracy
Recommendation
An efficient cooling system is recommended to minimize temperature fluctuations. Independent controllable cooling for inner and outer rings is often helpful. For high-speed, long duty cycle applications, temperature monitoring through sensor bores is recommended.
Cooling Design
To achieve limiting speed and long duty cycles, oil circulation cooling on both inner and outer rings is recommended.
Inner Ring Rotating Cooling
For NGS bearings with inner ring rotation, the following cooling configurations are recommended:
Outer Ring Rotating Cooling
For NGS-SBI bearings with outer ring rotation, the following cooling configuration is recommended:
Cooling Design Key Points
- Inner and outer rings should have independent controllable cooling systems
- Coolant flow rate should be calculated based on thermal load
- Avoid coolant leakage into the bearing interior
- Cooling channel design should ensure uniform heat transfer
Unbalance / Eccentric Load
Eccentric components generate high additional forces on the bearing and may cause vibrations in high-speed applications.
Effects
- Additional dynamic loads during high-speed operation
- May cause vibration and noise
- Affects machining accuracy and surface quality
- Accelerates bearing wear
Recommended Measures
- Use automatic unbalance correction systems
- Set residual unbalance limits
- Regular inspection and unbalance correction
- Avoid installing components with large eccentric mass
Important Note
High acceleration and strong braking processes may introduce additional friction into the system through inertia moments. Special attention to unbalance control is required in high-speed applications.
Related Sections
- Surrounding Structure Design - Detailed design requirements and tolerances
- Shaft Fit Recommendations - Shaft fit tolerance selection
- Housing Fit Recommendations - Housing fit tolerance selection
- Bearing Commissioning - Break-in and verification procedures