The self-aligning roller bearings used in fans play a crucial role in the operation of fans. Their core function is to adapt to the complex stress requirements of fans under complex working conditions through unique structural design, ensuring efficient, stable, and long-lasting operation of fans. The following is a detailed explanation of its specific functions and technical advantages:
1. Core function
Carrying multi-directional composite loads
When a fan (especially a large industrial fan or centrifugal fan) is in operation, the bearing needs to simultaneously withstand radial forces (such as centrifugal forces generated by impeller rotation and airflow impact) and axial forces (such as thrust generated by impeller asymmetry or installation deviation). Self aligning roller bearings are designed with double row rollers, which can simultaneously share radial and axial loads, avoiding damage to single row bearings due to overload.
Automatic compensation for installation errors and operating deviations
During the installation or operation of the fan, the axis and bearing seat centerline may be offset (i.e. "centering error") due to factors such as foundation settlement, thermal expansion, and vibration.
. The spherical raceway design of self-aligning roller bearings (outer raceway is spherical, inner raceway is cylindrical) allows the rollers to automatically adjust the angle when offset, maintaining the contact state between the rollers and the raceway, avoiding edge stress concentration, and reducing wear and vibration.Reduce vibration and noise
Fan vibration is one of the main reasons for bearing damage and shortened equipment life.
. Spherical roller bearings reduce sliding friction between rollers and raceways by optimizing roller shape (such as logarithmic convexity design) and cage structure, lowering vibration frequency and amplitude, while suppressing noise generation, and improving the smoothness of fan operation.Adapt to high-speed and heavy-duty working conditions
Large fan impellers have large diameters and high speeds (some centrifugal fans can reach thousands of revolutions per minute), and require long-term continuous operation.
. Spherical roller bearings are made of high-strength materials (such as high carbon chromium bearing steel) and precision machining processes, which can withstand the centrifugal force generated by high-speed rotation. At the same time, optimized lubrication design (such as oil grooves and oil holes) ensures sufficient lubrication and extends the bearing life.2. Technical advantages
Strong centering performance
The centering angle can usually reach 1.5 °~3 °, which is much higher than that of ordinary cylindrical roller bearings (generally without centering ability), and can compensate for a larger range of installation errors and operating deviations, reducing the requirements for wind turbine installation accuracy.
.Long service life and high reliability
Rolling fatigue life: The contact area between the roller and the raceway of the self-aligning roller bearing is large, and the stress distribution is uniform, which can significantly improve the rolling fatigue life (by 30%~50% compared to ordinary bearings).
.Impact resistance: The double row roller structure can disperse the impact load, avoid single point overload, and is suitable for working conditions where the fan frequently starts and stops or experiences load fluctuations.
.Low maintenance cost
Long lubrication cycle: Some self-aligning roller bearings adopt a sealed design (such as with dust covers or rubber seals), which can reduce grease leakage and external impurities intrusion, extend lubrication cycle, and reduce maintenance frequency.
.Easy to replace: Self aligning roller bearings are standard parts that do not require special tools for replacement and can be quickly disassembled, reducing downtime.
.III. Typical Application Scenarios
Large industrial fans
Centrifugal fans: used in boiler ventilation, flue gas emissions and other scenarios, they need to withstand high temperature, high speed, and heavy load conditions.
. Axial flow fan: used for factory ventilation and air conditioning systems, requiring low noise and long lifespan operation. Energy fieldWind turbine generator: The main shaft bearing needs to withstand huge wind loads and impeller rotational torque, and the self-aligning roller bearing can compensate for the bending deformation of the main shaft caused by wind loads.
.Gas turbine fan: It needs to operate stably in high temperature and high-speed environments, and the high temperature resistance and centering ability of self-aligning roller bearings are crucial.
.Environmental protection equipment
Dust removal fan: used in flue gas purification systems, it needs to withstand the impact and corrosion of dusty airflow. The sealing design of self-aligning roller bearings can prevent dust from entering.
.Exhaust gas treatment fan: requires long-term continuous operation, and the high reliability of self-aligning roller bearings can reduce downtime caused by malfunctions.
.IV. Selection and Maintenance Suggestions
Selection Points
Load Calculation: Calculate radial and axial forces based on parameters such as fan impeller weight, speed, and airflow pressure, and select bearings with rated loads higher than the calculated values.
.Alignment angle: Select the bearing with the appropriate alignment angle (generally recommended ≥ 1.5 °) based on the installation accuracy and operating offset of the fan.
.Sealing form: Select the sealing type (such as open, dust cover, rubber seal) according to the working environment (such as dust, humidity, high temperature).
.Maintenance points
Regular lubrication: Regularly replenish or replace lubricating grease according to the equipment manual requirements to avoid overheating or wear caused by insufficient lubrication.
.Temperature monitoring: Install temperature sensors to monitor the bearing operating temperature in real time. If there is any abnormal temperature rise (such as exceeding 80 ℃), stop the machine immediately for inspection.
.Vibration analysis: Analyze the operating status of bearings through vibration monitoring instruments to detect early signs of faults (such as abnormal frequency and increased amplitude).
.Alignment check: Regularly check the alignment of the fan shaft and bearing seat to avoid bearing misalignment caused by alignment errors.
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