What issues should be considered during the installation and maintenance of sliding bearing housings?

The installation and maintenance of sliding bearing housings is the key to ensure stable operation of the equipment and prolong its service life. It requires systematic control from four aspects: installation accuracy, lubrication management, operation monitoring and regular maintenance. Specific technical points and caveats are as follows:

1.Foundation Treatment and Calibration
Foundation Requirements: Installation surface must be flat and rigid with a a flatness error ≤ 0.05mm/m to prevent bearing housing from tilting due to foundation deformation.
A second a secondary grouting layer ≥ 50mm thickness) must be reserved for preburied anchor bolts. High-strength grout (such as epoxy resin) should be used to fill gaps to eliminate vibration transmission errors.
Case study: due to uneven foundation, the bearing of rolling mill has a deviation of 0.3mm. After running, the bearing temperature rose to 85°C and the Babbitt alloy layer melts.
Alignment Accuracy: use laser alignment instrument or dial indicator to check the the coaxiality of bearing housing and drive shaft. The heat exchanger error must be limited to 0.05mm.
For multi-bearing housing systems,such as gearboxes, the position of all bearing housing must be synchronized to avoid stress concentration due to shaft bending.
Data show that for every 0.1mm increase in shaft alignment deviation, bearing life may be shortened by more than 50%.
2.Clearance Control and Cleaning
Radial clearance: Measurement of clearance between bearing and shaft neck using a feeler gauge or lead hammer method. clearance value shall conform to the design requirements (usually 0.15-0.25% of the shaft diameter).
Insufficient clearance will lead to oil film rupture, resulting in dry abrasion; too much clearance, will reduce support stiffness, causing vibration.
Adjustment Method: Adjusting gasket (thickness accuracy ±0.01mm) between bearing housing and base is added or removed.
Cleaning requirements: Before installation, clean bearing housing holes, shafts and mating surfaces with anhydrous ethanol to remove oil, metal shavings and other impurities.
Wear clean gloves when assembling and avoid direct contact between your fingers and friction surfaces such as the Babbitt metal layer to prevent sweat corrosion.
Case study: A turbine bearing housing developed scratches after running due to uncleanliness during assembly, with hard particles embedded in the Babbitt alloy layer.

1.Lubricant Selection
Type Matching:
High speed, light load (e.g., fans): low-viscosity lubricants (e.g., ISO VG32) is used to reduce friction loss.
Heavy load, low speed (e.g., rolling mills): use of high-viscosity lubricants (e.g., ISO VG460) or semi-solid lubricating oil (e.g., lithium-based grease) to form a stable oil film.
Corrosive environments (e.g., chemical pumps): use of synthetic lubricants (e.g. polyether-based) or grease containing antiseptic additives.
Viscosity verification: The viscosity of a lubricant at working temperature is confirmed using a viscosity-temperature curve (usually maintained at 20-100 cSt).
Case study: In high-temperature bearings (operating temperature 150°C), viscosity dropped below 5 ° C when using ISO VG32 lubricant, resulting in rupture of oil film.
2. Optimization of Lubrication Method Optimization
Oil Lubrication System: Forced lubrication (e.g., oil pump circulation) requires stable oil pressure (0.1-0.3 MPa) to prevent lubrication interruptions due to pressure fluctuations.
Thin oil lubrication requires an oil level alarm device, which can be automatically turned off if the oil level is too low.
Case study: lubrication of a gearbox was interrupted by an oil pump malfunction, causing the bearing temperature to rise to 200°C in 10 minutes and the Babbitt alloy layer to melt.
Grease Lubrication System: Regularly replenish grease (usually 3-6 months) to prevent grease aging and lubrication failure.
The replenishment amount should be controlled at 1/3-1/2 of the bearing cavity volume, and excessive replenishment can lead to excessive temperature.
Case study: After operation, motor bearing become oily and carbonize as temperature rises by 80°C due to excessive grease filling (which occupies 80% of the cavity).

1. Vibration and Temperature Monitoring
Vibration Analysis: The vibration spectrum of bearing housing is detected by vibration sensor with emphasis on first harmonic (axial movement) and second harmonic (oil film eddy).
Gaps, alignment or lubrication issues lubrication issues be investigated when residual values of vibration exceed the standard (e.g., the "undesirable" areas in ISO 10816-3).
Case study: The bearing bearing housing vibration the gearbox of the wind turbine gearbox vibrates too much (effective value greater than 8 mm/s). ring raceway of bearing was found to be peeling when removing.
Temperature Monitoring: PT100 temperature sensors are installed on the outer surface of bearing housing to monitor bearing temperature in real time (normal value ≤ 70°C).
Downtime checks are required when temperatures are abnormally high (> 10°C/h). Possible causes include lubrication interruption, gaps or sudden load changes.
2. Load and speed control
Overload Protection: torque limiter or overload clutch in transmission system to prevent damage to bearing housing due to instantaneous overload (e.g., jamming stopping).
Case study: due to material blockage, the torque of conveyor belt bearing housing exceeded the limit (3 times the rated value), causing the bearing inner ring to break.
Servo bonding: Avoid operating equipment near critical speed (e.g., the first natural frequency of the shaft system) to prevent resonance and bearing housing from loosening.
The foundation bolts of the turbine bearing is loose due to near critical speed (±10%).

1. Maintenance Cycle setting
Daily Inspection: check oil level, temperature, leakage and record operation data daily.
Clean oil stains on bearing housing surface weekly to prevent dust accumulation from affecting heat dissipation.
Regular Overhaul: Remove and inspect bearing housings every 3-6 months to check for wear and tear on the Bobbitt metal layer, seals and mating surfaces.
Change the oil or grease every 1-2 years to clean the oil system.
Case study: Cement grinding bearing housing due to failure to replace lubricant regularly (2 years without replacement of lubricant), bearing wear and tear.
2.Disassembly and Repair Process
Disassembly Sequence: first remove transmission components (such as coupling and pulley), then loosen bearing housing fastening bolts to avoid deformation due to hammering.
During assembly, tighten the bolts diagonally to ensure that torque value are in line with design requirements (e.g. M16 bolts with torque of 200 bovine meters).
Repair method: When the Babbitt alloy layer wears more than0.5 mm, recasting is required. Before recasting, preheat the bearing housing to 150-200°C to reduce stress.
All seals (such as O-rings) must be replaced to prevent leakage due to reuse.
Case study: A compressor bearing housing leaked lubricant after a month of operation due to repeated use of old seals.