When installing self-aligning roller bearings, how can one check if the installation is correct?

After installing the self-aligning roller bearings, it is necessary to confirm whether they are in the correct position through multi-dimensional inspection to avoid abnormal equipment operation due to installation deviations. The following is a standardized inspection process from three aspects: appearance inspection, precision measurement, and operation testing, along with specific tools and judgment criteria:
1. Appearance and mating surface inspection (basic inspection)
1. Axial fit check
Detection tools: feeler gauge, right angle ruler
Operation steps:
Observe whether the inner ring of the bearing is fully in contact with the shoulder of the shaft, and there is no obvious gap.
Insert the feeler gauge into the mating surface gap:
Interference fit: Gap ≤ 0.03mm (the 0.03mm piece of the feeler gauge should not be able to be inserted);
Clearance fit: The gap between the outer ring and the seat hole retaining shoulder is allowed to be ≤ 0.05mm (but ensure reliable axial fixation).
Abnormal handling: If the gap exceeds the limit, check the perpendicularity of the shaft shoulder / retaining shoulder (use the right angle ruler to fit the shaft shoulder, the gap > 0.02mm requires grinding repair) or the mating surface size tolerance.
2. Installation direction and positioning mark confirmation
Direction check:
If the self-aligning roller bearing has a sealing ring (such as 22208E/C3W33), the sealing ring should face the lubrication side, and the dust cover should face outward;
When multiple bearings are installed in series, mark the bearings according to the drawing (the fixed end and the moving end should not be installed in reverse).
Positioning mark: If there is a positioning line marked on the shaft neck and the bearing inner ring before installation, the marking after installation should be aligned (deviation ≤ 0.5mm), ensuring accurate circumferential positioning.
2. Precision and clearance measurement (core inspection)
1. Radial runout detection
Detection tools: dial indicator, magnetic indicator stand
Operation steps:
Fix the shaft, and the dial indicator probe should be perpendicular to the outer surface of the outer ring (10-15mm from the edge);
Slowly rotate the shaft one turn, and record the maximum fluctuation value of the dial indicator:
Normal precision bearing (G grade): Radial runout ≤ 0.05mm;
Precision bearing (P5 grade): ≤ 0.02mm.
Abnormal cause: Runout exceeds the limit may be due to poor roundness of the shaft neck (> 0.01mm), or installation skew (axiality > 0.05mm/m), which requires reinstallation or regrinding of the shaft neck.
2. Axial clearance detection
Detection tools: dial indicator, thrust block
Operation steps:
Fix one side of the bearing (such as the inner ring) on the shaft, and the dial indicator probe should be against the shaft end or the outer ring end face;
Push the shaft or the outer ring along the axial direction with a thrust block, and read the maximum difference (axial clearance):
For the 22320 self-aligning roller bearing (inner diameter 100mm), the C3 group clearance standard is 0.100-0.150mm;
The clearance must comply with the GB/T 4604.1 standard corresponding to the bearing model, and if the deviation exceeds ±10%, adjustment is required.
Adjustment method:
Too small clearance: Check if the interference amount is too large (the heating temperature can be appropriately reduced, such as from 100℃ to 80℃);
Too large clearance: For clearance fit, you can increase the thickness of the outer ring retaining ring pad (for a target clearance of 0.12mm, the measured value is 0.15mm, add 0.03mm pad).
3. Parallelism and perpendicularity detection
Parallelism:
Use a laser centering instrument to detect the parallelism between the shaft and the seat hole, the deviation of the long shaft (> 500mm) is ≤ 0.05mm/m, the short shaft ≤ 0.03mm/m, if the deviation exceeds the limit, adjust the seat hole position or replace the bearing seat.
Perpendicularity:
Measure the perpendicularity of the shaft shoulder to the axis with a perpendicularity detector, the tolerance is ≤ 0.02mm (within 100mm length), otherwise, grind the shaft shoulder end face.
3. Operating condition and temperature rise test (dynamic inspection)
1. No-load trial operation detection
Detection items:
Speed and time: Run at low speed (300r/min) for 10 minutes, without abnormality, then increase to the rated speed (such as 1500r/min) for 30 minutes; Noise Monitoring: Measure the noise level using a sound level meter at a distance of 100mm from the bearing housing. The noise value should be ≤ 65 dB(A). If there is a "clicking" abnormal sound, it may be due to the collision of rollers or installation skew, and the machine needs to be shut down for inspection.
2. Temperature Rise and Vibration Detection
Temperature Rise Measurement:
Use an infrared thermometer to measure the temperature of the outer ring of the bearing. When the ambient temperature is 25℃, the temperature rise should be ≤ 30℃ (i.e., the outer ring temperature should be ≤ 55℃). If it exceeds 40℃, the machine needs to be shut down immediately. Possible reasons:
Excessive lubricating grease (more than 1/2 of the cavity);
Excessive interference fit causing friction and heat generation.
Vibration Detection:
Use a vibration analyzer to measure the radial vibration velocity. At the rated speed:
Ordinary equipment: ≤ 2.5mm/s;
Precision equipment: ≤ 1.8mm/s.
If the vibration frequency is a multiple of the rolling body passing frequency (BPFI/BPFO), it may be due to eccentric installation or bearing damage.