CAT 549-4321 Roller Bearing

CAT 549-4321 is a Caterpillar single-row imperial tapered roller bearing (inner ring + outer ring + rollers + cage assembly), suitable for heavy-duty components such as the Cat 320D2/330D2 excavator swing gearbox, the 966M loader drive axle, and the C15 engine flywheel end. It can withstand both radial and unidirectional axial loads simultaneously, ensuring stable operation of the transmission system (Cat® Parts). The following is structured technical and application information:

Core Technical Parameters
Item Details
Basic Attributes
Model 549-4321, Single-row tapered roller bearing (imperial, inner ring + outer ring + roller + cage assembly), suitable for Cat 320D2/330D2 excavator swing gearbox, 966M loader drive axle, C15 engine flywheel end, material is 52100 chromium bearing steel (outer ring carburized and quenched HRC 60-64, inner ring quenched HRC 58-62), cage is stamped carbon steel, operating temperature -40℃ to +120℃, single weight approximately 4.2 kg, used to bear radial and unidirectional axial loads, suitable for heavy load and vibration conditions, prevents shaft movement and abnormal wear, and ensures stable operation of transmission components.

Key Dimensions
Inner diameter 63.50 mm (2.5 inches, tolerance 0.0000/+0.0010 inches), outer diameter… 146.05 mm (5.75 inches), total width 41.275 mm, inner ring width 38.10 mm, outer ring width 26.988 mm, minimum chamfer on inner ring 3.0 mm, minimum chamfer on outer ring 2.8 mm, bore and shaft fit tolerance k6 (+0.018/+0.001 mm), end face runout ≤0.02 mm

Load and Speed: Basic dynamic load rating Cr=185 kN, basic static load rating C0r=220 kN, grease lubrication limiting speed 2400 r/min, oil lubrication limiting speed 3200 r/min, suitable for heavy-duty, low-to-medium speed conditions

Compatible Models: Cat 320D2/330D2 excavators (slewing gearbox), 966M loaders (drive axle), C15 engine (flywheel end), 140M2 graders (rear axle differential)

Assembly Fit: Compatible Shaft diameter 63.5 mm (tolerance k6, +0.018/+0.001 mm), bearing housing bore diameter 146.05 mm (tolerance H7, +0.035/0 mm). During installation, axial clearance needs to be adjusted to 0.04-0.08 mm. An interference fit (inner ring interference with shaft 0.008-0.018 mm) and a clearance fit (outer ring clearance 0.008-0.020 mm) should be used.

Installation and Maintenance Points: Before installation, clean the bearing, journal, and bearing housing bore. Check for scratches, rust, and cracks on the surfaces. Measure the dimensions of the journal and bearing housing bore to ensure the fit meets requirements. The journal fillet radius should be ≤3.0 mm to avoid stress concentration.

Install the bearing using a heat-fitting method (heating the inner ring to 80-100℃) or a press-fitting method, ensuring the bearing inner ring is coaxial with the journal. Do not strike the bearing directly with a hammer to prevent deformation or damage to the rollers. After installation, adjust the axial clearance to 0.04-0.08 mm to ensure normal bearing operation.

Maintenance Recommendations: Check the bearing temperature, vibration, and lubrication condition every 2000 hours. If the temperature exceeds 80℃, vibration is abnormal, or the grease is deteriorated, address the issue promptly. Replace the grease (Cat Moly Grease recommended) every 5000 hours. If the bearing exhibits abnormal noise, jamming, or wear exceeding 0.10 mm, replace it immediately to prevent shaft damage.