Description
CAT 3K-3403 38.1mm Roller Bearing
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The CAT 3K-3403 is a Caterpillar single-row imperial tapered roller bearing (complete assembly: inner ring + outer ring + rollers + cage), suitable for Cat 320D/330C excavator swing gearboxes, 966H loader drive axles and C9 engine camshaft ends. It is used to withstand radial and unidirectional axial loads, suitable for heavy-duty, low-to-medium speed conditions, prevent shaft runout and abnormal wear, and ensure stable operation of the transmission system (Cat® Parts). The following is structured technical and application information:
Core Technical Parameters
Item Details
Basic Attributes
Model 3K-3403, Single Row Tapered Roller Bearing (Imperial, Complete Assembly), Suitable for Cat 320D/330C Excavator Swing Gearbox, 966H Loader Drive Axle, C9 Engine Camshaft End, Material: 52100 Chromium Bearing Steel (Outer Ring Carburized and Quenched HRC 60-64, Inner Ring Quenched HRC 58-62), Cage: Stamped Carbon Steel, Operating Temperature: -40℃ to +120℃, Single Weight: Approximately 2.8 kg, Used to withstand radial and unidirectional axial loads, Suitable for heavy-duty, low-to-medium speed conditions, Prevents shaft movement and abnormal wear, Ensures stable operation of transmission components (Cat® Parts)
Key Dimensions
Inner Diameter: 50.80 mm (2 inches, tolerance 0.0000/+0.0010 inches), Outer Diameter: 112.71 mm 4.4375 inches (mm), total width 30.16 mm (1.1875 inches), inner ring width 26.988 mm, outer ring width 20.638 mm, minimum chamfer of inner ring 2.5 mm, minimum chamfer of outer ring 2.0 mm, inner hole to shaft fit tolerance k6 (+0.015/+0.001 mm), end face runout ≤0.02 mm
Load and Speed: Basic dynamic load rating Cr=112 kN, basic static load rating C0r=135 kN, grease lubrication limiting speed 3200 r/min, oil lubrication limiting speed 4000 r/min, suitable for heavy-duty, low-to-medium speed conditions
Compatible Models: Cat 320D/330C excavators (slewing gearbox), 966H loaders (drive axle), C9 engines (camshaft end), 140M graders (rear axle differential) Cat® Parts Assembly Fit: Compatible with a 50.8 mm diameter shaft (tolerance k6, +0.015/+0.001 mm), bearing housing bore diameter 112.71 mm (tolerance H7, +0.030/0 mm). During installation, axial clearance needs to be adjusted to 0.03-0.06 mm. An interference fit (inner ring interference with shaft 0.006-0.015 mm) and a clearance fit (outer ring clearance 0.006-0.018 mm) are used.
Installation and Maintenance Points: Before installation, clean the bearing, journal, and bearing housing bore. Check for scratches, rust, and cracks. Measure the dimensions of the journal and bearing housing bore to ensure the fit meets requirements. The journal fillet radius should be ≤2.5 mm to avoid stress concentration.
Install the bearing using a heat-fit method (heating the inner ring to 80-100℃) or a press-fit 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 0.03-0.06 mm to ensure normal bearing operation.
Maintenance Recommendations: Check the bearing temperature, vibration, and lubrication condition every 1800 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 4500 hours. If the bearing exhibits abnormal noise, jamming, or wear exceeding 0.10 mm, replace it immediately to prevent shaft damage.
