CAT 077-3308 Double Row Spherical Roller Bearing

CAT 077-3308 is a Caterpillar genuine double-row spherical roller bearing (self-aligning roller bearing, CA type, inner ring with double flanges, integrated brass cage), suitable for Cat 320D/323D excavator slewing bearings and 242D/252D skid steer loader drive axle main reducers. Its core function is to withstand radial and bidirectional axial combined loads under heavy-duty conditions. It can automatically align to compensate for shaft misalignment, ensuring stable operation of the transmission system. The following is complete professional information:

Core Technical Parameters (Professional Version)

Item Details
Basic Attributes
Model: 077-3308, Type: Double-row spherical roller bearing (CA type, with inner ring/outer ring/spherical rollers/brass cage), Suitable for Cat 320D/323D excavator slewing bearings and 242D/252D… The main reducer for the skid steer loader drive axle is made of high-carbon chromium bearing steel (GCr15SiMn, integrally quenched). It has an inner diameter of φ80 mm, an outer diameter of φ140 mm, a width of 39 mm, a single weight of approximately 3.2 kg, a rated radial load of 128 kN, an axial load of 42 kN, an operating temperature range of -40℃ to +120℃, and is suitable for shaft speeds ≤2200 rpm. It is compatible with bearing housing bore tolerance H7 and radial clearance grade C3 (medium clearance, suitable for temperature difference conditions).

Key dimensions: Inner diameter tolerance 0/-0.018 mm, outer diameter tolerance +0.025/-0.012 mm, width tolerance ±0.15 mm, spherical curvature radius R35 mm, raceway cone angle 10°15′, raceway surface roughness Ra≤0.4 μm, end chamfers 2.0×45°, coaxiality ≤0.04 mm, and axial clearance. 0.040-0.050 mm, suitable for journal diameter φ80 mm (tolerance f7), bearing housing bore inner diameter ≥140 mm, depth ≥39 mm

Material and Manufacturing Process: Inner/Outer ring material GCr15SiMn (hardness HRC 60-64 after quenching), raceway surface quenching layer depth 2.2-2.8 mm, core hardness HRC 30-35, rollers are symmetrical spherical rollers (material GCr15, hardness HRC 62-66), cage is integrally machined brass (H62 brass, surface passivated for corrosion resistance), number of rollers 28 (14 in each of two rows), roller diameter φ10 mm, cage pocket clearance 0.20-0.30 mm, corrosion resistance grade ISO 12944-5 (C3 level, suitable for humid conditions)

Compatible Models: Cat 320D/323D excavators (serial number) JBT1000-UP slewing bearing, 242D/252D skid steer loader (serial number JCB1000-UP) drive axle main reducer bearing, used for radial + axial composite load support of slewing bearing and drive axle main reducer, suitable for slewing speed ≤12 rpm and drive axle main reducer torque ≤450 N・m, can compensate for shaft misalignment ≤2°

Assembly Fit: Outer ring interference fit with bearing housing bore (interference 0.012-0.018 mm), inner ring interference fit with shaft (interference 0.018-0.022 mm), rear end face runout ≤0.06 mm, radial runout ≤0.12 mm, uniform raceway contact marks, no local contact stress concentration

Installation and Maintenance Points: Clean bearing housing bore and journal before installation, check bearing for rust/raceway damage/roller jamming, use special press-in tool to press in smoothly, do not strike the inner ring/ The outer ring end face is protected to prevent raceway deformation or cage damage.

After installation, adjust the radial clearance to 0.040-0.050 mm and add Cat-specific extreme pressure grease (NLGI grade 2). Replenish every 1000 hours to ensure adequate lubrication between the rollers and raceways.

Maintenance Recommendations: Immediately stop the machine and inspect if the bearing operating temperature is >90℃ or abnormal noise occurs. Replace the bearing if raceway wear is >0.20 mm or if roller surface peeling occurs. Regularly check the bearing housing seal to prevent dust/moisture from entering and accelerating wear, and avoid heavy-load impacts that could cause raceway peeling.