CAT 342-4640 Self Aligning Bearing

CAT 342-4640 is a Caterpillar single-row tapered roller bearing (with cage, compatible with gearbox/drive axle differentials) used to withstand radial and bidirectional axial combined loads. It is suitable for differential side covers/planetary carrier supports in equipment such as Cat 950M/962M loaders and 770G mining trucks. The following is professional structured information.

Core Parameters (Professional Version)

Item Details
Basic Attributes Model 342-4640, Single Row Tapered Roller Bearing (including inner ring/outer ring/rollers/cage), Inner Diameter 76.2 mm (3.000 in, tolerance JS6: ±0.015 mm), Unit Weight 1.86 kg, Preload Axial Clearance 0.02–0.05 mm, Quantity per Unit 1 (Differential Right End Cover)

Key Dimensions Inner Diameter φ76.2 mm (Tolerance 0–+0.02 mm), Outer Diameter φ139.7 mm (5.500 in, tolerance 0–-0.03 mm), Width 36.5 mm (1.437 in, tolerance ±0.1 mm), Number of Rollers 18, Roller Diameter 12.7 mm, Taper Angle 12°30′, Inner Ring Large End Diameter φ105 mm, Outer Ring Small End Diameter φ98 mm

Material and Manufacturing Process: Inner/outer rings are made of chromium-molybdenum alloy steel (40CrMnMo, quenched and tempered HB 280–320, surface hardened HRC 60–64, hardened layer ≥2 mm); rollers are made of high-carbon chromium bearing steel (GCr15, HRC 62–66); cage is made of stamped low-carbon steel (SPCC, surface galvanized and passivated); no seal, open design.

Performance Parameters: Rated dynamic load C=148 kN, rated static load C0=212 kN, limiting speed 3200 r/min (grease lubrication)/4500 r/min (oil lubrication), operating temperature -40℃ to +120℃, suitable journal hardness HRC 58–62 (hardened layer ≥1.5 mm), suitable seat bore φ139.7 J7 (+0.01–-0.01 mm)

Compatible Models: Loaders 950M/962M/972M, mining trucks 770G/772G, graders 140M/160M, compatible differential housing side cover mounting hole φ139.7 mm, compatible shaft diameter φ76.2 mm (tolerance h6: 0–-0.019 mm)

Installation and Maintenance Points: Before installation, clean the journal (surface roughness Ra≤0.8 μm, no burrs/scratches) and seat hole. Press in evenly using hydraulic pressure or a special pressure sleeve (press the outer ring end face, pressing force ≤80 kN). Do not strike the inner ring. The journal needs to be tempered to HB 220–250 and surface hardened to HRC 58–62 (hardened layer ≥1.5 mm). Clearance Control: After installation, measure the axial clearance with a dial indicator to ensure it is 0.02–0.05 mm. Control the preload by adjusting shims (0.05 mm/0.1 mm specifications). For heavy-load conditions, a preload of 0.01–0.03 mm is recommended.

Lubrication Requirements: Apply extreme pressure lithium-based grease (NLGI Grade 2) before installation. During operation, lubrication relies on transmission oil (API GL-5 85W-90, oil level should submerge the bearing to 1/3 of its height). Check the oil quality/level every 1000 hours to avoid dry friction leading to roller pitting.

Troubleshooting: If abnormal noise/temperature rise occurs, first check the bearing clearance (wear > 0.1 mm requires replacement), roller spalling, or insufficient lubrication. If necessary, replace the bearing and correct the shaft radial runout to ≤ 0.05 mm.