CAT 257-2177 Cylindrical Roller Bearing

CAT 257-2177 is a Caterpillar original single-row cylindrical roller bearing with cage (NJ type, single flange inner ring / double flange outer ring, separable structure). It is compatible with the planetary carrier of the Cat 320D2/323D2 excavator slewing gearbox and the second shaft of the 966M loader gearbox. Its core design is to withstand heavy radial loads under medium-to-high speed conditions, allowing for slight axial float in the shaft system. It is suitable for power transmission systems such as gearboxes and differentials. The following is professional structured information:

Core Technical Parameters (Professional Version)

Item Details
Basic Attributes
Model 257-2177, Type: Single-row cylindrical roller bearing (NJ type, single flange inner ring / double flange outer ring), Compatible with the second shaft of Cat medium and large equipment gearboxes, planetary carrier of slewing gearboxes, and differential input shaft. Material: High carbon chromium bearing steel (GCr15, hardening hardness HRC 60-64), Inner diameter φ80 mm (compatible with φ80 mm) Shaft diameter), outer diameter φ140 mm, total width 32 mm, single weight approximately 1.48 kg, rated radial dynamic load 112 kN, rated radial static load 128 kN, operating temperature -40℃ to +120℃, compatible shaft tolerance h6, compatible seat tolerance H7, suitable for medium to high speed (≤3000 rpm), heavy radial load conditions, allowable axial float of inner ring relative to outer ring ≤0.5 mm. Key dimensions: inner diameter tolerance 0/-0.015 mm, outer diameter tolerance +0.025/-0.010 mm, width tolerance ±0.15 mm, roller diameter φ12 mm, roller length 22 mm, number of rollers 18, cage made of stamped steel plate (SPCC, thickness 1.2 mm, galvanized for corrosion protection), flange height 8 mm, flange thickness 3 mm, chamfered ends. 1.0×45°, coaxiality ≤0.02 mm, radial clearance C3 group (0.020-0.035 mm)

Material and Manufacturing Process: Bearing steel GCr15, quenched and tempered (martensitic structure, retained austenite ≤5%, hardness HRC 60-64, tensile strength ≥1800 MPa), raceway surface ultra-fine ground (roughness Ra≤0.08 μm), rollers machined with convexity (logarithmic curve), contact stress reduced by 15%, cage is stamped steel plate + riveted structure, roller-cage clearance 0.1-0.2 mm, grease lubrication limiting speed 2800 rpm, oil lubrication limiting speed 4000 rpm

Compatible Models: Cat 320D2/323D2/326D2 excavator rotary gearbox planetary carrier, 966M/972M loader gearbox second shaft, D6K/D7E This bulldozer differential input shaft and 320D2 hydraulic pump drive shaft are used for radial support in the power transmission system. They are compatible with shafts with a diameter of φ80 mm and are installed in the gearbox housing/reduction gearbox bearing seat. They bear heavy radial loads and allow for slight axial float.

Assembly Fit: Interference fit with the shaft (interference 0.010-0.015 mm), clearance fit with the seat (clearance 0.005-0.015 mm). Rear end face runout ≤0.05 mm, no jamming during rotation, axial movement ≤0.5 mm, compatible shoulder diameter ≥90 mm, compatible seat hole depth ≥32 mm.

Installation and Maintenance Points: Before installation, clean the journal, bearing seat, and bearing. Check the bearing raceway for damage and the rollers for rust. Install the inner ring using the hot-fit method (oil temperature 80-100℃, heating time 15-20 minutes). Do not directly strike the bearing end face to prevent deformation.

After installation, check for smooth rotation and no abnormal noise. Inspect every 1000 hours. Replace immediately if the bearing radial clearance is >0.1 mm or pitting/scratching is observed on the raceway.

Lubrication and Maintenance: Before installation, add Cat-specific extreme pressure lithium-based grease (NLGI 2, dropping point ≥180℃) to the bearing. For the transmission system, it is recommended to use Cat DEO-ULS 15W-40 engine oil for lubrication. Change the lubricant every 2000 hours to ensure adequate lubrication and reduce wear.