CAT 138-2174 Self Aligning Bearing

CAT 138-2174 is a Caterpillar self-aligning spherical plain bearing (maintenance-free), suitable for articulated joints in engineering machinery. It compensates for installation misalignment and shaft deflection, and can withstand radial loads and bidirectional angular misalignment. The following is raw data and does not include replacement parts information for Cat®…

Core Technical Parameters (Raw Data)

Item Details
Basic Attributes Model 138-2174, Type: Self-aligning spherical sliding bearing (maintenance-free), Material: Outer ring/inner ring is bearing steel + PTFE composite layer, Single weight 1.85 kg, Operating temperature: -40℃ to +120℃, Suitable radial load ≤180 kN, Suitable shaft diameter 50.8 mm, Fit tolerance H7, Corrosion resistance ≥120 hours salt spray, Surface treatment: Outer ring blackened, inner ring PTFE composite layer, Hardness: Outer ring HRC 58-62, Inner ring friction layer hardness HB 30-50, Fit clearance 0.020-0.040 mm

Key Dimensions (Metric/Imperial) Inner diameter 50.8 mm (2.000 in), Outer diameter 90.5 mm (3.5625 in), Outer ring length 57.9 mm (2.280 in), Wall thickness 19.85 mm, chamfer C1.5 mm, flatness ≤0.02 mm, surface roughness Ra≤0.8 μm, inner diameter tolerance +0.010/-0.005 mm, outer diameter tolerance +0.015/-0.010 mm, length tolerance +0.10/-0.05 mm, roundness ≤0.015 mm

Performance Parameters: Coefficient of friction ≤0.05 (dry state), elastic modulus 208 GPa, Poisson’s ratio 0.27, coefficient of thermal expansion 12.0×10^-6/℃, compressive strength ≥1500 MPa, shear strength ≥580 MPa, fatigue limit ≥480 MPa (10^7 cycles), angular deviation compensation capability ≤3°, assembly interference 0.010-0.020 mm

Structure and Adaptation Characteristics: Composite layer friction-reducing structure: inner ring PTFE The composite layer provides a low-friction surface, while the outer bearing steel ring ensures load-bearing strength. It is suitable for unlubricated or boundary-lubricated conditions, requiring no maintenance and offering wear resistance, reducing frictional losses at hinged joints.

Self-aligning function: The spherical contact design compensates for angular deviations within ±3°, adapting to installation coaxiality errors and shaft deflection, reducing localized stress concentration and improving component operational stability.

Universal compatibility: Compatible with connecting rods, rocker arms, and other hinged joints on Caterpillar loaders, excavators, and other equipment. Suitable for frequent swinging and impact load conditions, installation is convenient, and no additional lubrication system is required.

Compatible models and application scenarios:

Loaders: Boom connecting rods and steering rocker arm hinges in models such as 938G and 950G, suitable for frequent material loading and unloading movements, ensuring flexible steering and working device operation.

Excavators: Stick connecting rods and boom support hinges in models such as 312D and 315D, suitable for heavy-load and swinging conditions in excavation operations, improving the reliability of the working device.

Other: Compatible with the articulated joints of the working devices of some Caterpillar graders and bulldozers, suitable for high-intensity operation under harsh conditions.

Installation and Maintenance Points (Original Data)

Installation: Clean the bearings and mounting seats, ensuring they are free of oil and metal shavings. Inspect the bearings for cracks and ensure the composite layer is intact and dimensions meet requirements.

Cold press installation (pressing force ≤ 80 kN), ensuring an interference fit (interference 0.010-0.020 mm). After installation, the coaxiality should be ≤ 0.02 mm, requiring no additional lubrication.

After installation, check the inner diameter and rotational flexibility. Run the bearings for 30 minutes, monitoring for any jamming, abnormal noise, or abnormal heating.

Maintenance: Check bearing wear and composite layer condition every 1500 hours. Replace bearings immediately if wear exceeds 0.20 mm or the composite layer has detached.

Regularly check the mounting seat tightness. Use a dedicated puller when disassembling; do not pry or pry, as this may damage the bearings and mounting seats.