CAT 521-9960 BEARING-SEM

CAT 521-9960 is a Caterpillar original equipment manufacturer (OEM) single-row tapered roller bearing assembly for SEM (Shandong Engineering Machinery) equipment. It is commonly used in the transmission systems of loaders, graders, etc., and can withstand combined radial and unidirectional axial loads, making it suitable for heavy-duty and vibration-prone conditions, ensuring stable power transmission. The following are key information.

Core Technical Parameters

Item Details
Part Model: CAT 521-9960 (SEM Compatible Tapered Roller Bearing Assembly)

Material: High carbon chromium bearing steel (GCr15), hardened to HRC60-64, raceway ultra-precision ground, rust-proof surface, fatigue life ≥12000 working hours

Key Dimensions: Inner diameter approx. 70mm, outer diameter approx. 150mm, width approx. 38mm, tapered raceway half-cone angle approx. 12°, inner ring interference fit with shaft (0.01-0.03mm)

Single Weight: Approx. 3.2kg (7.05 lbs)

Compatible Models: SEM 652D/655D loaders, SEM 922 graders, etc., corresponding to the gearbox second shaft, differential, or final drive of CAT 950GC/962GC loaders

Performance Characteristics Rated radial dynamic load ≥130kN, rated axial dynamic load ≥60kN, allowable speed ≤2200rpm, operating temperature -40℃ to +120℃, vibration and shock resistant.

Structure and Core Functions

Combined Load Bearing: Tapered rollers make line contact with the inner and outer rings, efficiently transmitting radial and unidirectional axial loads, adaptable to heavy-duty composite forces, preventing component movement and abnormal wear.

High-Precision Positioning: Stamped steel cage precisely separates the rollers, avoiding skewed friction; raceway roughness Ra≤0.08μm, reducing transmission loss and improving efficiency.

Convenient Assembly and Maintenance: Inner and outer rings are separable, heat-fitted (80-90℃) or cold-pressed into place; the outer ring has an interference fit with the bearing housing, ensuring coaxiality during operation.

Optimized Operating Conditions: The SEM marking plate enhances sealing adaptability for Shantui equipment operating conditions, preventing dust/mud intrusion, suitable for harsh environments such as mines and infrastructure projects.

Suitable Scenarios and Installation/Maintenance Points

Suitable Scenarios: Used in core transmission components such as gearboxes, differentials, and final drives of SEM loaders and graders, suitable for heavy-duty, high-frequency vibration, and impact conditions.

Installation Specifications: Clean the journals and bearing housing bores, ensuring they are free of burrs, oil, and rust; heat-fit or cold-press in, avoiding forceful hammering that could damage the raceways.

After assembly, check the axial clearance (0.05-0.15mm), adjust according to the manual, and add CAT 5K-8591 grease, filling the bearing cavity to 1/3-1/2 full.

Maintenance Recommendations: Check bearing temperature (≤80℃) and noise every 800 working hours. If abnormal, disassemble and inspect for raceway wear, spalling, or cage damage, replacing as needed.

Replenish/replace grease every 2000 working hours. Regularly check seals to prevent leakage and contaminant entry.