Description
CAT 521-9961 BEARING-SEM
| CAT 521-9961 BEARING-SEM |
| CAT 473-8301 ROLLER-GUIDE |
| CAT 3H-8363 RACE |
| CAT 521-9953 BEARING-SEM |
| CAT 153-6850 COLLAR |
| CAT 122-6632 197mm Inner Diameter Retainer |
| CAT 538-3071 BEARING-SEM |
| CAT 5M-7966 SLEEVE |
The CAT 521-9961 is a Caterpillar genuine SEM series dedicated roller bearing. Its core applications are in the rotating/oscillating parts of engineering machinery chassis, transmissions, or hydraulic linkages, providing radial load support, vibration damping, and wear protection. It is compatible with heavy equipment such as CAT 966/972 loaders and 330/345 excavators. The following are its key specifications.
Core Technical Parameters
Item Details
Part Model: CAT 521-9961 (SEM Roller Bearing, Single Unit)
Material: Inner/Outer Ring: 52100 Chromium Bearing Steel, Tempered + Quenched, Hardness HRC 60-64; Rollers: High Carbon Chromium Steel, Cage: Stamped Steel Plate, Wear-Resistant and Fatigue-Resistant
Key Dimensions: Inner Diameter: 50mm, Outer Diameter: 80mm, Width: 20mm, Roller Diameter: 8mm, Number of Rollers: 12, Chamfers at Both Ends: 3×45°, Installation Clearance: 0.03-0.06mm
Single Weight: Approx. 0.48kg (1.06 lbs)
Load and Speed: Dynamic Radial Load Capacity: 120kN, Static Radial Load Capacity: 85kN, Suitable Maximum Speed ≤3000rpm, Withstands Operating Conditions from -40℃ to +120℃
Core Features Roller structure adaptable to heavy-duty radial forces; lightweight and rigid stamped cage; dustproof and leak-proof sealing lip; pre-lubricated design for direct installation.
Structure and Core Functions:
Heavy-duty roller support structure: Made of 52100 chrome steel with a quenching treatment; the rollers and inner and outer raceways are precisely matched, efficiently bearing the radial loads of heavy equipment and avoiding premature damage caused by localized stress concentration.
Sealing and Lubrication Design: Integrated contact sealing lip prevents dust and mud from entering the bearing; pre-filled with extreme pressure lithium-based grease, suitable for impact and vibration conditions, reducing maintenance frequency.
Precise Positioning and Vibration Reduction: Fixed in the mounting holes of connecting rods, rocker arms, or drive shafts, providing stable rotation/oscillation guidance for shaft parts, absorbing vibrations during equipment operation, and reducing component wear and noise.
Suitable for Stable Operation Under Multiple Conditions: Adaptable to complex conditions such as high-frequency vibration and heavy-load start-stop in engineering machinery; the cage-separating rollers prevent friction, ensuring bearing stability and long service life under high loads.
Compatible Models and Application Scenarios
Compatible Equipment: CAT 966K/XE and 972K/XE loaders, 330D2 and 345D2 excavators, some mining truck chassis and hydraulic actuators.
Installation Locations: Hydraulic cylinder lugs, boom/stick connecting rod pins, steering knuckle swing shafts, drive shaft support seats, and other parts requiring radial support and swing.
Core Purpose: Provides radial support for connecting rods and shafts in heavy equipment, reducing friction and impact, ensuring stable operation of the chassis, hydraulic and transmission systems under heavy load conditions, and extending component lifespan.
