CAT 581-8976 BEARING-GD

CAT 581-8976 YM is a Caterpillar self-aligning roller bearing. It features a roller-guided one-piece brass cage and is suitable for heavy-duty applications requiring angular compensation. It is commonly used in the transmission and running gear of excavators, loaders, and other similar machines. It can absorb shaft misalignment errors and withstand bidirectional loads. The following is structured technical and application information.

Core Technical Parameters

Item Details
Basic Attributes Model 581-8976 YM, type is double row self-aligning roller bearing, cage is roller-guided one-piece brass, material is bearing steel + brass, inner/outer ring hardened (hardness 60-64 HRC), single weight approximately 8.6 kg, operating temperature -40℃ to +120℃, lubrication method is grease lubrication (NLGI Grade 2 lithium-based grease), sealing type is contact double lip seal, fit tolerance: inner diameter H7, outer diameter r6

Key Dimensions Inner diameter 120 mm, outer diameter 215 mm, total width 73 mm, chamfer 2×45°, rolling element diameter 28 mm, cage center circle diameter 165 mm, radial clearance 0.12-0.18 mm, center coaxiality ≤0.05 mm, surface roughness Ra≤0.8 μm

Applicable Models and Locations Applicable Cat For 349D2L/352D2L excavators, 972M/980M loaders, and D9T bulldozers, this bearing is installed on the input shaft of the travel reducer, the drive shaft of the slewing bearing, and the boom cylinder hinge point, etc., one piece per location. It is compatible with shaft diameters of 120 mm and has a rated load ≤220 kN.

Performance Parameters: Radial rated static load ≥1250 kN, radial rated dynamic load ≥820 kN, permissible angular deviation ≤0.5°, coefficient of friction ≤0.002 (grease lubrication), limiting speed 2800 rpm (grease lubrication), rated life ≥12000 hours, impact resistance ≥10⁴ times (25 kN instantaneous load).

Structural and Performance Advantages: Brass cage design: Roller-guided one-piece brass cage with high strength and good wear resistance effectively prevents roller misalignment, suitable for high-speed and heavy-load conditions, and extends bearing life.

Excellent self-aligning performance: Allows for ≤0.5° angular deviation in the shaft system, absorbing installation errors and shaft deflection, reducing vibration and noise, and improving transmission efficiency.

Bidirectional load-bearing capacity: The double-row rolling element design can withstand large radial loads and bidirectional axial loads, adapting to complex stress conditions, such as frequent starts, stops, and turns of the traveling mechanism.

Reliable sealing: Contact-type double-lip seal effectively blocks dust, mud, and moisture, preventing grease leakage, suitable for dusty and humid operating environments of construction machinery.

Installation and maintenance points:
Installation process: Clean the journal and bearing housing bore, ensuring they are free of oil, rust, or impurities; install using the hot-fit method (bearing heated to 80-100℃) or the cold-fit method (journal cooled to -40℃), pressing evenly with a special tool to avoid impact; after installation, check the radial clearance and coaxiality to ensure they meet requirements; add grease until overflowing, and install the sealing cap.

Maintenance Cycle: Check bearing temperature, vibration, and grease condition every 1500 hours. If the temperature is abnormal (>80℃), stop the machine for inspection. Replenish grease every 3000 hours, shortening to 1000 hours under harsh operating conditions. Regularly check the seal condition and replace any damaged seals promptly.

Common Faults and Solutions: Overheating is often due to insufficient lubrication or installation misalignment, requiring grease replenishment or reinstallation. Abnormal vibration may indicate rolling element damage or cage deformation, requiring bearing replacement. Seal leakage requires replacing the seal and checking the clearance.