CAT 9T-3876 55mm Inner Diameter Tapered Roller Bearing

CAT 9T-3876 is a genuine Caterpillar cylindrical roller bearing assembly, commonly used for supporting hydraulic pump drive shafts, gearbox input shafts, or transfer case output shafts. It is suitable for the hydraulic and transmission systems of excavators, loaders, bulldozers, and other equipment, and can withstand medium-to-high speed and medium-to-heavy radial loads, ensuring smooth shaft operation.

Core Technical Parameters

Item Details
Part Model: CAT 9T-3876 Cylindrical Roller Bearing Assembly (including inner ring, outer ring, rollers, cage, some with seals)

Material: Inner/outer rings are bearing steel (GCr15), surface hardened to HRC 61-65; rollers are high-carbon chromium bearing steel; cages are brass/engineering plastic, wear-resistant, fatigue-resistant, suitable for medium- and high-speed applications.

Key Dimensions: Inner diameter approx. 38-42mm, outer diameter approx. 62-68mm, width approx. 20-25mm, weight approx. 0.7kg (1.6 lbs), precision tolerances, suitable for interference fit between shaft and bearing housing.

Suitable Machines: Excavators 320D/336D, Loaders 966K/980M, Bulldozers D6N/D9T, etc., used for supporting hydraulic pump drive shafts, gearbox input shafts, and transfer case output shafts.

Performance Characteristics Cylindrical roller design for high radial load capacity; cage-separated rollers reduce friction and noise, suitable for medium to high speeds (≤5000rpm); low coefficient of friction suitable for continuous operation.

Core Functions and Structure

Radial Load Capacity: Cylindrical rollers evenly bear radial force at multiple contact points, suitable for medium to heavy loads in shaft systems such as hydraulic pumps and gearboxes, preventing shaft bending and deformation, and ensuring transmission accuracy.

High-Speed ​​Smooth Operation: The cage guides the rollers to roll in an orderly manner, reducing friction and collision between rollers, lowering operating noise and heat generation, suitable for medium to high-speed continuous operation, and improving transmission efficiency.

Precise Positioning: The inner ring has an interference fit with the shaft, and the outer ring has a clearance fit with the bearing housing, providing radial positioning for the shaft, preventing eccentric operation, and extending the life of the shaft and bearing.

Sealing Protection (some models): Equipped with contact/non-contact seals to prevent oil and dust from entering, protecting the rollers and raceways, suitable for hydraulic oil, gear oil, and other operating conditions.

Installation and Maintenance Points

Installation Specifications
Clean the journal, bearing housing, and bearing assembly. Check the journal diameter, roundness, and surface roughness to ensure they meet the fit requirements (HRC≥60, Ra≤0.8μm).

Use hot fitting (oil temperature 80-100℃) or cold pressing for installation. Do not directly strike the inner/outer rings to avoid component deformation or roller jamming. After installation, check the clearance to ensure smooth operation.

Control the installation interference (0.01-0.03mm) to prevent bearing loosening or excessive tightness, which can lead to overheating and wear. Tighten the bearing housing end cap to the specified torque.

Maintenance Recommendations
Check every 1000-1500 working hours: for abnormal noise, overheating, aging of the seals, and wear on the journal. Replace the bearing if the clearance is >0.2mm.

Regularly change the hydraulic oil/gear oil to keep the oil clean and prevent impurities from entering the bearing, causing wear on the raceways and rollers, leading to premature failure.