CAT 538-4278 BEARING

CAT 538-4278 is a genuine Caterpillar tapered roller bearing, commonly used in the drive axle, final drive, or differential of loaders, excavators, and other equipment. It is compatible with CAT 950H/966H loaders, 329D/336D excavators, and other models. It can withstand radial and bidirectional axial combined loads, ensuring smooth operation of transmission components and extending equipment life. (Cat®…)

Core Technical Parameters

Item Details
Part Model: CAT 538-4278 Tapered Roller Bearing, Original Part Number: 5384278, no official direct replacement model. For non-original parts, refer to tapered roller bearings of the same specification.

Material: Inner ring, outer ring, and rolling elements are made of high-carbon chromium bearing steel (GCr15), with a hardness of HRC 60-64 after quenching. The surface is phosphated for corrosion protection. The cage is made of stamped steel plate, offering high strength and suitability for high-speed operation. The sealing ring is made of nitrile rubber (NBR), oil-resistant and temperature-resistant from -40℃ to 120℃.

Key Dimensions: Inner diameter 100mm, outer diameter 180mm, width 46mm, number of rollers 18, roller diameter 16mm, inner ring large end face diameter 135mm, outer ring small end face diameter 150mm, suitable taper 1:12, conforms to ISO 355 standard size series.

Compatible Models: CAT This drivetrain is used in the main reducer of the drive axle, the planetary gear set of the final drive, and the half-shaft support of the differential in 950H/966H loaders, 329D/336D excavators, and D8R bulldozers. It is suitable for heavy-duty, high-speed applications.

Performance Characteristics: It can withstand a radial load of 220kN and an axial load of 120kN. The limiting speed is 3000r/min. The operating temperature is -40℃ to 120℃. NBR seals prevent dust and moisture intrusion, making it suitable for harsh working conditions in construction machinery and ensuring transmission system stability.

Core Functions and Structure:

Composite Load Bearing: The special structure of the tapered rollers can simultaneously withstand radial and bidirectional axial loads, adapting to the combined force requirements of the drive axle and final drive, preventing axial movement of components and ensuring transmission accuracy.

High-Efficiency Transmission: High-carbon chromium bearing steel and precision-machined rollers reduce friction loss, improve transmission efficiency, adapt to high-speed conditions, reduce equipment energy consumption, and extend the service life of transmission components.

Sealing and protection: The nitrile rubber sealing ring forms a reliable seal, preventing external dust and moisture from entering the bearing and preventing grease leakage. It is suitable for dusty and humid outdoor working conditions, reducing bearing wear and failure.