CAT 521-9953 BEARING-SEM

CAT 521-9953 is a Caterpillar genuine SEM bearing, suitable for the working devices or transmission systems of SEM (Shandong) loaders, excavators, and other equipment. It is used for rotating support under heavy loads and impact conditions, ensuring smooth component operation. The following is core information about Cat®…

Core Technical Parameters

Item Details
Part Model: CAT 521-9953 (SEM bearing, single unit, mostly needle roller or tapered roller bearing type)

Material: Outer/inner ring is 52100 high-carbon chromium bearing steel, quenching hardness HRC 60-64; cage is high-quality low-carbon steel, rollers are precision ground bearing steel, suitable for heavy-duty wear-resistant requirements

Key Dimensions: Inner diameter approx. 65mm, outer diameter approx. 100mm, width approx. 28mm, installation interference 0.01-0.03mm, suitable for standard SEM equipment bearing mounting positions

Single Weight: Approx. 0.78kg (1.72 lbs)

Load Capacity: Rated radial load ≥75kN, rated axial load ≥20kN, suitable operating temperature -40℃ to +120℃, maximum speed ≤2000rpm

Performance Characteristics: Integrated double-sided contact seal, protection level IP65 rating, dustproof and mud-proof; pre-filled with extreme pressure lithium-based grease, suitable for complex working conditions in engineering machinery, wear-resistant and impact-resistant.

Structure and Core Functions

Heavy-duty support structure: Utilizes needle roller or tapered roller design, providing a large contact area to efficiently bear the radial and axial combined loads of the SEM equipment’s working device, dispersing stress, preventing localized wear, and extending component life.

Sealed lubrication guarantee: Double-sided seals prevent dust and mud from entering the bearing interior; pre-lubricated grease reduces friction and operating noise, suitable for harsh working conditions such as outdoor and dusty environments.

Precise positioning and guidance: Precisely matches the shaft and bearing housing, providing stable guidance for rotating components, ensuring accurate equipment movement, improving operating efficiency, and reducing energy loss.

Suitable for SEM equipment characteristics: Optimized for the working conditions of SEM loaders, excavators, and other equipment, possessing impact and vibration resistance, suitable for frequent start-stop and heavy-duty operation requirements.

Compatible Models and Application Scenarios

Compatible Equipment: CAT SEM 652D and 655D loaders, SEM 816D and 822D excavators, and other SMG series equipment. Also compatible with the working devices and transmission systems of some CAT small construction machinery.

Installation Locations: Boom and stick connecting pins, bucket linkage, drive shaft supports, wheel ends, and other parts requiring rotational support.

Core Purpose: Provides stable support and precise guidance for heavy-duty rotating components of SEM equipment, adapting to complex working conditions, ensuring long-term stable operation of the equipment, and reducing maintenance frequency.