CAT 538-6704 BEARING-SEM

CAT 538-6704 is a Caterpillar SEM series single-row deep groove ball bearing, primarily used in components such as hydraulic pumps and gearboxes in engineering machinery. It bears radial loads and assists in axial positioning, is suitable for medium and low speed and medium and light load conditions, ensures stable operation of the transmission system, and is an important support component in power transmission. The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 538-6704, Type: Single-row deep groove ball bearing (with dust cover, double-sided stamped steel plate seal), Material: 100Cr6 high carbon chromium bearing steel (quenched + tempered, hardness HRC60-64), Weight: Approx. 0.32 kg, Suitable Temperature: -40℃ to +120℃, Surface Treatment: None (relies on lubrication for rust prevention), Mounting Method: Interference fit + Shoulder positioning (Cat® Parts)

Key Dimensions
Inner Diameter: 65 mm (Tolerance P6, 65.000-65.013 mm), Outer Diameter: 120 mm (Tolerance P6, 119.985-120.000 mm), Width: 23 mm (Tolerance ±0.1 mm), Chamfer: 1.5×45°, Radial Clearance: C3 group (0.018-0.038 mm), Suitable Shaft Diameter 65 mm (tolerance k6), bearing housing bore diameter 120 mm (tolerance J7)

Compatible Models and Parts: Compatible with Cat 326D/330D excavator boom cylinder connecting rod bearing, 966GC loader gearbox input shaft support, and D7E bulldozer hydraulic pump drive shaft bearing. One piece per shaft, used to withstand pure radial loads or small amounts of bidirectional axial loads. Suitable for Cat® Parts operating at speeds ≤2800 rpm.

Performance Parameters: Basic rated dynamic load Cr 72 kN, basic rated static load Cor 45 kN, limiting speed (grease lubrication) 3200 rpm, (oil lubrication) 4000 rpm, fatigue life ≥20000 hours (under rated load). Suitable for mineral oil, synthetic grease, and other lubricating media. Can work stably under vibration conditions.

Structural and Performance Advantages: Reliable sealing and dustproof: Double-sided stamped steel plate dust cover design effectively prevents dust and impurities from entering the bearing, suitable for harsh working conditions of outdoor construction machinery, and extends the service life of lubricating grease. Material and Heat Treatment Optimization: The 100Cr6 bearing steel undergoes precision heat treatment, achieving a P6 grade precision for the rolling elements and raceways, ensuring smooth operation at low and medium speeds and reducing vibration and noise.

Radial Clearance Adaptability: The C3 group radial clearance design accommodates thermal expansion and contraction caused by temperature changes in operating conditions, preventing jamming while ensuring rotational flexibility.

High Versatility: The mature deep groove ball bearing structure is suitable for various installation scenarios, requiring no complex positioning structures, facilitating easy installation and maintenance, and adapting to the transmission and hydraulic systems of different machine models using Cat® Parts.

Installation and Maintenance Points: Before installation, clean the shaft and bearing housing bore to remove oil and impurities, and check for rust and rolling element sticking. Install using hot mounting (oil temperature 80-90℃) or cold pressing method, ensuring the bearing end face fits snugly against the shaft shoulder without misalignment. After installation, the radial clearance should meet the C3 group requirements.

Lubrication compatibility: For grease lubrication, use lithium-based grease (such as Cat DEO-ULS), filling the bearing to 1/3-1/2 of its internal space; for oil lubrication, ensure the oil level reaches the center of the lowest rolling element, and change the lubricating oil regularly to prevent contamination.

Maintenance every 2000 hours: Check bearing temperature (≤80℃) and vibration value (≤0.5 mm/s). If abnormal noise, temperature rise, or excessive clearance occurs, replace the bearing immediately to prevent component damage.

Prioritize original equipment manufacturer (OEM) parts. Aftermarket parts may have insufficient material purity or dimensional inaccuracies, easily leading to premature wear, seizure, and other malfunctions.