Deep Groove Ball Bearings 6306-2Z/C3 SKF

The SKF 6306-2Z/C3 is a high-reliability deep groove ball bearing, engineered for general industrial applications requiring high speed, simple installation and dust protection. Fully compliant with ISO 355 and ISO 492 standards, its suffixes denote key configurations: 2Z for double-sided metal shields, C3 for increased radial internal clearance to accommodate thermal expansion. Distinguished by its compact structure, high rotational stability and cost-effectiveness, it integrates reliable load-bearing capacity and dust-proof performance, making it a versatile choice for medium-load, high-speed general machinery.

1. Detailed Dimensional Parameters: Conforming to international standards, the bearing has an inner diameter (d) of 30mm, outer diameter (D) of 72mm, and width (B) of 19mm. The minimum chamfer size (rₘᵢₙ) is 1.5mm, single weight is 0.35kg. Its tolerance grade is P0 (ISO 492), with inner/outer diameter tolerance of IT6 and width tolerance of IT7. The basic dynamic load rating (C) is 25.5kN, basic static load rating (C₀) is 15.2kN, reference speed (grease lubrication) is 6300r/min, limiting speed (oil lubrication) is 8500r/min. The C3 internal clearance (0.030-0.065mm) adapts to high-temperature operations.

2. Specific Material Description: Inner ring, outer ring and ball rolling elements are made of high-carbon chromium bearing steel (AISI 52100/SUJ2), refined by vacuum degassing to reduce non-metallic inclusions. After precision heat treatment, it reaches 60-64 HRC, featuring excellent wear resistance, fatigue strength and dimensional stability. The retainer is pressed steel (SPCC), with good impact resistance and wear resistance, ensuring stable ball guidance. The 2Z metal shields are carbon steel (SPCEN), providing effective dust protection without affecting rotational flexibility.

3. Core Processing Technology: Key processes follow SKF’s strict standards: closed-die forging (dense internal structure), CNC turning (Ra ≤ 0.3μm surface roughness), controlled atmosphere heat treatment (nitrogen-hydrogen atmosphere to avoid oxidation), precision grinding and superfinishing (raceway roughness Ra ≤ 0.04μm). The metal shields are precision fitted to ensure dust tightness, and the C3 clearance is accurately controlled via precision grinding, optimizing thermal adaptability.

4. Service Life: Under standard conditions (3500r/min, radial load 8kN, proper lubrication, clean environment), the L₁₀ basic rated life (90% reliability) is 28,000 operating hours, calculated per ISO 281:2007. Key influencing factors: lubrication quality, contamination, installation accuracy and load; insufficient lubrication or excessive dust can reduce service life by 30-45%.

5. Application Scenarios and Industries: Widely used in general machinery, automotive accessories, electric motors, textile and agricultural machinery. Typical applications: small gearboxes, electric motor shafts, centrifugal pumps, conveyor rollers and textile machinery components. It is suitable due to its compact structure, high-speed adaptability, 2Z dust protection and C3 thermal adaptability, fitting medium-load, high-speed and low-maintenance scenarios.

6. Basic Maintenance Requirements: Maintenance cycle: 1800 operating hours. Lubrication: Lithium-based grease (NLGI 2), filling amount 15-25% of bearing free space; re-lubricate every 1200-1800 hours. Cleaning: Clean with clean kerosene; avoid corrosive cleaners. Inspection: Check for abnormal noise, temperature rise and grease leakage; replace lubricant if deteriorated.

7. Installation Precautions: Pre-installation: Keep area clean, remove burrs from shaft/housing, check fitting surface roughness (Ra ≤ 0.8μm). Installation: Apply thin oil film, press evenly on inner ring (no tapping), ensure coaxiality ≤ 0.02mm. Fastening torque: 50-70N·m for bearing seat bolts. Post-installation: Rotate manually to check jamming; temperature ≤ 70℃ after 30 minutes. Safety: Wear protective gloves/goggles, use specialized lifting tools.