7228AC Angular Ball Bearings Heavy Duty High Load Capacity Bearing

7228AC Angular Contact Ball Bearing: Heavy-Duty, High-Precision Performance

• Bore diameter (d): 140mm
• Outer diameter (D): 250mm
• Width (B): 42mm (single bearing); total thickness 84mm when mounted in pairs
• Contact angle: 25° (suffix "AC" indicates standard angular contact design)
• Weight: Approximately 12.5~13.2kg (single bearing)
• Structure: Single-row, non-separable design with inner/outer rings, paired with balls and cage
• Cage options: Solid brass (for high-speed stability) or bakelite (cost-effective)

• Dynamic load rating (Cr): 228kN (typical value)
• Static load rating (C0r): 198kN (estimated based on size and load relationships)
• Material:
  • Standard: GCr15/SUJ2 high-carbon chromium bearing steel (surface hardness HRC58-62)
  • Optional: Stainless steel (SUS440C) or ceramic (Si3N4 balls + steel rings)

• Limiting speed:
  • Grease-lubricated: 2,200rpm (standard type)
  • Oil-lubricated: 3,000rpm (optimized for heat dissipation)
• Precision class: Standard P0; customizable to P4/P5

• Axial-radial load capability: Single bearing supports radial loads and unidirectional axial thrust
• Mounting configurations: DB (back-to-back), DF (face-to-face), DT (tandem) to enhance rigidity
• Stability design: Optimized raceway curvature and cage structure reduce friction and temperature rise

• Tolerance compatibility: Shaft: H7/k6, Housing: J7
• Temperature range:
  • Standard: -20°C to 120°C
  • High-temperature type: Up to 300°C (requires ceramic materials + high-temperature grease)
• Sealing options:
  • Standard: Open (no seals)
  • Optional: 2RS (double rubber seals) or ZZ (double metal shields) with protection class IP54

• Heavy-duty gearboxes in mining crushers and metallurgical rolling mills
• Large-scale motors for main shafts of chemical pumps or compressors
• Wind turbines pitch drive systems (1.5MW+ models)

• Marine propulsion systems in salt-spray environments
• Railway traction systems for train motors

• CNC machine tool spindles for heavy-duty cutting
• Industrial robotics joint bearings for robotic arms

• Grease: Lithium-based grease (NLGI 2) with 15%-20% filling volume
• Oil: ISO VG 46-68 circulating oil for continuous high-speed operation

• Normal operating conditions: Every 8,000~12,000 hours
• High-temperature/high-pollution environments: Shorten to 4,000 hours

• Standards compliance: ISO 9001:2015, ISO 281 load standards
• Cross-brand compatibility: Interchangeable with models such as NACHI 7228 and SKF 7228 ACDGA

• Ceramic hybrid: Si3N4 ceramic balls + steel rings, with 15% higher dynamic load capacity
• Stainless steel: SUS440C material with corrosion resistance >1,000 hours in salt spray tests

• Phosphating coating: Surface treatment reduces friction coefficient
• Laser-etched coding: High-precision marking supports IIoT equipment tracking