51318 Single Direction Thrust Ball Bearing , Precision Industrial Machinery Bearings

Basic Parameters

• Bore diameter (d):90mm
• Outer diameter (D):155mm
• Thickness (T):50mm (single bearing)
• Type:Single-direction thrust ball bearing (51000 series)
• Weight:Approximately 3.67~3.88kg (3.67kg for SKF models, 3.88kg for NACHI)
• Structure:Single-row, non-separable design, consisting of a flat housing washer, shaft washer, and steel balls. Cage material is typically pressed steel (SKF, HRB), with copper cages available for some models (e.g., 51318M).

Core Performance Specifications

1. Load Capacity
   • Dynamic load rating (Cr):182~213kN (significant brand variation; 182kN for SKF, up to 213kN for NACHI)
   • Static load rating (C0r):440~525kN (highest for NACHI models)
   • Material:
     • Standard: GCr15/SUJ2 high-carbon chromium bearing steel (surface hardness HRC58-62)
     • Optional: Stainless steel (SUS440C) or ceramic (available via customization)
2. Speed & Precision
   • Limiting speed:
     • Grease-lubricated: 1,100~1,500rpm
     • Oil-lubricated: 1,600~2,200rpm (optimized for heat dissipation)
   • Precision class:Standard P0; customizable to P4 for precision equipment
3. Technical Features
   • Axial load-oriented:Only withstands unidirectional axial force; paired mounting (e.g., DB/DF configurations) is required for bidirectional load capacity.
   • Low-friction design:Optimized raceway curvature and cage structure reduce energy loss during high-speed operation.

Structural & Environmental Adaptability

• Mounting fit:
  • Shaft: h8 (recommended tolerance)
  • Housing bore: H8 (compatible with cast iron or steel housings)
• Temperature range:
  • Standard: -20°C to 120°C
  • High-temperature type: Up to 200°C (requires high-temperature grease)
• Sealing options:
  • Open (no seals)
  • Optional: 2RS (double rubber seals) or ZZ (double metal shields) with protection class IP54

Typical Applications

1. Industrial Machinery
   • Heavy-duty presses and forging equipment:Withstands high-pressure axial loads, such as main cylinder support in metal forming machines.
   • Axial positioning of gearboxes:Used in low-speed, heavy-load transmission systems for cranes and mining machinery.
   • Machine tool spindles:Paired with angular contact ball bearings for precise axial positioning in boring machines and grinders.
2. Transportation
   • Railway freight car axle boxes:Withstands vertical loads of trains, demanding high reliability and long service life.
   • Large construction machinery:Axial support for slewing systems in excavators, for example.
3. Precision Equipment
   • Medical imaging devices:Axial support for CT scanner rotating tables, requiring low noise and maintenance-free operation.
   • Food packaging machinery:Stainless steel (SUS440C) variants meet hygienic standards.

Maintenance & Lubrication Guidelines

• Lubrication options:
  • Grease lubrication:Lithium-based grease (NLGI Grade 2) with a filling volume of 1/3~1/2 of the bearing internal space; synthetic polyurea grease (temperature-resistant up to 200°C) is recommended for high-temperature scenarios.
  • Oil lubrication:ISO VG 46-68 mineral oil, used for continuous high-speed operation to enhance heat dissipation.
• Lubrication interval:
  • Normal operating conditions: Every 8,000~12,000 hours (or calculated using the formula tf​=bf​A​)
  • High-temperature/high-pollution environments: Shorten to 4,000 hours, with enhanced sealing protection.

Certifications & Compatibility

• Standards compliance:Conforms to ISO 9001:2015 quality management system; some models are CE-certified.
• Cross-brand replacement:Interchangeable with models such as NSK 51318, NACHI 51318, and HRB 51318. Note differences in cage design (e.g., copper cage M-type).

Customization Options

1. Material upgrades
   • Ceramic hybrid bearings:Si3N4 ceramic balls + steel rings, with 15% higher dynamic load capacity, suitable for high-frequency vibration environments.
   • Stainless steel:SUS440C passes 1,000-hour salt spray tests, meeting standards for food and pharmaceutical industries.
2. Special designs
   • Phosphating coating:Surface treatment reduces friction coefficient and extends wear life.
   • Laser marking:Supports Industrial Internet of Things (IIoT) equipment tracking.

Selection Considerations

1. Load direction:Single-direction design requires paired mounting (e.g., DB/DF configurations) to withstand bidirectional axial forces.
2. Fit precision:Cylindricity error of shafts and housing bores should be controlled within 0.01mm to avoid stress concentration.
3. Temperature compensation:Reserve 0.03~0.05mm axial expansion clearance for high-temperature operating conditions.

Summary

The 51318 thrust ball bearing features high axial load capacity (up to 525kN static) and cost-effectiveness as core advantages, making it widely used in industrial machinery, transportation, and precision equipment. Its standardized design and customizable features (e.g., materials, seals) balance performance and cost. With scientific lubrication and maintenance, it delivers reliable long-term operation in environments ranging from -20°C to 200°C.