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R Series
Home Deep Groove Ball Bearings R Series

R155-ZZ Shielded Miniature Ball Bearing | 5/32" Bore Precision | 3.967 × 7.938 × 3.175 mm

R155-ZZ Shielded Miniature Ball Bearing | 5/32" Bore Precision | 3.967 × 7.938 × 3.175 mm

The R155-ZZ is a precision-engineered imperial miniature ball bearing specifically developed for applications requiring a 5/32-inch shaft interface. Featuring a dual-shielded ("ZZ") construction, this model provides a robust defense against dust and debris, ensuring the internal raceways remain clean and well-lubricated. This enclosed design makes the R155-ZZ an ideal, "set-and-forget" component for high-speed micro-motors, precision encoders, and small-scale mechanical linkages where reliability and low-maintenance operation are paramount.

R155-ZZ Deep Groove Ball Bearing R Series – High-Speed Stability & Sealed Protection

Constructed for smooth, low-vibration performance, the R155-ZZ excels in micro-mechanical assemblies that demand high rotational accuracy. The non-contact metal shields are meticulously fitted to retain the factory-filled lubricant while preventing contaminant ingress, all without increasing starting torque. Whether integrated into a high-end consumer electronic device or a complex industrial sensor, this bearing delivers consistent power efficiency and whisper-quiet rotation across its entire speed range.

R155-ZZ Shielded Miniature Ball Bearing | 5/32" Bore Precision | 3.967 × 7.938 × 3.175 mm

Comprehensive Applications

Designed for technical designers and procurement managers focused on durable, high-precision 5/32-inch shaft components:

Micro-Electronics & Cooling
  • High-Performance Small DC Motors
  • Specialized Laptop Cooling Fans
  • Micro-Pump Drive Assemblies
  • Automated Consumer Electronics
Precision Instrumentation & Sensors
  • High-Resolution Rotary Encoders
  • Flow Measurement Meters
  • Scientific Lab Stirrers
  • Galvanometer Mirror Scanners
Robotics & Modeling
  • Precision RC Car Drivetrains
  • Drone Motor Hubs
  • Small-Scale Robotics Joint Actuators
  • Miniature Linear Guide Support

Key Performance Features

01. Dual-Sided Metal Enclosure (ZZ)

The R155-ZZ is equipped with two pressed-steel shields that act as a barrier against atmospheric pollutants. This design keeps the high-speed lubricant securely inside the bearing, significantly extending the service life and eliminating the need for periodic relubrication in clean or moderately dusty environments.

02. Standard Imperial Form Factor

With a 3.967 mm (5/32") bore and a 7.938 mm (5/16") outer diameter, this bearing fits perfectly into standard inch-sized housings. Its 3.175 mm (1/8") width provides a slim profile that is essential for modern, space-constrained micro-engineering designs.

03. High-Grade GCr15 Chrome Steel

Utilizing premium GCr15 Chrome Steel (SAE 52100) for both the rings and the rolling elements, the R155-ZZ is manufactured to P5-level precision. The advanced heat-treatment process ensures high load-bearing capacity, extreme hardness, and excellent dimensional stability even under continuous, high-RPM operation.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series R Series (Miniature Imperial / Inch)
Basic Designation R155
Suffix Options ZZ (Double Metal Shields)
Bore Diameter (d) 3.967 mm (5/32")
Outer Diameter (D) 7.938 mm (7.938 mm)
Width (B) 3.175 mm (1/8")
Material (Races & Balls) Chrome Steel (GCr15 / SAE 52100) or Stainless Steel (AISI 440C)
Precision Class Standard / P5 Grade Available
Cage Material Pressed Steel or Polyamide
Dynamic Load Rating (Cʳ) 0.380 kN (380 N)
Static Load Rating (C₀ʳ) 0.141 kN (141 N)
Limiting Speed (Grease) 45,000 r/min
Limiting Speed (Oil) 54,000 r/min
Weight (approx.) 0.0006 kg (0.6 grams)

Interchange Part Numbers

Universal cross-references for simplified global sourcing:

  • NMB: R-8532ZZ
  • SKF: R155-2Z
  • FAG: R155-2Z
  • NSK: R155ZZ
  • NTN: R155ZZ
  • Barden: R155SS
  • KOYO: R155ZZ

Design & Configuration

With 15 years of manufacturing excellence, Welink Bearing provides high-precision solutions tailored to modern industrial needs. The R155-ZZ is factory-lubricated with high-grade synthetic grease, ensuring smooth operation immediately upon installation. For specialized requirements—such as vacuum environments, extreme temperature shifts, or high-vibration scenarios—our technical team can provide custom clearance (C3) or alternative lubrication options to meet your exact specifications.

"Enhance your micro-designs with the R155-ZZ bearing—offering shielded reliability, precision imperial sizing, and high-velocity performance for demanding assemblies.”

Download Product Catalog (PDF)

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