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MR Series
Home Deep Groove Ball Bearings MR Series

MR93-ZZ High-Speed Miniature Ball Bearing For RC Modeling | Double Shielded | 3x9x4 mm

MR93-ZZ High-Speed Miniature Ball Bearing For RC Modeling | Double Shielded | 3x9x4 mm

The MR93-ZZ is a precision-engineered micro ball bearing built specifically for applications requiring ultra-fast rotational speeds and minimal frictional resistance. With a compact 3x9x4 mm dimensional profile and dual non-contact metal shields (ZZ), this component effectively retains vital lubrication while blocking larger debris. Unlike rubber-sealed variants, the steel shields ensure zero mechanical drag, making this bearing the ultimate choice for high-RPM electric micro-motors, precision robotics, and specialized hobbyist equipment where maximizing kinetic efficiency is the top priority.

MR93-ZZ Deep Groove Ball Bearing Double Shielded | 3x9x4 mm | MR Series – High Speed & Low Friction

Engineered for smooth, high-velocity mechanics, this shielded miniature bearing excels in clean to moderately dusty environments. The ZZ configuration utilizes dual pressed steel closures that prevent the egress of internal grease without touching the inner ring. This low-torque design allows the MR93-ZZ to comfortably achieve speeds up to 43,000 RPM under grease and 50,000 RPM under oil lubrication, ensuring quiet operation, excellent heat dissipation, and extended service life for highly calibrated machinery.

MR93-ZZ High-Speed Miniature Ball Bearing For RC Modeling | Double Shielded | 3x9x4 mm

Comprehensive Applications

Tailored for designers and technical buyers requiring low-friction, 3mm bore components for compact assemblies:

Hobbycraft & RC Modeling
  • High-Performance RC Car Gearboxes and Wheels
  • Competitive Slot Car Motors
  • Premium Fishing Reel Spool Mechanisms
  • RC Helicopter Main Shafts
Micro-Electronics & Automation
  • Small Cooling Fans for IT Infrastructure
  • Hard Disk Drive Spindles
  • Precision Stepper Motors
  • Automated Vending Machine Coin Dispensers
Precision Tools & Medical Devices
  • High-Speed Dental Handpiece Turbines
  • Handheld Rotary Carving Tools
  • Precision Tattoo Machine Motors
  • Portable Diagnostic Optical Scanners
Small Household Mechanisms
  • Electric Shaver Drive Shafts
  • Compact Drones and Quadcopters
  • Automated Clockwork and Timers
  • Miniature Pump Impellers

Key Performance Features

01. Dual Pressed Steel Shields (ZZ)

Fitted with premium metallic shields on both sides, the MR93-ZZ offers excellent defense against particulate matter without sacrificing speed. This zero-contact shielding technology provides the lowest possible rotational torque, enabling extreme RPMs and preventing the overheating issues common in sealed bearings.

02. High-Purity GCr15 Chrome Steel

Constructed from industry-leading GCr15 (SAE 52100) Chrome Steel for all critical components—including the inner ring, outer ring, and rolling elements. The rigorous hardening process results in superior structural rigidity and wear resistance, maintaining critical P5/P6 precision tolerances over thousands of operational hours.

03. Ultra-Compact 3mm Bore Design

The 3x9x4 mm geometry is specifically scaled for micro-shaft integration. While weighing only 1.1 grams, it provides a stable 4mm raceway width capable of supporting dynamic loads over 570 N, making it indispensable for weight-restricted, high-efficiency motor layouts.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series MR Series (Miniature Metric)
Basic Designation MR93
Suffix ZZ (Dual Pressed Steel Shields)
Bore Diameter (d) 3 mm
Outer Diameter (D) 9 mm
Width (B) 4 mm
Material (Races & Balls) Chrome Steel (GCr15 / SAE 52100)
Precision Class Standard / P5 Grade Available
Shield Material Pressed Steel
Dynamic Load Rating (Cʳ) 0.574 kN (574 N)
Static Load Rating (C₀ʳ) 0.191 kN (191 N)
Limiting Speed (Grease) 43,000 r/min
Limiting Speed (Oil) 50,000 r/min
Weight (approx.) 0.0011 kg (1.1 grams)

Interchange Part Numbers

Common manufacturer equivalents widely recognized in the industrial market include:

  • SKF: MR93-2Z
  • NMBL-930ZZ
  • NSK: MR93ZZ
  • NTN: W673ZZA
  • FAG: MR93-2Z
  • KOYO: MR93-ZZ

Design & Configuration

The MR93-ZZ is the definitive solution for engineers demanding low frictional torque and sustained high-speed capabilities. Backed by Welink Bearing’s 15+ years of B2B manufacturing expertise, we offer customized solutions including specialized low-viscosity instrument oils for maximum RPM, and tailored internal radial clearances (C3/C4) to perfectly match your operating temperatures and shaft fits.

"Incorporate the MR93-ZZ double-shielded miniature bearing into your design to unlock unhindered rotational speed, enhanced thermal efficiency, and precision stability."

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