684 / 684ZZ / 684-2RS Ultra-Miniature Ball Bearing (4mm x 9mm x 2.5mm / 4mm)

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684 / 684ZZ / 684-2RS Ultra-Miniature Ball Bearing (4mm x 9mm x 2.5mm / 4mm)

Model: 684 / 684ZZ / 684-2RS

Delivers high torque density in a compact diameter design
Precision gear structure ensures smooth & ultra-low noise operation
Wide output speed range to meet versatile industrial needs
Fully customizable gear ratios, shaft dimensions, and wire leads
Heavy-duty industrial grade quality with long operational lifespan

Product Highlights

Ultra-miniature metric dimensions (4mm ID x 9mm OD) suited for compact mechanical assemblies
Available in open type (2.5mm width) and shielded / sealed type (4mm width)
High-carbon chromium bearing steel (GCr15) providing superior surface hardness and fatigue resistance
Capable of high rotational speeds up to 63,000 RPM under oil lubrication
Precision ground raceways ensuring sub-micron concentricity, low vibration, and quiet rotation
Ultra-low starting torque optimizing energy efficiency for battery-powered micro drives
ABEC-3 / ABEC-5 precision rating guaranteeing reliable rotational accuracy under load
Full RoHS and REACH environmental compliance across all manufacturing processes

Applications

> Micro Motors & Cooling Fans
> Precision Testing Instruments
> Medical Diagnostic & Imaging Devices
> Automotive Steering & Chassis Systems
> Fitness & High-End Sports Gear
> Textile & Garment Machinery
> High-Precision Spindles & CNC Units
> Material Handling & Conveyor Rollers
> Optical Encoders & Gimbal Systems

Technical Specifications

Parameters	Specifications
Inner Diameter	4mm
Outer Diameter	9mm
Width	4mm
Precision Rating	P0
Clearance	C0
Sealing Type	ZZ
Number of Row	Single Row
Material	chrome steel
Grease RPM Limit	2000 RPM
Lubrication	Grease
Size	494MM
Certificate	ISO9001
Weight	0.01(kg)

Why Choose Us

Factory Manufacturing Capabilities

Modern precision workshop, advanced CNC automated machining centers, and 100% full-inspection assembly lines.

International Certifications

Verified compliance with global standards, supporting smooth customs clearance and regulatory approvals across North America and Europe.