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German634 bearing
Deep groove ball bearing available in Open, ZZ metal-shielded, and 2RS rubber-sealed configurations. 4mm bore, 16mm OD, 5mm width. ABEC-3 precision, 1.73kN dynamic load capacity.
634 Deep Groove Ball Bearing 4x16x5mm
The 634 bearing is the widest-OD option in the 4mm-bore deep groove ball bearing series. At 16mm outside diameter with a 5mm wide ring, the 634 bearing delivers 1.73kN dynamic load capacity, roughly 50 percent more than the 624 bearing (4x13x5mm). Supplied in three configurations to match the operating environment: Open for oil-bath or grease-packed housings where the assembly provides contamination protection, ZZ for non-contact metal shields that preserve full 44,000 RPM speed in dry and dusty settings, and 2RS for contact rubber seals that block moisture and fine particles in wet or outdoor applications. All three share identical ring geometry, GCr15 chrome steel material, and ABEC-3 precision tolerance.
Key Specifications
- Dimensions: 4mm bore (d) x 16mm outside diameter (D) x 5mm width (B)
- Configuration: Available in Open, ZZ (metal-shielded), and 2RS (rubber-sealed)
- Load Ratings: 1.73kN dynamic (Cr), 0.68kN static (C0r)
- Speed Ratings: 44,000 RPM (Open / ZZ), 35,000 RPM (2RS)
- Material and Precision: GCr15 chrome steel (AISI 52100 equivalent), stamped steel cage, lithium grease, ABEC-3 tolerance
For any inquiries, please contact with our Supporting Team at sales@yuanhecd.com.
| Model | 634 ZZ |
| Type | Open / Shielded / Sealed |
| Bore Dia (d) | 4 mm |
| Outside Dia (D) | 16 mm |
| Width (B) | 5 mm |
| ABEC Tolerance | ABEC-3 |
| Dynamic Load Capacity (kN) | 1.73kN |
| Static Load Capacity (kN) | 0.68kN |
| Max. RPM | 44,000RPM (Open/ZZ) / 35,000RPM (2RS) |
| Temp. Range (℃) | -40~120℃ |
| Material | GCr15 (AISI 52100) |
| Shield/Seal | SPCC (ZZ) / NBR+SPCC (2RS) |
| Lubrication | Grease |
Bore (d)
4 mm
OD (D)
16 mm
Width (B)
5 mm
Dyn. Load
1.73 kN
Max RPM
44,000
Precision
ABEC-3
Configuration Options
The 634 bearing is supplied in three configurations to match the operating environment. All three share identical ring geometry, GCr15 chrome steel material, and ABEC-3 precision.
Open 634 bearing carries no shields or seals, reaching the full 44,000 RPM with grease or oil supplied by the housing. Use this configuration when the bearing runs inside a sealed gearbox, oil-bath enclosure, or grease-packed cavity where the assembly itself blocks contamination.
634 ZZ bearing adds non-contact pressed steel shields (SPCC) on both sides. The shield-to-inner-ring gap adds no measurable friction, so the ZZ configuration retains the full 44,000 RPM. Metal shields deflect coarse dust, lint, and debris. Choose ZZ for dry environments: encoder housings, instrument assemblies, and motors where contamination risk is limited to airborne particles.
634 2RS bearing uses nitrile rubber (NBR) contact seals that press against the inner ring shoulder, creating a positive barrier against moisture spray, fine dust, and metal particles. Seal friction limits speed to 35,000 RPM. The NBR compound resists swelling in water-glycol mixtures and light oils. Choose 2RS for wet, dusty, or outdoor environments: pump shafts, garden machinery, and agricultural equipment. All three configurations are factory-filled with lithium-base grease within the -40 to 120 degrees C range.
Performance
Within the 4mm-bore deep groove ball bearing series, the 634 bearing holds the largest-OD position at 16mm. The 624 bearing (4x13x5mm) delivers 1.15kN dynamic load, a 34 percent reduction. The 604 bearing (4x12x4mm) drops to 0.96kN. The 634 bearing earns its load advantage from the 6mm radial wall thickness, providing more material under the raceway to distribute contact stress. Deep groove geometry gives axial capacity at roughly 25 percent of the radial rating, approximately 0.43kN. Chrome steel (GCr15) rings and balls, stamped steel cage. Manufactured to precision bearing standards with ABEC-3 tolerance. Bore tolerance at ABEC-3 is plus 0 minus 8 microns.
OEM and Customization
Custom clearance (C2, CN, C3) is available for production volumes. C2 reduced clearance for encoder applications, C3 for press-fit motor mounting. Cage upgrades: glass-fibre reinforced polyamide (PA66-GF25) for reduced noise, brass for temperatures above 150 degrees C. 440C stainless steel rings and balls for medical and food-processing equipment (load rating reduces to ~1.38kN). Seal upgrades for 2RS: Viton (FKM) to 200 degrees C, silicone for below minus 40 degrees C. Custom grease: low-temperature ester, water-resistant calcium sulfonate, PFPE for cleanroom. Submit your custom bearing specification for a quote.
Applications
●Encoder and resolver modules (ZZ)
●Dental and surgical handpiece spindles (ZZ)
●Sealed gearbox shafts (Open)
●Oil-bath spindle assemblies (Open)
●Miniature peristaltic pump heads (2RS)
●Compact lab stirring mechanisms (2RS)
●Optical chopper wheels (ZZ)
●Agricultural sensor bearings (2RS)
FAQ
How do I choose between Open, ZZ, and 2RS for a 634 bearing? +
Choose the Open 634 bearing when the bearing runs inside a sealed gearbox or oil-bath housing where the enclosure provides contamination protection. Open bearings reach 44,000 RPM and require external lubrication. Choose the 634 ZZ bearing for dry environments with airborne dust or lint; non-contact metal shields add no friction and retain the full 44,000 RPM. Choose the 634 2RS bearing for wet, dusty, or outdoor environments; rubber contact seals block moisture and fine particles at the cost of a 35,000 RPM speed limit. All three share the same 1.73kN load rating and ABEC-3 precision.
How does the 634 bearing compare to the 624 bearing? +
The 634 bearing (4x16x5mm) has a 3mm larger OD than the 624 bearing (4x13x5mm). The extra 1.5mm of radial wall thickness gives the 634 bearing 1.73kN dynamic load versus 1.15kN for the 624 bearing, a 50 percent increase. Both fit a 4mm shaft. Choose the 634 bearing when the housing can accommodate 16mm and higher load capacity is needed. Choose the 624 bearing when the housing is limited to 13mm OD.
What is the difference between a 634 bearing and a 684 bearing? +
Both bearings fit a 4mm shaft but serve opposite design constraints. The 634 bearing (4x16x5mm) maximizes load capacity at 1.73kN with a 16mm OD. The 684 bearing (4x9x4mm) minimizes radial space at 0.54kN with a 9mm OD. The 634 bearing is 5mm wide versus 4mm for the 684 bearing. Choose the 634 bearing for high-load 4mm-shaft applications. Choose the 684 bearing when radial space is the primary constraint.
Can the 634 bearing operate at temperatures below minus 40 degrees C? +
Standard 634 bearings with lithium grease are rated to minus 40 degrees C. Below this, grease thickens and starting torque increases. For minus 50 to minus 70 degrees C, specify low-temperature ester grease. Below minus 70 degrees C, GCr15 steel loses dimensional stability. For cryogenic use, contact Yuanhe about alternative materials and dry film lubrication.
