Sill Bearing
Sill Bearing
Engineered for extreme reliability, low vibration, and extended service life
The 6307 2RZ deep groove ball bearing represents a key geometric size within deep groove bearing engineering. Designed with boundary dimensions of 35mm inner diameter (bore), 80mm outer diameter, and a width of 21mm, it is engineered to handle substantial radial and light-to-moderate axial loads simultaneously. Under the SILL and NETB brands, these bearings are built using premium GCr15 high-carbon chromium bearing steel, known for its superior rolling fatigue strength and wear resistance.
What sets the "2RZ" configuration apart is the installation of dual-lip non-contact synthetic rubber seals on both sides. Unlike contact seals (2RS), which press directly against the inner ring and create friction that limits operational speed, the 2RZ design leaves a minuscule, precisely controlled gap between the rubber lip and the inner ring. This creates a labyrinth seal effect, protecting the bearing from dust and moisture while maintaining the low torque profile of a shielded metal bearing.
Technical reference details for mechanical design engineers and industrial buyers
| Dimensional Attribute | Value | Sealing & Precision Standards | Value / Status |
|---|---|---|---|
| Bore Diameter (d) | 35 mm | Sealing Type (2RZ) | Double non-contact NBR rubber seals |
| Outer Diameter (D) | 80 mm | Basic Dynamic Load Rating (Cr) | 33.5 kN |
| Width (B) | 21 mm | Basic Static Load Rating (C0r) | 19.2 kN |
| Chamfer Dimension (r min) | 1.5 mm | Limiting Speed (Grease) | 9,500 r/min |
| Material Code | GCr15 (SAE 52100 / 100Cr6) | Internal Clearance | C2, CN (Normal), C3, C4 |
| Weight | 0.46 kg (approx.) | Noise & Vibration Level | Z1V1, Z2V2, Z3V3 (Customized) |
Underpinning our 100% product acceptance rate commitment
Every batch of raw GCr15 high-carbon chromium bearing steel undergoes chemical compositions, non-metallic inclusions, and microstructure analysis via spectroscopy prior to wire drawing or forging.
Machinists run continuous in-line dimensional measurements on automated CNC turning, grinding, and super-finishing lines, detecting deviations before they can affect subsequent processes.
Completed raceways and sub-assemblies undergo 100% physical and structural scanning, including automated checking of internal radial clearance, noise, and vibration (Z3V3 criteria).
Using advanced Statistical Process Control (SPC) methods, our chief quality engineer extracts random samples from finalized packaging lines to evaluate batch tolerance distributions.
Before cargo release, every batch is checked for outer appearance, preservation oil application, rust protection, laser etching legibility, and structural pallet compliance.
Logistical leverage, rapid capacity expansion, and strategic coastal location
SILL BEARING FACTORY is strategically situated in the Hangzhou Bay New Zone. This location places the production center adjacent to the Hangzhou-Ningbo Expressway, the 329 State Line, and the Hangzhou-Ningbo Railway Line. More importantly, it offers direct access to the two largest marine shipping terminals in China: the Shanghai Port and the Ningbo Port. Cargo can reach local airports, including Hangzhou Xiaoshan Airport and Ningbo Lishe Airport, within approximately 90 minutes.
To support growing international demand, our new manufacturing plant, Anhui TOPB IMP.&EXP. Co., Ltd., is under construction. Once fully operational, this expansion will increase our annual production capacity by $20 million. This added capacity allows us to accept large-scale OEM orders while maintaining prompt lead times.
A look at our primary specialized mechanical bearing categories
Versatile, self-retaining bearings with deep groove raceways. Suitable for high speeds, they support both radial and axial loads in both directions with low friction and noise.
Featuring inner and outer rings with tapered raceways. Available in single, double, and four-row configurations designed to handle heavy combined radial and axial loads.
Engineered for high-speed systems, these bearings carry significant one-way axial loads. Larger contact angles increase their overall thrust load capability.
Designed to save space while providing high radial load capacity. Often paired with thrust bearings to handle combined forces in tight configurations.
Explore our most popular deep groove ball bearing product series
Where precision meets mechanical efficiency in global industries
For high-speed EV motors, fractional horsepower drives, and generators, the 6307 2RZ bearing provides low friction torque. This helps maintain high RPM levels without the heat buildup associated with contact rubber seals (2RS).
Used in high-load washing machine drums, drum shafts, and vacuum cleaner fans. The 2RZ seals help keep lubricant sealed inside the bearing while keeping ambient dust and moisture out, helping ensure quiet, long-term operation.
Withstands severe vibration and variable engine-bay temperatures. Installed in gearboxes and auxiliary shafts, GCr15 high-carbon chromium steel helps maintain structural stability under continuous load.
Critical for pumps and tractors operating in dusty fields. The non-contact synthetic rubber seals (2RZ) help keep abrasive dirt out of the internal raceways, reducing the risk of premature bearing failure.
How Sill Bearing is adapting to the next generation of industrial systems
Industrial systems are demanding longer service lives, higher rotational speeds, and lower overall energy consumption. SILL BEARING is continuously developing new material variants and sealing designs to meet these needs.
Our engineering roadmap includes implementing hybrid ceramic deep groove ball bearings, using silicon nitride (Si3N4) balls with GCr15 steel rings. These hybrid bearings are designed to provide electrical insulation, lower weight, and higher limiting speeds for advanced electric vehicle motors.
Additionally, we are testing high-temperature synthetic lubricants and fluorinated rubber seal compounds to extend the operating range of our 2RZ bearings beyond 150°C, supporting demanding industrial applications.
Answers to common engineering and sourcing questions
The difference lies in the design of the seal. The 6307 2RS uses a contact rubber seal where the seal lip touches the inner ring. This provides good sealing but increases friction and heat, limiting speed. The 6307 2RZ uses a non-contact synthetic rubber seal that leaves a small gap. This reduces friction and allows for higher speeds, similar to a shielded bearing, while still protecting against dust.
GCr15 (equivalent to SAE 52100 or 100Cr6) is a standard alloy steel for precision rolling element bearings. It contains chromium and high carbon, which, after heat treatment, provides high hardness (typically HRC 60-65), dimensional stability, and wear resistance, helping to extend operating life.
We produce bearings with normal clearance (CN), which is suitable for standard operating temperatures and press fits. We also offer C3 and C4 clearances for applications with high temperatures, high speeds, or heavy press fits where thermal expansion must be accommodated.
Yes. We offer OEM production under our SILL and NETB brands, as well as customized configurations. We can adjust dynamic load ratings, noise levels (up to Z3V3), clearances, and grease fills to suit specific customer applications.
Supporting diverse industrial, automotive, and linear motion systems
