Oil Seal Selection Guide｜High-Speed, High-Pressure Applications
Oil seals are critical components in industrial equipment, motors, gearboxes, and hydraulic systems. A poor seal choice can lead to oil leakage, contamination, excessive wear, and costly downtime. In this guide, we explain how to choose the right rotary shaft seal based on speed, pressure, material, and design—helping you select the optimal sealing solution for your application.
What Is a Oil Seal?
Oil seal (also known as a shaft seal or radial lip seal) is used to retain lubricants and exclude contaminants at the interface of a rotating shaft and a stationary housing.
Primary Functions:
Prevent lubricant leakage (oil, grease)
Protect against dust, dirt, and fluid ingress
Maintain internal pressure within the housing
Common applications include motors, pumps, gearboxes, compressors, and transmission systems.
Key Selection Criteria for Rotary Shaft Seals
Choosing the correct rotary seal involves evaluating operating conditions and design constraints. Below are the core factors to consider:
1. Speed & Pressure Ratings
| Operating Condition | Recommended Seal Type |
|---|---|
| High-speed rotation (>3000 RPM) | Low-friction lip design + PTFE variants |
| Pressurized system (>0.5 MPa) | Pressure-resistant spring-loaded seals |
2. Material Compatibility
| Material | Temp. Range | Key Features | Typical Use |
|---|---|---|---|
| NBR | -30°C to 100°C | Cost-effective, oil resistant | General machinery, gear oil |
| FKM (Viton®) | -20°C to 200°C | Heat and chemical resistance | Automotive, high-temp systems |
3. Seal Lip & Case Design
Single lip vs Double lip: Double-lip seals offer added dust protection.
Rubber-coated vs Metal outer case: Depends on housing surface finish and tolerance.
Why Choose CNL Oil Seals?
CNL specializes in high-precision rotary shaft seals designed for demanding industrial environments:
🔩 Spring-reinforced sealing lip for consistent contact pressure
🧪 Material options including NBR, FKM
🛠️ Custom sizes available for OEM and retrofit needs
🌐 Compliant with RoHS, REACH
👉 Browse Rotary Oil Seals Product Catalog
Real-World Applications
CNL oil seals are trusted by global OEMs and system integrators across industries:
Servo motors: Withstand high RPM and elevated temperatures
Gearboxes: Resist oil pressure and contamination
Common Questions
Q: Can oil seals handle vacuum or dry-running conditions?
A: Standard rubber seals are not recommended for vacuum. PTFE-based rotary seals are ideal for such environments.
Q: How do I know if a rotary seal is worn out?
A: Watch for oil leakage, hardened sealing lips, surface cracks, or shaft scoring. Regular inspection is key.
📞 Need Help Selecting a Oil Seal?
Whether you're building new equipment or replacing worn seals, CNL offers expert consultation, fast sampling, and global support.
👉 Contact Our Engineering Team | 📥 Download the Rotary Seals Catalog PDF