Skeleton Oil Seal Lip Design and Spring Structure Guide

Many people struggle when selecting skeleton oil seals: what’s important in
lip design? What’s the difference between spring-loaded and non-spring
seals? Based on practical experience, here’s an overview:

Lip Design Considerations

The lip of an oil seal is like the “gap at the door”—whether it can block
oil and dust depends entirely on it.

· Single lip: Simple and straightforward, suitable for low-pressure
environments, providing basic sealing.

· Double lip: In addition to the main sealing lip, there is an auxiliary
dust lip, often used in more demanding conditions such as engines and
hydraulic systems.

· Material selection is also critical:

NBR is oil-resistant.

FKM is heat-resistant.

PTFE is corrosion-resistant, has low friction, and is suitable for high-
speed applications. Choosing the right material for the operating
environment makes a significant difference in performance.

Spring-Loaded vs. Non-Spring Oil Seals

· Spring-loaded oil seals: The spring continuously applies pressure to the
lip. Even if the shaft wears slightly or temperature fluctuates, the seal
remains effective. Commonly used in high-speed, high-vibration, and
variable-temperature equipment such as engine crankshafts.

· Non-spring oil seals: Rely on the elasticity of the rubber itself for
sealing. They have a simpler structure, lower friction, and reduced cost.
Suitable for low-speed, dust-prevention, or less demanding leakage
requirements, such as fan end covers or agricultural machinery.

How to Choose Skeleton Oil Seals?

In short:

· For complex operating conditions with significant temperature and
pressure fluctuations, spring-loaded oil seals are the safer choice.

· For general dust prevention, low-speed, and light-load applications, non-
spring oil seals are sufficient and cost-effective.

Recommendation

When selecting oil seals, don’t just look at the price. First, clarify the
operating conditions: speed, temperature, pressure, and medium. Then match
the material and structure accordingly. This way, you can avoid the
embarrassment of “buying cheap but ending up with oil leaks and rework.”

Minimum Order: 1000 pieces

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