Secondary Lip: Pressure Rating 0-0.5 bar

Component Specifications

Definition

The Secondary Lip is a critical sealing component in propeller shaft seal assemblies, designed as a redundant sealing barrier that operates in conjunction with the primary lip. It prevents lubricant leakage from the gearbox or transmission while blocking external contaminants like water, dust, and debris from entering the system. This component typically features a flexible geometry that maintains consistent contact pressure against the rotating shaft surface under varying operational conditions.

Working Principle

The Secondary Lip functions through elastohydrodynamic lubrication principles, creating a thin fluid film between its contact surface and the rotating shaft. Its flexible design allows it to maintain sealing integrity despite shaft eccentricity, thermal expansion, and wear. It operates as a secondary barrier that activates when the primary seal experiences temporary pressure fluctuations or minor damage, ensuring continuous protection.

Materials

Nitrile rubber (NBR) for general applications, Fluorocarbon (FKM/Viton) for high-temperature resistance, Polyacrylate (ACM) for oil resistance, or Silicone (VMQ) for extreme temperature ranges. Material hardness typically ranges from 70-90 Shore A.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Shaft Speed	Up to 15 m/s
Spring Load	Optional depending on design
Pressure Rating	0-0.5 bar
Lip Interference	0.3-0.8 mm
Operating Temperature	-40°C to +150°C

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 6194, DIN 3760, SAE J946

Parent Products

This component is used in the following industrial products

Propeller Shaft Seal

A sealing component that prevents water ingress and lubricant leakage around the propeller shaft where it exits the steering pod.

View Product Details

Engineering Analysis

Risks & Mitigation

Lip hardening due to thermal degradation
Abrasive wear from contaminated environments
Chemical incompatibility with specific lubricants
Installation damage during assembly

FMEA Triads

Trigger: Excessive shaft runout or misalignment
Failure: Uneven lip wear leading to leakage paths
Mitigation: Implement proper shaft alignment procedures and specify maximum allowable runout tolerances

Trigger: Chemical incompatibility with operating fluids
Failure: Material swelling, hardening, or degradation
Mitigation: Conduct material compatibility testing with specific lubricants and environmental contaminants

Trigger: Incorrect installation angle or damage during assembly
Failure: Immediate leakage or reduced service life
Mitigation: Use proper installation tools and provide comprehensive assembly training

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Lip dimensions ±0.15 mm, Hardness ±5 Shore A

Test Method

ISO 6194-1 for radial lip seals, ASTM D1414 for compression set, ASTM D2240 for hardness testing

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Secondary Lip

Manufacturer profiles associated with Secondary Lip.

Sourcing Secondary Lip from China?

Tell us your specification and target quantity — we will match it against manufacturer records and come back with the factories that fit.

Request manufacturers We manufacture this

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

Related Components

Clutch Disc

A clutch disc is a friction component in clutch-brake systems that engages and disengages power transmission between rotating shafts.

Synchronizers

Synchronizers are precision components in manual transmissions that enable smooth gear shifting by equalizing rotational speeds between gears and shafts.

Brake Disc (Rotor)

A rotating disc in disc brake systems that creates friction with brake pads to slow or stop vehicle motion.

Main Bearing Journals

Main bearing journals are precision-machined cylindrical surfaces on a crankshaft that rotate within main bearings to support rotational motion in internal combustion engines.

Frequently Asked Questions

What is the main purpose of a secondary lip in shaft seals?

The secondary lip provides redundant sealing protection by preventing lubricant leakage and blocking external contaminants when the primary seal is compromised or during pressure variations.

How does the secondary lip differ from the primary sealing lip?

The secondary lip typically has less aggressive contact pressure and is designed primarily for contaminant exclusion rather than high-pressure fluid retention, though it provides backup sealing capability.

What materials are commonly used for secondary lips in automotive applications?

Nitrile rubber (NBR) is most common for general use, while fluorocarbon (FKM) is preferred for high-temperature environments, and polyacrylate (ACM) offers superior oil resistance.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Secondary Lip