Synertech Stock
Rotating shaft oil seals KAS-4
A **KAS-4 rotary shaft seal** is a specific type of dynamic seal used to prevent fluid leakage and contamination from external agents in rotating shafts, such as those in pumps and motors.
Product codes
Details
The KAS-4 series rotary shaft seals are high-performance double-lip dynamic seals designed for the retention of fluid lubricating oils and the simultaneous exclusion of severe external contaminants. The profile features a main lip preloaded by a garter spring and a geometrically optimized auxiliary outer dust lip. The rubber-covered outer casing ensures static sealing within the mechanical housing.
KAS-4 Standard
Double-lip profile, with a spring-loaded main sealing lip and an asymmetric dust lip without a spring, a completely smooth elastomer outer diameter and an internal "L"-shaped metal reinforcement.
KAS-4 Special
Variant with modified compounds or spring preload for applications operating under conditions of high eccentricity (run-out) of the rotating shaft.
Materials and operating conditions
| Material / Compound | Peripheral speed | Temperature | Max pressure |
|---|---|---|---|
| NBR Nitrile rubber 70 / 80 ShA |
Up to 12.0 m/s Up to 0.5 m/s in low-speed applications |
−30 / +100 °C | 0.05 MPa Standard atmospheric pressure |
| FKM Fluoroelastomer / Viton |
Up to 35.0 m/s | −20 / +200 °C | — |
Internal structure
Mineral hydraulic oils, fluid gear lubricants, mineral and synthetic greases, water, mud and abrasive or silica-based dust.
Main features
Optimized dust lip
The outer auxiliary lip features a more pronounced axial relief angle and high flexibility. Its special geometry shields and centrifugally expels mud, sand and fine dust, preventing them from reaching the internal spring.
Grease cavity
The geometric space between the main sealing lip and the protective lip acts as a pre-lubrication chamber. Filled with grease during installation, it lubricates the outer lip and traps abrasive micro-contaminants.
Smooth rubber-covered outer casing
The full elastomer coating ensures static sealing against the housing, compensating for structural thermal expansion and tolerating minor surface roughness or light machining marks in the groove.
Advantages of the KAS-4 profile
Superior mechanical protection
The system isolates the internal transmission components from external contaminants, protecting the primary sealing lip and reducing the risk of premature scoring on the metal shaft.
Hydrodynamic radial load
The internal garter spring maintains calibrated and constant radial pressure on the shaft, compensating for rotational vibrations and thermal stiffening of the rubber over time.
Housing-friendly installation
The rubber-covered outer casing reduces the force required for press-fitting into the housing and limits the risk of scratches or deformation in seats made from soft metals such as aluminium.
Typical applications
- Wheel hubs, drive axles and differentials in the automotive, truck and motorcycle sectors exposed to severe contamination
- Transmissions, power take-offs (PTO) and speed reducers for agricultural machinery
- Gearboxes, geared motors and hydraulic pumps operating outdoors or in dusty industrial environments
- Cylinders and rotary actuators for construction machinery, light earthmoving equipment and special vehicles
- Gearboxes for lifting and logistics handling systems exposed to continuous weather conditions
International standards
Construction dimensions, geometric tolerances and installation dimensions in compliance with DIN 3760 Form AS and ISO 6194-1 Type 2 standards, corresponding to the standardized high-performance WAS / TC / AS / GP series.
Available configurations
KAS-4 Standard
Configuration used in general mechanical engineering and standard agricultural replacement parts. Suitable for protection against dust and moisture when used with conventional mineral oils at medium temperatures.
KAS-4 Premium
Specific configuration for shafts operating at high rotational speeds, up to 35 m/s, or subject to significant cyclic temperature fluctuations. The fluoroelastomer provides greater resistance to synthetic lubricants and frictional heat.
Market equivalents
| Manufacturer | KAS-4 Standard - NBR | KAS-4 Premium - FKM / Viton |
|---|---|---|
| Net Seals | Oil Seal Series with Dust Lip GP / WAS / TC | Viton Oil Seal Series WAS / TC / GP FKM |
| Freudenberg (Simrit) | Simmerring® BASL / 829N Profile | Simmerring® BASL FKM Profile |
| Kastas Sealing Technologies | K28 / K30 Profile | — |
| Parker Prädifa | OSHAL / TC Profile | OSHAL (FKM) Profile |
| Dichtomatik | WAS Profile | WAS FKM Profile |
| Corteco | KAS-4 Oil Seal Series with Dust Lip | — |
| SKF | — | Viton rubber-covered seals with auxiliary lip (HMSA10) |