Synertech Stock
Rotating shaft oil seals M
A seal ring, specifically a “rotary shaft seal type M,” is an industrial gasket designed to prevent fluid leaks and protect rotating components from external contaminants.
Product codes
Details
The M series rotary shaft seals, known on the market as metal-cased oil seals or Type M, are dynamic seals designed to ensure the retention of hydraulic oils and fluid lubricants. The profile features an exposed "L"-shaped outer metal reinforcement, precision-ground, and a dynamic elastomer lip preloaded by a garter spring. This configuration ensures absolute mechanical locking and high flatness within the housing.
Type M / WB Standard
Single dynamic sealing lip profile equipped with an internal garter spring and an exposed ground metal outer diameter.
Type M/DL
Double-lip variant, where applicable, equipped with an additional front dust lip without a spring, corresponding to the standardized WC profile, for protection against external contaminants.
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 | — |
Metal structure
Mineral hydraulic oils, fluid gear lubricating oils, mineral and synthetic greases, water and fluid emulsions.
Main features
Ground metal outer diameter
The outer steel surface is mechanically press-fitted into the housing with precise diametrical interference. The metal-to-metal fit ensures structural locking in the housing, reducing the risk of torsional micro-movements.
Constant radial load
The spring positioned behind the lip applies calibrated and continuous radial pressure to the rotating shaft diameter. It compensates for elastomer ageing, vibrations and minor misalignments, maintaining the dynamic sealing area.
Sealing edge
The main lip is finished with a precise, sharp geometric cut. The angle creates a hydrodynamic wedge that uses the surface tension of the oil film to limit leakage and provide self-lubrication of the running surface.
Advantages of the M profile
Torsional stability
The press-fitted metal casing eliminates axial movement and elastic rebound during installation and counteracts the risk of seal ejection caused by vibrations or mechanical shocks from the machine.
Liquid fluid sealing
The presence of the spring makes the seal suitable for very fluid, low-viscosity oils, maintaining correct alignment of the dynamic lip with respect to the axis of rotation.
Heat transfer
Direct metal-to-metal contact between the oil seal's outer casing and the housing promotes dissipation of the heat generated by friction between the dynamic lip and the shaft.
Typical applications
- Housings and bearing seats machined in cast iron or steel in industrial gearboxes and geared motors
- Crankshafts, camshafts, wheel hubs and differentials in the automotive and truck sectors
- Hydraulic pumps, centrifugal pumps, fans and positive displacement compressors
- Heavy-duty industrial electric motors and transmission shafts of machine tools
- Drive axles and rigid angle drives exposed to high mechanical loads in the agricultural sector
International standards
Construction dimensions, geometric tolerances and installation dimensions in compliance with DIN 3760 Form B and ISO 6194-1 Type 1C standards, corresponding to the universal WB profile.
Available configurations
Type M Standard
Traditional configuration suitable for general heavy-duty mechanical applications. It is ideally suited to stable housings machined in cast iron or steel, where it provides effective oil sealing at competitive cost.
Type M Premium
Specific configuration for high-speed shafts up to 35 m/s or operating at high temperatures in contact with aggressive synthetic oils. The use of stainless steel for the casing counteracts external oxidation, while the fluoroelastomer withstands special synthetic lubricants.
Market equivalents
| Manufacturer | Type M Standard - NBR | Type M Premium - FKM / Viton |
|---|---|---|
| Net Seals | Metal Oil Seal Series WB / M | Viton Metal Oil Seal Series WB / M FKM |
| Freudenberg (Simrit) | Simmerring® B / 827S Profile | Simmerring® B FKM Profile |
| Parker Prädifa | SB / B Profile | SB (FKM) Profile |
| Dichtomatik | WB Profile | WB FKM Profile |
| Kastas Sealing Technologies | K27 Profile | — |
| Corteco | Type M External Metal Oil Seal Series | — |
| SKF | — | Viton metal-cased seals (CRW1) |