Synertech Stock
Grease seals MSM
The MSM type is a sealing ring with an external metallic support, either ground or calibrated, without a spring. It is designed for applications that require rigidity and strength, especially under heavy-duty conditions and large misalignments at high speeds.
Product codes
Details
The MSM series grease seals are rotary shaft seals designed for the retention of high-viscosity lubricating greases in applications with limited axial space. The profile features an exposed "L"-shaped outer metal casing, precision-ground, and a flexible springless elastomer dynamic lip. This configuration provides a rigid fit within the housing and high mechanical stability.
MSM Standard
Springless profile with an exposed ground metal outer diameter and a single flexible dynamic sealing lip facing inward.
MSM Mirrored
Variant suitable for installation in pairs, back-to-back, to provide physical separation between two areas lubricated with different greases.
Materials and operating conditions
| Material / Compound | Peripheral speed | Temperature | Max pressure |
|---|---|---|---|
| NBR Nitrile rubber 70 / 80 ShA |
Up to 6.0 m/s | −30 / +100 °C | Atmospheric No pressure |
| FKM Fluoroelastomer / Viton |
Up to 15.0 m/s | −20 / +200 °C | Atmospheric No pressure |
Outer casing
Mineral and synthetic lubricating greases, NLGI classes from 00 to 3, high-viscosity lubricating oils, environmental dust and trace moisture.
Main features
Ground metal outer surface
The exposed steel outer surface is mechanically press-fitted into the housing with precise diametrical interference. The metal-to-metal fit ensures high rigidity and stability within the housing.
Low-friction springless lip
The lip relies exclusively on the radial elastic interference of the vulcanized rubber against the shaft diameter. The absence of a spring reduces radial load and frictional heat generation.
Ultra-thin axial profile
Eliminating the space required for a garter spring reduces the axial dimensions of the seal, making it suitable for particularly compact housings.
Advantages of the MSM profile
Torsional stability
The metal casing press-fitted into the housing counteracts axial movements, elastic rebound during installation and possible displacement caused by vibrations or mechanical stresses.
Reduced breakaway torque
The absence of a spring reduces the power absorbed by friction during shaft start-up compared with a conventional spring-loaded oil seal.
Alignment precision
The rigid steel-to-steel press fit promotes correct alignment of the dynamic lip with the shaft's axis of rotation and uniform contact during operation.
Typical applications
- Grease-lubricated bearing supports and housings with precision steel or cast-iron casings
- Wheel hubs and oscillating joints for agricultural machinery, trailers and hydraulic arms
- Transmission shafts for small geared motors, portable power tools and gear pumps
- Mechanical joints and rotary couplings in automation and light robotics applications
- Cardan shafts and small transmission components in the automotive and motorcycle sectors
International standards
Construction dimensions, geometric tolerances and installation dimensions in compliance with international standards for springless metal radial shaft seals: ISO 6194-1 Type 4C or DIN 3760 Form H.
Available configurations
MSM Standard
Traditional configuration for general mechanical applications, suitable for stable housings machined from cast iron or steel and for grease retention at moderate temperatures.
MSM Premium
Configuration for applications with high peripheral speeds, up to 15 m/s, or subject to high temperatures. The stainless steel casing improves resistance to oxidation in humid environments, while the fluoroelastomer is suitable for more aggressive synthetic lubricants.
Market equivalents
| Manufacturer | MSM Standard - NBR | MSM Premium - FKM / Viton |
|---|---|---|
| Net Seals | Springless Metal Oil Seal Series MSM / B-G | Viton Metal Oil Seal Series MSM FKM |
| Freudenberg (Simrit) | Simmerring® B Profile / Springless Metal | B FKM Springless Profile |
| Trelleborg Sealing Solutions | Type B Metal Cased Radial Profile | Type B Metal Cased Viton Profile |
| Dichtomatik | WB-G Profile | WB-G FKM Profile |
| Corteco | External Metal Grease Seal Series (NBR) | Metal Grease Seal Series FKM |
| SKF | Springless Metal Radial Shaft Seals | — |