Oil Seal VG - Rotary Shaft Seal

Sealing Construction & How It Works

During operation time the sealing lip maintains a stable and controlled contact with the rotating shaft. Because the VG oil seal is designed for pressure less media, it performs best in combination with lubricants which stay within the thermal and chemical limits of the material. With correct alignment, lubrication and installation, the VG oil seal provides consistent performance and long service life in demanding mechanical environments.

Applications

The VG oil seal is intended for supportive or secondary sealing tasks where pressure is absent, and lubrication must be reliably maintained. It is frequently used in general machine and equipment construction, particularly in assemblies where a compact sealing solution is necessary. Because the elastomer-coated OD compensates for rough housings, split housings and thermally active structures, the VG type is especially well suited to light-metal housings commonly found in modern mechanical systems.

In drive technology, the VG seal performs well in grease-lubricated components such as small gear mechanisms, bearing housings and auxiliary drives. Its low-friction behavior also makes it a practical choice for electric motors, where efficient running and controlled heat development are critical. The VG type represents a dependable sealing option wherever a minimalistic, low-wear and space-efficient solution is required.

Materials

The standard VG oil seal is made of green NBR 70. This is a robust elastomer which is suitable for mineral oils, grease and many synthetic lubricants. The internal reinforcement ring is made of sheet steel according to DIN EN 10139, ensuring dimensional stability during installation and operation.

For applications requiring enhanced thermal, chemical or mechanical resistance, the VG rotary shaft seal is also available in several special elastomers. This includes: FKM for applications with high temperatures or chemically aggressive oils, silicones for extremely low temperature environments, ACM for applications with exposure to motor oils, HNBR for heavy mechanical loads and raised temperatures, CR for situations with exposure to weather and ozone, and EPDM for environments with water, steam or glycol-based liquids.

Below is an overview of the material options and their performance characteristics.

Material Overview Table

Comparison With KG and VC Oil Seal Types

Within the same product family, the oil seal VG, the oil seal KG and VC oil seals share the same basic springless lip design, but differ in how they interact with the housing and the environment. The VG oil seal type uses a ribbed elastomer-coated outer diameter without a dust lip, making it ideal for grease and oil sealing in clean, pressureless applications where low friction, compact design and good compensation for housing roughness or thermal expansion are important. The oil seal VC type has the same sealing lip geometry as the oil seal VG, but features a smooth elastomer outer diameter instead of a ribbed one. This makes the VC oil seals suitable for housings with more consistent surface quality and tighter machining, where less deformation of the OD is required. The rotary shaft seal KG type is, in essence, a VG seal with an additional dust lip: it keeps the same ribbed elastomer OD and springless sealing lip, but adds extra protection against contamination from the outside. As a result, the VG oil seal is typically chosen for internal, cleaner environments with minimal external dirt, KG for applications where dust or particles are present, and VC where a smooth elastomer OD is preferred due to housing design or manufacturing conditions.

Selecting the Right Seal

Choosing the right VG oil seal requires attention to both material properties and mechanical tolerances. The oil seal VG can’t be used in the hydraulic of pneumatic systems because it’s designed for pressure less systems. Its maximum allowable circumferential speed is 6 m/s, and the standard NBR version operates reliably between –40°C and +100°C. When synthetic lubricants are used for the first time, the compatibility must be verified through laboratory of practical testing. In this case the temperature can’t reach higher than 80°C. The performance of the VG oil seal depends strongly on the correct shaft- and housing conditions. The shaft must match ISO h11 tolerances, be hardened to at least 45 HRC and feature a torsion-free surface with a roughness between Ra 0.2 and 0.8 μm. The housing must match the ISO H8 tolerance and may have a rougher surface, as the ribbed elastomer outer diameter compensates for irregularities. Proper installation is essential for long-term performance, and the manufacturer’s installation guidelines should always be followed to avoid damage during assembly.

FAQ – VG Oil Seal