General information
The V-ring is a rubber-elastic shaft and bearing seal that is used for unpressurised applications. Due to its inherent preload, it sits firmly on a shaft with its base body and rotates with it. Dynamic sealing is achieved by its elastic sealing lip in the axial direction, e.g. against the face of a housing or bearing. The solid or liquid particles are propelled away from the sealing point by the rotary movement of the shaft and the resulting centrifugal force. Type VS is a version with an inclined back, which has the same lip geometry as the VA. The bevelled back of the base body, which gives it an approx. 50% greater installation length, also increases its inherent adhesion to the shaft. In addition, this back geometry offers an inexpensive design solution for securing the shaft axially and radially by means of a metal retaining ring or undercut of the shaft, which then has the bevelled back contour of the V-ring. To further improve the already good smooth running, a PTFE coating is possible, which enables friction to be reduced by approx. 40-50 %.
Medium
- NBR : Hydraulic oils based on mineral oil, air, water, emulsions
- FKM : synthetic oils and greases, acids, alkalis
- EPDM : hot air, light acids
Materials
Standard materials: NBR with a hardness of 65 Shore A and FKM with a hardness of 70 Shore A (available in EPDM with a hardness of 70 Shore A for special applications)
Advantages
- effective and inexpensive shaft seal
- low friction and long service life
- Sliding intensification for coating
- low design effort
- small installation spaces
- simple installation
- no high surface quality required on the shaft
- acts as a seal and dirt wiper
- suitable for high speeds
- slight angular deviations between shaft and mating surface possible ( ≤1°)
- can also be used as a static seal
Installation instructions
To ensure perfect function, the V-rings must be selected for the shaft diameters specified in the tables. This ensures a tight fit on the shaft due to the elastic internal preload. The axial installation dimensions of the values listed in the tables must also be observed. Up to a circumferential speed of 8 m/s, the V-rings do not require any additional securing. From 8 m/s to approx. 15 m/s, securing may be necessary to maintain exact alignment. This can be, for example, a shaft shoulder in the back of the V-ring, or a clamping band on the outer diameter of its base body, or a retaining ring that has the back contour of the V-ring. Ordinary surfaces without special requirements are sufficient for a tight fit on the shaft. The dynamic mating surface can be produced by precision turning, whereby there must be no radial, spiral grooves. The surface quality should be approx. Ra = 1.5 - 3 µm, Rmax = 5 - 10 µm, and Rz = 6.3 - 10 µm. The mating surface does not have to be hardened. However, a hardened surface is recommended for highly abrasive materials such as dirt or even sand and scale.
Field of application
Areas of application are in household electrical appliances and electric motors, mainly in small dimensions. Due to their easy handling, they are also used in mechanical engineering in water treatment, rolling mills and drying plants.
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