V-rings

Polyurethane (ACLA) (21)

V-ring Catalog Description Housing Materials Installation Installation dimensions

V-rings

V-rings are rotary seals that can perform numerous jobs in their function of sealing rotating shafts:

sealing against the penetration of dirt, dust, water or watery pollutants
combination with other sealing elements, e.g.the protection of a radial shaft sealing ring against external contamination
sealing against fat leaking from a housing

Advatages of V-rings:

diverse ﬁelds of application
no high requirements as regards the shaft and housing designs
low friction
high circumferential speeds are possible as a result of reduced friction
relatively insusceptible to coaxiality and radial eccentricity
long service life
easy installation

Structure and function

V-rings consist completely of elastomer. Their V-shaped proﬁle consists of a relatively solid retaining part and a ﬂ exible sealing lip that are „hinged“ together at the „V’s“ vertex. V-rings will be expanded while being installed, moved into the intended position on the shaft and cling to the shaft surface as a result of their internal stress. V-rings will rotate with the shaft and provide sealing in axialdirection against a counter face that is positioned verticallyto it. As a result of the diverse ﬁ elds of application for Vrings the counter face can be formed by:

the housing itself
a housing cover
a pressed-in metal sheet
the face of a roller bearing’s external ring
the metallic stiffetc

During the shaft’s standstill, the sealing lip clings to the counter face due to its initial contact pressure. Once the shaft starts rotating, the centrifugal force acts in radialdirection on the sealing lip, while the contact pressure drops with the increasing cir-cumferential speed.

The sealing lip starts to lift off the counter face from a circumfer-ential speed of approx. 15-20 m/s and the contact pressure drops to almost nil. The friction losses will increase with the rising circumferential speed almostlinearly up to approx. 10 m/s. The friction losses will decrease to 10 ... 12 m/s and drop almost to nil in the range between 15 and 20 m/s.

A V-ring‘s sealing eff ect is based on the contact between sealing lip and counter face and, additionally, on the entrifugal effect caused by the V-ring’s rotation. Once the sealing lip takes off at a very high circumferential speed, the V-ring will act as gap ring and centrifugal disk.