The seal has to be able to cater for harmonic vibration, eccentricity and whip of the shaft. So what are the challenges with making a reliable crank seal?
One of the biggest tasks is selecting the right material. Providing an effective seal on a shaft running at high speeds means that the rubber material has to be extremely durable and flexible. The elastic modulus of the rubber is carefully chosen so as to create a sufficient contact force from the lip to the shaft.
Our YB crank seals are made from FPM rubber. This type of fluoroelastomer has exceptional resistance to chemicals and temperatures. FPM has a low compression set combined with remarkable ageing features. It is resistant to silicone and mineral oils and greases, petrol and diesel fuels, and chlorinated hydrocarbons, even when under a high vacuum.
In addition, our YB crank seals include small grooves in the lip that provide more compliance. On top of that, we have a garter spring that provides an additional constant compressive force.