Hasse & Wrede - Viscous Torsional Vibration Dampers

Hasse & Wrede (H&W) is the world's largest supplier of viscous torsional vibration dampers, developing and manufacturing torsional vibration dampers for various applications such as ship engines and passenger cars.

Many diesel engines (like those made by Deutz, MWM, MAK, MAN, MAN / B&W, MTU, SKL, Sulzer and Caterpillar, for example) are equipped with one or two Hasse & Wrede viscous torsional vibration dampers attached to the front end of the crankshaft and camshaft.

A TORSIONAL VIBRATION DAMPING EFFECT

The purpose of the vibration damper is to reduce the torsional vibrations in the crankshaft and to keep the material stresses within permissible limits by eliminating the risk of failure.

The visco-damper provides the necessary torsional vibration damping effect by resilient, damped coupling of the secondary mass (inertia ring) to primary mass (housing).

When the crankshaft rotates uniformly, without any applied torsional vibration, the inertia ring in the housing also rotates without any slippage occurring. However, when vibration amplitudes are superimposed, a relative movement is caused to take place between housing and inertia ring. The resultant forces generate alternating stresses in the silicone film. So the sum of these stresses over the entire gap surface between inertia ring and housing results in a damping action.

EXACT PREDICTABLE ENGINE AND DAMPER BEHAVIOUR

The advantages of Hasse & Wrede's visco-dampers include:

• Exact predictable engine and damper behaviour using Hasse & Wrede's calculating method for torsional vibration analysis
• Specific damper tuning according to customer requirements
• Damping on a broad frequency range
• Provides noise reduction
• Temperature-stabilised silicone oil that allows the damper to operate at a higher temperature than other damper systems in its application range
• Compact size, with integrated pulley and hub solution options
• Extended service life
• Flexible service solutions

MAINTENANCE / REMANUFACTURE OF VISCO-DAMPERS

The damper itself requires no routine maintenance, but the tightness of the bolts securing it to the crankshaft should be checked periodically in accordance with the engine manufacturer's recommendations.

Severe mechanical damage to the damper or degradation of the viscous fluid may lead to excessive strain of the crankshaft and transmission components, eventually leading to crankshaft failure. This is why we recommend a silicone oil analysis at regular intervals.

Taking an silicone oil sample allows us to analyse the damper’s state of wear and provides the data base for recommendations how to proceed with it. Options include:

• Confirming operation until end of lifetime
• Recommending service at Hasse & Wrede reconditioning centre
• Recommending service of damper on site / onboard

Dampers with bolted or welded covers can be overhauled. The service provided by H&W is remanufacture of the visco-damper to give it a new lease of life. This is achieved using the established H&W state-of-the-art technology.

Other brands also can be reconditioned by H&W.