Isolated – Vibration Systems (Seals)

In vehicle and engine design, control of Noise, Vibration and Harshness (NVH) minimizes the transfer of undesirable engine noises into the passenger compartment. In today’s competitive market, proper NVH control is a consumer expectation in virtually all passenger vehicles. One method frequently used to minimize engine noise is to isolate covers from contact with the engine by using elastomer seals and grommets.

With excellent vibration damping properties, many elastomers can reduce vibration transmission from one rigid component to another. However, eliminating hard contact changes how seal compression is controlled. Rather than using a hard contact stop, seals are compressed until seal and grommet loads are balanced when fasteners are installed.

If the force balance is incorrect, seal and/or grommet compression will not be optimum, resulting in increased passenger cabin noise.

If seal or grommet compression is too low, reduced seal pressure may lead to leaks. If compression is too high, stress may exceed elastomer capabilities, resulting in damage and leaks.

With a state-of-the-art test lab to characterize material properties, Parker Engineered Seals Division uses Finite Element Analysis (FEA) to design and optimize critical elastomer components in an isolated system.

FEA’s are performed at tolerance limits for seals, grommets and mating components. By comparing force versus compression curves at tolerance extremes, a load balance can be achieved, providing proper seal compression under all tolerance conditions.

Above graph shows seal and grommet loads versus cover position for all seal, grommet and mating component tolerance conditions. Curve intersections indicate possible cover positions.

Isolated sealing systems can be employed to reduce NVH in many heavy duty, automotive and small engines. This seal analysis technology can also be used in other types of devices which generate structure borne NVH and would benefit from isolation.
Parker’s Engineered Seals Division, headquartered in Syracuse, Indiana, welcomes your toughest sealing challenges.