Engine isolation is an important design consideration because of the problems that may arise if proper steps aren't taken to control and manage vibration. Vibration is produced as a result of the transfer of energy when rotating machinery is mounted to a support structure. This vibration may affect the overall performance of the equipment and potentially damage its longevity. A good vibration isolation system works in two directions. It can keep vibration produced by a source such as an engine from being transmitted to the frame; and it can keep vibration in a system from being transmitted to a sensitive piece of electronics or even a human.
A properly designed engine isolation system can improve a vehicle's NVH (noise, vibration, and harshness), which is a subjective rating expressed by the driver on the quality of the driving experience in those three areas. Truck companies are always looking to improve NVH since a comfortable riding vehicle is a strong selling point, especially to a long-haul trucking customer. To ensure that vibration and shock are isolated from the system as much as possible, and to guarantee optimal performance, properly designed elastomeric mounts are used to create resilience between the engine and support structure. Choosing the wrong vibration isolator or vibration damper may actually make the problem worse by amplifying, which can worsen NVH, shorten the life and performance of the equipment, and result in serious malfunctions.
|Engine with Elastomeric Mounts
Elastomeric Mounts and Their Applications in Engine Isolation
Elastomeric mounts and isolation pads are ubiquitous, being used for a diverse array of applications relating to vibration and shock in industrial HVAC machinery, electronic equipment, vehicle cab mounts and engines.
These mounts are constructed of different types of thermoset and thermoplastic materials. Polymer Technologies has over 3500 elastomeric materials in its database. Each of these materials can be applied in different orientations, which means the damping and isolation they provide will also vary according to the part geometry.
The right elastomeric engine mounts will ensure that the system works more smoothly without additional noise and disturbance while the life span and performance of both the system and the mounts see marked improvements. Custom-engineered elastomeric mounts provide optimal noise and shock attenuation for specific applications and protect equipment from complex mechanical vibrations and shocks that are commonly induced by environmental conditions.
|Vibration Isolator: DuraFlex®|
These isolation mounts are successfully used on generators, radiators, pumps and motors, highway vehicles and heavy duty machinery, marine equipment, stationary and portable machinery, as well as fans and blowers. Any piece or equipment with an engine or motor is a candidate for vibration mounts. Different types of vibration isolator mounts are designed with a wide range of radial and axial loading capacities. Vibration mounts with low-profile construction are available for application where space is tight; and fail-safe designs are available for mobile applications where the motor or engine is held in place even in a catastrophic event.
Mounts are available in a variety of different design orientations catering to specific requirements and applications. Some of the ways in which they can be used as a vibration damper and isolator include:
Leveling Mounts for Machine Applications
Specifically engineered for reducing machine noise and providing adjustment and support, leveling mounts are easy to install and offer loading in the axial plane. They are typically used for machine leveling or in heavy-duty equipment.
Plateform Mounts for Transportation Equipment
Plateform style mounts are easy to install, provide uniform stress distribution, and require minimal installation space, making them compact and easy to use. They are mostly used in transportation equipment, electromechanical or electronic appliances, and office machinery.
Multi-plane Mounts for Pump and Electrical Applications
In addition to acting as a vibration isolator, multi-plane mounts can have an aluminum core and flange with rubber between them that provides uniform shock and vibration isolation in all directions. They are used in small pumps, business machines and electrical equipment.
Center-Bond Mounts for Heavy-Duty Static Load Equipment
Center-Bond mounts are typically used in heavy-duty static load equipment and machinery. They can handle high static loads. Like multi-plane mounts, they provide multidirectional engine vibration isolation. They offer loading in both axial and radial direction and have a long life since they can withstand high levels of shock and vibration.
Cylindrical Mounts for Vibration and Acoustic Isolation
Cylindrical mounts, also referred to as stud mounts, are available in a variety of sizes and shapes – as shearing or shock mounts, isolators or bumpers, electrical insulators or levelers, and as feet or snubbers. They are a cost effective solution to reduce vibration and noise.
Ring and Bushing Style Mounts for Shock & Under Hood Applications
Ring and bushing mounts, also referred to as universal mounts, are one of the most common forms of vibration mounting. Ring and bushing mounts are compact and low-profile, providing high capacity shock and vibration isolation even in severe conditions. Applications include truck, bus, marine, generators, HVAC, electronics, pumps, compressors, and blowers.
Low-Profile Mounts for Added Stability in Shock Isolation
These isolation mounts are typically composed of solvent-resistant elastomers that have the increased temperature range necessary for avionics applications. Their low-profile size enables them to be used as electronics mounts in tight places such as on aircraft.