IMPROVEMENT OF NOISE LEVELS IN THE YACHTING INDUSTRY
In most modern propulsion installations, engine vibrations are well isolated from the ship ’s foundation by means of excellent resilient engine mounts. However, engine vibrations are also transmitted over the coupling to the gearbox. Semi-elastic gearbox mounts used nowadays have a relative high stiffness compared to other mounts used on machinery, due to the torque transmitting function. As a result, low-frequency engine vibrations are poorly isolated and transferred to the ship’s foundation. The newly developed Torque Compensation System provides a mounting option with only a fraction of the stiffness compared to conventional gearbox mounts. Soft gearbox mounts in combination with light weight high torque gearboxes would normally result in unacceptable torque displacements. However with the TCS compensating for torque displacements, softer gearbox mounts become an option.
The mount consists of two conical rubber spring elements supporting the gearbox weight and two
air springs that can produce a counterforce to compensate for torque displacements. The rubber
conical elements are height adjustable for alignment purposes. Internal adjustable displacement
limiters prevent excessive displacements of the gearbox under all conditions, therefore there is
no need for external limiters. The TCS control unit constantly compares the measured gearbox
position with the gearbox neutral position and ( i f necessary ) adjusts the air spring pressures to
maintain the gearbox position.