Stainless steel gears feature in latest Airbus

Edited by the Engineeringtalk editorial team Sep 30, 2005

The latest Harmonic Drive technology is being used in a specially designed trolley lift system, now being fitted to the latest Airbus A340-600, the world's longest passenger aircraft.

The latest Harmonic Drive technology is being used in a specially designed trolley lift system, now being fitted to the latest Airbus A340-600, the world's longest passenger aircraft.

The Harmonic Drive units are mounted outside the passenger cabin and are used to elevate and lower each lift, providing an extremely precise and controllable drive in conditions where operating temperatures and pressures can be extremely low.

The Airbus A340-600 is used by air lines around the world for long distance flights and has impressive dimensions of 75.30 metres long by 5.64 metres wide, and a height of 17.3 metres with a wing span of 63.64 metres.

The aircraft is capable of holding up to 345 passengers, plus 17 crew members and over 40 tonnes of cargo.

Ensuring the comfort of the passengers during long haul flights is crucial, and the flight attendants play a vital role, using specially designed lifts to move serving trolleys up from a storage area located beneath the passenger deck.

These specially designed lifts were designed and developed by Extel Systems Wedel (ESW) in conjunction with Airbus Germany.

ESW is a leading supplier of innovative solutions for the civil and defence industry, with particular emphasis on the field of vehicle and aircraft equipment, drive and stabilisation technology, power management and service.

Developing a lift system onboard an aircraft is extremely challenging, as it is unlike conventional passenger or freight lifts.

For example, the specially designed trolley system had to be of the lowest possible weight, with a small footprint, while generating only minimal operating noise, yet be extremely stabile and sufficiently powerful to lift trolleys full of food and drinks, up to 240kg in weight.

Each aircraft has a double lift arrangement and can be operated independently.

The trolleys are moved vertically by toothed belts, which are driven via pulley mechanisms mounted at the low deck level.

The lifts are fully encased and can be operated from above as well as below, and can only move when the door for loading and unloading is closed and sealed.

The precision drive capability for the trolley lift is provided by Harmonic Drive HFUC-40 gears.

These gears are constructed from all stainless steel parts, offer low noise levels, weigh only 1.7kg and are extremely compact, with each component set measuring just 135 x 53mm in size.

In addition, they are capable of withstanding a wide range of operating temperatures and pressures, with the all stainless steel construction eliminating the risk of differential expansion or contraction, which is often found in competing products manufactured from dissimilar materials.

This construction also ensures that the drives have a minimum operating life of 20 years with only minimal maintenance requirements.

The successful installation and operation of the Harmonic Drive component sets in the trolley lift system onboard the A340 has also led to the same products now being specified on the new Airbus A380.