Patent portrays valve-free hydraulic drives

Chorus Motors, the Gibraltar-based company developing a novel multi-phase motor technology, has been awarded a US patent for a hydraulic drive system that eliminates the need for valves. Chorus has also been awarded another patent describing a motor that can cope with high torque overloads at low speeds while also providing sufficient voltage for high-speed operations.

The hydraulics patent (number 6,837,141) shows how an input drive system can be connected directly to an output system without valves. Chorus says the technology - called Poly-Hydro - will cut the cost, complexity and maintenance requirements of hydraulic systems, while improving their reliability and efficiency.

The technology "is still in its infancy and we`re still considering the implications and the best applications for it," says Chorus Motors` president, Isaiah Cox. "But any technology that can provide a high-performance geared system for hydraulics without the use of expensive hydraulic valves must surely have a bright future."

The new motor patent (number 6,838,791) describes an AC induction motor with variable impedance in which the windings are connected in a mesh, so that harmonic current can be supplied in a way that alters and controls the V/Hz ratios in the winding spans. This enables the motor to achieve "previously unobtainable overload capabilities".

• Boeing Phantom Works, the aerospace giant`s advanced r&d operation, has commissioned Chorus Motors to design and build an electric drive system for aircraft that would propel them on the ground without needing their jet engines or tow tugs. The system would give pilots complete control of an aircraft`s ground movements, as well as boosting fuel efficiency and allowing faster flight turnarounds.