New Magnetic Gearing Concept with Enhanced Torque


Magnetic wobbling gear

Technology abstract

An Austrian SME developed one of the world’s most effective magnetic gear boxes based on a patented, simple and unique magnetic concept with highest torque densitiy. In contrast to conventional geared drives, the force transmitting permanent magnets work contact and lubrication free. Therefore high reliability and efficiency are proven benefits of this new technology with its contactless energy transmission. The company is looking for integration projects and development partners.

Technology Description

In magnetic gears, the traditional load- and friction-bearing elements are replaced by preferably strong permanent magnets to transmit energy. There is absolutely no contact between the acting magnetic surfaces. The gearing parts are friction free and perform consistently without lubrication.
Magnetically geared drive trains
Recently, magnetic gears emerged as an alternative technology to mechanical gears and mechanical geared applications. The typical system configuration of a mechanically geared drive-train also applies to a magnetically geared system. This arrangement only replaces the mechanical gearbox with a Magnetic Wobbling Gear, requiring no changes to an existing drive train system. Magnetic gear technologies have been investigated as an alternative to both direct drive and conventional geared systems. Studies have shown that magnetically geared systems can achieve competitive power densities, paired with improved reliability and the robustness of direct drive or even pneumatic systems.
Within the very new area of magnetic gearing, the proposed Magnetic Wobbling Gearing (MWG) principle proves outstanding torque density and a very simple internal structure, so that it offers itself as one of the best choices. The MWG topology has a magnetic system torque density of up to 200 Nm/kg, depending on the unit-size.
Comparing to mechanically geared drive-trains, magnetically geared systems potentially have much higher reliability and higher efficiency, also in harsh environmental conditions.
Technical details of the proposed magnetic drive-trains with MWG:
·       Power output in the range up to kW (10 3 Watts)
·       Output Torque in the range from mNm to kNm (10-3 to 103 Newtonmeter)
·       Gearing ratio 1:10 – 1:2000 in a single gear-stage only
Apart from aerospace, the
Potential Applications of MWG are such ones, where
·       contactless and lubrication free torque conversion is of interest (highly reliable systems, vacuum and silicon wafer technique, space, cryogenic systems, food processing industries …), where
·       high efficiencies are of special interest (E-Bikes, battery driven applications, power conversion, energy harvesting, geared wind power systems, …), where
·       gearing precision is of special concern (plant- and mechanical engineering, ...).

Innovations & Advantages

·       Magnetic Gears are contact and lubrication free, so wear is dramatically reduced. On top, gears are low noise;
·       Adaptability to a wide range of torque and power (1mW to 100kW) allows application from electric actuators for mirrors in the automotive sector to wind energy converters;
·       Mechanical simplicity, robustness and reduced production costs;
·       Precision: Due to its internal working principle, MWGs deliver a completely smooth motion on input and output shaft, and thereby is superior to other magnetic gearing principles. Thus MWG deliver constant precision in both low and high load cycles. At the same time they are collision tolerant since there is no mechanical coupling between the drive train and the output shaft;
·       Elasticity: can be very desirable in a power train, for example for compliant robotic applications and safety.
·       Magnetic Wobbling Gears can be designed so as to maximise torque-output, torque density [Nm/kg], diameter or axial length with a view to reducing weight and adopting it to the space available.
·       Highly efficient: Energy conversion is practically seamless and losses via rolling friction and low magnetic hysteresis phenomena are minimal.
·       Temperature operating conditions: From cryogenic applications up to the temperature where a material's permanent magnetism changes to induced magnetism (above 300 degrees for SmCo-Magnets). The all over span exceeds 500 degrees Centigrade. 

Current and Potential Domains of Application

Automotive, e.g. electric actuators for mirrors, energy production, brushless motors, linear axle, power train, drive train, robots, lubrication-free