No Friction, Linear-Rotary Converter

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This device attacks the age old problem of friction, while expanding the range of motion, raising efficiency, and offering virtually unlimited life. It is the first spiral magnetic bearing; making a non-contacting screw thread. A few parts have the functionality of a multi-stage gear train. The size and parts reduction lowers the cost while improving performance and controllability.

Gear reducers, especially long-life reversible types, are found in all types of machinery and automobiles, from window actuators to power steering and automation. Dozens of high precision reliable devices are used as mirror segment actuators in the Webb telescope being built for NASA and non-contacting devices are ideal for 'cleanroom' facilities making semiconductors or pharmaceuticals. How this rotary to linear device works is readily seen by a screw and nut: in this case, oppositely magnitized so that flux flows between the inner and outer element. A control wire is wound in the threads of the screw. Control current causes its flux to circulate through the adjacent tooth, deflecting the permanent magnet flux to either side, generating differential forces to keep the tooth centered and out of contact with oppositely polarized teeth.

Ordinary manufacturing easily produces the steel parts. The production costs of the sensors and control electronics has been dropping sharply with their size and volume.


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  • Name:
    Philip Studer
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    hand calulations
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    need for higher efficiency, reliability
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