The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 20, 1989
Filed:
Oct. 07, 1987
Philip A Studer, Silver Spring, MD (US);
Other;
Abstract
A brushless DC motor is disclosed wherein armature forces can be produced and controlled as both radial forces and as torque couples. A structure is described in which the normal radial destabilizing forces due to the high levels of magnetic flux linking the stator and rotor are reduced and the force gradient is moderated. This is accomplished by locating the rotor between two concentric stator coil assemblies either of which may be used for bearing or torquing to join the rotor magnets via magnetically 'soft' iron, thereby reducing the rotor mass and inertia with the consequent improvement in dynamic performance. Since the forces on the rotor are the sum of the forces produced by each individual stator coil, it is possible to combine groups of stator coils in various ways and independently control them to achieve the dual purpose. Radial position sensors and commutation sensors are included, the former to control currents in diagonally opposite pairs of stator coils in response to eccentricity as measured by the position sensors and the latter to make the resultant radial force independent of the rotor magnets angular position and polarity. The same commutation sensors also provide rotor angular information for smooth torque production in the normal manner.