Magnetic bearing assembly using repulsive magnetic forces

Abstract

A magnetic bearing assembly utilizes repulsive magnetic forces between components, having magnetic sources, of the bearing at two or more gaps which are angled with respect to an axis of the inner component. Each gap provides force vectors in two directions, while allowing for relative movement of the components in a third direction. The gaps collectively provide a stable equilibrium in the first two directions, meaning that, in response to relative movement of the components in the first or second direction causing a decreased gap width, magnetic repulsive forces at the decreased gap width urge the components away from each other to return to equilibrium. The components of a radial magnetic bearing according to the invention move relative to one another rotationally, and the components of a linear magnetic bearing according to the invention move relative to one another longitudinally.

1 . A radial magnetic bearing assembly comprising: 
 a radially inner component comprising a first magnetic source having a first radially inner axially polarized end having a first polarity and a second radially inner axially polarized end having a second polarity opposite the first polarity;    a radially outer component comprising a second magnetic source having a first radially outer axially polarized end having the first polarity and a second radially outer axially polarized end having the second polarity, the first radially outer end being axially aligned with the first radially inner end and the second radially outer end being axially aligned with the second radially inner end, wherein the radially inner component and the radially outer component are disposed for relative rotation around an axis and are positioned to provide: 
 a first continuous end gap between the radially inner component and the radially outer component at the first end, wherein the first continuous gap is angled with respect to the axis and provides a first end axial force vector urging relative movement between the radially inner component and the radially outer component in a first axial direction;  
 a second continuous end gap between the radially inner component and the radially outer component at the second end, wherein the second continuous gap is angled with respect to the axis and provides a second end axial force vector urging relative movement between the radially inner component and the radially outer component in a second axial direction opposite the first axial direction,  
   wherein the magnitude of the first end axial force vector is equal to the magnitude of the second end axial force vector at equilibrium; the first continuous end gap and the second continuous end gap each provide a plurality of radial force vectors having a net magnitude of zero at equilibrium; and the bearing assembly has a radially stable and axially stable equilibrium, wherein, in response to relative movement of the radially inner component and the radially outer component causing a decrease in the gap width of at least a portion of the first continuous gap or the second continuous gap, magnetic repulsive forces at the portion of decreased gap width urge the radially inner component and the radially outer component away from each other to return to equilibrium.    
   
   
       2 . An assembly according to  claim 1 , wherein the first magnetic source comprises a permanent magnetic material and the second magnetic source comprises a permanent magnetic material.  
   
   
       3 . An assembly according to  claim 1 , wherein the first magnetic source comprises a permanent magnetic material and the second magnetic source comprises a core of highly magnetically permeable material and a coil of wire wound on the core, wherein the core is magnetized by passing a current through the coil of wire.  
   
   
       4 . An assembly according to  claim 3 , wherein the outer component is stationary and the radially inner component is a moving component.  
   
   
       5 . An assembly according to  claim 1 , wherein the angles of the first continuous gap and the second continuous gap with respect to the axis are between 30° and 60°.  
   
   
       6 . An assembly according to  claim 5 , wherein the angles of the first continuous gap and the second continuous gap with respect to the axis are about 45°.  
   
   
       7 . An assembly according to  claim 1 , wherein the radially inner component and the radially outer component comprise niodimium iron boron.  
   
   
       8 . An assembly according to  claim 1 , wherein the first continuous gap and the second continuous gap are in the shape of a truncated cone.  
   
   
       9 . An assembly according to  claim 1 , further comprising a retainer ring disposed peripherally around the radially outer component.  
   
   
       10 . An assembly according to  claim 1 , wherein the radially outer component is stationary and the radially inner component is a moving component.  
   
   
       11 . In a magnetic bearing assembly having an inner axially polarized magnetic component having an axis and at least one outer axially polarized magnetic component and using repulsive magnetic forces to control relative movement between the inner component and the at least one outer component in at most five of six degrees of freedom while permitting relative movement between the inner component and the at least one outer component in at least one degree of freedom, the improvement comprising the inner component and the at least one outer component defining at least two continuous magnetic gaps, each angled with respect to the axis and each providing force vectors in first and second directions and wherein the at least two continuous gaps collectively provide a stable equilibrium in the first and second directions, wherein, in response to relative movement of the inner component and the outer component to cause a decrease in the gap width of at least a portion of one of the gaps in the first or second direction, magnetic repulsive forces at the portion of decreased gap width urge the inner component and the outer component away from each other along the first or second direction to return to equilibrium.