Magnetic support and motor structure

Claim 2

A magnetic bearing device for supporting a rotatable member, said device comprising first and second magnetically permeable support members, at least one of said support members extending around said rotatable member, said support members being spaced apart from one another, said rotatable member having a magnetically permeable portion near each of said support members, means including a pair of coils, each extending around a separate portion of said rotatable member, for developing an axially extending magnetic flux field between each of said support members and the adjacent permeable portion of said rotatable member, sensing means connected to said coils for sensing the flux changes in said permeable portions of said rotatable member, and compensating means connected to said coils for developing in said portions magnetic flux with a direction opposite to the direction of said flux changes to support said rotatable member axially and transversely in a position adjacent but out of contact with said support structures.

Claim 3

A bearing device as in claim 1 in which said compensating means includes said coils which are connected in series, one wound in one direction around one of said portions, and the other wound in the opposite direction around the other of said portions, and positive feedback amplifier means connected to energize said coils and simultaneously develop flux in opposite directions in said permeable portions of said rotatable member.

Claim 4

A bearing device as in claim 2 in which said sensing means includes a second pair of series-connected sensing coils, each wound in an opposite direction about one of said portions, and integrating negative feedback means connected between said sensing coils and said positive feedback amplifier means.

Claim 5

A bearing device as in claim 1 in which at least one of said support members has a hole through which one end of said rotatable member extends out of said bearing device, said rotatable member having pole faces extending radially outwardly from said rotatable member internally of said bearing device adjacent said support members.

Claim 6

A structure as in claim 1 including starting means for pulling said rotatable member away from one of said support members, said starting means including swItch means actuated upon contact between said rotatable member and one of said support members, and de-activated upon elimination of such contact, said switch, when actuated, supplying electrical energy to said compensating means in a sense such as to create flux to pull said rotatable member away from the support member it is contacting.

Claim 7

A magnetic bearing structure for magnetically suspending and rotatably supporting a shaft, said structure comprising a pair of annular permanent magnets secured to said shaft, a magnetically permeable separator plate on said shaft and separating said magnets from one another, each of said magnets having a generally annularly-shaped end portion which protrudes axially from the main body of the magnet at a position spaced radially outwardly from said shaft, a housing of magnetically permeable material, said housing having two ends, each with an opening through which one end of said shaft extends, an annular protrusion at each of said openings, each of said protrusions having a portion extending axially toward and adjacent one of said magnet end portions, two drive windings and two sense windings wound around but spaced from said shaft, there being one drive winding and one sense winding on each side of said separator plate, and positive feedback amplifier means for energizing said windings so as to axially balance and maintain said shaft magnetically in a position of axial equilibrium.

Claim 8

A magnetic bearing structure for magnetically suspending and rotatably supporting a shaft, said structure comprising a pair of annular permanent magnets secured to said shaft, a magnetically permeable separator plate on said shaft and separating said magnets from one another, each of said magnets having a generally annularly-shaped end portion which protrudes axially from the main body of the magnet at a position spaced radially outwardly from said shaft, a housing of magnetically permeable material, said housing having two ends, each with an opening through which one end of said shaft extends, an annular protrusion at each of said openings, each of said protrusions having a portion extending axially toward and adjacent one of said magnet end portions, two drive windings and two sense windings wound around but spaced from said shaft, there being one drive winding and one sense winding on each side of said separator plate, and positive feedback amplifier means for energizing said windings so as to axially balance and maintain said shaft magnetically in a position of axial equilibrium.

Claim 9

Apparatus for supporting a magnetically permeable body by magnetic forces, said apparatus comprising bias means for applying to said body a magnetic bias flux forming opposite magnetic poles in said body, shunt means forming a shunt path made of magnetically permeable material and having portions adjacent each of said poles, and balancing means for sensing flux changes in said body and developing in said body balancing flux in a direction opposite to the direction of said flux changes so as to support said body magnetically in a position with gaps between said body and said portions of said shunt means, said balancing means including means for simultaneously increasing the flux across one of said gaps and decreasing the flux across the other of said gaps.

Claim 10

Apparatus for supporting a magnetically permeable body by magnetic forces, said apparatus comprising bias means for applying to said body a magnetic bias flux forming opposite magnetic poles in said body, shunt means forming a shunt path made of magnetically permeable material and having portions adjacent each of said poles, and balancing means for sensing flux changes in said body and developing in said body balancing flux in a direction opposite to the direction of said flux changes so as to support said body magnetically in a position with gaps between said body and said portions of said shunt means, said balancing means including means for simultaneously increasing the flux across one of said gaps and decreasing the flux across the other of said gaps.

Claim 11

Apparatus as in claim 7 in which said balancing means includes a pair of coils, one around one end of said body, and the other around the other end of said body, and means intermediate said coils for dividing said shunt path into two separate shunt paths.

Claim 12

An electric motor, said motor comprising, in combination, a rotatable member, magnetic bearing means for said rotatable member, said bearing means comprising a support member extending around said rotatable member, and magnetic suspension means for magnetically suspending and holding said rotatable member against axial and transverse movement relative to said support member and for holding said rotatable member out of contact with said support member, and magnetic drive means for rotating said rotatable member, said suspension means including means for developing an axial magnetic flux field between said support member and a portion of said rotatable member, means for changing the pattern of said flux field with the relative rotational positions of said rotatable member and said support member and said pattern changing means includes rotationally asymmetrical pole faces for said support member and said portion of said rotatable member.

Claim 13

An electric motor, said motor comprising, in combination, a rotatable member, magnetic bearing means for said rotatable member, said bearing means comprising a support member extending around said rotatable member, and magnetic suspension means for magnetically suspending and holding said rotatable member against axial and transverse movement relative to said support member and for holding said rotatable member out of contact with said support member, and magnetic drive means for rotating said rotatable member, said suspension means including means for developing an axial magnetic flux field between said support member and a portion of said rotatable member, means for changing the pattern of said flux field with the relative rotational positions of said rotatable member and said support member and said pattern changing means includes rotationally asymmetrical pole faces for said support member and said portion of said rotatable member.

Claim 14

A motor as in claim 9 in which said pattern changing means includes means for supplying oscillating magnetic flux to said flux field.

Claim 15

A motor as in claim 9 in which said assymmetrically-shaped pole faces are toothed.

Claim 16

A motor comprising drive means for magnetically rotating a magnetically permeable body, and magnetic apparatus for rotatably supporting said body, said apparatus comprising bias means for applying to said body a magnetic bias flux forming opposite magnetic poles in said body, shunt means forming a shunt path made of magnetically permeable material and having portions adjAcent each of said poles, balancing means for sensing flux changes in said body and developing in said body balancing flux in a direction opposite to the direction of said flux changes so as to support said body magnetically in a position with gaps between said body and portions of said shunt means and said drive means includes rotationally asymmetrical pole faces for said body and the adjacent portions of said shunt means, the asymmetry of one pole face and the opposed shunt portion being out of phase with the asymmetry of the other pole face and shunt portion.

Claim 17

A motor comprising drive means for magnetically rotating a magnetically permeable body, and magnetic apparatus for rotatably supporting said body, said apparatus comprising bias means for applying to said body a magnetic bias flux forming opposite magnetic poles in said body, shunt means forming a shunt path made of magnetically permeable material and having portions adjAcent each of said poles, balancing means for sensing flux changes in said body and developing in said body balancing flux in a direction opposite to the direction of said flux changes so as to support said body magnetically in a position with gaps between said body and portions of said shunt means and said drive means includes rotationally asymmetrical pole faces for said body and the adjacent portions of said shunt means, the asymmetry of one pole face and the opposed shunt portion being out of phase with the asymmetry of the other pole face and shunt portion.

Claim 18

A motor as in claim 12 in which said balancing means includes means for simultaneously increasing the flux across one of said gaps and decreasing the flux across the other of said gaps, and said drive means includes means for applying oscillating flux across said gaps.

Claim 19

An electrical motor comprising a stationary magnetic member, a movable magnetic member adjacent said stationary magnetic member, first flux means for creating between said movable and stationary magnetic members a magnetic flux field whose pattern changes with changes in the rotational positions of said movable and said stationary members relative to one another, second flux means for creating between said members a variable magnetic flux field to compensate for magnetic force variations between said members and maintain them adjacent but out of contact with one another and said first flux flux means includes rotationally asymmetrical pole faces between said movable and stationary members.

Claim 20

An electrical motor comprising a stationary magnetic member, a movable magnetic member adjacent said stationary magnetic member, first flux means for creating between said movable and stationary magnetic members a magnetic flux field whose pattern changes with changes in the rotational positions of said movable and said stationary members relative to one another, second flux means for creating between said members a variable magnetic flux field to compensate for magnetic force variations between said members and maintain them adjacent but out of contact with one another and said first flux flux means includes rotationally asymmetrical pole faces between said movable and stationary members.

Claim 21

A motor as in claim 14 in which said pole faces are rectangular.

Claim 22

A motor as in claim 14 in which said second flux means includes a coil around said movable member, positive feedback amplifier means for energizing said coil, and integrating negative feedback damping means for said amplifier means.