ELECTROMAGNETIC SUSPENSION AND POSITIONING DEVICE WITH INHERENT DYNAMICAL STABILITY IN THREE DIMENSIONS

• US 3,572,854 A
• Filed: 01/05/1968
• Issued: 03/30/1971
• Est. Priority Date: 01/05/1968
• Status: Expired due to Term

• Current Assignee: Gordon T. Danby
• Original Assignee: Gordon T. Danby
• Inventors: Danby, Gordon T.
• Application Number:
  US04/696,069
• Time in Patent Office: 1,180 Days
• US Class Current: 310/90.5
• CPC Class Codes: F16C 32/0408 Passive magnetic bearings
• CPC Class Codes: F16C 32/044 Active magnetic bearings
• CPC Class Codes: H01F 7/206 Electromagnets for lifting, handling or transporting of magnetic pieces or material electromagnets for guidance of vehicles, workpieces B65G21/2009; for magnetic suspension or levitation H02N15/00

Abstract

Machine bearings and positioning devices are disclosed which utilize electromagnetic induction between a quadrupole component of magnetic field and a pair of orthogonally arranged closed inductor loops. A quadrupole magnet (a magnet which generates a quadrupole component of magnetic field) is rigidly mounted either upon the movable (or rotor) member or upon the stator member of the device. The closed loops are rigidly mounted upon the other member. The quadrupole magnet is composed of permanent magnets or of ferroelectromagnets, or is an air-cored electromagnet structure. Either or both the magnet and the closed loops can be superconductors. Axial stability is provided either by locating the closed loops partially within and partially without the quadrupole component of magnetic field or by utilizing auxiliary electromagnetic thrust sensitive devices at one or both ends of the shaft of the device.

Claims

1. An electromagnetic positioning and stabilizing system, comprising, in combination, first and second members, said first member comprising two closed inductive loops having a common central axis and inclined to each other at a material angle, means integral with said second member for generating a multipole component of magnetic field, said second member at least partially surrounding said first member and said first member being located at least partially within the magnetic field of said second member, said first and second members cooperating to provide forces for determining the relative position of said members in radial directions with respect to said common axis, and means to cause electromagnetic interaction between said first and second members to generate the required positioning and stabilizing forces therebetween.

2. Apparatus in accordance with claim 1, in which the said inductive loops are substantially at right angles with each other.

3. Apparatus in accordance with claim 1, together with axial positioning and stabilizing means to position and stabilize the relative position of said first and second members along the direction parallel to said common central axis.

4. Apparatus in accordance with claim 1, together with programming means for controlling the magnetic strength of individual poles of said multipole component of magnetic field, thereby to vary the relative position of said first and second members as a desired function of time.

5. Apparatus in accordance with claim 4, together with means for continuously sensing the relative position of said first and second members, and feedback means for detecting deviation of said relative position from a predetermined program of relative position as a function of time.

6. Apparatus in accordance with claim 3, in which said axial positioning and stabilizing means comprises means energized by electromagnetic interaction between a portion of said first member and the magnetic field of said second member to provide a restoring force along said common axis.

7. Apparatus in accordance with claim 3, in which said axial positioning and stabilizing means comprises an additional inductive loop rigidly attached to said first member, in electromagnetic interaction relationship to the magnetic field of said second member.

8. Apparatus in accordance with claim 3, in which said axial positioning and stabilizing means comprises a dipole magnet rigidly attached to said second member, together with aN inductive loop rigidly attached to said first member and noncentrally located within the magnetic field of said dipole magnet.

9. Apparatus in accordance with claim 3, together with means to produce a dipole magnetic field asymmetrically located with respect to said first member.

10. Apparatus in accordance with claim 1, in which the said common central axis is substantially vertical, and in which there is an additional element comprising means employing an electromagnetic restoring force to support the weight of said second member and attachments thereof and for positioning and stabilizing said second member in the vertical direction.

11. Apparatus in accordance with claim 1, together with a third member substantially like said first member and mounted upon a common central axis with said first member, a fourth member substantially like said second member, located within the magnetic field of said third member and cooperating therewith to provide forces for determining the relative position of said third and fourth members, together with means to provide axial positioning and stabilizing of said second and fourth members as a unit with respect to said common axis.

12. Apparatus in accordance with claim 1, in which at least one of said first and second members comprises superconducting means.

13. Apparatus in accordance with claim 1, comprising means integral with said second member for generating a quadrupole component of magnetic field.

14. Apparatus in accordance with claim 1, comprising a rotor and a stator wherein said rotor is attached to only one of said first and second members and said stator is attached to the other of said members, whereby said rotor is electromagnetically suspended and the axis of rotation of said rotor is radially stabilized with respect to the central axis of said stator.

15. Apparatus in accordance with claim 1, comprising means integral with said second member for generating a six-pole magnetic field and in which said first member comprises a pair of quadrupole loops at substantially 45* with respect to each other.

16. Apparatus in accordance with claim 1, in which said first member includes two resistive damping, auxiliary loops connected in series opposition to each other, said loops being positioned in portions of said magnetic field of opposite polarity whereby substantially no net current flows in said damping auxiliary loops when said first member is in an equilibrium position but whereby when said first member is disturbed from its equilibrium position a net current flows through said last-mentioned loops to provide a restoring force thereon.