Contact free magnetic bearing

Claim 2

A contact-free magnetic bearing assembly having a member supported magnetically for movement relative to a support structure, spaced magnetic poles positioned facing one another and also having opposite polarities of those poles which face one another, said poles forming a continuous magnetic circuit having a magnetic path between said poles, a magnetic member between said poles through which said magnetic path passes to support said magnetic member for movement in said path and relative to said poles, the opposite magnetic poles producing a stray range bordering said path adjacent said movable member and adjacent the gaps between the movable member and the opposite magnetic poles, electromagnetic means adjacent said path in said stray range bordering said gaps forming a magnetic field parallel to said magnetic path to produce opposed magnetic forces acting on said magnetic member adjacent the opposite poles to oppose movement of said member out of said path, and sensing means detecting changes in position of said magnetic member relative to said poles and altering the current flow through said electromagnetic means to oppose movement of said magnetic member out of said path between said poles.

Claim 3

A contact-free magnetic bearing according to claim 1 in which said electromagnetic means comprises a coil means adjacent and in surrounding relation to each said gap in a plane perpendicular to direction of the magnetic field extending between said poles.

Claim 4

A contact-free magnetic bearing according to claim 1 which includes sensing means sensitive to variations in the relative positions of said members from an equilibrium position for energizing said electromagnetic control means to develop influences in said gaps tending to restore said equilibrium position.

Claim 5

A contact-free magnetic bearing according to claim 1 in which said poles include at least pole pieces at the ends of said poles nearest one another which are formed of a high coercive material with low magnetic conductivity.

Claim 6

A contact-free magnetic bearing according to claim 1 in which said electromagnetic means comprises a pair of coils on respectively opposite sides of said magnetic path, each having a side adjacent each air gap, the currents in said coils flowing in respectively opposite directions when the coils are energized.

Claim 7

A contact-free magnetic bearing according to claim 1 in which said support structure includes a rail extending perpendicular to the axis of said magnetic field, said magnetic member being movable in a direction parallel to the rail.

Claim 8

The combination according to claim 1, characterized in that the poles are made of a highly coercive material having low magnetic conductivity.

Claim 9

The combination according to claim 1, characterized in that the control current flowing in the electromagnetic means is regulated by the output signal from a phase-bridge discriminator containing the control-current guides as components.

Claim 10

The combination according to claim 1 characterized in that at least one of the parts of the electromagnetic means in the stray range of the one air gap is connected, in an electrically conducting manner, with at least one part of the control means in the stray range of the other air gap.

Claim 11

The combination according to claim 1, characterized in that a part of the electromagnetic means of the one gap is joined to a part of the electromagnetic means of the other gap to make a closed annular conductor circuit.

Claim 12

The combination according to claim 1, characterized in that the magnetizable part of the magnetic member is in the form of a rail running at right angles to the magnetic flux, within the gap between the poles, the poles being secured to an object moving along the said rail without coming into contact therewith.

Claim 13

A contact-free magnetic bearing assembly having a member supported magnetically for rotary movement about its axis relative to a support structure, comprising: opposite magnetic poles on said support structure forming a continuous magnetic path, a rotary magnetic member between said opposite poles in said magnetic path with its axis of rotation parallel to said path, so that the said magnetic member is supported out of contact between said opposite poles with gaps between said poles and magnetic member, said opposite magnetic poles forming a stray range bordering said magnetic path opposite each of said gaps, electromagnetic means adjacent each of said gaps having a control current therein to form a magnetic field adjacent said gap parallel to said magnetic path, the magnetic fields adjacent said two gaps being in opposite directions along an axial line, and each magnetic field adjacent a gap being in opposite, axial directions on opposite sides of said rotary members to oppose movement of said member out of said path, and sensing means detecting changes in position of said magnetic member relative to said poles and altering the control current flow through said electromagnetic means to oppose movement of said magnetic member out of said path between said poles.

Claim 14

A contact-free magnetic bearing assembly having a member supported magnetically for rotary movement about its axis relative to a support structure, comprising: opposite magnetic poles on said support structure forming a continuous magnetic path, a rotary magnetic member between said opposite poles in said magnetic path with its axis of rotation parallel to said path, so that the said magnetic member is supported out of contact between said opposite poles with gaps between said poles and magnetic member, said opposite magnetic poles forming a stray range bordering said magnetic path opposite each of said gaps, electromagnetic means adjacent each of said gaps having a control current therein to form a magnetic field adjacent said gap parallel to said magnetic path, the magnetic fields adjacent said two gaps being in opposite directions along an axial line, and each magnetic field adjacent a gap being in opposite, axial directions on opposite sides of said rotary members to oppose movement of said member out of said path, and sensing means detecting changes in position of said magnetic member relative to said poles and altering the control current flow through said electromagnetic means to oppose movement of said magnetic member out of said path between said poles.

Claim 15

A magnetic bearing assembly as claimed in claim 12, said opposite magnetic poles being permanent magnetic members producing a constant magnetic path in a magnetic circuit, and said electromagnetic means being constituted by an electromagnetic coil bordering each gap and coaxial with the axis of said rotary member to form a magnetic field about said coil and coaxial with said rotary member, the control currents in said electromagnetic means being approximately zero in condition of equilibrium of said rotary member in said magnetic path.

Claim 16

A contact-free magnetic bearing according to claim 10 in which said members are rotationally symmetric about the axis of said magnetic field.

Claim 17

A contact-free magnetic bearing according to claim 12 in which said poles are in the form of coaxial tubular elements having one and the same diameter at the ends nearest one another.

Claim 18

A contact-free magnetic bearing according to claim 12 in which said support structure includes a portion on the axis of said magnetic field forming a flux return path between said poles.

Claim 19

A contact-free magnetic bearing according to claim 12 in which said support structure includes a portion on the axis of said magnetic path smaller in diameter than said poles and connected thereto and forming a flux return path between said poles.

Claim 20

A contact-free magnetic bearing according to claim 12 in which said electromagnetic means are adapted for connection in a bridge circuit which, in turn, controls the supply of energizing current to said coils.

Claim 21

The combination according to claim 12, characterized in that the magnetizable part of the rotary member and the poles are made rotationally symmetrical in relation to the direction of the magnetic path.

Claim 22

The combination according to claim 12, characterized in that the magnetizable part of the body, and the poles, are made of coaxially arranged pieces of tube having the same diameter at the gap.

Claim 23

The combination according to claim 12, characterized in that a flux conductor, running along the axis of rotation of the magnetic member and the poles, is provided for the return of the magnetic flux.

Claim 24

A contact-free magnetic bearing assembly, comprising: an annular rotor mounted by the bearing for rotation about a vertically extending central axis, and an assembly for mounting the rotor, the assembly comprising: a central vertically extending flux conductor of ferro magnetic material aligned with the central axis and having ends which extend beyond the ends of the rotor; pole pieces secured to opposite ends of the flux conductor; an annular permanent magnet secured to said pole pieces on each end of said flux conductor, the permanent magnets having poles oriented in the same direction wherein the permanent magnets cooperate with the flux conductor and its ends to form a closed magnetic circuit, the permanent magnets being spaced apart to define a space which is slightly wider than the length of the annular rotor wherein gaps occur between the ends of the rotor and each magnet while the rotor is suspended in the mounting assembly by the magnetic circuit, whereby the magnetic field extends across the gaps and strays laterally of the gaps; coils positioned adjacent to each gap within the range of the stray magnetic fields occurring laterally of the gaps, said coils forming electromagnetic means upon passing a control current therethrough to form opposed magnetic fields adjacent to the gaps parallel to the magnetic paths across the gaps, whereby the magnetic fields oppose axial movement of the rotor out of the path and out of equilibrium, said coils sensing changes of the position of the rotor relative to the poles whereby said sensed changes alter the control current flow through said coils to oppose movement of said rotor out of equilibrium between the poles.

Claim 25

A contact-free magnetic bearing assembly, comprising: an annular rotor mounted by the bearing for rotation about a vertically extending central axis, and an assembly for mounting the rotor, the assembly comprising: a central vertically extending flux conductor of ferro magnetic material aligned with the central axis and having ends which extend beyond the ends of the rotor; pole pieces secured to opposite ends of the flux conductor; an annular permanent magnet secured to said pole pieces on each end of said flux conductor, the permanent magnets having poles oriented in the same direction wherein the permanent magnets cooperate with the flux conductor and its ends to form a closed magnetic circuit, the permanent magnets being spaced apart to define a space which is slightly wider than the length of the annular rotor wherein gaps occur between the ends of the rotor and each magnet while the rotor is suspended in the mounting assembly by the magnetic circuit, whereby the magnetic field extends across the gaps and strays laterally of the gaps; coils positioned adjacent to each gap within the range of the stray magnetic fields occurring laterally of the gaps, said coils forming electromagnetic means upon passing a control current therethrough to form opposed magnetic fields adjacent to the gaps parallel to the magnetic paths across the gaps, whereby the magnetic fields oppose axial movement of the rotor out of the path and out of equilibrium, said coils sensing changes of the position of the rotor relative to the poles whereby said sensed changes alter the control current flow through said coils to oppose movement of said rotor out of equilibrium between the poles.

Claim 26

The contact-free magnetic bearing of claim 22, wherein each permanent magnet is an assembly including an annular permanent magnet member and a pole piece disposed between the permanent magnet member and gap, and wherein the pole pieces have a surface juxtaposed with the gap having a width which is substantially equal to the thickness of the rotor wall.

Claim 27

The contact-free magnetic bearing of claim 22 wherein the width of the permanent magnet is substantially equal to the thickness of the rotor wall.