Magnetic assembly and vacuum pump

Abstract

Magnetic assembly 50 for a rotor 26 such as a molecular drag vacuum pump, comprising a first rotated magnet 54 connected to the rotor and, a static damper element 60 arranged axially next to the first

Claims

1. Magnetic assembly for a rotor preferably of a molecular drag vacuum pump, comprisinga first rotated magnet to be connected to the rotor and rotated together with the rotor,a static damper element arranged axially next to the first rotated magnet, acting as a damper magnet to induce eddy currents into the static damper element,a rotated yoke extending radially and arranged axially next to the same first rotated magnet,a static coil configured to generate a magnetic field, anda static yoke connected to the static coil and arranged directly next to the rotated yoke to induce an axial magnetic force into the rotated yoke such that the first rotated magnet at the same time acts as a bias magnet2, Magnetic assembly according to claim 1, wherein the static yoke surrounds the static coil and comprises a gap, wherein the rotated yoke extends into the gap.

3. Magnetic assembly according to claim 1 or 2, wherein the rotated yoke and / or the static yoke are made from a magnetic material.

4. Magnetic assembly according to any of claims 1 to 3, wherein the static damper element is made of a conductive material.

5. Magnetic assembly according to any of claims 1 to 4, wherein the first rotated magnet comprises a first axial end and an opposite second axial end, wherein the static damper element is arranged directly axially next to the first axial end and the rotated yoke is connected to the second axial end.

6. Magnetic assembly according to any of claims 1 to 5, comprising a second rotated magnet.

7. Magnetic assembly according to claim 6, wherein the second rotated magnet is arranged axially next to the first rotated magnet in a distance to create a gap in-between, wherein preferably the static damper element extends into the gap between the first rotated magnet and the second rotated magnet.

8. Magnetic assembly according to any of claims 1 to 7, wherein the damper element is L-shaped or T-shaped comprising an axial part extending in an axial direction, wherein the axial part is radially next to the first rotated magnet and / or the second rotated magnet, and a radial part extending in a radial direction, wherein the radial part is arranged axially next to the first rotated magnet and / or the second rotated magnet.

9. Vacuum pump, in particular a molecular drag pump, comprising a rotor assembly rotatably supported by one or more radial bearings and comprising a magnetic assembly according to any of claims 1 to 8 for axial support and damping,10. Method for assembly of a vacuum pump comprising the steps of:Providing a housing element;Providing a rotor and inserting the rotor at least partiaHy into the housing element;Mounting subsequently a first rotated magnet onto the rotor, a static damper eiement to the housing eiement, a rotated yoke to the rotor, a static yoke to the housing and a static coil to the housing to create a magnetic assembly according to any of claims 1 to 9.

11. Method according to claim 10, wherein a first part of the static yoke, the rotated yoke, the first rotated magnet, the damper element and a second rotated magnet are assembled in this order.

12. Method according to claim 10, wherein a first part of the static yoke, the first rotated magnet, the damper element, a second rotated magnet and the rotated yoke are assembled in this order.

13. Method according to claim 10, wherein a first part of the static yoke, the damper element, the first rotated magnet and the rotated yoke are as-sembled in this order.

14. Method according to claim 10, wherein a first part of the static yoke, the rotated yoke, the first rotated magnet and the damper element are assembled in this order.19

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