Air gap magnetic coupling with counterbalanced force

Patent metadata

Field	Value
Publication number	US-12015320-B2
Application number	US-202016869459-A
Country	US
Kind code	B2
Filing date	May 7, 2020
Priority date	May 7, 2020
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A magnetic coupling assembly includes a first balancing magnet positioned and surrounding drive magnets and, across a gap, a second balancing magnet and surrounding driven magnets. The drive magnets when rotated drive the driven magnets to rotate. The balancing magnets generate a repulsive force, which counterbalances an attractive force generated by the drive magnets and driven magnets. The assembly may be utilized in a pump for contactless coupling of a motor shaft to a pump shaft. The driven side of the assembly may be hermetically sealed, such as with a liquid crystal polymer boundary interposed in the gap.

First claim

What is claimed is:

1. A pump assembly, comprising:
a drive shaft rotatable on a drive axis;
a driven shaft rotatable on the drive axis;
a magnetic coupling assembly comprising:
a drive magnet assembly coupled to the drive shaft, the drive magnet assembly comprising a first balancing magnet positioned on the drive axis, and a drive magnet coaxially positioned with the first balancing magnet;
a driven magnet assembly coupled to the driven shaft, the driven magnet assembly comprising a second balancing magnet positioned on the drive axis, and a driven magnet coaxially positioned with the second balancing magnet, wherein:
the drive magnet assembly is spaced from the driven magnet assembly by an axial gap, with the first balancing magnet facing the second balancing magnet across the axial gap, and the drive magnet facing the driven magnet across the axial gap;
the drive magnet and the driven magnet are configured to drive rotation of the driven magnet in response to rotation of the drive magnet, and to generate an axial attractive force between the drive magnet and the driven magnet; and
the first balancing magnet and the second balancing magnet are configured to generate an axial repulsive force between the first balancing magnet and the second balancing magnet that counterbalances the axial attractive force;

a pump head comprising a fluid inlet, a fluid outlet, and a pumping stage, the pumping stage comprising a pump rotor communicating with the driven shaft,
wherein rotation of the drive shaft drives rotation of the pump rotor via the magnetic coupling assembly, and the pumping stage is configured to pump fluid from the fluid inlet to the fluid outlet in response to the rotation of the pump rotor;

a structural boundary disposed in the axial gap between the drive magnet assembly and the driven magnet assembly, wherein the structural boundary is composed of an electrically insulating material that is effective to prevent or minimize permeation of gases through the structural boundary including the fluid pumped by the pumping stage; and
a casing enclosing the driven magnet assembly, wherein the casing comprises the structural boundary and is attached to or integrated with the pump head, and the casing at least partially defines a hermetic barrier configured to fluidly isolate the driven magnet assembly and at least part of the pump head from an ambient outside the casing.

2. The pump assembly of claim 1 , wherein the electrically insulating material is a liquid crystal polymer.

3. The pump assembly of claim 1 , wherein the first balancing magnet comprises a first inside face and has a first polarity at the first inside face, the second balancing magnet comprises a second inside face facing the first inside face across the axial gap and has a second polarity at the second inside face, and the first polarity and the second polarity are the same.

4. The pump assembly of claim 1 , wherein the drive magnet and the driven magnet comprise one of the following configurations:
the drive magnet comprises a plurality of drive magnets circumferentially spaced from each other about the drive axis and surrounding the first balancing magnet, and the driven magnet comprises a plurality of driven magnets circumferentially spaced from each other about the drive axis and surrounding the second balancing magnet;
the drive magnet comprises a plurality of drive magnets circumferentially arranged with alternating polarities about the drive axis, and the driven magnet comprises a plurality of driven magnets circumferentially arranged with alternating polarities about the drive axis;
the drive magnet comprises an annular structure magnetized with a plurality of dipoles circumferentially arranged with alternating polarities about the drive axis, and the driven magnet comprises an annular structure magnetized with a plurality of dipoles circumferentially arranged with alternating polarities about the drive axis;
the drive magnet is configured as a Halbach array, and the driven magnet is configured as a Halbach array.

5. The pump assembly of claim 1 , wherein the pump rotor comprises one of: a rotary vane component; a crank; a cam; a gear; a screw; a Roots rotor; a claw.

6. The pump assembly of claim 1 , wherein:
the pump rotor comprises an orbiting scroll blade;
the pumping stage further comprises a stationary scroll blade nested with the orbiting scroll blade; and
the orbiting scroll blade is configured to move in an orbiting manner relative to the stationary scroll blade in response to rotation of the driven shaft, to create at least one moving pocket between the orbiting scroll blade and the stationary scroll blade effective to pump fluid.

7. The pump assembly of claim 6 , wherein the pumping stage further comprises a crank positioned in eccentric relation to the driven shaft and configured to move in an orbiting manner in response to rotation of the driven shaft, and the orbiting scroll blade is coupled to the crank.

8. A method for operating the pump assembly of claim 1 , the method comprising:
rotating the drive magnet assembly about the drive axis to drive rotation of the driven magnet assembly about the drive axis via the magnetic coupling; and
counterbalancing the axial attractive force by generating an axial repulsive force between first balancing magnet and the second balancing magnet.

9. The method of claim 8 , wherein the drive magnet assembly and the driven magnet assembly comprise one of the following configurations:
the drive magnet assembly comprises a plurality of drive magnets circumferentially spaced from each other about the drive axis, and the driven magnet assembly comprises a plurality of driven magnets circumferentially spaced from each other about the drive axis and facing the plurality of drive magnets across the axial gap;
the drive magnet assembly comprises a plurality of drive magnets circumferentially arranged with alternating polarities about the drive axis, and the driven magnet assembly comprises a plurality of driven magnets circumferentially arranged with alternating polarities about the drive axis;
the drive magnet assembly comprises an annular drive magnet magnetized with a plurality of dipoles circumferentially arranged with alternating polarities about the drive axis, and the driven magnet assembly comprises an annular driven magnet magnetized with a plurality of dipoles circumferentially arranged with alternating polarities about the drive axis;
the drive magnet assembly comprises a drive magnet configured as a Halbach array, and the driven magnet assembly comprises a driven magnet configured as a Halbach array.

Assignees

• Agilent Technologies Inc

Inventors

• Forni Ronald J

Classifications

• H02K7/10

  Structural association with clutches, brakes, gears, pulleys or mechanical starters · CPC title

• F04C18/0215

  where only one member is moving · CPC title

• H02K49/104

  Magnetic couplings consisting of only two coaxial rotary elements, i.e. the driving element and the driven element · CPC title

• F05C2225/00

  Synthetic polymers, e.g. plastics; Rubber · CPC title

• F04C27/005

  Axial sealings for working fluid · CPC title