System and method for damping narrow band axial vibrations of a rotating device

• US 5,291,975 A
• Filed: 10/27/1992
• Issued: 03/08/1994
• Est. Priority Date: 10/27/1992
• Status: Expired due to Term

• Current Assignee: Perfect Galaxy International Limited
• Original Assignee: Satcon Technology Corporation
• Inventors: Hockney, Richard, Johnson, Bruce G., Eisenhaure, David, Fenn, Ralph
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US07/967,806
• Time in Patent Office: 497 Days
• Field of Search: 188/378, 188/379, 188/380, 248/550, 267/136, 367/191, 318/561
• US Class Current: 188/378
• CPC Class Codes: B63H 21/302 with active vibration damping
• CPC Class Codes: F04D 29/668 damping or preventing mechanical vibrations
• CPC Class Codes: F16C 2326/30 Ships, e.g. propelling shafts and bearings therefor in general B63H
• CPC Class Codes: F16C 39/06 using magnetic means
• CPC Class Codes: F16F 15/02 Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems F16F15/005 takes precedence ; layered products B32B; suppression of vibration in ships B63; relieving load on bearings, using magnetic means F16C39/06
• CPC Class Codes: F16F 15/10 Suppression of vibrations in rotating systems by making use of members moving with the system by balancing F16F15/22 ; yielding couplings F16D3/00 ; with flywheels acting variably or intermittently F16H ; construction providing resilience or vibration-damping for gear elements F16H55/14
• CPC Class Codes: F16F 15/18 using electric, magnetic or electromagnetic means suppression of vibrations of rotating systems by use of non-rotating magnetic or electromagnetic means F16F15/03; dynamo-electric devices H02K; control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10
• CPC Class Codes: F16F 7/1005 characterised by active control of the mass

Abstract

A system and method for damping narrow band axial vibrations of a rotating device in which a reaction mass is coupled to the rotating device and a reaction mass actuator is employed to move the reaction mass axially along the rotating device. An effect of vibrations on the rotating device is then measured, and in response the reaction mass is moved axially to damp the effect of vibrations and so the vibrations.

Claims

1. A method of damping axial vibrations of a rotating device, comprising:

coupling a reaction mass in a manner in which it has an effect on vibrations of the rotating device;

providing means for moving said reaction mass to counter vibrations from the rotating device;

measuring an effect of vibrations from the rotating device; and

moving said reaction mass in response to said measured effect to damp the effect and the vibrations.

5. The method of claim 1 in which coupling a reaction mass includes fixing the mass to the rotating device.

6. The method of claim 5 in which fixing the reaction mass includes radially constraining the reaction mass.

7. The method of claim 5 in which the reaction mass is moved axially along the rotating device.

8. The method of claim 7 in which providing means for moving said reaction mass includes mounting windings on the rotating device.

9. The method of claim 8 in which providing means for moving said reaction mass further includes coupling at least one permanent magnet to said rotating device radially spaced from said windings.

10. The method of claim 9 in which moving said reaction mass includes selectively applying current to said windings.

11. The method of claim 1 in which coupling a reaction mass includes providing a flexible coupling allowing axial mass movement and providing an axial restoring force to return the mass to its original position.

2. The method of claim I in which measuring an effect includes determining the axial acceleration of the rotating device.

3. The method of claim I in which measuring an effect includes determining the force between the rotating device and a fixed surface.

4. The method of claim I further including determining the rotational velocity of the rotating device, in which moving the reaction mass is also responsive to the determined velocity.

12. The method of claim I in which the reaction mass is coupled to a fixed member in mechanical contact with the rotating device.

13. A method of damping axial vibrations of a rotating shaft, comprising:

coupling a reaction mass to the shaft, said reaction mass including a permanent magnet and back iron constrained radially and movable axially in relation to the shaft;

coupling windings to the shaft for selectively providing a magnetic field for interacting with the field from said permanent magnet to move the reaction mass axially along the shaft;

determining the shaft rotational velocity;

measuring an effect of vibrations on the shaft; and

selectively providing current to the windings in response to the shaft rotational velocity and the measured effect to move the reaction mass to damp the effect and the vibrations.

14. A lorentz force vibration damping system for cancelling rotating shaft axial vibrations, comprising:

a reaction mass elastically coupled to the shaft;

means for measuring the shaft rotational velocity and an effect of vibrations on the shaft; and

a lorentz force reaction mass actuator, responsive to said means for measuring, for selectively moving said reaction mass axially along the shaft to suppress shaft axial vibrations.

15. The system of claim 14 in which said reaction mass is elastically coupled to the shaft with flexures that radially constrain and tend to axially restore said mass.

16. The system of claim 14 in which said reaction mass includes a permanent magnet and back iron for providing a flux path.

17. The system of claim 16 in which said reaction mass actuator includes selectively energized windings for interacting with the permanent magnetic flux to create a reaction mass axial movement force.

18. The system of claim 16 in which said reaction mass includes a plurality of circumferentially spaced permanent magnets.

19. A rotational shaft axial vibration damping system, comprising:

a reaction mass coupled to the shaft;

means for measuring an effect of shaft axial vibrations; and

means, responsive to said means for measuring, for axially moving said reaction mass to damp the measured effect and the vibrations.

20. The system of claim 19 in which said means for axially moving said reaction mass includes means for selectively applying magnetic force to said reaction mass.

21. The system of claim 20 in which said reaction mass includes a plurality of circumferentially-spaced permanent magnets and said means for selectively applying magnetic force includes selectively energizable coils for interacting with the permanent magnetic flux.