Active vibrational damper
View Patent ↗A vibration damper and/or isolator for a rotating shaft is provided comprising a hub, an inertia element, a magneto-rheological elastic element interposed between the hub and the inertia element to non-rigidly couple the inertia element to the hub, and an electromagnet operable to produce a magnetic field across the elastic element when energized. The magneto-rheological elastic element, which may comprise a composite of magnetic-responsive particles dispersed within an elastic material, possesses a variable shear modulus that is dependent, at least in part, on the strength of a magnetic field applied to the elastic element.
1. A method of controlling vibrations in a vibrating element, the method comprising the steps of:
providing a vibrating element coupled to a rotatable shaft for rotational moment therewith;
providing a vibration damper that includes a magneto-rheological elastic element and an annular inertia element, the annular inertia element having an axially extending slot in an outer face thereof that receives at least a portion of an electromagnet, a portion of the magneto-rheological elastic element, or a portion of the vibrating element;
coupling the vibrating element to the vibration damper with the magneto-rheological elastic element between the annular inertia element and the vibrating element, wherein the frequency of the vibration damper is dependent, at least in part, on the shear modulus of the magneto-rheological elastic element;
monitoring the vibrations of the vibrating element; and
applying a magnetic field to the magneto-rheological elastic element of the damper based, at least in part, on the monitored vibrations of the vibrating element to control the shear modulus of the elastic element and therefore the frequency of the damper.
2. A method of controlling vibrations in a vibrating element as claimed in claim 1 , wherein the vibration damper further comprises a viscous damper portion containing a magneto-rheological viscous fluid, the method further comprising the step of applying a magnetic field to the magneto-rheological viscous fluid based, at least in part, on the monitored vibrations of the vibrating element.
3. A method as claimed in claim 1 , wherein applying the magnetic field includes positioning an electromagnet to produce a magnetic field across the magneto-rheological elastic element when the electromagnet is energized.
4. A method of controlling vibrations in a vibrating element as claimed in claim 1 , wherein the vibrations of the vibrating element comprise torsional vibrations.
5. A method of directly controlling the torsional vibrations of a rotating shaft, the method comprising the steps of:
providing a vibration damper comprising a magneto-rheological elastic element interposed between an annular inertia element and a hub, the annular inertia element being elastically coupled to the hub by the magneto-rheological elastic element, wherein the frequency of the vibration damper is dependent, at least in part, on the shear modulus of the elastic element;
coupling the hub of the vibration damper to a rotatable shaft for movement therewith;
monitoring the vibrations of the rotating shaft; and
applying a magnetic field to the magneto-rheological elastic element of the damper based, at least in part, on the monitored vibrations of the rotating shaft to control the shear modulus of the elastic element and therefore the frequency of the damper.
6. A method of indirectly controlling the torsional vibrations of a rotating shaft in an engine system, the method comprising the steps of:
providing a vibration damper comprising a magneto-rheological elastic element interposed between an annular inertia element and a hub, the annular inertia element being elastically coupled to the hub by the magneto-rheological elastic element, wherein the frequency of the vibration damper is dependent, at least in part, on the shear modulus of the elastic element;
coupling the hub of the vibration damper to a rotating rotatable shaft in an engine system for movement therewith;
monitoring the operating conditions of the engine system; and
applying a magnetic field to the magneto-rheological elastic element of the damper based, at least in part, on the monitored operating conditions of the engine system to control the shear modulus of the elastic element and therefore the frequency of the damper.
7. A method of isolating an associated element from the vibrations of a vibrating element, the method comprising the steps of:
providing a vibrating element coupled to a shaft for rotation therewith;
providing a vibration damper comprising a magneto-rheological elastic element, wherein the frequency of the vibration damper is dependent, at least in part, on the shear modulus of the elastic element;
providing an annular associated element capable of being concentric with the vibrating element;
interposing the vibration damper between the vibrating element and an annular associated element to couple the annular associated element to the vibrating element;
monitoring the vibrations of the associated element; and
applying a magnetic field to the magneto-rheological elastic element of the damper based, at least in part, on the monitored vibrations of the associated element to control the shear modulus of the elastic element and therefore the frequency of the damper.
8. A method of isolating an associated element from the vibrations of a vibrating element, the method comprising the steps of:
providing a vibrating element coupled to a shaft for rotation therewith;
providing a vibration damper comprising a magneto-rheological elastic element, wherein the damping value of the vibration damper is dependent, at least in part, on the damping characteristics of the elastic element;
providing an annular associated element capable of being concentric with the vibrating element;
interposing the vibration damper between a vibrating element and an annular associated element to couple the annular associated element to the vibrating element;
monitoring the vibrations of the associated element; and
applying a magnetic field to the magneto-rheological elastic element of the damper based, at least in part, on the monitored vibrations of the associated element to control the damping characteristics of the elastic element and therefore the damping value of the damper.
9. A method as claimed in claim 8 , wherein the frequency of the vibration damper is dependent, at least in part, on the shear modulus of the elastic element; and further comprising the step of applying a magnetic field to the magneto-rheological elastic element of the damper based, at least in part, on the monitored vibrations of the associated element to control the shear modulus of the elastic element and therefore the frequency of the damper.