Electromagnetic flywheel damper and method therefor

The present disclosure relates to an electromagnetic rotary shock absorber for damping a wheel suspension component associated with a motor vehicle. The electromagnetic rotary shock absorber has a flywheel and at least one damper. The damper has a first element operably associated with the flywheel for driving the flywheel rotationally, and a second element operably associated with the wheel suspension component. The damper operates to dampen relative movement of the wheel suspension component using an inertia of the flywheel.

FIELD

The present disclosure relates to a rotary damper, and more particularly, to an electromagnetic rotary damper for a vehicular wheel suspension system.

BACKGROUND

The wheel suspension system for a vehicle may include an electromagnetic rotary damper which reduces vehicular vibrations generated at the wheel. The electromagnetic rotary damper includes an electric motor having a rotor and a stator, which are connected to a vehicle body. Such dampers are also used as an energy harvester for generating energy from the movement of the wheel suspension system. The electromagnetic rotary damper should be capable of handling low and high frequency disturbances experienced by the wheel suspension system.

SUMMARY

In one aspect the present disclosure relates to an electromagnetic rotary shock absorber for damping a wheel suspension component associated with a motor vehicle. The electromagnetic rotary shock absorber comprises a flywheel and at least one damper. The damper has a first element operably associated with the flywheel for driving the flywheel rotationally, and a second element operably associated with the wheel suspension component. The damper operates to dampen relative movement of the wheel suspension component using an inertia of the flywheel.

In another aspect the present disclosure relates to an electromagnetic rotary shock absorber for damping a wheel suspension component associated with a motor vehicle. The electromagnetic rotary shock absorber comprises a flywheel, a damper and an electronic controller. The damper is operatively disposed between the flywheel and the wheel suspension component and operates to dampen relative movement of the wheel suspension component using an inertia of the flywheel. An electronic controller is used for controlling the damper.

In still another aspect the present disclosure relates to a method for damping a wheel suspension component associated with a motor vehicle. The method comprises providing a damper in the form of an electric motor having a rotor and a stator. The method further involves operatively coupling a flywheel to the rotor to enable the flywheel to be driven rotationally by the rotor. The method also involves operatively coupling the stator to the wheel suspension component, and using a mass of the rotating flywheel to dampen movement of the wheel suspension component.

DETAILED DESCRIPTION

The present disclosure will now be described more fully with reference to the accompanying drawings. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application or uses.FIG. 1illustrates an electromagnetic rotary flywheel damper10(hereinafter “EF damper10”) for a suspension system of a vehicle. The vehicle may be any type of vehicle such as, without limitation, an automobile, van, light truck, truck or SUV.

The EF damper10includes an electric motor12, a flywheel14, first and second gearboxes16and18, and a clutch19. The gearboxes16and18may be any kind of speed multiplier (e.g., harmonic drives). The electric motor12includes a rotor20and a stator22. The stator22is connected to a suspension link24of the vehicle via the first gearbox16. The rotor20is connected to the flywheel14via the second gearbox18. The rotor20and the flywheel14are connected such that the rotor and the flywheel spin freely around one axis26independent of the vehicle body. The rotor20turns at a speed for maximum electromagnetic coupling. The flywheel14may be made of steel or any other suitable material.

A bearing20aof the rotor20is connected to, or otherwise partially supported from, a chassis28of the vehicle to carry the force of the suspension system. The clutch19may be used to couple the flywheel14to the chassis28via the second gearbox18. The gearboxes16and18are reduction gears such as planetary gears. The first gearbox16amplifies the relative movement of the suspension system to improve the resolution of the movement of the rotor20relative to the stator22.

FIG. 2Aillustrates a connection of a wheel30and the suspension link24, and where the suspension link is coupled to the stator22(shown in diagrammatic form). Movement of the wheel30is transferred to the suspension link24as an angular speed ω1.FIG. 2Bdepicts the angular speed of the suspension link24(ω1) and the nominal angular speed of the rotor20(ω2).FIG. 3illustrates a chart of various loads placed on the EF damper10plotted as current or torque vs. angular speed.

At static operation, the flywheel14is controlled to spin at a set speed by a controller of the electric motor12. The set speed of the flywheel14is seen by the stator22as a nominal angular speed ω2(i.e., the nominal angular speed of the rotor20). Motion of the suspension system is transferred to the stator22creating a relative rotation of the stator (i.e., a wheel event). More particularly, the relative movement of the suspension system is seen by the stator22as a relative variation in speed by the rotor20. Depending on a plurality of factors that include the strength of the magnetic coupling between the stator22and rotor20, the rotating speed of the flywheel14, and the impact energy of the suspension movement, the force of the relative movement is either accelerating the flywheel14or acting as a force against the rotor and/or flywheel (FIG. 3) to slightly and momentarily attenuate the angular speed of the flywheel14. This is in effect the damping force.

For a semi-active system, the EF damper10dissipates energy. For an active system, the EF damper10can create an active vertical force to the vehicle body for a certain time. As part of an active system, the EF damper10includes a clutch to vary the rotating resistance of the flywheel14. More particularly, in an active mode, a controller (or inverter)32(FIG. 1) associated with the electric motor12may regulate the speed of the flywheel14to the preselected speed. Higher forces can be generated by the electric motor12by varying the load line or resistance. Specifically, the load is varied by engaging the clutch19between the flywheel14and the chassis28of the vehicle. The controller32is controlling the torque demands of the electric motor12and speed regulation of the flywheel14. The clutch is controllable by an electrical signal either from the controller32or from a different controller.

FIG. 4illustrates the properties of the EF damper10when it is implemented as an active system. As an active system, the resistance level as seen by the rotor20, relative to the stator22, is moved (varied) by engaging the clutch19. Thus, a certain (controlled) amount of force can be created which acts on the suspension link24.

At high frequencies, the rotor20and flywheel14absorb the energy by rotating freely without being controlled by the controller32. The controller32actively controls the rotor20, and thus the angular speed of the flywheel14, at low frequency bands, which is manageable by the controller. The disturbance experienced by the EF damper10at high frequencies is absorbed by the inertia of the rotor20.

The EF damper10comprises at least one damper element for damping the relative movement of a first mass located at the wheel suspension side against the inertia of a fast spinning flywheel connected to supported from the vehicle body. The electric motor12of the EF damper10produces an electromagnetic resistance force that opposes the relative rotational movement of the flywheel. Due to the inertia of the flywheel14, harsh movements of the suspension system do not translate into high peak currents. In summary, the EF damper10of the present disclosure is a suspension rotary damper, comprising an electromagnetic motor combined with a flywheel system for harshness compliance. The EF damper10dampens the peak currents during the operation of an electromagnetic damper system by use of the flywheel.