Damper with electro-magnetic actuator
View Patent ↗A damper system for a vehicle is provided that includes an outer tube, a piston rod, and a piston assembly that is mounted to the piston rod and separates the outer tube into first and second working chambers. A valve assembly, mounted to the piston assembly, controls fluid flow between the first and second working chambers. A magnetic rotor is fixed to and extends annularly about the outer tube. A stator assembly is coupled to the piston rod by a spherical bearing assembly. The stator assembly includes a plurality of coils that apply an active damping force to the piston rod when energized. The coils can also generate electricity from axial movements of the piston rod relative to the outer tube. One or more glide bearings are disposed radially between the coils and the magnetic rotor in a sliding fit to stabilize the stator assembly.
1. A damper system for a vehicle, comprising:
an outer tube extending along a longitudinal axis between a closed end and a rod side end;
a piston rod extending along the longitudinal axis between a proximal end and a distal end, the piston rod extending through the rod side end in the outer tube such that the proximal end of the piston rod is disposed within the outer tube and the distal end of the piston rod is outside the outer tube;
a piston assembly slidably fitted in the outer tube for movement along the longitudinal axis;
a magnetic rotor fixed to and extending annularly about the outer tube at a location longitudinally adjacent to the rod side end of the outer tube; and
a stator assembly coupled to the piston rod adjacent to a distal end, the stator assembly including a stator carrier coupled to the piston rod, a plurality of coils that are supported on the stator carrier and extend annularly about the magnetic rotor, and at least one glide bearing that is disposed radially between the plurality of coils and the magnetic rotor, wherein the at least one glide bearing moves longitudinally with the stator assembly and is arranged in a sliding fit with the magnetic rotor.
2. The damper system of claim 1 , wherein the magnetic rotor includes an array of permanent magnets fixed to a carrier sleeve, the carrier sleeve fixed to and extending annularly about the outer tube such that the carrier sleeve is positioned radially between the array of permanent magnets and the outer tube.
3. The damper system of claim 2 , wherein the carrier sleeve is made of a ferromagnetic material and the array of permanent magnets extend annularly about the carrier sleeve in a longitudinally stacked arrangement.
4. The damper system of claim 1 , wherein the plurality of coils are longitudinally spaced by spacer blocks arranged in between the plurality of coils.
5. The damper system of claim 1 , further comprising:
at least one temperature sensor positioned in the stator assembly to monitor operating temperatures within the stator assembly.
6. The damper system of claim 1 , wherein the at least one glide bearing includes a plurality of glide bearings that are longitudinally spaced from one another by annular gaps that extend radially between the plurality of coils and the magnetic rotor.
7. The damper system of claim 1 , wherein the stator carrier includes a stator body that extends annularly about and supports the plurality of coils and a transverse portion that extends radially inwardly from the stator body to the piston rod.
8. The damper system of claim 1 , wherein the magnetic rotor includes an array of permanent magnets that have a permanent magnetic field that generates an electrical current in the plurality of coils when the piston rod moves longitudinally relative to the outer tube in an energy harvesting mode of operation for the damper system and the plurality of coils generating an electro-magnetic field in response to the application of an electrical current to the plurality of coils that interacts with the permanent magnetic field of the permanent magnets to apply a magnetic damping force to the piston rod in an active damping mode of operation of the damper system.
9. The damper system of claim 1 , wherein the plurality of coils include at least one set of three phase windings.
10. The damper system of claim 1 , wherein the stator assembly includes a wiper ring that extends annularly about and contacts the magnetic rotor in a sliding fit to prevent contaminants from entering the stator assembly.
11. The damper system of claim 1 , further comprising:
a spring seat that extends radially outwardly from the outer tube at a longitudinal position located between the closed end and the rod side end of the outer tube;
an upper strut mount coupled to the distal end of the piston rod; and
a spring extending annularly about the piston rod and stator assembly and longitudinally between the spring seat and the upper strut mount that applies a spring force to the piston rod.
12. The damper system of claim 1 , further comprising:
a position sensor arranged to measure a longitudinal position of the piston rod relative to the outer tube.
13. The damper system of claim 1 , further comprising a spherical bearing assembly coupling the stator carrier to the piston rod while permitting gimballing motion of the stator carrier relative to the piston rod, the spherical bearing assembly including:
a proximal rod nut threadably engaged with the piston rod and positioned longitudinally between a transverse portion of the stator carrier and the piston assembly;
a proximal bearing positioned longitudinally between the proximal rod nut and the transverse portion of the stator carrier, the proximal bearing including a convex bearing surface that abuts a concave surface on the transverse portion of the stator carrier;
a distal rod nut threadably engaged with the piston rod and positioned longitudinally between the transverse portion of the stator carrier and the distal end of the piston rod; and
a distal bearing positioned longitudinally between the distal rod nut and the transverse portion of the stator carrier, the distal bearing including a concave bearing surface that abuts a convex surface on the transverse portion of the stator carrier.
14. A damper system for a vehicle, comprising:
an outer tube extending along a longitudinal axis between a closed end and a rod side end;
a piston rod extending along the longitudinal axis between a proximal end and a distal end, the piston rod extending through the rod side end in the outer tube such that the proximal end of the piston rod is disposed within the outer tube and the distal end of the piston rod is outside the outer tube;
a piston assembly slidably fitted in the outer tube for movement along the longitudinal axis;
a magnetic rotor fixed to and extending annularly about the outer tube at a location longitudinally adjacent to the rod side end of the outer tube; and
a stator assembly coupled to the piston rod adjacent to a distal end, the stator assembly including a stator carrier coupled to the piston rod by a spherical bearing assembly and a plurality of coils that are supported on the stator carrier and extend annularly about the magnetic rotor.
15. The damper system of claim 14 , wherein the spherical bearing assembly includes:
a proximal rod nut threadably engaged with the piston rod and positioned longitudinally between a transverse portion of the stator carrier and the piston assembly;
a proximal bearing positioned longitudinally between the proximal rod nut and the transverse portion of the stator carrier, the proximal bearing including a convex bearing surface that abuts a concave surface on the transverse portion of the stator carrier;
a distal rod nut threadably engaged with the piston rod and positioned longitudinally between the transverse portion of the stator carrier and the distal end of the piston rod; and
a distal bearing positioned longitudinally between the distal rod nut and the transverse portion of the stator carrier, the distal bearing including a concave bearing surface that abuts a convex surface on the transverse portion of the stator carrier.
16. The damper system of claim 14 , wherein the magnetic rotor includes an array of permanent magnets that have a permanent magnetic field that generates an electrical current in the plurality of coils when the piston rod moves longitudinally relative to the outer tube in an energy harvesting mode of operation for the damper system and the plurality of coils generating an electro-magnetic field in response to the application of an electrical current to the plurality of coils that interacts with the permanent magnetic field of the permanent magnets to apply a magnetic damping force to the piston rod in an active damping mode of operation of the damper system.
17. A damper system for a vehicle, comprising:
an outer tube extending along a longitudinal axis between a closed end and a rod side end;
a piston rod extending along the longitudinal axis between a proximal end and a distal end, the piston rod extending through the rod side end in the outer tube such that the proximal end of the piston rod is disposed within the outer tube and the distal end of the piston rod is outside the outer tube;
a piston assembly slidably fitted in the outer tube for movement along the longitudinal axis;
a magnetic rotor fixed to and extending annularly about the outer tube at a location longitudinally adjacent to the rod side end of the outer tube; and
a stator assembly coupled to the piston rod adjacent to a distal end, the stator assembly including a stator carrier coupled to the piston rod and a plurality of coils that are supported on the stator carrier and extend annularly about the magnetic rotor, the stator carrier including an inside surface that faces the magnetic rotor and an outside surface opposite the inside surface,
wherein the stator assembly includes a plurality of annular slots on the inside surface of the stator carrier that house the plurality of coils.
18. The damper system of claim 17 , wherein the plurality of annular slots have a U-shaped cross-section that is open along the inside surface of the stator carrier to concentrate an electro-magnetic field generated by the plurality of coils towards the magnetic rotor.
19. The damper system of claim 18 , wherein the magnetic rotor includes an array of permanent magnets fixed to a carrier sleeve, the carrier sleeve fixed to and extending annularly about the outer tube such that the carrier sleeve is positioned radially between the array of permanent magnets and the outer tube.
20. The damper system of claim 19 , wherein the array of permanent magnets extend annularly about the carrier sleeve in a longitudinally stacked arrangement.