MOTOR FOR STIRLING COOLER HAVING QUADRATURE MAGNETS
A voice-coil type cooler motor magnet assembly includes at least one radially polarized ring magnet disposed on a ferromagnetic hub. At least one quadrature magnet is disposed on the hub on each longitudinal side of the at least one ring magnet. Each quadrature magnet is polarized in a direction toward the at least one ring magnet. The hub, the at least one radially polarized ring magnet and the quadrature magnets are disposed in a ferromagnetic outer housing.
1 . A voice-coil type motor magnet assembly for a cooler, comprising:
at least one radially polarized ring magnet disposed on a ferromagnetic hub;
at least one quadrature magnet disposed on the hub on each longitudinal side of the at least one ring magnet, each quadrature magnet polarized in a direction toward the at least one ring magnet; and
wherein the hub, the at least one radially polarized ring magnet and each quadrature magnet are disposed in a ferromagnetic outer housing.
2 . The magnet assembly of claim 1 wherein each quadrature magnet is polarized at an angle with respect to the ring magnet such that a magnetic field flux density in a gap between the hub and the outer housing is maximized.
3 . The magnet assembly of claim 1 further comprising a thermal demagnetization shunt disposed between each quadrature magnet and the at least one ring magnet