Rotary transformer

Claim 1

In a rotary transformer structure having at least one annular stator support, a rotor, at least one annular rotor support on said rotor, and a pair of annular bearings journaling said rotor in said stator support at axial spaced positions, improved transformer means including an annular excitation transformer having a first stator coil and a first rotor coil, and an annular signal transformer having a second rotor coil, a pair of annular cores each having a U-shaped cross section and being formed of a magnetically permeable material, said U-shaped cross section being defined by a bight portion and a pair of leg portions extending away from the bight portion parallel to the axis of the core, said excitation transformer being disposed in one core and the signal transformer being disposed in the other core, the improvement comprising: means for mounting said cores to at least one of said supports intermediate said spaced bearings with said bight portions in axially spaced relationship and the legs of each core extending axially away from the other core toward the bearing outboard thereof; and opposed permeable means extending toward each other radially intermediate said ends of the legs of the respective cores and defining small air gaps with said leg ends to cooperate with said U-shaped cores in substantially fully permeably enclosing the transformers and defining air gaps opening axially away from the other of said pair of cores whereby cross talk between said transformers is effectively minimized notwithstanding the disposition of the transformer inboard of said spaced bearings, each pair of associated permeable means and U-shaped core being mounted for coaxial relative rotation therebetween.