초록 ▼

A power sensor for providing an output signal indicative of the power transmitted by a rotating torqued member comprises a magnetoelastically active element for producing a magnetic field varying with the applied torque and a field modulating means for modulating the magnetic field in a periodic man

A power sensor for providing an output signal indicative of the power transmitted by a rotating torqued member comprises a magnetoelastically active element for producing a magnetic field varying with the applied torque and a field modulating means for modulating the magnetic field in a periodic manner which is indicative of the speed of member rotation. A magnetic field vector sensor in the form of a coil senses the amplitude of the time rate of change of the modulated field for providing an output signal which is linearly indicative of the power transmitted by the rotating member. The field modulating means preferably comprises at least one ring having some uniformly spaced salient feature, such as gear-like teeth, around the periphery thereof. In one embodiment, the magnetoelastically active element comprises a ring of material endowed with an effective uniaxial magnetic anisotropy such that the circumferential direction is the easy axis, and magnetically polarized in a substantially circumferential direction. The ring is attached to the torqued member, such as a rotating shaft, so that application of a torque to the shaft is transmitted to the ring. In another embodiment, the magnetoelastically active portion includes two or more axially distinct, magnetically contiguous, oppositely polarized circumferential regions.

대표청구항 ▼

A method of sensing the power transmitted by a rotating torqued member extending in an axial direction, comprising the steps of: (a) providing a magnetoelastically active ferromagnetic magnetostrictive element endowed with an effective uniaxial magnetic anisotropy having the circumferential directio

A method of sensing the power transmitted by a rotating torqued member extending in an axial direction, comprising the steps of: (a) providing a magnetoelastically active ferromagnetic magnetostrictive element endowed with an effective uniaxial magnetic anisotropy having the circumferential direction as the easy axis and which is magnetically polarized in a circumferential direction, said element being directly or indirectly attached to or forming part of the surface of said torqued member such that torque applied to the member is proportionally transmitted to said element; (b) producing a magnetic field as a consequence of the application of torque to said member; (c) modulating the torque-created magnetic field in a periodic manner, the period being indicative of the speed of member rotation; and (d) sensing, at a position proximate to said magnetoelastically active element, the amplitude of the time rate of change of said modulated magnetic field as an indication of the power transmitted by said member.