Back to results
US 5,465,627 AGranted
Circularly magnetized non-contact torque sensor and method for measuring torque using same
AssigneeMagnetoelastic Devices, Inc.
InventorIvan J. Garshelis
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeMagnetoelastic Devices, Inc.
InventorIvan J. Garshelis
Estimating the term…
A torque sensor comprises a magnetoelastically active element, and a magnetic sensor, such as a Hall effect sensor, responsive to the field of the magnetoelastically active portion. In the preferred embodiment, the magnetoelastically active portion 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. The torque on the ring reorients the circumferential magnetic orientation of the ring, producing a helical magnetic orientation having both circumferential and axial components. A magnetic field vector sensor is mounted on a flux collector in a fixed position relative to the ring and oriented so that it responds only to axial magnetic field components of the ring. The output of the sensor is thus proportional to the change in orientation of the magnetization resulting from torque applied to the shaft and transmitted to the ring.
A transducing ring for attachment directly or indirectly to a member to which a torque is applied about an axis extending axially thereof such that torque applied to said member is proportionally transmitted to said ring, said ring comprising a ferromagnetic, magnetostrictive, magnetoelastically active element which is endowed with an effective uniaxial magnetic anisotropy having the circumferential direction as the easy axis and is magnetically polarized in a circumferential direction, said element having, when no torque is applied to said member, a circumferential magnetic orientation having only a circumferential component and, when a torque is applied to said member, a helical magnetic orientation having both circumferential and axial components, said ring producing a magnetic field varying with the torque applied to said member.
A transducer attached directly or indirectly to or forming a part of a member to which a torque is applied about an axis extending axially thereof such that torque applied to said member is proportionally transmitted to said transducer, said transducer comprising a ferromagnetic magnetostrictive magnetoelastically active element which is endowed with an effective uniaxial magnetic anisotropy having the circumferential direction as the easy axis and is magnetically polarized in a circumferential direction, said element having, when no torque is applied to said member, a circumferential magnetic orientation having only a circumferential component and, when a torque is applied to said member, a helical magnetic orientation having both circumferential and axial components, said transducer producing a magnetic field varying with the torque applied to said member.
Dependencies are inferred from the claim text.