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US 5,520,059 AGranted
Circularly magnetized non-contact torque sensor and method for measuring torque using same
AssigneeMagnetoelastic Devices, Inc.
InventorIvan J. Garshelis
Life of this patent
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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 one 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 therting. 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 in a fixed position relative to the ring and oriented so that it responds maximally only to the field due to the axial magnetization 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. In another embodiment, the magnetoelastically active portion includes two or more axially distinct, magnetically contiguous, oppositely polarized circumferential regions. The regions may comprise physically separate rings or may be formed onto a single ring.
A magnetoelastic torque sensor for providing an output signal indicative of the torque applied to a member about an axially extending axis, of said member, comprising:
A method of sensing a torque applied to a torqued member extending in an axial direction, comprising the steps of:
A transducing ring adapted to be attached directly or indirectly on the surface of a member to which a torque is applied about an axis extending axially thereof in such a manner that torque applied to said member is proportionally transmitted to said ring, said ring comprising a magnetoelastically active element which is endowed with an effective uniaxial magnetic anisotropy having the circumferential direction as the easy axis, said element comprising two or more axially distinct, magnetically contiguous circumferential regions which are oppositely magnetically polarized in the circumferential direction and 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 method of producing a magnetoelastic torque transducer for attachment to a member to which an axial torque is applied, comprising the steps of:
Dependencies are inferred from the claim text.