US 4,356,732 AGranted

Torque and torsion angle measuring apparatus

AssigneeRobert Bosch GmbH

InventorsHansjorg Hachtel, Klaus Dobler

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Abstract

Measuring apparatus for the torque transmitted through a shaft consists of a first and second induction member respectively mounted at the input and the output end of the shaft for rotation therewith. The induction members are discs or concentric cylindrical elements made of a conductive material, each member having sector-shaped cut-out portions. The sector-shaped cut-out portions of the two members are aligned for a predetermined starting torque. A coil is mounted opposite one of the members and generates a high frequency magnetic field. The magnetic field induces eddy currents in the members. The eddy currents in the second member increase as the conduction material of the second member shifts toward exposure to the coil through the cut-out portions of the first member. Increases in eddy currents cause decreases in inductivity of the coil which, when measured, constitute a measure of the transmitted torque.

Claims20

Dependent claims

Torque and torsion angle measuring apparatus comprising

a shaft (8) having an input end portion (7) and an output end portion (9);
a first induction member (2) concentric to said shaft and mounted on said input end portion for rotation therewith, said first induction member having electrically conductive portions (6) and electrically insulating portions (4);
a second induction member mounted on said output end portion for rotation relative to said first induction member, said second induction member having electrically conductive portions (3) and electrically insulating portions (5) overlapping corresponding portions of said first induction member to a predetermined extent prior to application of a torque to be measured;
a coil (1) at least approximately concentric to said shaft arranged in close proximity to said first and second induction members so that a magnetic field generated by said coil creates eddy currents in said second induction member varying in dependence upon the relative alignment of said electrically conductive portions of said first and second induction members, to effect a change in inductivity of said coil upon change in eddy currents to provide a measure of angular displacement of the input end portion to the output end portion of said shaft.

1 more element

Dependencies are inferred from the claim text.