| 摘要 |
Torque is measured in the chain wheel ( 50 ) of a pedal cycle by a non-contacting magnetic-based transducer. A magnetising source ( 70 ), a D.C. type of source such as a permanent magnet is positioned adjacent the chain wheel ( 50 ) to induce an arcuate magnetised zone ( 72 ) in the wheel ( 50 ) as it rotates. The zone emanates a torque-dependent magnetic-field component that is detectable by a sensor ( 74 ) that follows the source ( 70 ) in the direction of rotation. By having the magnetising source ( 70 ) continually in position the arcuate tranducer zone ( 72 ) is refreshed on each rotation of the chain wheel. The nature of the pulsating torque in the chain wheel due to the exertion of the rider and its relationship to the angle of the pedal cranks is discussed with a preference for positioning the source ( 70 ) and sensor ( 74 ) at positions of minimum and maximum exerted torque respectively. If the induced arcuate magnetisation is interrupted ( 76 ) pulses for measuring rotational speed are obtainable. The torque measurement is of general application to torque in sprocket wheels or gear wheels.
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