| 摘要 |
<p>A magnetic measuring means for force measurement, in particular for measuring the traction resistance of an agricultural tractor. The means comprises a flexural bar (15), on both ends of which the force (F) to be measured acts, causing deflection of the bar (15). The flexural bar (15) is tubular and consists of material with good magnetic conductivity. Inside the flexural bar (15) is placed an iron core (23) which is in magnetic contact with the flexural bar (15). In conjunction with the iron core (23) are provided at least two series-connected exciting coils (27, 28). In the measuring air gap (25) of the iron core (23) is inserted a transducer element (26), such as a Hall transducer, detecting the magnetic flux density (B). The magnetic fluxes generated by the exciting coils (27, 28) are closed, on one hand, through the iron core (23) and its measuring air gap (25) and on the other hand through the opposed sides (15a, 15b) of the flexural bar (15), so that the magnetic flux on the tensile stress side increases and on the compressive stress side the magnetic flux correspondingly decreases. These changes of flux are indicated by the principle of magnetic bridge measurement, based on the changes of the flux passing through the measuring gap (25).</p> |
