| 摘要 |
A fail-safe torque transducer, and automotive power steering system, utilizing a two-stage series coupled torsion bar system. A first stage torsion bar provides tuning of the steering system, and by reducing its diameter relative to the second stage, provides a lower torsional spring rate and higher operational stress level than that of the second stage. The second stage torsion bar provides the stress/strain indicia referenced by a torque-measuring device, and is stressed at a lower level than the first stage and therefore has a higher cycle life than that of the first stage bar. Hence, if stress related failure ever occurs, it will only occur in the first stage torsion bar, thereby preventing any torque from reaching the second stage, thereby causing a zero strain signal and thus rendering the system fail-safe and not subject to instability of vehicle steering if the torsion bar breaks.
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