| US 7,506,554 B2 | ||
| Magnetostrictive torque sensor system and electric steering system | ||
| Yasuo Shimizu, Shimotsuke (Japan); Yoshito Nakamura, Kawachi-gun (Japan); Shunichiro Sueyoshi, Shioya-gun (Japan); and Atsuhiko Yoneda, Utsunomiya (Japan) | ||
| Assigned to Honda Motor Co., Ltd., Tokyo (Japan) | ||
| Filed on Jun. 13, 2007, as Appl. No. 11/818,071. | ||
| Application 11/818071 is a continuation in part of application No. 11/199914, filed on Aug. 09, 2005, abandoned. | ||
| Claims priority of application No. 2004-245124 (JP), filed on Aug. 25, 2004; and application No. 2006-096584 (JP), filed on Mar. 31, 2006. | ||
| Prior Publication US 2007/0240522 A1, Oct. 18, 2007 | ||
| Int. Cl. G01L 3/00 (2006.01) | ||
| U.S. Cl. 73—862.331 | 7 Claims |
| 1. A magnetostrictive torque sensor system, comprising:
a magnetostrictive torque sensor including:
a first magnetostrictive film and a second magnetostrictive film, which are provided at a shaft and have different magnetic
anisotropies;
a first measurement coil and a second measurement coil which face the first magnetostrictive film; and
a third measurement coil and a fourth measurement coil which face the second magnetostrictive film, wherein:
a torque applied to the shaft is measured based on a variation in magnetic characteristics of the first and the second magnetostrictive
films; and
an electronic control unit including a device for detecting a failure of the magnetostrictive torque sensor is detected based
on the sum of a first difference between output values from the first and the second measurement coils and a second difference
between output values from the third and the fourth measurement coils.
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