| 摘要 |
PROBLEM TO BE SOLVED: To provide a torque detecting mechanism capable of highly accurately detecting the size and direction of torque acting on a rotary shaft. SOLUTION: A torque detecting mechanism 210 includes: a rotary shaft 140 coupled to a steering wheel (not shown) via a steering shaft (not shown) and a swivel joint; a first bearing 211 rotatably supporting a lower end 140a of the rotary shaft 140; a second bearing 212 rotatably supporting a central portion 140c of the rotary shaft 140; exciting circuits 213A and 213B for exciting magnetostrictive films 142A and 142B by applying AC voltages to the magnetostrictive films 142A and 142B, respectively; and detecting circuits 214A and 214B for electrically detecting changes in magnetic permeability of the magnetostrictive films 142A and 142B, respectively. The rotary shaft 140 has an upper end 140b that is not supported unlike the lower end 140a and central portion 140c respectively supported by the bearings 211 and 212. That is, the upper end 140b is a free end. Moreover, the thickness of each magnetostrictive film is not more than 30μm. COPYRIGHT: (C)2008,JPO&INPIT
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