| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultra magnetostrictive actuator for generating sufficient output displacement with smooth operational movement despite a simple structure. SOLUTION: An ultra magnetostrictive actuator (A) for drive opening and closing of a valve body 27 in a fuel injection valve (I) has a first ultra magnetostrictive material 15, a joining member 17, and a second ultra magnetostrictive material 16 provided coaxially in a coil 14. The front end of the second ultra magnetostricitve material 16, with its rear end fitted to a guide member 19, is fitted to the front end of the joining member 17. The rear end of the joining member 17 is fitted to the rear end of the first ultra magnetostrictive material 15, and the front end of the first ultra magnetostrictive material 15 is put opposite to the rear end of the valve body 27 via a piston 20 inbetween. When the coil 14 generates a magnetic field, both the ultra magnetostrictive materials 15 and 16 are expanded and shrunk in the axial direction. The dislocation of the first ultra magnetostricive material 15 is transmitted to the second ultra magnetostrictive 16 with the joining member 17 inbetween, so that dislocation corresponding to the amount of expansion or shrinkage of both ultra magnetostrictive materials 15 and 16 is generated between the rear end of the first ultra magnetostrictive material 5 and the front end of the second ultra magnetostrictive material 16. |
