Selection manner of the Drive device and its production manner and the grease for the Drive device which use the electric machine sensing element

摘要

P To substantially eliminate a decrease in a movement speed of an engagement member caused by a repetition of a reciprocating drive over time and also to substantially eliminate a decrease in an upper limit of the movement speed of the engagement member in a low-temperature environment. PSOLUTION: A driver is provided with: an electromechanical conversion element 15; a driving friction member 17 fixed to one end of the electromechanical conversion element 15 in the extending and contracting directions; and the engagement member 11 engaged with the driving friction member by a friction force and the driver relatively moves the driving friction member 17 and the engagement member 11. A voltage is applied to the electromechanical conversion element 15 at a frequency of 10-300 kHz. A grease having a base oil kinematic viscosity of 300 mmSP2/SP/s or less at a temperature of 0° C is applied to an engagement section between driving friction member 17 and the engagement member 11. PCOPYRIGHT: (C)2007 and JPO& INPIT