| 摘要 |
PURPOSE:To produce approximately linear motion with optimal force and speed directly from a motor by employing a linear ultrasonic motor, as the drive source for an elevation angle unit, in a bed comprising a bed support, a bed body, and the elevation angle unit for adjusting the elevation angle of the bed body. CONSTITUTION:Upon application of an AC voltage of frequency (f) onto a first piezoelectric body 22, a resilient body 21 resonates in secondary bending mode thus exciting a standing wave. Upon application of the AC voltage of frequency (f) onto second piezoelectric bodies 23a, 23b, the resilient body 21 resonates in primary longitudinal oscillation mode thus exciting a standing wave. An approximately elliptical oscillation of arbitrary shape can be produced in the resilient body 21 by regulating the amplitude and the phase of the voltage to be applied. Consequently, frictional force between a driving section 32, arranged in a ultrasonic motor 7, and a rail 6 produces driving force for driving the ultrasonic motor 7 on the rail 6 in predetermined direction, and the elevation angle of bed frame body 8 can be regulated by means of mounting frames 2b, 2c. |
