| 摘要 |
PURPOSE:To enable a wave stepping motor to make desired stable stepping drive by separating the projecting sections of a stator attached with a piezoelectric element and provided with the projecting sections which are brought into contact with a rotor from vibrating nodes and, at the same time, counterposing the projecting sections to the vibrating nodes. CONSTITUTION:An annular piezoelectric element 3 is attached to a stator 1 and ultrasonic vibrations are induced in the thickness direction by applying a voltage across the element 3 through a pattern. The stator 1 is provided with projecting sections 11 for enlarging the vibrational displacement of the stator 1 in the circumferential direction and a rotor 2 is provided with projecting sections 22, 23, 24, and 25 for bringing the projecting sections into contact with the stator 1 at the antinode of the vibrations. When the pattern is split into 12 parts and the split parts are grouped into four groups of three adjacent parts and the rotor 2 is driven, with the opposite groups in the same phase and adjacent groups in opposite phases, 2-lambda vibrations are caused in the thickness direction and the projecting sections 22, 23, 24, and 25 of the rotor 2 move to positions of nodes 112-114 near the sections 23, 24, and 25. When the rotor 2 is then driven by shifting the combination of the driven pattern by one, the nodes 121 and 124 are formed and the rotor 2 is driven in steps. |
