| 主权项 |
1. Ultrasonic motor, comprising an ultrasound actuator having the form of a piezoelectric hollow cylinder comprising an inner circumferential surface and an outer circumferential surface as well as end faces connecting the inner and outer circumferential surfaces to each other, where friction elements are disposed on at least one end face, a rotor in effective contact with the friction elements comprising at least one disc or one platform, and an electric excitation device, wherein the ultrasound actuator is subdivided in the circumferential direction into an even number of sectors Sa and Sb having a mean length L of a sector in the circumferential direction, a height H of a sector in the axial direction and a thickness T of a sector in the radial direction, and respective two sectors Sa and Sb form a first sector group A and a second sector group B, wherein the sectors Sa and Sb of the respective two adjacent sector groups A and B alternate and are adjacent to each other, wherein in the region of the adjacent arrangement of neighboring sector groups A and B the friction elements are disposed, wherein each of the sectors Sa and Sb is formed by excitation electrodes and general electrodes arranged alternatingly in the axial direction of the hollow cylinder, wherein one layer of piezoelectric material is arranged between neighboring excitation electrodes and general electrodes, and wherein all the excitation electrodes which are related to the first sector group A are electrically connected to each other and to a first output of the electrodes to the electric excitation device, and all the excitation electrodes which are related to the second sector group B are electrically connected to each other and to a second output of the electrodes to the electric excitation device, and all the general electrodes of the ultrasound actuator are electrically connected to each other via connections to a third output to the electric excitation device, wherein the excitation electrodes and the general electrodes and the layers of piezoelectric material arranged between neighboring excitation electrodes and general electrodes of the sectors of a group of sectors form a generator for acoustic longitudinal standing waves, and the generators thus formed are electrically drivable such that a first longitudinal standing wave expands along a generatrix and thus along the circumferential direction of the ultrasound actuator, and a second longitudinal standing wave expands along the height of the ultrasound actuator. |
