Abstract: The vibration motor comprises adjoining working and feed-back piezoelectric cells, one of which is in contact with one of the stages of a concentrator of ultrasonic vibrations, whose other stage is pressed to one of the rotor surfaces. The working piezoelectric cell is connected with the output of an electric oscillator, the feed-back piezoelectric cell is coupled to the oscillator sync input. Provision is made in the vibration motor for a means for rotation frequency control of the rotor by changing the hold-down force pressing the driving stage of the concentrator of ultrasonic vibrations to the rotor surface and/or by maintaining the amplitude of ultrasonic vibrations of the driving stage of the concentrator at a preset level, or by varying the hold-down force of the driving stage of the concentrator of ultrasonic vibrations alongside with changing the amplitude of ultrasonic vibrations of the concentrator driving stage.

Abstract: The vibration motor comprises a concentrator of torsional vibrations, whose end face is in close contact with a rotor, and a piezoelectric cell unit adjoining the concentrator of torsional vibrations. Besides, the vibration motor is provided with a magnetic field source arranged under the rotor at the side of the concentrator of torsional vibrations and having a power sufficient to hold the rotor firmly against the concentrator end face, and with magnetic circuit. One part of the latter is movable, being fashioned as a disk with circumferentially spaced slots and rigidly connected to the rotor. The other part of the magnetic circuit separated from the first one by an air gap is stationary. It surrounds the magnetic field source and has peripheral slots identical to those of the movable disk and arranged opposite to them.

Abstract: The vibration motor of the invention comprises a concentrator of torsional vibrations including at least two stages. The first one of the stages takes up vibrations from a piezoelectric cell while the second stage contacts a rotor. The concentrator is provided with means for transforming piezoelectric cell vibrations into torsional ones, said means being fashioned as rods provided on the side surface of the first stage. The rods are located in a plane normal to the concentrator axis and inclined each at an acute angle to a tangent at the point where the rod is attached to the line of intersection of the side surface of the first stage with said plane. The rods serve as resonators of longitudinal vibrations propagating therein.