Other

Dalian University of Technology

Yuanxiu Wang

Xiaoming Wang

Yulin Mei

Yixuan Mei

The present invention belongs to the technical field of alternating current induction servo motors, and particularly relates to a rotary-type induction servo motor with a constant-output-torque by using uniform magnetic fields and a linear-type induction servo motor with a constant-output-force by using uniform magnetic fields. The present invention has main features that the rotary-type induction servo motor or the linear-type induction servo motor is composed of N independent motor units; each independent motor unit has the same or similar structure, and is powered by single-phase alternating current; and the N independent motor units have an equal voltage magnitude of power supply, but voltage phases are different and form an arithmetic progression. In an independent motor unit of the rotary-type induction servo motor with a constant-output-torque by using uniform magnetic fields, the stator magnetic conductive silicon steel is simple in structure, and the winding manner of stator excitation windings is simple, similar to a multilayer solenoid type; rotor induction excitation windings are powered through induction, and no slip ring and related wearing parts are used. The rotary-type induction servo motor disclosed here can be operated at fixed voltage frequency, and in this case, the output torque and the voltage magnitude of power supply are in direct proportion, so the output torque can be controlled by adjusting the voltage magnitude. The motor does not adopt permanent magnetic materials, and has many merits including simple structure, good torque characteristic, simple controller design and high control precision. And meanwhile, based on the same principle, a linear-type induction servo motor with a constant-output-force by using uniform magnetic fields can be evolved from the rotary-type induction servo motor.

Induction servo motor with a constant-output-force or a constant-output-torque by using uniform magnetic fields

The present invention discloses a ultrathin acoustic impedance converter belonging to the acoustic field, which is characterized by comprising one or a plurality of impedance conversion units, wherein each impedance conversion unit is composed of a frame, a plurality of prestressed membranes or prestressed string nets, and multiple layers of acoustic materials, wherein a through cavity is fabricated in the frame, the prestressed membranes or string nets and the acoustic materials are alternately arranged in the cavity, i.e., a prestressed membrane or string net is arranged, and then a layer of acoustic materials is arranged, and so on until the through cavity is fully filled. The cavity can be designed in different shapes either with a variable cross section or a uniform cross section. Each prestressed membrane or string net is required to be applied with prestress before being arranged in the cavity, and the magnitude of the prestress depends on the acoustic impedance value that the membrane or string net is expected to reach. The novel ultrathin acoustic impedance converter of the present invention can realize rapid change from low impedance to high impedance or from high impedance to low impedance and realize ultrathin design.

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Liaoning, China

Yuanxiu Wang