RU2424611C1 - Noncontact electric motor - Google Patents

Abstract

FIELD: electricity. ^ SUBSTANCE: noncontact electric motor includes hollow cylindrical nonmagnetic slotless stator with winding, which is arranged between parts of composite rotor. Outer part of rotor is made in the form of ferromagnetic shell, and inner part is made in the form of cylindrical constant magnet fixed on shaft in bearings. The latter are arranged in support sleeves of stator ends, which can be made from heat-resistant dielectric material. ^ EFFECT: improving positioning accuracy of rotor axis and improving reliability of proposed noncontact electric motor at simultaneous simplification of its design and manufacturing procedure, reduction of weight, dimensions and manufacturing costs. ^ 2 cl, 1 dwg

Description

The invention relates to the field of electrical engineering, namely to electrical machines with non-contact switching, carried out using semiconductor elements, and can be used in high-speed DC motors for small electric drives, for example in instrumentation, dental technology, power tools with increased requirements for energy performance and dynamic acceleration and braking performance.

A known electric machine for creating a magnetic field, which is a separate unit consisting of a hollow cylinder with flanges at the ends, made of non-magnetic material, in the radially through grooves of which on the outer side, cores made of magnetic material are fixed ring-like, with a certain step , serving as a magnetic circuit, a winding is placed in the space between the cores; prevention of falling out of the winding is provided by clamping strips made of non-magnetic material that is attached to the end flanges. A device for converting one type of energy into another consists of two rotors, one of the rotors being installed inside the device for creating a magnetic field and interacting with its internal part, the other rotor covering the external part of the device for creating a magnetic field and interacting with it (RU patent description 2360352 IPC H02K 16/02 (2006.01) H02K 1/16 (2006.01) H02K 17/00 (2006.01).

The presence of cores in a known design creates additional losses in steel, as well as higher harmonics of the magnetic field. An all-metal casing made of non-magnetic material causes power loss from eddy currents. All this reduces the efficiency of the machine.

In addition, due to the large difference in the linear expansion coefficients of the housing material and bearings, the occurrence of unacceptable clearances or interference is inevitable during assembly. In this case, the axes of the bearings shift, the appearance of an eccentricity between the rotating and stationary parts. Additional mechanical losses in bearings and unilateral magnetic attraction forces appear. Such phenomena lead to a decrease in the service life of the machine and are completely unacceptable for high-speed electric motors with increased weight and size requirements.

A non-contact synchronous machine is known, including a stator, which is a non-ferromagnetic cylinder formed from copper windings of a baseless design and cast with a special composition with high thermal conductivity. The stator is placed between the cylindrical surfaces of the inner and outer parts of the rotor, made of ferromagnetic material, and containing permanent magnets facing the stator and mounted on the outer part of the rotor. The rotor is mounted on the shaft in bearings mounted in the motor housing from the ends (the description of patent RU 2374743 H02K 21/12 (2006.01) H02K 21/22 (2006.01) H02K 16/02 (2006.01).

In the known device, the statorless execution of the stator eliminates the problem of power losses in the teeth and losses from higher harmonics of the magnetic field.

Significant disadvantages of the known device are the complexity of the construction of the composite rotor, the presence of an external casing, which duplicates the functions of the stator and is an additional magnetic circuit; cantilever mounting of the stator winding, which requires an additional centering mandrel for gluing it; placement of shaft bearings in non-metallic bushings of the housing, which reduces positioning accuracy during assembly. All these factors complicate the technology of manufacturing an electric motor, overestimate its dimensions and weight, complicate operation.

The objective of the invention is to simplify the design and manufacturing technology, improve the operational characteristics of a non-contact synchronous motor with one stator and two rotors.

The technical result of the invention is to increase the accuracy of the positioning of the axis of the rotor and reliability, reducing weight, dimensions and the cost of manufacturing an engine.

The technical result is achieved by the fact that in a non-contact electric motor including a hollow cylindrical non-magnetic baseless stator with a winding located between the parts of the composite rotor with a permanent magnet, of which the outer part is made in the form of a ferromagnetic cup mounted on a shaft in bearings, the latter are placed in the bearing bushings of the ends stator, and a permanent cylindrical magnet is fixed on the shaft, forming the inner part of the rotor. In this case, the support sleeve can be made of heat-resistant dielectric material.

The contactless synchronous motor is schematically represented in the drawing.

The motor contains a hollow cylindrical non-magnetic stator 1 with a multiphase winding wound on a baseless mandrel, placed coaxially between the separate parts of the composite rotor — the outer one in the form of a ferromagnetic cup and the inner one in the form of a radially magnetized permanent cylindrical magnet 3. The stator winding 1 is placed in the gap between the inner surface of the ferromagnetic cup 2 and the outer surface of the permanent magnet 3, which are fixed on the shaft 4 in the radial ball bearings 5, 6.

The ends of the stator 1 and the radial ball bearings 5, 6 are installed respectively in the support sleeves 7, 8, made, for example, of a heat-resistant dielectric material. The bearing 5 on the shaft 4 and the support sleeve 7 are placed inside the ferromagnetic cup 2.

The sleeve 8 is made in the form of a bearing shield and holes (not shown) are provided in it for outputting the ends 9 of the winding connection.

The fixation of the stator 1 in the support sleeves 7, 8 from opposite ends increases the rigidity of its structure, and the placement of the shaft bearings 4 in them allows to exclude the bearing body part from the structure. Elimination of the bearing housing reduces the dimensions and weight of the machine, reduces the number of structural elements, eliminates power losses from the braking moments created by the scattering fields from the outer surface of the outer part of the rotor.

When connecting the ends of the winding 9 to the transducer with semiconductor devices, a rotating magnetic field occurs. When the magnetic field of the stator winding 1 interacts with the field of the permanent magnet 3, a torque arises, causing the rotor to rotate. It is also possible to operate the motor in generator mode.

Claims (2)

1. A non-contact electric motor, including a hollow cylindrical non-magnetic baseless stator with a winding, located between the parts of the composite rotor with a permanent magnet, of which the outer part is made in the form of a ferromagnetic cup mounted on a shaft in bearings, characterized in that the latter are placed in the supporting bushings of the ends of the stator and a permanent magnet is fixed on the shaft, forming the inner part of the rotor. 2. The electric motor according to claim 1, characterized in that the support sleeve is made of heat-resistant dielectric material.