JP2006014555A - Noise reduction structure for electromagnetic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noises due to magnetic excitation oscillation in an electromagnetic apparatus that uses electromagnetic steel plates. <P>SOLUTION: A damping steel sheet is disposed among groups of iron cores consisting of several pieces of electromagnetic steel plates, magnetic excitation oscillation due to the fluctuation of flux is damped, and reduction in noise to the outside is expedited by making the iron cores a small group and making the resonance frequency of the iron cores to be further higher. For example, in an example of a basket-shaped induction motor, the iron cores are made into small blocks by the damping steel sheet 6 or 7 to shift the resonance frequency of the iron core portions to the high-frequency side, and synergism to the noise reduction can be obtained by damping the magnetic excitation oscillation between the electromagnetic steel plates by oscillation damping forces of the damping steel sheets themselves. Furthermore, not only the induction motor but also electromagnetic apparatuses, such as transformer and reactor having the iron cores, the similar effect can be obtained by disposing the damping steel sheets at the iron cores. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reduction in noise generated in an electromagnetic device using an electromagnetic steel sheet.

In equipment using electromagnetic force or electromagnetic induction represented by motors, generators, transformers, reactors, etc., the same kind of electrical steel sheets is laminated to reduce eddy current loss caused by changes in magnetic flux passing through the iron core. It is used.

  However, these devices have a drawback that magnetic excitation vibration is generated between the magnetic steel sheets due to the change of magnetic flux, which is generated as noise outside.

  In particular, this drawback is a major obstacle in electrical equipment used for customer service such as electric railways.

In order to improve the adhesion between magnetic steel sheets, measures such as tightening with bolts or the like from both ends of the iron core, or adhering the steel sheets by resin impregnation, etc., are adopted as measures for improvement. Is currently connected, but has not led to a significant reduction. (For example, refer to Patent Document 1).
JP 2004-055787 A

The problem to be solved is that the magnetic excitation vibration between the electrical steel sheets generated by the change of the magnetic flux is not absorbed at all and becomes a noise generation source to the outside.

The main feature of the present invention is to reduce the generated noise by sandwiching a damping steel plate every several electromagnetic steel plates and absorbing vibrations at the damping steel plate portion.

  The present invention has an advantage that generated noise can be reduced without greatly changing the basic structure of the device.

  The structure can be achieved only by replacing several electromagnetic steel plates with damping steel plates, and the basic structure of the target device is not greatly changed.

FIG. 1 is a simplified cross-sectional view of one embodiment of the structure of the present invention for an induction motor, where 1 is a stator core electromagnetic steel sheet, 2 is a rotor iron core electromagnetic steel sheet, 3 is a stator coil, and 4 is a rotor. Bar 5 is a frame,
6 is a stator core damping steel plate, 7 is a rotor core damping steel plate, 8 is a stator core presser, 9 is a rotor core presser, and 10 is an end ring.

  5. Stator core damping steel plate And rotor core damping steel plate 7. Are the stator iron core electrical steel sheets. And rotor core magnetic steel sheet 2. It is arranged between several cores and is composed of one or a relatively small number.

  This example shows an example of a squirrel-cage induction motor, but the rotating magnetic field generated on the stator side and the rotating magnetic field cut the rotor coil portion formed by the rotor bar 4 and the end ring 10. The rotating force is obtained in relation to the generated magnetic field. And rotor core magnetic steel sheet 2. The magnetic flux flowing through the iron core assembly composed of fluctuates greatly.

Therefore, a striking phenomenon due to attraction and repulsion occurs between the magnetic steel sheets. When this frequency coincides with the resonance frequency of the iron core portion, a large noise is generated to the outside.

  However, in this structure, the iron core is a damping steel plate. Or 7. It is possible to shift the resonance frequency of the iron core part to the high frequency side and absorb the magnetic excitation vibration between the electromagnetic steel plates by the vibration absorption force by the damping steel plate itself. can get.

  Although the above embodiment relates to an induction motor, the same effect can be obtained by arranging a damping steel plate in the core portion of an electromagnetic device such as a transformer or a reactor having an iron core.

FIG. 1 is a simplified cross-sectional view of one embodiment of the structure of the present invention intended for an induction motor.

Explanation of symbols

1 Stator Core Magnetic Steel Sheet 2 Rotor Core Magnetic Steel Sheet 3 Stator Coil 4 Rotor Bar 5 Frame 6 Stator Core Damping Steel Sheet 7 Rotor Core Damping Steel Sheet 8 Stator Core Presser 9 Rotor Core Presser 10 End Ring

Claims (1)

In electrical equipment that uses electrical steel sheets, an equipment structure that aims to reduce externally generated noise by absorbing magnetic excitation vibration by interposing damping steel plates partially between the electrical steel sheets.

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