JPS5842824A - Eddy current reduction armature disk - Google Patents

Abstract

PURPOSE:To reduce an eddy current loss as well as a windage loss by laminating electromagnetic steel plates with slits so as to place a steel plate with no slit on the uppermost face and lowermost face. CONSTITUTION:(a) is a disk with no slit and (b) is a disk with radial and uniformly spaced slits. One disk (a) is placed at the top and bottom each, and suitable number of disks (b) for the required thickness are stacked and individual disks are displaced from the next one by a uniform angle so that the total displacement is equal to or a multiple of an angle between adjoining slits, then all of them are laminated in one body. Thus, no groove is formed on the disk surface, thereby the windage loss can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an armature disk for an axial electromagnet in a magnetic bearing for high-speed rotation. It is.

Conventionally, in magnetic bearings aimed at high speed rotation and high response, the armature disk for axial electromagnets is shown in Figure 1.
The features of this armature disk, which has been proposed as shown in Figure 1, are that radial grooves are placed in the disk to reduce eddy currents caused by changes in magnetic flux density in the axial direction, thereby reducing drag torque in the rotational direction. The purpose is also to improve responsiveness.

However, this armature disk has the following drawbacks.

1) Because there are grooves on the upper and lower surfaces of the armature disk, large windage losses occur during high-speed rotation.

2) There are grooves on the upper and lower surfaces of the armature disc, which causes uneven suction force in the axial direction.

3) The number of grooves cannot be increased unnecessarily due to processing problems.

The present invention aims to eliminate the above-mentioned drawbacks.

The outline of its configuration is shown in Figure 3, as shown in Figure 2.
The apparatus is a disc without slits, which is composed of steel plates ex and b of different types, and b is a disc with slits made radially and at equal intervals. Shift the slit position by an equal angle for each board by an appropriate amount so that the A board and the B board have the required thickness. ``The whole thing is laminated and integrated.''

The features of this armature disc are that there are no grooves on the disc surface, which can significantly reduce windage loss compared to conventional discs, and because it has a structure in which slits are made in the steel plate, it can be manufactured by etching or punching. Therefore, the number of slits can be easily increased compared to the conventional method, and mass production is also possible. In addition, by shifting the slit positions at equal intervals, the unevenness of the attraction force is reduced, and because of the laminated structure of steel plates, it is extremely effective in reducing eddy currents due to changes in magnetic flux density not only in the axial direction but also in the radial direction. has. Here, the eddy current flowing through the upper and lower steel plates that do not have slits to reduce windage damage will be considerably smaller if the steel plates are made thinner, but they are larger than those with slits.

Therefore, in order to eliminate this effect, it is necessary to use thin insulating plates (polyimide plates, etc.) instead of the upper and lower steel plates, or to fill the slits of the steel plates with insulating material (epoxy resin, etc.) and flatten the surface of the steel plates. Methods such as excluding α are also effective.

[Brief explanation of drawings]

Figures 1 and B are a side view and a front view of a conventional armature disk, Figures 2A and B are a side view and a front view of an embodiment of the present invention, and Figure 3 is a slope view. ...Disc without slits b...Disc with equally spaced slits or more Applicant Daini Seikosha Co., Ltd. Agent Patent attorney Tsutomu Mogami

Claims (1)

[Claims] Electromagnetic steel plates with slits are stacked, and the top and bottom surfaces are made of steel plates without slits, or thin insulating plates (such as polymide plates), or the slits are covered with insulators (such as engineered mexi resin, etc.). ) is embedded to make the surface flat, and the armature disk for an axial electromagnet is characterized by stacking steel plates with the slit positions shifted.