JPS60211120A - Magnetic bearing - Google Patents

Abstract

PURPOSE:To enable reliable operation by supporting a rotor in a floating manner at a position free from an influence of repulsive force of a small-area magnet, repulsive force and attraction of the end portion of a large-area magnet to which attraction faces in a magnetic bearing. CONSTITUTION:The area of a cylindrical magnet 16 that confronts with a cylindrical magnet 18 disposed on a support 8 is very smaller than the opposite area of the magnet 18. Therefore, the repulsive force and attraction are not reversed, so that floating rotation can be accomplished stably and smoothly by a pair of magnets 16, 18, and smooth rotation of a rotary shaft or a rotor can be maintained without providing a position detector separately.

Description

[Detailed description of the invention] The invention of this application relates to a magnetic bearing.

Especially the repulsive force of magnets as bearings that support rotating bodies.
This invention relates to improvements in magnetic bearings that levitate and support rotating bodies using

This type of magnetic bearing, which has been used in the past, is
It has the configuration shown in the figure, and the repulsive force (repulsive force) of the magnet
By applying this method, a pair of magnets are placed facing each other in order to levitate and support the rotating body, thereby preventing wear on the bearings and completely preventing the generation of frictional torque.

The configuration of the bearing 1 is as follows.

The rotating shaft 2 is orthogonal to a pair of support plates 4.6 provided horizontally in a case (not shown), and is rotatably supported by these support plates. 811?:
Another cylindrical magnet 10 having a U-shaped cross section is mounted so as to face the cylindrical magnet 12 provided. The pair of magnets 10 and 12 have approximately the same radius and have opposing surfaces magnetized with the same polarity, and in this embodiment,
The opposing surfaces are magnetized so as to form S poles, and the other non-opposing surfaces form N poles. Further, a rotating body 14 is mounted on the rotating shaft 2 between the support plate 4.6 and the rotating body 14 so as to be rotatable together with the shaft.

When the rotary body 14 is supported by the support plate 4.6 together with the rotary shaft 2 and rotates in a predetermined direction, the same polarity sH of the magnet 10 attached to the end of the rotary shaft 2 and the magnet 12 provided on the support base 8 is generated. This repulsive force (or repulsive force) causes the rotating shaft 2 to
floats to form a predetermined gap between the magnets 12 and 10, and the weight of the rotating body 14 and rotating shaft 2 is supported by the repulsive force of both magnets. can rotate smoothly.

However, in the bearing having the configuration of the conventional example, if an external force acts and the specified position of the rotating shaft 2 on which the rotating body 14 is mounted is misaligned, for example, the rotating shaft 2 may shift slightly from the center to one side. Even in the case of displacement, the distance between the same poles of the magnets 10, 12 becomes human, and the distance between the -cutting tool poles becomes closer to each other. However, the magnitude of the attractive force or repulsive force (repulsive force) acting between two magnetic poles is in accordance with Coulomb's law and is inversely proportional to the square of the distance. The repulsive force (repulsion) of the poles becomes weaker and weaker, and on the contrary, the attractive force between the S and N poles of the different poles becomes stronger and stronger, and eventually they are completely displaced to one side, so the rotating shaft 2 and the rotating body rotate 140 times There were deficiencies such as the process not being carried out smoothly.

Therefore, various efforts have been made to overcome this problem, but there are also methods that employ a complicated control device. For example, methods have been implemented in which displacement is electrically detected with a position detection device and the current of an electromagnet is controlled to maintain a stable bearing position. These methods have drawbacks such as the need to separately provide complicated equipment.

The purpose of the invention of this application is to eliminate these drawbacks, and it is possible to achieve the purpose by making simple improvements to conventional magnets without requiring any special equipment. I did it.

An embodiment of the present invention will be described below with reference to the accompanying drawings FIGS. 2 and 3. FIG. 2 shows a modified pair of opposing magnets 16.1'8'i. The area of the side facing the cylindrical magnet 18 provided on the support base 8 of the cylindrical magnet 16 having a U-shaped cross section and fixedly inserted into the end of the rotating shaft 2 is extremely smaller than the area facing the magnet 18. Then the cylindrical magnet 18
The area x9 of the magnet 16 of the rotating shaft 2 is also extremely large, and both magnets are arranged facing each other.

In the configuration in which magnets with different areas are arranged opposite each other as described above, even if the rotating shaft 2 and the magnet 16 are displaced by an external force, the repulsive force (repulsive force) between the same poles will be slightly weakened, but the repulsive force between the same poles will be slightly weakened, but the The attraction between them does not become too strong. FIG. 3 is a route map illustrating the above situation. The point perpendicular to the vertical axis and the horizontal axis t is O, and the repulsive force R is above the point 0, and the attractive force is below O (9).The resultant force of the repulsive force and the attractive force of the magnet is shown as the repulsive force according to the present invention. The resultant force between the repulsive force and the attractive force can be shown by the phase image line a, and the resultant force between the repulsive force and the attractive force in the conventional structure can be shown by the phase image line a. Symbol C indicates a gap between a pair of facing magnets.

Is the horizontal axis t a section of repulsive force R and attractive force A? If it were to be displayed, it would be clear that the phase image line showing the resultant force of the repulsive force and the attractive force in the conventional example shows that the force is reversed at the intersection point P of the horizontal axis line t and the resultant force. On the other hand, in the configuration according to the present invention, since the resultant force aU does not intersect with the horizontal axis t, stable floating rotation by the facing magnets can be performed without reversal of the force.

As mentioned above, in the present invention, unlike the conventional configuration, even when the bearing is displaced due to external force,
Since the repulsion (repulsive force) and the attractive force do not reverse as in the conventional example, the floating rotation by the pair of magnets 16°18 is stable.
It can be carried out smoothly, there is no need to provide a separate position detection device, and there are advantages such as being able to maintain smooth rotation of the rotating shaft and rotating body with a simple configuration.

The present description mainly relates to embodiments of bearings in which the magnets are permanent magnets. Of course, electromagnets can be used instead of permanent magnets.

Further, although the embodiments of the present invention relate to bearings installed vertically, the same principle applies to bearings installed laterally, i.e. horizontally. l
Of course, the same purpose and effect can be achieved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the main components of a conventional bearing. FIG. 2 is a sectional view of a pair of magnets employed in the present invention. FIG. 3 is a route diagram comparing the combination of repulsion and attraction of a conventional magnet and the combination of repulsion and attraction of a magnet according to the present invention. 1...Bearing 2...Rotating shaft 4...Support plate 6...Support plate 8...Support stand 10...Magnet 12...Magnet 14...Rotating body 16...Magnet ( Vertical axis] 18...Magnet (support stand) Patent applicant Konoki Electronics Co., Ltd. Agent Patent attorney Sakae Kobayashi Figure 2

Claims (1)

[Claims] 1. In a bearing that levitates and supports a rotating body by the repulsive force of magnets, one of the mutually repulsive surfaces of a pair of magnets facing each other is treated with a small surface area The rotating body is supported by floating at a position where the repulsive force and attractive force of the magnet having a small area are not affected by the repulsive force and attractive force of the facing end of the magnet having a large area. magnetic bearing. 2. Claim 1, which comprises a magnet attached to the end of the rotating shaft and having a small-area repulsive surface, and a magnet having a large-area repulsive surface provided on a support stand opposite thereto. Magnetic bearings as described in section.