JPH03213717A - Magnetic bearing - Google Patents

Abstract

PURPOSE:To maintain a rotary shaft in the floating state without power consumption by forming a permanent magnet, which is to be a movable part, into the shape similar to an abacus bead, and interposing this permanent magnet between two permanent magnets with inner conical faces thereof respectively parallel to both outer conical faces of the movable permanent magnet. CONSTITUTION:A rotor 1 is supported rotatably around a rotary shaft. A movable magnet 5 is formed into the shape of an abacus bead with its outer edge part cut. Fixed magnets 4, 4' are disposed with a gap held parallel to their inner conical faces by magnetic resiliency so as not to be in contact. This gap is regulated by housings 7, 7' into the optimum position. The rotation axis can be thus maintained in the magnetically floating state from its supporting body without power consumption.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is applied to permanent magnets, which have the same field of application as radial bearings for the purpose of reducing friction and wear in moving parts of machinery. This relates to a magnetic bearing that uses only the repulsion of magnetic poles.

[Prior Art] Unlike mechanical bearings such as rolling bearings and sliding bearings, 6R air bearings can hold rotating bodies without contact. In other words, it has the characteristic that it can completely eliminate the effects of frictional resistance, wear, noise, etc. caused by oil films, gas films, or contact between metals, and has a semi-permanent lifespan. Therefore, various FFL bearings have been developed as bearings that support high-speed rotating shafts. In general, the structure of magnetic bearings is classified into two types: those using a combination of permanent lithium-ion stones and electromagnets, and those using only permanent magnets. The former is equipped with a sensor that detects position changes, and has a structure in which the position detection signal is used to feedback control the strength of the LiR stone and levitate the rotating body to a fixed position. The latter type of magnetic bearing uses the repulsion of 66 permanent magnets with the same poles and the attraction of 6R of different poles to magnetically hold the rotating body (♀ balls) without consuming power. ing.

[Problem to be Solved by the Invention 1] However, the l1f1 air bearing with a structure using the above-mentioned electric stone is a high-grade and complicated bearing that uses a position detection sensor and a control position, and is also very large in shape. The first problem is that the power consumption is large.

Next, the problem with conventional magnetic bearings made only of permanent magnets is that the position of the rotating shaft in the axial and radial directions is restricted due to insufficient consideration of the flow of the 6R bundle line due to the shape and arrangement of the Knite stones. There is a second problem, divination, in which the stability of the object becomes incomplete, unless a mechanical guide is added to regulate it. That is, in many cases, a completely non-contact state cannot be achieved. Of course, an example in which non-contact is maintained is disclosed in Japanese Patent Application Laid-Open No. 50-50530. By adjusting the positional relationship between the bearings, the gap due to the repulsive force of the first-sleeve bearing can also be adjusted, and assembly requires time, effort, skill, or experience. As a conventional example, FIG. 3 shows a sectional view of a 6f1 air bearing consisting of one rotating body and two bearings. Here, 1 is a rotating body, 2 is a rotating shaft, 3 is a neck of the rotating shaft for locking the movable part magnet 5, and 4 is a fixed part magnet. In this configuration,
If parts 1, 2, and 3 on the rotating body side are not present, the part 5 will obviously jump out from the position shown in the figure in the direction of arrow C due to mutual repulsion, and will not be maintained in the form of a bearing.

Therefore, in order to assemble as shown in this figure, the rotating body must first be prepared, and then 5 must be pulled into the bearing position against the repulsive force 4 and adjusted and fixed. This method is much more complicated than the method using so-called mechanical radial bearings, and poses a third problem for users. The present invention eliminates these drawbacks and can be used in the same way as conventional radial bearings.
The present invention aims to provide a magnetic bearing made only of permanent magnets that can be used reliably.

[Means for Solving the Problems 1] Since the Eft air bearing configured according to the present invention utilizes only the repulsive force of the permanent magnet, the first issue has been solved.

In order to solve the second and third problems, the outer conical surface is
A Mizuhisa H1 stone movable part resembling an abacus bead, two permanent magnet fixing parts sandwiching it from both sides and having an inner conical surface parallel to the outer conical surface, and a housing that holds them. It is composed of. The magnetic poles of the three magnets repel each other, and the movable part rotates without contact. In this way, the movable part that rotates and hangs while maintaining an appropriate gap between the fixed part and the fixed part by repulsive force is housed in the housing, so it can be used easily like a conventional bearing, and can be used as a second or third part. solved the problem.

[Operation] According to the above-described means of the present invention, since no electromagnet is used, an expensive control mechanism is unnecessary and power consumption is completely eliminated. In addition, since the 6R air bearing is constructed only by the repulsive force of the permanent magnet, the ♀ for the upper punch is stable, and a long-life bearing that is small and wear-free can be obtained. Since the magnetic bearing is completely constructed within the housing, radial
Completely compatible with bearings and easy to use.

[Example] The details of the lin air bearing of the present invention will be explained with reference to an example shown in the sectional view of FIG.

A rotating body 1 is rotatably supported around a rotating shaft 2. The shape of the movable part 61 stone 5 is the shape of the outer edge of an abacus ball cut out (the cross-sectional length of that part is indicated as L).The direction of magnetization is the axial direction, from N to S in the figure. is indicated by an arrow. What should be noted here is that when the inclination angle 5 is increased and L is decreased, the permeance coefficient becomes smaller due to the shape effect, and the flux density at the surface 6R of the magnet also decreases. Therefore, for example, as shown in the cross-sectional view shown in FIG.
If L is made smaller, the angle of inclination of the inner conical surface of the fixed part 4 will inevitably become larger, so the surface magnetic flux strength will be very small in parts a and a' in the figure, and in parts b and b'. becomes larger. Therefore, in the case of the combination shown in Figure 2, the strong and weak parts of the surface &n flux density are a, and they oppose each other as a' and b',
It was found that the repulsive force was extremely reduced and the effect of 61 ki 4 yuuke was virtually eliminated. Therefore, in order to obtain an effective repulsive force, it was necessary to make the inclination angle of the movable part 5R stone 5 as narrow as about IO degrees, and to make the permeance coefficient the same value in all parts. Of course, if the tilt angle is set to 0, the eccentricity control in the radial direction will no longer be effective, and the bearing will lose its effectiveness.
For small bearings, an angle between about 3 degrees and about 20 degrees has been suitable. Next, reference numeral 6 is a cylindrical ring for joining with the rotating shaft 2, which is matched with the inner diameter surface. Magnets 4 and 4' are fixed parts, which are parallel to their inner conical surfaces and maintain the air gap by repulsive force without contact.

The adjustment of this gap is fixed in the optimum position by the housings 7 and 7'. These 4 and 67 are 6R air bearings that replace radial bearings, and in order to maintain the rotation of the rotating body l, there is a
Requires exactly the same magnetic bearing.

[Effects of the Invention] As can be seen from the above embodiments, there is an effect that the rotating shaft can be maintained floating at a height of 6R above its support without consuming power. Furthermore, it is possible to obtain a bearing that is free from wear, has a long life, and is free from mechanical noise and noise. Furthermore, it has a simple structure and is easy to assemble, and at the same time, the movable shaft is already floating when it is assembled into one housing, so it has the same easy usage effect as a radial bearing.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the magnetic bearing of the present invention. FIG. 2 is a sectional view illustrating the shape a constraint. FIG. 3 is a sectional view showing an example of a conventional magnetic bearing.・Rotating body・Rotating shaft・Rotating shaft neck・Fixed part M stone・Movable part En stone・Cylindrical ring 7. 7' ・More than housing

Claims (1)

[Claims] The permanent magnet that serves as the movable part has a shape similar to an abacus ball, and its outer conical surfaces are sandwiched between two permanent magnets each having a parallel inner conical surface. The magnetization direction of the two magnets is axial, and the opposing surfaces of each magnet are
A magnetic bearing characterized in that an appropriate gap is maintained by a housing of a fixed part magnet so that the repulsion of the same magnetic poles works and the movable part magnet can rotate without contact.