JPS6211218B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention enables non-contact support of the rotor section with respect to the stator section, as well as radial position control, through the interaction of the attraction force of the permanent magnets and the control attraction force of the electromagnetic coils. This invention relates to a multi-axis controlled magnetic bearing.

A magnetic bearing is a bearing that uses magnetic force to support a rotating object. These magnetic bearings have become popular in recent years due to their remarkable characteristics, such as no life limit due to friction or fatigue, extremely low friction torque, and excellent compatibility with special environments such as vacuum, high temperature, and low temperature. Research is being conducted on Examples of this use include centrifuges, vacuum pumps, gyroscopes, precision measuring instruments,
It is seen as promising for use in control equipment for artificial satellites.

In general, many magnetic bearings use permanent magnets, and the direction of magnetization is often radial. However, in reality, if a permanent magnet is magnetized in the axial direction, the magnet material is a flat yoke. However, in order to magnetize in the radial direction, the magnet material must be sandwiched between two cylindrical yokes with different radii, which is quite difficult to manufacture. In addition, magnetic circuits using radially magnetized permanent magnets require a yoke with a cylindrical portion of precise dimensions that closely contacts the magnetic flux entry and exit points of the permanent magnet, and a magnetic connection between the permanent magnet and the yoke. involves mechanical difficulties.

An object of the present invention is to use a permanent magnet magnetized in the axial direction and to provide a multi-axis controlled magnetic bearing with good performance. It consists of a rotor part and a stator part that rotate relative to each other in a non-contact manner, and the rotor part and the stator part each have first and second flat annular yokes on both sides and a third flat annular yoke between them. are arranged in parallel, and permanent magnets magnetized in the axial direction are sandwiched in two gaps between the first and third yokes and between the second and third yokes, and the magnetic poles of these permanent magnets are aligned with the rotor. The opposing portions of the first, second, and third yokes of the stator section are attracted to each other, and the magnetic flux from the permanent magnets is applied to the first, second, and third yokes on both sides.
The flow direction of the second yoke and the flow direction of the central third yoke are arranged so as to be opposite in the radial direction, and electromagnetic coils are provided in the first and second yokes of the stator part, and the rotor part and the stator part The magnetic flux of only the permanent magnet exists in the air gap magnetic path between the opposing third yokes, and the magnetic flux of both the permanent magnet and the electromagnetic coil coexists in the air gap magnetic path between the first and second yokes. In this way, the attractive force acting between the yokes of the rotor part and the stator part by the permanent magnet is adjusted by the controlled attractive force by the electromagnetic coil, and the radial position of the rotor part with respect to the stator part is controlled. It is characterized by the fact that it is designed to be carried out.

The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a longitudinal sectional view of the entire structure, and FIG. 2 is a plan view of the stator section 1 and rotor section 2. In this embodiment, a stator section 1 is integrally fixed to a shaft 3, and a rotor section 2 is configured to rotate around the stator section 1, and a flywheel 4 is attached to the rotor section 2. The stator section 1 consists of three flat annular yokes having the same inner and outer diameters, that is, first and second stator yokes 1 disposed on the outside.
1 and 12, and a third stator yoke 13 sandwiched between them, and between the first and third stator yokes 11 and 13 and between the third and second stator yokes 13 and 12. , annular permanent magnets 14 and 15 are sandwiched between them. These permanent magnets 14 and 15 are magnetized in the axial direction, and the polarity of the permanent magnets 14 and 15 is the same as that of the third stator yoke 1.
It is designed to be vertically symmetrical with 3 as the center. For example, as shown in FIG. 2, the first and second stator yokes 11 and 12 are radially magnetically divided into eight parts, and cross-shaped first and second electromagnetic yokes 16 and 17 are attached to them, respectively. ing. These electromagnetic yokes 16 and 17 are connected to the first and second stator yokes 1 on the X-axis and Y-axis in FIG.
Magnetically connected to the divided parts 1 and 12, X axis and Y axis
The divided parts that do not exist on the axis are electromagnetic yokes 16 and 17.
and the other divided portions are almost magnetically insulated. In addition, each leg portion 16 of the electromagnetic yokes 16 and 17
a, 16b, 16c, 16d and 17a, 17
A total of eight electromagnetic coils 18a, 18b, 18c, 18d and 19a, 1 are installed in each of the electromagnetic coils 18a, 17c, 17d (17b, 17d are not shown).
9b, 19c, and 19d (19b and 19d are not shown) are wound.

On the other hand, stator yokes 11 and 1 are provided in the rotor section 2.
Three flat annular yokes with a larger diameter than the stator yokes 11, 12, 13 are provided to rotate around the first and second stator yokes 21, 22 without contact. The inner peripheral surface is the first and second
The inner circumferential surface of the third rotor yoke 23 faces the outer circumferential surfaces of the stator yokes 11 and 12, respectively, and the inner circumferential surface of the third rotor yoke 23
The stator yoke 13 is disposed so as to face the outer circumferential surface of the stator yoke 13 . In addition, the rotor yoke 21, 2
Permanent magnets 24 and 25, which are magnetized in the axial direction similarly to the stator section 1, are arranged between the rotor yoke 23 and the stator 23 so that their polarities are symmetrical with respect to the third rotor yoke 23. Note that the polarity of the permanent magnets 24 and 25 of the rotor section 2 is the same as that of the permanent magnet 1 of the stator section 1.
The direction of polarity is opposite to that of 4 and 15.
26 is a position sensor for detecting displacement of the rotor portion 2 in the X-axis direction, and a position sensor for the Y-axis direction is omitted in the drawing. The output of the X-axis position sensor 26 passes through a control circuit and a power amplifier (not shown) to electromagnetic coils 18a, 18c, and 19a wound around the legs 16a, 16c, 17a, and 17c of the electromagnetic yokes 16 and 17 in the X-axis direction. ,1
A current is made to flow through 9c. Similarly, from the Y-axis position sensor (not shown), the electromagnetic coils 18b, 18d and 19b, 1 are wound around the legs 16b, 16d, 17b, 17d in the Y-axis direction.
A current is applied to 9d. Note that 27 is a ball bearing for supporting the rotor section 2 when the floating control of the rotor section 2 becomes impossible or when the rotor section 2 is stopped.

Since this embodiment has the above-described configuration, the first and second stator yokes 11 and 12 and the first and second rotor yokes 21 and 22 have permanent magnets 14 and 1.
Magnetic flux φ ₁ from 5, 24, 25 and electromagnetic coil 18
The magnetic flux φ ₂ generated from a, ..., 19a, ... coexists, and the air gap magnetic path G1, G2 between them is a so-called modulation gap, whereas the third stator yoke 13 and the third rotor - In the stator yoke 23, there is only a magnetic flux _φ1 due to only the permanent magnets 14, 15, 24, 25, and the air gap magnetic path G3 between the third stator yoke 13 and the third rotor yoke 23 is a non-modulating gap. It's summery. During operation, magnetic flux _φ1 passes from the N pole to the S pole of the permanent magnets 14, 15, 24, 25, that is, at the same time as magnetic flux _φ1 flows from the third rotor yoke 23 to the third stator yoke 13. , from the first stator yoke 11 to the first rotor yoke 21, and from the second stator yoke 1
The magnetic flux φ ₁ flows from the rotor yoke 2 to the second rotor yoke 22 . Therefore, due to the passage of this magnetic flux _φ1 , air gap magnetic paths G1, G2,
A magnetic attraction force will act on G3.

If we consider an ideal situation, this attractive force would be canceled out in all directions, and the rotor section 2 could be in an unstable state of equilibrium without being displaced in a certain radial direction, but in reality it is It is unavoidable that the rotor section 2 is displaced in one direction due to manufacturing precision and the like. For example, when the rotor section 2 moves a small amount in the positive direction of the X-axis, the left air gap magnetic paths G1, G2, and G3 between the stator section 1 and the rotor section 2 in FIG. , G3 becomes larger. Therefore, the left air gap magnetic paths G1, G2, G3
The magnetic flux φ from the permanent magnets 14, 15, 24, 25 in this part
₁ further increases, the attractive force increases during this time, and the magnetic flux φ ₁ of the right air gap magnetic paths G1, G2, G3 decreases, so that the rotor portion 2 is further drawn to the right side.

This displacement is detected by the X-axis position sensor 26, and the legs 1 of the electromagnetic yokes 16 and 17 in the X-axis direction are
A current is applied to the electromagnetic coils 18a, 18c and 19a, 19c provided in the electromagnetic coils 6a, 16c, 17a, 17c based on the control signal of the control circuit, and the attraction force of the magnetic flux φ ₁ by the permanent magnets 14, 15, 24, 25 changes. In other words, the air gap magnetic paths G1 and G2 on the right side pass from the stator yokes 11 and 12 to the rotor yokes 21 and 22, and the air gap magnetic paths G1 and G2 on the left side pass through the rotor yokes 21 and 22, and the air gap magnetic paths G1 and G2 on the left side pass through the rotor yokes 21 and 22. A magnetic flux φ ₂ is caused to flow in the direction shown by the dotted line from 21, 22 back to the stator yokes 11, 12. This magnetic flux φ ₂ cancels the change due to the displacement of the magnetic flux φ ₁ from the permanent magnets 14, 15, 24, 25, reduces the attractive force in the left air gap magnetic paths G1 and G2, and By increasing the suction force in paths G1 and G2, the overall suction force can be balanced and the rotor section 2 can be restored to its original neutral state. In this case, even if the rotor part 2 is displaced in the axial direction, the stator yoke 1 is caused by the flow of magnetic fluxes φ ₁ and φ ₂ .
1, 12, 13 and rotor yokes 21, 22, 23
will be restored so that their circumferential surfaces are directly facing each other. These operations are exactly the same in the Y-axis direction.

In this case, the first and second stator yokes 11,
12 is magnetically divided, so that the magnetic flux φ ₂ from the magnetic coils 18 and 19 passes only through the divided portions existing on the X-axis and Y-axis, and flows into the other divided portions. Therefore, it becomes possible to efficiently cause the magnetic flux φ ₂ to act for attraction.

The distance between the first and second stator yokes 11 and 12 and the rotor yokes 21 and 22 is increased, that is, the thickness of the stator section 1 and the rotor section 2 is increased to a certain extent,
Electromagnetic coils 18 arranged in the X-axis direction or Y-axis direction
By differentially supplying current to and 19, that is, by making the upper and lower control forces in opposite directions, minute jimbering control can be performed.

Note that the permanent magnet is not in the form of a single ring, but a plurality of permanent magnets having a simple shape, such as a cylindrical shape, may be arranged in a ring shape. Furthermore, although the yoke portion facing the air gap magnetic path has one tooth as shown in FIG. 1, it is also possible to use a plurality of teeth to improve the axial rigidity.

Further, the third stator yoke 13 and the third rotor yoke 23 are not necessarily one electromagnetic plate, but, for example, two yokes 13 as shown in FIG.
Even if a magnetically insulating inclusion 30 is provided between a, 13b and 23a, 23b, the effect is the same. In addition, as shown in FIG. 4, permanent magnets 1 are placed above and below the stator section 1 and rotor section 2 shown in FIG.
4', 15', 24', 25' and non-modulating yoke 1
If 3' and 23' are arranged in parallel in the axial direction, the rigidity in the axial direction will be improved.

Therefore, the multi-axis controlled magnetic bearing according to the present invention has the following effects.

(1) Since the permanent magnet is used while being magnetized in the axial direction, it is easy to manufacture the permanent magnet, and it is also easy to magnetically connect it to the yoke.

(2) Permanent magnets are placed in both the stator and rotor sections, resulting in high axial rigidity.

(3) The air gap magnetic path between the central stator yoke and the rotor yoke is a non-modulated gap made only of permanent magnets, so the magnetic flux density can be increased, and therefore the axial stiffness and the radial stiffness around the axis can be increased. Can be made larger.

(4) By differentially controlling the air gap magnetic path between the stator yoke and the rotor yoke on both sides, this single set of magnetic bearings can be used as a 4-axis control type magnetic bearing, and minute jimbering control is also possible.

[Brief explanation of the drawing]

The drawings show an embodiment of a multi-axis controlled magnetic bearing according to the present invention, in which FIG. 1 is a longitudinal sectional view thereof, FIG. 2 is a plan view of the stator section and rotor section, and FIGS. 3 and 4 are stator yoke. , is an explanatory diagram of a modification example of a combination of rotor yokes. 1 is the stator part, 2 is the rotor part, 3 is the shaft,
11, 12, 13 are stator yokes, 14, 1
5, 24, 25 are permanent magnets, 16, 17 are electromagnetic yokes, 18, 19 are electromagnetic coils, 21, 22, 2
3 is a rotor yoke, 26 is a position sensor, φ ₁ , φ
₂ is a magnetic flux, and G1, G2, and G3 are air gap magnetic paths.

Claims (1)

[Claims] 1. Consisting of a rotor part and a stator part, each of which rotates relatively around one axis without contact with the other,
The rotor part and the stator part are respectively connected to the first
A second flat annular yoke and a third flat annular yoke between them are arranged in parallel, and the second flat annular yoke and the third flat annular yoke are arranged in two spaces between the first and third yokes and between the second and third yokes. Permanent magnets magnetized in the axial direction are sandwiched, and the magnetic poles of these permanent magnets are attracted to each other by the opposing parts of the first, second, and third yokes of the rotor and stator parts, and are separated from the permanent magnets. The magnetic flux flows in the flow direction of the first and second yokes on both sides and the third
The first and second yokes of the stator section are arranged so as to be radially opposite to the flow direction of the yokes, and the electromagnetic coils are provided in the first and second yokes of the stator section. The magnetic flux of only the permanent magnet exists in the magnetic path, and the magnetic flux of both the permanent magnet and the electromagnetic coil coexists in the air gap magnetic path between the first and second yokes. The attraction force acting between the yokes of the stator section and the stator section is adjusted by the controlled attraction force of the electromagnetic coil, and the radial position of the rotor section with respect to the stator section is controlled. Axis-controlled magnetic bearing. 2. The multi-axis controlled magnetic bearing according to claim 1, wherein the first and second yokes of the stator section are magnetically divided into at least three parts radially.