JPS5884221A - Five-axle control type magnetic bearing - Google Patents

Abstract

PURPOSE:To simlify the construction of a five-axle control type magnetic bearing for a gyroscope and the like by disposing two permanent magnets, forming symmetrically a magnet flux in each void magnetic path between the yokes of a rotor and a stator and cancelling the magnet flux change following displacement by means of an electromagnetic coil. CONSTITUTION:The magnetic fluxes phi1, phi2 of a first and second permanent magnets 7, 8 flow symmetrically to each other as an arrow shows. When a rotor portion 1 is moved downwardly from the neutral position, the clearance of a void magnetic path 17 becomes narrow and the magnetic fluxes phi1, phi2 therein are increased. Accordingly, said rotor portion 1 is further moved downwardly and a first position detector 41 is operated. Thus, an electric current is supplied to said electromagnetic coil 20 and the magnetic flux phi3 flows in a void magnetic path 16 and said rotor 1 is returned. Also, the X-axial displacement of said rotor 1 operates a void magnetic path 23 a position detector 42 and electromagnetic coils 34, 36 or a void magnetic path 24, a position detector 44 and electromagnetic coils 34, 36. With regard to Y-axis, the similar operation is carried out. As a result, the magnetic field change type with a simple construction can be constituted.

Description

Detailed Description of the Invention The present invention supports the rotor part in a non-contact manner with respect to the stator part through the interaction of the attractive force of the permanent magnets and the controlled attractive force of the electromagnetic coil, and in particular supports the rotor part in all directions. This book is about a single-axis control type magnetic bearing that enables minute surface posture control.

A magnetic bearing is a bearing that uses magnetic force to support a rotating object. This magnetic bearing is designed for friction and
It has been actively researched in recent years due to its remarkable features such as no life limit due to fatigue, extremely low friction torque, and excellent suitability for special environments such as vacuum, high temperature, and low temperature. This is so-called -axis or two-axis control to control the posture of the bearing, and the remaining degrees of freedom are passively stable, so vibration and wobbling are likely to occur, and the rigidity of the bearing is low. In addition, so-called ball-axis control type magnetic bearings that control five directions: the direction of the rotational axis, two axes perpendicular to it, and two directions of inclination around the two axes are also known, but electromagnets that do not use permanent magnets Since it is controlled, it has the disadvantage of large power loss. Furthermore, conventional magnetic bearings often use a permanent magnet for each control axis4.
．． The disadvantage is that the structure is extremely complicated.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a magnetic field modulation type ball axis control magnetic bearing that performs so-called five-axis control using two permanent magnets and is easy to control. In particular, it consists of a rotor part and a stator part that can rotate relative to each other without contact, and the rotor part, the stator part, or both are magnetized in the axial direction. A second permanent magnet is provided between the yokes K of the rotor section and the stator section, and first and second gaps through which the magnetic fluxes of the first and second permanent magnets are branched and pass through in mutually opposite directions in the axial direction. A magnetic path is formed so that the magnetic flux generated by the first electromagnetic coil provided in the stator section passes through the first and second air gap magnetic paths in series, and both axial ends of the rotor section and the stator section (The stator yoke is circumferentially surrounded by rotor yokes, and the magnetic fluxes of the first and second permanent magnets pass in the radial direction between them.
, a fourth air gap magnetic path is formed, and the stator yokes at both axial ends of the stator section are roughly divided radially into at least three parts, each of which is wound with at least two sets of electromagnetic coils. The magnetic flux generated by the rotor is caused to pass through the third and fourth air gap magnetic paths, respectively, and the position is detected in a total of five directions: the axial direction and two symmetrical directions perpendicular to the axial direction at both ends of the rotor part in the axial direction. In order to achieve this, at least five position detectors are arranged around the rotor section, and the current supplied to the corresponding electromagnetic coil is controlled based on the output of each position detector.

The present invention will be explained in detail based on illustrated embodiments. Pottery,
For convenience of explanation, both ends in the axial direction and two directions orthogonal to these two axes will be described as the Y-axis and the Y-axis.

FIG. 1 is a longitudinal sectional view of the magnetic bearing according to the present invention, and FIG.
The figure is a sectional view taken along the line π-■ in FIG. 1. This magnetic bearing consists of a rotor part 1 and a stator part 2, and is adapted to rotate around a rotor part 1d and a stator part 2 around a rotation axis 3 of the stator part 2. An annular first rotor yoke 4 made of a magnetic material is provided at the vertically symmetrical center of the rotor portion 1, and the circumference thereof has a short cylindrical shape having upper and lower end portions 5.6. Above and below the peripheral edge of the first rotor yoke 4, there are first cylindrical magnets magnetized in the axial direction.
A second permanent magnet 1.8 is connected, and second and third rotor yokes 9.1o made of an annular magnetic material are arranged at the upper and lower ends of each rotor yoke. The polarity of the first and second permanent magnets 7.8 is such that the ends in contact with the first rotor yoke 4 have the same polarity as the south pole S, and the ends in contact with the second and third rotor yokes 9.10 have the same polarity. It is called North Pole N. On the other hand, the stator portion 2 is provided with a first stator yoke 15 centered around the rotating shaft 3, and a first stator yoke 15, a first stator yoke 15, a first stator yoke 15, a second stator yoke 15, etc. An opening is provided with ends 18, 19 forming an air gap magnetic path 16,17. Moreover, this first stator yoke 15, first and second air gap magnetic paths 16, 17 . A first electromagnetic filter 20 is wound around the first stator yoke 16 to allow magnetic flux to pass through the magnetic circuit made up of the first rotor yoke 4 . Second and third stator yokes 21.22 are provided at the upper and lower ends of the first stator yoke 16, and are magnetically connected to the stator yoke 15. 2nd, 3rd
An annular third yoke 9 and the inner periphery of the yoke 9 and
, a fourth air gap magnetic path 23,24 is formed. Second,
As shown in FIG. 2, the third stator yokes 21 and 22 have four notches 25 and 26.2 toward the center thereof.
7°28 are provided at equal intervals, and the stator yoke 2
1 and 22 are divided into four parts. However, the third
(The stator yoke notches and split parts are not shown). Also, these divisions 29.30.

31.32 each have four electromagnetic coils 33.34.
35% 36 are wound. These electromagnetic coils are opposite electromagnetic coils, namely 33.35 and 34,36.
are connected in series or in parallel, and in the second stator yoke 21, there are two types of electromagnetic circuits using electromagnetic coils, and a total of four types of current are applied to these electromagnetic coils. It is now possible to flow independently.

In the same example, Section 2. Third rotor yoke9.
10, and the second and third stator yokes 21 and 22,
For example, eddy current loss during high-speed rotation is reduced by using a laminated plate made of electromagnetic steel plates or the like. or,
This magnetic bearing has five position detectors, namely a first position detector 41 for detecting the axial position of the rotor section 1;
Second and third position detectors 42 and 43 for detecting the position of the upper part of the rotor part 1 in the X-axis and Y-axis directions, respectively, and the position of the lower part of the rotor part 2 in the X-axis and Y-axis directions, respectively. 4th thing to do. Sixth position detectors 44, 45 (however, 45
(not shown) are arranged around the rotor portion 1. These position detectors (5 pieces) are each connected to a control circuit (not shown), and a control signal from this control circuit flows to each electromagnetic coil'. That is, the first electromagnetic coil 2o is supplied with power based on the output of the first position detector 41, and the second stator yoke 2102 types of coils are supplied with second and third position detectors 42 and 43, respectively. Correspondingly, fourth and fifth position detectors 44 and 45 are configured to supply control currents to the electromagnetic coils of the third stator yoke 22, respectively. Also, 46
, 46 are emergency bearings with which the casing 47 or 48 of the rotor section 1 can come into contact when stopped or in an emergency.

Since the embodiment of the present invention has the above-described configuration, the magnetic flux φ generated by the first permanent magnet 7 is emitted from the north pole N, and the magnetic flux φ, generated by the first permanent magnet 7
The first air gap magnetic path 16 and the second air gap are connected from the opening ends 18 and 19 of the first stator yoke 15 via the rotor yoke 9, the third air gap magnetic path 23, and the second stator yoke 21. It passes through the magnetic path 17, reaches the first rotor yoke 4, and returns to the south pole S of the first permanent magnet 7. -Furthermore, the magnetic flux φ2 generated based on the second permanent magnet 8 flows vertically symmetrically with the path of the aforementioned magnetic flux φ, and the magnetic flux flowing inside the electromagnetic coil 20 cancels out and does not flow. In addition, permanent magnet 7.
Of course, if the polarity of 8 is reversed, the magnetic fluxes φ1 and φ2 will flow in the reverse order. Now here, the first electromagnetic coil 20
Considering the case where no current is supplied to the first,
Magnetic fluxes φ and φ2 act on the air gap magnetic paths 16 and 17 of wpI2 to attract each other in the axial direction. And the attractive force acting on the first and second air gap magnetic paths 16 and 17 is as follows.

The positions are approximately canceled out, and a neutral position exists between the rotor section 1 and the stator section 20. However, in reality, the rotor part 1
It is extremely difficult to maintain this neutral position as it is due to its own weight, etc. For example, the rotor section 1 moves downward, the first air gap magnetic path 16 opens, and the second air gap magnetic path 17 opens.
becomes narrower. Then, in the first air-gap magnetic path 16, the magnetic resistance increases, and the magnetic fluxes φ and φ2 decrease, and conversely, in the second air-gap magnetic path 17, the magnetic fluxes φ1 and φ increase, causing the rotor section 1 to move downward. The trend towards migration will become even greater. Therefore, a current is supplied to the first electromagnetic coil 2o, which detects the axial displacement of the rotor part 1 by the first position detector 41 that detects the axial position and outputs it to the axial control circuit. In the above case, from the first air gap magnetic path 16 to the second air gap magnetic path 17
A magnetic flux is generated in the direction shown by the dotted line. By doing this, the attractive force of the first air gap magnetic path 16 is strengthened and the attractive force of the second air gap magnetic path 17 is weakened, so the interval between the first air gap magnetic path 16 is narrowed and the second air gap magnetic path 16 is narrowed. The rotor section 1 moves in the axial direction so as to widen the gap between the air gap magnetic paths 17. In this way, while the axial position of the rotor section 1 is detected by the first position detector 41, the current supplied to the first electromagnetic coil 20 is adjusted by the axial direction control circuit. It becomes stable in a non-contact state with respect to the stator portion 2 at a predetermined position in the axial direction.

Moreover, the third air gap magnetic path 23 of the rotor part 1 and the stator part 2
In this case, the magnetic flux φ caused by the first permanent magnet 7 described above flows from the outer second rotor yoke 9 to the inner second stator yoke 21. Now, in Fig. 2, rotor section 1
If is displaced to the left side of the X-axis, the right side of the third air gap magnetic path 23 becomes narrower, and the left side becomes wider, and the magnetic flux φ is concentrated in the narrowed air gap magnetic path and is attracted. The force increases 9 and promotes the displacement of the rotor portion 1 so that it becomes increasingly narrow. Therefore, the displacement is detected by the second position detector 42, and the electromagnetic coils 34 and 34 located in the X-axis direction are
As shown by the dotted line, the magnetic flux φ4 passes through the second stator yoke 21 from the left side to the right side, flows to the second rotor yoke 9, goes around the rotor yoke 9, and returns to the left side again. By generating K, the rotor section 1 can be returned to its original neutral position by weakening the suction force in the narrowed part and increasing the suction force in the widened part. The same applies when the first rotor yoke is displaced in the Y-axis direction, and furthermore, the third rotor yoke 10
Even when is displaced in the X-axis or Y-axis direction, the fourth or fifth position detector 44, 45 can be used in the same manner.

These controls not only simply return the rotor section 1 to the neutral position, but also allow the rotor section 1 to be intentionally biased to one side. Therefore, the rotor section 1 can be tilted relative to the stator section 2 by controlling the upper and lower positions of the rotor section 1 independently, and by shifting the second or third rotor yoke 9.10. Therefore, the magnetic bearing according to the present invention can realize uniaxial control in the axial direction, two horizontal directions, and two directions of inclination, and these controls are extremely advantageous for attitude control of artificial satellites and the like.

In the embodiment, a permanent magnet that generates magnetic flux φ1 is interposed in the rotor portion IK, but it is not necessarily the case that the permanent magnet that generates the magnetic flux φ1 is located in the rotor portion IK.
There is no problem even if it is arranged in the stator section 2 instead of the rotor section 1, and it is also possible to provide it in both the rotor section 1 and the stator section 2. Furthermore, although the second and eighth stator yokes 21 and 22 are divided into four parts in the radial direction, they can be controlled by dividing them into three or more parts, and the electromagnetic coil is wound around all of these divided parts. Theoretically, control can be achieved by winding two or more K.

As explained above, the magnetic bearing according to the present invention enables single-axis control using five position detectors, and has the following advantages.

(1) Since it is a ball shaft control type, vibration and runout are small, and the bearing rigidity is greater than a bearing with a passive stable shaft that does not have control.

Q) Since it is a magnetic field modulation type, control is easy and power consumption is low.

O). Since the permanent magnet used is an axially magnetized type, it is easy to manufacture the permanent magnet.

(4) Since two permanent magnets are commonly used for uniaxial control, the number of permanent magnets used is small and the structure is simple.

(5) Slight swing control in all directions is possible.

[Brief explanation of drawings]

The drawings show an embodiment of the magnetic bearing according to the present invention, and FIG. 1 is a longitudinal cross-sectional view thereof, and FIG.
This is a nine-section map along the -■ line. 1 is the rotor part, 2 is the stator part, 4.9.10 is the rotor yoke, 7.8 is the permanent magnet, 16.17.23.2
4 is the air gap magnetic path, 16.21.22 is the stator yoke, 2
0.33.34.35.36 is an electromagnetic coil, 41,
42, 43, and 44 are position detectors. Patent applicant: Aerospace Technology Research Institute Director 1st W! J 2 2nd WJ

Claims (1)

[Claims] 1. Consisting of a rotor part and a stator part that can rotate relative to each other in a non-contact manner, two permanent magnets equivalent to two cylindrical shapes are magnetized in the axial direction of the rotor part, the stator part, or both. and forming first and second air gap magnetic paths between the yokes of the rotor part and the stator part, in which the magnetic fluxes of the first and second permanent magnets branch and pass in mutually opposite directions in the axial direction. , the magnetic flux generated by the first electromagnetic coil installed in the stator section passes through the first and second air gap magnetic paths in series, and a stator yoke is provided at both axial ends of the rotor section and the stator section. are circumferentially surrounded by a rotor yoke, forming third and fourth air gap magnetic paths through which the magnetic fluxes of the first and second permanent magnets pass in the radial direction, respectively, and the stator portion The stator yoke at both ends of the same axial direction is roughly divided radially into at least eight parts, each of which is wound with at least two sets of electromagnetic coils, and the magnetic flux generated by these electromagnetic coils is distributed to the third and forty-ninth air gap magnets, respectively. A total of six directions are provided in two symmetrical directions perpendicular to the axial direction and at both axial ends of the rotor part.
At least five position detectors are arranged around the rotor to detect the position in the direction, and the current supplied to the corresponding electromagnetic coil is controlled based on the output of each position detector.
A single-axis control type magnetic bearing characterized by: