JPS5943220A - Gimbal-controlled magnetic bearing - Google Patents

Abstract

PURPOSE:To facilitate adjustment in manufacture and control during operation by providing a plurality of electromagnetic coils for gimbal control. CONSTITUTION:When a floating rotor portion 1 is inclined downward on the right side thereof and upward on left side thereof, clockwise magnetic flux phi1 is increased from a permanent magnet 5 of the rotor portion 1 to the lower right stator yoke 8b, and hence an electric current is supplied to gimballing electromagnetic coils 11a, 11b to generate counter-clockwise magnetic flux phi3 to the upper and lower stator yokes 8a, 8b based upon an output of a position sensor, resulting in that attraction force in gap magnetic paths of the right upper and lower portions of the rotor portion 1 is increased to cause the rotor portion 1 to float upward on the right side thereof. While the left rotor portion 1 is inclined upward, if an electric current is supplied to electromagnetic coils 13a, 13b in such a manner that counter-clockwise magnetic flux phi4 flows between the stator yokes 8a, 8b, the left rotor portion 1 is displaced downward, so that the rotor portion 1 is restored to its normal position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention supports the rotor part with respect to the stator part in a non-contact manner and enables jimbering control through the interaction of the attractive force of the permanent magnet and the control attractive force of the electromagnetic coil. It relates to magnetic bearings.

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, gyros, precision measuring instruments,
It is seen as promising for use in control equipment for artificial satellites.

In already known magnetic bearings, in order to perform gimbering control, the electromagnetic coil for levitation control is divided and gimbaling control is performed together with levitation control. difficult to control.

Furthermore, when the electromagnetic coil is mounted on a satellite as a control device for an artificial satellite, if a failure occurs in the electromagnetic coil, there is a problem that both levitation control and gimbaling control are impossible.

An object of the present invention is to eliminate the above-mentioned drawbacks, provide a plurality of electromagnetic coils for gimbaling control in addition to the electromagnetic coil for levitation control, and use separate electromagnetic coils for levitation control and gimbaling control. The purpose of the present invention is to provide a magnetic bearing that can perform jimbering control independently, making adjustment during manufacture and control during use easy. The attractive force acting between the rotor and stator parts is adjusted by the controlled attractive force by the electromagnetic coil provided in the stator part by the permanent magnet provided in the rotor part or (and) the stator part. In a magnetic bearing configured to perform levitation control in a direction, at least three electromagnetic coils for gimbering control are provided at equal intervals in the circumferential direction of the stator portion, separately from the electromagnetic coils for levitation control. It is characterized by:

Next, the present invention will be explained in detail based on illustrated embodiments.

In FIG. 1, reference numeral 1 denotes a disk-shaped rotor section, and stator sections 2a are arranged symmetrically above and below the rotor section 1.
, 2b are arranged. In the rotor part 1, two short cylindrical first and second rotor yokes 3 are arranged concentrically,
A donut-shaped permanent magnet 5 magnetized in the radial direction is sandwiched between the magnets 4 and 4. Further, a flywheel 6 is provided on the outside of the first rotor yoke 3, and a flywheel 6 is provided on the outside of the first rotor yoke 3.
rotates around a central shaft 7 that connects the stator parts 2a and 2b. The stator parts 2a, 2b have donut-shaped stator yokes 8a, 8b with a U-shaped cross section, and these open ends 9a, 9b are first and second, respectively.
The end portions of the rotor yokes 3 and 4 are arranged opposite to each other. In addition, levitation electromagnetic coils 10a and 10b are wound around the central axis 7 on the inner sides of the stator yokes 8a and 8b, respectively, and as shown in FIG. Four electromagnetic coils for gimbaling 11a, 12a, 13a, 14a; 11b, 12 at equal intervals in the circumferential direction.
b, 13b, and 14b (12b and 14b are not shown). These gimbering electromagnetic coils 11
a, . . . are stator yoke 8 as shown in FIG.
A total of four notches 1 provided on the outer sides of a and 8b
5a and 15b (15b is not shown), and are vertically symmetrically provided at positions in the X-axis and Y-axis directions when at rest. Furthermore, these notches 15a and 15b have notches 16a and 16b (16b not shown) on the open ends 9a and 9b, respectively, and the number of turns of the gimbering electromagnetic coils 11a, . . . is small. In some cases, the depth of the notches 15a and 15b may be small.

Since this embodiment has the above-described configuration, during operation, the magnetic flux φ1 is transmitted from the N pole of the permanent magnet 5 to the first rotor yoke 3.
It flows into the stator yokes 8a, 8b via the stator yokes 8a, 8b, goes around the cross section of the stator yokes 8a, 8b, and returns from the second rotor yoke 4 to the south pole. Now, if we consider an ideal state in which the rotor section 1 has no weight, etc., the attractive force acting between the rotor yokes 3, 4 and the stator yokes 8a, 8b due to the magnetic flux φ1 of the permanent magnet 5 is canceled out at the top and bottom. The rotor section 1 will float in the air.

In reality, it is unavoidable that the rotor section 1 deviates due to its own weight and manufacturing precision. For example, the rotor section 1
moves a minute amount downward in parallel to the central axis 7 due to its own weight, the gap between the open end 9b of the lower stator section 2b and the rotor yokes 3 and 4 is small, and the gap between the open end 9a of the upper stator section 2a and the rotor yoke is small. The gap between 3 and 4 becomes larger. As a result, the magnetic resistance of the lower air gap magnetic path is small and the upper magnetic resistance is large, and the magnetic flux φ1 from the permanent magnet 5 largely flows to the lower stator yoke 8b, so that the magnetic resistance between the lower stator yoke 8b and the lower stator yoke 8b increases. The suction force increases and the rotor section 1 is increasingly drawn downward. Rotor part 1
This axial deviation is detected by position sensors installed symmetrically around the central axis 7 in the X-axis and Y-axis directions, two each in the vicinity of the flywheel 6 of the levitation electromagnetic coils 10a and 10.
b, in a direction that cancels out the lower magnetic flux φ1 of the magnetic flux φ1 from the permanent magnet 5, that is, in the example, counterclockwise within the cross section of the right side of the stator yokes 8a and 8b, Electromagnetic coil 1 in the clockwise direction within the cross section
By passing the magnetic flux φ2 generated from 0a and 10b, the axial deviation of the rotor portion 1 can be restored to its original state, and the rotor portion 1 can be stably floated at the same position at all times.

However, when the rotor section 1 is tilted, for example, when the right side of the rotor section 1 is tilted downward and the left side is tilted upward as shown in FIG.
Restoration is impossible with 0b alone. In this case, from the permanent magnet 5 of the rotor part 1, the stator yoke 8b on the lower right side
Since the clockwise magnetic flux φ1 increases, the gimbaling electromagnetic coils 11a, 11 are adjusted based on the output of the position sensor.
If current is applied to the electromagnetic coils 11a and 11b for jimping so that a counterclockwise magnetic flux φ3 is generated in the upper and lower stator yokes 8a and 8b from b, the attractive force in the air gap magnetic path at the upper and lower right side of the rotor section 1 The force increases, and the right side of the rotor section floats upward. In addition, since the rotor section 1 on the left side is tilted upward at this time, the magnetic flux φ from the clockwise permanent magnet 5 is generated between it and the stator yoke 8a on the upper left side.
1 flows, but on the other hand, the upper and lower stator yokes 8a, 8 flow from the gimbaling electromagnetic coils 13a, 13b.
If current is applied to the electromagnetic coils 13a and 13b so that a counterclockwise magnetic flux Φ1 flows between b, the left rotor part 1 will be displaced downward, and the rotor part 1 can be restored to its normal position. . Note that the magnetic bearing with the shape shown in Figure 1 is generally unstable with respect to the tilt angle unless gimbaling control is performed, so if you want to use it as a single-axis control type even if the gimbaling control system is broken, , passive centripetal magnetic bearings must be installed above and below to stabilize the system.

The above explanation has been about the gimbaling control in the X-axis direction, but in the Y-axis direction, the gimbaling electromagnetic coil 1
2a, 14a, 12b, and 14b may be used in the same manner. Furthermore, this gimbaling control can also be used to intentionally tilt the rotor section 1 in order to control the attitude of the artificial satellite. These levitation electromagnetic coils 10a
, 10b, jimbering electromagnetic coil 11a,...
The control using the electromagnetic coil is performed by supplying current to the electromagnetic coil according to a signal from a control circuit (not shown) based on the outputs of at least two position sensors arranged in each of the X-axis and Y-axis directions. become. Note that for axial direction control, the sum of the four sensor outputs described above is used, but for gimbaling control, for example, if the difference between the two sensor outputs on the X-axis is used, the slope around the Y-axis can be calculated. You can use this signal as it is proportional to the angle, or if you just want to make the tilt angle zero, you can set the current to the upper and lower pair of gimbering electromagnetic coils so that the sensor output in the vicinity becomes zero. A servo system may be configured and provided.

In this gimbaling control, it is preferable that a pair of upper and lower gimbaling electromagnetic coils act as a pair. For example, the magnetic flux generated from one gimbaling electromagnetic coil flows into the magnetic path of the adjacent electromagnetic coil. Doing so would result in inefficient control. Therefore, as shown in FIG. 3, the rotor yoke 3 of the stator yokes 8a and 8b
, 4 are partially provided with notches 16a, 16b in the open ends 9a, 9b to prevent the generated magnetic flux from proceeding to the yoke portion around which the electromagnetic coil of the adjacent set is wound. is suitable. In this case, the effect is even greater if the stator yokes 8a and 8b are magnetically divided into four equal parts radially. In addition, it is preferable that the upper and lower pairs of gimbering electromagnetic coils act simultaneously in opposite directions on the left and right sides, and in this case, the magnetic fluxes φ3 and φ4 in FIG.
The stator yokes 8a and 8b are connected to form a large loop.

In the embodiment, the donut-shaped permanent magnet 5 is disposed in the rotor section 1, but this is not necessarily an integrated permanent magnet 5, but a divided permanent magnet coil between the first and second rotor yokes 3 and 4. There is no problem even if it is set to . In addition, four electromagnetic coils for gimbering were provided in the circumferential direction of the stator yokes 8a and 8b, but three were arranged at equal intervals and the force generated by the electromagnetic coils was used to It is also possible to control the gimbaling of However, in the case of four electromagnetic coils 11a arranged symmetrically in the X-axis and Y-axis directions with the central axis 7 as the center, it is easier to operate the electromagnetic coils 11a so that forces in opposite directions act on each other. This allows for better controllability. Further, in the embodiment, the gimbering electromagnetic coils 11a, . . . are arranged on the outer side of the stator yokes 8a, 8b, but there is no problem if they are arranged on the inner side.

Furthermore, as shown in FIG. 4, the stator section 2 may be one and the rotor sections 1a, 1b may be provided above and below, or in that case, the rotor sections 1a, 1b may be simply rotor yokes 3a, 3b. It is also possible to arrange the permanent magnets 5 in the stator section 2. In this second embodiment,
The number of permanent magnets 5 is two, and the stator yoke 8 of the stator section 2
The levitation electromagnetic coils 1Oa and 1Ob, which are inserted between the stator yoke 8' and 8'' and wound around the central axis 7, are provided symmetrically above and below the stator yoke 8'. , 14 (12 and 14 are not shown) are also 4
They are arranged at equal intervals on the divided stator yoke 8+. The operation of this embodiment is basically the same as that of the previous embodiment shown in FIG. 1, so a description thereof will be omitted.

As explained above, the magnetic bearing capable of gimbaling control according to the present invention is provided with a plurality of electromagnetic coils for gimbaling control in addition to the electromagnetic coil for levitation control, so these controls can be performed separately and independently. The adjustment or controllability is much better than that of conventional magnetic bearings. Furthermore, even if the electromagnetic coil for gimbaling control fails, the levitation control electromagnetic coil can control the levitation, so there is an advantage that a fatal failure will not occur even when mounted on an artificial satellite.

[Brief explanation of the drawing]

The drawings show an embodiment of a magnetic bearing capable of gimbaling control according to the present invention, and FIG. 1 is a longitudinal cross-sectional view of the first embodiment, FIG. 2 is a plan view of the stator section, and FIG. 3 is a longitudinal sectional view of the first embodiment. 4 is a perspective view of the stator yoke, and FIG. 4 is a longitudinal sectional view of the second embodiment. 1, 1a, 1b are rotor parts, 2, 2a, 2b are stator parts, 3, 3a, 3b, 4 are rotor yokes, 5 is permanent magnets, 8a, 8b, 8', 8'' are stator yokes, 10
a, 10b are electromagnetic coils for levitation, 11, 11a, 11b
, . . . 14, 14a, 14b are electromagnetic coils for gimbaling, and 15 is a notch. Patent applicant Director of Aerospace Technology Research Institute

Claims (1)

[Claims] 1. Consisting of a rotor part and a stator part that can rotate relative to each other without contact, and a permanent magnet provided in the rotor part or (and) the stator part acts between the rotor part and the stator part. In a magnetic bearing that performs axial levitation control by adjusting the attraction force by controlling attraction force using an electromagnetic coil provided in the stator part, at least three gimbering controls are provided at equal intervals in the circumferential direction of the stator part. electromagnetic coil for
A magnetic bearing capable of gimbaling control, characterized in that it is provided separately from the electromagnetic coil for levitation control. 2. The electromagnetic coil for gimbaling control is capable of gimbaling control according to claim 1, wherein the electromagnetic coil for gimbaling control is wound between notches provided at equal intervals in the circumferential direction of the stator yoke. magnetic bearing.