JPH0155682B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bearing flywheel having a jimbering mechanism used for attitude control of an artificial satellite.

Conventionally, there has been a device of this type as shown in FIG. In this figure, 1 is a rotor, 2 is rotating magnetic poles arranged at the upper and lower parts of the rotor 1,
3a and 3b are upper radial magnetic bearing cores; 4
a and 4b are the excitation coils, 3c and 3d are the lower radial magnetic bearing cores, 4c and 4d are the excitation coils, 5a and 5b are the upper and lower radial position detection pick-ups, respectively, and 6a and 6b are the upper and lower parts. Iron core for thrust magnetic bearing, 7
a and 7b are their excitation coils, 8 is a thrust position detection pick-up, 9 is the rotor of the motor, 1
0 is the motor stator, 11 is the motor coil,
12 is a wheel casing.

FIG. 2 is a diagram showing the configuration of the upper radial magnetic bearing of this device, and 13 is a position detection electric circuit;
14 is a phase compensation circuit, and 15 is a power amplifier.

Next, the operation of the radial magnetic bearing will be explained using FIG. 2. When the rotating magnetic pole 2 is displaced in the x direction, the displacement is detected as an electrical signal by the radial position detection pickup 5a and the position detection electric circuit 13. After this electrical signal is compensated by the phase compensation circuit 14, the power amplifier 1
5 to decrease the excitation current of the excitation coil 4a and increase the excitation current of the excitation coil 4b. Therefore, the magnetic attraction force by the radial magnetic bearing core 3a decreases, and the magnetic attraction force by the radial magnetic bearing core 3b increases.
The rotating magnetic pole 2 is returned to its original position. As described above, the rotating magnetic pole 2 is supported without contact by detecting the displacement of the rotating magnetic pole 2 with the radial position detection pick-up 5a and controlling the magnetic attraction force of the radial magnetic bearing cores 3a and 3b accordingly. Ru. Furthermore, when a bias voltage is applied to the input terminal of the power amplifier 15 by superimposing it on the displacement signal from the radial position detection pickup 5a, the rotating magnetic pole 2 can be moved to any position in the x direction by changing the magnitude of the bias voltage. Can be stably moved to any position. The same applies to the y direction. The rotor 1 is also supported by the thrust magnetic bearing based on the same principle. That is, as shown in FIG. 1, the displacement of the rotating magnetic pole 2 in the z direction is detected by the thrust position detection pickup 8, and the excitation coil 7 is adjusted accordingly.
By controlling the currents of a and 7b, the rotor 1
is supported in the z direction without contact.

In this way, in the conventional satellite magnetic bearing flywheel, the rotor 1 is supported in a non-contact manner by one set of thrust magnetic bearings and two sets of radial magnetic bearings. The attitude angle of the satellite is controlled by changing the bias voltage of the power amplifier 15 in the up and down z-direction and the left and right x and y directions to change the inclination of the rotation axis of the rotor 1. For example, in FIG. 1, the axis of rotation of the rotor 1 can be moved from z to z' by increasing the bias voltage of the excitation coils 4a and 4b and decreasing that of the excitation coils 4b and 4c.

However, conventional magnetic bearing flywheels for satellites require 5 sets of control devices and 10 electromagnets to control rotor displacement in a total of 5 directions: the z-direction of the thrust, and the x and y directions of the upper and lower radials. Therefore, the wheel configuration is complicated and expensive, and reliability is significantly reduced.

This invention was made to eliminate the drawbacks of the conventional bearings as described above, and by giving the thrust magnetic bearing the function of a radial bearing,
The object of the present invention is to provide a magnetic bearing flywheel for an artificial satellite that has a simplified non-contact support mechanism for the rotor. This invention will be explained below.

FIG. 3 is a cross-sectional view showing one embodiment of this invention.
2a and 2b are inner and outer rotating magnetic poles respectively attached concentrically to the rotating shaft, and 16 is a radially magnetized ring-shaped permanent magnet.
The operating principle of the magnetic bearing shown in the lower part of FIG. 3 will be explained using FIG. 4.

FIG. 4 is an enlarged view of the lower magnetic bearing of FIG. 3. As shown by the solid arrow, the magnetic flux emitted from the N pole of the ring-shaped permanent magnet 16 attached to the rotating shaft passes through the rotating magnetic pole 2b, is divided vertically, passes through the air gap, and is sent to the upper and lower thrust magnetic bearings. It flows into the iron cores 6a and 6b, passes through the air gap again, reaches the rotating magnetic pole 2a, and returns to the S pole. At a position where the upper gap between the thrust magnetic bearing core 6a and each rotating magnetic pole 2a, 2b and the lower gap between the thrust magnetic bearing core 6b and the lower gap are equal, each thrust magnetic bearing core 6
The magnitude of the magnetic flux passing through a and 6b is also equal,
No suction force acts on the rotor 1. However, this position is unstable; for example, if the rotor 1 moves even slightly downward, the rotor 1 will move to the radial magnetic bearing core 6.
It is attracted to the b side. Therefore, a control circuit similar to that of the thrust magnetic bearing shown in FIG. 1 is configured to stabilize this position. That is, when the axial displacement of the rotor 1 is detected by the thrust position detection pick-up 8 and the magnetic flux from the excitation coils 7a and 7b is caused to flow as shown by the dotted line, the magnetic flux increases in the upper air gap and decreases in the lower air gap. Therefore, the rotor 1 is sucked upward and returned to its original position. When the thrust bearing of the satellite flywheel is configured in this way, the radial direction is passively restored by the attractive force of the permanent magnet 16.

As explained in detail above, the present invention has a structure in which an excitation coil is mounted at one end of the rotating shaft in the groove of the core for thrust magnetic bearings, so that the axial displacement of the rotor is controlled by magnetic attraction force, and the radial displacement is Since a thrust magnetic bearing is provided which restores the magnetic field without control by the axial magnetic attraction force of a permanent magnet, the excitation coil can be easily attached and leakage magnetic flux is extremely reduced. In addition, the attraction force of several electromagnets is controlled at the other end of the rotating shaft in response to electric signals of two radial displacements perpendicular to the rotating shaft, and this shaft end is moved anywhere within the plane orthogonal to the rotating shaft. Since a radial magnetic bearing is provided to support the device at the position of , the gimbaling effect is small, so it can be constructed with an electromagnet, which has the advantage of making the device inexpensive and highly reliable.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a conventional magnetic flywheel for an artificial satellite, Fig. 2 is a schematic diagram for explaining the structure and operation of the upper radial magnetic bearing of a conventional magnetic bearing flywheel for an artificial satellite, and Fig. 3 is a schematic diagram for explaining the structure and operation of the upper radial magnetic bearing of the conventional magnetic bearing flywheel for an artificial satellite. FIG. 4 is an enlarged view of the lower magnetic bearing shown in FIG. 3, which is a sectional view showing one embodiment of the present invention. In the figure, 1 is a rotor, 2, 2a, 2b are rotating magnetic poles, 3a, 3b are radial magnetic bearing cores, 4
a, 4b are excitation coils, 5a, 5b are pick-ups for detecting displacement in the radial direction, 6a, 6b are iron cores for thrust magnetic bearings, 7a, 7b are excitation coils, 8
1 is a thrust position detection pickup, 9 is a motor rotor, 10 is a motor stator, 11 is a motor coil, 12 is a casing, 13 is a position detection electric circuit, 14 is a phase compensation circuit, 15 is a power amplifier, and 16 is a It is a ring-shaped permanent magnet. In addition,
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In a magnetic bearing flywheel that controls the attitude angle of a satellite by controlling the inclination of the rotational axis of the rotor, an excitation coil is installed in a groove of a thrust magnetic bearing iron core at one end of the rotational axis. A thrust magnetic bearing is provided at the other end of the rotary shaft and is perpendicular to the rotary shaft. It is characterized by having a radial magnetic bearing that controls the attraction force of a plurality of electromagnets according to two electric signals of radial displacement to support the shaft end at any position within a plane perpendicular to the rotation axis. Magnetic bearing flywheel for satellites.