JPH0427404B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bearing device used in ultra-high-speed rotating machines and the like, and more particularly, to a magnetic bearing device that eliminates the electric motor conventionally provided for rotating a rotating body.

Figure 1 is a configuration diagram of a general rotating machine using magnetic bearings. In the figure, 1 is a rotating body, 2, 3,
4 and 5 are the yokes of the axial magnetic bearings,
Rotator, excitation coil, position detector, 6, 7, 8,
9 is the yoke of the upper radial magnetic bearing,
Rotor, excitation coil, position detector, 11, 12,
13 are the yoke, rotor, and excitation coil of the electric motor, and 14, 15, 16, and 17 are the yoke, rotor, and excitation coil of the lower radial magnetic bearing, respectively.
The position detector 18 is a housing case.

In FIG. 1, a yoke 2 of an axial magnetic bearing is attached to the upper part of a housing case 18, and an excitation coil 4 is inserted into a slot provided downward. A rotating body 1 with a rotor 3 attached to the upper part is installed on the lower surface of the yoke.

The rotor 3 is suspended by the attractive force of the excitation coil 4, and the yoke 2 faces each other with a slight gap to form an axial magnetic bearing. Further, at the lower end of the rotary body 1, the rotary body 1
A position detector 5 is provided to detect the vertical position of. An upper radial magnetic bearing is installed above the rotating body 1, a lower radial magnetic bearing is installed below, and an electric motor is placed between them.

The upper magnetic receiver includes a rotor 7 attached to the rotating body 1, a yoke 6 surrounding the rotor 7 and attached to the housing case 18 with a slight gap, and a winding around the teeth of the yoke 6. It consists of a plurality of excitation coils 8 arranged in a line and a position detector 9 disposed above the yoke 6, and the rotor 7 is regulated in position in the radial direction by the attractive force of the excitation coil 8. The position detector 9 is used for position detection in the radial direction.

The lower magnetic bearing has the same structure as the upper magnetic bearing except that it is disposed at the lower part, so a description thereof will be omitted.

The electric motor includes a rotor 12 disposed approximately at the center of the rotating body 1 and attached to the rotating body 1;
A yoke 11 surrounds the rotor 12 and is attached to the housing case 18 with a slight gap.
and a plurality of excitation coils 13 wound around the teeth of the yoke 11, and operates as a normal electric motor.

As is clear from this example, magnetic bearings that support a rotating body using magnetic force have many parts such as position detectors and electromagnets, and the axial length of the rotating body is usually longer than mechanical bearings. It is. An increase in the number of parts leads to an increase in costs, and an increase in the axial length of the rotating body leads to an increase in the size of the equipment.
Also, the resonance point of the shaft is lowered, making it difficult to rotate at ultra high speeds.

The present invention eliminates these drawbacks, and by omitting the electric motor, reduces the number of parts and reduces the cost of magnetic bearings.Also, the axial length of the rotating body is made equal to that of mechanical bearings, which reduces the size of equipment. This allows ultra-high speed rotation by raising the resonance point of the shaft.

FIG. 2 is a configuration diagram of an embodiment of the present invention. In the figure, 1 is a rotating body, 2, 3, 4, and 5 are an axial magnetic bearing yoke, a rotor, an excitation coil, a position detector, and 21 , 22 are the upper radial magnetic bearing/motor yoke, the same rotor, 2
3 and 24 are an excitation coil and a position detector for the upper radial magnetic bearing, respectively; 25 is an excitation coil for the upper motor; 26 and 27 are a yoke and a rotor for the lower radial magnetic bearing and motor, respectively; 28,
29 is an excitation coil and position detector for the lower radial magnetic bearing, and 30 is an excitation coil for the lower motor. Note that the same parts as those in FIG. 1 are given the same reference numerals, so their explanation will be omitted.

As is clear from FIG. 2, an upper mechanism that serves as an upper radial magnetic bearing and an electric motor is provided above the rotating body 1, and a lower mechanism that serves as a lower radial magnetic bearing and an electric motor is provided below. It is provided.

The upper mechanism includes a rotor 22 attached to the rotating body 1, an upper radial magnetic bearing/motor yoke 21 surrounding the rotor 22 and attached to the housing case 18 with a slight gap,
Excitation coils 23 and 25 for the upper radial magnetic bearing and the electric motor are wound around the teeth of the yoke 21 (see FIG. 3), and above these, a position detector for the upper radial magnetic bearing is arranged. ing.

3 is a cross-sectional view of the electromagnet part extracted from the upper mechanism shown in FIG. 2. Specifically, the upper radial magnetic bearing/motor yoke 21 shown in FIG. The excitation coil of the electric motor is shown wound.

In the figure, 1a to 12a are tooth parts provided on the yoke, 1b to 12b are slot parts of the yoke, 1c to 12c are excitation coils of the upper motor, and 1d to 12d are excitation coils of the upper radial magnetic bearing. be.

Note that the lower mechanism has the same configuration as the upper mechanism, so a description thereof will be omitted.

From now on, the upper electric motor and upper radial magnetic bearing will be
They will be simply referred to as electric motors and radial magnetic bearings, and will be explained without distinguishing between upper and lower parts.

The electric motor used in ultra-high-speed rotating machines is generally a squirrel-cage, high-frequency, three-phase induction motor. In order to increase the number of rotations, the minimum number of poles is 2, and the total number of slots in the yoke is usually an integral multiple of 3 times the number of poles. The electromagnets of the radial magnetic bearing are x+, x
It must be possible to generate suction force in four directions: -, y+, and y-, and the direction in which each suction force is generated is 90°.
The number of teeth on the yoke must be such that the teeth can be shifted by a certain amount. In order for one yoke to function as both a radial electromagnet and a two-pole three-phase induction motor, these two conditions must be met. Therefore, as shown in Figure 3, 1d, 2
d, 3d to the excitation coil in the y+ direction, 4d, 5
d, 6d to x+ direction excitation coil, 7d, 8
d, 9d to the excitation coil in the y-direction, 10d, 1
If 1d and 12d are excitation coils in the x-direction,
From teeth 1a, 2a, 3a, in the y+ direction, 4a,
From teeth 5a and 6a, teeth 7a and 8 in the x+ direction
10a, 11 in the y-direction from teeth a, 9a
Teeth a and 12a generate radial electromagnets that generate attractive forces in four directions in the x-direction and are shifted by 90 degrees, and 1c, 7c, 4c, and 10c are
phase, 2c, 8c, 5c, 11c as v phase, 3c, 9
If c, 6c, and 12c are provided with W-phase three-phase windings, a three-phase induction motor with two poles and two slots for each pole and each phase can be constructed with a single-layer winding three-phase induction motor having a total number of slots of 12. Hereinafter, a device configured in this manner will be referred to as a dual-purpose electromagnet. By arranging two pairs of dual-purpose electromagnets, upper and lower, as shown in FIG. 2, a magnetically supported ultra-high-speed rotating machine can be realized without the need for an electric motor. There is a concern that the rotational torque of this dual-purpose electromagnet will be reduced compared to when the motor and radial magnetic bearing are separated as shown in Figure 1, but by arranging two sets of dual-purpose electromagnets, upper and lower, as shown in Figure 2. , rotational torque greater than that in the separated case shown in FIG. 1 can be obtained. Also, it is common for high-frequency induction motors to have silicon steel plates applied to the outside of the squirrel-cage rotor terminal bar. Therefore, if this is used as the rotor of the dual-purpose electromagnet of the present invention, rotational torque and attractive force can be obtained at the same time.

As is clear from the above explanation, the present invention allows a magnetic bearing device to be configured without an electric motor compared to the conventional system, resulting in a significant cost reduction, and the axial length of the rotating body can be reduced by using mechanical bearings. This is almost equivalent to the case where the shaft is rotated, and the device is made smaller and the resonance point of the shaft is raised, making it possible to rotate at ultra-high speed.
Although this embodiment describes a magnetic bearing that controls five axes, it goes without saying that it can also be applied to other magnetic bearings that control degrees of freedom in two or more axes.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a general rotating machine using magnetic bearings, Fig. 2 is a block diagram of an embodiment of the present invention, and Fig. 3 is a block diagram of a general rotating machine using magnetic bearings.
The figure is a top sectional view of the dual-purpose electromagnet of the present invention. In Figure 1, 1 is a rotating body, 2, 3, 4, 5
are the yoke, rotor, excitation coil, and position detector of the axial magnetic bearing, respectively; 6, 7, 8, and 9 are the yoke, rotor, excitation coil, and position detector of the upper radial magnetic bearing, respectively; 11, 12, 13
18 is the housing case, 21 and 22 are the upper radial magnetic bearing/motor yoke and the rotor, and 23 and 24 are the upper radial magnetic bearing excitation coil and position detection, respectively. 25 is an excitation coil for the upper motor; 26 and 27 are lower radial magnetic bearing and motor yoke; 28 and 29 are excitation coils for the lower radial magnetic bearing; 30 is a lower motor yoke; This is the excitation coil.

Claims (1)

[Claims] 1. In magnetic bearings used in ultra-high-speed rotating machines, etc., the excitation coil of a three-phase induction motor and the excitation coil of a radial magnetic bearing are each applied to one yoke,
A magnetic bearing device characterized in that the single yoke is used to rotate and magnetically levitate a rotating body in the radial direction using each of the excitation coils.