JPS59219522A - Magnetic bearing - Google Patents

Abstract

PURPOSE:To miniaturize an electromagnet coil, by installing a mechanical bearing holding a rotor except at a time when the rotor is afloat or in time of emergency as well as installing such a mechanism as shifting the said bearing, capable of securing the rotor to its stabilized position in time of its being afloat. CONSTITUTION:The rotor side of a magnetic bearing 1 is made up of ringlike permanent magnets 5a and 5b set up at the upper and lower insides of a case 2 and each of yokes 8a and 8b installed so as to surround electromagnet coils 9a and 9b being wound in ring form set up in the central part of a hollow fixed shaft 4 locked by the case 2. On the other hand, a rotor 3 set up inside the case 2 is made up of each permanent magnets 6a and 6b set up so as to be opposed to magnets 5a and 5b at its upper and lower parts and a permanent magnet 7 installed in space between these yokes 8a and 8b. And, each of bearing 10a and 10b holding the rotor 3 is locked to sleeves 11a and 11b being slidably installed at both ends of the fixed shaft 4, and these sleeves 11a and 11b are made shiftable by rotation of a screw shaft 12.

Description

[Detailed Description of the Invention] [Four branch areas covered by the invention] The present invention I'''+: The rotor metal magnetic force fl (therefore, general magnetic bearings that are supported and rotated) [Prior art and the ; Vertex] As a method of fully supporting a rotor rotating at high speed, instead of the conventionally used mechanical bearings, a method of supporting the rotor by magnetic force (〆ζ) is known. Known magnetic bearings for supporting rotors are equipped with mechanical bearings to support the rotor when no magnetic force is applied to the rotor. In the case of a magnetic bearing that uses a fully-adhesive lock and permanent magnets, the permanent magnets of the rotor and the ferrule are aligned with each other to prevent the permanent magnets from adhering to the yoke 1111, and to prevent damage to the rotor and stator in an emergency. This is to avoid.

British Patent Gll 2056579A K, 1?
li! As shown, the rotor and the mechanical 111
If the gap in the first bridge is made smaller, the impact between the rotor and the rock sleeve bridge in an emergency can be reduced. However, since the rotor rotates while being supported non-tightly, the above-mentioned air gap f4j is limited due to manufacturing precision, resulting in the [T1' function] which obstructs the rotor. When magnetically levitating a rotor cut into a 1ψ bearing, the capacity of the power amplification ag, which is one component of the supply source that separates the 101 rotor approaching the permanent magnet, as described above, is This meant that the size of the entire device had to increase as well.
An example of using a mechanical bearing as part of a temporary fixing mechanism for a rotor as described in British Patent No. 2048195A, and then moving it after use and using it as a normal emergency bearing. 75: This 4P-type bearing movement mechanism simply rotates the rotor in the direction when no magnetic force is applied to the rotor, and when levitating, it uses a dense magnet coil as in the past. It required a large amount of current.

[Purpose of the invention]

The present invention was made for the above-mentioned point of view, and reduces the capacity of the power multiplier, which was determined by the amount of large current generated in the electromagnetic coil V when the rotor levitates, and The electromagnetic coil can be made smaller. An object of the present invention is to provide a magnetic bearing having a rotor movement mechanism using a mechanical bearing.

[Summary of the song of invention]

The present invention provides a magnetic bearing having a rotor and a source of magnetic force O1 for magnetically supporting the rotor, which has a mechanism for moving the rotor to a stable floating position of the rotor using the mechanical bearing. The reason lies in the structure of the magnetic bearing.

〔Effect of the invention〕

The capacity of the power amplifier can be reduced and the number of turns of the electromagnetic coil can be reduced, making it possible to downsize the entire device.

[Embodiments of the invention]

Hereinafter, typical embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view of a single-axis controlled magnetic bearing, which is one of the embodiments of the magnetic I1II bearing according to the present invention.

A radially magnetized permanent magnet (5a
) (sb), a hollow fixed shaft (4) fixed to the case (2) and provided with grooves for a movement mechanism of mechanical bearings (10a) (10b), which will be described in detail later, and the fixed shaft (4). ) is an electromagnetic coil (9
On the other hand, the rotor (3) inside the case (2) is composed of a pair of yokes (8a) and (8b) installed so as to sandwich the parts a) and (9b). (3)
Above and below the radially magnetized permanent magnets (5a,) (5b
radially magnetized permanent magnets (6a) (6b) with ring-shaped yokes fixed to the inner and outer peripheries.
A ring-shaped yoke arranged to face the pair of yokes (sa') and (sb) is structured by radially magnetized permanent magnets (7) attached simultaneously to the inner and outer peripheries. ing. The axial magnetic control of the rotor (3) is performed as follows.

The axial displacement of the rotor (3) is defined as the displacement i! 't (15), this detection signal is processed by a control device (not shown), amplified by a power amplifier (not shown), and applied as a current to the electromagnetic coils (9a) (9b), thereby combining the force of the permanent magnet and the electromagnet. The rotor (3) is floated to a stable position by balancing the forces. The radial control of the rotor (3) is controlled by the permanent magnets (6)
a) It is actively controlled by the attractive force of the permanent magnets (5a) (5b) placed above and below the case (2).

The rotor (3) is attracted to either the top or bottom when no magnetic force is applied to the rotor (3), but if the permanent magnets are completely aligned with each other, then when the permanent magnets and the yoke are attracted, the electric and magnetic Since it is difficult to levitate the stones by force, it is necessary to provide a certain gap between the Mizukuhaku stones or between the permanent magnet and the yoke. For this reason, mechanical bearings (1 oa) (Job
) are arranged above and below the rotor (3).

Fixed to the aforementioned mechanical bearings (10a) (10b),
movable sleeves (11a) (11b) movable in the axial direction of the hollow fixed shaft (4) and threaded on the inside;
and a threaded shaft u'4 which is threaded at a position corresponding to the threaded portion of the movable sleeve inside the fixed shaft (4). Furthermore, the moving sleeve (lla)
The screw (llb) is the upper tool screw, that is, if the movable sleeve (11a) is a right-hand thread, the movable sleeve (11b)
is a left-handed screw, and the upper and lower screws of the threaded shaft o21 are the same screw.

Next, the movement of the rotor (3) to the stable floating position will be explained.

When the threaded shaft (1) is rotated in the direction of arrow j13, the direction of the screw changes in the moving sleeve (lla) (1).
1b) move in the directions of arrows (14a) and (14b), respectively.

Therefore, the mechanical bearing (1oa) (Job) moves in a direction to sandwich the rotor (3), thereby moving the rotor (3) to a stable floating position. After the rotor (3) has floated, the mechanical bearings (10a) and (10b) can be removed by rotating the screwed bearing (1) in the opposite direction and performing the same operations as described above.
to a position where it does not interfere with the rotation of the rotor (3).

In this way, in the magnetic 1411 bearing that breaks the mechanism of moving the rotor (3) to a stable floating position by the mechanical bearings (10a) (1ob), the electromagnetic coil generated at the start of floating of the rotor (3) @h The peak current that flows can be suppressed to a low level, the power increaser which was determined by this peak current can be reduced, and the number of turns of the electromagnetic coil can be increased.

Figure 2 shows the time variation of the current flowing into the electromagnetic coil when the permanent magnet combination type magnetic bearing starts floating. At the start of levitation, the d1 current value exceeds IOA, but when levitation stabilizes, almost no current flows. As is clear from FIG. 2, the above-mentioned effectiveness is remarkable, and by using a mechanical IIIll bearing in the moving mechanism, the magnetic bearing can avoid damage to the components of the magnetic bearing in the event of an emergency.

The above-mentioned moving mechanism using the mechanical bearing sound of the trochanter is the first
The structure is not limited to the structure shown in the figure, and any other method may be used as long as the rotor can be moved to a stable floating position. Fig. 3 1d shows another embodiment of the present invention.
The number of control axes is different from the magnetic bearing shown in the figure, and it is a two-control type magnetic bearing that controls two axes in the radial direction. Figure 3 is a cross-sectional view showing only one of the two radial axes. It comes out from the case (2υ), passes through the stator thin yoke (23a) fixed to the rotor (2υ), and from the rotor (2υ) yoke (22a) to the inner stator side yoke (23b).
9. The magnetic flux returning to the S beam of the permanent magnet is transferred to the electromagnetic coil (:?4
a) (24b) increases and decreases to float the rotor 12B to a stable position.

The rotor (Flu) is placed in a position corresponding to the threaded shaft (G) and this threaded part, and is moved in the direction of the axial force of the screw shaft (T). SpjJ-sp (26aX26b) and the moving sleeve (26a) (2
6b) support rods (28a) (28b) supported by bottles;
(30a) (30b) and mechanical bearings (32a) (32h) (34a) (34b)
Fix the inner ring of the (7) positioning shaft (27a) to both ends (27
c) and a grooved shaft (:3η) that prevents rotation of the moving sleeves (26a) and (26b).

If the moving sleeve (26a) has a right-handed thread, the moving sleeve (26b) has a left-handed thread, so that the moving sleeves (26a) and (26b) have different threads. 36) is composed of a one-way screw. FIG. 3 shows the above-mentioned mechanical
Two positioning shafts are drawn for convenience, but in reality at least three are required.

The method of moving the rotor (to two stable floating positions will be explained in Fig. 4). Fig. 4 shows the A section of Fig. 3, and the same members are designated by the same reference numerals for detailed explanation. Explanation will be omitted.

When the screwed +111+ (36) is rotated in the direction of arrow (41), the aforementioned 1# moving sleeve (26a) (261)
) moves in the directions of arrows (39a) and (39b) in FIG. By the movement of the moving sleeves (25a) (26b), the pin-supported support rods (28a) (28b)
, (29a) (29b) (30a) (30b) (31a
) (31b), and as a result, the pre-alignment IW determining shafts (27a) (27b) supported by pins on the support rods
(27C) (27d) is the arrow (38a) (38b)
(38c) moves the same distance in the direction of (38d),
Said positioning la, b (27a) 27b) (27c
) (27d) mechanical bearing (32a) (3
2b), (33a)(33b), (34a)(3
4b), (35a) (35b) moves the rotor (22) to a stable floating position.

Note that the above-mentioned moving mechanism is not limited to the structure shown in FIGS. 3 and 4, and any other method may be used as long as the rotor can be moved to the stable floating position. The present invention can also be applied to a magnetic bearing having three or more control shafts by combining the mechanisms shown in FIGS. 1 and 3.

As mentioned above, in the example of a magnetic bearing having a mechanism for moving the rotor to a floating stable position using a mechanical bearing, the first
Similarly to the figure, the capacity t of the power amplifier can be made smaller, the winding of the electromagnetic coil can be made thinner, and the number of turns can be reduced. Furthermore, since the movement mechanism uses an emergency bearing, damage to the components of the magnetic bearing in an emergency can be avoided, resulting in a compact and highly reliable magnetic bearing as a whole.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a magnetic bearing according to the present invention, and FIG. 2 is a sectional view of a magnetic bearing according to the present invention.
A characteristic diagram showing temporal changes in the M flow flowing through the electromagnetic coil when the rotor of a conventional magnetic bearing is levitating; FIG. 3 is a sectional view showing another embodiment of the present invention; FIG. FIG. (1) Magnetic bearing (single shaft system @ J type) (2) Case% (3) Rotor, (4) Fixed shaft (
5a) (5b). (6a) (6b), (7) - Ring-shaped permanent magnet, (sa
)(8b) -Yoke, (9a)(9b)-Electromagnetic coil, (10a)(10b)...Mechanical bearing, (Ha)(
Hb)...Moving sleeve, (IJ...Threaded shaft, (
2I magnetic bearing (2-axis control type), Cυ... case, t23
-=Rotor, (23a) (23b)...Yoke, (24a
)(24b)...Electromagnetic coil, (2 groups of ring-shaped permanent magnets, (26a)(26b)...Transferable sleeve, (
27a) (27b) Positioning axis, (28a) (28
b) (29a) (29b) (30a) (30b) (31
a) (31b) ...Support rod, (32a) (32b)
(33a) (33')) (34a) (34b) (35
a) (35b) Mechanical bearing, Saki... threaded shaft, (37
1,, Grooved Axis Agent Patent Attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 8 Figure 4 Figure 165-

Claims (1)

[Claims] In a magnetic bearing that has a rotor and a strong magnetic force supply that magnetically supports the rotor, is there a mechanical bearing that holds the rotor in an emergency, not only during magnetic levitation of rotation? 1. A magnetic bearing, characterized in that it has a mechanism for moving the mechanical bearing, which can identify the rotor component to a stable position when the rotor has a magnetic float.