JPH0785638B2 - Rotating electric machine with magnetic bearing - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary electric machine having a magnetic bearing, and more specifically, a magnetic bearing for moving a rotating shaft in an axial direction and a radial direction during rotation of the rotating shaft. The present invention relates to a rotating electric machine.

[Background of the Invention]

Conventionally, this type of rotary electric machine has been used in a vibration cutting device or the like as shown in Japanese Patent Laid-Open No. 58-71003, and a processing tool is attached to the tip of the rotary shaft to make the rotary shaft axial and radial. It is configured so that it can be moved and the processing tool can cut the workpiece. That is, as shown in FIG. 8, a rotary electric machine having a conventional magnetic bearing has a rotating shaft 1,
Motor 2 and two radial magnetic bearings 3, 4 and 1
And two magnetic bearings 5 for axial movement.

The motor 2 is composed of a rotor 21 mounted on the outer surface of the rotary shaft 1 and a stator 22 mounted inside the case 6 and arranged in the outer peripheral direction of the rotor 21.
The radial moving magnetic bearings 3 and 4 are installed on both sides of the motor 2 in the axial direction. This radial moving magnetic bearing 3,
4 are magnetic bodies 31 and 41 each of which is attached to the outer surface of the rotary shaft 1 and is made of a magnetic material, and is attached to the inside of the case 6 and arranged in the radial direction of the magnetic bodies 31 and 41 (vertical direction in the figure). The magnetic force parts 32 and 42 that are attached to the case 6 and magnetic force parts (not shown) that are attached to the case 6 and that are arranged in a direction intersecting with the magnetic force parts 32 and 42 of the magnetic bodies 31 and 41 (in the front and back paper direction in the figure). There is. The magnetic bearing 5 for axial movement is attached to one end of the rotary shaft 1 and has a disk-shaped magnetic body 51 made of a magnetic material. The magnetic field portion 52 is attached to the magnetic body 51 and faces the magnetic body 51 so as to sandwich the magnetic body 51. Reference numeral 10 is a machining tool attached to the other end of the rotary shaft.

A rotary electric machine having this magnetic bearing has two magnetic bearings for radial movement 3, 4 and a magnetic bearing part 32 of the magnetic bearing 5 for axial movement.
42, 52 are excited, and the magnetic bodies 31, 41, 51 are attracted to these to support the rotary shaft 1 as shown in the drawing. At this time, the stator 22 and the rotor 21 of the motor 2 prevent the rotary shaft 1 from moving. It is supposed to be rotated. Then, during rotation of the rotary shaft 1, for example, by magnetically increasing the magnetic force portions 32 and 42 of one of the two radial direction magnetic bearings 3 and 4, and attracting the magnetic bodies 31 and 41, The rotating shaft 1 is vibrated in the vertical direction, and the magnetic force part (not shown) on the other side is magnetized.
When 1 is sucked, the rotating shaft 1 can be vibrated in the vertical direction and the crossing direction. Further, in the magnetic bearing 5 for axial movement, one of the magnetic force portions 52 is magnetized, and the magnetic body 51 is attracted to the magnetic force portion 52, so that the rotary shaft 1 can be moved in the axial direction. I'm running.

Therefore, the two radial direction magnetic bearings 3 and 4 and the axial direction magnetic bearing 5 are respectively provided with dedicated position detectors 7, 8 and 9 and detection signals from these position detectors 7, 8 and 9. The control unit independently controls the exciting force of each magnetic force unit 32, 42, 52 based on Position detector 7,8,9
Have targets 7a, 8a, 9a at positions facing each other, and are configured to be able to detect a gear gap between the targets 7a, 8a, 9a. Since the control units have substantially the same configuration, the magnetic bearing 5 for axial movement will be described here. That is, when the rotary shaft 1 is moved in the axial direction,
As shown in FIG. 9, the detection signal from the position detector 9 is input to the comparator 12 via the phase lead compensation circuit 11. The comparator 12 compares the input signal based on the detection signal with the input signal of the set value in which the movement amount is set in advance by the gear setter 13 to obtain the deviation, and the proportional-integral circuit 14, An exciting current according to the deviation is applied to the magnetic force section 52 through the width device 15 and the deviation becomes 0 according to the movement of the rotating shaft 1 to move the rotating shaft 1 to the target position.

By the way, in the conventional example shown above, the magnetic bearing 5 for axial movement is designed to attract the magnetic body 51 between the coil portions forming the magnetic force portions 52 arranged to face each other in the axial direction. Since it is configured, the amount of movement of the rotary shaft 1 in the axial direction is limited by the length of the gap between the magnetic body 51 and the magnetic force parts 52, 52, and therefore there is a problem that the amount of movement is extremely small. .

In order to solve this problem, a feed mechanism that can move the entire rotary electric machine was separately provided, but in that case, not only the feed mechanism is complicated and large, but also the cost becomes higher.

[Object of the Invention]

In view of the above circumstances, an object of the present invention is to prevent the amount of axial movement of the rotary shaft from being restricted by the gear cup, so that the amount of axial movement of the rotary shaft is large without separately providing a feed mechanism. The present invention provides a rotating electric machine having a magnetic bearing that can be used.

[Outline of Invention]

As a result of various studies and tests, the present inventors have found that in order to make the moving amount of the rotating shaft larger than the gear length between the magnetic body and the magnetic force part of the magnetic bearing for axial movement, the gear length is Attention was paid not to provide in the axial direction but to provide in the direction orthogonal to this, that is, in the radial direction. In other words, when the gear length is provided in the radial direction, when the magnetic force section is excited, the magnetic force produces two component forces on the magnetic body in the radial direction and the axial direction. Use the magnetic force in the axial direction. I focused on.

That is, a rotary electric machine having a magnetic bearing of the present invention has a magnetic bearing for axial movement, a magnetic body attached to a peripheral surface of a rotary shaft, and a magnetic body installed on an outer peripheral portion corresponding to the magnetic body. It has a radial gear and is composed of a magnetic part that can attract the magnetic body in the axial direction when excited, and expands the magnetic body that constitutes the magnetic bearing for radial movement in the axial direction and moves it in the radial direction. The present invention is characterized in that the target of the position detector of the magnetic bearing for use is expanded in the axial direction.

Example of Invention

Hereinafter, some embodiments of the present invention will be described with reference to FIGS. 1 and 2 show a first embodiment of a rotary electric machine having a magnetic bearing according to the present invention, in which the same reference numerals as those in FIGS. 8 and 9 denote the same or corresponding ones. It represents.

A rotary electric machine having a magnetic bearing of the embodiment includes a rotary shaft 1, a rotor 21 attached to an outer surface of the rotary shaft 1, and the rotor 21.
A motor 2 constituted by a stator 22 arranged in the outer peripheral direction of 21, at least two radial direction magnetic bearings 3 and 4 for moving the rotating shaft 1 in the radial direction, and moving the rotating shaft 1 in the axial direction. At least one magnetic bearing 5 for axial movement is provided. This point is similar to the conventional example.

The magnetic bearing 5 for axial movement is composed of a magnetic body 51 attached to the peripheral surface of the rotary shaft 1 and two magnetic force portions 52a and 52b arranged in the outer peripheral direction of the magnetic body 51. ing.

Specifically, the magnetic body 51 is formed into a cylindrical shape having a proper outer diameter and length (thickness) by laminating thin magnetic plates such as a silicon rigid plate, and has a rotating shaft inside thereof. 1 is fitted and attached to one end of the rotary shaft 1.

The magnetic force portions 52a and 52b each attract the magnetic body 51, and are composed of, for example, a core and a coil wound so as to surround the core. The magnetic force portions 52a and 52b are formed in a cylindrical shape having an inner diameter larger than the outer diameter dimension of the magnetic body 51, are attached to the inner surface of the case 6, and are arranged in the outer peripheral direction of the magnetic body 51. Therefore, the respective magnetic force portions 52a and 52b have gears in the direction perpendicular to the axis with respect to the magnetic body 51, that is, in the radial direction.

Further, in the magnetic force parts 52a and 52b, the magnetic center parts of the magnetic parts
Are arranged to face each other along the axial direction of the rotating shaft 1 so as to be displaced from the central portion of the. When either one of them is excited, the magnetic force of the two component forces of the radial direction and the axial direction acts, and the magnetic body 51 is attracted by the magnetic force in the axial direction, so that the magnetic body 51 is removed. It can be moved in the axial direction.

Therefore, the magnetic force in the axial direction of the magnetic force unit 52 is controlled by the position detector 9 for axial movement and the control unit. The position detector 9 has a target 9a attached to the inner surface of the case 6 at a position facing the rotary shaft 1 and fixed to one end surface of the rotary shaft 1, and a gear gap between the target 9a and the target 9a is provided. It is configured for detection. In the control section, the output section of the position detector 9 is connected to the comparator 12 via the phase compensation circuit 11.
One of the input sections is connected to the other input section of the comparator 12, and the gear setter 13 is connected to the other input section of the comparator 12. The gear setting device 13 sets the gear between the position detector 9 and its target 9a. The output of the comparator 12 includes the magnetic force unit 52a via the comparison and integration circuit 14 and the amplifier 15 and the magnetic force unit via the inverter 17, the proportional integration circuit 14, and the amplifier 15.
52b is connected in parallel.

That is, when the comparator 12 outputs the deviation between the detection signal from the position detector 9 and the command value signal of the gear setter 13 by the comparator 12, the output signal on one side remains unchanged as it is on the proportional-integral circuit. 14 and the magnetic force part 52a via the amplifier 15, and the other side is inverted in polarity by the inverter 17, so that it is input to the magnetic force part 52b via the same route as above. Therefore, in the control circuit, when the rotating shaft 1 moves away from the set position, one magnetic force part 52b is magnetized and the other magnetic force part 52a is demagnetized, and when the rotary shaft 1 is contracted from the set position, the other magnetic part 52b is demagnetized. The magnetic force part 52a is magnetized and one magnetic force part 52b is demagnetized, and thus the rotating shaft 1
Can be controlled to move to a desired position.

As described above, in the rotating electric machine of the present embodiment, the magnetic body 51 and the magnetic force portions 52a and 52b of the magnetic bearing 5 for axial movement have the radial gears, and either one of the magnetic force portions 52a and 52b is provided. Since the magnetic body 51 is moved in the axial direction by increasing the magnetism and demagnetizing the other, the rotating shaft 1 can be reliably moved in the axial direction. Therefore, as compared with the conventional magnetic bearing 5 having a gear length in the axial movement direction, the movement amount of the rotary shaft 1 is not limited to the gear length, so that the movement amount of the rotary shaft 1 in the axial direction is not limited. Can be larger.

Further, when the amount of movement of the rotary shaft 1 in the axial direction is large, the position detectors 7, 8 for detecting the positions of the radial movement magnetic bearings 3, 4 are detected.
Since the targets 7a and 8a of the above are largely displaced in the axial direction, the position detectors 7 and 8 may not be able to detect accurately. However, in this example, since the respective targets 7a and 8a are expanded in the axial direction to have a length (thickness) larger than that of the conventional one, even if the targets 7a and 8a are biased in the axial direction, the accurate position can be maintained. In addition to this, since the magnetic bodies 31, 41 of the radial movement magnetic bearings 3, 4 are also expanded in the axial direction, even if the axial movement amount of the rotary shaft 1 is large, the magnetic force for radial movement is large. The rotating shaft 1 can be reliably moved to a desired position in the radial direction by the bearings 3 and 4.

FIG. 3 shows a second embodiment of the present invention. This embodiment differs from the first embodiment in that the magnetic force portions 52a and 52b of the axially moving magnetic bearing 5 are solenoids and the magnetic body 51 is magnetized like a permanent magnet. It is in the point of using things. Therefore, this embodiment can basically obtain the same effect as that of the first embodiment.

4 and 5 show a third embodiment of the present invention. In this case, a plurality of magnetic bodies 51 of the axial moving magnetic bearing 5 are arranged along the axial direction with respect to the peripheral surface portion of the rotary shaft 1,
In addition, a plurality of magnetic force portions 52 are spirally arranged along the axial direction. That is, each of the plurality of magnetic bodies 51 has the same outer diameter and length (thickness), and is attached to the rotary shaft 1 along the axial direction with an appropriate interval. Each of the plurality of magnetic force portions 52 is attached to a position surrounding the magnetic body 51 inside the case 6, and is spirally arranged along the axial direction of the rotating shaft 1. The magnetic bearing 5 has a magnetic force section.
When each of 52 is sequentially excited and demagnetized along the axial direction, the excited magnetic force portion 52 attracts the magnetic body 51, thereby moving the magnetic body 51 in the axial direction, and thereby the rotating shaft. 1 can be moved in the axial direction. Therefore, each of the plurality of magnetic force units 52 is configured to be independently turned on and off.

FIG. 6 shows a fourth embodiment of the present invention. In this case, two magnetic bearings 3 and 4 for radial movement are used as the magnetic bearing 5 for axial movement.

That is, the magnetic body 51 of the magnetic bearing 5 is the magnetic body 31, 41 of the magnetic bearing 3, 4, and the magnetic force portion 52 of the magnetic bearing 5 is the magnetic bearing.
The magnetic members 32 and 42 of 3 and 4 are respectively configured, and the magnetic body 51 and the magnetic center of the magnetic unit 52 are arranged so as to be displaced in the axial direction.

Then, of the two magnetic bearings 3 and 4, the magnetic force parts 32 and 42 of either one of the magnetic bearings 3 and 4 are magnetized, and the magnetic bodies 31 and 41 are
Is attracted, the magnetic bodies 31 and 41 are moved in the axial direction.

Therefore, in this embodiment, two magnetic bearings for radial movement are used as the magnetic bearing 5 for axial movement, so that the number of parts is reduced as compared with the first to third embodiments described above. The cost can be reduced accordingly.

FIG. 7 shows a fifth embodiment of the present invention. In this embodiment, the motor 2 is used as a magnetic bearing for axial movement. That is, in the magnetic bearing 5 in this case, the magnetic body 51 is constituted by the rotor 21 of the motor 2, the magnetic force portion 52 is constituted by the stator 22 of the motor 2, and the rotor 21 is
And the stator 22 are relatively displaced from each other in the axial direction. Then, by changing the magnetic force of the stator 22 with respect to the rotor 21 and attracting the rotor 21 to this, the rotor 21 can be moved in the axial direction.

Therefore, in this embodiment, since the motor 2 is used as the magnetic bearing 5 for axial movement, the number of parts is the same as that of the fourth embodiment as compared with the first to third embodiments described above. In addition to reducing the cost, the cost can be reduced, and when this rotating electric machine is used upright, a thrust load acts on the rotating shaft 1, but the thrust force is generated by the magnetic attraction between the rotor 21 and the stator 22. Since it can be relaxed, magnetic bearings 3,
You can also reduce the load on 4,5.

〔The invention's effect〕

As described above, according to the present invention, the magnetic bearing for axial movement is attached to the peripheral surface of the rotating shaft, and the magnetic body is installed at a position corresponding to the outer peripheral portion of the magnetic body. It has a gear in the radial direction and is composed of a magnetic force part capable of attracting the magnetic substance in the axial direction when excited, so that the amount of axial movement of the rotary shaft can be adjusted between the magnetic substance and the magnetic force part. Can be increased without being restricted by the gear length of the radial movement, the magnetic body forming the radial movement magnetic bearing can be expanded in the axial direction, and the target of the position detector of the radial movement magnetic bearing can be set in the axial direction. Therefore, even if the amount of movement of the rotary shaft in the axial direction is large, the radial movement position of the rotary shaft can be accurately detected, and the rotary shaft can be reliably moved to the desired radial position. it can. Therefore, according to the present invention, since it is not necessary to separately provide a feeding mechanism, it is possible to make it compact, and
It is also economical and has a non-contact feed structure.
Since there are no worn parts, there are advantages such as easy maintenance.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a rotary electric machine having a magnetic bearing of the present invention, FIG. 2 is a control circuit diagram of a magnetic bearing for axial movement, and FIG. 3 is a magnetic bearing of the present invention. Sectional drawing which shows the 2nd Example of a rotary electric machine, FIG. 4 is sectional drawing which shows the 3rd Example of the rotary electric machine which has the magnetic bearing of this invention, 5th
FIG. 7 is a sectional view taken along line VV of FIG. 4, FIG. 6 is a sectional view showing a fourth embodiment of a rotating electric machine having a magnetic bearing of the present invention, and FIG.
The drawing is a sectional view showing a fifth embodiment of a rotating electric machine having a magnetic bearing of the present invention. FIG. 8 is a sectional view showing an example of a rotary electric machine having a conventional magnetic bearing, and FIG. 9 is a control circuit diagram of a conventional magnetic bearing for axial movement. 1 ... Rotary axis, 2 ... Motor, 21 ... Rotor, 22 ... Stator, 3,4 ... Radial direction magnetic bearing, 31,41 ... Magnetic material, 32,42 ... Magnetic part, 5 ...... Axial movement magnetic bearing, 51 ...... Magnetic body, 52 ...... Magnetic part, 7,8 ...... Radial movement magnetic bearing position detector, 7a, 8a ...... Target, 9
...... Axial movement magnetic bearing position detector, 9a ...... Target.

Continuation of the front page (56) References JP-A-59-99947 (JP, A) JP-A-59-219523 (JP, A) Actually developed JP-A-59-173459 (JP, U)

Claims (6)

[Claims] 1. A motor comprising a rotating shaft, a rotor attached to an outer surface of the rotating shaft, and a stator arranged at an outer peripheral position of the rotor, and at least one axial direction for moving the rotating shaft in the axial direction. It has a moving magnetic bearing, at least two radial moving magnetic bearings for moving the rotating shaft in a direction orthogonal to the shaft, and a target attached to the outer surface of the rotating shaft, and has a radius at a position facing the target. Position detector of the magnetic bearing for radial movement, which is arranged along the direction through a gap, and a target mounted on one end face of the rotating shaft, and is arranged at a position facing the target along the axial direction through the gap. The magnetic bearing position detector for axial movement, the magnetic bearing position detector for radial movement and the magnetic bearing position detector for axial movement detect the magnetic bearings. In a rotary electric machine having a magnetic bearing including a control unit for independently controlling force, the magnetic bearing for axial movement includes a magnetic body attached to a peripheral surface of a rotary shaft, and an outer peripheral portion of the magnetic body. It is arranged at the corresponding position and has a gap in the radial direction with respect to the magnetic body,
And a magnetic body that is capable of attracting a magnetic pair in the axial direction when excited, expands the magnetic body constituting the magnetic bearing for radial movement in the axial direction, and detects the position of the magnetic bearing for radial movement. A rotary electric machine having a magnetic bearing, characterized in that the target of a container is expanded in the axial direction. 2. A magnetic bearing portion of an axially moving magnetic bearing according to claim 1, wherein the magnetic center portion of the magnetic bearing portion is opposed to the magnetic bearing portion along the axial direction of the rotating shaft so that the magnetic center portion of the magnetic bearing portion is displaced from the center portion of the magnetic body. A rotating electrical machine having a magnetic bearing characterized by the above. 3. A rotary bearing having a magnetic bearing according to claim 2, wherein the magnetic force portion of the magnetic bearing for axial movement is constituted by a solenoid and the magnetic body is constituted by a permanent magnet. Electric machinery. 4. The magnetic bearing for axial movement according to claim 1, wherein a plurality of the magnetic bodies are arranged at intervals in the axial direction of the rotary shaft, and the magnetic force portions are arranged in the axial direction of the rotary shaft. A rotating electric machine having a magnetic bearing, wherein a plurality of the magnetic bearings are arranged along the spiral. 5. The magnetic bearing for axial movement according to claim 1, wherein the magnetic bodies are composed of magnetic bodies of the magnetic bearings for radial movement, and the magnetic force portions are provided in respective radial directions. A rotating electric machine having a magnetic bearing, which is constituted by a magnetic force portion of a moving magnetic bearing. 6. The magnetic bearing for axial movement according to claim 1, wherein the magnetic body is a rotor of a motor and the magnetic force section is a stator of the motor.
A rotating electric machine having a magnetic bearing, wherein the stator and the rotor are relatively displaced in the axial direction.