JPS61185039A - Rotary electric machine having magnetic bearing - Google Patents

Abstract

PURPOSE:To increase the axial moving distance of a rotational shaft by composing a magnetic bearing for axially moving of a magnetic unit mounted on the periphery of a rotational shaft and a magnetic force unit capable of axially attracting the magnetic unit. CONSTITUTION:A rotary electric machine has a motor 2 in which has a rotor 21 mounted on the outer surface of a rotational shaft 1 and a stator 22 disposed in the outer circumferential direction of the rotor 21, radially moving magnetic bearings 3, 4 for radially moving the shaft 1, and an axially moving magnetic bearing 5 for moving axially the shaft 1. The bearing 5 is composed of a magnetic unit 51 mounted on the periphery of the shaft 1 and magnetic force units 52a, 52b disposed in the outer circumferential direction of the unit 51.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a rotating machine having a magnetic bearing, and more specifically, to a rotating shaft having a magnetic bearing, and more specifically, to a rotating shaft having a magnetic bearing, the rotating shaft is moved in the axial direction and the radial direction while the rotating shaft is rotating. The present invention relates to a rotating electric machine equipped with a magnetic bearing.

[Background of the invention]

Conventional rotating electric machines of this type are used in vibration cutting equipment, etc., as shown in Japanese Patent Laid-Open No. 58-71003, and a machining tool is attached to the tip of the rotating shaft, and the rotating shaft is rotated in the axial and radial directions. The machining tool is configured to be able to cut the workpiece by moving the machining tool to the position shown in FIG. That is, as shown in FIG. 8, a conventional rotating machine with magnetic bearings has a rotating shaft 1, a motor 2, and two magnetic bearings 3 for radial movement.
, 4, and one magnetic bearing 5 for axial movement.

The motor 2 includes a rotor 21 attached to the outer surface of the rotating shaft 1 and a rotor 21 attached to the inside of the case 6.
The stator n is arranged in the outer circumferential direction of the stator n. The magnetic bearings 3 and 4 for radial movement are installed on both sides of the motor 2 in the axial direction. The magnetic bearings 3 and 4 for radial movement include magnetic bodies 31 and 41, each of which is attached to the water surface of the rotating shaft 1 and made of a magnetic material, and a radius of the magnetic bodies 31 and 41 which is attached to the inside of the case 6. magnetic force parts 32 and 42 arranged in the direction (vertical direction in the figure);
It is attached to the case 6 and crosses the magnetic parts 32 and 42 of the magnetic bodies 31 and 41 (in the direction of the front and back paper in the case).
It consists of a magnetic force section (not shown) located at The magnetic bearing 5 for axial movement includes a magnetic body 51 which is attached to one end of the spindle 1 and formed into a disc shape from a magnetic material, and a magnetic body 51 which is attached to the inner side of the case 6 in the axial direction of the spindle 1. It consists of magnetic force parts 52 that are arranged opposite to each other so as to sandwich a magnetic body 51 . Note that IO is a processing tool attached to the other end of the rotating shaft.

The rotation tm having this magnetic bearing excites the magnetic force parts 32 , 42 , 52 of the two magnetic bearings 3 and 4 for radial movement and the magnetic bearing 5 for axial movement, so that the magnetic body 31
, 41, and 51 support the rotary shaft 1 as shown in the figure, and the rotary shaft 1 is rotated by the stator of the motor 2 and the rotor 21 at this time. During the rotation of the rotating shaft 1, for example, one of the magnetic force parts 32 of the two radially moving magnetic bearings 3.
, 42 are magnetized, and the magnetic bodies 31 and 41 are attracted to them, thereby causing the rotary shaft 1 to vibrate in the vertical direction.The other magnetic force part (not shown) is also magnetized, and the magnetic bodies 31 and 41 are attracted thereto. 31
, 41 are attracted, so that the rotating shaft 1 can be vibrated in the vertical direction and the cross direction. Furthermore, in the magnetic bearing 5 for axial movement, by magnetizing one of the magnetic parts 52 and attracting the magnetic body 51 to this, the rotating shaft 1 can be moved in the axial direction. It has become.

Therefore, the two magnetic bearings 3° 4 for radial movement and the magnetic bearings 5 for axial movement are equipped with dedicated position detectors 7 and 8, respectively.
and 9, and a control section that independently controls the excitation force of each magnetic force section 32, 42, 52 based on detection signals from these position detectors 7.8.9. The position detectors 7, 8.9 are located at opposite positions (7m, 8a).

9a, and is configured to be able to detect a gap between the target and the target. Since each of the control sections has substantially the same S configuration, the magnetic bearing 5 for axial movement will be described here. That is, when moving the rotating shaft 1 in the axial direction, a detection signal from the position detector 9 is input to the comparator 12 via the phase lead compensation circuit 11, as shown in FIG. The comparator 12 compares the input signal based on the detection signal with the input signal of the set value whose movement amount is set in advance by the gear foot foot device 13, calculates the deviation, and calculates the deviation thereof. 15tl-through magnetic force section 52
An excitation current corresponding to the deviation is applied to the rotating shaft 1.
When the deviation becomes O in accordance with the movement of , the rotating shaft 1 is moved to the target position k.

By the way, in the conventional example shown above, the magnetic bearing 5 for axial movement is configured to attract the magnetic body 51 between the coil parts 52, 52 arranged opposite to each other in the axial direction.
The amount of axial movement of the rotating shaft 1 is determined by the magnetic body 51 and the magnetic force part 52.
, 52, and therefore the amount of movement is extremely small.

In order to solve this problem, a separate feed mechanism was provided that could move the entire rotation 11@, but in that case, not only would the feed mechanism become complicated and large, but it would also be costly. be.

[Purpose of the invention]

In view of the above circumstances, an object of the present invention is to prevent the axial movement of the rotating shaft from being limited by the gap, so that the amount of axial movement of the rotating shaft can be increased without separately providing a feed mechanism. An object of the present invention is to provide a rotating electrical machine having a magnetic bearing capable of

[Summary of the invention]

As a result of extensive examination and testing, the present inventors found that in order to make the amount of movement of the rotating shaft larger than the gap length between the magnetic body and the magnetic part of the magnetic bearing for axial movement, the gap length must be Attention was focused on providing the radial direction not in the axial direction, but in a direction perpendicular to the axial direction, that is, in the radial direction. When the pick and gap lengths are set in the radial direction, when the magnetic part is excited, the magnetic force generates two component forces in the radial direction and axial direction on the magnetic body, but the axial magnetic force is used. I focused on this.

That is, in the rotating electric machine having a magnetic bearing of the present invention, the magnetic bearing for axial movement has a magnetic body attached to the peripheral surface of the rotating shaft, and a magnetic body installed on the outer peripheral part corresponding to the magnetic body. It is characterized by having a gap in the radial direction and a magnetic force section that can attract the magnetic material in the axial direction when it is pulled out.

[Embodiments of the invention]

Some embodiments of the invention will now be described with reference to FIGS. 1 to 7. FIGS. 1 and 2 show a first embodiment of a rotating tm having a magnetic bearing according to the present invention, and the same reference numerals as in FIGS. 8 and 9 represent the same or equivalent parts. ing.

The rotating electrical machine having a magnetic bearing according to the embodiment includes a rotating shaft 1, a rotor 21 attached to the outer surface of the rotating shaft 1, and a motor 2 consisting of a stator disposed in the outer circumferential direction of the rotor 21. , at least two radially moving magnetic bearings 3.4 for moving the rotating shaft 1 in the radial direction, and the rotating shaft 1.
and at least one magnetic bearing 5 for axial movement. This point is similar to the conventional example.

The magnetic bearing 5 for axial movement is constructed of a nine magnetic body 51 attached to the circumferential surface of the rotating shaft 1, and two output parts 52m and 52b arranged in the outer circumferential direction of the magnetic body 51. ing.

Specifically, the magnetic body 51 is formed into a cylindrical shape having an appropriate outer diameter, length, and thickness by laminating thin magnetic plates made of, for example, silicon rigid plates, and has a rotating shaft 1 inside it. is fitted to one end of the rotating shaft l.

The magnetic force parts 52m and 52b each attract the magnetic body 51, and are made of, for example, coils wound around a core. This magnetic force part 52at
52b has a cylindrical shape with an inner diameter larger than the outer diameter of the magnetic body 51, and is attached to the inner surface of the case 6.
They are arranged in the outer circumferential direction of the magnetic body 51. Therefore, each magnetic force part 52a, 52b has a gap with respect to the magnetic body 51 in the direction perpendicular to the axis, that is, in the radial direction.

Further, the magnetic force parts 52m and 52b are disposed opposite to each other in the axial direction of the rotating shaft 1 so that their respective magnetic centers are offset from the center of the magnetic body 51. When either one is excited, two force components in the radial direction and the axial direction act, and the magnetic body 51 is attracted in the axial direction by the magnetic force in the axial direction. It is now possible to move it to

Next, the axial magnetic force of the magnetic force section 52 is controlled by the position detector 9 for axial movement and the control a81S. The position detector 9 is mounted on the inner surface of the case 6 at a position facing the rotating shaft 1, and has a turret 9at fixed to one surface of the rotating shaft 1. It is configured to detect gaps between On the side (iI & 1 section, the output section of the position detector 9 is connected to one input section of the comparator 12 via the phase compensation circuit 11,
A cap setting device 13 is connected to the other input of the comparator 12 .

The gap setting device 13 is a position detector 9 and its target.)
Set a gap of -1 with 9m. And comparator 1
The magnetic force fi52m via the proportional-integral circuit 14 and the amplifier 15 and the magnetic force section 52b via the inverter 1b, the proportional-integral circuit 17 and the amplifier 18 are connected in parallel to the output section of 2. ing.

That is, the control section uses the comparator 12 to detect the position detector 9.
When the deviation between the detection signal from the gap setter 13 and the command value signal of the gap setter 13 is output, the output signal is directly transmitted to the magnetic force unit 5 via the proportional integral circuit 14 and the amplifier 15 on the one hand.
2 & and on the other hand, inverter 1
By having the polarity reversed by 6, the signal is input to the magnetic section 52b via the same route as above. Therefore, in this control circuit, when the rotating shaft 1 leaves the set position, one magnetic force section 52b is magnetized, and the other magnetic force section 52b is magnetized.
When m is demagnetized and contracted from the set position, the other magnetic force section 52 a is magnetized, and one magnetic force section 52 b
is demagnetized, thus making it possible to control the movement of the rotating shaft 1 to a desired position a.

As described above, in the rotating electrical machine of this embodiment, the magnetic body 51 of the magnetic bearing 5 for axial movement and the magnetic force parts 52m, 52b have a gap in the radial direction, and either one of the magnetic force parts 52m, 52b is The magnetic body 51 is magnetized while demagnetizing the other.
Since the rotating shaft 1 is moved in the axial direction, the rotating shaft 1 can be reliably moved in the axial direction.

Therefore, compared to the conventional magnetic bearing 5 which has a gap length in the axis movement direction, the amount of movement of the rotating shaft 1 is not limited by the gap length, so the amount of axial movement of the rotating shaft 1 can be reduced. It can be made much larger.

Furthermore, if the amount of axial movement of the rotary shaft 1 is large, the targets 7 a e 3 m of the position detectors 7 and 8 for detecting the positions of the magnetic bearings 3 and 4 for radial movement will shift greatly in the axial direction. , there is a risk that the position detectors 7 and 8 will not be able to detect accurately. However, in this example, each Targera)
7m, expanded in the axial direction to make it longer and thicker than the conventional one, so even if the target blades 7m and 8a shift in the axial direction, accurate position detection is possible.

FIG. 3 shows a second embodiment of the invention. −
This embodiment differs from the first embodiment as follows:
Magnetic force portions 52 a and 52 b of the magnetic bearing 5 for axial movement
is composed of a solenoid, and the magnetic body 51 is a magnetized material such as a permanent grinding stone.

Therefore, this embodiment can basically obtain the same effects as the first embodiment.

4 and 5 show a third embodiment of the invention. In this case, a plurality of magnetic bodies 51 of the magnetic bearing 5 for axial movement are arranged along the axial direction with respect to the curved surface of the rotating shaft 1,
A plurality of magnetic force parts 52 are arranged in a spiral shape along the axial direction. That is, the plurality of magnetic bodies 51 have the same outer diameter, length, and thickness, and are attached to the rotating shaft 1 at appropriate intervals in the axial direction. The plurality of magnetic parts 52 are each attached to a position surrounding the magnetic body 51 inside the case 6, and are arranged in a spiral shape overflowing in the axial direction of the rotating shaft 1. In the magnetic bearing 5, when each of the magnetic force parts 52 is sequentially excited and demagnetized in the axial direction, the excited magnetic force parts 52 attract the magnetic body 51, thereby causing the magnetic body 51 to axially move. move in the direction
This makes it possible to move it in the direction of the rotating shaft 1t-axis. Therefore, the above number of magnetic force parts 5
2. Is each individual on and off independently? I11.

FIG. 6 shows a fourth embodiment of the 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 S air bearing 5 is connected to the magnetic bearing 3.
4 magnetic bodies 31 and 41, and the magnetic force part 5 of the magnetic bearing 5
2 is composed of the magnetic force parts 32 and 42 of the magnetic axes 9!3 and 4, respectively, and the magnetic body 51 and the magnetic center part of the magnetic force part 52 are arranged so as to be shifted in the axial direction.

Then, the magnetic parts 32 and 42 of one of the two magnetic bearings 3 and 4 are magnetized, and the magnetic bodies 31 and 41 are attracted to this, so that the magnetic bodies 31, 41 It is adapted to be moved in the t-axis direction.

Therefore, since this embodiment uses two radially moving magnetic bearings as the axially moving magnetic bearing 5, the number of parts is reduced compared to the first to third embodiments described above. It is possible to reduce costs accordingly.

FIG. 7 shows a fifth embodiment of the invention.

This embodiment uses the motor 2 as a magnetic bearing for axial movement.
It is made using 1c. 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 output part 52 is constituted by the stator n of the motor 2, and the rotor 21 and the stator η are relatively axially misaligned. By changing the magnetic force of the stator η with respect to the rotor 21 and attracting the rotor 21 thereto, 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 reduced as in the fourth embodiment compared to the first to third embodiments described above. In addition to reducing costs, if this 11 rotary machine is used in a vertical tiltk, 1 rotary axis can be used.
A thrust load acts on the rotor 21 and the stator ρ.
The thrust force can be alleviated by modifying the magnetic attraction between the
It is also possible to reduce the load on the magnetic bearing 3°4.5.

〔Effect of the invention〕

As described above, the present invention provides that a magnetic bearing for axial movement is installed at a position corresponding to a magnetic body arranged on a curved surface of a rotating shaft, and an outer peripheral part of the magnetic body, and and a magnetic force section that has a gap in the radial direction and can attract the magnetic body in the axial direction when excited, so that the axial movement of the rotating shaft is controlled by the interaction between the magnetic body and the magnetic force section. It is possible to increase the gap length without being limited by the gap length between the two.

Therefore, according to the present invention, the feeding mechanism is separately provided.
Since this is no longer necessary, it can be made more compact and more economical, and since it has a non-contact feeding structure, there are no parts that wear out, so maintenance is easy.

[Brief explanation of the drawing]

Fig. 1 is a cross section showing a first embodiment of a rotating electric machine having a magnetic bearing metal according to the present invention. Fig. 2 is a control circuit diagram of a magnetic bearing for axial movement, and Fig. 3 is a cross-sectional diagram showing a first embodiment of a rotating electrical machine having a magnetic bearing according to the present invention. rotation tm
FIG. 4 is a cross-sectional view showing a second example of the magnetic bearing of the present invention, and FIG.
The figure is a sectional view taken along the line v-v in FIG. I! A sectional view showing an example,
FIG. 7 is a sectional view showing a fifth embodiment of a rotating electric machine having a magnetic bearing according to the present invention. FIG. 8 is a sectional view showing an example of a rotating electric machine having a conventional magnetic bearing, and the ninth factor is a control circuit diagram of a conventional magnetic bearing for axial movement. 1...Rotating shaft, 2...Motor, 21...Rotor,
n... Stator, 3, 4... Magnetic bearing for radial movement, 31° 41... Magnetic body, 32, 42... Magnetic force part, 5... Magnetic bearing for axial movement, 51. ...Magnetic material, 52...Magnetic force part. Representative Patent Attorney Tadashi Akimoto Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1. A motor comprising a rotating shaft, a rotor attached to the outer surface of the rotating shaft, and a stator disposed on the outer circumference of the rotor, and at least one motor for moving the rotating shaft in the axial direction.
In a rotating electric machine having a magnetic bearing including one magnetic bearing for axial movement and at least two magnetic bearings for radial movement that move a rotating shaft in a direction orthogonal to the axis, the magnetic bearing for axial movement includes: a magnetic body attached to the circumferential surface of the rotating shaft; the magnetic body is installed at a position corresponding to the outer circumference of the magnetic body, and has a gap in the radial direction with respect to the magnetic body;
A rotating electric machine having a magnetic bearing, characterized in that the rotating electric machine is constituted by a magnetic force part capable of attracting a magnetic material in the axial direction when excited. 2. A rotating electric machine having a magnetic bearing according to claim 1, wherein the magnetic force parts are arranged oppositely along the axial direction of the magnetic body. 3. A rotating electric machine having a magnetic bearing as set forth in claim 2, wherein the magnetic force section is constituted by a solenoid. 4. In claim 1, a plurality of the magnetic bodies are arranged at intervals in the axial direction of the rotating shaft, and a plurality of the magnetic parts are arranged in a spiral shape along the axial direction of the rotating shaft. A rotating electric machine having a magnetic bearing characterized by a magnetic bearing. 5. In claim 1, the magnetic body is constituted by a magnetic body of each magnetic bearing for radial movement, and the magnetic force part is constituted by a magnetic force part of each magnetic bearing for radial movement. A rotating electric machine having a magnetic bearing characterized by: 6. In claim 1, the magnetic body is constituted by a rotor of a motor, the magnetic force part is constituted by a stator of a motor, and the stator and rotor are relatively shifted in the axial direction. A rotating electrical machine with a magnetic bearing characterized by: