JPH0830496B2 - Magnetic bearing - Google Patents

Description

TECHNICAL FIELD The present invention relates to a radial type magnetic bearing, and particularly to ON-OF.
The present invention relates to a magnetic bearing suitable for implementing F control.

[Conventional technology]

As shown in Figure 4 on page 157, “New technology of magnetic materials and magnetic materials”, published by Soft Giken Publishing Co. in October 1981, the conventional device has four directions. In order to obtain the attraction force of, a total of 8 magnetic poles, 2 for each direction
It had magnetic poles.

Further, in JP-A-59-83829, JP-A-59-99118, and JP-A-59-151619, the excitation of one of the opposing electromagnets is weakened and the excitation of the other is weakened with respect to the displacement of the rotary shaft. There is disclosed a magnetic bearing that controls to strengthen the magnetic field.

[Problems to be solved by the invention]

However, the above-mentioned conventional device requires twice as many magnetic poles as in the attraction direction, and also has a large outer diameter in order to secure a space for accommodating a large number of exciting coils, becomes longer in the axial direction, and has a further manufacturing cost. There was a problem that the small diameter could not be made too small.

Further, the ones disclosed in JP-A-59-83829, JP-A-59-99118, and JP-A-59-151619 are provided with a magnetic pole twice in the suction direction as in the above, and a rotary shaft is provided. Is controlled, and has the same problems as those described above.

An object of the present invention is to provide a magnetic bearing in which the number of directions of attraction that can be applied to a shaft can be made equal to or more than the number of magnetic poles, and the controllability of shaft displacement is improved.

[Means for solving problems]

In order to achieve the above object, in a magnetic bearing in which an even number of magnetic poles of 4 or more having an excitation coil are arranged around an axis, each magnetic pole is formed on a common fixed iron core, and
Two magnetic poles or shafts which are energized to the exciting coil so that the magnetic poles on the respective end faces of the magnetic poles are adjacent to each other and different from the N pole and the S pole, and which are located on both sides in the direction of attracting the shaft. Of the three magnetic poles, that is, the magnetic pole closest to the direction of attracting the magnetic pole and the two magnetic poles adjacent to the magnetic pole, are independently energized to independently control the respective magnetic poles, and the magnetic pole direction and the magnetic pole are controlled. The direction is controlled in one direction.

[Action]

By changing the combination of the exciting coils of the adjacent magnetic poles, more moving directions of the shaft than the number of magnetic poles can be obtained. Therefore, the time required to move to the center is shortened.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to FIG.

In the embodiment shown in FIG. 1, the shaft 2, the fixed iron core 3, the magnetic poles 4a, 4b, 4c, 4d protruding from the fixed iron core 3 toward the shaft 2 and the magnetic poles 4a, 4b, 4c, 4d are respectively wound. Excited coils 6a, 6b, 6c, 6d
The main body of the magnetic bearing 1 is composed of. An X-axis position sensor 11 arranged on the X-axis passing through the center O of the fixed iron core 3 and a Y-axis position sensor 12 arranged on the Y-axis passing through the center O of the fixed iron core 3 and perpendicular to the X-axis. The exciting coils 6a, 6b, 6c, 6d
High-speed relays 22a, 22b, 22c, 22d that turn on and off the power to each
A control system for the magnetic bearing 1 is composed of a control unit 13 which receives signals from the position sensors 11 and 12 and performs calculations and judgments to send signals to the high speed relays 22a, 22b, 22c and 22d. The power supply 21 supplies power to the exciting coils 6a, 6b, 6c, 6d.

Next, the operation of this embodiment will be described. The center of the fixed iron core 3 is O, the area O on the + X side formed by the center O of the fixed iron core 3 and the center lines of the magnetic poles 4d and 4a is I, and the center O of the fixed iron core 3 is
And the area on the + Y side formed by the center lines of the magnetic poles 4a and 4b is I
I, a region on the -X side formed by the center O of the fixed iron core 3 and the center lines of the magnetic poles 4b and 4d is III, and is formed by the center O of the fixed iron core 3 and the center lines of the magnetic poles 4c and 4d. Let the area be IV. When a current is passed through the exciting coil 6a, the polarity of the end face of the magnetic pole 4a becomes N.
Pole, when a current is passed through the exciting coil 6b, the polarity of the end surface of the magnetic pole 4b is S pole, and when a current is passed through the exciting coil 6c, the polarity of the end surface of the magnetic pole 4c is N pole, and a current is passed through the exciting coil 6d. And the electrode
The polarity of the end face of 4d is the S pole, and the exciting coils are arranged so that the polarities of all adjacent magnetic poles are different. The position of the shaft 2 is measured by the position sensors 11 and 12, the determined value is arithmetically processed by the control unit 13, and the control unit 13 determines that the center O ′ of the shaft 2 is in the region III. Then, the exciting coils 6d and 6a of the magnetic poles 4d and 4a that constitute a region I symmetrical with the region III and the center O of the fixed iron core 3 are formed.
Turn on the high-speed relays 22d and 22a so that only the power is turned on.
Then, a signal for turning off the high speed relays 22b and 22c is output from the control 13. The high-speed relay 22 is driven by the signal output from the control unit 13.
Only d and 22a are turned on, and the exciting coil 6
A current flows through d, 6a, and the magnetic poles 4d, 4a are magnetized by the current flowing through the exciting coils 6d, 6a, and a magnetic flux passes. The magnetic flux exiting the magnetic pole 4a passes through the shaft 2, the magnetic pole 4d, and the fixed iron core 3 and the magnetic pole 4a.
Then, an attractive force is generated in the magnetic pole 4a and the shaft 2, and in the magnetic pole 4d and the shaft 2, and the shaft 2 moves in the + X axis direction due to the resultant force of the attractive forces of the two. The center O ′ of the shaft 2 approaches the center O of the fixed iron core 3 by repeating at high speed from the reception of the signals from the position sensors 11 and 12 to the movement of the shaft 2 by the suction force.

It should be noted that all the electrode stones 5a, 5b, 5c, 5d are not operated in the immediate vicinity of the center O of the fixed iron core 3, that is, all the high speed relays 22
The above operation is not hindered even if a region where a, 22b, 22c and 22d are turned off is provided. Further, although the power source 21 is shown as a constant power source in the present embodiment, the above operation is not hindered even if it is a variable power source which changes depending on the distance between the center O of the fixed iron core 3 and the center O'of the shaft 2, and the power source is not impaired. The other side of 21 is not grounded 23, but grounded 23, 23a, 23
Even if b, 23c, and 23d are common and have a constant potential, the above operation is not hindered.

FIG. 2 shows an example of the movement of O'when the center O'of the shaft 2 is on the -Y side of the region III. O 'All start of are separated by [delta] ₁ from the center O of the fixed iron core 3, the solid line O _1' starting point on the -X axis, starting point of one point chain O ₂ 'from the -X side to the -Y side 22.5 45 ° away, the starting point of the broken line O ₃ ′ is from −X side to −Y side 45
I.e., on the boundary between Region III and Region IV, O ₁ ′, O ₂ ′,
It is an example of the movement until O ₃ ′ reaches within δ ₀ , which is very close to O. The black circles in the figure are measurement points.

Table 1 below shows the position of O ₂ ′ shown in FIG. ₂ , the ON / OFF states of the high speed relays 22a, 22b, 22c and 22d and the suction direction of the shaft 2. When the center O'of the shaft is in the region III, the high speed relays 22a and 22d are turned on and the shaft is attracted to the + X side. When the center O'of the shaft is in the region IV, the high speed relays 22a and 22b are turned on. It can be seen that the shaft is attracted to the + Y side.

According to this embodiment, there are the following effects.

When the shaft has four directions of attraction, the number of magnetic poles is half that of the conventional four, which is the same as the direction of attraction, and the total area of the magnetic pole ends of the female ball that obtains the same attractive force is as small as about 65% of the conventional type. The volume of the fixed core side including the space for the excitation coil is about 70% of the conventional type, which is more compact than the conventional type.

Since the fixed iron core is common, it is not necessary to align the magnetic poles with each other.

Since the outer circumference of the fixed core is cylindrical, the housing can be easily manufactured and assembled.

Since the exciting coil wound around the magnetic pole can be manufactured separately from the fixed iron core, the productivity is good.

The number of manufactured excitation coils is half that of the conventional type, and the number of turns per location is only about 10% greater than that of the conventional type, which is resource saving.

In the embodiment shown in FIG. 3, the shaft 1, the fixed iron core 2, the magnetic poles 4a, 4b, 4c, 4d protruding from the fixed iron core 2 toward the shaft 2 and the magnetic poles 4a, 4b, 4c, 4d are respectively wound. Excited coils 6a, 6b, 6c, 6d
The main body of the magnetic bearing 1 is composed of. An X direction position sensor 11 arranged on the X axis passing through the center O of the fixed iron core 3 and a Y direction position sensor 12 arranged on the Y axis passing through the center O of the fixed iron core 3 and perpendicular to the X axis. The exciting coils 6a, 6b, 6
High-speed relay 22a I, 22a that turns on and off power to each of c and 6d
II, 22b I, 22b II, 22c I, 22c II, 22d I, 22d II and high-speed relays 22a I, 22a II, 22b I, 22b II , 22c I, 22c II, 22d
A control system for the magnetic bearing 1 is composed of a control unit 13 for sending signals to I and 22d II. The exciting coils 6a, 6b, 6
Power is supplied to c and 6d by power supplies 21I and 21II.

Next, the operation of this embodiment will be described. The center of the fixed iron core 3 is O, and the region formed by the line connecting the + X side and the middle of the magnetic pole 4d and the center O and the line connecting the middle of the + X side and the magnetic pole 4a and the center O is I , A region formed by a line connecting the center O with the middle of the magnetic pole 4a and the + X side and the center O, and a region formed with a line connecting the center of the magnetic pole 4a and the + Y axis and the center O is II, and the middle of the + Y axis and the magnetic pole 4a. And a region formed by the line connecting the center O, the + Y axis, the middle of the magnetic pole 4b and the line connecting the center O is III, and the magnetic pole 4b is +
A region formed by a line connecting the middle of the Y axis and the center O, the magnetic pole 4b, and a line connecting the middle of the -X axis and the center O is IV, -X.
The region formed by the line connecting the axis and the middle of the magnetic pole 4b and the center O and the line connecting the middle of the -X axis and the magnetic pole 4c and the center O is V, and the region between the magnetic pole 4c and the -X axis. And VI to the region formed by the line connecting the center O with the value pole 4c and the middle of the -Y axis and the center O, and connecting the center O with the middle of the -Y axis and the magnetic pole 4c. VII is a region formed by a line connecting the center O with the center line O and the center line O of the magnetic pole 4d and the Y-axis and the magnetic pole 4d, and the magnetic pole 4d with a line connecting the center O of the magnetic pole 4d and the center of the Y-axis. A region VIII formed by a line connecting the center of the + X axis and the center O is defined as the region VIII, and the center of the axis 2 is defined as O ′. When a current is passed through the exciting coil 6a, the polarity of the end face of the magnetic pole 4a is N pole, and a current is passed through the exciting coil 6b.
The polarity of the end face of 4b is S pole, the polarity of the end face of the magnetic pole 4c is N pole when a current is passed through the exciting coil 6c, and the polarity of the end face of the magnetic pole 4d is S pole when a current is passed through the exciting coil 6d. The exciting coils are arranged so that the polarities of the magnetic poles adjacent to each other are different. The potentials of the power supply 22II and the power supply 22I are set so that the magnetic flux passing through the magnetic poles when the power supply 22II is energized to the excitation coil is twice the magnetic flux passing through the magnetic poles when the power supply 22I is energized to the same excitation coil. ing. The high speed relays 22a I and 22a II, 22b I and 22b I
I, 22c I and 22c II, 22d I and 22d II are considered so as not to be turned on at the same time. The position of the shaft 2 is measured by the position sensors 11 and 12, and the measured value is used by the control unit 13
As a result of the calculation processing in step S1, the control unit 13 determines that the center O'of the shaft 2 is in the region VI, and the shaft 2 is moved in the direction of the region II symmetrical with the region VI and the center O of the fixed iron core 3. The high-speed relay 22aII is turned on so as to energize the exciting coil 6a of the magnetic pole 4a with the high-potential power source 21II so that the exciting coil 6a of each of the magnetic poles 4d and 4b has a low voltage. The high-speed relays 22d I and 22b I are turned on so as to energize the power source 21I of potential, and the other high-speed relays 22a I, 22c I, 22b II, 22c II, 22d II and 22d II are turned on.
The control section 13 outputs a signal for FF. Only the high-speed relays 22d I, 22a II, 22b I are turned on by the signal output from the control unit 13.
In the state, a current flows from the power source 21II to the exciting coil 6a, the magnetic pole 4a is magnetized, and a magnetic flux passes through the magnetic pole 4a.
A current flows from the power source 21I to the exciting coils 6d and 6b and the magnetic pole 4
The d and 4b are magnetized and the magnetic flux passes through the magnetic poles 4d and 4b. The magnetic flux exiting the magnetic pole 4a reaches the sleeve 2'made of a magnetic material attached to the shaft 2 through the air gap and is divided into two parts. One of the separated magnetic fluxes is about clockwise in the sleeve.
It makes a quarter turn and passes through the air gap to reach the magnetic pole 4d. The other split magnetic flux makes 1/4 turn in the counterclockwise direction in the sleeve and reaches the magnetic pole 4b through the air gap. The magnetic pole 4d
The magnetic flux emitted from the fixed iron core 3 to the fixed iron core 3 by 1/4 turns counterclockwise around the fixed iron core 2, and the magnetic flux emitted from the magnetic pole 4b to the fixed iron core 2 makes 1/4 turn clockwise around the fixed iron core 3. And merges with the magnetic pole emerging from the magnetic pole 4d and returns to the magnetic pole 4a. When the magnetic flux flows as described above, an attractive force is generated on the magnetic pole 4a and the shaft 2, the magnetic pole 4d and the shaft 2, and the magnetic pole 4b and the shaft 2.
The attraction force generated on the magnetic pole 4b and the attraction force generated on the magnetic pole 4b and the shaft 2 have almost the same magnitude and opposite directions, so that they cancel each other out, so only the attraction force generated on the magnetic pole 4a and the shaft 2 acts greatly. Then, the shaft 2 moves in the direction of the magnetic pole 4a.
If the magnetic poles 4b and 4d are not excited, the magnetic flux from the magnetic pole 4a reaches the magnetic pole 4c via the shaft 2, passes through the fixed iron core 3, and returns to the magnetic pole 4a. In this case, shaft 2 has magnetic pole 4c
Is attracted to the side of the magnetic pole 4c in the direction opposite to the center. Excitation of the magnetic poles 4b and 4d causes the magnetic flux from the shaft 2 to pass through the magnetic pole 4c.
This is to prevent it from reaching as much as possible. The center O ′ of the shaft 2 approaches the center O of the fixed iron core 2 by repeating the operation from the signal reception of the position sensors 11 and 12 to the movement of the shaft 2 by the suction force at high speed.

It should be noted that all the electromagnets 5a, 5b, 5c, 5d are not operated in the vicinity of the center O of the fixed iron core 2, that is, all the high speed relays 22a.
I, 22a II, 22b I, 22b II, 22c I, 22c II, 22d I, 22d II
Even if a region to be turned off is provided, the above operation is not hindered. Furthermore, although the power supplies 21I and 21II are shown as constant currents in this embodiment,
These do not hinder the above operation even as a variable power source that varies depending on the distance between the center O of the fixed iron core 2 and the center O'of the shaft 2, and the other of the power sources 21I and 21II is not grounded 23, but grounded 2
The above operation is not hindered even if 3,23a, 23b, 23c, and 23d are common and have a constant potential. In this embodiment, the sleeve 2'made of a magnetic material is inserted into the shaft 2, but at least the entire shaft 2 portion included in the region that acts as a magnetic bearing may be made of a magnetic material, and the sleeve 2'and the fixed iron core 2 may be used. Does not have to be a single entity.

In FIG. 4, an example of the motion of 'said center O when is on the -Y side area V' center of the shaft 2 O 'as, of the shaft 2 center O' O ₁ is a region VI -Y Let O ₂ ′ be an example of the movement of the center O ′ when it is on the side, and O ₁ ′ and O ₂ ′ are the center O of the fixed iron core 2.
Only from [delta] _1, [delta] from the center O of the fixed iron core 2 from position ₁
Only the movement from the position until reaching the very close δ ₀ of the center O of the fixed iron core 3 is shown. Black circles in the figure are position sensors
These are the points measured by 11,12.

Table 2 shows the position of the center O ₁ ′ of the shaft 2 shown in FIG. 4 and the high speed relays 22a I, 22a II, 22b I, 22b II, 22c I, 22c II, 22d.
The ON-OFF state of I and 22d II and the suction direction of the shaft are shown. In the suction direction of the axis, (+ X, + Y) indicates that it moves in a direction inclined by 45 ° from the + X axis to the + Y axis. When the center O ₁ ′ of the shaft 2 is in the region V, only the high speed relays 22d I and 22a I are turned on to suck the shaft toward the + X side, and when the center O ′ of the shaft is in the region VI, the high speed relay 22a II It can be seen that only 22d I and 22b I are turned on and the axis is attracted to the (+ X, + Y) side.

According to the present embodiment, when the suction direction of the shaft is 8 directions,
The number of magnetic poles is four, which is half of the direction of attraction, which is 1/4 of that of the conventional type. The total area of the magnetic pole ends to obtain the same attractive force is 50% or less of that of the conventional type, and the exciting coil storage space is also small. The volume of the fixed iron core side including it is about 50% of the conventional type, which is more compact than the conventional type, and the shaft can be attracted in the direction of twice the number of magnetic poles. It changes 90 ° in the direction of 4 magnetic poles, but only needs to change 45 ° in the direction of 4 magnetic poles, which makes the movement smoother. Since the fixed iron core is common, there is no need to align the magnetic poles with each other. Since the outer circumference is circular, the housing is easy to assemble and easy to assemble. The exciting coil wound around the magnetic pole can be manufactured separately from the fixed iron core, resulting in good productivity.
The number of manufactured excitation coils is half that of the conventional type, and the number of turns per coil is only about 30% higher than the conventional type, which is resource saving.
There is an effect.

FIG. 5 shows another embodiment, and the same parts as those in FIG.

The present embodiment differs from the embodiment shown in FIG. 3 in the configuration, that a power source 21I having a positive potential and a power source 21I having a negative potential are used as power sources.
A high-speed relay 22a I, 22b I, 22c I, 22d that has two of II and turns on and off the power supply 22I having the positive potential as a high-speed relay.
I and the power supply 21III having the negative potential and the earth 23a, 23b, 23c, 23
High-speed relay 22a III, 22b III, 22c III, 22d for switching d
III.

Since the operation of this embodiment is almost the same as the operation of the embodiment shown in FIG. 3, only the operation of the high speed relay will be described and the others will be omitted.

When the center O'of the shaft 2 is in the area VI, 22d I, 22a I, 22b I of the high speed relay on the power source 21I side having the positive potential are turned on.
N, the remaining 22c I is turned off, and the power supply 21III with the negative potential
Switch to the power supply side of 22a III among the high speed relays on the side, and leave the remaining 22b III, 22c III, 22d III on the ground side to attract to the area II side of the shaft 2 and to the center of the shaft 2. It operates so that O ′ is brought closer to the center O side of the fixed iron core 3.

It should be noted that all the electromagnets 5a, 5b, 5c, 5d are not operated in the immediate vicinity of the center O of the fixed iron core 3, that is, all the high-speed relays 22a I, 22b I, 22c I, having a positive potential on the side of the power source 21I, 22d I OF
The above operation is not hindered even if the area F is provided. Further, although the power supplies 21I and 21III are shown as constant power supplies in this embodiment,
Even if these are variable power sources that are changed by the distance between the center O of the fixed iron core 3 and the center O ′ of the shaft 2, they do not hinder the above operation. Further, there is no problem even if the power source 21III side having a negative potential is turned on and off and the power source 21I side having a positive potential is switched and used.

The position of the center O ₂ ′ of the shaft 2 shown in FIG. 4 and the high speed relays 22a I, 22b I, 22c I, 22d I, 22a III, 22b III, 22c are shown in Table 3.
The state of III, 22d III and the suction direction of the shaft 2 are shown. In the suction direction of the axis, (+ X, + Y) indicates that the axis moves from the + X axis toward the + Y axis by 45 °. The center O ₂ ′ of the axis is the region
In VI, among the high-speed relays on the power supply 21I side with positive potential, 22d I, 22a I, 22b I are turned on, and only the high-speed relay 22a III on the power supply 21III side with negative potential is turned on. Switch to suction the shaft 2 to the (+ X, + Y) side, and center the shaft 2
When O ₂ ′ is in region VII, only the high speed relays 22a I and 22b I of the power supply 21 side with positive potential are turned on and all the high speed relays of power supply 21 III with negative potential are switched to the ground side. It can be seen that the cage shaft is attracted to the + Y side.

According to this embodiment, in addition to the effects of the embodiment of FIG. 3, high speed relays 22a I and 22a III, 22b I and 22b III, 22c I and 22c II are provided.
I, 22d I and 22d III can be operated at the same time, and there is an effect that a response can be made at a higher speed as compared with the embodiment of FIG.

As described above, according to each embodiment of the present invention, since the number of magnetic poles may be half the number in the suction direction of the shaft, the total magnetic pole end area can be reduced to 45 to 50% as compared with the conventional type, and the magnetic poles can be reduced. Since the total occupied volume of the exciting coil wound around the coil can be reduced to about 50% compared to the conventional type, the axial length is shortened and the radial length of the magnetic pole is shortened, that is, the outer diameter is reduced, resulting in a compact magnetic bearing. Also, it has the effect of providing a magnetic bearing that is as small as about 2/3 of the conventional type with a minimum shaft diameter of the armature.

〔The invention's effect〕

As described above, according to the present invention, the magnetic pole closest to the direction in which the shaft is attracted and each exciting coil of at least one of the two magnetic poles adjacent to the magnetic pole are independently energized, and each magnetic pole is Since they can be controlled independently, the combination of exciting coils can be changed, and the suction direction of the shaft can be set to 3
When three magnetic poles having an exciting coil are arranged in more than one direction, the maximum number of directions can be six, and the number of magnetic poles can be more than one. As a result, the suction control direction is increased, and the shaft can be moved to the center of the fixed iron core at a higher speed.

[Brief description of drawings]

FIG. 1 is a control system diagram of a cross section perpendicular to the axis of the magnetic bearing of the present invention, FIG. 2 is an explanatory view showing the movement of the shaft center O ′, and FIG. 3 is a shaft of another embodiment of the magnetic bearing of the present invention. FIG. 4 is a control system diagram showing a movement of the shaft center O ′, and FIG. 5 is a control system diagram showing a cross section perpendicular to the axis of another embodiment of the present invention. 2 ... Axis, 3 ... Fixed core, 4a, 4b, 4c, 4d ... Magnetic pole, 6a,
6b, 6c, 6d …… Excitation coil, 11 …… X axis position sensor, 12…
… Y-axis position sensor, 13 …… Control unit, 21I, 21II, 21III ……
Power supply, 22a I, 22b I, 22c I, 22d I, 22a II, 22b II, 22c I
I, 22d II, 22a III, 22b III, 22c III, 22d III …… High speed relay, 23,23a, 23b, 23c, 23d …… Ground.

Claims (1)

[Claims] 1. In a magnetic bearing in which an even number of magnetic poles of 4 or more having an excitation coil are arranged around an axis, each magnetic pole is formed on a common fixed iron core, and magnetic poles on respective end faces of the magnetic poles are adjacent to each other. The exciting coil is energized so as to be different from the N pole and the S pole when they match each other, and the two magnetic poles located on both sides in the direction of attracting the shaft or the magnetic pole closest to the direction of attracting the shaft and this magnetic pole. The two magnetic poles adjacent to the two magnetic poles and the three magnetic poles are independently energized to independently control the respective magnetic poles, and the magnetic poles are controlled in one direction between the magnetic poles and one direction. Magnetic bearings.