JPH0565919A - Passive magnetic bearing device - Google Patents

Abstract

PURPOSE:To dispense with control of entire five degrees of freedom by moving flanges by relative force acting between the flanges and fixed coils disposed between the flanges so as to nullify horizontal displacement generated by unstable force. CONSTITUTION:A horizontally unstable force supporting means is fixed to a rotating part 14, and includes at least a pair of mutually opposed flanges 22, 24. On the respective opposed faces of these flanges 22, 24, plural permanent magnets 26, 28 are disposed in circumferential rows. The polarity of these permanent magnets 26, 28 is so set that the magnetic poles of the mutually adjacent magnets are unlike, and plural permanent magnets 26, 28 disposed in rows are connected by magnetic material. The opposed permanent magnets 26, 28 are disposed with mutually unlike magnetic poles so as to attract each other. Numerous coils fixed in relation to a fixed part 12 are disposed between the opposed flanges 22, 24. The entire position control in five degrees of freedom is thereby performed by a passive magnetic bearing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bearing device for supporting a rotating portion in a non-contact state with a fixed portion, and in particular,
The present invention relates to a passive magnetic bearing device in which the magnetism generating means is a permanent magnet.

[0002]

2. Description of the Related Art A request for supporting a rotating member (rotating portion) in a non-contact state is carried out in a vacuum environment such as in a field requiring a very clean environment such as semiconductor equipment or space technology. Exist in other fields. In order to meet the demand, various magnetic bearings have been proposed that use the attractive force or repulsive force (magnetic force) of an electromagnet or a permanent magnet.

In this case, in order to eliminate the unstable force generated in the rotating portion, an active magnetic bearing using an electromagnet is often used so that the magnetic force can be adjusted easily and accurately.
A so-called 5-axis control type magnetic bearing device has been proposed in which position control in all five degrees of freedom other than the rotation axis is performed by an active magnetic bearing.

[0004]

However, in the case of an active magnetic bearing using an electromagnet, it is necessary to supply an electric current in order to generate a magnetic force, and the amount of energy consumption is large correspondingly, resulting in energy saving. There is a problem that it goes against the request.

Further, the control by the active magnetic bearing requires complicated processing such as position detection of the rotating portion and calculation of the current to be supplied, so that the structure becomes complicated and the manufacturing cost of the active magnetic bearing increases. There is also the problem of the reliability of the circuit for active control and the power failure countermeasure of commercial power.

Further, in a vacuum environment such as outer space, heat resulting from the supplied current is accumulated, which causes malfunction of the device itself.

On the other hand, a passive magnetic bearing using a permanent magnet which does not require the supply of electric current has been proposed. However, in the case of permanent magnets, it is difficult to control the magnetic force, so
It has not been possible with the conventional technology to perform position control in all five degrees of freedom other than the rotation axis by using a passive magnetic bearing.

Therefore, a magnetic bearing device has been proposed in which a passive magnetic bearing is used to support some of the above five degrees of freedom, and an active magnetic bearing is used for the rest. If configured in this way, the power consumption will certainly be reduced. However, the above problems cannot be completely solved. Particularly in space technology and high vacuum technology, there is an eager need for a bearing that realizes non-contact state by magnetism without consuming electric power and realizes high reliability.

The present invention has been proposed in view of the above-mentioned problems of the prior art. When the number of rotations exceeds a certain value, position control in all five degrees of freedom other than the rotation axis is performed by the passive magnetic bearing. The purpose is to provide a passive magnetic bearing device that can be used.

[0010]

The passive magnetic bearing device of the present invention supports a horizontal instability force in a passive magnetic bearing device which supports a rotating portion in a non-contact state with a fixed portion. The means includes at least one pair of two flanges fixed to the rotating part and facing each other,
A plurality of permanent magnets are arranged in a row in the circumferential direction on each of the facing surfaces of the pair of flanges, and the polarities of the permanent magnets are set so that the magnetic poles of adjacent ones are different from each other. The plurality of permanent magnets arranged at are connected at their ends by a magnetic material, and the facing permanent magnets are arranged so that they attract each other with different magnetic poles. A large number of windings fixed with respect to are arranged.

The passive magnetic bearing device of the present invention is a passive magnetic bearing device which supports a rotating part in a non-contact state with a fixed part, wherein the means for supporting an unstable force in the horizontal direction is a rotating part. At least one pair of two flanges fixed to the section and facing each other is included, and a plurality of permanent magnets are arranged in a row in the circumferential direction on one of the facing surfaces of the pair of flanges. The permanent magnets are arranged such that their polarities are set so that the magnetic poles of the adjacent magnets are different from each other, and the ends of the plurality of permanent magnets arranged in a row are connected by a magnetic material, and A magnetic material is provided in a portion of the facing surface facing the permanent magnet, and a large number of windings fixed to the fixing portion are arranged between the facing flanges.

Further, the passive magnetic bearing device of the present invention is
In the passive magnetic bearing device that supports the rotating portion in a non-contact state with the fixed portion, the means for supporting the instability in the horizontal direction is composed of two flanges fixed to the rotating portion and facing each other. At least one pair is included, and a plurality of permanent magnets are arranged in a row in the circumferential direction on the pair of flanges, and a part of a portion of one flange on the side of the other flange that faces the permanent magnets is disposed. Has a magnetic material portion, and a large number of windings fixed to the fixing portion are arranged between the opposing flanges.

In the practice of the present invention, the magnetic material is preferably iron.

Here, when the plurality of permanent magnets arranged in a row in the circumferential direction of the facing surface of the flange are arranged in one row, each of the plurality of windings has a plan shape in the center. It is preferable that the portions are insulated and crossed to form an approximately eight-character shape. On the other hand, when the plurality of permanent magnets arranged in rows in the circumferential direction of the facing surface of the flange are arranged in two rows, each of the plurality of windings has a hexagonal planar shape. Is preferred.

The pitch of each of the plurality of windings is
It is preferably 65 to 95% of the circumferential pitch of the permanent magnet. If the pitch of the windings is too small, the electrical resistance decreases, and the current flowing through the windings described later increases, but the holding force is too short to obtain sufficient force. On the other hand, if the pitch of the winding is too large, the portion that becomes the holding force becomes sufficiently long, but the electric resistance increases and the current decreases, so that a sufficient force cannot be obtained.

Further, in addition to the plurality of windings, a winding for passing a current in a direction transverse to the magnetic fields of the plurality of permanent magnets by rotation to generate a rotational force is arranged between the flanges, and is a passive type. It is preferable that the magnetic bearing device also acts as a motor. In this case, a sensor that detects the relative rotation angle between the rotating part and the winding and a power supply that supplies the current to the winding are changed to change the direction of the current flowing through the winding based on the output of the sensor. It is preferable to provide switching means and.

Alternatively, in the case where the planar shape of each of the plurality of windings has a substantially eight-character shape in which the central portion is insulated and crosses, the plurality of windings having the eight-character shape are It is preferable that at least a part of the conductor is connected by a conductor, and the conductor is connected to an external power source in such a manner that a current flows through the conductor to generate a rotational force. In this case, when the flange rotates and the 8-shaped winding crosses the adjacent permanent magnets having different polarities, the fact is detected by a rotation position sensor or the like, and the power supply switching means connects the windings. It is preferable to switch the power source connected to the power source to a power source having a different current direction so that the rotational force is maintained.

Here, the permanent magnet may be fixed. For such a configuration, it is preferable that the flange serves as a fixed portion and the large number of windings arranged between the flanges serve as a rotating portion.

It is preferable to provide a contact type bearing such as a ball bearing in order to perform horizontal support when the rotating part is stopped or rotating at a very low speed.

[0020]

Next, the operation of the present invention will be described.

Passive magnetic bearings are commonly used to support thrust acting vertically or vertically. If the vertical direction is supported by a passive magnetic bearing, an unstable force is generated in the horizontal direction. On the other hand, according to the present invention, the relative force acting between the flange and the fixed winding arranged therebetween moves the flange to cancel the horizontal displacement caused by the unstable force. -ing

The polarity of the permanent magnets arranged on the flange is
The polarities of the adjacent permanent magnets and the polarities of the opposing permanent magnets (arranged on the flange) are different. The permanent magnet is magnetically connected to the adjacent permanent magnet via a magnetic material. Therefore, one permanent magnet, for example, the permanent magnet M in FIG. 3, faces the adjacent magnet, the flange-side magnet facing the adjacent magnet, and the magnet adjacent to the facing magnet, that is, the permanent magnet M. With a magnet,
Form a magnetic path. However, it is also possible to form the magnetic path by the permanent magnets M, the adjacent magnets, and the magnetic material on the opposing flange side.

Next, the fixed winding C arranged between the flanges
However, as shown in FIG. 3, consider the case where it is located on the permanent magnet M. There is no unstable force in the horizontal direction H,
If there is no change in the relative position between the rotating portion and the fixed portion, the relative position between the flange and the fixed winding C does not change. When the unstable force does not exist, the center line C _c of the fixed winding C
Passes through the center of the permanent magnet M as shown by the solid line in FIG.
Then, each time the fixed winding C crosses the magnetic path formed by the magnet M (existing in the direction perpendicular to the paper surface of FIG. 3 from the magnet M),
Induced electromotive forces E1 and E2 are generated in the portions C1 and C2 of the fixed winding C, respectively. Here, since the areas of the portions C1 and C2 that cross the magnetic path are equal, the induced electromotive forces E1 and E2 that are generated are also equal, and both are in the central portion C.
_No current flows through the fixed winding C because they form one loop in _c and cancel each other out. Therefore, since a relative force does not act between the fixed winding C and the flange, the resistance force of the rotational movement does not occur.

However, if there is an unstable force in the horizontal direction H and the relative position between the rotating portion and the fixed portion changes, the relative position between the flange and the fixed winding C also changes, and the fixed winding C The relative position between the permanent magnet M and the permanent magnet M is shown by a dotted line in FIG. 3, for example. As a result, the areas of the portions C1 and C2 that cross the magnetic path are not equal, and the induced electromotive forces E1 and E2 that are generated are also not equal, so that a current flows through the entire fixed winding C. Then, the flange rotates together with the rotating portion, and the fixed winding C relatively crosses the magnetic path of the permanent magnet M, so that a force as indicated by an arrow A acts on the fixed winding C. Since this force (arrow A) is a relative force between the flange and the fixed winding C, a force in the direction opposite to the arrow A acts on the flange, and thus an unstable force in the horizontal direction H. Is eliminated.

A force (hereinafter, referred to as "holding force": a force indicated by an arrow A in FIG. 3) A for eliminating this unstable force is generated when the winding C crosses the magnetic path of the permanent magnet M. Therefore, this holding force A is generated only when the flange rotates.

As described above, according to the present invention, the unstable force is eliminated in the horizontal direction H without providing an electromagnet.
All the above-mentioned problems are solved.

Here, the larger the number of fixed windings arranged between the flanges, the stronger the force for eliminating the unstable force. On the other hand, when the distance between the flanges is widened, the magnetic flux density flowing in the magnetic path is reduced and the holding force is weakened. Therefore, it is preferable to increase the number of windings without widening the distance between the flanges. In other words, it is desirable to improve the volume occupancy of the winding between the flanges. In the present invention, the volume occupancy rate can be increased by making the plane shape of the winding wire into an approximately 8-shape or a hexagonal shape.

Further, in addition to the winding for generating a holding force like the fixed winding C shown in FIG. 3, a winding to which an electric current is externally supplied in order to generate a rotating torque in the flange and the rotating portion. If the magnetic path existing between the flanges is crossed, the passive magnetic bearing can function as a motor.

[0029]

EXAMPLES Examples of the present invention will be described below.

1 and 2 show an embodiment of the most basic structure of the present invention. In FIG. 1, a passive magnetic bearing device indicated by reference numeral 10 as a whole has a fixed portion 12 and a rotating portion 14, and a permanent magnet 16 of the fixed portion 14 and a permanent magnet 18 of the rotating portion 14 face each other. Have the same polarity and are arranged so that repulsive force acts. The rotating shaft 20 is fixed to the rotating portion 14, and the flange 2 is attached to the rotating shaft 20.
2, 24 are fixed.

A plurality of permanent magnets 26, 28, ... Are respectively arranged on the flanges 22, 24 in a line in the circumferential direction as shown in FIG. These permanent magnets 26, 28, ...
Are arranged such that the magnets facing each other have different polarities as shown in FIG. 1, and the magnets adjacent to each other have different polarities as shown in FIG. The end of the permanent magnets 26 on the side opposite to the flange 24 (lower side in FIG. 1) is made of the iron member 3
0 (yoke), and the end of the permanent magnet 28 on the side opposite to the flange 22 (upper side in FIG. 1) is connected to the iron member 32 (yoke). The permanent magnet 26 described above
, 28 ... Polarity setting, and members 30, 3 made of iron
2, the adjacent permanent magnets 26 and the opposing permanent magnets 28 form magnetic paths .PHI ...., which are shown by the one-dot chain line in FIG.

Between the flanges 22 and 24, in other words, a large number of windings 34 are arranged so as to traverse the magnetic paths Φ. Here, the individual windings 34 are insulated from each other, and a large number of them are fixed and fixed to the fixing portion 12. As described above, the larger the number of the windings 34 is, the more preferable it is. However, in FIG. 1, only seven windings are shown for simplification.

Although not shown in FIG. 1, a motor for driving the rotating portion 14 and the rotating shaft 20 is provided. And the thrust in the axial or vertical direction V is
It is supported by the repulsive force of the permanent magnets 16 and 18. However, when the repulsive force between the permanent magnets 16 and 18 acts,
An unstable force occurs in the horizontal direction H. If an unstable force is generated in the horizontal direction H, the relative positions of the flanges 22 and 24 and the windings 34 in the horizontal direction H are also changed.

When the rotating portion 14 is stopped, it is horizontally supported by a contact bearing (not shown). Then, the rotating portion 14 is rotated by a motor (not shown), and the winding 34 ...
When the magnetic field crosses the magnetic path Φ ..., the holding force A (FIG. 3) is generated as described above with reference to FIG. 3, cancels the unstable force, and passively stabilizes the position in the horizontal direction H. It is done.

FIG. 4 is a simplified view of another embodiment. In the embodiment shown in FIG. 1, the flanges 22, 24 are
, 28 ... are provided on all of the above, but in the embodiment shown in FIG. 4, the permanent magnets are provided only on one flange (flange 24 in FIG. 4) and correspond to the other flange. Members 30A made of iron are arranged in the portion. The members 30A ... Are integrated with the iron member 30 connecting the ends of the permanent magnets 26 ... In the embodiment of FIG.

Also in this embodiment, the permanent magnet 28 and the member 30 are used.
A, the member 30, the member 30A, the permanent magnet 28, and the member 32 form a magnetic path Φ. Others are the same as the embodiment of FIG.

FIG. 5 shows another embodiment. In this embodiment, the permanent magnets 26, ...
28 are arranged, but at the same time, magnetic materials 30A ... 3
2A ... are also arranged. The permanent magnets and the magnetic materials are alternately arranged on each flange.
In this embodiment, the permanent magnet 28, the member 30A, the member 3
0, the permanent magnet 26, the member 32A, and the member 32 form a magnetic path Φ. Others are the same as the embodiment of FIG.

As mentioned above, the larger the space occupied by the volume of the windings 34 in the space between the flanges 22 and 24, that is, the larger the space occupancy, the larger the holding force A (FIG. 3) and the horizontal. The directional stability function is improved. for that reason,
As schematically represented in FIGS. 2 and 3, the individual windings 34 ...
Has an approximately eight-character shape. The shape of this winding 34 ...
Is shown in. It should be noted that although circular or rectangular windings can be adopted, the volume occupancy rate is not so good.

FIG. 6 shows a state in which the winding 34-1 is just above when passing through the permanent magnet 26. Here, a holding force is generated in the crossed portions cd and hi of the winding wire 34-1. The part cd is located above the part hi. As is apparent from FIG. 6, the portion of the winding 34-1 that passes through the region of the width w of the magnet 26 is the crossed portions cd and hi and the straight portions cb, de, gh, and ij.

By constructing the winding 34 in a shape as shown in FIG. 6 and applying insulation, as shown in FIG.
It is possible to arrange 4 ... This maximizes the space occupancy.

In the embodiment shown in FIG. 1, the flanges 22 and 24 are provided with the permanent magnets 26, 28, ... In a row, but it is also possible to provide two or more rows. Figure 8
An example in which two rows of permanent magnets are provided is shown (flange 2
2, permanent magnets 26A, 26B, and only one winding are shown). And, as the shape of the winding so that the space occupancy rate is improved, an approximately hexagonal winding 50 is shown.

In FIG. 8, the winding 50 generates a holding force in the obliquely extending portions kl, mn, no and pk.
The lateral ends k and n are the permanent magnets 26A and 26B.
Does not protrude beyond the region of width w. Also, part k
l, lm, and mn are located above the parts no, op, and pk. In other words, step portions exist at the lateral ends k and n, as shown in FIG. By this step portion, the winding 50 is insulated and can be efficiently overlapped as shown in FIGS.

In FIG. 9, the pitch of the winding wire 50 is P.
is indicated by _c, the permanent magnets 26A ... and 28A ... pitch is shown at P _p. Although not explicitly shown, the pitch P _c is set to about 80% of the pitch P _p . This also applies to the winding 34 shown in FIGS.

FIG. 11 shows still another embodiment of the present invention. This embodiment has the same structure as that of the embodiment shown in FIG. 1 (however, only four permanent magnets 26 are shown for simplification), but in addition to the winding 34, a rotary torque generating member is used. A winding wire 60 is provided.

The torque generating winding 60 is connected to the power source 62 and can traverse each permanent magnet 26. In the state as shown in FIG. 11, the winding 60 has a power source 62A.
When a current flows from (indicated by an arrow in the winding wire 60), a force as indicated by an arrow M acts on a portion crossing each permanent magnet 26. If winding 60 is fixed, a force in the opposite direction of this force M causes flange 22 to rotate clockwise. Therefore, the winding 60 and the permanent magnet 26 act as a motor.

When the flange 22 rotates and crosses adjacent permanent magnets having different polarities, a rotation sensor (not shown) detects that fact and the power source 62A connected to the winding 60 is fed to the power source 62B by the power source switching means (not shown). Switch.
As a result, the force M continues to be generated.

Consider again the embodiment of FIG. When a current is passed from a to f in FIG. 6, when the vicinity of the intersection of the winding is near the magnet, the current near the intersection reacts with the magnetic flux of the magnet to generate a rotational force. In this case, of the current near the intersection, only the horizontal component of FIG. 6 contributes to the rotational force, and the vertical components cancel each other out as a force, so the rigidity in the horizontal direction of FIG. 6 is not affected. Therefore, some or all of the large number of 8-shaped windings can be used as the windings of the motor. By doing so, it is possible to generate the rotational torque by using only (a part or all of) the 8-shaped winding without the torque generating winding 60 shown in FIG. Character winding and torque generating winding 60
The configuration is simpler than the case where and are provided separately. 12 and 13 are specifics of the above contents. FIG. 12 shows an example in which a plurality of 8-shaped windings 34 ... Are connected in series, and FIG. 13 shows an example in which they are connected in parallel. There is. Further, reference numeral 64 indicates a conductor wire for connecting the windings 34 ...

Although the permanent magnet is shown on the rotating side in the illustrated embodiment, it may be on the fixed side except when it is used as a motor (FIGS. 11 to 13). In other words, if the flanges are fixed, the plurality of windings arranged between the flanges are configured as a rotating portion, and the fixing means (not shown) for fixing the flanges is included, The permanent magnet is on the fixed side. Add that fact.

[0049]

The effects of the present invention are listed below.

(1) The passive magnetic bearing can be used for stabilization in all five degrees of freedom other than the rotation axis. In other words, all five degrees of freedom can be uncontrolled.

(2) The power consumption is reduced, and the problems of heat generation and heat storage are solved.

(3) Since it is not an active type, a control electronic circuit is not required, reliability is improved, and manufacturing costs and maintenance costs are kept low.

(4) The volume occupancy of the winding can be improved and the holding force can be increased.

(5) The bearing can act as a motor.

[Brief description of drawings]

FIG. 1 is a front view showing a basic embodiment of the present invention.

FIG. 2 is a view on arrow XX in FIG.

FIG. 3 is a partially enlarged plan view illustrating the operation of the present invention.

FIG. 4 is a partial sectional view showing a main part of another embodiment of the present invention.

FIG. 5 is a partial sectional view showing a main part of another embodiment of the present invention.

FIG. 6 is a partially enlarged view showing an example of a winding wire used in the present invention.

FIG. 7 is a diagram showing a state in which the windings of FIG. 6 are stacked.

FIG. 8 is a partially enlarged plan view showing another embodiment of the present invention.

9 is a partially enlarged side view showing a state in which windings used in the embodiment of FIG. 8 are stacked.

10 is a diagram showing a state in which windings used in the embodiment of FIG. 8 are stacked.

FIG. 11 is a plan view showing still another embodiment of the present invention.

FIG. 12 is a plan view showing another embodiment of the present invention.

FIG. 13 is a plan view showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Passive type magnetic bearing device 12 ... Fixed part 14 ... Rotating part 16, 18 ... Permanent magnet (passive type axial magnetic bearing) 20 ... Rotating shaft 22, 24 ... Flange 26, 26A, 26B, 28, 28A, 28B, M ... Permanent magnet 30, 30A, 32, 32A ... Magnetic material 34, 34-1, 50, 60, C ... Winding Φ ... Magnetic path 62, 64 ... Conductor wire

Claims (9)

[Claims] 1. In a passive magnetic bearing device for supporting a rotating part in a non-contact state with a fixed part, means for supporting an unstable force in the horizontal direction are fixed to the rotating part and face each other. At least one pair of two flanges is included, and a plurality of permanent magnets are arranged in a row in the circumferential direction on each of the facing surfaces of the pair of flanges, and the permanent magnets are adjacent to each other. The polarities are set so that their magnetic poles are different, a plurality of permanent magnets arranged in a row are connected by a magnetic material, and the opposing permanent magnets are arranged so that their magnetic poles are different and attract each other. The passive magnetic bearing device is characterized in that a large number of windings fixed to a fixed portion are arranged between opposed flanges. 2. In a passive magnetic bearing device for supporting a rotating part in a non-contact state with a fixed part, means for supporting a horizontal unstable force are fixed to the rotating part and face each other. At least one pair of two flanges is included, and a plurality of permanent magnets are arranged in a row in the circumferential direction on one of the facing surfaces of the pair of flanges, and the permanent magnets are adjacent to each other. The polarities are set so that the magnetic poles of the two flanges are different from each other, and the plurality of permanent magnets arranged in a row are connected by a magnetic material, and a magnetic material is formed on a portion of the facing surface of the other flange that faces the permanent magnet. The passive magnetic bearing device is characterized in that a plurality of windings fixed to the fixed portion are arranged between the opposing flanges. 3. In a passive magnetic bearing device for supporting a rotating part in a non-contact state with a fixed part, means for supporting a horizontal unstable force are fixed to the rotating part and face each other. At least one pair of two flanges is included, and a plurality of permanent magnets are arranged in a row in the circumferential direction on the one pair of flanges. A passive magnetic bearing device, characterized in that a magnetic material portion is formed in a part of a portion, and a large number of windings fixed to a fixed portion are arranged between opposed flanges. 4. A plurality of permanent magnets arranged in a row in the circumferential direction of the facing surface of the flange are arranged in one row, and each of the plurality of windings has a plane shape of a substantially 8-shape. The passive magnetic bearing device according to any one of claims 1 to 3. 5. A plurality of permanent magnets arranged in rows in the circumferential direction of the facing surface of the flange are arranged in two rows, and each of the plurality of windings has a hexagonal planar shape. The passive magnetic bearing device according to any one of claims 1 to 3. 6. The passive magnetic bearing device according to claim 4, wherein a pitch of each of the plurality of windings is 65 to 95% of a circumferential pitch of the permanent magnet. 7. In addition to the plurality of windings, windings for passing a current in a direction transverse to the magnetic fields of the plurality of permanent magnets to generate a rotational force are arranged between the flanges. 6. The passive magnetic bearing device according to any one of 6 above. 8. The passive magnetic bearing device according to claim 4, wherein at least a part of the plurality of windings each having a planar shape of about 8 is connected by a conductor, and the conductor has a current. A passive magnetic bearing device, characterized in that the conducting wire is connected to an external power source so that a rotating force flows to generate a rotating force. 9. The passive magnetic bearing device according to claim 1, wherein the flange is a fixed portion, and the multiple windings arranged between the flanges are rotating portions. Characteristic passive magnetic bearing device.