JP2022030833A - Magnetic pole and magnetic bearing - Google Patents

Abstract

To provide a magnetic pole and a magnetic bearing capable of improving control accuracy of a position of a rotation axis.SOLUTION: A magnetic bearing 1 comprises: an actuator rotatably supporting a rotation axis 101 in a non-contact manner; and a position sensor that obtains information related to a position of the rotation axis 101. A magnetic pole 10 as an actuator and/or as a position sensor includes a core 20 formed of a magnetic material, an input terminal 32, and an output terminal 33, and includes a coil part 31 wound around the core 20. The core 20 includes a filter unit 24 through which a magnetic flux generated by a common mode noise current occurring in the input terminal 32 and the output terminal 33, arranged in parallel to each other, passes.SELECTED DRAWING: Figure 1

Description

The present invention relates to magnetic poles and magnetic bearings.

Patent Document 1 discloses a magnetic bearing. The magnetic bearing rotatably supports the rotating shaft in a non-contact manner by levitating the rotating shaft by a magnetic force. The magnetic bearing has a magnetic pole as an actuator for generating a magnetic force. The actuator controls the magnetic force provided to the axis of rotation by controlling the current delivered to the coil wound around the core. Further, the magnetic bearing has a magnetic pole as a position sensor for obtaining the position information of the rotating shaft. The position sensor acquires the change in inductance according to the distance from the core around which the coil is wound to the axis of rotation as the change in voltage generated in the coil.

Patent No. 6244734

In recent years, it has been desired for rotary machines to have high rotation speed and / or high output. In order to increase the rotation and / or output of a rotating machine using a magnetic bearing, it is necessary to accurately control the position of the rotating shaft.

On the other hand, electromagnetic noise is likely to occur inside the rotating machine to which the magnetic bearing is applied. Common mode noise is one of the noises. Common mode noise occurs as a current flowing through the coil. For example, when a noise current is generated in the coil of the magnetic pole as an actuator, the noise current is superimposed on the drive current corresponding to the desired magnetic force, so that the intended control may not be performed. Further, when a noise current is generated in the coil of the magnetic pole as the position sensor, the voltage output from the position sensor may not accurately reflect the distance from the position sensor to the rotation axis. As a result, it becomes difficult to improve the control accuracy of the position of the rotating shaft.

Therefore, the present invention provides a magnetic pole and a magnetic bearing capable of improving the control accuracy of the position of the rotating shaft.

A magnetic pole according to an embodiment of the present invention comprises a core formed of a soft magnetic material and a coil having an input end and an output end and wound around the core, the cores juxtaposed with each other. Includes a filter section through which the magnetic flux generated by the common mode noise current generated at the input end and output end passes.

The core of the magnetic pole includes a filter portion through which the magnetic flux generated by the common mode noise current passes. Since this magnetic flux can be an impedance with respect to the common mode noise current, the magnitude of the common mode noise current can be reduced. Therefore, since the common mode noise current that can be noise is reduced, the magnetic bearing using the magnetic pole can accurately control the position of the rotating body.

In one embodiment, the core further includes a coil arrangement portion through which a coil portion formed between an input end portion and an output end portion is wound and a magnetic flux generated by a current flowing through the coil portion passes through. , May be provided at a position that does not overlap with the coil arrangement portion. According to this configuration, the region where the magnetic flux generated by the input end portion and the output end portion is generated is a position different from the region where the magnetic flux generated by the coil portion is generated. Therefore, it is possible to suppress the influence of each magnetic flux on each other.

In one embodiment, the core includes a coil arrangement portion and a core body, a filter portion includes a through hole formed in the core body, and the through hole is an input end portion and an output end portion juxtaposed with each other. May be inserted. According to this configuration, the filter unit can be formed by a simple configuration.

In one embodiment, the core includes a coil arrangement portion and a core body, a filter portion includes a groove formed in the core body, and the grooves are arranged with input ends and output ends juxtaposed with each other. May be done. According to this configuration, the input end portion and the output end portion can be wound around the grooved portion of the core body. Therefore, it is possible to generate a magnetic flux that becomes impedance more preferably.

In one form, the core includes a coil arrangement portion and a core body, the filter portion includes a hook portion having a T-shaped cross section formed in the core body, and the hook portion is an input juxtaposed with each other. Ends and output ends may be arranged. This configuration also makes it possible to wind the input end portion and the output end portion around the portion of the core body in which the hook portion is formed. Therefore, it is possible to generate a magnetic flux that becomes impedance more preferably.

Another form of the invention, the magnetic bearing, comprises an actuator that rotatably supports the axis of rotation in a non-contact manner and a position sensor that obtains information about the position of the axis of rotation, the actuator being the magnetic poles described above. This magnetic bearing includes the above magnetic pole as an actuator. Therefore, it is possible to generate a magnetic force that can accurately maintain the position of the rotating shaft. As a result, the position of the rotating shaft can be controlled with high accuracy.

In another embodiment, it further comprises an annular coring that surrounds the axis of rotation, at least two magnetic poles are arranged so as to surround the axis of rotation, and the core is formed between the input end and the output end. The coil portion to be wound is wound, and the coil arrangement portion through which the magnetic flux generated by the current flowing through the coil portion passes is further included, and the coil arrangement portion may protrude from the inner peripheral surface of the coring toward the axis of rotation. .. According to this configuration, a plurality of cores are integrated by coring. Then, the portion connecting the cores in the coring can be effectively utilized not only as a structural member but also electrically as a filter portion.

Yet another form of the magnetic bearing of the present invention comprises an actuator that rotatably supports the axis of rotation in a non-contact manner and a position sensor that obtains information about the position of the axis of rotation, wherein the position sensor is the magnetic pole described above. .. This magnetic bearing is provided with the above magnetic pole as a position sensor. Therefore, it is possible to obtain a voltage that accurately reflects the position of the rotating shaft. As a result, the position of the rotating shaft can be controlled with high accuracy.

In yet another embodiment, it further comprises an annular coring that surrounds the axis of rotation, with at least two magnetic poles arranged so as to surround the axis of rotation, the core being located between the input and output ends. The coil portion to be formed is wound, and further includes a coil arrangement portion through which the magnetic flux generated by the current flowing through the coil portion passes, even if the coil arrangement portion projects from the inner peripheral surface of the coring toward the axis of rotation. good. According to this configuration, a plurality of cores are integrated by coring. Then, the portion connecting the cores in the coring can be effectively utilized not only as a structural member but also electrically as a filter portion.

A magnetic bearing, which is another embodiment of the present invention, comprises a rotating shaft, a core surrounding the rotating shaft, a conducting wire attached to the core, a coil portion formed on the conducting wire and wound around the core, and a conducting wire. The input end, which extends from one end of the coil, and the output end, which is the part of the conductor that extends from the other end of the coil, and the input and output ends are in close proximity to each other. It is provided with a proximity portion that extends toward the core and an alignment portion that extends the input end portion and the output end portion in a mutually aligned manner from the coil portion via the proximity portion, and one of the alignment portion and the core has the other. Surrounding. This magnetic bearing can also reduce the magnitude of the common mode noise current. Therefore, since the common mode noise current that can be noise is reduced, the position of the rotating body can be controlled accurately.

INDUSTRIAL APPLICABILITY According to the present invention, a magnetic pole and a magnetic bearing capable of improving the control accuracy of the position of the rotating shaft are provided.

FIG. 1 is a perspective view of a rotating machine including a magnetic bearing using the magnetic poles of the embodiment. FIG. 2 is an enlarged front view showing the magnetic pole shown in FIG. 1. FIG. 3A is a perspective view showing the magnetic pole of the modified example 1. FIG. 3B is a perspective view showing the magnetic poles of the modified example 2. FIG. 4A is a perspective view showing the magnetic poles of the modified example 3. FIG. 4B is a perspective view showing the magnetic poles of the modified example 4. FIG. 5 is a perspective view showing the magnetic poles of the modified example 5.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description is omitted.

As shown in FIG. 1, the magnetic pole 10 and the magnetic bearing 1 are used in the rotary machine 100. Examples of the rotary machine 100 include a compressor. The compressor has a rotating shaft 101, a motor 102, and a pair of impellers (not shown). Impellers (not shown) are provided at both ends of the rotating shaft 101. A motor 102 is provided in the center of the rotating shaft 101. The motor 102 has a rotor 103 fixed to the rotating shaft 101 and a stator 104 surrounding the rotor 103.

The rotary shaft 101 is non-contactly and rotatably supported by a pair of magnetic bearings 1. The magnetic bearing 1 is arranged so as to sandwich the motor 102. In other words, the magnetic bearing 1 is arranged between the motor 102 and the impeller. A ball bearing 105 may be arranged between the motor 102 and the impeller. The ball bearing 105 rotatably supports the rotating shaft 101 when the magnetic bearing 1 has a defect in supporting the rotating shaft 101.

The magnetic bearing 1 supports the rotating shaft 101 in a non-contact and rotatable manner. Further, the magnetic bearing 1 controls the position of the rotating shaft 101 so as to stop at a predetermined position. This control is performed by applying a magnetic force to the rotating shaft 101 from a plurality of different directions so as to surround the rotating shaft 101. Therefore, the magnetic bearing 1 has an actuator that generates a magnetic force and a position sensor that obtains information about the position of the rotating shaft 101.

The actuator generates a magnetic force by providing an electric current to a conductor wound around a soft magnetic member. Further, the position sensor obtains information about the position of the rotating shaft 101 by utilizing the change of the inductance according to the position of the rotating shaft 101. As a member that functions in this way, the magnetic bearing 1 has a plurality of magnetic poles 10. The magnetic bearing 1 of FIG. 1 has four magnetic poles 10. In the example shown in FIG. 1, a configuration in which the magnetic pole 10 is used as an actuator is illustrated. Therefore, in the example shown in FIG. 1, the illustration of the position sensor is omitted.

The magnetic bearing 1 individually has a magnetic pole 10 used as an actuator and a magnetic pole (not shown) used as a position sensor. It should be noted that one magnetic pole 10 may exert the function of the actuator and the function of the position sensor.

Further, the magnetic bearing 1 has a control unit that controls the operation of the magnetic pole 10, but the control unit is not shown. The control unit obtains the position information of the rotating shaft 101 using the voltage obtained from the magnetic pole 10. The control unit controls the drive current applied to the magnetic pole 10 by using the position information.

The magnetic bearing 1 has a coring 2 and a magnetic pole 10 as main components. The coring 2 is an annular member that surrounds the rotating shaft 101. The coring 2 may be made of a soft magnetic material. The coring 2 holds a plurality of magnetic poles 10 at predetermined positions. This position is the relative relationship between the rotating shaft 101 and the magnetic pole 10. In this embodiment, the magnetic poles 10 are arranged around the rotation axis 101 every 90 degrees. In this embodiment, the coring 2 and the magnetic pole 10 are separate parts, and a structure in which the magnetic pole 10 is fitted into the coring 2 is illustrated. However, the coring 2 and the magnetic pole 10 may be an integral part. The case of being integrated will be described in Modification 5 described later.

FIG. 2 is an enlarged front view showing one magnetic pole 10. The magnetic pole 10 has a core 20 and a coil 30 as main components.

As a function of the actuator, the coil 30 receives an electric current to generate a magnetic flux. Further, as a function of the position sensor, the coil 30 causes a change in current according to a change in inductance. The core 20 controls the direction of the magnetic flux generated by the coil 30. Therefore, the core 20 is made of a so-called soft magnetic material. That is, the magnetic permeability of the core 20 is extremely higher than the magnetic permeability of air.

The core 20 has a core main body 21 and a coil arranging portion 22. The core 20 is a component in which the core main body 21 and the coil arranging portion 22 are integrally formed. The core 20 is formed by laminating plate-shaped members such as electrical steel sheets. The core body 21 is a portion fixed to the coring 2. The core body 21 exhibits, for example, a rectangular parallelepiped shape. The core main body 21 is arranged in the coring 2 so as to be along the tangential direction of the virtual circle centered on the rotation axis RL. The core main body 21 has a main body outer surface 21a and a main body inner surface 21b. The outer surface 21a of the main body faces the coring 2. In FIG. 2, the outer surface 21a of the main body is shown as a flat surface. The outer surface 21a of the main body is not limited to a flat surface and may be a curved surface. The internal surface 21b faces the rotation shaft 101. Similar to the main body outer surface 21a, the main body inner surface 21b is shown as a flat surface. The internal surface 21b is not limited to a flat surface and may be a curved surface.

The core 20 has a pair of coil arranging portions 22. Each of the coil arranging portions 22 extends from the inner surface 21b of the main body toward the rotation shaft 101. The coil arranging portion 22 exhibits, for example, a rectangular parallelepiped shape.

For example, the coil arranging portion 22 has a coil arranging surface 22a and a tip surface 22b. The coil arrangement surface 22a is a surface extending toward the rotation shaft 101. Therefore, the coil arrangement surface 22a does not face the rotating shaft 101. Assuming that the coil arrangement portion 22 has a rectangular parallelepiped shape, the coil arrangement surface 22a includes four surfaces. Further, if the coil arranging portion 22 has a cylindrical shape, the coil arranging surface 22a is a circumferential surface. The tip surface 22b is an end surface facing the rotation shaft 101.

One coil arranging portion 22 is separated from the other coil arranging portion 22 in the tangential direction of the virtual circle centered on the rotation axis RL. Therefore, when the core 20 is viewed from the front, it can be said that the overall shape of the core 20 is a π-shaped shape. The overall shape of the core 20 is not limited to the π-shaped shape. For example, the overall shape of the core 20 may be U-shaped. The magnetic flux MP1 formed by such an arrangement is received from the tip surface 22b of one coil arrangement portion 22 and finally output from the tip surface 22b of the other coil arrangement portion 22. More specifically, the magnetic flux MP1 passes through the inside of one coil arrangement portion 22, passes through the other coil arrangement portion 22 through a part of the core body 21, and then the tip surface of the other coil arrangement portion 22. It reaches 22b.

The coil 30 (conductor A) is composed of one conductor or a plurality of conductors connected in series with each other. The coil 30 includes a pair of coil portions 31, an input end portion 32, and an output end portion 33.
The pair of coil portions 31 are formed between the input end portion 32 and the output end portion 33. Therefore, the pair of coil portions 31 are electrically connected in series with each other. One coil portion 31 is wound around one coil arrangement portion 22. Similarly, the other coil portion 31 is wound around the other coil arrangement portion 22.

When the coil 30 is a single conductor, the input end 32 and the output end 33 are both ends of the one conductor. The input end 32 receives current from an external power source. Further, the output end 33 outputs a current. That is, the input end portion 32 and the output end portion 33 are defined by the mode of input and output of the current.
Further, the magnetic pole 10 has a filter function of reducing noise generated in the coil 30. This filter function reduces so-called common mode noise generated in the coil 30. The common mode noise is a common mode current generated in the coil 30.

When the magnetic pole 10 is used as an actuator, the current flowing through the coil 30 of the magnetic pole 10 may include a current due to common mode noise in addition to the drive current. As a result, the command value output from the control unit and the value of the current actually flowing through the coil 30 are different. Therefore, the accuracy of the position control of the rotating shaft 101 performed by the actuator may decrease.

When the magnetic pole 10 is used as a position sensor, the current flowing through the coil 30 may include a current due to common mode noise in addition to the current corresponding to the change in inductance. In this case, the output voltage of the magnetic pole 10 based on the current flowing through the coil 30 is different from the output voltage corresponding to the distance from the actual magnetic pole 10 to the rotating shaft 101. That is, the position indicated by the output of the position sensor deviates from the position of the actual rotation axis 101. As a result, the position control is performed based on the result including the deviation, so that the accuracy of the position control of the rotating shaft 101 may decrease.

The input end portion 32 is a conducting wire extending from one end side of the coil portion 31. Further, the output end portion 33 is a conducting wire extending from the other end side of the coil portion 31. That is, the input end portion 32 and the output end portion 33 are continuous via the coil portion 31. The input end portion 32 extends from one end of the coil portion 31 toward the core main body 21. Further, the output end portion 33 extends from the other end of the coil portion 31 toward the core main body 21. In this embodiment, one end and the other end of the coil portion 31 are separated from each other. The input end 32 and the output end 33 are in close proximity to each other toward the core body 21. That is, the coil 30 (conductor A) is formed with a proximity portion B in which the input end portion 32 and the output end portion 33 are close to each other.

The core 20 has a through hole 23 provided in the core body 21. The through hole 23 is formed on the outer surface 21a side of the main body 21 of the core main body 21. For example, the distance from the through hole 23 to the outer surface 21a of the main body is smaller than the distance from the through hole 23 to the inner surface 21b of the main body. Therefore, the through hole 23 is separated from the coil arrangement portion 22. Further, in the example shown in FIG. 2, the through hole 23 is formed at a corner portion of the core main body 21. The through hole 23 may be formed in the vicinity of the outer surface 21a of the main body. For example, the through hole 23 may be formed at a corner portion on the opposite side of the drawing. Further, the through hole 23 may be formed between the pair of coil arranging portions 22.

The input end portion 32 and the output end portion 33 reach the through hole 23 via the proximity portion B. The input end portion 32 and the output end portion 33 extend from the coil portion 31 and are both inserted through one opening of the through hole 23. In the through hole 23, the input end portion 32 and the output end portion 33 extend so as to be aligned with each other. That is, in the coil 30 (conductor wire A), the portion inserted through the through hole 23 is the aligned portion C. Further, the through hole 23 surrounds the aligned portion C, and the through hole 23 is formed in the core 20. That is, in the present embodiment, the core 20 surrounds the aligned portion C.

Further, it will be described from the viewpoint of magnetic flux. The magnetic pole 10 has a portion where the magnetic flux MP1 caused by the pair of coil portions 31 is generated. The portion provided with the through hole 23 does not overlap with the portion where the magnetic flux MP1 is generated.

An input end portion 32 and an output end portion 33 are inserted through the through hole 23. The current flowing through the input end 32 and / or the output end 33 generates a magnetic flux MP2 in the core body 21 existing around the through hole 23. That is, a part of the through hole 23 and the core main body 21 surrounding the through hole 23 constitutes the filter portion 24.

Here, the direction of the drive current flowing through the input end portion 32 is opposite to the direction of the drive current flowing through the output end portion 33. Then, the direction of the magnetic flux generated by the drive current flowing through the input end portion 32 is opposite to the direction of the magnetic flux generated by the drive current flowing through the output end portion 33. Therefore, no magnetic flux that interferes with the drive current is generated.

On the other hand, the common mode noise current flowing through the input end portion 32 is the same as the direction of the common mode noise current flowing through the output end portion 33. Therefore, the common mode noise current generates the magnetic flux MP2 in the core body 21. Then, this magnetic flux MP2 is generated in a direction that interferes with the common mode noise current. That is, the core body 21 functions as an inductor. In short, the input end portion 32 and the output end portion 33 inserted through the through hole 23 and a part of the core main body 21 around the through hole 23 cooperate to exert a function as a so-called choke coil.

In order to perform the above functions, the inner diameter of the through hole 23 is at least twice the diameter of the conducting wire constituting the coil 30. Further, the inner diameter of the through hole 23 may correspond to the magnitude of the magnetic flux MP2.

<Action effect>
The magnetic pole 10 includes a core 20 made of a soft magnetic material, and a coil 30 having an input end 32 and an output end 33 and wound around the core 20. The core 20 includes a filter unit 24 through which the magnetic flux MP2 generated by the common mode noise current generated in the input end portion 32 and the output end portion 33 juxtaposed with each other passes.

The core 20 of the magnetic pole 10 includes a filter unit 24 through which the magnetic flux MP2 generated by the common mode noise current passes. Since this magnetic flux MP2 can be an impedance with respect to the common mode noise current, the magnitude of the common mode noise current can be reduced. Therefore, since the common mode noise current that can be noise is reduced, the magnetic bearing 1 using the magnetic pole 10 can accurately control the position of the rotating shaft 101.

If the control accuracy of the position of the rotating shaft 101 is improved, the speed of the rotating shaft 101 can be increased.

Further, since the width of the position fluctuation when the rotating shaft 101 is rotating becomes small, the position fluctuation of the impeller attached to the rotating shaft 101 also becomes small. The impeller is arranged with a predetermined gap between the impeller and the housing accommodating the impeller to allow the position change of the impeller. As described above, when the position fluctuation of the impeller is suppressed, this gap can be set small. As a result, the energy loss of the fluid due to the existence of the gap is suppressed, so that the output of the rotary machine 100 can be further improved.

The inside of the rotating machine in which the magnetic bearing 1 is used often has a high temperature. Further, the internal space of the rotary machine 100 is extremely limited from the viewpoint of miniaturization. It is not desirable to place new parts in such a high temperature and narrow space. For example, from the viewpoint of removing common mode noise, it is conceivable to arrange an electric component such as a choke coil. However, when arranging electrical parts in a high temperature environment, it is necessary to adopt parts having high temperature resistance, and it is also necessary to prepare a space for arranging the parts.

On the other hand, the magnetic pole 10 of the present embodiment can exert the effect of removing common mode noise without adding a new component. That is, the magnetic pole 10 exerts a filter function by providing a through hole 23 in the core main body 21 which is originally provided and arranging a pair of conducting wires in the through hole 23. Therefore, there is no problem with temperature tolerance and there is no need to prepare space for new components.

The magnetic pole 10 can reduce common mode noise in the vicinity of the coil portion 31. Therefore, it is advantageous to generate a magnetic force for levitating the rotating shaft 101. Similarly, it is also advantageous from the viewpoint of obtaining a voltage for detecting the position of the rotating shaft 101.

The core 20 further includes a coil arranging portion 22 through which the coil 30 is wound and the magnetic flux MP1 generated by the wound coil 30 passes through. The filter unit 24 is provided at a position that does not overlap with the coil arrangement unit 22. According to this configuration, the region where the magnetic flux MP2 caused by the input end portion 32 and the output end portion 33 is generated is a position different from the region where the magnetic flux MP1 caused by the coil portion 31 is generated. Therefore, it is possible to suppress the influence of the respective magnetic fluxes MP1 and MP2 on each other.

Further, since the through hole 23 constituting the filter portion 24 is not formed in the region where the magnetic flux MP1 is formed, the area through which the magnetic flux MP1 passes is not limited. That is, it is possible to suppress the occurrence of saturation of the magnetic flux MP1 in the region where the magnetic flux MP1 is formed.

The core 20 includes a coil arranging portion 22 and a core body 21. The filter portion 24 includes a through hole 23 formed in the core body 21. An input end portion 32 and an output end portion 33 juxtaposed with each other are inserted through the through hole 23. According to this configuration, the filter unit 24 can be formed by a simple configuration.

The magnetic bearing 1 includes a magnetic pole 10 as an actuator that rotatably supports the rotating shaft 101 in a non-contact manner, and a position sensor (not shown) for obtaining information on the position of the rotating shaft 101. The magnetic bearing 1 includes a magnetic pole 10 as an actuator. Therefore, it is possible to generate a magnetic force that can accurately maintain the position of the rotating shaft 101. As a result, the position of the rotating shaft 101 is controlled with high accuracy, so that the rotating shaft 101 can be rotated at a high speed.

The present invention has been described in detail above based on the embodiments thereof. However, the present invention is not limited to the above embodiment. The present invention can be modified in various ways without departing from the gist thereof.

<Modification 1>
The filter portion 24 is not limited to the through hole 23 provided in the core main body 21. As shown in FIG. 3A, the filter portion 24A of the magnetic pole 10A of the modification 1 may be a groove 25 provided in the core main body 21A. It can be said that such a filter unit 24A has a slit structure. The groove 25 is provided on the inner surface 21b of the core body 21A. The groove 25 includes an opening formed in the inner surface 21b of the main body and extends from the inner surface 21b of the main body toward the outer surface 21a of the main body. Further, the groove 25 penetrates from one main body side surface 21c of the core main body 21A toward the other main body side surface 21c. That is, the groove 25 includes an opening formed in one main body side surface 21c and an opening formed in the other main body side surface 21c.
Then, in the example of FIG. 3A, the groove 25 is provided on the outside of the pair of coil arranging portions 22. According to this arrangement, the filter unit 24A can be provided outside the magnetic flux MP1 generated by the pair of coil units 31 wound around the pair of coil arrangement units 22. The input end portion 32 and the output end portion 33 are wound along the bottom surface 25a, the main body side surface 21c, and the main body outer surface 21a of the groove 25. There is no particular limit to the number of turns.

Also in this modification, the coil 30 (conductor A) is formed with a proximity portion B in which the input end portion 32 and the output end portion 33 are close to each other. The input end portion 32 and the output end portion 33 reach the opening of the groove 25 of one of the main body side surfaces 21c of the core main body 21A via the proximity portion B (the opening is inserted). That is, the input end portion 32 and the output end portion 33 are inserted from the same opening surface. Further, the input end portion 32 and the output end portion 33 are wound around the groove 25 and the core body 21A so as to be aligned with each other. That is, in the coil 30 (conductor wire A), the portions wound around the groove 25 and the core main body 21A are aligned portions C. In this modification, the input end portion 32 and the output end portion 33 are both wound left-handed with respect to the groove 25 and the core body 21A. Here, the left-handed winding is the winding direction when viewed along the direction extending from the coil portion 31. Further, the input end portion 32 and the output end portion 33 are attached to the groove 25 and the core main body 21A with the same number of windings. Although it is left-handed in this modification, it may be right-handed. Further, the aligned portion C is wound around the core 20. That is, in this modification, the aligned portion C surrounds the core 20.

According to such an arrangement of the input end portion 32 and the output end portion 33, the core main body 21A is arranged in a part around the conducting wire forming the input end portion 32 and the output end portion 33. Since it is only necessary to generate the magnetic flux MP2 that becomes the impedance, the core body 21A does not have to be arranged all around the conductor wire forming the input end portion 32 and the output end portion 33. If it is specified that the element based on the magnetic permeability of the core body 21A and the element based on the magnetic permeability of air are connected in series around the conductor, an impedance that can reduce the common mode noise current can be generated. Sufficient. Also with this configuration, the same effect as that of the magnetic pole 10 of the embodiment can be obtained.

<Modification 2>
Like the magnetic pole 10B of the modification 2 of FIG. 3B, the core main body 21B may be provided with a groove 26 not only on the inner surface 21b of the main body but also on the outer surface 21a of the main body. That is, the filter unit 24B is composed of grooves 25 and 26. The groove 26 is provided at a position facing the groove 25. In other words, in the configuration of the first modification, the groove 26 is provided at the position of the outer surface 21a of the main body through which the wound conductor wire passes. According to this configuration, the wound lead wire does not protrude from the inner surface 21b of the main body and the outer surface 21a of the main body. Therefore, the expansion of the dimension of the magnetic pole 10B due to the winding is suppressed. Further, a groove (not shown) may be provided on the side surface 21c of the main body. Also with this configuration, the same effect as that of the magnetic pole 10 of the embodiment can be obtained.

<Modification 3>
The configuration for winding the conductor is not limited to the groove structure as shown in FIGS. 3 (a) and 3 (b). For example, the magnetic pole 10C of the modification 3 shown in FIG. 4A has a hook portion 27 provided on the core main body 21C. It can be said that the structure of such a filter unit 24C is a hook-shaped structure. The hook portion 27 is arranged in a recess 28 provided on the outer surface 21a of the main body. It can be said that the recess 28 is a groove having a large width. The hook portion 27 stands up from the bottom surface 28a of the recess 28 toward the outer surface 21a of the main body. The hook portion 27 has a pillar portion 27a and a flange portion 27b. The pillar portion 27a extends from the bottom surface 28a toward the outer surface 21a of the main body. A flange portion 27b is provided at the tip of the pillar portion 27a. The flange portion 27b is substantially flush with the outer surface 21a of the main body. The width of the flange portion 27b is narrower than the width of the recess 28. On the other hand, the width of the flange portion 27b is wider than the width of the pillar portion 27a. Therefore, the hook portion 27 has a T-shaped cross section when viewed from the front. The conducting wire forming the input end portion 32 and the output end portion 33 is wound around the pillar portion 27a. Since the width of the flange portion 27b is wider than that of the pillar portion 27a, the wound conductor does not come off. Even with such a configuration, the same effect as that of the magnetic pole 10 of the embodiment can be obtained. In FIG. 4A, the side surface of the pillar portion 27a is flush with the main body side surface 21c. However, the side surface of the pillar portion 27a may be recessed with respect to the main body side surface 21c. According to this configuration, the wound lead wire does not protrude from the inner surface 21b of the main body and the outer surface 21a of the main body. Therefore, the expansion of the dimension of the magnetic pole 10C due to the winding is suppressed.

This modified example also has the same configuration as the modified example 1. That is, the coil 30 (conductor A) is formed with a proximity portion B in which the input end portion 32 and the output end portion 33 are close to each other. Further, the input end portion 32 and the output end portion 33 are along the side surface of the pillar portion 27a via the proximity portion B. The input end portion 32 and the output end portion 33 are aligned with each other and wound around the pillar portion 27a to form the aligned portion C. Further, the input end portion 32 and the output end portion 33 are both left-handed and have the same number of turns.

In the modified example 3, the recess 28 and the hooking portion 27 are provided on the outer surface 21a side of the core body 21C. For example, the recess 28 and the hook portion 27 may be provided on the inner surface 21b side of the core body 21C.

<Modification example 4>
Further, the hooking portion 27 does not have to be arranged in the recess 28 like the core main body 21D provided in the magnetic pole 10D of the modification 4 shown in FIG. 4 (b). In this configuration, the hooking portion 27 constituting the filter portion 24D protrudes from the outer surface 21a of the main body. According to the hook portion 27 of the modification 4, the conducting wire can be easily wound. As in the modified example 3, the hooking portion 27 may protrude from the main body inner surface 21b of the core main body 21C.

<Modification 5>
In the magnetic bearing 1 of the embodiment, the magnetic pole 10 and the coring 2 are separate parts. As in the magnetic bearing 1E of the modified example 5 shown in FIG. 5, the magnetic pole 10E and the coring 2E may be integrated. The pair of coil arranging portions 22E project from the inner peripheral surface 2a of the annular coring 2E surrounding the rotating shaft 101 toward the rotating shaft 101. The coring 2E is provided with a through hole 23E through which the conducting wires constituting the input end portion 32 and the output end portion 33 are passed. According to this configuration, a plurality of magnetic poles 10E are integrated by the coring 2. Then, the portion of the coring 2 that connects the magnetic poles 10E to each other can be effectively utilized not only as a structural member but also electrically as a filter portion 24E.

Note that FIG. 5 illustrates a configuration having a through hole 23E as the filter portion 24E. Even when the magnetic pole 10E and the coring 2E are integrated, the configurations shown in the modified examples 1 to 4 can be applied as the filter unit.

Further, the magnetic bearing may be provided with a choke coil if necessary.

1,1E Magnetic bearing 2, 2E Coring 2a Inner peripheral surface 10, 10A, 10B, 10C, 10D, 10E, 10D Magnetic flux 20 Core 21, 21A, 21B, 21C Core body 22 Coil arrangement part 22a Coil arrangement surface 22b Tip surface 23 Through holes 24, 24A, 24B, 24C, 24D, 24E Filter part 25 Groove 25a Bottom 26 Groove 27 Hook part 27a Pillar part 27b Flange part 28 Recess 28a Bottom 30 Coil 31 Coil part 32 Input end 33 Output end 101 Rotation Shaft 102 Motor 103 Rotor 104 Stator 105 Ball bearing MP1, MP2 Magnetic flux RL Rotor axis A Lead wire B Proximity part C Alignment part

Claims (10)

With a core made of soft magnetic material,
A coil having an input end and an output end and wound around the core.
The core is
A magnetic pole including a filter portion through which a magnetic flux generated by a common mode noise current generated at the input end portion and the output end portion juxtaposed with each other passes. The core further includes a coil arrangement portion through which a coil portion formed between the input end portion and the output end portion is wound and a magnetic flux generated by a current flowing through the coil portion passes through.
The magnetic pole according to claim 1, wherein the filter portion is provided at a position that does not overlap with the coil arrangement portion. The core includes the coil arrangement portion and the core body.
The filter portion includes a through hole formed in the core body.
The magnetic pole according to claim 2, wherein the input end and the output end juxtaposed with each other are inserted into the through hole. The core includes the coil arrangement portion and the core body.
The filter portion includes a groove formed in the core body.
The magnetic pole according to claim 2, wherein the input end and the output end juxtaposed with each other are arranged in the groove. The core includes the coil arrangement portion and the core body.
The filter portion includes a hook portion having a T-shaped cross section formed on the core body.
The magnetic pole according to claim 2, wherein the input end and the output end juxtaposed with each other are arranged on the hook. An actuator that rotatably supports the axis of rotation in a non-contact manner,
A position sensor for obtaining information on the position of the rotation axis is provided.
The actuator is a magnetic bearing which is the magnetic pole according to any one of claims 1 to 5. Further provided with an annular coring that surrounds the axis of rotation
At least two magnetic poles are arranged so as to surround the axis of rotation.
The core further includes a coil arrangement portion through which a coil portion formed between the input end portion and the output end portion is wound and a magnetic flux generated by a current flowing through the coil portion passes through.
The magnetic bearing according to claim 6, wherein the coil arrangement portion projects from the inner peripheral surface of the coring toward the rotation axis. An actuator that rotatably supports the axis of rotation in a non-contact manner,
A position sensor for obtaining information on the position of the rotation axis is provided.
The position sensor is a magnetic bearing which is the magnetic pole according to any one of claims 1 to 5. Further provided with an annular coring that surrounds the axis of rotation
At least two magnetic poles are arranged so as to surround the axis of rotation.
The core further includes a coil arrangement portion through which a coil portion formed between the input end portion and the output end portion is wound and a magnetic flux generated by a current flowing through the coil portion passes through.
The magnetic bearing according to claim 8, wherein the coil arrangement portion projects from the inner peripheral surface of the coring toward the rotation axis. The axis of rotation and
The core that surrounds the axis of rotation,
The conductor attached to the core and
A coil portion formed on the conducting wire and wound around the core,
An input end portion of the conducting wire, which is a portion extending from one end of the coil portion, and
The output end portion of the conducting wire, which is a portion extending from the other end of the coil portion,
A proximity portion in which the input end portion and the output end portion are close to each other and extend toward the core, and a proximity portion.
The coil portion is provided with an aligned portion in which the input end portion and the output end portion extend in a mutually aligned manner via the proximity portion.
A magnetic bearing in which one of the alignment and the core surrounds the other.

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