JP3793863B2 - Manufacturing method of stator unit of magnetic bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention relates to a method of manufacturing a stator unit of the magnetic bearing. More particularly, to a method of manufacturing a stator unit of the radial magnetic bearing in a non-contact support the rotating member in the radial direction (radial direction) by a plurality of electromagnets disposed around the rotor.
[0002]
[Prior art]
As a stator unit of this type of radial magnetic bearing, for example, the one shown in FIG. 7B is known.
[0003]
The stator unit (1) includes a stator housing (11) disposed around a shaft-like rotating body (10), and four electromagnets (12) fixed to the housing (11) at equal intervals in the circumferential direction. ). Each electromagnet (12) includes a core (13) fixed to the housing (11) and a coil (14) wound around the core (13).
[0004]
The electromagnet of the magnetic bearing includes a prismatic core extending in the radial direction, and a heteropolar type including a substantially horseshoe-shaped core in which magnetic pole portions projecting radially inward are formed at both ends of a connecting portion extending in the circumferential direction. And a so-called homopolar type having a substantially horseshoe-shaped core in which magnetic pole portions protruding radially inward are formed at both ends of a connecting portion extending in the axial direction. The core of the electromagnet is made by laminating magnetic plates such as silicon steel plates. A prismatic core or heteropolar type electromagnet core can be made by laminating magnetic plates in the axial direction, but homopolar type electromagnet cores cannot do so, and magnetic plates are laminated in the circumferential direction. Is made by.
[0005]
The electromagnet (12) of the stator unit (1) shown in FIG. 7 (b) is a homopolar type, and the core (13) has the magnetic pole portions (13b) at both ends of the connecting portion (13a) as described above. By laminating a plurality of magnetic plates (15) formed in a circumferential direction, with magnetic pole portions (13b) formed integrally at both ends of the portion forming the connecting portion (13a). It is made. A coil (14) is wound around each magnetic pole part (13b). Further, the inner surface (13c) of the core (13) of each electromagnet (12), that is, the inner surface (13c) of each magnetic pole portion (13b) is one common cylindrical surface corresponding to the outer peripheral cylindrical surface of the rotating body (10). It is formed to become. The gap between the outer peripheral surface of the rotating body (10) and the inner surface (13c) of the core (13) of each electromagnet (12) is very small, and high accuracy is required for the inner surface (13c) of the core (13). The
[0006]
The stator unit is manufactured as follows, for example.
[0007]
First, a stator unit material (2) as shown in FIG. This material (2) is obtained by fixing four electromagnets (12) to a housing (11). Each electromagnet (12) includes a core (13) fixed to the housing (11) and a coil (14) wound around the core (13). The core (13) has a magnetic pole part (13b) formed at both ends in the axial direction of the connecting part (13a) extending in the axial direction, and the magnetic pole part (13b) is provided at both ends of the part forming the connecting part (13a). It is made by laminating a plurality of magnetic plates (15) of the same shape, in which the portions to be formed are integrally formed, in the circumferential direction. A coil (14) is wound around each magnetic pole part (13b). The inner surface (13d) of the magnetic pole part (13b) of each core (13) is a substantially flat surface parallel to the axis. Next, the inner part in the radial direction including the inner surface (13d) of the magnetic pole part (13b) of the core (13) of the stator unit material (2) is processed by an appropriate means such as grinding, and FIG. A cylindrical inner surface (13c) as shown is formed to complete the stator unit (1).
[0008]
When the magnetic pole part (13b) of the core (13) is machined by grinding or the like as described above, a circumferential machining force acts on the magnetic pole part (13b), but this part (13b) acts as a magnetic plate (15). In other words, the tip of the magnetic plate (15), particularly toward the end in the circumferential direction, is deformed and scattered in the circumferential direction. For this reason, it is difficult to accurately process the cylindrical surface of the inner surface (13c) of the core (13).
[0009]
Some stator units of magnetic bearings have three electromagnets fixed to the stator housing, but there are similar problems in this case.
[0011]
[Problems to be solved by the invention]
The purpose of this invention is to prevent loose magnetic plates during core processing, to provide a method capable of producing an accurate magnetic bearing stator unit of the cylindrical surface of the inner surface of the core of the electromagnet is there.
[0023]
[Means for Solving the Problems and Effects of the Invention]
The invention of claim 1 includes a stator housing disposed around the rotating body, and a plurality of electromagnets fixed to the stator housing at intervals in the circumferential direction, wherein each of the electromagnets includes a plurality of magnetic plates. A core having a pair of magnetic pole portions formed by being laminated in the circumferential direction and projecting radially inward from both ends of a connecting portion extending in the axial direction, and a coil wound around each magnetic pole portion of each electromagnet A method of manufacturing a stator unit of a magnetic bearing provided with an electromagnet having a core in which a plurality of magnetic plates having the same shape are stacked, fixed to the stator housing, and adjacent to the circumferential direction in the magnetic pole portion of the electromagnet In the state in which the core spacing holder made of a prismatic non-magnetic material is in pressure contact with the opposing surface on the radially inner side of the coil of the magnetic pole part and in contact with the surface facing the radially inner side of the coil Through And a second step of processing the inner surface of the portion of the stator unit material, which is a combination of the core and the core spacing holder, into one common cylindrical surface. It is characterized by this.
[0024]
The electromagnet is a homopolar type, and as described above, the core must be formed by laminating magnetic plates in the circumferential direction, but a core spacing holder is interposed between the cores of the electromagnets adjacent in the circumferential direction. Then, the inner surface of the core and the inner surface of the core spacing holder are processed with the circumferential pressure applied to the core, so that the tip of the magnetic plate is deformed and scattered in the circumferential direction by the processing force. There is no. For this reason, the cylindrical surface of the inner surface of the core can be processed with high accuracy. In addition, since the core spacing member is made of a non-magnetic material, it does not adversely affect the magnetic characteristics of the electromagnet even if it is left as it is after processing.
[0025]
Therefore, according to the first aspect of the present invention, it is possible to prevent the magnetic plate from being scattered at the time of core processing, and to accurately process the cylindrical surface of the inner surface of the core, and to improve the accuracy of the cylindrical surface of the inner surface of the electromagnet core. A good homopolar magnetic bearing stator unit can be manufactured.
[0034]
The invention of claim 2 comprises a stator housing disposed around the rotating body, and a plurality of electromagnets fixed to the stator housing at intervals in the circumferential direction, wherein each of the electromagnets includes a plurality of magnetic plates. A core having a pair of magnetic pole portions formed by being laminated in the circumferential direction and projecting radially inward from both ends of a connecting portion extending in the axial direction, and a coil wound around each magnetic pole portion of each electromagnet A method of manufacturing a stator unit of a magnetic bearing provided with an electromagnet having a core in which a plurality of magnetic plates having the same shape are stacked, fixed to the stator housing, and adjacent to the circumferential direction in the magnetic pole portion of the electromagnet during, prismatic core distance holder is, as well as pressed against the facing surface of the radially inward from the coil of the magnetic pole portions, is interposed in a state of being pressed against the surface facing the radially inner side of the coil A first step of producing a theta unit material, a second step of processing an inner surface of a portion of the stator unit material core and a core interval holding body to form one common cylindrical surface, and the core interval holding A third step of removing the body is included.
[0035]
In the stator unit manufactured by this method, the core spacing holder is removed, but the core spacing holder is interposed between the adjacent electromagnet cores when processing the core. The cylindrical surface of the inner surface of the core can be processed with high accuracy by preventing deformation and scattering of the tip end portion of the magnetic plate. Therefore, according to this method, a stator unit of a homopolar magnetic bearing with a high accuracy of the cylindrical surface of the inner surface of the core of the electromagnet can be manufactured.
[0036]
In addition, since a core space | interval holding body is removed after manufacture, the material is arbitrary and can use the appropriate material with favorable workability.
[0043]
For example, in the first or second aspect of the invention , in the first step, one common core spacing member is interposed between the magnetic pole portions at both ends of the core of the electromagnet adjacent in the circumferential direction. Make stator unit material.
[0044]
In this case, it is possible to prevent deformation and scattering of the magnetic plate at the time of processing at the magnetic pole portions at both ends of the cores of the adjacent electromagnets by one core spacing holder .
[0045]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, with reference to FIGS, illustrating embodiments of the present invention.
[0046]
1 to 3 is of the radial magnetic bearing stator unit (3), 4 and 5 show the course of the stator unit material for producing a stator unit (3) and (4) respectively.
[0047]
As shown in FIGS. 1 to 3, the stator unit (3) is fixed inside a cylindrical housing member (16) that constitutes a part of the housing of the magnetic bearing device.
[0048]
The stator unit (3) includes a substantially cylindrical stator housing (17) disposed around the vertical axis rotating body (10), and a plurality of stator units fixed to the housing (17) at equal intervals in the circumferential direction. And four electromagnets (18) in this example. Each electromagnet (18) includes a core (19) fixed to the housing (17) and a coil (20) wound around the core (19). Each electromagnet (18) is of a homopolar type, and the core (19) is formed with a magnetic pole portion (19b) extending radially inward at both axial ends of a connecting portion (19a) extending in the axial direction (vertical direction). A magnetic plate (21) made of, for example, a silicon steel plate, in which the portions forming the magnetic pole portion (19b) are integrally formed at both ends of the portion forming the connecting portion (19a), is laminated in the circumferential direction. Is made by. A coil (20) is wound around each magnetic pole part (19b).
[0049]
A rectangular notch (22) extending from the upper end surface to near the lower end is formed at a plurality of locations (four locations in this example) that equally divide the peripheral wall of the housing (17) in the circumferential direction, and each notch (22) The connecting portion (19a) of the core (19) of each electromagnet (18) is fitted and fixed by a bolt (23). The magnetic pole portion (19b) of the core (19) protrudes radially inward from the peripheral wall portion of the housing (17).
[0050]
The housing (17) of the stator unit (3) is concentrically fitted inside the housing member (16) and is fixed by bolts (24).
[0051]
A plurality of (four in this example) core interval holders (25) having a vertical column shape are interposed one by one between the cores (19) of the electromagnets (18) adjacent in the circumferential direction. The holding body (25) is made of a nonmagnetic material such as bakelite, for example. The upper part of each holding body (25) is in pressure contact with the opposing surface on the radially inner side from the coil (20) of the upper magnetic pole part (19b) of the adjacent core (19) and protrudes in the circumferential direction from this opposing surface The lower part of each holding body (25) is pressed against the radially inward portion of (20), and the lower surface of the holding body (25) is the opposing surface radially inward from the coil (20) of the lower magnetic pole part (19b) of the adjacent core (19) And is in pressure contact with the portion facing the radially inner side of the coil (20) protruding in the circumferential direction from the facing surface. The entire holding body (25) compresses the circumferential direction on the magnetic plate (21) in the radially inner portion of the coil (20) of the upper and lower magnetic pole portions (19b) of the core (19) of the entire electromagnet (18). A force acts, and a radially outward force acts on a portion protruding in the circumferential direction from the magnetic pole portion (19b) of each coil (20).
[0052]
The rotating body (10) is concentrically disposed inside the electromagnet (18) and the holding body (25) of the stator unit (3). Then, the radially inner surface (inner surface) (19c) of the upper and lower magnetic pole portions (19b) of the core (19) of each electromagnet (18) and the radially inner surface (inner surface) of each holder (25) (25c) ) Is formed to be one common cylindrical surface corresponding to the outer peripheral surface of the rotating body (10). In the upper and lower magnetic pole portions (19b), these surfaces (19c) and (25c) form one complete cylindrical surface continuous in the circumferential direction.
[0053]
A target (26) made of a stripping material (integral material) of a magnetic material having a higher specific resistance than that of a silicon steel plate or the like is fixed to a portion of the outer periphery of the rotating body (10) facing the electromagnet (18). In addition, a displacement sensor (27) for detecting the radial displacement of the rotating body (10) is attached to the portion of the housing member (16) directly below each electromagnet (18), and the rotation sensor is opposed to the rotation sensor. A target (28) is fixed to the outer periphery of the body (10).
[0054]
The electromagnet (18) and the displacement sensor (27) are connected to a magnetic bearing control device (not shown). An excitation current is supplied from the magnetic bearing control device to each coil (20) of each electromagnet (18), and each magnetic pole part (19b) is excited, whereby the rotating body (10) is attracted radially outward. The non-contact is supported at a predetermined position in the radial direction. The magnetic bearing control device controls the excitation current of each electromagnet (18) based on the output of the displacement sensor (27), thereby controlling the radial position of the rotating body (10). In each electromagnet (18), the upper and lower magnetic pole portions (19b) are excited to have opposite polarities. For all the electromagnets (18), the upper magnetic pole portion (19b) is excited to the same polarity, and the lower magnetic pole portion (19b) is excited to the same polarity opposite thereto.
[0055]
The magnetic bearing device is usually provided with two sets of the radial magnetic bearing stator units (3) as described above. In addition, a set of axial magnetic bearing stator units for supporting the rotating body (10) in a non-contact manner in the axial direction and a built-in electric motor for rotating the rotating body (10) at high speed are provided. The rotating body (10) is rotated at a high speed by the electric motor while being supported in a non-contact manner by the radial magnetic bearing and the axial magnetic bearing.
[0056]
When the stator unit of the radial magnetic bearing includes the heteropolar type electromagnet, the magnetic poles at both ends in the circumferential direction are excited in opposite polarities in each electromagnet, so that the magnetic poles having the opposite polarity in the rotating direction of the rotating body. Will be lined up four by four. For this reason, the change of the magnetic flux in the rotation direction of the rotating body is large, and an eddy current is generated on the surface of the rotating body due to the rotation, resulting in a large rotation loss. In order to suppress the generation of eddy currents on the surface of the rotating body, conventionally, a target is formed by laminating a plurality of magnetic plates made of silicon steel plates in the axial direction with an insulating material interposed therebetween. However, if this is done, there is a problem that magnetically there is a gap between the magnetic plates adjacent in the axial direction, which adversely affects the basic performance of the electromagnet.
[0057]
On the other hand, in the above stator unit (3), the upper magnetic pole part (19b) of all the electromagnets (18) has the same polarity, and the lower magnetic pole part (19b) has the same polarity opposite to this. Therefore, the change of the magnetic flux around the target (26) of the rotating body (10) facing the upper magnetic pole part (19b) and the rotation around the target (26) facing the lower magnetic pole part (19b) Both changes in direction magnetic flux are reduced. For this reason, even if the target (26) is made of a stripping material, the eddy current generated on the surface thereof is small and the rotation loss is small. Further, since the target (26) is made of a magnetic material having a higher specific resistance than a silicon steel plate or the like, the eddy current is further reduced even if it is a stripping material. In addition, since the stripping material is used for the target (26), the above-described problem that occurs when the magnetic plates are laminated does not occur.
[0058]
The stator unit (3) is manufactured as follows, for example.
[0059]
First, a stator unit material (4) as shown in FIGS. 4 and 5 is made. In this material (4), four electromagnets (18) are fixed to the housing (17), except for the core (19) and core spacing holder (25) of each electromagnet (18). It has the same configuration as the completed stator unit (3). The core (19) is formed by laminating a plurality of magnetic plates (21) having the same shape in which the portions forming the magnetic pole portion (19b) are integrally formed at both ends of the portion forming the connecting portion (19a) in the circumferential direction. The inner surface (19d) of each magnetic pole part (19b) of each core (19) is a substantially flat surface parallel to the axis. Each spacing member (25) has a square prism shape with a horizontal cross section (transverse cross section), and two adjacent surfaces on the radially inner side are opposed to the magnetic pole portion (19b) of the electromagnet (18) adjacent in the circumferential direction. The other two surfaces adjacent to each other on the outer side in the radial direction are in pressure contact with the surface facing the inner side in the radial direction of the coil (20) of the adjacent electromagnet (18), and a part thereof is adjacent to the magnetic pole portion (19b). Projects radially inward from between. Preferably, the coil (20) is fixed to the core (19) by appropriate means such as an adhesive, and the spacing member (25) is fixed to the core (19) and the coil (20). The assembly procedure for making the stator unit material (4) is arbitrary.
[0060]
Next, the surface obtained by combining the inner surface (19c) of the magnetic pole part (19b) of the core (19) of the electromagnet (18 ) and the inner surface (25c) of the spacing member (25) by appropriate means such as grinding is shown in FIG. Machining the magnetic pole part (19b) of the core (19) of the stator unit material (4) and the radially inner part of the spacing member (25) so as to form one common cylindrical surface as shown by the chain line in FIG. The stator unit (3) as shown in FIGS. 1 to 3 is completed. The spacing member (25) whose inner surface (25c) has been processed into a cylindrical shape is left as it is in the stator unit (3).
[0061]
When the magnetic pole part (19b) of the core (19) is machined by grinding or the like as described above, a circumferential machining force acts on the magnetic pole part (19b), but there is a gap between the adjacent magnetic pole parts (19b). Since the holding body (25) is interposed and the magnetic pole part (19b) receives pressure in the circumferential direction by the spacing holding body (25), the tip of the magnetic plate (21) is deformed in the circumferential direction by the processing force. There is no such thing as to be distracted. For this reason, the inner surface of the magnetic pole part (19b) of the core (19) can be processed with high accuracy. Further, the remaining spacing holder (25) prevents rattling of the coil (20). Since the spacing member (25) is made of a non-magnetic material, it does not adversely affect the magnetic properties of the electromagnet (18) even if it is left as it is after processing.
[0062]
In the above embodiment, the processed spacing holder (25) remains in the stator unit (3) as it is, but the spacing holder may be removed from the stator unit after processing. In that case, the spacing member need not be made of a nonmagnetic material, and an appropriate material having good cutting properties, such as an aluminum alloy, can be used.
[0068]
The specific configuration of each part of the stator unit of the magnetic bearing is not limited to that of the above embodiment, and can be changed as appropriate.
[Brief description of the drawings]
FIG. 1 is a plan view of a stator assembly of the radial magnetic bearing illustrating an implementation form of the present invention.
FIG. 2 is a cross-sectional view taken along the line AB of FIG.
FIG. 3 is a cross-sectional view taken along line A-C of FIG.
FIG. 4 is a plan view of a stator unit material according to the first embodiment.
FIG. 5 is a perspective view showing a part of the stator unit material shown in FIG.
Figure 6 is a plan view of a stator unit material and the stator unit of the radial magnetic bearing shown the Supporting come example.
[Explanation of symbols]
(3) Stator unit
(4 ) Stator unit material
(10) Rotating body
(17) Stator housing
(18) Electromagnet
(19) Core
(19a) Connecting part
(19b) Magnetic pole part
(19c) Inside
(20) Coil
(21) Magnetic plate
(25) Core spacing holder
(25 c) in the plane

Claims (3)

A stator housing disposed around the rotating body and a plurality of electromagnets fixed to the stator housing at intervals in the circumferential direction, each of the electromagnets being laminated in the circumferential direction. And a core having a pair of magnetic pole portions protruding radially inward from both ends of the connecting portion extending in the axial direction and a coil wound around each magnetic pole portion of each electromagnet. A method of manufacturing a unit, comprising:
An electromagnet having a core in which a plurality of magnetic plates having the same shape are laminated is fixed to the stator housing, and a core spacing holder made of a prismatic nonmagnetic material between the magnetic pole portions of the electromagnet adjacent in the circumferential direction. Is a first step of making a stator unit material interposed in a state of being pressed against a radially inner facing surface of the magnetic pole portion and a surface facing the radially inner side of the coil ,
And a second step of processing the inner surface of the combined portion of the core of the stator unit material and the core spacing holder so as to become one common cylindrical surface. Method. A stator housing disposed around the rotating body and a plurality of electromagnets fixed to the stator housing at intervals in the circumferential direction, each of the electromagnets being laminated in the circumferential direction. And a core having a pair of magnetic pole portions protruding radially inward from both ends of the connecting portion extending in the axial direction and a coil wound around each magnetic pole portion of each electromagnet A method of manufacturing a unit, comprising:
Electromagnet having a core in which a plurality of magnetic plates having the same shape are laminated is fixed to the stator housing, between the magnetic pole portion of said electromagnet circumferentially adjacent, prismatic core distance holder is, the magnetic pole A first step of making a stator unit material interposed in a state in which the coil is in pressure contact with a facing surface radially inward of the coil and in contact with a surface facing radially inward of the coil ;
A second step of processing the inner surface of the combined portion of the stator unit material core and the core spacing holder so as to form one common cylindrical surface;
And the manufacturing method of the stator unit of the magnetic bearing characterized by including the 3rd process of removing the said core space | interval holding body. In the first step, a stator unit material in which one common core spacing member is interposed between magnetic pole portions at both ends of the core of the electromagnet adjacent in the circumferential direction is formed. Item 3. A method for manufacturing a stator unit of a magnetic bearing according to Item 1 or 2 .

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