JP4595531B2 - Magnetic bearing device - Google Patents

Description

  The present invention relates to a magnetic bearing device for rotating a rotating body in a non-contact manner by a magnetic bearing.

  As this type of magnetic bearing device, a rotating body is known that is supported in a non-contact manner by one set of control type axial magnetic bearings and two sets of control type radial magnetic bearings and is rotated at high speed by a built-in electric motor.

Normally, each radial magnetic bearing is provided with four electromagnets arranged around the rotating body at equal intervals in the circumferential direction, and an electromagnetic steel plate is provided on the outer peripheral portion of the rotating body facing these electromagnets. A core in which silicon steel plates are laminated in the axial direction is fixed. The core is formed by laminating an annular silicon steel sheet one by one on the outer periphery of the rotating body and then polishing the outer periphery (see, for example, Patent Document 1).
JP-A-11-13761

  The entire surface of the annular silicon steel sheet constituting the core as described above is coated with an inorganic insulating film, but the insulating film of the silicon steel sheet is destroyed by polishing the outer peripheral surface of the core, resulting in an insulating effect. As a result, the eddy current loss due to the electromagnet increases, and the temperature of the rotating body rises due to heat generation.

  An object of the present invention is to provide a magnetic bearing device capable of solving the above-described problems and suppressing the rotation loss and temperature rise of a rotating body.

A magnetic bearing device according to the present invention is a magnetic bearing device that supports a rotating body in a radial non-contact manner by a control type radial magnetic bearing, and has a plurality of circles on an outer peripheral portion of the rotating body facing an electromagnet constituting the radial magnetic bearing. In a structure in which a core on which an annular magnetic steel sheet is laminated is fixed, each magnetic steel sheet constituting the core is coated with an insulating coating on the surface, and the outer peripheral surface of the core is not subjected to polishing. Thus, the eddy current generated in the core portion of the rotating body facing the electromagnet constituting the magnetic bearing is reduced to suppress the rotation loss and the temperature rise of the rotating body. .

  Since the outer peripheral surface of the core is not polished, the insulating coating of the magnetic steel sheet constituting the core is not destroyed, and therefore the insulating effect is not diminished. For this reason, the eddy current generated in the core portion is small, and the temperature increase due to the rotation loss and heat generation of the rotating body is also small.

  The core may be formed by fitting electromagnetic steel sheets one by one to the outer peripheral portion of the rotating body. Further, a core may be formed by laminating a plurality of electromagnetic steel sheets, and this may be fitted to a rotating body. In the latter case, the dimensional accuracy of the outer diameter of the completed core can be increased by accurately laminating the electromagnetic steel sheets.

  According to the magnetic bearing device of the present invention, as described above, the eddy current generated in the core portion of the rotating body facing the electromagnet constituting the magnetic bearing is reduced to suppress the rotation loss and the temperature increase of the rotating body. can do

  Hereinafter, an embodiment in which the present invention is applied to a five-axis control type magnetic bearing device will be described with reference to the drawings.

  FIG. 1 shows a main part of the magnetic bearing device.

  This magnetic bearing is a horizontal type in which a horizontal rotating body (1) rotates inside a horizontal cylindrical housing (not shown), and the rotating body (1) is placed on the portion of the housing around the rotating body (1). Control type axial magnetic bearing (2) supporting non-contact in the axial direction, two sets of control type radial magnetic bearings (3) (4), rotating body (1) An axial displacement sensor (5) for detecting the axial displacement of the rotor, two sets of radial displacement sensors (6) (7) for detecting the radial displacement of the rotating body (1), and the rotating body (1) A stator (8) of the electric motor that rotates the motor, a rotation sensor (not shown) for detecting the rotational speed of the rotating body (1), a protective bearing for touchdown (not shown), and the like are arranged.

  Each radial magnetic bearing (3) (4) is provided with four electromagnets (9) (10). Each of the radial displacement sensors (6) and (7) is a set of four. On the outer periphery of the rotating body (1) facing the electromagnets (9) (10) of each set of radial magnetic bearings (3) (4) and the radial displacement sensors (6) (7) of each set, a core ( 11) (12) (13) (14) are provided.

  Since the configuration of the magnetic bearing device itself is known, further detailed description is omitted.

  The first core (11) and the second core (12) facing the electromagnets (3) and (4) are formed by laminating annular silicon steel plates (electromagnetic steel plates) (15) as shown in FIG. . The entire surface of each silicon steel plate (15) is coated with an inorganic insulating coating (16). Each core (11) (12) is formed into a cylindrical shape by laminating silicon steel plates (15), and then fitted to the outer peripheral portion of the rotating body (1) and fixed. The outer peripheral surfaces of the cores (11) and (12) are not subjected to conventional polishing.

  The third core (13) and the fourth core (14) facing the radial displacement sensors (6) and (7) are also formed by laminating an annular silicon steel plate (17) similar to the above. These cores (13) and (14) may be fixed to the outer periphery of the rotating body (1) after being formed into a cylindrical shape by laminating silicon steel plates (17). It may be formed by fitting silicon steel plates (17) one by one on the outer periphery of 1). In any case, after the cores (13) and (14) are formed on the outer peripheral portion of the rotating body (1), the outer peripheral portions of the cores (13) and (14) are polished.

  In the case of the above embodiment, the outer peripheral portion of the core (13) (14) facing the radial displacement sensor (6) (7) is subjected to polishing, and the dimensional accuracy of the outer diameter of the core (13) (14) Therefore, the radial displacement of the rotating body (1) can be detected with high accuracy.

  Also, since the outer peripheral surface of the core (11) (12) facing the electromagnet (9) (10) of the radial magnetic bearing (3) (4) is not polished, the core (11) (12) The insulating coating (16) of the silicon steel plate (15) that constitutes is not broken, and therefore the insulating effect is not diminished. For this reason, the eddy current generated in the cores (11) and (12) is small, and the temperature rise due to the rotation loss and heat generation of the rotating body (1) is also small.

  FIG. 3 is a graph showing the relationship between the rotational speed of the rotating body (1) and the rotational loss. In FIG. 3, A is a comparison in which the outer peripheral surfaces of the cores (11) and (12) are not polished, and B is a comparison in which the outer peripheral surfaces of the cores (11) and (12) are polished. An example case is shown. From FIG. 3, it can be seen that the above embodiment has a smaller rotation loss than the comparative example.

  Furthermore, in the above embodiment, after forming the cylindrical cores (11) and (12) by laminating the silicon steel plates (15), this is fixed to the outer periphery of the rotating body (1). When forming the core (11) (12), the silicon steel plate (15) is accurately laminated to increase the dimensional accuracy of the outer diameter of the core (11) (12) without polishing. Can do. However, these cores (11) and (12) may also be formed by fixing silicon steel plates (15) one by one to the outer peripheral portion of the rotating body (1).

  The overall configuration of the magnetic bearing device and the configuration of each part are not limited to those of the above-described embodiment, and can be changed as appropriate.

FIG. 1 is a schematic configuration diagram of a magnetic bearing device showing an embodiment of the present invention. FIG. 2 is a perspective view of a silicon steel plate constituting the core. FIG. 3 is a graph showing the relationship between the number of rotations of the rotating body and the rotation loss.

Explanation of symbols

(1) Rotating body
(3) (4) Radial magnetic bearing
(9) (10) Electromagnet
(11) (12) Core
(15) Silicon steel sheet
(16) Insulation coating

Claims (1)

A magnetic bearing device for supporting a rotating body in a radial non-contact manner by a control type radial magnetic bearing, wherein a plurality of annular electromagnetic steel plates are laminated on an outer peripheral portion of the rotating body facing an electromagnet constituting the radial magnetic bearing. In what the core is fixed,
Each of the electromagnetic steel sheets constituting the core is coated with an insulating coating on the surface, and the outer peripheral surface of the core is not subjected to polishing so that the core of the rotating body facing the electromagnet constituting the magnetic bearing A magnetic bearing device characterized in that an eddy current generated in a portion is reduced to suppress a rotation loss and a temperature rise of a rotating body .

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