JP2016118226A - Magnetic bearing and rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic bearing and a rotary machine capable of discharging heat in a gap between a disc and an electromagnet unit without supply of high-pressure cooling gas.SOLUTION: A magnetic bearing has a disc provided for a rotor, and an electromagnet unit disposed to face the disc, and the electromagnet unit comprises a coil and a core which contains the coil and has a radiation slit penetrating a range from a disc-side region facing the disc to a side opposite to the disc.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a magnetic bearing and a rotating machine.

  For example, as shown in Patent Document 1, in a rotary machine such as a turbo compressor and a motor, a magnetic bearing is used to support the rotor with as little rotational resistance as possible. In general, when a magnetic bearing is employed, a radial magnetic bearing that supports a load in the radial direction of the rotor and an axial magnetic bearing that supports a load in the axial direction of the rotor are provided as the magnetic bearing. .

JP 2001-214935 A

  By the way, in recent years, the rotation speed of the rotor has been increased, and the axial length of the rotor has been shortened from the viewpoint of improving the stability during rotation. Since the axial magnetic bearing is configured such that the disk fixed to the rotor is sandwiched from both sides by a certain gap with the electromagnet unit, the axial length of the rotor is shortened, so that the installation space for the electromagnet unit can be secured. It's getting harder. On the other hand, in order to ensure a constant magnetic flux in the electromagnet unit, it is necessary to maintain the coil line product ratio. For this reason, especially in rotating machines where the rotor rotates at high speeds, the electromagnet unit is expanded in the radial direction of the rotor, thereby maintaining the coil line area ratio and flattening in the axial direction of the rotor. It corresponds to.

  As the rotor becomes shorter, the gap between the disk and the electromagnet unit becomes narrower. The cooling gas is supplied to the gap between the disk and the electromagnet unit in order to exhaust the heat generated by the friction between the disk and the air. However, since the gap is narrow as described above, the cooling gas to be supplied is It is necessary to increase the pressure. However, when the pressure of the cooling gas is increased, the flow velocity in the gap increases and the windage loss in the disk increases. For this reason, the rotational resistance increases, and the power for rotationally driving the rotor increases. As a result, the efficiency of the rotating machine is deteriorated.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to enable exhaust heat in a gap between a disk and an electromagnet unit in a magnetic bearing and a rotary machine without supplying a high-pressure cooling gas. And

  The present invention adopts the following configuration as means for solving the above-described problems.

  1st invention is a magnetic bearing which has the disk provided with respect to the rotor, and the electromagnet unit arranged facing the said disk, Comprising: The said electromagnet unit contains a coil, the said coil, and the said disk A configuration is adopted in which a core that has a heat dissipating slit that penetrates from the region facing the disk on the side to the opposite side of the disk and allows fluid to pass through is employed.

  A second invention employs a configuration in which the end of the coil is disposed inside the heat dissipation slit in the first invention.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the heat dissipating slit is formed long in the radial direction of the rotor and provided in a plurality in the circumferential direction of the rotor.

  According to a fourth invention, in any one of the first to third inventions, the heat dissipating slit is a flow of air between the heat dissipating slit and the disk and an internal air flow when viewed from the radial direction of the rotor. A configuration is adopted in which the flow is provided to be inclined with respect to the axis of the rotor so that the flow approaches the same direction and parallel.

  According to a fifth invention, in any one of the first to fourth inventions, the heat dissipating slit has a width of an opening end on the disc side opposite to the disc when viewed from the radial direction of the rotor. A configuration that is wider than the width is adopted.

  6th invention is a rotary machine provided with a rotor and the magnetic bearing which supports the said rotor rotatably, Comprising: The structure provided with the magnetic bearing which is one of said 1st-5th invention as said magnetic bearing Is adopted.

  According to the present invention, the heat radiating slit penetrating from the area facing the disk on the disk side to the opposite side of the disk is provided for the core. Such a heat radiating slit is connected to a gap between the disk and the electromagnet unit where heat is easily generated. For this reason, it becomes possible to exhaust the heat in the gap between the disk and the electromagnet unit as compared with the case where no heat dissipation slit is formed. For this reason, according to the present invention, it is not necessary to supply the cooling gas at a high pressure, and the windage loss in the disk is not increased.

It is a longitudinal section showing a schematic structure of a motor in one embodiment of the present invention. It is the front view and back view of an electromagnet unit with which the motor in one embodiment of the present invention is provided, (a) is the front view seen from the disk side, (b) is the back view seen from the disk opposite side. . It is sectional drawing of the electromagnet unit with which the motor in one Embodiment of this invention is provided, (a) is the sectional view on the AA line of FIG. 2, (b) is the sectional view on the BB line of FIG. It is a principal part expanded sectional view containing a part of electromagnet unit with which the motor in one Embodiment of this invention is equipped, and a disk. It is a schematic diagram which shows the modification of the motor in one Embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a magnetic bearing and a rotary machine according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

  FIG. 1 is a longitudinal sectional view showing a schematic configuration of a motor 1 (rotary machine) of the present embodiment. As shown in this figure, the motor 1 of this embodiment is mounted on an air compressor, for example, and includes a housing 2, a stator 3, a rotor 4, a radial magnetic bearing 5, an axial magnetic bearing 6, and an auxiliary bearing 7. And a cooling gas supply device 8.

  The housing 2 is a casing that houses the stator 3, the rotor 4, the radial magnetic bearing 5, the axial magnetic bearing 6, and the auxiliary bearing 7. The housing 2 is provided with a through hole through which the rotor 4 passes in order to expose the tip of the rotor 4. The stator 3 is accommodated in the housing 2 and is supported by being fixed to the housing 2. The stator 3 includes a coil that is disposed so as to surround the rotor 4 at a predetermined interval, and a power supply state is controlled by a motor control device (not shown).

  The rotor 4 is a rod member whose posture is set so that the axial direction is horizontal, and a permanent magnet is provided at a position facing the stator 3. The rotor 4 is rotationally driven by a magnetic field generated by power feeding to the stator 3, and is rotatably supported by the radial magnetic bearing 5 and the axial magnetic bearing 6 at the time of rotation. The rotor 4 is supported by the auxiliary bearing 7 when stopped. The radial magnetic bearing 5 and the axial magnetic bearing 6 support the rotor 4 rotatably. The radial magnetic bearing 5 is provided for each end of the rotor 4. These radial magnetic bearings 5 generate magnetic force by being fed from a power feeding device (not shown), and support the load in the radial direction of the rotor 4 in a non-contact manner.

  As shown in FIG. 1, the axial magnetic bearing 6 includes a disk 6a and two electromagnet units 6b. The disk 6 a is a disk-shaped member made of a magnetic material and is provided for the rotor 4. The disk 6 a has a larger diameter than the rotor 4 and is fixed concentrically to the rotor 4. Such a disk 6 a has an outer edge protruding outside the rotor 4 when viewed from the axial direction of the rotor 4. The two electromagnet units 6b are disposed to face the disk 6a so as to sandwich the disk 6a from the axial direction of the rotor 4, and are opposed to the housing 2 so as to face the disk 6a with a slight gap. Is fixed. The axial magnetic bearing 6 generates a magnetic force by being fed from a power supply device (not shown), and supports the load in the axial direction of the rotor 4 in a non-contact manner.

  2A and 2B are a front view and a rear view of the electromagnet unit 6b, where FIG. 2A is a front view seen from the disk 6a side, and FIG. 2B is a rear view seen from the side opposite to the disk 6a. 3 is a cross-sectional view of the electromagnet unit 6b, (a) is a cross-sectional view taken along line AA in FIG. 2, and (b) is a cross-sectional view taken along line BB in FIG. FIG. 4 is an enlarged cross-sectional view of a main part including a part of the electromagnet unit 6b and the disk 6a. As shown in these drawings, the electromagnet unit 6b includes a coil 6b1 and a core 6b2.

  The coil 6b1 is formed by a winding wound around the rotor 4, and power is supplied by a power supply device (not shown). The coil 6b1 is wound with a winding so as to have a predetermined line product ratio. The core 6b2 is an annular member made of a magnetic material and having an opening through which the rotor 4 is inserted at the center, and includes the coil 6b1. The core 6b2 has an annular magnetic pole slit 6b3 and a radial heat dissipation slit 6b4 in a region Ra facing the disk 6a.

  The magnetic pole slit 6b3 is provided in an annular shape with the rotor 4 as the center, and is provided in a region where the coil 6b1 is included when viewed from the axial direction of the rotor 4, thereby exposing a part of the coil 6b1. By this magnetic pole slit 6b3, the disk 6a side of the core 6b2 is divided into an inner diameter side and an outer diameter side to form a magnetic pole.

  A plurality of the heat radiating slits 6 b 4 are provided radially around the axis of the rotor 4 when viewed from the axial direction of the rotor 4. That is, each heat radiation slit 6 b 4 is formed long in the radial direction of the rotor 4, and a plurality of the heat dissipation slits 6 b 4 are provided in the circumferential direction of the rotor 4. Such a heat radiating slit 6b4 is provided so as to penetrate from the region Ra facing the disk 6a on the disk 6a side to the opposite side of the disk 6a, and is capable of penetrating fluid (cooling gas).

  Further, as shown in FIG. 4, the heat radiating slit 6b4 has a length set such that the end position on the outer side in the radial direction of the rotor 4 is positioned on the inner side in the radial direction of the rotor 4 with respect to the peripheral surface 6a1 of the disk 6a. ing. As a result, the narrow portion 6c is formed between the core 6b2 and the disk 6a even at the location where the heat dissipation slit 6b4 is formed. If the end position of the heat radiating slit 6b4 is located on the outer side in the radial direction of the rotor 4 relative to the peripheral surface 6a1 of the disk 6a, the narrowed portion 6c is not provided and protrudes to the outer side in the radial direction of the disk 6a. The cooling gas easily flows through the end portion of the heat radiating slit 6b4, and the cooling gas does not easily flow into the gap between the disk 6a and the core 6b2. On the other hand, when the narrow portion 6c is provided, the cooling gas can surely flow into the gap between the disk 6a and the core 6b2.

  The coil 6b1 is molded by a resin mold 6b5, and is fixed so that the end position 6b6 on the radially inner side of the rotor 4 is disposed inside the heat dissipation slit 6b4. As a result, a part of the coil 6b1 is placed in the heat dissipation slit 6b4 serving as a cooling gas flow path in a state where the coil 6b1 is partially molded in the resin mold 6b5.

  Note that the magnetic pole slit 6b3 and the heat radiation slit 6b4 can be easily formed by discharge wire processing. In addition, the resin 6 is injected into the core 6b2 while the coil 6b1 is included in the core 6b2 in which the magnetic pole slit 6b3 and the heat radiation slit 6b4 are formed, and a baffle plate or the like is inserted into the magnetic pole slit 6b3 and the heat radiation slit 6b4. Thus, it is possible to easily form the electromagnet unit 6b in which the magnetic pole slit 6b3 and the heat dissipating slit 6b4 are voids.

  A plurality of heat radiation slits 6b4 are provided radially. For this reason, the area Ra facing the disk 6 a on the disk 6 a side of the core 6 b 2 is divided into a plurality of areas in the circumferential direction of the rotor 4 by the heat radiating slit 6 b 4.

  Returning to FIG. 1, the auxiliary bearing 7 is provided corresponding to each of both ends of the rotor 4, and is fixed to the housing 2. These auxiliary bearings 7 are provided so that a slight gap is left with respect to the rotor 4 when the rotor 4 is pivotally supported by the radial magnetic bearing 5 and the axial magnetic bearing 6. Such an auxiliary bearing 7 supports the rotor 4 in a state where the rotation of the rotor 4 is stopped and power supply to the radial magnetic bearing 5 and the axial magnetic bearing 6 is stopped. Further, the rotor 4 is pivotally supported when the rotor 4 rotating due to some influence in the event of an emergency such as a power failure or earthquake deviates from the original reference position.

  The cooling gas supply device 8 is connected to a cooling gas introduction hole 2a provided in the housing 2, and the cooling gas is introduced into the space between the two electromagnet units 6b inside the housing 2 through the cooling gas introduction hole 2a. Supply X. As shown in FIG. 4, the cooling gas X supplied in this way flows into the gap between the disk 6a and the electromagnet unit 6b through the narrow portion 6c, and partly passes through the electromagnet unit 6b through the heat dissipation slit 6b4. The remainder passes through the electromagnet unit 6b through the gap between the rotor 4 and the electromagnet unit 6b. The cooling gas X that has passed through the electromagnet unit 6b in this manner flows out of the housing 2 through a gap between the auxiliary bearing 7 and the rotor 4 shown in FIG.

  In the motor 1 of this embodiment having such a configuration, the rotor 4 is rotationally driven by supplying power to the stator 3, and further, the rotor 4 is supplied by supplying power to the radial magnetic bearing 5 and the axial magnetic bearing 6. Is supported in a non-contact manner. For this reason, the rotor 4 can be rotated in a state where the rotational resistance is extremely small.

  According to the motor 1 of the present embodiment as described above, the heat radiation slit 6b4 penetrating from the area Ra facing the disk 6a on the disk 6a side to the opposite side of the disk 6a is provided for the core 6b2. Such a heat radiating slit 6b4 is connected to a gap between the disk 6a and the electromagnet unit 6b where heat is easily generated. For this reason, it is possible to exhaust heat in the gap between the disk 6a and the electromagnet unit 6b as compared with the case where the heat dissipation slit 6b4 is not formed. For this reason, according to the motor 1 of this embodiment, it is not necessary to supply the cooling gas X at a high pressure, and the windage loss in the disk 6a is not increased.

  Moreover, in the motor 1 of this embodiment, the edge part of the coil 6b1 is arrange | positioned inside the thermal radiation slit 6b4. For this reason, a part of the coil 6b1 is directly cooled by the cooling gas X passing through the heat radiation slit 6b4, whereby the cooling efficiency of the coil 6b1 can be increased.

  Further, in the motor 1 of the present embodiment, the heat radiating slit 6 b 4 is formed long in the radial direction of the rotor 4, and a plurality of the heat radiating slits 6 b 4 are provided in the circumferential direction of the rotor 4. For this reason, the area Ra facing the disk 6a on the disk 6a side of the core 6b2 is divided into a plurality of areas by the heat radiating slit 6b4 in the circumferential direction of the rotor 4, and the generation of a large eddy current in the area Ra is suppressed. Thereby, the eddy current loss in the electromagnet unit 6b can be reduced, and the frequency characteristic of the magnetic permeability of the electromagnet unit 6b can be improved.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

  For example, in the said embodiment, the structure which the cooling gas X flows into the clearance gap between the disk 6a and the electromagnet unit 6b through the narrow part 6c between the electromagnet units 6b was employ | adopted. However, the present invention is not limited to this, and the flow of the cooling gas X can be reversed.

  Moreover, in the said embodiment, seeing from the radial direction of the rotor 4, the structure where the thermal radiation slit 6b4 penetrated the core 6b2 in parallel with the axis | shaft of the rotor 4 was demonstrated. However, the present invention is not limited to this. As shown in FIG. 5A, the heat dissipating slit 6b4 is disposed in the rotor so that the air flow between the electromagnet unit 6b and the disk 6a and the air flow flowing inside the heat dissipating slit 6b4 approach in the same direction and in parallel. You may penetrate so that it may incline with respect to 4 axis | shafts. In the present embodiment, since air flows from the disk 6a side to the heat radiating slit 6b4, the opening end on the inlet side of the heat radiating slit 6b4 is positioned upstream in the rotation direction of the disk 6a, and the opening end on the outlet side of the heat radiating slit 6b4. The heat dissipating slit 6b4 is inclined so that is positioned downstream in the rotational direction of the disk 6a. When the flow direction of the cooling gas X is opposite to that of the above embodiment, the opening end on the outlet side of the heat radiating slit 6b4 is located on the upstream side in the rotation direction of the disk 6a, and on the inlet side of the heat radiating slit 6b4. The heat dissipating slit 6b4 is inclined so that the open end is located downstream in the rotational direction of the disk 6a.

  Moreover, in the said embodiment, seeing from the radial direction of the rotor 4, the structure where the width | variety of the opening end of the entrance side of the radiation | emission slit 6b4 and the width | variety of the opening end of the exit side of the radiation | emission slit 6b4 were the same was demonstrated. . However, the present invention is not limited to this, and as shown in FIG. 5B, the width of the opening end of the heat radiating slit 6b4 on the disk 6a side is larger than the width of the opening end on the side opposite to the disk 6a. It can also be widened. As a result, the opening area of the heat dissipating slit 6b4 on the side of the disk 6a serving as a heat generating portion is widened, and the heat dissipating effect is enhanced. .

  Moreover, in the said embodiment, the example which applied this invention to the magnetic bearing which has the flat electromagnet unit 6b was demonstrated. However, the present invention is not limited to this, and can be applied to a magnetic bearing having an electromagnet unit having another shape.

  Moreover, although the said embodiment demonstrated the example which applied this invention to the motor, this invention is not limited to this. For example, the present invention can be suitably applied to a rotating machine in which the natural frequency of the rotor is a major factor in determining characteristics, or a rotating machine that requires a predetermined suction force in a limited space. . Examples of such rotating machines include air compressors, turbo chillers, air separators, and gas turbines.

  DESCRIPTION OF SYMBOLS 1 ... Motor (rotary machine), 2 ... Housing, 2a ... Cooling gas introduction hole, 2b ... Electromagnet unit, 3 ... Stator, 4 ... Rotor, 5 ... Radial magnetic bearing, 6 ... Axial magnetism Bearing, 6a... Disk, 6a1 ... peripheral surface, 6b ... electromagnet unit, 6b1 ... coil, 6b2 ... core, 6b3 ... magnetic pole slit, 6b4 ... heat radiation slit, 6b5 ... resin mold, 6b6 ... End position, 6c ... Narrow part, 7 ... Auxiliary bearing, 8 ... Cooling gas supply device, Ra ... Region, X ... Cooling gas

Claims (6)

A magnetic bearing having a disk provided for the rotor and an electromagnet unit disposed opposite to the disk,
The electromagnet unit is
Coils,
A magnetic bearing comprising: a core that includes the coil, and has a heat-dissipating slit penetrating from a region facing the disk on the disk side to the opposite side of the disk and allowing fluid to pass therethrough.   The magnetic bearing according to claim 1, wherein an end portion of the coil is disposed inside the heat dissipation slit.   3. The magnetic bearing according to claim 1, wherein the heat dissipating slit is formed long in a radial direction of the rotor, and a plurality of the heat dissipating slits are provided in a circumferential direction of the rotor.   The heat dissipating slit is viewed from the radial direction of the rotor, so that the air flow between the heat dissipating slit and the disk and the internal air flow approach the same direction and parallel to the axis of the rotor. The magnetic bearing according to claim 1, wherein the magnetic bearing is inclined.   The width of the opening end on the disk side is wider than the width of the opening end on the side opposite to the disk as viewed from the radial direction of the rotor. The magnetic bearing as described in. A rotary machine comprising a rotor and a magnetic bearing that rotatably supports the rotor,
A rotary machine comprising the magnetic bearing according to any one of claims 1 to 5 as the magnetic bearing.

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