Eddy current damper device and rotating machine

Abstract

To provide a compact eddy current damper device that also has the function of supporting a rotating body. [Solution] The eddy current damper device 1 comprises a bearing 5 for rotatably supporting a rotating body 2, a cylindrical body 7 that holds the bearing 5, a conductive plate 10 that protrudes radially outward from the outer circumferential surface of the cylindrical body 2, magnets 14 and 15 arranged adjacent to the side surface of the conductive plate 10 in the axial direction of the cylindrical body 7, and a yoke 20 that surrounds the conductive plate 10 and the magnets 14 and 15. The outer end face 10c of the conductive plate 10 is in contact with and held by the yoke 20. The conductive plate 10 has slits 31, 32, 33, and 34 that impart elasticity to the conductive plate 10, and the slits 31, 32, 33, and 34 extend around the entire circumference of the conductive plate 10.

Description

Technical Field

[0001] The present invention relates to an eddy current damper device for suppressing vibration of a rotating body, and particularly to an eddy current damper device that attenuates the vibration of the rotating body by generating eddy currents in a conductor when the rotating body vibrates. Further, the present invention relates to a rotating machine provided with such an eddy current damper device.

Background Art

[0002] An eddy current damper is a vibration damping device that attenuates the vibration of a rotating body by generating eddy currents in a conductor when the rotating body vibrates. A conventional eddy current damper does not itself have a function of supporting the rotating body, and is configured to support the rotating body by a support member separate from the eddy current damper. For example, Patent Document 1 discloses a support rod (see reference numeral 6) for supporting a rotating shaft. However, such a support member requires an installation location, and the structural elements associated with the installation of the eddy current damper increase. Further, the installation of such a support member may limit the application range of the eddy current damper.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, the present invention provides a compact eddy current damper device having a function of supporting a rotating body. Further, the present invention provides a rotating machine provided with such an eddy current damper device.

Means for Solving the Problems

[0005] In one embodiment, an eddy current damper device for suppressing vibration of a rotating body is provided, comprising: a bearing for rotatably supporting the rotating body; a cylindrical body holding the bearing; a conductive plate protruding radially outward from the outer circumferential surface of the cylindrical body; a magnet positioned adjacent to the side surface of the conductive plate in the axial direction of the cylindrical body; and a yoke surrounding the conductive plate and the magnet, wherein the outer end surface of the conductive plate is in contact with and held by the yoke, and the conductive plate has a slit that imparts elasticity to the conductive plate, the slit extending around the entire circumference of the conductive plate.

[0006] In one embodiment, the slit includes multiple arc-shaped slits extending around the entire circumference of the conductor plate. In one embodiment, the multiple circular arc slits include a plurality of semicircular arc slits with different radii of curvature. In one embodiment, the slit includes a helical slit extending around the entire circumference of the conductor plate.

[0007] In one embodiment, a rotating machine is provided, comprising a rotating shaft, an impeller or turbine fixed to the rotating shaft, an electric motor for rotating the rotating shaft, and the eddy current damper device for rotatably supporting the rotating shaft. In one embodiment, the rotating machine is a pumping device for transferring liquefied gas. [Effects of the Invention]

[0008] The conductor plate with slits is itself elastic in the radial and axial directions and has the function of centering the rotating body held in the bearing. The conductor plate is held in the yoke and can elastically support the bearing. Therefore, the eddy current damper device can not only dampen vibrations of the rotating body rotatably supported in the bearing, but can also rotatably support the rotating body. As a result, a compact eddy current damper device can be realized. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional perspective view showing one embodiment of an eddy current damper device. [Figure 2] This is a view of the conductor plate from its axial direction. [Figure 3] This figure shows another embodiment of the conductor plate. [Figure 4] This is a diagram illustrating the vibration damping principle of an eddy current damper device. [Figure 5] This figure shows another embodiment of the eddy current damper device. [Figure 6] This figure shows yet another embodiment of the eddy current damper device. [Figure 7] This figure shows yet another embodiment of the eddy current damper device. [Figure 8] This figure shows yet another embodiment of the eddy current damper device. [Figure 9] This figure shows yet another embodiment of the eddy current damper device. [Figure 10] This figure shows yet another embodiment of the eddy current damper device. [Figure 11] This figure shows yet another embodiment of the eddy current damper device. [Figure 12] This figure shows yet another embodiment of the eddy current damper device. [Figure 13] This figure shows yet another embodiment of the eddy current damper device. [Figure 14] This graph shows experimental results investigating the damping of radial and axial vibrations of a rotating body supported by the eddy current damper device of the embodiment shown in Figure 7. [Figure 15] This is a cross-sectional view showing one embodiment of a rotating machine equipped with an eddy current damper device. [Figure 16] This is a cross-sectional view showing another embodiment of a rotating machine equipped with an eddy current damper device. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional perspective view showing an embodiment of an eddy current damper device. The eddy current damper device 1 is a vibration damping device for suppressing the vibration of the rotating body 2. As shown in FIG. 1, the eddy current damper device 1 of the present embodiment includes a bearing 5 for rotatably supporting the rotating body 2, a cylindrical body 7 for holding the bearing 5, a conductor plate 10 protruding radially outward from the outer peripheral surface of the cylindrical body 7, magnets 14 and 15 disposed adjacent to the side surface of the conductor plate 10 in the axial direction of the cylindrical body 7, and a yoke 20 surrounding the conductor plate 10 and the magnets 14 and 15. The conductor plate 10 is in contact with the yoke 20 and is held by the yoke 20.

[0011] In one example, the rotating body 2 is a rotating shaft of a rotating machine such as a pump device, a blower, a turbo rotary machine, or a turbine power generation device. Examples of the bearing 5 for rotatably supporting the rotating body 2 include rolling bearings such as ball bearings and roller bearings. In the embodiment shown in FIG. 1, two bearings 5 are arranged in parallel. In other embodiments, only one bearing 5 or three or more bearings 5 may be provided.

[0012] The cylindrical body 7 is a bearing holding portion having a cylindrical shape. The cylindrical body 7 is made of a conductive material such as aluminum or stainless steel. The bearing 5 is held by the cylindrical body 7. More specifically, the bearing 5 is fitted into the cylindrical body 7, and the outer peripheral surface of the bearing 5 is held by the inner peripheral surface of the cylindrical body 7.

[0013] The conductor plate 10 is made of a conductive material such as aluminum or stainless steel. In particular, aluminum has high electrical conductivity in a cryogenic environment, so it is suitable when the eddy current damper device 1 is used in a cryogenic environment. The conductor plate 10 is connected to the outer peripheral surface of the cylindrical body 7. In the present embodiment, the conductor plate 10 and the cylindrical body 7 form an integral structure.

[0014] In the embodiment shown in Figure 1, the yoke 20 has a cylindrical inner circumferential surface 20a, and the conductor plate 10 is a circular conductor disc that contacts the inner circumferential surface 20a of the yoke 20. However, the shape of the conductor plate 10 may be appropriately changed according to the shape of the yoke 20. On the other hand, a circular conductor plate 10 is preferred from the viewpoint of having uniform mechanical rigidity in its circumferential direction.

[0015] The two magnets 14 and 15 are positioned on both sides of the conductor plate 10. In this embodiment, these magnets 14 and 15 are annular permanent magnets. Examples of permanent magnets include samarium-cobalt magnets and neodymium magnets. In particular, samarium-cobalt magnets have low temperature dependence and can be used over a wide temperature range, making them suitable for applications where the eddy current damper device 1 is used in cryogenic environments.

[0016] The magnets 14 and 15 are fixed to the yoke 20. The two magnets 14 and 15 are arranged around the cylindrical body 7 and extend around the entire circumference of the conductive plate 10. The two magnets 14 and 15 are not in contact with the cylindrical body 7 and the conductive plate 10. That is, there is a gap between the inner surfaces of the two magnets 14 and 15 and the outer surface of the cylindrical body 7, and there is a gap between the inner surfaces 14a and 15a of the two magnets 14 and 15 and the two sides 10a and 10b of the conductive plate 10.

[0017] One of the two magnets 14 and 15 faces one side 10a of the conductor plate 10, and the other of the two magnets 14 and 15 faces the opposite side 10b of the conductor plate 10. The two magnets 14 and 15 have inner surfaces 14a and 15a that face both sides 10a and 10b of the conductor plate 10, respectively, and these inner surfaces 14a and 15a of the two magnets 14 and 15 have opposite magnetic poles. In the embodiment shown in Figure 1, the inner surface 14a of magnet 14 has a north pole, and the inner surface 15a of the other magnet 15 has a south pole. In other embodiments, the inner surface 14a of magnet 14 may have a south pole, and the inner surface 15a of the other magnet 15 may have a north pole. The inner surface 14a and outer surface 14b of magnet 14 have opposite magnetic poles, and the inner surface 15a and outer surface 15b of the other magnet 15 also have opposite magnetic poles.

[0018] The yoke 20 is made of a magnetic material such as electromagnetic soft iron. The yoke 20 has two wall portions 24 and 25 that contact the outer surfaces 14b and 15b of the two magnets 14 and 15, respectively. These wall portions 24 and 25 have an annular shape that protrudes radially inward toward the outer circumferential surface of the cylindrical body 7. The conductor plate 10 and the two magnets 14 and 15 are positioned between the two wall portions 24 and 25. The outer end face 10c (the outer end face in the radial direction, the outer circumferential surface) of the conductor plate 10 is in contact with the inner circumferential surface 20a of the yoke 20 and is held by the yoke 20. Therefore, the relative position between the outer end face 10c of the conductor plate 10 and the yoke 20 is fixed.

[0019] A bearing 5 is present between the rotating body 2 and the cylindrical body 7. Therefore, the cylindrical body 7, the conductive plate 10, the magnets 14 and 15, and the yoke 20 are non-rotating elements.

[0020] Figure 2 is a view of the conductor plate 10 from its axial direction. The conductor plate 10 has a plurality of slits 31, 32, 33, and 34 that impart elasticity to the conductor plate 10. The slits 31, 32, 33, and 34 as a whole extend around the entire circumference of the conductor plate 10. The slits 31, 32, 33, and 34 are multiple arc-shaped slits that extend around the entire circumference of the conductor plate 10. The slits 31, 32, 33, and 34 are arranged at equal intervals around the center of the conductor plate 10.

[0021] Each of the slits 31, 32, 33, and 34 has a semicircular shape. More specifically, slit 31 has an outer arc slit 31A and an inner arc slit 31B that extend in the circumferential direction of the conductor plate 10, and a connecting slit 31C that connects the outer arc slit 31A and the inner arc slit 31B. The radius of curvature of the outer arc slit 31A is greater than the radius of curvature of the inner arc slit 31B. The connecting slit 31C extends diagonally from the end of the outer arc slit 31A to the end of the inner arc slit 31B. Slits 32, 33, and 34 have the same shape and size as slit 31. Each of the slits 31, 32, 33, and 34 has the same width.

[0022] In other embodiments, the conductor plate 10 may further have a plurality of arcuate slits radially outward or radially inward of the slits 31, 32, 33, 34. In yet another embodiment, the conductor plate 10 has four arcuate slits 31, 32, 33, 34, but in other embodiments, it may have two or three arcuate slits, or five or more arcuate slits.

[0023] These multiple arc-shaped slits 31, 32, 33, and 34 can impart radial and axial elasticity to the metal conductive plate (conductive disk) 10. Therefore, the conductive plate 10 can support the rotating body 2 via the bearing 5 while allowing vibration (translational motion) of the rotating body 2 supported by the bearing 5. The elasticity of the conductive plate 10 depends on the width of the slits 31, 32, 33, and 34. Therefore, the widths of the slits 31, 32, 33, and 34 are determined so that the conductive plate 10 has the desired elasticity.

[0024] Figure 3 shows another embodiment of the conductor plate 10. As shown in Figure 3, in this embodiment, the conductor plate 10 has a spiral slit 35 that extends around the entire circumference of the conductor plate 10.

[0025] The conductive plate 10, having multiple arcuate slits 31, 32, 33, 34 or helical slits 35, is itself elastic in the radial and axial directions and has the function of centering the rotating body 2 held by the bearing 5. The conductive plate 10 is held by the yoke 20 and can elastically support the bearing 5. Therefore, the eddy current damper device 1 can not only dampen the vibration of the rotating body 2 rotatably supported by the bearing 5, but can also rotatably support the rotating body 2. As a result, a compact eddy current damper device 1 can be realized.

[0026] Figure 4 illustrates the vibration damping principle of the eddy current damper device 1. As shown in Figure 4, a magnetic circuit M1 is generated extending within the magnets 14, 15, the conductive plate 10, and the yoke 20. As the rotating body 2 vibrates, the bearing 5, the cylindrical body 7, and the conductive plate 10 move in translation as a whole, but the magnets 14, 15 and the yoke 20 do not move in translation. This is because the cylindrical body 7 and the conductive plate 10 are not in contact with the magnets 14, 15, and the yoke 20. When the conductive plate 10 moves, a change in magnetic flux density occurs near the conductive plate 10 according to Lenz's law, and as a result, eddy currents are generated in the conductive plate 10. These eddy currents generate a damping force (resistance force) proportional to the speed of movement of the conductive plate 10.

[0027] When the conductor plate 10 moves radially, the density of magnetic flux passing through the conductor plate 10 in the axial direction changes, and eddy currents are generated in accordance with this change in magnetic flux density. These eddy currents generate a damping force (resistance force) that dampens the axial movement of the conductor plate 10. When the conductor plate 10 moves axially, the magnetic flux density in the conductor plate 10 changes according to the change in the distance between the conductor plate 10 and the magnets 14 and 15, and eddy currents are generated in accordance with this change in magnetic flux density. These eddy currents generate a damping force (resistance force) that dampens the radial movement of the conductor plate 10. In this way, the radial and axial movements of the conductor plate 10 are dampened by the damping force generated by the eddy currents.

[0028] Figure 5 shows another embodiment of the eddy current damper device 1. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment described with reference to Figures 1 to 4, so redundant descriptions are omitted. In addition to the magnets 14 and 15 described above, the eddy current damper device 1 of this embodiment further includes two auxiliary magnets 41 and 42 positioned outside the magnets 14 and 15 in the axial direction. These auxiliary magnets 41 and 42 are fixed to the walls 24 and 25 of the yoke 20.

[0029] The auxiliary magnets 41 and 42 are annular permanent magnets. The auxiliary magnets 41 and 42 are arranged around the cylindrical body 7 and extend along the outer surface of the cylindrical body 7. The auxiliary magnets 41 and 42 are not in contact with the cylindrical body 7 and the conductive plate 10. That is, there is a gap between the inner surfaces of the two auxiliary magnets 41 and 42 and the outer surface of the cylindrical body 7, and magnets 14 and 15 are present between the two auxiliary magnets 41 and 42 and the conductive plate 10.

[0030] The two auxiliary magnets 41 and 42 are positioned on either side of the two main magnets 14 and 15. The two auxiliary magnets 41 and 42 have inner surfaces 41a and 42a facing the outer surface of the cylindrical body 7, and these inner surfaces 41a and 42a of the two auxiliary magnets 41 and 42 have opposite magnetic poles. In the embodiment shown in Figure 5, the inner surface 41a of auxiliary magnet 41 has a south pole, and the inner surface 42a of the other auxiliary magnet 42 has a north pole. In other embodiments, the inner surface 41a of auxiliary magnet 41 may have a north pole, and the inner surface 42a of the other auxiliary magnet 42 may have a south pole. The inner surface 41a and outer surface 41b of auxiliary magnet 41 have opposite magnetic poles, and the inner surface 42a and outer surface 42b of the other auxiliary magnet 42 also have opposite magnetic poles.

[0031] As shown in Figure 5, a magnetic circuit M1 is generated extending through the magnets 14, 15, the conductor plate 10, and the yoke 20, and a magnetic circuit M2 is generated extending through the magnets 14, 15, auxiliary magnets 41, 42, the conductor plate 10, the cylindrical body 7, and the yoke 20. When the conductor plate 10 moves radially, the density of the magnetic flux passing through the conductor plate 10 in the axial direction changes, and eddy currents are generated in accordance with this change in magnetic flux density. These eddy currents generate a damping force (resistance force) that dampens the axial movement of the conductor plate 10. When the conductor plate 10 moves axially, the density of the magnetic flux in the conductor plate 10 and the cylindrical body 7 changes according to the change in the distance between the conductor plate 10 and the magnets 14, 15, and eddy currents are generated in accordance with this change in magnetic flux density. These eddy currents generate a damping force (resistance force) that dampens the radial movement of the conductor plate 10 and the cylindrical body 7. In this way, the radial and axial movement of the conductor plate 10 is dampened by the damping force generated by the eddy currents.

[0032] In the embodiments described with reference to Figures 1 to 5, one set of conductor plates 10 and a plurality of magnets 14, 15 are provided, but as shown in Figures 6 and 7, multiple sets of conductor plates 10 and a plurality of magnets 14, 15 may be provided. Figure 6 is a diagram showing one embodiment of the eddy current damper device 1 comprising two conductor plates 10 and four magnets 14, 15, and Figure 7 is a diagram showing one embodiment of the eddy current damper device 1 comprising two conductor plates 10, two magnets 14, 15, and two auxiliary magnets 41, 42. In the embodiments shown in Figures 6 and 7, the arrangement of the magnetic poles of the two sets of magnets 14, 15 is symmetrical with respect to the wall portion 25 of the yoke 20 located between these two sets.

[0033] In the embodiment shown in Figure 6, two conductor plates 10 are arranged in parallel along the axial direction of the cylindrical body 7, and two magnets 14 and 15 are positioned on both sides of each conductor plate 10. The magnets 14 and 15 are fixed to the walls 24, 25, and 26 of the yoke 20. In other embodiments, three or more sets of conductor plates 10 and multiple magnets 14 and 15 may be provided.

[0034] In the embodiment shown in Figure 7, two conductor plates 10 are arranged in parallel along the axial direction of the cylindrical body 7, with two magnets 14 and 15 positioned on both sides of each conductor plate 10, and two auxiliary magnets 41 and 42 positioned on both sides of the two magnets 14 and 15 positioned on both sides of each conductor plate 10. The magnets 14 and 15 and the auxiliary magnets 41 and 42 are fixed to the walls 24, 25, and 26 of the yoke 20. In other embodiments, three or more sets of conductor plates 10, multiple magnets 14 and 15, and auxiliary magnets 41 and 42 may be provided.

[0035] Figure 8 shows yet another embodiment of the eddy current damper device 1. In this embodiment, each of the magnets 14 and 15 is a Halbach array of permanent magnets configured such that the magnetic flux density is higher on the conductor plate 10 side. The Halbach array of permanent magnets is stacked along the radial direction of the conductor plate 10. The number of Halbach array permanent magnets constituting each of the magnets 14 and 15 is not limited to the embodiment shown in Figure 8.

[0036] Figure 9 shows an embodiment in which the auxiliary magnets 41 and 42 described above are combined with the multiple permanent magnets in the Halbach arrangement shown in Figure 8. The auxiliary magnets 41 and 42 are respectively positioned on the outside of the magnets 14 and 15, which are composed of multiple permanent magnets in the Halbach arrangement. The auxiliary magnet 41 and the innermost permanent magnet among the multiple permanent magnets that make up magnet 14 form a Halbach arrangement. Similarly, the auxiliary magnet 42 and the innermost permanent magnet among the multiple permanent magnets that make up magnet 15 form a Halbach arrangement. According to this embodiment, the magnetic flux density is higher on the cylindrical body 7 side.

[0037] Figure 10 shows yet another embodiment of the eddy current damper device 1. The embodiment shown in Figure 10 comprises multiple sets of magnets 14, 15 composed of multiple permanent magnets in a Halbach array and a conductive plate 10. Figure 11 shows yet another embodiment of the eddy current damper device 1. The embodiment shown in Figure 11 comprises multiple sets of magnets 14, 15 composed of multiple permanent magnets in a Halbach array, a conductive plate 10 and auxiliary magnets 41, 42. In the embodiments shown in Figures 10 and 11, the arrangement of the magnetic poles of the two sets of magnets 14, 15 is symmetrical with respect to the wall portion 25 of the yoke 20 located between these two sets.

[0038] Figure 12 shows yet another embodiment of the eddy current damper device 1. In this embodiment, electromagnets 51 and 52 are used as magnets positioned on both sides of the conductor plate 10. The electromagnets 51 and 52 have sides 51a and 52a that face each other on both sides of the conductor plate 10. The electromagnets 51 and 52 are electrically connected to a power cable (not shown) and generate a magnetic force when power is supplied.

[0039] Similar to the embodiment shown in Figure 4, a magnetic circuit M1 is generated extending through the electromagnets 51, 52, the conductor plate 10, and the yoke 20. When the conductor plate 10 moves, a change in magnetic flux density occurs near the conductor plate 10 according to Lenz's law, resulting in the generation of eddy currents in the conductor plate 10. These eddy currents generate a damping force (resistance force) proportional to the speed of movement of the conductor plate 10.

[0040] In yet another embodiment, as shown in Figure 13, the eddy current damper device 1 may include a combination of electromagnets 51, 52 and auxiliary magnets 41, 42. Embodiments described with reference to Figures 6 and 7, although not shown, can be applied to the embodiments of Figures 12 and 13.

[0041] Figure 14 is a graph showing experimental results investigating the damping of radial and axial vibrations of a rotating body 2 supported by the eddy current damper device 1 of the embodiment shown in Figure 7. This experiment was conducted under room temperature conditions and cryogenic conditions (-190°C). The material of the conductive plate 10 was aluminum (A1070). As can be seen from the experimental results shown in Figure 14, the rotating body 2 vibrates radially and axially, but its vibrations gradually decrease over time. These experimental results indicate that the eddy current damper device 1 can dampen the vibrations of the rotating body 2 while elastically supporting it.

[0042] The arc slits 31, 32, 33, and 34 shown in Figure 2 and the helical slit 35 shown in Figure 3 allow fluids such as liquids and air to pass through. Therefore, the fluid can cool the eddy current damper device 1. In particular, the cryogenic liquefied gas described below can cool the eddy current damper device 1 and improve its damping performance by increasing its conductivity.

[0043] Figure 15 is a cross-sectional view showing one embodiment of a rotating machine equipped with an eddy current damper device 1. The rotating machine in the embodiment shown in Figure 15 is a pump device for transferring liquids. In particular, the pump device shown in Figure 15 has a structure suitable for transferring liquefied gases. Examples of liquefied gases include liquid hydrogen, liquid helium, liquid methane, liquefied natural gas, liquefied ammonia, liquid nitrogen, liquefied ethylene gas, and liquefied petroleum gas.

[0044] The pump system comprises a pump 110, an electric motor 111 for rotating the pump 110, and eddy current damper devices 1A, 1B, 1C, one of the embodiments described with reference to Figures 1 to 13. In one embodiment, during operation of the pump 110, the electric motor 111 and the entire pump 110 are immersed in liquefied gas. Therefore, the electric motor 111 is a wet motor, and the pump 110 is a submersible pump capable of operating in liquefied gas.

[0045] The pump 110 has a pump-side rotating shaft 120, a plurality of impellers 125 fixed to the pump-side rotating shaft 120, and a pump casing 126 housing the plurality of impellers 125. In one embodiment, the pump 110 may have a single impeller 125. The eddy current damper device 1A rotatably supports the end of the pump-side rotating shaft 120. The eddy current damper devices 1B and 1C rotatably support the motor-side rotating shaft 122 of the electric motor 111. The eddy current damper devices 1B and 1C are located on both sides of the electric motor 111 in the axial direction. More specifically, the eddy current damper device 1B is located between the pump 110 and the electric motor 111, and the eddy current damper device 1C rotatably supports the end of the motor-side rotating shaft 122.

[0046] The electric motor 111 comprises a motor-side rotating shaft 122, a motor rotor 131 having multiple permanent magnets, and a motor stator 132 for generating a rotating magnetic field. The motor rotor 131 is fixed to the motor-side rotating shaft 122 and rotates integrally with the motor-side rotating shaft 122. Furthermore, the motor-side rotating shaft 122 is connected to the pump-side rotating shaft 120 and rotates integrally with the pump-side rotating shaft 120.

[0047] The electric motor 111 further comprises a motor housing 133 to which eddy current damper devices 1B and 1C are fixed, rotatably supporting the motor-side rotating shaft 122. The eddy current damper devices 1B and 1C are positioned on both sides of the motor rotor 131 in the axial direction of the motor-side rotating shaft 122. The motor rotor 131, motor stator 132, and eddy current damper devices 1B and 1C are housed within the motor housing 133.

[0048] When power is supplied to the electric motor 111 via a power cable (not shown), the electric motor 111 rotates the pump-side rotating shaft 120 and the impeller 125 together. As the impeller 125 rotates, the liquefied gas is drawn into the pump 110 through the suction port 127 and discharged through the discharge passage 116.

[0049] The yoke 20 of the eddy current damper device 1A is fixed to the pump casing 126, and the yokes 20 of the eddy current damper devices 1B and 1C are fixed to the motor housing 133. According to the embodiment shown in Figure 15, the rotating bodies, the pump-side rotating shaft 120 and the motor-side rotating shaft 122, are rotatably supported by the eddy current damper devices 1A, 1B, and 1C, and vibrations of the pump-side rotating shaft 120 and the motor-side rotating shaft 122 are damped by the eddy current damper devices 1A, 1B, and 1C.

[0050] Figure 16 is a cross-sectional view showing one embodiment of a rotating machine equipped with an eddy current damper device. The configuration of this embodiment, which is not specifically described, is the same as that of the embodiment described with reference to Figure 15, so redundant descriptions are omitted. In this embodiment, the eddy current damper device 1 rotatably supports the central portion of the pump-side rotating shaft 120. The yoke 20 of the eddy current damper device 1 is fixed to the pump stator 140, which forms a flow path for liquefied gas. In other embodiments, the yoke 20 of the eddy current damper device 1 may be fixed to the pump casing 126. The eddy current damper device 1 is one of the embodiments described with reference to Figures 1 to 7. The motor-side rotating shaft 122 of the electric motor 111 is rotatably supported by rolling bearings 141 and 142, and the end of the pump-side rotating shaft 120 is rotatably supported by a sliding bearing 143.

[0051] According to the embodiment shown in Figure 16, the pump-side rotating shaft 120, which is a rotating body, is rotatably supported by the eddy current damper device 1, and vibrations of the pump-side rotating shaft 120 are damped by the eddy current damper device 1.

[0052] The temperature at which rubber can maintain its viscoelasticity or oil can maintain its fluidity is higher than the temperature of the liquefied gas. For this reason, damper devices using rubber or oil cannot be used in pump devices that use liquefied gas. In this respect, the eddy current damper device 1, described with reference to Figures 1 to 13, does not use rubber or oil for vibration damping. Therefore, the eddy current damper device 1 can be used in cryogenic environments. For example, the usable temperature of the eddy current damper device 1 is below -100°C, specifically below -162°C (below the temperature of liquefied natural gas), and more specifically below -253°C (below the boiling point of hydrogen).

[0053] The pumping apparatus shown in Figures 15 and 16 is an example of a rotating machine. Other examples of rotating machines include blowers, turbo-rotating machines, and turbine generators. The configuration of a turbine generator differs from that of the pumping apparatus shown in Figures 15 and 16 in that a turbine is used instead of an impeller to pressurize the liquid. However, the basic configuration of a turbine generator is the same as that of a pumping apparatus, so it is omitted from the illustration.

[0054] The embodiments described above are intended to enable persons with ordinary skill in the art to implement the present invention. Various modifications of the above embodiments can be made naturally by those skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments as well. Therefore, the present invention is not limited to the embodiments described, but is to be interpreted in the broadest sense according to the technical idea defined by the claims. [Explanation of symbols]

[0055] 1,1A,1B,1C Eddy Current Damper Device 2. Solids of revolution 5 bearings 7. Cylindrical body 10 Conductor Plates 10a,10b side 10c Outer end face 14,15 Magnets 14a,15a Inner side 14b,15b Outer surface 20 York 20a Inner surface 24,25,26 wall 31, 32, 33, 34 Slits 35 Helical slits 41,42 Auxiliary magnets 41a,42a Inner surface 41b,42b Outer surface 51, 52 Electromagnet 51a,52a side 110 pump 111 Electric motor 116 Discharge passage 120 Pump-side rotating shaft 122 Motor-side rotating shaft 125 Impeller 126 Pump Casing 127 Inlet 131 Motor Rotor 132 Motor Stator 133 Motor Housing 140 Pump Stator

Claims

1. An eddy current damper device for suppressing vibrations of a rotating body, A bearing for rotatably supporting the aforementioned rotating body, A cylindrical body that holds the bearing, A conductive plate protruding radially outward from the outer surface of the cylindrical body, A magnet is positioned adjacent to the side surface of the conductor plate in the axial direction of the cylindrical body, The conductor plate and the magnet are surrounded by a yoke, The outer end face of the conductor plate is in contact with the yoke and is held by the yoke. The conductor plate has slits that impart elasticity to the conductor plate, The slit extends around the entire circumference of the conductive plate, forming an eddy current damper device.

2. The eddy current damper device according to claim 1, wherein the slit includes multiple arc-shaped slits extending around the entire circumference of the conductor plate.

3. The eddy current damper device according to claim 2, wherein the multiple arc slits include a plurality of semi-circular arc slits with different radii of curvature.

4. The eddy current damper device according to claim 1, wherein the slit includes a helical slit extending around the entire circumference of the conductor plate.

5. The axis of rotation and An impeller or turbine fixed to the aforementioned rotating shaft, An electric motor that rotates the aforementioned rotating shaft, A rotating machine comprising an eddy current damper device according to any one of claims 1 to 4, which rotatably supports the rotating shaft.

6. The rotating machine according to claim 5, wherein the rotating machine is a pumping device for transferring liquefied gas.

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