JP2013231471A - Fluid transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid transfer device capable of further increasing a thrust shaft support force.SOLUTION: A centrifugal pump 10 is provided with a housing 12, a rotation unit 14 rotated with a rotary shaft L as its center, an impeller 16, a motor unit 18 for applying torque to the rotation unit 14, radial shaft supporting units 20, 26, a thrust shaft supporting unit 22 which has a first permanent magnet 80 provided in the housing 12 and a second permanent magnet 84 provided in the rotation unit 14, and causes thrust shaft support force in a direction opposite to a direction of external force acting on the impeller 16 to act to the rotation unit 14, by first magnetic flux generated between the first permanent magnet 80 and the second permanent magnet 84, a thrust shaft supporting coil 26 for generating second magnetic flux superimposed on the first magnetic flux, and a control unit 30 for controlling a magnitude of DC current applied to the thrust shaft supporting coil 26.

Description

  The present invention relates to a fluid transfer device that transfers fluid such as liquid and gas.

  As a conventional fluid transfer device, a bearingless pump without a bearing is known. A general bearingless pump has a pump part and a motor part, and the rotating shaft of the pump part and the rotating shaft of the motor part are integrally formed continuously in the axial direction. The motor unit includes a stator provided on the housing and a rotor provided on the rotating shaft, and the rotor is supported by magnetic force in a non-contact state with respect to the stator. On the surfaces of the stator and the rotor, a chemical-resistant coating layer made of a fluororesin or the like is formed in order to prevent corrosion due to fluid. According to the bearingless pump, since the stator and the rotor do not mechanically contact with each other, it is possible to suppress wear of parts and generation of foreign matters. However, in order to obtain the magnetic force to support the rotor, it is necessary to keep the gap length between the stator and the rotor short, so it is difficult to increase the chemical resistance by increasing the coating layer. . Therefore, one of the inventors of the present case has proposed a bearingless motor and a pump that can obtain a sufficient shaft support force even when the gap length is long (see Patent Document 1).

  The bearingless motor and pump described in Patent Document 1 include two bearingless motor units that perform shaft support control in two axes orthogonal to the rotation axis, and shaft support control in one axis that is parallel to the rotation axis. One thrust magnetic bearing unit. The thrust magnetic bearing unit has a thrust shaft support winding wound around a rotating shaft, and a thrust permanent magnet for generating a bias magnetic flux is disposed on both axial sides of the thrust shaft support winding. . When a direct current is passed through the thrust shaft support winding, a thrust shaft support magnetic flux is generated, the thrust shaft support magnetic flux is superimposed on one bias magnetic flux, and the other bias magnetic flux is canceled by the thrust shaft support magnetic flux. As a result, a sparse part and a dense part are generated in the magnetic field, and a thrust shaft supporting force in a direction from the sparse part to the dense part acts on the rotor.

Japanese Patent No. 4616405

  According to the bearingless motor and the pump described in Patent Document 1, the radial shaft supporting force for supporting the rotor can be secured by the two bearingless motor units. However, it is still difficult to secure a sufficient thrust shaft support force, and there is room for improvement in the thrust shaft support force.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fluid transfer device that can further increase the thrust shaft support force.

  In order to solve the above-described problems, a fluid transfer device according to the present invention is provided at a housing, a rotating unit disposed inside the housing and rotated about a rotating shaft, and an axial end of the rotating unit. And an action part for acting a transfer force for transferring the fluid on the fluid, a stator provided in the housing, and provided in the rotary part apart from the stator in a direction orthogonal to the rotation axis. A motor unit that has a rotor and applies rotational force to the rotating unit; and a motor unit that is spaced apart from the motor unit in a direction parallel to the rotation axis, and the rotation in a direction orthogonal to the rotation axis. A radial shaft support portion that supports the portion in a non-contact manner, a first permanent magnet provided in the housing, and a second permanent magnet provided in the rotating portion, and the first permanent magnet and the second permanent magnet. Between the magnet and The first magnetic flux generates a thrust shaft support portion that causes a thrust shaft support force in a direction opposite to the direction of the external force acting on the action portion to act on the rotating portion, and a second magnetic flux that is superimposed on the first magnetic flux. A thrust shaft support coil and a control unit that controls the magnitude of a direct current applied to the thrust shaft support coil.

  In this configuration, a thrust shaft support force in a direction opposite to the direction of the external force acting on the action portion can be applied to the rotating portion by the first magnetic flux generated by the thrust shaft support portion. Further, a larger thrust shaft support force can be easily obtained by superimposing the second magnetic flux generated by the thrust shaft support coil on the first magnetic flux. And the magnitude | size of thrust shaft support force can be adjusted suitably by controlling the magnitude | size of the direct current provided to a thrust axis | shaft support coil by a control part, and adjusting the magnitude | size of a 2nd magnetic flux.

  The thrust shaft support portion is provided in the housing and divides the flow of the first magnetic flux into two, and a first fixed portion that is provided in the housing and guides one of the divided first magnetic fluxes. A magnetic part and a second fixed magnetic part that is provided in the housing and guides the other first magnetic flux that has been shunted; the first fixed magnetic part and the second fixed magnetic part are configured to rotate The magnetic flux density of the first magnetic flux is configured to be spaced apart in a direction parallel to the shaft, and the thrust shaft support coil includes the first fixed magnetic portion and the second fixed magnetic portion. Are arranged between the first fixed magnetic part and the second fixed magnetic part so that the second magnetic flux can be superimposed on the first magnetic flux flowing through any one of the first fixed magnetic part, One of the second fixed magnetic parts When the second magnetic flux in the first magnetic flux flowing is superimposed, or may be the first magnetic flux flowing through the other is offset by the second magnetic flux.

  In this configuration, the first fixed magnetic portion and the second fixed magnetic portion are configured to have a difference in the magnetic flux density of the first magnetic flux with an interval in the direction parallel to the rotation axis. Of the fixed magnetic part and the second fixed magnetic part, a thrust shaft supporting force in a direction from one sparse magnetic flux density to the other dense magnetic field can be applied to the rotating part. Further, when the second magnetic flux is superimposed on the first magnetic flux that flows through one of the first fixed magnetic portion and the second fixed magnetic portion, the first magnetic flux that flows through the other is offset by the second magnetic flux, so that the direct current By controlling the direction and magnitude of the thrust shaft, the direction and magnitude of the thrust shaft support force can be appropriately adjusted.

  The first permanent magnet and the second permanent magnet are arranged around the rotation shaft so as to generate the first magnetic flux radially, and the radial shaft support portion is configured to overlap the first magnetic flux. A radial shaft supporting winding for generating a magnetic flux; the third magnetic flux is superimposed on a predetermined first portion of the radial first magnetic flux; and on the opposite side of the first portion across the rotating shaft The second portion positioned may be offset by the third magnetic flux.

  When the third magnetic flux is superimposed on the predetermined first portion of the radial first magnetic flux and the second portion is canceled by the third magnetic flux, the second portion having a low magnetic flux density is changed to the first portion having a high magnetic flux density. Radial shaft support force is generated in the direction of heading. In the above configuration, since the permanent magnet is shared between the thrust shaft support portion and the radial shaft support portion, the permanent magnet can be omitted in either the thrust shaft support portion or the radial shaft support portion.

  A third permanent magnet provided in the housing and a fourth permanent magnet provided in the rotating portion, wherein the third permanent magnet and the fourth permanent magnet are parallel to the rotation axis in the motor. Radial radial direction opposite to the direction of the external force acting on the action part by the magnetic flux generated between the third permanent magnet and the fourth permanent magnet. The thrust shaft supporting force may be applied to the rotating portion.

  In this configuration, the thrust shaft supporting force in the direction opposite to the direction of the external force acting on the acting portion can be applied to the rotating portion at a position separated from the motor portion toward the acting portion side. You can gain power.

  A sensor target made of a magnetic material provided in the rotating part; a displacement sensor for detecting a displacement of the sensor target in a direction parallel to the rotation axis; and a direction of an external force provided in the housing and acting on the action part. Includes a fifth permanent magnet that applies a thrust shaft supporting force in the opposite direction to the sensor target, and a through-hole through which a fluid flows is formed in the central portion of the rotating portion so as to extend in the axial direction. The sensor target may be disposed around the through hole, and the displacement sensor may be disposed at a position off the extended line of the rotation shaft.

  In this configuration, since the thrust shaft support force is obtained by applying the magnetic force of the fifth permanent magnet to the sensor target, it is not necessary to provide a magnetic part separately from the sensor target, thereby reducing cost and weight. Can be planned. The sensor target is disposed around the through hole, and the displacement sensor is disposed at a position off the extended line of the rotation shaft, so that the sensor target and the displacement sensor impede the flow of fluid flowing through the through hole. Can be suppressed.

  According to the present invention, the thrust shaft support force can be further increased with the above-described configuration while the current applied to the thrust shaft support coil is kept small.

It is sectional drawing which shows the whole structure of the centrifugal pump (fluid transfer apparatus) which concerns on embodiment. It is a perspective view which shows the structure of the principal part of the centrifugal pump (fluid transfer apparatus) which concerns on embodiment. It is a figure which shows the generation | occurrence | production principle of radial shaft support force. It is a figure which shows distribution of the magnetic force line in a 1st radial shaft support part. It is a figure which shows distribution of the magnetic force line in a 1st thrust shaft support part, (A) is a figure which shows the state which made the 2nd magnetic flux superimpose on the 1st fixed magnetic part, and (B) is 2nd. It is a figure which shows the state which superimposed the 2nd magnetic flux on the 1st magnetic flux in the fixed magnetic part. It is a figure which shows distribution of the magnetic force line in a 2nd thrust shaft support part.

  Hereinafter, a preferred embodiment of a fluid transfer device according to the present invention will be described with reference to the drawings. In the following embodiments, the “fluid transfer device” according to the present invention is applied to a centrifugal pump for transferring a liquid.

  FIG. 1 is a cross-sectional view illustrating an overall configuration of a centrifugal pump 10 according to the embodiment, and FIG. 2 is a perspective view illustrating a configuration of a main part of the centrifugal pump 10. FIG. 3 is a diagram showing the principle of generation of the radial shaft support force Fβ.

  As shown in FIG. 1, the centrifugal pump 10 includes a housing 12, a rotating unit 14, an impeller 16, a motor unit 18, a first radial shaft support unit 20, a second radial shaft support unit 22, and a first A thrust shaft support portion 23, a second thrust shaft support portion 24, a thrust shaft support coil 26, and a third thrust shaft support portion 28 are provided. The centrifugal pump 10 also controls the power supply unit 29 and a power supply unit 29 that supplies current to each of the motor unit 18, the first radial shaft support unit 20, the second radial shaft support unit 22, and the thrust shaft support coil 26. And a control unit 30.

  As shown in FIG. 1, the housing 12 has a substantially bottomed cylindrical motor housing 32 and a substantially conical pump housing 34, and a base end portion of the pump housing 34 is formed in an opening of the motor housing 32. Is connected. A suction port 34 a is formed at the axial end of the pump housing 34, and a discharge port 34 b is formed at the side of the pump housing 34. The suction port 34 a and the discharge port 34 b are communicated with each other through the internal space of the pump housing 34.

  The rotating portion 14 is a portion that extends in the horizontal direction inside the housing 12 and is rotated about the rotation axis L, and has a substantially rod shape or a length that is substantially the same as the axial length of the motor housing 32. It has a pipe-shaped shaft portion 36. A through hole 15 for circulating a fluid inside the housing 12 is formed in the central portion of the rotating portion 14 and the impeller 16 (that is, the central portion of the shaft portion 36) extending in the axial direction.

  The impeller 16 is a portion that functions as an “action portion” that applies a transfer force for transferring the liquid to the liquid, and is disposed inside the pump housing 34 in a state of being attached to the axial end portion of the rotating portion 14. Yes. When the impeller 16 is rotated along with the rotation of the rotating portion 14, a centrifugal force acts on the liquid inside the pump housing 34, and the liquid is transferred from the center portion of the impeller 16 toward the outside in the radial direction. And discharged from the discharge port 34b. Thereby, the vicinity of the suction port 34a in the internal space of the pump housing 34 has a negative pressure, and a new liquid is taken into the pump housing 34 from the suction port 34a by the negative pressure. In FIG. 1, white arrows indicate the flow of liquid.

  When the impeller 16 is rotated, an external force directed toward the suction port 34a acts on the impeller 16 due to the negative pressure. At this time, the external force is canceled out by the thrust shaft support force Fγ in the reverse direction generated by the thrust shaft support portions 23, 24, 28, etc. (Fγ = F1p + F2p + F2a + F3p, FIG. 2). There is no contact. In this embodiment, for convenience of explanation, the direction of the thrust shaft support force Fγ is the thrust direction γ, the vertical direction orthogonal to the thrust direction γ is the vertical radial direction β, and the horizontal direction orthogonal to the thrust direction γ is The horizontal radial direction α is used. Further, the right direction in FIG. 1 is a positive thrust direction γ, the left direction is a negative thrust direction γ, the upward direction in FIG. 1 is a positive vertical radial direction β, and the downward direction is a negative vertical radial direction β. The forward direction in FIG. 5 is defined as a positive horizontal radial direction α, and the depth direction is defined as a negative horizontal radial direction α.

  As shown in FIG. 1, the motor unit 18 is a portion that applies a rotational force to the rotating unit 14, and is separated from the stator 40 in a direction orthogonal to the stator 40 provided on the housing 12 and the rotation axis L. And a rotor 42 provided in the rotating unit 14. The stator 40 includes a fixed magnetic portion 44 made of a magnetic material such as iron and an electric motor winding 46 wound around the fixed magnetic portion 44, and the electric motor winding 46 is electrically connected to the power supply portion 29. Connected. On the other hand, the rotor 42 has a plurality of permanent magnets 48 arranged around the rotation axis L. The motor unit 18 is disposed at the central portion in the axial direction of the rotating unit 14, and the first radial shaft support unit 20 and the second radial shaft support unit 22 are disposed on both sides in the axial direction across the motor unit 18. .

  As shown in FIG. 1, the first radial shaft support portion 20 is a portion that supports the rotation portion 14 in a non-contact manner in two axes orthogonal to the rotation axis L (that is, the vertical radial direction β and the horizontal radial direction α). The motor unit 18 is spaced apart in the negative thrust direction γ (that is, the impeller 16 side). The first radial shaft support portion 20 includes a stator 50 provided on the housing 12 and a rotor 52 provided on the rotation portion 14 so as to be separated from the stator 50 in a direction orthogonal to the rotation axis L. ing. The stator 50 includes two fixed magnetic portions 54 and 56 made of a magnetic material such as iron, a radial shaft support winding 58 wound around one fixed magnetic portion 54, and two fixed magnetic portions 54 and 56. Both have permanent magnets 60 connected with different magnetic poles. In the present embodiment, the south pole of the permanent magnet 60 is connected to one fixed magnetic portion 54, and the north pole is connected to the other fixed magnetic portion 56. The radial shaft support winding 58 is electrically connected to the power supply unit 29. On the other hand, the rotor 52 includes two rotating magnetic parts 62 and 64 made of a magnetic material such as iron and facing the two fixed magnetic parts 54 and 56 with a gap therebetween, and two rotating magnetic parts 62 and 64. Both have permanent magnets 66 connected with different magnetic poles. In the present embodiment, the N pole of the permanent magnet 66 is connected to one rotating magnetic unit 62, and the S pole is connected to the other rotating magnetic unit 64.

  As shown in FIG. 1, the two permanent magnets 60 and 66 are arranged around the rotation axis L so as to generate a radial bias magnetic flux Ψs1 between the stator 50 and the rotor 52, and the radial axis The support winding 58 has radial shaft support magnetic fluxes Ψs2β and Ψs2α (FIG. 3) superimposed on a predetermined first part of the radial bias magnetic flux Ψs1 (FIG. 3), and is opposite to the first part across the rotation axis L. The second portion located on the side is arranged so as to cancel out by the radial shaft supporting magnetic fluxes ψs2β and ψs2α (FIG. 3). As shown in FIG. 3, when a direct current is applied to the radial shaft support winding 58 to generate a two-pole radial shaft support magnetic flux ψs2β, the radial shaft support magnetic flux ψs2β is superimposed on the radial bias magnetic flux ψs1. In addition, the lower portion of the radial bias magnetic flux ψs1 is canceled by the radial axis support magnetic flux ψs2β. That is, in the vertical radial direction β, the upper part of the radial bias magnetic flux Ψs1 is a “first part” where the magnetic flux is dense, and the lower part is a “second part” where the magnetic flux is sparse. As a result, the radial shaft support force Fβ in the positive vertical radial direction β (upward) acts on the rotating portion 14. On the other hand, in the horizontal radial direction α, the radial shaft support force in the positive horizontal radial direction α acts on the rotating portion 14 by the two-pole radial shaft support magnetic flux Ψs2α generated by the other radial shaft support winding 58.

  As shown in FIG. 1, a substantially cylindrical sensor target 67 made of a magnetic material such as iron is centered on the rotation axis L at the axial end of the rotation unit 14 located in the vicinity of the first radial shaft support unit 20. It is provided as. On the other hand, a displacement sensor 68 that detects the displacement of the sensor target 67 in the vertical radial direction β is provided in the housing 12 so as to face the upper portion of the sensor target 67. The displacement sensor 68 is electrically connected to the control unit 30. Therefore, by detecting the displacement of the sensor target 67 by the displacement sensor 68, it is possible to detect the displacement of the rotating unit 14 in the vertical radial direction β. The control unit 30 controls the magnitude of the direct current applied to the radial shaft support winding 58 by controlling the operation of the power supply unit 29 so that the displacement of the rotating unit 14 becomes a predetermined value.

  As shown in FIG. 4, the fixed magnetic portion 56 of the stator 50 is arranged so as to be shifted in the positive thrust direction γ from the corresponding rotating magnetic portion 64 of the rotor 52. Therefore, the bias magnetic flux ψs1 flowing through the fixed magnetic portion 56 and the rotating magnetic portion 64 flows through the gap G between them at an inclination with respect to the direction orthogonal to the rotation axis L (FIG. 2). A passive first thrust shaft support force F1p (FIG. 2) in the thrust direction γ acts on the rotating portion 14. That is, in the present embodiment, the permanent magnet 60 (that is, the third permanent magnet) provided in the housing 12, the permanent magnet 66 (that is, the fourth permanent magnet) provided in the rotating portion 14, the fixed magnetic portion 56, A first thrust shaft support portion 23 is constituted by the rotating magnetic portion 64. The direction of the external force acting on the impeller 16 (FIG. 1) is reversed by the bias magnetic flux Ψs1 generated between the permanent magnet 60 and the permanent magnet 66 (that is, between the third permanent magnet and the fourth permanent magnet). The first thrust shaft support force F1p (FIG. 2) in the direction acts on the rotating portion 14.

  As shown in FIG. 1, the second radial shaft support portion 22 is a portion that supports the rotation portion 14 in a non-contact manner on two axes orthogonal to the rotation axis L (that is, the vertical radial direction β and the horizontal radial direction α). Yes, and is provided integrally with the second thrust shaft support portion 24 so as to be separated from the motor portion 18 in the positive thrust direction γ. The second radial shaft support portion 22 includes a stator 70 provided on the housing 12 and a rotor 72 provided on the rotation portion 14 so as to be separated from the stator 70 in a direction orthogonal to the rotation axis L. ing. The stator 70 includes two fixed magnetic parts 74 and 76 made of a magnetic material such as iron and spaced apart from each other in the thrust direction γ, and a radial shaft support winding wound around the one fixed magnetic part 74. 78 and a permanent magnet 80 connected to both of the two fixed magnetic portions 74 and 76 by different magnetic poles. In the present embodiment, the S pole of the permanent magnet 80 is connected to one fixed magnetic part 74, and the N pole is connected to the other fixed magnetic part 76. The radial shaft support winding 78 is electrically connected to the power supply unit 29. On the other hand, the rotor 72 includes a rotating magnetic part 82 made of a magnetic material such as iron and facing the fixed magnetic part 74 with a gap therebetween, and a permanent magnet 84 connected to the rotating magnetic part 82. . In the present embodiment, the N pole of the permanent magnet 84 is connected to the rotating magnetic part 82, and the S pole is opposed to the fixed magnetic part 76 with a gap.

  The permanent magnets 80 and 84 are arranged around the rotation axis L so as to generate a radial bias magnetic flux Ψs2 (FIG. 2) between the stator 70 and the rotor 72, and the radial shaft support winding 78 is , A radial shaft supporting magnetic flux (that is, the third magnetic flux; the same applies hereinafter) is superimposed on a predetermined first portion of the radial bias magnetic flux ψs2 (FIG. 2), and the opposite side of the first portion across the rotation axis L It arrange | positions so that the 2nd part located in may be canceled with a radial shaft support magnetic flux. The principle of generation of the radial shaft support force Fβ in the second radial shaft support portion 22 is the same as the principle of generation of the radial shaft support force Fβ in the first radial shaft support portion 20 (FIG. 3). In the vertical radial direction β, the upper part of the radial bias magnetic flux Ψs2 (FIG. 2) is a “first part” where the magnetic flux is dense, and the lower part is a “second part” where the magnetic flux is sparse. As a result, the radial shaft support force Fβ in the positive vertical radial direction β (upward) acts on the rotating portion 14. On the other hand, in the horizontal radial direction α, the radial shaft support force in the positive horizontal radial direction α acts on the rotating portion 14 by the two-pole radial shaft support magnetic flux generated by the other radial shaft support winding 58.

  As shown in FIG. 1, a substantially cylindrical sensor target 87 made of a magnetic material such as iron is provided at the axial end of the rotating unit 14 located in the vicinity of the second radial shaft support unit 22. It is arrange | positioned around the through-hole 15 as a center. On the other hand, a displacement sensor 88 that detects the displacement of the sensor target 87 in the vertical radial direction β in the vertical radial direction β is provided on the housing 12 so as to face the upper portion of the sensor target 87. A displacement sensor 88 is electrically connected to the control unit 30. Therefore, by detecting the displacement of the sensor target 87 by the displacement sensor 88, it is possible to detect the displacement of the rotating unit 14 in the vertical radial direction β. The control unit 30 controls the magnitude of the direct current applied to the radial shaft support winding 78 by controlling the operation of the power supply unit 29 so that the displacement of the rotating unit 14 becomes a predetermined value.

  As shown in FIG. 1, the second thrust shaft support portion 24 has a second thrust shaft support force F2p in a direction (positive thrust direction γ) opposite to the direction of the external force acting on the impeller 16 as the “action portion”. (FIG. 2) is a portion that acts on the rotating portion 14, and includes a permanent magnet 80 (that is, a first permanent magnet), a magnetic flux diverting portion 90, a fixed magnetic portion 76, a fixed magnetic portion 92, and a rotating portion provided in the housing 12. 14 has a permanent magnet 84 (that is, a second permanent magnet) and a rotating magnetic part 94. In the second thrust shaft support portion 24, for convenience of explanation, the permanent magnet 80 provided in the housing 12 is referred to as “first permanent magnet 80”, and the permanent magnet 84 provided in the rotating portion 14 is referred to as “second permanent magnet”. 84 ". One fixed magnetic portion 76 is referred to as a “first fixed magnetic portion 76”, and the other fixed magnetic portion 92 is referred to as a “second fixed magnetic portion 92”. The “bias magnetic flux ψs2” is referred to as “first magnetic flux ψs2”.

  As shown in FIG. 2, the first permanent magnet 80 and the second permanent magnet 84 generate the first magnetic flux Ψs2 for generating the second thrust shaft support force F2p. This is a portion that divides the flow of the first magnetic flux Ψs2 given from the north pole of the permanent magnet 80 into two. The first fixed magnetic part 76 is a part that guides one of the divided first magnetic fluxes Ψs2 to the rotating magnetic part 94, and the second fixed magnetic part 92 guides the other divided first magnetic flux Ψs2 to the rotating magnetic part 94. Part. The rotating magnetic part 94 is a part that joins the first magnetic flux Ψs2 given from each of the first fixed magnetic part 76 and the second fixed magnetic part 92 and guides it to the S pole of the second permanent magnet 84. Each of the magnetic flux shunt 90, the first fixed magnetic unit 76, the second fixed magnetic unit 92, and the rotating magnetic unit 94 is formed of a magnetic material such as iron.

  As shown in FIG. 1, the first fixed magnetic part 76 and the second fixed magnetic part 92 are arranged in a parallel direction with respect to the rotation axis L, and are spaced apart from the first fixed magnetic part 76 and the second fixed magnetic part 92. The magnetic portion 92 is connected to the magnetic portion 92 via a magnetic flux diverting portion 90 at an end portion on the side separated from the rotation axis L in a direction orthogonal to the rotation axis L. Therefore, the overall cross-sectional shapes of the first fixed magnetic portion 76, the second fixed magnetic portion 92, and the magnetic flux diverting portion 90 are substantially groove-shaped (substantially U-shaped) opened to the rotation axis L side. The N pole of the first permanent magnet 80 is connected to the first fixed magnetic part 76, and the S pole of the second permanent magnet 84 is connected to the rotating magnetic part 94. In the present embodiment, the rotating magnetic portion 94 is disposed at an intermediate position between the first fixed magnetic portion 76 and the second fixed magnetic portion 92 in the direction parallel to the rotation axis L. The length of the first magnetic path R1 from the fixed magnetic portion 76 to the rotating magnetic portion 94 is the second magnetic field from the first permanent magnet 80 to the rotating magnetic portion 94 via the magnetic flux shunting portion 90 and the second fixed magnetic portion 92. It is shorter than the length of the path R2. As a result, the magnetic resistance of the first magnetic path R1 is smaller than the magnetic resistance of the second magnetic path R2. Therefore, the magnetic flux density of the first magnetic flux Ψs2 in the first fixed magnetic part 76 is larger than the magnetic flux density of the first magnetic flux Ψs2 in the second fixed magnetic part 92, and the magnetic flux density is changed from a sparse part to a dense part. A passive second thrust shaft support force F2p (FIG. 2) in the direction toward the direction, that is, the positive thrust direction γ, acts on the rotating portion 14. The magnetic resistance may be adjusted as appropriate by changing the cross-sectional area and magnetic permeability of the magnetic paths R1 and R2.

  As shown in FIG. 2, the thrust shaft support coil 26 generates a second magnetic flux Ψtγ (that is, a thrust shaft support magnetic flux) to be superimposed on the first magnetic flux ψs2, and the first fixed magnetic portion 76 and the second fixed magnetic portion. The first fixed magnetic portion 76 and the second fixed magnetic portion 92 are wound around the rotation axis L so that the second magnetic flux ψtγ can be superimposed on the first magnetic flux ψs2 flowing through one of the portions 92. It is arranged between. The thrust shaft support coil 26 is electrically connected to the power supply unit 29. When a direct current is applied to the thrust shaft support coil 26, the second magnetic flux Ψtγ is superimposed on the first magnetic flux Ψs2 flowing through one of the first fixed magnetic section 76 and the second fixed magnetic section 92 according to the direction of the direct current. Is done.

  As shown in FIG. 5A, when the second magnetic flux Ψtγ is superimposed on the first magnetic flux Ψs2 flowing through the first fixed magnetic part 76, the first magnetic flux Ψs2 flowing through the second fixed magnetic part 92 becomes the second magnetic flux Ψtγ. Is offset by Then, the difference between the magnetic flux density of the magnetic flux in the first fixed magnetic portion 76 and the magnetic flux density of the magnetic flux in the second fixed magnetic portion 92 increases, and the second thrust shaft support force F2p (FIG. 2) in the positive thrust direction γ is obtained. On the other hand, an active thrust shaft supporting force F2a (FIG. 2) in the same direction is added. On the other hand, as shown in FIG. 5B, when the second magnetic flux Ψtγ is superimposed on the first magnetic flux Ψs2 flowing through the second fixed magnetic part 92, the first magnetic flux Ψs2 flowing through the first fixed magnetic part 76 is second. It is canceled out by the magnetic flux Ψtγ. Then, the difference between the magnetic flux density of the magnetic flux in the first fixed magnetic portion 76 and the magnetic flux density of the magnetic flux in the second fixed magnetic portion 92 is reduced, or the magnetic flux density of the magnetic flux in the second fixed magnetic portion 92 is the first fixed magnetic portion. It becomes larger than the magnetic flux density of the magnetic flux in the part 76. Thereby, the thrust shaft support force F2a (FIG. 2) added to the second thrust shaft support force F2p (FIG. 2) is reduced, or the thrust shaft added to the second thrust shaft support force F2p (FIG. 2). The supporting force F2a (FIG. 2) becomes a negative value. As shown in FIG. 2, in normal operation, the second magnetic flux Ψtγ is superimposed on the first magnetic flux Ψs2 flowing through the first fixed magnetic portion 76, and the same direction with respect to the second thrust shaft support force F2p in the positive thrust direction γ. The thrust shaft support force F2a is added to obtain a larger thrust shaft support force F2p + F2a.

  As shown in FIG. 1, the third thrust shaft support portion 28 has a third thrust shaft support force F3p in a direction (positive thrust direction γ) opposite to the direction of the external force acting on the impeller 16 as the “action portion”. (FIG. 2) is a portion that acts on the rotating portion 14, and includes a fixing portion 100 provided at the end of the housing 12 in the positive thrust direction γ. The fixed portion 100 is provided at a central portion of a surface of the fixed magnetic portion 102 facing the sensor target 87 and a substantially disc-shaped fixed magnetic portion 102 made of a magnetic material such as iron whose central axis coincides with the rotation axis L. Furthermore, a substantially disk-shaped permanent magnet 104 (that is, a fifth permanent magnet) and a substantially annular permanent magnet 106 (that is, a fifth permanent magnet) provided on the outer peripheral portion of the surface are included. In the present embodiment, the N pole of the permanent magnet 104 is connected to the fixed magnetic unit 102, and the S pole of the permanent magnet 106 is connected to the fixed magnetic unit 102. Then, as shown in FIG. 6, the magnetic flux Ψs3 generated by the permanent magnets 104 and 106 (that is, the fifth permanent magnet) acts on the sensor target 87, whereby the third thrust shaft support force F3p (in the positive thrust direction γ) ( FIG. 2) acts on the rotating part 14.

  As shown in FIG. 1, the end surface 87a of the sensor target 87 is disposed orthogonally to the rotation axis L, and the thrust direction is between two permanent magnets 104 and 106 forming one magnetic circuit. A displacement sensor 108 that detects the displacement of the sensor target 87 at γ is disposed opposite to the end surface 87 a of the sensor target 87 at a position off the extended line of the rotation axis L. The displacement sensor 108 is electrically connected to the control unit 30. Therefore, by detecting the displacement of the sensor target 87 by the displacement sensor 108, it is possible to detect the displacement of the rotating unit 14 in the thrust direction γ. The control unit 30 controls the direction and magnitude of the direct current applied to the thrust shaft support coil 26 by controlling the operation of the power supply unit 29 so that the displacement of the rotating unit 14 becomes a predetermined value.

  The respective cross-sectional areas of the magnetic path of the bias magnetic flux ψs1 (FIG. 2) in the first radial shaft support portion 20 and the magnetic path of the bias magnetic flux ψs2 (FIG. 2) in the second radial shaft support portion 22 are always the same. Designed to be small to cause magnetic saturation. Therefore, even when the position of the rotating portion 14 fluctuates in the thrust direction γ, both the bias magnetic flux ψs1 (FIG. 2) of the first radial shaft support portion 20 and the bias magnetic flux ψs2 (FIG. 2) of the second radial shaft support portion 22. Can suppress the fluctuation of the magnetic flux density, and can stabilize the radial shaft support force Fβ. As shown in FIG. 1, various components provided in the rotating unit 14 and various components provided in the housing 12 are covered with a chemical-resistant coating layer 110 made of a fluororesin or the like.

  According to the present embodiment, the following effects can be achieved by the above configuration. That is, as shown in FIG. 2, by superposing the second magnetic flux Ψtγ generated by the thrust shaft support coil 26 on the first magnetic flux Ψs2, the active thrust shaft support force is added to the passive second thrust shaft support force F2p. It is possible to add F2a, whereby a thrust shaft support force F2p + F2a larger than the second thrust shaft support force F2p can be easily obtained.

  By controlling the magnitude of the direct current applied to the thrust shaft support coil 26 by the control unit 30 (FIG. 1) and adjusting the magnitude of the second magnetic flux Ψtγ (FIG. 2), the thrust shaft support force F2p + F2a (FIG. The size of 2) can be adjusted as appropriate.

  As shown in FIG. 2, a passive first thrust shaft support force F1p in the positive thrust direction γ can be obtained at the first thrust shaft support portion 23, and the second thrust shaft support portion 24 and the thrust shaft support coil 26 can be obtained. Can obtain a passive second thrust shaft support force F2p and an active thrust shaft support force F2a in the positive thrust direction γ, and a passive member in the positive thrust direction γ can be obtained in the third thrust shaft support portion 28. Since the third thrust shaft support force F3p can be obtained, the thrust shaft support force Fγ (Fγ = F1p + F2p + F2a + F3p) having a sufficient size as a whole (in this embodiment, 718 N or more) can be easily obtained.

  As shown in FIG. 1, the permanent magnets 80 and 84 are shared between the second thrust shaft support portion 24 and the second radial shaft support portion 22, and the displacement sensor 88 in the vertical radial direction β and the thrust direction γ. Since the sensor target 87 is shared with the displacement sensor 108, the number of parts can be reduced and the cost can be reduced.

  As shown in FIG. 1, the sensor target 87 is disposed around the through-hole 15, and the displacement sensor 108 is disposed at a position off the extended line of the rotation axis L. The sensor 108 does not obstruct the flow of fluid flowing through the through hole 15. Thereby, the circulation of the fluid in the inside of the housing 12 can be promoted, and the pressure difference between the axial directions of the rotating part 14 can be reduced.

  As shown in FIG. 1, since the first radial shaft support portion 20 and the second radial shaft support portion 22 are spaced apart on both sides of the motor portion 18 in the thrust direction γ, the robustness of the radial position control is improved. Can be improved.

  In the above-described embodiment, the present invention is applied to a centrifugal pump that transfers a liquid. However, in another embodiment, the present invention may be applied to a blower that transfers gas.

  In the above-described embodiment, an external force in the negative thrust direction γ acts on the impeller 16 as the “acting portion”. However, in another embodiment, an external force in the positive thrust direction γ acts on the impeller and the like. In this case, the external force may be canceled by the thrust shaft support force Fγ in the negative thrust direction γ (Fγ = F1p + F2p + F2a + F3p) generated by the thrust shaft support portions 23, 24, 28, etc.

L ... Rotating shaft 10 ... Centrifugal pump (fluid transfer device)
DESCRIPTION OF SYMBOLS 12 ... Housing 14 ... Rotating part 16 ... Impeller 18 ... Motor part 20 ... 1st radial shaft support part 22 ... 2nd radial shaft support part 23 ... 1st thrust shaft support part 24 ... 2nd thrust shaft support part 26 ... Thrust shaft Support coil 28 ... Third thrust shaft support 29 ... Power supply 30 ... Control unit 80 ... First permanent magnet 84 ... Second permanent magnet

Claims (5)

A housing;
A rotating part disposed inside the housing and rotated about a rotation axis;
An action part that is provided at an axial end of the rotating part and causes a transfer force to transfer the fluid to act on the fluid;
A motor that includes a stator provided in the housing and a rotor provided in the rotating portion that is spaced apart from the stator in a direction orthogonal to the rotation axis, and that imparts rotational force to the rotating portion. And
A radial shaft support portion disposed away from the motor unit in a direction parallel to the rotation axis, and supporting the rotation unit in a non-contact manner in a direction orthogonal to the rotation axis;
A first permanent magnet provided in the housing and a second permanent magnet provided in the rotating portion, and the action by the first magnetic flux generated between the first permanent magnet and the second permanent magnet. A thrust shaft support portion that causes the rotation portion to act on a thrust shaft support force in a direction opposite to the direction of the external force acting on the portion;
A thrust shaft support coil for generating a second magnetic flux to be superimposed on the first magnetic flux;
A fluid transfer device comprising: a control unit that controls the magnitude of a direct current applied to the thrust shaft support coil. The thrust shaft support is
A magnetic flux diverting portion provided in the housing and diverting the flow of the first magnetic flux into two;
A first fixed magnetic part that is provided in the housing and guides one of the divided first magnetic fluxes;
A second fixed magnetic part that is provided in the housing and guides the other first magnetic flux that has been shunted;
The first fixed magnetic part and the second fixed magnetic part are configured so as to have a difference in magnetic flux density of the first magnetic flux with an interval in a direction parallel to the rotation axis,
The thrust shaft support coil includes the first fixed magnetic portion and the first fixed magnetic portion so that the second magnetic flux can be superimposed on the first magnetic flux flowing through one of the first fixed magnetic portion and the second fixed magnetic portion. It is arranged between two fixed magnetic parts,
When the second magnetic flux is superimposed on the first magnetic flux flowing through one of the first fixed magnetic portion and the second fixed magnetic portion, the first magnetic flux flowing through the other is canceled by the second magnetic flux. The fluid transfer device according to claim 1. The first permanent magnet and the second permanent magnet are arranged around the rotating shaft so as to generate the first magnetic flux radially;
The radial shaft support portion has a radial shaft support winding that generates a third magnetic flux to be superimposed on the first magnetic flux,
The third magnetic flux is superimposed on a predetermined first portion of the radial first magnetic flux, and the second portion located on the opposite side of the first portion across the rotating shaft is offset by the third magnetic flux; The fluid transfer device according to claim 2. A third permanent magnet provided in the housing and a fourth permanent magnet provided in the rotating portion;
The third permanent magnet and the fourth permanent magnet are disposed away from the motor portion toward the action portion in a direction parallel to the rotation axis,
The thrust shaft supporting force in the direction opposite to the direction of the external force acting on the acting portion is caused to act on the rotating portion by a magnetic flux generated between the third permanent magnet and the fourth permanent magnet. 4. The fluid transfer device according to any one of 3. A sensor target made of a magnetic material provided in the rotating part;
A displacement sensor for detecting a displacement of the sensor target in a direction parallel to the rotation axis;
A fifth permanent magnet provided on the housing and acting on the sensor target with a thrust shaft support force in a direction opposite to the direction of the external force acting on the acting portion;
A through hole for circulating a fluid inside the housing is formed extending in the axial direction at the center of the rotating part,
The sensor target is disposed around the through hole,
5. The fluid transfer device according to claim 1, wherein the displacement sensor is disposed at a position deviated from an extension line of the rotation shaft.

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