JP2010261394A - Centrifugal pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal pump device having high support stiffness of an impeller. <P>SOLUTION: In a centrifugal blood pump device, permanent magnets 15a, 15b are provided to one surface of an impeller 10, permanent magnets 16a, 16b are provided to an inner wall of a blood chamber 7, permanent magnets 50 are provided to another surface of the impeller 10, permanent magnets 51 and a rotor 52 which rotationally drive the impeller 10 through the partition wall 6 are provided, and dynamic pressure grooves 21, 22 are formed on inner walls of the partition wall 6 opposing to the impeller 10 and the inner wall of the blood chamber 7. Amount ΔF1 of variation in attraction force F1 between the permanent magnets 15a, 15b and the permanent magnets 16a, 16b and amount ΔF2 of variation in the attraction force F2 between the permanent magnets 50, 51, the variations being those which occur when the impeller 10 is eccentrically located, are made to be substantially agree with each other. Accordingly, a floating position of the impeller 10 can be always maintained at substantially a center within a housing 2, mechanical contact of the impeller 10 and the housing 2 can be reduced, and occurrence of erythrocytolysis and thrombus can be prevented. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a centrifugal pump device, and more particularly to a centrifugal pump device provided with an impeller that sends liquid by a centrifugal force during rotation.

  In recent years, an example of using a centrifugal blood pump device that transmits a driving torque of an external motor to an impeller in a blood chamber using a magnetic coupling is increasing as a blood circulation device of an oxygenator. According to this centrifugal blood pump device, physical communication between the outside and the blood chamber can be eliminated, and invasion of blood such as bacteria can be prevented.

  The centrifugal blood pump of Patent Document 1 includes a housing including first to third chambers partitioned by first and second partition walls, and an impeller provided rotatably in the second chamber (blood chamber). A magnetic body provided on one surface of the impeller, an electromagnet provided in the first chamber facing the one surface of the impeller, a permanent magnet provided on the other surface of the impeller, and a third chamber A rotor and a motor provided, and a permanent magnet provided on the rotor facing the other surface of the impeller. A dynamic pressure groove is formed on the surface of the second partition wall facing the other surface of the impeller. Due to the attractive force acting on one side of the impeller from the electromagnet, the attractive force acting on the other surface of the impeller from the permanent magnet of the rotor, and the hydrodynamic bearing effect of the dynamic pressure groove, the impeller is separated from the inner wall of the second chamber, Rotates without contact.

  Further, the centrifugal blood pump of Patent Document 2 is rotatably provided in a housing including first to third chambers partitioned by first and second partition walls, and a second chamber (blood chamber). An impeller, a magnetic body provided on one surface of the impeller, a first permanent magnet provided in the first chamber facing the one surface of the impeller, and a second provided on the other surface of the impeller A permanent magnet, a rotor and a motor provided in a third chamber, and a third permanent magnet provided on the rotor so as to face the other surface of the impeller. A first dynamic pressure shaft is formed on the surface of the first partition wall facing the one surface of the impeller, and a second dynamic pressure groove is formed on the surface of the second partition wall facing the other surface of the impeller. Yes. The attractive force acting on one surface of the impeller from the first permanent magnet, the attractive force acting on the other surface of the impeller from the third permanent magnet of the rotor, and the hydrodynamic bearing effect of the first and second dynamic pressure grooves Thus, the impeller is separated from the inner wall of the second chamber and rotates in a non-contact state.

  8 and 9 of Patent Document 3 includes a housing, an impeller provided rotatably in the housing, a first permanent magnet provided on one surface of the impeller, and an exterior of the housing. A rotor provided on the rotor, a second permanent magnet provided on the rotor facing the one surface of the impeller, a third permanent magnet provided on the other surface of the impeller, and a surface facing the other surface of the impeller And a magnetic body provided in the housing. A first dynamic pressure groove is formed on one surface of the impeller, and a second dynamic pressure groove is formed on the other surface of the impeller. Due to the attractive force acting on one side of the impeller from the second permanent magnet of the rotor, the attractive force acting on the other surface of the impeller from the magnetic body of the housing, and the hydrodynamic bearing effect of the first and second dynamic pressure grooves The impeller is separated from the inner wall of the housing and rotates in a non-contact state.

  Furthermore, the clean pump of Patent Document 4 includes a casing, an impeller provided rotatably in the casing, a first permanent magnet provided on one surface of the impeller, a rotor provided outside the casing, A second permanent magnet provided on the rotor facing one surface of the impeller, a magnetic body provided on the other surface of the impeller, and an electromagnet provided outside the housing facing the other surface of the impeller. ing. A dynamic pressure groove is formed on one surface of the impeller.

  When the rotational speed of the impeller is lower than the predetermined rotational speed, the electromagnet is operated, and when the rotational speed of the impeller exceeds the predetermined rotational speed, energization to the electromagnet is stopped. Due to the attractive force acting on one surface of the impeller from the second permanent magnet of the rotor and the hydrodynamic bearing effect of the hydrodynamic groove, the impeller is separated from the inner wall of the housing and rotates in a non-contact state.

Japanese Patent Laid-Open No. 2005209250 JP 2006-167173 A JP-A-4-91396 Japanese Utility Model Publication No. 6-53790

  The pumps of the above-mentioned patent documents 1 to 4 support the impeller in the axial direction (rotational axis direction of the impeller) by a dynamic pressure groove formed in the facing portion of the impeller and the housing, and the permanent magnet provided on the impeller and the outside of the housing This is common in that the radial direction of the impeller (radial direction of the impeller) is supported by the attraction force with the permanent magnet provided in.

  In such a centrifugal pump device, if the support rigidity of the impeller (the force required to move the impeller by a unit length) is small, the impeller is caused to vibrate due to the user's movement (acceleration vibration) and the inner wall of the blood chamber Will come into contact. Therefore, it is necessary to have a sufficiently large support rigidity in each of the axial direction and the radial direction.

  In order to increase the support rigidity of the impeller, the magnetic coupling force between the impeller permanent magnet and the housing-side permanent magnet may be increased. However, it is not easy to increase the magnetic coupling force. That is, in the hydrodynamic bearing type centrifugal pump device, first, the minimum value of the flow rate, the head (pressure), and the distance between the blood chamber and the impeller is given as specifications. Then, the rotation speed and the size of the dynamic pressure groove are determined by the diameter of the impeller.

  If the dimensions of the dynamic pressure groove, the diameter of the impeller, the number of rotations, and the distance between the blood chamber and the impeller are determined, the load capacity is determined, so that the magnetic coupling force for balancing it is determined. When the magnetic coupling force is determined, the support rigidity of the impeller is also determined. Therefore, in order to increase the support rigidity of the impeller, it is necessary to increase the load capacity, but the load capacity depends on the viscosity of the blood, the speed of the impeller, the size of the dynamic pressure groove, the distance between the blood chamber and the impeller, There is a limit to increasing the load capacity.

  In addition, the gap between the impeller end surface on which the dynamic pressure acts and the housing inner surface is formed on the impeller rotational torque generating part side and the impeller auxiliary suction part side, and both the gaps are substantially the same. The distance between them becomes the largest, and even if a disturbance force acts on the impeller, the end surface of the impeller hardly comes into contact with the inner surface of the housing. However, in a pump configuration in which a single volute or a volute is eliminated and the blood outflow port is placed in contact with the cylindrical housing, an imbalance in the pressure balance in the pump chamber occurs during the desired pump operation, and the impeller is in the blood outflow port. Since it moves in the radial direction so as to be sucked to the side, the suction force in the axial direction of both end faces of the impeller is reduced.

  Therefore, when the amount of change in the attractive force in the axial direction with respect to the radial displacement of the impeller rotational torque generating portion is different from the amount of change in the axial direction attractive force with respect to the radial displacement of the magnetic coupling portion formed in the impeller auxiliary suction portion, During the desired pump operation, the balance position of the suction force in the axial direction is moved from the substantially central position in the housing. As a result, one of the gaps between the impeller end surface and the housing inner surface is narrowed, the other is widened, and even if a small disturbance force acts on the impeller, the impeller end surface and the housing inner surface Becomes easy to contact.

  Therefore, the main object of the present invention is to provide a centrifugal pump device that is resistant to disturbance acting on the impeller without changing the floating gap between the impeller and the housing even when the impeller moves in the radial direction within the housing. Is to provide.

  A centrifugal pump device according to the present invention is provided with a housing including first and second chambers partitioned by a partition, and is rotatably provided along the partition in the first chamber. In a centrifugal pump device provided with a feeding impeller and a driving means provided in a second chamber and rotationally driving the impeller via a partition wall, a first magnetic body provided on one surface of the impeller, and the impeller The second magnetic body is provided on the inner wall of the first chamber facing the one surface, and attracts the first magnetic body, and the third magnetic body is provided on the other surface of the impeller. . During the rotation of the impeller, the first attraction force between the first and second magnetic bodies and the second attraction force between the third magnetic body and the driving means are within the movable range of the impeller in the first chamber. Balance in the approximate center. The change amount of the first suction force with respect to the eccentric amount of the impeller in the radial direction is substantially equal to the change amount of the second suction force with respect to the eccentric amount of the impeller in the radial direction. A first dynamic pressure groove is formed on one surface of the impeller or the inner wall of the first chamber facing it, and a second dynamic pressure groove is formed on the other surface of the impeller or a partition wall facing it.

  Preferably, the driving means includes a rotor that is rotatably provided along the partition wall in the second chamber, a fourth magnetic body that is provided in the rotor and that attracts the third magnetic body, and a motor that rotates the rotor. Including.

  Further preferably, the absolute value of the radial positive support rigidity value of the magnetic coupling portion constituted by the first and second magnetic bodies is the magnetic coupling portion constituted by the third and fourth magnetic bodies. It is larger than the absolute value of the positive support stiffness value in the radial direction.

  Preferably, the third magnetic body includes a plurality of magnets arranged along the same circle so that adjacent magnetic poles are different from each other, and the driving means is provided to face the plurality of magnets, and the rotating magnetic field Including a plurality of coils for generating.

  Preferably, the third magnetic body includes a plurality of magnets arranged along the same circle so that adjacent magnetic poles are different from each other. The driving means is provided corresponding to the plurality of fourth magnetic bodies provided to face the plurality of magnets, and each of the plurality of fourth magnetic bodies is wound around the corresponding fourth magnetic body. And a plurality of coils for generating a rotating magnetic field.

  Preferably, the second attractive force is adjusted by changing the phase of the current flowing through the plurality of coils.

  More preferably, the magnetic sensor further includes a magnetic sensor provided in the second chamber so as to face the plurality of magnets, and the phase of the current flowing through the plurality of coils is changed based on the output signal of the magnetic sensor.

  Also preferably, the liquid is blood and the centrifugal pump device is used to circulate blood.

  In the centrifugal pump device according to the present invention, the first and second suction forces acting on the impeller are balanced at the approximate center of the movable range of the impeller, and the first and second suction forces with respect to the radial eccentricity of the impeller. The first and second dynamic pressure grooves were formed with substantially the same amount of change. Therefore, even when the impeller moves in the radial direction within the housing, it is possible to improve resistance to disturbances acting on the impeller without changing the floating gap between the impeller and the housing.

It is a front view which shows the external appearance of the pump part of the centrifugal blood pump apparatus by Embodiment 1 of this invention. It is a side view of the pump part shown in FIG. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a figure which shows the permanent magnet shown in FIG. It is sectional drawing which shows the state which removed the impeller from the IV-IV sectional view taken on the line of FIG. It is sectional drawing which shows the state which removed the impeller from the VII-VII sectional view taken on the line of FIG. It is the VIII-VIII sectional view taken on the line of FIG. It is a time chart which shows operation | movement of the magnetic sensor shown in FIG. It is a time chart which illustrates the voltage applied to a plurality of coils shown in FIG. It is a figure which shows the relationship between the floating position of an impeller and the acting force to an impeller. It is another figure which shows the relationship between the floating position of an impeller and the acting force to an impeller. It is a figure which shows the relationship between the eccentric amount of the radial direction of an impeller, and the acting force to an impeller. It is a block diagram which shows the structure of the controller which controls the pump part shown in FIGS. It is sectional drawing which shows the example of a change of this Embodiment 1. It is sectional drawing which shows the other example of a change of this Embodiment 1. FIG. 10 is a cross-sectional view showing still another modification example of the first embodiment. FIG. 10 is a cross-sectional view showing still another modification example of the first embodiment. FIG. 10 is a cross-sectional view showing still another modification example of the first embodiment. FIG. 10 is a cross-sectional view showing still another modification example of the first embodiment. FIG. 10 is a cross-sectional view showing still another modification example of the first embodiment. FIG. 10 is a cross-sectional view showing still another modification example of the first embodiment. FIG. 10 is a cross-sectional view showing still another modification example of the first embodiment. FIG. 10 is a cross-sectional view showing still another modification example of the first embodiment. FIG. 10 is a diagram showing still another modification example of the first embodiment. It is sectional drawing which shows the structure of the pump part of the centrifugal blood pump apparatus by Embodiment 2 of this invention. It is a figure for demonstrating the relationship between the diameter of the permanent magnets 50 and 51 shown in FIG. 26, and the eccentricity of the impeller. It is a figure which shows the relationship between the attractive force F2 of the permanent magnets 50 and 51 shown in FIG. 27, and the eccentric amount of an impeller. It is a figure which shows the example of a change of Embodiment 2. FIG. FIG. 30 is a diagram showing the relationship between the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b shown in FIG. 29 and the amount of eccentricity of the impeller.

[Embodiment 1]
As shown in FIGS. 1 and 2, the pump unit 1 of the centrifugal blood pump apparatus according to the first embodiment includes a housing 2 formed of a nonmagnetic material. The housing 2 includes a columnar main body 3, a cylindrical blood inflow port 4 erected at the center of one end surface of the main body 3, and a cylindrical blood outflow provided on the outer peripheral surface of the main body 3. Port 5 is included. The blood outflow port 5 extends in the tangential direction of the outer peripheral surface of the main body 3.

  In the housing 2, as shown in FIG. 3, a blood chamber 7 and a motor chamber 8 partitioned by a partition wall 6 are provided. In the blood chamber 7, as shown in FIGS. 3 and 4, a disc-like impeller 10 having a through hole 10a in the center is rotatably provided. The impeller 10 includes two shrouds 11 and 12 each having a donut plate shape and a plurality of (for example, six) vanes 13 formed between the two shrouds 11 and 12. The shroud 11 is disposed on the blood inlet port 4 side, and the shroud 12 is disposed on the partition wall 6 side. The shrouds 11 and 12 and the vane 13 are made of a nonmagnetic material.

  A plurality (six in this case) of blood passages 14 partitioned by a plurality of vanes 13 are formed between the two shrouds 11 and 12. As shown in FIG. 4, the blood passage 14 communicates with the central through hole 10 a of the impeller 10, and starts from the through hole 10 a of the impeller 10 and extends so that the width gradually increases to the outer peripheral edge. In other words, the vane 13 is formed between two adjacent blood passages 14. In the first embodiment, the plurality of vanes 13 are provided at equiangular intervals and formed in the same shape. Therefore, the plurality of blood passages 14 are provided at equiangular intervals and are formed in the same shape.

  When the impeller 10 is driven to rotate, the blood flowing in from the blood inflow port 4 is sent from the through hole 10a to the outer periphery of the impeller 10 through the blood passage 14 by centrifugal force and flows out from the blood outflow port 5.

  Further, permanent magnets 15 a and 15 b are embedded in the shroud 11, and permanent magnets 16 a and 16 b for attracting the permanent magnets 15 a and 15 b are respectively embedded in the inner wall of the blood chamber 7 facing the shroud 11. The permanent magnets 15a, 15b, 16a, 16b are provided for attracting (in other words, energizing) the impeller 10 to the side opposite to the motor chamber 8, in other words, to the blood inflow port 4 side.

  FIGS. 5A and 5B are diagrams showing the configuration of the permanent magnets 15a, 15b, 16a, and 16b, and FIG. 5A is a cross-sectional view taken along the line VA-VA in FIG. 5B. As shown in FIGS. 5A and 5B, each of the permanent magnets 15a and 15b is formed in an annular shape, and the outer diameter of the permanent magnet 15a is smaller than the inner diameter of the permanent magnet 15b. The permanent magnets 15 a and 15 b are provided coaxially, and the center points of the permanent magnets 15 a and 15 b are both arranged on the rotation center line of the impeller 10. In the figure, the end faces in the same direction of the permanent magnets 15a and 15b have the same polarity, but they may have different polarities.

  On the other hand, each of the permanent magnets 16 a and 16 b is formed in an arc shape, and two are arranged in the rotation direction of the impeller 10. The outer diameter and inner diameter of the two permanent magnets 16a arranged in an annular shape are the same as the outer diameter and inner diameter of the permanent magnet 15a. The outer diameter and inner diameter of the two permanent magnets 16b arranged in an annular shape are the same as the outer diameter and inner diameter of the permanent magnet 15b. In the figure, the end faces of the permanent magnets 16a and 16b in the same direction have the same polarity, but may have a configuration having different polarities. The permanent magnets 15a and 16a and the permanent magnets 15b and 16b are opposed to each other in a pole arrangement for attracting each other.

  Further, as shown in FIG. 3, the distance between the permanent magnets 15a and 15b (that is, the distance between the permanent magnets 16a and 16b) D1 is the radial movable distance of the impeller 10 (that is, the inner diameter of the blood chamber 7 and the outer diameter of the impeller 10). The distance D2 is set to be a half of the distance (D1> D2). This is because when D1 <D2, when the impeller 10 moves to the maximum in the radial direction, the permanent magnets 15a and 16b and the permanent magnets 15b and 16a interfere with each other to restore the impeller 10 to the pump center position. Because it becomes unstable.

  Thus, since the two pairs of permanent magnets 15a and 16a and the permanent magnets 15b and 16b are provided in the radial direction of the impeller 10, the impeller 10 is compared with the case where only one pair of permanent magnets is provided in the radial direction of the impeller 10. The support rigidity in the radial direction can be increased.

  Instead of providing permanent magnets 15a and 15b and permanent magnets 16a and 16b on the inner walls of the shroud 11 and blood chamber 7, respectively, a permanent magnet is provided on one of the inner walls of the shroud 11 and blood chamber 7, and a magnetic material is provided on the other. May be. Further, as the magnetic material, either a soft magnetic material or a hard magnetic material may be used.

  FIG. 3 shows the case where the opposing surfaces of the permanent magnets 15a and 16a have the same size and the opposing surfaces of the permanent magnets 15b and 16b have the same size. In order to prevent the rigidity of the impeller 10 from being lowered due to the attractive force of the permanent magnets 16a and 16b, the size of the opposed surfaces of the permanent magnets 15a and 16a is made different, and the size of the opposed surfaces of the permanent magnets 15b and 16b is made different. Is preferred. By making the sizes of the opposing surfaces of the permanent magnets 15a, 15b and the permanent magnets 16a, 16b different, the amount of change in the attractive force that changes depending on the distance between them, that is, the negative rigidity can be kept small, and the impeller 10 is supported. A decrease in rigidity can be prevented.

  5 (a) and 5 (b), each of the permanent magnets 15a and 15b is formed in an annular shape, and each of the permanent magnets 16a and 16b is formed in an arc shape so that the impeller 10 rotates at equal angular intervals. Although two are arranged, conversely, each of the permanent magnets 16a and 16b is formed in an annular shape, and each of the permanent magnets 15a and 15b is formed in an arc shape, and two are arranged at equal angular intervals in the rotation direction of the impeller 10. May be. Further, each of the permanent magnets 15a and 15b or each of the permanent magnets 16a and 16b may be formed in a shorter arc shape and arranged in plural in the rotation direction of the impeller 10 at equal angular intervals.

  As shown in FIGS. 3 and 4, a plurality (for example, eight) of permanent magnets 17 are embedded in the shroud 12. The plurality of permanent magnets 17 are arranged along the same circle at equal angular intervals so that adjacent magnetic poles are different from each other. In other words, the permanent magnets 17 with the N pole facing the motor chamber 8 side and the permanent magnets 17 with the S pole facing the motor chamber 8 side are alternately arranged along the same circle at equal angular intervals. .

  Further, as shown in FIGS. 3 and 8, a plurality of (for example, nine) magnetic bodies 18 are provided in the motor chamber 8. The plurality of magnetic bodies 18 are arranged along the same circle at equal angular intervals so as to face the plurality of permanent magnets 17 of the impeller 10. The base ends of the plurality of magnetic bodies 18 are joined to one disk-shaped yoke 19. A coil 20 is wound around each magnetic body 18.

  Also, three magnetic sensors SE are provided between three of the nine magnetic bodies 18 adjacent to each other. The three magnetic sensors SE are arranged to face the passage paths of the plurality of permanent magnets 17 of the impeller 10. When the impeller 10 rotates and the S poles and N poles of the plurality of permanent magnets 17 alternately pass in the vicinity of the magnetic sensor SE, the level of the output signal of the magnetic sensor SE changes like a sine wave as shown in FIG. To do. Therefore, by detecting the time change of the output signal of the magnetic sensor SE, the positional relationship between the plurality of permanent magnets 17 and the plurality of magnetic bodies 18 can be detected, and the timing of flowing current through the plurality of coils 20; The rotation speed of the impeller 10 can be obtained.

  Further, when the gap between the impeller 10 and the partition wall 6 is wide, the magnetic field in the vicinity of the magnetic sensor SE becomes weak and the amplitude A1 of the output signal of the magnetic sensor SE becomes small. When the gap between the impeller 10 and the partition wall 6 is narrow, the magnetic field in the vicinity of the magnetic sensor SE becomes strong and the amplitude A2 of the output signal of the magnetic sensor SE increases. Therefore, the position of the impeller 10 within the movable range of the impeller 10 can be detected by detecting the amplitude of the output signal of the magnetic sensor SE.

  For example, a voltage is applied to the nine coils 20 by a 120-degree conduction method. That is, nine coils 20 are grouped by three. Voltages VU, VV, and VW as shown in FIG. 10 are applied to the first to third coils 20 of each group. A positive voltage is applied to the first coil 20 during a period of 0 to 120 degrees, 0 V is applied during a period of 120 to 180 degrees, a negative voltage is applied during a period of 180 to 300 degrees, and 300 to 360 degrees. 0V is applied during this period. Therefore, the front end surface (end surface on the impeller 10 side) of the magnetic body 18 around which the first coil 20 is wound becomes the N pole in the period of 0 to 120 degrees and becomes the S pole in the period of 180 to 300 degrees. . The phase of the voltage VV is 120 degrees behind the voltage VU, and the phase of the voltage VW is 120 degrees behind the voltage VV. Therefore, by applying the voltages VU, VV, and VW to the first to third coils 20 respectively, a rotating magnetic field can be formed, and attraction between the plurality of magnetic bodies 18 and the plurality of permanent magnets 17 of the impeller 10. The impeller 10 can be rotated by the force and the repulsive force.

  Here, when the impeller 10 is rotating at the rated rotational speed, the attraction force between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b and the attraction force between the plurality of permanent magnets 17 and the plurality of magnetic bodies 18 are as follows. The blood chamber 7 is adapted to be balanced in the vicinity of the approximate center of the movable range of the impeller 10. For this reason, in any movable range of the impeller 10, the acting force due to the suction force to the impeller 10 is very small. As a result, the frictional resistance at the time of relative sliding between the impeller 10 and the housing 2 generated when the impeller 10 starts rotating can be reduced. Further, there is no damage (surface irregularities) on the inner wall of the impeller 10 and the housing 2 during relative sliding, and the impeller 10 easily floats from the housing 2 even when the dynamic pressure during low-speed rotation is small. It becomes the state of. Therefore, hemolysis does not occur due to relative sliding between the impeller 10 and the housing 2, and thrombus does not occur due to slight surface damage (unevenness) that occurs during relative sliding.

  A plurality of dynamic pressure grooves 21 are formed on the surface of the partition wall 6 facing the shroud 12 of the impeller 10, and a plurality of dynamic pressure grooves 22 are formed on the inner wall of the blood chamber 7 facing the shroud 11. When the rotational speed of the impeller 10 exceeds a predetermined rotational speed, a dynamic pressure bearing effect is generated between each of the dynamic pressure grooves 21 and 22 and the impeller 10. As a result, a drag force is generated from each of the dynamic pressure grooves 21 and 22 against the impeller 10, and the impeller 10 rotates in a non-contact state in the blood chamber 7.

  More specifically, as shown in FIG. 6, the plurality of dynamic pressure grooves 21 are formed in a size corresponding to the shroud 12 of the impeller 10. Each dynamic pressure groove 21 has one end on the periphery (circumference) of a circular portion slightly spaced from the center of the partition wall 6 and has a width up to the vicinity of the outer edge of the partition wall 6 in a spiral shape (in other words, curved). It extends to gradually spread. The plurality of dynamic pressure grooves 21 have substantially the same shape and are arranged at substantially the same interval. The dynamic pressure groove 21 is a recess, and the depth of the dynamic pressure groove 21 is preferably about 0.005 to 0.4 mm. The number of the dynamic pressure grooves 21 is preferably about 6 to 36.

  In FIG. 6, ten dynamic pressure grooves 21 are arranged at an equal angle with respect to the central axis of the impeller 10. Since the dynamic pressure groove 21 has a so-called inward spiral groove shape, when the impeller 10 rotates in the clockwise direction, the liquid pressure increases from the outer diameter portion to the inner diameter portion of the dynamic pressure groove 21. For this reason, a repulsive force is generated between the impeller 10 and the partition wall 6, and this becomes a dynamic pressure.

  Thus, due to the hydrodynamic bearing effect formed between the impeller 10 and the plurality of hydrodynamic grooves 21, the impeller 10 is separated from the partition wall 6 and rotates in a non-contact state. For this reason, a blood flow path is ensured between the impeller 10 and the partition 6, and the blood retention between both and the generation | occurrence | production of the thrombus resulting from it are prevented. Furthermore, in the normal state, the dynamic pressure groove 21 exerts a stirring action between the impeller 10 and the partition wall 6, so that it is possible to prevent partial blood retention between the two.

  Instead of providing the dynamic pressure groove 21 in the partition wall 6, the dynamic pressure groove 21 may be provided on the surface of the shroud 12 of the impeller 10.

  Further, the corner portion of the dynamic pressure groove 21 is preferably rounded so as to have an R of at least 0.05 mm. Thereby, generation | occurrence | production of hemolysis can be decreased more.

  Further, as shown in FIG. 7, the plurality of dynamic pressure grooves 22 are formed in a size corresponding to the shroud 11 of the impeller 10, similarly to the plurality of dynamic pressure grooves 21. Each dynamic pressure groove 22 has one end on the periphery (circumference) of a circular portion slightly spaced from the center of the inner wall of the blood chamber 7 and spirally (in other words, curved) on the inner wall of the blood chamber 7. It extends so that the width gradually increases to the vicinity of the outer edge. The plurality of dynamic pressure grooves 22 have substantially the same shape and are arranged at substantially the same interval. The dynamic pressure groove 22 is a recess, and the depth of the dynamic pressure groove 22 is preferably about 0.005 to 0.4 mm. The number of the dynamic pressure grooves 22 is preferably about 6 to 36. In FIG. 7, ten dynamic pressure grooves 22 are arranged at an equal angle with respect to the central axis of the impeller 10.

  Due to the hydrodynamic bearing effect formed between the impeller 10 and the plurality of hydrodynamic grooves 22, the impeller 10 is separated from the inner wall of the blood chamber 7 and rotates in a non-contact state. Moreover, when the pump part 1 receives an external impact or when the dynamic pressure by the dynamic pressure groove 21 becomes excessive, it is possible to prevent the impeller 10 from sticking to the inner wall of the blood chamber 7. The dynamic pressure generated by the dynamic pressure groove 21 and the dynamic pressure generated by the dynamic pressure groove 22 may be different.

  The dynamic pressure groove 22 may be provided not on the inner wall side of the blood chamber 7 but on the surface of the shroud 11 of the impeller 10. Further, the corners of the dynamic pressure grooves 22 are preferably rounded so as to have an R of at least 0.05 mm. Thereby, generation | occurrence | production of hemolysis can be decreased more.

  In addition, it is preferable that the impeller 10 rotates in a state where the gap between the shroud 12 of the impeller 10 and the partition wall 6 and the gap between the shroud 11 of the impeller 10 and the inner wall of the blood chamber 7 are substantially the same. When disturbance such as fluid force acting on the impeller 10 is large and one gap is narrowed, the dynamic pressure by the dynamic pressure groove on the narrowing side is made larger than the dynamic pressure by the other dynamic pressure groove, To make the dynamic pressure grooves 21 and 22 different in shape.

  6 and 7, each of the dynamic pressure grooves 21 and 22 has an inward spiral groove shape, but it is also possible to use dynamic pressure grooves 21 and 22 of other shapes. However, when blood is circulated, it is preferable to employ the inward spiral groove-shaped dynamic pressure grooves 21 and 22 that allow blood to flow smoothly.

  FIG. 11 shows the resultant force of the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b (abbreviated as between the permanent magnets 15 and 16 in FIG. 11) and the attractive force F2 between the permanent magnet 17 and the magnetic body 18. 6 is a diagram showing the force acting on the impeller 10 when the size of the impeller 10 is adjusted to be zero at a position P1 other than the central position of the movable range in the blood chamber 7 of the impeller 10. FIG. However, the rotation speed of the impeller 10 is kept at the rated value.

  That is, the floating position of the impeller 10 where the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b is set smaller than the attractive force F2 between the permanent magnet 17 and the magnetic body 18 and the resultant force thereof becomes zero. Suppose that it exists in the partition 6 side rather than the middle of an impeller movable range. The shapes of the dynamic pressure grooves 21 and 22 are the same.

  The horizontal axis in FIG. 11 indicates the position of the impeller 10 (the left side in the figure is the partition wall 6 side), and the vertical axis indicates the acting force on the impeller 10. When the acting force on the impeller 10 acts on the partition wall 6 side, the acting force is negative. The acting force on the impeller 10 includes an attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b, an attractive force F2 between the permanent magnet 17 and the magnetic body 18, a dynamic pressure F3 in the dynamic pressure groove 21, The dynamic pressure F4 of the dynamic pressure groove 22 and the resultant force “net force F5 acting on the impeller” are shown.

  As can be seen from FIG. 11, the floating position of the impeller 10 is largely deviated from the center position of the movable range of the impeller 10 at the position where the net force F5 acting on the impeller 10 becomes zero. As a result, the distance between the rotating impeller 10 and the partition wall 6 is narrowed, and the impeller 10 contacts the partition wall 6 even if a small disturbance force acts on the impeller 10.

  On the other hand, FIG. 12 shows that the magnitude of the resultant force of the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b and the attractive force F2 between the permanent magnet 17 and the magnetic body 18 is the blood chamber of the impeller 10. 7 is a diagram showing the force acting on the impeller 10 when it is adjusted to be zero at the center position P0 of the movable range in FIG. Also in this case, the rotational speed of the impeller 10 is kept at the rated value.

  That is, the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b and the attractive force F2 between the permanent magnet 17 and the magnetic body 18 are set to be substantially the same. Further, the shapes of the dynamic pressure grooves 21 and 22 are the same. In this case, since the net force F5 acting on the impeller 10 is zero at the center of the movable range, when no disturbance force acts on the impeller 10, the impeller 10 floats at the center position.

  As described above, the floating position of the impeller 10 is determined by the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b, the attractive force F2 between the permanent magnet 17 and the magnetic body 18, and the dynamic pressure when the impeller 10 rotates. It is determined by the balance with the dynamic pressures F3 and F4 generated in the grooves 21 and 22. By making F1 and F2 substantially the same and making the shape of the dynamic pressure grooves 21 and 22 the same, the impeller 10 can be floated at the substantially central portion of the blood chamber 7 when the impeller 10 rotates. As shown in FIGS. 3 and 4, the impeller 10 has a shape in which blades are formed between two disks. Therefore, two surfaces facing the inner wall of the housing 2 can have the same shape and the same size. Therefore, it is possible to provide the dynamic pressure grooves 21 and 22 having substantially the same dynamic pressure performance on both sides of the impeller 10.

  In this case, since the impeller 10 floats at the central position of the blood chamber 7, the impeller 10 is held at a position farthest from the inner wall of the housing 2. As a result, even if a disturbance force is applied to the impeller 10 when the impeller 10 is lifted and the floating position of the impeller 10 is changed, the possibility that the impeller 10 and the inner wall of the housing 2 come into contact with each other is reduced. The possibility of thrombus and hemolysis is also reduced.

  11 and 12, the two dynamic pressure grooves 21 and 22 have the same shape. However, the dynamic pressure grooves 21 and 22 have different shapes, and the dynamic pressure grooves 21 and 22 The pressure performance may be different. For example, when a disturbance in one direction always acts on the impeller 10 due to fluid force or the like during pumping, the performance of the dynamic pressure groove in the direction of the disturbance is made higher than the performance of the other dynamic pressure groove. Thus, the impeller 10 can be floated and rotated at the center position of the housing 2. As a result, the contact probability between the impeller 10 and the housing 2 can be kept low, and the stable flying performance of the impeller 10 can be obtained.

  Further, the negative support rigidity value in the axial direction of the impeller 10 constituted by the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b and the attractive force F2 between the permanent magnet 17 and the magnetic body 18 is obtained. The absolute value of Ka is the absolute value of the positive stiffness value in the radial direction, Kr, and the absolute value of the positive stiffness value obtained by the two dynamic pressure grooves 21 and 22 in the normal rotational speed region where the impeller 10 rotates is Kg. Then, it is preferable to satisfy the relationship of Kg> Ka + Kr.

  Specifically, when the absolute value Ka of the negative stiffness value in the axial direction is 20000 N / m and the absolute value Kr of the positive stiffness value in the radial direction is 10000 N / m, the rotation speed region where the impeller 10 normally rotates Thus, the absolute value Kg of the positive stiffness value obtained by the two dynamic pressure grooves 21 and 22 is set to a value exceeding 30000 N / m.

  Since the axial support rigidity of the impeller 10 is a value obtained by subtracting the negative rigidity due to the attractive force between the magnetic bodies from the rigidity caused by the dynamic pressure generated in the dynamic pressure grooves 21 and 22, it has a relationship of Kg> Ka + Kr. Thus, the support rigidity in the axial direction can be higher than the support rigidity in the radial direction of the impeller 10. By setting in this way, when a disturbance force acts on the impeller 10, the movement of the impeller 10 in the axial direction can be suppressed rather than the movement of the impeller 10 in the radial direction. The mechanical contact between the impeller 10 and the housing 2 can be avoided.

  In particular, since the dynamic pressure grooves 21 and 22 are recessed in a plane as shown in FIGS. 3, 6 and 7, the mechanical contact between the housing 2 and the impeller 10 is performed at this portion during the rotation of the impeller 10. If contact is made, scratches (surface irregularities) may occur on the surface of either or both of the impeller 10 and the inner wall of the housing 2, and if blood passes through this area, thrombus formation and hemolysis may occur. There was also. In order to prevent mechanical contact in the dynamic pressure grooves 21 and 22 and suppress thrombus and hemolysis, the effect of increasing the rigidity in the axial direction is higher than the rigidity in the radial direction.

  Further, when the impeller 10 is unbalanced, the impeller 10 swings during rotation. This swing is determined by the natural frequency determined by the mass of the impeller 10 and the support rigidity value of the impeller 10 and the rotational speed of the impeller 10. Maximum if matched.

In the pump unit 1, the support rigidity in the radial direction is smaller than the support rigidity in the axial direction of the impeller 10. Therefore, it is preferable to set the maximum rotational speed of the impeller 10 to be equal to or less than the natural frequency in the radial direction. Therefore, in order to prevent mechanical contact between the impeller 10 and the housing 2, the impeller is constituted by the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b and the attractive force F2 between the permanent magnet 17 and the magnetic body 18. When the radial stiffness value of 10 is Kr (N / m), the mass of the impeller 10 is m (kg), and the rotational speed of the impeller is ω (rad / s), ω <(Kr / m) ^0.5 It is preferable to satisfy the relationship.

  Specifically, when the mass of the impeller 10 is 0.03 kg and the radial rigidity value is 2000 N / m, the maximum rotation speed of the impeller 10 is set to 258 rad / s (2565 rpm) or less. Conversely, when the maximum rotational speed of the impeller 10 is set to 366 rad / s (3500 rpm), the radial rigidity is set to 5018 N / m or more.

  Furthermore, it is preferable to set the maximum rotational speed of the impeller 10 to 80% or less of ω. Specifically, when the mass of the impeller 10 is 0.03 kg and the radial rigidity value is 2000 N / m, the maximum rotational speed is set to 206.4 rad / s (1971 rpm) or less. Conversely, when the maximum rotational speed of the impeller 10 is desired to be 366 rad / s (3500 rpm), the radial rigidity value is set to 6279 N / m or more. By setting the maximum rotation speed of the impeller 10 in this way, contact between the impeller 10 and the housing 2 during rotation of the impeller 10 can be suppressed.

  Further, as shown in FIG. 13, the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b (abbreviated as between the permanent magnets 15 and 16 in FIG. 13) is the movement of the impeller 10 in the radial direction. It decreases with it. Similarly, the attractive force F2 between the permanent magnet 17 and the magnetic body 18 decreases as the impeller 10 moves in the radial direction.

  Since the impeller 10 is eccentric in the radial direction during the desired pump operation, the change amount ΔF1 of the suction force F1 with respect to the eccentric amount of the impeller 10 and the change amount ΔF2 of the suction force F2 with respect to the eccentric amount of the impeller 10 are different. The floating position of the impeller 10 at the eccentric position moves from the central position of the blood chamber 7. For this reason, if any one of the gap between the impeller 10 and the inner wall of the blood chamber 7 and the gap between the impeller 10 and the partition wall 6 is reduced and a disturbance is applied to the impeller 10, The inner wall of the blood chamber 7 or the partition wall 6 comes into contact.

  On the other hand, when the change amount ΔF1 of the suction force F1 and the change amount ΔF2 of the suction force F2 are equal, the floating position of the impeller 10 is maintained at the center position of the blood chamber 7 even if the impeller 10 is eccentric in the radial direction. . Therefore, even if a disturbance acts on the impeller 10, the possibility that the impeller 10 and the inner wall of the blood chamber 7 or the partition wall 6 are in contact with each other is low. Therefore, in the first embodiment, by adjusting the phase of the current flowing through the coil 20, ΔF1≈ΔF2, and even when the impeller 10 is eccentric in the radial direction, the floating position of the impeller 10 in the axial direction is set to the blood chamber 7. Keep in the center position.

  FIG. 14 is a block diagram illustrating a configuration of the controller 25 that controls the pump unit 1. In FIG. 14, the controller 25 includes an amplitude calculator 26, a comparator 27, a storage unit 28, a motor control circuit 29, and a power amplifier 30. The amplitude calculator 26 obtains the amplitude of the output signal of the magnetic sensor SE, obtains the flying position of the impeller 10 from the amplitude, and gives a signal indicating the flying position of the impeller 10 to the motor control circuit 29. The comparator 27 compares the output signals of the three magnetic sensors SE with the level of the reference voltage, detects the rotation state of the permanent magnet 17 based on the comparison result, and controls the rotation drive signal indicating the rotation state of the permanent magnet 17 by motor control. This is applied to the circuit 29. The storage unit 28 stores waveforms of output signals of the amplitude calculator 26 and the comparator 27 when the impeller 10 is rotating at a predetermined rotational speed at the center position of the movable range.

  The motor control circuit 29 outputs, for example, a 120-degree energization type three-phase control signal so that the waveforms of the output signals of the amplitude calculator 26 and the comparator 27 match the waveforms stored in the storage unit 28. The power amplifier 27 amplifies the three-phase control signal from the motor control circuit 29 to generate the three-phase voltages VU, VV, and VW shown in FIG. The three-phase voltages VU, VV, VW are applied to the first to third coils 20 described with reference to FIGS. Thereby, a three-phase alternating current flows through the first to third coils 20, and the impeller 10 rotates at a predetermined rotation speed at the center position of the movable range.

  When the impeller 10 is eccentric in the radial direction, the suction forces F1 and F2 are reduced, but the load current is increased to perform a predetermined pump operation, and the suction force F2 is increased. The attraction force F2 is adjusted by adjusting the phase of the current flowing through the coil 20.

  That is, the efficiency is maximized when the phase difference between the three-phase voltages VU, VV, VW and the output signals of the three magnetic sensors SE is a predetermined value. When the phase of the three-phase voltages VU, VV, VW is advanced with respect to the phase of the output signals of the three magnetic sensors SE, the attractive force F2 between the permanent magnet 17 and the magnetic body 18 decreases. Conversely, if the phase of the three-phase voltages VU, VV, VW is delayed with respect to the phases of the output signals of the three magnetic sensors SE, the attractive force F2 between the permanent magnet 17 and the magnetic body 18 increases.

  Therefore, when the impeller 10 is decentered in the radial direction and the axial position of the impeller 10 is shifted from the central position of the blood chamber 7, the phases of the three-phase voltages VU, VV, and VW are changed according to the position of the impeller 10. That is, by adjusting the phase of the three-phase alternating current flowing through the coil 20, the floating position of the impeller 10 can be returned to the central position of the blood chamber 7.

  The amount of change in the attractive force F2 that accompanies the phase adjustment of the three-phase voltages VU, VV, and VW varies depending on the device dimensions and output, but is about ± 1 N in the first embodiment. On the other hand, the amount of change in the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b due to the position variation of the impeller 10 is 1N or less. Therefore, it is possible to make F1≈F2 by adjusting the phases of the three-phase voltages VU, VV, and VW.

  In the first embodiment, the dynamic pressure grooves 21 and 22 are formed by balancing the attractive force between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b with the attractive force between the plurality of permanent magnets 50 and the plurality of permanent magnets 51. Since it is provided, the support rigidity in the axial direction of the impeller 10 can be increased. Further, since the two pairs of permanent magnets 15a, 16a and the permanent magnets 15b, 16b are provided in the radial direction of the impeller 10, the radial of the impeller 10 is compared with the case where only one pair of permanent magnets is provided in the radial direction of the impeller 10. The supporting rigidity in the direction can be increased. Further, the amount of change ΔF1 of the attractive force F1 between the permanent magnets 15a, 15b and the permanent magnets 16a, 16b when the impeller 10 is eccentric is substantially equal to the amount of change ΔF2 of the attractive force F2 between the permanent magnet 17 and the magnetic body 18. As a result, the support rigidity in the axial direction of the impeller 10 can be increased. Therefore, mechanical contact between the impeller 10 and the housing 2 can be reduced, and hemolysis and thrombus generation can be prevented.

  A diamond-like carbon (DLC) film may be formed on at least one of the inner wall surface of blood chamber 7, the surface of partition wall 6, and the surface of impeller 10. Thereby, the frictional force between the impeller 10 and the inner wall of the blood chamber 7 and the partition wall 6 can be reduced, and the impeller 10 can be smoothly rotated and started. Note that a fluorine-based resin film, a paraxylylene-based resin film, or the like may be formed instead of the diamond-like carbon film.

  FIG. 15 is a cross-sectional view showing a modified example of the first embodiment, and is a diagram to be compared with FIG. In this modification, nine coils 20 are divided into three groups of three, and the voltages VU, VV, and VW of FIG. 10 are applied to the first to third coils 20 of each group, respectively. The first magnetic sensor SE is disposed between the first and second coils 20 of the first group. The second magnetic sensor SE is disposed between the third coil 20 of the first group and the first coil 20 of the second group. The third magnetic sensor SE is disposed between the second and third coils 20 of the second group. Accordingly, the electrical angle between the first to third magnetic sensors SE is maintained at 120 degrees. Based on the output signals of the first to third magnetic sensors SE, it is possible to generate a three-phase control signal and detect the position of the impeller 10 in the axial direction. Further, since the mechanical angle between the first to third magnetic sensors SE is 80 degrees, it is possible to detect the flying posture of the rotating impeller 10.

  FIG. 16 is a cross-sectional view showing another modified example of the first embodiment, and is a figure to be compared with FIG. In this modification, nine coils 20 are divided into three groups of three, and three magnetic sensors SE are respectively disposed between three of the three groups. Therefore, since the mechanical angle between the three magnetic sensors SE is 120 degrees, the flying posture of the rotating impeller 10 can be easily calculated. The timing of flowing current through the nine coils 20 is calculated based on the output signal of any one of the three magnetic sensors SE.

  Further, the impeller 10 constituted by the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b and the attractive force F2 between the permanent magnet 17 and the magnetic body 18 is more movable than the negative stiffness value in the axial direction. When the rigidity due to the dynamic pressure of the pressure grooves 21 and 22 is increased, the impeller 10 and the housing 2 are not in contact with each other. Therefore, it is preferable to make this negative rigidity value as small as possible. Therefore, in order to keep the negative rigidity value small, it is preferable that the sizes of the facing surfaces of the permanent magnets 15a and 16a are made different and the sizes of the facing surfaces of the permanent magnets 15b and 16b are made different. For example, as shown in FIG. 17, by making the sizes of the permanent magnets 15a and 15b smaller than the permanent magnets 16a and 16b, respectively, the rate of change of the attractive force that changes depending on the distance between them, that is, the negative rigidity is kept small. This can prevent the impeller support rigidity from being lowered.

  FIG. 18 is a cross-sectional view showing still another modified example of the first embodiment, which is compared with FIG. In FIG. 18, in this modification, a magnetic body 35 is provided on the tip surface of each magnetic body 18 facing the permanent magnet 17. The area of the surface of the magnetic body 35 facing the permanent magnet 17 is larger than the area of the tip surface of the magnetic body 18. In this modified example, the attractive force of the magnetic bodies 18 and 35 with respect to the permanent magnet 17 can be increased, and the energy efficiency in the rotational drive of the impeller 10 can be increased.

  FIG. 19 is a cross-sectional view showing still another modified example of the first embodiment, and is a view compared with FIG. In FIG. 19, in this modification, the yoke 19 is replaced with the yoke 36, and the magnetic body 18 is replaced with the magnetic body 37. Each of the yoke 36 and the magnetic body 37 includes a plurality of steel plates stacked in the length direction of the rotation shaft of the impeller 10. In this modified example, the eddy current loss generated in the yoke 36 and the magnetic body 37 can be reduced, and the energy efficiency in the rotational drive of the impeller 10 can be increased.

  As shown in FIG. 20, the magnetic body 32 may be replaced with a magnetic body 38 including a plurality of steel plates stacked in the rotation direction of the impeller 10. Further, as shown in FIG. 21, the magnetic body 32 may be replaced with a magnetic body 39 including a plurality of steel plates stacked in the radial direction of the impeller 10. Even in these cases, the same effect as the modified example of FIG. 19 can be obtained.

  Moreover, you may form each of the yoke 19 and the magnetic body 18 of FIG. 3 with the powder of pure iron, soft iron, or silicon iron. In this case, the iron loss of the yoke 19 and the magnetic body 18 can be reduced, and the energy efficiency in the rotational drive of the impeller 10 can be improved.

  FIG. 22 is a cross-sectional view showing still another modification of the first embodiment, and is a view compared with FIG. In FIG. 22, in this modified example, the magnetic body 18 is removed. In this modified example, the magnitude of the resultant force of the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b and the attractive force F2 between the permanent magnet 17 and the yoke 19 is determined in the blood chamber 7 of the impeller 10. It is adjusted to be zero at the center position P0 of the movable range. Even in this modified example, the same effect as in the first embodiment can be obtained.

  Further, when the attractive force F2 between the permanent magnet 17 and the yoke 19 is smaller than the attractive force F1 between the permanent magnets 15a, 15b and the permanent magnets 16a, 16b, as shown in FIG. Alternatively, the magnetic body 40 may be disposed, the attractive force F3 of the magnetic body 40 and the permanent magnet 17 may be added, and the attractive force F1 and the attractive force F2 + F3 may be balanced at substantially the center of the movable range of the impeller 10. The magnetic body 40 may be a permanent magnet.

  Further, as shown in FIG. 24, a permanent magnet 41 is arranged at a position facing the magnetic body 40 of the impeller 10 to apply an attractive force F4 between the magnetic body 40 and the permanent magnet 41, and an attractive force F1 and an attractive force F2 + F3 + F4. May be balanced at substantially the center of the movable range of the impeller 10. Further, the magnetic body 41 may be a permanent magnet. When the magnetic body 40 is a permanent magnet, the permanent magnet 41 may be a magnetic body.

  25 (a) and 25 (b) are cross-sectional views showing still another modification of the first embodiment and are compared with FIGS. 5 (a) and 5 (b). FIG. 22A is a sectional view taken along line XXVA-XXVA in FIG. In this modification, the N pole of the permanent magnet 15a and the N pole of the permanent magnet 15b are provided in opposite directions, and the N pole of the permanent magnet 16a and the N pole of the permanent magnet 16b are provided in opposite directions. The S pole of the permanent magnet 15a and the N pole of the permanent magnet 16a face each other, and the N pole of the permanent magnet 15b and the S pole of the permanent magnet 16b face each other. Even in this modified example, the same effect as in the first embodiment can be obtained.

  Further, in the first embodiment, the case where the present invention is applied to a centrifugal blood pump apparatus using the magnetic sensor SE has been described. However, the present invention is a sensorless drive type centrifugal blood pump that does not use the magnetic sensor SE. It is also applicable to the device. In the sensorless driving method, phase information is obtained from the back electromotive force waveform, current waveform, and inductance change of the coil 20 that occur in the coil 20 as the permanent magnet 17 rotates, and the phase of the current that flows through the coil 20 based on the phase information. Make adjustments. In the case of using vector control, the same effect as the phase adjustment can be obtained by changing the magnitude of the d-axis current Id (excitation current) while leaving the q-axis current Iq (torque current) as it is. .

[Embodiment 2]
FIG. 26 is a cross-sectional view showing the configuration of the pump portion of the centrifugal blood pump apparatus according to Embodiment 2 of the present invention, and is a view compared with FIG. In FIG. 26, in this pump unit, a plurality of (for example, eight) permanent magnets 50 are embedded in the shroud 12 of the impeller 10 instead of the plurality of permanent magnets 17. The plurality of permanent magnets 50 are arranged along the same circle at equal angular intervals. In the motor chamber 8, a plurality (for example, eight) of permanent magnets 51 for attracting the plurality of permanent magnets 50 are provided. The plurality of permanent magnets 51 are arranged along the same circle at equal angular intervals so as to face the plurality of permanent magnets 50 of the impeller 10.

  The plurality of permanent magnets 51 are provided on the surface of the bowl-shaped rotor 52. A plurality of (for example, eight) permanent magnets 53 are provided at equal angular intervals inside the edge of the rotor 52. The plurality of permanent magnets 53 are arranged along the same circle at equal angular intervals so that adjacent magnetic poles are different from each other. In other words, the permanent magnets 53 with the north pole facing the inner side of the rotor 52 and the permanent magnets 53 with the south pole facing the inner side of the rotor 52 are alternately arranged along the same circle at equal angular intervals. .

  A central portion of the rotor 52 is rotatably supported on a central shaft 55 via a bearing 54, and the rotor 52 is provided to be rotatable along the partition wall 6. The central shaft 55 is erected at the center of the disk-shaped yoke 56. A plurality of (for example, nine) magnetic bodies 57 are provided at equiangular intervals around the central axis 55 on the surface of the yoke 56. The tips of the plurality of magnetic bodies 57 are disposed along the same circle so as to face the plurality of permanent magnets 53 of the rotor 52. A coil 58 is wound around each magnetic body 57. The plurality of permanent magnets 53, the plurality of magnetic bodies 57, and the plurality of coils 58 constitute a motor for rotating the rotor 52.

  For example, a voltage is applied to the nine coils 58 by a 120-degree conduction method. That is, nine coils 58 are grouped by three. The voltages VU, VV, and VW shown in FIG. 9 are applied to the first to third coils 58 of each group. Therefore, by applying the voltages VU, VV, and VW to the first to third coils 58, respectively, a rotating magnetic field can be formed, and attraction between the plurality of magnetic bodies 57 and the plurality of permanent magnets 53 of the rotor 52. The rotor 52 can be rotated by the force and the repulsive force. When the rotor 52 rotates, the impeller 10 rotates due to the attractive force between the plurality of permanent magnets 51 of the rotor 52 and the plurality of permanent magnets 50 of the impeller 10.

  Here, when the impeller 10 is rotating at the rated rotational speed, the attractive force between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b and the attractive force between the plurality of permanent magnets 50 and the plurality of permanent magnets 51 are as follows. The blood chamber 7 is adapted to be balanced in the vicinity of the approximate center of the movable range of the impeller 10. For this reason, in any movable range of the impeller 10, the acting force due to the suction force to the impeller 10 is very small. As a result, the frictional resistance at the time of relative sliding between the impeller 10 and the housing 2 generated when the impeller 10 starts rotating can be reduced. Further, there is no damage (surface irregularities) on the inner wall of the impeller 10 and the housing 2 during relative sliding, and the impeller 10 easily floats from the housing 2 even when the dynamic pressure during low-speed rotation is small. It becomes the state of.

  As in the first embodiment, a dynamic pressure groove 21 is formed on the surface of the partition wall 6 facing the shroud 12 of the impeller 10, and a dynamic pressure groove 22 is formed on the inner wall of the blood chamber 7 facing the shroud 11. ing. When the rotational speed of the impeller 10 exceeds a predetermined rotational speed, a dynamic pressure bearing effect is generated between each of the dynamic pressure grooves 21 and 22 and the impeller 10. As a result, a drag force is generated from each of the dynamic pressure grooves 21 and 22 against the impeller 10, and the impeller 10 rotates in a non-contact state in the blood chamber 7.

  Furthermore, in the second embodiment, as shown in FIG. 13, the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b decreases as the impeller 10 moves in the radial direction. Similarly, the attractive force F2 between the permanent magnets 50 and 51 decreases as the impeller 10 moves in the radial direction.

  Since the impeller 10 is eccentric in the radial direction during the desired pump operation, the change amount ΔF1 of the suction force F1 with respect to the eccentric amount of the impeller 10 and the change amount ΔF2 of the suction force F2 with respect to the eccentric amount of the impeller 10 are different. The floating position of the impeller 10 at the eccentric position moves from the central position of the blood chamber 7. For this reason, if any one of the gap between the impeller 10 and the inner wall of the blood chamber 7 and the gap between the impeller 10 and the partition wall 6 is reduced and a disturbance is applied to the impeller 10, The inner wall of the blood chamber 7 or the partition wall 6 comes into contact.

  On the other hand, when the change amount ΔF1 of the suction force F1 and the change amount ΔF2 of the suction force F2 are equal, the floating position of the impeller 10 is maintained at the center position of the blood chamber 7 even if the impeller 10 is eccentric in the radial direction. . Therefore, even if a disturbance acts on the impeller 10, the possibility that the impeller 10 and the inner wall of the blood chamber 7 or the partition wall 6 are in contact with each other is low. Therefore, in the second embodiment, by adjusting the diameters of the permanent magnets 50 and 51, ΔF1≈ΔF2, and even when the impeller 10 is eccentric in the radial direction, the floating position of the impeller 10 in the axial direction is set to the blood chamber 7. Keep in the center position.

  FIGS. 27A and 27B are diagrams showing the overlapping state of the permanent magnets 50 and 51 when the impeller 10 is eccentric, and FIG. 27A is a case where the diameters of the permanent magnets 50 and 51 are relatively large. FIG. 27A shows a case where the diameters of the permanent magnets 50 and 51 are relatively small. FIG. 28 is a diagram showing the relationship between the amount of eccentricity of the impeller 10 and the suction force F2.

  27A and 27B, the rotation center of the plurality of permanent magnets 50 is O1, and the rotation center of the plurality of permanent magnets 51 is O2. When the impeller 10 is not eccentric, the rotation centers O1 and O2 coincide when viewed from a direction perpendicular to the impeller 10. Here, as a result of the eccentricity of the impeller 10, it is assumed that the rotation centers O1 and O2 are shifted by a certain distance d.

  In the case of the centrifugal blood pump shown in FIG. 26, when the rotor 52 rotates, an angular deviation occurs between the permanent magnets 50 and 51, thereby generating a rotational torque in the impeller 10. When the impeller 10 is not eccentric, the opposing areas (overlapping areas) of the plurality of sets of permanent magnets 50 and 51 are the same. When the impeller 10 is decentered, as shown in FIGS. 27A and 27B, the opposing areas of the permanent magnets 50 and 51 increase or decrease depending on the set, but the sum of the opposing areas of the plural sets of permanent magnets 50 and 51 is the impeller 10. Is reduced compared to the case where is not eccentric. When the impeller 10 is eccentric, the amount of change in the sum of the opposing areas of the plurality of sets of permanent magnets 50 and 51 increases as the diameter of the permanent magnets 50 and 51 decreases.

  Further, the attractive force F <b> 2 between the plurality of sets of permanent magnets 50, 51 varies according to the sum of the opposing areas of the plurality of sets of permanent magnets 50, 51. For this reason, as shown in FIG. 28, the suction force F <b> 2 decreases according to the radial displacement of the impeller 10. Further, the displacement amount ΔF2A of the attractive force F2 when the diameters of the permanent magnets 50 and 51 are relatively large is smaller than the displacement amount ΔF2B of the attractive force F2 when the diameters of the permanent magnets 50 and 51 are relatively small. On the other hand, if the dimensions of the permanent magnets 15a and 15b and the permanent magnets 16a and 16b are determined, the amount of change ΔF1 of the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b is constant. Therefore, by adjusting the diameters of the permanent magnets 50 and 51, the change amount ΔF1 of the attractive force F1 and the change amount ΔF2 of the attractive force F2 can be substantially matched.

  Further, the amount of deviation between the center point of the permanent magnet 50 and the center point of the permanent magnet 51 is the sum of the amount of eccentricity of the impeller 10 and the amount of angular deviation in the circumferential direction in which a desired rotational torque is generated. The amount of deviation between the rotation center O1 and the rotation center O2 of the permanent magnet 51 is the same as the amount of eccentricity of the impeller 10. On the other hand, the amount of deviation between the rotation centers of the permanent magnets 15 a and 15 b and the rotation centers of the permanent magnets 16 a and 16 b is equal to the eccentricity of the impeller 10.

  Therefore, in order to make the change amount ΔF1 of the attractive force F1 equal to the change amount ΔF2 of the attractive force F2, positive support in the radial direction of the magnetic coupling portion constituted by the permanent magnets 15a and 15b and the permanent magnets 16a and 16b is provided. The absolute value K1 of the stiffness value and the absolute value K2 of the positive support stiffness value in the radial direction of the magnetic coupling portion formed by the plurality of sets of permanent magnets 50 and 51 should maintain the relationship of K1−K2> 0. Is desirable.

  In the second embodiment, the attractive pressure between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b and the attractive force between the plurality of permanent magnets 50 and the plurality of permanent magnets 51 are balanced, and the dynamic pressure grooves 21 and 22 are formed. Since it is provided, the floating position of the impeller 10 can always be maintained at a substantially central position in the housing 2. Further, since the two pairs of permanent magnets 15a, 16a and the permanent magnets 15b, 16b are provided in the radial direction of the impeller 10, the radial of the impeller 10 is compared with the case where only one pair of permanent magnets is provided in the radial direction of the impeller 10. The supporting rigidity in the direction can be increased. Furthermore, the amount of change ΔF1 of the attractive force F1 between the permanent magnets 15a, 15b and the permanent magnets 16a, 16b when the impeller 10 is eccentric and the amount of change ΔF2 of the attractive force F2 between the plurality of sets of permanent magnets 50, 51 are approximately shown. Since they are matched, the floating position of the impeller 10 can always be maintained at a substantially central position in the housing 2. Therefore, mechanical contact between the impeller 10 and the housing 2 can be reduced, and hemolysis and thrombus generation can be prevented.

  In the second embodiment, the diameters of the permanent magnets 50 and 51 are adjusted and the change amount ΔF2 of the attractive force F2 is adjusted so that ΔF1≈ΔF2, but the permanent magnets 15a and 15b and the permanent magnets 16a and 16b. May be adjusted so that ΔF1≈ΔF2 by adjusting the change amount ΔF1 of the suction force F1.

  FIGS. 29 (a) and 29 (b) are diagrams showing a modification of the second embodiment, and are diagrams showing the overlapping state of the permanent magnets 15a and 15b and the permanent magnets 16a and 16b when the impeller 10 is eccentric. It is. 27A shows a case where the magnetic poles of the permanent magnets 15a and 15b (permanent magnets 16a and 16b) are directed in the same direction, and FIG. 27B shows the permanent magnets 15a and 15b (permanent magnets 16a and 16b). The case where the magnetic poles are directed in opposite directions is shown. FIG. 28 is a diagram showing the relationship between the amount of eccentricity of the impeller 10 and the suction force F1.

  29 (a) and 29 (b), the rotation center of the permanent magnets 15a and 15b is O1, and the rotation center O2 of the permanent magnets 16a and 16b. When the impeller 10 is not eccentric, the rotation centers O1 and O2 coincide when viewed from a direction perpendicular to the impeller 10. Here, as a result of the eccentricity of the impeller 10, it is assumed that the rotation centers O1 and O2 are shifted by a certain distance d.

  When the impeller 10 is eccentric, as shown in FIGS. 29A to 29D, the facing areas of the permanent magnets 15a and 16a, 15b and 16b are reduced as compared with the case where the impeller 10 is not eccentric. Further, the attractive force F1 between the permanent magnets 15a and 15b and the permanent magnets 16a and 16b varies depending on the facing area of the permanent magnets 15a and 16a, 15b and 16b. Further, when the impeller 10 is eccentric, in the case of FIGS. 29 (a) and 29 (b), an attractive force is generated between the permanent magnets 15a and 16b, 15b and 16a, whereas FIGS. 29 (c) and 29 (d). In this case, a repulsive force is generated between the permanent magnets 15a and 16b, and 15b and 16a. For this reason, as shown in FIG. 30, the suction force F1 decreases in accordance with the radial displacement of the impeller 10, and the displacement amount ΔF1A in the case of FIGS. In the case of d), the displacement amount ΔF1B is larger.

  In this modified example, the amount of change ΔF1 of the attractive force F1 is obtained by arranging the magnetic poles of the permanent magnets 15a and 15b and the permanent magnets 16a and 16b as shown in FIGS. 29 (a) (b) or 29 (c) (d). Then, the amount of change ΔF2 of the suction force F2 is adjusted by the method shown in the second embodiment. Even in this modified example, the same effect as in the second embodiment can be obtained.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Pump part, 2 Housing, 3 Main-body part, 4 Blood inflow port, 5 Blood outflow port, 6 Bulkhead, 7 Blood chamber, 8 Motor room, 10 Impeller, 10a Through-hole, 11,12 Shroud, 13 vane, 14 Blood passage 15a, 15b, 16a, 16b, 17, 41, 50, 51, 53 Permanent magnet, 18, 35, 37-40, 57 Magnetic body, 19, 31, 56 yoke, 20, 58 coil, 21, 22 Pressure groove, 25 controller, 26 amplitude calculator, 27 comparator, 28 storage unit, 29 motor control circuit, 30 power amplifier, 52 rotor, 54 bearing, 55 central axis, SE magnetic sensor.

Claims (8)

A housing including first and second chambers partitioned by a partition; an impeller which is rotatably provided along the partition in the first chamber, and sends liquid by centrifugal force during rotation; and the second In a centrifugal pump device provided with a drive means provided in a room and rotating the impeller through the partition wall,
A first magnetic body provided on one surface of the impeller;
A second magnetic body that is provided on an inner wall of the first chamber facing one surface of the impeller and that attracts the first magnetic body;
A third magnetic body provided on the other surface of the impeller,
During the rotation of the impeller, the first attraction force between the first and second magnetic bodies and the second attraction force between the third magnetic body and the driving means are in the first chamber. Balance at the approximate center of the movable range of the impeller,
The change amount of the first suction force with respect to the eccentric amount of the impeller in the radial direction is substantially equal to the change amount of the second suction force with respect to the eccentric amount of the impeller in the radial direction,
A first dynamic pressure groove is formed on one surface of the impeller or an inner wall of the first chamber facing the impeller, and a second dynamic pressure groove is formed on the other surface of the impeller or the partition wall facing the impeller. A centrifugal pump device characterized by that. The driving means includes
A rotor provided rotatably in the second chamber along the partition;
A fourth magnetic body provided on the rotor and attracting the third magnetic body;
The centrifugal pump device according to claim 1, further comprising a motor that rotates the rotor.   The absolute value of the positive support rigidity value in the radial direction of the magnetic coupling portion constituted by the first and second magnetic bodies is the radial value of the magnetic coupling portion constituted by the third and fourth magnetic bodies. The centrifugal pump device according to claim 2, wherein the centrifugal pump device is larger than an absolute value of a positive support rigidity value in a direction. The third magnetic body includes a plurality of magnets arranged along the same circle such that adjacent magnetic poles are different from each other,
2. The centrifugal pump device according to claim 1, wherein the driving unit includes a plurality of coils provided to face the plurality of magnets and generate a rotating magnetic field. The third magnetic body includes a plurality of magnets arranged along the same circle such that adjacent magnetic poles are different from each other,
The driving means includes
A plurality of fourth magnetic bodies provided facing the plurality of magnets;
And a plurality of coils each provided corresponding to the plurality of fourth magnetic bodies, each wound around a corresponding fourth magnetic body, and generating a rotating magnetic field. Item 2. The centrifugal pump device according to Item 1.   The centrifugal pump device according to claim 4 or 5, wherein the second suction force is adjusted by changing a phase of a current flowing through the plurality of coils. Furthermore, the magnetic sensor provided in the second chamber facing the plurality of magnets,
The centrifugal pump device according to claim 6, wherein a phase of a current flowing through the plurality of coils is changed based on an output signal of the magnetic sensor. The liquid is blood;
The centrifugal pump device according to any one of claims 1 to 7, wherein the centrifugal pump device is used for circulating the blood.

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