JP4456857B2 - Centrifugal blood pump device - Google Patents

Description

The present invention relates to a centrifugal blood pump device for feeding medical fluid such as blood.

Recently, an example of using a centrifugal blood pump for extracorporeal blood circulation in an oxygenator is increasing. Centrifugal pumps use a system that transmits driving torque from an external motor using magnetic coupling by completely eliminating physical communication between the outside and the blood chamber in the pump and preventing invasion of bacteria. Is used.
As such a centrifugal blood pump, the present applicant has proposed the one shown in Japanese Patent Laid-Open No. 9-206372.
The centrifugal blood pump device disclosed in this publication includes a housing having a blood inflow port and a blood outflow port, and a centrifugal blood pump having an impeller that rotates in the housing and feeds blood by centrifugal force during rotation. And a non-controllable magnetic bearing component for the impeller (impeller rotational torque generator) and a controllable magnetic bearing component for the impeller (impeller position controller). The impeller rotates while being held at a predetermined position in the housing by the action of the control type magnetic bearing component. Further, the impeller has a large number of dynamic pressure grooves formed on the bottom surface (lower surface). Since this dynamic pressure groove is provided, it is attracted to the impeller rotational torque generating part side when the impeller position control part is not operated (in other words, when the electromagnet operation is stopped), but is formed between the dynamic pressure groove and the inner surface of the housing. Due to the hydrodynamic bearing effect, it is slightly separated from the inner surface of the housing and rotates in a non-contact state.
JP-A-9-206372

The centrifugal blood pump apparatus described above has an effective effect as a so-called magnetic levitation type. The dynamic pressure groove provided in the above-described pump device stops the impeller position control when the control type magnetic bearing component (impeller position control unit) for the impeller malfunctions, that is, operates the electromagnet that attracts the impeller. This dynamic pressure groove is not used during normal rotation. At the time of rotation using only the dynamic pressure groove, hemolysis or the like may occur particularly in a low rotation speed state. Further, because of magnetic levitation, it is necessary to provide an impeller position sensor, and there is a limit to downsizing of the apparatus, and furthermore, electric power for magnetic levitation of the impeller is also required.
Therefore, an object of the present invention is not a magnetic levitation type centrifugal blood pump, but a centrifugal blood pump device that substantially rotates the impeller in a non-contact state using a so-called dynamic pressure groove. An object of the present invention is to provide a centrifugal blood pump device that can be miniaturized by eliminating the need for a position sensor, and that can secure the distance between the impeller and the housing to reduce the occurrence of hemolysis.

What achieves the above object is as follows.
(1) Centrifugal pump unit having a housing having a liquid inflow port and a liquid outflow port, an impeller that includes a first magnetic body therein, rotates inside the housing, and feeds liquid by centrifugal force during rotation A rotor including a magnet for attracting the first magnetic body of the impeller of the centrifugal pump unit, an impeller rotational torque generating unit including a motor for rotating the rotor, and an inner surface of the housing on the rotor side or the impeller A centrifugal blood pump device provided with a dynamic pressure groove provided on the rotor side surface of the rotor, wherein an impeller rotates in a non-contact state by the dynamic pressure groove with respect to the housing, wherein the centrifugal blood pump device are those without a position sensor for the impeller, and the first magnetic body or provided separately et al with the first magnetic member of said impeller The second magnetic body is sucked in a direction opposite to the direction of suction by the magnet of the rotor, an electromagnet for assisting the floating of the impeller, a control mechanism for controlling the impeller rotational torque generating unit and the electromagnets, The control mechanism includes an impeller rotational torque generation unit current monitoring function, and controls the electromagnet using a current value detected by the monitoring function. Further, the control mechanism controls the impeller by the electromagnet. A rotation start state control function for starting rotation by the impeller rotation torque generating unit in a state of being sucked with a force equal to or greater than a predetermined value, and an impeller for reducing the suction force from the predetermined value after starting rotation by the impeller rotation torque generating unit A centrifugal blood pump apparatus having a control function after rotation of a rotational torque generator .
(2) The first magnetic body included in the impeller and the magnet included in the rotor for attracting the first magnetic body are both a plurality of permanent magnets, and the plurality of permanent magnets are substantially on the same circumference. In addition, the permanent magnet provided in the impeller and the permanent magnet provided in the rotor are arranged on the circumference facing each other and have opposite polarities. The centrifugal blood pump device according to (1) above.

Moreover, what achieves the said objective is as follows.
(3) Centrifugal pump unit having a housing having a liquid inflow port and a liquid outflow port, an impeller that includes a first magnetic body therein, rotates in the housing, and feeds liquid by centrifugal force during rotation. An impeller rotational torque generating unit including a plurality of stator coils arranged on the circumference for attracting the first magnetic body of the impeller of the centrifugal pump unit and rotating the impeller, and the stator coil side A centrifugal blood pump device including a dynamic pressure groove provided on an inner surface of the housing or a surface on the stator coil side of the impeller, and the impeller rotates in a non-contact state by the dynamic pressure groove with respect to the housing. the centrifugal blood pump device is one without a position sensor for the impeller, and said first of said impeller An electromagnet for attracting the second magnetic body provided separately from the first magnetic body or the second magnetic body in a direction opposite to the attraction direction by the stator coil, and assisting the impeller to float, and the impeller rotational torque A control mechanism for controlling the generator and the electromagnet, the control mechanism has an impeller rotation torque generator current monitoring function, and controls the electromagnet using a current value detected by the monitoring function; The control mechanism further includes a rotation start state control function for starting rotation by the impeller rotation torque generation unit in a state where the impeller is attracted by the electromagnet with a force equal to or greater than a predetermined value, and rotation by the impeller rotation torque generation unit. After starting, the impeller rotational torque generating unit has a post-rotation control function that lowers the suction force from the predetermined value. That the centrifugal blood pump apparatus.
(4) The centrifugal blood pump device includes a control mechanism for controlling the impeller rotational torque generation unit and the electromagnet, and the control mechanism uses the electromagnet according to the number of rotations of the impeller rotational torque generation unit. The centrifugal blood pump device according to any one of (1) to (3), wherein the centrifugal blood pump device has a function of changing a suction force of the impeller.
(5) The control mechanism has a function of maintaining a substantially constant distance between the impeller and the housing by changing an attraction force of the impeller by the electromagnet according to the number of rotations of the impeller rotational torque generating unit. The centrifugal blood pump device according to (4), which is provided.

( 6 ) The centrifugal type according to any one of (1) to ( 5 ), wherein the dynamic pressure groove is chamfered so that a corner portion of the dynamic pressure groove has an R of at least 0.05 mm or more. Blood pump device.
( 7 ) The centrifugal blood pump device according to any one of (1) to ( 6 ), wherein the second dynamic pressure groove provided on the inner surface of the electromagnet housing or the surface of the impeller on the electromagnet side is provided. Centrifugal blood pump device.
( 8 ) The centrifugal blood pump device according to ( 7 ), wherein the second dynamic pressure groove is chamfered so that a corner portion of the dynamic pressure groove has an R of at least 0.05 mm.

The centrifugal blood pump device of the present invention includes a housing having a liquid inflow port and a liquid outflow port, and a first magnetic body therein, and rotates within the housing, and the liquid is fed by centrifugal force during rotation. A centrifugal pump unit having an impeller to perform, a rotor including a magnet for attracting a first magnetic body of the impeller of the centrifugal pump unit, an impeller rotational torque generating unit including a motor for rotating the rotor, and the rotor A centrifugal blood pump device including a dynamic pressure groove provided on an inner surface of the housing or the rotor side surface of the impeller, wherein the impeller rotates in a non-contact state by the dynamic pressure groove with respect to the housing. The centrifugal blood pump device uses the first magnetic body of the impeller or the second magnetic body provided separately from the first magnetic body as a magnet of the rotor. According suction direction by suction in the opposite direction, and includes an electromagnet to assist in floating of the impeller.
For this reason, even a centrifugal blood pump device that uses a so-called dynamic pressure groove to rotate the impeller in a substantially non-contact state with respect to the housing effectively assists the impeller to rise and increases the distance between the housings. Can be ensured, and the occurrence of hemolysis can be reduced. Further, as compared with the magnetic levitation type centrifugal blood pump device, a position sensor is not required, and the size and power consumption can be reduced.

The centrifugal blood pump device according to the present invention further includes a housing having a liquid inflow port and a liquid outflow port, and a first magnetic body therein. The centrifugal blood pump device rotates within the housing and draws liquid by centrifugal force during rotation. An impeller rotation having a centrifugal pump section having an impeller for feeding liquid, and a plurality of stator coils arranged on the circumference for attracting the first magnetic body of the impeller of the centrifugal pump section and rotating the impeller A torque generating portion and a dynamic pressure groove provided on the inner surface of the housing on the stator coil side or the stator coil side surface of the impeller, and the impeller is rotated in a non-contact state by the dynamic pressure groove with respect to the housing A centrifugal blood pump device, wherein the centrifugal blood pump device is the first magnetic body or the first magnetic body of the impeller. When provided with an electromagnet for the second magnetic body is attracted to the opposite direction to the suction direction by the stator coil, assists the flying of said impeller provided separately.
For this reason, even a centrifugal blood pump device that uses a so-called dynamic pressure groove to rotate the impeller in a substantially non-contact state with respect to the housing effectively assists the impeller to rise and increases the distance between the housings. Can be ensured, and the occurrence of hemolysis can be reduced. Further, as compared with the magnetic levitation type centrifugal blood pump device, a position sensor is not required, and the size and power consumption can be reduced.

Further, the centrifugal blood pump device includes a control mechanism for controlling the motor and the electromagnet, and the control mechanism is controlled by the rotational speed of the impeller rotational torque generator (in other words, by the impeller rotational torque generator). As long as it has a function of changing the attraction force of the impeller by the electromagnet according to the generated rotation speed), it is possible to secure a distance with less hemolysis between the impeller and the housing in power saving. it can.
The control mechanism has a function of maintaining a substantially constant distance between the impeller and the housing by changing an attraction force of the impeller by the electromagnet in accordance with the rotation speed of the impeller rotational torque generating unit. If this is the case, it is possible to secure a distance with less hemolysis between the impeller and the housing for power saving.
Further, if the control mechanism has a rotation start state control function for starting rotation of the impeller rotation torque generation unit in a state where the impeller is attracted by the electromagnet with a force of a predetermined value or more, The impeller can be favorably started to rotate, and hemolysis of blood located between the impeller and the housing in the initial stage of rotation can be prevented.

In addition, the control mechanism includes a rotation start state control function for starting rotation of the impeller rotation torque generation unit in a state where the impeller is attracted by the electromagnet with a suction force of a predetermined value or more, and an impeller rotation torque generation unit If the impeller rotational torque generating unit has a post-rotation control function that lowers the suction force from the predetermined value after the start of rotation, the impeller starts rotating well, and the blood located between the impeller and the housing at the initial stage of rotation In addition to preventing hemolysis, it is possible to ensure a small distance between the impeller and the housing in terms of power saving.
In addition, the centrifugal blood pump device has a second dynamic pressure groove provided on the inner surface of the housing on the electromagnet side or the surface on the electromagnet side of the impeller. When the dynamic pressure by the dynamic pressure groove 38 becomes excessive, the impeller is prevented from sticking to the inner surface of the electromagnet side of the housing.

FIG. 1 is a block diagram of an embodiment including a control mechanism of a centrifugal blood pump apparatus of the present invention. FIG. 2 is a front view of an example of a centrifugal blood pump device used in the centrifugal blood pump device of the present invention. FIG. 3 is a plan view of the centrifugal blood pump apparatus shown in FIG. FIG. 4 is a longitudinal sectional view of the centrifugal blood pump apparatus of the embodiment shown in FIG. 5 is a cross-sectional view of the centrifugal blood pump device of FIG. 2 taken along line AA. 6 is a cross-sectional view showing a state where the impeller is removed from the cross-sectional view taken along the line AA of the centrifugal blood pump device of FIG.
The centrifugal blood pump device 1 according to the present invention includes a housing 20 having a liquid inflow port 22 and a liquid outflow port 23, and a first magnetic body 25 therein. The centrifugal blood pump 1 rotates in the housing 20 and rotates during the rotation. The rotor 31 including the centrifugal pump unit 2 having the impeller 21 for feeding the liquid, the magnet 33 for attracting the first magnetic body 25 of the impeller 21 of the centrifugal pump unit 2, and the motor 34 for rotating the rotor 31. And a dynamic pressure groove 38 provided on the inner surface of the housing 20 on the rotor 31 side or the surface on the rotor 31 side of the impeller 21. The impeller 21 is provided to the housing 20 by the dynamic pressure groove 38. Is a centrifugal blood pump device that rotates in a non-contact state. The centrifugal blood pump device 1 sucks the first magnetic body 25 of the impeller 21 or the second magnetic body 28 provided separately from the first magnetic body 25 in the direction opposite to the suction direction by the magnet 33 of the rotor 31. The electromagnet 41 for assisting the floating of the impeller 21 is provided.

The centrifugal blood pump device 1 is not magnetically levitated, but rotates the impeller in a substantially non-contact state with respect to the housing by a dynamic pressure groove, and does not require a position sensor for the impeller. Can be reduced in size. Furthermore, since the electromagnet 41 for assisting the floating of the impeller 21 is provided, the distance between the housing having the dynamic pressure groove and the impeller can be secured, the generation of hemolysis can be reduced, and The electromagnet is low in power consumption because it only assists the floating of the impeller.
As shown in FIGS. 2 to 6, the centrifugal blood pump apparatus 1 of this embodiment includes a housing 20 having a blood inflow port 22 and a blood outflow port 23, a rotation within the housing 20, and a centrifugal force during rotation. A centrifugal blood pump unit 2 having an impeller 21 for feeding blood, an impeller rotational torque generating unit 3 for the impeller 21, and an auxiliary suction control unit 4 for the impeller 21 are provided.

As shown in FIG. 4, the impeller 21 rotates without contacting the inner surface of the housing due to the pressure generated by the dynamic pressure groove during rotation. In particular, in this pump device 1, since the impeller is attracted in the direction opposite to the rotor by the electromagnet, it rotates in a state further separated from the distance between the impeller and the housing obtained by a normal dynamic pressure groove.
The housing 20 includes a blood inflow port 22 and a blood outflow port 23, and is formed of a nonmagnetic material. A blood chamber 24 communicating with the blood inflow port 22 and the blood outflow port 23 is formed in the housing 20. An impeller 21 is accommodated in the housing 20. The blood inflow port 22 is provided so as to protrude substantially vertically from the vicinity of the center of the upper surface of the housing 20. As shown in FIGS. 3 and 5, the blood outflow port 23 is provided so as to protrude in a tangential direction from the side surface of the housing 20 formed in a substantially cylindrical shape.

As shown in FIG. 5, a disc-like impeller 21 having a through-hole at the center is housed in a blood chamber 24 formed in the housing 20. As shown in FIG. 4, the impeller 21 is formed between a donut plate-like member (lower shroud) 27 that forms a lower surface, and a donut plate-like member (upper shroud) 28 that opens at the center that forms an upper surface. A plurality of (for example, seven) vanes 18. A plurality (seven) blood passages 26 partitioned by the adjacent vanes 18 are formed between the lower shroud and the upper shroud. As shown in FIG. 5, the blood passage 26 communicates with the central opening of the impeller 21, starts from the central opening of the impeller 21, and extends so that the width gradually increases to the outer peripheral edge. In other words, the vane 18 is formed between the adjacent blood passages 26. In this embodiment, each blood passage 26 and each vane 18 are provided at equal angular intervals and in substantially the same shape.
As shown in FIG. 4, the impeller 21 has a plurality of (for example, 14 to 24) first magnetic bodies 25 (permanent magnets, driven magnets) embedded therein. In this embodiment, the first magnetic body 25 is embedded in the lower shroud 27. The embedded magnetic body 25 (permanent magnet) attracts the impeller 21 to the side opposite to the blood inflow port 22 by a permanent magnet 33 provided on the rotor 31 of the impeller rotational torque generating unit 3 described later, and is coupled to the rotor. And the rotational torque is provided to transmit from the impeller rotational torque generating section.

Further, by embedding a certain number of magnetic bodies 25 as in this embodiment, sufficient magnetic coupling with the rotor 31 described later can be ensured. The shape of the magnetic body 25 (permanent magnet) is preferably circular. Alternatively, a ring-shaped magnet may be polarized into multiple poles (for example, 24 poles), in other words, a plurality of small magnets may be arranged in a ring shape so that the magnetic poles are alternately or the same.
Further, the impeller 21 includes a second magnetic body 28 provided in the upper shroud itself or in the upper shroud. In this embodiment, the entire upper shroud is formed of the magnetic body 28. The magnetic body 28 is provided to attract the impeller 21 to the side opposite to the rotor 31, in other words, to the blood inflow port 22 side by the electromagnet 41 of the impeller auxiliary suction portion. As the magnetic body 28, magnetic stainless steel or the like is used.

Since the impeller 21 is attracted to the rotor 31 side and the impeller 21 is attracted in the opposite direction to the rotor 31 by the electromagnet 41, the impeller 21 is in a non-contact state that is further separated than the distance between the impeller and the housing obtained by a normal dynamic pressure groove. The inside of the housing 20 is rotated.
As shown in FIG. 4, the impeller rotational torque generating unit 3 includes a rotor 31 housed in the housing 20 and a motor 34 for rotating the rotor 31. The rotor 31 includes a plurality of permanent magnets 33 provided on the surface on the blood pump unit 2 side. The center of the rotor 31 is fixed to the rotating shaft of the motor 34. The permanent magnets 33 are provided in plural and at equal angles so as to correspond to the arrangement form (number and arrangement position) of the permanent magnets 25 of the impeller 21.

Further, in the coupling of the permanent magnet between the impeller and the motor, it is preferable to arrange the permanent magnet so that an attractive force is always generated between the impeller and the motor even if the coupling is released due to an external force and the impeller and the motor are stepped out. . By doing so, even if the coupling is disengaged and the impeller and the motor are stepped out, the coupling is easily restored because the suction force is generated between them.
For example, as shown in FIG. 8, the first magnetic body included in the impeller 21 and the magnet included in the rotor 31 for attracting the first magnetic body are both a plurality of permanent magnets 25 and 33 and a plurality of permanent magnets. The magnets 25 and 33 are arranged so as to have the same polarity on substantially the same circumference. Further, it is conceivable that the permanent magnet 25 provided in the impeller 21 and the permanent magnet 33 provided in the rotor 31 are arranged on the circumferences facing each other and have opposite polarities. That is, the permanent magnet 25 provided in the impeller 21 and the permanent magnet 33 provided in the rotor 31 for attracting the permanent magnet 25 have opposite polarities of the permanent magnets arranged on the circumferences facing each other, and in the impeller and The roller has the same polarity on the circumference.

  Specifically, as shown in FIG. 8, a plurality of permanent magnets 25 a (for example, N poles) having the same polarity are arranged on the same circumference on the impeller 21. The rotor 31 is provided with a plurality of permanent magnets 33a (for example, S poles) having the same polarity and different polarity from the permanent magnet 25a so as to correspond to the permanent magnet 25a provided on the impeller. It arrange | positions on the circumference which becomes the diameter substantially the same as the made circumference. The plurality of permanent magnets 25 a are preferably arranged so as to be equiangular with respect to the central axis of the impeller 21. The plurality of permanent magnets 33a are preferably arranged so as to be equiangular with respect to the central axis of the rotor 31. Moreover, it is preferable that the arrangement angle of the plurality of permanent magnets 25a and the arrangement angle of the plurality of permanent magnets 33a are the same or the other arrangement angle is an integral multiple of one arrangement angle.

  Further, as shown in FIG. 8, the impeller 21 has a permanent magnet 25b (for example, an S pole) having the same polarity and a different polarity from the permanent magnet 25a on the circumference inside the circumference where the permanent magnet 25a is disposed. ) Are preferably arranged. In addition, a plurality of permanent magnets 33b (for example, N poles) having the same polarity and different polarity from the permanent magnets 25b are arranged on the rotor 31 so as to correspond to the permanent magnets 25b provided on the impeller. It is preferable to arrange on a circumference having substantially the same diameter as the circumference of the circle. The plurality of permanent magnets 25 b are preferably arranged so as to be equiangular with respect to the central axis of the impeller 21. The plurality of permanent magnets 33b are preferably arranged so as to be equiangular with respect to the central axis of the rotor 31. The arrangement angle of the plurality of permanent magnets 25b and the arrangement angle of the plurality of permanent magnets 33b are preferably the same or the other arrangement angle is an integral multiple of one arrangement angle.

As shown in FIGS. 3 and 4, the impeller auxiliary suction unit 4 includes at least one electromagnet 41 fixed to suck the magnetic body 28 of the impeller. Specifically, it has a plurality of electromagnets 41 housed in the housing 20. The plurality of electromagnets 41 are provided at equiangular intervals. The electromagnet 41 includes an iron core and a coil. In this embodiment, six electromagnets 41 are provided. The number of electromagnets 41 is preferably 1-8.
In the centrifugal blood pump device 1 of this embodiment, as shown in FIG. 6, the housing 20 includes a housing inner surface that houses the impeller 21 and forms a blood chamber 24, and is disposed on the housing inner surface 20 a on the rotor 31 side. A dynamic pressure groove 38 is provided. The impeller 21 rotates in a non-contact state due to a dynamic pressure bearing effect formed between the dynamic pressure groove 38 and the impeller 21 generated by rotating at a predetermined number of rotations or more.

As shown in FIG. 6, the dynamic pressure groove 38 is formed in a size corresponding to the bottom surface (rotor side surface) of the impeller 21. In the pump device 1 of this embodiment, one end is provided on the peripheral edge (circumference) of the circular portion slightly spaced from the center of the housing inner surface 20a, and it is spiral (in other words, curved) to the vicinity of the outer edge of the housing inner surface 20a. , Extending so that the width gradually widens. Further, a plurality of dynamic pressure grooves 38 are provided, and each of the dynamic pressure grooves 38 has substantially the same shape and is arranged at substantially the same interval. The dynamic pressure groove 38 is a recess, and the depth is preferably about 0.005 to 0.4 mm. About 6 to 36 dynamic pressure grooves are preferably provided. In this embodiment, twelve dynamic pressure grooves are arranged at an equal angle with respect to the central axis of the impeller.
The dynamic pressure groove may be provided not on the housing side but on the rotor side surface of the impeller 21. Also in this case, it is preferable to have the same configuration as the above-described dynamic pressure groove.

Since it has such a dynamic pressure groove, it is attracted to the impeller rotational torque generating portion 3 side, but is formed between the dynamic pressure groove 38 of the housing and the bottom surface of the impeller 21 (or between the dynamic pressure groove of the impeller and the inner surface of the housing). Due to the effect of the hydrodynamic bearing, it is slightly separated from the inner surface of the housing and rotates in a non-contact state to secure a blood flow path between the lower surface of the impeller and the inner surface of the housing. Prevent the occurrence of thrombus. Furthermore, in the normal state, the dynamic pressure groove exhibits a stirring action between the lower surface of the impeller and the inner surface of the housing, thereby preventing partial blood retention between the two.
Furthermore, as shown in FIG. 7, the dynamic pressure groove 38 is preferably chamfered so that a corner portion 38a has an R of at least 0.05 mm. By doing so, the generation of hemolysis can be reduced.

Further, like the centrifugal blood pump device 70 of the example shown in FIGS. 17 and 18, the housing 20 has an inner surface of the housing that houses the impeller 21 and forms the blood chamber 24 in the same manner as that shown in FIG. And a dynamic pressure groove 38 provided on the housing inner surface 20a on the rotor 31 side, and a second dynamic pressure groove 71 provided on the housing inner surface 20b on the electromagnet 41 side. For this reason, the impeller 21 rotates in a non-contact state due to a dynamic pressure bearing effect formed between the dynamic pressure groove 38 and the impeller 21 generated by rotating at a predetermined number of revolutions or more, and receives an external impact. When it is received or when the dynamic pressure by the dynamic pressure groove 38 becomes excessive, the impeller is prevented from sticking to the housing inner surface 20b side.
As shown in FIG. 18, the dynamic pressure groove 71 is formed in a size corresponding to the upper surface (side surface of the electromagnet) of the impeller 21, as with the dynamic pressure groove 38 described above. In the pump device 70 of this embodiment, one end is provided on the peripheral edge (circumference) of the circular portion slightly spaced from the center of the housing inner surface 20b, and in a spiral shape (in other words, curved) to the vicinity of the outer edge of the housing inner surface 20b. , Extending so that the width gradually widens. In addition, a plurality of dynamic pressure grooves 71 are provided, and each of the dynamic pressure grooves 71 has substantially the same shape and is disposed at substantially the same interval. The dynamic pressure groove 71 is a recess, and the depth is preferably about 0.005 to 0.4 mm. About 6 to 36 dynamic pressure grooves are preferably provided. In this embodiment, twelve dynamic pressure grooves are arranged at an equal angle with respect to the central axis of the impeller.

The second dynamic pressure groove may be provided not on the housing side but on the surface of the impeller 21 on the electromagnet side. Also in this case, it is preferable to have the same configuration as the second dynamic pressure groove described above. Further, the dynamic pressure groove 71 is preferably chamfered so that the corner portion thereof has an R of at least 0.05 mm, as in the case shown in FIG. By doing so, the generation of hemolysis can be reduced.
Note that the second dynamic pressure groove is more preferably formed on the housing side. By doing in this way, formation of a dynamic pressure groove is easy. Furthermore, the impeller can be made thinner and lighter in weight than the case where the dynamic pressure groove is formed in the impeller, and such a thin and light impeller has high disturbance resistance.

Next, a centrifugal blood pump device according to another embodiment of the present invention will be described.
FIG. 9 is a block diagram of an embodiment including a control mechanism of the centrifugal blood pump apparatus of the present invention. FIG. 10 is a front view of an example of a centrifugal blood pump device used in the centrifugal blood pump device of the present invention. FIG. 11 is a longitudinal sectional view of the centrifugal blood pump apparatus of the embodiment shown in FIG. 12 is a cross-sectional view of the centrifugal blood pump device of FIG. 10 taken along line BB. 13 is a bottom view of the centrifugal blood pump apparatus of FIG. The plan view of the centrifugal blood pump device of the embodiment shown in FIG. 10 is the same as that of FIG. 3, and is a cross section of the centrifugal blood pump device of FIG. Are the same as those in FIG.
The centrifugal blood pump device 50 of this embodiment includes a housing 20 having a liquid inflow port 22 and a liquid outflow port 23, and a first magnetic body 25 therein. The centrifugal blood pump device 50 rotates in the housing 20 and is centrifuged at the time of rotation. A centrifugal pump unit 2 having an impeller 21 for feeding liquid by force, and a plurality of pumps arranged on the circumference for sucking the first magnetic body 25 of the impeller 21 of the centrifugal pump unit 2 and rotating the impeller 21 An impeller rotational torque generator 3 including the stator coil 61 and a dynamic pressure groove 38 provided on the inner surface of the housing 21 on the stator coil 61 side or on the surface of the impeller 21 on the stator coil 61 side. This is a centrifugal blood pump device in which the impeller 21 is rotated in a non-contact state by the pressure groove 38. The centrifugal blood pump device 50 sucks the first magnetic body 25 of the impeller 21 or the second magnetic body 28 provided separately from the first magnetic body 25 in a direction opposite to the suction direction by the stator coil 61. An electromagnet 41 for assisting the levitation of 21 is provided.

As shown in FIG. 11, the centrifugal blood pump device 50 of this embodiment has a housing 20 having a blood inflow port 22 and a blood outflow port 23, and rotates in the housing 20 to send blood by centrifugal force at the time of rotation. A centrifugal blood pump unit 2 having a liquid impeller 21, an impeller rotational torque generating unit 3 for the impeller 21, and an auxiliary suction control unit 4 for the impeller 21 are provided.
The substantial difference between the pump device 50 of this embodiment and the pump device 1 of the above-described embodiment is only the mechanism of the impeller rotational torque generating unit 3. The impeller rotational torque generator 3 in the pump device 50 of this embodiment is of a type that directly drives the impeller without providing a so-called rotor.
The impeller 21 rotates without contacting the inner surface of the housing due to the pressure generated by the dynamic pressure groove during rotation. In particular, in the pump device 50, the impeller is attracted in the direction opposite to the stator coil by the electromagnet, and thus rotates in a state further separated from the distance between the impeller and the housing obtained by a normal dynamic pressure groove.

The housing 20 includes a blood inflow port 22 and a blood outflow port 23, and is formed of a nonmagnetic material. A blood chamber 24 communicating with the blood inflow port 22 and the blood outflow port 23 is formed in the housing 20. An impeller 21 is accommodated in the housing 20. The blood inflow port 22 is provided so as to protrude substantially vertically from the vicinity of the center of the upper surface of the housing 20. As shown in FIGS. 3 and 12, the blood outflow port 23 is provided so as to protrude in a tangential direction from the side surface of the housing 20 formed in a substantially cylindrical shape.
As shown in FIG. 11, a disc-shaped impeller 21 having a through hole at the center is housed in a blood chamber 24 formed in the housing 20. As shown in FIG. 11, the impeller 21 is formed between a donut plate-like member (lower shroud) 27 that forms a lower surface, and a donut plate-like member (upper shroud) 28 that opens at the center that forms an upper surface. A plurality of (for example, seven) vanes 18. A plurality (seven) blood passages 26 partitioned by the adjacent vanes 18 are formed between the lower shroud and the upper shroud. As shown in FIG. 12, the blood passage 26 communicates with the central opening of the impeller 21 and extends from the central opening of the impeller 21 to the outer peripheral edge so that the width gradually increases. In other words, the vane 18 is formed between the adjacent blood passages 26. In this embodiment, each blood passage 26 and each vane 18 are provided at equal angular intervals and in substantially the same shape.

And as shown in FIG. 12, the impeller 21 has a plurality of (for example, 6 to 12) first magnetic bodies 25 (permanent magnets, driven magnets) embedded therein. In this embodiment, the first magnetic body 25 is embedded in the lower shroud 27. The embedded magnetic body 25 (permanent magnet) attracts the impeller 21 to the side opposite to the blood inflow port 22 by a stator coil 61 of the impeller rotational torque generating unit 3 to be described later, and couples with the operation of the stator coil 61 and rotates. It is provided to transmit torque.
Further, by embedding a certain number of magnetic bodies 25 as in this embodiment, it is possible to sufficiently secure magnetic coupling with a stator coil 61 described later. The shape of the magnetic body 25 (permanent magnet) is preferably substantially trapezoidal. The magnetic body 25 may be either a ring shape or a plate shape. Moreover, it is preferable that the number and arrangement | positioning form of the magnetic body 25 respond | correspond to the number and arrangement | positioning form of a stator coil. The plurality of magnetic bodies 25 are arranged on the circumference so that the magnetic poles are alternately different and at substantially the same angle with respect to the central axis of the impeller.

Further, the impeller 21 includes a second magnetic body 28 provided in the upper shroud itself or in the upper shroud. In this embodiment, the entire upper shroud is formed of the magnetic body 28. The magnetic body 28 is provided to attract the impeller 21 to the side opposite to the stator coil 61, in other words, to the blood inflow port 22 side by the electromagnet 41 of the impeller auxiliary suction portion. As the magnetic body 28, magnetic stainless steel or the like is used.
Since the impeller 21 is attracted to the stator coil side and attracts the impeller in the opposite direction to the stator coil by the electromagnet, the housing is in a non-contact state further separated than the distance between the impeller and the housing obtained by a normal dynamic pressure groove. 20 is rotated.

As shown in FIGS. 11 and 13, the impeller rotational torque generating unit 3 includes a plurality of stator coils 61 housed in the housing 20. A plurality of stator coils 61 are arranged on the circumference so as to be substantially equiangular with respect to the central axis of the circumference. Specifically, six stator coils are used. As the stator coil, a multi-layer stator coil is used. By switching the direction of the current flowing through each stator coil 61, a rotating magnetic field is generated, and the impeller is attracted and rotated by this rotating magnetic field.
The impeller auxiliary suction unit 4 is the same as the centrifugal blood pump device 1 of the above-described embodiment, and therefore the above description is referred to.

  Also in the centrifugal blood pump device 50 of this embodiment, as shown in FIG. 6, the housing 20 includes an inner surface of the housing that houses the impeller 21 and forms the blood chamber 24, and the inner surface of the housing on the stator coil 61 side. A dynamic pressure groove 38 is provided in 20a. The impeller 21 rotates in a non-contact state due to a dynamic pressure bearing effect formed between the dynamic pressure groove 38 and the impeller 21 generated by rotating at a predetermined number of rotations or more. Since the dynamic pressure groove 38 is the same as the centrifugal blood pump device 1 of the above-described embodiment, the above description is referred to. Further, the dynamic pressure groove may be provided not on the housing side but on the surface of the impeller 21 on the stator coil side. Also in this case, it is preferable to have the same configuration as the above-described dynamic pressure groove. Furthermore, as shown in FIG. 7, the dynamic pressure groove 38 is preferably chamfered so that a corner portion 38a has an R of at least 0.05 mm. By doing so, the generation of hemolysis can be reduced.

  Further, also in the centrifugal blood pump device 50 of this type, the housing 20 is provided on the housing inner surface 20b on the electromagnet 41 side as in the centrifugal blood pump device 70 of the example shown in FIGS. A second dynamic pressure groove may be provided. Since the second dynamic pressure groove is the same as the centrifugal blood pump device 70 of the above-described embodiment, the above description should be referred to. Further, the second dynamic pressure groove may be provided not on the housing side but on the surface of the impeller 21 on the electromagnet side. Also in this case, it is preferable to have the same configuration as the above-described dynamic pressure groove. Furthermore, it is preferable that the second dynamic pressure groove is chamfered so that the corner portion has an R of at least 0.05 mm, as in the case shown in FIG. By doing so, the generation of hemolysis can be reduced.

Moreover, it is preferable to provide the control mechanism 6 in the centrifugal blood pump device of the above-described embodiment.
A control mechanism 6 used in the centrifugal blood pump device 1 will be described with reference to FIGS. 1 and 9.
The control mechanism 6 of the centrifugal blood pump apparatus 1 of the embodiment shown in FIG. 1 is for the power amplifier 52 for the motor 34 of the impeller rotational torque generating unit 3, the motor control circuit 53, the motor current monitoring unit 55, and the electromagnet 41. Power amplifier 54, electromagnet control circuit 56, electromagnet current monitoring unit 57, and control unit 51. The motor current monitoring function may be provided in the control unit 51.
The control mechanism 6 of the centrifugal blood pump device 50 of the embodiment shown in FIG. 9 includes a power amplifier 62 for the stator coil 61 of the impeller rotational torque generating unit 3, a stator coil control circuit 63, a stator coil current monitoring unit 64, an electromagnet. 41, an electromagnet control circuit 56, an electromagnet current monitoring unit 57, and a control unit 51. The stator coil current monitoring function may be included in the control unit 51.

Then, the control mechanism 6 controls the impeller rotational torque generating unit (specifically, a motor or a stator coil) and the electromagnet 41. In particular, the control mechanism 6 has a function of changing the attraction force of the impeller by the electromagnet 41 in accordance with the rotation speed of the impeller rotation torque generation unit (in other words, the rotation speed generated by the impeller rotation torque generation unit). Is preferred. Further, the control mechanism 6 changes the attraction force of the impeller 21 by the electromagnet 41 according to the rotation speed of the impeller rotation torque generation unit (in other words, the rotation speed generated by the impeller rotation torque generation unit). It is preferable to have a function of keeping the distance between the housings substantially constant, and this distance is preferably 50 to 150 μm. Specifically, the centrifugal blood pump devices 1 and 50 have an impeller rotation torque generation unit current monitoring function, and the control mechanism 6 uses the motor current value detected by the impeller rotation torque generation unit current monitoring function. The electromagnet is controlled.
The reason why the attraction force of the impeller by the electromagnet is changed in accordance with the rotational speed of the impeller rotational torque generating unit (specifically, the motor or the stator coil) is that load capacity is generated by the dynamic pressure groove. Load capacity is a term for bearings and has a dimension of force. Acts in the same direction as the attractive force of the electromagnet. In the case of a stepped groove with a simple dynamic pressure groove shape, this load capacity is calculated based on a two-dimensional theoretical analysis (considering only the cross-sectional shape of the dynamic pressure groove, the length direction perpendicular to the cross section is According to the analysis performed as long as possible, it is proportional to the viscosity and the rotational speed of the fluid.

In the centrifugal blood pump devices 1 and 50 according to the above-described embodiments, 1) a coupling force (permanent magnet in the pump device 1 and stator coil in the pump device 50) acts between the impeller and the motor, and 2) the impeller Between the electromagnets, an attractive force by the electromagnets and a load capacity by the dynamic pressure grooves work.
At a position where the force 1) and the force 2) are balanced, the impeller floats and rotates in the housing. The distance between the impeller and the housing is preferably a sufficiently small distance that does not cause hemolysis, but in order to increase the distance, the electromagnet current must be increased. Therefore, it is desirable from the viewpoint of power consumption that the distance between the impeller and the housing is larger than the distance obtained by only the dynamic pressure groove and has an allowable small value. Therefore, it is necessary to control so that the distance between the impeller and the housing is balanced at a small allowable value. That is, when the force of 1) is constant, the force of 2) needs to be constant even if the rotational speed changes. The force of 2) is the sum of the attractive force of the electromagnet and the load capacity. If the load capacity changes depending on the number of rotations, the target floating position can be determined by making the sum constant by changing the attractive force of the electromagnet. Can be secured. Specifically, since the load capacity at the force of 2) increases with the impeller rotation speed, the target floating position can be secured even if the attraction force of the electromagnet (in other words, the electromagnet current) is reduced. The power consumption is low.

Next, the two-dimensional theoretical analysis result in the case where the above-described dynamic pressure groove has a simple stepped groove will be described.
Considering the case of the dynamic pressure groove having the shape of FIG. 15 (the length in the cross-sectional direction of the groove is L), the pressure p is
For region 1 (0 <x <Bo): p = (Pm / Bo) x
For region 2 (Bo <x <B): p = [Pm / (B−Bo)] (B−x)
(The change in the y direction of p is sufficiently small and can be ignored). here,
Pm = 6 μU (h ₁ −h ₂ ) / [h ₁ ³ / Bo + h ₂ ³ / (B−Bo)]
It is. In the equation, μ and U are respectively the viscosity of the fluid and the radial speed of the impeller (proportional to the number of rotations).
Therefore, the load capacity W is
W = L∫ ₀ ^B pdx
= LBPm / 2
It is. Wd-less, which is made dimensionless by dividing this W by μULB ² ,
Wd-less = Wh ₂ ² / (μULB ² )
= 3s (1-s) ( a-1) / [a 3 (1-s) + s]
It is. Where a and s are
a = h ₁ / h ₂ s = Bo / B
It is. Then, the change of Wd-less with respect to a and s is as shown in FIG. 16, and the maximum load capacity can be obtained (highly efficient) s (Bo and B) when desired h ₁ and h ₂ are set. Ratio) exists. Therefore, the shape parameter of the dynamic pressure groove:
h ₁ -h ₂
B, Bo, L
By setting to an appropriate value, a sufficient load capacity can be obtained, and as a result, a power-saving blood pump that suppresses the attractive force of the electromagnet can be provided.

  The control mechanism 6 preferably includes a rotation start state control function for starting rotation by the impeller rotation torque generation unit in a state where the impeller 21 is attracted by the electromagnet 41 with a force equal to or greater than a predetermined value. Further, the control mechanism 6 includes a rotation start state control function for starting rotation by the impeller rotation torque generation unit 3 in a state where the impeller 21 is attracted by the electromagnet 41 with a suction force of a predetermined value or more, and the impeller rotation torque generation unit 3. It is preferable to provide a post-rotation control function for the impeller rotation torque generating unit that lowers the suction force from the predetermined value after the rotation of the rotation is started. It is preferable that the post-rotation control function of the impeller rotational torque generator changes the impeller attractive force by the electromagnet according to the rotational speed of the impeller rotational torque generator 3.

Furthermore, it is preferable that the control mechanism 6 has a function of detecting a so-called step-out state in which the coupling between the impeller 21 and the impeller rotational torque generating unit 3 is disconnected. Furthermore, it is preferable to provide a recoupling function that operates after step-out detection.
Specifically, the control unit 51 includes a step-out detection function that determines that the step-out state is detected using the output from the motor current monitoring unit 55 and a recoupling function that operates after detection of the step-out. . As the recoupling function, for example, after the step-out is detected, the motor and the electromagnet 41 are temporarily stopped, then only the electromagnet 41 is operated, and then the rotation by the impeller rotational torque generator is started. preferable. The step-out determination may be determined as step-out when the control unit stores the lowest impeller rotational torque generating unit current value and is lower than the value. Further, the determination of the step-out may be made by determining that the impeller rotational torque generating unit current is smaller than a predetermined value with respect to the rotation speed by the impeller rotational torque generating unit 3. Specifically, the motor current value (for example, 0.12 A) at a predetermined motor rotation number (for example, 1000 rpm) is stored, and the motor is in spite of the fact that the actual motor rotation state is larger than the above rotation number. When the current is smaller than the motor current value, it is determined that the impeller and the rotor are separated from each other.

Next, the operation of the centrifugal blood pump device 1 of this embodiment will be described with reference to the flowchart shown in FIG.
When the centrifugal blood pump device 1 is started, an electromagnet is first activated to apply an attractive force to the impeller 21 on the side opposite to the impeller rotational torque generator 3 (specifically, a rotor or a stator coil). Then, after the electromagnet current value reaches a predetermined value, rotation by the impeller rotation torque generator 3, specifically, rotation of the motor is started, and the impeller 21 rotates. As an application method of the electromagnet current, there is also a method of adjusting the attractive force by the electromagnet 41 by changing the duty ratio of the rectangular waveform current. Then, the electromagnet current is controlled in accordance with the rotational speed by the impeller rotational torque generator 3. Specifically, the attraction force of the impeller 21 by the electromagnet 41 is reduced by reducing the electromagnet current by the distance from the inner surface of the housing of the impeller 21 due to the increase in load capacity due to the increase in the rotation speed of the impeller 21. In parallel with the electromagnet current control, it is always detected whether or not the motor current is within the predetermined range. If the motor current is outside the predetermined value range, it is determined that the motor has stepped out, and the motor 34 and the electromagnet 41 are temporarily stopped. And only an electromagnet is operated and it transfers to a normal operation | movement.

FIG. 1 is a block diagram of an embodiment including a control mechanism of a centrifugal blood pump apparatus of the present invention. FIG. 2 is a front view of an example of a centrifugal blood pump device used in the centrifugal blood pump device of the present invention. FIG. 3 is a plan view of the centrifugal blood pump apparatus shown in FIG. FIG. 4 is a longitudinal sectional view of the centrifugal blood pump apparatus of the embodiment shown in FIG. 5 is a cross-sectional view of the centrifugal blood pump device of FIG. 2 taken along line AA. 6 is a cross-sectional view showing a state where the impeller is removed from the cross-sectional view taken along the line AA of the centrifugal blood pump device of FIG. FIG. 7 is an explanatory view for explaining the shape of the corner of the dynamic pressure groove of the centrifugal blood pump device of the present invention. FIG. 8 is an explanatory diagram for explaining a magnetic coupling configuration between an impeller and a rotor used in the centrifugal blood pump device of the present invention. FIG. 9 is a block diagram of an embodiment including a control mechanism of the centrifugal blood pump apparatus of the present invention. FIG. 10 is a front view of an example of a centrifugal blood pump device used in the centrifugal blood pump device of the present invention. FIG. 11 is a longitudinal sectional view of the centrifugal blood pump apparatus of the embodiment shown in FIG. 12 is a cross-sectional view of the centrifugal blood pump device of FIG. 10 taken along line BB. 13 is a bottom view of the centrifugal blood pump apparatus of FIG. FIG. 14 is a flowchart for explaining the operation of the centrifugal blood pump apparatus according to one embodiment of the present invention. FIG. 15 is an explanatory diagram for explaining a two-dimensional theoretical analysis process regarding the dynamic pressure groove. FIG. 16 is an explanatory diagram for explaining a two-dimensional theoretical analysis result regarding the dynamic pressure grooves. FIG. 17 is a cross-sectional view of another example of the centrifugal blood pump device used in the centrifugal blood pump device of the present invention. 18 is a cross-sectional view showing a state where the impeller is removed from the cross-sectional view taken along the line CC of the centrifugal blood pump device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Centrifugal blood pump apparatus 2 Centrifugal pump part 3 Impeller rotational torque generating part 20 Housing 21 Impeller 25 First magnetic body 31 Rotor 33 Magnet 34 Motor 38 Dynamic pressure groove 41 Electromagnet

Claims (8)

A housing having a liquid inflow port and a liquid outflow port; a centrifugal pump unit having an impeller that includes a first magnetic body therein, rotates in the housing, and sends liquid by centrifugal force during rotation; A rotor including a magnet for attracting the first magnetic body of the impeller of the centrifugal pump unit; an impeller rotational torque generating unit including a motor for rotating the rotor; and an inner surface of the housing on the rotor side or the rotor of the impeller A centrifugal blood pump device comprising a dynamic pressure groove provided on a side surface, wherein the impeller rotates in a non-contact state by the dynamic pressure groove with respect to the housing,
The centrifugal blood pump device does not have a position sensor for the impeller, and the first magnetic body of the impeller or a second magnetic body provided separately from the first magnetic body And a control mechanism for controlling the impeller rotation torque generator and the electromagnet, the control mechanism comprising: an impeller that attracts the rotor in a direction opposite to the suction direction by the magnet of the rotor ; A rotational torque generator current monitoring function is provided, and the electromagnet is controlled using a current value detected by the monitoring function. Further, the control mechanism causes the impeller to force the impeller to a force greater than a predetermined value. A rotation start state control function for starting rotation by the impeller rotational torque generating unit in a state where the impeller is rotated and the impeller rotational torque generating unit Rotating after the start by centrifugal blood pump apparatus, characterized in that the suction force is intended and a impeller rotation torque generating section rotating after the control function to lower than the predetermined value. Both the first magnetic body included in the impeller and the magnet included in the rotor for attracting the first magnetic body are a plurality of permanent magnets, and the plurality of permanent magnets have the same polarity on substantially the same circumference. The permanent magnet included in the impeller and the permanent magnet included in the rotor are disposed on a circumference facing each other and have opposite polarities. The centrifugal blood pump device described in 1. A housing having a liquid inflow port and a liquid outflow port; a centrifugal pump unit having an impeller that includes a first magnetic body therein, rotates in the housing, and sends liquid by centrifugal force during rotation; An impeller rotational torque generator including a plurality of stator coils arranged on the circumference for attracting the first magnetic body of the impeller of the centrifugal pump unit and rotating the impeller; and an inner surface of the housing on the stator coil side Or a centrifugal blood pump device comprising a dynamic pressure groove provided on the surface of the impeller on the side of the stator coil, wherein the impeller rotates in a non-contact state by the dynamic pressure groove with respect to the housing,
The centrifugal blood pump device does not have a position sensor for the impeller, and the first magnetic body of the impeller or a second magnetic body provided separately from the first magnetic body And a control mechanism for controlling the impeller rotation torque generator and the electromagnet, and the control mechanism is configured to rotate the impeller. A torque generator current monitoring function is provided, and the electromagnet is controlled using a current value detected by the monitoring function. Further, the control mechanism is configured to control the impeller with a force of a predetermined value or more by the electromagnet. A rotation start state control function for starting rotation by the impeller rotation torque generation unit in the sucked state, and the impeller rotation torque generation After the start of rotation by the parts, centrifugal blood pump apparatus characterized in that comprises an impeller rotational torque generating section rotating after the control function of the suction force is lower than the predetermined value. The centrifugal blood pump device includes a control mechanism for controlling the impeller rotational torque generating unit and the electromagnet, and the control mechanism is configured to control the impeller driven by the electromagnet according to the rotational speed of the impeller rotational torque generating unit. The centrifugal blood pump device according to any one of claims 1 to 3, which has a function of changing suction force. The control mechanism has a function of maintaining a substantially constant distance between the impeller and the housing by changing an attraction force of the impeller by the electromagnet according to the rotational speed of the impeller rotational torque generating unit. The centrifugal blood pump device according to claim 4. The centrifugal blood pump device according to any one of claims 1 to 5 , wherein the dynamic pressure groove is chamfered such that a corner portion of the dynamic pressure groove has an R of at least 0.05 mm or more. The centrifugal blood pump device according to any one of claims 1 to 6 , further comprising a second dynamic pressure groove provided on a housing inner surface of the electromagnet side or a surface of the impeller on the electromagnet side. Blood pump device. The centrifugal blood pump device according to claim 7 , wherein the second dynamic pressure groove is chamfered so that a corner portion of the dynamic pressure groove has an R of at least 0.05 mm or more.

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