JP4694023B2 - Centrifugal liquid pump device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a centrifugal liquid pump apparatus for transporting medical fluid such as blood.
[0002]
[Prior art]
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. Such a centrifugal blood pump has a housing having a blood inflow port and a blood outflow port, and an impeller that rotates in the housing and feeds blood by centrifugal force during rotation. Further, the impeller is rotated by a rotational torque generating mechanism that includes a permanent magnet inside and a rotor that includes a magnet for attracting the magnet of the impeller and a motor that rotates the rotor. The impeller is also attracted by the magnetic force on the side opposite to the rotor, and rotates in a non-contact state with respect to the housing. This state is called a magnetic levitation state.
[0003]
[Problems to be solved by the invention]
In the centrifugal liquid pump using such a magnetic coupling, a reduction in rigidity during use becomes a problem. The decrease in rigidity is a decrease in the force required for the movement of the impeller per unit length during magnetic levitation. In other words, the impeller moves with less force in the reduced rigidity state. For this reason, the impeller is easily affected by external vibration, impact, and the like, and the possibility of causing the step-out becomes relatively high.
As a result of studies by the present inventors, such a decrease in rigidity occurs, for example, in a predetermined rotation speed region of the centrifugal liquid pump, or receives a shock from the outside, and the impeller is perpendicular to the rotation axis. It has been found that it occurs relatively frequently when moving. In both the direction of the rotation axis and the direction orthogonal thereto, the rigidity can be improved by bringing the impeller closer to the motor side, but this leads to an increase in power consumption. When the impeller is moved closer to the motor side, the force of the permanent magnet on the motor side attracts the impeller is increased. To counter this, the electromagnet also increases the attraction force, so that the electromagnet current increases and the power consumption increases.
[0004]
Accordingly, an object of the present invention is to provide a centrifugal liquid pump that normally operates in a low power consumption state and has a function of automatically correcting the rigidity of the centrifugal liquid pump so that the rigidity is improved when the rigidity of the centrifugal liquid pump is reduced. is there.
In JP-A-11-76394, the applicant of the present application includes a centrifugal liquid pump device main body portion and a controller, and the pump device main body portion includes a housing and a pump portion having an impeller rotating within the housing; An impeller rotational torque generation unit including a motor for rotating the impeller, and an impeller position control unit, the impeller is a centrifugal liquid pump device that rotates in a non-contact state with respect to the housing, and the controller includes the impeller Using the position control unit, the impeller flying position control function that changes the flying position of the impeller in the housing, the current measurement function of the motor, and the current change amount of the motor obtained by changing the flying position of the impeller Has proposed a centrifugal pump device with a liquid viscosity calculation function to calculate the viscosity of the liquid
Even in the above publication, the floating position of the impeller is changed, but this is for the calculation of the liquid viscosity. This publication always operates in a low power consumption state, and the rigidity of the centrifugal liquid pump It does not provide a centrifugal liquid pump having a function of automatically correcting to improve rigidity when it is lowered.
[0005]
[Means for Solving the Problems]
To achieve the above purpose,
(1) A housing having a liquid inflow port and a liquid outflow port, and a first magnetic body and a second magnetic body are provided therein, rotate inside the housing, and send liquid by centrifugal force during rotation. A centrifugal liquid pump unit having an impeller, a rotor including a magnet for attracting the first magnetic body of the impeller of the centrifugal liquid pump unit, and an impeller rotational torque generating unit including a motor for rotating the rotor; An impeller position control unit having an electromagnet for attracting the second magnetic body of the impeller, and a position sensor for detecting the position of the impeller, wherein the impeller is in a non-contact state with respect to the housing A centrifugal liquid pump device comprising a rotating centrifugal liquid pump device main body and a control device for the centrifugal liquid pump device main body, the control device Has a motor rotation speed monitoring function and a storage function for storing the impeller low-rigidity rotation speed area, and the motor rotation speed detected by the rotation speed monitoring function is within the impeller low-rigidity rotation speed area stored by the storage function. Then, the impeller floating position is moved to the rotor side, and the motor rotation speed detected by the rotation speed monitoring function is out of the impeller low-rigidity rotation speed area stored by the storage function. Sometimes, the centrifugal liquid pump device has an impeller flying position control function for returning the flying position of the impeller to a position before the change.
(2) In the above (1), the control device includes an impeller low-rigidity state detection function for detecting an impeller low-rigidity state using an output of the position sensor. A function of moving the impeller floating position to the rotor side when the impeller low rigidity state is detected by the rigidity state detecting function and returning the impeller floating position to the position before the change after a predetermined time has elapsed. It is preferable to provide.
[0006]
In addition, those that achieve the above objectives
(3) A housing having a liquid inflow port and a liquid outflow port, and a first magnetic body and a second magnetic body are provided therein, rotate inside the housing, and send liquid by centrifugal force during rotation. A centrifugal liquid pump unit having an impeller, a rotor including a magnet for attracting the first magnetic body of the impeller of the centrifugal liquid pump unit, and an impeller rotational torque generating unit including a motor for rotating the rotor; An impeller position control unit having an electromagnet for attracting the second magnetic body of the impeller, and a position sensor for detecting the position of the impeller, wherein the impeller is in a non-contact state with respect to the housing A centrifugal liquid pump device comprising a rotating centrifugal liquid pump device main body and a control device for the centrifugal liquid pump device main body, the control device Impeller low-rigidity state detection function that detects the impeller low-rigidity state using the output of the position sensor, and when the impeller low-rigidity state is detected by the impeller low-rigidity state detection function, the impeller floating position This is a centrifugal liquid pump device having an impeller flying position control function for moving the rotor to the rotor side and returning the floating position of the impeller to the position before the change after a predetermined time has elapsed.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The centrifugal liquid pump device of the present invention will be described with reference to an embodiment in which it is applied to a blood pump.
FIG. 1 is a block diagram of an embodiment of a centrifugal liquid pump apparatus according to the present invention. FIG. 2 is a front view of an example of a centrifugal liquid pump device main body used in the centrifugal liquid pump device of the present invention. FIG. 3 is a plan view of the centrifugal liquid pump device main body shown in FIG. 4 is a longitudinal sectional view of the centrifugal liquid pump device main body of the embodiment shown in FIG. FIG. 5 is a cross-sectional view taken along line AA of the centrifugal liquid pump device main body of FIG.
The centrifugal liquid pump device 1 of the present invention includes a housing 20 having a liquid inflow port 22 and a liquid outflow port 23, a first magnetic body 25 and a second magnetic body 28 inside, and rotates within the housing 20. A rotor including a centrifugal liquid pump unit 2 having an impeller 21 for feeding a liquid by centrifugal force during rotation, and a magnet 33 for attracting the first magnetic body 25 of the impeller 21 of the centrifugal liquid pump unit 2 31, an impeller rotational torque generator 3 having a motor 34 for rotating the rotor 31, and an electromagnet 41 for attracting the impeller 21 (specifically, a second magnetic body 28 provided on the impeller 21 is attracted). An impeller position control unit 4 including an electromagnet 41 for detecting the position, and a position sensor 42 (specifically, a second magnetic body provided on the impeller 21) for detecting the position of the impeller And a control for the centrifugal liquid pump device main body 5 in which the impeller 21 rotates in a non-contact state with respect to the housing. A centrifugal liquid pump device including the device 6.
[0008]
The control device 6 for the centrifugal liquid pump of this embodiment has a motor rotation speed monitoring function and a storage function for storing the impeller low-rigidity rotation speed area, and the motor rotation speed detected by the rotation speed monitoring function is a storage function. When the impeller is in the low-rigidity rotational speed region stored, the impeller 21 is moved to the rotor side, and the motor rotational speed detected by the rotational speed monitoring function is stored in the storage function. An impeller flying position control function is provided for returning the flying position of the impeller 21 to the position before the change when the rotation speed is outside the rotation speed range.
Furthermore, the control device 6 of the centrifugal liquid pump detects the impeller low rigidity state by the impeller low rigidity state detection function that detects the impeller low rigidity state by using the position sensor output, and the impeller low rigidity state detection function. Furthermore, it is preferable to provide an impeller flying position control function for moving the flying position of the impeller 21 to the rotor side and returning the flying position of the impeller to the position before the change after a predetermined time has elapsed.
The control device 6 for the centrifugal liquid pump according to the present invention does not have the above-described rotational speed monitoring function, impeller low-rigid rotational speed area storage function, and impeller flying position control function using them, and outputs the position sensor 42. The impeller low rigidity state detection function for detecting the impeller low rigidity state using the impeller, and when the impeller low rigidity state is detected by the impeller low rigidity state detection function, the impeller floating position is moved to the rotor side, and In addition, an impeller flying position control function may be provided to return the impeller flying position to the position before the change after a predetermined time has elapsed.
[0009]
As shown in FIGS. 2 to 5, the centrifugal liquid pump device main body 5 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 centrifugation during rotation. Centrifugal liquid pump unit 2 having an impeller 21 for feeding blood by force, an impeller rotational torque generating unit (non-controllable magnetic bearing component) 3 for the impeller 21, and an impeller position control unit for the impeller 21 (Control type magnetic bearing component) 4.
As shown in FIG. 4, the impeller 21 is held at a predetermined position in the housing 20 by the action of the non-control type magnetic bearing component 3 and the control type magnetic bearing component 4 and normally does not contact the inner surface of the housing. Rotate.
[0010]
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.
[0011]
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.
[0012]
As shown in FIG. 4, a plurality (for example, 24 pieces) of first magnetic bodies 25 (permanent magnets, driven magnets) are embedded in the impeller 21. 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 to be described later, and the rotational torque is rotated by the impeller. It is provided for transmission from the torque generator.
[0013]
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 with alternating magnetic poles.
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 for attracting the impeller 21 to the blood inflow port 22 side by an electromagnet 41 of an impeller position control unit described later. As the magnetic body 28, magnetic stainless steel or the like is used.
[0014]
The impeller position control unit 4 and the impeller rotational torque generating unit 3 constitute a non-contact magnetic bearing, and the impeller 21 is pulled in an opposite direction so that the appropriate position in the housing 20 that does not contact the inner surface of the housing 20 is obtained. The housing 20 rotates in a non-contact state.
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 liquid 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.
The impeller rotational torque generating unit 3 is not limited to the one provided with the above-described rotor and motor, and may be composed of, for example, a plurality of stator coils for attracting and rotating the permanent magnet 25 of the impeller 21.
[0015]
The impeller position control unit 4 includes a plurality of fixed electromagnets 41 for attracting the impeller magnetic body 28 and a position sensor 42 for detecting the position of the impeller magnetic body 28. Specifically, the impeller position control unit 4 includes a plurality of electromagnets 41 housed in the housing 20 and a plurality of position sensors 42. The plural (three) electromagnets 41 and the plural (three) position sensors 42 of the impeller position control unit are provided at equiangular intervals, and the electromagnet 41 and the position sensor 42 are also provided at equiangular intervals. ing. The electromagnet 41 includes an iron core and a coil. In this embodiment, three electromagnets 41 are provided. The number of electromagnets 41 may be three or more, for example, four. Three or more are provided, and these electromagnetic forces are adjusted using the detection result of the position sensor 42 to balance the force in the rotation axis (z-axis) direction of the impeller 21 and to be orthogonal to the rotation axis (z-axis). The moment about the x and y axes can be controlled.
[0016]
The position sensor 42 detects the gap interval between the electromagnet 41 and the magnetic body 28, and this detection output is sent to the control unit 51 of the control device 6 that controls the current or voltage applied to the coil of the electromagnet 41. Even if a radial force due to gravity or the like acts on the impeller 21, the magnetic flux shearing force between the permanent magnet 25 of the impeller 21 and the permanent magnet 33 of the rotor 31 and the force between the electromagnet 41 and the magnetic body 28. Since the shearing force of the magnetic flux acts, the impeller 21 is held at the center of the housing 20.
The centrifugal liquid pump apparatus as shown in FIG. 4 can be replaced with a physical model as shown in FIG. The equations that hold in this system are the following equations (1), (2), and (3).
[0017]
v = dz / dt (1)
m (dv / dt) = f_m-K (i / z)²+ F_d ... (2)
e = L (di / dt) + Ri (3)
However, in the expression (3), the term of speed electromotive force is ignored. In addition, as shown in FIG.
z: displacement in the magnetic bearing control direction, v: velocity in the z direction,
m: mass of impeller, fm: attractive force by permanent magnet,
k: electromagnet attractive force coefficient, i: coil current,
fd: external force such as vibration / impact, e: coil voltage,
L: Coil inductance, R: Coil resistance, t: Time
It is.
[0018]
Next, linearization is performed in consideration of a small change around the equilibrium point. That is,
z = Z + z ′ (4.1)
i = I + i ′ (4.2)
e = E + e ′ (4.3)
far. Here, capital letters Z, I, and E are steady values of displacement, current, and voltage, respectively. The term with a lowercase “′” is each minute change. Substituting these formulas into formulas (2) and (3),
External force f_d= 0 and z '= i' = e '= 0
Then, it can be seen that there is the following relationship between the steady values.
f_m= K (I / Z)² ・ ・ ・ ・ ・ ・ (5.1)
RI = E (5.2)
Substituting equation (4) into equations (2) and (3) and considering equation (5), the following equations (6) and (7) are obtained.
m (dv / dt) = k_mz '+ K_Fi ’+ f_d  (6)
L (di '/ dt) + Ri' = e '(7)
Where k_m= 2kI²/ Z³  .... (8.1)
K_F= -2kI / Z²  ... (8.2)
And both are constants.
[0019]
In the magnetic bearing, the state variables z ′, v, i ′ to be controlled are detected, and the coil voltage e is controlled. Furthermore, if the integrated value of the change in displacement is also taken into the feedback, the target gap can be constantly maintained. This corresponds to PID control which is a general control method. That is,
e ’= K_Pz '+ K_Dv'-K_ii ’+ K_I∫z'dt (9)
It is.
[0020]
Expressions obtained by Laplace transform of Expressions (6), (7), and (9) are as follows (the target value r is introduced). The underlined state variables are Laplace transformed functions. FIG. 7 shows a block diagram of the control system based on the Laplace transformed equation. This figure shows the process from the displacement target value r to the displacement z '.
This figure shows the following.
[1] The loop on the rightmost side is a positive feedback, and this is the reason why the magnetic levitation system is inherently unstable.
[2] In this way, an originally unstable system is stabilized by feedback control, but not only for “stabilization” but also by actively incorporating active control such as PID control to improve system characteristics. It is designed to be freely designed.
[0021]
e '= (r−z ') (K_P+ K_I/ S) -K_i i '+ K_D v  ・ ・ ・ ・ ・ ・ （10.1）
msv=i 'K_F+f _d + K_m z '  .... (10.2)
Lsi '=e '-Ri '.... (10.3)
v= Sz '  .... (10.4)
[0022]
Hereinafter, in the equation (10), the target value r = 0 is set.f _d /z 'Calculate Since this physical quantity is a value indicating how much force is required to move the unit length, it corresponds to the rigidity of the magnetic bearing.
Substituting (10.3) and (10.4) into (10.2),e ',i 'Eachz 'Whenf _d Substituting into equation (10.1) as a function off _d /z 'Is obtained as equation (11).
f _d /z '= MD (s) / [s {s + (R + Ki) / L}] (11.1)
However,
D (s) = s⁴+ (R + K_i) S³/ L + (-k_m-K_FK_D/ L) s²/ M + [K_FK_P-(R + K_i) K_m] S / (mL) + K_FK_I/ (ML) ... (11.2)
It is. When the frequency characteristic of the absolute value of rigidity is approximated from the equation (11),
｜f _d (Jω) /z '(Jω) | = −K_FK_I/ [(R + K_i) Ω]
(Ω << ω_c) (12.1)
｜f _d (Jω) /z '(Jω) | = mω²
(Ω >> ω_c) (12.2)
It becomes. However,
ω_c= [-K_FK_I/ {M (R + K_i]}]^1/3(13)
It is. Where ω_cIs the intersection of (12.1) and (12.2) (ω_c, S_min) Coordinates. This S_minIs shown below.
S_min= [-K_FK_I/ {M^1/2(R + K_i]}]^2/3(14.1)
= [2kIK_IZ^-2m^1/2/ (R + K_i]]^2/3(14.2)
[0023]
The meanings of these equations (12), (13), and (14) are shown in FIG. 8, which is an overview of the rigidity in the z direction. FIG. 9 shows an overview of rigidity in the x and y directions, which are radial directions. In either case, in the region where ω (frequency of external force) is high, it is governed only by the mass [refer to equation (12.2)].
In the z direction in which position control is actively performed, the rigidity does not change significantly due to the movement of the equilibrium point (in other words, the impeller flying position). However, since the passive control is performed and the stiffness is lower than that in the z direction, the stiffness changes greatly when the equilibrium point is moved in the x and y directions. Particularly, a decrease in rigidity at the minimum point shown in FIG. 9 becomes a problem.
[0024]
In order to improve this, it is effective to increase the rigidity by bringing the equilibrium point closer to the permanent magnet side. When the equilibrium point is close to the permanent magnet side,
a) Increase in spring constant due to increase in magnetic coupling force
b) Damping by fluid force is improved because the gap between the impeller and the housing (permanent magnet side) is reduced.
The rigidity becomes higher.
However, bringing the balance point (impeller levitation position) closer to the permanent magnet side (rotor side) leads to an increase in current consumption. Therefore, the balance point is normally operated only when necessary. It is practical to increase the rigidity close to the magnet side.
For this reason, the control apparatus 6 is provided with the following functions.
[0025]
The control device 6 will be described with reference to FIG.
The control device 6 includes a motor driver including a power amplifier 52 and a motor control circuit 53 for the motor 34 for magnetic coupling, a power amplifier 54 for the electromagnet 41, a sensor circuit 55 for the sensor 42, and a PID compensator 56. And a controller 51 for detecting the motor rotation speed using a signal output from the motor control circuit.
The control unit 51 includes a storage function for storing an impeller low-rigidity rotational speed region in a centrifugal liquid pump to be used as a first impeller low-rigidity state detection function.
[0026]
As shown in FIG. 9, a reduction in rigidity occurs in the rotation speed region where the impeller is present. This region differs depending on the size of the pump and the like (in other words, the size of the impeller), but can be obtained by calculation or measurement in advance. The control unit 51 stores the impeller low-rigidity rotational speed region.
The impeller low-rigidity rotational speed region can be obtained by measurement or calculation as follows.
When obtaining by measurement, the x-axis, y-axis, and z-axis are each vibrated to the centrifugal pump by the vibrator at each rotation speed, and the acceleration required to move the impeller per unit length (convertible to force) Is measured to obtain the frequency characteristic of rigidity. The rotation speed range in which the acceleration required for the movement of the impeller per unit length is equal to or less than a set threshold value (for example, the minimum value of the stiffness frequency characteristic is equal to or less than the threshold value) is the low-rigidity rotation region. In the case of calculation, the low-rigidity rotation region can be calculated by modeling a real centrifugal pump and using the above-described equation (11).
[0027]
Then, when the motor rotation number detected by the motor rotation number monitoring function (in other words, the motor rotation number detector 58) falls within the impeller low-rigidity rotation number region stored by the storage function, the control unit 51 A function of moving the floating position of the impeller 21 to the rotor side is provided. Specifically, as shown in the flowchart of FIG. 12, the motor rotation speed is constantly monitored during motor rotation, and when the motor rotation speed falls within the impeller low-rigidity rotation speed region stored by the storage function, The controller 51 activates the impeller flying position control function. Specifically, the impeller flying position is intentionally shifted to the rotor side. Thereby, as shown in FIG. 10, the impeller 21 moves slightly to the rotor side. When the impeller 21 moves to the rotor side, the impeller flying position is returned to the original position, and the magnetic levitation state is stabilized at that position.
[0028]
And when the control part 51 detects the motor rotation speed by a rotation speed monitoring function continuously and detects that the detected motor rotation speed became out of the impeller low-rigidity rotation speed area | region which a memory | storage function memorize | stores, The impeller flying position control function is activated again, and the impeller flying position is restored before being lowered. In other words, the flying position of the impeller 21 is returned to the position before the change by increasing the predetermined value. Specifically, when the motor rotation speed is outside the impeller low-rigidity rotation speed area stored by the storage function, the control unit 51 sends a signal to the sensor circuit 55 to move the impeller 21 to the electromagnet 41 side. Move slightly.
Furthermore, the control unit 51 has a second impeller low-rigidity state detection function that detects the impeller low-rigidity state using the output of the position sensor 42.
[0029]
The magnetic bearing position sensor output indicates the floating position of the impeller in the axial direction, and the control device performs the floating control so that the sensor output becomes zero. When a periodic external force is applied to the impeller, the sensor output value deviates from zero. Therefore, when the sensor output value becomes larger than a certain value, it is determined that the impeller has a low rigidity state. As a case where the sensor output value becomes larger than a certain value, there may be a case where a momentary external force such as impact or rotation is applied, or a case where a periodic excitation force such as vibration is applied.
[0030]
Then, when the impeller low rigidity state is detected by the impeller low rigidity state detection function provided in the control unit 51, in other words, when the sensor output exceeds a predetermined value (threshold), the impeller is determined to be in the low rigidity state. The controller 51 operates the impeller flying position control function to move the flying position of the impeller 21 to the rotor 33 side. And after predetermined time progress, the control part 51 operates an impeller floating position control function, and returns the impeller floating position to the position before a change.
Specifically, as shown in the flowchart of FIG. 12, the control unit constantly monitors the position sensor output during motor rotation, and when the sensor output exceeds a predetermined value (threshold), the impeller is in a low rigidity state. to decide. And the control part 51 moves the impeller 21 to the rotor side a little by sending a signal to the sensor circuit 55 and intentionally shifting the sensor output. Then, the control unit 51 sends a signal to the power amplifier 54 after a predetermined time has elapsed (for example, after 3 to 15 minutes have elapsed) to increase the supply current or voltage to the electromagnet 41 (return to the value before the decrease). ), The impeller 21 is slightly moved to the electromagnet 41 side.
[0031]
The measurement by the position sensor is basically intended to measure displacement in the direction of the rotation axis (axial direction) of the impeller, but is also affected by the displacement of the impeller in the direction orthogonal to the rotation axis (radial direction). For example, when a reluctance type magnetic sensor is used, this sensor is affected not only by the surface information of the opposing impeller but also by its surroundings. That is, this rotational shaft position detection sensor (position sensor) is disposed so as to completely face the axial end surface of the impeller within the radial movable range of the impeller, but in reality the radial end (inner diameter and Even if there is no displacement of the impeller in the axial direction under the influence of both the outer diameter), if the displacement occurs in the radial direction, the sensor output is affected.
Although the threshold value varies depending on the centrifugal liquid pump device, a case where the sensor detects an axial movement of 30 to 70% of the clearance between the impeller and the housing is conceivable. The clearance indicates a distance in each axial direction between the impeller and the housing in a normal use state.
[0032]
FIG. 11 shows a block diagram of a centrifugal liquid pump apparatus having an impeller low rigidity state detection using the output of the position sensor 42 and an impeller flying position control function using the impeller low rigidity state. Here, as the centrifugal liquid pump, as shown in FIGS. 2 to 5, an impeller is controlled by three sets of electromagnets and a position sensor, and the control axes are three of z, θx, and θy. Is the axis. In the case of an equilibrium point which is an impeller floating position considered to be necessary in advance, for example, a middle magnet, a permanent magnet side than the middle, and an electromagnet side from the middle (a patient requiring a large flow rate (a patient with a large body)), power consumption increases. In order to lengthen the activity time in the case of battery driving force, it is necessary to reduce the power consumption, and this is a control system for three points (used to reduce the power consumption by setting the equilibrium point to the electromagnet side). The target value is checked by adjustment, and the data is written in the nonvolatile memory 61. Normally, the intermediate position is set as the equilibrium point, and the data from the CPU 62 is converted into analog values by the DA converter 63 to obtain command values. In this embodiment, the control unit includes a nonvolatile memory 61, a CPU 62, a DA converter 63, and an AD converter 64.
[0033]
The acceleration that the user receives in daily life is considered to be 10 G or less. However, when the user receives more G due to vibration or impact, the magnetically levitated impeller may contact the inner wall of the housing. In order to prevent this, G may be detected or a physical quantity corresponding to it may be detected to increase the bearing rigidity. In order to directly detect G, it is necessary to install a dedicated acceleration sensor in the pump, but in the centrifugal liquid pump device of the present invention, the output of the position sensor is used.
[0034]
The outputs of the sensors S1, S2 and S3 during operation are digitally converted by the A-D converter 64 and input to the CPU 62, and the sensor output is output a predetermined number of times (for example, 3 times) within a predetermined time (for example, 1 minute). When the threshold value is exceeded, the impeller is judged to be in a low rigidity state, and a function of moving the equilibrium point (impeller floating position) to the permanent magnet side is provided in order to increase the rigidity.
Specifically, the CPU monitors the output of the sensor with an A / D converter during operation, and within a predetermined time (for example, 1 minute), the sensor output is a predetermined number of times (for example, 3 times) and a threshold value (impeller of the impeller). In order to increase the rigidity when exceeding a predetermined position in the vertical direction and exceeding this, the equilibrium point (impeller floating position) is moved to the permanent magnet side. Thereafter, after a predetermined time (for example, 15 minutes), the resetting is once performed, and the impeller is returned to the original position.
[0035]
Further, as the control unit, the outputs of the sensors S1, S2, and S3 are digitally converted and input to the CPU by the A / D converter 64, and the speed from the displacement per unit time and the acceleration from the speed per unit time are constantly obtained. When the acceleration threshold value is exceeded (for example, instantaneous value is 5G), the impeller may be determined to be in a low rigidity state, and a function of moving the equilibrium point to the permanent magnet side in order to increase rigidity may be provided. . Also in this case, the equilibrium point (impeller floating position) is moved to the permanent magnet side (motor side) in order to increase rigidity when the threshold value is exceeded. Thereafter, after a predetermined time (for example, 15 minutes), the resetting is once performed, and the impeller is returned to the original position.
[0036]
【The invention's effect】
A centrifugal liquid pump device according to the present invention includes a housing having a liquid inflow port and a liquid outflow port, and a first magnetic body and a second magnetic body therein, and the centrifugal liquid pump rotates when rotating inside the housing. A centrifugal liquid pump unit having an impeller for feeding liquid by force, a rotor including a magnet for attracting the first magnetic body of the impeller of the centrifugal liquid pump unit, and a motor for rotating the rotor An impeller rotational torque generating unit, an impeller position control unit including an electromagnet for attracting the second magnetic body of the impeller, and a position sensor for detecting the position of the impeller, Centrifugal liquid pump device having a centrifugal liquid pump device main body rotating in a non-contact state with an impeller, and a control device for the centrifugal liquid pump device main body The control device includes a motor rotation speed monitoring function and a storage function for storing an impeller low-rigidity rotation speed area, and the motor rotation speed detected by the rotation speed monitoring function is stored in the storage function. When the impeller is in a low-rigidity rotational speed region, the impeller low position is moved by moving the impeller to the rotor side and the motor rotational speed detected by the rotational speed monitoring function is stored in the storage function. An impeller flying position control function for returning the flying position of the impeller to the position before the change is provided when the rotation speed is out of the rigid rotation speed region.
For this reason, it normally operates in a low power consumption state, and when the rigidity of the centrifugal liquid pump is lowered due to the specific speed range of the impeller, it is corrected so that the rigidity is automatically improved by the impeller flying position control function. The impeller can be rotated in a stable state.
[0037]
In addition, the centrifugal liquid pump device of the present invention includes a housing having a liquid inflow port and a liquid outflow port, and a first magnetic body and a second magnetic body therein, and rotates in the housing. A centrifugal liquid pump unit having an impeller for feeding liquid by centrifugal force of the rotor, a rotor including a magnet for attracting the first magnetic body of the impeller of the centrifugal liquid pump unit, and rotating the rotor An impeller rotational torque generator including a motor, an impeller position controller including an electromagnet for attracting a second magnetic body of the impeller, and a position sensor for detecting the position of the impeller, A centrifugal liquid pump device main body that rotates in a non-contact state with the impeller, and a control device for the centrifugal liquid pump device main body. When the impeller low-rigidity state is detected by the impeller low-rigidity state detection function using the position sensor output and the impeller low-rigidity state detection function, the control device detects the impeller low-rigidity state. In addition, an impeller flying position control function is provided that moves the impeller floating position to the rotor side and returns the impeller floating position to the position before the change after a predetermined time has elapsed.
For this reason, it normally operates in a low power consumption state, and when the rigidity of the centrifugal liquid pump is reduced due to impeller blowout, it is corrected so that the rigidity is automatically improved by the impeller flying position control function. Can rotate the impeller.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of a centrifugal liquid pump apparatus according to the present invention.
FIG. 2 is a front view of an example of a main body of a centrifugal liquid pump device used in the centrifugal liquid pump device of the present invention.
FIG. 3 is a plan view of the centrifugal liquid pump device main body shown in FIG. 2;
4 is a longitudinal sectional view of the centrifugal liquid pump device main body of the embodiment shown in FIG. 2. FIG.
5 is a cross-sectional view taken along the line AA of the centrifugal liquid pump device main body of FIG. 2. FIG.
FIG. 6 is an explanatory diagram for explaining what the centrifugal liquid pump device main body shown in FIGS. 2 to 5 is replaced with a physical model;
FIG. 7 is a block diagram for explaining a control system of an embodiment of the centrifugal liquid pump apparatus of the present invention.
FIG. 8 is an explanatory diagram for explaining the relationship between the frequency and rigidity of the impeller in the centrifugal liquid pump device.
FIG. 9 is an explanatory diagram for explaining a relationship between the frequency and rigidity of the impeller in the centrifugal liquid pump device.
FIG. 10 is an explanatory diagram for explaining an impeller flying position control function in the centrifugal liquid pump device;
FIG. 11 is a block diagram of a centrifugal liquid pump apparatus having an impeller low-rigidity state detection using an output of a position sensor and an impeller flying position control function using the detection.
FIG. 12 is a flowchart for explaining the operation of a control unit in the centrifugal liquid pump apparatus according to the embodiment of the present invention.
[Explanation of symbols]
1 Centrifugal liquid pump device
2 Centrifugal liquid pump
3 Impeller rotational torque generator
4 Impeller position controller
5 Centrifugal liquid pump device body
6 Control device
21 Impeller
25 Magnetic material
31 rotor
34 Motor
41 electromagnet

Claims (3)

A housing having a liquid inflow port and a liquid outflow port, and an impeller that includes a first magnetic body and a second magnetic body inside, rotates inside the housing, and feeds liquid by centrifugal force during rotation. A centrifugal liquid pump unit, a rotor including a magnet for attracting the first magnetic body of the impeller of the centrifugal liquid pump unit, an impeller rotational torque generating unit including a motor for rotating the rotor, and the impeller An impeller position control unit including an electromagnet for attracting the second magnetic body, and a position sensor for detecting the position of the impeller, and the impeller rotates in a non-contact state with respect to the housing Centrifugal liquid pump device comprising a main body of a liquid pump device and a control device for the main body of the centrifugal liquid pump device. And a storage function for storing the impeller low-rigidity rotational speed region, and the motor rotational speed detected by the rotational speed monitoring function falls within the impeller low-rigidity rotational speed region stored by the storage function. When the impeller floating position is moved to the rotor side, and the motor rotational speed detected by the rotational speed monitoring function is outside the impeller low-rigid rotational speed region stored by the storage function A centrifugal liquid pump device comprising an impeller flying position control function for returning the flying position of the impeller to a position before the change. The control device includes an impeller low-rigidity state detection function that detects an impeller low-rigidity state using an output of the position sensor, and the impeller floating position control function uses the impeller low-rigidity state detection function to detect an impeller low-rigidity state. And a function of moving the impeller floating position to the rotor side and returning the impeller floating position to a position before the change after a predetermined time has elapsed. The centrifugal liquid pump device according to 1. A housing having a liquid inflow port and a liquid outflow port, and an impeller that includes a first magnetic body and a second magnetic body inside, rotates inside the housing, and feeds liquid by centrifugal force during rotation. A centrifugal liquid pump unit, a rotor including a magnet for attracting the first magnetic body of the impeller of the centrifugal liquid pump unit, an impeller rotational torque generating unit including a motor for rotating the rotor, and the impeller An impeller position control unit including an electromagnet for attracting the second magnetic body, and a position sensor for detecting the position of the impeller, and the impeller rotates in a non-contact state with respect to the housing Centrifugal liquid pump device comprising a main body portion of a liquid pump device and a control device for the main body portion of the centrifugal liquid pump device. An impeller low-rigidity state detection function that detects an impeller low-rigidity state by using an output of the position sensor; and when the impeller low-rigidity state is detected by the impeller low-rigidity state detection function, the impeller floating position is set to the rotor The centrifugal liquid pump device is provided with an impeller floating position control function for moving the impeller to a position before the change after the predetermined time has elapsed.

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