JP2003070906A - Actuator for artificial pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator for an artificial pump of which the energy efficiency is improved. SOLUTION: The actuator is provided with an impeller 120 rotated by driving of a motor 123 and a housing 121 having a first port 121a which sucks or delivers a liquid medium with the rotation of the impeller 120 and a second port 121b which delivers or sucks the liquid medium with the rotation of the impeller 120 and forming a flow passage 124 for the liquid medium between the impeller 120 and the housing 121. At the outer periphery of the impeller 120, a plurality of impeller parts 122 are formed so as to make the liquid medium flow in the rotating direction of the impeller 120 when rotating the impeller 120 and to produce a vortex flow in the radial direction of the impeller 120. The impeller parts 122 have gradually varying parts 122A reducing their width in an axial direction from the inner periphery of the impeller 120 to the outer periphery of it, and have linear part 122B vertical to the rotation axis of the impeller 120 at the outermost periphery of the impeller 120.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator having a pump function for inhaling or delivering a liquid medium, and more particularly to a blood pump used for an artificial heart or the like and a balloon pump for assisting the heart function. The present invention relates to an actuator for driving an artificial pump.

[0002]

2. Description of the Related Art Conventionally, as an actuator used in an artificial pump such as an artificial heart system, a turbomachine, Vol. 29, No. 1, 28 issued on January 10, 2001 by Nippon Kogyo Publishing Co., Ltd. There is a technique described from page to page 29. Here, one port of the hydraulic pump, which is an actuator, is connected to the blood pump for the left heart and the other port is connected to the blood pump for the right heart, and the oil flow direction is reversed by driving the hydraulic pump forward and reverse. A technique for alternately pulsating the left and right blood pumps is disclosed.

In the hydraulic pump disclosed as the above-mentioned prior art, an impeller is fixed to one end of a rotor of an electric motor, and a flow path is formed between the impeller and the housing. The housing is provided with two ports for inflow and outflow of hydraulic pressure, respectively, and a partition plate is provided between the two ports for restricting the flow of the liquid medium in the rotation direction due to the rotation of the impeller. A plurality of blades are formed on the outer peripheral part of the impeller, and the liquid medium flows into the flow passage from one of the inflow and outflow ports as the impeller rotates, and the pressure increases while drawing a vortex flow by the blades. , The liquid medium in the flow path flows out from the other of the inflow and outflow ports. Then, the artificial pump is pulsated by controlling the energization of the coil to rotate the impeller forward and backward.

[0004]

The actuator for an artificial pump is required to have a small size and a high output, and the vortex flow generated when the impeller rotates is increased to increase the inflow / outflow capability of the liquid medium with respect to the rotation of the impeller, that is, the efficiency. Must be secured. Therefore, in the above-mentioned conventional technique, the groove on the outer circumference of the impeller forming the blade portion is deeply formed to the inner peripheral side of the blade portion. Thereby, the axial dimension of the blade portion formed on the impeller of the hydraulic pump is designed to be constant (that is, the sectional shape of the blade portion along the plane including the rotation axis of the impeller is rectangular).

However, in the cross-sectional shape of the vane portion of the prior art described above, when the impeller rotates, a large vortex flow is generated in the entire flow passage, but the inner peripheral portion of the vane portion is affected by the large vortex flow due to the deep groove. The large vortex flow and the small vortex flow in the opposite direction stagnant and the liquid medium stays in the inner peripheral part of the blade, and as a result, the liquid medium is not efficiently sucked in or delivered but the liquid medium flows in. There was a problem that the output capacity (efficiency) could not be improved. Therefore, it is a technical object of the present invention to provide an artificial pump actuator capable of improving the efficiency as much as possible in order to solve the above problems.

[0006]

SUMMARY OF THE INVENTION In order to solve the above technical problems, the invention of claim 1 provides a drive source, an impeller rotated by the drive of the drive source, and a liquid medium in association with the rotation of the impeller. An actuator for an artificial pump comprising: a first port for inhaling or delivering and a second port for delivering or inhaling a liquid medium in association with rotation of an impeller, and a housing forming a flow path of the liquid medium with the impeller. In the outer periphery of the impeller, a plurality of blade portions are formed to cause the liquid medium to flow in the rotation direction of the impeller when the impeller rotates and to generate a swirl flow of the liquid medium in the radial direction of the impeller. Has a gradually changing portion in which the width in the axial direction becomes narrower from the inner circumference to the outer circumference of the impeller, and is perpendicular to the rotation axis of the impeller at the outermost circumference of the impeller. And to have a line portion.

The operation of the actuator of claim 1 will be described. When the drive source drives, the impeller rotates. When the impeller rotates, the blade medium formed on the outer circumference of the impeller causes the liquid medium to flow in the flow direction of the impeller in the flow path, and also causes the liquid medium to flow in a vortex shape in the radial direction of the impeller, generating a so-called vortex flow. . The vortex flow generated in the radial direction of the impeller increases the pressure of the liquid medium in the flow path,
The liquid medium having the increased pressure receives the flow in the rotation direction of the impeller, and delivers the liquid medium from the first port. Further, the liquid medium is sucked from the second port. When the direction of energization of the coil is reversed from this state, the rotor rotates in the opposite direction, the impeller rotates in the opposite direction, the liquid medium is delivered from the second port, and the liquid medium is sucked in from the first port.

The flow of the liquid medium in the vane portion accompanying the suction and delivery of the liquid medium will be further described. According to the invention of claim 1,
Since the blade portion has a gradually changing portion in which the width in the axial direction becomes narrower from the inner circumference of the impeller to the outer circumference, stagnation due to a small vortex is less likely to occur on the inner circumference side of the impeller, and the impeller It becomes difficult for the liquid medium to stay in the inner peripheral portion of the blade portion during the rotation of. Furthermore, at the outermost circumference of the impeller, which is the part that is reliably affected by a large vortex flow, a large vortex flow generated when the impeller rotates is secured by forming a straight part so that the cross-sectional area of the blade itself does not become large. is doing. Therefore, according to the structure of the vane portion described in claim 1, the gradual change portion promotes the increase of the pressure of the liquid medium due to the vortex flow generated when the impeller rotates without waste, and secures the large vortex flow in the linear portion. be able to. From the above, it is possible to improve the ability (efficiency) of delivering and sucking the liquid medium with respect to the rotation of the impeller.

The invention of claim 2 is a specific description of the shape of the blade portion of claim 1, wherein the axial width of the gradually changing portion is narrowed from the inner peripheral side to the outer peripheral side of the impeller. That is, it gradually became smaller as it moved to. According to the second aspect, by changing the ratio in which the axial width of the gradually changing portion is narrowed, stagnation does not occur on the inner peripheral side of the vane portion during rotation of the impeller, and on the outer peripheral side of the gradually changing portion. A large vortex flow can be secured, which is preferable from the viewpoint of efficiency.

The invention of claim 3 also specifically describes the blade portion of claim 1 or 2, wherein the straight line portion is 10% or more of the radial length of the blade portion. According to the third aspect, the radial length of the straight line portion is defined, which is suitable for securing a large vortex flow generated when the impeller rotates.

The invention of claim 4 is the invention of claims 1 to 3.
The blade portion shown in Fig. 2 is specifically described, and the gradually changing portion has one end in the axial direction of the impeller and the other end in the axial direction of the impeller so that the linear portion of the blade portion is substantially the center in the axial direction of the impeller. That is, it is formed on both sides. According to claim 4, since the gradually changing portions are formed on both sides of the blade portion in the axial direction, it is possible to generate a vortex flow on both sides of the impeller in the axial direction, thereby significantly increasing the pressure of the liquid medium in the flow path. It becomes possible to increase. This improves the ability (efficiency) of sucking and delivering the liquid medium with respect to the rotation of the impeller, and is suitable for application to an artificial pump that is desired to be downsized.

The invention of claim 5 is a specific description of claim 4, wherein the radial length of the blade portion formed on one end side in the axial direction of the impeller and the radial length of the impeller on the other end side in the axial direction. That is, the length of the blade portion is different from that in the radial direction. According to the fifth aspect, it is possible to change the radial lengths of the blade portions on both sides in the axial direction of the impeller, depending on the characteristics required for the actuator and design problems.

Further, when changing the radial lengths of the blades on both axial sides of the impeller, the gradually changing portion formed on one axial end of the impeller and the axial direction of the impeller as described in claim 6. If the length in the radial direction is the same as that of the gradually changing portion formed on the other end side, it is possible to promote the increase in the pressure of the liquid medium due to the vortex flow on both sides in the axial direction of the impeller without waste.

The invention of claim 7 is from claim 1 to claim 6.
The dimension of the vane shown in Fig. 2 is defined by the flow passage cross-sectional area of the impeller, the radial length of the vane with respect to one axial end of the impeller, the radial length of the vane with respect to the other axial end of the impeller, and the vane The representative dimension of the flow path obtained as a value obtained by dividing by the value obtained by adding the axial length of the above is 4.2 mm or more and less than 5.6 mm. According to this, it has become possible to sufficiently secure the characteristics required for the actuator for the artificial pump.

The artificial pump in the present invention is used as a general term for pumps for assisting or substituting heart function. Therefore, this artificial pump includes a blood pump for controlling the blood flow, a balloon pump for assisting the heart function by expanding and contracting according to the pulsation of the heart, and the like. As the liquid medium, it is desirable to use a liquid that has low viscosity and has little effect on the living body.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to embodiments. FIG. 1 is an overall schematic view of an artificial pump drive mechanism 1 including an artificial pump actuator according to the present embodiment. In the present embodiment, an example in which a blood pump is adopted as an artificial pump will be described. As shown in FIG. 1, in the drive mechanism 1 according to the present embodiment, an isolator 11, a hydraulic pump 12 as an actuator for an artificial pump, a motor 123, a control device 13, and a reservoir tank 14 are arranged inside a casing 100. It is configured. The isolator 11 has a space formed therein, and the space has flexibility.
1 defines a primary side chamber 112 and a secondary side chamber 113. In this embodiment, fluororubber is used as the diaphragm 111.

The hydraulic pump 12 and the motor constituting the artificial pump actuator will be described. 2 is a top view of the hydraulic pump 12 and the motor 123, and FIG. 3 is a sectional view taken along the line AA of FIG. In the present embodiment, the motor 123 corresponds to the drive source of claim 1, and the hydraulic pump is provided with the configuration other than that of claim 1. Motor 123
Is arranged so as to be rotatable relative to the stator 126 that houses the coil 126A, and has an impeller 1 at one end.
20 is fixed, and a rotor 127 having a permanent magnet 127A arranged on the outer periphery thereof is provided. The end of the coil 126A is connected to the control circuit 13 via the connector 128.

The hydraulic pump 12 is used for pulsating the blood pump 51, and sucks or delivers the liquid medium in accordance with the rotation of the impeller 120.
1a and a housing 121 having a second port 121b for sending or sucking the liquid medium in accordance with the rotation of the impeller 120 and forming a flow path 124 for the liquid medium with the impeller 120. A partition plate 125 is provided between the first port 121a and the second port 121b to regulate the flow of the liquid medium in the rotation direction accompanying the rotation of the impeller 120. On the outer circumference of the impeller 120, the impeller 1
Forty blades 122 are formed so as to flow the liquid medium in the rotation direction of the impeller 120 and to generate a swirl flow of the liquid medium in the radial direction of the impeller 120 when the 20 is rotated. The first port 121a communicates with the primary side chamber 112 of the isolator 11 through the pipe 21. The second port 121b is connected to the reservoir tank 1 through the pipe 22.
It communicates with 4. This motor 123 is used for the impeller 120.
Can be rotated in the direction indicated by arrow A in the drawing or can be rotated in the direction indicated by arrow B in the drawing. further,
The rotation speed can also be variable.

A primary pressure sensor 31 is attached to the primary chamber 112 of the isolator 11, and a secondary pressure sensor 32 is attached to the secondary chamber 113. The pressure in the primary chamber measured by the primary pressure sensor 31 and the pressure in the secondary chamber measured by the secondary pressure sensor 32 are transmitted to the control circuit 13. Secondary side chamber 1 of the isolator 11
13 is connected to the blood pump 51 through the pipe 23. Further, in the middle of the pipe 23, a supply / exhaust on-off valve 41
Is attached. The supply / exhaust on-off valve 41 is an ON-OFF valve and plays a role of adjusting the amount of air in the pipe 23 to be appropriately maintained.

The control circuit 13 is electrically connected to the motor 123 for driving the hydraulic pump 12 and the supply / exhaust on-off valve 41. Then, the pressure in the primary chamber 112 measured by the primary pressure sensor 31, the pressure in the secondary chamber 113 measured by the secondary pressure sensor 32, and others,
Based on necessary information such as the user's condition, a signal regarding the rotation direction and the rotation speed of the hydraulic pump 12 is sent to the motor 123, and an ON / OFF signal for the air supply / exhaust on / off valve 41 is output.

The blood pump 51 comprises a housing 511 and a diaphragm 512 mounted in the housing 511. Due to this diaphragm 512, the space inside the housing 511 becomes a fluid chamber 513 and a blood chamber 514.
It is divided into and. The secondary chamber 113 of the isolator 11 is connected to the fluid chamber 51 of the blood pump 51 by the pipe 23.
It communicates with the 3 side. Primary side chamber 11 of the isolator 11
Silicone oil having a kinematic viscosity of 1.5 cSt is enclosed in 2, the pipe 21, the hydraulic pump 12, the pipe 22, and the reservoir tank 14 as a liquid having a low viscosity and little influence on the living body. Air is enclosed in the secondary chamber 113 of the isolator 11, the pipe 23, and the fluid chamber 513 of the blood pump 51. Therefore, in this embodiment, the primary fluid on the upstream side (hydraulic pump 12 side) of the diaphragm 111 of the isolator 11 is silicon oil, and the secondary fluid on the downstream side (blood pump 51 side) is air. .

The operation of the blood pump driving device 1 having the above structure will be described. A control signal from the control circuit 13 is transmitted to the motor 123, and the motor 123 is driven. For example, the impeller 120 of the hydraulic pump 12 is driven in the direction indicated by arrow A in the drawing (counterclockwise rotation). Forward rotation, the oil in the hydraulic pump 12 is sent out to the riser tank 14 through the pipe 22, and the oil in the primary chamber 112 of the isolator 11 is passed through the pipe 21 to the hydraulic pump from the first port 121a. 1
2 is inhaled. Therefore, the primary chamber 112 of the isolator 11 is decompressed, and the diaphragm 111 in the isolator 11 moves leftward in the drawing (direction of arrow D) to reduce the volume of the primary chamber 112 and expand the volume of the secondary chamber 113. . The secondary chamber 113 is decompressed as its volume expands, but this pressure decrease is caused by the pipe 23.
Is transmitted to the fluid chamber 513 of the blood pump 51 communicating with the. Therefore, the fluid chamber 513 tries to reduce the volume by reducing the pressure, and the curvature of the diaphragm in the blood pump 51 is reversed from the concave state to the convex state when viewed from the fluid chamber 513 side.
The reversal of the curvature causes a pulsation, and the blood is sent into the blood chamber 514.

Further, for example, the impeller 1 of the hydraulic pump 12
When 20 is driven to rotate in the direction indicated by the arrow B (clockwise direction) in the reverse direction, the oil in the reservoir tank 14 is pumped up to the hydraulic pump 12 through the pipe 22, and the oil in the hydraulic pump 12 becomes the first oil. The primary side chamber 112 of the isolator 11 from the port 121a through the pipe 21
Sent to. Therefore, the pressure in the primary chamber 112 is increased, and the diaphragm 111 in the isolator 11 moves to the right (the direction of arrow C) in the drawing to expand the volume of the primary chamber 112 and reduce the volume of the secondary chamber 113. Secondary side room 1
The pressure of the blood pump 13 increases as the volume of the blood pump 13 decreases, and this increase in pressure causes the blood pump 5 to communicate with the secondary chamber 113 via the pipe 23.
1 is transmitted to the fluid chamber 513. Therefore, the fluid chamber 513
Tries to increase the pressure by expanding the volume, and the curvature of the diaphragm in the blood pump 51 is reversed from the convex state to the concave state when viewed from the fluid chamber 513 side. This reversal of the curvature causes a pulsation, and the blood is discharged from the blood chamber 514.

By repeating the above operation, the pulsation of blood by the blood pump is repeated. Therefore, since the cycle of the forward / reverse rotation operation of the hydraulic pump 12 becomes the pulsation cycle of the blood pump, the pulsation rate is determined by the forward / reverse rotation cycle of the hydraulic pump 12.

Next, the impeller 120 which is the gist of the present invention
The shape of the blade portion 122 formed on the above will be described in more detail. FIG. 4 is an enlarged view of the periphery of the blade portion 122 in the cross-sectional view of FIG. The blade portion 122 is the impeller 12
In the outermost circumference of the impeller 120, a straight line portion 1 that is perpendicular to the rotation axis of the impeller 120 is provided at the outermost circumference of the impeller 120.
22B respectively. Further, the gradually changing portion 122A has a radial length L1 (6.0 m) so that the straight portion 122B of the blade portion 122 becomes the center in the axial direction of the impeller 120.
m) is formed on both the one end side in the axial direction of the impeller 120 and the other end side in the axial direction of the impeller 120 indicated by the radial length L3 (6.0 mm).

In the present embodiment, the radial length of the blade portion 122 formed on the one end side of the impeller 120 in the axial direction is 9.
0 mm (L1 + straight line portion 122B: 3.0 mm), and the radial length of the blade portion 122 formed on the other end side in the axial direction of the impeller 120 is 7.0 mm (L3 + straight line portion 122B:
1.0 mm). As shown in FIG. 4, the radius of curvature on the outer peripheral side of the gradually changing portion 122A is gradually changing.
It is designed to be larger than the radius of curvature of the inner peripheral side of 22A. That is, the rate at which the axial width of the gradually changing portion 122 </ b> A of the blade portion 122 becomes narrower gradually decreases as the impeller 120 moves from the inner peripheral side to the outer peripheral side. Here, the radial length (L) of the gradually changing portion 122A formed at one axial end of the impeller 120 and the gradually changing portion 122A formed at the other axial end of the impeller 120 (L
1, L3) and the radius of curvature are the same, and impeller 120
The radial length L2 (3.0 mm) of the linear portion 122B formed on one axial side of the shaft and the radial length L4 of the linear portion 122B formed on the other axial side of the impeller 120.
(1.0 mm) is different.

The flow passage cross-sectional area of the impeller 120 (106 mm
² ) is the blade portion 1 with respect to one end side in the axial direction of the impeller 120
22 in the radial direction (L1 + L2) and the radial length of the blade portion 122 with respect to the other axial end of the impeller 120 (L3 +).
L4) and the axial length H (6.0 mm) of the blade portion 122 (L1 + L2 + L3 + L4 + H = 22.0 m)
The typical dimension of the flow path obtained as a value divided by m) is about 4.
Each dimension of the blade portion 122 is set to be 8 mm.

When the impeller 120 rotates, the flow path 124
Inside, the liquid medium flows in the rotation direction of the impeller 120, and as shown by the arrow in FIG. 3, the liquid medium flows spirally in the radial direction of the impeller 120, generating a so-called vortex flow.
The vortex flow increases the pressure of the liquid medium in the flow path 124, and the liquid medium having the increased pressure receives the flow in the rotational direction of the impeller 120 and delivers the liquid medium from the first port or the second port. , The liquid medium is sucked from the second port or the first port.

According to the blade portion 122 having the structure of the present embodiment, since the blade portion 122 has the gradually changing portion 122A, the stagnation due to a small vortex flow is less likely to occur on the inner peripheral side of the blade portion 122,
When the impeller 120 rotates, the liquid medium is less likely to stay in the inner peripheral portion of the blade 122. Further, at the outermost circumference of the impeller 120, which is a portion that is reliably affected by a large vortex flow, a straight line portion 122B is formed so that the cross-sectional area of the blade portion 122 itself does not become large.
It ensures a large vortex flow that occurs during rotation. Therefore, the gradually changing portion 122A can promote the increase of the pressure of the liquid medium due to the vortex flow generated when the impeller 120 rotates, and the straight portion 122B can secure a large vortex flow. From the above, impeller 1
Liquid medium delivery and suction capability (efficiency) for 20 rotations
It becomes possible to improve. The artificial pump actuator according to the present embodiment is 1200 rpm, 160
FIG. 5 shows a characteristic curve relating to the head when rotating at 0 rpm and 2000 rpm, and FIG. 6 shows a characteristic curve relating to efficiency. The characteristics shown in FIGS. 5 and 6 are characteristics of the hydraulic pump 12 itself, which does not include motor efficiency.

In particular, in the present embodiment, the representative dimension of the flow path is set to about 4.8 mm to further promote the above effect. That is, in the present embodiment, both the shape of the vane portion 122 of the impeller 120 and the representative dimension of the flow path are used to determine the shape shown in FIG.
And the characteristics shown in FIG. 6 are obtained. Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, a pump other than a blood pump is used as the artificial pump, or a drive source of an artificial pump actuator. Alternatively, a drive source other than the motor may be used.

Furthermore, in this embodiment, the isolator 1 is used.
Although an example in which an artificial pump actuator is adopted as a mechanism for driving the blood pump 51 by using 1 is shown, the first port 121a of the artificial pump actuator as shown in FIG. Blood pump for heart 51A
In addition, the second port 121b is directly connected to the right heart blood pump 51B, and the motor 123 is driven in the forward and reverse directions to normally and reversely rotate the impeller 120 and to reverse the flow direction of the liquid medium. You may employ | adopt to the mechanism of the system which pulsates the pumps 51A and 51B alternately. In such a mechanism, it is necessary to consider embedding the hydraulic pump 12 and the motor 123 in the body, and therefore, it is desired that the actuator for an artificial pump has a small size and high output. Since the efficiency of the artificial pump actuator of the present invention is improved as described above, it is possible to sufficiently cope with the blood pump drive mechanism of the type embedded in the heart as shown in FIG. 7. .

[0032]

As described above, according to the present invention,
The gradually changing part promotes the increase of the pressure of the liquid medium due to the vortex flow generated when the impeller rotates without waste, and
A large vortex flow can be secured by the straight part.
From the above, it is possible to improve the ability (efficiency) of delivering and sucking the liquid medium with respect to the rotation of the impeller.

[Brief description of drawings]

FIG. 1 is an overall schematic diagram of a blood pump drive mechanism that employs an artificial pump actuator according to an embodiment of the present invention.

FIG. 2 is a top view of the artificial pump actuator according to the embodiment of the present invention.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a partially enlarged view of FIG.

FIG. 5 is a characteristic curve relating to a lift of the artificial pump actuator according to the present embodiment.

FIG. 6 is a characteristic curve relating to the efficiency of the artificial pump actuator according to the present embodiment.

FIG. 7 is a schematic view showing another type of blood pump drive mechanism that employs the artificial pump actuator of the present invention.

[Explanation of symbols]

1. Blood pump drive 11 ... Isolator 111 ... Diaphragm (defining member) 112 ... Primary side room 113 ... Secondary chamber 12 ... Hydraulic pump (actuator for artificial pump) 121 ... Housing 122 ... Impeller 123 ... Motor 13 ... Control device 14 ... Reservoir tank 41 ・ ・ ・ Open / close valve for air supply 51 ... Blood pump 51A ... Blood pump for left heart 51B ... Blood pump for right heart

Claims (7)

[Claims] 1. A drive source, an impeller that is rotated by the drive of the drive source, a first port that sucks or delivers a liquid medium in accordance with the rotation of the impeller, and a liquid medium that is delivered in accordance with the rotation of the impeller, or An actuator for an artificial pump, comprising: a housing having a second port for inhaling and forming a flow path of a liquid medium between the impeller and the impeller; A plurality of vane portions are formed to cause the liquid medium to flow in the rotational direction of the impeller and to generate a swirl flow of the liquid medium in the radial direction of the impeller, and the vane portion is an axis extending from the inner circumference to the outer circumference of the impeller. It has a gradually changing portion whose width in the direction becomes narrower and a straight line portion which is perpendicular to the rotation axis of the impeller at the outermost periphery of the impeller. Wherein, the actuator for an artificial pump. 2. The ratio of the axial width of the gradually changing portion of the vane portion that becomes narrower gradually decreases as the impeller moves from the inner peripheral side to the outer peripheral side. The artificial pump actuator according to 1. 3. The artificial pump actuator according to claim 1, wherein the straight line portion is 10% or more of a radial length of the blade portion. 4. The gradually changing portions are provided on both one end side in the axial direction of the impeller and the other end side in the axial direction of the impeller so that the straight line portion of the vane portion is substantially in the center in the axial direction of the impeller. It is formed, The actuator for artificial pumps in any one of Claim 1 thru | or 3 characterized by the above-mentioned. 5. A radial length of a blade portion formed on one end side in the axial direction of the impeller and a radial length of a blade portion formed on the other end side in the axial direction of the impeller are different from each other. The artificial pump actuator according to claim 4. 6. The radial length of a gradually changing portion formed on one axial side of the impeller and the gradually changing portion formed on the other axial side of the impeller are the same in radial direction. The artificial pump actuator according to claim 5. 7. The flow passage cross-sectional area of the impeller is defined by a radial length of the blade portion with respect to one axial end of the impeller, a radial length of the blade portion with respect to the other axial end of the impeller, and an axial direction of the blade portion. The representative dimension of the flow path obtained as a value divided by the value obtained by adding the length is 4.2 mm or more and 5.6 mm.
The artificial pump actuator according to any one of claims 1 to 6, which is less than.