JP2002349482A - Centrifugal pump for artificial heart - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems in a centrifugal pump for an artificial heart using a pivot bearing wherein abrasion rapidly progresses depending on a combination of materials of a pivot shaft and a pivot pad, and blood stays or coagulates in a clearance due to difference between spherical radii of the both. SOLUTION: An impeller shaft part is made a cylindrical part 1, centrifugal blades 3 are disposed in a lower part, a permanent magnet 11 is disposed in the bottom, and an impeller is rotated by a driving device that is disposed in the bottom of a casing and generates a rotating magnetic field. In the embodiment shown in Fig., the pivot bearing is disposed in the center of the bottom of the impeller, the pivot shaft 6 is disposed on the impeller side, and the pivot pad 10 is disposed on the bottom wall side of the casing. As the materials of the pivot shaft 6 and the pivot pad 10, for example, materials having different hardness are selected similarly to a combination of ceramics and ultrahigh molecular weight pump. Spherical surfaces of the pivot shaft and the pivot pad have substantially equal diameters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump for an artificial heart in which a centrifugal pump provided with a cylindrical impeller having a blood flow path formed therein is driven by a permanent magnet rotated by a motor or a rotating magnetic field formed by an electromagnet. In particular, the present invention relates to a centrifugal pump type artificial heart pump in which the thrust direction of the centrifugal pump is supported by a contact-type pivot bearing.

[0002]

2. Description of the Related Art One of the specifications required for artificial heart pumps
One is prevention of blood coagulation (thrombus). In order to prevent blood coagulation (thrombosis), it is necessary that the blood flow in the artificial heart pump has no flow obstruction or stagnation, and it is desired that the artificial heart pump can be operated stably. .

A centrifugal artificial heart pump is generally provided in a casing so as to be rotatable with the casing, and an impeller for applying centrifugal force to blood flowing through a blood flow path, and for rotating the impeller. And a blood flow path for introducing and guiding blood.

Various types of centrifugal pump-type artificial heart pumps have been conventionally proposed. However, the present inventor has proposed an artificial heart pump having a small number of structural materials that can cause a flow obstruction in a blood flow path. According to JP-A-10-33664
(Japanese Patent No. 2807786).

According to the artificial heart pump described above, an impeller 23 is formed on an impeller portion 22 formed around a lower portion of a cylindrical portion 21 with a structure as shown in FIG.
Are provided with a permanent magnet group 24 at the bottom thereof, a pivot shaft 25 protruding from the center thereof, and a magnet 26 provided on the outer periphery of the cylindrical portion 21. Such an impeller is housed in the pump chamber 20 of the casing 27, and the magnet 2 provided on the cylindrical portion 21 on the inner surface of the pump chamber 20 of the casing 27.
The supporting magnet 28 is arranged at a position opposing the position 6, and the impeller is supported in the radial direction by supporting the impeller in the radial direction by the repulsive force of both magnets.
Further, a pivot receiver 30 is provided at the center of the bottom wall 29 of the casing 27, where the spherical portion of the pivot shaft 25 of the impeller is received to support the impeller in the thrust direction. It is rotatably supported.

[0006] An impeller driving device 31 is provided below the casing 27, and a permanent magnet group 33 or a magnet group 33 for generating a rotating magnetic field is arranged inside the impeller driving device 31 to generate a rotating magnetic field. The coupling magnet group 24 rotates so that the impeller is driven to rotate, whereby blood flows in from an inlet 34 formed in the upper part of the casing and can be discharged from an outlet provided in the lower part of the casing. It has become.

[0007]

In the artificial heart pump proposed by the present inventor, the cylindrical portion connected to the upstream side of the impeller forms a blood flow channel due to the above-described structure. There is an advantage that the shape can be made simple and the cross-sectional area can be made large, and smooth blood flow can be achieved.

In the above-mentioned centrifugal pump for artificial heart proposed by the present inventor, many disadvantages of the above-mentioned conventional one can be solved by adopting the entire structure as described above. Has been studying improvement of the pump, and as a result, further improved the pivot bearing provided at the bottom of the impeller in FIG.

That is, at the beginning of the research and development of this artificial heart centrifugal pump, the radius differs between the pivot shaft and the pivot receiver, which are generally used in industry and are considered to be highly durable pivot bearings. Those using ceramics with high properties were used. As a result, a frictional resistance between the two is reduced and power consumption is reduced, and a bearing having a surface useful especially as a centrifugal pump for an artificial heart implantable in the body has been adopted.

However, in the above-described pivot bearing in which both are made of ceramics, it is assumed that the pivot shaft and the pivot receiver have been used for a long period of time, despite the use of highly durable ceramics. It has been found that abrasion powder gradually accumulates on the sliding contact surface, thereby shortening the life of the pump, as well as causing blood stagnation in the bearing portion and causing a thrombus.

The present invention has been made on the basis of the above-described findings, and produces less abrasion powder than conventional ones, and accumulates abrasion powder like the conventional one to shorten the life of the pump. A main object of the present invention is to provide a centrifugal pump for an artificial heart, which does not cause any stagnation of blood in the bearing portion.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a casing, an impeller rotatably disposed in a pump chamber of the casing, and a casing provided with the impeller. A pivot bearing that supports in the direction of the rotation axis, and a device that has a built-in permanent magnet in the impeller and that drives the permanent magnet to rotate through a partition, wherein the impeller has a blood flow path on the upstream side. Connected to the cylindrical portion to be configured, the rotation drive device is a permanent magnet group rotated by a motor, or in an artificial heart centrifugal pump configured by an electromagnet group that generates a rotating magnetic field,
A centrifugal pump for an artificial heart, characterized in that the pivot shaft and the pivot receiver of the pivot bearing are formed of members having different hardness, and the radii of the spherical surfaces of the pivot shaft and the pivot receiver are set substantially equal.

According to a second aspect of the present invention, the pivot shaft and the pivot receiver are formed of members made of different materials in a set of ceramics and ultrahigh molecular weight polyethylene. It is a centrifugal pump.

The invention according to claim 3 is the centrifugal pump for an artificial heart according to claim 1, wherein the pivot shaft of the pivot bearing is provided on the impeller side and the pivot receiver is provided on the casing side. It is.

The invention according to claim 4 is the centrifugal pump for artificial heart according to claim 1, wherein the pivot bearing of the pivot bearing is provided on the impeller side and the pivot shaft is provided on the casing side. It is.

According to a fifth aspect of the present invention, there is provided a radial bearing comprising a magnetic bearing in which magnets are arranged on the outer periphery of the cylindrical portion of the impeller and the inner periphery of the casing to oppose each other. This is a centrifugal pump for an artificial heart.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. 1 and 2 are sectional views showing the overall structure of a centrifugal pump for an artificial heart according to the present invention. It has been further improved by research and development. In FIG. 1, a centrifugal blade 3 as shown in FIG. 2 is radially formed on an impeller portion 2 formed below a hollow impeller cylindrical portion 1, and a permanent magnet group 5 is provided on a bottom portion 4 of the impeller portion 2. I have. A pivot shaft 6 protrudes from the center of the bottom 4, and is supported by a pivot receiver 10 provided on a bottom wall 8 of a casing 7.

A magnet 11 is provided on the outer periphery of the impeller cylindrical portion 1. When such an impeller is housed in the pump chamber 12 of the casing 7, the pump chamber 12 of the casing 7
A supporting magnet 12 is disposed on the inner surface at a position opposing the magnet 11 provided on the impeller cylindrical portion 1. The impeller is supported in the radial direction by the repulsive force of both magnets, the magnet 11 and the support magnet 12, and the impeller is supported in the thrust direction by the pivot receiver 10 and the pivot shaft 6.

An impeller driving device 13 is provided at a lower portion of the casing 7, and a direct drive type motor 14 is provided therein. An electromagnet is formed in a linear motor type by a coil which is sequentially excited. The permanent magnet group 5 provided at the bottom of the impeller is driven to rotate following the impeller, whereby the impeller rotates, and blood flows in from an inflow port 15 formed at the upper center of the casing 7, and the casing This can be discharged from an outlet 16 provided around the lower part of the nozzle 7.

FIG. 2 is an enlarged view of the centrifugal pump for an artificial heart having the above-described overall configuration, in which an impeller supported by a pivot bearing and a bottom wall of a casing supporting the impeller, which are main parts of the present invention, are shown. 3 and FIG. 4 is a detailed view in which the pivot bearing portion is further enlarged. As is clear from these figures, the pivot receiver 10 has a receiving part 20 formed of a concave part having an arc-shaped cross section at the center part. The radius of the receiving portion 20 of the pivot receiver and the radius of the pivot shaft 6 are substantially equal.

In the above-described pivot bearing, in the present invention, the materials of the pivot shaft and the pivot receiver having different hardnesses are used. For example, when ceramics are used for the pivot shaft, ultra high molecular weight polyethylene is used for the pivot receiver, and when ultra high molecular weight polyethylene is used for the pivot shaft, ceramics are used for the pivot receiver.

By making the hardness of the pivot shaft and the material of the pivot receiver different from each other, it is possible to prevent the generation of abrasion powder as compared with the case where both are molded with ceramics. Is known for. In addition, it has been found that by making the radius of the pivot shaft and that of the pivot receiver substantially equal, the stagnation of blood between the two can be prevented, and blood coagulation does not occur at this portion.

FIG. 5 shows an example in which the members of the pivot shaft and the pivot receiver of FIG. 4 are reversed, a pivot receiver having a concave spherical shape is provided on the impeller side, and the bottom wall 8 of the casing is provided on the bottom wall 8 side of the casing. A pivot shaft 10 having a protruding upper portion and a spherical surface having substantially the same diameter as the pivot receiver is provided. Also in this pivot bearing, the materials of the pivot shaft and the pivot receiver are different from each other in hardness, and a pair of ceramics and ultra high molecular weight polyethylene can be used in the same manner as described above.

Also, due to the above-mentioned structure, although the power consumption is increased as compared with the conventional one in which the spherical radius of the pivot shaft and the spherical radius of the pivot receiver are different, 1 W
It was found that the centrifugal pump for an implantable artificial heart had sufficient conditions.

[0025]

According to the present invention, the impeller is hollow and the hollow portion constitutes a blood flow channel, similarly to the artificial heart centrifugal pump proposed by the present inventor. Therefore, the shape of the flow path is simple and the cross-sectional area can be increased,
Not only does the blood flow easily flow smoothly, but there is no member in the blood flow path that hinders the blood flow. In addition, there is an effect that the rotation of the impeller can be stabilized by the shape of the pivot receiver.

As described above, in the artificial heart centrifugal pump according to the present invention, there is no structural material in the flow path of the blood flow which may cause a flow obstruction, and the diameter of the flow path can be increased. In the artificial heart centrifugal pump, which can be operated, has a simple structure and can be miniaturized, the generation of abrasion powder at the pivot bearing portion is reduced, and blood stays at the pivot bearing portion unlike the conventional centrifugal pump. And the occurrence of thrombus can be prevented.

Further, compared with the pivot bearing having a dynamic pressure bearing, it is not necessary to form a groove for generating dynamic pressure in the pivot bearing portion, and high machining accuracy is not required.
A pivot bearing can be easily formed,
Inexpensive devices can also be used.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a centrifugal pump for an artificial heart according to the present invention.

FIG. 2 is a cross-sectional view of the same embodiment.

FIG. 3 is a longitudinal sectional view of the vicinity of an impeller and a pivot bearing portion of the embodiment.

FIG. 4 is an enlarged sectional view of a pivot bearing portion of the embodiment.

FIG. 5 is a longitudinal sectional view showing another embodiment of the pivot bearing of the centrifugal pump for an artificial heart according to the present invention.

FIG. 6 is a longitudinal sectional view showing a main part of a centrifugal pump for an artificial heart previously proposed by the present inventors.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impeller cylinder part 2 Impeller part 3 Centrifugal blade 4 Bottom part 5 Permanent magnet group 6 Pivot shaft 7 Casing 8 Bottom wall 9 Pump room 10 Pivot receiver 11 Magnet (driven side) 12 Magnet (driving side) 13 Impeller driving device 14 Motor 15 Inlet 16 Outlet

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F04D 13/06 F04D 13/06 C 29/22 29/22 BF Term (Reference) 3H022 AA01 BA04 BA06 CA01 CA06 CA11 CA15 CA16 CA53 CA56 DA00 DA08 DA13 3H033 AA01 AA05 AA11 BB01 BB06 BB11 CC01 CC03 CC05 CC06 DD01 DD26 DD29 DD30 EE00 EE09 EE11 EE14 4C077 AA04 CC05 DD08 EE01 KK06

Claims (5)

[Claims] 1. A casing, an impeller rotatably disposed in a pump chamber of the casing, a pivot bearing for supporting the impeller in a rotational axis direction with respect to the casing, and a permanent magnet built in the impeller, A device that rotationally drives this permanent magnet through, the impeller is connected to a cylindrical portion that constitutes a blood flow path on the upstream side, and the rotational drive device is a group of permanent magnets that rotate with a motor, Alternatively, in a centrifugal pump for an artificial heart constituted by a group of electromagnets generating a rotating magnetic field, the pivot shaft and the pivot receiver of the pivot bearing are formed of members having different hardness, and the radii of the spherical surfaces of the pivot shaft and the pivot receiver are set substantially equal. Centrifugal pump for artificial hearts. 2. The centrifugal pump for an artificial heart according to claim 1, wherein the pivot shaft and the pivot receiver are formed of members made of different materials in a set of ceramics and ultra-high molecular weight polyethylene. 3. The artificial heart centrifugal pump according to claim 1, wherein the pivot shaft of the pivot bearing is provided on the impeller side and the pivot receiver is provided on the casing side. 4. The artificial heart centrifugal pump according to claim 1, wherein the pivot bearing is provided on the impeller side and the pivot shaft is provided on the casing side of the pivot bearing. 5. A radial bearing, comprising: a cylindrical portion connected to an upstream side of the impeller; and a magnetic bearing having magnets arranged on the outer periphery of the cylindrical portion and the inner periphery of the casing. The centrifugal pump for an artificial heart according to the above.