WO2006137496A1

WO2006137496A1 - Artificial heart pump with dynamic pressure bearing

Info

Publication number: WO2006137496A1
Application number: PCT/JP2006/312541
Authority: WO
Inventors: Takashi Yamane
Original assignee: National Institute Of Advanced Industrial Science And Technology
Priority date: 2005-06-23
Filing date: 2006-06-22
Publication date: 2006-12-28
Also published as: JP4517076B2; JP2007000350A

Abstract

In order not to recirculate blood serving as working fluid flowing through the gap in an impeller dynamic pressure bearing of an artificial heart pump from the delivery side of an impeller and to support the impeller body (8) only with one thrust dynamic pressure bearing, the impeller (5) is constituted of the impeller body (8) and an impeller bearing member (9), a permanent magnet (21) is arranged along the tubular surface (7), and vanes (6) are provided radially on the lower surface. An inside casing (4) is provided with a casing bearing member (17), a radial dynamic pressure bearing with a dynamic pressure groove is formed in any one of the outer circumferential surface (13) of the upper tubular portion (11) of the impeller bearing member (9) and the tubular inner circumferential surface (18) of the casing bearing member (17), and a thrust dynamic pressure bearing with a dynamic pressure groove is formed in one of the outer circumferential surface (13) of the upper surface (15) of the impeller bearing member (9) and the lower end face (19) of the casing bearing member (17). The working fluid is introduced through these dynamic pressure grooves from an impeller inlet and discharged to the impeller delivery side. During rotation, the impeller (5) is lifted and its thrust force is received only by the thrust dynamic pressure bearing arranged above.

Description

Specification

Artificial heart pump with hydrodynamic bearing

Technical field

The present invention relates to an artificial heart pump used in place of or together with a living heart, and more particularly to an artificial heart pump supported by a dynamic pressure bearing in both the radial direction and the thrust direction.

Background art

[0002] In Japan, an organ transplantation method has been implemented and heart transplantation from brain death is possible. However, since the actual situation is a shortage of donors, the way to save the remaining patients is not capable of artificial heart. Artificial heart has been studied for a long time and many clinical uses have been reported. There are two types of artificial heart: an auxiliary artificial heart that can be inserted in parallel without excising the living heart, and a complete replacement artificial heart that can be excised and combined. In the past, most of these were air-driven types with a control device installed on the bedside, but in recent years, an abdominal implant is possible, and an auxiliary artificial heart that is electrically driven using a battery attached to a belt or backpack has also been developed. In addition, the current products use an artificial heart that can be treated at home, although the size and strength of the product are limited to the patient's size.

[0003] When such artificial hearts are classified into pump-type point forces, there are roughly two types: a pulsatile flow type and a continuous flow type. The pulsatile flow type is a method in which a fixed amount of blood is sent out for each stroke, and some assistive heart prostheses with advanced clinical applications have a track record of annual use. The continuous flow type is a system in which blood is continuously sent out by a rotating mechanism, and the delivery amount is not directly related to the pump volume and is easy to miniaturize, which is promising for an implantable auxiliary artificial heart. Regarding the effects of non-pulsatile flow on living bodies, some animal experiments have reported that it survives without physiological problems. However, physiologically, pulsatile flow is preferred, and V, and therefore, a continuous flow pump is being developed as an auxiliary artificial heart that leaves a living heart. There are individual types of continuous flow pumps such as centrifugal, axial flow and rotary displacement type. The present invention relates to this continuous flow type artificial heart.

As a specific example, the present inventor has proposed a centrifugal pump for an artificial heart as shown in FIG. Patent No. 2807786 (Japanese Patent Laid-Open No. 10-33664 · Patent Document 1). According to this artificial heart pump, as shown in FIG. 3, the centrifugal impeller 42 is supported by two opposing radial bearings 46-48 and pivot bearings 45-50. An impeller driving device 51 is provided at the lower part of the casing 47, and the magnet 53 rotates inside to drive the magnet group 44 with a built-in impeller. As a result, blood flows in from the inlet 54 formed in the upper part of the casing and can be discharged from the outlet loci provided around the lower part of the casing. As a means for rotating the impeller by the magnetic coupling as described above, a direct drive type driving device in which the movable part 53 is replaced with an electromagnet group has been developed!

[0005] Furthermore, the present inventors have disclosed in Japanese Patent Laid-Open No. 2003-24434 (Patent Document 2) in order to solve the above-described problems of weight reduction of the artificial heart pump and frictional sliding at the pivot bearing portion. We are proposing an artificial heart pump that does not use the pivot bearing as described above, but operates entirely with a hydrodynamic bearing. That is, as shown in FIG. 4, in this artificial heart pump, a fixed shaft 77 projects from a lower thrust receiver 76 provided at the lower center of the lower casing 75, and an upper thrust receiver 78 is fixed to the upper end. An impeller support member 67 is provided below the impeller portion 62 provided with an inflow portion 63 in the center, and permanent magnets 81 are arranged at equal intervals on the outer periphery of the impeller support member 67. By disposing the electromagnet 82, a direct drive in- ber drive device 83 is configured. A bearing forming member 68 is provided on the center side of the impeller support member 67, and a radial dynamic pressure bearing is formed between a cylindrical inner surface and a fixed shaft 77 having a radial dynamic pressure groove 80 formed on the outer periphery thereof. Further, an upper radial dynamic pressure bearing is formed between the upper thrust dynamic pressure generating groove 73 provided on the upper end surface 72 of the impeller support member 67 and the upper thrust receiver 78, and provided on the lower end surface 68 of the impeller support member 67. A lower radial dynamic pressure bearing is configured between the lower thrust dynamic pressure generating groove 71 and the lower thrust receiver 76. In this pump, blood in the outflow portion 69 of the impeller 61 is circulated through each bearing portion using the working fluid.

[0006] With the artificial heart pump having such a configuration, the above-mentioned problems can be solved, and further, more stable rotation can be performed than the artificial heart pump described in Patent Document 3 below. It has become. Also, an artificial heart pump as described in Patent Document 4 below As described above, when the impeller is driven, a large thrust force can be eliminated by rotating the impeller while sucking it in the rotation axis direction.

Patent Document 1: Japanese Patent Laid-Open No. 10-33664

Patent Document 2: Japanese Patent Laid-Open No. 2003-24434

Patent Document 3: Japanese Patent Publication No. 2001-515765

Patent Document 4: Japanese Patent Laid-Open No. 9-206372

Disclosure of the invention

Problems to be solved by the invention

[0007] In the artificial heart pump disclosed in Patent Document 2 proposed by the present inventor, stable operation can be performed without using a pivot bearing, but the upper thrust bearing 73-78 and In both gaps of the lower thrust bearings 71-76, it is necessary to set the gap narrowly in order to perform strict position adjustment, which may adversely affect blood coagulation and blood cell destruction.

[0008] Therefore, the artificial heart pump has a problem that it requires particularly precise thrust pressure adjustment. In addition, blood is circulated as a working fluid in these dynamic pressure bearings, and the blood discharged from the impeller is recirculated through the minute gap of the force dynamic pressure bearing, which prevents the blood from coagulating. In particular, there is a possibility that blood recirculated and discharged from the impeller may be circulated again to the hydrodynamic bearing portion, which is further disadvantageous in terms of blood coagulation.

[0009] In the case of recirculation of blood discharged from the impeller to the hydrodynamic bearing, the gap of the lower thrust hydrodynamic bearing, the radial hydrodynamic bearing, and the upper thrust hydrodynamic bearing are sequentially circulated. For this reason, it passes through a large number of minute gaps, which has a large effect on blood and is disadvantageous in preventing blood coagulation. Therefore, it is desirable to reduce the number of times passing through the hydrodynamic bearing as much as possible.

[0010] The present invention has been made based on the above knowledge, and blood as an operating fluid that flows through the gap of the dynamic pressure bearing when the thrust direction and radial direction of the impeller are supported by the dynamic pressure bearing. It is possible to operate with stable operation without recirculating the discharge side force of the impeller. Means for Solving the Problems whose main purpose is to provide an artificial heart pump with a hydrodynamic bearing

[0011] In order to solve the above problems, an artificial heart pump including a hydrodynamic bearing according to the present invention has a permanent inlet having an inflow port in an upper center portion and a plurality of poles along an outer peripheral surface of a lower cylindrical portion. A magnet is disposed, and an impeller having a plurality of vanes extending radially around an opening communicating with the inlet on the lower surface side and an upper cylindrical portion protruding upward is opposed to an outer peripheral surface of a lower cylindrical portion of the impeller A dynamic pressure groove is provided in a casing in which a plurality of electromagnets are arranged on a cylindrical inner peripheral surface that is rotatably and vertically movable, and is provided on either the upper cylindrical outer peripheral surface of the impeller or the casing inner peripheral surface facing the upper cylindrical portion. A thrust dynamic pressure bearing provided with a dynamic pressure groove is formed between the upper surface of the impeller and the lower end surface of the casing facing the radial dynamic pressure bearing.

[0012] An artificial heart pump provided with another dynamic pressure bearing according to the present invention is the thrust dynamic pressure bearing provided with the dynamic pressure groove, wherein the fluid at the inlet of the impeller is used as an action of each dynamic pressure groove. In this way, it is guided to each dynamic pressure groove and flows out to the fluid discharge side of the vane.

[0013] An artificial heart pump provided with another dynamic pressure bearing according to the present invention is the thrust dynamic pressure bearing provided with the dynamic pressure groove, wherein the arrangement position of the permanent magnet in the vane is set in the casing. 2. The artificial heart pump provided with a hydrodynamic bearing according to claim 1, wherein the artificial heart pump is arranged below at least when the impeller is not rotated from the arrangement position of the electromagnet.

[0014] An artificial heart pump including another dynamic pressure bearing according to the present invention is a thrust dynamic pressure bearing including the dynamic pressure groove, wherein the impeller includes the permanent magnet inside and the vane on a lower surface side. And an impeller bearing member comprising an upper cylindrical portion and a disc portion located on the upper portion of the impeller main body, and any of the upper cylindrical portion outer peripheral surface and the casing inner peripheral surface facing the upper cylindrical portion A radial dynamic pressure bearing having a crab dynamic pressure groove is formed, and a thrust dynamic pressure bearing having a dynamic pressure groove is formed on either the upper surface of the disk portion or the lower end surface of the casing facing the disk portion. Features.

[0015] An artificial heart pump provided with another dynamic pressure bearing according to the present invention is the thrust dynamic pressure bearing provided with the dynamic pressure groove, wherein the casing is opposed to an outer peripheral surface of an upper cylindrical portion of the impeller. A casing bearing member having a facing inner peripheral surface and a lower end surface facing the upper surface of the impeller is formed separately from the casing body, and both are combined.

[0016] An artificial heart pump including another dynamic pressure bearing according to the present invention is a thrust dynamic pressure bearing including the dynamic pressure groove, wherein a bottom surface of the casing facing an end surface of the vane is A guide projection having a substantially conical surface is fixed immediately below the inlet of the impeller, and the fluid is guided by the guide projection in the direction of the center side force and the vane is operated in a semi-open vane manner. Features.

The invention's effect

[0017] Since the present invention is configured as described above, when supporting both the thrust direction and radial direction of the impeller by the dynamic pressure bearing, a part of the impeller from the inflow side of the impeller that bypasses the gap of the dynamic pressure bearing is bypassed. As a result, the fluid as a working fluid is not recirculated even by the discharge side force of the impeller through the gap of the hydrodynamic bearing and guided to the discharge side of the impeller. In particular, the thrust bearing can be supported and stably operated by only one side without providing both the upper and lower sides, the structure of the bearing can be simplified, and the cost can be reduced accordingly. The adverse effect on blood due to flowing through the gap of the pressure bearing can be reduced.

Brief Description of Drawings

FIG. 1 is a cross-sectional view of an embodiment of the present invention.

FIG. 2 is a perspective view, a plan view, and a bottom view of the impeller of the same embodiment.

FIG. 3 is a cross-sectional view of an artificial heart centrifugal pump previously proposed by the present inventors.

FIG. 4 is a cross-sectional view of an artificial heart centrifugal pump in which the present inventors have improved the pump.

Explanation of symbols

[0019] 1 Artificial heart pump

2 Lower casing

3 Upper casing

4 Inner casing Cylindrical surface

Impeller body Impeller bearing member Disk

Upper cylindrical part Lower cylindrical part Outer peripheral surface

Radial dynamic pressure groove Upper surface

Thrust dynamic pressure groove Casing bearing member Cylindrical inner peripheral surface Lower end surface

Center opening Permanent magnet Electromagnet

Vane opening Guide protrusion Inclined end face Casing upper face Lower end face

Inflow

Connection pipe

Cylindrical part

Outer flange part Bolt

Discharge passage Discharge member BEST MODE FOR CARRYING OUT THE INVENTION

[0020] The present invention has a problem that the blood as the working fluid flowing through the gap between the impeller dynamic pressure bearings is not recirculated from the discharge side of the impeller, and there is only one thrust bearing. A permanent magnet having a plurality of poles is arranged along the outer peripheral surface of the lower cylindrical portion, and a plurality of vanes extending radially around the opening communicating with the inlet are provided on the lower surface side, and project upward. An impeller having an upper cylindrical portion is provided in a casing in which a plurality of electromagnets are arranged on a cylindrical inner peripheral surface facing a lower cylindrical portion outer peripheral surface of the impeller so as to be rotatable and vertically movable, and the upper cylindrical portion of the impeller A radial dynamic pressure bearing having a dynamic pressure groove is formed on either the outer peripheral surface or the casing inner peripheral surface facing the outer peripheral surface, and the upper surface of the impeller and the lower end surface of the casing facing the same are shifted. It was solved by forming a thrust dynamic pressure bearing example Bei dynamic pressure generating grooves.

Example

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an embodiment of the present invention. In the illustrated artificial heart pump 1, as main components, a lower casing 2, an upper casing 3, and an inner casing that fits in the center of the upper casing 3. 4 and an impeller 5 rotating inside these casings.

As shown in FIG. 2, the impeller 5 is provided with four vanes 6 protruding from the lower end surface side thereof, and the outer periphery of the impeller main body 8 made of resin having a cylindrical surface 7. An impeller bearing member 9 that also has a ceramic equal force is fixed above it by press-fitting or bonding. The impeller bearing member 9 is composed of a disc portion 10 having an outer diameter that matches the cylindrical surface 7 of the impeller body 8, an upper cylindrical portion 11 protruding upward, and a lower cylindrical portion 12 protruding downward. The lower cylindrical part 12 is fitted and fixed to the upper part of the impeller body 8.

In the embodiment shown in FIGS. 1 and 2, a radial dynamic pressure groove 14 is formed on the outer peripheral surface 13 of the upper cylindrical portion 11 of the impeller bearing member 9 and the thrust dynamic pressure is applied to the upper surface 15 of the disc portion 10. A groove 16 is formed. On the other hand, a casing bearing member 17 made of ceramics or the like is fitted and fixed to the lower end of the center of the inner casing 4, and this casing bearing member 17 is fitted with the upper cylindrical portion 11 of the impeller bearing member 9 with a gap. A cylindrical inner peripheral surface 18, a lower end surface 19, and a central opening 20 are provided at the center thereof. [0024] By the impeller bearing member 9 and the casing bearing member 17 as described above, the radial dynamic pressure groove 14 of the impeller bearing member 9 faces the cylindrical inner peripheral surface 18 of the casing bearing member 17 with a gap therebetween, and the impeller The thrust dynamic pressure groove 16 of the bearing member 9 faces the lower end surface 19 of the casing bearing member 17. In the above embodiment, the force shown in the example in which all the dynamic pressure grooves are formed on the impeller bearing member 9 side is shown. Conversely, the radial dynamic pressure grooves are formed on the cylindrical inner peripheral surface 18 of the casing bearing member 17 and the lower end surface 19 is formed. A combination of forming a thrust dynamic pressure groove can be employed, and there is a combination of forming a radial dynamic pressure groove on the cylindrical inner peripheral surface 18 and forming a thrust dynamic pressure groove on the upper surface 15! /, An arbitrary combination such as a combination of forming a radial dynamic pressure groove on the outer peripheral surface 13 and forming a thrust dynamic pressure groove on the lower end surface 19 can be adopted.

In the impeller body 8, permanent magnets 21 having a plurality of poles are arranged at equal intervals inside the cylindrical surface 7 that forms the outer peripheral surface of the lower cylindrical portion of the impeller body. These permanent magnets 21 are opposed to a plurality of electromagnetic stones 22 arranged on the inner peripheral side of the upper casing 3 in the figure. In particular, in the illustrated embodiment, the center line a of the row of the plurality of permanent magnets is positioned below the center line b of the plurality of electromagnets 22 when the impeller is lowered by its own weight at least when the impeller is not rotating. When the magnetic coupling with the permanent magnet is caused by energization of the electromagnet, the entire impeller 5 can be lifted and rotated by the magnetic force, and at that time, the upper surface 15 of the disk portion 10 and the casing bearing member 17 It is close to the lower end surface 19 and can be supported by a thrust hydrodynamic bearing in the gap.

[0026] In the illustrated embodiment, the vanes 6 formed at the lower end of the impeller main body 8 are eccentric from the center of the central vane opening 23 and extend radially, and four are shown in the figure. In its assembled state, as shown in FIG. 1, it has a conical cross section fixed below the vane opening 23 and guides the blood flow flowing in the center in the pump axis direction in the outer peripheral direction. The vane 6 includes an inclined end surface 25 facing the guide protrusion 24 and a lower end surface 27 facing the casing upper surface 26 of the lower casing 2.

An inlet 28 is formed at the center of the inner casing 4, and a connecting pipe 29 is fixed to the inlet 28. Further, in the illustrated embodiment, the outer periphery of the cylindrical portion 30 that extends downward in the inner casing 4 is fitted into the center portion of the upper casing 3, thereby the upper casing 3. 3 constitutes an inner partition for a plurality of electromagnets 22 fixed on the inner peripheral side. Further, an outer peripheral flange portion 31 that extends outward from the cylindrical portion 30 of the inner casing 4 is sandwiched between the lower casing 2 and the upper casing 3, and these are integrally coupled by a bolt 32.

[0028] When the artificial heart pump 1 assembled as shown in Fig. 1 is operated as described above, when the electromagnet 22 is energized, the predetermined change in the electromagnetic force of the electromagnet 22 is the same as that of a normal motor. As a result, the permanent magnet 21 is sequentially attracted and repelled to rotate, and the impeller 5 rotates. As a result, blood in the body flowing in from the connection pipe 29 passes through the inlet 28 of the inner casing 4 through the central opening 20 of the casing bearing member 17, the through-hole 17 of the impeller bearing member 9, and the vane opening 23, respectively. It is guided in the outer circumferential direction by the section 24, and is pressurized and flowed in the outer circumferential direction by the rotating vane 6 in a semi-open vane manner, and is discharged from the discharge passage 33 of the lower casing 2 to the discharge port 35 of the discharge member 34. Can be circulated through the body.

[0029] When the electromagnet 22 is energized, the rotating impeller 5 is initially self-rotating due to the eccentricity of the electromagnet 22 and the permanent magnet in the vertical directions a and b and the force of blood flow in the vane 6. In the illustrated embodiment, a thrust dynamic pressure groove 16 formed on the upper surface 15 of the disk portion 10 of the impeller bearing member 15; The thrust force is supported by a thrust dynamic pressure bearing formed between the lower end surface 19 of the casing bearing member 17.

In addition, a radial dynamic pressure bearing formed between the radial dynamic pressure groove 14 formed on the outer peripheral surface 13 of the upper cylindrical portion 11 of the impeller bearing member 9 and the cylindrical inner peripheral surface 18 of the casing bearing member 17. It is supported in the radial direction. Therefore, in this artificial heart pump 1, the thrust bearings on both the upper and lower sides are required in the conventional pump, but in the present invention, as described above, only the thrust bearing on one side is stable. Can support rotation. When the force that moves the impeller 5 upward when the impeller 5 rotates is sufficiently obtained by the fluid pressure of the pump, the eccentricity between the electromagnet and the permanent magnet is not necessary.

At this time, by forming the above-described dynamic pressure groove sufficiently deep, a partial force of blood flowing from the central opening 20 of the casing bearing member 17 and the upper end of the impeller bearing member 9 and the case Passing through the gap 35 with the radial bearing member 17, passing through the gap in the radial bearing section, pressurized in the pump axial direction by the radial dynamic pressure groove 14, and then in the radial direction by the thrust dynamic pressure groove 16 in the gap in the thrust bearing section. Pressurized, passes through the gap between the outer peripheral surface of the disk part 10 and the outer peripheral surface 7 of the impeller body 8 and the inner peripheral surface of the cylindrical part 30 of the inner casing 4, and mixes with the discharge flow from the vane 6. And then discharge. As a result, the blood passing through each dynamic pressure bearing is not recirculated, and the occurrence of blood coagulation can be prevented.

Industrial applicability

The present invention can be effectively used as an artificial heart pump used inside and outside the body.

Claims

The scope of the claims

[1] An inlet is formed in the upper center portion, a permanent magnet having a plurality of poles is disposed along the outer peripheral surface of the lower cylindrical portion, and a plurality of radially extending portions centering on an opening communicating with the inlet on the lower surface side An impeller provided with a vane and having an upper cylindrical portion protruding upward can be rotated and moved up and down in a casing in which a plurality of electromagnets are arranged on a cylindrical inner peripheral surface facing the outer peripheral surface of the lower cylindrical portion of the impeller. Provided,

A radial dynamic pressure bearing having a dynamic pressure groove is formed on either the outer peripheral surface of the upper cylindrical portion of the impeller and the inner peripheral surface of the casing facing the impeller, and any of the upper surface of the impeller and the lower end surface of the casing facing the impeller An artificial heart pump provided with a dynamic pressure bearing, characterized in that a thrust dynamic pressure bearing provided with a crab dynamic pressure groove is formed.

[2] The dynamic pressure according to claim 1, wherein the fluid at the inlet of the impeller is guided to each dynamic pressure groove by the action of each dynamic pressure groove and flows out to the fluid discharge side of the vane. Artificial heart pump with bearings.

[3] The hydrodynamic bearing according to claim 1, wherein the arrangement position of the permanent magnet in the vane is arranged below the arrangement position of the electromagnet in the casing at least when the impeller is not rotating. Artificial heart pump equipped with.

[4] The impeller includes an impeller body including the permanent magnet therein and the vane on a lower surface side, and an impeller including the upper cylindrical portion and a disk portion positioned above the impeller body. A bearing member,

A radial dynamic pressure bearing having a dynamic pressure groove is formed on either the outer peripheral surface of the upper cylindrical portion or the inner peripheral surface of the casing facing the upper cylindrical portion, and any of the upper surface of the disc portion and the lower end surface of the casing facing the disk portion. The artificial heart pump provided with the dynamic pressure bearing according to claim 1, wherein a thrust dynamic pressure bearing including a crab dynamic pressure groove is formed.

[5] The casing includes a casing bearing member having an inner peripheral surface facing the outer peripheral surface of the upper cylindrical portion of the impeller and a lower end surface facing the upper surface of the impeller separately from the casing main body. The artificial heart pump provided with the hydrodynamic bearing according to claim 1, wherein both are combined.

[6] On the bottom surface of the casing facing the end surface of the vane, A guide projection having a substantially conical surface is fixed immediately below the inflow port, fluid is guided from the center side to the outer periphery by the guide projection, and the vane operates in a semi-open vane manner. An artificial heart pump comprising the hydrodynamic bearing according to claim 1.