JP2004245303A - Artificial heart pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an artificial heart pump capable of preventing hemolysis and thrombus from being generated while maintaining stability and durability of blood supplying. <P>SOLUTION: A plurality of radial dynamic generating grooves 40, a plurality of front side thrust dynamic pressure generating grooves 41, and plurality of rear side dynamic pressure grooves generating 42 formed in a shaft portion 20 forming a bearing 2, a front side plate portion 21, and a rear side plate portion 22 comprises deep first dynamic pressure generating grooves 40a, 41a, 42a, and shallow second dynamic pressure generating grooves 40b, 41b, 42b respectively. During a rotation of an impeller 3, a part of a blood pumped flows as a lubricating fluid in small gaps Q1-Q3 defined by a sleeve 30 which is integral with the impeller 3, the shaft portion 20, the front side plate portion 21, and the rear side plate portion 22, the flowing quantity of the blood increases by the first dynamic pressure generating grooves 40a, 41a, 42b, and effective dynamic pressure is generated in the blood by the second dynamic pressure generating grooves 40b, 41b, 42b. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a centrifugal artificial heart pump that takes in and pumps blood as a substitute or assist for a living heart.
[0002]
[Prior art]
In general, as shown in FIG. 8, a centrifugal artificial heart pump is roughly supported by a housing 1, a bearing 2 fixed in the housing 1, and a rotatable support in the housing 1 with respect to the bearing 2. The impeller 3 is adapted to take in blood from the front in the axial direction and to pump the blood radially outward by rotation of the impeller 3 (for example, see Patent Document 1).
[0003]
Specifically, the housing 1 is formed by combining the front housing 10 and the rear housing 11 and integrated by welding, bonding with an adhesive, a bolt, or the like to form an internal space. At the front end of the front housing 10, a suction-side connection port 12 for taking in blood from the outside into the housing 1 is provided on the axis of the bearing 2 which will be described in detail later, while the front housing 10 or the rear housing 11 ( In FIG. 8, one side of the front housing 10) is provided with a discharge-side connection port 13 for sending blood from inside the housing 1 to the outside. That is, by the rotation of the impeller 3, blood is sucked from the suction side connection port 12 and taken into the housing 1, and the blood is separated into a gap P between a front shroud 32 and a rear shroud 31 of the impeller 3, which will be described in detail later. (Hereinafter, it may be referred to as “inner impeller flow path”), and a main blood flow path is formed in which the pressure is increased and sent out from the discharge side connection port 13.
[0004]
The bearing 2 is provided with a tubular shaft portion 20 for restricting radial movement of the impeller 3, which will be described in detail later, and is disposed so as to project radially outward from front and rear ends of the shaft portion 20, respectively. The disk-shaped front plate portion 21 and the rear plate portion 22 for regulating thrust movement of the front plate portion 21 and the outer surface, that is, the front surface of the front plate portion 21, flow toward the rear in the axial direction taken in from the suction side connection port 12. The inlet P of the channel P in the impeller, which will be described in detail later, ₁ A tip 23 having a curved surface with a raised central portion for feeding the front plate 23, the front plate 21, the shaft 20, the rear plate 22, and the rear end of the rear housing 11 from the tip 23. 24, which are integrally fixed in the housing 1 by welding, an adhesive, a bolt, or the like.
[0005]
The impeller 3 has an inner peripheral surface that is a through hole that faces the outer peripheral surface of the shaft portion 20 with a minute gap therebetween, and a front surface that opposes each inner surface of the front plate portion 21 and the rear plate portion 22 with a minute gap therebetween. A sleeve 30 of a ceramic sintered body having a rear surface, a rear shroud 31 in which the sleeve is coaxially inserted, and a front shroud 32 coaxial with the front shroud 32 at a predetermined gap in front of the rear shroud 31. And a plurality of blades 33 provided in the gap between the front shroud 32 and the rear shroud 31 for inhaling blood and increasing the pressure, which are integrally molded, shrink-fitted, brazed, adhesive, or the like. It is integrated by joining. That is, the impeller 3 (sleeve 30) is rotatable with respect to the bearing 2 (the shaft portion 20, the front plate portion 21, and the rear plate portion 22) integrated with the housing 1, and with the rotation of the impeller 3, Thus, it is desired for an artificial heart pump that takes in blood from the front in the axial direction, and pumps the blood radially outward while increasing the pressure by the blades 33 in the gap between the front shroud 32 and the rear shroud 31, which is the flow path P in the impeller. The function is obtained.
[0006]
The rotation of the impeller 3 is performed using, for example, a magnetic force. Specifically, as shown in FIG. 8, at the rear of the rear shroud 31, a permanent magnet 34 is housed in an annular groove 31c formed, and this is sealed and fixed by a lid 35, while the rear magnet is fixed. At the rear part of the housing 11, a rotating magnetic field generator 14 connected to an external or built-in power supply is disposed at a coaxial position covering the periphery of the permanent magnet 34. As a result, the rotating magnetic field generator 14 supplied with power from the power supply generates a rotating magnetic field, and the permanent magnet 34 tries to rotate around its axis synchronously by receiving the magnetic force. It rotates with respect to 2.
[0007]
Here, a lubrication mechanism for smoothly rotating the impeller 3 with respect to the bearing 2 will be described with reference to FIGS. As shown in FIG. 9, with the rotation of the impeller 3, a radially inward entrance P ₁ Exit P radially outward from ₂ , But the blood is boosted by the blades 33 in combination with the action of the centrifugal force. Therefore, the pressure acting on the blood is ₁ Exit P than ₂ Is higher and the entrance P ₁ And exit P ₂ Between the pressure differences.
[0008]
For this reason, the outlet P in the impeller passage P ₂ A part of the blood spouted from the inner wall of the rear housing 11 and the outer wall of the rear shroud 31 are introduced into the gap between the inner wall of the rear housing 11 and the minute gap between the inner surface of the rear plate portion 22 and the rear surface of the sleeve 30. Q ₁ , A minute gap Q between the outer peripheral surface of the shaft portion 20 and the inner peripheral surface of the sleeve 30. ₂ And a minute gap Q between the inner surface of the front plate portion 21 and the front surface of the sleeve 30. ₃ Through the inlet P in the impeller flow path P ₁ And eventually merges with the blood taken into the housing 1 from the suction-side connection port 12 (see the dotted arrow in FIG. 9). In other words, during the rotation of the impeller 3, the minute gap Q between the impeller 3 (sleeve 30) and the bearing 2 (the shaft 20, the front plate 21, and the rear plate 22). ₁ ~ Q ₃ Then, the blood flows, and this blood is used as a lubricating fluid.
[0009]
However, since a radial radial load and an axial thrust load are applied to the rotating impeller 3, the impeller 3 is supported by the small gap Q ₁ ~ Q ₃ The following innovations have been made to ensure
[0010]
First, as shown in FIGS. 9 to 11, a radial dynamic pressure generating groove 140 for supporting a radial load of the impeller 3 (sleeve 30) is formed on the outer peripheral surface of the shaft portion 20 that constitutes the bearing 2. (Refer to the single hatched portion in FIG. 10). These radial dynamic pressure generating grooves 140 have a spiral shape called a spiral groove, and are uniformly processed at a substantially constant depth.
[0011]
Second, a plurality of front thrust dynamic pressure generating grooves 141 for supporting the thrust load of the impeller 3 are provided on the inner surface of the front plate portion 21 as shown in FIGS. 9 and 12 to 14. I have. These front-side thrust dynamic pressure generating grooves 141 have a spiral shape and, like the radial dynamic pressure generating grooves 140, are uniformly processed to have a substantially uniform depth. On the other hand, a plurality of rear thrust dynamic pressure generating grooves 142 for supporting the thrust load of the impeller 3 are similarly provided on the inner surface of the rear plate portion 22. FIG. 12 shows a mode in which the front thrust dynamic pressure generating groove 141 or the rear thrust dynamic pressure generating groove 142 is partially provided on each inner surface of the front plate portion 21 or the rear plate portion 22. Reference numeral 13 denotes a mode provided so as to be continuous from the outer periphery or outer edge on each inner surface of the front plate portion 21 or the rear plate portion 22 to the inner periphery, that is, the outer peripheral surface of the shaft portion 20.
[0012]
By taking such measures, the rotating impeller 3 applies radial dynamic pressure and thrust to blood flowing through the radial dynamic pressure generation groove 140, the front thrust dynamic pressure generation groove 141, or the rear thrust dynamic pressure generation groove 142. Since a dynamic pressure is generated and is maintained in a non-contact state floating with respect to the bearing 2, smooth rotation becomes possible, which leads to improvement in stability and durability of blood supply as an artificial heart pump. .
[0013]
[Patent Document 1]
JP-A-7-136247 (page 2-3, FIG. 1)
[0014]
[Problems to be solved by the invention]
By the way, in the artificial heart pump, since the target fluid to be handled is blood and the target to be used is a human or an animal, it is strongly demanded that a hemolysis and a thrombus not be caused for a long period of time as a fatal problem. You. Hemolysis is a phenomenon in which the surface film of red blood cells in blood is damaged and its function is lost, and thrombus is a phenomenon in which blood aggregates and blocks blood channels such as blood vessels.
[0015]
However, in the above-described artificial heart pump, the minute gap Q formed by the sleeve 30 forming the impeller 3 and the shaft portion 20, the front plate portion 21, and the rear plate portion 22 forming the bearing 2. ₁ ~ Q ₃ , Hemolysis and thrombosis occurred frequently. Because this small gap Q ₁ ~ Q ₃ Conventionally, since a very narrow gap size of several μm to several tens of μm has been set, the blood itself is difficult to flow, and in terms of hemolysis, the relative rotational speed difference of the impeller 3 with respect to the bearing 2 depends on the rotational speed difference. This is because a great amount of shear stress acts on flowing blood, and this shear stress damages red blood cells. In addition, thrombus is not only affected by the surface roughness and affinity of the material at the place where the flowing blood comes into contact, but also occurs when the flow speed of the blood itself is slow or the flow amount is small and the blood clogs. It is thought that the small gap Q ₁ ~ Q ₃ Is extremely disadvantageous.
[0016]
As a method for solving such a problem of hemolysis and thrombus, a micro gap Q is used. ₁ ~ Q ₃ It is conceivable to simply increase the gap size of. However, if it is enlarged too much, the effectiveness of the radial dynamic pressure and the thrust dynamic pressure for supporting the radial load and the thrust load of the rotating impeller 3 is significantly reduced, and thereby the blood supply as an artificial heart pump is performed. The smooth rotation of the gear 3 with respect to the bearing 2 which leads to the stability and durability of the bearing is hindered, and the gap size is limited to about 30 μm to 40 μm. In practice, this can sufficiently solve the problems of hemolysis and thrombus. Did not.
[0017]
Therefore, the present invention has been made in view of the above problems, and has as its object to provide an artificial heart pump that can suppress the occurrence of hemolysis and thrombus while maintaining the stability and durability of the blood supply. Things.
[0018]
[Means for Solving the Problems]
To achieve the above object, an artificial heart pump according to the present invention comprises a housing, a bearing fixed in the housing, and comprising a shaft portion, a front plate portion and a rear plate portion projecting radially outward from the shaft portion. Along with a through hole facing the outer peripheral surface of the shaft portion with a minute gap therebetween, the front plate portion, a front surface facing the inner surface of the rear plate portion with a minute gap therebetween, and a rear surface facing the inner surface of the rear plate portion. And an impeller rotatably supported in the housing, and by taking in blood from the front in the axial direction and pumping the blood radially outward by rotation of the impeller, A part is introduced into the minute gap between the inner surface of the rear plate portion and the rear surface of the impeller, the minute gap between the outer peripheral surface of the shaft portion and the through hole of the impeller, and the inner surface of the front plate portion. The feather An artificial heart pump that merges with the blood taken in through a minute gap with the front surface of the shaft, wherein a plurality of radial dynamic pressure generating grooves for supporting a radial load of the impeller are provided on an outer peripheral surface of the shaft portion. The front plate portion, the inner surface of the rear plate portion, a plurality of front thrust dynamic pressure generating grooves for supporting the thrust load of the impeller, a plurality of rear thrust dynamic pressure generating grooves are provided, At least one of each of the radial dynamic pressure generating groove, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove is the other of the radial dynamic pressure generating groove, the front thrust dynamic pressure generating groove, and the rear side. It is characterized in that the depth is deeper than the side thrust dynamic pressure generating groove.
[0019]
This allows a large amount of blood to be allowed in the deep radial dynamic pressure generating groove, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove, so that a part of the pumped blood flows as a lubricating fluid. In the minute gap between the inner surface of the plate portion and the rear surface of the impeller, the minute gap between the outer peripheral surface of the shaft portion and the through hole of the impeller, and the minute gap between the inner surface of the front plate portion and the front surface of the impeller, the blood itself is used. , And the occurrence of hemolysis and thrombus is suppressed. Moreover, in the other radial dynamic pressure generating grooves, the front thrust dynamic pressure generating grooves and the rear thrust dynamic pressure generating grooves, the radial dynamic pressure and the thrust dynamic pressure are effectively generated in the flowing blood. Rotation becomes possible, and the stability and durability of the blood supply as an artificial heart pump are maintained.
[0020]
Here, from the viewpoint of practicality, the radial dynamic pressure generating groove having a large depth, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove are the other radial dynamic pressure generating grooves, It is preferable that the depth is at least 10 times deeper than the thrust dynamic pressure generating groove and the rear thrust dynamic pressure generating groove.
[0021]
Further, in order to more effectively suppress the occurrence of hemolysis and thrombus, from the viewpoint of increasing the flow amount of blood itself, the radial dynamic pressure generating groove having a large depth, the front thrust dynamic pressure generating groove, and the rear side The thrust dynamic pressure generating groove is preferably wider than the other radial dynamic pressure generating grooves, the front thrust dynamic pressure generating grooves, and the rear thrust dynamic pressure generating grooves.
[0022]
Further, in order to ensure the generation of effective radial dynamic pressure and thrust dynamic pressure, and to facilitate the flow of blood itself, the radial dynamic pressure generating groove is spiral, and the front thrust dynamic pressure generating groove and the rear The side thrust dynamic pressure generating groove is spiral, and the radial dynamic pressure generating groove having a large depth is continuous from the inner surface of the rear plate portion to the inner surface of the front plate portion in the shaft portion, The front-side thrust dynamic pressure generating groove and the rear-side thrust dynamic pressure generating groove having a large depth are continuous between outer edges of the front plate portion and the rear plate portion and the outer peripheral surface of the shaft portion. Good.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
The present inventors have maintained the stability and durability of the blood supply as an artificial heart pump with respect to the prevention of hemolysis and thrombus in the minute gap between the impeller and the bearing, which is a fatal problem of the artificial heart pump. As a result, the present invention focuses on various types of dynamic pressure generating grooves formed in a bearing for rotatably supporting the impeller in a floating state in the above-described minute gap. I've reached the point.
[0024]
In other words, a major feature of the artificial heart pump of the present invention is that a plurality of radial dynamic pressure generating grooves, a front thrust dynamic pressure generating groove, and a rear dynamic Each of the pressure generating grooves has a shallow depth and a deep depth, and the shallow depth flows to maintain the stability and durability of the blood supply as an artificial heart pump. It generates the effective dynamic pressure on the blood to ensure smooth rotation of the impeller with respect to the bearings, while the deep one plays the role of securing the flow rate of the blood itself to prevent hemolysis and thrombus formation. Fulfill.
[0025]
Hereinafter, embodiments of the artificial heart pump of the present invention will be described in detail with reference to the drawings. First, a first embodiment of the present invention will be described. FIG. 1 is a schematic view illustrating a lubrication mechanism of the artificial heart pump according to the first embodiment, FIG. 2 is a development view of a shaft outer peripheral surface showing a radial dynamic pressure generating groove of a bearing in the artificial heart pump, and FIG. FIG. 4 is a cross-sectional view of a shaft outer peripheral surface showing a cross section orthogonal to the radial dynamic pressure generating groove in FIG. 4. FIG. 4 is a front plate (or rear plate) inner surface showing a thrust dynamic pressure generating groove of a bearing of the artificial heart pump. FIG. 5 is a circumferential cross-sectional view of the inner surface of the front plate portion showing a cross section orthogonal to the thrust dynamic pressure generating groove in FIG. In the drawings, parts having the same names and the same functions as those in FIGS. 8 and 9 are denoted by the same reference numerals, and overlapping description will be omitted here, and different points will be described. The same applies to a second embodiment described later.
[0026]
In the first embodiment, first, as shown in FIGS. 1 to 3, a radial movement for supporting the radial load of the impeller 3 (sleeve 30) is provided on the outer peripheral surface of the shaft portion 20 that constitutes the bearing 2. A plurality of (six in FIG. 2) pressure generating grooves 40 are provided partially. These radial dynamic pressure generating grooves 40 have a spiral shape called a spiral groove, and are processed to have a substantially constant depth in each case.
[0027]
Here, the radial dynamic pressure generating groove 40 is composed of a pair of first radial dynamic pressure generating grooves 40a (see double hatched portions in FIG. 2) arranged at symmetrical positions, and a second radial dynamic pressure generating groove 40a disposed therebetween. The radial dynamic pressure generating groove 40b (see a single hatched portion in FIG. 2) has a depth sa of the first radial dynamic pressure generating groove 40a larger than a depth sb of the second radial dynamic pressure generating groove 40b. It is deeply formed. For example, the depth sa of the first radial dynamic pressure generating groove 40a is about 500 μm to 600 μm, while the depth sb of the second radial dynamic pressure generating groove 40b is about several tens μm.
[0028]
Also, as shown in FIGS. 1, 4 and 5, a plurality of front thrust dynamic pressure generating grooves 41 for supporting the thrust load of the impeller 3 are partially formed on the inner surface of the front plate portion 21 (FIG. 4). In the figure, six are provided). These front-side thrust dynamic pressure generating grooves 41 have a spiral shape and, like the radial dynamic pressure generating grooves 40, are individually processed to have a substantially constant depth.
[0029]
Here, the front thrust dynamic pressure generating groove 41 is composed of a pair of first front thrust dynamic pressure generating grooves 41a (see double-hatched portions in FIG. 4) arranged at symmetrical positions, and a second thrust dynamic pressure generating groove 41 disposed therebetween. The second front thrust dynamic pressure generating groove 41b (see the single hatched portion in FIG. 4), the depth ta of the first front thrust dynamic pressure generating groove 41a is equal to that of the second front thrust dynamic pressure generating groove 41b. It is formed deeper than depth tb. For example, the depth ta of the first front-side thrust dynamic pressure generating groove 41a is approximately 500 μm to 600 μm, like the depth sa of the first radial dynamic-pressure generating groove 40a, while the second front thrust dynamic pressure The depth sb of the generation groove 41b is about several tens μm, like the depth sb of the second radial dynamic pressure generation groove 40b.
[0030]
Further, a plurality of rear thrust dynamic pressure generating grooves 42 for supporting the thrust load of the impeller 3 are provided on the inner surface of the rear plate portion 22 in a similar manner. The pressure generating groove 42 includes a first front thrust dynamic pressure generating groove 42a having a large depth and a second front thrust dynamic pressure generating groove 41b having a small depth.
[0031]
By configuring the various dynamic pressure generating grooves in this way, the first radial dynamic pressure generating groove 40a, the first front thrust dynamic pressure generating groove 41a, and the first rear side, which are deep dynamic pressure generating grooves, are formed. Since a large amount of blood can be tolerated in the thrust dynamic pressure generating groove 42a, a part of the pumped blood flows as a lubricating fluid, a sleeve 30 forming the impeller 3, a shaft portion 20 forming the bearing 2, a front plate portion 21 and A minute gap Q formed by the rear plate portion 22 ₁ ~ Q ₃ In, the flow rate of the blood itself increases, and the occurrence of hemolysis and thrombus is suppressed. In addition, the second radial dynamic pressure generating groove 40b, the second front thrust dynamic pressure generating groove 41b, and the second rear thrust dynamic pressure generating groove 42b, which are shallow dynamic pressure generating grooves, reduce the flow of blood. Since the radial dynamic pressure and the thrust dynamic pressure are effectively generated, the impeller 3 can smoothly rotate with respect to the bearing 2, and the stability and durability of the blood supply as the artificial heart pump can be maintained.
[0032]
In order to secure a practical flow amount of blood itself that can suppress the occurrence of hemolysis and thrombus, the first radial dynamic pressure generating groove 40a, the first front thrust dynamic pressure generating groove 41a, and the first The depth sa, ta of the side thrust dynamic pressure generating groove 42a is equal to the depth of the second radial dynamic pressure generating groove 40b, the second front thrust dynamic pressure generating groove 41b, and the second rear thrust dynamic pressure generating groove 42b. It is preferably 10 times or more deeper than sb and tb.
[0033]
In addition, in order to more effectively suppress the occurrence of hemolysis and thrombus, from the viewpoint of increasing the flow amount of blood itself, the first radial dynamic pressure generation groove 40a shown in FIGS. The widths ua and va of the pressure generation groove 41a and the first rear thrust dynamic pressure generation groove 42a are the second radial dynamic pressure generation groove 40b, the second front thrust dynamic pressure generation groove 41b, and the second rear thrust. It is preferable that the width is wider than the widths ub and vb of the dynamic pressure generation grooves 42b.
[0034]
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a developed view of a shaft outer peripheral surface showing a radial dynamic pressure generating groove of a bearing in the artificial heart pump according to the second embodiment, and FIG. 7 is a front plate portion showing a thrust dynamic pressure generating groove of the bearing in the artificial heart pump. FIG. 4 is a plan view of an inner surface (or a rear plate portion). The feature of the second embodiment is that the first radial dynamic pressure generating groove 40a, the first front thrust dynamic pressure generating groove 41a, and the first rear thrust dynamic pressure generating groove 42a in the first embodiment are deformed, The point is that it facilitates the flow of blood itself.
[0035]
That is, the first radial dynamic pressure generating groove 40a is formed so as to be continuous between the front and rear ends of the shaft portion 20, that is, from the inner surface of the rear plate portion 22 to the inner surface of the front plate portion 21, as shown in FIG. Have been. As shown in FIG. 7, the first front-side thrust dynamic pressure generating groove 41 a is formed so as to be continuous from the outer edge of the front plate portion 21 to the outer peripheral surface of the shaft portion 20. Further, the first rear-side thrust dynamic pressure generating groove 42 a is formed in a similar manner so as to be continuous from the outer edge of the rear-side plate portion 22 to the outer peripheral surface of the shaft portion 20. Therefore, the blood itself easily and continuously flows along the first radial dynamic pressure generating groove 40a, the first front thrust dynamic pressure generating groove 41a, and the first rear thrust dynamic pressure generating groove 42a. It is possible to more effectively suppress hemolysis and thrombus.
[0036]
Incidentally, the second radial dynamic pressure generating groove 40b does not reach the front and rear ends of the shaft portion 20, and the second front thrust dynamic pressure generating groove 41b and the second rear thrust dynamic pressure generating groove 42b are formed by the front plate. Although it does not reach the outer edge of each of the portion 21 and the rear plate portion 22, there is no problem in generating effective radial dynamic pressure and thrust dynamic pressure.
[0037]
In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the second radial dynamic pressure generating groove 40b is formed to be continuous to the front and rear ends of the shaft portion 20, and the second front thrust dynamic pressure generating groove 41b and the second rear thrust dynamic pressure generating groove 42b are Of course, it may be formed continuously from the outer edge of each of the front plate portion 21 and the rear plate portion 22 to the outer peripheral surface of the shaft portion 20. Further, the front-side thrust dynamic pressure generating groove 41 and the rear-side thrust dynamic pressure generating groove 42 are not limited to the spiral shape as described above, and may be, for example, radial.
[0038]
【The invention's effect】
As described above, according to the artificial heart pump of the present invention, a bearing including a housing, a front plate portion, and a rear plate portion fixed within the housing and projecting radially outward from the shaft portion. Along with a through hole facing the outer peripheral surface of the shaft portion with a minute gap therebetween, the front plate portion, a front surface facing the inner surface of the rear plate portion with a minute gap therebetween, and a rear surface facing the inner surface of the rear plate portion. And an impeller rotatably supported in the housing, and by taking in blood from the front in the axial direction and pumping the blood radially outward by rotation of the impeller, A part is introduced into the minute gap between the inner surface of the rear plate portion and the rear surface of the impeller, the minute gap between the outer peripheral surface of the shaft portion and the through hole of the impeller, and the inner surface of the front plate portion. Of the impeller In an artificial heart pump that merges with the blood to be taken in through a minute gap with a surface, a plurality of radial dynamic pressure generating grooves for supporting the radial load of the impeller are provided on an outer peripheral surface of the shaft portion. A plurality of front thrust dynamic pressure generating grooves and a plurality of rear thrust dynamic pressure generating grooves for supporting the thrust load of the impeller are provided on the inner surfaces of the front plate portion and the rear plate portion, respectively. At least one of each of the dynamic pressure generating groove, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove is the other of the radial dynamic pressure generating groove, the front thrust dynamic pressure generating groove, and the rear side. The depth is deeper than the thrust dynamic pressure generating groove. In other words, the deep radial dynamic pressure generating groove, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove allow a large amount of blood, so that a part of the pumped blood flows as a lubricating fluid. In each of the minute gaps formed by the bearings, the flow amount of the blood itself increases, thereby suppressing the occurrence of hemolysis and thrombus. Moreover, in the other radial dynamic pressure generating grooves, the front thrust dynamic pressure generating grooves, and the rear thrust dynamic pressure generating grooves, since the radial dynamic pressure and the thrust dynamic pressure are effectively generated in the flowing blood, the impeller is smoothly moved with respect to the bearing. Rotation becomes possible, and as a result, stability and durability of the blood supply as an artificial heart pump can be maintained.
[0039]
Here, the radial dynamic pressure generating groove having a large depth, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove are other radial dynamic pressure generating grooves, the front thrust dynamic pressure generating groove, When the depth is at least 10 times deeper than the rear thrust dynamic pressure generating groove, it is possible to sufficiently secure a practical flow amount of blood itself that can suppress the occurrence of hemolysis and thrombus.
[0040]
Further, the radial dynamic pressure generating groove having a large depth, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove are other radial dynamic pressure generating grooves, the front thrust dynamic pressure generating groove, and When the width is wider than the rear thrust dynamic pressure generating groove, the flow amount of blood itself is further increased, so that the occurrence of hemolysis and thrombus can be more effectively suppressed.
[0041]
Further, the radial dynamic pressure generating groove is helical, the front thrust dynamic pressure generating groove and the rear thrust dynamic pressure generating groove are spiral, and the radial dynamic pressure generating groove having a large depth is formed by the shaft. The front thrust dynamic pressure generating groove and the rear thrust dynamic pressure generating groove, which are continuous from the inner surface of the rear plate portion to the inner surface of the front plate portion in the portion, are deeper, the front plate portion and When continuous between the outer edge of each of the rear plate portions and the outer peripheral surface of the shaft portion, a form specific to the radial dynamic pressure generating groove, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove is provided. Therefore, effective radial dynamic pressure and thrust dynamic pressure can be generated, and the blood itself can easily flow.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a lubrication mechanism of an artificial heart pump according to a first embodiment of the present invention.
FIG. 2 is a developed view of a shaft outer peripheral surface showing a radial dynamic pressure generating groove of the bearing in the first embodiment.
FIG. 3 is a cross-sectional view of an outer peripheral surface of a shaft portion in FIG. 2;
FIG. 4 is a plan view of an inner surface of a front plate portion showing a thrust dynamic pressure generation groove of the bearing according to the first embodiment.
FIG. 5 is a circumferential sectional view of the inner surface of the front plate portion in FIG. 4;
FIG. 6 is a development view of a shaft outer peripheral surface showing a radial dynamic pressure generating groove of a bearing in the artificial heart pump according to the second embodiment of the present invention.
FIG. 7 is a plan view of an inner surface of a front plate portion showing a thrust dynamic pressure generation groove of a bearing according to a second embodiment.
FIG. 8 is a vertical sectional view showing a main part of a general artificial heart pump.
FIG. 9 is a schematic diagram illustrating a lubrication mechanism of a conventional artificial heart pump.
FIG. 10 is a developed view of a shaft outer peripheral surface showing a radial dynamic pressure generating groove of a conventional bearing.
11 is a cross-sectional view of the outer peripheral surface of the shaft in FIG.
FIG. 12 is a plan view of an inner surface of a front plate portion showing a thrust dynamic pressure generation groove of a conventional bearing.
FIG. 13 is a plan view of an inner surface of a front plate portion showing a thrust dynamic pressure generation groove of another conventional bearing.
FIG. 14 is a circumferential sectional view of the inner surface of the front plate portion in FIG. 12 or FIG.
[Explanation of symbols]
1 Housing
2 Bearing
3 impeller
10 Front housing
11 Rear housing
12 Suction side connection port
13 Discharge side connection port
14 Rotating magnetic field generator
20 Shaft
21 Front plate
22 Rear plate
23 Tip
24 axle support
30 sleeve
31 Rear shroud
32 Front shroud
33 feather
34 permanent magnet
35 Lid
40 Radial dynamic pressure generating groove
40a First radial dynamic pressure generating groove (deep dynamic pressure generating groove 40)
40b Second radial dynamic pressure generating groove (shallow dynamic pressure generating groove 40)
41 Front thrust dynamic pressure generating groove
41a First front thrust dynamic pressure generating groove (dynamic pressure generating groove 41 having a large depth)
41b Second front-side thrust dynamic pressure generating groove (shallow dynamic pressure generating groove 41)
42 Rear thrust dynamic pressure generating groove
42a First rear thrust dynamic pressure generating groove (dynamic pressure generating groove 42 having a large depth)
42b 2nd rear thrust dynamic pressure generating groove (shallow dynamic pressure generating groove 42)

Claims (4)

A housing and a bearing fixed to the housing, the front plate portion and the rear plate portion projecting radially outward from the shaft portion and facing the bearing, and facing the outer peripheral surface of the shaft portion with a small gap therebetween; Along with the through-hole, the front plate portion, a front surface facing each inner surface of the rear plate portion with a small gap, a rear surface, and an impeller rotatably supported in the housing with respect to the bearing, With the rotation of the impeller, the blood is taken in from the front in the axial direction and is pumped radially outward, and a part of the pumped blood is part of the inner surface of the rear plate portion and the impeller. Introduced into the minute gap between the rear surface and the minute gap between the outer peripheral surface of the shaft portion and the through hole of the impeller, and the minute gap between the inner surface of the front plate portion and the front surface of the impeller. To the blood In the artificial heart pump to flow,
A plurality of radial dynamic pressure generating grooves for supporting a radial load of the impeller are provided on an outer peripheral surface of the shaft portion, and a thrust load of the impeller is provided on each inner surface of the front plate portion and the rear plate portion. A plurality of front-side thrust dynamic pressure generating grooves for supporting and a plurality of rear-side thrust dynamic pressure generating grooves are provided,
At least one of each of the radial dynamic pressure generating groove, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove is the other radial dynamic pressure generating groove, the front thrust dynamic pressure generating groove, and An artificial heart pump characterized by being deeper than the rear thrust dynamic pressure generating groove. The radial dynamic pressure generating groove having a large depth, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove are the other radial dynamic pressure generating grooves, the front thrust dynamic pressure generating grooves, and the rear The artificial heart pump according to claim 1, wherein the depth is at least 10 times deeper than the side thrust dynamic pressure generating groove. The radial dynamic pressure generating groove having a large depth, the front thrust dynamic pressure generating groove, and the rear thrust dynamic pressure generating groove are the other radial dynamic pressure generating grooves, the front thrust dynamic pressure generating grooves, and the rear The artificial heart pump according to claim 1, wherein the width is wider than the side thrust dynamic pressure generating groove. The radial dynamic pressure generating groove is spiral, the front thrust dynamic pressure generating groove and the rear thrust dynamic pressure generating groove are spiral,
The deep radial dynamic pressure generating groove having a large depth is continuous from the inner surface of the rear plate portion to the inner surface of the front plate portion in the shaft portion, and the front thrust dynamic pressure generating groove having a large depth is provided. 4. The rear thrust dynamic pressure generating groove is continuous between an outer edge of each of the front plate portion and the rear plate portion and an outer peripheral surface of the shaft portion. 2. The artificial heart pump according to item 1.

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