JP2013053591A - Centrifugal pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal pump that reliably prevents a shaft member from swinging in a direction orthogonal to the center axis and reliably prevents or inhibits hemolysis between the shaft member and the first bearing and between the shaft member and the second bearing when a centrifugal force applying member rotates.SOLUTION: A centrifugal pump 1 includes a support mechanism 4 that rotatably supports an impeller. The support mechanism 4 includes: a shaft member 5 that has a first sphere 51 and a second sphere 52 formed at both end parts; a first bearing 6 that rotatably bears the first sphere 51; and a second bearing 7 that rotatably bears the second sphere 52. The first bearing 6 has: around-axis contact parts 61a-61c that come in contact with the first sphere 51 at three points around a center axis O; and an on-axis contact part 62 which comes in contact with the first sphere 51 at one point on the center axis O. The second bearing 7 has: around-axis contact parts 71a-71c that come in contact with the second sphere 52 at three points around the center axis O; and an on-axis contact part 72 that come in contact with the second sphere 52 at one point on the center axis O.

Description

  The present invention relates to a centrifugal pump.

  2. Description of the Related Art Conventionally, blood pumps that transport blood include turbo pumps that pump blood by centrifugal force. A hollow housing, an impeller that is rotatably housed in the housing, and a rotating shaft that serves as the center of rotation of the impeller ( A shaft member), an upper bearing that rotatably supports the upper end portion of the rotating shaft, and a lower bearing that rotatably supports the lower end portion of the rotating shaft are known (see, for example, Patent Document 1). .

  In the blood pump described in Patent Document 1, the upper bearing has a cylindrical shape, and an upper end portion of a rotating shaft having an outer diameter slightly smaller than the inner diameter is inserted. Thereby, the inner peripheral part of an upper bearing and the outer peripheral part of the upper end part of a rotating shaft are in the state of surface contact. Further, the lower bearing is also cylindrical, and the lower end portion of the rotating shaft having an outer diameter slightly smaller than the inner diameter is inserted. Thereby, the inner peripheral part of a lower bearing and the outer peripheral part of the lower end part of a rotating shaft are in the state of surface contact. In addition, the blood pump described in Patent Document 1 is provided with play on the upper bearing and the lower bearing so that the rotation shaft can be shifted vertically between the upper bearing and the lower bearing.

  However, in the blood pump described in Patent Document 1, when the impeller rotates, the rotation shaft shifts in the vertical direction by the amount of the play, and as a result, swings in the horizontal direction as well. ) This swing causes problems such as the entire blood pump unintentionally excessively vibrating.

  In the blood pump described in Patent Document 1, as described above, the inner peripheral portion of the upper bearing and the outer peripheral portion of the upper end portion of the rotating shaft are in surface contact with each other. Has occurred. Similarly, the inner peripheral portion of the lower bearing and the outer peripheral portion of the lower end portion of the rotating shaft are in surface contact with each other, and hemolysis has occurred between them.

Japanese Patent No. 4548450

  The purpose of the present invention is to reliably prevent the shaft member rotating together with the centrifugal force applying member from swinging in a direction perpendicular to the central axis when the centrifugal force applying member rotates. An object of the present invention is to provide a centrifugal pump that can reliably prevent or suppress hemolysis between each of a shaft member and a first bearing and a second bearing.

Such an object is achieved by the present inventions (1) to (9) below.
(1) A housing constituted by a hollow body, having a blood inflow port through which the blood flows in, and a blood outflow port through which the blood flowing in from the blood inflow port flows out. When,
A centrifugal force imparting member that is rotatably accommodated in the hollow portion and imparts centrifugal force to blood from the rotation,
A support mechanism that rotatably supports the centrifugal force applying member with respect to the housing;
The support mechanism is composed of a rod-like body that is installed in the center of rotation of the centrifugal force imparting member, and both end portions of the shaft member each form a rotating body around the central axis of the rod-like body, and
A first bearing that rotatably supports one end of the shaft member;
A second bearing that rotatably supports the other end of the shaft member;
The first bearing and the second bearing each have an axial contact portion that contacts at least three points around the central axis with respect to an end portion of the shaft member supported by the bearing, and the central shaft A centrifugal pump comprising an on-axis contact portion that contacts at least one point on the shaft.

  (2) The centrifugal pump according to (1), wherein one end of the shaft member and the other end of the shaft member are each a sphere.

(3) At least one of the first bearing and the second bearing is composed of a flat plate and the same number of protrusions as the pivot contact portion formed so as to protrude from one surface of the flat plate,
The centrifugal pump according to (1) or (2), wherein the flat plate functions as the on-axis contact portion, and each of the protrusions functions as the on-axis contact portion.

  (4) The centrifugal pump according to (3), wherein each of the protrusions has a round contact surface in contact with the shaft member.

(5) One end of the shaft member and the other end of the shaft member are each a sphere,
The centrifugal pump according to (3) or (4), wherein the height of each of the protrusions is larger than the radius of the sphere.

(6) One of the first bearing and the second bearing has a plate shape, and is configured by a flat plate having a recess formed on one surface thereof.
The centrifugal pump according to any one of (1) to (5), wherein a bottom surface of the recess functions as the on-axis contact portion, and an inner peripheral surface of the recess functions as the contact portion around each axis.

  (7) The centrifugal pump according to (6), wherein the concave portion has a triangular shape in plan view.

(8) Each of the one end portion of the shaft member and the other end portion of the shaft member is a sphere,
The depth of the said recessed part is a centrifugal pump as described in said (6) or (7) which is larger than the radius of the said spherical body.

  (9) The centrifugal pump according to any one of (1) to (8), wherein the contact portions around each axis are arranged at equiangular intervals around the central axis.

In the centrifugal pump of the present invention, the number of the contact points around the shaft of the first bearing and the number of contact points around the shaft of the second bearing are the same.
When viewed from the central axis direction, it is preferable that the respective shaft-contact points of the first bearing and the shaft-contact points of the second bearing overlap each other.

  In the centrifugal pump of the present invention, it is preferable that each of the first bearing and the second bearing is configured separately from the housing and is fixed to the housing.

  In the centrifugal pump according to the present invention, it is preferable that the shape of the rotating body formed by one end of the shaft member and the shape of the rotating body formed by the other end of the shaft member are the same.

  In the centrifugal pump of the present invention, it is preferable that at least one of the one end portion of the shaft member and the other end portion of the shaft member is a sphere.

  In the centrifugal pump of the present invention, it is preferable that the shaft member, the first bearing, and the second bearing are made of different materials.

  In the centrifugal pump of the present invention, it is preferable that the shaft member is made of a metal material, and the first bearing and the second bearing are each made of a resin material.

  In the centrifugal pump of the present invention, it is preferable that the centrifugal force application member has a disk shape, is formed radially from the center thereof, and has a plurality of blood flow paths through which blood passes.

  Further, in the centrifugal pump of the present invention, the housing has a flat cylindrical shape, the blood inlet is projected at one end thereof, and the blood outlet is projected at the outer peripheral portion in the tangential direction. It is preferable.

  In the centrifugal pump of the present invention, it is preferable that the shaft member is used so as to be parallel to the vertical direction.

  According to the present invention, the one end portion of the shaft member and the first bearing are in point contact, and the number of contacts can be reduced as much as possible. Further, the other end of the shaft member and the second bearing are in point contact, and the number of contacts can be reduced as much as possible.

  With such a configuration, when the centrifugal force application member rotates, the shaft member that rotates together with the centrifugal force application member is stably supported, and thus swings in a direction orthogonal to the central axis of the shaft member. Is reliably prevented. Further, the contact area between the one end portion of the shaft member and the first bearing is also reduced as much as possible, so that hemolysis between these members can be reliably prevented or suppressed. Similarly, the contact area between the other end portion of the shaft member and the second bearing is reduced as much as possible, so that hemolysis between these members can be reliably prevented or suppressed. Moreover, thrombus formation due to heat generated by friction can be suppressed.

It is a section side view showing an embodiment of a centrifugal pump of the present invention. It is a section top view showing an embodiment of a centrifugal pump of the present invention. It is a perspective view which shows the support mechanism with which the centrifugal pump of this invention is provided (The figure which shows the positional relationship of a 1st bearing and a 2nd bearing). It is the sectional view on the AA line in FIG. It is the BB sectional view taken on the line in FIG. FIG. 2 is an enlarged view of a region [C] surrounded by an alternate long and short dash line in FIG. 1. FIG. 2 is an enlarged view of a region [D] surrounded by a one-dot chain line in FIG. 1.

  Hereinafter, the centrifugal pump of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  1 is a sectional side view showing an embodiment of the centrifugal pump of the present invention, FIG. 2 is a sectional plan view showing an embodiment of the centrifugal pump of the present invention, and FIG. 3 is a support mechanism provided in the centrifugal pump of the present invention. FIG. 4 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 5 is a cross-sectional view taken along line BB in FIG. 6 and 6 are enlarged views of a region [C] surrounded by a one-dot chain line in FIG. 1, and FIG. 7 is an enlarged view of a region [D] surrounded by a one-dot chain line in FIG. Hereinafter, for convenience of explanation, the upper side in FIGS. 1, 3, 6 and 7 is referred to as “upper” or “upper”, and the lower side is referred to as “lower” or “lower”.

  A centrifugal pump 1 shown in FIG. 1 supports a housing 2 configured by a hollow body, a rotating body (impeller) 3 rotatably accommodated in the housing 2, and the rotating body 3 rotatably supported by the housing 2. And a support mechanism 4. Hereinafter, the configuration of each unit will be described.

  The housing 2 is formed of a flat cylindrical member, and includes a top plate 21 that closes the upper end and a bottom plate 22 that closes the lower end. A flat space (hollow part) surrounded by the top plate 21, the bottom plate 22, and the side wall 23 becomes the pump chamber 24.

  The housing 2 also has a blood inlet 25 through which blood Q flows and a blood outlet 26 through which blood Q flows out. The blood inlet 25 and the blood outlet 26 communicate with the pump chamber 24, respectively. Then, the blood Q that flows in from the blood inlet 25 can flow out of the blood outlet 26 via the pump chamber 24.

  As shown in FIG. 1, the blood inlet 25 is formed in a tubular shape at the center of the top plate 21 (one end). The blood inlet 25 is bent halfway in the longitudinal direction, and can be divided into a root portion 252 on the top plate 21 side and a connecting portion 253 on the opposite side with the bent portion 251 as a boundary portion. For example, a tube constituting a blood circuit can be connected to the connection portion 253.

  As shown in FIG. 2, the blood outlet 26 is formed in a tubular shape on the outer peripheral surface (outer peripheral portion) 231 of the side wall 23. The blood outlet 26 protrudes in the tangential direction of the outer peripheral surface 231 of the side wall 23.

  In the pump chamber 24 of the housing 2, a disk-shaped rotating body 3 is concentrically disposed. The rotating body 3 is a centrifugal force applying member that applies a centrifugal force to the blood Q by rotating.

  As shown in FIG. 2, the rotator 3 has a plurality (six in the illustrated configuration) of blood flow passages 31 through which the blood Q passes. These blood flow paths 31 are formed radially from the center of the rotating body 3. Further, the central side portions of the rotator 3 of each blood flow path 31 merge (intersect) with each other, and open to the upper surface 32 of the rotator 3. On the other hand, the part of the blood channel 31 opposite to the center side of the rotator 3 is open to the outer peripheral surface 33 of the rotator 3. Further, a gap 241 is formed between the outer peripheral surface 33 of the rotating body 3 and the inner peripheral surface 232 of the side wall 23 of the housing 2.

  When such a rotator 3 rotates in the clockwise direction in FIG. 2, blood Q flowing from the blood inlet 25 enters each blood channel 31 from the center side portion of the rotator 3, and centrifugal force In response, the blood channel 31 flows down. The blood Q that has flowed down flows into the gap 241. Thereafter, when the blood Q receives the clockwise rotational force in FIG. 2 within the gap 241 and reaches the blood outlet 26, the blood Q is surely discharged from the blood outlet 26.

  As shown in FIG. 1, the rotating body 3 is provided with a magnet in a lower portion of the blood flow path 31. In the configuration shown in FIG. 1, a plurality of (for example, six) permanent magnets 34 are used. When the centrifugal pump 1 is driven, the centrifugal pump 1 is mounted on an external drive means (not shown) with the bottom plate 22 of the housing 2 facing down so that a shaft member 5 described later is parallel to the vertical direction. . The centrifugal pump 1 is used in this mounted state. The external drive means has, for example, a motor and a permanent magnet connected to the motor, and this permanent magnet attracts the permanent magnet 34 built in the centrifugal pump 1 by magnetic force. And if a motor rotates in this state, the rotational force will be transmitted via the attracting magnets, and the rotary body 3 can also rotate.

  The diameter of the rotating body 3 is not particularly limited, but is preferably 20 to 200 mm, for example, and more preferably 30 to 100 mm. Although the thickness of the rotary body 3 is not specifically limited, For example, it is preferable that it is 3-40 mm, and it is more preferable that it is 5-30 mm. Although the maximum rotation speed of the rotary body 3 is not specifically limited, For example, it is preferable that it is 2000-6000 rpm, and it is more preferable that it is 2500-5000 rpm.

  Moreover, it does not specifically limit as a constituent material of the rotary body 3 and the housing 2, For example, acrylic resin, polyethylene, such as hard polyvinyl chloride, polyethylene, a polypropylene, a polystyrene, a polycarbonate, an acrylic resin, a polymethylmethacrylate (PMMA) Examples thereof include various hard resins such as polyester such as terephthalate (PET) and polybutylene terephthalate (PBT), polysulfone and polyarylate. Of these constituent materials, polycarbonate and acrylic resin are particularly preferred from the viewpoints of excellent compatibility with blood Q and excellent transparency and molding processability.

  As shown in FIG. 1, the rotating body 3 is supported to be rotatable with respect to the housing 2 via a support mechanism 4. The support mechanism 4 includes a shaft member 5 formed of a rod-shaped body having a rod shape, a first bearing 6 that rotatably supports an upper end portion (one end portion) of the shaft member 5, and a lower end portion (others) of the shaft member 5 And a second bearing 7 that rotatably supports the end portion. The shaft member 5 is installed at the rotation center of the rotating body 3. The first bearing 6 is installed and fixed to a first bearing installation part 254 formed to be recessed in the inner peripheral part of the connection part 253 of the blood inlet 25 of the housing 2. The second bearing 7 is installed and fixed to a second bearing installation portion 221 formed by being recessed in the center of the bottom plate 22 of the housing 2. The method of fixing the first bearing 6 and the second bearing 7 to the housing 2 is not particularly limited. For example, a method by fitting, a method by adhesion (adhesion with an adhesive or a solvent), or fusion (heat) A method by fusion, high frequency fusion, ultrasonic fusion, etc.), a method by insert molding, and the like.

  The shaft member 5 can be divided into a first sphere 51 on the upper end side, a second sphere 52 on the lower end side, and a columnar shaft 53 between them, depending on the shape of each part.

The first sphere 51 and the second sphere 52 are spheres having the same radii R ₁ and R ₂ . Thereby, when designing the shaft member 5, the design conditions such as the dimensions of the first sphere 51 and the second sphere 52 can be made the same, and the design can be easily performed. Further, since the “sphere” has a shape regardless of the installation angle with respect to the shaft 53, when the shaft member 5 is processed (manufactured), the processing accuracy can be made constant. The radius R ₁ and the radius R ₂ are the same in this embodiment, but are not limited to this and may be different.

The radii R ₁ and R ₂ are each preferably, for example, 0.5 to 3 mm, and more preferably _{1 to} 2.5 mm.

  The outer surface 511 of the first sphere 51 and the outer surface 521 of the second sphere 52 may be coated with, for example, diamond-like carbon (DLC), titanium, or the like. Thereby, the slidability of the 1st spherical body 51 and the 2nd spherical body 52 at the time of the shaft member 5 rotating improves.

  The shaft 53 has a reduced diameter portion 531 whose outer diameter is reduced in the middle of the longitudinal direction. The shaft 53 is connected and fixed to the rotating body 3 mainly through the reduced diameter portion 531. The fixing method is not particularly limited, and for example, a fitting method, a fusion method (thermal fusion, high frequency fusion, ultrasonic fusion, etc.), or an adhesion (adhesion with an adhesive or a solvent). Methods and the like.

  In addition, the outer diameters at both ends of the shaft 53 are smaller than the diameters of the first sphere 51 and the second sphere 52 in the present embodiment, respectively, but are not limited thereto and may be the same. And it can be large.

  As shown in FIGS. 1, 3, 4, and 6, the first bearing 6 is a member that rotatably supports the first sphere 51 of the shaft member 5. The first bearing 6 is in contact with the first sphere 51 at four points. That is, the first bearing 6 is connected to the first spherical body 51 at three points around the central axis O of the shaft member 5 at one point on the central axis O and the axial contact portions 61a, 61b, 61c. And an on-axis contact portion 62 in contact therewith.

  The on-axis contact portion 62 is configured by a disc (a flat plate). As shown in FIG. 6, the on-axis contact portion 62, which is a disc, has a lower surface 621 that is a contact surface that makes point contact with the outer surface 511 of the first sphere 51.

  Each of the shaft contact parts 61a to 61c is composed of three protrusions that are formed in a columnar shape so as to protrude downward from the lower surface 621 (one surface) of the on-axis contact part 62. As shown in FIG. 4, each of the axial contact portions 61 a to 61 c that are protrusions has a surface facing the central axis O side, that is, an inner surface 611 that points to the outer surface 511 of the first sphere 51. It is a contact surface that comes into contact. Moreover, it is preferable that the inner surface 611 is rounded so as to protrude toward the central axis O side. Thereby, when the shaft member 5 rotates, it is possible to prevent the inner surface 611 from being worn by friction generated between the outer surface 511 and the inner surface 611 of the first sphere 51.

As shown in FIG. 6, the heights H of the axial contact portions 61 a to 61 c are respectively larger than the radius R ₁ of the first sphere 51. Thus, for example, even if the shaft member 5 is slightly displaced downward, the state where the shaft contact portions 61a to 61c are in point contact with the first sphere 51 on the inner surface 611 is reliably maintained, The shaft member 5 can rotate stably.

  Further, as shown in FIG. 4, the shaft contact portions 61 a to 61 c are arranged at equiangular intervals on the central axis O. Thereby, the shaft member 5 can be stably supported with as few contacts as possible.

  As shown in FIG. 1, the first bearing 6 is installed on the first bearing installation part 254 so that the shaft contact parts 61 a to 61 c protrude into the connection part 253 of the blood inlet 25 of the housing 2. Yes. Since the shaft contact portions 61a to 61 are arranged apart from each other, the blood Q can easily pass between the shaft contact portions 61a to 61, that is, the blood flow is prevented from being inhibited. The Thereby, the retention of the blood Q in the vicinity of the upstream side of the first bearing 6 can be reliably prevented and thrombus formation can be suppressed. Further, it is possible to easily remove bubbles when filling the centrifugal pump 1 with blood at the start of use, and when bubbles are mixed in the blood Q, the bubbles can be reliably prevented from staying. .

  The first bearing 6 is preferably one in which the shaft contact portions 61a to 61c and the shaft contact portion 62 are integrally formed. However, the first bearing 6 is not limited to this, and for example, the shaft contact portions 61a to 61c and the shaft The upper contact portion 62 may be configured as separate bodies, and these separate bodies may be connected to each other. Further, when the shaft contact portions 61a to 61c and the axial contact portion 62 are configured separately, the constituent materials of the separate components may be the same or different.

  As shown in FIGS. 1, 3, 5, and 7, the second bearing 7 is a member that rotatably supports the second sphere 52 of the shaft member 5. The second bearing 7 is in contact with the second sphere 52 at four points. That is, the second bearing 7 is connected to the second spherical body 52 at three points around the central axis O of the shaft member 5 at one point on the central axis O. And an on-axis contact portion 72 in contact therewith.

The second bearing 7 is composed of a disc (flat plate) having a recess 74 formed on the upper surface 73 (one surface). As shown in FIGS. 3 and 5, the recess 74 has a substantially equilateral triangle shape in plan view.
As shown in FIG. 7, the bottom surface of the recess 74 functions as the axial contact portion 72.

  As shown in FIG. 5, the portions constituting each side of the “regular triangle” on the inner peripheral surface of the recess 74 function as the axis contact portions 71 a to 71 c, respectively. These axial contact portions 71a to 71c are arranged at equiangular intervals with respect to the central axis O. Thereby, the shaft member 5 can be stably supported with as few contacts as possible.

Further, the depth D of the recess 74 is larger than the radius R2 of the _second sphere (see FIG. 7). Thereby, for example, even if the shaft member 5 is slightly displaced in the upward direction, the state where the shaft contact portions 71a to 71c are in point contact with the second sphere 52 is reliably maintained, and thus the shaft member 5 is It can rotate stably.

  As shown in FIG. 3, when the support mechanism 4 is viewed from the direction of the central axis O, the shaft contact portion 61a of the first bearing 6 and the shaft contact portion 71a of the second bearing 7 overlap each other, The shaft contact portion 61b of the first bearing 6 and the shaft contact portion 71b of the second bearing 7 overlap each other, and the shaft contact portion 61c of the first bearing 6 and the shaft of the second bearing 7 are rotated. The contact portions 71c overlap each other. For example, the shaft member 5 can be stably rotated by such a positional relationship between the contact portions.

  As shown in FIG. 1, the first bearing 6 is configured separately from the housing 2 and is fixed to the housing 2. The second bearing 7 is also formed separately from the housing 2 and is fixed to the housing 2. Since the first bearing 6 and the second bearing 7 are configured separately from the housing 2 as described above, for example, when molding each member, it is possible to use a constituent material suitable for the molding. it can.

  In the support mechanism 4 having the shaft member 5, the first bearing 6, and the second bearing 7 as described above, the first sphere 51 of the shaft member 5 and the first bearing 6 are in point contact, and further The number of contacts can be reduced as much as possible. Further, the second sphere 52 of the shaft member 5 and the second bearing 7 are also in point contact, and the number of contacts can be reduced as much as possible.

  With such a configuration, when the rotating body 3 rotates, the shaft member 5 that rotates together with the rotating body 3 is stably supported, and thus swings in a direction orthogonal to the central axis O, that is, in the horizontal direction. It is reliably prevented from moving. Further, the contact area between the first sphere 51 of the shaft member 5 and the first bearing 6 is also reduced as much as possible, and therefore, hemolysis and thrombus formation due to friction between these members are reliably prevented (or suppressed). Can do. Similarly, the contact area between the second sphere 52 of the shaft member 5 and the second bearing 7 is also reduced as much as possible, so that hemolysis and thrombus formation due to friction between these members is reliably prevented (or suppressed). )can do.

  In addition, it is preferable that the 1st bearing 6 and the 2nd bearing 7 are comprised with the same material. Moreover, each bearing and the shaft member 5 may be comprised with the mutually same material, and may be comprised with a different material. When each bearing and the shaft member 5 are comprised with the mutually same material, a hard thing is used for each constituent material, for example, the 1st bearing 6, the 2nd bearing 7, and the shaft member 5 are each made of a metal material. Or it can comprise with ceramics. When each bearing and the shaft member 5 are made of different materials, a hard material is used as the constituent material of the shaft member 5, and a softer material than the shaft member 5 is used as the constituent material of each bearing. The shaft member 5 can be made of a metal material or ceramics, and the first bearing 6 and the second bearing 7 can be made of a resin material, respectively.

  It does not specifically limit as a resin material, For example, a thermoplastic resin is mentioned. Examples of the thermoplastic resin include polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer, modified polyolefins, polyamides (eg, nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon) 12, Nylon 6-12, Nylon 6-66), Thermoplastic polyimide, Aromatic polyester and other liquid crystal polymers, Polyphenylene oxide, Polyphenylene sulfide, Polycarbonate, Polymethyl methacrylate, Polyether, Polyetheretherketone, Polyetherimide, Polyacetal , Styrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide, polybutadiene, trans polyisoprene, fluoro rubber Various thermoplastic elastomers such as chlorinated polyethylene and the like, or copolymers, blends, polymer alloys, etc. mainly composed of these, can be used, and one or more of these can be used in combination. .

  It does not specifically limit as a metal material, For example, stainless steel etc. are mentioned. Moreover, ceramics etc. can be used besides a metal material. Moreover, it does not specifically limit as hardness (Vickers hardness (Hv)) of such a hard material (a metal material or ceramics), For example, it is preferable that it is 50 or more, and it is more preferable that it is 100 or more.

  By using such a constituent material, wear resistance between the first bearing 6 and the shaft member 5 and between the second bearing 7 and the shaft member 5 is improved.

  As mentioned above, although the centrifugal pump of this invention was demonstrated about embodiment of illustration, this invention is not limited to this, Each part which comprises a centrifugal pump is a thing of arbitrary structures which can exhibit the same function. Can be substituted. Moreover, arbitrary components may be added.

  Further, the shape of both end portions of the shaft member is spherical in the embodiment, but is not limited to this, as long as it forms a rotating body around the central axis of the shaft member. It may be conical, frustoconical, or hemispherical. In this case, for example, one end of both end portions of the shaft member may be spherical and the other end may be conical.

  Further, the first bearing is in contact with the first sphere at three contact points around the central axis of the shaft member in the embodiment, but is not limited thereto. It may be in contact with at least four contact points around the center axis of the member.

  In addition, the first bearing is in contact with the first sphere at one axial contact portion on the central axis of the shaft member in the embodiment, but is not limited thereto. It may be in contact with a plurality of on-axis contact portions on the central axis of the member.

  In addition, the inner surface of each axial contact portion in the first bearing has a rounded shape in the embodiment, but is not limited to this, for example, along the outer surface of the sphere The shape may be sufficient, and the shape which has the corner | angular part which went to the central-axis side of the shaft member may be sufficient.

  In addition, the second bearing is in contact with the second sphere at three contact points around the shaft around the central axis of the shaft member in the embodiment, but is not limited thereto. It may be in contact with at least four contact points around the center axis of the member.

  In addition, the second bearing is in contact with the second sphere at one axial contact portion on the central axis of the shaft member in the embodiment. However, the second bearing is not limited thereto. It may be in contact with a plurality of on-axis contact portions on the central axis of the member.

  In addition, the second bearing is configured by a flat plate having a recess in the embodiment, but is not limited thereto. For example, the second bearing has the same configuration as the first bearing, that is, the flat plate and one surface of the flat plate. It may be composed of at least three protrusions that are projected from the protrusion.

  In addition, the first bearing and the second bearing are each configured separately from the housing in the above embodiment, but are not limited thereto, and may be formed integrally with the housing, for example. .

  Further, when the support mechanism is viewed from the central axis direction of the shaft member, in the configuration shown in FIG. 3, each shaft contact portion of the first bearing and each shaft contact portion of the second bearing overlap each other. For example, they may be shifted from each other.

Next, specific examples of the centrifugal pump of the present invention will be described.
1. Production and operation of centrifugal pump (Example)
The centrifugal pump shown in FIG. 1 was produced. This centrifugal pump was attached to an external drive means, and the centrifugal pump was operated.
The operating conditions are as follows.

Centrifugal pump rotation speed: 3000 rpm
Operating time: 6 hours Blood passing through centrifugal pump: Pig blood Temperature of blood passing through centrifugal pump: 37 ° C

(Comparative example)
Except that a shaft member and a bearing that are in surface contact were used, the same one as in the example was produced. The operating conditions were the same as in the example.

2. Evaluation The following evaluation was performed on each of the examples and comparative examples.

[2.1] Evaluation of vibration (oscillation) The vibration of each centrifugal pump of the example and the comparative example was measured using a vibration measuring device ("IA-200" manufactured by Keyence Corporation). As a result, it was confirmed that the vibration of the centrifugal pump of the example was reduced by 50% or more than the centrifugal pump of the comparative example. Thereby, in the centrifugal pump of the embodiment, it can be said that the shaft member is reliably prevented from swinging in the horizontal direction.

[2.2] Evaluation of hemolysis Blood passing through the centrifugal pumps of Examples and Comparative Examples was collected every hour, and the collected blood was centrifuged. As a result, it was observed that the blood that passed through the centrifugal pump of the example had less hemolysis with time as compared with the blood that passed through the centrifugal pump of the comparative example. Thereby, in the centrifugal pump of an Example, it can be said that the hemolysis between each of a shaft member and a 1st bearing and a 2nd bearing is suppressed.

DESCRIPTION OF SYMBOLS 1 Centrifugal pump 2 Housing 21 Top plate 22 Bottom plate 221 2nd bearing installation part 23 Side wall 231 Outer peripheral surface (outer peripheral part)
232 Inner peripheral surface 24 Pump chamber 241 Gap 25 Blood inlet 251 Bent part 252 Base part 253 Connection part 254 First bearing installation part 26 Blood outlet 3 Rotating body (impeller)
31 Blood channel 32 Upper surface 33 Outer peripheral surface 34 Permanent magnet 4 Support mechanism 5 Shaft member 51 First sphere 511 Outer surface 52 Second sphere 521 Outer surface 53 Shaft 531 Reduced diameter portion 6 First bearing 61a, 61b, 61c Around the axis contact portion 611 inner surface 62 axial contact portion 621 the lower surface 7 and the second bearing 71a, 71b, 71c axis contact portion 72 on the shaft contact portion 73 upper surface 74 recess D depth H height R _{1, R 2} radius O center Axis Q Blood

Claims (9)

A housing having a hollow body, communicating with the hollow portion, and having a blood inflow port through which blood flows, and a blood outflow port communicating with the hollow portion through which the blood flowing in from the blood inflow port flows out;
A centrifugal force imparting member that is rotatably accommodated in the hollow portion and imparts centrifugal force to blood from the rotation,
A support mechanism that rotatably supports the centrifugal force applying member with respect to the housing;
The support mechanism is composed of a rod-like body that is installed in the center of rotation of the centrifugal force imparting member, and both end portions of the shaft member each form a rotating body around the central axis of the rod-like body, and
A first bearing that rotatably supports one end of the shaft member;
A second bearing that rotatably supports the other end of the shaft member;
The first bearing and the second bearing each have an axial contact portion that contacts at least three points around the central axis with respect to an end portion of the shaft member supported by the bearing, and the central shaft A centrifugal pump comprising an on-axis contact portion that contacts at least one point on the shaft.   The centrifugal pump according to claim 1, wherein one end portion of the shaft member and the other end portion of the shaft member are spheres. At least one of the first bearing and the second bearing is composed of a flat plate and the same number of protrusions as the shaft contact portion formed to protrude from one surface of the flat plate,
The centrifugal pump according to claim 1 or 2, wherein the flat plate functions as the on-axis contact portion, and each of the protrusions functions as the around-axis contact portion.   The centrifugal pump according to claim 3, wherein each of the protrusions has a rounded contact surface in contact with the shaft member. One end of the shaft member and the other end of the shaft member are each a sphere,
The centrifugal pump according to claim 3 or 4, wherein the height of each protrusion is greater than the radius of the sphere. One of the first bearing and the second bearing has a plate shape, and is configured by a flat plate having a recess formed on one surface thereof.
The centrifugal pump according to any one of claims 1 to 5, wherein a bottom surface of the recess functions as the on-axis contact portion, and an inner peripheral surface of the recess functions as a contact portion around each axis.   The centrifugal pump according to claim 6, wherein the concave portion has a triangular shape in plan view. One end of the shaft member and the other end of the shaft member are each a sphere,
The centrifugal pump according to claim 6 or 7, wherein a depth of the concave portion is larger than a radius of the sphere.   The centrifugal pump according to any one of claims 1 to 8, wherein the contact portions around the shaft are arranged at equiangular intervals around the central axis.

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