Pump equipment

Abstract

This pump device (10) comprises: a housing (26) that allows blood to flow in and flow out; and an impeller (14) that is accommodated inside the housing (26), is axially supported by a shaft part (46) provided inside the housing (26), and rotates. The bottom surface (42a) of the housing (26) has a plurality of axial dynamic pressure grooves (102) that generate dynamic pressure in the axial direction. An outer circumferential surface (40a) of the shaft part (46), which is connected to the bottom surface (42a), has a plurality of radial dynamic pressure grooves (112) that generate dynamic pressure in the radial direction. Furthermore, inner ends (104) of the plurality of axial dynamic pressure grooves (102) and lower ends (114) of the plurality of radial dynamic pressure grooves (112) are respectively continuous with each other.

Description

[Technical Field]

[0001] The present invention relates to a pump device for moving a fluid. [Background technology]

[0002] Pump devices are used, for example, as a power source for circulating blood (fluid) in an artificial heart-lung machine that circulates a patient's blood. This type of pump device includes a housing and an impeller housed within the housing, and is configured to draw blood into the housing and expel blood from the housing to the outside by centrifugal force generated by the rotation of the impeller (see, for example, Japanese Patent Application Laid-Open No. 2007-350).

[0003] Furthermore, the pump device disclosed in JP 2007-350 A forms a dynamic pressure bearing between the housing (casing) and the impeller to rotate the impeller without contacting the housing. Specifically, the pump device has axial dynamic pressure grooves (thrust dynamic pressure grooves) for a thrust dynamic pressure bearing on the upper surface of the impeller facing the ceiling surface of the housing, and radial dynamic pressure grooves for a radial dynamic pressure bearing on the outer peripheral surface of the impeller facing the inner peripheral surface of the housing. Summary of the Invention

[0004] By the way, when blood flows between the housing and the impeller, it hits the ends of the dynamic pressure groove or the edges of the extended portion, changing the flow of blood from a direction along the gap between the housing and the impeller to a direction in which the impeller moves away from the housing, thereby forming a dynamic pressure bearing.

[0005] However, viscous fluids tend to stagnate at the ends of these dynamic pressure grooves, and if the fluid is blood, thrombi may form. In particular, in a configuration such as the pump device disclosed in JP 2007-350 A, which has multiple axial dynamic pressure grooves and multiple radial dynamic pressure grooves, there are more locations where the fluid can stagnate, which causes the formation of thrombi, resulting in a decrease in dynamic pressure and further accelerating thrombus formation.

[0006] The present invention relates to the technology of a pump device that forms the above-mentioned hydrodynamic bearing, and aims to provide a pump device that has a simple configuration that can suppress fluid stagnation in hydrodynamic grooves and allow the fluid to flow stably and smoothly.

[0007] In order to achieve the above object, one aspect of the present invention is a pump device comprising: a housing for allowing a fluid to flow in and out; and an impeller accommodated within the housing and rotatably supported on a shaft portion provided within the housing, wherein one surface of the impeller in the rotational axis direction within the housing and a first opposing surface of the impeller opposing the one surface have a plurality of axial dynamic pressure grooves that generate dynamic pressure in the axial direction, and one of an outer peripheral surface of the shaft portion continuous with the one surface and a second opposing surface of the impeller opposing the outer peripheral surface have a plurality of radial dynamic pressure grooves that generate dynamic pressure in the radial direction, wherein the plurality of axial dynamic pressure grooves and the plurality of radial dynamic pressure grooves are provided in the same member of the impeller or the housing, and one end of each of the plurality of axial dynamic pressure grooves and one end of each of the plurality of radial dynamic pressure grooves are continuous with each other.

[0008] The above pump device has a simple configuration that prevents fluid from accumulating in the dynamic pressure grooves, allowing the fluid to flow stably and smoothly. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a pump device according to an embodiment of the present invention; [Figure 2] 2 is a cross-sectional view taken along line II-II in FIG. 1, showing the pump body and the drive unit of the pump device separated from each other. [Figure 3] FIG. 2 is an enlarged cross-sectional view showing the internal configuration of the pump body and the drive device in an attached state. [Figure 4] Fig. 4A is a cross-sectional view taken along line IVA-IVA in Fig. 3. Fig. 4B is a cross-sectional view taken along line IVB-IVB in Fig. 3. [Figure 5]FIG. 3 is an enlarged cross-sectional view showing the locations where axial dynamic pressure grooves and radial dynamic pressure grooves are formed. [Figure 6] FIG. 2 is a partial cross-sectional perspective view showing axial dynamic pressure grooves and radial dynamic pressure grooves provided in a housing. [Figure 7] FIG. 4 is an explanatory diagram showing an enlarged view of a continuous portion between an axial dynamic pressure groove and a radial dynamic pressure groove. [Figure 8] FIG. 3 is a partial plan view showing axial dynamic pressure grooves and radial dynamic pressure grooves. [Figure 9] FIG. 4 is a cross-sectional view showing the flow of blood when the impeller rotates. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to preferred embodiments thereof and the accompanying drawings.

[0011] 1, a pump device 10 according to one embodiment of the present invention is used as a power source for removing blood from a patient's body and sending it into the body in an artificial heart-lung machine 12 that assists (or replaces) the patient's cardiopulmonary function. Pump device 10 has an impeller 14 inside the device, and is configured as a centrifugal pump that moves fluid by centrifugal force generated by the rotation of impeller 14.

[0012] The heart-lung machine 12 connects the blood removal tube 16 and the blood transfer tube 18 to the pump device 10 to form a circulation circuit for circulating blood between the heart and the patient. For example, the distal opening of the blood removal tube 16 is placed in an appropriate vein, the heart (right ventricle, right atrium), etc., while the distal opening of the blood transfer tube 18 is placed in an appropriate artery, the heart (left ventricle, left atrium), etc. The pump device 10 aspirates the patient's blood through the blood removal lumen 16a of the blood removal tube 16 and transfers the blood to the patient through the blood transfer lumen 18a of the blood transfer tube 18. Note that the heart-lung machine 12 may be configured such that, in addition to the pump device 10, a reservoir, an oxygenator, etc. (neither of which are shown) are connected to an intermediate position in the circulation circuit (the blood removal tube 16 or the blood transfer tube 18) to remove foreign matter from the blood removed outside the body and oxygenate it.

[0013] 2, pump device 10 includes pump body 20 that houses impeller 14, drive device 22 that rotates impeller 14, and control unit 24 (Controller) that controls the driving of drive device 22. Housing 26 of pump device 10 is formed from a resin material or the like, and includes a body-side housing 28 that constitutes pump body 20, and a drive-side housing 30 that constitutes drive device 22.

[0014] The main body housing 28 and the drive housing 30 are detachable and, when in use, are assembled together, allowing the driving force of the drive unit 22 to be transmitted to the impeller 14 of the pump main body 20. After use, the pump main body 20 is detached from the drive unit 22 and discarded. In other words, the pump main body 20 is configured as a disposable type that is replaced after each use and thrown away or sterilized. On the other hand, the drive unit 22 is configured as a reusable type, and the next time a new pump main body 20 is used, a new pump main body 20 is attached to operate the impeller 14 of that pump main body 20.

[0015] The main body housing 28 of the pump main body 20 rotatably houses the impeller 14 and has an internal space 32 through which blood flows in and out. The main body housing 28 according to this embodiment is formed by joining an upper housing 28a formed in a generally conical shape and a lower housing 28b formed in a generally cylindrical shape.

[0016] The upper housing 28a has an inflow port 34 in the center of its substantially conical ceiling, for connecting the blood removal tube 16. An inflow channel 34a that communicates with the internal space 32 is provided inside the inflow port 34. The inflow channel 34a communicates with an opening 34a1 (see FIG. 1) at the protruding end of the inflow port 34, and also communicates with an inlet 34a2 provided at the boundary with the internal space 32.

[0017] The lower housing 28b has a substantially cylindrical outer peripheral wall 38 that forms the outside, a cylindrical inner peripheral wall 40 that is provided inside the outer peripheral wall 38, and a bottom 42 that connects the lower ends of the outer peripheral wall 38 and the inner peripheral wall 40 and forms the lower end of the lower housing 28b. The impeller 14 is rotatably disposed between the outer peripheral wall 38 and the inner peripheral wall 40 (around the outer periphery of the inner peripheral wall 40). A chevron portion 44 is connected to the upper end of the inner peripheral wall 40 and closes the inside and upper part of the inner peripheral wall 40. The inner peripheral wall 40 and the chevron portion 44 form a shaft 46 that supports the rotation of the impeller 14 from the inside.

[0018] An outflow port 36 for connecting the blood transfer tube 18 is provided on the upper side surface of the outer peripheral wall 38 of the lower housing 28b. The outflow port 36 protrudes tangentially from the substantially cylindrical outer peripheral wall 38. An outflow channel 36a communicating with the internal space 32 is provided inside the outflow port 36. The outflow channel 36a communicates with an opening 36a1 (see FIG. 1) at the protruding end of the outflow port 36, and also communicates with an outlet 36a2 provided at the boundary with the internal space 32.

[0019] 3, the internal space 32 has an upper space 32a in which a fin portion 60 of the impeller 14 (described later) is disposed, and a lower space 32b in which a driven rotation structure portion 62 of the impeller 14 (described later) is disposed. The upper space 32a is surrounded by the inner surface of the conical portion of the upper housing 28a, the inner surface of the upper cylindrical portion of the lower housing 28b (outer peripheral wall portion 38), and the upper surface of the angled portion 44. The lower space 32b is formed into a cylindrical shape by being surrounded by the outer peripheral wall portion 38, the inner peripheral wall portion 40, and the bottom portion 42, and the upper end of this cylindrical shape communicates with the upper space 32a.

[0020] The shaft portion 46 has an insertion hole 48 formed inside the cylindrical inner circumferential wall portion 40 and the angled portion 44. The insertion hole 48 is open at its lower end, and the drive-side housing 30 is inserted into the insertion hole 48 when the pump body 20 and the drive unit 22 are assembled.

[0021] The angled portion 44 of the shaft 46 is formed in a conical shape that gradually becomes thicker toward the center. A spherical seat 50 that supports the impeller 14 when it is not rotating is provided in the center of the angled portion 44. The seat 50 is made of a metal material and is fixed by a joining method such as adhesive or welding. The center of the seat 50 overlaps an extension line (not shown) of the axis of the inlet port 34 and is located at the axis St of the main body housing 28 (outer peripheral wall portion 38, inner peripheral wall portion 40).

[0022] Additionally, a housing-side repulsion magnet 52 is provided on the lower side of the outer peripheral wall portion 38 of the lower housing 28b. The housing-side repulsion magnet 52 forms a repulsion mechanism 78 in which the housing-side repulsion magnet 52 repels the impeller-side repulsion magnet 76 (described later) provided on the impeller 14.

[0023] The bottom portion 42 of the lower housing 28b extends between the shaft portion 46 and the outer peripheral wall portion 38 in a direction perpendicular to the axis St of the main body housing 28. The bottom portion 42 has a bottom surface 42a (one surface in the rotational axis direction) that faces the impeller 14. The radial length RL (see FIG. 8) of the bottom surface 42a depends on the size of the pump device 10, but is set to, for example, 5 mm to 20 mm.

[0024] 1 to 3, the impeller 14 is formed in a cylindrical shape and is housed in both the upper space 32a and the lower space 32b. The impeller 14 has a fin portion 60 on an upper side and a driven rotation structure portion 62 on a lower side. The inside of the fin portion 60 and the driven rotation structure portion 62 forms a space portion 64 in which the shaft portion 46 is disposed.

[0025] The fin portion 60 includes a conical wall portion 66 connected to the upper end of the driven rotation structure 62, a core portion 68 located at the center of the conical wall portion 66 on the seat portion 50, and multiple protruding wall portions 70 protruding upward from the upper surface of the conical wall portion 66, and generates centrifugal force in the upper space 32a during rotation. A flow passage 70a through which blood flows is formed between adjacent protruding wall portions 70. The upper portion of this flow passage 70a is open. Note that the shape of the fin portion 60 is not limited to this, and for example, a shroud (not shown) may be provided on the upper portion of the protruding wall portions 70 to cover the flow passage 70a.

[0026] The conical wall portion 66 is inclined at a steeper angle than the angled portion 44 of the main body housing 28, and its upper surface is curved in an arch shape. Therefore, a gap (hereinafter referred to as an upper gap 66a) is formed between the angled portion 44 and the conical wall portion 66. The conical wall portion 66 around the core portion 68 is provided with a plurality of washout holes 67 (four in this embodiment) that penetrate the conical wall portion 66. The washout holes 67 connect the upper space 32a above the conical wall portion 66 with the upper gap 66a, allowing blood to flow.

[0027] The core portion 68 is formed in a conical shape that protrudes upward (toward the inlet port 34) beyond the protruding wall portion 70, and its apex substantially coincides with the axis of the inlet port 34 (i.e., the axis St of the main body housing 28) when the impeller 14 is rotating. The lower portion of the core portion 68 is formed flat, and a hemispherical recess 68a is provided in the center thereof into which the seat portion 50 can fit. The recess 68a is in surface contact with the spherical surface of the seat portion 50 when the impeller 14 is not rotating, and rises from the seat portion 50 when the impeller 14 is rotating.

[0028] The structure for supporting the impeller 14 is not limited to the seat 50 and recess 68a as described above, and various other structures are possible. For example, the structure may have a shaft pin (not shown) on one side of the impeller 14 or the housing 26, and a hole into which the shaft pin is inserted on the other side of the impeller 14 or the housing 26.

[0029] Furthermore, the multiple protruding wall portions 70 constituting the fin portion 60 have inner ends that protrude into the respective washout holes 67, while their outer ends extend to near the outer edge of the conical wall portion 66. Each protruding wall portion 70 has a slightly curved, extending arc shape in a plan view along the rotational axis direction of the impeller 14. As a result, the fin portion 60 allows blood that has entered the circulation passages 70a to flow smoothly radially outward when the impeller 14 rotates.

[0030] The driven rotation structure 62 of the impeller 14 is formed in a cylindrical shape that protrudes downward from the outer periphery of the conical wall portion 66 of the fin portion 60. The diameter of the driven rotation structure 62 is not particularly limited, but is preferably set in the range of 20 mm to 50 mm, and is set to 30 mm in this embodiment.

[0031] The driven rotating structure 62 has an outer facing surface 63a facing the outer peripheral wall 38, a bottom facing surface 63b (first facing surface) facing the bottom 42, and a shaft facing surface 63c (second facing surface) facing the shaft 46. Inside the driven rotating structure 62, a driven magnet 74 and an impeller-side repulsive magnet 76 are installed.

[0032] The driven magnet 74 is embedded in the driven rotating structure 62 on the upper side (fin portion 60) and radially inward (shaft-facing surface 63c). As shown in FIG. 4A, the driven magnet 74 is configured as a driven-side multi-pole magnetized ring magnet 75 that orbits at a constant radius R1 around the axis Si of the impeller 14. The driven-side multi-pole magnetized ring magnet 75 is a magnet that is magnetized so that multiple N poles and S poles are arranged alternately in the circumferential direction. Note that in FIG. 4A, the driven-side multi-pole magnetized ring magnet 75 has six polarities (i.e., three opposing poles), but the number of polarities is of course not limited to this.

[0033] Examples of materials that can be used to form the driven magnet 74 include hard magnetic materials such as alnico, ferrite, neodymium, etc. The driven magnet 74 is not limited to being formed as a multi-pole magnetized ring, and may be formed into a ring shape by arranging multiple arc-shaped magnets with opposite poles (north and south poles) in the circumferential direction.

[0034] 3 and 4B, the impeller-side repulsive magnet 76 is embedded in the lower portion of the driven rotating structure 62, and toward the radially outer side (external facing surface 63a). The driven magnet 74 and the impeller-side repulsive magnet 76 are spaced apart from each other in the vertical direction within the driven rotating structure 62 so as to suppress the influence of their mutual magnetic fields.

[0035] The impeller-side repulsive magnet 76 is configured as an impeller-side inner and outer periphery monopole magnetized ring magnet 77 that revolves around the axis Si of the impeller 14 at a radius R2 that is longer than the radius R1 of the driven magnet 74. The impeller-side inner and outer periphery monopole magnetized ring magnet 77 is a magnet that has a first polarity (S pole in FIG. 3) over the entire circumference of its outer periphery, and is magnetized to have a second polarity (N pole in FIG. 3) opposite to the first polarity over the entire circumference of its inner periphery. The material that constitutes the impeller-side repulsive magnet 76 is not particularly limited, and the materials listed for the driven magnet 74 can be used.

[0036] As described above, the housing-side repulsion magnets 52 are provided inside the outer peripheral wall portion 38 of the lower housing 28b. The housing-side repulsion magnets 52 are disposed radially outward and slightly above (at a position offset in a direction approaching the inlet 34a2) the impeller-side repulsion magnets 76. In other words, the lower ends of the housing-side repulsion magnets 52 are positioned above the lower ends of the impeller-side repulsion magnets 76.

[0037] The housing-side repulsion magnet 52 is configured as a housing-side inner and outer periphery monopole magnetized ring magnet 53 that circles at a constant radius R3 at the position farthest from the axis St of the main body housing 28. The housing-side inner and outer periphery monopole magnetized ring magnet 53 is a ring body that is magnetized so that it has a first polarity (N pole in FIG. 3) around the entire circumference of its outer periphery and a second polarity (S pole in FIG. 3) opposite to the first polarity around the entire circumference of its inner periphery. The material that makes up this housing-side repulsion magnet 52 is not particularly limited, and the materials listed for the driven magnet 74 can be used.

[0038] The repulsion mechanism 78 (housing-side repulsion magnets 52, impeller-side repulsion magnets 76) generates a repulsive force (a repulsive force) that pushes the impeller-side repulsion magnets 76 radially inward and downward relative to the housing-side repulsion magnets 52. This repulsion mechanism 78 presses the impeller 14 in a direction away from the inlet 34a2 and also presses it radially inward from the entire circumferential direction.

[0039] 2 and 3, the drive device 22 of the pump device 10 includes a drive-side housing 30 and a motor mechanism 80 housed within the drive-side housing 30. The drive-side housing 30 has an annular mounting groove 82 for mounting the pump body 20 (main body-side housing 28), and also has a central protrusion 84 located radially inward of the mounting groove 82 that is inserted into the insertion hole 48 of the main body-side housing 28.

[0040] The shaft portion 46 (insertion hole 48) and bottom portion 42 of the pump body 20, and the mounting groove 82 and central protrusion 84 of the drive unit 22 constitute an engagement structure 86 between the pump body 20 and the drive unit 22 that detachably engages them. Of course, the engagement structure 86 between the pump body 20 and the drive unit 22 is not particularly limited and various methods can be used.

[0041] A motor main body 80a of the motor mechanism 80 is provided inside the drive-side housing 30, and the motor main body 80a rotates a rotary shaft 80b at an appropriate rotational speed under the control of the control unit 24. A rotor 88 is provided on the protruding portion of the rotary shaft 80b, and is inserted into a protruding space in a central protrusion 84. When the pump main body 20 and the drive unit 22 are attached, the axis Si of the impeller 14 and the axis Ss of the rotary shaft 80b and the rotor 88 are aligned with each other.

[0042] In a side cross-sectional view, the rotor 88 has cutouts at the top and bottom of the outer peripheral surface on the radially outer side, and these cutouts hold an annular drive magnet 92. Therefore, the drive magnet 92 rotates integrally with the rotor 88.

[0043] 4A, the drive magnet 92 is configured as a drive-side multi-pole magnetized ring magnet 93 that orbits around the axis Ss of the rotating body 88 at a radius R4 that is shorter than the radius R1 of the driven magnet 74. Similar to the driven-side multi-pole magnetized ring magnet 75, the drive-side multi-pole magnetized ring magnet 93 is a magnet that is magnetized so that multiple (six) polarities (N poles, S poles) are arranged alternately in the circumferential direction.

[0044] The axial length of the drive magnet 92 (thickness parallel to the axis Ss) is set to be approximately the same as the axial length of the driven magnet 74. When the pump body 20 and the drive device 22 are mounted, the drive magnet 92 is disposed inside the driven magnet 74 and facing the same height as the driven magnet 74, thereby forming a magnetic coupling mechanism 94 that attracts the drive magnet 92 and the driven magnet 74. For example, the attractive force of the magnetic coupling mechanism 94 is set to be smaller than the repulsive force of the repulsive mechanism 78 when the axis Si of the impeller 14 is aligned with the axis St of the main body housing 28.

[0045] The material constituting the drive magnet 92 may be appropriately selected from the materials listed for the driven magnet 74. Furthermore, the drive magnet 92 is not limited to being constituted as a multi-pole magnetized ring, but may also be formed into a ring shape by arranging multiple arc-shaped magnets having opposite poles (north and south poles) in the circumferential direction.

[0046] 3, in the pump device 10 according to this embodiment, an axial dynamic pressure bearing 100 and a radial dynamic pressure bearing 110 are formed between the impeller 14 and the housing 26 as the impeller 14 rotates. The axial dynamic pressure bearing 100 generates dynamic pressure in the axial direction along the direction of the rotational axis of the impeller 14 (axis center Si) as the impeller 14 rotates, thereby separating (floating) the impeller 14 from the housing 26. The radial dynamic pressure bearing 110 generates dynamic pressure in the radial direction perpendicular to the direction of the rotational axis of the impeller 14 as the impeller 14 rotates, thereby separating (leaving) the impeller 14 from (non-contacting) the housing 26.

[0047] 5, the axial dynamic pressure bearing 100 is formed between the bottom surface 42a of the bottom portion 42 and the bottom opposing surface 63b of the driven rotating structure 62. For example, when the impeller 14 is in a non-rotating state (when the impeller 14 is in contact with the seat portion 50), the distance I1 between the bottom surface 42a and the bottom opposing surface 63b is preferably set in the range of 0 mm to 0.01 mm.

[0048] Furthermore, the axial dynamic pressure bearing 100 is formed by a plurality of axial dynamic pressure grooves 102 provided in the bottom surface 42a of the bottom portion 42 when the impeller 14 rotates. As shown in Fig. 6, the axial dynamic pressure grooves 102 are arranged at equal intervals from one another to form an annular groove group around the circumferential direction of the bottom surface 42a. In other words, blood flowing radially inward and circumferentially between the bottom surface 42a and the bottom opposing surface 63b is directed upward (toward the inlet 34a2) by the plurality of axial dynamic pressure grooves 102, thereby generating dynamic pressure in the axial direction. The number of axial dynamic pressure grooves 102 formed is not particularly limited, and is set to 12 in this embodiment.

[0049] Each axial dynamic pressure groove 102 is formed in an arc shape that extends radially and curves circumferentially in a plan view along the rotation axis direction. The direction of the arc of each axial dynamic pressure groove 102 is set to the rotational direction (counterclockwise) of the impeller 14. Each axial dynamic pressure groove 102 extends over a range on the bottom surface 42a from the boundary with the shaft portion 46 to the boundary with the outer peripheral wall portion 38, in other words, over the entire radial direction of the bottom surface 42a.

[0050] 6 and 7, each inner end 104 (one end) of each axial dynamic pressure groove 102 is located at the boundary between the bottom surface 42a and the outer peripheral surface 40a of the shaft portion 46, and is continuous with a lower end 114 of each radial dynamic pressure groove 112, which will be described later. In detail, the inner end 104 of each axial dynamic pressure groove 102 has an arc-shaped outer edge 103a that is continuous with a first edge 113a of each radial dynamic pressure groove 112, and an arc-shaped inner edge 103b that is continuous with a second edge 113b of each radial dynamic pressure groove 112. The arc-shaped outer edge 103a is curved from the first edge 113a via an R-shaped rounded corner 103a1 toward the arc-shaped inner edge 103b at a predetermined inclination angle and a predetermined curvature. The arcuate inner edge 103b is curved from the second edge 113b via a rounded corner 103b1 at the same inclination angle and curvature as the arcuate outer edge 103a.

[0051] As a result, the arc-shaped outer edge 103a and the arc-shaped inner edge 103b extend close to each other (narrow groove width) near the shaft portion 46, but gradually move apart (wider groove width) toward the radially outer side of the bottom surface 42a. At the boundary where the bottom surface 42a and the inner circumferential surface 38a of the outer circumferential wall portion 38 are connected (outer end 106 of each axial dynamic pressure groove 102), the arc-shaped outer edge 103a smoothly connects to the inner circumferential surface 38a, while the arc-shaped inner edge 103b connects to the inner circumferential surface 38a via an R-shaped folded portion 103b2.

[0052] 8, the inclination angle θ of each axial dynamic pressure groove 102 (arcuate outer edge 103a, arcuate inner edge 103b) with respect to the tangent line T at the point where the inner end 104 contacts the shaft portion 46 is preferably set in the range of 5° to 30°, for example. This allows each axial dynamic pressure groove 102 to extend long on the bottom surface 42a.

[0053] Furthermore, the longitudinal length AL (arc length: shown in FIG. 8 as the distance between the inner end 104 and the outer end 106 for convenience) of each axial dynamic pressure groove 102 is set to be sufficiently longer than the radial length RL of the bottom surface 42a of the bottom portion 42. For example, it is preferable that the longitudinal length AL of each axial dynamic pressure groove 102 be set to be at least twice the radial length RL of the bottom surface 42a. By setting the longitudinal length of each axial dynamic pressure groove 102 to be long in this way, it becomes possible to make it easier for the flowing blood to come into contact with each axial dynamic pressure groove 102 (arc outer edge 103a).

[0054] 5, the groove bottom 102a of each axial dynamic pressure groove 102 is formed flat and extends at a constant depth from the bottom surface 42a. The depth of each axial dynamic pressure groove 102 is sufficiently short (shallow) relative to the groove width. The depth of each axial dynamic pressure groove 102 may be set according to the target dynamic pressure in the axial direction, and may be formed, for example, to be the same as the depth of each radial dynamic pressure groove 112 or deeper than the depth of the radial dynamic pressure groove 112.

[0055] On the other hand, the radial dynamic pressure bearing 110 is formed between the outer peripheral surface 40a of the shaft portion 46 (inner peripheral wall portion 40) and the shaft portion facing surface 63c of the driven rotation structure portion 62. A distance I2 between the outer peripheral surface 40a of the inner peripheral wall portion 40 and the shaft portion facing surface 63c is shorter than a distance I3 between the inner peripheral surface 38a of the outer peripheral wall portion 38 and the outer facing surface 63a of the impeller 14. For example, the specific dimension of the distance I2 is preferably set in the range of 0.01 mm to 0.1 mm.

[0056] 6 to 8, the radial dynamic pressure bearing 110 is generated by a plurality of radial dynamic pressure grooves 112 provided on the outer peripheral surface 40a of the shaft portion 46 (inner peripheral wall portion 40) when the impeller 14 rotates. In this embodiment, the number of radial dynamic pressure grooves 112 formed is the same as the number of axial dynamic pressure grooves 102 formed, and one end (lower end 114) of each radial dynamic pressure groove 112 is continuous with one end (inner end 104) of each axial dynamic pressure groove 102.

[0057] The radial dynamic pressure grooves 112 extend linearly in the up-down direction (height direction) of the shaft portion 46 and are arranged at equal intervals along the circumferential direction of the outer peripheral surface 40a. That is, the radial dynamic pressure grooves 112 extend parallel to the direction of the rotational axis (axis center Si) of the impeller 14 and the axis center St of the shaft portion 46 (main body housing 28). Note that the radial dynamic pressure grooves 112 are not limited to extending linearly, and may extend spirally on the outer peripheral surface 40a.

[0058] Each radial dynamic pressure groove 112 has an arc-shaped or flat groove bottom 112a that follows the outer peripheral surface 40a of the inner peripheral wall portion 40, and a first edge 113a and a second edge 113b that are provided on both circumferential sides of the groove bottom 112a. The groove width W of each radial dynamic pressure groove 112 (groove bottom 112a) may be designed as desired depending on the size of the shaft portion 46, the number of radial dynamic pressure grooves 112 formed, and the like. For example, the groove width W may be set to be equal to or greater than the distance D between adjacent radial dynamic pressure grooves 112. A specific dimension of the groove width W is preferably set in the range of 2 mm to 5 mm. The depth of each radial dynamic pressure groove 112 relative to the outer peripheral surface 40a of the shaft portion 46 is also not particularly limited, and may be set in the range of 0.05 mm to 0.2 mm, for example.

[0059] Furthermore, the outer peripheral surface 40a and the shaft portion opposing surface 63c are parallel to the axis St of the shaft portion 46 and the axis Si of the driven rotating structure portion 62, and each radial dynamic pressure groove 112 is formed over the entire axial length of the inner peripheral wall portion 40 of the shaft portion 46. That is, the lower end 114 (one end) of each radial dynamic pressure groove 112 is located at the boundary between the inner peripheral wall portion 40 and the bottom portion 42, and is continuous with the inner end 104 of each axial dynamic pressure groove 102 as described above.

[0060] The boundary between the bottom surface 42a and the outer peripheral surface 40a of the housing 26 is smoothly connected (in a rounded shape). The groove bottoms 112a of the lower ends 114 of the adjacent radial dynamic pressure grooves 112 and the groove bottoms 102a of the inner ends 104 of the adjacent axial dynamic pressure grooves 102 are also connected in a rounded shape. The first edge 113a connected to the arc-shaped outer edge 103a and the second edge 113b connected to the arc-shaped inner edge 103b extend linearly as described above.

[0061] Additionally, the upper end 116 (other end) of each radial dynamic pressure groove 112 is located at the boundary between the inner circumferential wall portion 40 and the angled portion 44, and penetrates (opens) upward toward the upper gap 66a. The extension length of each radial dynamic pressure groove 112 (outer circumferential surface 40a) is set to be in the range of 10 mm to 100 mm, for example. This allows the radial dynamic pressure bearing 110 to be formed over a long range in the direction of the rotational axis of the impeller 14, stabilizing the rotational posture of the impeller 14.

[0062] Returning to Figure 2, the control unit 24 (Controller) of the pump device 10 is configured by a well-known computer having an input / output interface, memory, and processor (not shown), and controls the driving of the motor mechanism 80. A monitor, speaker, operation buttons, etc. (not shown) are provided on the exterior of the control unit 24, and a user such as a doctor or nurse operates the operation buttons to set the driving details of the pump device 10. Based on the user's setting information, the control unit 24 controls the supply of battery power to rotate the rotor 88 within a range of 0 to 10,000 rpm, for example.

[0063] The pump device 10 according to this embodiment is basically configured as described above, and its operation will be described below.

[0064] An artificial heart-lung machine 12 including the pump device 10 is configured for a patient to have their cardiopulmonary function assisted. When configuring the artificial heart-lung machine 12, the user connects the blood removal tube 16 to the inflow port 34 of the pump body 20 and the blood delivery tube 18 to the outflow port 36 of the pump body 20. The user then attaches the pump body 20 to the drive unit 22, thereby putting the pump device 10 into a usable state.

[0065] In the installed state, as shown in Fig. 3, the driven magnet 74 and the drive magnet 92 are positioned at approximately the same height. The driven magnet 74 and the drive magnet 92 that are adjacent in the radial direction generate a magnetic coupling force between their opposite polarities, thereby forming a magnetic coupling mechanism 94. As a result, the control unit 24 of the pump device 10 rotates the motor mechanism 80 based on the control content set by the user, thereby causing the impeller 14 to rotate together.

[0066] The impeller 14 generates centrifugal force during rotation, causing blood to flow. As shown in FIG. 9 , when the impeller 14 rotates, blood that flows into the internal space 32 from the inlet channel 34a flows radially outward due to the rotation of the fin portion 60. The blood then flows from the radially outer side of the upper space 32a into the lower space 32b. This blood flows downward (toward the bottom portion 42) between the outer circumferential wall portion 38 and the driven rotating structure portion 62, and then flows radially inward between the bottom portion 42 and the driven rotating structure portion 62. The blood then flows upward (toward the fin portion 60) between the shaft portion 46 and the driven rotating structure portion 62, and returns to the upper space 32a through the upper gap 66a and the multiple washout holes 67.

[0067] Here, when the impeller 14 rotates, the pump device 10 forms an axial dynamic pressure bearing 100 between the bottom portion 42 and the driven rotation structure 62, and a radial dynamic pressure bearing 110 between the shaft portion 46 and the driven rotation structure 62. Specifically, the impeller 14 rotates counterclockwise in FIG. 1. The multiple axial dynamic pressure grooves 102 provided in the bottom surface 42a extend counterclockwise from the outer end 106 to the inner end 104, causing blood to flow radially inward along the rotation direction of the impeller 14. At this time, the outer end 106 of each axial dynamic pressure groove 102 extends to the inner circumferential surface 38a of the outer circumferential wall portion 38, allowing blood to smoothly flow into the axial dynamic pressure grooves 102. Each axial dynamic pressure groove 102 generates a dynamic pressure that directs blood upward (toward the inlet 34a2) along the extension direction of the arc-shaped outer edge 103a. The axial dynamic pressure bearing 100, which is formed by this dynamic pressure, separates the impeller 14 from the bottom portion 42 as the impeller 14 rotates.

[0068] However, the housing-side repulsive magnets 52 and the impeller-side repulsive magnets 76 of the pump body 20 mutually repel each other, constituting a repulsive mechanism 78. This repulsive mechanism 78 presses the impeller 14 in a direction away from the inlet 34a2, so even if the impeller 14 is raised by the axial dynamic pressure bearing 100, it will rotate stably at a height position that is appropriately spaced from the bottom 42 (see distance I1' in FIG. 9: distance I1'>distance I1).

[0069] Then, the blood that has moved to the inner ends 104 of each axial dynamic pressure groove 102 flows smoothly to each radial dynamic pressure groove 112 that is continuous with each axial dynamic pressure groove 102. In other words, because the inner ends 104 and the lower ends 114 are continuous (communicating), blood is prevented from accumulating at the ends of each axial dynamic pressure groove 102, and can flow to the radial dynamic pressure grooves 112.

[0070] The blood that has moved to the lower ends 114 of the radial dynamic pressure grooves 112 flows upward (toward the inlet 34a2) due to the radial dynamic pressure grooves 112, while also flowing in the rotational direction (counterclockwise) of the impeller 14. The blood generates dynamic pressure at the first edges 113a of the radial dynamic pressure grooves 112 that flows radially outward (moving the driven rotating structure 62 apart in the radial direction). This allows the pump device 10 to rotate the impeller 14 without contacting it relative to the shaft 46. As a result, the pump device 10 can align the axis Si of the impeller 14 with the axis St of the main body housing 28, and can stably maintain the rotational posture of the impeller 14.

[0071] Furthermore, since the upper ends 116 of the radial dynamic pressure grooves 112 are open, the blood that has moved to each radial dynamic pressure groove 112 flows out smoothly above the shaft portion 46 (inner circumferential wall portion 40). In other words, blood is prevented from accumulating in each radial dynamic pressure groove 112 as well.

[0072] Because the impeller 14 is floating above the seat 50, the blood that has moved to the upper gap 66a moves into the upper space 32a through the washout holes 67 while circulating inside the conical wall portion 66. Then, in the upper space 32a, the blood receives the centrifugal force of the impeller 14 and flows into the outlet 36a2, and is sent to the blood transfer tube 18 through the outlet port 36.

[0073] The present invention is not limited to the above-described embodiment, and various modifications are possible within the spirit and scope of the invention. For example, the pump device 10 is not limited to a device for circulating blood, and may be modified appropriately to circulate other fluids, such as cellular fluids or medicinal fluids.

[0074] Furthermore, the pump device 10 may have a different number of axial dynamic pressure grooves 102 than the number of radial dynamic pressure grooves 112. In other words, the pump device 10 is not limited to a configuration in which all of the axial dynamic pressure grooves 102 and radial dynamic pressure grooves 112 are continuous, as long as at least one axial dynamic pressure groove 102 and one radial dynamic pressure groove 112 are continuous.

[0075] For example, the pump device 10 may be configured to have a plurality of radial dynamic pressure grooves 112 and a plurality of axial dynamic pressure grooves 102 on the impeller 14 side. That is, the pump device 10 may be configured to have each axial dynamic pressure groove 102 on the bottom-facing surface 63b of the driven rotating structure 62, and each radial dynamic pressure groove 112 on the shaft-facing surface 63c of the driven rotating structure 62. Even in this case, the same effect as above can be obtained as long as the inner ends 104 of the axial dynamic pressure grooves 102 and the lower ends 114 of the radial dynamic pressure grooves 112 are continuous. Furthermore, the pump device 10 may be configured to have each axial dynamic pressure groove 102 and each radial dynamic pressure groove 112 on both the impeller 14 side and the main body housing 28 side.

[0076] Furthermore, the axial dynamic pressure grooves 102 are not limited to being formed on the bottom surface 42a, which is one surface in the rotational axis direction of the impeller 14. For example, in a configuration in which the impeller 14 has a shroud, the pump device 10 may have the axial dynamic pressure grooves 102 on at least one of the shroud and the ceiling surface of the housing 26 facing the shroud.

[0077] Furthermore, for example, the pump device 10 may be configured such that the inner circumferential wall portion 40 of the shaft portion 46 is formed at a slight inclination with respect to the axis Si (the direction of the rotational axis of the impeller 14), so that each radial dynamic pressure groove 112 is also inclined with respect to the axis Si. This makes it possible to widen the gap I2 between the outer circumferential surface 40a of the inner circumferential wall portion 40 and the shaft portion-opposing surface 63c of the driven rotating structure portion 62 when the impeller 14 floats during rotation. The pump device 10 can suppress the shear force that occurs when the gap I2 is narrow, thereby reducing the occurrence of hemolysis.

[0078] The technical ideas and effects that can be understood from the above-described embodiments will be described below.

[0079] One aspect of the present invention is a pump device 10 including a housing 26 for allowing a fluid to flow in and out, and an impeller 14 accommodated in the housing 26 and supported by a shaft 46 provided in the housing 26 for rotation, wherein the impeller 14 has a plurality of axial dynamic pressure grooves 102 on one side (bottom surface 42a) of the housing 26 in the rotation axis direction, and a first opposing surface (bottom opposing surface 63b) of the impeller 14 opposing the one side, and the impeller 14 has a plurality of axial dynamic pressure grooves 102 on the one side Either the outer peripheral surface 40a of the connected shaft portion 46 or the second opposing surface (shaft portion opposing surface 63c) of the impeller 14 opposing the outer peripheral surface 40a has a plurality of radial dynamic pressure grooves 112 that generate dynamic pressure in the radial direction, and the plurality of axial dynamic pressure grooves 102 and the plurality of radial dynamic pressure grooves 112 are provided in the same member of the impeller 14 or the housing 26, and one end (inner end 104) of each of the plurality of axial dynamic pressure grooves 102 and one end (lower end 114) of each of the plurality of radial dynamic pressure grooves 112 are continuous with each other.

[0080] As described above, in the pump device 10, one end (inner end 104) of each axial dynamic pressure groove 102 and one end (lower end 114) of each radial dynamic pressure groove 112 are continuous with each other, thereby enabling the fluid to flow stably and smoothly between each axial dynamic pressure groove 102 and each radial dynamic pressure groove 112. That is, the pump device 10 can prevent the fluid from stagnating at one end of the dynamic pressure groove. Particularly when the fluid is blood, the blood flows smoothly without stagnating at the boundary between each axial dynamic pressure groove 102 and each radial dynamic pressure groove 112, thereby preventing the formation of thrombi due to stagnation. Furthermore, in the pump device 10, the formation of a two-way dynamic pressure bearing further stabilizes the rotational position of the impeller 14, thereby significantly reducing the occurrence of thrombi and hemolysis due to tilting of the rotational position of the impeller 14.

[0081] Additionally, the plurality of axial dynamic pressure grooves 102 and the plurality of radial dynamic pressure grooves 112 are formed in the housing 26. As a result, in the pump device 10, dynamic pressure is generated in the impeller 14 from the housing 26, and the rotational posture of the impeller 14 can be further stabilized.

[0082] Furthermore, the plurality of radial dynamic pressure grooves 112 are formed in the same number as the plurality of axial dynamic pressure grooves 102, and are connected to one end (inner end 104) of each of the axial dynamic pressure grooves 102. This allows the pump device 10 to more uniformly flow the fluid between one surface (bottom surface 42a) and the first opposing surface (bottom opposing surface 63b) and between the outer circumferential surface 40a and the second opposing surface (shaft opposing surface 63c), thereby enabling the impeller 14 to rotate stably.

[0083] Furthermore, the plurality of radial dynamic pressure grooves 112 extend linearly along the direction of the rotational axis of the impeller 14. This allows the pump device 10 to make the fluid flow along the radial dynamic pressure grooves 112 even more smoothly.

[0084] Furthermore, the multiple radial dynamic pressure grooves 112 extend to the edge of the outer peripheral surface 40a or the edge of the second opposing surface (shaft portion opposing surface 63c). As a result, the radial dynamic pressure grooves 112 can form a radial dynamic pressure bearing 110 that is long in the direction of the rotation axis of the impeller 14 when the impeller 14 rotates, making it possible to better maintain a non-contact state of the impeller 14 with respect to the shaft portion 46.

[0085] Furthermore, the longitudinal length of the multiple axial dynamic pressure grooves 102 is at least twice the radial length of one surface (bottom surface 42a). This enables the axial dynamic pressure grooves 102 to generate axial dynamic pressure over a sufficiently long range, and the housing 26 and impeller 14 can be stably kept out of contact with each other.

[0086] The inclination angle θ of the plurality of axial dynamic pressure grooves 102 with respect to the tangent line T of the shaft portion 46 is set in the range of 5° to 30°. This allows the pump device 10 to ensure the longitudinal length of the axial dynamic pressure grooves 102 while appropriately generating dynamic pressure accompanying the rotation of the impeller 14.

[0087] Furthermore, the impeller 14 has an impeller-side repulsive magnet 76, while the housing 26 has a housing-side repulsive magnet 52 that generates a repulsive force between the impeller-side repulsive magnet 76 and the housing 26 in the direction opposite to the dynamic pressure in the axial direction. Due to the repulsive force between the impeller-side repulsive magnet 76 and the housing-side repulsive magnet 52, the pump device 10 can stably rotate the impeller 14 while effectively preventing the impeller 14 from moving significantly away from the housing 26 due to the dynamic pressure in the axial direction.

[0088] Furthermore, the multiple axial dynamic pressure grooves 102 are formed in an arc shape when viewed from above along the direction of the rotation axis of the impeller 14, and the arc outer edge 103a and arc inner edge 103b at one end of the multiple axial dynamic pressure grooves 102 have rounded corners 103a1, 103b1 at locations continuous with the edges (first edge 113a, second edge 113b) of the multiple radial dynamic pressure grooves 112. This allows the pump device 10 to more effectively prevent fluid from accumulating between the multiple axial dynamic pressure grooves 102 and the multiple radial dynamic pressure grooves 112 (axial dynamic pressure groove ends).

Claims

1. a housing through which fluid flows in and out; an impeller accommodated in the housing and rotatably supported on a shaft portion provided in the housing, a plurality of axial dynamic pressure grooves that generate dynamic pressure in an axial direction are provided on one of one surface of the impeller in the rotational axis direction within the housing and a first opposing surface of the impeller that faces the one surface; a plurality of radial dynamic pressure grooves that generate dynamic pressure in a radial direction are provided on either an outer peripheral surface of the shaft portion that is continuous with the one surface or a second opposing surface of the impeller that faces the outer peripheral surface, the plurality of axial dynamic pressure grooves and the plurality of radial dynamic pressure grooves are provided in the same member of the impeller or the housing, one end of each of the plurality of axial dynamic pressure grooves and one end of each of the plurality of radial dynamic pressure grooves are continuous with each other, Each of the plurality of radial dynamic pressure grooves extends linearly in the height direction of the shaft portion so as to extend parallel to the axis of the shaft portion, and is arranged at equal intervals along the circumferential direction of the outer circumferential surface of the shaft portion. Pumping equipment.

2. 2. The pump device according to claim 1, The plurality of axial dynamic pressure grooves and the plurality of radial dynamic pressure grooves are formed in the housing. Pumping equipment.

3. 3. The pump device according to claim 1, The plurality of radial dynamic pressure grooves are formed in the same number as the plurality of axial dynamic pressure grooves, and are connected to one end of each of the axial dynamic pressure grooves. Pumping equipment.

4. The pump device according to any one of claims 1 to 3, The plurality of radial dynamic pressure grooves extend to an edge of the outer circumferential surface or an edge of the second opposing surface. Pumping equipment.

5. The pump device according to any one of claims 1 to 4, The longitudinal length of the plurality of axial dynamic pressure grooves is at least twice the radial length of the one surface. Pumping equipment.

6. 6. The pump device according to claim 5, The inclination angle of the plurality of axial dynamic pressure grooves with respect to the tangent line of the shaft portion is set in the range of 5° to 30°. Pumping equipment.

7. The pump device according to any one of claims 1 to 6, The impeller has an impeller-side repulsive magnet, The housing has a housing-side repulsion magnet that generates a repulsive force between the housing-side repulsion magnet and the impeller-side repulsion magnet in a direction opposite to the dynamic pressure in the axial direction. Pumping equipment.

8. The pump device according to any one of claims 1 to 7, the plurality of axial dynamic pressure grooves are formed in an arc shape in a plan view along the rotational axis direction of the impeller, The arcuate outer edges and arcuate inner edges at one end of the plurality of axial dynamic pressure grooves have rounded corners at locations that are continuous with the edges of the plurality of radial dynamic pressure grooves. Pumping equipment.

9. a housing through which fluid flows in and out; an impeller accommodated in the housing and rotatably supported on a shaft portion provided in the housing, a plurality of axial dynamic pressure grooves that generate dynamic pressure in an axial direction are provided on one of one surface of the impeller in the rotational axis direction within the housing and a first opposing surface of the impeller that faces the one surface; a plurality of radial dynamic pressure grooves that generate dynamic pressure in the radial direction are provided on an outer peripheral surface of the shaft portion that is connected to the one surface, the plurality of axial dynamic pressure grooves and the plurality of radial dynamic pressure grooves are provided in the same member of the impeller or the housing, one end of each of the plurality of axial dynamic pressure grooves and one end of each of the plurality of radial dynamic pressure grooves are continuous with each other, The shaft portion is an inner peripheral wall portion having the outer peripheral surface of the shaft portion; a mountain-shaped portion connected to an end of the inner circumferential wall portion opposite to the one surface of the housing; and each of the plurality of radial dynamic pressure grooves extends in a height direction of the shaft portion; An end of each of the plurality of radial dynamic pressure grooves opposite to the one surface is located at the boundary between the inner circumferential wall portion and the mountain-shaped portion, and is open toward the opposite side to the one surface. Pumping equipment.

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