JP6970574B2 - Pump device - Google Patents

Description

The present invention relates to a pump device for flowing a fluid.

The pump device is used as a blood circulation device for flowing blood (fluid) in an artificial heart-lung machine. For example, the pump device disclosed in Patent Document 1 rotates an impeller (impeller) in a housing, draws blood into the housing by centrifugal force accompanying the rotation, and discharges blood from the housing.

In particular, the pump device described in Patent Document 1 includes a dynamic pressure bearing that rotates the impeller in a non-contact manner relative to the housing. For example, the dynamic pressure bearing disclosed in Patent Document 1 is composed of a plurality of spiral grooves provided on a surface facing the housing in the thrust direction of the impeller, and utilizes the dynamic pressure when the fluid flows to the housing. The impeller is separated from the impeller and rotated. This reduces mechanical wear on the housing and impeller, as well as the occurrence of thrombi and hemolysis.

Japanese Unexamined Patent Publication No. 2013-212218

By the way, in the groove-shaped dynamic pressure bearing as described above, it is desirable that the dynamic pressure applied between the impeller and the housing is evenly distributed. If the distribution of the dynamic pressure is uneven, the impeller becomes unstable in its rotational posture and is more likely to come into contact with the housing. Therefore, it is conceivable to equalize the dynamic pressure by using a dynamic pressure bearing in which a large number of groove portions having a sufficiently narrow groove width are arranged. However, when blood is flowed using a pump device, if the groove width of the groove is narrow, the blood is likely to be clogged, which causes inconveniences such as a decrease in dynamic pressure.

The present invention has been made to solve the above-mentioned problems, and a pump capable of equalizing the dynamic pressure between the impeller and the housing and rotating the impeller more stably by a simple configuration. The purpose is to provide the device.

In order to achieve the above object, the pump device according to the present invention includes a housing for inflowing and outflowing fluid and an impeller rotatably housed in the housing , and the impeller in the housing is paired with the impeller. An annular dynamic pressure bearing is provided on the facing surface to generate a dynamic pressure at which the impeller is not in contact with the housing as the impeller rotates, and the dynamic pressure bearing is provided from the inside to the outside. The extending first groove portion and the second groove portion are alternately arranged in the circumferential direction around the rotation axis of the impeller, and the length of the second groove portion in the extending direction is the length of the first groove portion. the extending direction of the rather short than a length, the radially outer side of the first groove, continuous with the edge portion of the hydrodynamic bearing, the second groove radially outer and said rotation axis side of the said dynamic pressure bearing The edge portion of the first groove portion on the rotation axis side and the edge portion of the second groove portion on the rotation axis side are radially outside the inner peripheral surface of the impeller without being connected to the edge portion. It is characterized by.

According to the above, the pump device constitutes a dynamic pressure bearing by alternately arranging the first groove portion and the second groove portion whose length in the extending direction is shorter than that of the first groove portion in the circumferential direction. The dynamic pressure between the impeller and the housing can be equalized. That is, the second groove fills the portion where the gap is wide between the first grooves, generates an appropriate dynamic pressure, and reduces the portion where the dynamic pressure becomes sparse. Therefore, the dynamic pressure bearing makes it possible to stably rotate the impeller in a non-contact state by uniform dynamic pressure, suppress the generation of hemolysis and thrombus, and allow blood to flow smoothly. Further, in the pump device, since the radial outer side of the first groove portion is connected to the edge portion of the dynamic pressure bearing, the fluid flowing into the internal space can enter the first groove portion from the radial outer side. As a result, the first groove portion can smoothly obtain the dynamic pressure from the fluid.

Further, it is preferable that the second groove portion is arranged between the outer portions of the first groove portion.

In the pump device, since the second groove portion is arranged between the outer portions of the first groove portion, it is possible to increase the dynamic pressure on the outer side in the radial direction in which the dynamic pressure tends to be low in the annular dynamic pressure bearing.

Further, the length of the second groove portion in the extending direction is preferably 0.3 to 0.7 times the length of the first groove portion in the extending direction.

In the pump device, the length of the second groove portion in the extending direction is 0.3 to 0.7 times the length of the first groove portion in the extending direction, so that the dynamic pressure is sufficiently generated and the second groove is generated. The second groove portion can be easily arranged between the one groove portions.

Here, it is preferable that the second groove portion has a configuration in which the groove width gradually decreases from the end portion on the outer side in the radial direction toward the end portion on the rotation shaft side.

In the dynamic pressure bearing, the groove width of the second groove is gradually reduced toward the end on the rotation shaft side, so that the gap between the first grooves is created near the rotation shaft where the first grooves are adjacent to each other. Can be narrowed. Therefore, a uniform dynamic pressure can be satisfactorily obtained even near the rotation axis.

The groove width of the second groove portion is preferably 0.6 to 1.0 times the groove width of the first groove portion at the same radial position.

If the groove width of the second groove portion is 0.6 to 1.0 times the groove width at the same radial position of the first groove portion, a sufficient width is secured. Therefore, for example, when the fluid is blood, blood is used. It is possible to suppress clogging and the like.

Further, each of the first and second groove portions may be curved in an arc shape from the end portion on the outer side in the radial direction toward the end portion on the rotation axis side.

Since the dynamic pressure bearing is composed of the first and second groove portions curved in an arc shape, it is possible to obtain a dynamic pressure appropriately dispersed along the radial direction with the rotation of the impeller.

Furthermore, it is preferable that the gap between the first groove portion and the second groove portion extends with a constant width.

In the pump device, since the gap between the first groove portion and the second groove portion extends with a certain width, the grooves can be arranged at an appropriate distance from each other, and the grooves can be arranged evenly on the outer side in the radial direction. Dynamic pressure is obtained.

It is preferable that the radial outer edge portion of the first and second groove portions and the edge portion on the rotation axis side are formed in a flat shape.

In the dynamic pressure bearing, the radial outer edge of the first and second grooves and the edge on the rotation axis side are formed in a flat shape. For example, when the fluid is blood, the radial outer edge or the rotation axis is formed. It is possible to satisfactorily suppress the stagnation of blood on the side edge.

The distance between the edge of the second groove on the rotating shaft side and the radial inner edge of the dynamic bearing is the radial outer edge of the second groove and the radial of the dynamic bearing. It may be wider than the distance from the outer edge.

Further, the edge portion of the second groove portion on the rotation axis side may be located between the central portions of the two first groove portions adjacent to the second groove portion in the extending direction.

According to the present invention, the pump device can rotate the impeller more stably by equalizing the dynamic pressure between the impeller and the housing by a simple configuration.

It is a perspective view of the pump device which concerns on one Embodiment of this invention. It is a side sectional view which shows the state which the pump main body and the drive device of FIG. 1 are separated. It is a top view of the lower housing part which has a bottom side dynamic pressure bearing. 4A is an enlarged plan view of the first groove portion and the second groove portion, and FIG. 4B is a cross-sectional perspective view of the IVB-IVB line of FIG. 4A. FIG. 5A is a diagram simulating the distribution of dynamic pressure generated by the dynamic pressure bearing according to the present embodiment, and FIG. 5B is a diagram simulating the distribution of dynamic pressure generated by the conventional dynamic pressure bearing.

Hereinafter, a suitable embodiment of the pump device according to the present invention will be described, and will be described in detail with reference to the accompanying drawings.

The pump device 10 according to an embodiment of the present invention is an artificial heart-lung machine device 12 that assists (or substitutes for) the cardiopulmonary function of a patient, and is a power source for draining the blood of the patient from the body and sending the blood into the body. Used as a source. As shown in FIG. 1, the pump device 10 is configured as a centrifugal pump having an impeller 14 in the device and flowing a fluid by a centrifugal force accompanying the rotation of the impeller 14.

The heart-lung machine 12 connects the blood removal tube 18 and the blood feeding tube 20 to the pump device 10 to form a circulation circuit for circulating blood with the patient. The blood removal tube 18 has a blood removal lumen 18a inside, the tip opening thereof is placed in a desired biological organ (for example, the left ventricle of the heart), and the patient's blood is sucked through the blood removal lumen 18a. The blood feeding tube 20 has a blood feeding lumen 20a inside, and its tip opening is placed in a desired biological organ (for example, the subclavian artery) to feed blood from the pump device 10 through the blood feeding lumen 20a. .. The artificial heart-lung machine 12 may be configured by connecting a reservoir, an artificial lung, or the like (both not shown) in the middle of the circulation circuit (blood removal tube 18 or blood feeding tube 20) in addition to the pump device 10. As a result, the heart-lung machine 12 can remove foreign substances and oxygenate the blood that has been bleeding from the outside of the body, and return the blood to the patient's body.

Then, as shown in FIG. 2, the pump device 10 according to the present embodiment controls the driving of the pump main body 22 in which the impeller 14 is housed, the drive device 24 for rotating the impeller 14, and the drive device 24. A control unit 26 is provided. Further, the housing 30 of the pump device 10 has a main body side housing 32 constituting the pump main body 22 and a drive side housing 60 constituting the drive device 24.

In the housing 30, the main body side housing 32 and the drive side housing 60 are detachably configured and assembled to each other at the time of use, so that the driving force of the driving device 24 can be transmitted to the impeller 14. After use, the pump body 22 is removed from the drive device 24 and discarded. That is, the pump body 22 is configured as a disposable type that is replaced after each use and is disposable or sterilized. On the other hand, the drive device 24 is configured as a reuse type, and at the next use opportunity, a new pump main body 22 is attached to operate the impeller 14 of the pump main body 22.

The main body side housing 32 of the pump main body 22 is formed in an appearance that can be attached to the drive device 24. Inside the main body side housing 32, an internal space 36 is provided in which the impeller 14 is rotatably accommodated and blood is flown in and out.

The main body side housing 32 has a substantially conical upper housing portion 33 and a cylindrical lower housing portion 34 connected to the lower portion of the upper housing portion 33 and mounted on the drive device 24. The internal space 36 is formed over both the upper housing portion 33 and the lower housing portion 34. The upper housing portion 33 and the lower housing portion 34 are configured to be mutually separable so that the impeller 14 can be taken out.

As shown in FIGS. 1 and 2, the upper housing portion 33 has a blood inflow port 38 connected to the blood removal tube 18 and a blood outflow port 40 connected to the blood feeding tube 20. The blood inflow port 38 is provided in the ceiling portion 33a and the center of the upper housing portion 33 and projects upward, and the blood inflow port 38 communicates with the internal space 36 (hereinafter referred to as the upper space 36a) of the upper housing portion 33 inside the ceiling portion 33a. A road 38a is provided. The blood outflow port 40 projects tangentially from the side portion of the upper space 36a, and an outflow path 40a communicating with the upper space 36a is provided inside the blood outflow port 40.

The upper space 36a has a shape corresponding to the outer shape of the upper housing portion 33 and is formed so as to have a predetermined volume. The fin portion 46 on the upper side of the impeller 14 is arranged in the upper space 36a. The ceiling portion 33a covering the upper space 36a is provided with a ceiling-side dynamic pressure bearing 41 (dynamic pressure bearing in the thrust direction) that rotates the impeller 14 in a non-contact manner when the impeller 14 rotates.

Of the wall portions surrounding the upper space 36a, the central upper part of the lower housing portion 34 is arranged in the central portion of the bottom wall, and the central upper portion is a conical chevron portion 35a facing the inflow path 38a of the blood inflow port 38. It has become. The chevron portion 35a is formed to be curved in a bow shape in a side sectional view, and blood is smoothly flowed into the flow hole 50 of the fin portion 46.

The lower housing portion 34 projects downward from the upper housing portion 33 and is formed in a cylindrical shape having an axial center coaxial with the center of the upper space 36a. At the center of the lower housing portion 34, a shaft cylinder portion 35 that pivotally supports the impeller 14 is provided. The shaft cylinder portion 35 is composed of the above-mentioned chevron portion 35a and an inner peripheral portion 35b connected to the peripheral edge and the lower side of the chevron portion 35a, and has an insertion hole 42 having an opening at the lower end side inside the chevron portion 35a.

Further, inside the lower housing portion 34, a lower space 36b (a part of the internal space 36) communicating with the upper space 36a is formed. The lower space 36b orbits the side of the insertion hole 42 according to the cylindrical shape of the lower housing portion 34, and rotatably accommodates the driven rotating structure portion 48 of the impeller 14. The bottom portion 34a constituting the lower space 36b is provided with a bottom side dynamic pressure bearing 43 (dynamic pressure bearing in the thrust direction) for rotating the impeller 14 in a non-contact manner. The specific configuration of the bottom side dynamic pressure bearing 43 and the above-mentioned ceiling side dynamic pressure bearing 41 will be described in detail later.

As shown in FIGS. 1 and 2, the impeller 14 is formed in a cylindrical shape having a through hole 15 inside. The impeller 14 is housed in the main body side housing 32 by inserting the axle tube portion 35 of the lower housing portion 34 into the through hole 15. A fin portion 46 is provided on the upper portion of the impeller 14, while a driven rotation structure portion 48 is provided on the lower portion of the impeller 14. The impeller 14 in FIG. 2 has a configuration in which a fin portion 46 formed on a separate member and a driven rotating structure portion 48 are mutually fixed, but the impeller 14 is not limited to this, and the fin portion 46 and the driven rotating structure portion are not limited to this. The portion 48 may be integrally molded.

The fin portion 46 is arranged in the upper space 36a and applies centrifugal force to the blood as it rotates. The fin portion 46 includes a flow hole 50 that communicates the through hole 15 with the radial outer side of the fin portion 46. The flow hole 50 is surrounded by an upper shroud 50a, a plurality of side wall portions 50b connected to the shroud 50a and projecting downward, and an upper surface 48a of the driven rotating structure portion 48.

The shroud 50a is a roof of a flow hole 50 that rotates in a non-contact manner with respect to the ceiling portion 33a of the upper housing portion 33 by the ceiling side dynamic pressure bearing 41, and is downward toward the outside in the radial direction according to the shape of the ceiling portion 33a. It is tilted in the direction. Further, the upper surface 48a is also inclined diagonally so as to be substantially parallel to the shroud 50a.

The plurality of side wall portions 50b are designed to have an inclined or curved shape that generates an appropriate centrifugal force according to the rotational state (rotational direction, rotational speed, etc.) of the impeller 14. The shape of the fin portion 46 is not limited to the above, and may be, for example, a configuration in which a plurality of feather-shaped walls (side wall portions 50b) are formed so as not to be provided with a shroud 50a.

The driven rotation structure portion 48 is formed in a cylindrical shape having a thickness in the radial direction of the impeller 14, and the rotational force of the drive device 24 is transmitted and rotates while the pump main body 22 and the drive device 24 are mounted. A driven magnet 54 is installed inside the driven rotating structure portion 48.

The driven magnet 54 is arranged at the same height as the drive magnet 64 of the drive device 24 with the pump main body 22 and the drive device 24 mounted, and forms a magnetic coupling mechanism with the drive magnet 64. For example, the driven magnet 54 is configured in a driven side multi-pole magnetizing ring 55 that orbits the rotation axis O of the impeller 14 with a constant radius. The driven side multi-pole magnetizing ring 55 is magnetized so that a plurality of N poles and S poles are alternately arranged along the circumferential direction. Examples of the material constituting the driven magnet 54 (the driven side multi-pole magnetizing ring 55) include hard magnetic materials such as alnico, ferrite, and neodymium.

On the other hand, the drive device 24 of the pump device 10 includes a drive-side housing 60 and a motor mechanism 62 housed in the drive-side housing 60. Further, the drive device 24 is provided in the motor mechanism 62 and has a drive magnet 64 that constitutes a magnetic coupling mechanism with the driven magnet 54 of the impeller 14.

The drive-side housing 60 has a central convex portion 60a in the central portion on the upper side. The main body side housing 32 of the pump main body 22 and the drive side housing 60 of the drive device 24 have an engagement structure 44 that can be positioned and fixed so as to be detachably detachable from each other. In the present embodiment, the engaging structure 44 has a structure in which the central convex portion 60a is inserted and fitted into the insertion hole 42 of the lower housing portion 34. Needless to say, the engaging structure 44 may adopt various configurations.

Inside the drive-side housing 60, a motor body 70 of the motor mechanism 62 is provided. The motor body 70 rotates the shaft portion 72 at an appropriate rotational speed under the control of the control unit 26. The shaft portion 72 is inserted inside the central convex portion 60a, and the rotation shaft O of the impeller 14 and the axis (rotation shaft O) of the shaft portion 72 are mutually attached with the pump main body 22 and the drive device 24 mounted. Overlap. A drive magnet 64 is fixed to the peripheral surface of the shaft portion 72.

The drive magnet 64 is configured in, for example, a drive-side multi-pole magnetizing ring 65 that orbits the rotating shaft O of the shaft portion 72 with a radius shorter than that of the driven magnet 54. Like the driven magnet 54, the drive-side multi-pole magnetizing ring 65 is magnetized so that a plurality of N-poles and S-poles are alternately arranged along the circumferential direction. As the material constituting the driving magnet 64, the material mentioned in the driven magnet 54 can be appropriately selected.

Further, the controller 26 of the pump device 10 is composed of a well-known computer having an input / output interface (not shown), a memory, and a processor, and controls the drive of the motor mechanism 62. A monitor (not shown), a speaker, an operation button, and the like are provided on the outer surface of the control unit 26, and a user such as a doctor or a nurse sets the drive content of the pump device 10 by operating the operation button. The control unit 26 controls the power supply of the battery based on the user's setting information, and rotates the shaft unit 72 in the range of, for example, 0 to 10000 rpm.

Next, the dynamic pressure bearing 45 (ceiling side dynamic pressure bearing 41 and bottom side dynamic pressure bearing 43) constituting the thrust direction bearing of the impeller 14 will be described with reference to FIGS. 3, 4A and 4B. FIG. 3 is a plan view of the lower housing portion 34 having the bottom side dynamic pressure bearing 43, and in the description of the dynamic pressure bearing 45, the bottom side dynamic pressure bearing 43 will be typically described below. Although the ceiling-side dynamic pressure bearing 41 is provided on the ceiling portion 33a of the inclined upper housing portion 33, it is basically formed in a groove shape symmetrical to the groove shape of the bottom-side dynamic pressure bearing 43. It is possible to obtain the same effect.

In the dynamic pressure bearing 45 according to the present embodiment, the first groove portions 80 and the second groove portions 82 having different shapes are alternately arranged along the circumferential direction around the rotation axis O of the impeller 14 to form an annular groove as a whole. It constitutes a group. The first and second groove portions 80 and 82 extend from the inside to the outside of the dynamic pressure bearing 45. Then, the length in the longitudinal direction (length in the extending direction) L2 along the extending direction of the second groove portion 82 is the length in the longitudinal direction (length in the extending direction) along the extending direction of the first groove portion 80. ) It is formed shorter than L1.

Specifically, the plurality of first groove portions 80 are formed in a substantially trapezoidal shape curved in an arc shape from the radial outer end portion 80a toward the end portion 80b on the rotation axis O side in a plan view. That is, each first groove portion 80 connects the flat radial outer edge portion 81a, the flat rotary shaft side edge portion 81b, and these radial outer edge portions 81a and the rotary shaft side edge portion 81b. It is composed of one curved edge portion 81c and a second curved edge portion 81d. The radial outer edge portion 81a may be connected to the edge portion of the dynamic pressure bearing 45 (the boundary between the bottom portion 34a of the lower housing portion 34 and the outer peripheral wall 34b) as shown by the two-dot chain line in FIG.

The radial outer edge portion 81a and the rotation shaft side edge portion 81b are located at offset in the circumferential direction of the lower housing portion 34, and the first and second curved edge portions 81c and 81d connected to both ends of these edge portions are , It extends in the radial direction and curves in the circumferential direction. The four corner portions 81e to which each of the radial outer edge portion 81a, the rotation shaft side edge portion 81b, the first curved edge portion 81c, and the second curved edge portion 81d are connected are set at appropriate angles, and It is formed in a round angle (R shape).

Similarly, the plurality of second groove portions 82 are also formed in a substantially trapezoidal shape curved in an arc shape from the radial outer end portion 82a toward the end portion 82b on the rotation axis O side in a plan view. That is, each second groove portion 82 is also composed of a flat radial outer edge portion 83a, a flat rotation shaft side edge portion 83b, a first curved edge portion 83c, and a second curved edge portion 83d. ..

The radial outer edge portion 83a and the rotation shaft side edge portion 83b are located at offset in the circumferential direction of the lower housing portion 34, and the first and second curved edge portions 83c and 83d connected to both ends of these edge portions are , It extends in the radial direction and curves in the circumferential direction. The four corner portions 83e to which each of the radial outer edge portion 83a, the rotating shaft side edge portion 83b, the first curved edge portion 83c, and the second curved edge portion 83d are connected are also set at appropriate angles. It is formed in a round angle (R shape).

Therefore, each groove constituting the dynamic pressure bearing 45 has a spiral shape (spiral shape) as a whole in a plan view. Further, the radial outer edge portions 81a and 83a extend in the tangential direction of the turning radius on the radial outer side of the dynamic pressure bearing 45. Similarly, the rotating shaft side edge portions 81b and 83b also extend in the radial direction of the turning radius inside the lower housing portion 34 in the radial direction. The rotation axis side edge portions 81b and 83b are inclined (non-parallel) by a predetermined angle with respect to the radial outer edge portions 81a and 83a.

Then, the hydraulic bearing 45 has a radial outer end 80a (diametric outer edge 81a) of the first groove 80 and a radial outer end 82a (diametric outer edge 83a) of the second groove 82. , Are arranged at the same distance from the rotation axis O. That is, the second groove portion 82 is arranged between the outer portions (diametrically outer end portions 80a) of the first groove portion 80.

On the radial outer side of the dynamic pressure bearing 45, the radial outer end 80a of each first groove 80 and the radial outer end 82a of each second groove 82 are first gaps at equal intervals along the circumferential direction. They are lined up across 84. The first gap 84 extends with a constant width between the adjacent first curved edge portion 81c and the second curved edge portion 83d, or between the second curved edge portion 81d and the first curved edge portion 83c. doing. On the other hand, the second groove portion 82 does not exist inside the dynamic pressure bearing 45 in the radial direction, and the end portions 80b on the rotation axis O side of each first groove portion 80 are second at equal intervals along the circumferential direction. They are lined up with a gap 86 in between.

In the present embodiment, the longitudinal length L2 of the second groove portion 82 is set to be approximately 0.5 times (1/2) the longitudinal length L1 of the first groove portion 80. The length L1 in the longitudinal direction is the dimension of the center line connecting the centers of the radial outer edge portion 81a and the rotation shaft side edge portion 81b and slightly curved in the circumferential direction along the radial direction. Similarly, the longitudinal length L2 is the dimension of the center line connecting the centers of the radial outer edge portion 83a and the rotation axis side edge portion 83b and slightly curved in the circumferential direction along the radial direction. Therefore, the end portion 82b (rotating shaft side edge portion 83b) of the second groove portion 82 on the rotation shaft O side is arranged at a substantially intermediate position in the extending direction of the first groove portion 80.

The length L2 in the longitudinal direction of the second groove portion 82 is not particularly limited, but is in the range of 0.3 to 0.7 times (0.3 ×) the length L1 in the longitudinal direction of the first groove portion 80. It is preferable that L1 ≦ L2 ≦ 0.7 × L1). As a result, the second groove portion 82 can stably generate the dynamic pressure of the fluid. If L2 <0.3 × L1, the second groove 82 becomes too small and it becomes difficult to obtain the dynamic pressure of the fluid. On the contrary, when L2> 0.7 × L1, the end 82b on the rotation shaft O side of the second groove 82 is too close to the rotation shaft O, and the end 80b on the rotation shaft O side of the first groove 80 The second gap 86 between them becomes wide, and it becomes difficult to equalize the distribution of dynamic pressure.

Further, each of the first and second groove portions 80 and 82 has groove widths W1 and W2 (length in the lateral direction) from the radial outer end portions 80a and 82a toward the rotation shaft side end portions 80b and 82b. It is gradually decreasing. Since the groove widths W1 and W2 of the first and second groove portions 80 and 82 are gradually reduced, the first groove portion 80 has a second groove portion 82 from the radial outer end portion 80a adjacent to the second groove portion 82. Even if it is located at the end 80b on the rotation shaft O side that does not exist, the width of the second gap 86 is sufficiently narrowed. Further, the groove width W2 of the second groove portion 82 is in the range of 0.6 to 1.0 times the groove width W1 of the first groove portion 80 at the same radial position (same radius distance from the rotation axis O). It is preferably set to 0.6 × W1 ≦ W2 ≦ 1.0 × W1).

Further, as shown in FIG. 4B, the first groove portion 80 and the second groove portion 82 according to the present embodiment are cut out at the same depth from the surface of the bottom portion 34a. The depths D1 and D2 of the first and second groove portions 80 and 82 may be set in the range of, for example, 0.01 mm to 1 mm. The depths D1 and D2 of the first groove portion 80 and the second groove portion 82 are not limited to the same, and for example, the second groove portion 82 is more than the first groove portion 80 so that an appropriate dynamic pressure can be obtained. May be different from each other, such as deepening.

Next, the operation of the pump device 10 will be described.

A heart-lung machine 12 including a pump device 10 is constructed for a patient who assists cardiopulmonary function. At the time of construction of the heart-lung machine 12, the user connects the blood removal tube 18 and the blood feeding tube 20 to the pump body 22. Then, as shown in FIG. 2, the pump device 10 is assembled by attaching the pump main body 22 to the drive device 24. At this time, the user inserts the lower housing portion 34 into the insertion hole 42, and positions and fixes the pump body 22 and the drive device 24 to each other by the engaging structure 44.

In the mounted state, the driven magnet 54 and the driving magnet 64 are arranged at the same height position from the rotation axis O toward the outside in the radial direction. The driven magnet 54 (driven side multi-pole magnetizing ring 55) and the driving magnet 64 (driving-side multi-pole magnetizing ring 65) that are adjacent to each other in the radial direction have different polarities facing each other to form a magnetic coupling mechanism. Form. That is, the driven side multi-pole magnetizing ring 55 and the driving side multi-pole magnetizing ring 65 generate a magnetic coupling force (magnetic coupling force), and the rotational force of the rotating body 74 can be transmitted to the impeller 14.

Therefore, when the motor mechanism 62 of the drive device 24 rotates the shaft portion 72, the impeller 14 also rotates. Then, the impeller 14 rotates in a non-contact manner with respect to the upper and lower parts of the main body side housing 32 by the dynamic pressure bearing 45 (ceiling side dynamic pressure bearing 41, bottom side dynamic pressure bearing 43) in the thrust direction during rotation.

Specifically, the dynamic pressure bearing 45 shows the distribution of dynamic pressure as shown in FIG. 5A by arranging the first groove portion 80 and the second groove portion 82 alternately along the circumferential direction of the lower housing portion 34. It will be like. Note that FIG. 5A is a diagram simulating the distribution of the dynamic pressure generated by the dynamic pressure bearing 45 when the impeller 14 rotates. The dark-colored portion (high-density region 90) indicates a portion where the dynamic pressure is high, and this high-density region 90 occurs on the first curved edge portions 81c and 83c of the first and second groove portions 80 and 82. ing. On the other hand, the light-colored portion (low density region 92) indicates a portion where the dynamic pressure is low, and this low concentration region 92 is the second curved edge portion 81d of the first and second groove portions 80 and 82. It occurs on the 83d side.

Here, exemplifying the conventional dynamic pressure bearing 100, as shown in FIG. 5B, a plurality of similarly formed arcuate groove portions 102 are arranged side by side along the circumferential direction of the lower housing portion 34. .. In such a structure in which the groove portions 102 are arranged in the circumferential direction, the gap 104 between the groove portions 102 is narrowed on the inner side in the radial direction, while the gap 104 between the groove portions 102 is widened on the outer side in the radial direction. Therefore, in the distribution of the dynamic pressure of the dynamic pressure bearing 100, the high concentration region 106 becomes dense on the inner side in the radial direction, while the high concentration region 106 becomes sparse on the outer side in the radial direction. Therefore, in the dynamic pressure bearing 100, the distribution of the dynamic pressure becomes uneven, and the rotation of the impeller 14 tends to be unstable.

On the other hand, in the dynamic pressure bearing 45 according to the present embodiment, the second groove portion 82, which is shorter than the first groove portion 80, supplements the sparse portion of the first groove portion 80 to generate dynamic pressure. In particular, since the second groove 82 is provided on the outer side in the radial direction in which the dynamic pressure tends to decrease, the dynamic pressure on the outer side in the radial direction can be increased. As a result, the high-concentration region 90 is evenly distributed in the circumferential direction and the radial direction of the bottom portion 34a (ceiling portion 33a) of the main body side housing 32, and the dynamic pressure bearing 45 is distributed from the main body side housing 32 to the impeller 14. Stable separation.

That is, the pump device 10 stably drives the impeller 14 with respect to the main body side housing 32 by the dynamic pressure bearing 45 in the thrust direction (ceiling side dynamic pressure bearing 41 and bottom side dynamic pressure bearing 43). Then, the fin portion 46 of the impeller 14 generates a centrifugal force to allow blood to flow in the order of the inflow path 38a, the internal space 36, the flow hole 50, and the outflow path 40a, so that the blood flows smoothly in the heart-lung machine 12. Can be made to.

As described above, the pump device 10 according to the present embodiment has the following effects.

The pump device 10 has a dynamic pressure bearing 45 in which the first groove portion 80 and the second groove portion 82 having a longitudinal length L2 shorter than the longitudinal length L1 of the first groove portion 80 are alternately arranged in the circumferential direction. doing. As a result, the second groove portion 82 fills the portion having a wide gap between the first groove portions 80 to generate an appropriate dynamic pressure, and reduces the portion where the dynamic pressure becomes sparse. Therefore, the dynamic pressure bearing 45 can stably rotate the impeller 14 in a non-contact state by a uniform dynamic pressure, suppress the generation of hemolysis and thrombus, and allow blood to flow smoothly.

Further, in the pump device 10, the radial outer end 80a of the first groove 80 and the radial outer end 82a of the second groove 82 are arranged at the same distance from the rotation shaft O, so that the second groove 82 Can increase the radial outer dynamic pressure. Moreover, by arranging the first and second groove portions 80 and 82 at equal intervals along the circumferential direction, uniform dynamic pressure can be obtained toward the outer side in the radial direction. Further, since the length L2 in the longitudinal direction of the second groove portion 82 is 0.3 to 0.7 times the length L1 in the longitudinal direction of the first groove portion 80, the first groove portion is sufficiently generated with dynamic pressure. The second groove 82 can be easily arranged between the 80s.

Here, in the dynamic pressure bearing 45, the groove widths W1 and W2 gradually decrease toward the ends 80b and 82b on the O side of the rotating shaft, so that the groove widths W1 and W2 are between the first groove portion 80 and the second groove portion 82. The second gap 86 between the first groove portions 80 can be narrowed near the rotation axis O where the first groove portions 80 are adjacent to each other without changing the width of the first gap 84. Therefore, a uniform dynamic pressure can be satisfactorily obtained even near the rotation axis O.

The groove width W2 of the second groove portion 82 is 0.6 to 1.0 times the groove width W1 of the first groove portion 80, so that the groove width W2 is sufficiently secured and blood clogging is suppressed. can do. Further, the dynamic pressure bearing 45 can obtain the dynamic pressure appropriately dispersed along the radial direction with the rotation of the impeller 14 by the first and second groove portions 80 and 82 curved in an arc shape. Furthermore, in the dynamic pressure bearing 45, the radial outer edges 81a and 83a of the first and second groove portions 80 and 82 and the rotary shaft side edge portions 81b and 83b are formed in a flat shape, so that blood stagnates. Can be satisfactorily suppressed.

The present invention is not limited to the above-described embodiment, and various application examples and modifications can be taken. For example, the dynamic pressure bearing 45 may be formed not only on the main body side housing 32 side but also on the surface of the impeller 14 facing the main body side housing 32. In short, the dynamic pressure bearing 45 may be provided on at least one of the surfaces where the impeller 14 and the housing 30 face each other.

Further, the shapes and the number of formations of the first and second groove portions 80 and 82 constituting the dynamic pressure bearing 45 are not particularly limited. For example, in the first and second groove portions 80 and 82, the radial outer edge portions 81a and 83a and the rotation shaft side edge portions 81b and 83b may be formed in a semicircular shape. Further, the radial outer end 82a of the second groove 82 may be at a position offset radially with respect to the radial outer end 80a of the first groove 80.

Furthermore, as shown by the two-dot chain line in FIG. 3, the radial outer side of the first groove portion 80 is connected to the edge portion of the dynamic pressure bearing 45, and the radial outer side of the second groove portion 82 and the rotary shaft O side. May be configured not to be connected to the edge of the dynamic pressure bearing 45. As a result, the pump device 10 can smoothly guide blood from the radial outer side of the first groove portion 80 connected to the edge portion of the dynamic pressure bearing 45 to the first groove portion 80, and the dynamic pressure can be easily obtained from the blood. It will be possible. In particular, the rotating shaft side edges 81b and 83b of the first and second groove portions 80 and 82 are radially outside the inner peripheral surface of the impeller 14 (not connected to the boundary between the bottom portion 34a and the shaft cylinder portion 35). Due to the configuration, the blood flow space on the rotation axis O side of the first and second groove portions 80 and 82 is narrowed. As a result, blood does not easily escape from the first and second groove portions 80 and 82, and dynamic pressure can be satisfactorily generated.

As shown in FIG. 3, the dynamic pressure bearing 45 has a configuration in which the first groove portion 80 and the second groove portion 82 are alternately arranged one by one along the circumferential direction, and also has various regular arrangements. May be adopted. For example, in the dynamic pressure bearing 45, a first groove group (not shown) in which two first groove 80s are adjacent to each other in the circumferential direction and a second groove group (not shown) in which two second groove 82s are adjacent to each other in the circumferential direction. And can be arranged alternately along the circumferential direction. Further, for example, the dynamic pressure bearing 45 may have a configuration in which two first groove portions 80 are adjacent to each other in the circumferential direction and one second groove portion 82 is alternately arranged in the circumferential direction. Alternatively, the dynamic pressure bearing 45 may have a configuration in which one first groove portion 80 and a second groove portion group in which two second groove portions 82 are adjacent to each other in the circumferential direction are alternately arranged in the circumferential direction.

The number of the first groove portions 80 constituting the first groove portion group or the number of the second groove portions 82 constituting the second groove portion group is not limited to two, and may be three or more. Of course. For example, the dynamic pressure bearing 45 has a first groove group in which three first groove 80s are adjacent to each other in the circumferential direction and a second groove group in which two second groove 82s are adjacent to each other in the circumferential direction. The configuration may be arranged alternately.

10 ... Pump device 12 ... Artificial cardiopulmonary device 14 ... Impeller 22 ... Pump body 24 ... Drive device 30 ... Housing 32 ... Main body side housing 41 ... Ceiling side dynamic pressure bearing 43 ... Bottom side dynamic pressure bearing 45 ... Dynamic pressure bearing 54 ... Driven Magnet 64 ... Drive magnet 80 ... First groove 80a, 82a ... Radial outer end 80b, 82b ... Rotating shaft side end 81a, 83a ... Radial outer edge 81b, 83b ... Rotating shaft side edge 82 ... 2nd groove 84 ... 1st gap 86 ... 2nd gap

Claims (10)

A housing that allows fluids to flow in and out,
With an impeller rotatably housed in the housing,
The surface pairs toward said impeller of said housing, an annular dynamic bearing generating dynamic pressure which the impeller is in a non-contact is provided for the housing with the rotation of said impeller,
The dynamic pressure bearing is configured by alternately arranging first groove portions and second groove portions extending from the inside to the outside in a circumferential direction around the rotation axis of the impeller.
The extending direction of the length of the second groove portion, rather shorter than the length of the first groove extending direction,
The radial outer side of the first groove portion is connected to the edge portion of the dynamic pressure bearing.
The radial outer side of the second groove portion and the rotary shaft side are not connected to the edge portion of the dynamic pressure bearing.
The edge portion of the first groove portion on the rotation axis side and the edge portion of the second groove portion on the rotation axis side are radially outside the inner peripheral surface of the impeller.
A pump device characterized by that. In the pump device according to claim 1,
A pump device characterized in that the second groove portion is arranged between the outer portions of the first groove portion. In the pump device according to claim 1 or 2.
A pump device characterized in that the length of the second groove portion in the extending direction is 0.3 to 0.7 times the length of the first groove portion in the extending direction. In the pump device according to any one of claims 1 to 3.
The second groove portion is a pump device characterized in that the groove width gradually decreases from the end portion on the outer side in the radial direction toward the end portion on the rotation shaft side. In the pump device according to any one of claims 1 to 4.
A pump device characterized in that the groove width of the second groove portion is 0.6 to 1.0 times the groove width at the same radial position of the first groove portion. In the pump device according to any one of claims 1 to 5.
A pump device characterized in that each of the first and second groove portions is curved in an arc shape from an end portion on the outer side in the radial direction toward an end portion on the rotation axis side. In the pump device according to any one of claims 1 to 6.
A pump device characterized in that a gap between the first groove portion and the second groove portion extends with a constant width. In the pump device according to any one of claims 1 to 7.
A pump device characterized in that a radial outer edge portion of the first and second groove portions and an edge portion on the rotation shaft side are formed in a flat shape. In the pump device according to any one of claims 1 to 8.
The distance between the edge of the second groove on the rotation axis side and the radial inner edge of the dynamic bearing is the radial outer edge of the second groove and the radial outer edge of the dynamic bearing. Wider than the distance from the edge,
A pump device characterized by that. In the pump device according to any one of claims 1 to 9.
The edge portion of the second groove portion on the rotation axis side is located between the central portions of the two first groove portions adjacent to the second groove portion in the extending direction.
A pump device characterized by that.

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