Pumping device

Abstract

In an impeller (30) constituting a pump device (10), a plurality of communication holes (104a-104d) are formed that allow communication between the hollow inside thereof and the inner space (64) of a housing (28). The impeller (30) has a supported part (120) supported by a support shaft (68) provided in the housing (28). On the bottom surface of the supported part (120), a bearing part (122) that receives the leading end (70) of the support shaft and communication paths (124a-124d) that allow individual communication between each of the communication holes and the bearing part are formed.

Description

Technical Field

[0001] The present invention relates to a pump device including a housing that houses an impeller.

Background Art

[0002] Pump devices are used as blood circulation devices that cause blood (fluid) to flow in artificial heart-lung devices. As this type of pump device, those including an impeller that rotates within a housing are widely known. As described in Japanese Patent Application Laid-Open No. 2002-315824, a support shaft is provided within the housing, and the impeller is rotatably supported by the support shaft. That is, the impeller has a supported portion at its rotation center. A bearing portion for receiving the support shaft is provided on the bottom surface of this supported portion.

[0003] Note that the hollow interior of the impeller and the interior space of the housing communicate with each other via a washout hole formed in the impeller. In this configuration, when the impeller rotates about the support shaft and the supported portion, due to the centrifugal force generated along with this rotation, new blood is drawn from the blood inlet port into the interior space of the housing. The blood enters the hollow interior of the impeller through the clearance between the housing and the impeller. The blood further reaches the interior space of the housing via the washout hole, and then is led out of the housing from the blood outlet port. That is, a blood flow occurs.

Summary of the Invention

[0004] As a result of intensive studies by the present inventor, it has been found that a small amount of blood tends to remain at the contact portion between the support shaft and the bearing portion.

[0005] A main object of the present invention is to provide a pump device capable of suppressing the retention of fluids such as blood in the impeller.

[0006] According to one embodiment of the present invention, in a pump device having an impeller holding a permanent magnet and a housing that houses the impeller, The impeller has a plurality of communication holes formed therein that connect the hollow interior of the impeller to the internal space of the housing, and a supported portion that is positioned around the plurality of communication holes and supported by a support shaft provided in the housing. A pump device is provided in which a bearing portion for receiving the tip of the support shaft and a communication passage that individually connects each of the communication holes to the bearing portion are formed on the bottom surface of the supported portion.

[0007] In this invention, a communication passage is formed connecting the bearing portion and the communication hole. Therefore, when a fluid such as blood enters the bearing portion during the rotation of the impeller, the fluid, subjected to centrifugal force, is guided to the communication hole through the communication passage. In other words, the fluid is quickly discharged from the bearing portion. As a result, it becomes difficult for the fluid to remain at the contact point between the bearing portion and the support shaft.

[0008] In other words, by forming a connecting passage, the fluid can reach the bearing section. Retention This can suppress the action. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view of the main part of an artificial cardiopulmonary bypass machine configured to incorporate a pump device according to an embodiment of the present invention. [Figure 2] This is a longitudinal cross-sectional view of the main part of the pump device. [Figure 3] Figure 2 is a schematic longitudinal cross-sectional view of the impeller that makes up the pump device. [Figure 4] This is a schematic longitudinal cross-sectional view of a magnet holder with a permanent magnet in place. [Figure 5] This is a disassembled perspective view of the magnet holder. [Figure 6] This is a top-down perspective view showing the appearance of the impeller. [Figure 7] This is a bottom view of the vane support section that makes up the impeller, as seen from the hollow interior side of the impeller. [Figure 8] This is a longitudinal cross-sectional view of a key part showing the flow of fluid (blood) within the pump device when the impeller rotates. [Modes for carrying out the invention]

[0010] Hereinafter, preferred embodiments of the pump device according to the present invention will be described in detail with reference to the attached drawings. In this embodiment, blood is used as an example of the fluid, but the pump device may be used to circulate fluids other than blood.

[0011] Figure 1 is a schematic perspective view of the main parts of an artificial cardiopulmonary bypass machine 12 that incorporates the pump device 10 according to this embodiment. This artificial cardiopulmonary bypass machine 12 functions as a power source for drawing blood from the patient's body and pumping new blood into the body, thereby assisting (or replacing) the patient's cardiopulmonary function.

[0012] The cardiopulmonary bypass machine 12 connects a blood withdrawal tube 18 and a blood return tube 20 to the pump device 10 to form a circulatory circuit that circulates blood between the machine and the patient. The blood withdrawal tube 18 has a blood withdrawal lumen 18a inside, and its tip opening is placed in a desired organ (e.g., the left ventricle of the heart) to draw blood from the patient through the blood withdrawal lumen 18a. The blood return tube 20 has a blood return lumen 20a inside, and its tip opening is placed in a desired organ (e.g., the subclavian artery) to deliver blood from the pump device 10 through the blood return lumen 20a.

[0013] Although not specifically shown in the diagram, the cardiopulmonary bypass machine 12 may also have a configuration in which a reservoir, artificial lung, etc., are further provided in the middle of the circulatory circuit (blood withdrawal tube 18 and blood delivery tube 20). With this configuration, the cardiopulmonary bypass machine 12 can return blood that has been withdrawn from the body, treated to remove foreign substances and oxygenate, back into the patient's body.

[0014] The pump device 10 includes an impeller 30 housed within a housing 28. The centrifugal force generated by the rotation of this impeller 30 causes the blood to flow as described above. In other words, the pump device 10 is a so-called centrifugal pump.

[0015] The pump device 10 will be described with reference to Figure 2. As shown in Figure 2, the pump device 10 comprises a drive device 32 for rotating the impeller 30, a pump body 34 in which the impeller 30 is housed, and a control unit 36 ​​for controlling the drive of the drive device 32. The housing 28 also has a drive-side housing 38 which constitutes the drive device 32 and a body-side housing 40 which constitutes the pump body 34.

[0016] A central protrusion 42 is formed on the drive-side housing 38, while an insertion hole 44 is formed on the main body-side housing 40. The main body-side housing 40 is positioned and fixed to the drive-side housing 38 when the central protrusion 42 is inserted (engaged) into the insertion hole 44. The main body-side housing 40 and the drive-side housing 38 can be separated from each other by disengaging the central protrusion 42 from the insertion hole 44 (disengaging it).

[0017] As described above, the housing 28 is configured so that the main body housing 40 and the drive side housing 38 can be detachably attached and detached, and by assembling them together during use, the driving force of the drive unit 32 can be transmitted to the impeller 30. After use, the pump body 34 is removed from the drive unit 32 and discarded. In other words, the pump body 34 is configured as a disposable type that is replaced after each use and is either disposable or sterilized. On the other hand, the drive unit 32 is configured as a reusable type, and at the next opportunity to use it, a new pump body 34 is attached and the impeller 30 of this pump body 34 is operated.

[0018] The drive unit 32 includes a motor 50 housed within the drive-side housing 38. The central protrusion 42 is hollow, and the rotating shaft 52 of the motor 50 is housed inside its hollow interior.

[0019] At the lower end of the rotating shaft 52, a fixed-side repulsive magnet 53 having an annular shape is attached. In the illustrated example, the inner peripheral side of the fixed-side repulsive magnet 53 is magnetized to be the S pole and the outer peripheral side is magnetized to be the N pole. However, conversely, it may be magnetized such that the inner peripheral side is the N pole and the outer peripheral side is the S pole. As will be described later, the fixed-side repulsive magnet 53 repels the movable-side repulsive magnet 54 provided on the impeller 30.

[0020] At the upper end of the rotating shaft 52, a drive-side coupling magnet 56 is held. The drive-side coupling magnet 56 has an annular shape and constitutes a magnetic coupling mechanism with a movable-side coupling magnet 58 (permanent magnet) provided on the impeller 30. As the rotating shaft 52 rotates at an appropriate rotational speed under the control action of the control unit 36, the drive-side coupling magnet 56 performs a circular motion.

[0021] The drive-side coupling magnet 56 is magnetized such that the polarities alternate along the circumferential direction. That is, in the drive-side coupling magnet 56, the arrangement of N pole, S pole, N pole, S pole is repeated along the circumferential direction.

[0022] The control unit 36 is composed of a well-known computer having an input / output interface, a memory, and a processor (not shown) and controls the drive of the motor 50. On the outer surface of the control unit 36, a monitor, a speaker, operation buttons, etc. (not shown) are provided. A user such as a doctor or a nurse sets the drive content of the pump device 10 by operating the operation buttons. The control unit 36 controls the supply of power from the battery based on the user's setting information and rotates the rotating shaft 52, for example, within the range of 0 to 80000 rpm.

[0023] On the other hand, the main body-side housing 40 of the pump main body 34 has a cylindrical lower housing portion 60 attached to the drive device 32 and an upper housing portion 62 that is continuous with the upper part of the lower housing portion 60 and has a substantially conical shape. The lower housing portion 60 and the upper housing portion 62 are configured to be mutually separable so that the impeller 30 can be taken out.

[0024] Inside the main body housing 40, an internal space 64 is formed, extending from the lower housing portion 60 to the upper housing portion 62. The impeller 30 is rotatably housed in this internal space 64, and blood flows in and out through it.

[0025] A shaft cylinder portion 66 for supporting the impeller 30 is provided at the center of the lower housing portion 60. The hollow interior of this shaft cylinder portion 66 becomes an insertion hole 44 into which the central protrusion 42 is inserted. A fitting hole 67 is formed at the center of the upper end of the shaft cylinder portion 66, and a pivot 68 (support shaft) is fitted into this fitting hole 67. At the tip of the pivot 68 is a shaft-shaped support portion 70, which is a curved portion with a spherical notch shape. The shaft-shaped support portion 70 rotatably supports the impeller 30 from the inside.

[0026] The upper housing portion 62 has a blood inlet port 74 connected to the blood withdrawal tube 18 and a blood outlet port 78 connected to the blood delivery tube 20. The blood inlet port 74 is located on the ceiling and in the center of the upper housing portion 62 and protrudes upward, and an inlet passage 74a is provided inside it that communicates with the upper housing portion 62 side of the internal space 64. The blood outlet port 78 protrudes tangentially from the side of the internal space 64, and an outlet passage 78a is provided inside it that communicates with the internal space 64.

[0027] The impeller 30 is housed in the main body housing 40 so as to cover the shaft cylinder portion 66. In this housed state, there is a small clearance between the outer circumferential wall of the impeller 30 and the inner circumferential wall of the lower housing portion 60, and between the inner circumferential wall of the impeller 30 and the outer circumferential wall of the shaft cylinder portion 66. The spacing of this clearance depends on the size of the pump body 34, but is set to a range of approximately 0.1 mm to 1 mm.

[0028] As shown in detail in Figure 3, the impeller 30 holds a magnet holder 80. In this embodiment, the magnet holder 80 holds the movable repulsion magnet 54 and the movable coupling magnet 58.

[0029] Specifically, as shown in Figures 4 and 5, the magnet holder 80 consists of a small-diameter cylindrical portion 84 with a small inner and outer diameter and thin walls, and a large-diameter cylindrical portion 86 with a larger inner and outer diameter and thicker walls compared to the small-diameter cylindrical portion 84. The axial dimension of the small-diameter cylindrical portion 84 is smaller than that of the large-diameter cylindrical portion 86.

[0030] An outer stepped portion 88 is formed on the outer circumferential wall of the magnet holder 80 based on the difference in outer diameter between the small-diameter cylindrical portion 84 and the large-diameter cylindrical portion 86. In addition, a stepped insertion hole 90 is formed in the magnet holder 80, extending along its height direction (axial direction). Inside the stepped insertion hole 90, an inner stepped portion 92 is formed based on the difference in inner diameter between the small-diameter cylindrical portion 84, which is the lower part of the magnet holder 80, and the large-diameter cylindrical portion 86, which is the upper part.

[0031] The movable repulsion magnet 54 is held on the outer circumferential wall of the small-diameter cylindrical portion 84. The outer stepped portion 88 acts as a stopper wall that blocks the movable repulsion magnet 54. The inner circumferential side of the movable repulsion magnet 54 is magnetized to have the opposite polarity to the outer circumferential side of the fixed repulsion magnet 53. Meanwhile, the lower end surface of the movable coupling magnet 58 abuts against the inner stepped portion 92. The movable coupling magnet 58 is magnetized such that its polarity alternates along the circumferential direction. That is, the movable coupling magnet 58 has a repeating arrangement of N pole, S pole, N pole, S pole.

[0032] The material of the magnet holder 80 configured as described above is not particularly limited, but in this embodiment, since the material of the impeller 30 is polyethylene as described later, it is preferable to select polyethylene in the same way.

[0033] As shown in Figure 3, the impeller 30 has a cylindrical cover portion 100. This cylindrical cover portion 100 encloses the magnet holder 80, along with the movable repulsive magnet 54 and the movable coupling magnet 58. The shaft cylinder portion 66 enters the hollow interior of the cylindrical cover portion 100. There is a predetermined distance between the outer circumferential wall of the shaft cylinder portion 66 and the inner circumferential wall of the cylindrical cover portion 100.

[0034] The upper part of the cylindrical cover portion 100 is connected to a series of hollow vane support portions 102 that taper in diameter as they move away from the cylindrical cover portion 100 (upwards). The vane support portions 102 have a shape as if they were cut off during the convergence process. As a result, as shown in Figures 6 and 7, washout holes 104a to 104d are formed at the top of the vane support portions 102, serving as communication holes that connect the hollow interior of the impeller 30 with the internal space 64 of the main body housing 40. The washout holes 104a to 104d are separated from adjacent ones by a bridge portion 106, which will be described later. When the bridge portion 106 is removed, the washout holes 104a to 104d are connected in a nearly circular shape.

[0035] Multiple vanes 108 (for example, 8) are erected on the tapered surface of the vane support portion 102, extending from the cylindrical cover portion 100 towards the washout holes 104a to 104d. Each vane 108 curves gently toward the center of the cylindrical cover portion 100 as it travels from the cylindrical cover portion 100 towards the washout holes 104a to 104d. The vanes 108 impart centrifugal force to the blood as the impeller 30 rotates. The spaces between adjacent vanes 108 form flow passages for the blood.

[0036] Bridge sections 106 are individually provided on the outer peripheral edges of the washout holes 104a to 104d, extending toward the rotation center of the impeller 30. In this embodiment, four bridge sections 106 are provided. A supported section 120, having a cylindrical section 114 at the bottom and a tapered diameter section 116 at the top, is disposed at the rotation center of the impeller 30, and the bridge sections 106 are connected to the cylindrical section 114. As a result, the supported section 120 is integrally connected to the vane support section 102.

[0037] As shown in Figure 7, a concave receiving portion 122, which serves as a bearing portion, is formed on the lower surface of the cylindrical portion 114, which is the bottom surface of the supported portion 120. The inner wall surface of the concave receiving portion 122 is curved to correspond to the curved shape of the shaft-shaped support portion 70. The outer wall surface of the shaft-shaped support portion 70 abuts against the inner wall surface of the concave receiving portion 122, thereby rotatably supporting the impeller 30 on the pivot 68.

[0038] Furthermore, connecting passages 124a to 124d are formed on the lower surface of the cylindrical portion 114, recessing from the cylindrical portion 114 toward the tapered diameter portion 116. The groove-shaped connecting passages 124a to 124d each extend linearly from the washout holes 104a to 104d to the concave receiving portion 122. Therefore, the washout holes 104a to 104d are individually connected to the concave receiving portion 122 via the connecting passages 124a to 124d.

[0039] As can be understood from this, for example, the washout hole 104a communicates with the concave receiving portion 122 via the communication passage 124a, and further communicates individually with the washout holes 104b to 104d via the communication passages 124b to 124d. The same applies to the washout holes 104b to 104d.

[0040] The connecting passages 124a to 124d are formed at a position slightly offset from the radius of the cylindrical portion 114. That is, the virtual extension line L, which virtually extends the connecting passages 124a to 124d into the concave receiving portion 122, does not pass through the center O of the concave receiving portion 122 (or the cylindrical portion 114). Therefore, connecting passages 124a and 124c do not face each other, and similarly, connecting passages 124b and 124d do not face each other. Note that offsetting the connecting passages 124a to 124d is not essential. That is, the connecting passages 124a to 124d may be formed to extend along the radius of the cylindrical portion 114.

[0041] The impeller 30, configured as described above, is made from a single molded piece. That is, the impeller 30 is a single component that integrally has a cylindrical cover portion 100, a vane support portion 102, vanes 108, a bridge portion 106, and a supported portion 120. Therefore, no seams, which are traces of connections between components, are observed in the impeller 30. In this embodiment, the material of the impeller 30 is polyethylene. Furthermore, the positions of the movable coupling magnet 58 and the movable repulsion magnet 54 held in the magnet holder 80 substantially coincide with the design position.

[0042] The impeller 30 can be manufactured by injection molding. Specifically, for example, a magnet holder 80, which holds a movable repulsive magnet 54 on the outer circumferential wall of a small-diameter cylindrical portion 84 and a movable coupling magnet 58 on an inner stepped portion 92, is placed in the cavity of a mold, and then molten polyethylene resin is injected into the cavity.

[0043] The molten resin is filled into the cavity, deforming to conform to its shape and form the impeller 30. Subsequently, the molten resin filling the cavity cools and hardens, resulting in the impeller 30 with the magnet holder 80 enclosed within the cylindrical cover portion 100. The upper end of the magnet holder 80 is covered by the vane support portion 102. It is not a problem if the molten resin and the magnet holder 80 fuse together during the process from injection to cooling and hardening.

[0044] Here, polyethylene exhibits relatively large shrinkage during cooling and curing. Therefore, it is difficult to manufacture an impeller with movable repulsion magnets 54 and movable coupling magnets 58 enclosed within a cylindrical cover 100 using polyethylene. In other words, in this case, the molten resin shrinks during cooling and curing. Consequently, the magnets surrounded by the molten resin move along with the molten resin. As a result, the magnets become misaligned. Thus, when polyethylene is selected as the material for the impeller, it is not easy to obtain an impeller with the magnets positioned in the design location.

[0045] In contrast, this embodiment uses a magnet holder 80. The magnet holder 80, which holds the movable repulsion magnet 54 and the movable coupling magnet 58, is relatively heavy due to its own weight. For this reason, the magnet holder 80 is difficult to move even when pressed by the molten resin that is contracting inward in the diametrical direction. Consequently, the molten resin that forms the cylindrical cover portion 100 is prevented from contracting significantly. For this reason, an impeller 30 can be obtained in which the magnet holder 80 is positioned at a predetermined design position, in other words, at a desired position.

[0046] Thus, according to this embodiment, it is possible to manufacture an impeller 30 in which the movable coupling magnet 58 and the movable repulsion magnet 54 are arranged in predetermined positions, even when using polyethylene, which has a large sink mark, as the material. By using this impeller 30, a pump device 10 can be obtained in which various characteristics such as output and efficiency match the design values.

[0047] Furthermore, since the impeller 30 is obtained as a single molded product, only one injection molding machine is required. In other words, there is no need to prepare separate injection molding machines for each component in order to obtain multiple components individually. In addition, equipment and solvents for joining components together are unnecessary, and the joining process is also eliminated. As a result, the production equipment for the impeller 30 can be simplified, and capital investment can be reduced. Moreover, the process of obtaining the impeller 30 is also simplified.

[0048] Next, the operation of the pump device 10 will be explained.

[0049] The cardiopulmonary bypass machine 12, including the pump unit 10, is constructed for patients who require assistance with cardiopulmonary function. When constructing the cardiopulmonary bypass machine 12, the user connects the blood withdrawal tube 18 and the blood delivery tube 20 to the prepared pump body 34. The pump unit 10 is then assembled by attaching the pump body 34 to the drive unit 32. At this time, the user inserts the central protrusion 42 of the drive-side housing 38 into the insertion hole 44 of the main body-side housing 40, thereby positioning and fixing the pump body 34 and the drive unit 32 relative to each other.

[0050] As shown in Figure 2, when the pump body 34 is attached to the drive unit 32, the movable coupling magnet 58 and the drive coupling magnet 56 have opposite polarities facing each other. As a result, a magnetic coupling force is generated between the two coupling magnets 56 and 58. This magnetic coupling force makes it possible to transmit the rotational driving force of the rotating shaft 52 to the impeller 30.

[0051] In this state, the motor 50 of the drive unit 32 is biased, and the rotating shaft 52 rotates accordingly. Consequently, the drive-side coupling magnet 56 provided on the rotating shaft 52 rotates in a circular motion. The drive-side coupling magnet 56 and the movable-side coupling magnet 58 are magnetized such that the north poles and south poles are arranged alternately along the direction of rotation. Therefore, when the drive-side coupling magnet 56 rotates in a circular motion, the like poles of the drive-side coupling magnet 56 and the movable-side coupling magnet 58 repel each other, while the opposite poles attract each other. Based on this, the impeller 30 rotates. Of course, the center of rotation is the supported part 120, and more specifically, the contact point between the axial support part 70 and the concave receiving part 122.

[0052] Consequently, centrifugal force is generated in the vane 108 rotating in the internal space 64 of the main body housing 40. Due to this centrifugal force, blood flows in the following order, as shown by arrow A in Figure 8: inlet passage 74a, internal space 64, hollow interior of cylindrical cover 100, washout holes 104a to 104d, internal space 64, and outlet passage 78a. In this process, some of the blood that enters the hollow interior of cylindrical cover 100 tends to move towards the concave receiving portion 122.

[0053] Here, as described above, communication passages 124a to 124d are formed on the lower surface of the supported portion 120 (see Figure 7 in particular). As a result, the centrifugal force generated by the rotation of the impeller 30 creates a flow of blood from the concave receiving portion 122 towards the washout holes 104a to 104d via the communication passages 124a to 124d. In Figure 8, this flow is shown as arrow B. In other words, when the impeller 30 rotates, the blood flow shown by arrow A and the blood flow shown by arrow B occur simultaneously inside the pump device 10.

[0054] Therefore, blood that enters the concave receiving portion 122 reaches the washout holes 104a to 104d via the communication passages 124a to 124d. Then, it flows through the hollow interior of the cylindrical covering portion 100 and merges with the blood that has reached the washout holes 104a to 104d, and proceeds into the internal space 64. As described above, by forming the communication passages 124a to 124d on the lower surface of the supported portion 120, blood that enters the concave receiving portion 122 is discharged from the concave receiving portion 122. As a result, it is possible to suppress the accumulation of blood in the concave receiving portion 122.

[0055] In particular, when the connecting passages 124a to 124d are offset with respect to the radius of the cylindrical portion 114, the flow shown by arrow B is more likely to occur. Therefore, blood is less likely to remain in the concave receiving portion 122. As a result, the accumulation of blood in the concave receiving portion 122 can be further suppressed.

[0056] Furthermore, as described above, the impeller 30 is a seamless, one-piece molded product. Therefore, the impeller 30 has excellent strength. Also, because the impeller 30 is made of polyethylene, it is less prone to cracking. Consequently, a decrease in pump efficiency and other performance aspects of the pump device 10 is suppressed.

[0057] Furthermore, the positions of the movable coupling magnet 58 and the movable repulsion magnet 54 correspond precisely to the design positions. As a result, various characteristics such as the output and pump efficiency of the pump device 10 can be obtained at values ​​that match the design specifications.

[0058] The present invention is not particularly limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0059] For example, the number of washout holes is not limited to four. Also, the number of connecting passages can be set according to the number of washout holes.

[0060] Furthermore, the inner circumferential wall of the stepped insertion hole 90 of the magnet holder 80 may be exposed. In this case, the shaft portion 66 is inserted into the stepped insertion hole 90.

[0061] Alternatively, the impeller may be constructed by joining multiple components together. In this case, two housing chambers can be formed when the components are joined together, and the movable repulsion magnet 54 and the movable coupling magnet 58 can be individually housed in each housing chamber. In other words, in this configuration, there is no particular need to use the magnet holder 80.

[0062] The impeller material is not particularly limited to polyethylene, but may also be other resins. Specific examples of other resins include polycarbonate, polyacetal, polypropylene, styrene-based resins (GPPS, HIPS, SAN, ABS), and acrylic resins (MBS, PMMA).

Claims

1. In a pump device (10) having an impeller (30) holding a permanent magnet (58) and a housing (28) housing the impeller, The impeller has a plurality of communication holes (104a to 104d) formed therein that connect the hollow interior of the impeller to the internal space (64) of the housing, and a supported portion (120) that is positioned surrounded by the plurality of communication holes and supported by a support shaft (68) provided in the housing. The supported portion has a bearing portion (122) that receives the tip of the support shaft, and communication passages (124a to 124d) on its bottom surface that individually connect each of the communication holes to the bearing portion. The bearing portion is formed as a concave shape relative to the bottom surface of the supported portion. The pump device wherein the connecting passage is formed in a shape that is recessed relative to the bottom surface of the supported portion.

2. A pump device according to claim 1, wherein the tip of the support shaft is a curved portion (70).

3. A pump device according to claim 1 or 2, wherein the impeller has a vane support portion (102) that supports a vane (108), the supported portion is connected to the vane support portion via a bridge portion (106), and the plurality of communication holes are partitioned by the bridge portion.

4. A pump device according to any one of claims 1 to 3, further comprising a magnet holder (80) made of a hollow body and holding the permanent magnet in its inner circumferential wall, wherein the impeller is an integrally molded product that covers at least the outer circumferential wall of the magnet holder.

5. A pump device according to claim 4, wherein the impeller and the magnet holder are made of polyethylene.

6. A pump device according to any one of claims 1 to 4, wherein the impeller is made of polyethylene, polycarbonate, polyacetal, polypropylene, styrene resin, or acrylic resin.

7. A pump device according to any one of claims 1 to 6, wherein the communication passage is linear in shape, and the communication passage is formed at a position in which a virtual extension line (L) that virtually extends from the communication passage does not pass through the bearing portion.

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