Blood pumps and assistive artificial heart systems

Abstract

This invention provides a blood pump that can be miniaturized while maintaining stable motor operation and an assistive artificial heart system that reduces the burden on the user. The motor (14) of the blood pump (10) has: a shaft (32) that passes through a base portion (17) and reaches a pump chamber (R); a stator (30) with a coil (34) wound around it; a permanent magnet (40) through which the stator (30) can be inserted; and a rotor (31) formed by a rotor frame (42) on which the permanent magnet (40) is fixedly mounted on the inner circumferential surface. The rotor (31) has: a lower fixed support (43) that provides shaft support to the rear cover (21) side of the shaft (32); and an upper fixed support (44) that provides shaft support to the pump chamber (R) side relative to the lower fixed support (43) across the stator (30).

Description

Technical Field

[0001] This invention relates to a blood pump and an auxiliary artificial heart system. Background Technology

[0002] Blood pumps that kinetically power blood used to sustain a patient’s life up to a heart transplant and assistive artificial heart systems that use the blood pump to assist part of the heart’s function are well known (see, for example, Patent Document 1).

[0003] The assistive artificial heart system described in Patent Document 1 consists of a blood pump implanted in the body, an artificial blood vessel for connecting to the heart's blood flow, and a control device. The control device is used outside the user's body and is connected to the blood pump via a tube containing a cable (signal line) for driving and controlling the motor and a cooling fluid circulation path for circulating the cooling fluid.

[0004] Patent Document 1 describes a blood pump that delivers blood into a user's body via a delivery mechanism such as a worm gear housed within a pump chamber, allowing blood to flow in from an inlet and out from an outlet within the chamber. This blood pump includes: a delivery mechanism; a motor that drives the delivery mechanism; and a shaft connecting the delivery mechanism and the motor. The motor consists of a rotor, a rotating element with a permanent magnet fixed to the shaft, and a stator, a stationary element with coils wound around the outer circumference of the rotor. This is a so-called internal rotor type motor, where the rotor rotates inside the stator.

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2018-158838 Summary of the Invention

[0007] To reduce the burden on users, blood pumps used in assistive artificial heart systems are required to be miniaturized. In the case of an internal rotor motor, the pressure application point is located near the rotor's rotation axis. Therefore, it is possible to suppress unevenness in the pressure and force direction applied to the rotating sliding member to support the fluid delivery mechanism side of the shaft. However, to obtain the required magnetomotive force, the cross-sectional area of ​​the coil increases, and the axial thickness of the shaft increases. In addition, since the rotor has a single-support structure, the load applied to the worm gear and the load generated by the motor are borne by the fixed-side sliding member, so the support length between the fixed-side sliding member and the shaft is extended to be closer to the rotating-side sliding member than the rotor's overall configuration. If miniaturization of this type of internal rotor motor is desired, the distance between the shaft and the pivot point must be shortened, making it difficult to achieve miniaturization while maintaining operational stability and output.

[0008] Furthermore, the blood pump has a cooling seal fluid circulation path, which circulates a cooling seal fluid (e.g., water for injection) that maintains the lubrication, sealing, and cooling of the sliding parts inside the blood pump. The cooling seal fluid circulation path described in Patent Document 1 passes through the fixed-side sliding member on the fluid delivery mechanism side of the body, at a position closer to the upper side than the fulcrum of the shaft of the fixed-side sliding member, and extends through the fixed-side sliding member in the cross-sectional direction. If, for the purpose of miniaturization (thinning), the cooling seal fluid circulation path is moved to a position closer to the lower side than the starting point of the shaft, the support length of the shaft will be shortened, making it difficult to miniaturize the blood pump.

[0009] Therefore, the present invention was made to solve at least one of the above-mentioned problems. The technical problem to be solved is to provide a blood pump that can be miniaturized while maintaining stable motor operation and an assistive artificial heart system that can reduce the burden on the user.

[0010] [1] The blood pump of the present invention moves blood by centrifugal force of a delivery mechanism that rotates due to a motor, characterized in that it has: a body housing the motor; and a base portion fixed to the body and forming a pump chamber housing the delivery mechanism together with the base portion, the motor having: a rotating shaft that passes through the base portion and reaches the pump chamber; a stator having a through hole in the center through which the shaft can be inserted and a coil wound thereon; a permanent magnet having a stator through hole through which the stator can be inserted; and a coil having a coil wound thereon. The rotor is formed by a generally bowl-shaped rotor frame with sidewalls and bottom, the sidewalls of which the permanent magnet is fixedly mounted on the inner circumferential surface, and the bottom opening has a central hole for axial support of the shaft. The liquid delivery mechanism is axially supported at the top end of the shaft in the pump chamber and has: a lower fixed support for axial support of one end of the shaft; and an upper fixed support for axial support of the other side relative to the lower fixed support across the stator, the lower fixed support being configured to protrude axially outward from the body.

[0011] [2] In the blood pump of the present invention, it is preferable that it also has a rear cover that closes the space for housing the motor of the body, and the rear cover side of the shaft is supported by a lower rotating support that rotates integrally with the shaft, and the liquid delivery mechanism side of the shaft is supported by an upper rotating support that rotates integrally with the shaft, and the upper fixed support is supported by the upper rotating support.

[0012] [3] In the blood pump of the present invention, it is preferable that grooves are formed on the outer peripheral surfaces of the lower rotating support and the upper rotating support, which allow the cooling sealing fluid to flow.

[0013] [4] In the blood pump of the present invention, it is preferable that the stator is surrounded by a stator housing.

[0014] [5] Preferably, the blood pump of the present invention further comprises: an upper cooling and sealing fluid circulation path that passes through the pedestal portion and the upper fixed support in the outer peripheral direction, and delivers cooling and sealing fluid between the upper fixed support and the upper rotating support; and a lower cooling and sealing fluid circulation path that passes through the rear cover and the lower fixed support in the outer peripheral direction, and delivers cooling and sealing fluid between the lower fixed support and the lower rotating support.

[0015] [6] The assisted artificial heart system of the present invention is characterized by having: a blood pump described in any one of [1] to [5] above; and a control device disposed outside the body and circulating a cooling sealing fluid to the blood pump.

[0016] The blood pump of the present invention moves blood through the centrifugal force of a fluid delivery mechanism that rotates due to a motor. Since the blood pump described in Patent Document 1 is a so-called internal rotor type motor with a single-support shaft, it is preferable to lengthen the axial length used to support the shaft in order to stably transmit the load (output) generated by the motor to the fluid delivery mechanism. However, lengthening the axial length makes it difficult to miniaturize the blood pump. The blood pump of the present invention uses a so-called external rotor type motor with the rotor arranged around the outer periphery of the stator. The rotor has a two-end support structure that supports the shaft via a lower fixed support and an upper fixed support. Therefore, since the load (output) generated by the motor can be stably transmitted to the fluid delivery mechanism, the distance between the lower and upper fixed supports can be shortened, enabling miniaturization of the blood pump.

[0017] Furthermore, the blood pump of the present invention includes: an upper cooling and sealing fluid circulation path that supplies cooling and sealing fluid to the space between an upper fixed support and an upper rotating support on one side (the fluid delivery mechanism side); and a lower cooling and sealing fluid circulation path that supplies cooling and sealing fluid to the space between a lower fixed support and a lower rotating support on the other side (the side below the motor). In this way, the blood pump has a rotor with supports at both ends, stably transmitting the motor's load (output) to the fluid delivery mechanism (worm gear), and the cooling and sealing fluid circulation path is configured as two separate systems, thus improving the lubrication and sealing performance of the aforementioned sliding parts, and enabling miniaturization.

[0018] As explained above, the blood pump according to the present invention can be miniaturized while maintaining stable motor operation. Furthermore, the assistive artificial heart system according to the present invention, due to the aforementioned blood pump, reduces the burden on the user. Attached Figure Description

[0019] Figure 1 This is a schematic diagram representing the structure of an auxiliary artificial heart system 1 in which a blood pump 10 is implanted in the body for use.

[0020] Figure 2 This is a longitudinal sectional view of the blood pump 10 cut along a cutting line passing through the central axis G.

[0021] Figure 3 This is a diagram showing the configuration of the force-bearing point Pa, the action point Em, and the fulcrum A and B in the blood pump described in Patent Document 1.

[0022] Figure 4 This diagram shows the configuration of the action point Em, the force point Pa, and the fulcrums A and B in the blood pump 10 of this embodiment.

[0023] Symbol Explanation

[0024] 1-Assisted artificial heart system; 2-User; 3-Autologous heart; 4, 5-Artificial blood vessels; 6-Control device; 7-Tube; 10-Blood pump; 11-Liquid delivery mechanism; 11a-Wheel gear; 12-Inlet; 13-Outlet; 14-Motor; 15-Body; 16-House; 17-Base; 18-Side wall; 20-Connecting tube; 21-Rear cover; 21a-Support holding part; 22-Space; 30-Stator; 30a-Through hole; 31-Rotor; 32-Shaft; 33-Coil core; 34-Coil; 35-Stator housing; 40-Permanent magnet; 40 a-Stator insertion hole; 41-Rear yoke; 42-Rotor frame; 42a-Side wall; 42b-Bottom; 42c-Center hole; 42d-Inner circumferential surface; 43-Lower fixed support; 44-Upper fixed support; 45-Lower rotating support; 46-Fixing pin; 47-Upper rotating support; 47a-Groove; 50-Sealing ring; 51-Buffer ring; 60-Upper cooling and sealing fluid circulation path; 61-Lower cooling and sealing fluid circulation path; A; B-Fulcrum; CS-Cooling and sealing fluid; Em-Point of action; F1, F2-Load; G-Central shaft; Pa-Force point; R-Pump chamber. Detailed Implementation

[0025] The following is for reference Figures 1-4 The artificial heart system 1 and blood pump 10 according to embodiments of the present invention will be described.

[0026] Structure of Assisted Artificial Heart System 1

[0027] Figure 1This is a schematic diagram illustrating the structure of an assistive artificial heart system 1, in which a blood pump 10 is implanted in the body for use. The assistive artificial heart system 1 consists of a blood pump 10, an artificial blood vessel 4, an artificial blood vessel 5, a control device 6, and a tube 7. The blood pump 10 is implanted in the body of the user 2. The artificial blood vessel 4 connects the blood pump 10 to the left ventricle of the user 2's own heart 3 (not shown). The artificial blood vessel 5 is used to return blood from the blood pump 10 to the user 2's body. The control device 6 is located outside the user 2's body. The tube 7 connects the control device 6 to the blood pump 10.

[0028] The control device 6 has the following functions: while controlling the operation of the blood pump 10, it supplies cooling liquid (hereinafter referred to as cooling sealing fluid CS) to the blood pump 10, and then recovers and filters the cooling sealing fluid CS. Although not shown in the figure, the inside of the pipe 7 includes: a cable (signal line) connecting the control device 6 and the blood pump 10; an upper cooling sealing fluid circulation path 60, which circulates the cooling sealing fluid CS inside the blood pump 10; and a sealing fluid flow path connected to the lower cooling sealing fluid circulation path 61 (see reference). Figure 2 ).

[0029] When the blood pump 10 is installed in the body and used, in order to reduce the burden on the user 2 (and improve the quality of life), it is required to miniaturize the blood pump 10 while maintaining its original function. Therefore, the structure for achieving miniaturization of the blood pump 10 will be described.

[0030] Structure of blood pump 10

[0031] Figure 2 This is a longitudinal sectional view of the blood pump 10 cut along a cutting line through the central axis G. The blood pump 10 is a device that delivers blood from the left ventricle into the user 2's body through the centrifugal force of the delivery mechanism 11 housed in the pump chamber R, causing blood to flow in from the inlet 12 and out from the outlet 13. The blood pump 10 includes: a delivery mechanism 11; a motor 14 that applies rotational force to the delivery mechanism 11; a body 15 that supports the motor 14; and a shell 16 that is fitted and fixed to the body 15 to form the pump chamber R. The body 15 is a generally bowl-shaped component having a pedestal portion 17 and a side wall portion 18 that stands upright from the pedestal portion 17 and opens downwards. The pedestal portion 17 divides the pump chamber R into a space 22 that houses the motor 14.

[0032] The shell 16 has a generally funnel shape, with an inlet 12 at its upper top end that communicates with the artificial blood vessel 4, and its lower edge fixed to the base portion 17 of the body 15. The shell 16 and the base portion 17 constitute the pump chamber R. Furthermore, the shell 16 is provided with a connecting pipe portion 20 for connecting to the artificial blood vessel 5, and the connecting pipe portion 20 is provided with an outlet 13 that communicates with the pump chamber R.

[0033] The liquid delivery mechanism 11 has the function of moving blood through centrifugal force due to rotation. Figure 2 In the example shown, the worm gear 11a performs this function. The liquid delivery mechanism 11 is housed in the pump chamber R formed by the base portion 17 and the housing 16 of the body 15. A rear cover 21 is fixed to the side wall portion 18 of the body 15 in such a way as to close the opening on the opposite side of the pump chamber R opposite to the base portion 17. The motor 14 is housed in the space 22 formed between the base portion 17, the side wall portion 18, and the rear cover 21. Next, the structure of the motor 14 will be described.

[0034] The motor 14 consists of a stator 30, a rotor 31, and a shaft 32 that rotatably fixes the rotor 31. The stator 30 is formed by winding a coil 34 onto a coil core 33 made of laminated steel sheet. The stator 30 is housed in a water-resistant stator housing 35, constructed as a ring-shaped unit. The stator housing 35 prevents the intrusion of coolant CS into the interior. The stator 30 has a through hole 30a and is fixed to the inner bottom surface of the rear cover 21; the through hole 30a has a diameter that does not contact the shaft 32. The coil 34 is wound on the stator 30 in a manner that achieves a predetermined magnetomotive force.

[0035] The rotor 31 is composed of a permanent magnet 40, a rear yoke 41, and a rotor frame 42. The permanent magnet 40 has a stator insertion hole 40a through which the stator 30 is inserted into the central part. The rear yoke 41 is fixed to the outer periphery of the permanent magnet 40. The rotor frame 42 fixes the permanent magnet 40 and the rear yoke 41 to the shaft 32. The permanent magnet 40 has multiple groups arranged in a circumferential direction with alternating N and S poles. The rotor frame 42 has a flat, roughly bowl-shaped design, and the permanent magnet 40 is fixed to the inner circumferential surface of the side wall 42a by the rear yoke 41. At the bottom 42b of the rotor frame 42, there is a central hole 42c that passes through the bottom 42b. The shaft 32 is pressed into this central hole 42c for integration. The rotor 31 rotates about the central axis G of the shaft 32, causing the worm gear 11a fixed to the top end of the shaft 32 to rotate.

[0036] The shaft 32 passes through the through hole 30a of the stator 30, and one end is supported by the lower fixed support 43. The other end of the shaft 32 passes through the base portion 17 of the machine body 15 and protrudes into the pump chamber R, where it is supported by the upper fixed support 44 fixed to the base portion. The lower fixed support 43 is fixed to the inside of the support holding portion 21a protruding downwards from the rear cover 21. A lower rotating support 45 is disposed at the lower end of the shaft 32, embedded within the lower fixed support 43. A fixing pin 46 is inserted through the shaft 32 at the lower end, and a groove 45a is formed on the lower rotating support 45 to engage with the fixing pin 46. When the rotor 31 is a single unit, the lower rotating support 45 is slidably moved from below the shaft 32 while the groove 45a is engaged with the fixing pin 46, thereby making the lower rotating support 45 an integral part of the shaft 32 for rotation. In other words, the lower side of the shaft 32 is axially supported by the lower rotating support 45 on the lower fixed support 43. The lower rotating support 45 can be detached from the shaft 32 by sliding downwards.

[0037] An upper rotating support 47 is provided above the shaft 32, embedded within the upper fixed support 44. Similar to the lower rotating support 45, a retaining pin 46, passing through the shaft 32, is inserted into the upper fixed support 44. A groove 47a is formed on the upper rotating support 47 to engage with the retaining pin 46. Before assembling the rotor 31 onto the machine body 15, the upper rotating support 47 is slidably moved from the upper side (worm gear 11a side) of the shaft 32 while engaging the groove 47a with the retaining pin 46, thereby making the upper rotating support 47 and the shaft 32 integral and rotating together. In other words, the shaft 32 is axially supported on the upper fixed support 44 by the upper rotating support 47. The upper rotating support 47 can be detached from the shaft 32 by sliding upwards (worm gear 11a side).

[0038] exist Figure 2 In the example shown, the rotor 31 is axially supported by the lower fixed support 43 and the upper fixed support 44 via the lower rotating support 45 and the upper rotating support 47. This is a structure for assembling the motor 14 into the blood pump 10 after unitization. Alternatively, it can be configured so that the lower rotating support 45 and the upper rotating support 47 are not used, but the shaft 32 is directly supported by the lower fixed support 43 and the upper fixed support 44. The shaft 32 has axial clearance between the lower fixed support 43 and the upper fixed support 44, within a range that does not impede the rotation of the worm gear 11a.

[0039] Furthermore, when the rotor 31 rotates, the side wall portion 42a of the rotor frame 42 has a sufficient gap that does not contact the side wall portion 18 of the housing 15, and the inner peripheral surface of the permanent magnet 40 has a gap that does not contact the outer peripheral surface of the stator 30 (stator housing 35). However, in order to improve magnetic efficiency, it is preferable to reduce the gap between the inner peripheral surface of the permanent magnet 40 and the outer peripheral surface of the stator 30 within the range of non-contact. Compared with the inner rotor type motor described in Patent Document 1, in which the rotor rotates inside the stator, the motor 14 configured as described above is referred to as an outer rotor type motor.

[0040] To reduce the surface pressure applied to each support and prevent sintering of each support, while also reducing the rotational load, the axial contact length between the lower rotating support 45 and the lower fixed support 43, and the axial contact length between the upper rotating support 47 and the upper fixed support 44, are appropriately set. Furthermore, the motor 14 is controlled to maintain a constant rotation direction.

[0041] Above the upper fixed support 44 of the shaft 32, a sealing ring 50, a buffer ring 51, and a liquid delivery mechanism 11 (worm gear 11a) are stacked sequentially from the upper side end 44a of the upper fixed support 44. The worm gear 11a is assembled to the shaft 32 from the upper side, thereby pressing the sealing ring 50 against the upper side end face 44a of the upper fixed support 44 by means of the elastic buffer ring 51. In addition, since the buffer ring 51 has a diametrical clearance with the shaft 32, the load that hinders the rotation of the rotor 31 is minimized.

[0042] Next, refer to Figure 2 The structure of the upper cooling sealant circulation path 60 and the lower cooling sealant circulation path 61 will be described. Above the body 15 (on the worm gear 11a side), the upper cooling sealant circulation path 60 passes through the pedestal portion 17 and the upper fixed support 44 from the outer periphery. Only the portion of the pedestal portion 17 constituting the upper cooling sealant circulation path 60 protrudes, and the rest of the periphery is formed thinly to achieve weight reduction. After passing through the upper cooling sealant circulation path 60, the cooling sealant CS permeates into the gap between the upper fixed support 44 and the upper rotating support 47, and the radial gap between the upper fixed support 44 and the shaft 32. On the outer peripheral surface of the upper rotating support 47, a groove that bends obliquely upwards is formed over a span in the vertical direction (illustration omitted). The cooling sealing fluid CS moves within the tank while lubricating the space between the upper rotating support 47 and the upper fixed support 44. Simultaneously, it moves upwards and penetrates the tiny gap between the upper fixed support 44 and the sealing ring 50, thus preventing blood from entering the motor 14 while lubricating the space between the upper fixed support 44 and the sealing ring 50.

[0043] The lower coolant circulation path 61 extends from the outer periphery through the lower rear cover 21 and the lower fixed support 43. Only the portion of the rear cover 21 constituting the lower coolant circulation path 61 protrudes, and the rest of the periphery is thinned to achieve weight reduction. The coolant CS passes through the lower coolant circulation path 61 and then permeates into: the gap between the lower fixed support 43 and the lower rotating support 45; the radial gap between the lower fixed support 43 and the shaft 32; the radial gap between the lower rotating support 45 and the shaft 32; and the area between the top surfaces of the lower rotating support 45 and the shaft 32 and the lower fixed support 43. On the outer periphery of the lower rotating support 45, an upwardly curved groove (not shown) is formed over a span in the vertical direction. The cooling sealant CS moves within the tank, lubricating the lower rotating support 45 and the lower fixed support 43, while simultaneously moving upwards to the space 22 housing the motor 14 to cool the rotor 31 and stator 30. Since the stator 30 is surrounded by the stator housing 35, the cooling sealant CS will not penetrate the interior and affect the performance of the motor 14.

[0044] As explained above, the cooling sealant CS supplied from the upper cooling sealant circulation path 60 functions as lubricant and sealant between the upper fixed support 44 and the upper rotating support 47. Additionally, the cooling sealant CS supplied from the lower cooling sealant circulation path 61 functions as lubricant between the lower fixed support 43 and the lower rotating support 45 and as coolant for the motor 14. To ensure that an appropriate amount of cooling sealant CS permeates the small gaps between the upper fixed support 44 and the upper rotating support 47, and between the lower fixed support 43 and the lower rotating support 45, the delivery pressure from the control device 6 is appropriately controlled. Furthermore, the cooling sealant CS supplied to the blood pump 10 is... Figure 2 The cooling sealant recovery path (not shown) on the back side of the blood pump 10 is drawn in and circulated into the interior of the blood pump 10 after being filtered by the control device 6.

[0045] Next, refer to Figure 3 , Figure 4 The miniaturization strategy of the blood pump 10 will be explained. Furthermore, Figure 3 , Figure 4 The diagram illustrates the relationship between the point of action Em, the point of force Pa, and the fulcrum A and B, based on the motor's support structure. This diagram shows the differences from Patent Document 1 and enables the miniaturization of the blood pump 10.

[0046] Figure 3 This is a diagram illustrating an example of the configuration of the force-bearing point Pa, the point of action Em, and the fulcrums A and B in the blood pump described in Patent Document 1. (See diagram below.) Figure 3As shown, fulcrums A and B are positioned between the force-bearing point Pa and the point of application Em. The point of application Em is the end position of the shaft, which is the location where the motor load F2 (output) is generated. The force-bearing point Pa is the location where the load F1 is generated due to the rotation of the worm gear. In the blood pump of Patent Document 1, fulcrum A is the worm gear side end of the contact portion between the fixed-side sliding member and the shaft, and fulcrum B is the rotor side end of the contact portion between the fixed-side sliding member and the shaft. Furthermore, the locations where the loads F1 and F2 are generated are set for calculating the surface pressure or load.

[0047] That is, in the blood pump described in Patent Document 1, fulcrums A and B are arranged between the point of action Em and the point of force Pa. At each point, when the distance between the point of force Pa and fulcrum A is taken as L1, the distance between fulcrum A and fulcrum B is taken as L2, and the distance between fulcrum B and the point of action Em is taken as L3, there exists a relationship of L1≈L2 and (L1+L2)>>L3. If (L1+L2+L3) is reduced, the force transmission efficiency of the rotor is improved. However, the rotor (shaft) is supported by fulcrums A and B, which is a so-called single-support structure. Therefore, if L2 is shortened, the load F1 at the point of force Pa will change due to the oscillation of the shaft, making it difficult to maintain stable motor drive. In other words, in the blood pump described in Patent Document 1, it can be said that it is difficult to achieve miniaturization by shortening the distance between the fulcrums.

[0048] Figure 4 This diagram illustrates the configuration of the action point Em, the force point Pa, and the fulcrums A and B in the blood pump 10 of this embodiment. Figure 4 As shown, the point of application Em is positioned between fulcrum A and fulcrum B. Fulcrum A is the position where shaft 32 is supported by the upper fixed support 44, and fulcrum B is the position where shaft 32 is supported by the lower fixed support 43, which is the end position of shaft 32. The point of application Em is the position of the load F2 (output) generated by motor 14. The point of force Pa is the position of the load F1 generated by the rotation of worm gear 11a. Furthermore, the positions where loads F1 and F2 are generated are set for calculating surface pressure or load.

[0049] Let L4 be the distance between the point of force application Pa and the fulcrum A, L5 be the distance between the fulcrum A and the point of action Em, and L6 be the distance between the point of action Em and the fulcrum B. The rotor 31 is supported by both fulcrums A and B, forming a so-called two-end support structure. Therefore, if L4 < L5, then, similar to Patent Document 1, the load F1 can suppress the load F2 (output) generated by the motor 14. Furthermore, since L4 < (L5 + L6) of the blood pump 10, the variation of the load F1 at the point of force application Pa is smaller than that of the structure described in Patent Document 1, enabling miniaturization. Moreover, by using an external rotor type motor, only the lower fixed support 43 protrudes from the blood pump 10, preventing a significant increase in the volume of the blood pump 10. This allows for a longer distance L6 between the point of action Em and the fulcrum B, suppressing surface pressure at fulcrums A and B.

[0050] The blood pump 10 described above uses a so-called external rotor type motor with the rotor 31 disposed on the outer periphery of the stator 30. The rotor 31 has a two-end support structure that supports the shaft 32 via a lower fixed support 43 and an upper fixed support 44. Therefore, since the load F2 (output) generated by the motor 14 can be stably transmitted to the fluid delivery mechanism 11 (worm gear 11a), the distance (L5+L6) between the lower fixed support 43 and the upper fixed support 44 can be shortened, and the blood pump 10 can be miniaturized. Of course, miniaturization of the blood pump 10 also enables weight reduction.

[0051] Furthermore, only the lower mounting bracket 43 of the blood pump 10 protrudes axially outward from the body 15 (rear cover 21). Therefore, even if the distance between the lower mounting bracket 43 and the upper mounting bracket 44 is increased sufficiently (L5+L6), miniaturization and weight reduction can be achieved as a whole. As described above, the blood pump 10 can be miniaturized while maintaining stable operation of the motor 14, thus reducing the burden on the user 2.

[0052] One side of the rotor 31 is supported by a lower fixed support 43 via a lower rotating support 45 that is integral with the shaft 32 and rotates on its own, while the other side is supported by an upper fixed support 44 via an upper rotating support 47 that is integral with the shaft 32 and rotates on its own. The lower rotating support 45 and the upper rotating support 47 are configured to be detachable from the shaft 32. By making it such a structure, the assemblability of the motor 14 is improved, and the rotor 31 can be modularized and easily assembled into the body 15, or it can be easily disassembled from the body 15.

[0053] In addition, grooves are formed on the outer peripheral surfaces of the lower rotating support 45 and the upper rotating support 47 to allow the coolant CS to flow. This allows the coolant CS to circulate on the sliding surfaces of the lower fixed support 43 and the lower rotating support 45 and the upper fixed support 44 and the upper rotating support 47, thereby improving lubricity.

[0054] Furthermore, the stator 30 is enclosed by the stator housing 35. As already described, the blood pump 10 is configured such that the cooling sealant CS flows from the lower cooling sealant circulation path 61 into the space 22 containing the stator 30, and the cooling sealant CS enters from this flow path into the space 22 containing the stator 30. Thus, by enclosing the stator 30 with the stator housing 35, the stator 30 and the rotor 31 can be cooled while being protected from the cooling sealant CS.

[0055] Furthermore, the blood pump 10 includes: an upper cooling and sealing fluid circulation path 60, which delivers cooling and sealing fluid CS to the space between the upper fixed support 44 and the upper rotating support 47 on the side of the delivery mechanism 11; and a lower cooling and sealing fluid circulation path 61, which delivers cooling and sealing fluid CS to the space between the lower fixed support 43 and the lower rotating support 45 on the side below the motor 14. With these two systems, the upper cooling and sealing fluid circulation path 60 and the lower cooling and sealing fluid circulation path 61, the blood pump 10 can achieve lubrication and miniaturization of the sliding parts, even for an external rotor type motor with a two-end support structure.

[0056] In addition, the assistive artificial heart system 1 includes a blood pump 10. Since the blood pump 10 can be miniaturized, it can reduce the burden on the user 2 when using the blood pump 10 after it is implanted in the body.

Claims

1. A blood pump that moves blood by centrifugal force through a delivery mechanism rotated by a motor, characterized in that, It comprises: a body that houses the motor; and a housing that is fixed to the base portion of the body and together with the base portion forms a pump chamber that houses the liquid delivery mechanism. It also has a rear cover that seals off the space containing the motor of the machine body. The motor includes: a rotating shaft passing through the base portion and reaching the pump chamber; a stator with a coil wound around it and having a through hole in the center through which the shaft can be inserted; a permanent magnet having a stator through hole through which the stator can be inserted; and a rotor consisting of a generally bowl-shaped rotor frame having sidewalls and a bottom, the sidewalls fixing the permanent magnet to an inner circumferential surface, and a central hole for shaft support at the bottom. The liquid delivery mechanism is supported by a shaft at the top end of the shaft within the pump chamber. It comprises: a lower fixed support for supporting one end of the shaft; and an upper fixed support for supporting the other side of the shaft across the stator relative to the lower fixed support. The lower fixed support is configured to protrude axially outward from the body; It also has: an upper cooling sealant circulation path that passes through the pedestal part and the upper fixed support from the outer periphery direction, and delivers the cooling sealant between the upper fixed support and the upper rotating support; The lower cooling sealant circulation path passes through the rear cover and the lower fixed support from the outer periphery, and delivers the cooling sealant between the lower fixed support and the lower rotating support; The rotor is arranged around the outer periphery of the stator. The rotor has a two-end support structure that supports the shaft through a lower fixed support and an upper fixed support, thereby shortening the distance between the lower fixed support and the upper fixed support.

2. The blood pump according to claim 1, characterized in that, The rear cover side of the shaft is supported by a lower rotating support that rotates integrally with the shaft, and by a lower fixed support. The upper rotating support, which rotates integrally with the shaft, supports the liquid delivery mechanism side of the shaft via the upper fixed support.

3. The blood pump according to claim 2, characterized in that, Grooves that allow cooling sealant to flow are formed on the outer peripheral surfaces of the lower rotating support and the upper rotating support.

4. The blood pump according to claim 1, characterized in that, The stator is surrounded by a stator shell.

5. An assistive artificial heart system, characterized in that, It has: a blood pump as described in any one of claims 1 to 4; And a control device located outside the body that circulates the cooling sealant to the blood pump.

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