A blood pump

Abstract

The application discloses a blood pump, comprising an impeller, a pump shell and a motor assembly, the pump shell is used for conveying blood and has an inlet and an outlet, the impeller is arranged in the pump shell, the motor assembly has a rotating shaft, the rotating shaft is connected with the impeller to drive the blood in the pump shell to flow from the inlet to the outlet, a first gap is formed between the end of the motor assembly towards the side where the impeller is located and the shaft end surface of the impeller, the motor assembly has a flow channel, the inlet of the flow channel is used for introducing external fluid, the outlet of the flow channel is communicated with the first gap and is used for guiding at least part of the fluid in the flow channel to the first gap. The application introduces external fluid to flush the first gap through the flow channel, and the phenomenon of blood coagulation in the flow channel and the first gap is reduced.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and more particularly to a blood pump. Background Technology

[0002] Blood pumps are divided into two categories: one is the type with an internal motor, in which the motor shaft directly drives the impeller, and the motor enters the human body along with the catheter; the other is the type with an external motor, in which the impeller is driven by a flexible shaft, and the motor does not enter the human body along with the catheter and impeller.

[0003] In related technologies, the motor-embedded blood pump circulates blood through the main channel formed by the space between the motor and the outer casing, and the secondary channel formed by the rotor and stator inside the motor. This requires high motor performance and can easily cause side effects such as blood clotting that are harmful to human health. Summary of the Invention

[0004] In view of this, embodiments of this application aim to provide a blood pump to improve blood pump performance and improve blood clotting.

[0005] To achieve the above objectives, embodiments of this application provide a blood pump, comprising:

[0006] impeller;

[0007] A pump housing for transporting blood has an inlet and an outlet, and the impeller is disposed inside the pump housing;

[0008] A motor assembly with a rotating shaft connected to the impeller to drive blood in the pump housing from the inlet to the outlet;

[0009] A first gap is formed between the end of the motor assembly facing the side where the impeller is located and the shaft end face of the impeller;

[0010] The motor assembly has a flow channel with an inlet for introducing external fluid and an outlet communicating with the first gap for guiding at least a portion of the fluid from the flow channel into the first gap.

[0011] In some embodiments, the motor assembly includes a circumferential housing and a flow guide shroud having a shaft hole through which the rotating shaft passes. The flow guide shroud is disposed at one end of the circumferential housing near the impeller. The shaft end faces of the flow guide shroud and the impeller form the first gap. A rotational gap is formed between the circumferential outer surface of the rotating shaft and the hole wall of the shaft hole. The rotational gap constitutes at least one outlet of the flow channel.

[0012] In some embodiments, the motor assembly includes a first seal disposed inside an axial second end of the circumferential housing and sealing the second end of the circumferential housing; a flow guide is disposed on the side of the first seal facing the impeller; the flow guide, the first seal, and the circumferential surface of the shaft together define a cavity region through which fluid in the flow channel flows to the rotation gap.

[0013] In some embodiments, the outer wall of the portion of the shaft used to define the cavity region is formed with an axially extending helical groove.

[0014] In some embodiments, the motor assembly includes a fluid conduit for inputting fluid, the fluid conduit being disposed on the outer surface of the circumferential housing and extending from a first axial end of the circumferential housing to a second axial end of the circumferential housing, the space within the fluid conduit defining a portion of the flow channel, and the end of the fluid conduit communicating with the cavity region.

[0015] In some implementations, the sidewall of the flow guide is formed with a connection port, and the outlet end of the fluid tube is connected to the connection port.

[0016] In some implementations, there are multiple fluid tubes, and the sidewall of the flow guide shroud has multiple connection ports, each of which corresponds to a fluid tube, wherein the multiple connection ports are arranged at intervals along the circumference of the flow guide shroud.

[0017] In some embodiments, a second gap is defined between the end faces of the first seal and the flow deflector facing each other, and a portion of the fluid in the cavity region flows out through the second gap.

[0018] In some embodiments, the flow deflector is located axially outside the circumferential housing, and the end face of the flow deflector and the axial end face of the circumferential housing are at least partially spaced apart and define a first opening, through which at least a portion of the fluid in the second gap flows out.

[0019] In some embodiments, the pump housing is formed with a support post, the circumferential outer surface of the flow guide is formed with a groove, the support post is inserted into the groove, a third gap is formed between the support post and the groove wall of the groove, the third gap communicates with the second gap, and at least a portion of the fluid in the second gap flows through the third gap to the first gap.

[0020] In some embodiments, the shaft is at least partially hollow and defines a portion of the flow channel, and the portion of the shaft defining the cavity region is provided with a through hole through which fluid in the flow channel flows to the cavity region.

[0021] In this embodiment of the blood pump, a first gap is formed between the end of the motor assembly facing the impeller and the shaft end face of the impeller. The motor assembly has a flow channel, the inlet of which is used to introduce external fluid, and the outlet of which communicates with the first gap to guide at least a portion of the fluid in the flow channel to the first gap. This application reduces the phenomenon of blood clotting in the flow channel and the first gap by introducing external fluid through the flow channel to flush the first gap. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a blood pump provided in an embodiment of this application;

[0023] Figure 2 for Figure 1 A sectional view;

[0024] Figure 3 for Figure 1 Enlarged view of the connection between the impeller and the motor assembly;

[0025] Figure 4 for Figure 1 Schematic diagram of the structure of the pump casing and the flow guide;

[0026] Figure 5 for Figure 4 Exploded view;

[0027] Figure 6 A cross-sectional view of another blood pump provided in an embodiment of this application;

[0028] Figure 7 for Figure 6 Enlarged view of point A in the middle;

[0029] Figure 8 for Figure 6 A magnified view of a portion of the central axis;

[0030] Figure 9 A cross-sectional view of a rotating shaft along its vertical axis provided in an embodiment of this application;

[0031] Figure 10 A cross-sectional view of another rotating shaft along the vertical axis provided in an embodiment of this application.

[0032] Explanation of reference numerals in the attached figures

[0033] Impeller 1; Pump housing 2; Inlet 2a; Outlet 2b; Support 21; Ring rib 22; Motor assembly 3; Flow channel 3a; Rotation clearance 3b; Cavity area 3c; Second clearance 3d; First opening 3e; Rotating shaft 31; Spiral groove 31a; Through hole 31b; Circumferential housing 32; Flow guide shroud 33; Shaft hole 33a; Connection port 33b; Slot 33c; First seal 34; Fluid pipe 35; First clearance a; Third clearance b. Detailed Implementation

[0034] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but should not be used to limit the scope of this application.

[0035] In the description of the embodiments of this application, the terms "first", "second" and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of the embodiments of this application, the terms "first end" and "second end" refer to the directions shown in the accompanying drawings, and the arrows in the drawings indicate the direction of fluid flow.

[0037] This application provides a blood pump; please refer to... Figure 1 and Figure 2 The blood pump includes an impeller 1, a pump housing 2, and a motor assembly 3.

[0038] The pump housing 2 is used to transfer blood and has an inlet 2a and an outlet 2b.

[0039] Impeller 1 is installed inside pump casing 2, that is, the inlet 2a and outlet 2b of pump casing 2 are located on opposite sides of impeller 1 along the axial direction.

[0040] The motor assembly 3 has a rotating shaft 31, which is connected to the impeller 1 to drive the blood in the pump housing 2 to flow from the inlet 2a to the outlet 2b.

[0041] In other words, the motor assembly 3 can drive the impeller 1 to rotate at high speed inside the pump housing 2 through the rotating shaft 31, forming a negative pressure near the inlet 2a of the blood pump, so that the blood in the ventricle can smoothly enter the pump housing 2 from the inlet 2a. Through the work done by the impeller 1, the mechanical energy is converted into the kinetic energy and pressure potential energy of the blood, which is discharged from the outlet 2b and enters the arterial blood vessels, thus achieving the purpose of ventricular assist.

[0042] The connection method between the rotating shaft 31 and the impeller 1 is not limited. They can be integrally formed, or they can be connected as independent components.

[0043] It should be noted that the motor assembly 3 is built-in, and is inserted into the patient's body along with the pump housing 2 and the impeller 1.

[0044] Please see Figure 1 , Figure 2 and Figure 3 A first gap a is formed between the end of the motor assembly 3 facing the side of the impeller 1 and the shaft end face of the impeller 1. The motor assembly 3 has a flow channel 3a. The inlet of the flow channel 3a is used to introduce external fluid, and the outlet of the flow channel 3a is connected to the first gap a to guide at least a portion of the fluid in the flow channel 3a to the first gap a.

[0045] It should be noted that the fluid can be physiological saline, glucose, or heparin, etc. After the fluid flows through the flow channel 3a to flush the first gap a, it flows into the human blood vessels through the outlet 2b and participates in blood circulation.

[0046] It is understandable that when the motor assembly 3 drives the impeller 1 to rotate, at least some of the blood inside the pump housing 2 will remain in the first gap a, posing a risk of blood clotting. The blood pump of this embodiment introduces external fluid through the flow channel 3a to flush the first gap a, reducing blood clotting in the first gap a, reducing the impact of blood clots or other blood deposits on the blood transmission of the pump housing 2 and the rotation of the shaft 31, and improving the pumping performance of the blood pump.

[0047] In one embodiment, please refer to Figure 2 to Figure 3 or Figure 6 to Figure 7 The motor assembly 3 includes a circumferential housing 32 and a flow guide 33. The flow guide 33 has a shaft hole 33a through which the rotating shaft 31 passes. The flow guide 33 is located at one end of the circumferential housing 32 near the impeller 1.

[0048] A first gap a is formed between the guide shroud 33 and the shaft end face of the impeller 1. A rotational gap 3b is formed between the circumferential outer surface of the rotating shaft 31 and the hole wall of the shaft hole 33a. The rotational gap 3b constitutes at least one outlet of the flow channel 3a. That is, the guide shroud 33 is disposed between the circumferential outer shell 32 and the impeller 1. The hole wall of the shaft hole 33a and the circumferential outer surface of the rotating shaft 31 form an axially extending rotational gap 3b. After the external fluid flows into the rotational gap 3b from the flow channel 3a, it is flushed by the rotation of the rotating shaft 31, and part of the fluid flows into the first gap a along the rotational gap 3b. At the same time, the guide shroud 33 is provided at the second end of the circumferential outer shell 32, which increases the difficulty of blood clotting when flowing through the guide shroud 33 to the second end of the circumferential outer shell 32, thereby improving the performance of the motor assembly 3.

[0049] For example, the end face of the flow guide shroud 33 near the pump housing 2 protrudes towards the interior of the pump housing 2 and protrudes beyond the flow guide surface. That is, the flow guide shroud 33 has a streamlined shape that conforms to the hemodynamic characteristics, forming an effective flow guide structure. After the blood passes through the impeller 1 to increase its pressure potential energy and kinetic energy, it flows towards the outlet 2b through the flow guide surface formed by the flow guide shroud 33, reducing the loss of blood pressure potential energy and reducing the generation of coagulation at the outlet 2b.

[0050] The connection method between the circumferential housing 32 and the pump housing 2 is not limited. For example, it can be glued or welded.

[0051] In some implementations, the circumferential housing 32 is welded to the pump housing 2, which improves the connection strength between the circumferential housing 32 and the pump housing 2.

[0052] In one embodiment, please refer to Figure 1 and Figure 2Multiple support pillars 21 are formed at one end of the pump housing 2 near the circumferential outer shell 32. The multiple support pillars 21 are arranged at intervals along the circumference of the pump housing 2, and the interval between two adjacent support pillars 21 forms a liquid outlet 2b. In this way, multiple liquid outlets 2b are formed on the side wall of the pump housing 2 without increasing the axial or radial dimensions of the pump housing 2, and without increasing the difficulty of inserting the blood pump.

[0053] For example, please refer to Figure 1 , Figure 2 , Figure 4 and Figure 5 The pump casing 2 includes a ring rib 22, which is disposed at one end of the support column 21 near the circumferential outer shell 32. The ring rib 22 is circular, and the support column 21 is connected to the second end of the ring rib 22. The first end of the ring rib 22 is connected to the circumferential outer shell 32. In this way, the contact area at the connection between the pump casing 2 and the circumferential outer shell 32 is increased, and the connection strength between the pump casing 2 and the circumferential outer shell 32 is further increased.

[0054] In one embodiment, please refer to Figure 3 or Figure 7 The motor assembly 3 includes a first seal 34, which is disposed inside the axial second end of the circumferential housing 32 and seals the second end of the circumferential housing 32. A flow guide 33 is disposed on the side of the first seal 34 facing the impeller 1. In other words, the first seal 34 can prevent fluid from flowing from the second end of the circumferential housing 32 into the interior of the circumferential housing 32.

[0055] The circumferential surfaces of the flow guide 33, the first seal 34, and the rotating shaft 31 together define the cavity region 3c, through which the fluid in the flow channel 3a flows to the rotation gap 3b.

[0056] Understandably, the drive unit of the motor assembly 3 is housed within the circumferential housing 32. This drive unit includes a stator, windings, and a magnet connected to the rotating shaft 31. The drive unit can drive the rotating shaft 31 to rotate. In other words, the drive unit of the motor assembly 3 is sealed by the first seal 34, preventing blood and fluids from flowing into the circumferential housing 32 and affecting the drive unit, thus extending the service life of the motor assembly 3.

[0057] In this embodiment, the fluid in the flow channel 3a easily flows into the cavity region 3c, and then can flow more smoothly and evenly to the rotation gap 3b. In this way, by forming the cavity region 3c, the size of the rotation gap 3b is made smaller, and by utilizing the high viscosity of blood, the phenomenon of blood backflow into the rotation gap 3b is reduced.

[0058] It is understandable that if the fluid flows directly into the rotation gap 3b, the outlet of the flow channel 3a needs to be set on the side wall of the rotation gap 3b. In this case, if the rotation gap 3b is small, the fluid inlet at the rotation gap 3b will have a large back pressure and cannot flow in smoothly; if the rotation gap 3b is large, it will affect the stability of the rotating shaft 31, and the blood in the pump casing will easily backflow into the rotation gap 3b.

[0059] In one embodiment, please refer to Figure 8 The outer wall of the portion of the rotating shaft 31 used to define the cavity region 3c has an axially extending spiral groove 31a. It can be understood that the spiral groove 31a is used for flow guidance, enabling fluid to flow through the rotating shaft 31 within the cavity region 3c, thereby achieving the purpose of flushing and anti-coagulation.

[0060] In one embodiment, please refer to Figure 2 to Figure 3 or Figure 6 to Figure 7 The rotating shaft 31 is used to define the area of ​​the cavity region 3c, where the radial dimension is increased to form a shoulder. The outer diameter of the shoulder is larger than the outer diameter of the rest of the rotating shaft 31. In other words, the outer diameter of the cavity region 3c is larger than the outer diameter of the shaft hole 33a. When the angular velocity of the rotating shaft 31 is constant, the linear velocity of the part of the rotating shaft 31 located in the cavity region 3c is greater, which further increases the flow velocity of the fluid in the cavity region 3c and improves the scouring effect.

[0061] For example, viewed from the second axial end of the circumferential housing 32, the helical groove 31a is left-handed when the shaft 31 rotates clockwise. Alternatively, the helical groove 31a is right-handed when the shaft 31 rotates counterclockwise. Thus, by setting the direction of rotation of the helical groove 31a opposite to the direction of rotation of the shaft 31, during the rotation of the shaft 31, the helical groove 31a can generate a thrust along the second axial end on the liquid in the rotation gap 3b. This reduces the flow of backflowing blood or fluid through the rotation gap 3b to the motor assembly 3, effectively ensuring that backflowing blood or fluid does not enter the interior of the circumferential housing 32, improving structural reliability and extending the service life of the motor assembly 3.

[0062] The arrangement of the flow channel 3a is not limited. For example, the outlet of the flow channel 3a can be located on the flow guide 33 or on the rotating shaft 31.

[0063] In one embodiment, please refer to Figure 6 to Figure 7The rotating shaft 31 is at least partially hollow and defines a portion of the flow channel 3a. A through-hole 31b is provided at the portion of the rotating shaft 31 that defines the cavity region 3c, through which fluid in the flow channel 3a flows to the cavity region 3c. In other words, the outlet of the flow channel 3a is located on the rotating shaft 31, and the hollow structure within the rotating shaft 31 forms a portion of the flow channel 3a near its outlet. Thus, the flow channel 3a does not require occupying circumferential space outside the blood pump rotating shaft 31, meaning the blood pump does not occupy a large amount of space within the patient's body, resulting in a compact arrangement. Furthermore, the flow channel 3a is separated from the drive unit within the circumferential housing by the rotating shaft 31. In this embodiment, by externally transmitting fluid to the cavity region 3c, heat dissipation of the motor assembly 3 is accelerated, extending the service life of the motor assembly 3.

[0064] It is understood that blood pumps can provide cardiac support during interventional procedures or other interventions, or provide support for a longer period after surgery. This embodiment, by placing the flow channel 3a within the blood pump, reduces the burden on the patient's chest region from the heavy and bulky blood pump, thus simplifying blood pump placement.

[0065] For example, please refer to Figure 9 to Figure 10 The through hole 31b can be a tapered hole or a circular hole. For example, if the through hole 31b is a tapered hole, that is, the part of the rotating shaft 31 used to define the cavity region 3c is in a plane perpendicular to the axial direction of the blood pump, and the diameter of the through hole 31b decreases radially outward. Or, if the through hole 31b is a circular hole, that is, the part of the rotating shaft 31 used to define the cavity region 3c is in a plane perpendicular to the axial direction of the blood pump, and the diameter of the through hole 31b is equal radially outward.

[0066] For example, the through hole 31b can be provided on the groove wall of the spiral groove 31a and evenly distributed along the spiral line to accelerate the flow of fluid out of the through hole 31b.

[0067] In another embodiment, please refer to Figure 1 to Figure 3 The motor assembly 3 includes a fluid conduit 35 for inputting fluid. The fluid conduit 35 is disposed on the outer surface of the circumferential housing 32 and extends from a first axial end to a second axial end of the circumferential housing 32. The space within the fluid conduit 35 defines a portion of a flow channel 3a, and the end of the fluid conduit 35 communicates with the cavity region 3c. That is, the outlet of the flow channel 3a is located on the flow guide shroud 33 or the circumferential housing 32, and the end of the fluid conduit 35 forms the outlet of the flow channel 3a. In this embodiment, by arranging the flow channel 3a outside the circumferential housing 32, heat dissipation is accelerated, and the service life of the motor assembly 3 is extended.

[0068] It should be noted that the outer surface of the fluid tube 35 can be sealed to reduce leakage or detachment of the fluid tube 35 during the operation of the blood pump. For example, the sealing treatment can be an adhesive seal.

[0069] It should be noted that in the embodiments of this application, the drive unit and the rotating shaft 31 of the motor assembly 3 can be brushed motors, which have a simple structure, long development time and mature technology, thus reducing the research cost of the motor assembly 3.

[0070] It is understood that the blood pump of this application may not have a hollow structure on the rotating shaft 31, and may form a flow channel 3a through the fluid pipe 35; or, may not have a fluid pipe 35, and may form a flow channel 3a only through the hollow structure of the rotating shaft 31; or may have both a hollow structure on the fluid pipe 35 and the hollow structure on the rotating shaft 31 to form multiple flow channels 3a, thereby accelerating the flushing rate.

[0071] In one embodiment, please refer to Figure 1 and Figure 5 The sidewall of the flow guide shroud 33 has a connection port 33b, and the outlet end of the fluid pipe 35 is connected to the connection port 33b. In this way, the fluid in the fluid pipe 35 can flow into the flow guide shroud 33 through the connection port 33b, and then into the cavity region 3c. Compared to brushless motors in related technologies, this embodiment arranges the flow channel 3a outside the circumferential housing 32, and transmits fluid to the cavity region 3c externally, reducing heat generation in the motor assembly 3 and extending the service life of the motor assembly 3.

[0072] The connection method between the outlet end of the fluid pipe 35 and the connection port 33b is not limited. For example, it can be an adhesive bonding or integral injection molding connection, etc.

[0073] In one embodiment, please refer to Figure 5 There are multiple fluid pipes 35, and multiple connection ports 33b are formed on the side wall of the flow guide shroud 33. Each connection port 33b corresponds to a fluid pipe 35, and the multiple connection ports 33b are arranged at intervals along the circumference of the flow guide shroud 33. In this way, the flow rate of fluid entering the cavity region 3c can be increased by connecting multiple fluid pipes 35, thereby improving the flushing effect on the cavity region 3c.

[0074] It should be noted that in the embodiments of this application, "multiple" refers to no fewer than two.

[0075] In one embodiment, please refer to Figure 2 to Figure 3 or Figure 6 to Figure 7 A second gap 3d is defined between the end faces of the first seal 34 and the flow guide 33 facing each other, and a portion of the fluid in the cavity region 3c flows out from the second gap 3d. That is, by rotating the shaft 31, a portion of the fluid flows axially along the shaft 31 into the second gap 3d formed by the first seal 34 and the flow guide 33. In this way, blood flowing into the second gap 3d through the rotation gap 3b and the cavity region 3c can be flushed out, reducing clotting.

[0076] In one embodiment, please refer to Figure 2 to Figure 3 or Figure 6 to Figure 7The flow guide shroud 33 is located axially outside the circumferential outer shell 32. The end face of the flow guide shroud 33 and the axial end face of the circumferential outer shell 32 are at least partially spaced apart and define a first opening 3e. At least a portion of the fluid in the second gap 3d flows out through the first opening 3e. That is, the end face of the flow guide shroud 33 and the axial end face of the circumferential outer shell 32 are at least partially clearance-fitted, forming the first opening 3e. After the fluid flows into the second gap 3d from the cavity region 3c and flushes it, it flows out through the first opening 3e. This reduces the phenomenon of fluid and blood mixtures remaining in the second gap 3d and being difficult to drain, while the fluid flowing out of the first opening 3e can flush the support column 21, improving the flushing effect.

[0077] The connection relationship between the pump housing 2 and the flow guide 33 is not limited. For example, the pump housing 2 and the flow guide 33 are not connected, and the flow guide 33 is disposed on the circumferential housing, which is connected to the pump housing 2. Another example is that the pump housing 2 and the flow guide 33 are connected, and the connection method between the pump housing 2 and the flow guide 33 is not limited; it can be integrally formed or detachably connected, etc.

[0078] In one embodiment, please refer to Figure 4 and Figure 5 The pump housing 2 has a support column 21, and the outer circumferential surface of the flow guide shroud 33 has a groove 33c. The support column 21 is inserted into the groove 33c, and a third gap b is formed between the support column 21 and the groove wall of the groove 33c. The third gap b is connected to the second gap 3d, and at least a portion of the fluid in the second gap 3d flows to the first gap a through the third gap b. That is, after the support column 21 is inserted into the groove 33c, there is a gap between the support column 21 and the groove wall of the groove 33c. After the fluid flows from the cavity region 3c into the second gap 3d to flush it, a portion of the fluid flows through the second gap 3d into the third gap b, and then through the outer circumferential surface of the flow guide shroud 33 into the first gap a, and flows out from the outlet 2b. In this way, the third gap b formed between the support column 21 and the groove wall of the groove 33c is flushed, reducing the phenomenon of blood clotting.

[0079] For example, the groove 33c of the flow guide shroud 33 can be an arc groove, which reduces the flow resistance of the fluid in the third gap b and improves the flushing efficiency of the fluid.

[0080] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A blood pump, characterized in that, The utility model relates to a blood pump, comprising: a pump housing for pumping blood, the pump housing having an inlet and an outlet; a motor assembly having a shaft, the shaft being connected to the impeller to drive blood in the pump housing from the inlet to the outlet; the motor assembly having a first gap between an end of the motor assembly facing the side where the impeller is located and an axial end surface of the impeller; the motor assembly having a flow channel, an inlet of the flow channel being configured to introduce an external fluid, an outlet of the flow channel being in communication with the first gap to direct at least part of the fluid in the flow channel to the first gap; the motor assembly comprising a circumferential housing and a flow guide cover, the flow guide cover being arranged at one end of the circumferential housing close to the impeller, the motor assembly comprising a first seal arranged inside an axial second end of the circumferential housing and sealing the second end of the circumferential housing, the flow guide cover being arranged at a side of the first seal facing the impeller, the flow guide cover, the first seal and a circumferential surface of the shaft together defining a cavity region; a second gap being defined between end surfaces of the first seal and the flow guide cover facing each other, part of the fluid in the cavity region flowing out of the second gap. the flow guide cover having a shaft hole through which the shaft passes, the flow guide cover and the axial end surface of the impeller forming the first gap, a rotating gap being formed between a circumferential outer surface of the shaft and a hole wall of the shaft hole, the rotating gap constituting at least one of the outlets of the flow channel.

2. The blood pump of claim 1, wherein, the fluid in the flow channel flowing to the rotating gap through the cavity region.

3. The blood pump of claim 2, wherein, an outer wall of a part of the shaft defining the cavity region having a helical groove extending in an axial direction.

4. The blood pump of claim 3, wherein, the motor assembly comprising a fluid tube for inputting fluid, the fluid tube being arranged on an outer surface of the circumferential housing and extending from an axial first end of the circumferential housing to an axial second end of the circumferential housing, a space in the fluid tube defining a part of the flow channel, a terminal end of the fluid tube being in communication with the cavity region.

5. The blood pump of claim 3, wherein, the side wall of the flow guide cover having a connecting port, the outlet end of the fluid tube being connected to the connecting port.

6. The blood pump of claim 5, wherein, there are a plurality of the fluid tubes, the side wall of the flow guide cover having a plurality of the connecting ports, each of the connecting ports corresponding to one of the fluid tubes, wherein the plurality of the connecting ports are arranged at intervals in a circumferential direction of the flow guide cover.

7. The blood pump of claim 6, wherein, the flow guide cover being located outside the circumferential housing in an axial direction, an end surface of the flow guide cover and an axial end surface of the circumferential housing being at least partially spaced apart and defining a first port, at least part of the fluid in the second gap flowing out of the first port.

8. The blood pump of claim 1, wherein, the pump housing having a support, a circumferential outer surface of the flow guide cover having a clamping groove, the support being inserted into the clamping groove, a third gap being formed between the support and a groove wall of the clamping groove, the third gap being in communication with the second gap, at least part of the fluid in the second gap flowing to the first gap through the third gap.

9. The blood pump of claim 1, wherein, ​ 10. The blood pump of any of claims 3-9, wherein, The rotating shaft is at least partially hollow and defines a part of the flow channel, and a through hole is arranged at a position of the rotating shaft for defining the cavity region, and the fluid in the flow channel flows to the cavity region through the through hole.

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