Blood pumping motor, blood pumping device, pumping motor, and power output shaft

Abstract

Disclosed in the present application are a blood pumping motor, a blood pumping device, a pumping motor, and a power output shaft. The blood pumping motor comprises a rotor assembly, and the rotor assembly comprises the power output shaft. The hardness of the power output shaft is greater than or equal to 45 HRC, and the bending stiffness of the power output shaft is greater than or equal to 2100 N·mm2. The power output shaft of the present application is not easy to deform and bend in a continuous high-speed operation state, thereby improving the reliability of the blood pumping motor and the blood pumping device.

Description

Blood pumping motor, blood pumping device, pumping motor and power output shaft

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202411282308.X, filed on September 12, 2024, entitled “Blood pumping motor, blood pumping device, pumping motor and power output shaft”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application belongs to the technical field of medical devices, and in particular relates to a blood pumping motor, a blood pumping device, a pumping motor and a power output shaft. BACKGROUND

[0004] In cardiac surgery, due to the patient's own disease or the need for surgery, the patient's heart function is weakened, and the blood pumping capacity is insufficient. At this time, active intervention medical devices such as ventricular assist devices need to be inserted into the heart to assist the heart in pumping blood. The existing ventricular assist device uses the principle of heart pumping to pump blood out of the heart through a blood pumping motor and guide the blood to the aorta outside the heart to flow to the whole body.

[0005] In some scenarios, in the existing ventricular assist device, the blood pumping device can be inserted through the femoral artery or the axillary artery or the carotid artery. The blood pumping device is gradually miniaturized in modern medical equipment, and in medical scenarios, the blood pumping device requires stable and fault-free operation. In addition, the blood pumping motor of the blood pumping device tends to be miniaturized, providing higher requirements for the performance of the blood pumping motor. The blood pumping motor has contact with blood during application, and it is required that when the components of the blood pumping motor contact the blood, they can still ensure stable and fault-free operation. In related technologies, when the motor operates in blood medium, the rotor drives the impeller to rotate at high speed. Due to the pumping force and the counteracting force, the components in the blood pumping motor deform and are prone to wear, which causes the blood pumping motor to operate poorly or fail prematurely. Therefore, improvement is needed. SUMMARY

[0006] The embodiments of the present application provide a blood pumping motor for a blood pumping device, which can operate stably and fault-free in a working state, especially the power output shaft, which is not prone to deformation and bending in a continuous high-speed running state, thereby improving the reliability of the blood pumping motor. The embodiments of the present application also provide a blood pumping device, a pumping motor and a power output shaft, which at least have the same beneficial effects as the blood pumping motor.

[0007] In a first aspect, embodiments of the present application provide a blood pumping motor for pumping blood, the blood pumping motor comprising a rotor assembly, the rotor assembly comprising a power output shaft, wherein a hardness range of the power output shaft is greater than or equal to 45HRC, and a bending stiffness range of the power output shaft is greater than or equal to 2100N·mm 2 .

[0008] According to embodiments of an aspect of the present application, the bending stiffness range of the power output shaft is 2260N·mm 2 to 4800N·mm 2 .

[0009] According to embodiments of an aspect of the present application, the hardness range of the power output shaft is 55HRC to 65HRC.

[0010] According to embodiments of an aspect of the present application, the power output shaft is cylindrical, and a diameter range of the power output shaft is 0.3mm to 1.5mm.

[0011] According to embodiments of an aspect of the present application, a cross-sectional shape of the power output shaft is N-gon, N is a positive integer, and N is greater than or equal to 6, and an outer diameter range of the power output shaft is 0.3mm to 1.5mm.

[0012] According to embodiments of an aspect of the present application, a length range of the power output shaft is 5mm to 30mm.

[0013] According to embodiments of an aspect of the present application, the power output shaft is cylindrical, and a diameter range of the power output shaft is 0.6mm to 1.0mm.

[0014] According to embodiments of an aspect of the present application, a cross-sectional shape of the power output shaft is N-gon, N is a positive integer, and N is greater than or equal to 6, and an outer diameter range of the power output shaft is 0.6mm to 1.0mm.

[0015] According to embodiments of an aspect of the present application, a length range of the power output shaft is 15mm to 25mm.

[0016] According to embodiments of an aspect of the present application, the blood pumping motor further comprises:

[0017] a distal end bearing, the distal end bearing being sleeved on the power output shaft;

[0018] a proximal end bearing, the proximal end bearing being sleeved on the power output shaft, and the proximal end bearing being located on a proximal end side of the distal end bearing;

[0019] a vane, the power output shaft being rigidly connected with the vane, and the vane being arranged on a side of the distal end bearing away from the proximal end bearing.

[0020] According to an embodiment of the aspect of the application, the impeller is arranged at the distal end of the power output shaft, the length of the power output shaft between the impeller and the distal end bearing is a, the total length of the power output shaft is b, and the length of the power output shaft satisfies a:b = 1:(2-10). That is, in the application, the impeller pumping blood force and the reaction force are generated at the overhanging position of the distal end bearing.

[0021] According to an embodiment of the aspect of the application, the speed range of the power output shaft of the blood pumping motor in the working state is 20000-50000 r / min.

[0022] According to an embodiment of the aspect of the application, the bending stiffness of the distal end bearing is greater than or equal to the bending stiffness of the power output shaft.

[0023] According to an embodiment of the aspect of the application, the bending stiffness of the proximal end bearing is greater than or equal to the bending stiffness of the power output shaft.

[0024] According to an embodiment of the aspect of the application, the hardness of the power output shaft is less than or equal to the hardness of the distal end bearing and the proximal end bearing, respectively.

[0025] According to an embodiment of the aspect of the application, the rotor assembly further comprises a magnetic steel, the magnetic steel is sleeved on the power output shaft, and the blood pumping motor further comprises:

[0026] A stator assembly, the stator assembly comprises a core, the core encloses a containing cavity; at least part of the power output shaft and the magnetic steel are located in the containing cavity;

[0027] A distal end cover connected to the distal end of the stator assembly, the distal end cover is provided with a first through hole penetrating the distal end cover along the length direction of the power output shaft, at least part of the power output shaft extends out of the containing cavity from the first through hole, and at least the first through hole and the power output shaft have a gap.

[0028] According to an embodiment of the aspect of the application, a flow-through cavity is arranged in the blood pumping motor, the flow-through cavity is used for the flow-through of perfusion liquid, and the perfusion liquid contacts the power output shaft when flowing through the flow-through cavity.

[0029] According to an embodiment of the aspect of the application, the material of the power output shaft comprises any one of high nitrogen steel, non-magnetic tungsten steel and martensitic stainless steel.

[0030] According to an embodiment of the aspect of the application, the preparation method of the power output shaft comprises:

[0031] Processing a high-nitrogen steel plate raw material to obtain a predetermined power output shaft shape to obtain a first shaft, wherein the high-nitrogen steel plate raw material comprises the following chemical elements in percentage by mass: C: 0.25% to 0.35%, Si≤1.0%, Mn≤1.0%, P≤0.020%, Cr: 14% to 16%, Ni≤0.5%, Mo: 0.85% to 1.1%, N: 0.3% to 0.5%, and the balance of Fe and other inevitable impurities;

[0032] Processing the first shaft in sequence with first heat treatment and finishing to obtain a power output shaft;

[0033] The first heat treatment comprises heating treatment, quenching treatment, deep cooling treatment and tempering treatment in sequence; the heating treatment comprises heating to 1010°C to 1060°C under a vacuum degree of ≤15 Pa; the deep cooling treatment comprises dropping from room temperature to -80°C to -120°C within 15 min to 45 min, and rising to 20°C to 30°C at a rate of ≤5°C / min; and the target temperature of the tempering is 160°C to 220°C.

[0034] According to an embodiment of one aspect of the present application, the quenching treatment comprises oil quenching with oil at a temperature of 25°C to 50°C.

[0035] According to an embodiment of one aspect of the present application, the quenching treatment comprises oil quenching with oil at a temperature of 25°C to 50°C, followed by flushing with a protective gas at 0.35 MPa to 0.8 MPa.

[0036] According to an embodiment of one aspect of the present application, the quenching treatment comprises gas quenching by flushing with nitrogen at 0.35 MPa to 0.8 MPa.

[0037] According to an embodiment of one aspect of the present application, the method for preparing a power output shaft comprises:

[0038] Mixing and compacting 75% to 94% tungsten carbide and 6% to 25% nickel in percentage by mass to obtain a compacted blank;

[0039] Sintering the compacted blank in a protective atmosphere at a pressure of 4 MPa to 10 MPa to obtain a first blank;

[0040] Rough machining and finishing the first blank to obtain a power output shaft, wherein before or after the rough machining, the method further comprises second heat treatment; the second heat treatment comprises heat preservation at a temperature of 450°C to 650°C for 60 min to 120 min.

[0041] According to an embodiment of one aspect of the present application, the method for preparing a power output shaft comprises:

[0042] The Cr13 type martensitic stainless steel is coarsely processed to obtain a predetermined power output shaft shape to obtain a second shaft;

[0043] The second shaft is sequentially subjected to third heat treatment and finishing to obtain a third shaft;

[0044] The third shaft is subjected to passivation treatment to obtain a power output shaft;

[0045] The passivation treatment includes primary passivation, consolidation passivation and strengthening passivation; the passivation agent for the primary passivation is an environmentally-friendly passivation liquid without chromium acid, the environmentally-friendly passivation liquid includes citric acid, a cyclic cationic surfactant, an inhibitor, and deionized water; the consolidation passivation uses an environmentally-friendly complexing agent; the strengthening passivation uses a chromium-free passivation agent, the chromium-free passivation agent includes a metal chelating agent and a surfactant.

[0046] According to an embodiment of one aspect of the present application, the third heat treatment includes: quenching when the temperature of the second shaft is 950-1030℃, followed by holding for 60-120min; the target temperature of tempering is 400-600℃; the holding time of tempering is 30-120min.

[0047] According to an embodiment of one aspect of the present application, the wear resistance of the power output shaft satisfies: under the rated working condition of the blood pumping motor, the outer diameter of the power output shaft is reduced by not more than 1% after 10 days of continuous rated operation.

[0048] In a second aspect, the embodiments of the present application provide a blood pumping device, which comprises a distal blood flow channel assembly, an interventional sheath assembly and the blood pumping motor of the first aspect connected in sequence.

[0049] In a third aspect, the embodiments of the present application provide a pumping motor for pumping fluid, which comprises:

[0050] The rotor assembly comprises a power output shaft, wherein the hardness of the power output shaft is greater than or equal to 45HRC; the bending stiffness of the power output shaft is greater than or equal to 2100N·mm 2 .

[0051] In a fourth aspect, the embodiments of the present application provide a power output shaft for the blood pumping motor of the first aspect, wherein the hardness of the power output shaft is greater than or equal to 45HRC; the bending stiffness of the power output shaft is greater than or equal to 2100N·mm 2 .

[0052] The blood pumping motor of the embodiment of the present application, when pumping blood in a working state, the power output shaft is in a continuous high-speed rotating state, the power output shaft bears the blood pumping force and the counterforce from the impeller, the rotating centrifugal force of the rotor assembly, the rotor unbalance force, etc., and these loads are easy to cause the power output shaft to deform and wear, leading to poor operation or premature failure of the blood pumping device. Therefore, the hardness of the power output shaft is greater than or equal to 45HRC, which can improve the wear resistance of the power output shaft. The bending stiffness of the power output shaft is greater than or equal to 2100N·mm 2 , which can better bear mechanical load and comprehensively ensure that the power output shaft can stably and continuously rotate at high speed, thereby improving the operation reliability of the blood pumping motor, and meeting the biocompatibility requirements of the blood pumping motor in the body and reducing the risk of thrombus formation and other abnormalities during blood pumping.

[0053] In addition, part of the power output shaft will be in contact with blood, and the material of the power output shaft needs to meet the biological safety requirements of interventional medical devices. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments of the present application will be briefly introduced below. Those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0055] Figure 1 shows a structural schematic diagram of a blood pumping device containing a blood pumping motor according to some embodiments of the present application;

[0056] Figure 2 shows a perspective view of an outflow channel, an interventional sheath assembly and a blood pumping motor according to some other embodiments of the present application;

[0057] Figure 3(a) shows a longitudinal sectional view of an outflow channel, an interventional sheath assembly and a blood pumping motor according to some embodiments of the present application;

[0058] Figure 3(b) shows a longitudinal sectional view of an outflow channel, an interventional sheath assembly and a blood pumping motor according to some embodiments of the present application, in which the cantilever length and the total length in some application scenarios are shown;

[0059] Figure 4 shows a schematic diagram of a three-point bending test for measuring the bending stiffness of a power output shaft;

[0060] Figure 5 shows a curve diagram of displacement and force in a three-point bending test of a power output shaft made of SUS316L material;

[0061] Figure 6 shows a curve diagram of displacement and force in a three-point bending test of a power output shaft made of high-nitrogen steel material;

[0062] Figure 7 shows a curve diagram of displacement and force in a three-point bending test of a power output shaft made of non-magnetic tungsten steel material;

[0063] Figure 8 shows a curve of displacement and force in a three-point bending test of a power output shaft made of a martensitic stainless steel.

[0064] Brief Description of the Drawings The following drawings form part of the present specification and are included to further teach the details of the present application. For a better understanding, the detailed description of the embodiments of the application will be read and understood with reference to the accompanying drawings, in which: DETAILED DESCRIPTION

[0065] Various features and exemplary embodiments of aspects of the present application will be described in detail below with reference to the drawings. The following description is made in connection with the preferred embodiments of the application, but those skilled in the art will recognize that the application is not limited to any particular embodiment. In the following description, numerous details are set forth to provide a complete understanding of the present application. However, one skilled in the relevant art will recognize that the application can be practiced without all of the details given herewith. The following description is merely illustrative of the application and should not be taken in a limiting sense.

[0066] It should be noted that the terms "first" and "second" and the like are used merely to distinguish one element from another, and do not require or imply a specific order or sequence of any such elements. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0067] In the description of embodiments of the present application, the terms "a plurality of" and "a plurality of" refer to two or more (including two), and by analogy, "a plurality of" refers to two or more (including two).

[0068] To solve the technical problems involved in the background art, the applicant proposes a blood pumping device for pumping blood, the blood pumping device comprising a blood pumping motor, the blood pumping motor comprising a rotor assembly, the rotor assembly comprising a power output shaft, wherein the hardness of the power output shaft is greater than or equal to 45HRC; the bending stiffness of the power output shaft is greater than or equal to 2100N·mm 2 .

[0069] The blood pumping device of the embodiment of the application, when pumping blood in the working state, the impeller is in contact with the blood, and an acting force within a certain range is formed on the power output shaft; the power output shaft can be in contact with the blood and respond to the operation of the power output shaft. At the same time, the power output shaft is supported by the bearing, the impeller is rigidly connected with the power output shaft, and the rotor assembly containing the power output shaft drives the impeller to rotate at high speed to pump blood in the working state, which is easy to cause deformation and wear of the power output shaft, resulting in poor operation or premature failure of the blood pumping device. Therefore, increasing the hardness of the power output shaft to be greater than or equal to 45HRC and the bending stiffness of the power output shaft to be greater than or equal to 2100N·mm 2 , can improve the wear resistance and stiffness of the power output shaft, and further improve the biocompatibility of the power output shaft, thereby improving the service life and stability of the blood pumping device. When the bending stiffness of the power output shaft is in the above range, the power output shaft can better bear mechanical load, reduce deformation caused by external force, and reduce the risk of fatigue fracture, thereby ensuring efficient and reliable operation of the blood pumping device.

[0070] Before describing the specific structure of the blood pumping device, a ventricular assist device comprising the blood pumping device will be briefly described in combination with the drawings, so as to understand the working environment of the blood pumping device. It can be understood that, in the present application, the distal end refers to the end facing or close to the operator or physician. The proximal end refers to the end facing the patient and away from the operator or physician. The proximal side refers to a component closer to the proximal end relative to another component, and the distal side refers to a component closer to the distal end relative to another component.

[0071] The technical solutions of the present application will be described below taking one of the ventricular assist devices as an example. It can be understood that other forms of ventricular assist devices are also within the protection scope of the present application, and the present application does not make a one-by-one elaboration on this. FIG. 1 is a structural schematic diagram of a blood pumping device 1 (interventional in-vivo part) comprising a blood pumping motor 10 according to an embodiment of the present application. FIG. 2 is a structural schematic diagram of a blood pumping motor comprising an outflow channel 23 and an interventional sheath assembly 30 according to another embodiment of the present application. FIG. 3(a) shows a longitudinal cross-sectional structural schematic diagram of the blood pumping motor in FIG. 2 as an example.

[0072] As shown in FIG. 1, the ventricular assist device includes a blood pumping device 1, a controller (not shown), and a line assembly (not shown) for connecting the blood pumping device 1 and the controller. The controller is one of the core components of the ventricular assist device, which can monitor and control the operation of the device to ensure that the device works in the expected manner. The blood pumping device 1 and the controller can be electrically connected, signal connected, drivingly connected, or at least one of them can be used to build a perfusion path through the line assembly.

[0073] In some embodiments, the controller includes the following key parts, such as a microprocessor and a software program embedded in the microprocessor, a power management module, a sensor interface, a user interface, a data communication module, etc. The microprocessor executes programs for regulating pump speed, monitoring system status, and performing fault detection. The microprocessor can make decisions based on sensor input data such as flow, pressure, and rotational speed to ensure that the working state of the pump meets the preset parameters. The power management module can include a battery, a power converter, a charging circuit, and a power monitoring system to ensure that the controller and the pump can obtain sufficient power under various working conditions; it can also be responsible for monitoring the battery status (such as power, temperature) and switching to a backup battery or issuing a low power warning when needed. The sensor interface can include flow sensors, pressure sensors, speed sensors, and temperature sensors, etc., to collect data from the pump and other parts of the body, monitor the operating conditions of the pump (such as flow, pressure, speed, and temperature, etc.), and send these data to the microprocessor for analysis and processing to control the operation of the blood pumping device in real time.

[0074] The specific structure of the blood pumping device in one of the ventricular assist devices will be described in detail below with reference to FIGS. 1-3, taking a left heart product as an example. It can be understood that the ventricular assist device involved in the present application can also be applicable to other application scenarios, and its working principle is similar to that of the left heart product, which will not be described here.

[0075] In some embodiments of the present application, as shown in FIG. 1, the blood pumping device 1 includes a distal blood flow passage assembly 20, a blood pumping motor 10, and an intervention sheath assembly 30 connected in sequence from the distal end to the proximal end. The distal blood flow passage assembly 20 forms a blood flow passage (not labeled), and the blood flow passage is provided with an intake window 211 at the distal end and an outflow window 231 at the proximal end. Under the drive of the blood pumping motor 10, blood can enter the blood flow passage from the intake window 211 and be discharged from the outflow window 231. The intervention sheath assembly 30 is used to connect the in-vivo part and the in-vitro part of the blood pumping device 1.

[0076] In some application scenarios, the blood pumping motor 10 of the blood pumping device 1 is located in the body, i.e., in-vivo driving. Exemplarily, the power output shaft of the blood pumping motor 10 can be located in the human body or in the animal body, etc.

[0077] As shown in FIG. 1, the distal blood flow channel assembly 20 includes, in sequence from distal to proximal, an intake channel 21, a transvalvular elbow 22, and an outflow channel 23, which form a blood flow channel inside. The intake channel 21 is provided with an intake window 211 that communicates between the inside and outside of the intake channel 21, and the outflow channel 23 is provided with an outflow window 231 that communicates between the inside and outside of the outflow channel 23. The intake window 211 communicates with the outflow window 231 through the blood flow channel.

[0078] As shown in FIGS. 2 and 3(a), in one example, the blood pumping motor 10 has one end facing the interventional sheath assembly 30 and the other end facing the outflow channel 23, and the proximal end of the outflow channel 23 is formed with the outflow window 231 in communication with the blood pumping motor 10. When the blood pumping motor 10 is started, the blood pumping motor 10 drives blood into the outflow channel 23 and out of the outflow window 231, thereby achieving the blood pumping function of the ventricular assist device.

[0079] As shown in FIG. 1, in some application scenarios, during blood pumping, blood enters the intake channel 21 through the intake window 211, flows through the transvalvular elbow 22 and the outflow channel 23, and then flows out of the outflow window 231 of the blood pumping device 1. Alternatively, blood enters the outflow channel 23 through the outflow window 231, flows through the transvalvular elbow 22 and the intake channel 21, and then flows out of the intake window 211 of the blood pumping device 1.

[0080] In some optional embodiments, as shown in FIG. 1, the distal blood flow channel assembly 20 further includes a flexible tip piece 24 arranged at the distal end of the intake channel 21. The flexible tip piece 24 is used to prevent the blood pumping device 1 from directly contacting the ventricular wall when pumping blood at high speed, thereby avoiding causing ventricular wall damage.

[0081] Optionally, during the operation, the operator can locate the femoral artery implant site, perform a subcutaneous incision operation on the patient, implant a guide wire (not shown) from the femoral artery through the incision, and guide the guide wire to pass through the abdominal aorta, the thoracic aorta, the aortic arch, cross the aortic valve, and finally enter the left ventricle.

[0082] In some embodiments of the present application, the interventional sheath assembly 30 includes a first accommodating cavity (not shown) in which a perfusion tube (not shown) in communication with the blood pumping motor 10 is arranged, and the perfusion tube is used to deliver perfusion fluid to the blood pumping motor 10. The perfusion fluid can be normal saline, balanced salt solution, heparin anticoagulation glucose solution, etc., and can be used to reduce electrolyte imbalance, thrombosis risk, etc.

[0083] In some embodiments of the present application, the interventional sheath assembly 30 further includes a second accommodating cavity (not shown) in which a drainage tube (not shown) in communication with the blood pumping motor 10 is arranged, and the drainage tube is used to drain waste liquid in the blood pumping motor 10.

[0084] In some implementations, the interventional sheath assembly 30 can be a hollow tubular structure, including a proximal end (corresponding to the distal end) connected to the blood pumping motor 10 and a distal end (corresponding to the proximal end). In use, the blood pumping device 1 is inserted into the heart of a patient through a blood vessel such as the femoral artery, axillary artery, carotid artery, femoral vein, etc. via the interventional sheath assembly 30 and realizes the blood pumping function. The distal end of the interventional sheath assembly 30 extends out of the patient's body and is connected to other extracorporeal equipment. The interventional sheath assembly 30 is a soft catheter to adapt to the shape of the aorta, especially the aortic arch when extending into the blood vessel. In the interventional state, the end of the interventional sheath assembly 30 away from the blood pumping motor 10 extends out of the patient's body and is connected to a liquid storage tank (not shown). The blood pumping motor 10 is connected to power supply equipment, controllers and other equipment to realize blood pumping.

[0085] It can be understood that the above-mentioned blood pumping device 1 is only one of the implementations of the blood pumping device to which the power output shaft is applied in the present application, and other blood pumping devices requiring power output shaft driving are also within the protection scope of the present application, which will not be expanded herein.

[0086] After describing the overall structure of the ventricular assist device, the blood pumping motor 10 provided by one of the embodiments of the present application will be introduced below in combination with the accompanying drawings. In the description, the line extending along the proximal end and the distal end of the blood pumping motor 10 in the drawings, and the direction from the distal end to the proximal end is denoted as x. In the drawings, the size in the drawings is not necessarily proportional to the actual size for the convenience of drawing.

[0087] As shown in FIG. 3(a), in the present application, the blood pumping motor 10 includes a stator assembly 11 and a rotor assembly 12. The stator assembly 11 includes an iron core 111 and a winding 112. The iron core 111 encloses a receiving cavity 1111. The rotor assembly 12 includes a power output shaft 121. The power output shaft 121 extends along the x direction, and at least part of the power output shaft 121 is located in the receiving cavity 1111.

[0088] As shown in FIG. 3(a), in some implementations of the present application, the rotor assembly 12 further includes a magnetic steel 122, which is sleeved on the power output shaft 121. The magnetic steel 122 is located in the receiving cavity 1111 and is sleeved on the power output shaft 121. Exemplarily, the winding 112 at least partially surrounds the outside of the magnetic steel 122. The interaction of the permanent magnetic field and the excitation magnetic field of the two makes the magnetic steel 122 and the power output shaft 121 rotate at a high speed.

[0089] In some implementations of the present application, the magnetic steel 122 can be a permanent magnet, and can be a hollow circular ring. The permanent magnet can form a permanent magnetic field. The permanent magnet is usually installed on the power output shaft 121, directly generating a constant magnetic field without the need for external power supply or current. The excitation magnetic field is generated by the excitation current flowing in the excitation winding (usually located in the stator assembly 11) of the blood pumping motor 10. The controller sequentially supplies power to the winding 112 to generate the excitation magnetic field, and the permanent magnetic field of the magnetic steel 122 interacts with the excitation magnetic field of the winding 112 to make the blood pumping motor 10 (i.e., the magnetic steel 122 and the power output shaft 121) rotate at high speed, thereby realizing blood pumping by the blood pumping motor 10.

[0090] Continuing to refer to FIG. 3(a), the blood pumping motor 10 further includes an impeller 19 in the outflow channel 23 and rigidly connected with the power output shaft 121. Based on this, the magnetic steel 122 interacts with the winding 112 to make the magnetic steel 122 and the power output shaft 121 rotate at high speed, thereby completing blood pumping by the impeller 19.

[0091] In some embodiments of the present application, the blood pumping motor 10 includes the power output shaft 121 in the rotor assembly 12, wherein the hardness of the power output shaft 121 is in the range of ≥45HRC; and the bending stiffness of the power output shaft 121 is in the range of ≥2100N·mm 2 In the working state of the blood pumping device 1, at least part of the power output shaft 121 can be in contact with blood. Therefore, when the bending stiffness of the power output shaft 121 is in the above range, the power output shaft 121 can better bear mechanical load, reduce deformation caused by external force, and reduce the risk of fatigue fracture, thereby ensuring efficient and reliable operation of the blood pumping device 1. In addition, the power output shaft 121 can be in contact with blood, and still maintains good wear resistance, corrosion resistance, and biological safety under the condition of being in contact with blood.

[0092] As an example, the hardness of the power output shaft 121 can be the surface hardness of the power output shaft 121.

[0093] It can be understood that the bending stiffness is a measure of the ability of a material to resist bending deformation, also known as bending strength. The greater the bending stiffness, the less likely the material is to bend, and thus the smaller the deformation under the same load; on the contrary, the smaller the bending stiffness, the more likely the material is to bend, and thus the greater the deformation under the same load.

[0094] In some embodiments of the present application, the bending stiffness can be calculated as the product of the area moment of inertia of the cross section to be measured and the elastic modulus of the material used. Through conversion, the bending stiffness = F·L 3F = (48 · δ) / L. Wherein, L represents the support point spacing, unit: mm; F represents the applied force, unit: N; δ represents the deformation, unit: mm; the bending stiffness can be adjusted by the corresponding material selection; the bending stiffness can be adjusted by the corresponding geometric measures, such as changing the cross section to be measured.

[0095] As an example, the detection method of the bending stiffness can be: in the three-point bending experiment, using the universal testing machine according to the schematic diagram of FIG. 4, the support interval L between the two ends of the power output shaft 121 is 8 mm, the force F when a certain deformation δ of 0.4 mm is pressed at the midpoint of the support interval L, for example, F can be 85 N. The cross section of the power output shaft 121 is circular, and the diameter d is 1 mm. For example, when the bending stiffness increases, in this three-point bending experiment, under the premise that other experimental conditions remain unchanged, the force F can be greater than 85 N, such as 90 N, 110 N, etc.

[0096] Optionally, the bending stiffness of the power output shaft 121 can be any value or range composed of any value in 2100 N·mm2, 2200 N·mm2, 2260 N·mm2, 2300 N·mm2, 2400 N·mm2, 2500 N·mm2, 2600 N·mm2, 2700 N·mm2, 2800 N·mm2, 2900 N·mm2, 3000 N·mm2, 3100 N·mm2, 3200 N·mm2, 3300 N·mm2, 3400 N·mm2, 3500 N·mm2, 3600 N·mm2, 3700 N·mm2, 3800 N·mm2, 3900 N·mm2, 4000 N·mm2, 4100 N·mm2, 4200 N·mm2, 4300 N·mm2, 4400 N·mm2, 4500 N·mm2, 4600 N·mm2, 4700 N·mm2, 4800 N·mm2, or a range composed of any value thereof. 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 .

[0097] ​​​​​​​​​​​​​​​​​​Optionally, the hardness of the power output shaft 121 can be any value in the range of 45HRC, 46HRC, 47HRC, 48HRC, 49HRC, 50HRC, 51HRC, 52HRC, 53HRC, 54HRC, 55HRC, 56HRC, 57HRC, 58HRC, 59HRC, 60HRC, 61HRC, 62HRC, 63HRC, 64HRC, 65HRC, or a range composed of any of them. In some optional embodiments, the hardness of the power output shaft 121 ranges from 55HRC to 65HRC.

[0098] It can be understood that the hardness can be detected according to the method commonly used in the art, for example, ISO 6508-1:2016-Metallic materials- Rockwell hardness test Part 1: Test method.

[0099] In some optional embodiments, the power output shaft 121 is cylindrical, and the diameter of the power output shaft 121 ranges from 0.3mm to 1.5mm, optionally from 0.6mm to 1.0mm. Exemplarily, the diameter of the power output shaft 121 can be any value in the range of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, or a range composed of any of them. The diameter of the power output shaft 121 is in the above range, which means that the power output shaft 121 with the diameter meets the bending stiffness and hardness in the high-speed running state, and is beneficial to improve the running stability of the power output shaft 121.

[0100] In some optional embodiments, the length of the power output shaft 121 ranges from 5mm to 30mm, optionally from 15mm to 25mm. Exemplarily, the length of the power output shaft 121 can be any value in the range of 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, 20mm, 25mm, 30mm, or a range composed of any of them. The length of the power output shaft 121 is in the above range, which means that the power output shaft 121 with the length has a smaller deformation amount in the force scenario of the blood pumping motor 10 in the high-speed running state, and is beneficial to improve the running stability of the power output shaft 121.

[0101] In some optional embodiments, the cross-sectional shape of the power output shaft 121 is an N-sided polygon, N is a positive integer, N is greater than or equal to 6, and the outer diameter of the power output shaft 121 ranges from 0.3 mm to 1.5 mm, and can be optionally 0.6 mm to 1.0 mm. Illustratively, the outer diameter of the power output shaft 121 can be any value or range composed of any value in the range of 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm. The outer diameter of the power output shaft 121 is in the above range, which means that the power output shaft 121 with this diameter meets the bending stiffness and hardness in the high-speed operation state, which is beneficial to improve the operation stability of the power output shaft 121.

[0102] It can be understood that when the cross-sectional shape of the power output shaft 121 is an N-sided polygon, the outer diameter can be measured by a coordinate measuring machine (CMM). In some embodiments of the present application, the coordinates of each vertex of the N-sided polygon can be obtained, and then the diameter of the circumscribed circle is determined by calculation, and the diameter is taken as the outer diameter of the N-sided polygon.

[0103] In some optional embodiments, the blood pump motor 10 further comprises: an impeller, the power output shaft 121 is rigidly connected with the impeller, and the impeller is arranged on the side of the distal bearing away from the proximal bearing. The connection between the impeller and the output end of the power output shaft 121 can be bonding or insert injection molding. The power output shaft 121 can pass through the inner diameter of the permanent magnet magnetic steel 122 and be fixed as a whole. By using the above-mentioned connection between the power output shaft 121 and the impeller, deformation during operation can be avoided, the coaxiality of the power output shaft 121 and the axis of the micro motor during operation can be improved, the probability of hemolysis can be reduced, the impeller and the pump shell can be avoided from scratching, the components can be avoided from wearing, the probability of poor operation or premature failure of the blood pump motor 10 can be reduced, and the stability of the blood pump motor 10 can be improved.

[0104] In some examples, a first flow channel and a second flow channel are arranged on the circumferential side of the power output shaft 121, the first flow channel communicates the first flow cavity 1112 with the containing cavity 1111, and the second flow channel communicates the second flow cavity 1113 with the second pipeline, for the flow of perfusion fluid, and contacts the power output shaft 121 in the perfusion fluid flow path.

[0105] Continuing to refer to FIG. 3(a), in some embodiments of the present application, the blood-pumping motor 10 further comprises a distal bearing 13 and a proximal bearing 14. The distal bearing 13 and the proximal bearing 14 are arranged on the power output shaft 121, and the proximal bearing 14 is located on the proximal side of the distal bearing 13. The first flow-through cavity 1112 is directly or indirectly communicated with the containing cavity 1111 through the distal bearing 13, and the second flow-through cavity 1113 is directly or indirectly communicated with the second conduit through the proximal bearing 14. That is, the distal bearing 13 and the distal bearing seat 18 form a first flow-through passage, and the proximal bearing 14 and the proximal bearing seat 17 form a second flow-through passage.

[0106] In some implementations, the distal bearing 13 and the proximal bearing 14 are ball bearings. The distal bearing 13 and the proximal bearing 14 are provided with gaps through which the perfusion liquid can pass. For example, the gaps between the balls and the balls, and the perfusion liquid located on both sides of the bearing in the axial direction can flow through the gaps on the bearing. In alternative implementations, the distal bearing 13 and the proximal bearing 14 are sliding bearings, and the distal bearing 13 and other components (such as a bearing seat) are formed with gaps allowing the perfusion liquid to pass through, and the proximal bearing 14 and other components (such as a bearing seat) are formed with gaps allowing the perfusion liquid to pass through. The perfusion liquid located on both sides of the bearing in the axial direction can flow through the above-mentioned gaps. In alternative implementations, one of the distal bearing 13 and the proximal bearing 14 is a ball bearing, and the other is a sliding bearing, which can be a combination of the first two implementations.

[0107] Generally speaking, a material with high bending stiffness is more difficult to deform than a material with low bending stiffness. That is, a material with high bending stiffness deforms less under the same external force, while a material with low bending stiffness deforms more.

[0108] In some optional embodiments, the bending stiffness of the distal bearing 13 is greater than or equal to the bending stiffness of the power output shaft 121. Therefore, the change in the force of the distal bearing 13 acting on the power output shaft 121 is reduced, the supporting effect of the power output shaft 121 is stably achieved, and the stable operation of the power output shaft 121 can be achieved. For example, the power output shaft 121 is made of high-nitrogen steel, martensitic stainless steel, etc.

[0109] In some optional embodiments, the bending stiffness of the proximal bearing 14 is greater than or equal to the bending stiffness of the power output shaft 121. Therefore, the change in the force of the proximal bearing 14 acting on the power output shaft 121 is reduced, the supporting effect of the power output shaft 121 is stably achieved, and the stable operation of the power output shaft 121 can be achieved. For example, the power output shaft 121 is made of high-nitrogen steel, martensitic stainless steel, etc.

[0110] In some optional embodiments, the hardness of the power output shaft 121 is less than or equal to the hardness of the distal bearing and the proximal bearing, respectively.

[0111] Therefore, the hardness of the power output shaft 121 is less than or equal to the hardness of the distal bearing and the proximal bearing respectively, which can reduce the wear of the distal bearing and the proximal bearing respectively, and also ensure that the power output shaft 121 can be stably operated without failure for a long time or within the quality assurance period, and such a combination of hardness design can balance the wear resistance and the stability of the assembly. If necessary, the power output shaft 121 can be replaced after the quality assurance period of the blood pumping device 1, which is relatively simple and cost-effective. For example, the power output shaft 121 made of high-nitrogen steel, martensitic stainless steel, etc.

[0112] In addition, during the operation of the blood pumping motor 10, the power output shaft 121 needs to bear dynamic loads from different directions. The hardness of the power output shaft 121 is relatively lower than the hardness of the distal bearing and the proximal bearing, which makes the shaft better absorb impact loads or vibrations, and the power output shaft 121 has good bending stiffness, which can increase the stability and reliability of the motor. The power output shaft 121 has corresponding contact surfaces with the distal bearing and the proximal bearing respectively, and the wear of the contact surfaces of the power output shaft 121 will be relatively faster. If necessary, a layer of biocompatible lubricating oil film can be coated on the surface of the power output shaft 121 or formed on the surface of the power output shaft 121, thereby reducing the risk of friction and seizure, further ensuring the stable operation of the power output shaft 121, and also improving the service life of the power output shaft 121.

[0113] In summary, the bending stiffness and hardness of the proximal bearing 14, the distal bearing 13 and the power output shaft 121 are set as described above, which can stably support the power output shaft 121 in the working state of the blood pumping motor 10, and improve the operation stability of the blood pumping motor 10 and the blood pumping device 1. In the following, after describing the specific material of the power output shaft 121, the comparison results of the bending stiffness and hardness between the distal bearing 13, the proximal bearing 14 and the power output shaft 121 will be described in detail.

[0114] In some embodiments of the present application, the power output shaft 121 in the blood pumping motor 10 is a cantilever structure, which can be understood as the part of the power output shaft 121 away from the side of the proximal bearing 14 at the distal bearing 13. As shown in FIG. 3(a), the cantilever state of the power output shaft 121 will be described in combination with the length ratio.

[0115] Continuing to refer to FIG. 3(a), in some embodiments of the present application, the distal bearing 13 is sleeved on the proximal end of the power output shaft 121, the proximal bearing 14 is sleeved on the power output shaft 121 and located between the proximal end and the distal end of the power output shaft 121. The impeller 19 is sleeved on the distal end of the power output shaft 121. That is, the power output shaft 121 in the present application is in a cantilevered state. When the blood pumping motor 10 is started, the power output shaft 121 drives the impeller 19 to rotate, and the impeller 19 pumps blood from the suction window 211 to the outflow window 231 when rotating and realizes the blood pumping function. The power output shaft 121 of the present application has a suitable hardness, which improves the wear resistance of the power output shaft 121; the power output shaft 121 of the present application has a suitable bending stiffness, which can effectively resist the moment deviation force and impact of the impeller and blood on the power output shaft 121.

[0116] In addition, the power output shaft 121 is connected with the impeller 19, and when the impeller 19 rotates, part of the blood may be in contact with the power output shaft 121, and the impeller 19 and the blood have a certain force on the power output shaft 121, which affects the stability of the power output shaft 121.

[0117] In some optional embodiments, the length of the power output shaft 121 between the impeller 19 and the distal bearing 13 is a, and the total length of the power output shaft 121 is b, and FIG. 3(b) shows a longitudinal sectional view of the outflow channel, the interventional sheath assembly and the blood pumping motor in some embodiments of the present application, which illustrates the cantilever length and the total length in some application scenarios. Referring to FIG. 3(b), the length a of the power output shaft 121 between the impeller 19 and the distal bearing 13 can be understood as the cantilever length and the total length of the power output shaft 121 satisfying the relationship: a:b = 1:(2 to 10).

[0118] As shown in FIG. 3(b), in some implementations of the present application, the length a of the power output shaft 121 between the impeller 19 and the distal bearing 13 can be measured as follows: taking a virtual point in the impeller 19 for bearing external load as a first midpoint position, and taking the center of the overlapping length of the distal bearing 13 and the power output shaft 121 in the length direction of the power output shaft 121 as a second midpoint position, the axial spacing between the first midpoint position and the second midpoint position is a. Similarly, the total length b of the power output shaft 121 can be measured as follows: taking a virtual point in the impeller 19 for bearing external load as a first midpoint position, and taking the center of the overlapping length of the proximal bearing 14 and the power output shaft 121 in the length direction of the power output shaft 121 as a third midpoint position, the axial spacing between the first midpoint position and the third midpoint position is b.

[0119] It can be understood that the aforementioned first midpoint position can be a position used to represent the actual force of the impeller 19 or a collective position when the impeller is regarded as a point. In some application scenarios, the first midpoint position can be located at a cross section at the axial midpoint of the impeller 19. In other application scenarios, the first midpoint position can be located at the distal end face of the power output shaft 121.

[0120] Optionally, the ratio of a:b can be any value in 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:9, 1:10 or a range composed of the above values. The application controls the ratio of a:b, controls the support form of the power output shaft 121, that is, controls the length of the power output shaft 121 between the impeller 19 and the distal end bearing 13, which can be understood as the ratio of the length of the cantilever to the entire length of the power output shaft 121, and is beneficial to control the stress moment of the power output shaft 121, so that the power output shaft 121 has appropriate hardness and bending stiffness under the action of the stress moment, realizes stable operation, and reduces the failure probability of the blood pumping motor 10.

[0121] In some optional embodiments, the rotation speed of the power output shaft 121 in the working state of the blood pumping motor 10 ranges from 20,000 rpm to 50,000 rpm.

[0122] Optionally, the rotation speed of the power output shaft 121 can be any value in 20,000 rpm, 25,000 rpm, 30,000 rpm, 35,000 rpm, 40,000 rpm, 45,000 rpm, 50,000 rpm or a range composed of the above values. When the rotation speed of the power output shaft 121 is at the above level, the higher the rotation speed, the greater the wear of the power output shaft 121, and therefore the power output shaft 121 is required to have better wear resistance and be less likely to deform. The hardness of the power output shaft 121 is set to be greater than or equal to 45 HRC, and the bending stiffness of the power output shaft 121 is greater than or equal to 2,100 N·mm 2 , which can realize stable operation of the power output shaft 121 at the above rotation speed, thereby reducing the failure probability of the blood pumping motor 10.

[0123] In the related art, the power output shaft 121 in the blood pumping motor 10 mostly adopts SUS316L, SUS316LVM and the like. These grades generally belong to austenitic stainless steel, which has low hardness, and cold drawing treatment can only increase the hardness to about 28 HRC, resulting in insufficient strength of the power output shaft 121, easy deformation and easy wear, and ultimately leading to poor operation or early failure of the blood pumping motor 10.

[0124] In view of this, the application provides improvements on the power output shaft 121 to solve the above problems.

[0125] In some optional embodiments, the material of the power output shaft 121 includes any one of high-nitrogen steel, non-magnetic tungsten steel, and martensitic stainless steel. The power output shaft 121 made of the above-mentioned materials can meet the hardness and bending stiffness requirements through relevant processes, ensuring that the blood pumping motor 10 works efficiently and reliably in the blood pumping device 1. This is conducive to improving the biocompatibility of the power output shaft 121 and reducing the probability of thrombosis and other occurrences.

[0126] In some optional embodiments, the material of the power output shaft 121 is high-nitrogen steel, and the preparation method of the power output shaft 121 includes steps 100 and 110.

[0127] In step 100, a high-nitrogen steel plate raw material is processed to obtain a predetermined power output shaft 121 shape to obtain a first shaft. The high-nitrogen steel plate raw material includes the following chemical elements in mass percentage: C: 0.25%-0.35%, Si≤1.0%, Mn≤1.0%, P≤0.020%, Cr: 14%-16%, Ni≤0.5%, Mo: 0.85%-1.1%, N: 0.3%-0.5%, and the balance is Fe and other unavoidable impurities.

[0128] In this step, the content of nitrogen element in the high-nitrogen steel plate raw material will affect the hardness and toughness of the material. Subsequent appropriate heat treatment process ensures uniform diffusion and dissolution of nitrogen, avoiding excessive precipitation or segregation of nitrogen, which can optimize the hardness and bending strength of the material.

[0129] In step 110, the first shaft is sequentially subjected to first heat treatment and finishing to obtain the power output shaft 121. The first heat treatment includes heating treatment, quenching treatment, cryogenic treatment, and tempering treatment in sequence. The heating treatment includes heating to 1010-1060℃ for 45-120min under a vacuum degree of ≤15Pa.

[0130] In the heat treatment process, the hardness is mainly controlled by the processes of heating treatment, quenching treatment, and tempering treatment. The material has the highest hardness after quenching, but is more brittle. Through quenching treatment and tempering treatment, the hardness is treated to an appropriate range (e.g., 45-65HRC), while retaining a certain toughness, enhancing the bending stiffness, and reducing the risk of internal stress and deformation.

[0131] In the heat treatment process, the target temperature of heating during quenching is between 1010-1060℃. The above-mentioned steel is rapidly cooled after quenching, usually using oil quenching or gas quenching, to obtain martensite or austenite organization, which can improve the hardness of the material.

[0132] In some optional embodiments, the interval time between the quenching treatment and the deep cooling treatment can be within 0.5 h. Such a setting is conducive to maintaining the stability of the metallurgical structure obtained by the quenching treatment, reducing the transformation of the metallurgical structure, and stabilizing the hardness and other properties of the steel.

[0133] In some optional embodiments, the heating treatment comprises: heating under a vacuum degree of ≤15 Pa, heating to a target temperature of 600-900 °C and holding, continuing to heat to 1010-1060 °C and holding for 45-120 min. The time for heating to a target temperature of 600-900 °C and holding can be 15-60 min, and can be 30 min. The pressure condition, target temperature, and holding time in the heating treatment can improve the internal structure of the steel, so that the bending stiffness can be better improved in the subsequent treatment stage (such as tempering). After quenching, the hardness of the steel increases, and the bending stiffness also increases accordingly.

[0134] In some optional embodiments, the deep cooling treatment comprises: decreasing from room temperature to -80- -120 °C within 15-45 min and continuing to hold for 60-120 min, and then increasing to 20-30 °C at a rate of ≤5 °C / min and holding for 5-30 min. During the deep cooling treatment, the rate of cooling, the target temperature of cooling, the holding time, and the rate of increasing temperature can cause the austenite (a phase at high temperature) to transform into a more stable martensite phase, which can improve the hardness of the material. The deep cooling treatment can help refine the metallurgical structure of the material, reduce large particles of carbides and nitrides, and optimize the phase structure. In high-nitrogen steel, the deep cooling treatment can convert part of the austenite into martensite. Martensite is a phase with extremely high hardness, which can significantly improve the hardness of the steel. The deep cooling treatment can refine the metallurgical structure or grain size of the steel, and reduce the coarse carbide or nitride particles, which helps to improve the hardness and wear resistance. Improving the wear resistance of the power output shaft 121, reducing the release of metal ions, and thus improving the biocompatibility of the power output shaft 121, and reducing the probability of thrombosis and the like. The above deep cooling treatment is more suitable for high-nitrogen steel raw materials, which further ensures the hardness and controls the bending stiffness of the power output shaft 121, and improves the stability of the blood pumping motor 10 in operation.

[0135] In some alternative embodiments, the quenching treatment can use oil quenching at a temperature of 25°C to 50°C; the quenching treatment can also use oil quenching stirring and flushing with a protective gas at a pressure of 0.35 MPa to 0.8 MPa; or the quenching treatment can be achieved by flushing with a protective gas at a pressure of 0.35 MPa to 0.8 MPa. The protective gas can be nitrogen, which can prevent denitrogenation on the surface of the power output shaft 121. In the present embodiment, the nitrogen element plays a role of solid solution strengthening and precipitation strengthening in the high-nitrogen steel, thereby improving the strength and hardness of the steel and the corrosion resistance of the high-nitrogen steel. Improving the corrosion resistance of the power output shaft 121 is also conducive to reducing the release of metal ions, thereby improving the biocompatibility of the power output shaft 121 and reducing the probability of thrombosis and the like.

[0136] In some alternative embodiments, the protective gas can further include inert gases such as argon and helium.

[0137] In some alternative embodiments, the tempering can be performed at a target temperature of 160°C to 220°C for 60 min to 120 min. The tempering can be performed twice. The tempering can be performed using an oil tank or a gas quenching vacuum furnace or a box-type tempering furnace.

[0138] The target temperature and the holding time of the tempering treatment described above can effectively adjust the hardness of the high-nitrogen steel, and can improve the toughness of the material without significantly reducing the strength. Generally, the high-nitrogen steel after quenching usually has very high hardness and brittleness. Through tempering, the brittleness can be reduced, the toughness can be improved, the internal stress generated during quenching can be reduced, and thus the uniformity of the material hardness can be improved. This has a positive effect on the wear resistance and fatigue resistance of the high-nitrogen steel. Too high tempering temperature or too long time can lead to the formation of unfavorable precipitated phases (such as large particles of carbides or nitrides in the ferrite and austenite matrix), which can reduce the toughness and corrosion resistance of the material.

[0139] In some alternative embodiments, a small amount of nitrogen gas is filled during tempering to prevent surface denitrogenation. The nitrogen element plays a role of solid solution strengthening and precipitation strengthening in the high-nitrogen steel, thereby improving the strength and hardness of the steel and the corrosion resistance of the high-nitrogen steel.

[0140] As an example, the main chemical components of the high-nitrogen steel can include C: 0.316%, Cr: 14.5%, Mo: 0.986%, Mn: 0.43%, Si: 0.697%, Ni: 0.207%, the balance being Fe and unavoidable impurity elements, in terms of mass percentage. During preparation, the proportion of the martensite structure is continuously reduced, and the proportion of the austenite structure is continuously increased. During tempering, the proportion of the tempered martensite structure is continuously increased. The finally prepared high-nitrogen steel has a structure of tempered martensite and a small proportion of residual austenite, which can meet the performance requirements of the hardness and bending stiffness of the power output described above.

[0141] In some optional embodiments, the material of the power output shaft 121 is high nitrogen steel, the hardness and rigidity of the power output shaft 121 are less than the hardness and rigidity of the distal bearing 13, and the hardness and rigidity of the power output shaft 121 are less than the hardness and rigidity of the proximal bearing 14.

[0142] In some optional embodiments, the material of the power output shaft 121 is non-magnetic tungsten steel, and the preparation method of the power output shaft 121 comprises steps 200, 210 and 230.

[0143] In step 200, 75% to 94% tungsten carbide and 6% to 25% nickel are mixed and pressed to obtain a pressed plate.

[0144] In this step, tungsten carbide has very high hardness, for example, HV ≈ 2200-2400, which improves the hardness of the composite material. Nickel as a binder can improve the toughness and impact resistance of the composite material. The proportion of nickel affects the ductility and toughness of the material. The above-mentioned content of tungsten carbide and nickel can improve the bending stiffness of the material while not significantly reducing the hardness. In addition, the mixed material can be pressed by a powder metallurgy method, which can reduce porosity and thus improve hardness and bending stiffness.

[0145] In step 210, the pressed plate is sintered in a protective atmosphere at a pressure of 4 MPa to 10 MPa to obtain a first plate.

[0146] In step 230, the first plate is rough machined and finished to obtain the power output shaft 121, wherein before or after the rough machining, the method further comprises a second heat treatment; the second heat treatment comprises: heat preservation at a temperature of 450°C to 650°C for 60 min to 120 min.

[0147] After sintering is completed, subsequent heat treatment such as tempering or aging treatment can be performed to adjust the microstructure. The heat treatment can be heat preservation at a temperature of 450°C to 650°C for 60 min to 120 min. The heat treatment can promote the precipitation strengthening of the nickel-based binder phase, achieve the effects of grain refinement and stress relief; improve the overall hardness, and also enhance the toughness and bending stiffness of the material.

[0148] In some optional embodiments, the material of the power output shaft 121 is non-magnetic tungsten steel, the hardness and rigidity of the power output shaft 121 are greater than the hardness and rigidity of the distal bearing 13, and the hardness and rigidity of the power output shaft 121 are greater than the hardness and rigidity of the proximal bearing 14, which is conducive to improving the biocompatibility of the power output shaft 121 and reducing the probability of thrombosis and the like.

[0149] In some optional embodiments, the power output shaft 121 is made of Cr13 martensitic stainless steel, and the preparation method of the power output shaft 121 comprises steps 300, 310 and 320.

[0150] In step 300, the Cr13 martensitic stainless steel is roughly processed to obtain a predetermined shape of the power output shaft 121, thereby obtaining a second shaft.

[0151] In this step, the Cr13 martensitic stainless steel can be 1Cr13, 2Cr13, 3Cr13, 4Cr13 martensitic stainless steel specified in GB / T 1220-2007 “Stainless Steel Bar”.

[0152] In step 310, the second shaft is sequentially subjected to third heat treatment and finishing, thereby obtaining a third shaft.

[0153] In step 320, the third shaft is subjected to passivation treatment, thereby obtaining the power output shaft 121.

[0154] In some optional embodiments, the passivation treatment comprises primary passivation, consolidation passivation and strengthening passivation; the passivation agent for primary passivation is an environmentally friendly passivation liquid without chromic acid, and the environmentally friendly passivation liquid comprises citric acid, a cyclic cationic surfactant, an inhibitor, and deionized water; the consolidation passivation uses an environmentally friendly complexing agent; and the strengthening passivation uses a chromium-free passivation agent, which comprises a metal chelating agent and a surfactant.

[0155] The above passivation treatment can be oxidized by a strong oxidizing agent or an electrochemical method, so that the surface becomes passive, that is, the process of passivation, which is a method of converting the metal surface into a state that is not easy to be oxidized, protecting the surface by forming a chemical conversion film, and delaying the corrosion rate of the metal. It is beneficial to reduce the release of metal ions, thereby improving the biocompatibility of the power output shaft 121 and reducing the probability of thrombosis.

[0156] In the film layer obtained by passivation treatment, chromium mainly exists in the form of trivalent chromium Cr 3+ and hexavalent chromium Cr 6+ . Trivalent chromium is the skeleton, and hexavalent chromium has a self-repairing effect, so the corrosion resistance is very high. It cannot be derived from Cr13 martensitic stainless steel.

[0157] Before passivation treatment, processes such as finishing and oil removal and degreasing can be performed. For example, oil removal and degreasing can be performed using degreasing agents, oil removal powders, white electrical oil, hydrocarbon solvents, dishwashing liquid, etc. Before and after the above passivation processes, such as primary passivation, consolidation passivation and strengthening passivation, water can be used for rinsing to achieve clean rinsing.

[0158] In some alternative embodiments, the first passivation includes using a chromium-free environmental passivation solution, which can be mixed from citric acid, cationic surfactant, corrosion inhibitor, and deionized water. In some alternative embodiments, the chromium-free environmental passivation solution includes the following components in percentage by weight: citric acid 20-35%, cationic surfactant 4.5-7%, corrosion inhibitor 0.5-1.5%, and the rest is deionized water. Illustratively, the pH of the chromium-free environmental passivation solution is 1.4-2.4, and the PT is 15-25. The passivation can be performed at a temperature of 60-65°C.

[0159] Illustratively, the PT value (Protection Time Value) generally refers to the durability or corrosion resistance of the protective film formed on the metal surface by the passivation solution. PT generally indicates the length of time for the metal sample after passivation treatment to begin to corrode or fail in a standard corrosion test environment (such as salt spray test).

[0160] In some alternative embodiments, the second passivation can use an environmental complexing agent to consolidate the passivation film formed.

[0161] In some alternative embodiments, the third passivation can use a chromium-free passivation agent. The chromium-free passivation agent includes a metal chelating agent and a surfactant, thereby enabling rapid penetration and passivation film formation in a short time. A layer of micro-nano composite oxide film with excellent hydrophobicity is formed on the metal surface, which does not contain elements such as phosphorus, sulfur, chromium, etc., has stable performance, can meet the biological safety requirements, and improves the corrosion resistance. Illustratively, the third shaft can be enlarged to the environmental complexing treatment agent (pH 4-6) at a temperature of 50-60°C for 10-15 min.

[0162] In some alternative embodiments, the third passivation can use a chromium-free passivation agent, and the pH of the chromium-free passivation agent is 7-8.5. The chromium-free passivation agent can be soaked at room temperature for 3-5 minutes.

[0163] In some alternative embodiments, the third heat treatment includes quenching at a temperature of 950-1030°C on the second shaft, followed by holding for 60-120 min; the target temperature for tempering is 400-600°C; and the holding time for tempering is 30-120 min.

[0164] Cr13 type martensitic stainless steel is a kind of stainless steel whose performance can be adjusted by heat treatment (quenching, tempering), and is a kind of hardenable stainless steel. The average content of Cr element is more than 12%, which determines its basic corrosion resistance. From 1Cr13 to 4Cr13, the carbon content gradually increases, and the strength increases accordingly. By using the above-mentioned third heat treatment process, the hardness, corrosion resistance and other characteristics can be improved, which is beneficial to meet the requirements of the bending stiffness of the material.

[0165] In some optional embodiments, the power output shaft 121 is made of Cr13 type martensitic stainless steel, and the hardness and stiffness of the power output shaft 121 are less than the hardness and stiffness of the distal bearing 13 and the hardness and stiffness of the proximal bearing 14.

[0166] In summary, through research and analysis, the power output shaft 121 prepared by the above-mentioned materials and processes has high bending stiffness or / and wear resistance, toughness, corrosion resistance, and meets the biological safety requirements, greatly improving the safety and reliability of the blood pumping motor 10.

[0167] Through research and analysis, the power output shaft 121 made of the original steel material with the brand SUS316L and SUS316LVM often has the problem of poor operation or premature failure of the blood pumping motor 10.

[0168] Taking the steel material with the brand SUS316L as an example, in the three-point bending test, the SUS316L steel material is made into an axis with a circular cross section, the diameter is 1mm, the support distance L is 8mm, and multiple SUS316L steel samples with the same specifications are selected for testing. The displacement and force curve of the SUS316L steel axis is shown in FIG. 5. Taking two samples as an example, the horizontal axis represents displacement, and the vertical axis represents force. The two curves in the figure are two SUS316L steel samples in cylindrical shape. As can be seen from the figure, when the displacement of the two samples is 0.4mm, the force is about 70-75N. The power output shaft made of these steel materials often has the problem of bending deformation, poor operation or premature failure of the blood pumping motor 10. The reason is that the bending stiffness and / or hardness of the SUS316L steel material may be low.

[0169] In subsequent research experiments, it is found that the power output shaft 121 made of non-magnetic tungsten steel material, high nitrogen steel material and martensitic stainless steel material solves the above-mentioned problems, and experiments are carried out respectively.

[0170] The displacement and force curve of the high-nitrogen steel material power output shaft 121 in the three-point bending test under the same conditions is shown in FIG. 6. The displacement and force curve of two high-nitrogen steel samples of the same size is shown in the figure. The steel sample is cylindrical, and the support distance L is 8 mm; it can be found from the figure that the force of the two samples is about 130-135 N when the displacement is 0.4 mm. That is, the high-nitrogen steel material power output shaft 121 needs a larger force to deform the power output shaft 121. Therefore, the power output shaft 121 runs well in the blood pump motor 10, and does not easily deform at high speed.

[0171] The displacement and force curve of the non-magnetic tungsten steel material power output shaft 121 in the three-point bending test under the same conditions is shown in FIG. 7. The displacement and force curve of three steel samples of the same size is shown in the figure. The steel sample is cylindrical, and the support distance L is 8 mm; it can be found from the figure that the force of the three samples is about 128-145 N when the displacement is 0.4 mm. That is, the non-magnetic tungsten steel material power output shaft 121 needs a larger force to deform the power output shaft 121, and therefore, the power output shaft 121 runs well in the blood pump motor 10, and does not deform at high speed.

[0172] The displacement and force curve of the Cr13 martensitic stainless steel material power output shaft 121 in the three-point bending test under the same conditions is shown in FIG. 8. The displacement and force curve of two Cr13 martensitic stainless steel samples of the same size is shown in the figure. The Cr13 martensitic stainless steel sample is cylindrical, and the support distance L is 8 mm; it can be found from the figure that the force of the two samples is about 95-100 N when the displacement is 0.4 mm. That is, the Cr13 martensitic stainless steel material power output shaft 121 needs a relatively large force to deform the power output shaft 121. Therefore, the power output shaft 121 runs well in the blood pump motor 10, and does not deform at high speed.

[0173] In addition, it is found through research that the non-magnetic tungsten steel has a suitable bending stiffness, and the hardness of the non-magnetic tungsten steel can be 65-75 HRC. The high-nitrogen steel or martensitic stainless steel has a suitable bending stiffness, and the hardness can be 45-55 HRC.

[0174] In summary, the above-mentioned elongated power output shaft 121 is arranged in the blood pumping motor 10. In the high-speed operating state, the power output shaft 121 is acted on by the proximal bearing, the distal bearing and the impeller, and can be in contact with blood on one side. In such a harsh working environment, the power output shaft 121 needs to have the above-mentioned hardness and bending stiffness to operate more stably, reduce failure and improve the reliability of the blood pumping motor 10.

[0175] In some optional embodiments, the wear resistance of the power output shaft 121 satisfies that, under the rated operating conditions of the blood pumping motor 10, the outer diameter of the power output shaft 121 is reduced by not more than 1% after 10 days of continuous rated operation. Optionally, the outer diameter of the power output shaft 121 can be reduced by 0.1%, 0.5%, 0.8% or the like after 10 days of continuous rated operation under the rated operating conditions of the blood pumping motor 10. Therefore, it is indicated that the above-mentioned power output shaft 121 has less reduction in outer diameter and does not deform after a long time of operation, especially in a blood medium, which is beneficial to improve the service life and operating stability of the blood pumping motor 10. In the present application, the material of the power output shaft 121 meets the biological safety requirements, i.e. meets GB / T 16886 Medical Devices Biological Evaluation Parts 3, 4, 6, 10, 11, GB / T 14233.1-2008 Medical Infusion, Blood Transfusion, Injection Appliance Test Method Part 1: Chemical Analysis Method and the like.

[0176] The specific structure of the blood pumping motor 10 in the present application will be further described below with reference to the accompanying drawings.

[0177] As shown in FIG. 3(a), in some embodiments of the present application, the blood pumping motor 10 further comprises a proximal bearing seat 17 connected to the proximal end of the stator assembly 11. The proximal bearing seat 17 is provided with a first mounting hole penetrating the proximal bearing 14 along the length direction x of the power output shaft 121. The proximal bearing 14 and the proximal cover 16 are both embedded in the first mounting hole, and the proximal cover 16 is located at the end of the proximal bearing 14 away from the distal bearing 13.

[0178] As shown in FIG. 3(a), in some embodiments of the present application, the blood pumping motor 10 further comprises a distal bearing seat 18 connected to the stator assembly 11. The distal bearing seat 18 is provided with a second mounting hole penetrating the distal bearing 13 along the length direction x of the power output shaft 121. The distal bearing 13 is sleeved on the power output shaft 121 and embedded in the second mounting hole. The distal bearing 13 is connected to the distal end of the stator assembly 11, penetrates the second mounting hole along the length direction x of the power output shaft 121, or is embedded in the second mounting hole.

[0179] It can be understood that the embedding of the proximal bearing 14 in the first mounting hole means that the outer circumferential surface of the proximal bearing 14 is embedded on the circumferential surface of the side of the proximal bearing 14 facing the first mounting hole and is fixedly connected. At the same time, the inner circumferential surface of the proximal bearing 14 is sleeved on the power output shaft 121 and is fixedly connected with the power output shaft 121. The same is true for the distal bearing 13. The distance between the distal bearing 13 and the proximal bearing 14 can be in the range of 8-20 mm.

[0180] In some embodiments of the present application, the iron core 111 can serve as a housing of the blood pumping motor 10. In other embodiments of the present application, the blood pumping motor comprises a housing which is sleeved outside the iron core 111.

[0181] Continuing to refer to FIG. 3(a), the blood pumping motor 10 further comprises a distal cover 15. The distal cover 15 is connected with the distal end of the stator assembly 11. The distal cover 15 is provided with a first through hole penetrating the distal cover 15 in the first direction. At least part of the power output shaft 121 extends out of the first through hole into the accommodation cavity 1111. The distal cover 15 is used to seal the distal end of the accommodation cavity 1111. At least the first through hole has a gap with the power output shaft 121. The power output shaft 121 contacts the first through hole, the distal bearing 13 and the proximal bearing 14. The force at multiple points acts on the power output shaft 121. The power output shaft 121 has good bending stiffness and appropriate deformation, which can effectively ensure the stable operation of the power output shaft 121, reduce the probability of deformation and bending of the power output shaft 121, leading to failure of the blood pumping motor 10, and improve the reliability of the blood pumping motor 10.

[0182] In addition, in the working state of the blood pumping motor 10, blood may exist in the gap between the first through hole and the power output shaft 121, affecting the operation of the power output shaft 121. The power output shaft 121 of the present application has good corrosion resistance and can withstand the corrosion of blood.

[0183] In some optional embodiments, the radial size of the first through hole is slightly larger than the radial size of the power output shaft 121, facilitating the rotation of the power output shaft 121. The distal cover 15 is provided with a first through hole penetrating the distal cover 15 in the first direction x. At least part of the power output shaft 121 extends out of the first through hole into the accommodation cavity 1111. The length of the power output shaft 121 extending out of the first through hole into the accommodation cavity 1111 can be in the range of 3-10 mm.

[0184] Continuing to refer to FIG. 3(a), the blood pumping motor 10 further comprises a proximal cover 16 connected with the proximal end of the stator assembly 11. The proximal cover 16 is provided with a second through hole penetrating the proximal cover 16 in the first direction x. The second through hole is used to directly or indirectly communicate with the accommodation cavity 1111. The proximal cover 16 is used to seal the proximal end of the accommodation cavity 1111. The first direction can be the length direction X.

[0185] In some embodiments of the present application, the blood pump motor 10 is provided with a flow cavity. The flow cavity is used for the flow and discharge of perfusion fluid, and the perfusion fluid contacts the power output shaft 121 when flowing. In some embodiments of the present application, the flow cavity is provided on the side of the blood pump motor 10 away from the impeller.

[0186] In some optional embodiments, the flow cavity includes a first flow cavity 1112 and a second flow cavity 1113, and the first flow cavity 1112 and the second flow cavity 1113 are communicated. When the blood pump device 1 is in a working state, the perfusion fluid can flow through the first flow cavity 1112, the containing cavity 1111 and the second flow cavity 1113, which can reduce the temperature of the blood pump motor 10. The power output shaft 121 is in contact with the perfusion fluid, and the perfusion fluid has a certain force and corrosion effect on the power output shaft 121, which affects the stability of the power output shaft 121. The power output shaft 121 of the present application has appropriate hardness, which improves the wear resistance and corrosion resistance of the power output shaft 121; the power output shaft 121 of the present application has appropriate bending stiffness, which reduces the moment deviation and impact effect of the perfusion fluid on the power output shaft 121, reduces the deformation of the power output shaft 121, and improves the running stability of the blood pump device 1.

[0187] In addition, the blood pump device 1 provided by the present embodiment can carry away the particles generated when the bearing rotates when the perfusion fluid flows through the distal bearing 13 and / or the proximal bearing 14, reduce the wear of the bearing, and further improve the service life of the blood pump motor 10.

[0188] In some optional embodiments, the interventional sheath assembly 30 includes a first conduit and a second conduit, the first conduit is communicated with the first flow cavity 1112, and the second conduit is communicated with the second flow cavity 1113. One of the first conduit and the second conduit is a perfusion conduit, and the other is a backflow conduit. The perfusion conduit is used for delivering perfusion fluid to the blood pump motor 10, and the backflow conduit is used for discharging the perfusion fluid in the blood pump motor 10. By communicating the first conduit and the second conduit with the blood pump motor 10, the perfusion fluid flows to the blood pump motor 10 through one of the conduits, and then flows through the first flow cavity 1112 and the containing cavity 1111 to carry away the heat generated by the blood pump motor 10. In some embodiments, the proximal bearing seat 17 is further provided with a first communication hole which directly or indirectly communicates the first flow cavity 1112 and the first conduit. Correspondingly, the related structure of the distal bearing seat 18 can be provided.

[0189] For example, the perfusion fluid flowing from the first flow cavity 1112 to the containing cavity 1111 flows out from the second conduit after sequentially passing through the distal bearing 13 and the proximal bearing 14, or the perfusion fluid flowing into the second conduit flows out from the first conduit after sequentially passing through the proximal bearing 14 and the distal bearing 13.

[0190] In some embodiments, the first conduit is a perfusion conduit, and the second conduit is a return conduit. The perfusion fluid of the first conduit flows through the first flow lumen 1112, the distal bearing 13, the accommodation lumen 1111, and the proximal bearing 14 in sequence, and then flows out of the blood pumping motor 10 through the second conduit.

[0191] In some embodiments, the connection between the first conduit and the proximal bearing 14 and the connection between the second conduit and the proximal cover 16 can be welded, glued, or sealed in other ways.

[0192] It can be understood that the components of the blood pumping device 1 that come into contact with the human body and blood need to be made of biologically safe materials, which can be metal or non-metal. For example, when these components are metal, they can be made of 316 stainless steel, which meets the relevant requirements for biological safety and compatibility. In other embodiments, the iron core 111 can also be used as the shell of the blood pumping motor 10 to directly contact the patient's tissue, so that the blood pumping motor 10 does not need to be additionally provided with a shell, thereby reducing the diameter of the blood pumping motor 10 and the difficulty of intervention.

[0193] It can be understood that the respective components or embodiments of the foregoing embodiments can be recombined. The above are only some examples, and any combination that meets the processing requirements and performance requirements is within the protection scope of the present application.

[0194] The present application also provides a pumping motor for a pumping device to pump a related fluid. The pumping motor includes a rotor assembly, the rotor assembly including a power output shaft, wherein the hardness of the power output shaft is greater than or equal to 45HRC, and the bending stiffness of the power output shaft is greater than or equal to 2100N·mm 2 In some application scenarios, the pumping device can pump body fluids such as interstitial fluid and digestive fluid.

[0195] It can be understood that the specific structure of the liquid pumping device refers to the blood pumping device 1 described above, and the working principle and the blood pumping device 1 are basically the same, and the same technical effects can be achieved as the blood pumping device 1, and will not be described in detail here.

[0196] In addition, the present application also provides a power output shaft, the hardness of the power output shaft is greater than or equal to 45HRC, and the bending stiffness of the power output shaft is greater than or equal to 2100N·mm 2 It can be understood that the power output shaft can be any one of the power output shafts of the blood pumping motor 10 or the pumping motor described above, and will not be described here.

[0197] The above is merely a specific implementation of the present application. As can be clearly understood by a person skilled in the art from the above description, for the convenience and brevity of description, the specific working process of the system, module and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be described herein again. It should be understood that the protection scope of the present application is not limited in this way, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed in the present application, and these modifications or replacements should be covered in the protection scope of the present application.

Claims

A blood pumping motor for pumping blood, the blood pumping motor comprising: A rotor assembly comprising a power output shaft, wherein the power output shaft has a hardness of greater than or equal to 45 HRC, the power output shaft has a bending stiffness of greater than or equal to 2100 N·mm 2 . The blood-pumping motor of claim 1, wherein The power output shaft satisfies one or more of the following conditions: 1) the bending stiffness of the power take-off shaft is 2260 N mm 2 up to 4800 N mm 2 ; 2) The hardness of the power output shaft is 55HRC to 65HRC; 3) The power output shaft is cylindrical, and the diameter of the power output shaft is 0.3mm to 1.5mm; 4) The cross-sectional shape of the power output shaft is N-sided polygon, N is a positive integer, N is greater than or equal to 6, and the outer diameter of the power output shaft is 0.3mm to 1.5mm; 5) The length of the power output shaft is 5mm to 30mm. The blood-pumping motor according to claim 2, wherein The power output shaft satisfies one or more of the following conditions: 1) The power output shaft is cylindrical, and the diameter of the power output shaft is 0.6mm to 1.0mm; 2) The cross-sectional shape of the power output shaft is N-sided polygon, N is a positive integer, N is greater than or equal to 6, and the outer diameter of the power output shaft is 0.6mm to 1.0mm; 3) The length of the power output shaft is 15mm to 25mm. The blood-pumping motor according to claim 2, wherein The blood pumping motor further comprises: a distal bearing, the distal bearing being sleeved on the power output shaft; a proximal bearing, the proximal bearing being sleeved on the power output shaft, and the proximal bearing being located on the proximal side of the distal bearing; an impeller, the impeller being rigidly connected with the power output shaft, and the impeller being arranged on the side of the distal bearing away from the proximal bearing. The blood-pumping motor according to claim 4, wherein The impeller is arranged at the distal end of the power output shaft, the length of the power output shaft between the impeller and the distal bearing is a, the total length of the power output shaft is b, and the length of the power output shaft satisfies a:b=1:(2 to 10). The blood-pumping electric motor according to claim 4 or 5, wherein In the working state of the blood pumping motor, the rotating speed of the power output shaft is 20000rpm to 50000rpm. The blood-pumping motor of claim 6, wherein The blood pumping motor is located in the body, and satisfies one or more of the following conditions: 1) The bending stiffness of the distal bearing is greater than or equal to the bending stiffness of the power output shaft; 2) The bending stiffness of the proximal bearing is greater than or equal to the bending stiffness of the power output shaft; 3) The hardness of the power output shaft is less than or equal to the hardness of the distal bearing and the proximal bearing, respectively. The blood-pumping motor of claim 1, wherein The rotor assembly further comprises a magnetic steel, the magnetic steel being sleeved on the power output shaft, and the blood pumping motor further comprises: a stator assembly, the stator assembly comprising a core, the core enclosing a containing cavity; at least part of the power output shaft and the magnetic steel being located in the containing cavity; a distal end cover, the distal end cover being connected with the distal end of the stator assembly, the distal end cover being provided with a first through hole penetrating through the distal end cover along the length direction of the power output shaft, at least part of the power output shaft extending out of the containing cavity from the first through hole, and at least the first through hole and the power output shaft having a gap. The blood-pumping motor of claim 8, wherein A flow-through cavity is arranged in the blood pumping motor, the flow-through cavity being used for the flow-through of perfusion liquid, and the perfusion liquid contacts the power output shaft when flowing through the flow-through cavity. The blood-pumping motor according to claim 4 or 5, wherein The material of the power output shaft comprises any one of high nitrogen steel, non-magnetic tungsten steel, and martensitic stainless steel. The blood-pumping motor of claim 10, wherein The preparation method of the power output shaft comprises: A high-nitrogen steel plate raw material is processed to obtain a predetermined power output shaft shape to obtain a first shaft, wherein the high-nitrogen steel plate raw material comprises the following chemical elements in mass percentage: C: 0.25% to 0.35%, Si ≤ 1.0%, Mn ≤ 1.0%, P ≤ 0.020%, Cr: 14% to 16%, Ni ≤ 0.5%, Mo: 0.85% to 1.1%, N: 0.3% to 0.5%, and the balance being Fe and other inevitable impurities; the first shaft is sequentially subjected to first heat treatment and finishing to obtain the power output shaft, wherein the first heat treatment sequentially comprises heating treatment, quenching treatment, cryogenic treatment and tempering treatment; the heating treatment comprises heating to 1010°C to 1060°C under a vacuum degree of ≤ 15 Pa; the cryogenic treatment comprises decreasing from room temperature to -80°C to -120°C within 15 min to 45 min, and then increasing to 20°C to 30°C at a rate of ≤ 5°C / min; and the target temperature of the tempering is 160°C to 220°C. The blood-pumping motor of claim 11, wherein The quenching treatment comprises any one of the following conditions: 1) oil quenching with a temperature of 25°C to 50°C; 2) oil quenching with a temperature of 25°C to 50°C, followed by flushing with a protective gas at 0.35 MPa to 0.8 MPa; 3) gas quenching by flushing with nitrogen at 0.35 MPa to 0.8 MPa. The blood-pumping motor of claim 10, wherein The preparation method of the power output shaft comprises: 75% to 94% tungsten carbide and 6% to 25% nickel are mixed and pressed to obtain a pressed blank; the pressed blank is sintered in a protective atmosphere at a pressure of 4 MPa to 10 MPa to obtain a first blank; the first blank is subjected to rough machining and finishing to obtain the power output shaft, wherein the method further comprises second heat treatment before or after the rough machining; and the second heat treatment comprises holding at a temperature of 450°C to 650°C for 60 min to 120 min. The blood-pumping motor of claim 10, wherein The preparation method of the power output shaft comprises: a Cr13 martensitic stainless steel is subjected to rough machining to obtain a predetermined power output shaft shape to obtain a second shaft; the second shaft is sequentially subjected to third heat treatment and finishing to obtain a third shaft; the third shaft is subjected to passivation treatment to obtain the power output shaft; wherein the passivation treatment comprises primary passivation, consolidation passivation and strengthening passivation; the passivation agent of the primary passivation is an environmentally friendly passivation liquid free of chromic acid, the environmentally friendly passivation liquid comprises citric acid, a cationic surfactant, an inhibitor and deionized water; the consolidation passivation uses an environmentally friendly complexing agent; and the strengthening passivation uses a chromium-free passivation agent, the chromium-free passivation agent comprises a metal chelating agent and a surfactant. The blood-pumping motor of claim 14, wherein The third heat treatment comprises quenching when the temperature of the second shaft is 950°C to 1030°C, followed by holding for 60 min to 120 min; the target temperature of the tempering is 400°C to 600°C; and the holding time of the tempering is 30 min to 120 min. The blood-pumping motor of claim 10, wherein The wear resistance of the power output shaft satisfies: under the rated working condition of the blood pumping motor, the outer diameter of the power output shaft is reduced by not more than 1% after continuous rated operation for 10 days. A blood pumping device comprising a distal blood flow passage assembly, an intervention sheath assembly and the blood pumping motor according to any one of claims 1 to 16 connected in sequence. A pumping motor for pumping a fluid, the pumping motor comprising: A rotor assembly comprising a power output shaft, wherein the power output shaft has a hardness of greater than or equal to 45 HRC; the power output shaft has a bending stiffness of greater than or equal to 2100 N·mm 2 . A power output shaft for the blood-pumping electric machine of any one of claims 1 to 17, the power output shaft having a hardness of greater than or equal to 45 HRC; the power output shaft having a bending stiffness of greater than or equal to 2100 N·mm 2 .

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