Magnetic liquid dual-suspension mixed-flow blood pump

Abstract

The application discloses a kind of magnetic liquid double-suspension mixed-flow blood pump, comprising: pump shell, impeller, for driving impeller rotation drive motor, front magnetic bearing and rear magnetic bearing, pump shell is provided with pump outer tube, coaxially nested in pump inner tube in pump outer tube and is communicated in the pump cavity of pump inner tube lower end;Impeller includes the screw rod type impeller of front section and the vertical sheet type impeller of rear section, screw rod type impeller is coaxially arranged in pump inner tube, and vertical sheet type impeller is arranged in pump cavity;Vertical sheet type impeller has multiple vertical blades in radial, and the upper and lower end surfaces of multiple vertical blades are all provided with inclined surface, and two inclined surfaces on each vertical blade and the upper and lower two sides of the inner wall of pump cavity are all formed with wedge-shaped hydrodynamic pressure structure with big upcurrent port and small backflow port.The application magnetic liquid double-suspension mixed-flow blood pump adopts double-suspension mechanism of magnetic suspension and hydraulic suspension, can improve the stability and reliability of blood pump, and also greatly improves the work efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a magnetic fluid double-suspension mixed-flow blood pump. Background Art

[0002] Artificial heart assist devices, referred to as "blood pumps," are considered the most important and promising treatment for many patients with advanced heart failure.

[0003] Currently, impeller-type blood pumps have become the mainstream product in clinical applications. The blood pumps currently available on the market can be roughly divided into two types: centrifugal blood pumps and axial-flow blood pumps. Both types of blood pumps have their own technical advantages and disadvantages: the advantage of axial-flow blood pumps is high flow rate, but the disadvantages are low pressure head and relatively low mechanical efficiency; the advantage of centrifugal blood pumps is high pressure head, but the disadvantage is relatively low flow rate. There are three main types of impeller support for existing blood pumps: the first is a mechanical bearing blood pump, the second is a hydraulic suspension blood pump, and the third is a magnetic suspension blood pump. Due to their short mechanical lifespan and relatively high incidence of complications, mechanical bearing blood pumps have been gradually replaced by the other two types. However, while the second and third suspension bearing structures can overcome the short mechanical lifespan of blood pumps, their impact stability and reliability are significantly insufficient. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a magnetic fluid double-suspension mixed-flow blood pump, which improves the stability and reliability of the blood pump and can take into account the advantages of axial flow blood pumps and centrifugal blood pumps. Under the same work conditions, the pressure head and flow rate generated are greater, and the work efficiency is greatly improved.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a magnetic fluid double suspension mixed flow blood pump, comprising:

[0006] A pump housing is provided with a pump outer tube, a pump inner tube coaxially nested in the pump outer tube, and a pump cavity connected to the lower end of the pump inner tube;

[0007] The impeller includes a screw impeller at the front section and a vertical vane impeller at the rear section, wherein the screw impeller is coaxially arranged in the pump inner tube, and the vertical vane impeller is arranged in the pump chamber; the vertical vane impeller has a plurality of radial vertical blades, and the upper and lower end surfaces of the plurality of vertical blades are provided with inclined surfaces, and a wedge-shaped hydrodynamic structure with a large upstream port and a small downstream port is formed between the two inclined surfaces on each vertical blade and the upper and lower inner walls of the pump chamber;

[0008] A drive motor, built into the pump housing and the impeller, for driving the impeller to rotate;

[0009] The front magnetic bearing comprises an inner magnetic core group built in the impeller near the top position and an outer magnetic ring group built between the outer tube of the pump and the inner tube of the pump, and the outer magnetic ring group repels the inner magnetic core group radially.

[0010] The rear magnetic bearing comprises an upper magnetic ring built in the bottom of the impeller and a lower magnetic ring built in the pump cavity, and the lower magnetic ring is coaxially arranged below the upper magnetic ring and attracts the upper magnetic ring.

[0011] As a further improvement of the present application, the screw impeller has a hub and a plurality of helical blades arranged along the outer circumferential surface of the hub, which can drive blood to flow along the axis of the inner tube of the pump when following the rotating movement of the impeller.

[0012] As a further improvement of the present application, the number of the helical blades is 2-5; and the number of the vertical blades is 3-6.

[0013] As a further improvement of the present application, the inner magnetic core group and the outer magnetic ring group are both forcibly spliced by at least two magnetic sheets in the same-pole opposite manner.

[0014] Among them, the S pole and the N pole of the magnetic sheet are respectively on the upper and lower sides.

[0015] As a further improvement of the present application, the outer ring of the upper magnetic ring is N pole and the inner ring is S pole, and the outer ring of the lower magnetic ring is S pole and the inner ring is N pole.

[0016] Or the outer ring of the upper magnetic ring is S pole and the inner ring is N pole, and the outer ring of the lower magnetic ring is N pole and the inner ring is S pole.

[0017] As a further improvement of the present application, the upper magnetic ring and the lower magnetic ring are both integral; or the upper magnetic ring and the lower magnetic ring are both forcibly spliced by at least two fan-shaped magnetic tiles.

[0018] Among them, the S pole and the N pole of the magnetic tile are respectively on the inner and outer sides.

[0019] As a further improvement of the present application, the driving motor comprises a motor winding and a motor rotor, the motor winding is built in between the outer tube of the pump and the inner tube of the pump, and the motor rotor is built in the impeller and opposite to the motor winding.

[0020] As a further improvement of the present application, it further comprises a plurality of magnetic shields installed in the pump shell and the impeller and distributed on the outer sides of the upper and lower ends of the motor winding and the motor rotor.

[0021] The magnetic shields are all made of ferrous soft magnetic materials.

[0022] As a further improvement of the present invention, the inner bottom wall of the pump chamber extends inwardly opposite to the impeller to form a pump chamber boss, and the lower magnetic ring is built into the pump chamber boss; the top of the pump chamber boss is inlaid with a ceramic ball, and the bottom of the impeller is installed with a ceramic sheet, and the ceramic sheet is supported on the ceramic ball.

[0023] As a further improvement of the present invention, the inclination angle of the inclined surface is 1 to 15°.

[0024] The beneficial effects of the present invention are:

[0025] 1. The present invention provides a magnetic fluid double-suspension mixed-flow blood pump, the impeller of which is provided with a screw impeller at the front section and a vertical vane impeller at the rear section. The screw impeller cooperates with the pump inner tube to form an axial flow pump, and the vertical vane impeller cooperates with the pump chamber to form a centrifugal pump. The axial flow pump at the front section and the centrifugal pump at the rear section both perform work. The combination of the two forms a mixed-flow pump, which takes into account the advantages of both axial flow pumps and centrifugal pumps, generates a large pressure head and flow rate, and greatly improves the working efficiency.

[0026] 2. Under the joint action of the front magnetic bearing and the rear magnetic bearing, the impeller maintains a radial suspension state with good suspension effect, which improves the impact resistance, stability and reliability.

[0027] 3. The upper and lower end surfaces of the vertical blades of the impeller are both inclined, forming a wedge-shaped hydrodynamic structure with the inner surface of the pump chamber. When the impeller rotates, the upstream port of the wedge-shaped groove is large and the downstream port is small, which can generate hydraulic and automatically adjusted liquid suspension. The impeller will maintain axial suspension. The radial suspension of the impeller is combined with the axial suspension to achieve all-round position-controlled suspension, thereby ensuring stable operation.

[0028] 4. This application adopts a dual suspension mechanism of magnetic suspension plus hydraulic suspension, which can improve the stability and reliability of the blood pump and reduce hemolysis and thrombosis complications; at the same time, the volume and weight of the blood pump are small, which can reduce the surgical invasiveness of the blood pump and improve the practicality of the blood pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a cross-sectional view of the magnetic fluid double-suspension mixed-flow blood pump of the present invention;

[0030] Figure 2 This is a front view of the impeller in the magnetic fluid double-suspension mixed-flow blood pump of the present invention;

[0031] Figure 3 A perspective view of a vertical blade impeller in a magnetic fluid dual-suspension mixed-flow blood pump according to the present invention;

[0032] Figure 4 This is a schematic structural diagram of the rear magnetic bearing in the magnetic fluid dual-suspension mixed-flow blood pump of the present invention;

[0033] Figure 5Figure 1 is a top view of the upper magnetic ring assembled by three magnetic tiles in the magnetic liquid dual-suspension mixed-flow blood pump of the present application;

[0034] wherein, Figure 3 The arrow direction is the rotating direction of the impeller when the blood pump is working.

[0035] The following description is made in conjunction with the accompanying drawings:

[0036] 1, pump housing; 101, pump outer tube; 102, pump inner tube; 103, pump cavity; 2, impeller; 201, vertical blade; 2011, inclined surface; 202, hub; 203, spiral blade; 3, drive motor; 301, motor winding; 302, motor rotor; 4, front magnetic bearing; 401, inner magnetic core group; 402, outer magnetic ring group; 5, rear magnetic bearing; 501, upper magnetic ring; 502, lower magnetic ring; 6, ceramic ball; 7, ceramic sheet; 8, magnetic shielding. DETAILED DESCRIPTION

[0037] The following describes a preferred embodiment of the present application in conjunction with the accompanying drawings.

[0038] Referring to Figures 1 to 5 The present application provides a magnetic liquid dual-suspension mixed-flow blood pump, comprising: a pump housing 1, an impeller 2, a drive motor 3, a front magnetic bearing 4, a rear magnetic bearing 5, a positioning ceramic bearing, and a plurality of magnetic shielding 8.

[0039] The pump housing 1 is provided with a pump outer tube 101, a pump inner tube 102, and a pump cavity 103. The pump outer tube 101 and the pump inner tube 102 are arranged vertically, and the pump inner tube 102 is coaxially nested in the pump outer tube 101, and there is a containing space between them for installing the components of the drive motor 3 and the front magnetic bearing 4. The pump cavity 103 is arranged below the pump inner tube 102 and is in communication with the lower end of the pump inner tube 102. The pump housing 1 is provided with a pump outlet on one side of the pump cavity 103, which is in communication with the pump cavity 103 and serves as a blood outlet. The upper end of the pump inner tube 102 is a blood inlet, and the top of the pump outer tube 101 is provided with an inlet support that extends above the pump inner tube 102 to prevent the blood pump from being sucked by the interventricular septum due to negative pressure when the blood pump is working, resulting in pump failure and embolism.

[0040] Referring to Figures 1 to 3The impeller 2 includes a front-end screw impeller and a rear-end vertical blade impeller. The screw impeller is coaxially arranged in the pump inner tube 102. The screw impeller has a hub 202 and a plurality of spiral blades 203 arranged along the outer circumference of the hub 202. Optionally, the number of spiral blades 203 is 2 to 5. When the spiral blades 203 rotate with the impeller 2, they can drive the blood to flow along the axis of the pump inner tube 102 into the pump chamber 103. The vertical blade impeller is seamlessly welded to the lower end of the screw impeller and arranged in the pump chamber 103. The vertical blade impeller has a plurality of radially curved vertical blades 201. Optionally, the number of vertical blades 201 is 3 to 6. When the vertical blades 201 rotate with the impeller 2, they can drive the blood in the pump chamber 103 to flow along the radial direction of the impeller 2, so that the blood flows out from the pump outlet.

[0041] Furthermore, the drive motor 3 is built into the pump housing 1 and the impeller 2 to drive the impeller 2 to rotate. Specifically, the drive motor 3 includes a motor winding 301 and a motor rotor 302. The motor winding 301 is built into the accommodation space between the pump outer tube 101 and the pump inner tube 102. The motor rotor 302 is a two-pole or four-pole magnetic core built into the middle of the screw impeller of the impeller 2 and is connected to the impeller 2 as a whole. The motor rotor 302 and the motor winding 301 are arranged opposite each other, thereby integrating the drive motor 3 with the liquid pump, thereby forming a "pump-motor" integration.

[0042] In this application, a screw impeller is combined with the pump inner tube 102 to form an axial flow pump, and a vertical vane impeller is combined with the pump chamber 103 to form a centrifugal pump. Driven by the drive motor 3, the impeller 2 rotates, and the axial flow pump in the front section and the centrifugal pump in the rear section both perform work. The two are combined into a mixed flow pump, which greatly improves efficiency.

[0043] See Figure 1 The front magnetic bearing 4 includes an inner magnetic core group 401 and an outer magnetic ring group 402. The inner magnetic core group 401 is built into the impeller 2 near the top, and the outer magnetic ring group 402 is built into the accommodation space between the pump outer tube 101 and the pump inner tube 102. The outer magnetic ring group 402 and the inner magnetic core group 401 are arranged opposite each other. The inner magnetic core group 401 and the outer magnetic ring group 402 are both forcibly spliced ​​together with at least two magnetic sheets with the same poles facing each other, with the south pole and north pole of the magnetic sheets located at the top and bottom, respectively.

[0044] In detail, in a preferred embodiment, the inner magnetic core group 401 is composed of, but not limited to, three circular magnetic sheets stacked together, the upper layer of the first circular magnetic sheet is S-pole and the lower layer is N-pole, the upper layer of the second circular magnetic sheet is N-pole and the lower layer is S-pole, and the upper layer of the third circular magnetic sheet is S-pole and the lower layer is N-pole, so as to forcibly splice the three circular magnetic sheets into a whole with the same poles opposite to each other. The outer magnetic ring group 402 is composed of, but not limited to, three circular magnetic rings stacked together, corresponding to the inner magnetic core group 401, the first circular magnetic ring is arranged with the upper layer as S-pole and the lower layer as N-pole, the upper layer of the second circular magnetic ring is N-pole and the lower layer is S-pole, and the upper layer of the third circular magnetic ring is S-pole and the lower layer is N-pole, so as to forcibly splice the three circular magnetic rings into a whole with the same poles opposite to each other. Among them, the three circular magnetic sheets and the three circular magnetic rings correspond to each other in the horizontal direction, or are slightly offset up and down, so that the outer magnetic ring group 402 and the inner magnetic core group 401 repel in the radial direction, thereby positioning the upper end of the impeller 2 radially in the center and keeping the upper end of the impeller 2 in a radially suspended state.

[0045] Continuing to refer to Figure 1 , the rear magnetic bearing 5 includes an upper magnetic ring 501 built in the bottom of the screw impeller and a lower magnetic ring 502 built in the pump cavity 103. The inner bottom wall of the pump cavity 103 extends inwardly opposite to the impeller 2 to form a pump cavity boss, the lower magnetic ring 502 is fixed in the pump cavity boss, and the lower magnetic ring 502 is coaxially arranged directly below the upper magnetic ring 501, and the lower magnetic ring 502 and the upper magnetic ring 501 attract each other in the axial direction.

[0046] Referring to Figure 4 , the inner and outer diameters of the upper magnetic ring 501 and the lower magnetic ring 502 are matched, the outer ring of the upper magnetic ring 501 is N-pole and the inner ring is S-pole, the outer ring of the lower magnetic ring 502 is S-pole and the inner ring is N-pole; or the outer ring of the upper magnetic ring 501 is S-pole and the inner ring is N-pole, and the outer ring of the lower magnetic ring 502 is N-pole and the inner ring is S-pole. Through the use of this structure design, the upper magnetic ring 501 and the lower magnetic ring 502 are both arranged with one magnetic pole in the outer ring and one magnetic pole in the inner ring, and the inner and outer ring magnetic poles of the upper magnetic ring 501 and the lower magnetic ring 502 are opposite, so that the outer ring of the upper magnetic ring 501 and the outer ring of the lower magnetic ring 502 attract each other, and the inner ring of the upper magnetic ring 501 and the inner ring of the lower magnetic ring 502 also attract each other, relying on the attraction force to keep them concentric, thereby positioning the lower end of the impeller 2 radially in the center; even if the impeller 2 is offset or eccentric up and down, the repulsive force also works at the same time, so that the upper magnetic ring 501 returns to the central position, that is, the impeller 2 is centered. The impeller 2 is kept in a radially suspended state under the joint action of the front magnetic bearing 4 and the rear magnetic bearing 5, and the suspension effect is good, the impact resistance, stability and reliability are greatly improved.

[0047] Among them, the magnetic materials used in the inner magnetic core group 401, the outer magnetic ring group 402, the upper magnetic ring 501 and the lower magnetic ring 502 are all strong magnetic neodymium iron boron.

[0048] It can be understood that the upper magnetic ring 501 and the lower magnetic ring 502 can be integrated or can be forcibly spliced by at least two magnetic tiles.

[0049] As shown in Figure 5 , in one embodiment, the upper magnetic ring 501 is composed of three identical magnetic tiles, the outer arc of the magnetic tile is S pole, the inner arc is N pole, the N poles of the three magnetic tiles are opposite, the S poles are opposite, and the three magnetic tiles are forcibly spliced into an annular upper magnetic ring 501. Of course, the upper magnetic ring 501 can also be spliced by two, four or more pieces, which can achieve the same effect, and will not be illustrated one by one here.

[0050] The positioning ceramic bearing includes a ceramic ball 6 and a ceramic sheet 7, the ceramic ball 6 is embedded on the top of the pump cavity boss and at least partially exposed on the outside. The ceramic sheet 7 is fixedly installed on the bottom of the screw impeller and abuts against the bottom surface of the upper magnetic ring 501, and the ceramic sheet 7 is carried on the ceramic ball 6. When the blood pump is started to a certain speed, the impeller 2 is axially suspended, and the ceramic sheet 7 and the ceramic ball 6 are separated.

[0051] A plurality of magnetic shielding members 8 are installed on the pump shell 1 and inside the impeller 2 and distributed on the upper and lower ends of the motor winding 301 and the motor rotor 302. Specifically, the plurality of magnetic shielding members 8 include an upper magnetic shielding ring, a lower magnetic shielding ring, an upper magnetic shielding ring, and a lower magnetic shielding ring. The upper magnetic shielding ring is arranged between the motor winding 301 and the outer magnetic ring group 402, the lower magnetic shielding ring is arranged between the motor winding 301 and the upper cover of the pump cavity 103, the upper magnetic shielding ring is arranged between the motor rotor 302 and the inner magnetic core group 401, and the lower magnetic shielding ring is arranged between the motor rotor 302 and the upper magnetic ring 501. Among them, the magnetic shielding member 8 is made of ferrous soft magnetic material.

[0052] Referring to Figure 3 , the upper and lower end surfaces of the plurality of vertical vanes 201 are provided with inclined surfaces 2011, and the upper and lower inclined surfaces 2011 of each vertical vane 201 form a wedge-shaped groove with the upper cavity inner wall and the lower cavity inner wall of the pump cavity 103, respectively, and the wedge-shaped groove has a large inflow port and a small backflow port along the rotation direction. After the impeller 2 rotates, the incompressible liquid flow enters the wedge-shaped groove from the inflow port, and the liquid dynamic pressure is generated due to the extrusion, and the size of the liquid dynamic pressure is positively correlated with the rotation speed of the impeller 2, positively correlated with the wedge-shaped groove angle, and negatively correlated with the wedge-shaped space.

[0053] It should be noted that the wedge-shaped spaces within the wedge-shaped grooves on the upper and lower sides of vertical blades 201 change as impeller 2 moves up and down. The closer the inclined surface 2011 of vertical blade 201 is to the inner wall of pump chamber 103, the greater the generated hydrodynamic pressure, and vice versa. The thrust generated by the hydrodynamic pressure at the upper and lower ends of vertical blade 201 is a set of opposing axial forces. Because these forces automatically adjust as the upper and lower wedge-shaped spaces of impeller 2 change, axially levitating impeller 2, this axial levitation is considered self-suspension. In other words, within a certain speed range, the axial forces acting on impeller 2 can automatically balance, resulting in automatic axial levitation.

[0054] Optionally, the inclination angle of the inclined surface 2011 is 1 to 15°.

[0055] As described above, the radial suspension of the impeller 2 is combined with the axial suspension to achieve all-round position-controlled suspension, thereby ensuring smooth operation.

[0056] To facilitate understanding, the axial force on the impeller 2 during operation of the blood pump is analyzed. This mainly includes:

[0057] The first axial force is the impact of the blood pump inlet flow on the impeller 2, which is in the axially downward direction and has a positive correlation with the rotational speed;

[0058] The second axial force is the thrust generated by the pressure difference between the blood outflow outlet and the blood inlet of the blood pump. The direction is axially upward and the magnitude is positively correlated with the rotational speed.

[0059] The third axial force is the axial component of the weight of the motor rotor 302 and the impeller 2, which is directed downward and changes only with the adjustment of the blood pump posture;

[0060] The fourth axial force is the axial thrust generated by the front magnetic bearing 4 on the impeller 2, which is in an upward or downward direction. The magnitude and direction of the force will change with the upward and downward offset positions of the inner magnetic core group 401 and the outer magnetic ring group 402.

[0061] The fifth axial force is the axial support force of the ceramic balls 6, which is in an upward direction and disappears after the impeller 2 is suspended;

[0062] The sixth axial force is the axial suction force generated by the rear magnetic bearing 5 on the impeller 2, which is directed downward;

[0063] The seventh axial force is the axial thrust of the hydrodynamic pressure generated in the wedge-shaped groove on the upper side of the vertical blade 201, which is in the axially downward direction;

[0064] The eighth axial force is the axial thrust of the hydrodynamic pressure generated in the wedge-shaped groove on the lower side of the vertical blade 201, and its direction is axially upward.

[0065] The seventh axial force and the eighth axial force are positively correlated with the rotation speed, positively correlated with the wedge angle, and negatively correlated with the size of the wedge space in an exponential relationship. The first axial force to the sixth axial force are passive forces, which are weak forces. The seventh axial force and the eighth axial force are active forces, which are strong forces. The seventh axial force and the eighth axial force are automatically balanced after overcoming the first axial force to the sixth axial force, and the motor rotor 302 and the impeller 2 are axially suspended when the sum of the axial force vectors is zero.

[0066] Therefore, compared with the existing mechanical bearing blood pump, the motor rotor 302 and the impeller 2 of the blood pump are in a full-range controlled and suspended state during normal operation, the bearing has no friction, hemolysis can be reduced, the service life of the blood pump can be prolonged, and thrombosis complications triggered by friction heating can be reduced.

[0067] Compared with the existing centrifugal blood pump and axial flow blood pump, the application can take into account the advantages of the axial flow blood pump and the centrifugal blood pump, overcome the disadvantages of the two, and have larger pressure head and flow under the same work condition, and the work efficiency is greatly improved.

[0068] Compared with the existing liquid suspension blood pump and magnetic suspension blood pump, the application adopts a double-suspension mechanism of magnetic suspension and hydraulic suspension, which can improve the stability and reliability of the blood pump.

[0069] In addition, the blood pump of the application has small volume and weight, can reduce the surgical invasiveness of the blood pump, improve the practicability, and the internal structure of the full-suspension blood pump is simple and smooth, without dead space or dead angle, which can also effectively prevent thrombus formation.

[0070] In the above description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the above description is only a preferred embodiment of the present application, and the present application can be implemented in many other ways different from those described herein, so the present application is not limited to the specific implementations disclosed above. Meanwhile, any person skilled in the art can make many possible changes and modifications to the technical solutions disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of the present application. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the scope of the technical solutions of the present application, all still belong to the scope of protection of the technical solutions of the present application.

Claims

1. A magnetic fluid double suspension mixed flow blood pump, characterized in that: include: A pump housing (1) is provided with a pump outer tube (101), a pump inner tube (102) coaxially nested in the pump outer tube (101), and a pump cavity (103) connected to the lower end of the pump inner tube (102); An impeller (2) comprising a front-end screw impeller and a rear-end vertical blade impeller, wherein the screw impeller is coaxially arranged in the pump inner tube (102), and the vertical blade impeller is arranged in the pump cavity (103); the vertical blade impeller has a plurality of radial vertical blades (201), and the upper and lower end surfaces of the plurality of vertical blades (201) are provided with inclined surfaces (2011), and a wedge-shaped hydrodynamic structure with a large upstream port and a small downstream port is formed between the two inclined surfaces (2011) on each vertical blade (201) and the upper and lower inner walls of the pump cavity (103); A drive motor (3), built into the pump housing (1) and the impeller (2), for driving the impeller (2) to perform rotational motion; The front magnetic bearing (4) comprises an inner magnetic core group (401) built into the impeller (2) near the top and an outer magnetic ring group (402) built into the pump outer tube (101) and the pump inner tube (102), wherein the outer magnetic ring group (402) and the inner magnetic core group (401) repel each other radially; the inner magnetic core group (401) and the outer magnetic ring group (402) are both formed by forcibly splicing at least two magnetic sheets in a manner of facing each other with the same poles, and the S pole and N pole of the magnetic sheet are respectively located at the upper and lower sides; A rear magnetic bearing (5) comprises an upper magnetic ring (501) built into the bottom of the impeller (2) and a lower magnetic ring (502) built into the pump chamber (103), wherein the lower magnetic ring (502) is coaxially arranged below the upper magnetic ring (501) and attracts each other; the outer ring of the upper magnetic ring (501) is an N pole and the inner ring is an S pole, and the outer ring of the lower magnetic ring (502) is an S pole and the inner ring is an N pole; or the outer ring of the upper magnetic ring (501) is an S pole and the inner ring is an N pole, and the outer ring of the lower magnetic ring (502) is an N pole and the inner ring is an S pole.

2. The magnetic fluid dual-suspension mixed-flow blood pump according to claim 1, characterized in that: The screw impeller comprises a hub (202) and a plurality of spiral blades (203) arranged along the outer peripheral surface of the hub (202). The spiral blades (203) can drive blood to flow along the axial direction of the pump inner tube (102) when rotating in accordance with the impeller (2).

3. The magnetic fluid dual-suspension mixed-flow blood pump according to claim 2, characterized in that: The number of the spiral blades (203) is 2 to 5; the number of the vertical blades (201) is 3 to 6.

4. The magnetic fluid dual-suspension mixed-flow blood pump according to claim 1, characterized in that: The upper magnetic ring (501) and the lower magnetic ring (502) are both integral; or the upper magnetic ring (501) and the lower magnetic ring (502) are both formed by forcibly splicing at least two fan-shaped magnetic tiles; The S pole and N pole of the magnetic tile are located at the inner and outer sides respectively.

5. The magnetic fluid dual-suspension mixed-flow blood pump according to claim 1, characterized in that: The drive motor (3) comprises a motor winding (301) and a motor rotor (302); the motor winding (301) is built between the pump outer tube (101) and the pump inner tube (102); and the motor rotor (302) is built into the impeller (2) and is opposite to the motor winding (301).

6. The magnetic fluid dual-suspension mixed-flow blood pump according to claim 5, characterized in that: It also includes a plurality of magnetic shielding members (8) installed in the pump housing (1) and the impeller (2) and distributed outside the upper and lower ends of the motor winding (301) and the motor rotor (302); The magnetic shielding parts (8) are all made of ferrous soft magnetic material.

7. The magnetic fluid dual-suspension mixed-flow blood pump according to claim 1, characterized in that: The inner bottom wall of the pump chamber (103) extends inwardly opposite to the impeller (2) to form a pump chamber boss, and the lower magnetic ring (502) is built into the pump chamber boss; a ceramic ball (6) is embedded on the top of the pump chamber boss, and a ceramic sheet (7) is installed on the bottom of the impeller (2), and the ceramic sheet (7) is supported on the ceramic ball (6).

8. The magnetic fluid dual-suspension mixed-flow blood pump according to claim 1, characterized in that: The inclination angle of the inclined surface (2011) is 1 to 15 degrees.

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