Hybrid magnetic suspension centrifugal blood pump

Abstract

Disclosed in the present invention is a hybrid magnetic suspension centrifugal blood pump, comprising a pump housing, a rotor impeller, a drive motor, a rotor permanent magnetic suspension bearing, an impeller permanent magnetic suspension bearing, and an electromagnetic suspension bearing. The pump housing is provided with a pump head and a pump cavity; the rotor impeller comprises a rotor and an impeller integrally connected to the rotor; the rotor permanent magnetic suspension bearing is arranged at the upper end of the rotor and in the pump head, and the rotor can be radially centered under the acting force of the rotor permanent magnetic suspension bearing; the impeller permanent magnetic suspension bearing is arranged on an impeller lower cover and the lower wall of the pump cavity, and the impeller can be radially centered under the acting force of the impeller permanent magnetic suspension bearing; the electromagnetic suspension bearing comprises an electric control magnetic core fixed to the rotor, an electric control magnetic ring fixed to an impeller upper cover, and a plurality of electromagnets, wherein each electromagnet comprises an L-shaped iron core and a coil wound around the iron core, and the two ends of the iron core are arranged opposite to the electric control magnetic core and the electric control magnetic ring, respectively. According to the present invention, the five-degrees-of-freedom stable suspension operation of the blood pump can be achieved, and the size and weight of the blood pump can be reduced.

Description

Hybrid magnetic levitation centrifugal blood pump Technical Field

[0001] The present invention relates to the technical field of ventricular assist devices, and in particular to a hybrid magnetic levitation centrifugal blood pump. Background Art

[0002] In recent years, the use of implantable heart-assist blood pumps has become an effective clinical treatment for advanced heart failure, with results comparable to heart transplantation. The development of suspended blood pumps without mechanical bearings has become a mainstream approach in the development of artificial heart-assist blood pumps. For example, the HeartMate3 and HeartWare centrifugal blood pumps, commonly used in the United States, have been used in tens of thousands of clinical cases. However, fully magnetically levitated blood pumps, such as the HeartMate3, are difficult to implant in patients due to the complex five-degree-of-freedom magnetic levitation control and their large size, making them unsuitable for smaller individuals, such as Asians. Magnetic fluid-suspended blood pumps, such as the HeartWare, are primarily supported by hydrodynamic bearings, resulting in severe blood damage after surgery and a high rate of complications such as hemolysis and stroke, making them unsuitable for long-term use and, as a result, have been suspended by the US FDA.

[0003] Magnetic levitation technology for blood pumps needs to address the issues of suspension and stability in five degrees of freedom, and also requires the blood pump to be small and lightweight. Magnetic levitation bearings are generally divided into two types: permanent magnetic bearings and electromagnetic bearings. Permanent magnetic bearings are passive magnetic bearings with advantages such as a simpler structure, no need for electronic control, and a smaller size. However, their disadvantages are poor rigidity, particularly when the supported body undergoes axial displacement, which leads to displacement oscillation and poor system reliability. Existing blood pumps rely solely on permanent magnetic bearings to achieve five-degree-of-freedom suspension of the rotor impeller, and their stability is poor, especially with regard to the deflection degrees of freedom. Electromagnetic bearings are actively controlled magnetic bearings with advantages such as controllable rigidity and good stability. However, using only electromagnetic bearings to achieve five-degree-of-freedom suspension of the rotor impeller presents a high level of technical difficulty, resulting in a complex blood pump system and structure, large size, and heavy weight. Therefore, it is necessary to improve the existing technology to overcome its shortcomings.

[0004] Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a hybrid magnetic levitation centrifugal blood pump. By setting a rotor permanent magnetic levitation bearing, an impeller permanent magnetic levitation bearing and an electromagnetic levitation bearing, the five-degree-of-freedom stable suspension operation of the blood pump can be effectively achieved. This hybrid magnetic levitation bearing can also solve the problems of large volume and weight of the blood pump.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a hybrid magnetic levitation centrifugal blood pump, comprising:

[0007] The pump housing is provided with a pump head and a pump cavity, wherein the pump head is vertically connected to the top of the pump cavity, and a central cone protruding into the cavity is provided in the middle of the lower wall of the pump cavity;

[0008] The rotor impeller comprises a rotor passing through the pump head and an impeller built into the pump chamber, the rotor and the impeller being fixedly connected as a whole and supported on the central cone; the impeller is provided with a plurality of blades distributed around its central axis, an impeller upper cover fixedly connected to the tops of the plurality of blades, and an impeller lower cover fixedly connected to the bottoms of the plurality of blades, the impeller upper cover and the upper wall of the pump chamber are gap-matched to form an upper secondary flow channel, the upper secondary flow channel is connected to the interior of the impeller through an inlet provided on the impeller upper cover; the impeller lower cover and the lower wall of the pump chamber are gap-matched to form a lower secondary flow channel, the lower secondary flow channel is connected to the interior of the impeller through a reverse flow port provided on the impeller lower cover, and the area of ​​the reverse flow port is smaller than the area of ​​the inlet port;

[0009] A driving motor for driving the rotor to drive the impeller to rotate;

[0010] A rotor permanent magnetic suspension bearing is arranged at the upper end of the rotor and in the pump head, and the rotor can be radially centered under the action of the rotor permanent magnetic suspension bearing;

[0011] An impeller permanent magnetic suspension bearing is arranged on the impeller lower cover and the lower wall of the pump chamber, and the impeller can be radially centered under the force of the impeller permanent magnetic suspension bearing;

[0012] An electromagnetic levitation bearing includes an electrically controlled magnetic core fixed to the rotor, an electrically controlled magnetic ring fixed to the impeller cover, and a plurality of electromagnets. The plurality of electromagnets are arranged at the top of the pump chamber and are distributed in a ring-shaped manner with equal intervals around the rotor. The electromagnets include an L-shaped iron core and a coil wound around the iron core. The two ends of the iron core are respectively arranged opposite to the electrically controlled magnetic core and the electrically controlled magnetic ring.

[0013] As a further improvement of the present invention, a cover hole is provided in the middle of the impeller cover, the lower end of the rotor passes through the cover hole and extends to the middle of the impeller and is fixedly connected to the blades, and the inlet is formed by the gap between the impeller cover and the rotor;

[0014] A lower cover hole is opened in the middle of the impeller lower cover, the upper end of the center cone passes through the lower cover hole and extends to the middle of the impeller, and the backflow port is formed by the gap between the impeller lower cover and the center cone.

[0015] As a further improvement of the present invention, the plurality of blades are equally divided into a plurality of long blades and a plurality of short blades, the plurality of long blades and the plurality of short blades are staggered and distributed at intervals in the circumferential direction, and the long blades are fixedly connected to the lower end of the rotor, and the ends of the short blades pointing to the center axis do not contact the rotor.

[0016] As a further improvement of the present invention, the rotor permanent magnetic suspension bearing includes an outer magnetic ring group and an inner magnetic ring group, the outer magnetic ring group is built into the pump head, and the inner magnetic ring group is built into the upper end of the rotor and coaxially distributed in the middle of the outer magnetic ring group; the outer magnetic ring group includes a main outer magnetic ring, and the inner magnetic ring group includes a main inner magnetic ring, and the main outer magnetic ring and the main inner magnetic ring are both magnetized radially so that their respective magnetic poles are distributed on the corresponding inner and outer rings, and the inner ring of the main outer magnetic ring is radially opposite to the outer ring of the main inner magnetic ring and has the same magnetic poles.

[0017] As a further improvement of the present invention, the outer magnetic ring group also includes a secondary outer magnetic ring axially spliced ​​at one end of the main outer magnetic ring, the secondary outer magnetic ring is magnetized axially, and the magnetic pole of the secondary outer magnetic ring close to one end of the main inner magnetic ring is the same as the magnetic pole of the outer ring of the main inner magnetic ring.

[0018] As a further improvement of the present invention, the inner magnetic ring group also includes a secondary inner magnetic ring axially spliced ​​at one end of the main inner magnetic ring, the secondary inner magnetic ring is magnetized radially, and the outer ring of the secondary inner magnetic ring is radially opposite to the other end of the secondary outer magnetic ring and has the same magnetic pole.

[0019] As a further improvement of the present invention, the impeller permanent magnetic suspension bearing includes an outer moving magnetic ring, an inner moving magnetic ring, an outer static magnetic ring and an inner static magnetic ring. The outer moving magnetic ring and the inner moving magnetic ring are both built into the impeller lower cover, and the inner moving magnetic ring is coaxially distributed in the middle of the outer moving magnetic ring; the outer static magnetic ring and the inner static magnetic ring are both built into the lower wall of the pump cavity, and the inner static magnetic ring is coaxially distributed in the middle of the outer static magnetic ring; the outer moving magnetic ring and the inner static magnetic ring, as well as the inner moving magnetic ring and the outer static magnetic ring repel each other, thereby producing a radial constraint and positioning effect on the impeller.

[0020] As a further improvement of the present invention, the outer moving magnetic ring, the inner moving magnetic ring, the outer static magnetic ring and the inner static magnetic ring are all magnetized along the axis, the outer moving magnetic ring and the outer static magnetic ring are axially arranged opposite to each other and the magnetic poles of one end opposite to each other are different, the inner moving magnetic ring and the inner static magnetic ring are axially arranged opposite to each other and the magnetic poles of one end opposite to each other are different, and at the same time, the magnetic pole distributions of the upper and lower ends of the outer moving magnetic ring and the inner moving magnetic ring are opposite, and the magnetic pole distributions of the upper and lower ends of the outer static magnetic ring and the inner static magnetic ring are opposite.

[0021] As a further improvement of the present invention, the impeller permanent magnetic suspension bearing further includes a static magnetic core built into the central cone, and the static magnetic core is coaxially distributed in the middle of the inner moving magnetic ring and repel each other.

[0022] As a further improvement of the present invention, the iron core is provided with a first core portion distributed along the radial direction of the rotor and a second core portion extending vertically downward from an end of the first core portion facing away from the rotor;

[0023] The electrically controlled magnetic core is annular and magnetized in the radial direction. The other ends of the first core parts are arranged opposite to the outer ring of the electrically controlled magnetic core. After being magnetized by the energized coil, the first core parts can generate radial attraction or radial repulsion with the electrically controlled magnetic core.

[0024] The electrically controlled magnetic ring is magnetized in the axial direction, the lower end of the second core is arranged opposite to the electrically controlled magnetic ring, and the second core is magnetized by the energized coil and can generate an axial attraction force or an axial repulsion force with the electrically controlled magnetic ring;

[0025] The magnetic pole of the outer ring of the electrically controlled magnetic core is different from the magnetic pole of the upper end of the electrically controlled magnetic ring.

[0026] As a further improvement of the present invention, there are N electromagnets, and N is an even number greater than or equal to 4; two electromagnets that are centrally symmetrical are combined into an electromagnet group, and the N electromagnets are distributed into N / 2 electromagnet groups. Each electromagnet group can be controlled by an external controller to work independently, and two electromagnets in the same electromagnet group work simultaneously.

[0027] As a further improvement of the present invention, two coils, namely a first coil and a second coil, are wound around the iron core of each electromagnet, and the first coils of the two electromagnets in the same electromagnet group are wound in opposite directions and are connected in series with each other; when any one of the coils of the electromagnet is energized, the other coil on it is de-energized.

[0028] As a further improvement of the present invention, the electromagnetic suspension bearing further includes a circuit board and a plurality of displacement sensors, wherein the plurality of electromagnets and the plurality of displacement sensors are mounted on the circuit board and electrically connected to an external controller via the circuit board;

[0029] The plurality of displacement sensors are arranged one by one beside the plurality of electromagnets and are arranged above and below the electrically controlled magnetic ring, and are used to cooperate with the electrically controlled magnetic ring to detect the position signal of the impeller. The external controller controls the magnitude and direction of the current input to the corresponding electromagnet according to the feedback position signal, so as to drive the rotor impeller back to the center position.

[0030] As a further improvement of the present invention, the blood pump further comprises an auxiliary sliding bearing, the auxiliary sliding bearing comprising a sliding cone and a sliding support surface, the sliding cone being fixedly disposed at the bottom of the rotor, the sliding support surface being fixedly disposed at the top of the central cone, and the sliding cone being supported on the sliding support surface by a spherical head disposed at its lower end;

[0031] Wherein, the sliding cone and the sliding support surface are made of different bioceramic materials.

[0032] As a further improvement of the present invention, the pump head includes an inner tube and an outer tube, and the outer tube is sleeved on the outer side of the inner tube;

[0033] The drive motor includes a stator winding and a rotor magnet, wherein the stator winding is fixed between the inner tube and the outer tube, and the rotor magnet is built into the rotor;

[0034] The pump housing is further provided with a pump upper shell, and the pump upper shell cover is provided on the plurality of electromagnets and is sealedly connected to the inner tube, the outer tube and the pump chamber.

[0035] The beneficial effects of the present invention are:

[0036] 1. The present invention provides a hybrid magnetic levitation centrifugal blood pump. By disposing a set of passive rotor permanent magnetic levitation bearings between the rotor and the pump head, a set of passive impeller permanent magnetic levitation bearings between the impeller and the pump chamber, and a set of active electromagnetic levitation bearings, this hybrid magnetic levitation technology utilizes two sets of smaller permanent magnetic levitation bearings, while only one set of larger electromagnetic levitation bearings is used. This effectively achieves stable suspension of the blood pump with five degrees of freedom, greatly simplifying its structure, reducing its size and weight, making it less invasive to implant, and improving its applicability. Furthermore, the simple structure and compact size of the blood pump also reduce the difficulty of processing and equipment, thereby lowering manufacturing costs.

[0037] 2. The rotor permanent magnetic suspension bearing is provided with a main outer magnetic ring, a main inner magnetic ring, a secondary outer magnetic ring and a secondary inner magnetic ring. The main outer magnetic ring and the main inner magnetic ring are magnetized radially and repel each other; the secondary outer magnetic ring is magnetized axially, so that more magnetic force is concentrated in the center part, and is the same as the end magnetic pole with the shortest path on the main inner magnetic ring, so as to increase the repulsive force between the inner and outer magnetic ring groups; in addition, the secondary inner magnetic ring is magnetized radially, and there is also a radial repulsive force between it and the secondary outer magnetic ring. Under the superposition of several repulsive forces, the radial freedom of the rotor is constrained, so that the rotor obtains a better radial suspension effect; at the same time, the rotor permanent magnetic suspension bearing adopts this arrangement method, which can allow the rotor impeller to float up and down in a larger range, the rotor is not easy to tilt and cause instability, the radial suspension is more stable, and the practicality is stronger;

[0038] 3. The impeller permanent magnetic suspension bearing is provided with an outer moving magnetic ring and an inner moving magnetic ring built into the lower cover of the impeller, and an outer static magnetic ring and an inner static magnetic ring built into the lower wall of the pump chamber. Each moving and static magnetic ring is magnetized along the axial direction, and the inner and outer crossed magnetic poles are reversed, so that the outer moving magnetic ring and the inner static magnetic ring, as well as the inner moving magnetic ring and the outer static magnetic ring, repel each other. In addition, the radial repulsive force generated by the static magnetic core built into the central cone on the inner moving magnetic ring makes the radial suspension effect of the impeller more stable, especially the constraints on the two radial displacement degrees of freedom of the impeller are better;

[0039] 4. The electromagnetic suspension bearing is equipped with an electrically controlled magnetic core built into the rotor, an electrically controlled magnetic ring built into the impeller cover, and several electromagnets. The iron cores of the electromagnets are all L-shaped. When the coil is energized, the iron core is magnetized to generate radial attraction or radial repulsion with the electrically controlled magnetic core, and at the same time, it can generate axial attraction or axial repulsion with the electrically controlled magnetic ring. This can regulate the radial deflection, radial displacement, and axial displacement of the rotor impeller, realizing active control suspension of five degrees of freedom, improving the suspension effect of the rotor impeller, and ensuring stable operation of the blood pump;

[0040] 5. There are an even number of electromagnets, and two electromagnets that are centrally symmetrical form an electromagnet group. Two coils are wound around the iron core of each electromagnet. The first coils of the two electromagnets in the same electromagnet group are wound in opposite directions and are connected in series. They are responsible for regulating the radial deflection and radial displacement of the rotor impeller. The currents of the two first coils connected in series are the same in magnitude but opposite in direction, so that the magnetic field strength generated by the two electromagnets is consistent, the force applied to the rotor impeller will be more balanced, the control effect will be better, and the rotor impeller suspension effect will be improved; the second coil of the electromagnet is responsible for regulating the axial displacement of the rotor impeller;

[0041] 6. The impeller is provided with an impeller upper cover and an impeller lower cover. The impeller upper cover cooperates with the upper wall of the pump chamber to form an upper secondary flow channel, and the impeller lower cover cooperates with the lower wall of the pump chamber to form a lower secondary flow channel. The present invention can control the gap between the upper and lower secondary flow channels to be between 0.3 and 1 mm. The larger the gap, the lower the liquid pressure is several times lower, which can greatly reduce the complications of hemolysis, stroke, and thrombosis caused by high pressure and improve the biosafety of the blood pump. In addition, the upper and lower secondary flow channels have short paths, a fast blood flow rate, and blood is not easily retained. The overall structure of the blood pump is compact, especially the internal structure is simple and smooth, without dead angles, no dynamic sealing problems, and is not prone to thrombosis, thereby further improving the biocompatibility and safety of the blood pump.

[0042] 7. The present invention is also provided with an auxiliary sliding bearing, which serves as an auxiliary bearing and a safety device. When the blood pump is started, it has only one point of support, and the non-surface contact friction helps the rotor impeller to start smoothly. After being suspended, the auxiliary sliding bearing does not need to support the rotation of the rotor impeller for a long time like traditional mechanical bearings, which can reduce mechanical failures of the blood pump caused by mechanical bearing friction, and can also reduce hemolysis and thrombosis complications caused by friction and heat. In addition, the auxiliary sliding bearing can also prevent the rotor impeller from colliding with the lower wall of the pump chamber in abnormal situations such as emergency stop and sudden failure of the blood pump, thereby acting as a safety device to ensure the stability and safety of the blood pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a schematic cross-sectional view of a hybrid magnetic levitation centrifugal blood pump according to the present invention;

[0044] FIG2 is a perspective view of the rotor impeller in the hybrid magnetic levitation centrifugal blood pump of the present invention;

[0045] FIG3 is a perspective view of the rotor impeller of the hybrid magnetic levitation centrifugal blood pump according to the present invention from the bottom perspective;

[0046] FIG4 is a perspective view of a half-cut permanent magnetic suspension bearing of a rotor in a hybrid magnetic suspension centrifugal blood pump according to the present invention;

[0047] FIG5 is a perspective view of an electromagnet and a displacement sensor in a hybrid magnetic levitation centrifugal blood pump according to the present invention mounted on a PCB;

[0048] FIG6 is a perspective view of another embodiment of the hybrid magnetic levitation centrifugal blood pump of the present invention in which the electromagnet and the displacement sensor are mounted on a PCB board;

[0049] FIG7 is a cross-sectional schematic diagram of the electrically controlled radial deflection force of the rotor impeller of the hybrid magnetic levitation centrifugal blood pump of the present invention;

[0050] FIG8 is a cross-sectional schematic diagram of the electrically controlled axial displacement of the rotor impeller of the hybrid magnetic levitation centrifugal blood pump of the present invention;

[0051] FIG9 is a cross-sectional schematic diagram of the forces acting on the rotor impeller of the hybrid magnetic levitation centrifugal blood pump of the present invention when the pump is in operation;

[0052] The arrows in FIG4 indicate the directions of the magnetic lines of force, and the force arrows in FIG7 to FIG9 indicate the directions of the forces acting on the rotor impeller 2 .

[0053] In conjunction with the accompanying drawings, the following explanations are given: 1. Pump casing; 11. Pump head; 111. Inner tube; 112. Outer tube; 12. Pump chamber; 121. Upper secondary flow channel; 122. Lower secondary flow channel; 13. Center cone; 14. Pump upper casing; 2. Rotor impeller; 21. Rotor; 22. Impeller; 221. Blades; 2211. Long blades; 2212. Short blades; 222. Impeller upper cover; 2220. Upper cover hole; 223. Impeller lower cover; 2230. Lower cover hole; 224. Inlet; 225. Backflow port; 3. Drive motor; 31. Stator winding; 32. Rotor magnet; 4. Rotor permanent magnetic suspension bearing; 41. Main outer magnetic ring; 42. Main Inner magnetic ring; 43. Auxiliary outer magnetic ring; 44. Auxiliary inner magnetic ring; 5. Impeller permanent magnetic suspension bearing; 51. Outer dynamic magnetic ring; 52. Inner dynamic magnetic ring; 53. Outer static magnetic ring; 54. Inner static magnetic ring; 55. Static magnetic core; 6. Electromagnetic suspension bearing; 61. Electric controlled magnetic core; 62. Electric controlled magnetic ring; 63. Electromagnet; 631. Iron core; 6311. First core part; 6312. Second core part; 632. Coil; 64. Circuit board; 65. Displacement sensor; 7. Auxiliary sliding bearing; 71. Sliding cone; 72. Sliding support surface. DETAILED DESCRIPTION

[0054] A preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0055] 1 to 5 , the present invention provides a hybrid magnetic levitation centrifugal blood pump, comprising: a pump housing 1 , a rotor impeller 2 , a drive motor 3 , a rotor permanent magnetic levitation bearing 4 , an impeller permanent magnetic levitation bearing 5 , an electromagnetic levitation bearing 6 and an auxiliary sliding bearing 7 .

[0056] The pump housing 1 is provided with a pump head 11, a pump chamber 12 and a pump upper shell 14. The pump head 11 is vertically connected to the top of the pump chamber 12, and the outer diameter of the pump head 11 is smaller than the outer diameter of the pump chamber 12. The pump head 11 includes an inner tube 111 and an outer tube 112, and the outer tube 112 is sleeved on the outside of the inner tube 111. The pump upper shell 14 is installed on the top of the pump chamber 12 and is sealed and fixedly connected to the pump chamber 12, the inner tube 111 and the outer tube 112. Among them, a central cone 13 protruding into the cavity is provided in the middle of the lower wall of the pump chamber 12.

[0057] The rotor impeller 2 includes a rotor 21 and an impeller 22. The rotor 21 is inserted into the inner tube 111, and the impeller 22 is built into the pump chamber 12. The rotor 21 and the impeller 22 are fixedly connected as a whole and supported on the central cone 13, and do not contact the lower wall of the pump chamber 12.

[0058] The drive motor 3 includes a stator winding 31 and a rotor magnet 32. The stator winding 31 is fixed between the inner tube 111 and the outer tube 112. The rotor magnet 32 ​​is embedded in the middle section of the rotor 21 and is arranged radially opposite the stator winding 31. Blood flows into the pump chamber 12 through the upper port of the inner tube 111. The drive motor 3 drives the rotor 21, which drives the impeller 22 to rotate and produce work. The centrifugal force of the impeller 22 pushes the blood out of the outlet of the pump chamber 12.

[0059] The rotor impeller 2 has a total of six degrees of freedom, namely: radial forward and backward displacement, radial left and right displacement, radial forward and backward deflection, radial left and right deflection, axial up and down displacement and rotation around the central axis. Among them, the first five degrees of freedom need to be constrained and controlled, which are called "five degrees of freedom". The sixth degree of freedom is the rotational freedom of the rotor impeller 2, which does not need to be constrained and cannot be constrained.

[0060] In the present invention, the rotor permanent magnetic suspension bearing 4 is used to constrain the radial freedom of the rotor 21. The rotor permanent magnetic suspension bearing 4 is arranged at the upper end of the rotor 21 and in the pump head 11. The rotor 21 can be radially centered under the action of the rotor permanent magnetic suspension bearing 4. The specific method is as follows.

[0061] Referring to Figures 1 and 4, the rotor permanent magnetic suspension bearing 4 includes an outer magnetic ring group and an inner magnetic ring group. The outer magnetic ring group is built into the pump head 11, between the inner tube 111 and the outer tube 112. The inner magnetic ring group is built into the upper end of the rotor 21 and coaxially distributed in the center of the outer magnetic ring group. The outer magnetic ring group includes a main outer magnetic ring 41, and the inner magnetic ring group includes a main inner magnetic ring 42. The main outer magnetic ring 41 and the main inner magnetic ring 42 are both magnetized radially so that their respective magnetic poles are distributed on the corresponding inner and outer rings. The outer ring of the main inner magnetic ring 42 is radially opposite to the inner ring of the main outer magnetic ring 41 and has the same magnetic poles. As a result, the main outer magnetic ring 41 can generate a radial repulsive force on the main inner magnetic ring 42, and the upper end of the rotor 21 is radially centered under the action of this radial repulsive force.

[0062] Furthermore, the outer magnetic ring group also includes a secondary outer magnetic ring 43 axially spliced ​​to the upper end of the main outer magnetic ring 41. The secondary outer magnetic ring 43 is axially magnetized so that its magnetic poles are distributed at the upper and lower ends, and the magnetic poles of the lower end of the secondary outer magnetic ring 43 close to the main inner magnetic ring 42 are the same as the magnetic poles of the outer ring of the main inner magnetic ring 42, so that the secondary outer magnetic ring 43 can also generate a repulsive force on the main inner magnetic ring 42. The present invention provides a secondary outer magnetic ring 43, and the secondary outer magnetic ring 43 is axially magnetized, so that more magnetic force is concentrated in the center. The magnetic force in the center is stronger, and the interaction force between the secondary outer magnetic ring 43 and the main inner magnetic ring 42 is greater. At the same time, the secondary outer magnetic ring 43 has the same magnetic poles as the end of the shortest path on the main inner magnetic ring 42, and the repulsive force generated is greater, thereby further improving the radial suspension effect of the rotor 21.

[0063] In addition, the inner magnetic ring group also includes a secondary inner magnetic ring 44 axially spliced ​​to the upper end of the main inner magnetic ring 42. The secondary inner magnetic ring 44 is magnetized radially, and its magnetic poles are distributed on the inner and outer rings. The outer ring of the secondary inner magnetic ring 44 is radially opposite to the upper end of the secondary outer magnetic ring 43 and has the same magnetic poles, so that the secondary outer magnetic ring 43 can also generate a radial repulsive force on the secondary inner magnetic ring 44, thereby playing an auxiliary suspension role. Under the superposition of several repulsive forces, the rotor 21 obtains a better radial suspension effect.

[0064] The main inner magnetic ring 42 and the auxiliary inner magnetic ring 44 have the same inner and outer diameters, and the main outer magnetic ring 41 and the auxiliary outer magnetic ring 43 have the same inner and outer diameters. Each of the main outer magnetic ring 41, the main inner magnetic ring 42, the auxiliary outer magnetic ring 43, and the auxiliary inner magnetic ring 44 can be integral or composed of multiple permanent magnets.

[0065] As a preferred embodiment, the thickness of the inner magnetic ring group is consistent with that of the outer magnetic ring group. This configuration ensures more stable suspension and is less prone to tilting instability. Furthermore, the thickness of the secondary inner magnetic ring 44 is half that of the secondary outer magnetic ring 43, ensuring that the outer magnetic pole of the secondary inner magnetic ring 44 can align with the upper magnetic pole of the secondary outer magnetic ring 43, generating radial repulsion. In this embodiment, the thickness ratio of the secondary inner magnetic ring 44 to the primary inner magnetic ring 42 is 1:5, and the thickness ratio of the secondary outer magnetic ring 43 to the primary outer magnetic ring 41 is 2:4.

[0066] By adopting the above arrangement, the rotor permanent magnetic suspension bearing 4 of the present invention can allow the rotor impeller 2 to float up and down in a larger range. Within the allowable floating range (up to 0.5 mm or more), the rotor impeller 2 is not prone to instability, the radial suspension is more stable, and the practicality is stronger.

[0067] Furthermore, the present invention can also bias the inner magnetic ring group downward compared to the outer magnetic ring group, so that the outer magnetic ring group can also generate a downward axial repulsive force on the inner magnetic ring group. Under the action of this axial repulsive force, the rotor impeller 2 is supported on the center cone 13 to ensure smooth starting of the rotor impeller 2.

[0068] As shown in Figure 4, in this embodiment, the outer ring of the main inner magnetic ring 42 is an N pole and the inner ring is an S pole, the outer ring of the secondary inner magnetic ring 44 is an S pole and the inner ring is an N pole, the outer ring of the main outer magnetic ring 41 is an S pole and the inner ring is an N pole, and the upper end of the secondary outer magnetic ring 43 is an S pole and the lower end is an N pole.

[0069] In another embodiment of the present invention, the N poles of all magnetic rings in the rotor permanent magnetic bearing 4 are reversed to S poles, and the S poles are reversed to N poles.

[0070] In the present invention, the impeller permanent magnetic suspension bearing 5 is used to constrain the radial freedom of the impeller 22. The impeller permanent magnetic suspension bearing 5 is arranged on the impeller lower cover 223 and the lower wall of the pump chamber 12. The impeller 22 can be radially centered under the force of the impeller permanent magnetic suspension bearing 5. The specific method is as follows.

[0071] Referring to Figure 1 , the impeller permanent magnetic suspension bearing 5 includes an outer moving magnetic ring 51, an inner moving magnetic ring 52, an outer static magnetic ring 53, and an inner static magnetic ring 54. Both the outer moving magnetic ring 51 and the inner moving magnetic ring 52 are coaxially located within the impeller lower cover 223. The inner moving magnetic ring 52 is coaxially located at the center of the outer moving magnetic ring 51 and has a uniform thickness. Both the outer static magnetic ring 53 and the inner static magnetic ring 54 are coaxially located in the center of the pump cavity 12. The lower wall of the pump cavity 12 adopts a double-layer structure, with a sealed accommodating cavity formed in the middle for accommodating the outer static magnetic ring 53 and the inner static magnetic ring 54. The inner static magnetic ring 54 is coaxially located in the middle of the outer static magnetic ring 53 and has a uniform thickness. The outer moving magnetic ring 51 and the inner static magnetic ring 54, as well as the inner moving magnetic ring 52 and the outer static magnetic ring 53, repel each other, thereby exerting a radial constraint and positioning effect on the impeller 22.

[0072] Specifically, the outer moving magnetic ring 51, inner moving magnetic ring 52, outer static magnetic ring 53, and inner static magnetic ring 54 are all magnetized along the axis, with their respective magnetic poles distributed at their upper and lower ends. The outer moving magnetic ring 51 and the outer static magnetic ring 53 are axially opposed to each other and have different magnetic poles on their opposing ends. The inner moving magnetic ring 52 and the inner static magnetic ring 54 are axially opposed to each other and have different magnetic poles on their opposing ends. Furthermore, the magnetic pole distributions at the upper and lower ends of the outer moving magnetic ring 51 and the inner moving magnetic ring 52 are opposite, while the magnetic pole distributions at the upper and lower ends of the outer static magnetic ring 53 and the inner static magnetic ring 54 are opposite. In other words, the magnetic poles at the lower end of the outer moving magnetic ring 51 are the same as the magnetic poles at the upper end of the inner static magnetic ring 54, and the magnetic poles at the upper end of the outer static magnetic ring 53 are the same as the magnetic poles at the lower end of the inner moving magnetic ring 52. Consequently, mutual repulsion occurs between the outer moving magnetic ring 51 and the inner static magnetic ring 54, as well as between the inner moving magnetic ring 52 and the outer static magnetic ring 53, keeping the impeller 22 radially centered due to the repulsive force.

[0073] Since the outer moving magnetic ring 51 and the outer static magnetic ring 53 have different magnetic poles, and the inner moving magnetic ring 52 and the inner static magnetic ring 54 have different magnetic poles, the outer static magnetic ring 53 has a downward axial suction force on the outer moving magnetic ring 51, and the inner static magnetic ring 54 has a downward axial suction force on the inner moving magnetic ring 52. The rotor impeller 2 is supported on the center cone 13 under the action of this axial suction force, further ensuring the smooth start-up of the rotor impeller 2.

[0074] In addition, the impeller permanent magnetic suspension bearing 5 also includes a static magnetic core 55 fixedly built into the central cone 13. The static magnetic core 55 is coaxially distributed in the middle part of the inner moving magnetic ring 52. The magnetization direction of the static magnetic core 55 is also axial. The magnetic poles at its upper and lower ends are the same as the magnetic poles at the upper and lower ends of the inner moving magnetic ring 52, that is, the magnetic poles at the upper end of the static magnetic core 55 are radially opposite to and repel each other with the magnetic poles at the upper end of the inner moving magnetic ring 52, and the magnetic poles at the lower end of the static magnetic core 55 are radially opposite to and repel each other with the magnetic poles at the lower end of the inner moving magnetic ring 52, so that the static magnetic core 55 produces a radial repulsive force on the inner moving magnetic ring 52, and further produces a better radial constraint and positioning effect on the impeller 22. In addition, the radial constraint effect of the outer moving magnetic ring 51 and the inner static magnetic ring 54, as well as the outer static magnetic ring 53 and the inner moving magnetic ring 52, makes the radial suspension effect of the impeller 22 more stable, especially the constraint on the two radial displacement degrees of freedom of the impeller 22 is better.

[0075] Among them, the static magnetic core 55 is much larger than the thickness of the inner moving magnetic ring 52. After the rotor impeller 2 is suspended, it is ensured that the magnetic poles at the upper end of the static magnetic core 55 can still be radially opposite to the magnetic poles at the upper end of the inner moving magnetic ring 52, and the magnetic poles at the lower end of the static magnetic core 55 can still be radially opposite to the magnetic poles at the lower end of the inner moving magnetic ring 52.

[0076] As shown in FIG1 , in this embodiment, the outer moving magnetic ring 51 and the outer static magnetic ring 53 both have their S poles at the top and their N poles at the bottom, while the inner moving magnetic ring 52 and the inner static magnetic ring 54 both have their N poles at the top and their S poles at the bottom. For example, when the impeller 22 deflects radially to the left, the rightward repulsive force exerted by the outer static magnetic ring 53 on the inner moving magnetic ring 52 increases on the left side. Simultaneously, the attraction of the outer static magnetic ring 53 on the outer moving magnetic ring 51, and the attraction of the inner static magnetic ring 54 on the inner moving magnetic ring 52, both have rightward components. Similarly, on the right side, the rightward repulsive force exerted by the inner static magnetic ring 54 on the outer moving magnetic ring 51 increases. Simultaneously, the attraction of the outer static magnetic ring 53 on the outer moving magnetic ring 51, and the attraction of the inner static magnetic ring 54 on the inner moving magnetic ring 52, both have rightward components. These forces act together on the impeller 22, forcing the impeller 22 to the right to its center, where it is in a state of force equilibrium.

[0077] In other embodiments of the present invention, the N poles of all permanent magnets in the impeller permanent magnetic bearing 5 may be reversed to S poles, and vice versa.

[0078] 1 and 5 , the electromagnetic suspension bearing 6 is an active suspension bearing, which is used to actively correct the deflection and displacement of the rotor impeller 2 , specifically in the following manner.

[0079] The electromagnetic bearing 6 comprises an electrically controlled magnetic core 61, an electrically controlled magnetic ring 62, and several electromagnets 63. The electrically controlled magnetic ring 62 is fixedly mounted within the impeller upper cover 222. The electrically controlled magnetic core 61 is positioned near the lower end of the rotor 21. The electromagnets 63 are positioned at the top of the pump chamber 12, within the pump upper casing 14, and are distributed in a circular pattern with equal spacing around the inner tube 111. The electromagnets 63 comprise an L-shaped iron core 631 and a coil 632 wound around the iron core 631. The ends of the iron core 631 are positioned opposite the electrically controlled magnetic core 61 and the electrically controlled magnetic ring 62, respectively.

[0080] Specifically, the iron core 631 comprises a first core portion 6311 extending radially along the rotor 21, and a second core portion 6312 extending vertically downward from the end of the first core portion 6311 facing away from the rotor 21. The electrically controlled magnetic core 61 is annular and magnetized radially, with its magnetic poles distributed on the inner and outer rings. The other end of the first core portion 6311, facing the rotor 21, is positioned opposite the outer ring of the electrically controlled magnetic core 61. When energized, the coil 632 magnetizes the iron core 631, generating radial attraction or repulsion between the first core portion 6311 and the electrically controlled magnetic core 61, thereby constraining the radial freedom of the rotor impeller 2. The electrically controlled magnetic ring 62 is magnetized along the axial direction so that its magnetic poles are distributed at the upper and lower ends; the lower end of the second core 6312 is arranged opposite to the electrically controlled magnetic ring 62, and when the coil 632 is energized, the iron core 631 is magnetized, so that the second core 6312 and the electrically controlled magnetic ring 62 generate axial attraction or axial repulsion, thereby constraining the axial freedom of the rotor impeller 2.

[0081] It can be seen that the present invention adopts a set of electromagnetic suspension bearings 6 to regulate the radial deflection, radial displacement and axial displacement of the rotor impeller 2 through electromagnetic repulsive force or attractive force, thereby realizing active control suspension of five degrees of freedom, improving the suspension effect of the rotor impeller 2, ensuring the stable operation of the blood pump, and at the same time simplifying the blood pump structure and reducing the volume of the blood pump.

[0082] Please refer to Figure 1 again. The magnetic poles of the outer ring of the electrically controlled magnetic core 61 are different from the magnetic poles of the upper end of the electrically controlled magnetic ring 62. Specifically, in this embodiment, the upper end of the electrically controlled magnetic ring 62 is the S pole and the lower end is the N pole, and the outer ring of the electrically controlled magnetic core 61 is the N pole and the inner ring is the S pole.

[0083] Of course, in other embodiments, the S poles of the electrically controlled magnetic ring 62 and the electrically controlled magnetic core 61 may be reversed to N poles, and the N poles of the electrically controlled magnetic ring 62 and the electrically controlled magnetic core 61 may be reversed to S poles.

[0084] Continuing with Figures 1 and 5 , the electromagnetic bearing 6 also includes a circuit board 64 and a plurality of displacement sensors 65 . These sensors 65 are arranged one-to-one alongside the electromagnets 63 . The circuit board 64 is annular and affixed to the top of the pump chamber 12 and also located within the pump upper housing 14 . The electromagnets 63 and displacement sensors 65 are mounted on the circuit board 64 and electrically connected to an external controller via the circuit board 64 . The displacement sensors 65 are arranged on the side of the second core 6312 facing away from the rotor 21 and are positioned above and below the electrically controlled magnetic ring 62 .

[0085] In this embodiment, the displacement sensor 65 is a Hall sensor, which is used in conjunction with the electrically controlled magnetic ring 62 to detect the magnetic field strength in the suspension gap between the top of the impeller 22 and the pump chamber 12. When the rotor impeller 2 deviates, the displacement sensor 65 detects the position signal of the rotor impeller 2 according to the change in magnetic field strength, and feeds the position signal back to the external controller. The external controller controls the magnitude and direction of the current input to the corresponding electromagnet 63 according to the position signal, and uses the force between the iron core 631, the electrically controlled magnetic ring 62 and the electrically controlled magnetic core 61 to drive the rotor impeller 2 back to the center position.

[0086] Furthermore, the present invention has N electromagnets 63 , and N is an even number greater than or equal to 4. Correspondingly, N displacement sensors 65 are also configured.

[0087] Referring to FIG. 5 , in this embodiment, the number of electromagnets 63 is preferably eight.

[0088] Referring to FIG. 6 , optionally, in another embodiment of the present invention, there are six electromagnets 63 .

[0089] It can be understood that, under permitted conditions, the greater the number of electromagnets 63 , the better the control effect on the rotor impeller 2 .

[0090] Two electromagnets 63, arranged symmetrically around the center, form an electromagnet group. The eight electromagnets 63 are divided into four groups. Each group operates independently, controlled by an external controller. Two electromagnets 63 in the same group operate simultaneously. When the rotor impeller 2 deviates in one degree of freedom, only the corresponding electromagnet group or groups need to be activated.

[0091] It's worth noting that each electromagnet 63 has two coils 632 wound around its core 631: a first coil and a second coil. The first coils of the two electromagnets 63 in the same electromagnet group are wound in opposite directions and connected in series. The currents in the two series-connected first coils are equal in magnitude and opposite in direction, resulting in a consistent magnetic field strength generated by the two electromagnets 63. This results in a more balanced force on the rotor impeller 2, better control, and improved levitation of the rotor impeller 2.

[0092] The first coil is responsible for regulating the radial deflection and radial displacement of the rotor impeller 2, while the second coil is responsible for regulating the axial displacement of the rotor impeller 2. The first coils of the two electromagnets 63 in the same electromagnet group are wound in the same direction and can be connected in series or not. It should be noted that when one coil 632 of an electromagnet 63 is energized, the other coil 632 above it is de-energized.

[0093] The following is a detailed explanation using the offset of two degrees of freedom as an example.

[0094] Referring to FIG7 , when the blood pump is operating, the rotor impeller 2 deflects and tilts radially to the right, with the upper end of the rotor 21 to the right and the lower end to the left. The impeller 22 is higher on the left and lower on the right. The displacement sensor 65 quickly detects the position signal of the deflection of the electrically controlled magnetic ring 62 and the impeller 22. The position signal is fed back and amplified by power and transmitted to the controller. The controller then applies appropriate control current to the first coils of the two electromagnets 63 in the electromagnet group shown in FIG7 . The currents in the first coils of the two electromagnets 63 are equal in magnitude and opposite in direction. The downward end magnetic pole of the iron core 631 of the left electromagnet 63 is the S pole, which can generate an axial downward thrust (repulsive force) F1 on the left higher S pole of the electric-controlled magnetic ring 62. The downward end magnetic pole of the iron core 631 of the right electromagnet 63 is the N pole, which can generate an axial upward pulling force (attractive force) F2 on the right lower S pole of the electric-controlled magnetic ring 62. The two forces F1 and F2 are equal in magnitude and opposite in direction. They apply a force to the impeller 22 through the electric-controlled magnetic ring 62 to correct the impeller 22. At the same time, the other magnetic pole of the iron core 631 of the left electromagnet 63 is the N pole, which can generate a radial thrust F3 on the N pole of the outer ring of the electro-controlled magnetic core 61 that is biased to the left; the other magnetic pole of the iron core 631 of the right electro-magnet 63 is the S pole, which can generate a radial pulling force F4 on the N pole of the outer ring of the electro-controlled magnetic core 61 that is biased to the left. F3 and F4 are in the same direction, and the rotor 21 is applied with force through the electro-controlled magnetic core 61 to correct the deviation of the rotor 21. F1, F2, F3 and F4 act together on the rotor impeller 2 until the corrected rotor impeller 2 returns to the center position and the electromagnet 63 is de-energized. This group of electromagnets has a control effect on the radial deflection and radial displacement of the rotor impeller 2, and can play a good restraining role in all four radial degrees of freedom.

[0095] Referring to FIG8 , when the blood pump is working, if the rotor impeller 2 is subjected to a large axial force, axial displacement will occur and it is prone to violent oscillation. As shown in FIG8 , the rotor impeller 2 is displaced upward as a whole. At this time, the displacement sensor 65 detects the position signal of the axial displacement of the electrically controlled magnetic ring 62 and the impeller 22. The position signal is transmitted to the controller through feedback and power amplification. The controller then gives appropriate control current to the second coils of the two electromagnets 63 in the electromagnet group shown in FIG8 . The current directions of the second coils of the two electromagnets 63 are the same. The downward magnetic poles of the iron cores 631 of the two electromagnets 63 are both S poles, which generate an axial downward thrust (repulsive force) F5 on the S pole of the electrically controlled magnetic ring 62 until the rotor impeller 2 is pushed to the suspended axial set position, and then the electromagnet 63 is de-energized. At the same time, the other magnetic poles of the iron cores 631 of the two electromagnets 63 pointing to the radial center are both N poles, which repel each other with the N poles of the outer ring of the electrically controlled magnetic core 61. If the rotor impeller 2 is at the radial center position, the repulsive forces F6 of the two electromagnets 63 on the electrically controlled magnetic core 61 cancel each other out, and the resultant force is 0, which is in a state of force balance. If the rotor impeller 2 deflects, the repulsive forces F6 of the two electromagnets 63 on the electrically controlled magnetic core 61 are unbalanced. Since the magnitude of the force is inversely proportional to the square of the distance, the repulsive force on the side closer to the deflection is greater, and the repulsive force on the side farther away is smaller. The rotor 21 will be pushed toward the radial center position by the large repulsive force, returning to a state of balance. Therefore, this electromagnet group can control the radial deflection while regulating the axial displacement of the rotor impeller 2.

[0096] It should be noted that when the blood pump is working, the rotor impeller 2 often has multi-degree-of-freedom displacement and deflection. For example, the rotor impeller 2 deflects radially to the left and right and displaces axially. At this time, the controller gives the first coils of the two electromagnets 63 in the corresponding group of electromagnet groups an appropriate control current to correct the radial left and right deflection, and gives the second coils of one or more groups of electromagnet groups other than the group of electromagnet groups an appropriate control current to correct the axial displacement.

[0097] Referring to Figures 1 to 3, the impeller 22 is a closed-loop impeller, comprising an upper impeller cover 222, a lower impeller cover 223, and a plurality of blades 221 distributed around its central axis. Both the upper impeller cover 222 and the lower impeller cover 223 are annular and have the same outer diameter. The upper impeller cover 222 is fixedly connected to the tops of the blades 221, and the upper impeller cover 222 and the upper wall of the pump chamber 12 form an upper secondary flow channel 121. The upper secondary flow channel 121 communicates with the interior of the impeller 22 via an inlet 224 provided in the upper impeller cover 222. The lower impeller cover 223 is fixedly connected to the bottoms of the blades 221, and the lower impeller cover 223 and the lower wall of the pump chamber 12 form a lower secondary flow channel 122. The lower secondary flow channel 122 communicates with the interior of the impeller 22 via a recirculation port 225 provided in the lower impeller cover 223.

[0098] The middle portion of the impeller upper cover 222 is provided with an upper cover hole 2220. The lower end of the rotor 21 extends through the upper cover hole 2220 to the middle portion of the impeller 22 and is fixedly connected to the blades 221. The inlet 224 is formed by the gap between the impeller upper cover 222 and the rotor 21. The middle portion of the impeller lower cover 223 is provided with a lower cover hole 2230. The aperture of the lower cover hole 2230 is smaller than that of the upper cover hole 2220. The upper end of the center cone 13 extends through the lower cover hole 2230 to the middle portion of the impeller 22. The gap between the impeller lower cover 223 and the center cone 13 forms the reverse flow port 225, and the area of ​​the reverse flow port 225 is much smaller than that of the inlet 224.

[0099] When the blood pump is operating, the centrifugal force of impeller 22 propels blood flow, causing the pressure near the periphery of pump chamber 12 to be greater than the pressure at the center. Under this pressure differential, the upper secondary flow channel 121 flows back toward the center through inlet 224, generating a downward hydraulic thrust F8. Meanwhile, the lower secondary flow channel 122 flows back toward the center through reflow port 225, generating an upward hydraulic thrust F7. Because the area of ​​reflow port 225 is much smaller than that of inlet 224, according to Bernoulli's principle, the flow rate in the lower secondary flow channel 122 is low and the pressure is high, while the flow rate in the upper secondary flow channel 121 is high and the pressure is low. Therefore, when the blood pump is operating at high speed, the upward hydraulic thrust F7 is much greater than the downward hydraulic thrust F8. This dual hydraulic dynamic pressure assists in suspending the impeller 22, providing the thrust for its upward buoyancy.

[0100] Existing suspended blood pumps utilize a permanent magnetic suspension plus hydraulic dynamic pressure suspension mechanism, where hydraulic dynamic pressure is the primary operating mechanism. The dynamic pressure gap is approximately 0.1 mm, resulting in high hydraulic pressure, which can easily lead to complications such as hemolysis, stroke, and thromboembolism. The dual-hydraulic dynamic pressure structure employed in this application, however, only serves as an auxiliary suspension balance mechanism and is not the primary support or operating mechanism. Suspension balance primarily relies on the electromagnetic suspension bearing 6. The gap between the upper secondary flow channel 121 and the lower secondary flow channel 122 of the present invention can be controlled to between 0.3 and 1 mm. This larger gap allows for several times lower hydraulic pressure, significantly reducing complications such as hemolysis, stroke, and thrombosis caused by high pressure, and improving the biosafety of the blood pump.

[0101] In this embodiment, the impeller 22 is provided with, but not limited to, six blades 221. The six blades 221 can be straight blades distributed radially or curved blades. The six blades 221 are equally divided into three long blades 2211 and three short blades 2212. The three long blades 2211 and the three short blades 2212 are staggered in the circumferential direction. The long blades 2211 are fixedly connected to the lower end of the rotor 21, and the ends of the short blades 2212 pointing toward the central axis do not contact the rotor 21. This configuration can increase the operating efficiency of the impeller 22.

[0102] Optionally, in another embodiment of the present invention, the impeller 22 is provided with eight blades 221 .

[0103] Referring to Figure 1 , auxiliary sliding bearing 7 includes a sliding cone 71 and a sliding support surface 72. Sliding cone 71 is fixed to the bottom of rotor 21, while sliding support surface 72 is fixed to the top of center cone 13. Sliding cone 71 is supported on sliding support surface 72 via a spherical head at its lower end. Sliding cone 71 and sliding support surface 72 are made of different bioceramic materials. Optionally, sliding cone 71 may be made of zirconium oxide, and sliding support surface 72 may be made of silicon carbide; alternatively, sliding cone 71 may be made of aluminum oxide, and sliding support surface 72 may be made of silicon carbide.

[0104] The auxiliary sliding bearing 7 serves as both an auxiliary bearing and a safety device. During blood pump startup, it provides single-point support, utilizing non-contact friction to help the rotor impeller 2 start smoothly. Once suspended, the auxiliary sliding bearing 7 no longer requires the long-term rotational support of the rotor impeller 2 required by traditional mechanical bearings. This reduces mechanical failures of the blood pump caused by mechanical bearing friction, as well as hemolysis and thrombotic complications caused by friction and heat. Furthermore, the auxiliary sliding bearing 7 prevents the rotor impeller 2 from colliding with the lower wall of the pump chamber 12 during abnormal conditions such as sudden stop or failure of the blood pump, acting as a safety device and enhancing the stability and safety of the blood pump.

[0105] In the present invention, the pump housing 1 and the rotor impeller 2 are both made of medical titanium alloy material.

[0106] The forces acting on the rotor impeller 2 during operation of the blood pump of the present invention are described in detail below.

[0107] When analyzing the axial force acting on the rotor impeller 2, the position and shape of the blood pump will change with the human body, making the gravity direction of the rotor impeller 2 relative to the blood pump random. In addition, the rotor impeller 2 has a light gravity and is a weak influencing factor. The disturbance caused by gravity can be completely overcome by the resultant forces, so the influence of gravity can be ignored.

[0108] When the blood pump is in a stationary state, the rotor impeller 2 is subjected to three downward forces, namely: the axial magnetic pressure F13 generated by the rotor permanent magnetic suspension bearing 4, the outer magnetic attraction force F9 and the inner magnetic attraction force F10 generated by the impeller permanent magnetic suspension bearing 5, and an upward force, which is the static attraction F11 of the iron core 631 of the electromagnet 63 on the electric control magnetic ring 62.

[0109] Referring to FIG9 , when the blood pump is in operation, the rotor impeller 2 is subjected to axial forces F9, F10, F11, and F13, as well as the following: fluid impulse F16, hydraulic upward thrust F7, hydraulic downward thrust F8, and axial force F12 generated by the electromagnetic bearing 6. The axial force F12 is an electrically adjustable force designed to counteract and balance the other axial forces to ensure that the total axial force is zero.

[0110] In addition to the radial repulsive force F13 generated by the rotor permanent magnetic suspension bearing 4 and the radial repulsive force F14 generated by the impeller permanent magnetic suspension bearing 5, the rotor impeller 2 is also subjected to a radial force F15 generated by the electromagnetic suspension bearing 6. The radial force F15 is an electrically controlled and adjustable force that pushes the rotor impeller 2 to the center. When the rotor impeller 2 is suspended in the center, the forces are balanced to ensure that the total radial force is 0.

[0111] In the above description, many specific details are set forth in order to fully understand the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A hybrid magnetic levitation centrifugal blood pump, characterized in that: include: A pump housing (1) is provided with a pump head (11) and a pump chamber (12), wherein the pump head (11) is vertically connected to the top of the pump chamber (12), and a central cone (13) protruding into the chamber is provided in the middle of the lower wall of the pump chamber (12); A rotor impeller (2), comprising a rotor (21) penetrating the pump head (11) and an impeller (22) built into the pump chamber (12); the rotor (21) and the impeller (22) are fixedly connected as a whole and supported on the central cone (13); the impeller (22) is provided with a plurality of blades (221) distributed around its central axis, an impeller upper cover (222) fixedly connected to the tops of the plurality of blades (221), and an impeller lower cover (223) fixedly connected to the bottoms of the plurality of blades (221); the impeller upper cover (222) is connected to the pump chamber The upper wall clearance of the impeller (12) is matched to form an upper secondary flow channel (121), and the upper secondary flow channel (121) is connected to the interior of the impeller (22) through an inlet (224) provided on the impeller upper cover (222); the impeller lower cover (223) and the lower wall clearance of the pump chamber (12) are matched to form a lower secondary flow channel (122), and the lower secondary flow channel (122) is connected to the interior of the impeller (22) through a reverse flow port (225) provided on the impeller lower cover (223), and the area of ​​the reverse flow port (225) is smaller than the area of ​​the inlet port (224); A driving motor (3) for driving the rotor (21) to drive the impeller (22) to rotate; A rotor permanent magnetic suspension bearing (4) is arranged at the upper end of the rotor (21) and in the pump head (11), and the rotor (21) can be radially centered under the action of the rotor permanent magnetic suspension bearing (4); The impeller permanent magnetic suspension bearing (5) is arranged on the impeller lower cover (223) and the lower wall of the pump chamber (12), and the impeller (22) can be on the impeller permanent magnetic suspension shaft radially centered under the force of bearing (5); An electromagnetic suspension bearing (6) comprises an electrically controlled magnetic core (61) fixed to the rotor (21), an electrically controlled magnetic ring (62) fixed to the impeller upper cover (222), and a plurality of electromagnets (63), wherein the plurality of electromagnets (63) are arranged at the top of the pump chamber (12) and are distributed in a ring-shaped manner with equal spacing around the rotor (21), wherein the electromagnets (63) comprise an L-shaped iron core (631) and a coil (632) wound around the iron core (631), and the two ends of the iron core (631) are respectively arranged opposite to the electrically controlled magnetic core (61) and the electrically controlled magnetic ring (62).

2. The hybrid magnetic levitation centrifugal blood pump according to claim 1, characterized in that: An upper cover hole (2220) is provided in the middle of the impeller upper cover (222); the lower end of the rotor (21) passes through the upper cover hole (2220) and extends to the middle of the impeller (22) and is fixedly connected to the blade (221); the inlet (224) is formed by a gap between the impeller upper cover (222) and the rotor (21); A lower cover hole (2230) is provided in the middle of the impeller lower cover (223), and the upper end of the central cone (13) extends through the lower cover hole (2230) to the middle of the impeller (22), and the backflow port (225) is formed by the gap between the impeller lower cover (223) and the central cone (13).

3. The hybrid magnetic levitation centrifugal blood pump according to claim 1, characterized in that: The plurality of blades (221) are equally divided into a plurality of long blades (2211) and a plurality of short blades (2212); the plurality of long blades (2211) and the plurality of short blades (2212) are distributed alternately and at intervals in a circumferential direction; the long blades (2211) are all fixedly connected to the lower end of the rotor (21); and the ends of the short blades (2212) pointing to the central axis are not in contact with the rotor (21).

4. The hybrid magnetic levitation centrifugal blood pump according to claim 1, characterized in that: The rotor permanent magnetic suspension bearing (4) comprises an outer magnetic ring group and an inner magnetic ring group, wherein the outer magnetic ring group is built into the pump head (11), and the inner magnetic ring group is built into the upper end of the rotor (21) and coaxially distributed in the middle of the outer magnetic ring group; the outer magnetic ring group comprises a main outer magnetic ring (41), and the inner magnetic ring group comprises a main inner magnetic ring (42), the main outer magnetic ring (41) and the main inner magnetic ring (42) are both magnetized in the radial direction so that their respective magnetic poles are distributed on corresponding inner and outer rings, and the inner ring of the main outer magnetic ring (41) and the outer ring of the main inner magnetic ring (42) are arranged radially opposite to each other and have the same magnetic poles.

5. The hybrid magnetic levitation centrifugal blood pump according to claim 4, characterized in that: The outer magnetic ring group also includes a secondary outer magnetic ring (43) axially spliced ​​to one end of the main outer magnetic ring (41), the secondary outer magnetic ring (43) is axially magnetized, and the magnetic pole of the secondary outer magnetic ring (43) close to one end of the main inner magnetic ring (42) is the same as the magnetic pole of the outer ring of the main inner magnetic ring (42).

6. The hybrid magnetic levitation centrifugal blood pump according to claim 5, characterized in that: The inner magnetic ring group also includes a secondary inner magnetic ring (44) axially spliced ​​to one end of the main inner magnetic ring (42), the secondary inner magnetic ring (44) is magnetized radially, and the outer ring of the secondary inner magnetic ring (44) is radially opposite to the other end of the secondary outer magnetic ring (43) and has the same magnetic pole.

7. The hybrid magnetic levitation centrifugal blood pump according to claim 1, characterized in that: The impeller permanent magnetic suspension bearing (5) comprises an outer moving magnetic ring (51), an inner moving magnetic ring (52), an outer static magnetic ring (53) and an inner static magnetic ring (54); the outer moving magnetic ring (51) and the inner moving magnetic ring (52) are both built into the impeller lower cover (223), and the inner moving magnetic ring (52) is coaxially distributed in the middle of the outer moving magnetic ring (51); the outer static magnetic ring (53) and the inner static magnetic ring (54) are both built into the lower wall of the pump cavity (12), and the inner static magnetic ring (54) is coaxially distributed in the middle of the outer static magnetic ring (53); the outer moving magnetic ring (51) and the inner static magnetic ring (54), as well as the inner moving magnetic ring (52) and the outer static magnetic ring (53) repel each other, thereby generating a radial constraint and positioning effect on the impeller (22).

8. The hybrid magnetic levitation centrifugal blood pump according to claim 7, characterized in that: The outer moving magnetic ring (51), the inner moving magnetic ring (52), the outer static magnetic ring (53) and the inner static magnetic ring (54) are all magnetized along the axis. The outer moving magnetic ring (51) and the outer static magnetic ring (53) are axially arranged opposite to each other and have different magnetic poles at one end opposite to each other. The inner moving magnetic ring (52) and the inner static magnetic ring (54) are axially arranged opposite to each other and have different magnetic poles at one end opposite to each other. At the same time, the magnetic pole distributions of the upper and lower ends of the outer moving magnetic ring (51) and the inner moving magnetic ring (52) are opposite, and the magnetic pole distributions of the upper and lower ends of the outer static magnetic ring (53) and the inner static magnetic ring (54) are opposite.

9. The hybrid magnetic levitation centrifugal blood pump according to claim 7, characterized in that: The impeller permanent magnetic suspension bearing (5) further comprises a static magnetic core (55) built into the central cone (13); the static magnetic core (55) is coaxially distributed in the middle of the inner moving magnetic ring (52) and repel each other.

10. The hybrid magnetic levitation centrifugal blood pump according to claim 1, characterized in that: The iron core (631) is provided with a first core portion (6311) distributed along the radial direction of the rotor (21) and a second core portion (6312) extending vertically downward from an end of the first core portion (6311) facing away from the rotor (21); The electrically controlled magnetic core (61) is annular and magnetized in the radial direction. The other end of the first core portion (6311) is arranged opposite to the outer ring of the electrically controlled magnetic core (61). After the first core portion (6311) is magnetized by the energized coil (632), it can generate radial attraction or repulsion with the electrically controlled magnetic core (61). The electrically controlled magnetic ring (62) is magnetized in the axial direction, the lower end of the second core portion (6312) is arranged opposite to the electrically controlled magnetic ring (62), and the second core portion (6312) can generate an axial attraction force or an axial repulsion force with the electrically controlled magnetic ring (62) after being magnetized by the energized coil (632); The magnetic poles of the outer ring of the electrically controlled magnetic core (61) are different from the magnetic poles of the upper end of the electrically controlled magnetic ring (62).

11. The hybrid magnetic levitation centrifugal blood pump according to claim 1, characterized in that: The electromagnets (63) are N in number, and N is an even number greater than or equal to 4; two electromagnets (63) that are centrally symmetrical are combined into an electromagnet group, and the N electromagnets (63) are distributed into N / 2 electromagnet groups. Each electromagnet group can be controlled by an external controller to work independently, and two electromagnets (63) in the same electromagnet group work simultaneously.

12. The hybrid magnetic levitation centrifugal blood pump according to claim 11, characterized in that: Two coils (632), namely a first coil and a second coil, are wound around the iron core (631) of each electromagnet (63). The first coils of the two electromagnets (63) in the same electromagnet group are wound in opposite directions and are connected in series. When any one of the coils (632) of the electromagnet (63) is energized, the other coil (632) thereon is de-energized.

13. The hybrid magnetic levitation centrifugal blood pump according to claim 1, characterized in that: The electromagnetic suspension bearing (6) further comprises a circuit board (64) and a plurality of displacement sensors (65); the plurality of electromagnets (63) and the plurality of displacement sensors (65) are mounted on the circuit board (64) and are electrically connected to an external controller via the circuit board (64); The plurality of displacement sensors (65) are arranged one by one beside the plurality of electromagnets (63) and are arranged vertically opposite to the electrically controlled magnetic ring (62), and are used to cooperate with the electrically controlled magnetic ring (62) to detect the position signal of the impeller (22). An external controller controls the magnitude and direction of the current input to the corresponding electromagnet (63) according to the feedback of the position signal, so as to drive the rotor impeller (2) back to the center position.

14. The hybrid magnetic levitation centrifugal blood pump according to claim 1, characterized in that: The blood pump further comprises an auxiliary sliding bearing (7), wherein the auxiliary sliding bearing (7) comprises a sliding cone (71) and a sliding support surface (72), wherein the sliding cone (71) is fixedly arranged at the bottom of the rotor (21), and the sliding support surface (72) is fixedly arranged at the top of the central cone (13), and the sliding cone (71) is supported on the sliding support surface (72) by a ball head arranged at the lower end thereof; Wherein, the sliding cone (71) and the sliding support surface (72) are made of different bioceramic materials.

15. The hybrid magnetic levitation centrifugal blood pump according to claim 1, characterized in that: The pump head (11) comprises an inner tube (111) and an outer tube (112), wherein the outer tube (112) is sleeved on the outer side of the inner tube (111); The drive motor (3) comprises a stator winding (31) and a rotor magnetic steel (32), wherein the stator winding (31) is fixed between the inner tube (111) and the outer tube (112), and the rotor magnetic steel (32) is built into the rotor (21); The pump housing (1) is further provided with a pump upper shell (14), which is covered on a plurality of the electromagnets (63) and is sealedly connected to the inner tube (111), the outer tube (112) and the pump chamber (12).

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