Near-end supporting structure of blood pump and blood pump thereof

Abstract

The near-end supporting structure of the blood pump is high in abrasion resistance, good in lubricity and small in resistance, the near-end supporting structure of the blood pump comprises an impeller and a driving unit which are axially arranged and connected in a magnetic coupling mode, and the far end of a shell of the driving unit is provided with a connecting shaft in a protruding and extending mode in the direction of the impeller. The far end of the connecting shaft abuts against the near end of the impeller shaft to form axial limiting and circumferential running fit, the connecting shaft comprises a metal shaft, a blind hole is formed in a shaft core of the metal shaft, a ceramic column is inserted into the blind hole, and the far end surface of the ceramic column is smoothly connected with the far end surface of the metal shaft. The connecting shaft is arranged to be of a structure with the ceramic column in the middle and the metal shaft on the outer ring, the whole connecting shaft is still of a solid structure, and the overall strength meets the requirement. Wherein the ceramic material is high in hardness and abrasion resistance and can reduce abrasion, meanwhile, the metal material located on the outer ring has the good self-lubricating characteristic, rotation resistance is reduced, and rotation smoothness of the impeller is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of ventricular assist devices, and in particular to a proximal support structure of a blood pump and a blood pump thereof. Background Art

[0002] As a type of ventricular assist device, a blood pump can be percutaneously introduced into the heart and can be constructed to assist or replace the natural heart pump function through circulating or continuous pumping of blood, providing hemodynamic support for cardiogenic shock and acute heart failure. For a blood pump driven by magnetic coupling, in order to ensure the stability of the impeller movement, a supporting structure needs to be set at the proximal end of the impeller, but due to structural reasons, bearings cannot be used. In this case, in order to achieve the purpose of long-term operation of the motor, the motor shaft requires both high wear resistance and good lubricity and low resistance, which is also a difficult problem that needs to be solved urgently in the industry. Summary of the invention

[0003] One of the objects of the present invention is to provide a proximal support structure of a blood pump having high wear resistance, good lubricity and low resistance.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a proximal support structure of a blood pump, including an impeller and a drive unit which are axially arranged and connected by magnetic coupling. The distal end of the housing of the drive unit is provided with a connecting shaft protruding toward the impeller, and the distal end of the connecting shaft abuts against the proximal end of the impeller shaft to form axial limiting and circumferential rotation cooperation. The connecting shaft includes a metal shaft, a blind hole is opened at the core of the metal shaft, a ceramic column is inserted in the blind hole, and the distal surface of the ceramic column is smoothly connected with the distal surface of the metal shaft.

[0005] Furthermore, the distal surface of the connecting shaft is in a ball head / groove shape, and the proximal surface of the impeller shaft is in a groove / ball head shape that matches it. When the ball head abuts the groove, the bottom of the groove directly contacts and rubs with the top of the ball head, and the area outside the bottom of the groove contacts the surface of the area outside the top of the ball head.

[0006] Furthermore, the ceramic column is cylindrical, and the radius r1 of the ceramic column is 0.15 mm to 0.25 mm, and the radius r2 of the metal shaft is 0.4 mm to 0.6 mm.

[0007] Furthermore, the distal surface of the connecting shaft is in the shape of a hemispherical head, the depth of the groove is L, the radius of the hemispherical head is R1, L>R1, and the area outside the groove bottom contacts the distal surface and the distal outer peripheral surface of the metal shaft.

[0008] Furthermore, the radius of the groove matches the radius of the hemispherical head, and the radius r3 of the near section of the impeller shaft is 0.5 mm to 0.7 mm.

[0009] Furthermore, the metal shaft is made of stainless steel, and the proximal section of the impeller shaft is made of ceramic material or the inner surface of the proximal groove is coated with a ceramic coating.

[0010] Furthermore, the connecting shaft includes a support base integrally connected to the distal end of the shell, the support base includes a distal extension section protruding toward the distal end and a proximal extension section protruding toward the inner cavity of the shell, a slot is opened on the distal extension section, and the metal shaft is inserted into the slot to form a fixed connection.

[0011] Another object of the present invention is to provide a blood pump with high wear resistance, good lubricity and small size.

[0012] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a blood pump, wherein a plurality of magnetic columns are arranged in a shell, the magnetic columns and the magnets at the proximal end of the impeller are magnetically attracted to each other so that the connecting shaft abuts against the impeller shaft, a coil winding is wound around the magnetic columns, and the coil winding is controlled in turn to generate a rotating magnetic field, the magnet and the rotating magnetic field interact with each other to drive the rotation of the impeller, and the position where the connecting shaft abuts against the impeller shaft is located in the inner cavity of the magnet.

[0013] Furthermore, the impeller peripheral cover is provided with a blood cage, the proximal end of the blood cage is welded and fixed to the distal end of the shell, the blood cage is in the shape of a circular tube as a whole, the distal end of the circular tube constitutes a blood inlet, a plurality of blood outlets are opened on the proximal outer wall of the blood cage along its circumference, and a support frame for supporting the distal end of the impeller shaft is also provided at the circular tube mouth.

[0014] Furthermore, the inner cavity of the blood cage is provided with a variable diameter, including a distal small diameter section, a proximal large diameter section and a middle transition section, and the transition section corresponds to the position of a part of the middle section of the impeller.

[0015] In the above scheme, the connecting shaft is set to a structure with a ceramic column in the middle and a metal shaft on the outer ring. The entire connecting shaft is still a solid structure, and the overall strength meets the requirements. The ceramic material has high hardness and high wear resistance, which can reduce wear. At the same time, the metal material on the outer ring has good self-lubricating properties, which reduces the rotation resistance and ensures the smooth rotation of the impeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the structure of a blood pump; Figure 2 This is a schematic diagram of the internal structure of the blood cage; Figure 3 is a partial cross-sectional view of a blood pump; Figure 4 for Figure 3 The middle part is an enlarged schematic diagram; Figure 5 is a three-dimensional diagram of the shell; Figure 6 is a cross-sectional view of the connecting shaft; Figure 7 is a cross-sectional view of the shell; Figure 8 for Figure 7 Schematic diagram of the structure after removing the metal shaft and ceramic shaft. DETAILED DESCRIPTION

[0017] For the sake of convenience, we first define the directions involved in the following text: "proximal" and "proximal side" refer to the side close to the operator / doctor, and "distal" and "distal side" refer to the side away from the operator / doctor, that is, the side close to the heart. Figure 1-Figure 8 The invention is further described in detail.

[0018] A proximal support structure of a blood pump includes an impeller 10 and a drive unit 20 which are axially arranged and connected by magnetic coupling. A distal end of a housing 21 of the drive unit 20 is provided with a connecting shaft 22 which protrudes toward the impeller 10. The distal end of the connecting shaft 22 abuts against the proximal end of the impeller shaft 11 and forms an axial limit and circumferential rotation fit. The connecting shaft 22 includes a metal shaft 221. A blind hole is provided at the core of the metal shaft 221. A ceramic column 222 is inserted into the blind hole. The distal surface of the ceramic column 222 is smoothly connected with the distal surface of the metal shaft 221. The ceramic column 22 and the metal shaft 221 are fixedly connected by injecting adhesive.

[0019] The so-called magnetic coupling method refers to the mutual attraction between the magnetic column in the housing 21 of the drive 20 and the magnet 30 at the proximal end of the impeller 10, so that the impeller 10 always has a tendency to approach the drive unit 20. The drive unit 20 is also provided with a coil winding, which controls the coil winding to generate a rotating magnetic field in turn. The rotating magnetic field acts with the magnet 30 to drive the impeller 10 to rotate, and the distal end of the connecting shaft 22 abuts against the proximal end of the impeller shaft 11 and forms an axial limit and circumferential rotation match, thereby ensuring that the position of the impeller 10 is relatively stable while rotating. The stable rotation of the impeller 10 is crucial to the hydraulic performance and hemolytic performance of the blood pump. The position where the distal end of the connecting shaft 22 abuts against the impeller shaft 11 will wear under long-term rotational friction. If the wear is severe, on the one hand, it will cause the impeller 10 to be unstable when rotating, resulting in reduced hydraulic performance and failure to pump a sufficiently high blood flow, and will also increase damage to the blood; in addition, the abrasives produced by wear will enter the blood and flow to all parts of the patient's body with the blood circulation, causing certain safety hazards. Taking all factors into consideration, when the wear reaches a certain level, the blood pump can no longer be used, the service life of the blood pump is limited, and it cannot meet the needs of long-term support.

[0020] In the present invention, the connecting shaft 22 is configured to have a ceramic column 222 in the middle and a metal shaft 221 in the outer ring. The entire connecting shaft 22 is still a solid structure, and the overall strength meets the requirements. The ceramic material has high hardness and high wear resistance, which can reduce wear. At the same time, the metal material located in the outer ring has good self-lubricating properties, reduces the rotation resistance, and ensures the smooth rotation of the impeller 10.

[0021] As a preferred embodiment of the present invention, the distal surface of the connecting shaft 22 is in a ball head shape / groove shape, and the proximal surface of the impeller shaft 11 is in a groove shape / ball head shape that matches it. When the ball head abuts the groove, the groove bottom of the groove directly contacts and rubs with the top of the ball head, and the area outside the groove bottom contacts the surface of the area outside the top of the ball head. There are two schemes here. The first is that the shaft end of the connecting shaft 22 is in a ball head shape, and the shaft end of the impeller shaft 11 that matches it is in a groove shape; the second is that the shaft end of the connecting shaft 22 is in a groove shape, and the shaft end of the impeller shaft 11 that matches it is in a ball head shape. The top of the ball head and the bottom of the groove are the positions with the greatest friction and the most severe wear. Therefore, this position uses ceramic materials with high hardness and good wear resistance, while the peripheral position has relatively less friction and low wear. Therefore, stainless steel materials are used to maintain the self-lubrication of the shaft, reduce rotational resistance, and ensure the smooth rotation of the impeller 10. Here we prefer the first solution, because the blood flows from the distal side to the proximal side, that is, from one side of the impeller shaft 11 to the side of the connecting shaft 22. If the end face of the connecting shaft 2222 is grooved, the blood is easily retained in the groove, causing blood damage. In addition, the friction between the shafts will cause heat accumulation, so a guide hole (not shown in the figure) is usually required to guide the blood cooling. The ball-shaped design of the end of the connecting shaft 22 is conducive to the setting of the guide hole, which effectively prevents blood from being retained in the guide hole to form a flow dead zone and cause blood damage.

[0022] In order to take into account both wear resistance and self-lubrication, the area occupied by the ceramic part and the metal part on the friction surface is also crucial. After many tests, it was found that the ceramic column 222 is cylindrical, and the radius r1 of the ceramic column 222 is 0.15mm-0.25mm, and the radius r2 of the metal shaft 221 is 0.4mm-0.6mm. According to the surface area formula of the spherical crown, the surface area formula of the ceramic is: , The surface area formula of the metal shaft 221 shaft end is: , The ceramic surface and metal surface areas can be calculated from the formula and its radius range, and then the contact area between the outer periphery of the metal shaft 221 and the impeller shaft 111 can be added. This can meet both the wear resistance and the self-lubricating property of the shaft.

[0023] Furthermore, the distal surface of the connecting shaft 22 is in the shape of a hemispherical head, the depth of the groove 111 is L, the radius of the hemispherical head is R1, L>R1, and the area outside the groove bottom is in contact with the distal surface and the distal outer peripheral surface of the metal shaft 221. That is, the groove 111 exceeds the hemispherical head part to prevent the impeller shaft 11 from falling off the connecting shaft 22, enhance the stability of rotation, and reduce abnormal rotation noise. The radius of the hemispherical head R1 is equal to the radius r2 of the metal shaft 221, which is greater than 0.4mm~0.6mm, and the value of L is preferably 0.5mm~0.8mm, that is to say, the part of the groove 111 that exceeds the hemispherical head should not be too short or too long. If it is too short, the effect of limiting and preventing disengagement is not obvious, and if it is too long, it is not easy to assemble.

[0024] The radius of the groove 111 matches the radius of the hemispherical head, and the radius r3 of the proximal section of the impeller shaft 11 is 0.5 mm to 0.7 mm. The radius of the impeller shaft 11 is larger than the radius of the metal shaft 221, so that the groove shape of the shaft end of the impeller shaft 11 can be completely wrapped around the outer periphery of the metal shaft 221, so that the annular gap between the impeller shaft 11 and the peripheral magnet 30 is smaller than the annular gap between the metal shaft 221 and the peripheral magnet 30, which is conducive to the flow of flushing blood.

[0025] Furthermore, the metal shaft 221 is made of stainless steel, which has high hardness and strength, can withstand large loads and impacts, and has strong corrosion resistance and mechanical properties. The proximal section of the impeller shaft 11 is made of ceramic material or the inner surface of the proximal groove 111 is coated with a ceramic coating to further improve wear resistance.

[0026] In order to facilitate the processing and assembly of the metal shaft 221 and the ceramic column 222, it is preferred to set the connecting shaft 22 as a segmented structure, that is, the connecting shaft 22 includes a support seat 223 integrally connected to the distal end of the shell 21, and the support seat 223 includes a distal extension section 223a protruding toward the distal end and a proximal extension section 223b protruding toward the inner cavity of the shell 21. The distal extension section 223a is provided with a slot 223c, and the metal shaft 221 is inserted into the slot 223c and forms a fixed connection. The support seat 223 is integrally processed and formed with the shell 21, and the metal shaft 221 and the ceramic column 222 are separately processed and assembled, and then welded and fixed to the support seat 223. At the same time, the proximal extension section 223b of the support seat 223 protruding toward the inner cavity of the shell 21 further enhances the connection strength of the support seat 223 and ensures the reliability of the connecting shaft 22.

[0027] like Figure 1-Figure 3As shown, a blood pump is provided in a housing 21 with a plurality of magnetic columns (not shown in the figure). The magnetic columns and the magnets 30 at the proximal end of the impeller 10 are magnetically attracted to each other so that the connecting shaft 22 abuts against the impeller shaft 11. Coil windings (not shown in the figure) are wound around the magnetic columns, which in turn control the coil windings to generate a rotating magnetic field. The magnets 30 interact with the rotating magnetic field to drive the rotation of the impeller 10. The connecting shaft 22 abuts against the impeller shaft 11 at a position located in the inner cavity of the magnet 30. The magnetic columns and the magnets 30 at the proximal end of the impeller 10 attract each other so that the impeller 10 always has a tendency to approach the drive unit 20. The drive unit 20 is also provided with a coil winding, which in turn controls the coil windings to generate a rotating magnetic field. The rotating magnetic field interacts with the magnets 30 to drive the impeller 10 to rotate. A blood pump of this structure includes, but is not limited to, the following technical advantages: 1. The distal end of the housing 21 is a closed structure, and blood cannot enter the interior of the housing 21, so there will be no thrombosis, and there is no need to set up a backwashing system, which has no effect on the increase of blood pressure or the burden on the heart; 2. A non-contact magnetic coupling driving method is adopted, and a rotating magnetic field is generated by controlling the coil winding in the housing 21 to interact with the magnet 30 to drive the rotation of the impeller 10, thereby simplifying the structure of the driving device; 3. Small size can provide large torque, and due to its small size, it is less invasive; 4. No bearings, reduced wear, longer service life of the blood pump, suitable for long-term hemodynamic support.

[0028] Furthermore, the outer peripheral cover of the impeller 10 is provided with a blood cage 40, the proximal end of the blood cage 40 is welded and fixed to the distal end of the shell 21, the blood cage 40 is in the shape of a circular tube as a whole, the distal end of the circular tube constitutes a blood inlet, and a plurality of blood outlets 41 are opened on the proximal outer peripheral wall of the blood cage 40 along its circumference, and a support frame 42 for supporting the distal end of the impeller shaft 11 is also provided at the tube mouth of the circular tube. Both the proximal and distal ends of the impeller shaft 11 are supported and have good stability.

[0029] In order to guide the outflowing blood, the inner cavity of the blood cage 40 is provided with a variable diameter, including a distal small diameter section, a proximal large diameter section and a middle transition section, and the transition section corresponds to the position of the middle section of the impeller 10. In other words, the inner diameter of the blood cage 40 near the blood outlet 41 becomes larger, and the larger outlet diameter helps to reduce the shear force of the blood at the outlet; at the same time, it also helps to reduce the eddy and turbulent phenomena of the blood, making the blood flow more stable and uniform, and improving the efficiency of the pump.

[0030] The embodiments described above are only some embodiments of the present application, rather than all embodiments. The preferred embodiments of the present application are given in the accompanying drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application is described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to replace some of the technical features therein with equivalents. Any equivalent structure made using the contents of the specification and drawings of this application, directly or indirectly used in other related technical fields, is also within the scope of patent protection of this application.

Claims

1. A proximal support structure of a blood pump, comprising an impeller (10) and a drive unit (20) arranged axially and connected by magnetic coupling, wherein a distal end of a housing (21) of the drive unit (20) is provided with a connecting shaft (22) protruding toward the impeller (10), and the distal end of the connecting shaft (22) abuts against the proximal end of the impeller shaft (11) to form an axial limit and circumferential rotation fit, characterized in that: The connecting shaft (22) comprises a metal shaft (221), a blind hole is provided at the core of the metal shaft (221), a ceramic column (222) is inserted into the blind hole, and the distal surface of the ceramic column (222) is smoothly connected to the distal surface of the metal shaft (221).

2. The proximal support structure of a blood pump according to claim 1, characterized in that: The distal end surface of the connecting shaft (22) is in a ball head shape / groove shape, and the proximal end surface of the impeller shaft (11) is in a groove shape / ball head shape that matches the impeller shaft (11). When the ball head abuts against the groove, the bottom of the groove directly contacts and rubs against the top of the ball head, and the area outside the bottom of the groove contacts the surface of the area outside the top of the ball head.

3. The proximal support structure of a blood pump according to claim 1, characterized in that: The ceramic column (222) is cylindrical, and the radius r1 of the ceramic column (222) is 0.15 mm to 0.25 mm, and the radius r2 of the metal shaft (221) is 0.4 mm to 0.6 mm.

4. The proximal support structure of a blood pump according to claim 2, characterized in that: The distal surface of the connecting shaft (22) is in the shape of a hemispherical head, the depth of the groove (111) is L, the radius of the hemispherical head is R1, L>R1, and the area outside the groove bottom is in contact with the distal surface and the distal outer peripheral surface of the metal shaft (221).

5. The proximal support structure of a blood pump according to claim 4, characterized in that: The radius of the groove (111) coincides with the radius of the hemispherical head, and the radius r3 of the proximal section of the impeller shaft (11) is 0.5 mm to 0.7 mm.

6. The proximal support structure of a blood pump according to claim 1, characterized in that: The metal shaft (221) is made of stainless steel, and the proximal section of the impeller shaft (11) is made of ceramic material or the inner surface of the proximal groove (111) is coated with a ceramic coating.

7. The proximal support structure of a blood pump according to claim 1, characterized in that: The connecting shaft (22) comprises a support seat (223) integrally connected to the distal end of the shell (21); the support seat (223) comprises a distal extension section (223a) protruding toward the distal end and a proximal extension section (223b) protruding toward the inner cavity of the shell (21); a slot (223c) is provided on the distal extension section (223a); the metal shaft (221) is inserted into the slot (223c) to form a fixed connection.

8. A blood pump, comprising the proximal support structure of the blood pump according to any one of claims 1 to 7, characterized in that: A plurality of magnetic columns are arranged in the housing (21), and the magnetic columns and the magnets (30) at the proximal end of the impeller (10) are magnetically attracted to each other so that the connecting shaft (22) and the impeller shaft (11) are in contact with each other. Coil windings are wound around the magnetic columns, and the coil windings are sequentially controlled to generate a rotating magnetic field. The magnets (30) interact with the rotating magnetic field to drive the impeller (10) to rotate. The position where the connecting shaft (22) and the impeller shaft (11) are in contact with each other is located in the inner cavity of the magnet (30).

9. The blood pump according to claim 8, characterized in that: The impeller (10) is provided with a blood cage (40) on its outer peripheral cover. The proximal end of the blood cage (40) is welded and fixed to the distal end of the housing (21). The blood cage (40) is in the shape of a circular tube as a whole. The distal end of the circular tube forms a blood inlet. A plurality of blood outlets (41) are provided on the proximal outer peripheral wall of the blood cage (40) along its circumference. A support frame (42) for supporting the distal end of the impeller shaft (11) is also provided at the tube mouth of the circular tube.

10. The blood pump according to claim 9, characterized in that: The inner cavity of the blood cage (40) is provided with a variable diameter, comprising a distal small diameter section, a proximal large diameter section, and a middle transition section, wherein the transition section corresponds to the position of the middle section of the impeller (10).

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