Medical centrifugal blood pump head and centrifugal blood pump

Abstract

The invention provides a pump head of a medical centrifugal blood pump and the centrifugal blood pump. The pump head of the medical centrifugal blood pump comprises a pump shell; the impeller is arranged in the pump shell; the sliding friction pair is arranged in the pump shell and comprises a bearing and a bearing seat which are matched with each other, the bearing seat supports the impeller through the bearing, the material of the bearing comprises silicon nitride ceramic, and the material of the bearing seat comprises polyether-ether-ketone. According to the medical centrifugal blood pump head and the centrifugal blood pump, silicon nitride ceramic is adopted as the bearing, polyether-ether-ketone is adopted as the bearing seat, a friction pair combination capable of being applied to the centrifugal blood pump head is provided, and the service life of the centrifugal blood pump head can be prolonged on the premise that the function of the centrifugal blood pump head is not affected.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a medical centrifugal blood pump head and a centrifugal blood pump. Background Art

[0002] Centrifugal blood pumps are used to establish blood circulation channels outside the body to assist the heart in pumping blood during cardiac surgery or when the patient suffers from voluntary shock. Network percutaneous left ventricular assist device (PLVAD system), extracorporeal membrane oxygenation system (ECMO) and extracorporeal circulation system, etc., can all use centrifugal blood pumps as power devices to replace the heart's pumping blood. Centrifugal blood pumps are both key equipment to replace the heart's pumping function and an important device to maintain blood pumping throughout the body.

[0003] The medical centrifugal blood pump mainly includes a pump head, and the main structure of the pump head generally includes a pump casing, an impeller, a bearing and a bearing seat. When the impeller rotates, the blood rotates at high speed under the action of centrifugal force, obtains pressure energy inside the pump casing, and finally flows out from the outlet, thereby realizing the pumping of blood. The bearing seat, as the supporting component of the entire impeller, also bears the friction between the bearing and the bearing seat. The two parts of the bearing and the bearing seat are called a friction pair combination. Due to the special use scenario of the pump head of a medical centrifugal blood pump, the material of the friction pair combination must have both good biocompatibility (cannot affect the properties of the blood) and good wear resistance (friction loss and surface roughness are as low as possible).

[0004] Therefore, developing better friction pair combinations has always been a pressing issue in this field. Summary of the invention

[0005] The present application provides a medical centrifugal blood pump head and a centrifugal blood pump, which can increase the service life of the centrifugal blood pump head without affecting the function of the centrifugal blood pump head.

[0006] One aspect of the present application provides a medical centrifugal blood pump head, comprising: a pump casing; an impeller, the impeller being arranged inside the pump casing; a sliding friction pair, the sliding friction pair being arranged inside the pump casing, comprising a bearing and a bearing seat that are adapted to each other, the bearing seat supporting the impeller through the bearing, wherein the material of the bearing comprises silicon nitride ceramics, and the material of the bearing seat comprises polyetheretherketone.

[0007] In some embodiments of the present application, the first end of the bearing seat is assembled at the bottom center of the pump housing, and the second end surface of the bearing seat is provided with a friction surface adapted to the bearing.

[0008] In some embodiments of the present application, the friction surface is a hemispherical surface, the bearing is a sphere, a portion of the sphere is embedded in the back of the impeller, and another portion of the sphere protrudes from the back of the impeller and contacts the hemispherical surface.

[0009] In some embodiments of the present application, the bearing includes one or more of the following features: the diameter variation of the bearing does not exceed 0.25 microns, the spherical error does not exceed 0.25 microns, and the surface roughness does not exceed Ra0.014.

[0010] In some embodiments of the present application, the friction surface is an arc surface, the bearing is an arc column, the arc column includes a cylinder and an arc body located at one end of the cylinder, the cylinder is embedded in the back of the impeller, and the arc body protrudes from the back of the impeller and contacts the arc surface.

[0011] In some embodiments of the present application, the components of the silicon nitride ceramic include: silicon nitride, aluminum oxide, yttrium oxide and magnesium oxide.

[0012] In some embodiments of the present application, among the components of the silicon nitride ceramic, the mass proportion of silicon nitride is 83% to 97%; the mass proportion of aluminum oxide is 1% to 5%; the mass proportion of yttrium oxide is 1% to 10%; and the mass proportion of magnesium oxide is 1% to 2%.

[0013] In some embodiments of the present application, the bearing includes a main body and a coating, the coating covers the surface of the main body having a friction relationship with the bearing seat, the material of the main body includes a metal alloy coated with a ceramic material; the material of the coating includes silicon nitride ceramic.

[0014] In some embodiments of the present application, the thickness of the coating is 0.01 mm to 0.2 mm.

[0015] Another aspect of the present application also provides a centrifugal blood pump, including: a pump housing and a pump cover, the pump housing and the pump cover forming a sealed cavity; a drive motor, arranged in the sealed cavity; an external magnetic coupling support, arranged above the drive motor and connected to the drive motor; an external magnetic coupling, arranged on the external magnetic coupling support and fixedly connected to the external magnetic coupling support; the above-mentioned centrifugal blood pump head, arranged on the pump cover; a pump head fixing mechanism, fixing the centrifugal blood pump head to the pump cover.

[0016] The medical centrifugal blood pump head and centrifugal blood pump provided in the present application use silicon nitride ceramics as bearings and polyetheretherketone as bearing seats, providing a friction pair combination that can be applied to the centrifugal blood pump head, which can increase the service life of the centrifugal blood pump head without affecting the function of the centrifugal blood pump head. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following figures describe in detail the exemplary embodiments disclosed in this application. The same reference numerals represent similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting, exemplary embodiments, and the drawings are only for the purpose of illustration and description, and are not intended to limit the scope of this application. Other embodiments may also accomplish the inventive intent in this application. It should be understood that the drawings are not drawn to scale.

[0018] in:

[0019] Figure 1 It is a schematic cross-sectional view of the structure of a centrifugal blood pump head according to some embodiments of the present application;

[0020] Figure 2 It is a schematic cross-sectional view of the structure of a centrifugal blood pump head according to other embodiments of the present application;

[0021] Figure 3 This is a schematic cross-sectional view of the structure of a centrifugal blood pump described in some embodiments of the present application. DETAILED DESCRIPTION

[0022] The following description provides specific application scenarios and requirements of the present application, with the purpose of enabling those skilled in the art to make and use the content in the present application. It will be apparent to those skilled in the art that various local modifications to the disclosed embodiments are apparent, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the embodiments shown, but to the widest scope consistent with the claims.

[0023] The technical solution of the present invention is described in detail below in conjunction with the embodiments and drawings.

[0024] Figure 1 This is a schematic cross-sectional view of the structure of a centrifugal blood pump head according to some embodiments of the present application. Figure 2 It is a schematic cross-sectional view of the structure of a centrifugal blood pump head described in other embodiments of the present application.

[0025] The present application provides a medical centrifugal blood pump head, referring to Figure 1 and Figure 2 As shown, it includes: a pump casing 1; an impeller 2, wherein the impeller 2 is arranged inside the pump casing 1; a sliding friction pair, wherein the sliding friction pair is arranged inside the pump casing 1, and includes a bearing 3 and a bearing seat 4 that are adapted to each other, wherein the bearing seat 4 supports the impeller 2 through the bearing 3, wherein the material of the bearing 3 includes silicon nitride ceramics, and the material of the bearing seat 4 includes polyetheretherketone.

[0026] In some embodiments of the present application, the first end of the bearing seat 4 is assembled at the bottom center of the pump housing 1 , and the second end surface of the bearing seat 4 is provided with a friction surface adapted to the bearing 3 .

[0027] In some embodiments of the present application ( Figure 1 In the embodiment shown in the figure, the friction surface is a hemispherical surface, the bearing 3 is a sphere, a part of the sphere is embedded in the back of the impeller 2, and the other part of the sphere protrudes from the back of the impeller 2 and contacts the hemispherical surface.

[0028] In some embodiments of the present application, the bearing includes one or more of the following features: the diameter variation (ie, tolerance zone) of the bearing does not exceed 0.25um, the spherical error does not exceed 0.25um, and the surface roughness does not exceed Ra0.014.

[0029] In some embodiments of the present application ( Figure 2 In the embodiment shown in the figure, the friction surface is an arc surface, the bearing 3 is an arc surface column, the arc surface column includes a cylinder 31 and an arc body 32 located at one end of the cylinder 31, the cylinder 31 is embedded in the back of the impeller 2, and the arc body 32 protrudes from the back of the impeller 2 and contacts the arc surface.

[0030] In some embodiments of the present application, the silicon nitride ceramic may be entirely composed of silicon nitride material.

[0031] In some other embodiments of the present application, the components of the silicon nitride ceramic include: silicon nitride, aluminum oxide, yttrium oxide and magnesium oxide.

[0032] In some embodiments of the present application, among the components of the silicon nitride ceramic, the mass proportion of silicon nitride is 83% to 97%; the mass proportion of aluminum oxide is 1% to 5%; the mass proportion of yttrium oxide is 1% to 10%; the mass proportion of magnesium oxide is 1% to 2%. Silicon nitride has a strong hardness, and its preparation process often uses aluminum oxide, yttrium oxide, magnesium oxide, etc. as sintering aids to improve the sintering effect. Aluminum oxide and magnesium oxide can weaken the anisotropy of grain growth and promote grain refinement; yttrium oxide particles are uniform and have good fluidity, which promotes the growth of silicon nitride grains; silicon nitride powder particles are smaller than other additives, and can achieve a higher roughness level in later grinding.

[0033] In some embodiments of the present application, the bearing 3 includes a main body and a coating, the coating covers the surface of the main body having a friction relationship with the bearing seat, the material of the main body includes a metal alloy coated with a ceramic material; the material of the coating includes silicon nitride ceramic. In other words, the silicon nitride ceramic coating can only cover the surface of the main body having a friction relationship with the bearing seat, and the material constituting the bearing main body can be selected as needed, which not only satisfies the good wear resistance of the friction surface of the bearing and the bearing seat, but also makes the main body material of the bearing 3 more selective.

[0034] In some embodiments of the present application, the bearing 3 is a sphere, and the main body is a sphere, and the coating covers the entire surface of the main body.

[0035] In some other embodiments of the present application, the bearing 3 is a cambered column, and the main body is a cambered column, and the coating covers the arc-shaped surface of the cambered column.

[0036] In some embodiments of the present application, the thickness of the coating is 0.01 mm to 0.2 mm, which can meet the requirements of good wear resistance and biocompatibility.

[0037] When working, the impeller 2 rotates around the axis of the bearing seat 4 through the cooperation of the bearing 3 and the bearing seat 4, thereby driving the blood in the pump housing 1 to perform centrifugal motion, thereby realizing the blood pumping function of the centrifugal blood pump head. In the centrifugal blood pump head described in the embodiment of the present application, when the impeller 2 rotates, the bearing 3 is driven to slide on the friction surface of the bearing seat 4, and the bearing 3 and the bearing seat 4 constitute a sliding friction pair.

[0038] Due to the special use scenarios of medical centrifugal blood pump heads, the materials of the friction pair combination must have both good biocompatibility (not affecting the properties of the blood) and good wear resistance (friction loss and surface roughness are as low as possible). On the one hand, the friction between the bearing 3 and the bearing seat 4 has friction loss, which causes the bearing 3 and the bearing seat 4 to deform, which will reduce the service life of the centrifugal blood pump head. On the other hand, the friction between the bearing 3 and the bearing seat 4 will also crush the blood and damage blood cells. In addition, the bearing 3 and the bearing seat 4 are in direct contact with the blood and cannot contaminate the blood and affect the properties of the blood.

[0039] At present, the friction pair combination materials used in some centrifugal blood pump heads generally include aluminum oxide or zirconium oxide, etc. However, the biocompatibility and wear resistance of these materials are still insufficient, and biocompatibility and wear resistance are important factors affecting the performance of centrifugal blood pump heads. Table 1 shows the friction pair combination materials suitable for centrifugal blood pump heads and their performance comparisons. Referring to Table 1, it can be seen that the hardness, surface roughness and solution contact angle of the silicon nitride ceramic material used in the embodiment of the present application are better than aluminum oxide and zirconium oxide.

[0040] Table 1: Performance comparison of different friction pair combination materials

[0041] unit Silicon Nitride Alumina Zirconia ABS PEEK hardness Gpa 2.5 1.8-2.0 1.2-1.3 0.12 0.15 Elastic modulus Gpa 320 350 200 2 4 strength Mpa 1000 400-600 1000 50 100 Surface roughness / Ra0.014 Ra0.032 Ra0.032 Ra0.032 Ra0.032 solution contact angle ° 31-35 72 / / /

[0042] Based on this, the technical solution of the present application provides an excellent sliding friction pair combination, including a bearing 3 and a bearing seat 4 that are adapted to each other, wherein the material of the bearing 3 includes silicon nitride ceramics, and the material of the bearing seat 4 includes polyetheretherketone (PEEK).

[0043] Due to the special application scenario of the centrifugal blood pump head, it is necessary to ensure the biocompatibility of the bearing 3 and the bearing seat 4. The silicon nitride ceramic bearing and the polyetheretherketone bearing seat described in the embodiment of the present application can meet the following tests on biocompatibility.

[0044] In some embodiments of the present application, an in vitro cytotoxicity test is performed on the silicon nitride ceramic bearing and the polyetheretherketone bearing seat in accordance with the GB / T 16886.5-2017 standard. The experimental results of the silicon nitride ceramic bearing are that the cell survival rate is greater than 90%, and the experimental results of the polyetheretherketone bearing seat are that the cell survival rate is greater than 70%.

[0045] In some embodiments of the present application, the silicon nitride ceramic bearing and the polyetheretherketone bearing seat were subjected to stimulation and skin sensitization tests in accordance with GB / T 16886.10-2017 standard, and the test results showed that no intradermal irritation reaction and sensitization reaction were found on the skin of the test animals with the silicon nitride ceramic bearing and the polyetheretherketone bearing seat.

[0046] In some embodiments of the present application, the silicon nitride ceramic bearings and polyetheretherketone bearing seats were subjected to acute systemic toxicity reaction tests in accordance with GB / T 16886.11-2021 standard, and the test results showed that no abnormal reactions or deaths were observed in all test animals.

[0047] In some embodiments of the present application, the silicon nitride ceramic bearing and the polyetheretherketone bearing seat are tested for interaction with blood in accordance with GB / T 16886.4-2003 standard. The experimental result of the silicon nitride ceramic bearing is that the hemolysis rate is 0, and the experimental result of the polyetheretherketone bearing seat is that the hemolysis rate is less than 5%.

[0048] In some embodiments of the present application, the silicon nitride ceramic bearings and the polyetheretherketone bearing seats are subjected to pyrogenic reaction tests in accordance with the pyrogenic test method of Part 4 of the 2020 edition of the Chinese Pharmacopoeia. The test results show that the silicon nitride ceramic bearings and the polyetheretherketone bearing seats have no pyrogenic reaction.

[0049] In summary, the centrifugal blood pump head described in the embodiment of the present application adopts a silicon nitride ceramic bearing and a polyetheretherketone bearing seat to cooperate with each other to form a sliding friction pair combination, which not only has good biocompatibility and can ensure that there is no impact on the blood; at the same time, the sliding friction pair combination composed of the silicon nitride ceramic bearing and the polyetheretherketone bearing seat also has good wear resistance, which can increase the service life of the centrifugal blood pump head; in addition, the sliding friction pair combination composed of the silicon nitride ceramic bearing and the polyetheretherketone bearing seat is more stable and has no abnormal noise compared to the silicon nitride ceramic bearing and bearing seat, and is more suitable for use in medical blood pumps.

[0050] In order to further understand the performance of the sliding friction pair combination composed of the silicon nitride ceramic bearing and the polyetheretherketone bearing seat described in the embodiment of the present application, the embodiments of the present application and several comparative examples are designed below, and experiments are carried out on the embodiments and comparative examples.

[0051] In the following embodiments and comparative examples, different materials are used to make bearings and matching bearing seats, wherein the bearings are spheres.

[0052] Table 2: Friction pair materials of the embodiments and different comparative examples

[0053]

[0054] As shown in Reference Table 2, in Example 1, the material of the bearing is silicon nitride ceramic, wherein the silicon nitride ceramic includes 90wt% silicon nitride, 4wt% aluminum oxide, 5wt% yttrium oxide and 1wt% magnesium oxide; the material of the bearing seat is polyetheretherketone (PEEK). In Comparative Example 1, the material of the bearing is zirconium oxide (ZrO2), and the material of the bearing seat is PEEK. In Comparative Example 2, the material of the bearing is aluminum oxide (Al2O3), and the material of the bearing seat is PEEK. In Comparative Example 3, the material of the bearing is silicon nitride ceramic, wherein 90wt% silicon nitride, 4wt% aluminum oxide, 5wt% yttrium oxide and 1wt% magnesium oxide; the material of the bearing seat is acrylonitrile-butadiene-styrene plastic (ABS).

[0055] A friction loss test was conducted on the above-mentioned embodiments and comparative examples. Under the lubrication and equivalent pressure of simulated blood, the wear was carried out for 6 hours, and the change in the surface profile of the bearing seat before and after the test was recorded. The greater the change in the surface profile, the greater the wear.

[0056] Table 3: Wear test results

[0057] Example Changes in bearing seat surface profile Example 1 0.005 mm Comparative Example 1 0.014 mm Comparative Example 2 0.008 mm Comparative Example 3 0.015 mm

[0058] With reference to Table 3, it can be known that the wear of the friction pair combination of the silicon nitride ceramic bearing and the polyetheretherketone bearing seat described in the embodiment of the present application is the lowest.

[0059] The bearings and bearing seats in the above embodiments and comparative examples are subjected to biocompatibility tests (including cytotoxicity, sensitization reaction, intradermal irritation, acute toxicity, material-induced hemolysis and pyrogenic reaction). Among them, the cytotoxicity test is to conduct an in vitro cytotoxicity test (MTT method) on the bearings and bearing seats in accordance with GB / T16886.5-2017, detect the potential cytotoxicity of the bearings and bearing seats, and record the cell survival rate of the bearing and bearing seat extract test results (the standard requires not less than 70%). The higher the cell survival rate, the better. The sensitization reaction and intradermal irritation test are to conduct stimulation and skin sensitization tests on the bearings and bearing seats in accordance with GB / T 16886.10-2017, evaluate the potential intradermal irritation reaction and skin sensitization reaction of the bearings and bearing seats, and record whether there are intradermal irritation reactions and skin sensitization reactions. The acute toxicity test is to conduct an acute systemic toxicity reaction test on the bearings and bearing seats in accordance with GB / T 16886.11-2021, evaluate the potential acute systemic toxicity reaction of the bearings and bearing seats, and record whether there are abnormal reactions or deaths in the test animals. The material-induced hemolysis test is to conduct a blood interaction test on the bearings and bearing seats in accordance with GB / T 16886.4-2003, evaluate the potential hemolytic reaction of the bearings and bearing seats, and record the hemolysis rate (the standard requires no more than 5%). The lower the hemolysis rate, the better. The pyrogenic reaction test is to conduct a pyrogenic reaction test on the bearings and bearing seats in accordance with the pyrogenic test method of Part 4 of the 2020 edition of the Chinese Pharmacopoeia, evaluate the potential pyrogenic reaction of the bearings and bearing seats, and record whether there is a pyrogenic reaction.

[0060] Table 4: Biocompatibility test results

[0061]

[0062] With reference to Table 4, it can be seen that the friction pair combination of the silicon nitride ceramic bearing and the PEEK bearing seat used in the embodiment of the present application has good biocompatibility and low biological risk.

[0063] The technical solution of the present application adopts a silicon nitride ceramic bearing and a polyetheretherketone bearing seat as a friction pair combination in a centrifugal blood pump head, which can obtain minimal wear and tear, thereby increasing the service life of the centrifugal pump head.

[0064] The technical solution of the present application adopts silicon nitride ceramic bearings and polyetheretherketone bearing seats as the friction pair combination in the pump head of a centrifugal blood pump. Judging from the test results of biocompatibility such as cytotoxicity, sensitization reaction, intracutaneous irritation, acute systemic toxicity, material-induced hemolysis, and pyrogenic reaction, it is a material combination with excellent biocompatibility.

[0065] The present application provides a medical centrifugal blood pump head, which uses silicon nitride ceramics as bearings and polyetheretherketone as a bearing seat, and provides a friction pair combination that can be applied to a centrifugal blood pump head, which can increase the service life of the centrifugal blood pump head without affecting the function of the centrifugal blood pump head.

[0066] Figure 3 This is a schematic cross-sectional view of the structure of a centrifugal blood pump described in some embodiments of the present application.

[0067] The embodiment of the present application also provides a centrifugal blood pump, referring to Figure 3 As shown, it includes: a pump housing 60 and a pump cover 30, the pump housing 60 and the pump cover 30 constitute a sealed cavity; a drive motor 50, which is arranged in the sealed cavity; an external magnetic coupling support 40, which is arranged above the drive motor 50 and connected to the drive motor 50; an external magnetic coupling 70, which is arranged on the external magnetic coupling support 40 and fixedly connected to the external magnetic coupling support 40; a centrifugal blood pump head 10 as described above, which is arranged on the pump cover 30, and the centrifugal blood pump head 10 also includes an internal magnetic coupling 80; a pump head fixing mechanism 20, which fixes the centrifugal blood pump head 10 to the pump cover 30. It should be noted that the detailed structure of the centrifugal blood pump head 10 has been described above and will not be repeated here.

[0068] When the driving motor 50 rotates, it drives the external magnetic coupling support 40 and the external magnetic coupling 70 to rotate. Due to the magnetic field force, the internal magnetic coupling 80 drives the entire centrifugal blood pump head 10 to passively rotate, thereby realizing the blood pumping function of the centrifugal blood pump head.

[0069] The present application provides a medical centrifugal blood pump head and a centrifugal blood pump, which use silicon nitride ceramics as bearings and polyetheretherketone as bearing seats, and provide a friction pair combination that can be applied to a centrifugal blood pump head, which can increase the service life of the centrifugal blood pump head without affecting the function of the centrifugal blood pump head.

[0070] In summary, after reading the contents of this application, those skilled in the art will appreciate that the aforementioned application contents may be presented only in an exemplary manner and may not be restrictive. Although not explicitly stated herein, those skilled in the art will appreciate that this application is intended to encompass various reasonable changes, improvements and modifications to the embodiments. These changes, improvements and modifications are within the spirit and scope of the exemplary embodiments of this application.

[0071] It should be understood that the term "and / or" used in this embodiment includes any or all combinations of one or more of the associated listed items. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to another element, or there can also be intermediate elements.

[0072] It should also be understood that the terms "comprising", "containing", "including" or "comprising", when used in this application document, indicate the presence of the recorded features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof.

[0073] In addition, the present specification describes exemplary embodiments by reference to idealized exemplary cross-sectional views and / or plan views and / or stereograms. Therefore, differences from the illustrated shapes due to, for example, manufacturing techniques and / or tolerances are foreseeable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but should include deviations in shapes caused by, for example, manufacturing. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the actual shapes of the regions of the device nor to limit the scope of the exemplary embodiments.

Claims

1. A medical centrifugal blood pump head, characterized in that: include: Pump housing; An impeller, wherein the impeller is disposed inside the pump casing; A sliding friction pair is arranged inside the pump housing, and includes a bearing and a bearing seat that fit each other, and the bearing seat supports the impeller through the bearing, wherein the material of the bearing includes silicon nitride ceramics, and the material of the bearing seat includes polyetheretherketone.

2. The centrifugal blood pump head according to claim 1, characterized in that: The first end of the bearing seat is assembled at the center of the bottom of the pump housing, and the second end surface of the bearing seat is provided with a friction surface adapted to the bearing.

3. The centrifugal blood pump head according to claim 2, characterized in that: The friction surface is a hemispherical surface, the bearing is a sphere, a part of the sphere is embedded in the back of the impeller, and the other part of the sphere protrudes from the back of the impeller and contacts the hemispherical surface.

4. The centrifugal blood pump head according to claim 3, characterized in that: The bearing includes one or more of the following features: the diameter variation of the bearing does not exceed 0.25um, the spherical error does not exceed 0.25um, and the surface roughness does not exceed Ra0.

014.

5. The centrifugal blood pump head according to claim 2, characterized in that: The friction surface is an arc surface, the bearing is an arc column, the arc column includes a cylinder and an arc body located at one end of the cylinder, the cylinder is embedded in the back of the impeller, and the arc body protrudes from the back of the impeller and contacts the arc surface.

6. The centrifugal blood pump head according to claim 1, characterized in that: The components of the silicon nitride ceramic include silicon nitride, aluminum oxide, yttrium oxide and magnesium oxide.

7. The centrifugal blood pump head according to claim 6, characterized in that: Among the components of the silicon nitride ceramic, silicon nitride accounts for 83% to 97% by mass; aluminum oxide accounts for 1% to 5% by mass; yttrium oxide accounts for 1% to 10% by mass; and magnesium oxide accounts for 1% to 2% by mass.

8. The centrifugal blood pump head according to claim 1, characterized in that: The bearing comprises a main body and a coating, wherein the coating covers a surface of the main body which has a friction relationship with the bearing seat, and the material of the main body comprises a metal alloy coated with a ceramic material; the material of the coating comprises silicon nitride ceramic.

9. The centrifugal blood pump head according to claim 8, characterized in that: The coating has a thickness of 0.01 mm to 0.2 mm.

10. A medical centrifugal blood pump, characterized in that: include: A pump casing and a pump cover, wherein the pump casing and the pump cover form a sealed cavity; A driving motor is arranged in the sealed cavity; An external magnetic coupling support is arranged above the driving motor and connected to the driving motor; An external magnetic coupling is arranged on the external magnetic coupling support and is fixedly connected to the external magnetic coupling support; The centrifugal blood pump head according to any one of claims 1 to 9, arranged on the upper cover of the pump machine; The pump head fixing mechanism fixes the centrifugal blood pump head on the pump machine upper cover.

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