Rotor assembly, motor and ventricular auxiliary blood pumping device

Abstract

The utility model discloses a rotor assembly, a motor and a ventricular auxiliary blood pumping device. The rotor assembly comprises a permanent magnet which comprises a body, a first cavity enclosed by the body, and a protective layer covering the outer surface, back to the first cavity, of the body; a part of the rotating shaft extends into the first cavity, a gap cavity is formed between the part of the rotating shaft and the permanent magnet, and the two ends, opposite in the axial direction, of the rotating shaft extend out of the permanent magnet; and the sealing connector blocks the gap cavity along two opposite ends of the axial direction of the gap cavity, and the sealing connector is respectively connected with the protective layers at the two ends in a sealing manner, so that the surface of the body is isolated from the external environment. The rotor assembly blocks the two axially opposite ends of the gap cavity through the sealing connectors and is in sealing connection with the protection layers at the two ends, the surface of the body is isolated from the external environment, and the permanent magnets are effectively protected against corrosion. And meanwhile, the inner surface of the body has high processing precision and can be assembled with a rotating shaft to obtain a high-precision rotor assembly, so that the yield of the motor is improved.

Description

Technical Field

[0001] The present application belongs to the field of electromechanical technology, and in particular relates to a rotor assembly, a motor, and a ventricular assist pumping device. Background Art

[0002] Sintered NdFeB is the third generation of rare earth permanent magnet material, known as the "King of Magnets". It is the most powerful permanent magnet material in the world and has excellent magnetic properties. The main components of the magnet are Nd2Fe 14 B has extremely high magnetic properties, with its maximum magnetic energy product (BH) exceeding that of ferrite by more than 10 times. In the pumping motors of ventricular assist devices, the permanent magnets in the rotor assembly are mostly made of sintered NdFeB.

[0003] Sintered NdFeB has a very high hardness, reaching 600-1000 Hv, making it difficult to machine. Due to NdFeB's inherently poor corrosion resistance, the entire surface of the permanent magnets made from magnetic steel typically requires various corrosion protection coatings, such as electroplating with Zn, Ni, Cu, Al, or epoxy coatings, depending on the specific corrosion protection requirements. These coatings can then be assembled with the shaft to form a rotor assembly. However, applying corrosion-resistant coatings to the magnetic steel surface results in large dimensional and positional tolerances. For example, the tolerances for inner diameter, outer diameter, length, and concentricity of existing annular permanent magnets made from magnetic steel are generally 0.05 mm or greater. This tolerance range results in a high failure rate in the assembly of blood pumping motors containing the permanent magnets. Therefore, there is an urgent need to address the problems of poor machining performance of permanent magnets made from magnetic steel, the large inner diameter tolerances caused by the application of an anti-corrosion coating on the inner surface, and the high failure rate of blood pumping motors assembled with the permanent magnets and the shaft. Furthermore, the permanent magnets must meet corrosion protection requirements. Utility Model Content

[0004] An embodiment of the present application provides a rotor assembly that can maintain good corrosion protection for the permanent magnets while maintaining a high level of machining accuracy for the inner surface of the body when assembled with the rotating shaft, thereby preventing a large inner diameter tolerance range caused by setting a protective layer on the inner surface of the permanent magnet in the first cavity and improving the yield of the assembled motor.

[0005] In the first aspect, the present application provides a rotor assembly, comprising: a permanent magnet, comprising a body, a first cavity formed by the body, and a protective layer covering the outer surface of the body facing away from the first cavity; a rotating shaft, a portion of the rotating shaft extending into the first cavity, a gap cavity formed between the portion of the rotating shaft and the permanent magnet, and the rotating shaft extending out of the permanent magnet at two axially opposite ends respectively; a sealing connector, blocking the gap cavity at least at two axially opposite ends of the gap cavity, and the sealing connector is sealed and connected to the protective layers at both ends respectively to isolate the surface of the body from the external environment.

[0006] In an embodiment of the first aspect of the present application, the sealing connector blocks the gap cavity at the outer sides at opposite axial ends of the gap cavity.

[0007] In an embodiment of the first aspect of the present application, a first transition fillet is provided on the outside of the sealing connector, the first transition fillet is concave toward between the permanent magnet and the rotating shaft, and the radius of the first transition fillet R is 0.3t~2t, where t is the radial wall thickness of the body.

[0008] In an embodiment of the first aspect of the present application, the interiors of the two opposite ends of the sealing connection body in the axial direction at least partially block the gap cavity.

[0009] In an embodiment of the first aspect of the present application, the portions of the sealing connection body respectively filling the interior of the gap cavity at two opposite ends along the axial direction each occupy 1 / 5 to 1 / 2 of the length of the gap cavity.

[0010] In an embodiment of the first aspect of the present application, the sealing connection body fills the entire gap cavity.

[0011] In an embodiment of the first aspect of the present application, a recess is provided at least on one of the two opposite ends of the permanent magnet in the axial direction. The recess is concave from the end surface of the permanent magnet toward the permanent magnet, and the sealing connector covers the recess.

[0012] In an embodiment of the first aspect of the present application, the recess protrudes toward the sealing connector to form a second transition fillet, and the radius of the second transition fillet R1 is 0.1t to 0.75t, where t is the radial wall thickness of the body.

[0013] In an embodiment of the first aspect of the present application, a protective layer is provided in a partial area of ​​the end surface of the body, and the sealing connector is sealed along the boundary of the end surface and the protective layer.

[0014] In an embodiment of the first aspect of the present application, the sealing connection body is in contact with the protective layer along the end surface of the main body.

[0015] In an embodiment of the first aspect of the present application, the sealing connection body covers the protective layer of the end surface of the body for sealing connection.

[0016] In an embodiment of the first aspect of the present application, the sealing connecting body is respectively filled in the interior of the two opposite ends of the gap cavity along the axial direction, and extends to the outside of the two opposite ends of the gap cavity along the axial direction, and is respectively sealed and connected to the protective layers at the two ends.

[0017] In an embodiment of the first aspect of the present application, the sealing connection body fills the entire gap cavity and extends to the outside of the two opposite ends of the gap cavity along the axial direction and is sealed and connected to the protective layer respectively.

[0018] In an embodiment of the first aspect of the present application, the outer diameter of the permanent magnet is 0.8 mm to 6.0 mm.

[0019] In an embodiment of the first aspect of the present application, the outer diameter tolerance of the permanent magnet is ≤0.03 mm.

[0020] In an embodiment of the first aspect of the present application, the inner diameter of the first cavity enclosed by the permanent magnet body is 0.3 mm to 2.0 mm.

[0021] In an embodiment of the first aspect of the present application, the inner diameter tolerance of the first cavity formed by the permanent magnet and the body is ≤0.02 mm.

[0022] In an embodiment of the first aspect of the present application, the concentricity of the first cavity formed by the permanent magnet and the body is ≤0.015 mm.

[0023] In an embodiment of the first aspect of the present application, the length of the permanent magnet is 3 mm to 30 mm.

[0024] In an embodiment of the first aspect of the present application, a length tolerance of the permanent magnet is ≤0.04 mm.

[0025] In an embodiment of the first aspect of the present application, the protective layer includes one or a composite layer of more than one of a surface passivation layer, a zinc-plated layer, a nickel-plated layer, a copper-plated layer, an epoxy-plated layer, a vacuum aluminum-plated layer, a sprayed zinc-aluminum layer, and a parylene coating.

[0026] In an embodiment of the first aspect of the present application, the thickness of the protective layer is 0.003 mm to 0.300 mm.

[0027] In an embodiment of the first aspect of the present application, the outer diameter tolerance of the rotating shaft is ≤0.005 mm.

[0028] In an embodiment of the first aspect of the present application, the rotating shaft is cylindrical.

[0029] In an embodiment of the first aspect of the present application, the cross-sectional shape of the rotating shaft perpendicular to its long axis is an N-gon, where N is a positive integer and N is greater than or equal to 6.

[0030] In an embodiment of the first aspect of the present application, the sealed connection is formed by an adhesive.

[0031] In a second aspect, the present application provides a motor, comprising: a stator assembly and the above-mentioned rotor assembly, wherein the above-mentioned rotor assembly is rotatably mounted in the stator assembly.

[0032] In an embodiment of the second aspect of the present application, the stator assembly includes: a winding, which encloses a second cavity; the winding and the permanent magnet are coaxially arranged on the outside of the permanent magnet with a preset gap; an iron core, which encloses a third cavity, and at least part of the winding is arranged in the third cavity; a proximal bearing, which is sleeved on the proximal end of the rotating shaft and is located at the first end of the winding; a distal shaft seat, including a mounting cavity, the distal shaft seat is arranged on the side of the second end of the winding opposite to the first end along its own length direction, and is connected to the iron core; the distal bearing is sleeved on the distal end of the rotating shaft opposite to the proximal end, and is located in the mounting cavity.

[0033] In an embodiment of the second aspect of the present application, the rotating shaft is connected to the proximal bearing and the distal bearing in sequence from the proximal end to the distal end.

[0034] In an embodiment of the second aspect of the present application, the motor further includes a casing, which encloses the proximal bearing and the iron core, and the distal shaft seat is connected to an end of the casing away from the proximal bearing.

[0035] On the third aspect, an embodiment of the present application provides a ventricular assist pumping device, comprising the above-mentioned motor, and an impeller connected to the distal end of the rotating shaft; and a catheter connected to the motor to form a circulation channel, the catheter being provided with a liquid inlet and a liquid outlet connected to the circulation channel, and the impeller being located in the circulation channel.

[0036] In the rotor assembly of the embodiment of the present application, the permanent magnet is sealed at both axially opposite ends of the gap cavity by a protective layer covering the outer surface of the body facing away from the first cavity, and the sealing connector is sealed to the protective layers at both ends, so that the surface of the body is isolated from the external environment, effectively protecting the permanent magnet from corrosion, and making it unnecessary to set a protective layer on the inner surface of the first cavity for the permanent magnet, so that the inner surface of the body can maintain a high processing accuracy, preventing the setting of the protective layer on the inner surface of the first cavity from causing a large inner diameter tolerance of the permanent magnet in the first cavity, so that the permanent magnet can be assembled with the rotating shaft extending into the first cavity with a smaller inner diameter tolerance to obtain a high-precision precision rotor assembly, thereby improving the yield of the motor assembled with the permanent magnet and the rotating shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 1 is a structural diagram of a permanent magnet provided in one embodiment of the present application.

[0039] Figure 2 This is a side view of one axial end of a permanent magnet provided in one embodiment of the present application.

[0040] Figure 3 yes Figure 1 Cross-sectional view of the permanent magnet along section line AA.

[0041] Figure 4 It is a schematic structural diagram of the rotor assembly provided in an embodiment of the present application.

[0042] Figure 5 yes Figure 4 Schematic diagram of the cross-sectional structure of the middle rotor assembly along section line AA.

[0043] Figure 6 It is a schematic cross-sectional structural diagram of the rotor assembly provided in an embodiment of the present application along the section line AA.

[0044] Figure 7 It is a schematic cross-sectional structural diagram of the rotor assembly provided in an embodiment of the present application along the section line AA.

[0045] Figure 8 It is a schematic cross-sectional structural diagram of the rotor assembly provided in an embodiment of the present application along the section line AA.

[0046] Figure 9 FIG. 1 is a schematic cross-sectional structural diagram of a rotor assembly provided by another embodiment along section line AA.

[0047] Figure 10 FIG. 1 is a schematic cross-sectional structural diagram of a rotor assembly provided by another embodiment along section line AA.

[0048] Figure 11 FIG. 1 is a schematic cross-sectional structural diagram of the ventricular assist pumping device according to the embodiment along the cross-sectional line AA.

[0049] Explanation of Reference Numerals: 1. permanent magnet; 100. first cavity; 101. protective layer; 102. recess; 103. end surface; 104. gap cavity; 105. body; 106. connecting portion; 2. rotating shaft; 200. distal end; 201. proximal end; 3. impeller; 4. winding; 400. second cavity; 401. preset gap; 402. first end; 403. second end; 5. iron core; 500, third cavity; 6, proximal bearing; 7, distal shaft seat; 700, mounting cavity; 8, distal bearing; 9, housing; 10, conduit; 10a, liquid inlet; 10b, liquid outlet; 11, circulation channel; 12, sealing connector; d1, inner diameter of the first cavity of the permanent magnet; d2, outer diameter of the permanent magnet; d3, outer diameter of the rotating shaft; L, axial direction; R, first transition fillet; R1, second transition fillet. DETAILED DESCRIPTION

[0050] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present application by illustrating the examples of the present application.

[0051] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, the elements defined by the phrase "comprising..." do not exclude the presence of other identical elements in the process, method, article, or device comprising the elements.

[0052] As described in the background technology section, the corrosion-resistant coating formed on the surface of permanent magnets made of magnetic steel results in large dimensional and geometric tolerances. This not only leads to a high rate of assembly failures in the pumping motor containing the magnetic steel, but also makes it difficult to meet the demand for smaller pumping motors for ventricular assist devices. Furthermore, due to the wide tolerance range of the permanent magnets, the pumping motor's characteristics fluctuate widely, and the motor's dynamic unbalance is difficult to control, leading to high vibration and noise levels in the motor.

[0053] In order to solve the problems existing in the prior art, embodiments of the present application provide a rotor assembly, a motor, and a ventricular assist pumping device.

[0054] The following first introduces the rotor assembly provided in the embodiment of the present application.

[0055] First, as Figure 4 As shown, the rotor assembly of the embodiment of the present application includes: a permanent magnet 1, such as Figures 1 to 3 As shown, the permanent magnet 1 includes a body 105, a first cavity 100 enclosed by the body 105, and a protective layer 101 covering the outer surface of the body 105 facing away from the first cavity 100; Figure 4As shown, the shaft 2, a portion of the shaft 2 extends into the first cavity 100, a gap cavity 104 is formed between the portion of the shaft 2 and the permanent magnet 1, and the two opposite ends of the shaft 2 along the axial direction L are respectively extended out of the permanent magnet 1; and a sealing connector 12, at least along the two opposite ends of the gap cavity 104 axial direction L to block the gap cavity 104, and the sealing connector 12 is respectively sealed with the protective layer 101 at the opposite ends to isolate the surface of the main body 105 from the external environment. Among them, the sealed connection can be that the sealing connector 12 is tightly connected to the protective layer 101, and at the same time, because the sealing connector 12 blocks the gap cavity 104, the main body 105 can be prevented from being exposed to the external environment from the boundary of the protective layer 101. The sealed connection includes the sealing connector being connected to the boundary of the protective layer, and the sealing connector covering the boundary of the protective layer, which is not specifically limited in this application.

[0056] In the rotor assembly of the embodiment of the present application, the permanent magnet is sealed at both axially opposite ends of the gap cavity by a protective layer covering the outer surface of the main body facing away from the first cavity, and the sealing connector is respectively sealed and connected to the protective layers at both ends, so that the surface of the main body is isolated from the external environment, effectively protecting the permanent magnet and preventing the permanent magnet from being corroded, so that the permanent magnet no longer needs to be provided with a protective layer on the inner surface of the first cavity, so that the inner surface of the main body can maintain a high processing accuracy, and the provision of a protective layer in the first cavity avoids the resultant large inner diameter tolerance of the permanent magnet first cavity, so that the permanent magnet can be assembled with a smaller inner diameter tolerance with the rotating shaft extending into the first cavity, thereby obtaining a high-precision rotor assembly, thereby improving the yield of the motor composed of the permanent magnet and the rotating shaft, and thus meeting the demand for a more miniaturized blood pumping motor for a ventricular assist blood pumping device.

[0057] In some embodiments of the present application, Figure 1 and 2 As shown, the connection between the first cavity 100 and the end face 103 of the main body 105 of the permanent magnet 1 and the connection between the outer diameter surface of the main body 105 of the permanent magnet 1 and the end face 103 are chamfered or rounded by 0.05mm to 0.3mm to form a connecting portion 106. The surface of the connecting portion 106 is also provided with a protective layer 101. Figure 1 and Figure 2 Not shown in the figure.

[0058] It should be noted that, in order to make the structure of the permanent magnet clear, Figure 1 The figure shows the end face 103 of the main body 105 of the permanent magnet 1 along the axial direction L. In the actual product of the permanent magnet 1, the end face 103 of at least one of the two opposite ends of the main body 105 along the axial direction forms a ring-shaped protective layer 101 around a part of the center of the end face or the entire end face. It is understandable that the protective layer 101 can also form multiple sector-shaped areas around the center of the end face, and the sector-shaped areas form protective layers of different shapes, such as semi-annular or annular, to partially or completely cover the end face. For example, Figure 1 and Figure 2 As shown, on the end surface 103 at one or both of the opposite ends of the body 105 in the axial direction L, the protective layer 101 can cover the connection portion 106 and be disposed in an annular shape around the center of the end surface 103. The coating width w of the protective layer 101 on the end surface 103 along the radial direction of the end surface 103 of the body 105 satisfies the following condition: w ≤ (d2 - d1) / 2. Therefore, a protective layer can be formed in an annular shape around a portion of the end surface or the entire end surface around the center of the end surface.

[0059] In some embodiments of the present application, the protective layer 101 covers the outer peripheral surface of the body 105 away from the first cavity 100, or, as Figure 3 As shown, the protective layer 101 covers the outer circumference of the body 105 facing away from the first cavity 100 and the end surfaces 103 of the body 105 at opposite ends along the axial direction. The outer surface of the body 105 facing away from the first cavity 100 can be understood as other surfaces except the cavity surface of the first cavity 100, and can include the outer circumference of the body 105 facing away from the first cavity 100 covered by the protective layer 101, and the end surfaces 103 at opposite ends along the axial direction L facing away from the first cavity 100, and are not "opposite" surfaces in an absolute sense. Figure 6 and Figure 7 As shown, a portion of the rotating shaft 2 passes through the first cavity 100 . The gap cavity 104 is the remaining cavity where the rotating shaft 2 extends into the first cavity 100 and is not occupied by the rotating shaft 2 .

[0060] In some embodiments of the present application, Figure 5 and Figure 6 As shown, the rotor assembly seals the gap cavity 104 between the permanent magnet 1 and the rotating shaft 2 at opposite ends along the axial direction L from the outside through the sealing connector 12. The sealing connector 12 seals the gap cavity at opposite ends along the axial direction L of the gap cavity 104. The sealing connector 12 is sealed with the protective layers 101 at both ends of the gap cavity 104 respectively. The sealing connector 12 is combined with the protective layer 101 on the outer surface of the main body 105 facing away from the first cavity 100, so that the inner surface of the first cavity of the main body is sealed, and then the surface of the main body is sealed and isolated from the external environment, which can effectively protect the permanent magnet from corrosion, and thus there is no need to set a protective layer on the inner surface of the first cavity of the permanent magnet. Therefore, compared with setting a protective layer which will result in a larger inner diameter tolerance of the inner surface of the first cavity of the permanent magnet, the sealing connector that blocks the gap cavity along the opposite ends of the gap cavity is sealed with the protective layers at both ends respectively, and the protective layer is not required to be set on the inner surface of the first cavity of the permanent magnet, thereby effectively reducing the inner diameter tolerance of the first cavity, so that the surface of the permanent magnet in the first cavity where the protective layer is not set can maintain a higher machining accuracy as machined, so that the permanent magnet can be assembled with the rotating shaft with higher accuracy into a precise rotor assembly, thereby improving the yield of the motor assembled by the rotor assembly.

[0061] It should be noted that if Figure 6 As shown, the permanent magnet 1 and the rotating shaft 2 are in contact connection before the sealing connection body 12 is not sealed and filled, but a gap cavity 104 is formed in the partial area corresponding to the first cavity 100, as shown in FIG. Figure 5 As shown, the gap cavity 104 is actually smaller. Figures 6 to 10 The gap cavity 104 is enlarged in the rotor assembly shown to schematically illustrate the structure between the permanent magnet, the rotating shaft, and the sealing connector and the protective layer. The presence of the gap cavity 104 will cause the inner surface of the permanent magnet 1 connected to the rotating shaft 2 to be exposed, which may cause the permanent magnet made of magnetic steel to corrode. Therefore, it is necessary to use a sealant or adhesive to form a sealing connector to seal the gap cavity at least at both opposite ends along the axial direction L, and to seal the sealing connector 12 to the protective layers 101 at both ends, so that the surface of the main body 105 is isolated from the external environment, preventing the surface of the permanent magnet 1 connected to the rotating shaft 2 from being corroded.

[0062] In the embodiments of the present application, Figure 1 and Figure 2 As shown, the inner diameter d1 of the first cavity 100 enclosed by the main body 105 of the permanent magnet 1 is generally 0.3mm to 2.0mm, the outer diameter d2 of the permanent magnet is generally 0.8mm to 6.0mm, and the length of the permanent magnet 1 is 3mm to 30mm. Since the processing accuracy of the inner surface (i.e., the inner diameter surface) of the first cavity 100 of the permanent magnet 1 is not affected by the protective layer 101, the smaller the value of the inner diameter tolerance of the first cavity 100 of the permanent magnet 1, the higher its processing accuracy, that is, the higher the accuracy of the inner diameter tolerance, which can reach up to 0.005mm. As a result, the permanent magnet can be assembled with the rotating shaft 2 to form a rotor assembly with higher precision, and applied to a precision blood pumping motor, thereby improving the assembly yield of the motor, so that the motor including the rotor assembly can meet the precision requirements of the ventricular assist blood pumping device and be placed in the human body's blood vessels to pump blood.

[0063] In some embodiments of the present application, protective layer 101 comprises one or a composite layer of two or more of the following: a surface passivation layer, a zinc coating, a nickel coating, a copper coating, an epoxy coating, a vacuum aluminum coating, a sprayed zinc-aluminum coating, and a parylene coating. Protective layer 101 protects the outer surface of the permanent magnet 1, which faces away from the first cavity 100, from corrosion, allowing the permanent magnet to maintain a stable connection with the shaft and perform its function. The protective layer formed by combining multiple coatings, a surface passivation layer or an electrophoretic epoxy coating, and a sprayed zinc-aluminum coating can effectively improve the corrosion resistance of the permanent magnet surface, meeting its corrosion resistance requirements.

[0064] In some embodiments of the present application, the thickness of the protective layer 101 is 0.003 mm to 0.300 mm. For example, the thickness of the protective layer 101 may be 0.004 mm, 0.005 mm, 0.007 mm, 0.008 mm, 0.100 mm, 0.150 mm, 0.200 mm, 0.240 mm, 0.250 mm, 0.260 mm, 0.270 mm, 0.280 mm, 0.290 mm, or 0.300 mm. In other embodiments, the thickness of the protective layer 101 is 0.120 mm, or 1.270 mm. In some embodiments of the present application, if the protective layer is a metal plating layer such as Ni, Cu, or Al, the thickness is generally 0.003 mm to 0.030 mm. If the protective layer is a non-metallic layer, such as an epoxy coating or a parylene coating, the thickness is generally 0.005 mm to 0.100 mm.

[0065] In some embodiments of the present application, the inner diameter tolerance of the first cavity 100 formed by the permanent magnet 1 enclosed by the body 105 is ≤0.02mm, and the concentricity of the first cavity 100 formed by the permanent magnet 1 enclosed by the body 105 is ≤0.015mm. For a permanent magnet that meets the above-mentioned inner diameter tolerance and concentricity requirements, the machining accuracy of the inner diameter tolerance and concentricity is improved from 0.05mm to less than 0.02mm and less than 0.015mm, respectively, so that the machining accuracy of the inner diameter and concentricity of the first cavity of the permanent magnet is greatly improved. The motor shaft itself is a high-precision part (the tolerance range of the outer diameter d3 of the shaft is within 0.005mm, especially within 0.002mm). Therefore, it is easier to obtain a high-precision and high-concentricity rotor assembly during assembly, thereby significantly reducing the assembly defect rate of the motor. The permanent magnet has high inner diameter tolerance processing accuracy and high concentricity processing accuracy (≤0.02mm), which significantly reduces the fluctuation range of the assembled motor characteristics. At the same time, the motor's electric imbalance is suppressed, the vibration and noise level is reduced, and the quality of the motor is significantly improved.

[0066] In some embodiments of the present application, the outer diameter of the permanent magnet is 0.8mm to 6.0mm, the outer diameter tolerance of the permanent magnet 1 is ≤0.03mm, the length of the permanent magnet is 3mm to 30mm, and the length tolerance of the permanent magnet 1 is ≤0.04mm. After forming a protective layer on the outer surface of the body away from the first cavity, the permanent magnet that meets the above outer diameter tolerance and length tolerance requirements can maintain a high dimensional accuracy as a whole and be assembled with the rotating shaft into a precision motor for pumping blood or blood products. Exemplarily, the outer diameter d2 of the permanent magnet 1 can be 0.9mm, 1.0mm, 1.5mm, 2.0mm, 2.4mm, 3.0mm, 3.6mm, 4.0mm, 4.2mm, 5.0mm, 5.5mm, 5.8mm. The outer diameter tolerance of the permanent magnet 1 can be 0.025mm, 0.02mm, 0.015mm. The length of the permanent magnet 1 can be 4 mm, 5 mm, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 25 mm, 28 mm, or 30 mm. The length tolerance of the permanent magnet 1 can be 0.03 mm, 0.025 mm, or 0.02 mm.

[0067] In some embodiments of the present application, the permanent magnet and the protective layer that meet the above-mentioned dimensions can improve the processing accuracy of the outer diameter tolerance and the length tolerance of the permanent magnet from 0.05mm to 0.03mm. If the thickness of the protective layer is precisely controlled, the processing accuracy of the outer diameter tolerance and the length tolerance of the permanent magnet can be improved to 0.01mm, so that the permanent magnet has better dimensional accuracy, so that it can be assembled with the rotating shaft with higher processing accuracy to form a precise rotor assembly, and the rotor assembly can be assembled with the stator assembly to obtain a precise motor, thereby improving the yield of the motor assembly.

[0068] In some embodiments of the present application, Figure 4 and Figure 1 、 Figure 2 As shown, the rotating shaft 2 is cylindrical, and the first cavity 100 of the permanent magnet 1 is correspondingly a cylindrical cavity.

[0069] In other embodiments of the present application, the cross-section of the rotating shaft 2 perpendicular to its long axis is an N-gon, where N is a positive integer greater than or equal to 6. For example, N is a 6-, 8-, 12-, or 16-gon polygon to ensure stable connection between the rotating shaft and the permanent magnet. For an N-gon rotating shaft, the first cavity 100 can be configured as a 6-, 8-, 12-, or 16-gon polygon. The long axis is the central axis of the rotating shaft 2 along the axial direction L.

[0070] In some embodiments of the present application, the outer diameter tolerance of the rotating shaft 2 is ≤0.005mm. This allows the rotating shaft 2, as a high-precision component, to be assembled with the permanent magnets having the above-described structure into a compact rotor assembly, thereby improving the assembly yield of the motor. In some embodiments, the outer diameter tolerance of the rotating shaft 2 is ≤0.002mm, enabling assembly with the permanent magnets into a more precise rotor assembly.

[0071] In some embodiments of the present application, the sealing connector 12 is formed by an adhesive that at least partially or completely fills the gap cavity 104. It is understood that the sealing connector 12 can be provided inside, outside, or both inside and outside the gap cavity 104 at opposite ends along the axial direction L, so as to seal and fill the gap cavity 104 at opposite ends along the axial direction, and in combination with the protective layer 101, isolate the surface of the body 105 from the external environment to prevent corrosion of the permanent magnet.

[0072] In some embodiments of the present application, the inner surface of the permanent magnet 1, which forms the gap cavity 104 with the rotating shaft 2, can be machined to an accuracy of less than 0.015 mm. This allows the permanent magnet to be assembled with the rotating shaft with high precision, improving the yield rate of the rotor assembly and, in turn, the yield rate of the assembled motor. Furthermore, the inner diameter tolerance of the inner surface of the high-precision permanent magnet is small, resulting in a relatively small fluctuation range in the motor's characteristics. This also makes it easier to control the motor's dynamic unbalance and reduces the motor's vibration and noise.

[0073] In some embodiments of the present application, the interiors of the two opposite ends of the sealing connecting body 12 along the axial direction L at least partially block the gap cavity 104 .

[0074] In some embodiments of the present application, Figure 7 As shown, the sealing connector 12 is respectively filled in the interior of the gap cavity 104 at the opposite ends along the axial direction L, so that the gap cavity 104 is blocked by the opposite ends inside the gap cavity 104, and the sealing connector 12 is respectively sealed and connected to the protective layer 101 at the opposite ends of the axial direction L, so that the surface of the main body 105 is isolated from the external environment, preventing the permanent magnet from being corroded, and also enabling the permanent magnet 1 to be assembled with the rotating shaft 2 with higher precision into a precise rotor assembly, thereby improving the yield of the motor including the rotor assembly.

[0075] Optionally, in some embodiments, the sealing connector 12 fills the interior of the gap cavity 104 at the two opposite ends along the axial direction L, and each portion occupies 1 / 5 to 1 / 2 of the length of the gap cavity 104, so as to seal and fill the gap cavity between the permanent magnet and the rotating shaft from the two opposite ends in the axial direction to varying degrees, so that the main body 105 is isolated from the external environment and the permanent magnet is prevented from being corroded. Exemplarily, the length of each portion of the sealing connector 12 filling the gap cavity at both ends can independently be 1 / 5 to 1 / 2 of the length of the gap cavity. Optionally, the sealing connector 12 is respectively arranged at the interior of the gap cavity 104 at the two opposite ends along the axial direction L, and each portion occupies 2 / 5 and 1 / 3 of the length of the gap cavity 104. Alternatively, refer to Figure 7 The sealing connector 12 at the left end may occupy 1 / 5 of the length of the gap cavity 104, and the sealing connector 12 at the right end may occupy 1 / 2 of the length of the gap cavity 104. Alternatively, the sealing connector 12 at the left end may occupy 1 / 5 of the length of the gap cavity 104, and the sealing connector 12 at the right end may occupy 1 / 3 of the length of the gap cavity 104.

[0076] In some embodiments of the present application, Figure 8 As shown, the sealing connector 12 fills the entire gap cavity 104, and the sealing connector is sealed and connected to the protective layer 101 at the opposite ends of the axial direction L, so that the gap cavity 104 where the rotating shaft 2 extends into the overlapping section of the permanent magnet 1 is sealed and filled as a whole by the sealing connector, completely isolating the surface of the main body 105 from the external environment to prevent the permanent magnet from being corroded, and also enabling the permanent magnet 1 to be assembled and connected with the rotating shaft 2 with higher precision to obtain a precise rotor assembly, thereby improving the yield of the motor including the rotor assembly.

[0077] In some embodiments of the present application, Figure 9 As shown, a first transition fillet R is provided on the outside of the sealing connector 12, and the first transition fillet R is concave toward between the permanent magnet 1 and the rotating shaft 2, and the radius of the first transition fillet R is 0.3t to 2t, wherein t is the radial wall thickness of the main body 105. It should be noted that the radial wall thickness d of the main body 105, d = (d2-d1) / 2, is the thickness from the inner surface of the first cavity 100 of the main body 105 to the outer surface of the main body 105. Providing the first transition fillet R on the outside of the sealing connector 12 can further connect the sealing connector 12 with the rotating shaft 2 and the protective layer 101 at both ends along the axial direction L, thereby enhancing the connection stability of the sealing connector 12, and at the same time, the sealing connector can be connected to the protective layer on the surface of the end face 103 as much as possible, thereby enhancing the sealing performance. It can be understood that, as Figure 6 、 Figure 10 As shown, the first transition fillet R is applicable to the solution of externally blocking the gap cavity 104. In addition, the first transition fillet R can also be applicable to the solution of internally blocking the gap cavity 104, which will not be described in detail here.

[0078] In some embodiments of the present application, the permanent magnet 1 is provided with a recess 102 at least at one end of the two opposite ends along the axial direction L, and the recess 102 is concavely arranged from the end face of the permanent magnet 1 to the side of the permanent magnet 1 close to the first cavity 100, and the sealing connector 12 covers the recess 102 and is sealed and connected to the protective layer 101 to isolate the surface of the body 105 from the external environment and prevent the permanent magnet from being corroded. At the same time, the inner surface of the permanent magnet does not need to be provided with a protective layer, and the permanent magnet 1 can be assembled into a precise rotor assembly with a higher processing accuracy and the rotating shaft, thereby improving the yield rate of the motor assembled with the rotor assembly. At the same time, the provision of the recess 102 can increase the contact area between the sealing connector 12 and the permanent magnet 1 as a whole, so that the connection strength and sealing performance of the sealing connector and the permanent magnet are enhanced, so that the rotor assembly can operate more stably. It should be noted that the end face of the permanent magnet 1 refers to the end surface of the end face 103 of the body 105 partially or completely covered with the protective layer 101.

[0079] In some embodiments of the present application, Figure 9 As shown, the recess 102 is provided at at least one of the two opposite ends of the body 105 along the axial direction L. The recess 102 is recessed from the end face 103 of the body 105 toward the side of the body 105 close to the first cavity 100. The protective layer 101 at least partially covers the recess 102, and the sealing connector 12 covers the protective layer 101 of the recess 102 and is sealed to the protective layer 101. It is understood that in some embodiments, the protective layer of the end face 103 of the body 105 may not cover the recess 102, but the sealing connector 12 covers the recess 102 and is sealed to the protective layer 101 of the end face 103 of the body 105, so as to isolate the surface of the body 105 from the external environment and prevent the permanent magnet from being corroded. As a result, the permanent magnet 1 can be assembled with the rotating shaft to form a precise rotor assembly with high processing accuracy, thereby improving the yield rate of the motor assembled with the rotor assembly. At the same time, the provision of the recess 102 can increase the contact area between the sealing connector 12 and the main body 105 and even the permanent magnet 1 as a whole, and through reasonable structural design, the connection strength and sealing performance of the sealing connector and the permanent magnet 1 are enhanced, so that the rotor assembly can operate more stably.

[0080] It is understood that in other embodiments of the present application, the recess 102 is formed by a protective layer 101 covering at least one end face 103 of the two opposite ends of the body 105 along the axial direction L, and is concavely arranged toward the side of the permanent magnet 1 close to the first cavity 100. The sealing connector 12 covers the recess 102 and is sealed and connected to the protective layer 101, so that the surface of the body 105 is isolated from the external environment and prevents the permanent magnet from being corroded. In other embodiments, the recess 102 is concavely arranged from the end face 103 of the body 105 toward the side of the body 105 close to the first cavity 100, and the protective layer 101 with uniform layer thickness covers the recess 102, and the recess 102 after blocking the protective layer 101 still presents a concave form, and the sealing connector 12 covers the protective layer 101 corresponding to the recess 102, and is sealed and connected to the protective layer 101 of the end face 103 of the body 105, so that the surface of the body 105 is isolated from the external environment and prevents the permanent magnet from being corroded. This allows the permanent magnet 1 to be assembled with the rotating shaft to form a precise rotor assembly with high machining accuracy, thereby improving the yield rate of the motor assembled with the rotor assembly. Furthermore, the provision of the recess 102 can increase the overall contact area between the sealing connector 12 and the permanent magnet 1. Furthermore, through reasonable structural design, the connection strength and sealing performance between the sealing connector and the permanent magnet 1 are enhanced, thereby enabling more stable operation of the rotor assembly.

[0081] In some embodiments of the present application, Figure 9 As shown, the recess 102 protrudes toward the sealing connection body to form a second transition fillet R1 , and the radius of the second transition fillet R1 is 0.1t-0.75t, wherein t is the radial wall thickness of the body 105 , and the radial wall thickness of the body 105 is defined as above.

[0082] It is understandable that the recess 102 can be provided in a scheme in which the gap cavity 104 is blocked from the outside, in a scheme in which the gap cavity 104 is blocked from the inside, or in a scheme in which the gap cavity is blocked by a combination of the inside and the outside. By connecting the sealing connector 12 from the inside of the end to the outside of the end and covering the recess 102 to the protective layer 101 to block the gap cavity 104, the inner surface of the first cavity of the permanent magnet 1 can be sealed by the sealing connector and the protective layer, isolated from the external environment, so as to enhance the connection strength between the permanent magnet and the rotating shaft, seal the inner surface of the first cavity of the permanent magnet more tightly and firmly, and prevent the permanent magnet from being corroded. It can also enable the permanent magnet 1 and the rotating shaft 2 to be assembled into a rotor assembly with higher precision, thereby improving the yield rate of the motor.

[0083] In some embodiments, since the gap cavity 104 is filled with the sealed connection body 12 formed by the adhesive or sealant, Figures 8 and 9 The interstitial cavity 104 cannot be directly observed in the figure.

[0084] In some embodiments, a protective layer 101 is provided on a portion of the end surface 103 of the body 105 , and the sealing connector 12 is sealed along the boundary of the end surface 103 and the protective layer 101 .

[0085] In some embodiments, as Figure 6 、 Figure 9 As shown, the sealing connector 12 is in contact with the protective layer 101 along the end surface 103 of the body 105, so that the sealing connector is sealed at the boundary between the end surface 103 of the body 105 and the protective layer 101, isolating the surface of the body 105 from the external environment and preventing corrosion of the permanent magnet. As previously mentioned, in some embodiments, the protective layer 101 is arranged in an annular shape on a portion of the end surface 103 of the body 105, and the sealing connector 12 can be in contact with the protective layer along the end surface 103 of the body 105.

[0086] In some embodiments, as Figure 10 As shown, the sealing connector 12 covers the protective layer 101 of the end face 103 of the main body 105 and is sealedly connected to the protective layer 101. As mentioned above, the protective layer 101 is arranged in a ring shape on a partial area or the entire surface of the end face 103 of the main body 105. Exemplarily, the sealing connector 12 can cover the protective layer 101 of a partial area or the entire surface of the end face 103 and be sealedly connected to the protective layer 101. While the protective layer 101 protects the main body 105 made of magnetic steel, a more rigorous connection structure in which the protective layer and the sealing connector are superimposed on each other is further formed by the sealing connector covering the protective layer to prevent the permanent magnet from being corroded. In addition, the sealing connector 12 covers the protective layer and is sealed, which can further enhance the connection strength between the sealing connector and the protective layer, so that the rotating shaft and the permanent magnet are more stably connected.

[0087] In some embodiments, the protective layer 101 covers a portion of the recess 102 , and the sealing connector 12 covers the protective layer in the recess 102 to form a tighter protective structure.

[0088] In other embodiments of the present application, the sealing connector 12 extends from the interior of the two opposite ends of the gap cavity 104 along the axial direction L to the exterior of the two opposite ends of the gap cavity 104 along the axial direction L to seal the gap cavity 104. The sealing connector 12 fills the interior of the two opposite ends of the gap cavity 104 along the axial direction L and extends to the exterior of the two opposite ends of the gap cavity 104 along the axial direction L. A first transition fillet R is formed on the outside of the sealing connector 12, and the sealing connector 12 is sealed and connected to the protective layer 101 at both ends, that is, Figure 6 and Figure 7 A combined solution forms a partially hollow gap cavity 104 around the rotating shaft 2 to prevent the permanent magnet from being corroded and enables the inner surface of the permanent magnet 1 to be assembled and connected to the rotating shaft 2 with higher precision, thereby improving the yield rate of motor assembly.

[0089] In other embodiments of the present application, Figure 9 As shown, the sealing connector 12 fills the entire gap cavity 104 and extends to the outside of the two opposite ends of the gap cavity 104 along the axial direction L. A first transition fillet R is formed on the outside of the sealing connector 12, which is sealed and connected to the protective layer 101 at both ends, respectively, to seal the two opposite ends of the gap cavity 104 along the axial direction L as a whole, and to connect more completely with the protective layer 101. The surface of the main body 105 is isolated from the external environment by the sealing connector 12 and the protective layer 101, preventing the permanent magnet from being corroded, so that the permanent magnet 1 can be assembled with the rotating shaft 2 into a rotor assembly with higher precision, thereby improving the yield of the motor assembled by the rotor assembly.

[0090] In an embodiment of the present application, when forming a protective layer 101 covering the body 105 facing away from the first cavity, the first cavity 100 of the permanent magnet can be partially or completely sealed in advance using an inner diameter plug made of a non-metallic material such as silicone or fluoropolymer that is resistant to 180°C or above. Then, by surface passivation, zinc plating, nickel plating, copper plating, vacuum aluminum plating, zinc-aluminum spraying, epoxy resin plating, etc., a protective layer 101 composed of a single or multiple coatings and / or resin layers is formed on the outer surface of the body 105 of the permanent magnet 1 facing away from the first cavity 100, thereby improving the protective ability of the outer surface of the permanent magnet made of magnetic steel facing away from the first cavity and meeting the corrosion resistance requirements. Since the inner diameter surface of the permanent magnet in the first cavity is not protected by the composite protective layer 101, it is necessary to assemble it with the rotating shaft as soon as possible, and use an adhesive to fill and seal it to form a sealed connector 12, thereby sealing and protecting the inner diameter surface of the permanent magnet and the rotating shaft where the protective layer is not formed to prevent it from being corroded.

[0091] In an embodiment of the present application, a permanent magnet made of magnetic steel adopts the above-mentioned manufacturing process. Taking the protective layer of the permanent magnet as a composite protective layer of nickel-copper-nickel as an example, the outer diameter and length tolerance range of the permanent magnet containing the composite protective layer can be reduced from 0.05mm to 0.03mm. If the thickness of the nickel-copper-nickel plating layer is accurately controlled, the outer diameter and length tolerance range of the permanent magnet containing the composite protective layer can be reduced from 0.05mm to 0.01mm, thereby improving their respective dimensional accuracy. The inner diameter tolerance range and concentricity of the permanent magnet in the first cavity are reduced from 0.05mm to ≤0.02mm and 0.015mm respectively, thereby improving their respective dimensional accuracy. Since the inner diameter accuracy of the permanent magnet on the inner surface of the first cavity is not affected by the protective layer, the smaller the inner diameter tolerance of its inner diameter, the higher the machining accuracy of the inner diameter, which can reach up to 0.005mm. Because the machining accuracy and concentricity of the inner surface of the permanent magnet have been greatly improved, the motor shaft itself is also a part with high-precision dimensions (the tolerance of the shaft outer diameter is ≤0.005mm, especially ≤0.002mm). Therefore, when assembling the rotor assembly of the motor including the shaft and the permanent magnet, it is relatively easy to obtain a high-precision (high concentricity) assembly, which can significantly reduce the motor assembly defect rate and the fluctuation range of the motor characteristics. At the same time, the dynamic unbalance of the motor is suppressed, the vibration level is reduced, and the quality of the motor is significantly improved.

[0092] In a second aspect, the present application provides a motor, comprising: the above-mentioned rotor assembly and stator assembly, wherein the rotor assembly is rotatably mounted inside the stator assembly.

[0093] In some embodiments of the present application, Figure 11 As shown, the stator assembly includes: a winding 4, which encloses a second cavity 400, and the winding 4 and the permanent magnet 1 are coaxially arranged on the outside of the permanent magnet 1 with a preset gap 401; an iron core 5, which encloses a third cavity 500, and at least part of the winding is arranged in the third cavity 500; a proximal bearing 6, which is sleeved on the proximal end 201 of the rotating shaft 2 and is located at the first end 402 of the winding 4; a distal shaft seat 7, including a mounting cavity 700, and the distal shaft seat 7 is arranged on the side of the second end 403 of the winding 4 opposite to the first end 402 along its own length direction, and is connected to the iron core 5; a distal bearing 8, which is sleeved on the distal end 200 of the rotating shaft 2 opposite to the proximal end 201, and is located in the mounting cavity 700.

[0094] It should be noted that in this application, the proximal shaft end, distal shaft end, proximal bearing, distal shaft seat, distal bearing and other components are defined by the distance between the rotor assembly and the motor and the operator. The end close to the operator is defined as the proximal shaft end and the proximal bearing, and correspondingly, the end away from the operator is defined as the distal shaft end, the distal shaft seat, and the distal bearing.

[0095] The motor of the embodiment of the present application can be used as a blood pumping motor for pumping blood. In the embodiment of the present application, the rotor assembly is sleeved within the inner cavity of the stator assembly. The rotor assembly is composed of permanent magnets forming a permanent magnetic field. The stator assembly generates an excitation magnetic field by sequentially supplying power to the windings through a motor drive controller. The interaction between the permanent magnetic field and the excitation magnetic field causes the motor to rotate at high speed, driving the impeller connected to the distal end of the rotating shaft to rotate at high speed to pump blood. Both the distal and proximal bearings can be either sliding bearings or rolling bearings.

[0096] In some embodiments of the present application, Figure 11 As shown, the rotating shaft 2 is connected to the proximal bearing 6 and the distal bearing 8 in sequence from the proximal end 201 to the distal end 200. The proximal bearing 6 and the distal bearing 8 support the rotating shaft 2 so that it can rotate stably under the drive.

[0097] In the embodiment of the present application, the preset gap 401 between the winding 4 and the permanent magnet 1 can be set according to the size and requirements of the motor. For example, the preset gap can be 0.3mm, 0.5mm, or 1mm, which is not explicitly limited in the present application.

[0098] In some embodiments of the present application, the motor further includes a housing 9 , which encloses the proximal bearing 6 and the iron core 5 , and the distal shaft seat 7 is connected to an end of the housing 9 facing away from the proximal bearing 6 .

[0099] In a third aspect, an embodiment of the present application provides a ventricular assist blood pumping device, such as Figure 11 As shown, it includes the above-mentioned motor and impeller 3; the impeller 3 is connected to the distal end of the rotating shaft 2; and a conduit 10, which is connected to the motor to form a circulation channel 11. The conduit 10 is provided with a liquid inlet 10a and a liquid outlet 10b connected to the circulation channel 11, and the impeller 3 is located in the circulation channel 11.

[0100] In some embodiments of the present application, the conduit 10 covers the distal shaft seat 7 and the impeller 3 and is connected to the casing 9 . Figure 11 The arrows in the figure indicate the direction of blood flow pumped by the motor.

[0101] In some embodiments of the present application, the impeller 3 is sleeved on the distal end 200 of the rotating shaft 2, and the impeller 3 and the distal end of the rotating shaft 2 can be connected by bonding or insert injection molding.

[0102] In some embodiments of the present application, the motor is a three-phase permanent magnet brushless motor (the motor drive control is external to the motor, not shown). The distal end 200 of the motor shaft 2 is connected to the impeller 3, which is integrated with the catheter 10 to form a ventricular assist pumping device. Driven by the motor, the impeller 3 rotates at high speed to pump blood, causing the blood to be pumped through the circulation channel 11 and the liquid outlet 10b to the target location or container.

[0103] The above description is only a specific embodiment of the present application. Those skilled in the art will clearly understand that for the convenience and brevity of description, the specific working process described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. It should be understood that the scope of protection of the present application is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the scope of protection of this application.

Claims

1. A rotor assembly, characterized in that: include: The permanent magnet comprises a body, a first cavity enclosed by the body, and a protective layer covering an outer surface of the body facing away from the first cavity; A rotating shaft, a portion of the rotating shaft extending into the first cavity, a gap cavity being formed between the portion of the rotating shaft and the permanent magnet, and two axially opposite ends of the rotating shaft respectively extending out of the permanent magnet; The sealing connector blocks the gap cavity at least at two opposite ends along the axial direction of the gap cavity, and the sealing connector is sealed with the protective layers at both ends respectively to isolate the surface of the body from the external environment.

2. The rotor assembly according to claim 1, wherein: The sealing connection body blocks the gap cavity at the outside of two opposite ends of the gap cavity along the axial direction.

3. The rotor assembly according to claim 2, wherein: A first transition fillet is provided on the outside of the sealing connector. The first transition fillet is concave toward between the permanent magnet and the rotating shaft, and has a radius of 0.3t to 2t, where t is the radial wall thickness of the body.

4. The rotor assembly according to claim 1, wherein: The sealing connection body at least partially blocks the gap cavity along the interior of the two opposite ends of the gap cavity in the axial direction.

5. The rotor assembly according to any one of claims 1 to 4, characterized in that: At least one of the two opposite ends of the permanent magnet along the axial direction is provided with a recessed portion, the recessed portion is recessed inwardly from the end surface of the permanent magnet toward the permanent magnet, and the sealing connector covers the recessed portion.

6. The rotor assembly according to claim 5, wherein: The recessed portion protrudes toward the sealing connection body to form a second transition fillet, and the radius of the second transition fillet is 0.1t to 0.75t, wherein t is the radial wall thickness of the body.

7. The rotor assembly according to claim 1, wherein: The protective layer is provided on a partial area of ​​the end surface of the body, and the sealing connector is sealed along the boundary of the end surface and the protective layer.

8. The rotor assembly according to claim 1, wherein: At least one or more of the following conditions are met: 1) The outer diameter of the permanent magnet is 0.8 mm to 6.0 mm; 2) The outer diameter tolerance of the permanent magnet is ≤0.03mm; 3) The inner diameter of the first cavity formed by the permanent magnet and the body is 0.3 mm to 2.0 mm; 4) The inner diameter tolerance of the first cavity formed by the permanent magnet and the body is ≤0.02 mm; 5) The concentricity of the first cavity formed by the permanent magnet and the body is ≤0.015 mm; 6) The length of the permanent magnet is 3 mm to 30 mm; 7) The length tolerance of the permanent magnet is ≤0.04mm; 8) The protective layer comprises a surface passivation layer, a zinc plating layer, a nickel plating layer, a copper plating layer, an epoxy plating layer, a vacuum aluminum plating layer, a sprayed zinc aluminum layer, and a parylene coating, or a composite layer formed by two or more thereof; 9) The thickness of the protective layer is 0.003 mm to 0.300 mm; 10) The outer diameter tolerance of the rotating shaft is ≤0.005mm; 11) The rotating shaft is cylindrical; 12) The cross-section of the rotating shaft perpendicular to its long axis is an N-gon, where N is a positive integer greater than or equal to 6; 13) The sealed connection body is formed by an adhesive.

9. A motor, characterized in that: include: A stator assembly and a rotor assembly according to any one of claims 1 to 8, wherein the rotor assembly is rotatably sleeved within the stator assembly.

10. A ventricular assist pumping device, characterized in that: include: The motor is the motor according to claim 9; and an impeller connected to the distal end of the rotating shaft; as well as A conduit is connected to the motor to form a circulation channel. The conduit is provided with a liquid inlet and a liquid outlet communicated with the circulation channel. The impeller is located in the circulation channel.

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