A driving structure and a blood pump having the same.

Abstract

This application discloses a drive structure and a blood pump having the same. The drive structure drives an impeller in the blood pump to rotate. The drive structure includes a motor stator and a motor rotor drive structure for connection to the impeller. The motor stator includes multiple iron cores wound with coils, and the motor rotor includes multiple magnets distributed circumferentially. The axial length of the iron cores is selected between 6 mm and 9 mm, the yoke height is selected between 1.5 mm and 2.5 mm, the number of turns of the coil wound on each iron core is selected between 145 and 155, and the axial length of the magnets is selected between 2 mm and 3.5 mm. Applying this application can reduce the warming effect on the blood, which is more conducive to preventing thrombus formation.

Description

Technical Field

[0001] This application relates to the field of medical device technology, specifically to a drive structure and a blood pump having the same. Background Technology

[0002] Blood pumps are commonly used medical devices that provide the power to flow blood. For example, the heart is the body's vital organ, and its main function is to power blood flow, transporting blood to all parts of the body. When a patient's heart malfunctions and cannot provide this power, the patient's life is in danger. A blood pump can be placed in the patient's heart to provide the power for the blood flow.

[0003] A blood pump typically comprises a drive structure, a transmission shaft, and an impeller. The drive structure rotates the transmission shaft, which in turn drives the impeller. The impeller's rotation draws blood from the pump's inlet to its outlet. In practical applications, blood pumps are generally required to have good anti-thrombotic capabilities and low damage to blood components. However, blood pumps based on relevant technologies still carry the risk of thrombosis during use. Utility Model Content

[0004] This application aims to address one of the technical problems in the related art to a certain extent. To this end, this application provides a drive structure and a blood pump having the same.

[0005] To achieve the above objectives, this application adopts the following technical solution: a drive structure for driving the impeller in a blood pump to rotate, the drive structure including a motor stator and a motor rotor for connecting to the impeller, the motor stator including a plurality of iron cores wound with coils, the motor rotor including a plurality of magnets distributed circumferentially; the axial length of the iron core is a selected value between 6mm and 9mm, the yoke height is a selected value between 1.5mm and 2.5mm, the number of turns of the coil wound on each iron core is a selected value between 145 and 155, and the axial length of the magnet is a selected value between 2mm and 3.5mm.

[0006] The application of this application has the following beneficial effects: By applying this drive structure to a blood pump and improving its structure, the drive structure can output a large torque with a small current flowing through the coil. Thus, only a small current needs to be flowed through the coil to meet the driving power required by the impeller. Because the current flowing through the coil is small, the overall heat generation of the drive structure is reduced, thereby reducing the warming effect on the blood and making it more conducive to preventing thrombus formation.

[0007] Optionally, the iron core has six sections and the magnets have four sections. Through experimental research, the inventors discovered that having six iron cores and four magnets, i.e., a stator slot to magnetic pole ratio of 6s / 4p, achieves better output torque and driving efficiency. Furthermore, it is less difficult to machine, and the selection of coil wire diameter and winding operation are relatively easy, making it easier to manufacture.

[0008] Optionally, the six iron cores are distributed at 60° intervals, and the six iron cores are divided into three groups. Each group of iron cores is formed by connecting two iron cores at 180° intervals, and the three groups of iron cores are respectively used to pass through the A phase, B phase and C phase of the three-phase alternating current.

[0009] Optionally, the line width of the coil is not less than 0.75 mm.

[0010] Optionally, the outer diameter of the motor stator is a selected value between 5.5 mm and 7 mm.

[0011] Optionally, the magnetization directions of two adjacent magnets along the circumference are opposite.

[0012] Optionally, the motor stator and the motor rotor are arranged at intervals along the rotation axis of the motor rotor.

[0013] To achieve the above objectives, this application also adopts the following technical solution: a blood pump, the blood pump comprising:

[0014] A shell having an inner cavity and a blood inlet and a blood outlet communicating with the inner cavity;

[0015] A drive shaft, rotatably disposed within the inner cavity; and,

[0016] An impeller is fixedly mounted on the drive shaft, and the impeller is located between the blood inlet and the blood outlet along the axial direction of the drive shaft;

[0017] The blood pump further includes a drive structure as described in any of the above technical solutions, wherein the drive structure is located within the inner cavity, and the motor rotor is fixedly connected to the transmission shaft to drive the impeller to rotate via the transmission shaft.

[0018] The beneficial effects of the blood pump provided in this application are consistent with the discussion of the beneficial effects of the aforementioned drive structure, and will not be repeated here.

[0019] Optionally, the blood pump further includes a bearing, which comprises an outer ring fixedly connected to the inner wall of the housing and an inner ring fixedly sleeved on the outside of the drive shaft. The outer ring and the inner ring are coaxial and radially spaced, and the outer ring and the inner ring are magnetically repelled to maintain the distance. The magnetic bearing achieves circumferential positioning of the drive shaft relative to the inner wall of the housing. This not only ensures the stability of the drive shaft during rotation but also prevents heat generation due to friction. Similarly, reduced heat generation decreases the warming effect on the blood, which is more conducive to preventing thrombus formation.

[0020] Optionally, both the outer ring and the inner ring are integral annular structures, and the magnetization directions of the outer ring and the inner ring are consistent; or, the outer ring includes a plurality of first annular bodies arranged sequentially along the axial direction, and the inner ring includes the same number of second annular bodies arranged sequentially along the axial direction as the first annular bodies, the axial dimensions of the second annular bodies are the same as the axial dimensions of the first annular bodies and they are arranged in a one-to-one correspondence along the radial direction, the magnetization directions of two adjacent first annular bodies along the axial direction are opposite, and the magnetization directions of the first annular bodies and their corresponding second annular bodies are the same.

[0021] These features and advantages of this application will be disclosed in detail in the following specific embodiments and accompanying drawings. The best embodiments or means of this application will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of this application. In addition, each of these features, elements and components appearing in the following text and drawings is multiple and is labeled with different symbols or numbers for convenience, but all represent parts with the same or similar structure or function. Attached Figure Description

[0022] The following description, in conjunction with the accompanying drawings, further illustrates this application:

[0023] Figure 1 A schematic diagram of the structure of a motor stator in a drive structure provided for the first aspect of this application;

[0024] Figure 2 This application provides a schematic diagram of the structure of a motor rotor in a drive structure.

[0025] Figure 3 A schematic diagram showing the distribution of magnets in a motor rotor of a drive structure provided in this application;

[0026] Figure 4 A schematic diagram of the structure of a blood pump provided for the second aspect of this application;

[0027] Figure 5 An exploded view of a blood pump provided in an embodiment of this application;

[0028] Figure 6A cross-sectional view of a blood pump provided in an embodiment of this application;

[0029] Figure 7 A schematic diagram of the blood pump operation provided in the embodiments of this application;

[0030] Figure 8 This is a simulation diagram of the drive structure in the blood pump provided in the embodiments of this application;

[0031] Figure 9 A simulation diagram of the driving structure provided for Comparative Example 1;

[0032] Figure 10 A simulation diagram of the driving structure provided for Comparative Example 2;

[0033] Figure 11 A simulation diagram of the driving structure provided for Comparative Example 3;

[0034] Figure 12 A simulation diagram of the driving structure provided for Comparative Example 4;

[0035] Figure 13 A simulation diagram of the driving structure provided for Comparative Example 5;

[0036] Figure 14 A simulation diagram of the driving structure provided for Comparative Example Six;

[0037] Figure 15 This is a schematic diagram of the drive shaft and impeller in the embodiment;

[0038] Figure 16 This is a schematic diagram showing that the drive shaft housing, drive shaft, and motor rotor form an integral structure in the embodiment.

[0039] Figure 17 This is a schematic diagram of the structure of a bearing in a blood pump according to one embodiment.

[0040] Among them, 1. Housing, 10. First housing, 100. Blood inlet, 101. First outlet, 11. Second housing, 110. Second outlet, 12. Third housing, 2. Drive shaft, 3. Impeller, 4. Motor stator, 40. Coil, 41. Iron core, 5. Motor rotor, 50. Magnet, 6. Bearing, 60. Outer ring, 600. First annular body, 61. Inner ring, 610. Second annular body, 7. Drive shaft housing, 8. Displacement sensor, 9. Conduit, 90. Circuit board. Detailed Implementation

[0041] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments in the implementation are intended to explain this application and should not be construed as limiting this application.

[0042] The terms "an embodiment," "example," or "example" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this application. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0043] Blood pumps provide the power for blood flow. In practical applications, blood pumps are generally required to have good anti-thrombotic capabilities and low damage to blood components. However, blood pumps in related technologies still pose a risk of thrombosis during use. The inventors have discovered that the risk of thrombosis in blood pumps during use is mainly due to two factors: the drive structure in the blood pump generates heat during operation, or the bearings on the external drive shaft of the blood pump generate heat through friction during operation. This heat raises the temperature of the blood flowing through the pump, making it more susceptible to thrombosis, especially at lower impeller speeds. The combined effect of these heating effects further increases the likelihood of thrombosis.

[0044] The first aspect of this application provides a drive structure that can be applied to a blood pump, and when applied to a blood pump, it can be used to drive the rotation of an impeller in the blood pump. For example... Figure 1 , Figure 2 and Figure 3 As shown, the drive structure includes a motor stator 4 and a motor rotor 5 for connection to the impeller in the blood pump. The motor stator 4 includes multiple iron cores 41 wound with coils 40, and the motor rotor 5 includes multiple magnets 50 distributed circumferentially. In this embodiment, the specific dimensions of the motor stator 4 and motor rotor 5 in the drive structure are also designed. Specifically, the axial length of the iron core 41 is a selected value between 6mm and 9mm, the yoke height is a selected value between 1.5mm and 2.5mm, the number of turns of the coils 40 wound on each iron core 41 is a selected value between 145 and 155, and the axial length of the magnets 50 is a selected value between 2mm and 3.5mm.

[0045] Applying the drive structure provided in this application to a blood pump, and through structural improvements, the drive structure can output a large torque while applying a small current to the coil 40. Thus, only a small current needs to be applied to the coil 40 to meet the driving power requirements of the impeller 3. Because the current flowing through the coil 40 is small, the overall heat generation of the drive structure is reduced, thereby decreasing the warming effect on the blood and making it more conducive to preventing thrombus formation.

[0046] The second aspect of this application provides a blood pump, such as Figure 4 , Figure 5 and Figure 6 As shown, the blood pump includes a housing 1, a drive shaft 2, an impeller 3, and a drive structure. The housing 1 has an inner cavity with a blood inlet 100 and a blood outlet communicating with it. The drive shaft 2 is rotatably disposed within the inner cavity. The impeller 3 is fixedly disposed on the drive shaft 2 and is located axially between the blood inlet 100 and the blood outlet along the drive shaft 2. The drive structure is located within the inner cavity and is used to drive the drive shaft 2 to rotate.

[0047] Combination Figure 7 As shown, when the blood pump is working, the drive structure drives the transmission shaft 2 to rotate, and the transmission shaft 2 drives the impeller 3 to rotate. When the impeller 3 rotates, it uses centrifugal force to cause blood to flow, thereby forming a low-pressure area. Then, the pressure is used to force external blood into the low-pressure area, so that blood can flow in from the blood inlet 100, flow through the inner cavity, and then be discharged from the blood outlet. Figure 3 As shown, the blood pump also has a displacement sensor 8 installed at the bearing. The displacement sensor 8 can monitor whether there is radial or axial displacement between the inner and outer rings of the bearing, thereby allowing timely judgment on whether the working status of the drive shaft is normal. A conduit 9 and a circuit board 90 are also provided at the tail of the housing 1. An external power supply can be electrically connected to the circuit board 90 through a wire passing through the conduit 9, and the circuit board 90 is electrically connected to the coil to energize the coil.

[0048] Combination Figures 8 to 14 As shown, Figure 8 The diagram shows a simulation schematic of the drive structure in the blood pump provided in this embodiment. Figures 9 to 14 The diagram shows comparative simulation schematics of six different drive structures. In this embodiment, the drive structure includes a motor stator and a motor rotor. The motor stator includes an iron core and coils wound around the iron core, while the motor rotor includes multiple magnets. Figure 9 The comparative example shown in the figure has a different magnet structure compared to the drive structure in this application; Figure 10 Compared with Comparative Example 1, Comparative Example 2 shows a different gap size between the iron cores. Figure 11The comparative example shown in the paper has a three-phase drive structure that does not have an iron core and has a different magnet structure compared to the drive structure in this application; Figure 12 Compared to Comparative Example 2, the coil in Comparative Example 3 has a shorter axial length. Figure 13 The comparative example shown in the paper does not have an iron core and the magnet size is different from the drive structure in this application; Figure 14 Compared to Comparative Example 5, the axial dimension of the magnet in Comparative Example 6 is longer.

[0049] Simulation tests were performed on the driving structure provided in this embodiment and the driving structures provided in Comparative Examples 1 to 6, and the following comparison results were obtained:

[0050]

[0051]

[0052] The drive structure in the blood pump provided in this embodiment can effectively balance both low current and high torque. Thus, only a small current needs to be applied to the coil while still meeting the driving power requirements of the impeller. Furthermore, in this embodiment, the axial length of the iron core is preferably designed to be 8mm, the yoke height to be 2mm, the number of turns of the coil wound around each iron core to be 150, and the axial length of the magnet to be 3mm. Of course, in optional embodiments, the axial length of the iron core can be selected from 6mm to 9mm, the yoke height from 1.5mm to 2.5mm, the number of turns of the coil wound around each iron core from 145 to 155, and the axial length of the magnet from 2mm to 3.5mm.

[0053] Furthermore, in this embodiment, six iron cores 41 and four magnets 50 are provided. Through experimental research, the inventors discovered that having six iron cores 41 and four magnets 50, i.e., a stator slot to magnetic pole ratio of 6s / 4p, achieves better output torque and drive efficiency while minimizing machining difficulty. The selection of the coil diameter and winding operation are relatively easy, facilitating production. Specifically, due to the limitation of the blood pump's outer diameter (its overall size is very small because it needs to be inserted into the body), the number of stator slots formed on the motor stator 4 must be selected considering both the need for greater torque output and the ease of machining. The outer diameter of the iron core 41 is positively correlated with torque. To obtain high torque, and to improve the power density of the drive structure while reducing losses, the motor slot fill factor is typically maximized. When three stator slots are chosen, the slot area is large, requiring a large number of turns in the coil 40 or a large wire diameter. This results in the coil 40 occupying a significant amount of radial space, limiting the diameter of the core 41. Conversely, fewer turns or a smaller wire diameter in the coil 40 reduces power density and efficiency. In this embodiment, the drive structure is an ultra-high-speed motor with a maximum speed of 45,000 rpm or higher. The motor's operating frequency is much higher than that of conventional motors. Since motor losses are positively correlated with the square of the frequency, a rotor with a lower number of stages should be selected to minimize losses. Therefore, setting three stator slots cannot meet the application requirements.

[0054] In summary, this embodiment uses six iron cores 41 and four magnets 50. This results in a moderate number of stator slots, achieving both a high slot fill factor and a large iron core diameter 41, thus enabling higher efficiency and torque. Furthermore, it does not significantly increase the difficulty of machining, which is beneficial for product manufacturing. In this embodiment, the six iron cores 41 are distributed at 60° intervals, forming three groups. Each group consists of two iron cores 41 connected at 180° intervals, and the three groups are used to supply the A-phase, B-phase, and C-phase of the three-phase AC power, respectively.

[0055] In addition, in this embodiment, the motor stator 4 and the motor rotor 5 are arranged at intervals along the rotation axis of the motor rotor 5. Specifically, the iron core 41 in the motor stator 4 and the magnets in the motor rotor 5 are arranged at intervals along the rotation axis of the motor rotor.

[0056] In this embodiment, the magnet 50 is a hollow rotor magnet 50, which reduces the weight of the magnet 50, decreases the moment of inertia, enables multi-pole magnetization, and facilitates segmented assembly. In this embodiment, the magnetization directions of two adjacent magnets 50 along the circumferential direction are opposite.

[0057] Furthermore, for this core 41 structure, the dimensions of the core 41 and the coil 40 can be optimized through simulation technology. In this embodiment, the line width of the coil 40 is not less than 0.75mm, and the outer diameter of the motor stator 4 is a selected value between 5.5mm and 7mm.

[0058] Furthermore, as mentioned earlier, the bearings mounted outside the drive shaft in blood pumps of related technologies also generate heat through friction during operation. To address this issue, the blood pump provided in this embodiment further includes a bearing 6, which is sleeved on the outside of the drive shaft 2. In this embodiment, the bearing 6 includes an outer ring 60 fixedly connected to the inner wall of the housing 1 and an inner ring 61 fixedly sleeved on the outside of the drive shaft 2. The outer ring 60 and the inner ring 61 are coaxial and radially spaced. The outer ring 60 and the inner ring 61 are magnetically repelled to maintain the distance. The magnetic bearing 6 achieves circumferential positioning of the drive shaft 2 relative to the inner wall of the housing 1. In this way, the drive shaft 2 can not only remain stable during rotation but also avoid heat generation due to friction. Reduced heat generation reduces the warming effect on the blood, which is more conducive to preventing thrombus formation.

[0059] Furthermore, in this embodiment, both the outer ring 60 and the inner ring 61 are integral annular structures; that is, the outer ring 60 is a single integral structure, and the inner ring 61 is also a single integral structure. Moreover, the magnetization directions of the outer ring 60 and the inner ring 61 are consistent, thus generating mutual repulsion. In other optional embodiments, such as... Figure 17 As shown, the outer ring 60 may include a plurality of first annular bodies 600 arranged sequentially along the axial direction, and the inner ring 61 may include the same number of second annular bodies 610 arranged sequentially along the axial direction as the first annular bodies 600. The axial dimensions of the second annular bodies 610 are the same as those of the first annular bodies 600, and they are arranged in a one-to-one radial correspondence. The magnetization directions of two adjacent first annular bodies 600 along the axial direction are opposite, and the magnetization directions of the first annular body 600 and its corresponding second annular body 610 are the same. A specific example is given below: four first annular bodies 600 and four second annular bodies 610 are provided, with each first annular body 600 corresponding to one second annular body 610.

[0060] The two different bearing 6 structure schemes mentioned above each have their advantages, and adopting such a scheme is preferable. Figure 10 The proposed solution generates a stronger magnetic force between the outer ring 60 and the inner ring 61, resulting in superior radial stiffness between them. This makes the rotation of the drive shaft 2 more stable. However, since both the outer ring 60 and the inner ring 61 are divided into multiple segments, the manufacturing cost is relatively high. Therefore, the bearing 6 solution provided in this embodiment can also be chosen, where both the outer ring 60 and the inner ring 61 are integral structures, making them easier to manufacture.

[0061] In this embodiment, the outer ring 60 has an outer diameter of 6.6 mm, an inner diameter of 5 mm, and an axial height of 2 mm; the inner ring 61 has an outer diameter of 3.2 mm, an inner diameter of 1 mm, and an axial height of 2 mm. Both the outer ring 60 and the inner ring 61 are made of NdFeB35 permanent magnet material, and the magnetization directions of the outer ring 60 and the inner ring 61 are the same, both being axially magnetized.

[0062] Combination Figure 2 and Figure 3 As shown, in this embodiment, the housing 1 includes a first housing 10, a second housing 11, and a third housing 12 arranged sequentially. The bearing 6 includes a first bearing and a second bearing. The drive shaft 2 is located inside the first housing 10 and the second housing 11. The first bearing is disposed inside the first housing 10, and the second bearing is disposed inside the second housing 11. The motor rotor 5 is located inside the second housing 11, and the motor stator 4 is located inside the third housing 12. Further, in conjunction with... Figure 15 and Figure 16 As shown, the blood pump also includes a drive shaft housing 7 located inside the housing 1, and the drive shaft housing 7, drive shaft 2 and motor rotor 5 are formed as an integral structure.

[0063] The blood outlet includes a first outlet 101 located on the first housing 10 and a second outlet 110 located on the second housing 11. By providing the first outlet 101 and the second outlet 110, the number of blood drainage points can be increased.

[0064] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Those skilled in the art should understand that this application includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of this application will be included within the scope of the claims.

Claims

1. A drive structure for driving the rotation of an impeller in a blood pump, characterized in that, The drive structure includes a motor stator (4) and a motor rotor (5) for connection with the impeller. The motor stator (4) includes a plurality of iron cores (41) wound with coils (40), and the motor rotor (5) includes a plurality of magnets (50) distributed circumferentially. The axial length of the iron core (41) is a selected value between 6 mm and 9 mm, the yoke height is a selected value between 1.5 mm and 2.5 mm, the number of turns of the coil (40) wound around each iron core (41) is a selected value between 145 and 155, and the axial length of the magnet (50) is a selected value between 2 mm and 3.5 mm.

2. The driving structure as described in claim 1, characterized in that, The iron core (41) is provided in six parts, and the magnet (50) is provided in four parts.

3. The driving structure as described in claim 2, characterized in that, The six iron cores (41) are distributed at 60° intervals. The six iron cores (41) are divided into three groups. Each group of iron cores (41) is formed by connecting two iron cores (41) at 180° intervals. The three groups of iron cores (41) are respectively used to pass through the A phase, B phase and C phase of the three-phase alternating current.

4. The driving structure as described in any one of claims 1 to 3, characterized in that, The line width of the coil (40) is not less than 0.75 mm.

5. The driving structure as described in claim 4, characterized in that, The outer diameter of the motor stator (4) is a selected value between 5.5 mm and 7 mm.

6. The driving structure as described in claim 1, characterized in that, The magnetization directions of two adjacent magnets (50) along the circumference are opposite.

7. The driving structure as described in claim 1, characterized in that, The motor stator (4) and the motor rotor (5) are arranged at intervals along the rotation axis of the motor rotor (5).

8. A blood pump, said blood pump comprising: The housing (1) has an inner cavity and a blood inlet (100) and a blood outlet communicating with the inner cavity; A drive shaft (2) is rotatably disposed within the inner cavity; and, An impeller (3) is fixedly mounted on the drive shaft (2), and the impeller (3) is located between the blood inlet (100) and the blood outlet along the axial direction of the drive shaft (2); The blood pump further includes a drive structure as described in any one of claims 1 to 6, wherein the drive structure is located within the inner cavity, and the motor rotor (5) is fixedly connected to the transmission shaft (2) to drive the impeller to rotate via the transmission shaft (2).

9. The blood pump as described in claim 8, characterized in that, The blood pump also includes a bearing (6), which includes an outer ring (60) fixedly connected to the inner wall of the housing (1) and an inner ring (61) fixedly sleeved on the outside of the transmission shaft (2). The outer ring (60) and the inner ring (61) are coaxial and radially spaced. The outer ring (60) and the inner ring (61) are magnetically repelled to maintain the distance.

10. The blood pump as described in claim 9, characterized in that, Both the outer ring (60) and the inner ring (61) are integral ring structures, and the magnetization directions of the outer ring (60) and the inner ring (61) are consistent. Alternatively, the outer ring (60) includes a plurality of first annular bodies (600) arranged sequentially along the axial direction, and the inner ring (61) includes the same number of second annular bodies (610) arranged sequentially along the axial direction as the first annular bodies (600). The axial dimension of the second annular bodies (610) is the same as that of the first annular bodies (600) along the axial direction, and the two are arranged in a one-to-one correspondence along the radial direction. The magnetization directions of two adjacent first annular bodies (600) along the axial direction are opposite, and the magnetization directions of the first annular bodies (600) and the corresponding second annular bodies (610) are the same.

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