A drive motor for a heart assist device and a heart assist device

Abstract

The application relates to a driving motor for a heart assisting device, which comprises a casing, a stator, a rotor and a rotating shaft; wherein the casing is cylindrical, the diameter of the casing is smaller than the inner diameter of a femoral artery or an aorta; the stator is a hollow cylinder coaxially arranged on the inner wall of the casing, and the stator comprises a stator core without a tooth structure and a hollow cup-shaped winding; the stator core comprises an iron-based amorphous alloy core, and an epoxy resin coating is arranged on the inner wall of the iron-based amorphous alloy core, which is used for electrically isolating and volume compensating the iron-based amorphous alloy core; the rotor is a columnar structure with a center through hole, and the rotor is coaxially arranged in the stator; the winding comprises a cup-shaped winding arranged between the stator and the rotor; the rotating shaft is arranged in and fixed to the rotor, and the two ends of the rotating shaft pass through the two ends of the rotor. The driving motor provided by the application is compact and stable in structure and high in power, and is especially suitable for a heart assisting device such as an axial flow pump.

Description

Technical Field

[0001] This invention relates to the field of medical devices for cardiac surgery, and more particularly to a drive motor for a cardiac assist device and a cardiac assist device. Background Technology

[0002] End-stage structural heart disease, coronary artery disease, and cardiogenic shock can lead to heart failure, resulting in insufficient blood flow from veins to arteries. Currently, some ventricular assist devices (or artificial hearts) available both domestically and internationally can provide the heart with independent blood supply, offering a solution for heart failure patients beyond heart transplantation. However, traditional ventricular assist devices require open-heart surgery, which carries high surgical risks. Furthermore, because implantation damages heart tissue, causing irreversible harm, traditional heart failure solutions still have significant limitations.

[0003] To address the aforementioned issues, novel percutaneous ventricular assist devices (VADs) have been rapidly developed and widely adopted. Compared to traditional VADs, VADs do not require open-heart surgery and can be implanted into the heart via minimally invasive methods such as femoral artery puncture or incision. Their main advantages include: percutaneous implantation significantly reduces surgical risks; and access to the ventricle via an artery avoids physical trauma to cardiac tissue, potentially allowing for the recovery of cardiac function. These advantages enable them to be used to maintain vital signs in patients with severe heart failure or as adjunctive therapy during high-risk percutaneous coronary intervention (PCI) procedures.

[0004] The micromotor within the axial flow pump is the core component of the ventricular assist device (VAD). Its function is to generate pressure by driving an impeller at high speed, pumping blood from the left ventricle into the aorta. This ensures that heart failure patients, despite insufficient cardiac function, still receive the necessary circulating blood flow to maintain their vital signs. Because it needs to be implanted into the left ventricle via the femoral artery, the casing material of the micromotor, which comes into direct contact with the patient, must meet biocompatibility requirements. Furthermore, the micromotor's dimensions are critical, with an outer diameter generally not exceeding 21Fr / 7mm. Simultaneously, to generate the necessary flow to maintain the patient's vital signs, the micromotor's rotational speed is required, typically reaching tens of thousands of revolutions per minute (rpm) under load. Therefore, the design of the micromotor within the axial flow pump is crucial to the performance and safety of the VAD.

[0005] For the reasons mentioned above, how to provide a compact, stable, and high-power micro motor suitable for axial flow pumps has become a pressing technical problem that needs to be solved. Summary of the Invention

[0006] This invention discloses a drive motor for a cardiac assist device and a cardiac assist device, aiming to solve the technical problems existing in the prior art.

[0007] The present invention adopts the following technical solution:

[0008] On one hand, the present invention provides a drive motor for a cardiac assist device, comprising: a housing, a stator, a rotor, and a shaft;

[0009] The casing is cylindrical, and its diameter is smaller than the inner diameter of the femoral artery or aorta.

[0010] The stator is hollow cylindrical and coaxially disposed on the inner wall of the housing. The stator includes a stator core without a toothed section and a hollow cup-shaped winding. The stator core includes an iron-based amorphous alloy core. The inner wall of the iron-based amorphous alloy core is provided with an epoxy resin coating. The epoxy resin coating is used to provide electrical isolation and volume compensation for the iron-based amorphous alloy core.

[0011] The rotor is a cylindrical shape with a central through-hole, and the rotor is coaxially installed in the stator;

[0012] The windings include cup-shaped windings, which are disposed between the stator and the rotor;

[0013] The shaft is inserted into and fixed in the rotor, with both ends of the shaft protruding from both ends of the rotor.

[0014] As a preferred technical solution, it also includes a front cover, a rear cover, a support component, and a sealing assembly;

[0015] The front cover is located at the front of the housing, and the pivot protrudes from the center of the front cover; the rear cover is located at the rear of the housing; both the front cover and the rear cover are fitted with the housing.

[0016] The sealing component is located between the front cover and the rotating shaft, and the sealing component slides with the rotating shaft.

[0017] The support components include a front bearing and a rear bearing, which are respectively located inside the front cover and the rear cover. The two ends of the rotating shaft pass through the front bearing and the rear bearing, respectively.

[0018] As a preferred technical solution, a PCB board is provided on the outer side of the rear end cover, and a three-phase lead wire is provided at the rear end of the winding. The three-phase lead wire passes through the rear end cover and is connected to one side of the PCB board, while the other side of the PCB board is connected to the three-phase cable.

[0019] As a preferred technical solution, a tail cover is also provided on the outside of the rear cover. The tail cover covers the PCB board, the three-phase cable and the rear cover. One side of the tail cover is sealed to the rear cover, and the other side of the tail cover is connected to a conduit. The three-phase cable is led out from the tail cover and placed in the conduit.

[0020] As a preferred technical solution, both the front cover and the rear cover are fitted with the casing; the tail cover is fitted with the rear cover.

[0021] As a preferred technical solution, the length-to-diameter ratio of the drive motor is 2 to 4:1; the diameter of the drive motor is not greater than 21Fr.

[0022] As a preferred technical solution, the hollow cup winding includes a copper cup structure wound with hot-melt self-adhesive enameled wire, and the hollow cup winding is fixed to the inside of the stator by epoxy resin.

[0023] As a preferred technical solution, the rotor includes a neodymium iron boron magnetic pole rotor.

[0024] As a preferred technical solution, bearing chambers are provided on the inner sides of both the front cover and the rear cover, with the front bearing and the bearing chamber of the front cover being overfitted together, and the rear bearing and the bearing chamber of the rear cover being overfitted together.

[0025] The front and rear bearings are the same size and are both open-type metal ball bearings.

[0026] As a preferred technical solution, the sealing assembly includes an inner ring seal and an outer ring retainer. The inner ring seal includes a fluororubber sealing ring that overfits with the rotating shaft, and the outer ring retainer includes a steel ring that overfits with the front end cover. The inner ring seal and the outer ring retainer are coaxially arranged.

[0027] On the other hand, this application provides a cardiac assist device, including a drive motor as described in any of the preceding claims, and further including an impeller, a cannula, and a pig tail tube; wherein the impeller is connected to the drive motor; the cannula is disposed on the outer periphery of the impeller, with one end of the cannula near the drive motor being an outflow chamber and the other end being an inflow chamber; the pig tail tube is connected to the inflow chamber.

[0028] The technical solution adopted in this invention can achieve the following beneficial effects:

[0029] (1) The present invention mainly provides a drive motor for a cardiac assist device. The drive motor adopts a design scheme of brushless DC permanent magnet motor. The brushless DC motor has no carbon brush structure, which reduces the cogging torque. Combined with the hollow cup-shaped winding, it can effectively improve the space utilization rate of the stator side, making the drive motor structure compact, reliable and stable. At the same time, it uses metal materials that meet the biocompatibility requirements as the housing, ensuring that it is not easily damaged even if it operates in human blood for a long time.

[0030] (2) The stator core of the drive motor is preferably made of iron-based amorphous alloy, which has high magnetic permeability and low loss characteristics, and its magnetic permeability is better than that of ordinary silicon steel. The rotor magnetic poles of the drive motor are preferably made of neodymium iron boron material, which can significantly improve the power density of the drive motor. Furthermore, in order to make up for the low saturation magnetic induction intensity of iron-based amorphous alloy, an electrical isolation is achieved by coating nano-epoxy resin between the stator core and the winding. Compared with the traditional insulating medium, the thickness can be reduced by more than 60%, and the space saved can provide more space for the volume of the stator core and the winding. This allows the stator and winding of iron-based amorphous alloy to reduce the magnetic flux density and DC resistance by increasing their own volume, without increasing the size of the drive motor.

[0031] (3) To prevent blood from entering the drive motor and obstructing its operation, a fluororubber sealing ring is installed between the front cover and the shaft. Due to the good elasticity and wear resistance of fluororubber, it can ensure low frictional resistance when the shaft rotates and ensure long-term reliability and sealing. The outer part of the sealing ring adopts a steel ring structure and is processed by an integrated injection molding process, which ensures the fitting accuracy and coaxiality between the sealing ring and the front cover, and greatly avoids performance degradation or even failure caused by form and position tolerances. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 This is a cross-sectional view of the drive motor in a preferred embodiment of the present invention as disclosed in Embodiment 1;

[0034] Figure 2 This is a schematic diagram of the winding structure in a preferred embodiment of the present invention as disclosed in Embodiment 1;

[0035] Figure 3 This is a schematic diagram of the stator structure in a preferred embodiment of the present invention as disclosed in Embodiment 1;

[0036] Figure 4 This is a schematic diagram of the sealing assembly in a preferred embodiment of the present invention, as disclosed in Embodiment 1.

[0037] Figure 5 for Figure 4 A partial cross-sectional view at point A in the middle;

[0038] Figure 6 This is a partial structural cross-sectional view of the sealing assembly in a preferred embodiment of the present invention, as disclosed in Embodiment 1.

[0039] Figure 7 This is a partial structural diagram of the drive motor in a preferred embodiment of the present invention, as disclosed in Embodiment 1 of the present invention;

[0040] Figure 8 This is a partial structural diagram of a cardiac assist device in a preferred embodiment of the present invention, as disclosed in Embodiment 2 of the present invention;

[0041] Figure 9 This is a schematic diagram of the structure of a cardiac assist device in a preferred embodiment of Embodiment 2 of the present invention;

[0042] Figure 10 This is a diagram showing the usage status of a cardiac assist device in a preferred embodiment of Embodiment 2 of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Housing; 2. Stator core; 3. Hollow cup winding; 4. Rotor; 5. Shaft; 6. Epoxy resin nano-coating; 7. Front cover; 8. Rear cover; 9. Tail cover; 10. Front bearing; 11. Rear bearing; 12. Fluororubber sealing ring; 13. Steel ring; 14. PCB board; 15. Conduit; 16. Three-phase lead wire; 17. Three-phase cable; 18. Drive motor; 19. Impeller; 20. Insertion tube; 21. Pig tail tube; 22. Inflow chamber; 23. Outflow chamber; 24. Left ventricle; 25. Aorta. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. In the description of this invention, it should be noted that the term "or" is generally used to include the meaning of "and / or," unless otherwise expressly indicated.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. Furthermore, in the description of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0047] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] To address the problems existing in the prior art, this application provides a drive motor for a cardiac assist device, comprising: a housing, a stator, a rotor, and a shaft; wherein the housing is cylindrical, and the diameter of the housing is smaller than the inner diameter of the femoral artery or aorta; the stator is hollow cylindrical and coaxially disposed on the inner wall of the housing, the stator comprising a toothless stator core and a hollow cup-shaped winding; the stator core comprises an iron-based amorphous alloy core, the inner wall of which is provided with an epoxy resin coating, the epoxy resin coating being used for electrical isolation and volume compensation of the iron-based amorphous alloy core; the rotor is a centrally penetrating column, coaxially disposed within the stator; the winding comprises a cup-shaped winding disposed between the stator and the rotor; the shaft is disposed and fixed within the rotor, with both ends of the shaft extending out from both ends of the rotor.

[0049] Example 1

[0050] This embodiment provides a drive motor for a cardiac assist device. In a preferred embodiment, the cardiac assist device refers to an axial flow pump, which includes components such as a drive motor 18, an impeller 19, a pigtail tube 21, and a cannula 20. In one embodiment, when using the cardiac assist device, it is implanted between the left ventricle 24 and the aorta 25 via an arterial pathway. The inflow end of the cardiac assist device is located in the left ventricle 24, allowing blood to be drained from the left ventricle 24 into the cardiac assist device. The outflow end of the cardiac assist device is located in the aorta 25. When the cardiac assist device is working, the blood entering the inflow end flows out from the outflow end into the aorta 25 under the drive of the rotating impeller 19 to maintain peripheral circulation. Therefore, the performance of the drive motor 18 is crucial to ensure that the impeller 19 in the cardiac assist device can rotate stably at high speed for a long time.

[0051] refer to Figures 1-7 Preferably, the drive motor 18 includes at least a housing 1, a stator core 2, a hollow cup-shaped winding 3, a rotor 4, a shaft 5, a front cover 7, a rear cover 8, a tail cover 9, a three-phase cable 17, a support component, and a sealing assembly. The entire drive motor 18 is cylindrical, and the rotor 4 passes through the shaft of the housing 1 and is connected to the impeller 19 to provide driving force.

[0052] Since the cardiac assist device needs to be implanted into the left ventricle 24 via an artery, the structural dimensions of the drive motor 18 are limited by the size of the artery. In a preferred embodiment, the housing 1 is cylindrical, and the diameter of the housing 1 is smaller than the inner diameter of the femoral artery or aorta 25. More preferably, the diameter of the housing 1 is designed to be no more than 21Fr / 7mm to obtain better artery passage performance and motor performance. At the same time, since the cardiac assist device needs to cross the aortic arch 25 to enter the left ventricle 24 when implanted via the femoral artery, the length of the drive motor 18 should not be too long, and the length-to-diameter ratio of the drive motor 18 is preferably 2 to 4:1.

[0053] Those skilled in the art should understand that since the length of the drive motor 18 is not only the axial length of the housing 1, but also includes the axial length of the front cover 7, the rear cover 8 and the tail cover 9, the length-to-diameter ratio of the drive motor 18 mentioned above refers to the ratio of the overall length of the drive motor 18 to the outer diameter of the housing 1.

[0054] Preferably, since the housing 1 will be in direct contact with human blood and some tissues, in order to ensure that the drive motor 18 can operate stably in the human body, stainless steel that meets the requirements of biocompatibility is used as the housing 1. On the one hand, this avoids the housing 1 from being corroded by blood, which would damage the drive motor 18; on the other hand, it can reduce the irritation of the drive motor 18 and avoid the heart from having an inflammatory or allergic reaction to the drive motor 18.

[0055] Those skilled in the art should understand that the stainless steel housing 1 described above is only a preferred example, and other metal materials that meet medical implant-grade requirements and have been verified by the medical industry can also be used to ensure the biocompatibility of the drive motor 18.

[0056] Preferably, the front cover 7 located at the front end of the housing 1, the rear cover 8 located at the rear end of the housing 1, and the tail cover 9 are all made of materials that meet biocompatibility requirements; alternatively, the materials of the front cover 7, the rear cover 8, and the tail cover 9 can be the same as those of the housing 1, or they can be different materials.

[0057] Preferably, the front cover 7 is located at the front end of the housing 1, and the rotating shaft 5 passes through the central through hole of the front cover 7; the rear cover 8 is located at the rear end of the housing 1; one side of the tail cover 9 is sealed to the rear cover 8, and the other side of the tail cover 9 is connected to the conduit 15; preferably, both the front cover 7 and the rear cover 8 are fitted with the housing 1, one side of the tail cover 9 is fitted with the rear cover 8, and the other side of the tail cover 9 is fitted with the conduit 15.

[0058] Because brushed motors have high friction and losses, and generate a lot of heat during operation, potentially producing sparks, in a preferred embodiment, the drive motor 18 adopts a brushless DC permanent magnet motor structure. Since brushless DC motors have no carbon brushes, their structure is simple and reliable, avoiding motor failures caused by carbon brush damage, a common problem in brushed motors. Simultaneously, it also avoids the problem of iron filings generated during the operation of brushed motor carbon brushes. Those skilled in the art should understand that if iron filings enter the human body, they pose a significant safety risk to the patient.

[0059] like Figure 1 Preferably, the stator core 2, hollow cup-shaped winding 3, rotor 4 and shaft 5 are arranged coaxially from the outside to the inside inside the housing 1.

[0060] Because the tooth structure of a brushless DC motor generates cogging torque, the motor speed is unstable and it is difficult to achieve smooth motion. Therefore, in a preferred embodiment, the stator core 2 is a toothless core, which is fixed to the inner wall of the housing 1 in a hollow cylindrical shape to eliminate the cogging torque and make the motor have very smooth operation characteristics. Correspondingly, the winding is set as a hollow cup-shaped winding 3, which can not only improve the stability of motor operation, but also improve the space utilization of the stator side of the drive motor 18.

[0061] Preferably, the stator core 2 comprises an iron-based amorphous alloy as the core material. This iron-based amorphous alloy has an ultrafine grain structure composed of 80% Fe and 20% SiB-type metallic elements, exhibiting high saturation magnetic induction (1.56T) and superior magnetic permeability compared to conventional silicon steel. Furthermore, its permeability remains almost unchanged with increasing frequency. Simultaneously, due to the short-range order and long-range disorder of atomic arrangement, the iron-based amorphous alloy lacks the magnetocrystalline anisotropy caused by directional atomic arrangement, thus exhibiting low loss characteristics. For the same volume, the iron loss of the stator core 2 made of iron-based amorphous alloy is 70%-80% lower than that of silicon steel sheets. Especially with increasing frequency, the low magnetic loss advantage of the iron-based amorphous alloy compared to silicon steel becomes more pronounced. Therefore, applying this material to the core of the drive motor 18 can significantly reduce energy loss and noise, and help the drive motor 18 achieve high-speed, high-frequency rotation. In tests of two prototypes, the surface temperature of the motor made of amorphous alloy material can be reduced by more than 3°C.

[0062] like Figure 2 Preferably, the hollow cup-shaped winding 3 is configured as a copper cup structure, which is woven from hot-melt self-adhesive enameled wire with a certain wire diameter, a certain number of turns, and a certain winding method, and is fixed to the inner side of the stator core 2 with epoxy resin. Under the same spatial dimensions, the cup-shaped winding can increase the number of windings and improve the motor performance, thus further reducing the size of the drive motor 18 and making it more compatible with the core structure.

[0063] Those skilled in the art should understand that the terminal resistance and number of turns of the hollow cup-shaped winding 3 affect the starting current, output torque, and speed constant of the drive motor 18; cup-shaped windings wound with different winding methods have different effective magnetic line cutting lengths, and the longer the effective magnetic line cutting length, the better the winding performance; under the condition that the effective magnetic line cutting length and the number of turns are the same, the shorter the wire length of the winding coil, the smaller the internal resistance, the smaller the copper loss, and the better the winding performance; under the condition that the effective magnetic line cutting length and the number of turns are the same, the thinner the end size of the winding and the smaller the air gap, the better the winding performance.

[0064] Since different patients require different power when using cardiac assist devices, and the specific parameters of the hollow cup-shaped winding 3 can be designed according to actual needs due to the size limitations of the drive motor 18, they will not be elaborated here.

[0065] like Figure 3 In a preferred embodiment, an epoxy resin nano-coating 6 is provided on the inner wall of the stator core 2 for electrical isolation between the stator core 2 and the hollow cup winding 3. Traditional stator core 2 insulation typically employs impregnated varnish and insulating paper, resulting in uneven insulation layer thickness and large space occupation, which is unsuitable for micro-motor applications. The nano-coating process, however, uses high-temperature heating to deposit epoxy resin in gaseous form onto the core surface, thereby polymerizing into a nano-coating. Compared to impregnated varnish and insulating paper, the epoxy resin nano-coating 6 provides uniform coverage, good density, and a coating thickness reduced by more than 60% compared to traditional insulating media, while also meeting regulatory and industry standards for insulation performance.

[0066] Furthermore, since the stator core 2 made of iron-based amorphous alloy may have insufficient saturation magnetic induction, it is necessary to increase the volume of the stator core 2 and / or windings to reduce the magnetic flux density and DC resistance. However, the epoxy resin nano-coating 6, due to its small thickness, can save more space, ensuring that the volume of the drive motor 18 itself does not increase while increasing the volume of the stator core 2 and / or windings. The rotor 4 is a cylindrical shape with a central through-hole, coaxially inserted into the hollow cup-shaped winding 3. The rotating shaft 5 passes through and is fixed in the rotor 4, with both ends of the rotating shaft 5 protruding from both ends of the rotor 4.

[0067] Optionally, ferrite is used as the permanent magnet material of rotor 4; preferably, neodymium iron boron (NdFeB) material is used to make the magnetic poles of rotor 4, which can provide more magnetic energy than ferrite. Under the same volume, the magnetic energy of neodymium iron boron material can reach more than 10 times that of ferrite material, which greatly improves the power density of axial flow pump drive motor 18.

[0068] Preferably, the front and rear ends of the rotating shaft 5 are respectively inserted into the front bearing 10 and the rear bearing 11, and the front bearing 10 and the rear bearing 11 serve as support members for the rotating shaft 5 to support its rotation; the front cover 7 and the rear cover 8 are both provided with bearing chambers on their inner sides, the front bearing 10 and the bearing chamber of the front cover 7 are overfitted, and the rear bearing 11 and the bearing chamber of the rear cover 8 are overfitted, so as to improve rotational stability and prevent the outer ring from sliding at high speed.

[0069] Preferably, the front bearing 10 and the rear bearing 11 are the same size and are both open metal ball bearings.

[0070] Since the cardiac assist device operates in the blood environment for a long time, in order to prevent blood from entering the drive motor 18 and blocking its operation, in a preferred embodiment, a sealing component is provided between the front cover 7 and the rotating shaft 5, and the sealing component slides in cooperation with the rotating shaft 5.

[0071] like Figure 4 , Figure 5 Preferably, the sealing assembly includes a fluororubber sealing ring 12. Fluororubber material has good elasticity and wear resistance, which can ensure low frictional resistance when the shaft 5 rotates and ensure long-term operational reliability. Preferably, in order to overcome the problem of poor coaxiality caused by the softness of fluororubber material, the fluororubber sealing ring 12 is fixed to the front end cover 7 by a steel ring 13 on the outside. Optionally, the fluororubber sealing ring 12 and the outer steel ring 13 are integrally injection molded or stacked and fixed together. The outer steel ring 13 ensures assembly accuracy and coaxiality and reduces form and position tolerances.

[0072] like Figure 4 In a preferred embodiment, the cross-section of the fluororubber sealing ring 12 is approximately stepped, and the steel ring 13 is fixed only on the outer side of the outer step, while the steel ring 13 is not provided on the outer side of the inner step, so as to prevent the sealing assembly from being over-positioned due to too many positioning points, which would make the sealing assembly difficult to install during production.

[0073] refer to Figure 6 In a preferred embodiment, the steel ring 13 is fixed to the outer side of the outer step of the fluororubber sealing ring 12, and the steel ring 13 and the outer step of the fluororubber sealing ring 12 are not of equal width. Instead, the width of the steel ring 13 is slightly smaller than the width of the fluororubber sealing ring 12, so that the front and rear sides of the outer step of the fluororubber sealing ring 12 can protrude outward from the steel ring 13, further increasing the sealing performance of the entire sealing assembly.

[0074] refer to Figure 7 Preferably, a PCB board 14 is provided on the outer side of the rear end cover 8, and a three-phase lead wire 16 is provided at the rear end of the hollow cup-shaped winding 3. The three-phase lead wire 16 passes through the rear end cover 8 and is connected to one side of the PCB board 14. The other side of the PCB board 14 is connected to the three-phase cable 17. Specifically, the tail cover 9 covers the PCB board 14, the three-phase cable 17 and the rear end cover 8. The three-phase cable 17 is led out from the tail cover 9 and placed in the conduit 15 and connected to the control side.

[0075] Preferably, to ensure the safety and reliability of the connection of the three-phase cable 17, the cable lead-out end of the PCB board 14 is fixed by epoxy resin potting inside the tail cover 9.

[0076] In this embodiment, the drive motor 18 uses an iron-based amorphous alloy as the stator core 2 and a nano-coating as the insulating medium, so that its maximum load speed can reach more than 40,000 rpm and the continuous running time exceeds 6 hours. Due to the use of high magnetic permeability materials, the residual magnetism on the surface of the drive motor 18 can be controlled at (15-25) mT. This device meets the system design requirements and safety requirements.

[0077] Example 2

[0078] refer to Figure 8-10 This embodiment provides a cardiac assist device, including a drive motor 18 as described in Embodiment 1, and the features already included in the above embodiments are naturally inherited in this embodiment.

[0079] In a preferred embodiment, the cardiac assist device is an axial flow pump; preferably, the cardiac assist system includes a drive motor 18, an impeller 19, a pig tail tube 21, and an insertion cannula 20. The shaft 5 of the drive motor 18 is connected to the impeller 19 to drive it to rotate, replacing the heart's pumping function; the insertion cannula 20 is disposed on the outer periphery of the impeller 19, with one end of the insertion cannula 20 near the drive motor being an outflow chamber 23 and the other end being an inflow chamber 22. The inflow chamber 22 is connected to the pig tail tube 21. When the cardiac assist device is implanted in the heart, the pig tail tube 21 is located in the left ventricle 24.

[0080] Those skilled in the art should understand that, given that different manufacturers have different designs for the structure of axial flow pumps, components such as impeller 19, pig tail tube 21, and intubation tube 20 can be selected from any design in the prior art. The inventive point of this embodiment is to apply the above-mentioned drive motor 18 to cardiac assist devices such as axial flow pumps, so the specific structure of the axial flow pump will not be described in detail.

[0081] In this embodiment, since the cardiac assist device uses the drive motor 18 as described in Embodiment 1, the entire device is not only more compact and stable in structure, but also has higher output power and longer operating time.

[0082] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A drive motor for a cardiac assist device, characterized in that, include: Casing, stator, rotor and shaft; The housing is cylindrical, and the diameter of the housing is smaller than the inner diameter of the femoral artery or aorta; The stator is a hollow cylindrical shape and is coaxially disposed on the inner wall of the housing. The stator includes a stator core with a toothless structure and a hollow cup-shaped winding. The hollow cup-shaped winding includes a copper cup structure wound with hot-melt self-adhesive enameled wire. The stator core includes an iron-based amorphous alloy core. The inner wall of the iron-based amorphous alloy core is coated with an epoxy resin coating by a nano-coating process. The epoxy resin coating is used to provide electrical isolation and volume compensation for the iron-based amorphous alloy core. The rotor is a cylindrical shape with a central through-hole, and the rotor is coaxially inserted into the stator; The rotating shaft is inserted into and fixed in the rotor, with both ends of the rotating shaft extending out from both ends of the rotor.

2. The drive motor according to claim 1, characterized in that, It also includes a front cover, a rear cover, a support component, and a sealing assembly; The front cover is located at the front end of the housing, and the pivot protrudes from the center of the front cover; the rear cover is located at the rear end of the housing. The sealing component is disposed between the front end cover and the rotating shaft, and the sealing component is slidably engaged with the rotating shaft; The support includes a front bearing and a rear bearing, which are respectively disposed inside the front cover and the rear cover. The two ends of the rotating shaft pass through the front bearing and the rear bearing, respectively.

3. The drive motor according to claim 2, characterized in that, A PCB board is provided on the outer side of the rear end cover. A three-phase lead wire is provided at the rear end of the winding. The three-phase lead wire passes through the rear end cover and is connected to one side of the PCB board. A three-phase cable is connected to the other side of the PCB board.

4. The drive motor according to claim 3, characterized in that, The outer side of the rear end cover is also provided with a tail cover, which covers the PCB board, the three-phase cable and the rear end cover; one side of the tail cover is sealed to the rear end cover, and the other side of the tail cover is connected to a conduit, and the three-phase cable is led out from the tail cover and placed in the conduit.

5. The drive motor according to claim 4, characterized in that, The front cover and the rear cover are both overfitted to the housing; the tail cover is overfitted to the rear cover.

6. The drive motor according to claim 1, characterized in that, The length-to-diameter ratio of the drive motor is 2 to 4:1; the diameter of the drive motor is not greater than 21Fr.

7. The drive motor according to claim 1, characterized in that, The hollow cup-shaped winding is fixed to the inside of the stator with epoxy resin.

8. The drive motor according to claim 1, characterized in that, The rotor includes a neodymium iron boron magnetic pole rotor.

9. The drive motor according to claim 2, characterized in that, Both the front end cover and the rear end cover have bearing chambers on their inner sides. The front end bearing is overfitted to the bearing chamber of the front end cover, and the rear end bearing is overfitted to the bearing chamber of the rear end cover. The front bearing and the rear bearing are the same size, and both are open-type metal ball bearings.

10. The drive motor according to claim 2, characterized in that, The sealing assembly includes an inner ring seal and an outer ring retainer. The inner ring seal includes a fluororubber sealing ring that overfits with the rotating shaft, and the outer ring retainer includes a steel ring that overfits with the front end cover. The inner ring seal and the outer ring retainer are coaxially arranged.

11. A cardiac assist device, characterized in that, Including the drive motor as described in any one of claims 1-10, further comprising: - Impeller, the impeller being connected to the drive motor; - Insertion tube, the insertion tube is disposed on the outer periphery of the impeller, one end of the insertion tube near the drive motor is the outflow chamber, and the other end is the inflow chamber; - Pig tail tube, which is connected to the inflow chamber.

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