Driving device and pumping assembly thereof

Abstract

The driving device and the pumping assembly are small in size and large in torque, the driving device comprises a stator assembly and a rotor assembly which are coaxially arranged, the stator assembly comprises a magnetic conductive sleeve and a hollow cup coil arranged in the magnetic conductive sleeve, and a near end cover and a far end cover are arranged at the two ends of the magnetic conductive sleeve respectively. The magnetic conductive sleeve, the near end cover and the far end cover jointly form a shell, and the magnetic conductive sleeve is of a cylinder structure integrally cast and formed by ferrite alloy materials. The cylindrical tubular magnetic conductive sleeve is processed and formed, the strength is high, the corrosion resistance is good, and the magnetic permeability is high, so that the thickness can be set to be very thin, the outer diameter of the driving device is reduced while the inner diameter is increased, a magnet with a larger diameter can be arranged, the torque of the whole driving device is improved, and the blood pumping flow is improved. And meanwhile, the outer wall of the magnetic sleeve is smooth, and aluminum oxide on the surface of the magnetic sleeve is a poor electric conductor, so that iron crystals are mutually insulated to prevent blood from entering, the surface of the magnetic sleeve does not need to be coated with a coating, and the processing technology is simplified.

Description

TECHNICAL FIELD

[0001] The utility model relates to medical instrument technical field, concretely relates to a drive device and pump assembly thereof. BACKGROUND

[0002] The catheter pump can be introduced into the heart percutaneously and can be configured to assist or replace the natural heart pump function by circulating or continuous pumping of blood to provide blood flow power support for cardiogenic shock and acute heart failure. The catheter pump generally includes a motor, the proximal end of the motor is connected to a catheter, and the distal end of the motor is connected to an impeller. The motor drives the impeller to rotate, thereby pumping the blood in the heart chamber from the blood flowing into the cage to the sleeve, and from the blood flowing out of the cage from the proximal end of the sleeve into the artery. Therefore, in normal use, the motor also enters the heart chamber through the blood vessel, and the outer diameter of the motor is limited by the inner diameter of the blood vessel (usually about 7mm), so the geometric size is small. In order to meet the physiological needs of the human body, the blood flow rate pumped by the catheter pump must meet the requirements, which means that the motor must have high rotor speed and large torque under the premise of small geometric size. At the same time, since the catheter pump needs to be inserted from the blood vessel, considering its bending performance, the length of the continuous rigid structure also cannot be too long. Therefore, how to balance the above-mentioned multiple problems is a big problem in designing the motor. SUMMARY

[0003] The utility model aims at providing a drive device which is small in size and large in torque.

[0004] In order to achieve the above-mentioned purpose, the utility model adopts the technical scheme of a drive device, which comprises a stator assembly and a rotor assembly arranged coaxially. The stator assembly comprises a magnetic conducting sleeve and a hollow cup coil arranged inside the magnetic conducting sleeve. The two ends of the magnetic conducting sleeve are respectively provided with a proximal end cover and a distal end cover. The magnetic conducting sleeve, the proximal end cover and the distal end cover jointly constitute a shell. The magnetic conducting sleeve is a cylindrical structure integrally cast from ferrite alloy material.

[0005] The outer wall of the two ends of the magnetic conducting sleeve is provided with a stepped portion. The proximal end cover and the distal end cover are respectively sleeved on the stepped portion and are welded and fixed.

[0006] The rotor assembly comprises a rotating shaft and a magnet. The proximal end cover and the distal end cover are respectively provided with a proximal end bearing and a distal end bearing. The rotating shaft is axially limited and circumferentially rotates with the proximal end bearing and the distal end bearing. The distal end of the rotating shaft protrudes to the outside of the distal end cover.

[0007] The wall thickness of the magnetic conducting sleeve is less than or equal to 0.3mm.

[0008] The relative magnetic permeability of the magnetic conducting sleeve is greater than or equal to 99.8%.

[0009] The hollow cup coil is fixed by epoxy resin and the magnetic conducting sleeve. The hollow cup coil is embedded in the inside of the epoxy resin.

[0010] The utility model discloses another purpose is to provide a small size, high flow's pumping assembly.

[0011] In order to realize above-mentioned purpose, the utility model discloses a technical scheme for a pumping assembly, the distal end of the rotating shaft is fixedly connected with the impeller, the outer periphery cover of the impeller is equipped with the blood cage, and the outer diameter of the blood cage is equal to the outer diameter of the driving device, and the blood cage is welded and fixed with the distal end cover.

[0012] The blood cage is in the shape of a circular tube as a whole, a plurality of flow windows are formed in the circumferential direction of the circular tube, the flow windows extend from the middle section of the circular tube to the proximal end, two adjacent flow windows are separated by a support, a recess corresponding to the support is formed on the outer wall of the distal end cover, and the proximal end of the support is clamped in the recess and welded and fixed.

[0013] The axial length of the pumping assembly is 30-35 mm, and the diameter is less than 6 mm.

[0014] In the above scheme, the magnetically conductive sleeve is formed in the shape of a cylindrical tube, has high strength, good corrosion resistance and high magnetic permeability, and thus the thickness thereof can be set very thin. When the outer diameter of the driving device is reduced and the inner diameter is increased, a larger diameter magnet can be arranged, thereby improving the torque of the entire driving device and the blood flow rate. Since the magnetically conductive sleeve is an integral cylindrical structure formed by casting, on the one hand, the outer wall thereof does not have a groove-shaped structure like the outer wall of a common silicon steel sheet, and the surface is smooth, and on the other hand, the aluminum oxide on the surface of the magnetically conductive sleeve is a poor electrical conductor, so the iron crystals are insulated from each other to prevent blood from entering, and thus the surface of the magnetically conductive sleeve does not need to be coated with a coating, thereby simplifying the processing technology. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a perspective view of the pumping assembly;

[0016] Figure 2 It is a front view of the pumping assembly;

[0017] Figure 3 It is Figure 2 It is a sectional view along A-A;

[0018] Figure 4 It is Figure 1 It is a structural schematic view after removing the blood cage. DETAILED DESCRIPTION

[0019] For the convenience of understanding, first, we define the orientation involved in the following text: "proximal end", "proximal side" refer to the side close to the operator / doctor, "distal end", "distal side" refer to the side away from the operator / doctor, i.e. the side close to the heart. Next, we will combine the drawings to make a further detailed discussion of the utility model. Figures 1-4 The utility model makes a further detailed discussion.

[0020] A drive device, the drive device 10 comprises coaxially arranged stator assembly 11 and rotor assembly 12, the stator assembly 11 comprises magnetic sleeve 111 and hollow cup coil 112 arranged on the inside thereof, both ends of the magnetic sleeve 111 are respectively provided with proximal end cover 13 and distal end cover 14, the magnetic sleeve 111, the proximal end cover 13 and the distal end cover 14 jointly constitute a shell, the magnetic sleeve 111 is a cylindrical structure integrally casted by ferrite alloy material.

[0021] The ferrite alloy used here is the scheme disclosed in the applicant's authorized invention patent "Magnetic Sleeve and Its Preparation Method and Application" (authorized announcement number: CN115831516B), the composition of the ferrite alloy is: chromium 15%-18%, silicon 0.5%-4%, nickel 0.2%-0.5%, aluminum 3.5%-5.75%, titanium 0.2%-0.6%, yttrium oxide 0.3%-0.7%, molybdenum 0.2%-0.3%, manganese 0.1%-0.3%, cobalt 0.01%-0.3%, carbon content 0.001%-0.1%, the balance is iron and other unavoidable impurities, the content of the other unavoidable impurities is less than 0.9%. By processing the cylindrical tubular magnetic sleeve 111, the strength is high, the corrosion resistance is good, and the magnetic permeability is high, so the thickness can be set very thin, the outer diameter of the drive device is reduced while the inner diameter is increased, a larger diameter magnet can be set, thereby improving the torque of the entire drive device and improving the blood flow. In addition, since the magnetic sleeve 111 is a one-piece cylindrical structure, on the one hand, its outer wall does not have the slot-like structure of the outer wall of ordinary silicon steel sheets, the surface is smooth, and on the other hand, the aluminum oxide on the surface of the magnetic sleeve 111 is a poor electrical conductor, so the iron crystals are insulated from each other to prevent blood from entering, so the surface of the magnetic sleeve 111 does not need to be coated with a coating, simplifying the processing technology.

[0022] The magnetic sleeve 111 not only serves as a component of the stator assembly, but also forms part of the drive device shell. Compared with the conventional epoxy resin potting scheme for forming a shell, at least the following advantages are achieved:

[0023] (1) Improved assembly efficiency and yield: The epoxy resin potting process is complex, time-consuming and has a low yield, such as incomplete coverage, foreign matter incorporation, pinholes, layering, uneven thickness at both ends, wire leakage and other appearance problems. However, the use of the magnetic sleeve 111 and the proximal end cover 13 and distal end cover 14 welding process improves assembly efficiency and yield.

[0024] (2) Improved structural strength: The structural strength of the epoxy resin potting is not high, and there is a risk of being broken during use. The shell uses a three-section welding process, and the structural strength is much stronger than that of the epoxy resin potting pump body.

[0025] (3) The rigidity length is shortened: due to the three-section welding process of the shell, the rigidity length of the pumping assembly is shortened compared to the size of the epoxy resin filled pump body, which will reduce the difficulty of the pumping assembly passing through the blood vessels and the risk of bleeding during the percutaneous interventional surgery.

[0026] (4) The diameter is reduced: since the outermost layer is not covered with epoxy resin, the diameter will be further reduced, and the passability will be enhanced.

[0027] (5) The flow is improved: the magnetic sleeve 111 made by our company is used, the thickness of the stator assembly is reduced, the outer diameter of the driving device 10 is reduced, and the inner diameter of the hollow cup coil 112 is increased, which can accommodate a larger diameter rotor, thereby improving the load speed, and the flow is improved under the condition that the impeller 20 is reduced (since the pump body outer diameter is reduced, the impeller is also reduced), the flow is improved.

[0028] (6) The temperature rise is reduced: since the thermal conductivity of metal is higher than that of plastic epoxy resin shell, during operation, the blood flow will more effectively carry away the heat generated by the driving device 10, thereby reducing the temperature of the driving device 10 itself.

[0029] In order to be connected and fixed with the proximal end cover 13 and the distal end cover 14, the outer wall of the magnetic sleeve 111 at both ends is provided with a stepped portion, and the proximal end cover 13 and the distal end cover 14 are respectively sleeved on the stepped portion and welded and fixed, the connection is smooth and transitioned, avoiding damage to the blood vessels from the vascular intervention chamber. The proximal end cover 13 and the distal end cover 14 here are made of medical grade 316L stainless steel material, and the three-section structure is convenient for assembly of the whole motor, and the three-section structure can be fixed by welding, the overall strength is high, and the risk of breaking the pumping assembly is eliminated.

[0030] The rotor assembly 12 includes a rotating shaft 121 and a magnet 122, and the proximal end cover 13 and the distal end cover 14 are respectively provided with a proximal end bearing 15 and a distal end bearing 16, and the rotating shaft 121 is axially limited and circumferentially rotates with the proximal end bearing 15 and the distal end bearing 16, and the distal end of the rotating shaft 121 protrudes outside the distal end cover 14. The rotating shaft 121 is used to connect and drive the impeller 20 to rotate synchronously, thereby achieving the purpose of pumping blood.

[0031] Since the whole blood pump is guided to the heart chamber through the blood vessels, the outer diameter of the whole blood pump should be as small as possible, and the magnetic sleeve 111 as a component part of the blood pump should also be as small as possible, and the wall thickness of the magnetic sleeve 111 is ≤0.3mm. Under the premise of providing sufficient strength, the magnetic sleeve 111 with this wall thickness can reduce the outer diameter size and the internal space as much as possible.

[0032] Further, the relative magnetic permeability of the magnetic sleeve 111 is ≥ 99.8%. Since the magnetic sleeve 111 has high density and high magnetic flux density, it can have high relative magnetic permeability while meeting the requirement of small overall thickness. Tests show that the magnetic sleeve applied to the blood pump driving device can meet the requirement of ≥ 99.8% relative magnetic permeability, and even reach 100% relative magnetic permeability, without hysteresis torque phenomenon, smooth operation of the driving device, and extremely low eddy current loss. These beneficial effects cannot be achieved by the silicon steel sheets used in ordinary motors.

[0033] In order to further reduce the diameter of the driving device, the hollow cup coil 112 is fixed by epoxy resin with the magnetic sleeve 111, and the hollow cup coil 112 is embedded in the epoxy resin. The epoxy resin can effectively fill the gap between the components and fix the hollow cup coil 112 and the magnetic sleeve 111 together, improve the overall sealing performance, and enhance the mechanical strength of the driving device. Meanwhile, the epoxy resin also has excellent chemical resistance, heat resistance, and corrosion resistance, which can prevent the blood or corrosive flushing liquid from damaging the blood pump. In addition, the epoxy resin also has good insulation performance, which ensures that the blood pump will not fail due to electrical problems during operation, and ensures the safety of the blood pump.

[0034] A pumping assembly, the distal end of the rotating shaft 121 is fixedly connected with an impeller 20, the outer periphery of the impeller is provided with a blood cage 30, the outer diameter of the blood cage 30 is equal to the outer diameter of the driving device 10, and the blood cage 30 is welded and fixed with the distal end cover 14. The distal end cover 14 and the blood cage 30 are both supported by medical-grade 316L stainless steel material, and can be directly welded between them, with high connection strength.

[0035] Further, the blood cage 30 is in the shape of a circular tube, a plurality of flow windows 31 are arranged on the circular tube in the circumferential direction, the flow windows 31 extend from the middle section of the circular tube to the proximal end, two adjacent flow windows 11 are separated by a support column 32, the outer wall of the distal end cover 14 is provided with a recess 141 corresponding to the support column 32, the proximal end of the support column 32 is clamped in the recess 141 and welded and fixed. This structure is beneficial for welding operation on one hand, and on the other hand, blood can be guided by the surface of the distal end cover 14, the blood flow is more stable, and blood damage is reduced.

[0036] The pumping assembly formed by using this material and structure has an axial length of 30mm-35mm and a diameter of <6mm. Compared with the pumping assembly formed by the epoxy resin pouring process, the rigid axial length is reduced by 5mm-10mm, which greatly improves the bending performance of the pumping assembly and reduces the damage to the blood vessel during the intervention and withdrawal of the blood vessel. More importantly, the shortening of the rigid length does not cause the reduction of the driving device torque and the flow rate, and the driving device can reach 40000rpm, and the blood flow rate of the pumping can reach 6L / min.

[0037] The embodiments described above are only some of the embodiments of the present application, not all the embodiments, the preferred embodiments of the present application are given in the drawings, but do not limit the patent scope of the present application. The present application can be implemented in many different forms, and conversely, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing specific embodiments, or make equivalent replacements to some of the technical features. Any equivalent structure made by using the content of the specification and drawings, directly or indirectly applied to other related technical fields, is also within the scope of the patent protection of the present application.

Claims

1. A drive arrangement, the drive arrangement (10) comprising a stator assembly (11) and a rotor assembly (12) arranged coaxially, characterised in that: The stator assembly (11) comprises a magnetic conducting sleeve (111) and a hollow cup coil (112) arranged inside the magnetic conducting sleeve (111), both ends of the magnetic conducting sleeve (111) are provided with a proximal end cover (13) and a distal end cover (14) respectively, the magnetic conducting sleeve (111), the proximal end cover (13) and the distal end cover (14) jointly constitute a driving device housing, and the magnetic conducting sleeve (111) is a cylindrical structure integrally casted by ferrite alloy material.

2. The drive apparatus according to claim 1, characterized by: The outer wall of both ends of the magnetic conducting sleeve (111) is provided with a stepped portion, the proximal end cover (13) and the distal end cover (14) are respectively sleeved on the stepped portion and welded and fixed, and the joint is smoothly transitioned.

3. The drive apparatus according to claim 1, characterized by: The rotor assembly (12) comprises a rotating shaft (121) and a magnet (122), the proximal end cover (13) and the distal end cover (14) are respectively provided with a proximal end bearing (15) and a distal end bearing (16), the rotating shaft (121) is axially limited and circumferentially rotatably connected with the proximal end bearing (15) and the distal end bearing (16), and the distal end of the rotating shaft (121) protrudes outside the distal end cover (14).

4. The drive apparatus according to claim 1, characterized by: The wall thickness of the magnetic conducting sleeve (111) is less than or equal to 0.3 mm.

5. The drive apparatus according to claim 1, characterized by: The relative magnetic permeability of the magnetic conducting sleeve (111) is greater than or equal to 99.8%.

6. The drive apparatus according to claim 1, characterized by: The hollow cup coil (112) is fixed by epoxy resin and the magnetic conducting sleeve (111), and the hollow cup coil (112) is embedded in the epoxy resin.

7. A pumping assembly comprising the drive device of any one of claims 1-6, characterized by: The distal end of the rotating shaft (121) is fixedly connected with an impeller (20), the outer periphery of the impeller (20) is provided with a blood cage (30), the outer diameter of the blood cage (30) is equal to the outer diameter of the driving device (10), and the blood cage (30) is welded and fixed with the distal end cover (14).

8. The pumping assembly of claim 7, wherein: The blood cage (30) is in the shape of a circular tube as a whole, a plurality of flow windows (31) are arranged in the circumferential direction of the circular tube, the flow windows (31) extend from the middle section of the circular tube to the proximal end, two adjacent flow windows (31) are separated by a support column (32), the outer wall of the distal end cover (14) is provided with a recess (141) corresponding to the support column (32), the proximal end of the support column (32) is clamped in the recess (141) and welded and fixed.

9. The pumping assembly of claim 7, wherein: The axial length of the pumping assembly is 30 mm to 35 mm, and the diameter is less than 6 mm.

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