Interventional axial flow blood pump

Abstract

The utility model discloses an intrusive axial flow blood pump which comprises an impeller mounting cylinder, a stator assembly, an optical fiber type pressure sensor and a tail wrapping and sealing device, the stator assembly comprises a stator shell, a magnetic conducting stator and a stator winding, the stator winding is connected with a power line, a blood outlet is formed in the impeller mounting cylinder, and the optical fiber type pressure sensor is provided with an optical fiber; the tail wrapping and sealing device comprises a right sealing cover, an outer wrapping sleeve, a guide wire and a liquid passing pipe, the right sealing cover comprises an outer cover, an inner cover and a tail cover, the outer surface of the outer cover comprises a revolution surface, a cylindrical surface and a rough surface, the rough surface is fixedly connected with the outer wrapping sleeve in a sleeving mode, and the rough surface and the outer wrapping sleeve are bonded through biocompatible glue; the right end of the tail cover is provided with a through hole and a blind hole, and the outer sleeve wraps the power line, the optical fiber, the liquid passing pipe and the guide wire. The rough surface is arranged on the outer cover to be connected with the outer casing pipe, connection is tight, the outer casing pipe is not prone to falling off, and propelling of the axial flow blood pump in an arterial blood vessel is facilitated through tough supporting of the guide wire.

Description

Technical Field

[0001] The utility model belongs to the field of interventional medical equipment, and more specifically, relates to an interventional axial flow blood pump. Background Art

[0002] As an alternative to heart transplantation, artificial hearts break through the limitation on the number of heart transplant donors. They can not only provide transitional treatment or restore heart function after heart transplantation, but also provide lifelong long-term treatment. Therefore, artificial hearts have been able to develop rapidly and make continuous technological breakthroughs.

[0003] An interventional ventricular assist device (artificial blood pump) is a ventricular assist product for high-risk PCI circulation protection and high-risk PCI surgery for cardiogenic shock. Currently, the American company Abiomed has launched corresponding products (Impella series) around the world. It is small in size and less invasive, and can reduce intraoperative and postoperative complications. Animal experiments, clinical left-stage and clinical application data show that this product has very good effects in directly reducing the load on the left ventricle, pushing the left ventricular blood directly into the aorta, promoting left-direct blood flow and increasing aortic blood pressure, mean arterial pressure and cardiac output, reducing left ventricular end-diastolic volume and end-diastolic pressure, increasing coronary peak flow, and improving myocardial oxygen supply balance.

[0004] The blood pump motor, the core component of the interventional heart pump, is a powerful micro-special motor with small size, high torque, high reliability and excellent biocompatibility. It is usually implanted through femoral artery puncture and pushed into the left ventricle of the heart. It can usually work continuously for 3 to 14 days in the human body. During the operation of the blood pump motor, the inside of the blood pump motor is immersed in high-pressure liquid medium. The coil winding of the blood pump motor must be completely isolated from the erosion of liquid substances under heating conditions to avoid insulation failure and endanger human life. Biocompatible potting glue is usually used to isolate the coil winding from the internal high-pressure liquid to keep the blood pump motor stable and reliable for a long time.

[0005] When the interventional heart pump is working, high-pressure liquid will be injected into the blood pump motor. With the continuous injection of high-pressure liquid, the blood pump motor always maintains a high liquid pressure environment, thereby preventing blood from rushing into the motor. The tail tube of some micro axial flow blood pumps uses locking parts such as locking rings on the blood pump body. During long-term use, blood is easy to remain in the gaps and edges of the locking parts and coagulate, which is difficult to clean. In addition, the tail tube has poor propulsion and support effects on the blood pump body, resulting in inconvenience in the movement of the blood pump body in the blood vessel.

[0006] In addition, the performance of continuous blood flow left ventricular assist devices (artificial blood pumps) has been greatly improved in recent years, and the number of implants has also increased year by year. However, complications caused by implantation often plague postoperative patients and affect their quality of life, and the occurrence of these complications is closely related to poor blood pressure control. For invasive artificial blood pumps with miniaturized structures, how to integrate blood pressure monitoring functions into products has become an important manifestation of the practicality of the product. Interventional artificial blood pumps generally monitor cardiovascular pressure by installing miniature pressure sensors. This data monitoring achieves real-time and accurate control, which is of great significance for the smooth progress of the operation and life support during the postoperative recovery period. Existing invasive artificial blood pumps generally adhere pressure sensors and optical fibers to the outer surface of the axial flow blood pump, and cover and fix them with biocompatible glue. The installation process is not very convenient and causes the surface of the blood pump to bulge locally and occupy space. Utility Model Content

[0007] In response to the above defects or improvement needs of the prior art, the utility model provides an interventional axial flow blood pump, wherein a rough surface is provided on the outer cover to connect the outer sleeve, so that the connection between the outer sleeve and the outer cover is very tight and not easy to fall off, and a guide wire is provided in the outer sleeve. The tough support of the guide wire is conducive to the advancement of the axial flow blood pump in the arterial blood vessel.

[0008] To achieve the above-mentioned purpose, according to the utility model, an interventional axial flow blood pump is provided, comprising an impeller mounting tube, a stator assembly, an optical fiber pressure sensor and a tail wrapping sealing device, wherein the stator assembly comprises a stator shell, a magnetic stator and a stator winding connected in sequence from the outside to the inside, the stator winding is connected to the left end of the power cord, the impeller mounting tube is mounted on the left end of the stator shell, and a blood outlet is provided on the impeller mounting tube, characterized in that:

[0009] The optical fiber pressure sensor is mounted on the stator housing to measure the pressure of blood flowing out of the blood outlet, and the optical fiber pressure sensor has an optical fiber;

[0010] The tail wrapping sealing device includes a right cover, an outer sleeve, a guide wire and a liquid passage tube. The right cover includes an outer cover, an inner cover and a tail cover. The inner cover and the tail cover are both located inside the outer cover. The left ends of the outer cover and the inner cover are respectively sealed and connected to the right end of the stator shell. The right end of the inner cover is fixedly connected to the left end of the tail cover. The outer surface of the outer cover includes a rotating surface, a cylindrical surface and a rough surface in sequence from left to right. The rough surface is formed by roughening a cylindrical curved surface. The outer sleeve is fixedly sleeved on the rough surface and the rough surface The rough surface and the outer sleeve are bonded with biocompatible glue, the outer diameter of the portion of the outer sleeve that is sleeved on the rough surface is consistent with the diameter of the cylindrical surface, the right end of the tail cover is provided with a through hole and a blind hole, the through hole of the tail cover is sealed and connected to the liquid passing tube, the left end of the liquid passing tube extends into the inner cavity of the inner cover, the blind hole of the tail cover is sealed and connected to the left end of the guide wire, the power cord, optical fiber and the right end of the liquid passing tube all pass through the outer cover and enter the outer sleeve, and the outer sleeve wraps the power cord, optical fiber, liquid passing tube and guide wire.

[0011] Preferably, a groove is provided on the outer side wall of the stator shell, the optical fiber pressure sensor is installed in the groove, the optical fiber pressure sensor does not extend beyond the outer side wall of the stator shell, the optical fiber extends along the groove and the right end of the optical fiber extends beyond the right end of the groove;

[0012] The outer cover is provided with a wiring hole so that the optical fiber can extend into the outer cover and then enter the outer casing. The wiring hole is sealed with biocompatible glue.

[0013] Preferably, the groove is covered with biocompatible glue for completely fixing the detection head and optical fiber of the optical fiber pressure sensor, and the biocompatible glue fills and covers the gaps and edges of the groove to prevent residual blood from clotting.

[0014] Preferably, the liquid passage tube is made of biocompatible plastic and has a length of 1.3 meters to 2 meters after being straightened, and the guide wire is made of biocompatible nickel-titanium wire material and has a length of 1.3 meters to 1.8 meters after being straightened.

[0015] Preferably, the right ends of the power cord, optical fiber, liquid passage tube and guide wire do not extend beyond the outer casing.

[0016] Preferably, the optical fiber pressure sensor further comprises a detection head connected to the optical fiber;

[0017] For the groove, the groove depth of the portion for accommodating the detection head is 0.2 mm to 0.4 mm, and the groove depth of the portion for accommodating the optical fiber is 0.06 mm to 0.15 mm.

[0018] Preferably, the rotor assembly of the interventional axial flow blood pump comprises a rotating shaft, a permanent magnet and a rotor sleeve connected in sequence from the inside to the outside, and the stator housing comprises an outer shell and a left cover connected to the left end of the outer shell;

[0019] The interventional axial blood pump further includes a left end bearing, a right end bearing, an impeller and a preload spring, wherein the left end bearing and the right end bearing are both ball bearings, the outer ring of the right end bearing is fixedly mounted on the right cover, and the preload spring is mounted on the rotating shaft;

[0020] The left cover has a horizontal step hole, which is a through hole and includes a first hole, a second hole and a third hole which are arranged in sequence from left to right and whose diameters increase from small to large. The first step of the inner wall of the left cover forms the first hole and the second hole, and the second step of the inner wall of the left cover forms the second hole and the third hole. The left end of the rotating shaft passes through the left cover at the step hole and is connected to the impeller. There is a first gap between the hole wall of the first hole and the rotating shaft, and the first gap serves as an outlet for high-pressure liquid entering the motor housing. The outer ring of the left end bearing is fixedly mounted on the hole wall of the third hole and abuts against the second step. The outer diameter of the inner ring of the left end bearing is smaller than the hole diameter of the second hole. The inner ring of the left end bearing cooperates with the permanent magnet to clamp the preload spring, and the preload spring applies elastic force to the inner ring of the left end bearing.

[0021] There are a second gap and a third gap between the inner ring of the left end bearing and the inner ring of the right end bearing and the rotating shaft respectively, the second gap enables the inner ring of the left end bearing to reciprocate along the axial direction of the rotating shaft under the elastic force of the preload spring and enables the inner ring of the left end bearing and the rotating shaft to still rotate synchronously, the third gap enables the inner ring of the right end bearing and the rotating shaft to still rotate synchronously, and a force transmission member is also fixedly installed on the rotating shaft, and the force transmission member applies force to the right on the inner ring of the right end bearing under the elastic force of the preload spring;

[0022] The impeller mounting tube is fixedly mounted on the left cover and surrounds the impeller. The inner cavity of the impeller mounting tube is communicated with the first gap. The side wall of the impeller mounting tube is provided with the blood outlet at a position corresponding to the impeller.

[0023] Preferably, a chamfer is provided on the first step, thereby forming a bell mouth with a gradually decreasing diameter along the direction from the second hole to the first hole, so that the high-pressure liquid flows from the second hole into the first gap to fill the first gap, thereby reducing the risk of blood backflowing into the stator shell.

[0024] Preferably, the chamfer angle is 20° to 40°, that is, the angle with the center line of the rotating shaft is 20° to 40°.

[0025] Preferably, the first gap is 5 μm to 15 μm, the second gap is 1 μm to 3 μm, and the third gap is 1 μm to 3 μm.

[0026] In general, the above technical solutions conceived by the utility model can achieve the following beneficial effects compared with the prior art:

[0027] 1) The utility model is an interventional axial flow blood pump, the outer cover of which has a cylindrical surface and a rough surface, the inner wall of the outer sleeve cooperates with the rough surface of the outer cover, which is conducive to the outer sleeve tightly holding the rough surface of the outer cover, and then assisted by biocompatible glue bonding, so that the outer sleeve can be firmly and reliably connected to the outer cover, not easy to fall off, and blood is not easy to remain; in addition, during the pushing process of the blood pump, the tough support of the guide wire in the outer sleeve is conducive to the advancement of the axial flow blood pump in the arterial blood vessel.

[0028] 2) The utility model provides an interventional axial flow blood pump, which places a fiber optic pressure sensor by providing a groove on the surface of the stator shell, without adding extra space, thus avoiding the occupation of the internal structure of the blood pump motor and affecting the increase of power output. By providing a fiber optic pressure sensor to monitor blood pressure data in real time, accurate control during and after surgery is achieved.

[0029] 3) In the interventional axial flow blood pump of the utility model, a right sealing cover for fixing the guide wire and the liquid passage tube is provided at the right end (tail) of the stator shell, which can effectively prevent the loosening of the guide wire and the leakage of the liquid passage tube.

[0030] 4) The utility model is an interventional axial flow blood pump, in which the optical fiber of the optical fiber pressure sensor is integrated into the outer casing at the right end (tail) of the stator shell, and is wrapped together with the liquid tube, guide wire and motor power line by the outer casing, so that the integrity of the product is better.

[0031] 5) In the present invention, an interventional axial flow blood pump is provided. The right-end bearing at the entrance of the high-pressure liquid on the stator shell and the left-end bearing at the exit are both ball bearings to cooperate with the rotating shaft. There is a second gap between the inner ring of the left-end bearing and the rotating shaft, but the two are not independently supported and cannot form a completely suspended, non-contact cooperation form. The second gap is mainly to allow the inner ring of the left-end bearing to move axially under the preload force of the preload spring to compensate for the clearance of the left-end bearing. Due to the very small second gap between the two and the cooperation mode of the two non-independent supports, the inner ring of the left-end bearing will rotate synchronously with the rotating shaft (the two are relatively static) and will not produce friction and wear. The right-end bearing is also a ball bearing and there is a third gap between it and the rotating shaft. Like the left-end bearing, the inner rings of the rotating shaft and the right-end bearing are relatively static and will not produce friction and wear. Therefore, the present invention reduces the uncertainty risk caused by changes in friction state conditions by using ball bearings for both the left-end bearing and the right-end bearing and the inner rings have gaps with the rotating shaft, and can prevent the risk of blood components entering the blood pump motor and coagulating.

[0032] 5) The utility model is an interventional axial blood pump. Since there is a second gap between the inner ring of the left end bearing and the rotating shaft, and the preload spring generates a certain elastic force (axial preload force) acting on the inner ring of the left end bearing, under the action of the preload force, the inner ring of the ball bearing can move axially relatively freely, and the outer ring of the left end bearing is subjected to the axial force of the second step in the opposite direction to the corresponding inner ring, so that the inner and outer rings of the left end bearing can be axially displaced from each other, and the rolling elements inside the left end bearing are clamped by the inner and outer rings and pressed against the raceways of the inner and outer rings, and will not generate noise and vibration wear due to slight jumping. Therefore, the design of the preload force of the preload spring and the second gap between the inner ring of the left end bearing and the rotating shaft can timely compensate for the slight clearance caused by the wear of the left end bearing, so that the axial blood pump can maintain a stable operating state during the working process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the utility model;

[0034] Figure 2 It is a schematic diagram of the utility model after a part of the outer casing is cut away;

[0035] Figure 3 It is an exploded schematic diagram of the utility model;

[0036] Figure 4 yes Figure 3 The enlarged schematic diagram of point A in the middle;

[0037] Figure 5 It is a schematic diagram of the utility model after the outer sleeve and the outer cover are separated;

[0038] Figure 6 yes Figure 5 The enlarged schematic diagram of point B in the middle;

[0039] Figure 7 It is a schematic diagram of the outer cover in the utility model;

[0040] Figure 8 It is a partial schematic diagram of the utility model;

[0041] Fig. 9 yes Figure 8 The enlarged schematic diagram of the center C;

[0042] Fig.10 It is a cross-sectional view of the utility model after removing some parts of the tail wrapping sealing device;

[0043] Fig.11 yes Fig.10 The enlarged schematic diagram of point D in the middle;

[0044] Fig.12 It is a schematic diagram of the left cover in the utility model;

[0045] Fig.13 It is a force diagram of the left end bearing in the utility model;

[0046] Figure 14a to Figure 14c It is a schematic diagram of various shapes of preload springs in the utility model. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model. In addition, the technical features involved in each embodiment of the utility model described below can be combined with each other as long as they do not conflict with each other.

[0048] Referring to the accompanying drawings, an interventional axial flow blood pump includes an impeller mounting tube 7, a stator assembly 1, a fiber optic pressure sensor 8 and a tail wrapping sealing device 9, wherein the stator assembly 1 includes a stator shell 11, a magnetic stator and a stator winding which are sequentially connected from the outside to the inside, and the stator winding is connected to the left end of the power cord 114. The impeller mounting tube 7 is installed at the left end of the stator shell 11, and a blood outlet 71 is provided on the impeller mounting tube 7. The fiber optic pressure sensor 8 is installed on the stator shell 11, and a groove 1110 is preferably provided on the outer wall of the stator shell 11.

[0049] The fiber optic pressure sensor 8 is preferably installed in the groove 1110 to measure the pressure of the blood flowing out of the blood outlet 71. The fiber optic pressure sensor 8 as a whole does not extend beyond the outer wall of the stator shell 11, that is, the fiber optic pressure sensor 8 does not protrude relative to the outer wall of the stator shell 11. The fiber optic pressure sensor 8 has an optical fiber 81, which is used to transmit a pressure signal. The optical fiber 81 extends along the groove 1110 and the right end of the optical fiber 81 extends beyond the right end of the groove 1110. The groove 1110 is covered with biocompatible glue to completely fix the detection head 82 and the optical fiber 81 of the fiber optic pressure sensor 8, and the biocompatible glue fills and covers the gaps and edges of the groove 1110 to prevent residual blood from clotting.

[0050] The tail wrapping sealing device 9 includes a right cover 113, a guide wire 91, a liquid passing tube 93 and an outer sleeve 92. The left end of the right cover 113 is sealed and connected to the right end of the stator shell 11. The right end of the right cover 113 is sealed and connected to the outer sleeve 92. The right end of the right cover 113 is provided with a through hole 1134 and a blind hole 1135. The through hole 1134 of the right cover 113 is sealed and connected to the liquid passing tube 93, and the left end of the liquid passing tube 93 extends into the inner cavity of the right cover 113 to pass high-pressure liquid into the stator shell 11. The high-pressure liquid in the liquid passing tube 93 is pumped into the stator shell 11 by a high-pressure pump. The blind hole 1135 of the right cover 113 35 is sealed and connected to the guide wire 91, and the right ends of the power cord 114, optical fiber 81 and liquid tube 93 all pass through the right cover 113 and enter the outer sleeve 92, and the outer sleeve 92 wraps the power cord 114, optical fiber 81, liquid tube 93 and guide wire 91. A wiring hole 1136 is provided on the side wall of the outer cover 1133, so that the optical fiber 81 can enter the outer sleeve 92 after extending into the right cover 113. After the optical fiber 81 extends into the outer cover 1133 from the wiring hole 1136, it does not pass through the inner cover 1131 and the tail cover 1132 outside the inner cover 1131 and the tail cover 1132, but directly passes through the outer cover 1133 and enters the outer sleeve 92. The right end of the groove 1110 extends along the axial direction of the stator shell 11 to the right end surface of the stator shell 11, and a notch is formed on the right end surface of the stator shell 11, so that the optical fiber 81 can be bent and extend into the right cover 113 from the wiring hole 1136. The wiring hole 1136 is sealed with biocompatible glue. The right ends of the power cord 114, the optical fiber 81, the liquid tube 93 and the guide wire 91 do not extend beyond the outer casing 92, that is, they are all wrapped in the outer casing 92.

[0051] The right cover 113 includes an outer cover 1133, an inner cover 1131 and a tail cover 1132. The left end of the inner cover 1131 is fixedly connected to the right end of the outer shell 111. The left end of the tail cover 1132 is fixedly connected to the right end of the inner cover 1131. The right end of the tail cover 1132 is provided with the through hole 1134 and the blind hole 1135. The through hole 1134 of the tail cover 1132 is clamped with the liquid pipe 93. The left end of the liquid pipe 93 extends into the inner cavity of the tail cover 1132. The left end of the guide wire 91 is clamped into the blind hole 1135 of the tail cover 1132. The left end of the outer cover 1133 is fixedly connected to the right end of the outer shell 111, and the inner cover 1131 and the tail cover 1132 are both located in the outer cover 1133. The power line 114, the optical fiber 81 and the liquid-passing tube 93 all pass through the outer cover 1133, and the right end of the outer cover 1133 is sealed and connected to the outer sleeve 92. The right cover 113 is divided into multiple structures of the outer cover 1133, the inner cover 1131 and the tail cover 1132, which are convenient for connection with the stator housing 11 and for threading. The tail cover 1132 is mainly used to install the liquid-passing tube 93 and the guide wire 91, the outer cover 1133 is mainly used to install the outer sleeve 92, and the right end bearing 4 can be installed inside the inner cover 1131 to support the rotor assembly 2. After the optical fiber 81 extends into the outer cover 1133 from the wiring hole 1136, it does not pass through the inner cover 1131 and the tail cover 1132 outside the inner cover 1131 and the tail cover 1132, but directly passes through the outer cover 1133 and enters the outer sleeve 92.

[0052] The outer side wall of the outer cover 1133 has a revolving surface 1137, a cylindrical surface 1138 and a rough surface 1139 connected together from left to right in sequence. The rough surface 1139 is formed by a cylindrical curved surface preferably roughened by knurling or laser, and is used to sleeve the outer sleeve 92. The outer sleeve 92 is made of biocompatible plastic and has a certain toughness. The inner circular surface of the outer sleeve 92 cooperates with the rough surface 1139 of the outer cover 1133. The diameter of the inner circular surface of the outer sleeve 92 is slightly smaller than the diameter of the rough surface 1139 of the outer cover 1133. This design is conducive to the outer sleeve 92 tightly hugging the rough surface 1139 of the outer cover 1133, and the two are bonded with biocompatible glue to enable them to be reliably connected. The outer diameter of the portion of the outer sleeve 92 sleeved on the rough surface is consistent with the diameter of the cylindrical surface 1138, and the outer wall of the portion of the outer sleeve 92 sleeved on the rough surface is in contact with the cylindrical surface 1138. The design of the outer sleeve 92 ensures that the outer diameter of the outer sleeve 92 installed in place is consistent with the diameter of the cylindrical surface of the outer cover 1133, and the end surface of the outer sleeve 92 is flat, thereby forming a smooth transition state to prevent blood from remaining and coagulating in tiny corners and gaps.

[0053] The rotor assembly 2 of the interventional axial flow blood pump includes a rotating shaft 21 , a permanent magnet 22 and a rotor sleeve 23 which are sequentially connected from the inside to the outside. The stator housing 11 includes an outer shell 111 and a left cover 112 connected to the left end of the outer shell 111 .

[0054] The interventional axial blood pump further includes a left end bearing 3, a right end bearing 4, an impeller 5 and a preload spring 6. The left end bearing 3 and the right end bearing 4 are both ball bearings, preferably deep groove ball bearings with pure radial force. The outer ring of the right end bearing 4 is fixedly mounted on the right cover 113, the preload spring 6 is installed on the rotating shaft 21, and the outer ring of the right end bearing 4 is preferably mounted on the inner cover 1131. The inner cover 1131 is provided with a limiting boss, and the tail cover 1132 presses the outer ring of the right end bearing 4 on the limiting boss.

[0055] The left cover 112 has a horizontal step hole 114, which is a through hole and includes a first hole 1141, a second hole 1142 and a third hole 1143 which are arranged from left to right and whose diameters are from small to large, that is, the aperture of the first hole 1141 is smaller than the aperture of the second hole 1142 and smaller than the aperture of the third hole 1143, and the first hole 1141 and the third hole 1143 are directly connected to the external environment of the left cover 112, and the first step 115 on the inner wall of the left cover 112 forms the first hole 1141 and the second hole 1142. The second step 116 of the inner wall of the cover 112 forms the second hole 1142 and the third hole 1143. The left end of the rotating shaft 21 passes through the left cover 112 from the step hole 114 and is connected to the impeller 5. There is a first gap 1144 between the hole wall of the first hole 1141 and the rotating shaft 21, that is, the gap between the two is matched. The first gap 1144 serves as an outlet (overflow port) for the high-pressure liquid in the stator housing 11. The high-pressure liquid in the stator housing 11 is pumped into the high-pressure pump inside and outside, so as to prevent the blood outside the stator housing 11 from flowing back into the blood pump. The outer ring of the left end bearing 3 is fixedly mounted on the hole wall of the third hole 1143 and abuts against the second step 116. The outer diameter of the inner ring of the left end bearing 3 is smaller than the hole diameter of the second hole 1142, so that the high-pressure liquid in the stator case 11 flows out of the left end bearing 3 and enters the second hole 1142 to prevent the inner ring of the left end bearing 3 from scratching the second step 116 during rotation. The high-pressure liquid then flows out of the left cover 112 through the first gap 1144 connected to the second hole 1142. There is a second gap between the inner ring of the left end bearing 3 and the rotating shaft 21. The inner ring of the left end bearing 3 cooperates with the permanent magnet 22 to clamp the preload spring 6, and the preload spring 6 applies elastic force (preload force) on the inner ring of the left end bearing 3. The second gap 1145 allows the inner ring of the left end bearing 3 to reciprocate along the axial direction of the rotating shaft 21 under the elastic force of the preload spring 6 and allows the inner ring of the left end bearing 3 to still rotate synchronously with the rotating shaft 21. A force transmission member 26 is also fixedly mounted on the rotating shaft 21. The force transmission member 26 applies force to the right on the inner ring of the right end bearing 4 under the elastic force of the preload spring 6. The force transmission member 26 can be a spring member (the spring member is clamped by the permanent magnet 22 and the inner ring of the right end bearing 4), or a sleeve made of biocompatible plastic.

[0056] There is a third gap between the inner ring of the right end bearing 4 and the rotating shaft 21, and the third gap allows the inner ring of the right end bearing 4 and the rotating shaft 21 to still rotate synchronously. Therefore, the second gap and the third gap are very small, and the line contact between the inner ring of the left end bearing 3 and the inner ring of the right end bearing 4 and the rotating shaft 21 is greater than the point contact friction between the ball and the raceway, so the ball has priority to produce relative motion. The matching clearance between the rotating shaft 21 and the inner ring is very small. From a microscopic level, there is still molecular adsorption (and the viscosity of water molecules in high-pressure liquid), which will also prevent the inner ring and the rotating shaft 21 from relative rotation, so the inner ring and the rotating shaft 21 rotate synchronously, and there is almost no circumferential wear on the rotating shaft 21 and the inner ring of the bearing.

[0057] Like the left bearing 3, there is a gap between the right bearing 4 and the rotating shaft 21. The left bearing 3 and the right bearing 4 do not need to adopt a transition or interference fit, which will cause assembly troubles, and the rotating shaft 21 is prone to bending under force, and the fit is prone to produce debris that is difficult to clean.

[0058] In fact, when ball bearings are used, friction only exists between the rolling element and the raceway. Taking ball bearings as an example, the ball and the raceway are in point contact and rolling friction, so the wear is very small. Because the size of the axial flow motor of the axial flow blood pump of the present invention is very small, it is basically unlikely to use roller bearings or needle bearings in actual situations, because the contact between rollers and needles is line contact, and compared with the point contact of the ball of the ball bearing, the contact area between the rollers and needles and the raceway is large, and the friction will be a little larger, which is easy to cause relative rotation between the inner ring of the bearing and the rotating shaft 21, thereby aggravating the wear.

[0059] In addition, since there are gaps between the rotating shaft 21 and the inner rings of the left end bearing 3 and the right end bearing 4, the rotating shaft 21 may produce axial movement. If there is axial movement, it means that there is an external force, and the preload force of the preload spring 6 needs to resist this external force. As long as the preload force is slightly larger than the external force, the rotor assembly 2 is stable as a whole. This external force is mainly the force of blood (fluid) on the impeller 5 (because the stator shell 11 is full of high-pressure liquid, the flow rate of high-pressure liquid is actually very small, and the disturbance of high-pressure liquid is basically negligible). After the impeller 5 rotates, it will form a force that pulls the rotor assembly 2 to the left, but this force fluctuates within a certain range under the disturbance of blood. The preload force of the preload spring 6 can offset the fluctuation of the force of blood (fluid) on the impeller 5, and prevent the rotating shaft 21 from moving along its own axial direction. In addition, the axial sliding of the rotating shaft 21 relative to the inner rings of the left-end bearing 3 and the right-end bearing 4 takes up very little time in the entire life cycle. Only when the ball bearing produces a small clearance due to its own wear will the inner ring have a small axial movement, so there is almost no axial wear.

[0060] The impeller mounting tube 7 is fixedly mounted on the left cover 112 and surrounds the impeller 5 . The inner cavity of the impeller mounting tube 7 is connected to the first gap 1144 . The side wall of the impeller mounting tube 7 is provided with the blood outlet 71 at a position corresponding to the impeller 5 .

[0061] The rotating shaft 21 of the utility model is supported by two ball bearings on the left and right sides. The rolling friction of the ball bearings is significantly lower than that of the existing sliding bearings, which reduces the generation of wear particles. The rotor assembly 2 and the impeller 5 thereon can maintain a stable operating state for a long time. The high-pressure liquid inside the motor flows in the gap between the inner and outer rings of the ball bearings, passes through the inside of the right end bearing 4, the gap between the stator assembly 1 and the rotor assembly 2, and the inside of the left end bearing 3 in turn, and then enters the first gap 1144 between the left end bearing 3 and the left cover 112, and then flows out of the micro motor from the first gap 1144 (radial gap, size 5μm ~ 15μm), enters the space formed by the impeller 5 and the left cover 112 (spacing 0.03mm ~ 0.15mm), and continuously flows out from the blood outlet 71 into the human blood. The chamfer 1151 of the edge of the first step 115 is α and α=20°~40°, so that a gradually decreasing diameter trumpet is formed along the direction from the second hole 1142 to the first hole 1141, so that the high-pressure liquid flows from the second hole 1142 into the first gap 1144 to fill the first gap 1144, which is conducive to the high-pressure liquid filling the first gap 1144 and reducing the risk of blood backflow. Due to the continuous injection of high-pressure liquid, the liquid pressure inside the stator housing 11, the first gap 1144, and the space between the impeller 5 and the left cover 112 can be greater than the nearby blood pressure, and blood components will not enter these areas to cause coagulation blockage. The material of the left cover 112 is a biocompatible metal (stainless steel or titanium alloy).

[0062] Since the preload spring 6 is mounted on the rotating shaft 21, one end of the preload spring 6 abuts against the inner ring of the left end bearing 3, and the other end presses on the left rotor potting glue 24. After the preload spring 6 is installed, it is in a compressed state, that is, the preload spring 6 can generate a certain elastic force (axial preload force, F 1 The axial force F (0.1N~1N) acts on the inner ring of the left end bearing 3, while the outer ring of the left end bearing 3 bears the axial force F opposite to the corresponding inner ring. 2, so that the inner and outer rings of the left end bearing 3 are mutually displaced along the axial direction, and the balls are therefore tightly attached to the inner and outer ring raceways, and will not generate noise and vibration wear due to slight jumping. Obviously, although the wear amount inside the ball bearing itself is small, for long-life service conditions, it is necessary to consider the increase in bearing clearance caused by the accumulation of wear. In order to keep the axial blood pump in a stable operating state during operation, under the action of the preload, the inner ring of the left end bearing 3 needs to move relatively freely along the axial direction to timely compensate for the slight clearance caused by the wear of the left end bearing 3 itself. Therefore, the inner ring of the left end bearing 3 and the rotating shaft 21 are clearance-matched, and the second clearance 1145 (radial clearance, size is 1μm~3μm) between the two. The inner ring of the right end bearing 4 has a third clearance (radial clearance, size is 1μm~3μm) with the rotating shaft 21. The force and movement of the inner ring of the right end bearing 4 refer to the left end bearing 3.

[0063] The outer wall of the stator shell 11 is provided with a groove 1110 along the axial direction for placing the probe head 82 and the optical fiber 81 of the optical fiber pressure sensor 8. It should be noted that the probe head 82 of the optical fiber pressure sensor 8 needs to be placed near the blood outlet 71 of the impeller mounting tube 7 to reflect the required real-time blood pressure information. Therefore, according to the actual situation, the groove 1110 for placing the probe head 82 can be set on the left cover 112 or on the surface of the housing 111. The groove depth of the groove 1110 for placing the probe head 82 is 0.2mm-0.4mm, and the groove depth of the groove 1110 for placing the optical fiber 81 is 0.06mm-0.15mm. By providing a suitable size of the groove 1110, it is ensured that the optical fiber pressure sensor 8 is not easy to slip during installation and the placement position is relatively accurate. A small amount of biocompatible glue is then covered in the groove 1110 to completely fix the probe head 82 and the optical fiber 81, and the gaps and edges of the groove 1110 are filled and covered to prevent residual blood from coagulating. The optical fiber 81 is usually composed of several functional sub-wires, and the wire diameter is very small and easy to break. Therefore, when the optical fiber 81 extends to the right end (tail end) of the axial flow blood pump, it needs to be hidden inside the outer cover 1133 and extended outward through the outer sleeve 92. The length of the optical fiber 81 after extension and straightening is 1.3 to 1.8 meters.

[0064] The liquid passage tube 93 is made of biocompatible plastic (such as PA), and its length after straightening is 1.3 to 2.0 meters. The guide wire 91 can be inserted into the blind hole 1135 and fixed with biocompatible glue. The guide wire 91 is made of biocompatible nickel-titanium wire, and its length after straightening is 1.3 to 1.8 meters, with excellent toughness and metal memory function. After the axial flow blood pump is installed with the optical fiber pressure sensor 8, the guide wire 91 and the liquid passage tube 93, they are gathered together with the power cord 114 electrically connected to the magnetic winding of the blood pump motor to the tail end of the axial flow blood pump, and then the outer cover 1133 is installed.

[0065] The optical fiber 81 is introduced into the interior through the wiring hole 1136 on the side of the outer cover 1133. The wiring hole 1136 is covered with biocompatible glue. The glue must be evenly applied, the surface must be rounded, and the edges of the opening of the outer cover 1133 must be covered to reduce the risk of blood cell damage, residual blood coagulation, etc. Both ends of the outer cover 1133 are open and connected to the interior. Biocompatible potting glue is injected into the interior through the wiring hole 1136 to fill the internal gap, which can better fix and protect the guide wire 91, the liquid tube 93, the power line 114 and the root of the optical fiber 81.

[0066] The outer sleeve 92 wraps the guide wire 91, the liquid tube 93, the power cord 114 and the pressure sensor optical fiber 81 inside the outer sleeve 92, and has good toughness under the support of the guide wire 91. The front end of the axial blood pump (generally referred to as the proximal end) is equipped with a metal spiral braided catheter, an impeller mounting tube 7 with a blood inlet structure and an outlet structure, and a pigtail tube (not shown in the figure). Since the interventional pump is usually inserted through the inguinal artery of the human body, it is necessary to push a distance in the arterial blood vessel, so that the proximal end structure of the axial blood pump is finally located in the left ventricle, and the axial blood pump is located in the aorta. Under the action of the axial blood pump, the oxygenated blood of the left ventricle is directly pumped into the aorta to assist the circulation. During this surgical pushing process, the toughness support of the guide wire 91 is conducive to the advancement of the axial blood pump in the arterial blood vessel. In addition, the outer surface of the outer sleeve 92 is printed with scale bars and numbers with uniform spacing. During the operation, the doctor can use the scale bars and digital markings to assist in determining the pushing distance of the axial blood pump. At the same time, doctors can also judge the torsion of the axial blood pump during the pushing process based on the continuous marking lines along the axial direction.

[0067] It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An invasive axial blood pump, comprising an impeller mounting tube, a stator assembly, an optical fiber pressure sensor and a tail wrapping sealing device, wherein the stator assembly comprises a stator shell, a magnetic stator and a stator winding connected in sequence from outside to inside, the stator winding is connected to the left end of a power cord, the impeller mounting tube is mounted on the left end of the stator shell, and a blood outlet is provided on the impeller mounting tube, characterized in that: The optical fiber pressure sensor is mounted on the stator housing to measure the pressure of blood flowing out of the blood outlet, and the optical fiber pressure sensor has an optical fiber; The tail wrapping sealing device includes a right cover, an outer sleeve, a guide wire and a liquid passage tube. The right cover includes an outer cover, an inner cover and a tail cover. The inner cover and the tail cover are both located inside the outer cover. The left ends of the outer cover and the inner cover are respectively sealed and connected to the right end of the stator shell. The right end of the inner cover is fixedly connected to the left end of the tail cover. The outer surface of the outer cover includes a rotating surface, a cylindrical surface and a rough surface in sequence from left to right. The rough surface is formed by roughening a cylindrical curved surface. The outer sleeve is fixedly sleeved on the rough surface and the rough surface The rough surface and the outer sleeve are bonded with biocompatible glue, the outer diameter of the portion of the outer sleeve that is sleeved on the rough surface is consistent with the diameter of the cylindrical surface, the right end of the tail cover is provided with a through hole and a blind hole, the through hole of the tail cover is sealed and connected to the liquid passing tube, the left end of the liquid passing tube extends into the inner cavity of the inner cover, the blind hole of the tail cover is sealed and connected to the left end of the guide wire, the power cord, optical fiber and the right end of the liquid passing tube all pass through the outer cover and enter the outer sleeve, and the outer sleeve wraps the power cord, optical fiber, liquid passing tube and guide wire.

2. An invasive axial flow blood pump according to claim 1, characterized in that: A groove is provided on the outer side wall of the stator shell, the optical fiber pressure sensor is installed in the groove, the optical fiber pressure sensor does not exceed the outer side wall of the stator shell, the optical fiber extends along the groove and the right end of the optical fiber exceeds the right end of the groove; The outer cover is provided with a wiring hole so that the optical fiber can extend into the outer cover and then enter the outer casing. The wiring hole is sealed with biocompatible glue.

3. An invasive axial flow blood pump according to claim 2, characterized in that: The groove is covered with biocompatible glue for completely fixing the detection head and the optical fiber of the optical fiber pressure sensor, and the biocompatible glue fills and covers the gaps and edges of the groove to prevent residual blood from clotting.

4. The invasive axial flow blood pump according to claim 1, characterized in that: The liquid passage tube is made of biocompatible plastic and has a length of 1.3 to 2 meters after being straightened. The guide wire is made of biocompatible nickel-titanium wire material and has a length of 1.3 to 1.8 meters after being straightened.

5. The invasive axial flow blood pump according to claim 1, characterized in that: The right ends of the power cord, optical fiber, liquid passage tube and guide wire do not extend beyond the outer casing.

6. The invasive axial flow blood pump according to claim 2, characterized in that: The optical fiber pressure sensor also has a detection head connected to the optical fiber; For the groove, the groove depth of the portion for accommodating the detection head is 0.2 mm to 0.4 mm, and the groove depth of the portion for accommodating the optical fiber is 0.06 mm to 0.15 mm.

7. The invasive axial flow blood pump according to claim 1, characterized in that: The rotor assembly of the interventional axial flow blood pump comprises a rotating shaft, a permanent magnet and a rotor sleeve which are sequentially connected from the inside to the outside, and the stator housing comprises an outer shell and a left cover connected to the left end of the outer shell; The interventional axial blood pump further includes a left end bearing, a right end bearing, an impeller and a preload spring, wherein the left end bearing and the right end bearing are both ball bearings, the outer ring of the right end bearing is fixedly mounted on the right cover, and the preload spring is mounted on the rotating shaft; The left cover has a horizontal step hole, which is a through hole and includes a first hole, a second hole and a third hole which are arranged in sequence from left to right and whose diameters increase from small to large. The first step of the inner wall of the left cover forms the first hole and the second hole, and the second step of the inner wall of the left cover forms the second hole and the third hole. The left end of the rotating shaft passes through the left cover at the step hole and is connected to the impeller. There is a first gap between the hole wall of the first hole and the rotating shaft, and the first gap serves as an outlet for high-pressure liquid entering the motor housing. The outer ring of the left end bearing is fixedly mounted on the hole wall of the third hole and abuts against the second step. The outer diameter of the inner ring of the left end bearing is smaller than the hole diameter of the second hole. The inner ring of the left end bearing cooperates with the permanent magnet to clamp the preload spring, and the preload spring applies elastic force to the inner ring of the left end bearing. There are a second gap and a third gap between the inner ring of the left end bearing and the inner ring of the right end bearing and the rotating shaft respectively, the second gap enables the inner ring of the left end bearing to reciprocate along the axial direction of the rotating shaft under the elastic force of the preload spring and enables the inner ring of the left end bearing and the rotating shaft to still rotate synchronously, the third gap enables the inner ring of the right end bearing and the rotating shaft to still rotate synchronously, and a force transmission member is also fixedly installed on the rotating shaft, and the force transmission member applies force to the right on the inner ring of the right end bearing under the elastic force of the preload spring; The impeller mounting tube is fixedly mounted on the left cover and surrounds the impeller. The inner cavity of the impeller mounting tube is communicated with the first gap. The side wall of the impeller mounting tube is provided with the blood outlet at a position corresponding to the impeller.

8. The invasive axial flow blood pump according to claim 7, characterized in that: The first step is provided with a chamfer, thereby forming a bell mouth with a gradually decreasing diameter along the direction from the second hole to the first hole, so that the high-pressure liquid flows from the second hole into the first gap to fill the first gap, thereby reducing the risk of blood flowing back into the stator shell.

9. The invasive axial flow blood pump according to claim 8, characterized in that: The chamfer angle is 20° to 40°, that is, the included angle with the center line of the rotating shaft is 20° to 40°.

10. The invasive axial flow blood pump according to claim 7, characterized in that: The first gap is 5 μm to 15 μm, the second gap is 1 μm to 3 μm, and the third gap is 1 μm to 3 μm.

Images