Drive shaft of catheter pump, pump head assembly of catheter pump, and catheter pump

Abstract

Provided are a drive shaft of a catheter pump, a pump head assembly comprising the drive shaft, and a catheter pump. The drive shaft comprises a first drive shaft. The first drive shaft comprises a support section (21) and an impeller mounting section (22). The first drive shaft is sleeved inside a pump housing (1) of the catheter pump, and an impeller (3) in the pump housing (1) is sleeved inside and fixed to the impeller mounting section (22). The first drive shaft can slide axially relative to a bearing member. The support section (21) comprises a sliding fit section having a protective layer, and the hardness of the protective layer is greater than the hardness of the first drive shaft. When the first drive shaft axially slides distally relative to the bearing member to a first limit position, a proximal end position of the sliding fit section is located proximal to or coplanar with a proximal end face of the bearing member. When the first drive shaft axially slides proximally relative to the bearing member to a second limit position, a distal end position of the sliding fit section is located distal to or coplanar with a distal end face of the bearing member.

Description

Drive shaft of the duct pump, pump head assembly of the duct pump, and duct pump.

[0001] This application claims priority to Chinese Patent Application No. 202423322222.3, filed with the Chinese Patent Office on December 30, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of medical device technology, such as a drive shaft for a catheter pump, a pump head assembly for a catheter pump, and a catheter pump. Background Technology

[0003] An externally motorized catheter pump can be introduced into a patient via interventional procedures to assist in the transport of blood within the circulatory system. An externally motorized catheter pump typically consists of a pump head located inside the patient and a drive assembly located outside the patient's body. The drive assembly includes a drive shaft, which is generally housed within the catheter and connected to the pump head, thereby providing power to the pump head.

[0004] To provide stable support for the drive shaft, a bearing is installed inside the conduit to support the drive shaft. However, during actual operation of the conduit pump, because the motor is located outside the pump body, the drive shaft rotates at high speed during transmission, causing relative displacement between the drive shaft and the bearing components. This can cause wear on the drive shaft, and after a long period of wear, it will affect the bearing's support for the drive shaft, affecting the stable operation of the conduit pump, and may also generate particulate matter. Summary of the Invention

[0005] This application provides a drive shaft for a duct pump, a pump head assembly for a duct pump, and a duct pump, which can solve the technical problem in the related art where the drive shaft of a duct pump suffers severe wear and may generate particulate matter during use.

[0006] The following technical solution is adopted in this application:

[0007] The drive shaft of the duct pump includes:

[0008] The first drive shaft includes a support section and an impeller mounting section;

[0009] The first drive shaft is configured to pass through the pump casing of the duct pump, and the impeller inside the pump casing is fixed to the impeller mounting section.

[0010] The support section is configured to pass through a bearing member inside the pump housing, and the bearing member is configured to rotatably support the rotation of the support section so that the support section can rotatably support the first drive shaft inside the pump housing;

[0011] The first drive shaft is configured to drive the impeller to rotate, so as to pump blood from the blood inlet of the pump housing into the pump housing and pump it out from the blood outlet of the pump housing.

[0012] The first drive shaft is axially slidable relative to the bearing component, and the support section includes a sliding fit section with a protective layer, the hardness of which is greater than the hardness of the first drive shaft;

[0013] When the first drive shaft slides axially to the distal side relative to the bearing member to the first limit position, the proximal position of the sliding fit section is located near the proximal end face of the bearing member, or is coplanar with the proximal end face;

[0014] When the first drive shaft slides axially to the second limit position relative to the bearing member, the distal end of the sliding fit section is located on the far side of the distal end face of the bearing member, or is coplanar with the distal end face.

[0015] The pump head assembly of the duct pump includes:

[0016] The pump housing has a blood inlet and a blood outlet;

[0017] The drive shaft of the aforementioned conduit pump;

[0018] An impeller is located inside the pump casing and is mounted on the impeller mounting section fixed to the drive shaft. The drive shaft drives the impeller to rotate so as to pump blood from the blood inlet into the pump casing and pump it out from the blood outlet.

[0019] A conduit pump, including the drive shaft, drive assembly, and conduit of the aforementioned conduit pump;

[0020] The distal end of the drive assembly is connected to the proximal end of the conduit, and the distal end of the conduit is connected to the proximal end of the pump housing.

[0021] The drive assembly transmits rotational power to the pump casing via the drive shaft, thereby driving the impeller inside the pump casing to rotate. Attached Figure Description

[0022] Figure 1 is a structural schematic diagram of the duct pump provided in an embodiment of this application from one perspective;

[0023] Figure 2 is a structural schematic diagram of the duct pump provided in an embodiment of this application from another perspective;

[0024] Figure 3 is a schematic diagram of the catheter pump provided in the embodiment of this application when it is inserted into the heart;

[0025] Figure 4 is a schematic diagram of the pump head assembly provided in an embodiment of this application;

[0026] Figure 5 is a partial structural diagram of Figure 4;

[0027] Figure 6 is an enlarged view of point E in Figure 5;

[0028] Figure 7 is an enlarged view of point F in Figure 5;

[0029] Figure 8 is a schematic diagram of the coating range of the protective layer on the near-end bearing mating section provided in the embodiment of this application;

[0030] Figure 9 is a schematic diagram of the coating range of the protective layer on the mating section of the distal bearing provided in the embodiment of this application.

[0031] In the diagram: 10. Pump head assembly; 20. Drive assembly; 30. Conduit; 40. Protective head; 1. Pump casing; 11. Bracket; 12. Membrane cover; 14. First stop; 2. Drive shaft; 21. Support section; 211. Proximal section; 212. Distal section; 22. Impeller mounting section; 3. Impeller; 4. Proximal bearing component; 5. Distal bearing component; 51. Support surface; 7. Second stop. Detailed Implementation

[0032] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0035] This embodiment provides a conduit pump.

[0036] Alternatively, as shown in Figures 1-3, the catheter pump typically needs to be at least partially inserted into the patient's body, for example, it can be deployed at a predetermined location in the left or right ventricle to pump blood to at least partially replace the heart's pumping function.

[0037] The duct pump includes a duct 30, a drive assembly 20, and a pump head assembly 10. The drive assembly 20 includes a drive shaft 2. The drive assembly 20 is connected to the proximal end of the duct 30 via a coupler and provides power as a power source. The distal end of the duct 30 is connected to the pump head assembly 10. The drive shaft 2 is internally disposed within the duct 30, and the proximal end of the drive shaft 2 is connected to the power output end of the drive assembly 20. The distal end of the duct 30 is connected to the pump head assembly 10.

[0038] The pump head assembly 10 includes a pump housing 1 and an impeller 3 mounted within the pump housing 1, the impeller 3 being connected to the distal end of a drive shaft 2. Thus, when the drive shaft 2 rotates, it drives the impeller 3 to rotate as well. The pump housing 1 includes a metal lattice support 11 made of, for example, an alloy such as nickel or titanium. The metal lattice of the pump housing 1 has a mesh design. A diaphragm 12, together with the pump housing 1, defines a blood inlet for pumping blood in and a blood outlet for pumping blood out. In some embodiments, the diaphragm 12 covers the middle and rear end portion of the pump housing 1 (i.e., the proximal portion near the pump housing 1), whereby the diaphragm 12 can form a blood outlet for pumping blood out at the proximal end, and the portion of the pump housing 1 not covered by the diaphragm 12 can form a blood inlet for pumping blood in, for example, through the mesh of the pump housing 1. When the drive shaft 2 drives the impeller 3 to rotate, blood enters from the blood inlet into the fluid channel defined by the diaphragm 12 along with the rotation of the impeller 3, and flows out from the blood outlet through the diaphragm 12.

[0039] In some embodiments, the pump head assembly 10 has a folded configuration and an extended configuration; the conduit pump also includes a folded sheath, under the folding force of the folded sheath, the pump head assembly 10 is compressed to the folded configuration; when the pump head assembly 10 is removed from the folded sheath, the pump head assembly 10 gradually returns to the extended configuration.

[0040] This configuration offers advantages in the interventional use of catheter pumps. The pump head assembly 10 and the tip portion of the catheter 30 are inserted into and held within the patient's body; therefore, the peripheral dimensions of the pump head assembly 10 and the catheter 30 should be as small as possible. Smaller pump head assembly 10 and catheter 30 mean that they can be inserted into the patient's body through a smaller puncture site, reducing patient discomfort during the interventional procedure and minimizing complications caused by excessively large puncture sites. In one possible embodiment, the pump head assembly 10 is in a folded configuration, thus occupying the smallest possible peripheral dimension; this folded configuration corresponds to the interventional procedure of the catheter pump. In an unfolded configuration, the pump head assembly 10 returns from the folded configuration to the unfolded configuration; this unfolded configuration corresponds to the operating state of the catheter pump, in which the blood pumping fluid channel of the pump head assembly 10 is unobstructed and suitable for pumping blood.

[0041] In some embodiments, the pump housing 1 of the pump head assembly 10 may be made of an alloy material such as nickel-titanium. The pump head assembly 10 may be implemented with a multi-mesh design and simultaneously utilize the shape memory properties of the nickel-titanium alloy to achieve deployment. The blades of the impeller 3 are made of a flexible material or a shape memory material and can fold relative to the hub. In the deployed configuration of the pump head assembly 10, the blades of the impeller 3 are close to the hub to reduce the size they occupy. After the external force constraining the blades of the impeller 3 is released, the energy stored in the blades is released, causing the blades to deploy and return to the deployed configuration.

[0042] The catheter pump also includes a protective head 40 connected to the distal end of the pump head assembly 10. The protective head 40 guides the insertion of the catheter pump into the predetermined location in the body. After the catheter pump has been inserted into the predetermined location (i.e., after the catheter pump is deployed), the protective head 40 maintains the pump head's position within the heart during operation, preventing the pump head from adhering to the endocardial wall or aspirating the chordae tendineae into the pump head, thus preventing potential danger. The protective head 40 is flexible and therefore does not damage the patient's tissues. In some embodiments, the flexible end of the protective head 40 is supported against the ventricular wall in a non-invasive or non-damaging manner, separating the inlet of the pump head assembly 10 from the ventricular wall. Optionally, the protective head 40 is linear in shape. In other embodiments, the protective head 40 may be any other suitable shape.

[0043] Figure 3 illustrates a schematic diagram of the catheter pump deployed in the left ventricle according to this embodiment, with the diaphragm 12 extending proximally beyond a portion of the stent 11 across the heart valve. It should be understood that the illustrated embodiment is merely exemplary, and the catheter pump can also be inserted into other target locations in the patient, such as the right ventricle, blood vessels, or other organs, via interventional procedures.

[0044] In one possible embodiment, the catheter pump is used to assist in the treatment of heart failure. When the pump head assembly 10 of the catheter pump is positioned in the left ventricle, the catheter pump can assist in pumping blood from the heart into the aorta, thus restoring some of the heart's pumping function. In scenarios applicable to left ventricular assist, the catheter pump pumps blood from the left ventricle into the aorta to support blood circulation, reduce the workload of the subject's heart, or provide additional continuous pumping power support when the heart's pumping capacity is insufficient.

[0045] When the catheter pump is in use, the drive assembly 20 is located outside the subject's body. The end of all components closest to the drive assembly 20 is the proximal end, and the other end furthest from the drive assembly 20 is the distal end.

[0046] The state of the catheter pump during operation is shown in Figures 3-5. The protective head of the pump head assembly 10 (i.e., the distal end in Figure 4) usually needs to be pressed against the ventricular wall to stabilize the pump head. Since the distal end of the protective head is relatively flexible, the distal end of the protective head is generally bent at a large angle.

[0047] The pump head assembly includes a drive shaft 2. The drive shaft 2 includes a first drive shaft that passes through the pump casing of the duct pump.

[0048] As the heart contracts and expands, the ventricular wall exerts a radial force on the protective head. This radial force is transmitted through the protective head and the bracket fixedly connected to it to the bearing within the pump housing 1, which supports the rotation of the first drive shaft. However, due to the radial force transmitted from the protective head, the bearing will deflect at an angle relative to the first drive shaft. As a result, the mating surface between the first drive shaft and the bearing will shift, causing wear on the first drive shaft caused by the bearing.

[0049] In addition, the first drive shaft will also undergo axial displacement relative to the bearing components, which will also cause wear on the first drive shaft caused by the bearing components.

[0050] In order to reduce or avoid wear of the drive shaft 2 and the resulting particulate matter, this application provides a drive shaft and pump head assembly for a conduit pump. By providing a protective layer at the part where the drive shaft mates with the bearing, the technical problem of drive shaft wear mentioned above can be solved.

[0051] Referring to Figures 4-7, the pump head assembly 10 also includes a pump housing 1 and an impeller 3.

[0052] The pump housing 1 has a blood inlet and a blood outlet.

[0053] Impeller 3 is mounted on the first drive shaft of drive shaft 2. The first drive shaft can drive impeller 3 to rotate, so as to pump blood from the blood inlet of pump housing 1 into pump housing 1 and pump it out from the blood outlet of pump housing 1.

[0054] To support and drive the impeller to rotate within the pump casing, the aforementioned first drive shaft includes a support section 21 and an impeller mounting section 22. The support section 21 rotatably supports the first drive shaft within the pump casing, while the impeller mounting section 22 mounts and fixes the impeller. Optionally, the impeller 3 within the pump casing 1 passes through and is fixed to the impeller mounting section 22.

[0055] Optionally, the support section 21 is disposed through a bearing member inside the pump housing 1, the bearing member being used to rotatably support the rotation of the support section 21 so as to rotatably support the entire first drive shaft inside the pump housing.

[0056] As described in the previous embodiment, the drive assembly 20 of the catheter pump is located outside the subject's body, while the pump head assembly 10 is located inside the body. The transmission path between the drive assembly 20 and the impeller 3 is long and bends with the vascular system. Therefore, the drive shaft 2 needs to be made into a flexible shaft or a drive shaft including a flexible segment. In order to adapt to the above structural characteristics of the externally mounted catheter pump, the first drive shaft and the bearing need to be slidably connected so that the first drive shaft can slide axially relative to the bearing to reduce or avoid the adverse effects of the long and bendable transmission path on the transmission effect and maintain the stability of the drive shaft driving the impeller 3 to rotate.

[0057] This connection method may lead to wear of the bearing components on the first drive shaft and the generation of particulate matter. As mentioned above, the wear is caused partly by the rotational friction between the first drive shaft and the bearing components, and partly by the radial force exerted by the ventricular wall on the protective head when the heart beats, which exacerbates the friction between the bearing components and the first drive shaft.

[0058] To protect the main body of the first drive shaft and reduce or avoid wear on the first drive shaft from the bearing components, the aforementioned support section 21 includes a sliding fit section with a protective layer. The hardness of this protective layer is greater than that of the first drive shaft. By coating the sliding fit section with a protective layer, the wear resistance, bending moment resistance, and impact resistance of the sliding fit section that mates with the bearing components are increased. This prevents the bearing components from directly contacting the main body of the first drive shaft, and rotational friction occurs within the smooth and relatively hard protective layer, thereby reducing or avoiding wear on the first drive shaft from the bearing components and the generation of related particulate matter.

[0059] Regarding the selection of the protective layer, it must be at least one of the following: diamond-like carbon (DLC) coating, physical vapor deposition (PVD) molybdenum disulfide coating, nitride coating, or ceramic coating. When applying the protective layer, it can be a single coating from the initial position, or it can be a multi-segment coating along the axial direction, with different segments of the coating of different types. The protective layer can be a single-layer coating or a multi-layer coating, and the types of protective layers can be different or the same.

[0060] Optionally, the first drive shaft is a hard shaft with a hardness of 200HV-700HV. After the protective layer is set, the hardness of the sliding mating section is greater than or equal to 1800HV.

[0061] In one embodiment, the hardness of the sliding fit section is greater than or equal to 2500 HV. The first drive shaft described above can also be a flexible shaft, and this application does not limit this.

[0062] Optionally, the surface roughness of the protective layer is less than Ra1.0.

[0063] In one embodiment, the surface roughness of the protective layer is less than Ra0.4. Exemplarily, the surface roughness of the protective layer is Ra0.3, Ra0.2, or Ra0.1.

[0064] Furthermore, considering the structural characteristics that axial sliding and axial displacement will occur between the first drive shaft and the aforementioned bearing components, it is necessary to determine the start and end positions of the sliding fit section in the support section 21, that is, to determine the start and end positions of the protective layer coating. The sliding fit section should at least be a portion of the support section 21 that is slidably connected to the bearing components and coated with a protective layer. Optionally, the positions of the two ends of the sliding fit section should satisfy the following conditions:

[0065] When the first drive shaft slides axially to the far side relative to the bearing component to the first limit position, the proximal position of the sliding fit section is located near the proximal end face of the bearing component, or is coplanar with the proximal end face;

[0066] When the first drive shaft slides axially toward the bearing component to the second limit position, the far end of the sliding fit section is located far from the far end face of the bearing component, or is coplanar with the far end face.

[0067] In this way, when radial or axial movement occurs between the first drive shaft and the bearing component, even if the relative displacement reaches the limit distance in either direction, the edge of the bearing component will not exceed the edge of the sliding fit section. The bearing component can always slide fit with the sliding fit section with the protective layer, reducing or avoiding wear of the first drive shaft and the generation of particulate matter.

[0068] Furthermore, by determining the start and end positions of the sliding fit section based on the aforementioned conditions for protective layer coating, it is unnecessary to coat the entire first drive shaft with a protective layer. This reduces coating costs, minimizes or avoids waste of coating material, and does not affect the installation and fixation of other components on the first drive shaft. For example, if the impeller is fixed to the impeller mounting section 22, and the impeller mounting section 22 is also coated with a protective layer, the presence of this part of the protective layer, due to its hardness and smoothness, would affect the firmness and stability of the impeller 3 on the first drive shaft. In one possible implementation, to achieve a firm connection between the impeller mounting section 22 and the impeller, the outer circumferential surface of the impeller mounting section 22 is roughened, forming multiple surface protrusions. If the protective layer extends to the impeller mounting section 22, the coating material will fill the spaces between these protrusions, resulting in an unreliable connection between the impeller mounting section 22 and the impeller 3. If the impeller mounting section 22 is not coated with a protective layer, the spaces between these protrusions will be filled by the impeller material, achieving a firm connection between the impeller 3 and the impeller mounting section 22.

[0069] The pump head assembly 10 provided in this embodiment is applied to a catheter pump. When the catheter pump is implanted in the human body, the pump head assembly 10 exerts a radial force on the protective head as the heart contracts and expands. This radial force is transmitted to the bearing component inside the pump housing 1 through the protective head and the bracket fixedly connected to the protective head. However, due to the protective layer on the sliding fit section, when the drive shaft 2 undergoes axial or radial displacement relative to the bearing component, the bearing component is always in contact with the protective layer, thereby avoiding wear of the bearing component on the drive shaft.

[0070] In addition to defining the start and end positions of the sliding fit section, the number of sliding fit sections also needs to be set according to the number of bearing components inside the guide pump. The number of bearing components can be single or multiple, and this application embodiment does not limit this. Those skilled in the art can set a sliding fit section for each bearing component separately, or they can set a single sliding fit section for multiple bearing components, and this application embodiment does not limit this either.

[0071] In one possible implementation, the pump head assembly 10 includes only a single bearing located near the impeller 3, forming a cantilever support structure for the impeller 3. This bearing can be located either near or far from the impeller 3. Therefore, a protective coating can be applied to the support section 21 of the first drive shaft on the side where the bearing is located, forming the aforementioned sliding fit section. The cantilever support structure is suitable for duct pumps with an internal motor, where both the drive motor and impeller 3 are located at the pump head, resulting in a short transmission distance. The motor shaft can be directly and rigidly connected to the impeller, in which case there is no displacement between the motor shaft and the bearing. The cantilever support structure is also suitable for duct pumps with an external motor, but axial sliding and radial offset (radial offset can also be caused by the thrust of blood on the impeller) will occur between the first drive shaft and the bearing as described above. Therefore, the start and end positions of the sliding fit section need to be limited according to the conditions that the sliding fit section needs to meet.

[0072] In another possible implementation, the pump head assembly includes at least two bearing members, which are located at both ends of the impeller 3. The first drive shaft includes at least two support sections 21, which are respectively inserted to form a double-end support structure for the impeller 3. The double-end support structure is more suitable for duct pumps with the drive assembly 20 externally mounted, and the rotation of the impeller 3 in the pump casing 1 is more stable. The pump head assembly with the double-end support structure will be described below.

[0073] Referring to Figures 5 and 6, the bearing assembly near the impeller 3 includes a proximal bearing 4 located near the pump housing 1, and the support section 21 includes a proximal section 211 located near the impeller mounting section 22. The proximal section 211 passes through the proximal bearing 4, which rotatably supports the rotation of the proximal section 211. Optionally, the proximal bearing 4 is an annular bearing.

[0074] In order to reduce or avoid severe wear of the proximal bearing component 4 on the first drive shaft, in this embodiment, the proximal section 211 includes a proximal bearing mating section with a protective layer, and the aforementioned sliding mating section includes the proximal bearing mating section.

[0075] The aforementioned proximal section 211 is a proximal support section located near the impeller 3 and mating with the proximal bearing component 4. This proximal bearing mating section should at least be a portion of the proximal section that slides into contact with the proximal bearing component 4 and is coated with a protective layer. The protective layer on the proximal bearing mating section prevents contact between the inner ring surface of the proximal bearing component 4 and the shaft of the proximal bearing mating section. Optionally, the positions of both ends of the proximal bearing mating section satisfy the following conditions:

[0076] When the first drive shaft slides axially to the distal end relative to the proximal bearing member 4 to the first limit position, the proximal end of the proximal bearing mating section is located near the proximal end face of the proximal bearing member 4, or is coplanar with the proximal end face of the proximal bearing member 4. When the first drive shaft slides axially to the proximal end relative to the proximal bearing member 4 to the second limit position, the distal end of the proximal bearing mating section is located far from the distal end face of the proximal bearing member 4, or is coplanar with the distal end face of the proximal bearing member 4. This configuration ensures that the proximal bearing member 4 remains in contact with the protective layer on the proximal bearing mating section during the relative movement of the first drive shaft and the proximal bearing member 4, reducing or avoiding excessive wear of the proximal bearing member 4 on the first drive shaft and the generation of particulate matter.

[0077] Referring to Figures 5 and 7, the bearing assembly, distal to the impeller 3, includes a distal bearing 5 located distal to the pump casing. The support section 21 includes a distal section 212, located distal to the impeller mounting section 22. During operation, as the heart contracts and expands, the ventricular wall exerts a radial force on the protective head. This radial force is transmitted through the protective head and a bracket fixedly connected to it to the distal bearing 5 within the pump casing 1. The distal section 212 passes through the distal bearing 5, which rotatably supports the rotation of the distal section 212. Optionally, the distal bearing 5 is an annular bearing.

[0078] In order to reduce or avoid severe wear of the first drive shaft by the distal bearing component 5, in this embodiment, the distal section 212 includes a distal bearing mating section with a protective layer, and the aforementioned sliding mating section includes the distal bearing mating section.

[0079] The aforementioned distal section 212 is a distal support section located on the far side of the impeller 3 and mating with the distal bearing component 5. This distal bearing mating section should at least be a portion of the distal section that is slidably connected to the distal bearing component 5 and coated with a protective layer. The protective layer on the distal bearing mating section prevents contact between the inner ring surface of the distal bearing component 5 and the shaft of the distal bearing mating section. Optionally, the positions of both ends of the distal bearing mating section satisfy the following conditions:

[0080] When the first drive shaft slides axially to the first limit position relative to the distal bearing member 5, the proximal position of the distal bearing mating section is located on the proximal side of the proximal end face of the distal bearing member 5, or is coplanar with the proximal end face of the distal bearing member 5.

[0081] When the first drive shaft slides axially to the proximal side relative to the distal bearing member 5 to the second limit position, the distal end position of the distal bearing mating section is located on the far side of the distal end face of the distal bearing member 5, or is coplanar with the distal end face of the distal bearing member 5.

[0082] By installing protective layers on the support sections at both ends of the impeller, and ensuring that the sliding fit sections with protective layers at both ends are always in contact with the bearing components, the wear of the double-end bearing components on the support sections at both ends of the impeller and the generation of related particulate matter can be reduced or avoided.

[0083] The first extreme position mentioned above is the extreme position where the first drive shaft moves axially to the distal end relative to the bearing component, at which point the distance between the distal end of the first drive shaft and the distal end of the bearing component reaches its maximum. The second extreme position is the extreme position where the first drive shaft moves axially to the proximal end relative to the bearing component, at which point the distance between the proximal end of the first drive shaft and the proximal end of the bearing component reaches its maximum. The above two extreme positions can be determined in various ways, such as based on the actual structure of the duct pump and experimental analysis, and are not limited in this embodiment.

[0084] To limit the relative displacement between the bearing and the first drive shaft, a stop can be added to the pump head assembly 10. In some possible embodiments, a stop is provided inside the pump housing 1 to abut against the bearing or the first drive shaft to limit the axial sliding of the first drive shaft and to facilitate the determination of the end position of the sliding fit section.

[0085] With the aforementioned stop provided, the end position of one end of the sliding fit section is located at the junction of the stop and the first drive shaft. This junction position can be the edge position where rotational friction occurs when the stop abuts against the bearing or the first drive shaft. Setting a certain end position of the sliding fit section at this junction position allows the protective layer of the sliding fit section to cover the limit position of the relative displacement between the bearing and the first drive shaft.

[0086] Since the stop may come into contact with and rub against the bearing or the first drive shaft, the stop is also provided with a protective layer to reduce or avoid wear between the stop and the bearing and / or between the stop and the first drive shaft.

[0087] Furthermore, in terms of manufacturing process, it is difficult to control the position of one end of the protective layer at the axial position of the end face of the stop member. Therefore, a protective layer is provided on the stop member to reduce the difficulty of coating the protective layer. Optionally, a protective layer is provided on the end face of the stop member that abuts against the bearing member or the first drive shaft. Optionally, a protective layer is also provided on the outer peripheral surface of the stop member.

[0088] The following describes an embodiment of a pump housing with a stop member, using Figure 6 as an example. The stop member includes a first stop member 14 fixedly sleeved on the outer periphery of the first drive shaft. The bearing member includes a proximal bearing member 4 located near the pump housing. The first drive shaft also passes through a second stop member 7 within the pump housing 1. The proximal bearing member 4 is located far from the second stop member 7. The first stop member 14 slides axially between the second stop member 7 and the proximal bearing member 4 to restrict the axial sliding of the first drive shaft.

[0089] The distal end of the first stop member 14 is used to abut against the proximal bearing member 4 to restrict the movement of the first drive shaft to the distal side, and the second stop member 7 is used to abut against the first drive shaft with the first stop member 14 to restrict the movement of the first drive shaft to the proximal side.

[0090] When the first stop 14 abuts against the proximal bearing 4, the first drive shaft slides axially to the distal side relative to the proximal bearing 4 to the first limit position; when the first stop 14 abuts against the second stop 7, the first drive shaft slides axially to the proximal side relative to the proximal bearing 4 to the second limit position.

[0091] In another embodiment, the stop includes a distal stop portion of the distal bearing housing for abutting against the distal end face of the first drive shaft to limit the displacement of the first drive shaft toward the distal end. The distal stop portion may be the distal inner wall of the distal bearing housing or a retaining ring disposed on the distal inner wall; this embodiment does not limit the specific type of stop.

[0092] The aforementioned stop members include, but are not limited to, at least one of the first stop member 14 and the second stop member 7 in the near-end bearing housing and the far-end stop portion in the far-end bearing housing.

[0093] Those skilled in the art can determine the start and end positions of the sliding fit section coated with the protective layer based on the above description of the axial sliding limit position and in conjunction with the actual conduit pump. Several specific implementation methods are provided herein for reference.

[0094] In one possible implementation, as shown in FIG6, the drive shaft 2 slides to the distal limit position.

[0095] The stop component includes a first stop component 14 that is fixedly sleeved on the outer periphery of the first drive shaft.

[0096] Optionally, in one possible embodiment, the proximal end of the proximal bearing mating section is located at the junction of the first drive shaft and the first stop 14, wherein the first stop 14 is sleeved on the outer periphery of the first drive shaft and located on the proximal side of the proximal bearing 4 to restrict the axial sliding of the first drive shaft.

[0097] And / or, when the first drive shaft slides axially to the second limit position relative to the proximal bearing member 4, the distal position of the proximal bearing mating section extends 1mm-5mm beyond the distal end face of the proximal bearing member 4.

[0098] When the first drive shaft moves axially, the first stop 14 can move to abut against the proximal bearing 4. The proximal position of the proximal bearing mating section is set at the junction of the first drive shaft and the first stop 14, and a protective layer is provided on the proximal bearing mating section. This can reduce or avoid wear on the first drive shaft caused by the proximal bearing 4 when the first drive shaft moves to the far end.

[0099] When the first stop 14 moves to abut against the proximal side of the proximal bearing 4, the first stop 14 can restrict the first drive shaft from continuing to move to the distal end.

[0100] By using the junction of the first drive shaft and the first stop 14 as the starting point for coating the protective layer on the near end of the bearing mating section, it can be ensured that the entire drive shaft between the near end bearing 4 and the impeller 3 is covered with a protective layer. Thus, even if the drive shaft and the near end bearing 4 experience radial offset and / or axial sliding during the operation of the duct pump, the near end of the near end bearing 4 can still contact the protective layer, rather than directly contacting the shaft body of the drive shaft, thereby reducing or avoiding wear on the drive shaft and the resulting particulate matter.

[0101] Furthermore, since the relative displacement between the drive shaft and the proximal bearing 4 is mainly caused by the heartbeat contacting the protective head, and the contraction and expansion range of the heart is limited, when the drive shaft and the proximal bearing 4 move to their two extreme positions, the distal end of the protective layer coating on the proximal bearing mating section extends 1mm-5mm beyond the edge face of the proximal bearing 4. This further ensures that the part of the drive shaft in contact with the proximal bearing 4 is protected by the protective layer, further reducing or avoiding wear on the drive shaft and wear-generated particulate matter. Optionally, the first stop 14 is welded to the outer periphery of the proximal section 211. To facilitate the installation of the first stop 14, no protective layer is provided on the outer peripheral surface of the drive shaft 2 in contact with the first stop 14. The first stop 14 is first welded to the drive shaft 2, and then the protective layer is applied.

[0102] Optionally, in one possible embodiment, the proximal position of the distal bearing mating section is the axial position of the distal end face of the impeller mounting section 22, or, when the first drive shaft slides axially to the distal side relative to the distal bearing member 5 to the first limit position, the proximal position of the distal bearing mating section extends proximally beyond the proximal end face of the distal bearing member 5 by 0.5mm-2.0mm.

[0103] And / or, when the first drive shaft slides axially to the second limit position relative to the distal bearing member 5, the distal position of the distal bearing mating section extends distally beyond the distal end face of the distal bearing member 5 by 0.5mm-2.0mm.

[0104] Since the relative displacement between the drive shaft and the distal bearing 5 is partly caused by the heartbeat contacting the protective head, and the contraction and expansion range of the heart is limited, when the drive shaft and the distal bearing 5 move relative to each other to the first extreme position, the proximal end of the protective layer of the distal bearing mating section extends proximally beyond the proximal end face of the distal bearing 5 by 0.5mm-2.0mm. This further ensures that the part of the drive shaft in contact with the distal bearing 5 is protected by the protective layer, further reducing or avoiding wear on the drive shaft and the particulate matter generated by wear. Similarly, when the drive shaft and the distal bearing 5 move relative to each other to the second extreme position, the distal end of the distal bearing mating section extends distally beyond the distal end face of the distal bearing 5 by 0.5mm-2.0mm. This further ensures that the part of the drive shaft in contact with the distal bearing 5 is protected by the protective layer, further reducing or avoiding wear on the drive shaft and the particulate matter generated by wear.

[0105] In one possible embodiment, using the axial position of the distal end face of the impeller mounting section 22 as the proximal starting position of the protective coating on the distal bearing mating section ensures that the entire drive shaft between the distal bearing component 5 and the impeller 3 is covered with the protective layer. Thus, even during the operation of the duct pump, if the drive shaft and the distal bearing component 5 experience radial offset and / or axial sliding, the proximal end of the distal bearing component 5 can contact the protective layer, rather than directly contacting the shaft body of the drive shaft, thereby reducing or avoiding wear on the drive shaft and the resulting particulate matter.

[0106] Referring to Figure 6, in one possible embodiment, the proximal bearing mating section of the proximal section 211 has a proximal position and a distal position. The proximal position of the proximal bearing mating section is located at the proximal end of the junction between the proximal end face of the proximal bearing member 4 and the outer peripheral surface of the proximal section 211, and the distal position of the proximal bearing mating section is located at the distal end of the junction between the distal end face of the proximal bearing member 4 and the outer peripheral surface of the proximal section 211. A protective layer on the proximal bearing mating section is disposed between the proximal position and the distal position of the proximal bearing mating section.

[0107] In Figure 6, the circumferential position of point A on the proximal section 211 represents the proximal position of the proximal bearing mating section, and the circumferential position of point B on the proximal section 211 represents the distal position of the proximal bearing mating section. The protective layer on the proximal bearing mating section is located between points A and B.

[0108] In Figure 6, the distance between point B and the distal end face of the near-end bearing 4 is 1mm-5mm; for example, in Figure 6, the distance between point B and the distal end face of the near-end bearing 4 is 2mm, 3mm or 4mm.

[0109] Referring to Figure 7, the distal segment 212 has a proximal position of the distal bearing mating segment and a distal position of the distal bearing mating segment. The proximal position of the distal bearing mating segment is located near the distal end of the distal bearing component 5, and the distal position of the distal bearing mating segment is located far from the distal end of the distal bearing component 5. The protective layer of the distal bearing mating segment is disposed between the proximal position of the distal bearing mating segment and the distal position of the distal bearing mating segment.

[0110] Optionally, when the drive shaft 2 slides to its extreme position relative to the bearing member, the proximal end position of the proximal bearing mating section is coplanar with or located near the proximal end face of the proximal bearing member 4, and the proximal end position of the distal bearing mating section is located near or coplanar with the proximal end face of the distal bearing member 5; and / or,

[0111] When the drive shaft slides to its limit position relative to the bearing component, the far end of the near end bearing mating section is located on the far side of the far end face of the near end bearing component 4 or is coplanar with the far end face of the near end bearing component 4, and the far end of the far end bearing mating section is located on the far side of the far end face of the far end bearing component 5 or is coplanar with the far end face of the far end bearing component 5.

[0112] In one possible embodiment, when the drive shaft 2 slides to its extreme position relative to the bearing member, the proximal end of the proximal bearing mating section is coplanar with the proximal end face of the proximal bearing member 4, and the proximal end of the distal bearing mating section is located near the proximal end face of the distal bearing member 5, as shown in Figure 6. Simultaneously, when the drive shaft 2 slides to its extreme position relative to the bearing member, the distal end of the proximal bearing mating section is located far from the distal end face of the proximal bearing member 4, and the distal end of the distal bearing mating section is located far from the distal end face of the distal bearing member 5, as shown in Figure 7. This configuration effectively prevents wear on the drive shaft caused by the bearing member.

[0113] In one possible embodiment, when the first stop 14 abuts against the proximal end face of the proximal bearing member 4, the proximal position of the distal bearing mating section extends proximally beyond the proximal end face of the distal bearing member 5 by a distance of 0.5mm-2.0mm. Optionally, the proximal position of the distal bearing mating section is the axial position where the distal end face of the impeller mounting section is located.

[0114] And / or, the far end position of the far end bearing mating section extends far beyond the farthest end of the far end bearing 5 mating with the first drive shaft, by a distance of 0.5mm-2.0mm, or, the far end position of the far end bearing mating section is located at the far end face of the drive shaft 2.

[0115] In Figure 7, point C represents the near end position of the far-end bearing mating section, and point D represents the far end position of the far-end bearing mating section. The protective layer of the far-end bearing mating section is located between points C and D.

[0116] When the drive shaft 2 moves to its far limit position, point C is located near the proximal end face of the far bearing component 5. Optionally, the distance between point C and the proximal end face of the far bearing component 5 at this time is 0.5mm-2.0mm.

[0117] When the drive shaft 2 moves to its near-end limit position, point D is located on the far side of the far end face of the far end bearing 5. Optionally, the distance between point D and the far end face of the far end bearing 5 at this time is 0.5mm-2.0mm.

[0118] In one possible embodiment, the starting position of the distal bearing mating section from the proximal end to the distal end is located at the axial position of the distal end face of the impeller mounting section 22.

[0119] Optionally, a protective layer is also provided between the far end of the far end of the bearing mating section and the far end face of the drive shaft 2 to reduce the difficulty of applying the protective layer on the far end bearing mating section.

[0120] In one possible embodiment, when the drive shaft 2 moves to the proximal limit position, that is, the second limit position, the proximal end face of the first stop member 14 will move with the drive shaft 2 to abut against the distal end face of the second stop member 7. At this time, point B will move to be coplanar with the distal end face of the proximal bearing member 4 or extend to the distal end face of the proximal bearing member 4.

[0121] Alternatively, when forming the protective layer, the protective layer can be formed between point A and point B.

[0122] However, to improve the ease of coating operations, a protective layer may optionally be coated on the distal end face of the first stop 14.

[0123] Due to the small size of the product, to reduce operational difficulty, when actually coating the protective layer on the near-end bearing mating section, the protective layer is applied along the outer peripheral surface of the first stop 14, the distal end face of the first stop 14, and between the proximal and distal ends of the near-end bearing mating section. For example, the protective layer is applied from the proximal end of the outer peripheral surface of the first stop 14 to the distal end of the near-end bearing mating section. This arrangement simplifies the coating process, reduces the difficulty of coating the protective layer, and effectively prevents the near-end bearing 4 from causing wear on the drive shaft 2. Simultaneously, it also prevents frictional damage between the first stop 14 and the near-end bearing 4.

[0124] Referring to Figure 8, the area covered by the protective coating on the near-end bearing mating section is indicated by a bold black line.

[0125] When actually coating the protective layer on the distal bearing mating section, the protective layer is applied both at the proximal end of the distal bearing mating section and at the distal end of the first drive shaft. This arrangement simplifies the coating process, reduces the difficulty of coating the protective layer, and effectively prevents the distal bearing component 5 from causing wear on the drive shaft 2. Simultaneously, it also prevents frictional damage between the distal end of the distal bearing housing (such as the distal inner wall or a stop component located at the distal end of the distal bearing housing) and the distal end of the first drive shaft.

[0126] Referring to Figure 9, the area covered by the protective coating on the far-end bearing mating section is indicated by a bold black line.

[0127] The pump head assembly provided in this embodiment does not have a protective layer on the entire drive shaft 2. This design avoids increasing costs.

[0128] Meanwhile, in one possible embodiment, no protective layer is provided on the impeller mounting section 22 that mates with the impeller 3, so as to avoid affecting the radial dimension of the impeller mounting section 22 and thus affecting the assembly of the impeller 3.

[0129] Because the pump head assembly of the catheter pump is inserted into the human body and there are gaps within the pump head assembly, it is necessary to pre-charge the catheter pump when using it so that the flushing fluid fills the gap between the catheter pump and the cardiovascular system. During the operation of the catheter pump, flushing fluid is continuously injected into the catheter pump so that the flushing fluid flows to the gaps outside the drive shaft, such as the gap between the drive shaft and the catheter, and the gap between the drive shaft and the bearing components.

[0130] The coating application also needs to consider the smooth flow of flushing fluid between the sliding fit section and the bearing component. Optionally, the sliding fit section is provided with an axial groove for the flushing fluid to pass through the bearing component. The axial groove is formed based on a groove in the shaft body of the sliding fit section, or based on the coating structure of the protective layer.

[0131] When the axial groove is formed based on the groove of the shaft in the sliding fit section, the protective layer is coated on all or part of the outer peripheral surface of the sliding fit section, and the part of the outer peripheral surface includes the non-groove outer peripheral surface other than the axial groove.

[0132] The aforementioned axial groove may extend through the entire sliding fit section or through the main part of the sliding fit section; however, this application does not limit this.

[0133] In the case where the drive shaft and bearing components can slide relative to each other or be radially offset, the inner wall of the axial groove will not contact the inner surface of the bearing component, regardless of the positional change. Therefore, a protective layer can be applied to the axial groove or not. At least applying a protective layer to the outer circumferential surface of the non-groove part is sufficient to protect the drive shaft, while the flushing fluid can pass smoothly through the groove.

[0134] In the case where the axial groove is formed based on the coating structure of the protective layer, the protective layer includes multiple coating strips that are axially continuous, and the axial groove between the multiple coating strips is formed to allow flushing fluid to pass through the bearing element.

[0135] The protective layer can be applied directly in strip form or with varying sizes and thicknesses to protect the drive shaft without requiring grooves in the shaft, while also improving the permeability of the flushing fluid.

[0136] For example, the axial groove is a strip-shaped groove that axially penetrates the sliding fit section; or it is a spiral-shaped groove that axially penetrates the sliding fit section. The presence of the spiral groove allows the flushing fluid to flow through it and form a hydraulic bearing between the bearing component and the drive shaft 2. Due to the radial thrust of the flushing fluid, a more stable gap can be formed between the drive shaft 2 and the bearing component, and the rotation of the drive shaft is more stable.

[0137] It is understandable that flushing fluid can pass through the gap between the bearing and drive shaft 2 without the axial groove. Adding the axial groove allows the flushing fluid to pass through the bearing more effectively.

[0138] This application embodiment also provides a drive shaft. In addition to the first drive shaft described above, the drive shaft 2 includes a second drive shaft. The second drive shaft is a flexible shaft, and the first drive shaft is a rigid shaft. The second drive shaft is connected to the proximal end of the first drive shaft, and the entire outer surface of the second drive shaft is provided with a flexible shaft protective layer. For catheter pumps, the drive shaft needs to pass through the body of the patient undergoing vascular intervention to deliver the pump head to a designated location in the heart. This means that the drive shaft needs to bend in the blood vessel, so part of the drive shaft needs to be a flexible shaft. During the rotation of the entire drive shaft, not only will the rigid shaft experience frictional rotation with the bearing components, but the flexible shaft will also experience frictional rotation with the inner wall of the catheter of the catheter pump. Therefore, a protective layer can also be provided on the flexible shaft to further reduce the damage to the shaft and / or the inner wall of the catheter caused by frictional rotation. The following is a description of the provision of a flexible shaft protective layer on the flexible shaft portion.

[0139] Alternatively, in one possible embodiment, the flexible shaft is connected to the free end of the proximal segment 211.

[0140] In one possible embodiment, at least two layers of braided flexible shaft are used. The distal end of the flexible shaft is connected to a rigid stainless steel shaft (first drive shaft), and the proximal end is connected to the drive shaft of a drive motor. This connects the external drive motor to the internal blood pump head, allowing the shaft to bend over an arc, pass through the aorta, and enter the left ventricle, remotely driving the pump head to transmit a certain torque. The outer layer of the second drive shaft is supported by multiple layers of braided catheters. When the flexible shaft rotates, it contacts the inner layer of the braided catheters. However, this presents the following problems: the outer spiral structure of the flexible shaft may experience wear during contact and rotation; simultaneously, the braided fibers of the flexible shaft rub against each other during axial stretching / compression, generating abrasive debris. This problem arises because the friction between the flexible shaft and the braided catheter is too high; and the braided fiber material has insufficient wear resistance under conditions of fretting wear between fibers.

[0141] This application provides a flexible shaft protective layer on the outer surface of at least one section of the second drive shaft, wherein at least one section refers to at least one section where rotational friction occurs between the second drive shaft and the conduit of the conduit pump. The flexible shaft protective layer can reduce the roughness of the outer surface of the flexible shaft.

[0142] After setting the flexible shaft protective layer, the roughness of the outer surface of the flexible shaft can be optimized, and the friction coefficient between the outer surface of the flexible shaft and the inner tube of the braided guide tube can be reduced when the flushing fluid is used as an intermediate lubricant.

[0143] In theory, it is only necessary to coat the part of the flexible shaft that contacts the inner tube of the braided guide tube with a flexible shaft protective layer. However, since the contact position between the two is not fixed during use, and in order to reduce the processing difficulty, in one possible embodiment, the flexible shaft protective layer can be set on the entire surface of the flexible shaft, thus facilitating the processing to form the flexible shaft protective layer.

[0144] Alternatively, the coating method for the flexible shaft protective layer can be to directly coat the outer surface of the braided flexible shaft with the protective layer, or to coat the flexible shaft protective layer on the braided yarn in advance.

[0145] Optionally, in one possible embodiment, the second drive shaft includes a braided flexible shaft, which includes braided yarns, the outer surface of which is pre-coated with a flexible shaft protective layer before braiding.

[0146] The braided flexible shaft consists of multiple braided layers. The outermost layer of braided yarns in the multiple braided layers is pre-coated with a flexible shaft protective layer before braiding, or each layer of braided yarns in the multiple braided layers is pre-coated with a flexible shaft protective layer before braiding.

[0147] Understandably, if it is only necessary to reduce the roughness of the outer surface of the flexible shaft, then it is only necessary to pre-coat the outermost braid of the multi-layer braided yarn with a flexible shaft protective layer before braiding, or to directly coat the outer surface of the braided flexible shaft with a flexible shaft protective layer, thereby reducing the coefficient of friction between the outer surface of the flexible shaft and the inner tube of the guide tube.

[0148] To enhance the wear resistance between the braided strands in the entire flexible shaft structure, each layer of braided strands is pre-coated with a flexible shaft protective layer before weaving.

[0149] Optionally, in one possible embodiment, the flexible shaft protective layer is a DLC coating or a polymer coating; the polymer coating material can be polytetrafluoroethylene (PTFE).

[0150] In one possible embodiment, the catheter pump includes the drive shaft 2 of the catheter pump in Embodiment 1, and also includes a drive assembly 20 and a catheter 30.

[0151] The distal end of the drive assembly 20 is connected to the proximal end of the conduit 30, and the distal end of the conduit 30 is connected to the proximal end of the pump casing 1. The drive assembly 20 transmits rotational power to the pump casing 1 through the drive shaft 2, thereby driving the impeller 3 inside the pump casing 1 to rotate.

[0152] The flexible shaft passes through the guide tube 30. The proximal end of the flexible shaft is connected to the drive shaft at the distal end of the rigid shaft, and the distal end of the flexible shaft is connected to the proximal section 211 of the rigid shaft. The drive assembly 20 transmits rotational power to the rigid shaft via the drive shaft, thereby driving the impeller 3 to rotate.

[0153] The conduit pump provided in this embodiment includes the pump head assembly 10 of Embodiment 1.

[0154] In the drive shaft 2 of the pump head assembly 10 described above, a protective layer is provided on the support section 21 to cooperate with the bearing component of the pump housing 1 of the duct pump. When the drive shaft 2 moves axially relative to the bearing component, the bearing component is always in contact with the protective layer, thereby preventing the bearing component from causing wear to the drive shaft.

[0155] In one possible embodiment, the pump head assembly has a folded configuration and an extended configuration; it also includes a folded sheath, under the folding force of the folded sheath, the pump head assembly is compressed into the folded configuration; when the pump head assembly is removed from the folded sheath, the pump head assembly gradually returns to the extended configuration.

[0156] This configuration offers advantages in the interventional use of catheter pumps. The pump head assembly 10 and the tip portion of the catheter 30 are inserted into and held within the patient's body; therefore, the peripheral dimensions of the pump head assembly 10 and the catheter 30 should be as small as possible. Smaller pump head assembly 10 and catheter 30 mean that they can be inserted into the patient's body through a smaller puncture site, reducing patient discomfort during the interventional procedure and minimizing complications caused by excessively large puncture sites. In one possible embodiment, the pump head assembly 10 is folded in a retractable configuration, thus occupying the smallest possible peripheral dimension; this retractable configuration corresponds to the interventional procedure of the catheter pump. In an extended configuration, the pump head assembly 10 returns from the retractable configuration to the extended configuration, which corresponds to the operating state of the catheter pump in which the blood pumping fluid channel of the pump head assembly 10 is unobstructed and suitable for pumping blood.

[0157] The drive shaft of the duct pump proposed in this application has a protective layer on the support section that mates with the bearing components of the pump housing. When the first drive shaft moves axially relative to the bearing components, the bearing components are always in contact with the protective layer, thereby reducing or avoiding wear on the first drive shaft caused by the bearing components and reducing or avoiding the generation of particulate matter on the first drive shaft.

[0158] The pump head assembly of the duct pump proposed in this application includes the aforementioned drive shaft. A protective layer is provided on the support section of the drive shaft to mate with the bearing component of the pump housing of the duct pump. When the first drive shaft moves axially relative to the bearing component, the bearing component is always in contact with the protective layer, thereby reducing or avoiding wear caused by the bearing component on the first drive shaft and reducing or avoiding the generation of particulate matter on the first drive shaft.

[0159] The duct pump proposed in this application includes the pump head assembly of the aforementioned duct pump. A protective layer is provided on the support section of the drive shaft of the aforementioned pump head assembly, which mates with the bearing component of the pump housing of the duct pump. When the first drive shaft moves axially relative to the bearing component, the bearing component is always in contact with the protective layer, thereby reducing or avoiding wear on the first drive shaft caused by the bearing component, and reducing or avoiding the generation of particulate matter on the first drive shaft.

Claims

1. A drive shaft for a duct pump, comprising: The first drive shaft includes a support section (21) and an impeller mounting section (22); The first drive shaft is configured to pass through the pump casing (1) of the duct pump, and the impeller (3) inside the pump casing (1) is fixed to the impeller mounting section (22); The support section (21) is configured to pass through a bearing member inside the pump housing (1), and the bearing member is configured to rotatably support the support section (21) to rotate, so that the support section (21) can rotatably support the first drive shaft inside the pump housing (1); The first drive shaft is configured to drive the impeller (3) to rotate so as to pump blood from the blood inlet of the pump housing (1) into the pump housing (1) and pump it out from the blood outlet of the pump housing (1); The first drive shaft is axially sliding relative to the bearing component, and the support section (21) includes a sliding fit section with a protective layer, the hardness of which is greater than the hardness of the first drive shaft; When the first drive shaft slides axially to the distal side relative to the bearing member to the first limit position, the proximal position of the sliding fit section is located near the proximal end face of the bearing member, or is coplanar with the proximal end face; When the first drive shaft slides axially to the second limit position relative to the bearing member, the distal end of the sliding fit section is located on the far side of the distal end face of the bearing member, or is coplanar with the distal end face.

2. The drive shaft of the duct pump according to claim 1, wherein, The bearing component includes a proximal bearing component (4) located near the pump housing (1), and the support section (21) includes a proximal section (211) located near the impeller mounting section (22). The proximal segment (211) is configured to pass through the proximal bearing member (4), and the proximal bearing member (4) is configured to rotatably support the rotation of the proximal segment (211); The proximal section (211) includes a proximal bearing mating section having the protective layer, and the sliding mating section includes the proximal bearing mating section; When the first drive shaft slides axially to the distal side relative to the proximal bearing member (4) to the first limit position, the proximal position of the proximal bearing mating section is located on the proximal side of the proximal end face of the proximal bearing member (4), or is coplanar with the proximal end face of the proximal bearing member (4); When the first drive shaft slides axially to the second limit position relative to the proximal bearing member (4), the distal position of the proximal bearing mating section is located on the far side of the distal end face of the proximal bearing member (4), or is coplanar with the distal end face of the proximal bearing member (4).

3. The drive shaft of the duct pump according to claim 2, wherein, The pump housing (1) is provided with a stop member, which is configured to abut against the bearing member or the first drive shaft to restrict the axial sliding of the first drive shaft; the stop member includes a first stop member (14) fixedly sleeved on the outer periphery of the first drive shaft, the first stop member (14) is located on the proximal side of the proximal bearing member (4) and is configured to restrict the axial sliding of the first drive shaft; The proximal end of the bearing mating section is located at the junction of the first drive shaft and the first stop (14).

4. The drive shaft of the duct pump according to claim 2 or 3, wherein, When the first drive shaft slides axially to the second limit position relative to the proximal bearing member (4), the distal position of the proximal bearing mating section extends 1mm-5mm beyond the distal end face of the proximal bearing member (4).

5. The drive shaft of the conduit pump according to any one of claims 1 to 4, wherein, The bearing component includes a distal bearing component (5) located on the far side of the pump housing (1), and the support section (21) includes a distal section (212) located on the far side of the impeller mounting section (22). The distal segment (212) is configured to pass through the distal bearing member (5), and the distal bearing member (5) is configured to rotatably support the rotation of the distal segment (212); The distal segment (212) includes a distal bearing mating segment having the protective layer, and the sliding mating segment includes the distal bearing mating segment; When the first drive shaft slides axially to the first limit position relative to the distal bearing member (5), the proximal position of the distal bearing mating section is located on the proximal side of the proximal end face of the distal bearing member (5), or is coplanar with the proximal end face of the distal bearing member (5). When the first drive shaft slides axially to the proximal side relative to the distal bearing member (5) to the second limit position, the distal end position of the distal bearing mating section is located on the far side of the distal end face of the distal bearing member (5), or is coplanar with the distal end face of the distal bearing member (5).

6. The drive shaft of the duct pump according to claim 5, wherein, The proximal position of the distal bearing mating section is the axial position of the distal end face of the impeller mounting section (22).

7. The drive shaft of the duct pump according to claim 5, wherein, When the first drive shaft slides axially to the first limit position relative to the distal bearing member (5), the proximal position of the distal bearing mating section extends proximally beyond the proximal end face of the distal bearing member (5) by 0.5mm-2.0mm.

8. The drive shaft of the duct pump according to claim 5 or 7, wherein, When the first drive shaft slides axially to the second limit position relative to the distal bearing member (5) to the proximal side, the distal position of the distal bearing mating section extends 0.5mm-2.0mm beyond the distal end face of the distal bearing member (5) to the distal side.

9. The drive shaft of the duct pump according to claim 1, wherein, The pump housing (1) is provided with a stop member, which is configured to abut against the bearing member or the first drive shaft to restrict the axial sliding of the first drive shaft; The end of one end of the sliding fit section is located at the junction of the stop and the first drive shaft. The stop member is provided with the protective layer.

10. The drive shaft of the duct pump according to claim 9, wherein, The stop member includes a first stop member (14) fixedly sleeved on the outer periphery of the first drive shaft, and the bearing member includes a proximal bearing member (4) located near the pump housing (1). The first drive shaft is also disposed through a second stop member (7) inside the pump housing (1). The proximal bearing member (4) is located far from the second stop member (7). The first stop member (14) slides axially between the second stop member (7) and the proximal bearing member (4) to limit the axial sliding of the first drive shaft. When the first stop (14) abuts against the proximal bearing (4), the first drive shaft slides axially to the first limit position relative to the proximal bearing (4) to the distal side. When the first stop (14) abuts against the second stop (7), the first drive shaft slides axially to the second limit position relative to the proximal bearing (4).

11. The drive shaft of the duct pump according to claim 1, wherein, The protective layer is a diamond-like carbon (DLC) coating, a physical vapor deposition (PVD) molybdenum disulfide coating, a nitride coating, or a ceramic coating, and the surface roughness of the protective layer is less than Ra1.

0.

12. The drive shaft of the duct pump according to claim 1 or 11, wherein, The first drive shaft is a hard shaft with a hardness of 200HV-700HV. After the protective layer is applied, the hardness of the sliding mating section is greater than 1800HV.

13. The drive shaft of the duct pump according to claim 1, wherein, The sliding fit section is provided with an axial groove for flushing fluid to pass through the bearing component. The axial groove is formed by slotting the shaft of the sliding fit section or by forming it on the coating structure of the protective layer. When the axial groove is formed by slotting the shaft of the sliding fit section, the protective layer is coated on all or part of the outer peripheral surface of the sliding fit section, and the part of the outer peripheral surface includes the non-groove outer peripheral surface other than the axial groove; When the axial groove is formed on the coating structure of the protective layer, the protective layer includes a plurality of axially continuous coating strips, and an axial groove is formed between the plurality of coating strips to allow flushing fluid to pass through the bearing element.

14. The drive shaft of the duct pump according to claim 13, wherein, The axial groove is either a strip-shaped groove that axially penetrates the sliding fit section, or a spiral-shaped groove that axially penetrates the sliding fit section.

15. The drive shaft of the duct pump according to claim 1 further includes a second drive shaft, the second drive shaft being a flexible shaft, the first drive shaft being a rigid shaft, the second drive shaft being connected to the proximal end of the first drive shaft, and the outer surface of the second drive shaft being provided with a flexible shaft protective layer.

16. The drive shaft of the duct pump according to claim 15, wherein, The outer surface of at least one section of the second drive shaft is provided with the flexible shaft protective layer, and the at least one section refers to at least one section in which rotational friction occurs between the second drive shaft and the conduit of the conduit pump.

17. The drive shaft of the duct pump according to claim 16, wherein, The second drive shaft includes a braided flexible shaft, which includes braided yarns, the outer surface of which is pre-coated with a flexible shaft protective layer before braiding.

18. The drive shaft of the duct pump according to claim 17, wherein, The braided flexible shaft comprises multiple braided layers. The outermost layer of the braided yarns of the multiple braided layers is pre-coated with the flexible shaft protective layer before braiding, or each layer of the braided yarns of the multiple braided layers is pre-coated with the flexible shaft protective layer before braiding.

19. A pump head assembly for a duct pump, comprising: Pump housing (1) has a blood inlet and a blood outlet; The drive shaft of the duct pump as described in any one of claims 1-18; An impeller (3) is located inside the pump housing (1) and is mounted on the impeller mounting section (22) of the drive shaft (2). The drive shaft (2) drives the impeller (3) to rotate so as to pump blood from the blood inlet into the pump housing (1) and pump it out from the blood outlet.

20. A conduit pump, comprising a drive shaft, a drive assembly (20), and a conduit (30) as described in any one of claims 1-18; The distal end of the drive assembly (20) is connected to the proximal end of the conduit (30), and the distal end of the conduit (30) is connected to the proximal end of the pump housing (1). The drive assembly (20) transmits rotational power to the pump housing (1) through the drive shaft (2), thereby driving the impeller (3) inside the pump housing (1) to rotate.

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