Eccentric rotary grinding head, its manufacturing method, drive shaft and interventional medical device

Abstract

The present invention provides an eccentric atherectomy head for an interventional medical device, a manufacturing method thereof, a drive shaft, and an interventional medical device. The eccentric atherectomy head has a connection hole for connecting to a flexible shaft. The eccentric atherectomy head includes an eccentric base and an abrasive layer on its outer side. The side surface of the eccentric base includes a first curved surface, a second curved surface, and a third curved surface, and the third curved surface is at least a portion of a cylindrical surface. The first curved surface and the second curved surface are symmetrical about the central plane of the eccentric base. The first curved surface and the second curved surface are respectively portions of a convex curved surface formed by rotating a convex curve around the central axis of the connection hole. The distance from each point on the convex curve to the central axis gradually increases along the direction from the end face of the eccentric base to the central plane. The two curved surfaces are partially connected at the central plane of the eccentric base, forming at least one continuous and smooth generatrix on its side surface. The present invention can not only make the eccentric atherectomy head applicable to a wider range of blood vessels, but also improve the controllability and safety of the operation.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to an eccentric grinding head and a manufacturing method thereof, a drive shaft and an interventional medical device. Background Art

[0002] Ischemic heart disease is becoming one of the most lethal diseases, primarily due to atherosclerosis: fat, fiber, and calcium deposit on blood vessel walls, forming plaques that obstruct normal blood flow and lead to vascular obstruction. Existing technologies often utilize interventional balloons and stents to push atherosclerotic plaques into the vessel wall, thereby unclogging the blood vessels and treating ischemic heart disease and peripheral arterial disease. However, for severely calcified lesions, and lesions in specific locations, such as joints, the balloons and stents cannot fully expand within the calcified vessels due to the narrow internal space, making it difficult to achieve the desired therapeutic effect. Therefore, existing technologies have proposed a clinical approach to remove severely calcified plaques using rotational atherectomy. This technique can be performed using an interventional medical device. This device extends into the blood vessel through a flexible shaft equipped with a atherectomy head. By driving the flexible shaft to rotate, the atherectomy head rotates, grinding away the plaque and increasing the effective space in the blood vessel.

[0003] Some existing interventional medical devices utilize eccentric atherectomy heads, such as those disclosed in CN108882947A and CN105658159A, to increase their diameter expansion capabilities. However, these eccentric atherectomy heads, when used during atherectomy, have a relatively large contact area with the vessel wall, resulting in excessive removal force and a strong removal effect. This hinders control of the atherectomy process, increases surgical risk, and reduces surgical safety. Summary of the Invention

[0004] Based on the above situation, the main purpose of the present invention is to provide an eccentric grinding head and its manufacturing method, drive shaft and interventional medical device to solve the technical problem of excessive surgical risks in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A first aspect of the present invention provides an eccentric atherectomy head for an interventional medical device, the eccentric atherectomy head having a connection hole for connecting to a flexible shaft; the eccentric atherectomy head comprises an eccentric base and an abrasive layer, the side surface of the eccentric base comprising a first curved surface, a second curved surface, and a third curved surface.

[0007] The first curved surface and the second curved surface respectively cover at least two ends of the eccentric base and are symmetrical about a center plane between the two ends of the eccentric base. The two are respectively parts of the same revolution curved surface, and the revolution curved surface is formed by rotating a smooth convex curve around a central axis. The central axis is the axis of the connecting hole, and the distance from each point on the convex curve to the central axis gradually increases along the direction from the end surface of the eccentric base to the center plane;

[0008] The third curved surface is at least a portion of a cylindrical surface, located in the middle section of the eccentric base, and its rotation axis is the eccentric axis, and the eccentric axis is parallel to the central axis of the connecting hole and has a distance therebetween;

[0009] wherein the first curved surface and the second curved surface are partially connected at the center plane, forming at least one continuous and smooth generatrix on the side surface; the revolution curved surface intersects with the cylindrical surface to form a first intersection line and a second intersection line respectively located on both sides of the center plane; the portion of the revolution curved surface located between the center plane, the first intersection line, and the eccentric base and its end surface on the same side forms the first curved surface, the portion located between the center plane, the second intersection line, and the eccentric base and its end surface on the same side forms the second curved surface, and the portion of the cylindrical surface located between the first intersection line and the second intersection line forms the third curved surface;

[0010] The abrasive layer is arranged on the side surface of the eccentric base.

[0011] Preferably, the first curved surface, the second curved surface and the third curved surface intersect at one point on the central plane.

[0012] Preferably, the first curved surface and the second curved surface are connected in a partial area in the circumferential direction of the eccentric base, and the first intersection line and the second intersection line are connected at the center plane and transition smoothly.

[0013] Preferably, the convex curve is a circular arc, an elliptical arc, a parabola or a hyperbola.

[0014] Preferably, the convex curve is an arc line, and the radius R of the convex curve, the axial length L of the eccentric base, the maximum radial dimension D of the eccentric base, the diameter d of the connecting hole, the eccentric distance M between the eccentric axis and the central axis, and the minimum wall thickness s of the eccentric base satisfy the following formula:

[0015] R=[L 2 / 4+(D / 2+d / 2-M+s) 2 ] / [2*(D / 2+d / 2-M+s)].

[0016] Preferably, the eccentricity between the eccentric axis and the central axis is 0.05 mm to 0.6 mm; the maximum radial dimension of the eccentric base is 1.0 to 2.5 mm;

[0017] Preferably, the axial dimension of the eccentric base is 1.0 mm to 7.0 mm; and the minimum wall thickness of the eccentric base is greater than or equal to 0.05 mm.

[0018] Preferably, the protruding height of the abrasive grains in the abrasive grain layer is 5 to 35 μm.

[0019] A second aspect of the present invention provides a drive shaft for an interventional medical device, comprising a flexible shaft and any one of the above-mentioned eccentric atherectomy heads, wherein the eccentric atherectomy head is disposed in a distal region of the flexible shaft, and the connecting hole is plug-connected to the flexible shaft.

[0020] Preferably, in the distal region, the flexible shaft is provided with a plurality of eccentric atherectomy heads at intervals along its axial direction, the eccentric directions of the eccentric atherectomy heads are staggered in the circumferential direction of the flexible shaft, and the radial maximum dimension of the eccentric atherectomy heads in the middle portion is greater than the radial maximum dimension of the eccentric atherectomy heads at the two end portions.

[0021] Preferably, along the axial direction of the flexible shaft, the maximum radial dimensions of the plurality of eccentric grinding heads gradually decrease from the middle to both ends.

[0022] A third aspect of the present invention provides an interventional medical device comprising any one of the drive shafts described above.

[0023] A fourth aspect of the present invention provides a method for manufacturing an eccentric atherectomy head for an interventional medical device, comprising the steps of:

[0024] S100: manufacturing an eccentric base, wherein the side surface of the eccentric base includes a first curved surface, a second curved surface and a third curved surface,

[0025] The first curved surface and the second curved surface respectively cover at least two ends of the eccentric base and are symmetrical about a center plane between the two ends of the eccentric base. The two are respectively parts of the same revolution curved surface, and the revolution curved surface is formed by rotating a smooth convex curve around a central axis. The central axis is the axis of the connecting hole, and the distance from each point on the convex curve to the central axis gradually increases along the direction from the end surface of the eccentric base to the center plane;

[0026] The third curved surface is at least a portion of a cylindrical surface, located in the middle section of the eccentric base, and its rotation axis is the eccentric axis, and the eccentric axis is parallel to the central axis of the connecting hole and has a distance therebetween;

[0027] wherein the first curved surface and the second curved surface are partially connected at the center plane, forming at least one continuous and smooth generatrix on the side surface; the revolution curved surface intersects with the cylindrical surface to form a first intersection line and a second intersection line respectively located on both sides of the center plane; the portion of the revolution curved surface located between the center plane, the first intersection line, and the eccentric base and its end surface on the same side forms the first curved surface, the portion located between the center plane, the second intersection line, and the eccentric base and its end surface on the same side forms the second curved surface, and the portion of the cylindrical surface located between the first intersection line and the second intersection line forms the third curved surface;

[0028] The abrasive layer is arranged on the side surface of the eccentric base.

[0029] S200: forming an abrasive layer on the side of the eccentric base to obtain an eccentric grinding head.

[0030] According to a third aspect of the present invention, the abrasive layer is formed on the side surface of the eccentric substrate by nickel plating or brazing.

[0031] Beneficial effects

[0032] The eccentric atherectomy head of the present invention is provided with an entire atherectomy surface comprising three curved surfaces, and the two curved surfaces covering the two ends are formed by rotating around different axes of rotation with the other curved surface respectively. The curved surfaces covering the two ends are at least partially connected to the other curved surface while being connected to each other respectively, so that there is at least one continuous and smooth generatrix on the entire atherectomy surface. When the eccentric atherectomy head is applied to interventional medical equipment, as the flexible shaft rotates at high speed, the eccentric atherectomy head forms line contact with the blood vessel wall only when it contacts the third curved surface, while the contact with the blood vessel wall in other areas is point contact, especially when the position on the atherectomy surface farthest from the central axis is in point contact with the blood vessel wall. Therefore, by controlling the proportion of the first curved surface, the second curved surface and the third curved surface in the entire atherectomy surface, the area of point contact and line contact of the eccentric atherectomy head during atherectomy can be better controlled, thereby controlling the removal of intravascular plaque. The efficiency and grinding ability are improved, so as to better achieve the treatment of vascular lesions at different diameters and positions, avoid the damage to the blood vessel wall caused by continuous line contact, and the continuous large impact force caused by continuous line contact, and reduce the grinding amount when the eccentric atherectomy head contacts the blood vessel wall at each position, thereby greatly reducing the impact of the eccentric atherectomy head on the blood vessel wall during atherectomy, making the entire atherectomy process relatively smooth, and improving the safety of the operation; at the same time, since both ends of the entire atherectomy surface are convex smooth curved surfaces, gaps can be formed between these curved surfaces and most positions of the blood vessel wall in the axial direction, and the grinding chips generated at the moment of point contact are relatively small, so the grinding chips generated by atherectomy can also be well discharged from the gap between the curved surface and the blood vessel wall as soon as possible, and there will basically be no jamming or even blood vessel blockage caused by untimely discharge of grinding chips, further improving the safety of the operation.

[0033] Other beneficial effects of the present invention will be explained through the introduction of specific technical features and technical solutions in the specific implementation methods. Those skilled in the art should be able to understand the beneficial technical effects brought about by the introduction of these technical features and technical solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[0035] Figure 1 A schematic structural diagram of a preferred embodiment of the eccentric atherectomy head provided by the present invention;

[0036] Figure 2 for Figure 1 A schematic longitudinal section of an eccentric atherectomy head is shown;

[0037] Figure 3 A schematic structural diagram of another preferred embodiment of the eccentric atherectomy head provided by the present invention;

[0038] Figure 4 for Figure 3 A schematic longitudinal section of an eccentric atherectomy head is shown;

[0039] Figure 5 A schematic structural diagram of a preferred embodiment of the drive shaft provided by the present invention;

[0040] Figure 6 A schematic structural diagram of another preferred embodiment of the drive shaft provided by the present invention.

[0041] In the picture:

[0042] 100, eccentric atherectomy head; 10, connecting hole; 11, central axis; 20, first curved surface; 21, first curve; 22, first phase connection; 30, third curved surface; 31, eccentric axis; 32, straight line; 40, second curved surface; 41, second curve; 42, second phase connection; 50, convex curve; 60, central plane;

[0043] 200. Flexible shaft. DETAILED DESCRIPTION

[0044] The present invention is described below based on the following embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail. In order to avoid obscuring the essence of the present invention, well-known methods, processes, procedures, and components are not described in detail.

[0045] Furthermore, persons of ordinary skill in the art will appreciate that the figures provided herein are for illustration purposes only and are not necessarily drawn to scale.

[0046] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include," "comprising," and similar words should be construed in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to."

[0047] In the description of the present invention, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0048] It should be noted that, in the description of the present invention, "far" and "near" are relative to the operator of the interventional device. The proximal end refers to the end close to the operator, and the distal end refers to the end away from the operator. That is, for the same component, if it is only partially inserted into the patient's body, the end inserted into the patient's body is the distal end, and the end located outside the body close to the operator is the proximal end.

[0049] The present invention provides an interventional medical device that can be used to treat cardiovascular diseases and perform atherosclerosis resection. The interventional medical device includes a drive shaft, such as Figure 5 、 Figure 6 As shown, the drive shaft includes a flexible shaft 200 and an eccentric atherectomy head 100. The eccentric atherectomy head 100 is disposed at the distal end of the flexible shaft 200. Specifically, the eccentric atherectomy head 100 has a connecting hole 10 for connecting to the flexible shaft 200. The connecting hole 10 extends through the entire eccentric atherectomy head 100 along the axial direction of the flexible shaft 200. The flexible shaft 200 is inserted into the connecting hole 10 to fix the eccentric atherectomy head 200 to the flexible shaft 200. The flexible shaft 200 and the eccentric atherectomy head 100 can be connected by bonding, welding, or interference fit. The flexible shaft 200 can be formed by winding multiple strands of spring wire.

[0050] Although eccentric atherectomy heads exist in the prior art, generally, regardless of the type, their atherectomy surfaces are either cylindrical or conical, with the cylindrical or conical surface being eccentrically positioned relative to the connecting hole. However, since blood vessels are generally cylindrical, the circumferential generatrix of such eccentric atherectomy heads, whether cylindrical or conical, is a straight line. Consequently, line contact is formed between the atherectomy surface and the vessel wall. This prolonged line contact, coupled with the high-speed motion of the flexible shaft, creates a significant eccentric force, resulting in a strong removal force and a strong removal effect on the vessel wall tissue. This hinders control over the removal process, creates safety hazards, and increases surgical risk. Furthermore, the intersection of the conical and cylindrical surfaces is sharp, making it easy for the eccentric atherectomy head to cut the vessel at this intersection when the head changes position, further increasing surgical risk.

[0051] In order to solve the above problems, the eccentric atherectomy head 100 of the present invention adopts an atherectomy surface that combines a convex smooth curved surface with a cylindrical surface, and the entire atherectomy surface has at least one continuous and smooth generatrix. Specifically, referring to Figure 1-Figure 4 The eccentric grinding head 100 includes an eccentric base and an abrasive layer (not shown). The connecting hole 10 is provided on the eccentric base. The eccentric base includes side faces and end faces. The end faces refer to the two faces of the eccentric base that are opposite to each other along the central axis 11 of the connecting hole 10. The side faces are arranged around the central axis 11 of the connecting hole 10, but are not limited to being formed by rotating around the central axis 11. The side faces of the eccentric base include a first curved surface 20, a second curved surface 40, and a third curved surface 30. The third curved surface 30 is at least a portion of a cylindrical surface located in the middle section of the eccentric base. Its rotation axis is the eccentric axis 31. The eccentric axis 31 is parallel to the central axis 11 of the connecting hole 10 and is separated by a distance, which can be recorded as the eccentric distance M.

[0052] The first curved surface 20 and the second curved surface 40 are both smooth convex curved surfaces, each covering at least the two ends of the eccentric base. The first curved surface 20 and the second curved surface 40 are symmetrical about a central plane 60 between the two ends of the eccentric base. They are both portions of the same surface of revolution, formed by a smooth convex curve 50 rotating about the central axis 11. The convex curve 50 is symmetrical about the central plane 60, and the distance from each point on the convex curve 50 to the central axis 11 gradually increases from the end face of the eccentric base to the central plane 60. In other words, the convex curve 50 protrudes away from the central axis 11, with its maximum protrusion located at the central plane 60. The first curved surface 20 and the second curved surface 40 partially meet at the central plane 60, forming at least one continuous, smooth generatrix on the side of the eccentric base. The intersection of the curved surface of revolution and the cylindrical surface forms a first intersection line (see first intersection line 22 in the accompanying drawings, which is a portion of the first intersection line) and a second intersection line (see second intersection line 42 in the accompanying drawings, which is a portion of the second intersection line) located on either side of the center plane 60. The portion of the curved surface of revolution located between the center plane 60, the first intersection line, and the eccentric base and its ipsilateral end face forms the first curved surface 20. The portion located between the center plane 60, the second intersection line, and the eccentric base and its ipsilateral end face forms the second curved surface 40. The portion of the cylindrical surface located between the first and second intersection lines forms the third curved surface 30. In other words, the intersection line between the first curved surface 20 and the third curved surface 30 is at least part of the first intersection line, and the intersection line between the second curved surface 40 and the third curved surface is at least part of the second intersection line. An abrasive layer is disposed on the side of the eccentric base, i.e., the abrasive layer is disposed on the side of the eccentric base so that the abrasive particles are evenly distributed across the entire side face, thereby forming the abrasive surface of the eccentric atherectomy head (i.e., the surface formed by the abrasive layer).

[0053] For the convenience of the following description, the two ends of the eccentric base can be respectively referred to as the first end and the second end, the first curved surface 20 covers at least the first end, the second curved surface 40 covers at least the second end, the first curved surface 20 extends from the first end to the center plane 60 to cover the rest of the eccentric base, and the second curved surface 40 extends from the second end to the center plane 60 to cover the rest of the eccentric base, and the two curved surfaces will be connected at the center plane 60, and the connected portion can be only one point (such as Figure 1 As shown), it can also cover the side along its circumferential part (as shown Figure 3Specifically, the first curved surface 20 is the area enclosed by the end face of the first end of the convex curved surface, the center plane 60, and the first intersection line. The second curved surface 40 is the area enclosed by the end face of the second end of the convex curved surface, the center plane 60, and the second intersection line. The side surface of the eccentric base can be considered to be formed by the intersection of a convex curved surface formed by the rotation of the convex curve 50 about the center axis 11 and a cylindrical surface. The portion of the formed intersection line located on the side of the center plane 60 near the first end is the first intersection line, and the portion located on the side of the center plane 60 near the second end is the second intersection line. However, in the side surface of the eccentric base, convex curved surfaces are selected on the side of the first intersection line near the first end, the side of the second intersection line near the second end, and the side of the first and second intersection lines near the maximum eccentricity, and a cylindrical surface is selected between the first and second intersection lines.

[0054] That is, the side of the eccentric base is formed by connecting three surfaces of revolution. The generatrix of the first curved surface 20 and the second curved surface 40 is a curve, namely the first curve 21 and the second curve 41. The axis of revolution of the first curved surface 20 and the second curved surface 40 is the same, which is the center axis 11 of the connecting hole 10. The generatrix of the third curved surface 30 is a straight line. The axis of revolution of the third curved surface 30 is eccentric with respect to the center axis 11, which is the eccentric axis 31. The center of gravity of the entire eccentric base formed in this way will deviate from the center line 11. In the longitudinal section of the eccentric base at the maximum eccentricity C, as shown Figure 2 、 Figure 4 As shown, the generatrix on the eccentric base at least at the maximum eccentricity point C is a continuous smooth curve, and on the side where the maximum eccentricity point C is located, that is, Figure 2On the upper side, the first curve 21, the second curve 41, and the eccentric axis 31 are located on the same side of the central axis 11. The first curve 21 and the second curve 41 are symmetrically arranged about the central plane 60. They are respectively two segments on the convex curve 50. However, at some positions along the circumferential direction of the side surface, the two curves are connected (i.e., the convex curve 50), and at other positions along the circumferential direction of the side surface, the two curves are separated, i.e., the two curves are two discontinuous segments on the convex curve 50. The first curve 21 is a smooth curve that convexly extends away from the central axis 11. The first end of the first curve 21 is closer to the central axis 11 than the other end. Specifically, the distance from each point on the first curve 21 to the central axis 11 gradually increases from the end closest to the first end to the other end, thereby forming the formed first curved surface 20 as a convex, smooth curved surface. Because the first curve 21 and the second curve 41 are symmetrical about the central plane, the second curve 41 is also a convex, smooth curve. The second end is closer to the central axis 11 than the other end, and the distance from each point on the second curve 41 to the central axis 11 gradually increases from the second end to the other end. As a result, the radial dimensions of the outer contour of the eccentric base body's side surface (in the axial direction) at the two ends are smaller than those of the central portion. After the abrasive layer is formed on the side surface, the abrasive surface of the entire eccentric abrasive head is larger in the middle and smaller at the two ends.

[0055] The above-mentioned center plane is perpendicular to the center axis 11, that is, the center plane refers to the plane passing through the center of the eccentric base along its axial direction and perpendicular to the center axis 11. The maximum eccentricity point C of the eccentric base refers to the position of the point on the side of the eccentric base with the maximum distance from the center axis. When there is only one point at this position, it is located on the center plane (such as Figure 2 、 Figure 4 As shown), this position can be recorded as the maximum eccentric position, the longitudinal section passing through this position refers to the section passing through the maximum eccentric position and the central axis 11 at the same time, and the maximum eccentric side refers to the side where the maximum eccentricity C is located.

[0056] During operation, the eccentric atherectomy head 100 of the aforementioned embodiment not only rotates with the rotation of the flexible shaft 200 but also revolves in orbit due to its eccentric mass, thereby achieving a diameter-expanding and abrading effect on the vessel wall. Specifically, using an eccentric atherectomy head 100 with a smaller outer diameter can increase the inner diameter of the vessel wall to a larger diameter through atherectomy, thereby achieving a larger diameter expansion. Experimental studies have shown that when the eccentric atherectomy head 100 of the present invention has a maximum radial dimension of 1.0 mm and the flexible shaft 200 rotates at 170,000 rpm, atherectomy of a vessel with an inner diameter (referring to the inner diameter of the plaque formation) substantially equal to the maximum radial dimension is performed. After 120 seconds of atherectomy, the resulting diameter expansion reaches over 1.5 mm, and can typically reach 1.6 mm. This demonstrates excellent atherectomy efficiency and diameter expansion capacity, while also minimizing impact force on the vessel.

[0057] In the present invention, the ablation surface of the eccentric atherectomy head 100 includes three convex rotational curved surfaces, and the first curved surface 20 and the second curved surface 40 are partially connected at the center plane. There is at least one continuous and smooth generatrix on the side surface of the eccentric base, and at most the middle section includes a third curved surface 30. Both sides are convex curved surfaces, so that the entire eccentric atherectomy head 100 forms a structure with small ends and large middle in the axial direction. In this way, the eccentric atherectomy head of the present invention has a smaller eccentric mass and a smaller centrifugal force than other eccentric structures when the geometric eccentricity (i.e., the distance from the center of gravity of the eccentric base to the axis of the flexible shaft) is the same. Therefore, the grinding force generated is smaller, and the entire ablation surface is smoother. When the position of the eccentric atherectomy head changes, it basically does not produce a cutting effect on the blood vessel. When the flexible shaft rotates at high speed, the eccentric atherectomy head 100 forms a linear contact only when the third curved surface 30 contacts the blood vessel wall, while the other When the area contacts the blood vessel wall, it is point contact. Therefore, by controlling the proportion of the first curved surface 20, the second curved surface 40 and the third curved surface 30 in the entire atherectomy surface, the area of point contact and line contact of the eccentric atherectomy head during atherectomy can be better controlled, the efficiency and grinding ability of plaque removal in the blood vessel can be controlled, and thus the treatment of vascular lesions at different diameters and positions can be better achieved; and during the entire atherectomy process, the eccentric atherectomy head will not be in line contact with the blood vessel wall all the time, and even at the maximum eccentricity, it is point contact, thereby avoiding damage to the blood vessel wall caused by continuous line contact between the eccentric atherectomy head 100 and the blood vessel wall; and because the contact area between the eccentric atherectomy head 100 and the blood vessel wall is reduced, the amount of grinding when each position of the eccentric atherectomy head 100 contacts the blood vessel wall is also reduced, which can also greatly reduce the impact of the eccentric atherectomy head 100 on the blood vessel wall during atherectomy, making the entire atherectomy process relatively smooth and improving the safety of the operation.

[0058] At the same time, in the present invention, since both end portions of the entire atherectomy surface are convex curved surfaces, forming a structure that is larger in the middle and smaller at both ends, during the atherectomy process, a gap is formed between the portions of the two curved surfaces that are not in contact with the blood vessel wall in the axial direction. In addition, the instantaneous atherectomy amount is small, and the instantaneous grinding debris generated is relatively small. Therefore, the grinding debris generated by the atherectomy can be well discharged from the gap between the curved surface and the blood vessel wall as soon as possible, and there is basically no jamming or even blood vessel blockage caused by untimely discharge of grinding debris, thereby further improving the safety of the operation.

[0059] In the eccentric atherectomy head 100 of the present invention, the distance between the eccentric axis 31 and the central axis 11, i.e., the eccentricity M, can be 0.05 mm to 0.6 mm, such as 0.05 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or 0.6 mm. A larger distance increases the inner diameter of the blood vessel after atherectomy. This range allows for better control of the eccentricity of the atherectomy head, and thus the grinding force during the atherectomy process, thereby improving grinding efficiency while preventing damage to the blood vessel wall caused by excessive grinding force.

[0060] By adopting the structure of the above-mentioned eccentric atherectomy head 100, it is possible to ensure the eccentricity and the atherectomy effect while making the maximum radial dimension D of the eccentric base 100 be 1.0 mm to 2.5 mm, such as 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, or 2.5 mm. It can be seen that the eccentric atherectomy head 100 of the present invention can be made smaller while ensuring the atherectomy effect. Therefore, it can be applied to relatively thin blood vessels, thereby increasing the scope of application of the eccentric atherectomy head 100.

[0061] Some plaques in blood vessels are relatively long, while others are relatively short. The dimension of the eccentric atherectomy head 100 along the central axis 11, i.e., the axial length L, can be 1.0 mm to 7.0 mm, such as 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.5 mm, 2.8 mm, 3.0 mm, 3.3 mm, 3.6 mm, 3.8 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm, 6.8 mm or 7.0 mm, etc. The larger the dimension, the higher the efficiency of atherectomy. In the present invention, eccentric atherectomy heads 100 of different lengths can be manufactured according to the condition of the lesion (such as the length of the plaque), so that by selecting atherectomy heads of different lengths, both the safety of the operation and the efficiency of atherectomy can be ensured.

[0062] In order to increase the strength of the eccentric atherectomy head 100, the minimum wall thickness s of the eccentric base is greater than or equal to 0.05 mm, such as 0.05 mm, 0.06 mm, 0.08 mm or 0.1 mm, so as to reduce its overall weight while ensuring the strength of the eccentric atherectomy head 100, reduce the impact force on the blood vessel wall, and further improve the safety of the operation.

[0063] The diameter of the connecting hole 10 can be determined based on the flexible shaft 200 it is mating with. The diameter of the connecting hole 10 can be slightly larger than the diameter of the flexible shaft 200, so that the two form a clearance fit, and then are connected by bonding, welding, etc. Alternatively, the diameter of the connecting hole 10 can be slightly smaller than the diameter of the flexible shaft 200, so that the two form an interference fit, that is, the connection between the two is achieved by interference fit. Of course, in this method, the connection strength can also be increased by bonding, welding, etc. The diameter d of the connecting hole 10 can be between 0.55mm and 0.85mm, such as 0.55mm, 0.6mm, 0.65mm, 0.67mm, 0.7mm, 0.75mm, 0.8mm or 0.85mm. Specifically, when used in coronary blood vessels, the diameter of the connecting hole 10 can be selected to be around 0.65mm. When used in peripheral arteries, the diameter of the connecting hole is 0.8mm.

[0064] Specifically, for the eccentric atherectomy head 100, the distance between the eccentric axis 31 and the central axis 11 can be determined through simulation experiments to meet the required grinding force. Then, while meeting this distance range, the maximum radial dimension D of the eccentric base is selected to be the smallest. In this way, the eccentric atherectomy head can be adapted to more blood vessels while ensuring the grinding force, thereby expanding the scope of application of the eccentric atherectomy head. In actual use, the structure of the present invention can be used to manufacture eccentric atherectomy heads 100 with different maximum dimensions D at the same eccentric distance M. It is also possible to manufacture eccentric atherectomy heads with different axial lengths L, and to manufacture different combinations of the first curved surface 20, the third curved surface 30, and the second curved surface 40 (as shown in the attached figure) Figure 1 、 Figure 3 Even other embodiments described in detail below) can be used, or several methods can be combined to manufacture eccentric atherectomy heads of various specifications, so that the optimal eccentric atherectomy head can be selected when used on different blood vessels to achieve the optimal combination of atherectomy effect and surgical safety.

[0065] Among them, the convex curve 50 is preferably a circular arc, an elliptical arc, a parabola or a hyperbola, and accordingly, the first curve 21 and the second curve 41 are circular arcs, elliptical arcs, parabolas or hyperbolas. That is, if each point on the convex curve 50 (or the first curve 21 and the second curve 41) satisfies the circular formula, then the convex curve 50 (or the first curve 21 and the second curve 41) is a circular arc; if it satisfies the elliptical formula, then the convex curve 50 (or the first curve 21 and the second curve 41) is an elliptical arc; if it satisfies the parabola formula, then the convex curve 50 (or the first curve 21 and the second curve 41) is a parabola; if it satisfies the hyperbola formula, then the convex curve 50 (or the first curve 21 and the second curve 41) is a hyperbola, except that the hyperbola is convex outward relative to the central axis 11 (i.e., convex in the direction away from the central axis 11). When the convex curve 50 (or the first and second curves 21 and 41) is a circular arc, the intersection line of the first, second, and third curved surfaces 20, 40, and 30 (i.e., the first and second intersection lines) can be smoother, reducing the impact on blood vessels during atherectomy, while also reducing processing difficulty and increasing the yield rate. When the convex curve 50 (or the first and second curves 21 and 41) is an elliptical arc, parabola, or hyperbola, the intersection line of the first, second, and third curved surfaces 20, 40, and 30 (i.e., the first and second intersection lines) can be smoother, resulting in a better atherectomy effect. Of course, the convex curve 50 can also be other continuous, smooth curves that bulge away from the central axis 11. Of course, the first and second curves 21 and 41 can also be other convex, smooth curves.

[0066] The first phase connection 22 can be a closed curve in the circumferential direction of the eccentric grinding head 100, such as Figure 1 As shown, the first phase connection 22 may not be closed in the circumferential direction of the eccentric grinding head 100, that is, there may be a disconnected area, such as Figure 3 As shown, the first phase connection 22 is broken into two parts at the maximum eccentricity. Of course, when the axial length of the eccentric base is relatively small, the first phase connection 22 may be on the opposite side of the maximum eccentricity (i.e. Figure 3 Similarly, the second phase connection 42 can be a closed curve in the circumferential direction of the eccentric grinding head 100, such as Figure 1 As shown, the second phase connection 42 may not be closed in the circumferential direction of the eccentric grinding head 100, that is, there may be a disconnected area, such as Figure 3 When the first phase connection 22 and the second phase connection 42 are both closed curves in the circumferential direction of the eccentric atherectomy head 100 or are continuous at the maximum eccentricity C, the first phase connection 22 and the second phase connection 42 can intersect at a point at the maximum eccentricity C, or be connected to form a smooth curve, which is a continuous section of the intersection line of the revolution surface and the cylindrical surface.

[0067] In one embodiment, the first curved surface 20, the second curved surface 40 and the third curved surface 30 intersect at a point at the center plane 60, that is, compared to the maximum eccentricity C, as shown in FIG. Figure 1 、 Figure 2 As shown, at the maximum eccentricity C, there is basically no third curved surface 30, and the first curved surface 20 and the second curved surface 40 are connected. The first phase connection 22 and the second phase connection 42 are both continuous, and the two intersect at a point at the maximum eccentricity C. On the longitudinal section through the maximum eccentricity C, as shown Figure 2 As shown, the maximum distance L1 between the first and second curves 21, 41 and the eccentric axis 31 is equal to the radius L2 of the third curved surface 30. In this embodiment, at the maximum eccentricity C, the first and second curves 21, 41 directly connect, forming a convex curve. This forms a single continuous, smooth generatrix on the side of the eccentric body, which is the convex curve 50. In other words, all points on the side at the same circumferential position can be connected to form a line. Of these lines, only the line passing through the maximum eccentricity C is continuous and smooth, forming a complete convex curve. Each of the other lines consists of two intervals between the first and second curves 21, 41, and a straight line connecting the first and second curves 21, 41 (i.e., the cylindrical generatrix), or consists solely of a straight line. With this eccentric atherectomy head, every point on this continuous, smooth generatrix makes point contact with the vessel wall, further reducing the contact area. Linear contact only occurs in other areas with smaller eccentricities. By using this eccentric grinding head 100, the grinding impact force on the maximum eccentric side is significantly reduced. Although the grinding efficiency of plaques is relatively low, the safety is significantly improved. It is particularly suitable for the treatment of plaques in some blood vessels with better safety, such as the grinding of plaques in the limbs or near the heart.

[0068] In another embodiment, the first curved surface 20 and the second curved surface 40 are connected in a partial area in the circumferential direction of the eccentric base, and the first intersection line and the second intersection line are connected at the center plane 60 with a smooth transition. Compared with the first curved surface 20 and the second curved surface 40 being connected at only one point, in this embodiment, the first curved surface 20 and the second curved surface 40 are connected at more locations, and the two continuously form a connected structure along the circumference of the side surface at the center plane 60, that is, near the maximum eccentricity C, there are only the first curved surface 20 and the second curved surface 40, and there is no third curved surface 30 at all. Figure 3 、 Figure 4As shown, near the maximum eccentricity C, the first curved surface 20 (the portion of the center plane 60 close to the first end) and the second curved surface 40 (the portion of the center plane 60 close to the second end) are connected. At this time, the first phase connection 22 and the second phase connection 42 are connected in this area to form a smooth curve (that is, the first intersection line and the second intersection line are connected together), and the first phase connection 22 itself and the second phase connection 42 itself are each disconnected in this area (that is, near the maximum eccentricity C). That is to say, the first intersection line located at the center plane 60 close to the first end is disconnected into two spaced segments at the center plane 60, and the second intersection line located at the center plane 60 close to the second end is also disconnected into two spaced segments at the center plane 60. In this embodiment, in the area where the first curved surface 20 and the second curved surface 40 meet, each first curve 21 is directly connected to the corresponding second curve 41 (i.e., located at the same circumferential position) to form a convex curve 50. In this way, more continuous and smooth generatrixes can be formed on the side of the eccentric base. The generatrix is the convex curve 50. In other words, the points on the side at the same circumferential position can be connected together to form a line. Among these lines, the lines passing through the meeting area are continuous and smooth and are complete convex curves. The other lines each include two intervals of the first curve 21 and the second curve 41, as well as a straight line connecting the first curve 21 and the second curve 41 (i.e., the generatrix of the cylindrical surface), or only include straight lines. In the longitudinal section through the maximum eccentricity C, as shown in FIG. Figure 4 As shown, the maximum distance L1 from the first curve 21 and the second curve 41 to the eccentric axis 31 is less than the radius L2 of the third curved surface 30. This eccentric atherectomy head 100 can form point contact with the blood vessel wall at each position on the maximum eccentric side and its vicinity. For the entire eccentric atherectomy head, there are more positions of point contact with the blood vessel wall, and the grinding impact force on the maximum eccentric side is further reduced. Although the efficiency of atherectomy for plaque is relatively low, the safety is significantly improved. Therefore, this eccentric atherectomy head is suitable for the treatment of plaques in some blood vessels with relatively high safety requirements, such as atherectomy of plaques in blood vessels near the heart.

[0069] Obviously, no matter whether the first curved surface 20 and the second curved surface 40 are connected in a large area or only at one point, no sharp corners are formed at the maximum eccentric side, thereby making the transition between the first curved surface 20, the third curved surface 30 and the second curved surface 40 smoother, thereby improving the efficiency of atherectomy while minimizing the chance of vascular damage and further improving the safety of the operation.

[0070] In each of the above-described embodiments, the overall weight of the eccentric atherectomy head can be determined by controlling the size of L1 relative to L2. A smaller L1 corresponds to more material removed from the cylindrical blank (described below), resulting in a lower weight and a smaller eccentric force generated during rotation. The curvature radius of the first curve 21 and the second curve 41 (or the curvature radius of the convex curve 50) can control the shape of the first curved surface 20 and the second curved surface 40, thereby controlling the force exerted on the vascular wall during atherectomy. The following describes the relationship between various physical quantities in the eccentric atherectomy head 100, using the example of the first curve 21 and the second curve 41 being circular arcs. The radius of the first curve 21 and the second curve 41 (or the convex curve 50) is R. The radius R of the convex curve 50, the axial length L of the eccentric base, the maximum radial dimension D of the eccentric base, the diameter d of the connecting hole 10, the eccentricity M between the eccentric axis 31 and the central axis 11, and the minimum wall thickness s of the eccentric base satisfy the following formula:

[0071] R=[L 2 / 4+(D / 2+d / 2-M+s) 2 ] / [2*(D / 2+d / 2-M+s)].

[0072] It should be noted that, due to different selections of the axial length of the eccentric atherectomy head 100, there may be only the third curved surface 30, but not the first curved surface 20 and the second curved surface 40, on the opposite side of the maximum eccentricity C. Furthermore, although in the present invention, the portion primarily subjected to atherectomy is the portion near the maximum eccentricity of the eccentric atherectomy head 100, particularly for diameter expansion (enlarging the inner diameter of the blood vessel wall), other portions of the eccentric atherectomy head 100 of the present invention, such as the portion opposite the maximum eccentricity C, can also perform atherectomy.

[0073] When the eccentric atherectomy head 100 in the above-mentioned embodiments is applied to a drive shaft, the distal region of the flexible shaft 200 may be provided with only one eccentric atherectomy head 100 or with multiple eccentric atherectomy heads 100. In particular, when the lesion is long, a drive shaft with multiple eccentric atherectomy heads 100 can be used to greatly improve the efficiency of atherectomy.

[0074] Specifically, in an embodiment in which a plurality of eccentric atherectomy heads 100 are arranged at intervals along the axial direction of the flexible shaft 200 at the distal end region of the flexible shaft 200, the eccentric directions of the eccentric atherectomy heads 100 are staggered in the circumferential direction of the flexible shaft 200. That is, if viewed along the axial direction of the flexible shaft 200, the maximum eccentricity C of the eccentric atherectomy heads 100 is distributed along the circumferential direction of the flexible shaft 200. Preferably, the plurality of eccentric atherectomy heads 100 are evenly distributed in the circumferential direction to avoid damage to the blood vessels due to excessive centrifugal force on one side during rotation.

[0075] In embodiments of multiple eccentric atherectomy heads 100, the eccentric atherectomy heads 100 on the same flexible shaft 200 can be identical (including in shape and size) or different. Preferably, along the axial direction of the flexible shaft 200, the maximum radial dimensions of the multiple eccentric atherectomy heads 100 gradually decrease from the center toward the ends. Specifically, the maximum radial dimension of the eccentric atherectomy heads 100 in the middle portion is greater than the maximum radial dimension of the eccentric atherectomy heads 100 at the end portions. In other words, the maximum radial dimension of each eccentric atherectomy head 100 gradually decreases from the center toward the end portions in the axial direction, forming a distribution with a larger maximum radial dimension in the middle and a smaller maximum radial dimension at the end portions. For example, if the maximum radial dimension of the eccentric atherectomy head 100 in the middle portion is 1.5 mm or 2.5 mm, the maximum radial dimension of the eccentric atherectomy heads 100 at the end portions can be 1 mm. The drive shaft arranged in this way can better control the revolution effect of the entire distal part during atherectomy, thereby controlling the grinding force and improving the safety of the operation. The eccentric atherectomy head 100 with a smaller end is also conducive to better entering the lesion location when initially contacting the plaque.

[0076] The present invention also provides a method for manufacturing an eccentric atherectomy head for an interventional medical device, comprising the steps of:

[0077] S100: manufacturing an eccentric base, wherein the eccentric base is the eccentric base in any of the above embodiments;

[0078] S200: forming an abrasive layer on the side of the eccentric base to obtain an eccentric grinding head 100.

[0079] In the above step S100, a cylindrical blank having a third curved surface 30 can be formed first, and the axis of the cylindrical blank is the aforementioned eccentric axis 31; then, an eccentric base is formed by removing material from the cylindrical blank. Specifically, the material on the outer side of the cylindrical blank can be removed first, that is, two rotational surfaces are formed, namely the first curved surface 20 and the second curved surface 40. For example, the excess portion of the cylindrical blank is removed with the central axis 11 as the rotation axis to obtain the first curved surface 20 and the second curved surface 40, except that the rotation axis is different from the rotation axis of the cylindrical blank (i.e., the aforementioned eccentric axis 31); then, the internal material is removed to form the connecting hole 10. Using this manufacturing method, the side of the manufactured eccentric grinding head 100 is smoother and easier to process.

[0080] Among them, the cylindrical blank can be processed into metal materials such as stainless steel, copper, platinum tungsten alloy, etc., and then the eccentric base is formed.

[0081] In the above step S200, the abrasive layer can be formed on the side of the eccentric substrate by nickel plating or brazing, wherein the abrasive particles in the abrasive layer can be diamond particles, CBN particles, SiC particles or aluminum oxide particles, and can be formed by the micro-powder of these abrasive particles, and can be connected to the eccentric substrate by nickel plating or brazing. The protruding height of the abrasive particles in the abrasive layer is preferably 5μm to 35μm, such as 5μm, 8μm, 10μm, 12μm, 15μm, 20μm, 22μm, 25μm, 30μm, 33μm or 35μm. Because an excessively large protruding height may cause the grinding debris to be too large, which is not conducive to discharge from the body and may even cause blockage; while an excessively small protruding height will remove too little plaque during grinding, and the grinding efficiency is too low. Using the above range can solve the above problems at the same time, that is, it can reduce the size of the grinding debris and improve the efficiency of the rotary grinding. Specifically, during manufacturing, abrasive particles with a particle size of 10 to 50 μm can be selected, such as; the particle size of the abrasive particles can be 10 um, 20 um, 30 um, 33 um, 35 um, 40 um, 45 um or 50 um, etc. After such a setting, the abrasive particles are more firmly bonded to the flexible shaft 200, and the grinding force is moderate, which will not cause damage to the blood vessels, and the generated grinding chips are basically below 30 um, which can be easily carried away by the blood or absorbed by the human body.

[0082] After the eccentric atherectomy head 100 is manufactured, the eccentric atherectomy head 100 and the flexible shaft 200 can be inserted and connected by common silver / gold-tin welding, adhesive bonding, or the connection method described above to form a drive shaft.

[0083] It should be noted that since the plaque is not regular and the cavity formed is not a regular cylindrical cavity, the diameter of the above-mentioned blood vessel or the cavity formed by the blood vessel and the plaque is only used for convenience of expression and does not limit the cavity to a cylindrical cavity. The radial direction is also only used for convenience of expression, referring to the direction perpendicular to the axial direction of the component and pointing from the axis to the outer surface, and does not limit the component in which it is located to be spherical, spherical, third curved surface, circular, etc.

[0084] Those skilled in the art will appreciate that, provided there is no conflict, the above preferred solutions can be freely combined and superimposed.

[0085] It should be understood that the above-mentioned embodiments are merely illustrative and non-restrictive. Without departing from the basic principles of the present invention, various obvious or equivalent modifications or substitutions that can be made by those skilled in the art to the above-mentioned details will be included in the scope of the claims of the present invention.

Claims

1. An eccentric atherectomy head for an interventional medical device, the eccentric atherectomy head having a connection hole for connecting to a flexible shaft; characterized in that: The eccentric grinding head includes an eccentric base and an abrasive layer, and the side surface of the eccentric base includes a first curved surface, a second curved surface and a third curved surface. The first curved surface and the second curved surface respectively cover at least two ends of the eccentric base and are symmetrical about a center plane between the two ends of the eccentric base. The two are respectively parts of the same revolution curved surface, and the revolution curved surface is formed by rotating a smooth convex curve around a central axis. The central axis is the axis of the connecting hole, and the distance from each point on the convex curve to the central axis gradually increases along the direction from the end surface of the eccentric base to the center plane; The third curved surface is at least a portion of a cylindrical surface, located in the middle section of the eccentric base, and its rotation axis is the eccentric axis, and the eccentric axis is parallel to the central axis of the connecting hole and has a distance therebetween; wherein the first curved surface and the second curved surface are partially connected at the center plane, forming at least one continuous and smooth generatrix on the side surface; the revolution curved surface intersects with the cylindrical surface to form a first intersection line and a second intersection line respectively located on both sides of the center plane; the portion of the revolution curved surface located between the center plane, the first intersection line, and the eccentric base and its end surface on the same side forms the first curved surface, the portion located between the center plane, the second intersection line, and the eccentric base and its end surface on the same side forms the second curved surface, and the portion of the cylindrical surface located between the first intersection line and the second intersection line forms the third curved surface; The abrasive layer is arranged on the side surface of the eccentric base.

2. The eccentric grinding head according to claim 1, characterized in that: The first curved surface, the second curved surface, and the third curved surface intersect at a point on the central plane.

3. The eccentric grinding head according to claim 1, characterized in that: The first curved surface and the second curved surface are connected in a partial area in the circumferential direction of the eccentric base, and the first intersection line and the second intersection line are connected at the center plane and transition smoothly.

4. The eccentric grinding head according to claim 1, characterized in that The convex curve is a circular arc, an elliptical arc, a parabola or a hyperbola.

5. The eccentric grinding head according to claim 1, characterized in that: The convex curve is an arc line, and the radius R of the convex curve, the axial length L of the eccentric base, the maximum radial dimension D of the eccentric base, the diameter d of the connecting hole, the eccentric distance M between the eccentric axis and the central axis, and the minimum wall thickness s of the eccentric base satisfy the following formula: R=[L 2 / 4+(D / 2+d / 2-M+s) 2 ] / [2*(D / 2+d / 2-M+s)]。 6. The eccentric grinding head according to claim 1, characterized in that The eccentric distance between the eccentric axis and the central axis is 0.05 mm to 0.6 mm; the maximum size of the eccentric base in the radial direction is 1.0 to 2.5 mm.

7. The eccentric grinding head according to claim 1, characterized in that The axial dimension of the eccentric base is 1.0 mm to 7.0 mm; the minimum wall thickness of the eccentric base is greater than or equal to 0.05 mm.

8. The eccentric grinding head according to any one of claims 1 to 7, characterized in that: The protruding height of the abrasive grains in the abrasive grain layer is 5 to 35 μm.

9. A drive shaft for an interventional medical device, comprising a flexible shaft and the eccentric atherectomy head according to any one of claims 1 to 8, wherein the eccentric atherectomy head is disposed at a distal end of the flexible shaft, and the connecting hole is plug-connected to the flexible shaft.

10. The drive shaft according to claim 9, wherein: In the distal region, the flexible shaft is provided with a plurality of eccentric atherectomies at intervals along its axial direction, the eccentric directions of the eccentric atherectomies are staggered in the circumferential direction of the flexible shaft, and the radial maximum dimension of the eccentric atherectomies in the middle portion is greater than the radial maximum dimension of the eccentric atherectomies at the two end portions.

11. The drive shaft according to claim 10, wherein: Along the axial direction of the flexible shaft, the radial maximum dimensions of the plurality of eccentric grinding heads gradually decrease from the middle to both ends.

12. An interventional medical device, characterized in that: The drive shaft comprises the drive shaft according to any one of claims 9 to 11.

13. A method for manufacturing an eccentric atherectomy head for an interventional medical device, characterized in that: Including steps: S100: manufacturing an eccentric base, wherein the side surface of the eccentric base includes a first curved surface, a second curved surface and a third curved surface, The first curved surface and the second curved surface respectively cover at least two ends of the eccentric base and are symmetrical about a center plane between the two ends of the eccentric base. The two are respectively parts of the same revolution curved surface, and the revolution curved surface is formed by rotating a smooth convex curve around a central axis. The central axis is the axis of the connecting hole, and the distance from each point on the convex curve to the central axis gradually increases along the direction from the end surface of the eccentric base to the center plane; The third curved surface is at least a portion of a cylindrical surface, located in the middle section of the eccentric base, and its rotation axis is the eccentric axis, and the eccentric axis is parallel to the central axis of the connecting hole and has a distance therebetween; wherein the first curved surface and the second curved surface are partially connected at the center plane, forming at least one continuous and smooth generatrix on the side surface; the revolution curved surface intersects with the cylindrical surface to form a first intersection line and a second intersection line respectively located on both sides of the center plane; the portion of the revolution curved surface located between the center plane, the first intersection line, and the eccentric base and its end surface on the same side forms the first curved surface, the portion located between the center plane, the second intersection line, and the eccentric base and its end surface on the same side forms the second curved surface, and the portion of the cylindrical surface located between the first intersection line and the second intersection line forms the third curved surface; S200: forming an abrasive layer on the side of the eccentric base to obtain an eccentric grinding head.

14. The manufacturing method according to claim 13, characterized in that: The abrasive layer is formed on the side surface of the eccentric substrate by nickel plating or brazing.

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