catheter

Abstract

The present invention provides a catheter that can firmly fix a shaft portion and a shaft seat and suppress the reduction of the dimensional accuracy of the radial outer side of the shaft seat. The catheter (10) comprises: a shaft portion (20) which is a tube body formed with an inner cavity (21) connected from the top end to the base end, and has a shaft portion base end surface (24) where the inner cavity (21) opens and a shaft portion outer surface (22) as the outer peripheral surface of the tube body; and a shaft seat (40) which is mounted on the base end of the shaft portion (20), the shaft seat (40) having a cylindrical receiving portion (41) for receiving the shaft portion (20), the receiving portion (41) having a shaft seat welding surface (49) directly welded to the shaft portion outer surface (22), and the absolute value of the residual strain of the receiving portion (41) decreases as it moves from the shaft seat welding surface (49) toward the radial outer side.

Description

Technical Field

[0001] The present invention relates to catheters. Background Art

[0002] In recent years, treatments within the lumen of blood vessels, etc., using catheters have become popular due to the fact that surgical invasion is very low. A catheter generally includes a shaft having an inner lumen connected from the top to the base end and a shaft seat disposed at the base end of the shaft. The shaft seat forms a passage connected to the inner lumen in order to connect to a syringe or the like.

[0003] As a method of fixing the base end of the shaft portion to the shaft seat, an insert molding method, a bonding method using an adhesive, and the like are known.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 10-180802

[0007] Patent Document 2: Japanese Utility Model Publication No. 63-17486 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the insert molding method described in Patent Document 1, the shaft is placed in an injection mold, a portion of the shaft is pressed with a fixing pin, and the resin for the shaft seat is injection molded at high temperature and high pressure. Therefore, there is a possibility that the shaft may be deformed or offset in the axial direction due to the fixing pin. The deformation of the shaft and the offset in the axial direction may reduce the fixing strength between the shaft and the shaft seat.

[0010] In addition, in the bonding method using adhesive described in Patent Document 2, if the gap between the outer diameter of the shaft portion and the inner cavity of the shaft portion receiving portion of the shaft seat is too small, the adhesive cannot flow in, and a gap remains between the shaft seat and the shaft portion, which may reduce the fixing strength between the shaft portion and the shaft seat. If the gap between the outer diameter of the shaft portion and the inner cavity of the shaft portion receiving portion of the shaft seat is too large, it is difficult for the gap between the shaft seat and the shaft portion to be completely filled with the adhesive, which may reduce the fixing strength between the shaft portion and the shaft seat.

[0011] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a guide tube capable of firmly fixing a shaft portion and a shaft seat and suppressing a decrease in dimensional accuracy of the radially outer side of the shaft seat.

[0012] Means for solving problems

[0013] The catheter of the present invention for achieving the above-mentioned purpose comprises: a shaft portion, which is a tube body formed with an inner cavity connected from the top end to the base end, and has a base end surface of the shaft portion where the inner cavity opens and an outer surface of the shaft portion which is the outer peripheral surface of the tube body; and a shaft seat, which is installed at the base end of the shaft portion, and the catheter is characterized in that the shaft seat has a cylindrical receiving portion for receiving the shaft portion, the receiving portion has a shaft seat welding surface directly welded to the outer surface of the shaft portion, and the absolute value of the residual strain of the receiving portion decreases as it moves radially outward from the shaft seat welding surface.

[0014] Effects of the Invention

[0015] In the conduit constructed as described above, due to welding, the absolute value of the residual strain of the housing portion decreases as it moves radially outward from the shaft seat welding surface, so that the shaft portion and the shaft seat can be firmly fixed and firmly welded, and the dimensional accuracy of the radial outer side of the shaft seat can be suppressed from being reduced.

[0016] Alternatively, the contour line of the absolute value of the residual strain of the receiving portion on the cross section passing through the axis of the receiving portion is formed into a circular arc shape that becomes convex as it approaches the radial outer side. Thus, the absolute value of the residual strain gradually decreases as it approaches the radial outer side and the two directions (top end direction and base end direction) of the axial direction from the largest shaft seat welding surface. Therefore, the shape distortion of the receiving portion can be effectively suppressed.

[0017] Alternatively, the base end surface of the shaft portion may be welded to the shaft seat. Thus, the shaft portion and the shaft seat can be fixed more firmly.

[0018] A shaft seat separation surface may also be formed on the top end side of the receiving portion, which is radially away from and opposite to the outer surface of the shaft portion. Thus, since the shaft portion becomes easy to bend inside the top end of the receiving portion, stress concentration on the shaft portion and damage to the shaft portion can be suppressed. In addition, the shaft portion becomes easy to bend inside the top end of the receiving portion, thereby, when the shaft portion bends, the force that is intended to peel off the shaft portion can be suppressed from acting on the shaft seat welding surface of the receiving portion, and the fixation of the shaft portion and the shaft seat can be effectively maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is a top view showing a catheter according to an embodiment.

[0020] Figure 2 It is a cross-sectional view showing the shaft seat and the base end portion of the shaft portion.

[0021] Figure 3 It is a cross-sectional view showing the front end portion of the shaft seat and the base end portion of the shaft portion.

[0022] Figure 4 It is a cross-sectional view showing the front end portion of the shaft seat before the shaft portion is fixed.

[0023] Figure 5 The figures are cross-sectional views showing the process of welding the shaft portion to the shaft seat, wherein (A) shows the state at the start of welding and (B) shows the state during welding.

[0024] Figure 6 It is a cross-sectional view showing the residual strain of the top end portion of the shaft seat and the base end portion of the shaft portion with contour lines. DETAILED DESCRIPTION

[0025] Hereinafter, the embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that, for the sake of convenience, the dimensional ratios of the accompanying drawings may be exaggerated and different from the actual ratios. In the following description, the side where the catheter is operated is referred to as the "base end side", and the side inserted into the living body is referred to as the "top end side".

[0026] like Figures 1 to 3 As shown, the catheter 10 of the embodiment of the present invention includes: a shaft 20, which is a long tube; a shaft seat 40, which is fixed to the base end of the shaft 20; and a soft anti-torsion protector 60, which is used to suppress the bending of the shaft 20. In addition to the catheter supporting the guide wire, the catheter 10 can also be a guide catheter, an angiography catheter, a microcatheter, or a balloon catheter with a lumen for expansion, and an image diagnosis catheter. In addition, the catheter 10 can be an overall replacement (OTW) type with a guide wire lumen connected from the top of the shaft to the shaft seat, or a quick replacement (RX) type with a guide wire lumen formed only at the top of the shaft. For example, the guide wire lumen of the RX-type balloon catheter is formed from the top of the shaft to the opening in the middle of the axial direction of the shaft. The expansion lumen of the RX-type balloon catheter for the flow of fluid for expanding the balloon is formed to be connected from the balloon to the shaft seat at the base end of the catheter.

[0027] The shaft portion 20 is formed with an inner cavity 21 that is connected from the distal end to the proximal end. The shaft portion 20 has a shaft portion outer surface 22, a shaft portion inner surface 23, and a shaft portion proximal end surface 24.

[0028] The shaft outer surface 22 is a radially outer surface of the shaft 20 as a tubular body, and extends from the top end to the base end of the shaft 20. The shaft outer surface 22 has a shaft base end side outer surface 25 formed from the base end of the shaft 20 toward the top end to a predetermined position. The shaft base end side outer surface 25 is surrounded and contained by the shaft seat 40. The shaft base end side outer surface 25 has a substantially uniform outer diameter along the axis X of the shaft 20. The shaft base end side outer surface 25 has: a shaft welding surface 26, which is welded to the shaft seat 40; and a shaft separation surface 27, which is arranged on the top end side of the shaft welding surface 26 and away from the shaft seat 40. The shaft separation surface 27 is not welded to the shaft seat 40, and is away from the shaft seat 40 with a gap therebetween.

[0029] The shaft portion inner surface 23 is a radially inner surface of the shaft portion 20 serving as a tube, and extends from the distal end to the proximal end of the shaft portion 20 .

[0030] The shaft portion proximal end surface 24 is a surface facing the proximal end side at the proximal end of the shaft portion 20 , and is formed so as to be cut perpendicularly to the axis X of the shaft portion 20 .

[0031] The shaft portion 20 in the present embodiment includes an inner layer 28 forming the shaft portion inner surface 23 , an outer layer 29 forming the shaft portion outer surface 22 , and a reinforcement body 30 embedded in the shaft portion 20 .

[0032] The constituent material of the outer layer 29 can include, for example, polyamide elastomer, polyester elastomer, polyurethane elastomer or a mixture of one or more thereof or a mixture of substances with different hardnesses, in addition to polyamide resin, polyester resin, polyolefin resin, and polyurethane resin. The outer layer 29 can also be a structure in which materials with different hardnesses are arranged in a manner that becomes softer from the base end to the top end.

[0033] The material constituting the inner layer 28 may be the same material as that constituting the outer layer 29 or a material different from that constituting the outer layer 29. In order to improve the sliding contact property of the inner peripheral surface of the shaft portion 20, the material constituting the inner layer 28 may be a fluorine-based resin material such as polytetrafluoroethylene resin.

[0034] The reinforcing body 30 reinforces the shaft 20 and is formed by weaving a plurality of reinforcing wires 31 into a cylindrical shape. Alternatively, the reinforcing body 30 may be formed by winding one or more reinforcing wires 31 into a spiral shape. The material of the outer layer 29 or the inner layer 28 enters the gaps between the plurality of reinforcing wires 31 of the reinforcing body 30. The reinforcing wires 31 are made of metal such as stainless steel and NiTi.

[0035] The shaft seat 40 includes a cylindrical housing portion 41 disposed on the top end side and housing the base end portion of the shaft portion 20, a shaft seat body 42 disposed on the base end side of the housing portion 41, a wing portion 52, a thread cutting protrusion 53, and an annular protrusion 54. The shaft seat 40 is formed with a shaft seat inner cavity 45 communicating from a shaft seat top end opening 43 formed at the top end of the housing portion 41 to a shaft seat base end opening 44 formed at the base end of the shaft seat body 42. The shaft seat inner cavity 45 includes a housing surface 46, which is the inner peripheral surface of the housing portion 41; an adjacent surface 47, which is opposite to the base end surface 24 of the shaft portion; and a shaft seat passage 48, which is the inner peripheral surface of the shaft seat body 42.

[0036] The receiving surface 46 includes: a shaft seat welding surface 49, which is directly welded to the shaft portion welding surface 26 of the shaft portion base end side outer surface 25; and a shaft seat separation surface 50, which is separated from the shaft portion separation surface 27 radially outward and opposite. The shaft seat welding surface 49 extends from the base end of the receiving surface 46 to the top end direction. The base end of the shaft seat welding surface 49 is connected to the adjacent surface 47. The shaft seat separation surface 50 extends from the top end of the shaft seat welding surface 49 to the top end direction. The gap between the shaft seat separation surface 50 and the shaft portion base end side outer surface 25 in the radial direction increases as it approaches the top end direction. It should be noted that the shaft seat separation surface 50 that forms a gap with the shaft portion base end side outer surface 25 may not be provided.

[0037] The abutment surface 47 is an annular surface facing the distal end and is formed substantially perpendicular to the axis X of the shaft portion 20 . The radially outer side of the abutment surface 47 is connected to the shaft seat welding surface 49 . The radially inner side of the abutment surface 47 is connected to the distal end of the shaft seat passage 48 .

[0038] The shaft seat passage 48 extends from the adjacent surface 47 toward the base end. The shaft seat passage 48 is formed in a tapered shape and has an inner diameter that gradually increases as it approaches the base end. Preferably, the shaft seat passage 48 is coaxial with the receiving surface 46 and further coaxial with the inner cavity 21. Preferably, the inner diameter of the top end of the shaft seat passage 48 is substantially consistent with the inner diameter of the shaft portion 20, but is not limited to this. A portion of the tapered shaft seat passage 48 may also have a Luer taper portion 51 that can be connected to a syringe (not shown). The guide wire and treatment catheter inserted from the shaft seat base end opening 44 smoothly pass through the shaft seat inner cavity 45 and the inner cavity 21 and protrude from the top end of the catheter 10. As a result, the guide wire and treatment catheter 10 can easily reach the target location such as the lesion.

[0039] The wing portion 52 is formed to protrude from two opposite locations on the outer peripheral surface of the shaft seat body 42 so that the surgeon can easily hold the shaft seat 40 for operation. The thread cutting protrusion 53 is formed on the outer peripheral surface of the base end side of the shaft seat body 42. The thread cutting protrusion 53 can be engaged with a locking type syringe or the like. The annular protrusion 54 is a protrusion formed on the outer peripheral surface of the housing portion 41 within a range of 360°. The annular protrusion 54 can be engaged with a groove formed on the inner peripheral surface of the anti-twist protector 60.

[0040] The material constituting the shaft seat 40 is not particularly limited, and may be any thermoplastic resin that can be injection molded, preferably one that easily transmits heat or electromagnetic waves, and specific examples thereof include polyolefin resins, polyamide resins, polycarbonate resins, and polyester resins.

[0041] Next, the method of welding the shaft portion 20 and the shaft seat 40 will be described. Figure 4As shown, the inner diameter of the receiving surface 46 on the top end side is larger than that on the base end side. Specifically, the inner diameter D1 of the top end opening 43 of the shaft seat is larger than the inner diameter D2 of the top and base ends of the shaft seat welding surface 49. In addition, the inner diameter D3 of the top end of the shaft seat passage 48 is smaller than the inner diameter D2 of the base end of the shaft seat welding surface 49. The inner diameter D2 of the shaft seat welding surface 49 is substantially consistent with the outer diameter of the outer surface 25 on the base end side of the shaft portion. The inner diameter D1 of the top end opening 43 of the shaft seat is, for example, 0.92 mm. The inner diameter D2 of the base end of the shaft seat welding surface 49 is, for example, 0.88 mm. The inner diameter D3 of the top end of the shaft seat passage 48 is, for example, 0.57 mm.

[0042] First, the base end side of the shaft portion 20 is inserted into the receiving portion 41 so that the base end face 24 of the shaft portion abuts against the adjacent face 47. It should be noted that the base end face 24 of the shaft portion may not abut against the adjacent face 47, but there is a gap between the base end face 24 of the shaft portion and the adjacent face 47. In addition, the base end of the outer surface 25 of the base end side of the shaft portion abuts against the base end of the shaft seat welding surface 49. It should be noted that the outer surface 25 of the base end side of the shaft portion may not abut against the shaft seat welding surface 49, but there is a gap between the outer surface 25 of the base end side of the shaft portion and the shaft seat welding surface 49.

[0043] Next, a core shaft (not shown) is inserted into the inner cavity 21 of the shaft portion 20, and the outer surface 25 of the base end side of the shaft portion and the receiving portion 41 of the shaft seat 40 are heated. As a result, the outer surface 25 of the base end side of the shaft portion and the receiving surface 46 are melted, and the shaft seat welding surface 49 and the shaft portion welding surface 26 are welded. The shaft seat welding surface 49 and the shaft portion welding surface 26 can also be mixed to form an integrated structure. The heating method is not particularly limited, and for example, a method of irradiating electromagnetic waves with a wavelength that is transparent to the shaft seat 40 but not transparent to the outer surface 22 of the shaft portion can be cited. Since the electromagnetic waves do not penetrate the outer surface 22 of the shaft portion, the outer surface 25 of the base end side of the shaft portion is first heated to melt it. Then, the heat of the outer surface 25 of the base end side of the shaft portion is transferred to the receiving portion 41, causing the receiving portion 41 to melt.

[0044] Electromagnetic waves include infrared rays in addition to heat, microwaves, and visible light. Infrared rays are near infrared rays with a wavelength of about 0.7 μm to 2.5 μm, mid infrared rays with a wavelength of about 2.5 μm to 4 μm, or far infrared rays with a wavelength of about 4 μm to 1000 μm. They may be near infrared rays, mid infrared rays, or far infrared rays alone, or may include two or more of them, and may also include visible light or microwaves.

[0045] The method of irradiating the electromagnetic wave is not particularly limited, and semiconductor solid lasers such as YAG lasers using rubidium, fiber lasers, etc. may be used.

[0046] Electromagnetic wave transmission means that it appears transparent to the naked eye under visible light, and the measured transmittance (hereinafter referred to as transmittance) is 80% or more, more preferably 85% or more. The transmittance can be measured by irradiating a sheet having a thickness of 0.4 mm to 0.5 mm made by melting and pressing resin pellets with electromagnetic waves of a specific wavelength, and using a spectroscopic analysis device, such as a Fourier transform infrared / near infrared spectroscopic analysis device. Therefore, electromagnetic waves are not limited to visible light, and electromagnetic wave transmission includes the case where it is transparent with respect to a specific wavelength even if it appears to be colored or opaque to the naked eye.

[0047] In addition, electromagnetic wave opacity means that it appears opaque or colored to the naked eye under visible light, and the transmittance is less than 80%, preferably less than 10%, and more preferably less than 1%. Therefore, electromagnetic waves are not limited to visible light, and electromagnetic wave opacity includes the case where it appears transparent to the naked eye but is opaque or absorbs specific wavelengths.

[0048] The outer layer 29 may also be mixed with a pigment that does not transmit or absorb heat or electromagnetic waves in an amount of 0.01wt% or more and less than 10wt% of the total resin, preferably 0.05wt% or more and less than 5wt%, and more preferably 0.1wt% or more and less than 1%. Alternatively, the outer layer 29 may not contain a pigment, a contrast agent, etc., and the resin forming the outer layer 29 may be a substance with low transmittance with respect to a specific wavelength. Alternatively, the outer layer 29 may replace the pigment or mix a metal having X-ray contrast properties with the pigment.

[0049] The pigment is not particularly limited and may be a pigment emitting white, black, blue, red, yellow or a mixture thereof, and a black pigment such as carbon black is preferred as a substance that easily absorbs electromagnetic waves. X-ray contrast agents are compounds of gold, bismuth or tungsten, and powdered substances are more preferred.

[0050] For example, Figure 5 As shown in (A), when the shaft 20 and the shaft seat 40 are welded by irradiating infrared laser L, the electromagnetic wave passing through the shaft seat 40 which is transparent to the wavelength of the irradiated infrared laser L is absorbed by the opaque resin or pigment of the outer layer 29 of the shaft 20, and mainly generates heat. As a result, the resin of the outer layer 29 melts, and the heat H is transferred to the receiving portion 41 of the shaft seat 40, and at least a part of the receiving surface 46 melts. Figure 5As shown in (B), the melted receiving surface 46 is reduced in diameter and closely fits with the outer surface 25 on the base end side of the shaft portion, and is fused to the outer surface 25 on the base end side of the shaft portion. Thus, the shaft seat welding surface 49 and the shaft welding surface 26 are formed by welding. At this time, the receiving surface 46 is melted and reduced in diameter, but the outer peripheral surface of the receiving portion 41 is hardly melted due to almost no heat transfer, and is hardly deformed. Therefore, due to the reduction in diameter of the receiving surface 46, the material constituting the receiving surface 46 flows and fills the gap between the outer surface 25 on the base end side of the shaft portion, and as a result, the length of the receiving portion 41 along the axis X is reduced. Thus, the receiving portion 41 is well fused to the outer surface 25 on the base end side of the shaft portion without a gap. In addition, the base end surface 24 of the shaft portion and the adjacent surface 47 are also melted and fused due to the heat of the outer layer 29. It should be noted that the base end surface 24 of the shaft portion may not be fused to the adjacent surface 47.

[0051] like Figure 3 As shown in FIG. 1 , the shaft seat separation surface 50 located at the top of the shaft seat welding surface 49 is not welded to the shaft separation surface 27, and a gap is maintained between the shaft separation surface 27. If the entire shaft seat welding surface 49 located at the base end side relative to the shaft seat separation surface 50 is welded to the shaft welding surface 26, the irradiation of the infrared laser L is stopped. Thus, the fixing of the shaft seat 40 and the shaft 20 is completed. If the melted material cools and solidifies, as shown in FIG. Figure 6 As shown in FIG. 4 , the shaft seat 40 has residual strain. It should be noted that the residual strain can be measured using an X-ray residual stress measuring device, a two-dimensional multi-bend measuring device, etc. In the cross section passing through the axis X, as shown in FIG. Figure 6 As shown, the contour line C drawn by connecting the parts of the shaft seat 40 with the same residual strain is formed into a circular arc shape that becomes convex as it approaches the radial outer side. That is, the absolute value of the residual strain is large at the approximate center of the welding range of the receiving portion 41 along the axis X, and decreases as it approaches the radial outer side, and decreases toward the top end direction and the base end direction along the axis X. In other words, the contour line C is formed into a shape that is similar to a part of an elliptical arc having a major axis extending along the axis X. In the three-dimensional shape of the shaft seat 40, the contour surface connecting the parts of the shaft seat 40 with the same residual strain is formed into a shape that is similar to a part of the outer peripheral surface of a rotating ellipsoid having a major axis extending along the axis X.

[0052] As described above, the catheter 10 of the present embodiment is a tube body formed with an inner cavity 21 connected from the top end to the base end, and comprises: a shaft portion 20, which has a shaft portion base end surface 24 at which the inner cavity 21 opens and a shaft portion outer surface 22 as the outer peripheral surface of the tube body; and a shaft seat 40, which is installed at the base end of the shaft portion 20, the shaft seat 40 has a cylindrical housing portion 41 for housing the shaft portion 20, the housing portion 41 has a shaft seat welding surface 49 directly welded to the shaft portion outer surface 22, and the absolute value of the residual strain of the housing portion 41 decreases as it moves radially outward from the shaft seat welding surface 49.

[0053] In the catheter 10 configured as described above, the absolute value of the residual strain of the housing portion 41 decreases as it moves from the shaft seat welding surface 49 to the radially outer side due to welding, so the shaft portion 20 and the shaft seat 40 can be firmly fixed and firmly welded, and the dimensional accuracy of the radially outer side of the shaft seat 40 can be suppressed from being reduced. Therefore, when the high pressure of the contrast medium injected into the catheter 10 acts, when the shaft portion 20 is pulled out of the body, and when a tensile force acts between the shaft seat 40 and the shaft portion 20, it is possible to prevent the shaft portion 20 from being pulled out of the shaft seat 40. In addition, since the dimensional change of the radially outer side of the housing portion 41 can be reduced, it is easy to attach components such as the anti-twist protector 60 to the outer side of the housing portion 41. In addition, when the compressive residual strain decreases as it moves from the shaft seat welding surface 49 to the radially outer side, the fixing force of the shaft seat 40 with respect to the shaft portion 20 can be increased.

[0054] In addition, the contour line C of the absolute value of the residual strain of the receiving portion 41 on the cross section passing through the axis of the receiving portion 41 is formed into a circular arc shape that becomes convex as it approaches the radial outer side. As a result, the absolute value of the residual strain gradually decreases as it approaches the radial outer side and the two directions of the axial direction (the tip direction and the base end direction) from the position of the largest shaft seat welding surface 49. Therefore, the shape distortion of the receiving portion 41 can be effectively suppressed.

[0055] In addition, the shaft portion base end surface 24 is welded to the shaft seat 40. Thus, the shaft portion 20 and the shaft seat 40 can be fixed more firmly.

[0056] In addition, a shaft seat separation surface 50 is formed on the top end side of the receiving portion 41, which is away from and opposite to the shaft portion outer surface 22 in the radial direction. As a result, since the shaft portion 20 becomes easy to bend inside the top end of the receiving portion 41, stress concentration on the shaft portion 20 can be suppressed, and damage to the shaft portion 20 can be suppressed. In addition, the shaft portion 20 becomes easy to bend inside the top end of the receiving portion 41, and thus, when the shaft portion 20 is bent, the force of the shaft portion 20 to peel off can be suppressed from acting on the shaft seat welding surface 49 of the receiving portion 41, and the fixing of the shaft portion 20 and the shaft seat 40 can be effectively maintained.

[0057] It should be noted that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made by those skilled in the art within the technical concept of the present invention. For example, the heating of the shaft 20 can also be performed by high-frequency induction heating using electromagnetic induction heating. The conductor of electromagnetic induction is, for example, the reinforcement 30.

[0058] It should be noted that the present application is based on Japanese Patent Application No. 2020-95665 filed on June 1, 2020, and the disclosed contents are incorporated herein by reference in their entirety.

[0059] Description of Reference Numerals

[0060] 10 Catheter

[0061] 20 Shaft

[0062] 21 Lumen

[0063] 22 Shaft outer surface

[0064] 23 Inner surface of shaft

[0065] 24 Shaft base end surface

[0066] 25 Outer surface of the shaft base end

[0067] 26 Shaft welding surface

[0068] 27 Shaft separation surface

[0069] 28 Inner layer

[0070] 29 Outer layer

[0071] 30 Strengthen the body

[0072] 40 Axle seat

[0073] 41 Containment Department

[0074] 42 Shaft seat body

[0075] 43 Axle seat top opening

[0076] 44 Shaft seat base opening

[0077] 45 Shaft seat inner cavity

[0078] 46 Shelter surface

[0079] 47 Adjacent surface

[0080] 48 Shaft seat passage

[0081] 49 Shaft seat welding surface

[0082] 50 Shaft-seat separation surface

[0083] 60 Anti-twist protector

Claims

1. A catheter, comprising: The shaft portion is a tubular body having an inner cavity extending from the distal end to the proximal end, and includes a proximal end face of the shaft portion where the inner cavity is opened and an outer surface of the shaft portion which is an outer peripheral surface of the tubular body; and A shaft seat, which is mounted on the base end of the shaft portion, The catheter is characterized in that The shaft seat has a cylindrical receiving portion for receiving the shaft portion. The receiving portion has a shaft seat welding surface directly welded to the outer surface of the shaft portion, The absolute value of the residual strain of the housing portion decreases radially outward from the shaft seat welding surface, and a contour line of the absolute value of the residual strain of the housing portion on a cross section passing through the axis of the housing portion is formed in an arc shape that becomes convex radially outward.

2. The catheter according to claim 1, characterized in that The base end surface of the shaft portion is welded to the shaft seat.

3. The catheter according to claim 1 or 2, characterized in that The housing portion has a shaft seat separation surface on the front end side thereof, which is away from and faces the outer surface of the shaft portion in the radial direction outward.

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