Endoscope and method for manufacturing endoscope

Abstract

The present invention provides an endoscope with excellent fixation strength between tubes connected in the longitudinal direction. The endoscope includes: a first tube; a second tube having a distal end located more distally than a distal end of the first tube; and an adhesive located between, and fixing, the first tube and the second tube. The first tube has at least one cut surface in a portion in contact with the adhesive. The second tube has a melt surface in a portion in contact with the adhesive.

Description

Endoscope and method for manufacturing an endoscope

[0001] The present disclosure relates to an endoscope and a method for manufacturing an endoscope.

[0002] In the medical field, endoscopes are used. For example, in Patent Document 1, there is an inner layer tube having a groove non-parallel to the axial direction on the outer peripheral surface and made of an elastomer or a resin having flexibility, and the groove of the inner layer tube is filled and the outer periphery is covered. An endoscope including an outer layer made of an elastomer resin softer than the base material of the inner layer tube and a blade formed by a metal wire disposed only at a location other than the groove in the outer layer is disclosed.

[0003] Japanese Unexamined Patent Application Publication No. 2020-171420

[0004] In forming the shaft portion of the endoscope, for example, when two tubes are connected and fixed in the longitudinal direction, the inventor's study found that the fixing strength between the tubes is likely to decrease. The problem to be solved by the present disclosure is to provide an endoscope excellent in the fixing strength between tubes connected in the longitudinal direction. Another problem to be solved by the present disclosure is to provide a method for manufacturing an endoscope excellent in the fixing strength between tubes connected in the longitudinal direction.

[0005] The endoscope according to an embodiment of the present disclosure that has solved the above problems is as follows. [1] A first tube, a second tube whose distal end is located on the distal side of the distal end of the first tube, and an adhesive located between and fixing the first tube and the second tube, wherein the first tube has at least one cut surface in a portion in contact with the adhesive, and the second tube has a melted surface in a portion in contact with the adhesive.

[0006] As described above, the first tube having at least one cut surface increases the contact area between the first tube and the adhesive, thereby improving the adhesive strength. Furthermore, the second tube having an irregularly shaped molten surface improves the durability against multidirectional forces at the fixing point between the tubes. These combined effects improve the fixing strength between the tubes. In particular, improving the fixing strength between tubes in the part inserted into the body enhances safety.

[0007] The endoscope according to the embodiment is preferably any one of the following [2] to

[12] . [2] The endoscope according to [1], wherein the first tube has a plurality of lumens extending in the longitudinal direction of the first tube, and the adhesive has a plurality of lumens communicating with the plurality of lumens and extending in the longitudinal direction. [3] The endoscope according to [2], wherein the second tube has a plurality of lumens communicating with the plurality of lumens of the adhesive and extending in the longitudinal direction. [4] The endoscope according to any one of the following [1] to [3], wherein the first tube has a convex portion that protrudes from the proximal side toward the distal side in the portion in contact with the adhesive, and the second tube has a concave portion that is recessed from the proximal side toward the distal side in the portion in contact with the adhesive. [5] The endoscope according to [4], wherein the convex portion has an outer surface extending in the circumferential direction of the first tube, and the at least one cutting surface includes the outer surface. [6] The endoscope according to [4] or [5], wherein the convex portion has an uncut distal end surface. [7] The endoscope according to any one of [4] to [6], wherein the protrusion has a tapered portion whose outer diameter decreases from the proximal side to the distal side. [8] The endoscope according to any one of [4] to [7], wherein the adhesive has a first portion adjacent to the base end of the protrusion, and a second portion located distal to the first portion, the wall thickness in the radial direction of the first tube being thinner than that of the first portion. [9] The endoscope according to [8], wherein the adhesive has a third portion located distal to the second portion, the wall thickness in the radial direction being thicker than that of the second portion.

[10] The endoscope according to any one of [1] to [9], wherein the second tube has a lower Shore D hardness than the first tube.

[11] The endoscope according to any one of [1] to

[10] , wherein the first tube contains polytetrafluoroethylene.

[12] The endoscope according to any one of [1] to

[11] , wherein the adhesive contains epoxy resin, and the second tube contains elastomer.

[0008] A method for manufacturing an endoscope according to an embodiment of the present disclosure that can solve the above problems is as follows:

[13] A method for manufacturing an endoscope comprising the steps of: cutting the distal end of a first tube having a plurality of lumens extending in the longitudinal direction to provide a cut portion; arranging a plurality of core materials in the plurality of lumens such that the distal ends of the plurality of core materials are exposed; applying an adhesive to the cut portion; arranging a second tube such that the proximal end of the second tube is in contact with the adhesive; and melting the second tube by heating.

[0009] As described above, by cutting the distal end of the first tube, the contact area between the first tube and the adhesive can be increased, thereby improving the adhesive strength. Furthermore, by bringing the proximal end of the second tube into contact with the adhesive and melting the second tube by heating, an irregularly shaped molten surface is formed on the part of the second tube that is in contact with the adhesive, thereby improving the durability against multidirectional forces at the fixing point between the tubes. These combined effects can improve the fixing strength between the tubes. In particular, improving the fixing strength between tubes in the part inserted into the body enhances safety.

[0010] The method for manufacturing an endoscope according to the embodiment is preferably any one of the following

[14] to

[25] .

[14] The method for manufacturing an endoscope according to

[13] , wherein, after the step of melting the second tube by heating, the adhesive has a plurality of lumens that communicate with the plurality of lumens and extend in the longitudinal direction, and the second tube has a plurality of lumens that communicate with the plurality of lumens of the adhesive and extend in the longitudinal direction.

[15] The method for manufacturing an endoscope according to

[13] or

[14] , further comprising the step of covering the first tube, the adhesive, and the second tube with a heat shrinkable tube after the step of applying the adhesive and before the step of melting the second tube by heating.

[16] The method for manufacturing an endoscope according to any one of the following

[13] to

[15] , wherein, in the step of arranging the second tube, the second tube is arranged such that the proximal end of the adhesive is exposed.

[17] A method for manufacturing an endoscope according to any one of

[13] to

[16] , further comprising the step of covering each of the multiple core materials with a resin tube before the step of arranging the multiple core materials in the multiple lumens.

[18] A method for manufacturing an endoscope according to any one of

[13] to

[17] , wherein the cutting portion has a convex portion that protrudes from the proximal side toward the distal side.

[19] A method for manufacturing an endoscope according to

[18] , wherein the convex portion has an uncut distal end face and an outer surface that extends in the circumferential direction and is cut.

[20] A method for manufacturing an endoscope according to

[18] or

[19] , wherein the convex portion has a tapered portion whose outer diameter decreases from the proximal side toward the distal side.

[21] A method for manufacturing an endoscope according to any one of

[13] to

[20] , wherein the first tube contains a first resin, and the second tube contains a second resin having a lower melting point than the resin of the first tube.

[22] A method for manufacturing an endoscope according to

[21] , wherein the first resin contains polytetrafluoroethylene.

[23] A method for manufacturing an endoscope according to any one of

[13] to

[22] , further comprising the step of performing a hydrophilic treatment on the cutting portion before the step of applying the adhesive.

[24] A method for manufacturing an endoscope according to any one of

[21] to

[23] , wherein the second resin comprises an elastomer.

[25] A method for manufacturing an endoscope according to any one of

[13] to

[24] , wherein the adhesive comprises an epoxy resin.

[0011] According to this disclosure, it is possible to provide an endoscope with excellent fixation strength between longitudinally connected tubes. According to this disclosure, it is possible to provide a method for manufacturing an endoscope with excellent fixation strength between longitudinally connected tubes.

[0012] Figure 1 is a side view of an endoscope according to an embodiment. Figure 2 is a side view of the endoscope of Figure 1, showing the second tube and adhesive, the distal end of the first tube and its vicinity. Figure 3 is a side view of Figure 2, with the second tube and adhesive omitted from the illustration. Figure 4 is a side view of Figure 2, with the second tube omitted from the illustration. Figure 5 is a cross-sectional view taken along V-V in Figure 2. Figure 6 is a cross-sectional view taken along VI-VI in Figure 2. Figure 7 is a cross-sectional view taken along VII-VII in Figure 2. Figure 8 is a cross-sectional view taken along VIII-VIII in Figure 2. Figure 9 is a cross-sectional view taken along IX-IX in Figure 2. Figure 10 shows the distal end face of the endoscope of Figure 1. Figure 11 is a side view of the first tube in the manufacturing process of an endoscope according to an embodiment. Figure 12 is a side view of the first tube of Figure 11 when a cut portion is provided. Figure 13 is a side view of the first tube of Figure 12 when multiple core materials are placed in multiple lumens. Figure 14 is a side view when the core material is covered with a resin tube. Figure 15 is a side view of the first tube in Figure 13 with adhesive applied to the cut portion. Figure 16 is a side view of the second tube in Figure 15 positioned in contact with the adhesive. Figure 17 is a side view of the first tube, adhesive, and second tube in Figure 16 covered with heat shrink tubing. Figure 18 is a side view of the second tube in Figure 17 after it has been melted by heating. Figure 19 is a side view of the shaft formed by removing the heat shrink tubing and multiple core materials in Figure 18. Figure 20 is a cross-sectional view taken along the line XX-XX of Figure 19. Figure 21 is a cross-sectional view taken along the line XXI-XXI of Figure 19. Figure 22 is a cross-sectional view taken along the line XXII-XXII of Figure 19. Figure 23 is a cross-sectional view taken along the line XX-XX of the shaft in Figure 19 with operating wires and wiring for transmitting image information arranged in multiple lumens. Figure 24 is a side view of the endoscope of the embodiment. Figure 25 is a view of the distal end face of the endoscope in Figure 24.

[0013] The following describes the disclosure in more detail based on the embodiments described below. However, the disclosure is not limited by the embodiments described below, and it is certainly possible to implement it with appropriate modifications to conform to the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the disclosure. In addition, for convenience, some component reference numerals, etc., may be omitted in the drawings, in which case refer to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to helping understand the features of the disclosure.

[0014] The endoscope according to this embodiment comprises a first tube, a second tube whose distal end is located distal to the distal end of the first tube, and an adhesive located between the first and second tubes and fixing them together. The first tube has at least one cut surface in the portion in contact with the adhesive, and the second tube has a molten surface in the portion in contact with the adhesive. As described above, the first tube having at least one cut surface increases the contact area between the first tube and the adhesive, thereby improving the adhesive strength. Furthermore, the second tube having an irregularly shaped molten surface improves the durability against multidirectional forces at the fixing portion between the tubes. These combined effects improve the fixing strength between the tubes. In particular, improving the fixing strength between the tubes in the portion inserted into the body enhances safety.

[0015] The endoscope according to the embodiment will be described below with reference to each figure. Figure 1 is a side view of the endoscope according to the embodiment. Figure 2 is a side view of the endoscope of Figure 1, showing the second tube and adhesive, the distal end of the first tube and its vicinity. Figure 3 is a side view of Figure 2, with the second tube and adhesive omitted from the illustration. Figure 4 is a side view of Figure 2, with the second tube omitted from the illustration. Figure 5 is a cross-sectional view of Figure 2 taken along line V-V. Figure 6 is a cross-sectional view of Figure 2 taken along line VI-VI. Figure 7 is a cross-sectional view of Figure 2 taken along line VII-VII. Figure 8 is a cross-sectional view of Figure 2 taken along line VIII-VIII. Figure 9 is a cross-sectional view of Figure 2 taken along line IX-IX. Figure 10 shows the distal end face of the endoscope of Figure 1. Note that wires, wiring, etc. are omitted in Figure 1. Figure 2 is a side view of the field of view from the top to the bottom of Figure 1, with tips, etc., omitted from the illustration.

[0016] As shown in Figure 1, the endoscope 91 according to this embodiment includes a first tube 1, a second tube 2, and an adhesive 3. As shown in Figure 2, the distal end 2B of the second tube 2 is located distal to the distal end 1B of the first tube 1. The adhesive 3 is located between the first tube 1 and the second tube 2 and fixes them together.

[0017] As shown in Figures 3 and 4, the first tube 1 has at least one cut surface 1C in the portion in contact with the adhesive 3. Hereinafter, the at least one cut surface 1C may be simply referred to as the cut surface 1C. The cut surface 1C can increase the contact area between the first tube 1 and the adhesive 3. The cut surface 1C can be formed, for example, by cutting the distal end of the tube that will become the first tube 1, and can be formed by removing a part of the distal end of the tube using a cutter, grinder, or the like.

[0018] Preferably, the first tube 1 has a protrusion 1H that extends from the proximal side to the distal side in the portion in contact with the adhesive 3. Such a protrusion 1H makes it easier for the adhesive 3 to adhere to the first tube 1.

[0019] The shape of the protrusion 1H is preferably a cylinder, a frustocone, a polygonal prism, a frustocone, or a combination thereof, and more preferably a cylinder, a frustocone, or a combination thereof. This makes it less likely for the protrusion 1H to be damaged by external forces. These shapes are as shown in the side view in Figure 3.

[0020] The protrusion 1H preferably has an outer surface 1H1 extending in the circumferential direction 1Y. Furthermore, it is preferable that at least one cut surface 1C includes the outer surface 1H1. In Figure 3, the outer surface 1H1 is oriented from the inside to the outside in the radial direction 1D of the first tube 1. The adhesion of the adhesive 3 to the outer surface 1H1 improves the fixing strength in the radial direction 1D. The shape of the outer surface 1H1 is preferably curved. Being curved improves the strength of the protrusion 1H against external forces in the radial direction 1D. Although not shown, the protrusion 1H may have a tapered portion in which the outer diameter decreases from the distal side to the proximal side. In this case, the second tube 2 becomes less likely to detach from the first tube 1 when the first tube 1 is pulled back.

[0021] It is preferable that the protrusion 1H has an uncut distal end face 1H2. In Figure 3, the distal end face 1H2 is oriented in the direction from the proximal to the distal in the longitudinal direction 1X of the first tube 1. The adhesion of adhesive 3 to the distal end face 1H2 improves the fixing strength in the longitudinal direction 1X. Furthermore, the strength of the protrusion 1H is more easily maintained because the distal end face 1H2 of the protrusion 1H is not cut. It is preferable that the distal end face 1H2 of the protrusion 1H is flat.

[0022] The convex portion 1H preferably has a tapered portion 1H3 whose outer diameter decreases from the proximal to the distal side. Furthermore, it is preferable that at least one cutting surface 1 includes the tapered surface of the tapered portion 1H3. Even if interfacial delamination occurs between the convex portion 1H and the adhesive 3 due to kinking during insertion into the body, the tapered portion 1H3 can suppress the propagation of delamination in the longitudinal direction 1X. Furthermore, as shown in Figure 4, the adhesive 3 can be applied thickly near the tapered portion 1H3, further improving the fixing strength. The tapered portion 1H3 is preferably a curved surface. Being a curved surface improves the strength of the tapered portion 1H3 against external forces in the radial direction 1D.

[0023] As shown in Figure 3, it is preferable that the first tube 1 has a base surface 1Cs in the portion adjacent to the protrusion 1H, which is oriented from the proximal to the distal direction in the longitudinal direction 1X. Furthermore, it is preferable that at least one cut surface 1C includes the base surface 1Cs. This further increases the contact area between the first tube 1 and the adhesive 3 and improves the fixing strength in the longitudinal direction 1X. It is preferable that the shape of the base surface 1Cs is an annular plane. This makes it easier for the adhesive 3 to adhere around the protrusion 1H.

[0024] Preferably, at least one cutting surface 1C includes at least two surfaces selected from the group consisting of a base surface 1Cs, an outer surface 1H1, and the tapered surface of the tapered portion 1H3, and more preferably includes the base surface 1Cs, the outer surface 1H1, and the tapered surface of the tapered portion 1H3. This improves the fixing strength in multiple directions. In this case, it is preferable that the base surface 1Cs and the outer surface 1H1 are in contact, and it is preferable that the outer surface 1H1 and the tapered surface of the tapered portion 1H3 are in contact. Multiple cutting surfaces in this contact can be formed, for example, by continuously cutting the distal end of the tube in multiple directions. On the other hand, at least one cutting surface 1C may have multiple cutting surfaces that are not in contact with each other.

[0025] The first tube 1 preferably contains a first resin. The first resin is preferably a thermoplastic resin. This makes it easier to mold the tube that will form the first tube 1 by extrusion molding or the like. The first resin may contain, for example, fluororesin; polyester such as polyethylene terephthalate; polyolefin such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer; polyamide; polyimide; polyamide-imide; polyurethane; rubber such as silicone rubber; elastomer such as polyolefin elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer; or a combination thereof. The fluororesin preferably contains polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, or a combination thereof. The first resin preferably contains a fluororesin, and more preferably contains polytetrafluoroethylene.

[0026] Preferably, the first tube 1 contains fluororesin in at least a portion of its outer surface. This improves insertability when the first tube 1 is inserted into the body with at least a portion exposed, as shown in Figures 2 and 5. Preferably, the first tube 1 does not have grooves on its outer surface in at least the portion of the outer surface of the first tube 1 that is exposed. This makes it easier to insert the first tube 1 into the body.

[0027] The first tube 1 preferably has a plurality of lumens 1L extending in the longitudinal direction 1X. The first tube 1 preferably contains a fluororesin in at least a portion of the part of the tube that is in contact with the plurality of lumens 1L. This improves the sliding properties of the member inserted into the plurality of lumens 1L.

[0028] The first tube 1 is preferably made of a fluororesin. Specifically, the first tube 1 being made of a fluororesin means that it contains fluororesin in an amount of 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. In addition to the fluororesin, the first tube 1 may also contain additives. The additives may include, for example, fillers, colorants, plasticizers, lubricants, antistatic agents, flame retardants, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, or mixtures thereof.

[0029] Although not shown in the figures, the first tube 1 may have a plurality of inner layers that are in contact with a plurality of lumens 1L, and an outer layer that covers the plurality of inner layers. In this case, the plurality of inner layers may contain the fluororesin exemplified as the first resin, and the outer layer may contain a resin other than the fluororesin among the resins exemplified as the first resin.

[0030] The adhesive 3 only needs to adhere to at least a portion of the cut surface 1C of the first tube 1, but it is preferable that it adheres to the entire cut surface 1C. It is even more preferable that the adhesive 3 also adheres to the portion of the first tube 1 adjacent to the cut surface 1C, for example, the distal end surface 1H2 of the protrusion 1H. This improves the fixing strength.

[0031] Adhesive 3 is preferably fully solidified from the viewpoint of fixing strength, but may be in the process of solidification. Adhesive 3 preferably contains epoxy resin. The epoxy resin improves the tensile strength between tubes. The epoxy resin preferably contains bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, or a combination thereof. Adhesive 3 is preferably further containing a curing component. The curing component preferably contains polyamine compounds such as aliphatic polyamines, aromatic amines, polyamidoamines, and polyether polyamines; phenol compounds such as novolac, cresol novolac, and bisphenol A type novolac; acid anhydride compounds such as tetrahydro phthalic anhydride and hexahydro phthalic anhydride; dicyandiamide compounds; imidasol compounds; polythiol compounds; or a combination thereof. Adhesive 3 may further contain additives such as catalysts, fillers, colorants, plasticizers, lubricants, antistatic agents, flame retardants, antioxidants, UV absorbers, hydrolysis inhibitors, or mixtures thereof to promote the curing reaction.

[0032] The adhesive 3 is not limited to epoxy adhesives, but may also be, for example, a urethane adhesive, a cyanoacrylate adhesive, or a silicone adhesive.

[0033] Adhesive 3 is preferably a room-temperature curing type or a heat-curing type, and more preferably a room-temperature curing type. Adhesive 3 may be a one-component, two-component, or three-component adhesive, but is preferably a two-component or three-component adhesive.

[0034] The cutting surface 1C may be subjected to a hydrophilic treatment. For example, if the cutting surface 1C contains polytetrafluoroethylene and the adhesive 3 contains epoxy resin, the hydrophilic treatment makes it easier for the adhesive 3 to adhere to the cutting surface 1C. Examples of hydrophilic treatments include tetraetch treatment, fluorobonder treatment, and plasma treatment, with tetraetch treatment being preferred. Examples of hydrophilic treatment agents include tetraetch (registered trademark) and fluorobonder (registered trademark), which are effective when hydrophilizing fluororesins. Furthermore, plasma treatment can be used to impart hydrophilic groups to resins other than fluororesins, thereby performing hydrophilic treatment. When performing hydrophilic treatment, it is preferable that the portion adjacent to the cutting surface 1C, for example, the distal end face 1H2 of the convex portion 1H, is also subjected to the hydrophilic treatment.

[0035] As shown in Figure 4, it is preferable that the adhesive 3 has a first portion 3P1 adjacent to the base end 1H4 of the protrusion 1H, and a second portion 3P2 located distal to the first portion 3P1, with a wall thickness in the radial direction 1D of the first tube 1 being thinner than that of the first portion. The thickness of the first portion 3P1 makes it easier to prevent the adhesive 3 from peeling off from the base end. On the other hand, the thinness of the second portion 3P2 makes it easier to arrange the second tube 2 around the second portion 3P2, as shown in Figure 7.

[0036] As shown in Figure 4, it is preferable that the adhesive 3 has a third portion 3P3 located distal to the second portion 3P2 and having a wall thickness in the radial direction 1D that is greater than that of the second portion. The thickness of the third portion 3P3 improves the fixing strength against external forces in the radial direction 1D.

[0037] As shown in Figures 2 and 6, it is preferable that the proximal end 3a of the adhesive 3 is exposed. This allows the thickness of the proximal end 3a of the adhesive 3 to be increased, thereby further improving the fixing strength.

[0038] As shown in Figure 2, the second tube 2 has a molten surface 2M in the portion in contact with the adhesive 3. In Figure 2, the general shape of the molten surface 2M is shown as a roughly mountain-like shape, but the detailed shape of the molten surface 2M is usually an irregular shape, such as an irregular curved surface or an irregular uneven surface, as shown in Figures 7 and 8. The fact that the second tube 2 has an irregularly shaped molten surface 2M improves the durability against multidirectional forces at the fixing portion between the tubes.

[0039] The molten surface 2M of the second tube 2 can be formed, for example, by providing a cut surface 1C on the multi-lumen tube that will become the first tube 1, applying adhesive 3 to at least a part of the cut surface 1C to form an amorphous portion of the adhesive 3, and then covering at least a part of the amorphous portion of the adhesive 3 with the single-lumen tube that will become the second tube 2, and then heating and melting the single-lumen tube. For details, refer to the description of the method of fixing the first tube 1 and the second tube 2 with adhesive 3, which will be described later.

[0040] Preferably, the second tube 2 has a recess 2D that is recessed from the proximal side to the distal side in the portion in contact with the adhesive 3. The fixing strength is further improved by fixing the convex portion 1H of the first tube 1 and the recess 2D of the second tube 2 via the adhesive 3. The recess 2D of the second tube 2 can be formed by applying adhesive 3 to the convex portion 1H formed by cutting the multi-lumen tube that will become the first tube 1 to form a convex portion of the adhesive 3, and then covering at least the convex portion of the adhesive 3 with the single-lumen tube that will become the second tube 2 and heating and melting the single-lumen tube. For details, refer to the description of the method of fixing the first tube 1 and the second tube 2 with adhesive 3 which will be described later.

[0041] As shown in FIGS. 2 and 7, it is preferable that the proximal end portion 2a of the second tube 2 is in contact with the adhesive 3. Thereby, the fixing strength in the longitudinal direction 1X of the first tube 1 and the second tube 2 can be improved. At the proximal end portion 2a of the second tube 2, it is preferable that at least the inner surface and the proximal end face of the second tube 2 are in contact with the adhesive 3. Thereby, the fixing strength is improved.

[0042] It is preferable that the second tube 2 and the first tube 1 are not in contact with each other. Thereby, since the contact area between each tube and the adhesive 3 can be increased, the fixing strength is further improved.

[0043] The second tube 2 preferably has a lower Shore D hardness than the first tube 1. Thereby, the portion of the second tube 2 can be easily curved by the operation of the endoscope. The Shore D hardness can be measured using a type D durometer, for example, based on the description in JIS K6253-2:2012.

[0044] The second tube 2 preferably contains a second resin. The second resin preferably has a lower melting point than the resin of the first tube 1. Thereby, since the tube serving as the second tube 2 can be easily heated and melted, it becomes easier to fix the second tube 2 to the first tube 1.

[0045] The second resin is preferably a thermoplastic resin. This makes it easier to heat and melt the tube that will form the second tube 2. The second resin may include, for example, polyamide; polyimide; polyamide-imide; polyurethane; rubber such as silicone rubber; elastomers such as polyolefin elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer, fluoroelastomer; polyester such as polyethylene terephthalate; polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer; or a combination thereof. The second resin preferably contains elastomer, polyurethane, rubber, or a combination thereof, more preferably contains elastomer, and more preferably contains polyamide elastomer. This makes it easier to bend the portion of the second tube 2 by manipulating the endoscope.

[0046] The second tube 2 may contain the second resin and additives. The additives may include, for example, fillers, colorants, plasticizers, lubricants, antistatic agents, flame retardants, antioxidants, UV absorbers, hydrolysis inhibitors, or mixtures thereof.

[0047] As shown in Figure 1, the endoscope 91 according to the embodiment preferably has a shaft 4 and a connector 5 fixed directly or indirectly to the proximal end 4a of the shaft 4. The shaft 4 preferably has a first tube 1, a second tube 2, and an adhesive 3.

[0048] Although not shown, the endoscope 91 may have an outer tube that covers the outer surfaces of the first tube 1, the adhesive 3, and the second tube 2. In this case, the outer tube only needs to cover at least a part of the outer surfaces of the first tube 1, the adhesive 3, and the second tube 2. The outer tube may include polyester such as polyethylene terephthalate; polyolefin such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer; polyamide; polyimide; polyamideimide; polyurethane; rubber such as silicone rubber; elastomer such as polyolefin elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer; fluororesin; or a combination thereof.

[0049] Although not shown, the endoscope 91 may or may not have a reinforcing layer between the first tube 1 and the outer tube. The reinforcing layer preferably includes a braided body. The braided body can enhance the rigidity and make it easier to push the first tube 1 into the body. Examples of the braided body include those formed by braiding single wires or stranded wires in a specific pattern into a cylindrical shape. Examples of the materials for the single wires and stranded wires include metals such as stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, tungsten alloy, and synthetic resins such as polyarylate-based resin, aramid-based resin, and polyolefin-based resin such as ultra-high molecular weight polyethylene. These may be used alone or in combination of two or more.

[0050] The length of the first tube 1 in the longitudinal direction 1X is preferably 50 to 300 cm, and more preferably 150 to 250 cm. The length of the second tube 2 in the longitudinal direction 1X is preferably shorter than the length of the first tube 1 in the longitudinal direction 1X. The length of the second tube 2 in the longitudinal direction 1X is preferably 1 to 20 cm, and more preferably 2 to 5 cm. If the adhesive 3 is exposed between the first tube 1 and the second tube 2, the length of the exposed portion of the adhesive 3 in the longitudinal direction 1X is preferably 0.1 to 1.0 cm, and more preferably 0.2 to 0.5 cm. The lengths in the radial direction 1D of the first tube 1, the adhesive 3, and the second tube 2 are preferably 1 mm or more and 10 mm or less, and more preferably 2 mm or more and 6 mm or less, respectively. This allows for suitable use in an endoscope.

[0051] As shown in Figures 4 and 8, it is preferable that the adhesive 3 has multiple lumens 3L that communicate with multiple lumens 1L of the first tube 1 and extend in the longitudinal direction 1X. As shown in Figures 2 and 9, it is preferable that the second tube 2 has multiple lumens 2L that communicate with multiple lumens 3L of the adhesive 3 and extend in the longitudinal direction 1X. By having the multiple lumens 1L, multiple lumens 3L, and multiple lumens 2L communicate in sequence in this way, multiple lumens 4L of the shaft 4 can be formed.

[0052] In a cross-section perpendicular to the longitudinal direction 1X, the shapes of the multiple lumens 4L are preferably circular or elliptical. This makes it easier to insert each member into each lumen. The shapes of the multiple lumens 1L, multiple lumens 2L, and multiple lumens 3L described above are also preferably circular or elliptical in a cross-section perpendicular to the longitudinal direction 1X.

[0053] As shown in Figures 5 to 9, the multiple lumens 4L of the shaft 4 include a first lumen 11L and a second lumen 12L, and it is preferable that the second lumen 12L has a larger diameter than the first lumen 11L. This allows the second lumen 12L to be used as a lumen for inserting a treatment instrument such as forceps, and the first lumen 11L to be suitable as a lumen in which wiring W1 for transmitting image information is arranged. Although not shown, it is preferable that an image sensor is connected to the distal end of the wiring W1 for transmitting image information. This allows image information obtained from the image sensor to be transmitted to the proximal side. Examples of image sensors include CMOS and CCD. Examples of wiring W1 for transmitting image information include electric wires and optical fibers. It is preferable that the electric wire has an insulating film. A relay lens may be placed in place of the wiring W1 for transmitting image information in the first lumen 11L of the shaft 4.

[0054] As shown in Figures 5 to 9, the multiple lumens 4L of the shaft 4 preferably include a third lumen 13L, and the third lumen 13L preferably has a smaller diameter than the first lumen 11L. This makes the third lumen 13L suitable as a lumen in which the operating wire W2 is positioned. Although not shown, it is preferable that the distal end of the operating wire W2 is fixed to a ring. By fixing the ring to, for example, a portion of the second tube 2 of the shaft 4 and operating the operating wire W2 from the proximal side, a part of the shaft 4 can be bent. The multiple lumens 4L of the shaft 4 preferably include two to eight third lumens 13L, and more preferably four to six. The endoscope 91 preferably has two to eight operating wires W2, and more preferably four to six. The operating wire W2 may be a single wire or a stranded wire, and may contain metals such as stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, or tungsten alloy, synthetic resins such as polyarylate resins, aramid resins, or polyolefin resins such as ultra-high molecular weight polyethylene, or a combination thereof.

[0055] Although not shown in the diagram, the multiple lumens 4L of the shaft 4 may further include a fourth lumen. The fourth lumen is preferably smaller in diameter than the first lumen 11L. This makes the fourth lumen suitable as a lumen in which wiring for a lighting fixture is arranged. The distal end of the wiring for the lighting fixture is preferably connected to a lighting fixture. The lighting fixture preferably has a light-emitting diode (LED). Examples of wiring for the lighting fixture include electric wires and optical fibers. Furthermore, the electric wire is preferably insulated. The multiple lumens 4L of the shaft 4 preferably include one to four fourth lumens, and more preferably two.

[0056] Although not shown in the diagram, the multiple lumens 4L of the shaft 4 may further include a fifth lumen. The fifth lumen is preferably smaller in diameter than the first lumen 11L. This makes the fifth lumen suitable as a passage for liquids such as saline solution or medicinal solutions. The multiple lumens 4L of the shaft 4 preferably include one fifth lumen.

[0057] The number of multiple lumens 4L of the shaft 4 may be 2 or more, 4 or more, or 6 or more, and may be 14 or less, 12 or less, or 10 or less.

[0058] As shown in Figures 1 and 10, the endoscope 91 preferably has a tip 9T at the distal end of the shaft 4. In this case, it is preferable that an image sensor, an illumination device, or both are arranged inside the tip 9T. It is preferable that the tip 9T has an objective lens 9G. It is preferable that the tip 9T has an aperture 9H for treatment instruments, which will be described later. In addition, the tip 9T may have an illumination lens.

[0059] In Figure 1, a connector 5 is fixed to the proximal end 4a of the shaft 4 via a branching tube 20. Preferably, the connector 5 has a first hole 5L1 communicating with the distal opening 5G3 and the first proximal opening 5G1, and a second hole 5L2 communicating with the second proximal opening 5G2 and the first hole 5L1. This makes it easier to position the branching portion of the branching tube 20 inside the connector 5. Preferably, the branching tube 20 has multiple lumens extending along the first hole 5L1, the second hole 5L2, or both. The branching tube 20 may also be constructed by joining two or more tubes together.

[0060] It is preferable that the first hole 5L1 of the connector 5 communicates with the first lumen 11L and the third lumen 13L of the shaft 4. This allows the wiring W1 for transmitting video information, the operating wire W2, etc., to be exposed from the first proximal opening 5G1 of the connector 5. As a result, although not shown, the proximal end of the wiring W1 for transmitting video information can be connected to a video display device, and the operating wire W2 can be connected to the operating part of the handle. The handle only needs to be configured so that the user can grip it. The operating part may be a cylindrical body that can rotate in the circumferential direction, or it may be a dial. The operating part may also have a rotating mechanism such as a pulley or sprocket.

[0061] It is preferable that the second hole 5L2 of the connector 5 and the second lumen 12L of the shaft 4 are in communication. This allows a treatment instrument such as forceps to be inserted from the second proximal opening 5G2 of the connector 5 into the second lumen 12L of the shaft 4, and the treatment instrument to be exposed from the treatment instrument opening 9H of the tip 9T at the distal end of the shaft 4, allowing the treatment to be performed. It is preferable that the connector 5 is a molded body made of resin.

[0062] The endoscope 91 according to this embodiment is preferably capable of observing, for example, the digestive tract such as the esophagus, stomach, small intestine, and large intestine; blood vessels such as coronary arteries; respiratory organs such as the thoracic cavity and bronchi; urinary organs such as the bladder and renal pelvis; pancreas; biliary tract; etc. The endoscope 91 may also be a disposable endoscope. This can prevent infection of the person being observed.

[0063] The following describes an example of a method for fixing the first tube 1 and the second tube 2 with adhesive 3. For example, a cut surface 1C is provided at the distal end of the multi-lumen tube that will become the first tube 1, and then multiple core materials are arranged in the multi-lumen so that at least the distal ends of the multiple core materials are exposed. Next, adhesive 3 is applied to at least a part of the cut surface 1C and to the multiple core materials. Next, a single-lumen tube that will become the second tube 2 is positioned so that its proximal end is in contact with the adhesive 3, and these are covered with heat-shrink tubing and then heated. Heating is continued until the heat-shrink tubing shrinks and the single-lumen tube melts and fills the gaps between the multiple core materials. After cooling, the multiple core materials are removed and the heat-shrink tubing is removed to form a shaft 4 having the first tube 1, the second tube 2, and the adhesive 3 that fixes them together.

[0064] When the single-lumen tube that will become the second tube 2 is melted by heating, the adhesive 3 does not need to be solidified yet, and may be fully solidified, but it is preferable that it is solidified. If the adhesive 3 is not fully solidified, for example, the shape of the outer surface of the adhesive 3 can be adjusted when the single-lumen tube is heated. On the other hand, if the adhesive 3 is solidified, excessive flow of the adhesive 3 can be prevented during heating, reducing the possibility of the resin of the single-lumen tube flowing into the adhesive 3. As a result, the resin of the second tube 2 and the first tube 1 are less likely to come into contact, and the fixing strength is further improved. The method for manufacturing the endoscope according to the embodiment will be described in more detail below.

[0065] The method for manufacturing an endoscope according to this embodiment includes the steps of: cutting the distal end of a first tube having a plurality of lumens extending in the longitudinal direction to provide a cut portion; arranging a plurality of core materials in the plurality of lumens so that the distal ends of the plurality of core materials are exposed; applying adhesive to the cut portion; arranging a second tube so that its proximal end contacts the adhesive; and melting the second tube by heating. By cutting the distal end of the first tube as described above, the contact area between the first tube and the adhesive can be increased, thereby improving the adhesive strength. Furthermore, by bringing the proximal end of the second tube into contact with the adhesive and melting the second tube by heating, an irregularly shaped molten surface is formed in the part of the second tube that is in contact with the adhesive, thereby improving the durability against multidirectional forces at the fixing portion between the tubes. These combined effects can improve the fixing strength between the tubes. In particular, improving the fixing strength between the tubes in the part inserted into the body enhances safety. Hereinafter, the method for manufacturing an endoscope according to this embodiment may be simply referred to as the manufacturing method of this embodiment.

[0066] The following describes the method for manufacturing an endoscope according to the embodiment, with reference to each figure, but first, the method for manufacturing the shaft portion will be described. Figure 11 is a side view of the first tube in the manufacturing process of the endoscope according to the embodiment. Figure 12 is a side view of the first tube of Figure 11 when a cut portion is provided. Figure 13 is a side view of the first tube of Figure 12 when multiple core materials are placed in multiple lumens. Figure 14 is a side view when the core materials are covered with a resin tube. Figure 15 is a side view of the first tube of Figure 13 when adhesive is applied to the cut portion. Figure 16 is a side view of the second tube of Figure 15 when it is placed in contact with the adhesive. Figure 17 is a side view of the first tube, adhesive, and second tube of Figure 16 when they are covered with a heat shrink tube. Figure 18 is a side view of the second tube of Figure 17 when it is melted by heating. Figure 19 is a side view of the shaft formed by removing the heat shrink tube and multiple core materials of Figure 18. In Figure 16, the second tube is shown in a longitudinal cross-sectional view to make its position easier to understand, and therefore the second tube appears semi-cylindrical. In Figure 17, the second tube and the heat-shrinkable tube are shown in longitudinal cross-sectional views to make their positions easier to understand, and therefore they each appear semi-cylindrical.

[0067] As shown in Figure 11, the first tube 1 used in the manufacture of the endoscope has a plurality of lumens 1L extending in the longitudinal direction 1X. As shown in Figures 11 and 12, the manufacturing method of the embodiment includes a step of cutting the distal end 1b of the first tube 1 to provide a cut portion 1C1. By providing a cut portion 1C1 on the first tube 1, the contact area between the adhesive 3 (described later) and the first tube 1 can be increased. When cutting the distal end 1b of the first tube 1 to provide a cut portion 1C1, a cutter, grinder, or the like can be used to remove a portion of the distal end 1b.

[0068] The first tube 1 preferably contains a first resin. The first resin is preferably a thermoplastic resin. This makes it easier to mold the first tube 1 before cutting by extrusion molding or the like. The first resin may contain, for example, fluororesin; polyester such as polyethylene terephthalate; polyolefin such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer; polyamide; polyimide; polyamide-imide; polyurethane; rubber such as silicone rubber; elastomer such as polyolefin elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer; or a combination thereof. The fluororesin preferably contains polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, or a combination thereof. The first resin preferably contains fluororesin, and more preferably contains polytetrafluoroethylene.

[0069] Preferably, the first tube 1 contains fluororesin in at least a portion of the part that comes into contact with the multiple lumens 1L. This improves the sliding properties of the members inserted into the multiple lumens 1L.

[0070] Preferably, the first tube 1 contains fluororesin in at least a portion of its outer surface. This improves insertability when the first tube 1 is inserted into the body with at least a portion exposed. Preferably, the outer surface of the first tube 1 does not have grooves. This further improves insertability when the first tube 1 is inserted into the body with at least a portion exposed.

[0071] The first tube 1 is preferably made of a fluororesin. Specifically, the first tube 1 being made of a fluororesin means that it contains fluororesin in an amount of 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. In addition to the fluororesin, the first tube 1 may also contain additives. The additives may include, for example, fillers, colorants, plasticizers, lubricants, antistatic agents, flame retardants, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, or mixtures thereof.

[0072] In a cross-section perpendicular to the longitudinal direction 1X of the first tube 1, the shapes of the multiple lumens 1L are preferably circular or elliptical. This facilitates the insertion of each component into the first tube 1. For details on the use and shape of the multiple lumens 1L, please refer to the description of the multiple lumens 4L of the shaft 4, which will be described later.

[0073] Although not shown in the figures, the first tube 1 may have a plurality of inner layers that are in contact with a plurality of lumens 1L, and an outer layer that covers the plurality of inner layers. In this case, the plurality of inner layers may contain the fluororesin exemplified as the first resin, and the outer layer may contain a resin other than the fluororesin among the resins exemplified as the first resin.

[0074] As shown in Figure 12, it is preferable that the cut portion 1C1 has a protrusion 1H that extends from the proximal side toward the distal side. By forming such a protrusion 1H on the first tube 1 by cutting, the adhesive 3 can adhere more easily to the first tube 1.

[0075] The shape of the protrusion 1H is preferably a cylinder, a frustocone, a polygonal prism, a frustocone, or a combination thereof, and more preferably a cylinder, a frustocone, or a combination thereof. This makes it less likely for the protrusion 1H to be damaged by external forces. These shapes are as shown in the side view in Figure 12.

[0076] Preferably, the protrusion 1H has an unmachined distal end face 1H2 and a machined outer surface 1H1 extending in the circumferential direction 1Y. In Figure 12, the distal end face 1H2 is oriented from the proximal to the distal direction in the longitudinal direction 1X of the first tube 1, and the outer surface 1H1 is oriented from the inside to the outside in the radial direction 1D of the first tube 1. By applying adhesive 3 to these surfaces, the fixing strength in the longitudinal direction 1X and the radial direction 1D is improved. Also, because the distal end face 1H2 of the protrusion 1H is unmachined, the strength of the protrusion 1H is more easily maintained. Preferably, the distal end face 1H2 of the protrusion 1H is flat. On the other hand, preferably, the shape of the outer surface 1H1 of the protrusion 1H is curved. Being curved improves the strength of the protrusion 1H against external forces in the radial direction 1D.

[0077] The convex portion 1H preferably has a tapered portion 1H3 in which the outer diameter decreases from the proximal side to the distal side. Even if interfacial delamination occurs between the convex portion 1H and the adhesive 3 due to kinking during insertion into the body, the tapered portion 1H3 can suppress the propagation of delamination in the longitudinal direction 1X. Furthermore, since the adhesive 3 can be applied thickly near the tapered portion 1H3, the fixing strength is further improved. The tapered portion 1H3 preferably has a curved surface. Being a curved surface improves the strength of the tapered portion 1H3 against external forces in the radial direction 1D. Although not shown, the convex portion 1H may also have a tapered portion in which the outer diameter decreases from the distal side to the proximal side. In this case, the second tube 2 becomes less likely to detach from the first tube 1 when the first tube 1 is pulled back.

[0078] The cutting portion 1C1 preferably has a base surface 1Cs that is oriented from the proximal to the distal direction in the longitudinal direction 1X. This further increases the contact area between the first tube 1 and the adhesive 3 and improves the fixing strength in the longitudinal direction 1X. The shape of the base surface 1Cs is preferably an annular plane. This makes it easier for the adhesive 3 to adhere around the convex portion 1H.

[0079] The cutting portion 1C1 may have multiple cutting surfaces. In this case, it is preferable that adjacent cutting surfaces are in contact with each other. For example, in the embodiment shown in Figure 12, the base surface 1Cs and the outer surface 1H1 are in contact, and the outer surface 1H1 and the cutting surface of the tapered portion 1H3 are in contact. Such multiple contacting cutting surfaces can be formed, for example, by continuously cutting the distal end 1b of the first tube 1 in multiple directions.

[0080] As shown in Figure 13, the manufacturing method of the embodiment includes the step of arranging multiple core materials R in multiple lumens 1L of the first tube 1 such that the distal ends Rb of the multiple core materials R are exposed. Exposure of the distal ends Rb of the multiple core materials R means that at least the distal ends Rb are exposed from the first tube 1; for example, the distal portions of the multiple core materials R may be exposed from the first tube 1. Inserting the core materials R into the multiple lumens 1L prevents deformation of the lumens. Furthermore, by leaving a portion of the core materials R exposed from the first tube 1, multiple lumens communicating with the multiple lumens 1L can be formed, as will be described later. The core material R is preferably a mandrel. It is preferable to insert the core materials R into all of the multiple lumens 1L, but the core materials R may be inserted into some of the lumens 1L. The core material R is preferably cylindrical or elliptical, and may have a tapered portion where the outer diameter decreases toward the distal or proximal side.

[0081] As shown in Figure 14, the manufacturing method of the embodiment may include a step of covering each of the multiple core materials R with a resin tube T before the step of arranging the multiple core materials R in the multiple lumens 1L. When using an adhesive 3 with components that readily adhere to the core materials R, the core materials R can be easily removed by using a resin tube T to which the adhesive 3 does not readily adhere. The resin tube T preferably contains, for example, a fluororesin. The fluororesin preferably contains polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, or a combination thereof, and more preferably contains polytetrafluoroethylene.

[0082] As shown in Figure 15, the manufacturing method of the embodiment includes the step of applying adhesive 3 to the cut portion 1C1. It is sufficient to apply adhesive 3 to at least a part of the cut portion 1C1, but it is preferable to apply adhesive 3 to the entire cut portion 1C1. Furthermore, it is preferable to apply adhesive 3 to the portion adjacent to the cut portion 1C1, for example, the distal end face 1H2 of the convex portion 1H. This improves the fixing strength. When applying adhesive 3 to the cut portion 1C1, it is possible to apply the adhesive 3 by, for example, coating or dripping. In this case, it is preferable to apply adhesive 3 to multiple core materials R or resin tubes T. This makes it easier to form multiple lumens 3L of the adhesive 3, which will be described later. In Figure 15, the general shape of the adhesive 3 is shown as a roughly mountain shape, but the detailed shape of the exposed surface of the adhesive 3 is usually an irregular shape, such as an irregular curved shape or an irregular uneven shape, as shown in Figure 21, which will be described later.

[0083] Adhesive 3 preferably contains an epoxy resin. The epoxy resin improves the tensile strength between tubes. The epoxy resin preferably contains bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, or a combination thereof. Adhesive 3 preferably further contains a curing component. The curing component preferably contains polyamine compounds such as aliphatic polyamines, aromatic amines, polyamidoamines, and polyether polyamines; phenol compounds such as novolac, cresol novolac, and bisphenol A type novolac; acid anhydrides such as tetrahydro phthalic anhydride and hexahydro phthalic anhydride; dicyandiamide compounds; imidasol compounds; polythiol compounds; or a combination thereof. Adhesive 3 may further contain additives such as catalysts, fillers, colorants, plasticizers, lubricants, antistatic agents, flame retardants, antioxidants, UV absorbers, hydrolysis inhibitors, or mixtures thereof to promote the curing reaction.

[0084] The adhesive 3 is not limited to epoxy adhesives, but may also be, for example, a urethane adhesive, a cyanoacrylate adhesive, or a silicone adhesive.

[0085] Adhesive 3 is preferably a room-temperature curing type or a heat-curing type, and more preferably a room-temperature curing type. In the case of a room-temperature curing type, as described later, the second tube 2 can be heated and melted after the adhesive 3 has cured to a certain extent. Adhesive 3 may be a one-component, two-component, or three-component adhesive, but it is preferably a two-component or three-component adhesive.

[0086] Although not shown in the figures, the manufacturing method of the embodiment may include a step of hydrophilizing the cut portion 1C1 before the step of applying the adhesive 3. For example, if the cut portion 1C1 contains polytetrafluoroethylene and the adhesive 3 contains epoxy resin, hydrophilizing the adhesive 3 makes it easier for the adhesive 3 to adhere to the cut portion 1C1. Examples of hydrophilizing treatments include tetraetch treatment, fluorobonder treatment, and plasma treatment, with tetraetch treatment being preferred. Examples of hydrophilizing agents include tetraetch® and fluorobonder®, which are effective when hydrophilizing fluororesins. Furthermore, by plasma treatment, hydrophilic groups can be imparted to resins other than fluororesins, allowing for hydrophilization treatment. When performing hydrophilization treatment, it is also preferable to perform hydrophilization treatment on the portion adjacent to the cut portion 1C1, for example, the distal end face 1H2 of the convex portion 1H.

[0087] As shown in Figure 16, the manufacturing method of the embodiment includes the step of positioning the second tube 2 such that its proximal end 2a contacts the adhesive 3. This improves the fixing strength of the first tube 1 and the second tube 2 in the longitudinal direction 1X. In this case, it is preferable that at least the inner surface and the proximal end surface of the second tube 2 are in contact with the adhesive 3 at the proximal end 2a of the second tube 2. This improves the fixing strength.

[0088] In the process of arranging the materials, it is preferable that the second tube 2 has a lumen extending in the axial direction of the second tube 2. It is preferable that at least a portion of the protrusion 1H of the cut portion 1C1 is arranged in the lumen. This improves the fixing strength of the second tube 2 after heating and melting. Furthermore, it is preferable that a portion of the longitudinal direction 1X of the multiple core materials R is arranged in the lumen. This makes it possible to form multiple lumen 2L, which will be described later.

[0089] In the process of arranging the materials, it is preferable that the second tube 2 has only one lumen extending in the axial direction of the second tube 2. This makes it easier to arrange at least a portion of the protrusion 1H of the cut portion 1C1, a portion of the multiple core materials R in the longitudinal direction 1X, and at least a portion of the adhesive 3 inside the second tube 2.

[0090] As shown in Figure 16, in the process of positioning the second tube 2, it is preferable to position the second tube 2 such that the proximal end 3a of the adhesive 3 is exposed. This allows the wall thickness of the proximal end 3a of the adhesive 3 to be increased, thereby further improving the fixing strength.

[0091] The manufacturing method of this embodiment includes a step of melting the second tube 2 by heating. By melting the second tube 2 by heating, the gaps between the multiple core materials R can be filled with the second tube 2. Furthermore, by melting the second tube 2 by heating, an irregularly shaped molten surface can be formed in the portion that comes into contact with the adhesive 3.

[0092] When the second tube 2 is melted by heating, the adhesive 3 may not be fully solidified, or it may be fully solidified, but it is preferable that it is fully solidified. If the adhesive 3 is not fully solidified, for example, the shape of the outer surface of the adhesive 3 can be adjusted when the second tube 2 is heated. On the other hand, if the adhesive 3 is fully solidified, excessive flow of the adhesive 3 during heating can be prevented, reducing the possibility of the resin of the second tube 2 flowing into the adhesive 3. As a result, it becomes more difficult for the resin of the second tube 2 to come into contact with the first tube 1, further improving the fixing strength.

[0093] The second tube 2 preferably contains a second resin with a lower melting point than the resin of the first tube 1. This makes it possible to maintain the shape of the cut portion 1C1 of the first tube 1 during heating while making it easier to melt the second tube 2 by heating.

[0094] The second resin is preferably a thermoplastic resin. This makes it easier to heat and melt the second tube 2 to fill the gaps between the multiple core materials R. The second resin may include, for example, polyamide; polyimide; polyamide-imide; polyurethane; rubber such as silicone rubber; elastomers such as polyolefin elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer, fluoroelastomer; polyester such as polyethylene terephthalate; polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer; or a combination thereof. The second resin preferably contains elastomer, polyurethane, rubber, or a combination thereof, more preferably contains elastomer, and more preferably contains polyamide elastomer. This makes it easier to bend the portion of the second tube 2 by manipulating the endoscope.

[0095] The second tube 2 may contain the second resin and additives. The additives may include, for example, fillers, colorants, plasticizers, lubricants, antistatic agents, flame retardants, antioxidants, UV absorbers, hydrolysis inhibitors, or mixtures thereof.

[0096] In the step of melting the second tube 2 by heating, the heating temperature is preferably above the melting point of the second resin and below the melting point of the second resin + 100°C, and more preferably above the melting point of the second resin + 20°C and below the melting point of the second resin + 80°C. The heating time is preferably 1 minute or more and 30 minutes or less, and more preferably 2 minutes or more and 10 minutes or less.

[0097] As shown in Figure 17, the manufacturing method of the embodiment preferably includes a step of covering the first tube 1, adhesive 3, and second tube 2 with a heat-shrinkable tube S after the step of applying the adhesive 3 and before the step of melting the second tube 2 by heating. By arranging the first tube 1, adhesive 3, and second tube 2 inside the lumen of the heat-shrinkable tube S, it becomes easier to prevent the occurrence of irregularities on their surfaces after the second tube 2 is heated and melted. It is preferable that the heat-shrinkable tube S has only one lumen extending in the axial direction of the heat-shrinkable tube S. This makes it easier to arrange at least a part of each component inside the heat-shrinkable tube S.

[0098] The heat-shrinkable tube S preferably contains polyamide; polyurethane; rubber such as silicone rubber; polyester; polyolefin such as polyethylene or polypropylene; fluororesin; or a combination thereof. The heat-shrinkable tube S preferably shrinks when heated at 40 to 250°C, and more preferably shrinks when heated at 60 to 180°C.

[0099] In Figure 18, the second tube 2 melts upon heating, filling the gaps between the multiple core materials R, and the outer surface of the melted second tube 2 becomes smooth due to the shrinkage of the heat-shrinkable tube S. Thus, heating should be stopped after the second tube 2 has melted and the heat-shrinkable tube S has shrunk, and then the process should be cooled by air cooling or other means.

[0100] As shown in Figure 15, when the adhesive 3 is applied to the entire protrusion 1H of the first tube 1, a convex portion is formed on the adhesive 3. Furthermore, as shown in Figures 18 and 19, when the convex portion of the adhesive 3 is covered with the second tube 2 and heated and melted, a recess 2D is formed on the second tube 2. The fixing strength is further improved because the recess 2D formed in this way and the protrusion 1H are fixed via the adhesive 3.

[0101] As shown in Figure 19, the manufacturing method of the embodiment preferably includes a step of removing the heat-shrinkable tube S. This allows the outer surfaces of the first tube 1, adhesive 3, and second tube 2 to be exposed, and these outer surfaces can be further covered with an outer tube if necessary. In this case, the outer tube only needs to cover at least a portion of the outer surfaces of the first tube 1, adhesive 3, and second tube 2. The outer tube may contain polyester such as polyethylene terephthalate; polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer; polyamide; polyimide; polyamide-imide; polyurethane; rubber such as silicone rubber; elastomers such as polyolefin elastomer, polyester elastomer, polyamide elastomer, and polyurethane elastomer; fluororesin; or a combination thereof.

[0102] Furthermore, a reinforcing layer may or may not be placed between the first tube 1 and the outer tube as needed. The reinforcing layer preferably includes a braided body. The braided body can increase rigidity and make it easier to push the first tube 1 into the body. Examples of braided bodies include those made by braiding single or stranded wires into a cylindrical shape in a specific pattern. Examples of single and stranded wire materials include metals such as stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, and tungsten alloy, and synthetic resins such as polyarylate resins, aramid resins, and polyolefin resins such as ultra-high molecular weight polyethylene. These may be used individually or in combination of two or more types.

[0103] As shown in Figure 19, the manufacturing method of the embodiment preferably includes a step of removing a plurality of core materials R. This makes it possible to form a plurality of lumens communicating with a plurality of internal lumens 1L in each of the second tube 2 and the adhesive 3. It is preferable to remove the plurality of core materials R after the step of removing the heat shrink tube S. This makes it easier to maintain the shape of each internal lumen.

[0104] As shown in Figures 19 and 21, after the step of melting the second tube 2 by heating, it is preferable that the adhesive 3 has a plurality of lumens 3L that communicate with a plurality of lumens 1L and extend in the longitudinal direction 1X. This allows, for example, a treatment instrument such as forceps to be inserted from inside the first tube 1 into the adhesive 3.

[0105] As shown in Figure 22, after the step of melting the second tube 2 by heating, it is preferable that the second tube 2 has a plurality of lumens 2L that communicate with a plurality of lumens 3L of the adhesive 3 and extend in the longitudinal direction 1X. This allows, for example, a treatment instrument such as forceps to be inserted from inside the adhesive 3 into the second tube 2.

[0106] As described above, by fixing the first tube 1 and the second tube 2 via adhesive 3, a shaft 4 as shown in Figure 19 can be formed. The length of the first tube 1 in the longitudinal direction 1X is preferably 50 to 300 cm, and more preferably 150 to 250 cm. The length of the second tube 2 in the longitudinal direction 1X is preferably shorter than the length of the first tube 1 in the longitudinal direction 1X. The length of the second tube 2 in the longitudinal direction 1X is preferably 1 to 20 cm, and more preferably 2 to 5 cm. If the adhesive 3 is exposed between the first tube 1 and the second tube 2, the length of the exposed portion of the adhesive 3 in the longitudinal direction 1X is preferably 0.1 to 1.0 cm, and more preferably 0.2 to 0.5 cm. The radial lengths 1D of the first tube 1, the adhesive 3, and the second tube 2 are preferably 1 mm or more and 10 mm or less, and more preferably 2 mm or more and 6 mm or less, respectively. This makes it suitable for use in an endoscope.

[0107] Next, the method for manufacturing the endoscope according to the embodiment will be described in more detail with reference to each figure. Figure 20 is a cross-sectional view taken along the line XX-XX of Figure 19. Figure 21 is a cross-sectional view taken along the line XXI-XXI of Figure 19. Figure 22 is a cross-sectional view taken along the line XXII-XXII of Figure 19. Figure 23 is a cross-sectional view taken along the line XX-XX of the shaft of Figure 19, showing the arrangement of operating wires and wiring for transmitting image information in multiple lumens. Figure 24 is a side view of the endoscope according to the embodiment. Figure 25 is a view showing the distal end face of the endoscope of Figure 24.

[0108] As shown in Figures 19 and 20, the shaft 4 used in the manufacture of the endoscope 92 of the embodiment shown in Figure 24 preferably has a plurality of lumens 4L extending in the longitudinal direction 1X. As shown in Figure 20, in a cross-section perpendicular to the longitudinal direction 1X of the shaft 4, the shapes of the plurality of lumens 4L are preferably circular or elliptical. This makes it easier to insert each component into the shaft 4. The shapes of the plurality of lumens 1L, plurality of lumens 2L, and plurality of lumens 3L described above are also preferably circular or elliptical in a cross-section perpendicular to the longitudinal direction 1X.

[0109] As shown in Figure 20, the multiple lumens 4L of the shaft 4 include a first lumen 11L and a second lumen 12L, and it is preferable that the second lumen 12L has a larger diameter than the first lumen 11L. This allows, for example, the second lumen 12L to be used as a lumen for inserting a treatment instrument such as forceps, and as shown in Figure 23, the first lumen 11L becomes suitable as a lumen for arranging wiring W1 for transmitting video information.

[0110] As shown in Figure 20, the multiple lumens 4L of the shaft 4 preferably include a third lumen 13L, and the third lumen 13L preferably has a smaller diameter than the first lumen 11L. As a result, as shown in Figure 23, the third lumen 13L is suitable as a lumen for positioning the operating wire W2. The shaft 4 preferably has two to eight third lumens 13L, and more preferably four to six.

[0111] Although not shown in the diagram, the multiple lumens 4L of the shaft 4 may further have a fourth lumen. The fourth lumen is preferably smaller in diameter than the first lumen 11L. This makes the fourth lumen suitable for arranging wiring for lighting fixtures. The shaft 4 preferably has one to four fourth lumens, and more preferably two.

[0112] Although not shown in the diagram, the multiple lumens 4L of the shaft 4 may further have a fifth lumen. The fifth lumen is preferably smaller in diameter than the first lumen 11L. This makes the fifth lumen suitable as a passage for liquids such as physiological saline or medicinal solutions. The shaft 4 is preferably having one fifth lumen.

[0113] The number of multiple lumens 4L of the shaft 4 may be 2 or more, 4 or more, or 6 or more, and may be 14 or less, 12 or less, or 10 or less.

[0114] As shown in Figure 23, the manufacturing method of the embodiment preferably includes the step of arranging wiring W1 for transmitting image information in the first lumen 11L of the shaft 4. It is preferable that an image sensor is connected to the distal end of the wiring W1 for transmitting image information. This allows image information obtained from the image sensor to be transmitted to the proximal side. Examples of image sensors include CMOS and CCD. Examples of wiring W1 for transmitting image information include electric wires and optical fibers. It is also preferable that the electric wire has an insulating film. Alternatively, a relay lens may be placed in the first lumen 11L of the shaft 4 instead of the wiring W1 for transmitting image information.

[0115] The manufacturing method of the embodiment preferably includes the step of placing an operating wire W2 in the third lumen 13L of the shaft 4. The distal end of the operating wire W2 is preferably fixed to a ring. By fixing the ring to, for example, a portion of the second tube 2 of the shaft 4 and operating the operating wire W2 from the proximal side, a portion of the shaft 4 can be bent. The operating wire W2 may be a single wire or a stranded wire, and may contain metals such as stainless steel, titanium, nickel-titanium alloy, cobalt-chromium alloy, tungsten alloy, synthetic resins such as polyarylate resins, aramid resins, polyolefin resins such as ultra-high molecular weight polyethylene, or a combination thereof.

[0116] Although not shown in the figures, the manufacturing method of the embodiment preferably includes the step of arranging wiring for a lighting fixture in the fourth lumen of the shaft 4. The distal end of the wiring for the lighting fixture is preferably connected to a lighting fixture. The lighting fixture preferably has a light-emitting diode (LED). Examples of wiring for the lighting fixture include electric wires and optical fibers. Furthermore, it is preferable that the electric wire has an insulating film.

[0117] As shown in Figures 24 and 25, the manufacturing method of the embodiment preferably includes the step of placing a tip 9T at the distal end of the shaft 4. In this case, it is preferable to place the tip 9T such that an image sensor, an illumination device, or both are located inside the tip 9T. It is also preferable that the tip 9T has an objective lens 9G. It is also preferable that the tip 9T has an aperture 9H for a treatment device, which will be described later. In addition, the tip 9T may have an illumination lens.

[0118] As shown in Figure 24, the manufacturing method of the embodiment preferably includes a step of fixing the connector 5 directly or indirectly to the proximal end 4a of the shaft 4. As shown in Figure 24, it is preferable to fix the connector 5 to the proximal end 4a of the shaft 4 via a branch tube 20.

[0119] The connector 5 preferably has a first hole 5L1 communicating with the distal opening 5G3 and the first proximal opening 5G1, and a second hole 5L2 communicating with the second proximal opening 5G2 and the first hole 5L1. This makes it easier to position the branch portion of the branch tube 20 inside the connector 5. The branch tube 20 preferably has multiple lumens extending along the first hole 5L1, the second hole 5L2, or both. The branch tube 20 may be constructed by joining two or more tubes.

[0120] In this case, it is preferable to fix the connector 5 so that, for example, the first hole 5L1 of the connector 5 communicates with the first lumen 11L and the third lumen 13L of the shaft 4. This allows the wiring W1 for transmitting video information, the operating wire W2, etc., to be exposed from the first proximal opening 5G1 of the connector 5. As a result, although not shown, the proximal end of the wiring W1 for transmitting video information can be connected to a video display device, and the operating wire W2 can be connected to the operating part of the handle. The handle only needs to be configured so that the user can grip it. The operating part may be a cylindrical body that can rotate in the circumferential direction, or it may be a dial. The operating part may also have a rotating mechanism such as a pulley or sprocket.

[0121] Furthermore, it is preferable to fix the connector 5 so that, for example, the second hole 5L2 of the connector 5 and the second lumen 12L of the shaft 4 are in communication. This allows a treatment instrument such as forceps to be inserted from the second proximal opening 5G2 of the connector 5 into the second lumen 12L of the shaft 4, and the treatment instrument to be exposed from the treatment instrument opening 9H of the tip 9T at the distal end of the shaft 4, thereby enabling treatment. It is preferable that the connector 5 is a molded body made of resin.

[0122] The endoscope 92 manufactured according to the above embodiment is preferably capable of observing, for example, the digestive tract such as the esophagus, stomach, small intestine, and large intestine; blood vessels such as coronary arteries; respiratory organs such as the thoracic cavity and bronchi; urinary organs such as the bladder and renal pelvis; pancreas; biliary tract; etc. The endoscope 92 may also be a disposable endoscope. This can prevent infection of the person being observed.

[0123] This application claims the benefit of priority based on Japanese Patent Application No. 2024-175344, filed on October 4, 2024, and the benefit of priority based on Japanese Patent Application No. 2024-175345, filed on October 4, 2024. The entire contents of the specifications of Japanese Patent Application No. 2024-175344 and Japanese Patent Application No. 2024-175345 are incorporated herein by reference.

[0124] 1. First tube 1b Distal end 1B Distal end 1C Cut surface 1Cs Base surface 1C1 Cut portion 1D Radial direction 1H Convex portion 1H1 Outer surface 1H2 Distal end surface 1H3 Tapered portion 1H4 Base end 1L Multiple lumens 1X Longitudinal direction 1Y Circumferential direction 2. Second tube 2B Distal end 2D Concave 2L Multiple lumens 2M Melting surface 2a Proximal end 3. Adhesive 3a Proximal end 3L Multiple lumens 3P1 First part 3P2 Second part 3P3 Third part 4. Shaft 4a Proximal end 4L Multiple lumens 5. Connector 5G1 First proximal opening 5G2 Second proximal opening 5G3 Distal opening 5L1 First hole 5L2 Second hole 9G Objective lens 9H, opening for treatment instrument 9T, tip 11L, first lumen 12L, second lumen 13L, third lumen 20, branch tubes 91, 92, endoscope R, multiple core materials Rb, distal end S, heat shrink tubing W1, wiring for image information transmission W2, operating wire

Claims

1. An endoscope comprising a first tube, a second tube whose distal end is located distal to the distal end of the first tube, and an adhesive located between the first tube and the second tube and fixing them together, wherein the first tube has at least one cut surface in the portion in contact with the adhesive, and the second tube has a molten surface in the portion in contact with the adhesive.

2. The endoscope according to claim 1, wherein the first tube has a plurality of lumens extending in the longitudinal direction of the first tube, and the adhesive has a plurality of lumens communicating with the plurality of lumens and extending in the longitudinal direction.

3. The endoscope according to claim 2, wherein the second tube has a plurality of lumens that communicate with the plurality of lumens of the adhesive and extend in the longitudinal direction.

4. The endoscope according to claim 1, wherein the first tube has a convex portion that protrudes from the proximal side toward the distal side in the portion that is in contact with the adhesive, and the second tube has a concave portion that is recessed from the proximal side toward the distal side in the portion that is in contact with the adhesive.

5. The endoscope according to claim 4, wherein the protrusion has an outer surface extending in the circumferential direction of the first tube, and at least one cutting surface includes the outer surface.

6. The endoscope according to claim 4, wherein the convex portion has an uncut distal end face.

7. The endoscope according to claim 4, wherein the convex portion has a tapered portion whose outer diameter decreases from the proximal side to the distal side.

8. The endoscope according to claim 4, wherein the adhesive has a first portion adjacent to the base end of the protrusion, and a second portion located distal to the first portion, the radial wall thickness of the first tube being thinner than that of the first portion.

9. The endoscope according to claim 8, wherein the adhesive has a third portion located distal to the second portion and having a greater radial thickness than the second portion.

10. The endoscope according to claim 1, wherein the second tube has a lower Shore D hardness than the first tube.

11. The endoscope according to claim 1, wherein the first tube comprises polytetrafluoroethylene.

12. The endoscope according to claim 11, wherein the adhesive comprises an epoxy resin and the second tube comprises an elastomer.

13. A method for manufacturing an endoscope, comprising the steps of: cutting the distal end of a first tube having a plurality of lumens extending in the longitudinal direction to provide a cut portion; arranging a plurality of core materials in the plurality of lumens such that the distal ends of the plurality of core materials are exposed; applying an adhesive to the cut portion; arranging a second tube such that its proximal end is in contact with the adhesive; and melting the second tube by heating.

14. The method for manufacturing an endoscope according to claim 13, wherein, after the step of melting the second tube by heating, the adhesive has a plurality of lumens that communicate with the plurality of lumens and extend in the longitudinal direction, and the second tube has a plurality of lumens that communicate with the plurality of lumens of the adhesive and extend in the longitudinal direction.

15. The method for manufacturing an endoscope according to claim 13, further comprising the step of covering the first tube, the adhesive, and the second tube with a heat-shrinkable tube after the step of applying the adhesive and before the step of melting the second tube by heating.

16. The method for manufacturing an endoscope according to claim 13, wherein in the step of arranging the second tube, the second tube is arranged such that the proximal end of the adhesive is exposed.

17. The method for manufacturing an endoscope according to claim 13, further comprising the step of covering each of the multiple core materials with a resin tube prior to the step of arranging the multiple core materials in the multiple lumens.

18. The method for manufacturing an endoscope according to claim 13, wherein the cutting portion has a convex portion that protrudes from the proximal side toward the distal side.

19. The method for manufacturing an endoscope according to claim 18, wherein the convex portion has an uncut distal end face and an outer surface that extends in the circumferential direction and is cut.

20. The method for manufacturing an endoscope according to claim 18, wherein the convex portion has a tapered portion whose outer diameter decreases from the proximal side to the distal side.

21. The method for manufacturing an endoscope according to claim 13, wherein the first tube comprises a first resin, and the second tube comprises a second resin having a lower melting point than the resin of the first tube.

22. The method for manufacturing an endoscope according to claim 21, wherein the first resin comprises polytetrafluoroethylene.

23. The method for manufacturing an endoscope according to claim 22, further comprising the step of performing a hydrophilic treatment on the cutting portion before the step of applying the adhesive.

24. The method for manufacturing an endoscope according to claim 21, wherein the second resin comprises an elastomer.

25. The method for manufacturing an endoscope according to claim 13, wherein the adhesive comprises an epoxy resin.

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