Endoscope bending tube, endoscope, method for manufacturing an endoscope bending tube, and bending tube for an insertion device

Abstract

This curved tube comprises: a first tubular member (12); and a second tubular member (13) which has a second tongue-piece portion (33) to be overlapped on an end of the first tubular member (12) and in which the second tongue-piece portion (33) has formed thereto a projecting portion (35) that is rotatably linked to the first tubular member (12). The end of the first tubular member (12) has formed therein a first hole (26) which penetrates said end in a radial direction of the longitudinal axis thereof and in which the projecting portion (35) is inserted. A protrusion (26c) is formed around the opening of the first hole (26). The projecting portion (35) has a second hole (34) which penetrates in the axial direction of the projecting portion (35). The second tongue-piece portion (33) has formed therein a recess (35b) that receives the protrusion (26c).

Description

【Technical Field】 【0001】 The present invention relates to a bending tube of an endoscope, an endoscope, a method for manufacturing a bending tube of an endoscope, and a bending tube of an insertion device, in which a plurality of tubular members are rotatably connected. 【Background Art】 【0002】 An endoscope can perform observation inside a subject and various treatments on the inside of the subject by inserting an insertion portion into the inside of the subject such as in a body cavity or a pipeline. 【0003】 Generally, on the distal end side of the insertion portion of an endoscope, a bending portion that can be bent in a plurality of directions is provided. In the bending portion, a bending tube provided with a plurality of bending pieces (tubular members) is widely used. The plurality of bending pieces constituting the bending tube are arranged along the longitudinal direction of the bending portion. Further, each of the adjacent bending pieces is rotatably connected in a partially overlapping state. For connecting the bending pieces, it is possible to use rivet joining or the like. 【0004】 The bending portion configured as described above can be bent in, for example, four directions of up and down and left and right by an operation wire (bending wire) inserted into the bending tube. 【0005】 Conventionally, various techniques have been proposed as endoscopes for improving the operability of such a bending portion. For example, Japanese Patent Application Laid-Open No. 2014-108171 discloses a technique for avoiding interference between a rivet member and a bending wire guide member by regulating the position of the bending wire guide member by the distance from the center of the bending piece to the inner peripheral surface of the connection piece base portion and the distance from the center of the bending piece to the inner peripheral surface of the connection base. 【0006】 Generally, when connecting bending pieces using rivet joining or the like, it is necessary to plastically process the end portion of the rivet at the portion where the bending pieces overlap each other. 【0007】 The sliding resistance of such connecting parts is easily affected by factors such as press load during plastic deformation. Therefore, connecting curved pieces without increasing the sliding resistance of the connecting parts requires the skilled abilities of the operator. 【0008】 The present invention has been made in view of the above circumstances, and aims to provide a bending tube for an endoscope, an endoscope, a method for manufacturing a bending tube for an endoscope, and a bending tube for an insertion device that can reduce the sliding resistance between tubular members regardless of the skills of the manufacturing worker. [Disclosure of the Invention] [Means for solving the problem] 【0009】 A curved tube of an endoscope according to one aspect of the present invention includes a first tubular member and a second tubular member having an overlapping portion that overlaps the end of the first tubular member, the overlapping portion having a pivot shaft formed thereon that is rotatably connected to the first tubular member, wherein the end of the first tubular member has a first hole into which the pivot shaft is inserted, passing through the end in the radial direction of the longitudinal axis, and a protrusion is formed around the opening of the first hole, the pivot shaft has a second hole passing through in the axial direction of the pivot shaft, and the overlapping portion has a recess formed to receive the protrusion. 【0010】 An endoscope according to one aspect of the present invention has a flexible bending portion in the insertion section, the bending portion comprising a first tubular member and a second tubular member having an overlapping portion that overlaps the end of the first tubular member, the overlapping portion having a pivot shaft formed thereon that is rotatably connected to the first tubular member, the end of the first tubular member having a first hole into which the pivot shaft is inserted, passing through the end in the radial direction of the longitudinal axis, an annular protrusion formed around the opening of the first hole, the pivot shaft having a second hole that passes through in the axial direction of the pivot shaft, and the overlapping portion having an annular recess formed to receive the protrusion. 【0011】 A method for manufacturing a curved tube for an endoscope according to one aspect of the present invention includes the steps of: (a) forming a first hole having a predetermined inner diameter in a first plate material; (b) forming a protrusion around the first hole on a first surface of the first plate material; (c) forming a pivot shaft in a second plate material that can be inserted into the first hole, and forming a second hole that penetrates in the axial direction of the pivot shaft; (d) forming a recess around the pivot shaft to receive the protrusion; (e) inserting the pivot shaft into the first hole from the side of the first surface such that the protrusion and the recess face each other; (f) widening the inner diameter of the second hole at the tip of the pivot shaft so that the outer diameter of the tip is larger than the predetermined inner diameter; and (g) bending the first plate material and the second plate material, and joining both ends of the first plate material and the second plate material to form tubular members. 【0012】 A curved tube of an insertion device according to one aspect of the present invention includes a first tubular member and a second tubular member having an overlapping portion that overlaps the end of the first tubular member, the overlapping portion having a pivot shaft formed thereon that is rotatably connected to the first tubular member, wherein the end of the first tubular member has a first hole through the end in the radial direction of the longitudinal axis into which the pivot shaft is inserted, a protrusion is formed around the opening of the first hole, the pivot shaft has a second hole that passes through in the axial direction of the pivot shaft, and the overlapping portion has a recess formed to receive the protrusion. [Brief explanation of the drawing] 【0013】 [Figure 1] A perspective view of the endoscope relating to the first embodiment. [Figure 2] A plan view of a curved pipe relating to the first embodiment. [Figure 3] A perspective view relating to the first embodiment, showing the connected state of the first tubular member and the second tubular member. [Figure 4] The first embodiment is shown in the cross-sectional view IV-IV of Figure 2. [Figure 5] The first embodiment is shown in the VV cross-sectional view of Figure 2. [Figure 6]Regarding the first embodiment, cross-sectional view VI-VI of FIG. 3 [Figure 7] Regarding the first embodiment, cross-sectional view VII-VII of FIG. 2 [Figure 8] Regarding the first embodiment, flowchart showing the manufacturing process of the curved pipe [Figure 9A] Regarding the first embodiment, plan view showing the state after the first hole machining process of the first plate material [Figure 9B] Regarding the first embodiment, cross-sectional view IX-IX of FIG. 9A showing the state after the chamfering process [Figure 9C] Regarding the first embodiment, plan view showing the shape of the convex portion formed around the opening of the first hole [Figure 10A] Regarding the first embodiment, plan view showing the state after the second hole machining process of the first plate material [Figure 10B] Regarding the first embodiment, plan view showing an enlarged view of the range X in FIG. 10A [Figure 11] Regarding the first embodiment, plan view showing the state after the third hole machining process of the first plate material [Figure 12] Regarding the first embodiment, plan view showing the state after the step bending process of the first plate material [Figure 13A] Regarding the first embodiment, plan view showing the state after the step bending process of the first tubular member preparation [Figure 13B] Regarding the first embodiment, cross-sectional view XIII-XIII of FIG. 13A [Figure 14A] Regarding the first embodiment, plan view showing the state after the fourth hole machining process of the second plate material [Figure 14B] Regarding the first embodiment, plan view showing the state after the burring process of the second plate material [Figure 14C] Regarding the first embodiment, cross-sectional view XIV-XIV of FIG. 14B [Figure 15] Regarding the first embodiment, plan view showing the state after the fifth hole machining process of the second plate material [Figure 16]Plan view showing the state after the sixth hole machining process of the second plate material according to the first embodiment [Figure 17] Plan view showing the second tubular member preparation body in the state after the sixth hole machining process according to the first embodiment [Figure 18A] Perspective view showing the state after the first plate material and the second plate material are overlapped and expanded by caulking according to the first embodiment [Figure 18B] Cross-sectional view showing the state after expansion by an expansion punch according to the first embodiment [Figure 19] Plan view showing the state after the connection part cutting process according to the first embodiment [Figure 20] Plan view showing the state after bending process according to the first embodiment [Figure 21] Plan view showing a modification example of the shape of the convex portion formed around the opening of the first hole according to the first modification example of the first embodiment [Figure 22] Plan view showing a modification example of the shape of the convex portion formed around the opening of the first hole according to the second modification example of the first embodiment [Figure 23] Plan view showing a modification example of the shape of the convex portion formed around the opening of the first hole according to the third modification example of the first embodiment [Figure 24] Plan view showing a modification example of the shape of the convex portion formed around the opening of the first hole according to the fourth modification example of the first embodiment [Figure 25] Plan view showing a modification example of the shape of the convex portion formed around the opening of the first hole according to the fifth modification example of the first embodiment [Figure 26] Cross-sectional view taken along line VI-VI of FIG. 3 according to the second embodiment [Figure 27] Cross-sectional view showing the state after the burring process of the second plate material according to the second embodiment [Figure 28] Cross-sectional view taken along line XIV-XIV of FIG. 14B according to the second embodiment [Figure 29] Cross-sectional view showing the state after expansion by an expansion punch according to the second embodiment [Figure 30]The IX-IX cross-sectional view in Figure 9A shows the state after the chamfering process, relating to the second embodiment. [Best Mode for Carrying Out the Invention] 【0014】 A first embodiment will be described with reference to Figures 1 to 25. 【0015】 In the diagrams used in the following explanation, the scale of each component is different in order to make each component recognizable on the diagram. Therefore, the present invention is not limited to the quantity of components, the shape of components, the ratio of the sizes of components, and the relative positional relationship of each component as shown in these diagrams. 【0016】 The endoscope 1 of this embodiment, shown in Figure 1, is, for example, a single-use medical endoscope that is used only once. This endoscope 1 has an insertion section 2, an operating section 3, and a universal cable 8. 【0017】 The insertion section 2 is a long, slender member that is inserted into the area to be observed. The insertion section 2 has, in order from the tip, a rigid tip section 4, a curved section 5, and a flexible tube section 6. 【0018】 The operating section 3 is connected to the base end of the flexible pipe section 6. This operating section 3 is equipped with an operating lever 7 for bending the curved section 5 in two directions, for example, up and down. 【0019】 The universal cable 8 extends, for example, from the side of the operating unit 3. The extended end (not shown) of the universal cable 8 can be connected to various well-known devices (signal processing devices, light source devices, air supply and water supply devices, etc.) via a connector (not shown). 【0020】 Next, we will explain the configuration of the tip side of the insertion part 2, mainly focusing on the configuration of the curved part 5. 【0021】 The rigid tip portion 4 of the insertion portion 2 is made of a rigid material. The rigid tip portion 4 is equipped with, for example, an illumination optical system for illuminating the inside of the subject and an objective optical system of an imaging unit for imaging the inside of the subject. Furthermore, the tip surface of the rigid tip portion 4 has openings for, for example, an air supply channel for supplying fluid into the subject and a treatment instrument insertion channel for leading out treatment instruments such as forceps. 【0022】 The curved section 5 comprises a curved pipe 10 (see Figure 2) and a flexible outer tube (not shown) made of rubber or the like that covers the outer circumference of the curved pipe 10. 【0023】 The curved pipe 10 has a front tubular member 11A connected to the rigid tip portion 4 and a rear tubular member 11B connected to the flexible pipe portion 6. In the following description, these front tubular member 11A and rear tubular member 11B will be collectively referred to as the end tubular members 11 as appropriate. 【0024】 Furthermore, between the tubular members 11 at both ends, the curved pipe 10 has a plurality of first tubular members 12 and a plurality of second tubular members 13 as curved sections. These first tubular members 12 and second tubular members 13 each have a substantially annular shape. The first tubular members 12 and second tubular members 13 are arranged alternately along the longitudinal axis O direction of the insertion section 2. In addition, adjacent first tubular members 12 and second tubular members 13 are rotatably connected. 【0025】 Each of the first tubular members 12 is configured to have a first hinge portion 15 and a first peripheral wall portion 16, as shown in Figure 3. 【0026】 The first hinge portion 15 is provided in pairs at positions symmetrical with respect to the central axis (i.e., longitudinal axis O) of the first tubular member 12. 【0027】 The first hinge portion 15 has a first flat plate portion 20 and a second flat plate portion 21. 【0028】 The first flat plate portion 20 has a substantially elliptical shape in plan view. First tongue portions 25 are formed at both ends of the first flat plate portion 20 in the direction of the longitudinal axis O. The first tongue portions 25 function as first connecting portions for overlapping and connecting the ends of the second tubular member 13. A first hole 26 is formed in the center of the first tongue portion 25. This first hole 26 is a hole that penetrates the first tongue portion 25 in the radial direction of the longitudinal axis O (in the direction perpendicular to the longitudinal axis O). 【0029】 The second flat plate portion 21 is provided at both ends of the first flat plate portion 20. 【0030】 Furthermore, a stepped portion 23 is formed between the first flat plate portion 20 and the second flat plate portion 21. Due to this stepped portion 23, the first flat plate portion 20 is positioned on the outer circumference side of the first tubular member 12 by the thickness of the first tubular member 12 relative to the second flat plate portion 21. 【0031】 The first peripheral wall portion 16 is provided in pairs between the pair of first hinge portions 15, and at positions symmetrical with respect to the longitudinal axis O. A first ridge line 17 is formed between the first hinge portion 15 and the first peripheral wall portion 16. 【0032】 Figure 4 is a cross-sectional view taken along line IV-IV of Figure 2. As shown in Figure 4, a first wire receiver 28 is provided on one of the pair of first peripheral wall portions 16. The first wire receiver 28 is formed by creating two circumferentially extending slits in the first peripheral wall portion 16, and causing the strip-shaped portion between the two slits to protrude radially inward in a C-shape. The first wire receiver 28 is positioned 90° away from the first flat plate portion 20 in the circumferential direction of the first tubular member 12. 【0033】 As will be described later, the first tubular member 12 in this embodiment is formed by processing a flat plate-shaped first tubular member preparation 12a into a tubular shape. For this reason, the first tubular member 12 has a first joint portion 29 formed along the longitudinal axis O direction. 【0034】 Each of the second tubular members 13 is configured to have a second hinge portion 30 and a second peripheral wall portion 31, as shown in Figure 3. The wall thickness of the second tubular member 13 is approximately the same as the wall thickness of the first tubular member 12. 【0035】 The second hinge portion 30 is provided in pairs at positions symmetrical with respect to the central axis (longitudinal axis O) of the second tubular member 13. 【0036】 The second hinge portion 30 is formed by a flat plate portion having a substantially elliptical shape in plan view. Second tongue portions 33 are formed at both ends of the second hinge portion 30 in the direction of the longitudinal axis O. The second tongue portions 33 function as overlapping portions to which the ends of the first tubular member 12 (first tongue portions 25) are overlapped. Furthermore, the second tongue portions 33 function as second connecting portions for connecting the first tongue portions 25. A projection 35 serving as a pivot axis is formed in the center of the second tongue portion 33. This projection 35 protrudes from the second tongue portion 33 in the outer diameter direction of the longitudinal axis O (a direction perpendicular to the longitudinal axis O). Furthermore, the projection 35 has a second hole 34. This second hole 34 is a hole that penetrates the second tongue portion 33 and the projection 35 in the radial direction of the longitudinal axis O. Such protrusions 35 are formed, for example, by burring. 【0037】 The second peripheral wall portion 31 is provided in pairs between the paired second hinge portions 30, and at positions symmetrical with respect to the longitudinal axis O. 【0038】 A second ridge line 32 is formed between the second hinge portion 30 and the second peripheral wall portion 31, which are configured in this way. 【0039】 Figure 5 is a cross-sectional view of VV in Figure 2. As shown in Figures 3 and 5, a second wire receiver 36 is provided on one of the pair of second peripheral wall portions 31. The second wire receiver 36 is formed by the same manufacturing method as the first wire receiver 28. The second wire receiver 36 is positioned 90° away from the second hinge portion 30 in the circumferential direction of the second tubular member 13. 【0040】 As will be described later, the second tubular member 13 is formed by processing the flat plate-shaped second tubular member preparation 13a into a tubular shape. For this reason, the second tubular member 13 has a second joint portion 38 formed along the longitudinal axis O direction. 【0041】 The protruding portion 35 of the second tubular member 13, configured in this way, is inserted into the first hole 26 of the adjacent first tubular member 12. That is, with the second tongue portion 33 superimposed on the first tongue portion 25, the protruding portion 35 is inserted into the first hole 26. The tip of the protruding portion 35 is then expanded (crimped) to connect the first tubular member 12 and the second tubular member 13 so that they can rotate. 【0042】 Figure 6 is a cross-sectional view taken along line VI-VI in Figure 3. As shown in Figure 6, each of the first holes 26 has a uniform diameter portion 26a and an enlarged portion 26b in which the inner diameter increases. Furthermore, on the inner surface of the first tongue portion 25, a protrusion 26c is formed around the opening of the first hole 26. 【0043】 In the first hole 26, the portion with the same diameter 26a is provided in a region closer to the inner surface in the thickness direction of the first tongue portion 25. 【0044】 Furthermore, in the first hole 26, the enlarged portion 26b is provided in a region of the first tongue portion 25 closer to the outer surface in the thickness direction. The base end (inner surface side in the thickness direction of the first tongue portion 25) of the enlarged portion 26b is connected to the same diameter portion 26a. The tip end (outer surface side in the thickness direction of the first tongue portion 25) of the enlarged portion 26b is open to the outer surface of the first tongue portion 25. 【0045】 The enlarged portion 26b has a tapered shape, with its inner diameter increasing from the base end to the tip end. That is, the inner diameter of the enlarged portion 26b increases towards the tip of the projection 35 (rotation axis) inserted into the first hole 26. Specifically, the inner diameter of the base end of the enlarged portion 26b is equal to the inner diameter d1 of the same-diameter portion 26a. Also, the inner diameter d2 of the tip end of the enlarged portion 26b is larger than the inner diameter d1 of the same-diameter portion 26a. As a result, the enlarged portion 26b has, for example, a frustoconical shape. 【0046】 The convex portion 26c is formed by a projection that extends along the portion 26a of the same diameter and faces the enlarged portion 26b. Therefore, the apex of the convex portion 26c abuts against the outer surface of the second tongue portion 33 when the first tubular member 12 and the second tubular member 13 are connected. 【0047】 The enlarged portion 26b and the protruding portion 26c of the first hole 26 are formed, for example, by chamfering the first hole 26 as described later. 【0048】 Furthermore, the inner diameter d1 of the first hole 26, which is connected in this manner, is set to be slightly larger than the outer diameter d3 of the protruding portion 35. 【0049】 When the first tubular member 12 and the second tubular member 13 are connected, a retaining element 39 is formed at the tip of the protruding portion 35 to maintain engagement between the first hole 26 and the protruding portion 35. This retaining element 39 is formed by expanding the tip of the protruding portion 35 to an expansion diameter d4 that is larger than the inner diameter d1 of the first hole 26. Due to this retaining element 39, a portion of the tip side of the protruding portion 35 is formed to conform to the shape of the surface of the enlarged portion 26b. In addition, although it is stated that the tip of the protruding portion 35 is expanded to an expansion diameter d4 that is larger than the inner diameter d1 of the first hole 26 in order to form the retaining element 39, it is sufficient to prevent the first tubular member 12 and the second tubular member 13 from falling out of their connected state, and it is also acceptable for the tip of the protruding portion 35 to be expanded to a size larger than the inner diameter d1. 【0050】 Furthermore, when the first tubular member 12 and the second tubular member 13 are connected, the first wire receiver 28 and the second wire receiver 36 are positioned 180° apart from each other in the circumferential direction of the curved pipe 10. 【0051】 The curved tube 10 configured in this way can be bent in two directions by operating wires (not shown) inserted into the first wire receiver 28 and the second wire receiver 36. 【0052】 In this embodiment, the curved pipe 10 is configured to be curved in two directions, but it may also be configured to be curved in four directions. 【0053】 Furthermore, when the first tubular member 12 and the second tubular member 13 are connected, the first joint 29 and the second joint 38 are positioned such that the angle from the first hinge portion 15 to the first joint 29 around the longitudinal axis O of the curved pipe 10 is approximately the same as the angle from the second hinge portion 30 to the second joint 38 around the longitudinal axis O of the curved pipe 10 (see Figure 3). 【0054】 Figure 7 is a cross-sectional view taken along line VII-VII of Figure 2. As shown in Figures 2 and 7, each of the two end tubular members 11 is basically configured in substantially the same way as the first tubular member 12. However, in the front end tubular member 11A, the first hinge portion 15 is provided with a first tongue portion 25 only on the base end side in the longitudinal axis O direction. Also, a connecting portion 49 for connecting the curved pipe 10 to the tip rigid portion 4 is provided on the tip side in the longitudinal axis O direction of the front end tubular member 11A. On the other hand, in the rear end tubular member 11B, the first hinge portion 15 is provided with a first tongue portion 25 only on the tip side in the longitudinal axis O direction. Also, a connecting portion 49 for connecting the curved pipe 10 to the flexible pipe portion 6 is provided on the base end side in the longitudinal axis O direction of the rear end tubular member 11B. In addition, among the various components of the tubular members 11 at both ends, the components corresponding to the first tubular member 12 are denoted by the same reference numeral and their descriptions are omitted. 【0055】 Next, a method for manufacturing the curved pipe 10 according to this embodiment will be described. Figure 8 is a flowchart of the manufacturing process for the curved pipe 10. In the manufacturing process for the curved pipe 10 shown below, the curved pipe 10 is manufactured by processing the first plate material 51 and the second plate material 61. 【0056】 As shown in Figure 8, in the manufacturing process of the curved pipe 10, the first metal plate material 51 is processed in steps S101 to S105. The processing of the first plate material 51 forms a tubular member preparation 11a that forms the tubular members 11 at both ends, and a first tubular member preparation 12a that forms the first tubular member 12. 【0057】 Steps S101 to S105 are described below. Steps S101 to S105 are performed by press working using a die. 【0058】 In the processing of the first plate material 51, a first hole is drilled into the first plate material 51 in step S101. Figure 9A shows the state of the first plate material 51 after the first hole is drilled. As shown in Figure 9A, in the first hole drilling, for example, first holes 26 are formed in the first plate material 51 corresponding to the tubular members 11 at both ends and the plurality of first tubular members 12. Furthermore, in the first hole drilling, a plurality (for example, 8) of first positioning holes 59 are formed in the first plate material 51. 【0059】 In the subsequent step S102, chamfering is performed on the first hole 26. Figure 9B shows the state after chamfering. As shown in Figure 9B, the chamfering is performed using a chamfering punch 37 and a base 41. The base 41 has a recess 41a for forming a protrusion 26c. As shown in Figure 9B, in the chamfering process, for example, the first plate material 51 is placed on the base 41 in a positioned state. At this time, positioning on the base 41 is performed, for example, using the first positioning hole 59. The first surface of the first plate material 51 is in contact with the base 41. Chamfering of the first hole 26 of the first plate material 51 is performed from the second surface side of the first plate material 51 using the chamfering punch 37. 【0060】 In this embodiment, the first surface of the first plate material 51 is the surface that forms the inner circumferential surfaces of the tubular members 11 at both ends and the first tubular member 12. The second surface of the first plate material 51 is the surface that forms the outer circumferential surfaces of the tubular members 11 at both ends and the first tubular member 12. 【0061】 This chamfering process creates an enlarged portion 26b in the first hole 26. Furthermore, a protrusion 26c is formed around the opening of the first hole 26. 【0062】 The enlarged portion 26b is formed by chamfering with a chamfering punch 37 with a tapered tip, thereby crushing the corner of the first hole 26 at an angle of, for example, 45 degrees. Therefore, the inner diameter d2 of the tip end of the enlarged portion 26b is larger than the inner diameter d1 of the same-diameter portion 26a of the first hole 26 (see Figure 6). 【0063】 The protrusion 26c is formed by a portion of the first plate material 51 that protrudes toward the first surface due to the plastic flow of the first plate material 51 caused by chamfering. Specifically, when chamfering is performed, the portion of the first plate material 51 that protrudes due to plastic flow deforms to conform to the shape of the recess 41a of the base 41. As a result, the protrusion 26c is formed to protrude from the first plate material 51 at approximately the same time that the corner of the first hole 26 is crushed by the chamfering punch 37. In other words, the protrusion 26c is formed at approximately the same time as chamfering (formation of the enlarged portion 26b). The shape of this protrusion 26c is formed, for example, in an annular shape, as shown in Figure 9C. 【0064】 Furthermore, chamfering with the chamfering punch 37 is not limited to chamfering burrs; it may also be used to chamfer sagging surfaces. 【0065】 In the subsequent step S103, a second hole is drilled into the first plate material 51. Figure 10A shows the state of the first plate material 51 after the second hole drilling. As shown in Figure 10A, the second hole drilling creates a first wire receiving preparation portion 28a in the first plate material 51, which forms the first wire receiving portion 28 of the first tubular member 12. 【0066】 Figure 10B is an enlarged view of the range X in Figure 10A. As shown in Figure 10B, the first wire receiving preparation portion 28a is formed by creating multiple pairs of slits 27 in the first plate material 51 by the second hole processing. The first wire receiving preparation portion 28a is formed, for example, by processing the first tubular member 12 radially inward into a C shape during the bending process in step S113, which will be described later. This forms the first wire receiving portion 28. 【0067】 In the subsequent step S104, a third hole is drilled into the first plate material 51. Figure 11 shows the state of the first plate material 51 after the third hole drilling. As shown in Figure 11, the third hole drilling creates a tubular member preparation 11a that forms the tubular members 11 at both ends, and a first tubular member preparation 12a that forms the first tubular member 12. 【0068】 In other words, the third hole processing creates a plurality of punched holes 53 in the first plate material 51 at predetermined intervals. As a result, a plurality of first tubular member preparations 12a arranged in a row are formed in the first plate material 51. Here, the intervals between the plurality of punched holes 53 are set to be appropriate for arranging the second tubular member preparations 13a. Furthermore, the third hole processing creates a pair of punched holes 54 in the first plate material 51. These punched holes 54 are formed at both ends of the arrangement of the plurality of first tubular member preparations 12a. As a result, tubular member preparations 11a at both ends are formed in the first plate material 51. 【0069】 Each of the punched holes 53 and 54 forms the first tongue portion 25 of the tubular member preparations 11a and 12a on the first plate material 51. In each of the first tubular member preparations 12a, both ends of the strip-shaped portion that forms the first peripheral wall portion 16 are connected to the first edge 56 of the first plate material 51 via the first connecting portion 55. The end of the tubular member preparation 11a opposite to the side where the first tongue portion 25 is provided is connected to the first edge 56 via the connecting portion 58. 【0070】 The eight first positioning holes 59 formed in step S101 described above are provided on the first edge 56. Furthermore, the first tubular member preparation 12a may be configured such that only one end is connected to the first edge 56 via the first connecting portion 55, while the other end is not connected to the first edge 56. 【0071】 In the subsequent step S105, the first plate material 51 is subjected to step bending. Figure 12 shows the state after the step bending of the first plate material 51. As shown in Figure 12, the step bending process creates stepped portions 23 in the thickness direction of the first plate material 51 on both end tubular member preparations 11a and the first tubular member preparation 12a. 【0072】 Figure 13A shows the first tubular member preparation 12a after step bending. Figure 13B is a cross-sectional view taken along line XIII-XIII in Figure 13A. As shown in Figures 13A and 13B, the first tubular member preparation 12a after step bending has a first hinge preparation 15a and a first peripheral wall preparation 16a formed thereon. 【0073】 Between the first hinge preparation portion 15a and the first peripheral wall preparation portion 16a, a first ridge-forming portion 17a is provided, which forms the first ridge line 17 after the first tubular member preparation body 12a, which will be described later, is bent into an annular shape (step S113). The stepped portion 23 forms a first flat plate portion 20 and a second flat plate portion 21 on the first hinge preparation portion 15a. The step difference between the first flat plate portion 20 and the second flat plate portion 21 at the stepped portion 23 is equal to the wall thickness of the first tubular member preparation body 12a. 【0074】 Furthermore, the step bending process in step S105 creates a stepped portion 23b between the first edge 56 of the first plate material 51 and each of the first tubular member preparations 12a. By providing this stepped portion 23b, the first edge 56 of the first plate material 51 and the first flat plate portion 20 are arranged on the same plane. 【0075】 Furthermore, in the step bending process of step S105, a first flat plate portion 20 and a second flat plate portion 21 are formed in the hinge portion preparation portion (not shown) of the tubular member preparation body 11a at both ends by the stepped portion 23. 【0076】 Next, in steps S106 to S109, the second metal plate 61 is processed. The processing of the second plate 61 forms a second tubular member preparation 13a, which will form the second tubular member 13. 【0077】 Steps S106 to S109 will be explained below. Note that each step in steps S106 to S109 is performed by press working using a die. 【0078】 In the processing of the second plate material 61, a fourth hole is drilled in the second plate material 61 during step S106. Figure 14A shows the state of the second plate material 61 after the fourth hole drilling has been performed. As shown in Figure 14A, in the fourth hole drilling, for example, multiple burring pilot holes 35a are formed in the second plate material 61. These pilot holes 35a are formed at positions corresponding to the second holes 34 that correspond to the multiple second tubular members 13. 【0079】 Furthermore, in the fourth hole processing, a plurality (for example, 8) second positioning holes 69 are formed in the second plate material 61. Each of these second positioning holes 69 is formed at a position corresponding to each of the first positioning holes 59 formed in the first plate material 51. 【0080】 In the subsequent step S107, the second plate material 61 is subjected to burring. Figures 14B and 14C show the state after burring. As shown in Figures 14B and 14C, the burring process creates a pilot hole 35a, and a projection 35, which is the pivot axis of the second tubular member 13, is formed in the second plate material 61. Furthermore, this burring process creates a second hole 34 in the projection 35 that penetrates in the direction of the projection 35 (the axial direction of the pivot axis). Therefore, for example, the second hole 34 is formed in a cylindrical shape. 【0081】 In the subsequent step S108, a fifth hole is drilled into the second plate material 61. Figure 15 shows the state of the second plate material 61 after the fifth hole drilling. As shown in Figure 15, the fifth hole drilling creates a second wire receiver preparation portion 36a in the second plate material 61, which forms the second wire receiver 36 of the second tubular member 13. That is, the second wire receiver preparation portion 36a is formed by creating multiple pairs of slits 27 in the second plate material 61 through the fifth hole drilling. The second wire receiver 36 is formed, for example, during the bending process in step S113, which will be described later, by the same manufacturing method as the first wire receiver 28. 【0082】 In the subsequent step S109, a sixth hole is drilled into the second plate material 61. Figure 16 shows the state of the second plate material 61 after the sixth hole has been drilled. As shown in Figure 16, the second tubular member preparation 13a is formed in the second plate material 61 by the sixth hole drilling. 【0083】 In other words, the sixth hole-making process creates multiple punched holes 65 in the second plate material 61 at predetermined intervals. As a result, multiple second tubular member preparations 13a are formed in the second plate material 61 in a row. Here, the spacing between the multiple punched holes 65 is set to an appropriate spacing for arranging the first tubular member preparations 12a. 【0084】 Each punched hole 65 forms a second tongue portion 33 of the second tubular member preparation 13a on the second plate material 61. In addition, both ends of the strip-shaped portion that forms the second peripheral wall portion 31 on each second tubular member preparation 13a are connected to the second edge 62 of the second plate material 61 via a second connecting portion 68. 【0085】 Furthermore, the second tubular member preparation 13a may be configured such that only one end is connected to the second edge 62 by the second connecting portion 68, and the other end is not connected to the second edge 62. 【0086】 Figure 17 shows the second tubular member preparation 13a after the sixth hole has been drilled. As shown in Figure 17, the second tubular member preparation 13a has a second hinge preparation 30a and a second peripheral wall preparation 31a. Between the second hinge preparation 30a and the second peripheral wall preparation 31a, there is a second ridge forming section 32a which will form the second ridge 32 after the first tubular member preparation 12a is bent into an annular shape (step S113), as will be described later. 【0087】 Next, in step S110, the first plate material 51, which has been processed in steps S101 to S105, and the second plate material 61, which has been processed in steps S106 to S109, are superimposed. 【0088】 In the overlapping step S110, the second plate material 61 is positioned with the protruding portion 35 of the second tongue portion 33 facing upward. The first plate material 51 is then overlapped on top of the second plate material 61 with the first flat portion 20 positioned above the second flat portion 21. 【0089】 In this process, the first plate material 51 and the second plate material 61 are superimposed using a positioning mechanism within the mold. Specifically, the first plate material 51 and the second plate material 61 are superimposed in a state where their respective first positioning holes 59 and second positioning holes 69 are aligned. 【0090】 In this way, by overlapping the first plate material 51 and the second plate material 61 at positions where each first positioning hole 59 and each second positioning hole 69 coincide, the end-ended tubular member preparation 11a, the first tubular member preparation 12a, and the second tubular member preparation 13a are positioned appropriately. 【0091】 At this time, each protrusion 35 is inserted through each of the first holes 26. This causes each of the first holes 26 and each of the protrusions 35 to engage with each other. This engagement connects the first tubular member preparation 12a and the second tubular member preparation 13a. Similarly, the end-ended tubular member preparations 11a and the second tubular member preparation 13a are connected. 【0092】 In the subsequent step S111, a crimping process is performed on the second hole 34 provided in the protruding portion 35. Figures 18A and 18B show the state after the second hole 34 at the tip of the protruding portion 35 has been expanded by crimping. As shown in Figure 18B, the crimping of the second hole 34 is performed using an expansion punch 40. The expansion by crimping forms a retaining element 39 at the tip of the protruding portion 35. Specifically, with the first tubular member preparation 12a and the second tubular member preparation 13a connected, the tip of the expansion punch 40 is driven into the second hole 34, thereby expanding the tip of the protruding portion 35. 【0093】 Then, a retaining element 39 is formed at the tip of the expanded projection 35. The expanded diameter d4 of the retaining element 39 formed in this way is larger than the inner diameter d1 of the first hole 26. 【0094】 Furthermore, the tip of the expanded projection 35 (more specifically, a part of the tip side of the projection 35) is shaped to conform to the surface of the enlarged portion 26b. 【0095】 In the subsequent step S112, the first and second connecting portions 55 and 68 are cut. Figure 19 shows the state after the connecting portion cutting process. As shown in Figure 19, in the connecting portion cutting process, the first connecting portion 55 of the first plate material 51 is cut, thereby separating the first tubular member preparation 12a from the first edge 56 of the first plate material 51. Also, the second connecting portion 68 of the second plate material 61 is cut, thereby separating the second tubular member preparation 13a from the second edge 62 of the second plate material 61. 【0096】 The tubular member preparation 11a at both ends remains connected to the first edge 56 of the first plate material 51 by the connecting portions 58 at both ends. The cutting process for the connecting portions is performed by press working with a die. 【0097】 Then, in step S113, the first sheet metal 51 and the second sheet metal 61 are bent. More specifically, the first sheet metal 51 is bent into the tubular member preparations 11a at both ends and the first tubular member preparation 12a. The second sheet metal 61 is bent into the second tubular member preparation 13a. The bending is performed, for example, by press working with a die. 【0098】 For example, in the bending process of the tubular member preparation 11a at both ends and the first peripheral wall preparation 16a of the first tubular member preparation 12a, U-shaped bending and O-shaped bending are performed sequentially so that the second surface side of the first plate material 51 becomes the outer peripheral surface of the first tubular member 12. 【0099】 In other words, the bending process is carried out so that the protrusion 26c formed around the opening of the first hole 26 faces radially inward of the first tubular member 12. Similarly, the second peripheral wall preparation portion 31a of the second tubular member preparation 13a is also bent in the same bending direction as the first peripheral wall preparation portion 16a. 【0100】 Figure 20 shows the state after bending. As shown in Figure 20, by bending, the first tubular member 12 is formed by the first tubular member preparation 12a, the second tubular member 13 is formed by the second tubular member preparation 13a, and the tubular members 11 at both ends are formed by the tubular member preparations 11a at both ends. 【0101】 In the above description, an example was given in which the protrusion 26c is bent so that it faces radially inward of the first tubular member 12. However, the bending process may also be performed so that the protrusion 26c faces radially outward of the first tubular member 12. 【0102】 Furthermore, after the bending process (step S113), a first abutment portion 29a is formed on the first tubular member preparation 12a, where both end faces abut against each other. Similarly, a first abutment portion 29a is formed on the end tubular member preparation 11a, where both end faces abut against each other. By joining part or all of the first abutment portion 29a by laser welding or the like, a first joint portion 29 is formed along the axial direction of the first tubular member 12. 【0103】 Similarly, the second tubular member preparation 13a has a second abutment portion 38a formed where both end faces abut against each other. By joining all or part of the second abutment portion 38a, a second joint portion 38 is formed along the axial direction of the second tubular member 13. 【0104】 These joining processes complete the first tubular member 12 and the second tubular member 13. 【0105】 After this bending process is completed, the connecting portions 58 at both ends are cut, and the tubular member preparations 11a at both ends are separated from the first edge 56, thereby completing the curved pipe 10. 【0106】 According to this embodiment, the curved tube 10 of the endoscope 1 includes a first tubular member 12 having a first tongue portion 25, and a second tubular member 13 having a second tongue portion 33 that overlaps the first tongue portion 25, and having a projection 35 that is rotatably connected to the first tongue portion 25. The first tongue portion 25 of the first tubular member 12 has a first hole 26 that penetrates the first tongue portion 25 in the radial direction of the longitudinal axis O, into which the projection 35 is inserted. The first tongue portion 25 also has a convex portion 26c formed around the first hole 26. The projection 35 also has a second hole 34 that penetrates the projection 35 in the axial direction (projection direction) of the projection 35. Furthermore, the second tongue portion 33 is provided on the second tubular member 13 such that the convex portion 26c abuts against the surface. These configurations allow the bending tube 10 of the endoscope 1 to reduce sliding resistance between tubular members, regardless of the skill of the manufacturing worker. 【0107】 In other words, the curved pipe 10, which is formed by connecting the first tubular member 12 and the second tubular member 13, has a protrusion 26c that abuts against and slides against the surface of the overlapping portion of the second tongue portion 33 when it is curved. Due to the action of this protrusion 26c, the contact area between the overlapping portion (first tongue portion 25 and second tongue portion 33) that connects the tubular members can be reduced when the protrusion 26c abuts against the overlapping portion and slides against it. Therefore, the sliding resistance between the tubular members can be reduced compared to a curved pipe that does not have a protrusion 26c. 【0108】 When connecting the first tubular member 12 and the second tubular member 13, the second tongue portion 33 is placed on top of the first tongue portion 25, and the projection portion 35 is inserted into the first hole 26. At this time, the convex portion 26c provided on the first tongue portion 25 comes into contact with the surface of the second tongue portion 33. Then, the second hole 34 provided on the projection portion 35 is expanded by press working or the like. Even if a large press load is applied during such press working, the first tongue portion 25 and the second tongue portion 33 are in contact via the convex portion 26c, so an excessive increase in sliding resistance is suppressed. Therefore, the sliding resistance between the tubular members can be reduced regardless of the skill of the manufacturing worker. 【0109】 Furthermore, the reduction in sliding resistance between the first tongue portion 25 and the second tongue portion 33 due to the protrusion 26c allows for smoother operation of the curved tube 10 itself. Consequently, improved responsiveness in the operation of the insertion portion 2 of the endoscope 1 can also be achieved. 【0110】 Furthermore, the protrusion 26c provided on the first tongue portion 25 is formed by press processing such as chamfering using a chamfering punch 37 and a recess 41a provided on the base 41. When chamfering is performed by such press processing, the protrusion 26c is formed by deforming a part of the first plate material 51 that has protruded due to plastic flow to conform to the shape of the recess 41a of the base 41. Therefore, by changing the shape of the recess 41a, it is also possible to form protrusions of various shapes around the first hole 26. 【0111】 Figures 21 to 25 show modified shapes of the protrusion 26c. Each figure shows the shape of the protrusion after the shape of the recess 41a in this embodiment has been changed and then press-formed. 【0112】 Figure 21 is a plan view showing a modified shape of the protrusion formed around the opening of the first hole. As shown in Figure 21, the first tongue portion 25 has two identical arc-shaped protrusions 26d. These protrusions 26d are positioned opposite each other around the first hole 26. By forming discontinuous protrusions 26d in this way, the contact area between the first tongue portion 25 and the second tongue portion 33 can be reduced compared to the annular protrusion 26c described above. Therefore, the protrusions 26d can further reduce the sliding resistance between the tubular members. 【0113】 Figure 22 is a plan view showing a modified shape of the protrusion formed around the opening of the first hole. As shown in Figure 22, the first tongue portion 25 has three identical arc-shaped protrusions 26e. These protrusions 26e are arranged in an annular pattern at equal intervals around the first hole 26. By forming discontinuous protrusions 26e in this way, the contact area between the first tongue portion 25 and the second tongue portion 33 can be further reduced compared to the protrusions 26d described above. Therefore, the protrusions 26e can further reduce the sliding resistance between the tubular members. 【0114】 Figure 23 is a plan view showing a modified shape of the protrusions formed around the opening of the first hole. As shown in Figure 23, the first tongue portion 25 has four identical arc-shaped protrusions 26f. These protrusions 26f are arranged in an annular pattern at equal intervals around the first hole 26. By forming discontinuous protrusions 26f in this way, the contact area between the first tongue portion 25 and the second tongue portion 33 can be reduced compared to the protrusions 26e described above. Therefore, the protrusions 26f can further reduce the sliding resistance between the tubular members. 【0115】 Figure 24 is a plan view showing a modified shape of the protrusions formed around the opening of the first hole. As shown in Figure 24, the first tongue portion 25 has four identical elliptical protrusions 26g. These protrusions 26g are arranged in an annular pattern at equal intervals around the first hole 26. By forming discontinuous protrusions 26g in this way, the contact area between the first tongue portion 25 and the second tongue portion 33 can be reduced compared to the protrusions 26e described above. Therefore, the protrusions 26g can further reduce the sliding resistance between the tubular members. 【0116】 Figure 25 is a plan view showing a modified shape of the protrusion formed around the opening of the first hole. As shown in Figure 25, the first tongue portion 25 has three identical elliptical protrusions 26h. These protrusions 26h are arranged in an annular pattern at equal intervals around the first hole 26. By forming discontinuous protrusions 26h in this way, the contact area between the first tongue portion 25 and the second tongue portion 33 can be reduced compared to the protrusion 26e described above. Therefore, the protrusions 26h can further reduce the sliding resistance between the tubular members. 【0117】 Furthermore, the protrusions 26c can be formed in various shapes by changing the thickness of the first plate material 51, the tip shape of the chamfering punch 37, and press working conditions such as the press load. In addition, protrusions of various shapes can be formed by combining the shape of the recess 41a with the press working conditions. 【0118】 The second embodiment will be described below with reference to Figures 26 to 30. In the following, only the differences from the first embodiment will be described, and components similar to those in the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate. 【0119】 As shown in Figure 26, the second tongue portion 33 of this embodiment has, for example, a recess 35b that receives an annular protrusion 26c. 【0120】 The recess 35b is formed at a position opposite the protrusion 26c. As shown in Figure 27, this recess 35b is formed approximately simultaneously with the second hole 34 and the protrusion 35 during the burring process in step S107. 【0121】 Specifically, the burring process in this embodiment is performed using a punch 60 and a base 63. The base 63 has a protrusion 63a for forming a recess 35b. 【0122】 The dimensions of the protrusion 63a are set based on the dimensions of the protrusion 26c. For example, the radial width of the protrusion 63a is set to be slightly larger than the radial width of the protrusion 26c. Also, the protruding length of the protrusion 63a is set to be slightly smaller than the protruding length of the protrusion 26c. 【0123】 Then, in the burring process, for example, the second plate material 61 is placed on the base 63 in a positioned state. At this time, positioning on the base 63 is performed, for example, using the second positioning hole 69 (see Figure 14A). The protruding surface of the second plate material 61 used for burring is in contact with the base 63. Then, as shown in Figure 27, the second plate material 61 is placed on the base 63, and burring is performed on the pilot hole 35a of the second plate material 61 using the punch 60. 【0124】 Through this burring process, the second hole 34 and the protrusion 35 are formed in the second plate material 61, and at approximately the same time, a recess 35b is formed following the shape of the convex portion 63a (see Figures 27 and 28). 【0125】 The protrusion 26c is accommodated in the recess 35b formed in this manner. The recess 35b is preferably annular, but it is sufficient that it can accommodate the protrusion 26c, and may be formed, for example, as a partial annular shape to match the shape of the protrusion 26c. 【0126】 Specifically, the protruding portion 35 is inserted into the first hole 26 by overlapping the second tongue portion 33 with the first tongue portion 25. At this time, the convex portion 26c provided on the first tongue portion 25 is housed in the recess 35b provided on the second tongue portion 33 with the convex portion 26c in contact with the recess 35b. 【0127】 Then, during the crimping process in step S111, the tip of the protruding portion 35 is expanded, thereby rotatably connecting the first tubular member 12 and the second tubular member 13 (see Figure 29). 【0128】 The other configurations are the same as those of the first embodiment described above. 【0129】 According to this embodiment, the curved tube 10 of the endoscope 1 has a recess 35b that receives the protrusion 26c on the second tongue portion 33 of the second tubular member 13. With this configuration, in addition to the effects obtained in the first embodiment described above, the following effects can be achieved. 【0130】 In other words, in this embodiment, by housing the protrusion 26c in the recess 35b of the curved pipe 10, the connection strength between the tubular members is improved, and the durability of the curved pipe 10 can be enhanced. 【0131】 More specifically, in this embodiment, even when a protrusion 26c is formed on the first tongue portion 25 of the curved tube 10, the increase in the distance from the surface of the second tongue portion 33 facing the first tongue portion 25 to the second surface of the first tongue portion 25 can be suppressed. As a result, even when a protrusion 26c is formed on the first tongue portion 25, the expansion diameter d4 can be increased without increasing the amount of protrusion of the protrusion 35. Therefore, in this embodiment, the curved tube 10 can improve the durability of the bending operation while maintaining the sliding properties between the tubular members. 【0132】 Furthermore, the depth and width of the recess 35b are set according to the height and width required for the protrusion 26c. In other words, the dimensions of the protrusion 63a during burring are set based on the dimensions required for the protrusion 26c. As a result, even if the protrusion amount (volume) of the protrusion 26c is increased, the recess 35b can accurately accommodate the protrusion 26c, minimizing the gap in the overlapping portion. 【0133】 Furthermore, by increasing the protrusion amount (volume) of the convex portion 26c, the excess first plate material 51 generated by the chamfering process in step S102 can be absorbed by the convex portion 26c (see Figure 30). Therefore, surface distortion that occurs on the first surface of the first tongue portion 25 when chamfering can be suppressed. 【0134】 In other words, by setting the volume of the protrusion 26c according to the volume of the first plate material 51 extruded by the chamfering process, it is possible to suppress the excess first plate material 51 from flowing to parts other than the protrusion 26c. Therefore, in this embodiment, even when the enlarged portion 26b of the curved pipe 10 is made larger for purposes such as improving the connection strength by crimping, surface distortion of the first tongue portion 25 can be suppressed. 【0135】 Furthermore, it is preferable that the recess 35b is formed approximately simultaneously with the second hole 34 and the protrusion 35 formed during the burring process. When the recess 35b is formed following the shape of the convex portion 63a, for example, a portion of the second plate material 61 pressed into the convex portion 63a flows into the protrusion 35. This portion of the second plate material 61 that flows into the protrusion 35 is then used to shape the protrusion 35. 【0136】 As a result, even if the diameter of the pilot hole 35a before the burring process is increased, the length of the protruding portion 35 can be maintained. Therefore, the curved pipe 10 in this embodiment can improve the formability when forming the protruding portion 35. 【0137】 The inventions described in each of the above embodiments are not limited to those forms, and various modifications can be made in practice without departing from the gist of the invention. For example, the curved tube 10 shown in each embodiment can also be applied to insertion devices such as catheters, stents, and treatment instruments. 【0138】 Furthermore, the embodiments described above include inventions at various stages, and various inventions can be extracted by appropriate combinations of the multiple constituent elements disclosed. 【0139】 Furthermore, if the problems described can be solved and the effects described can be obtained even if some of the constituent elements shown in the above-described embodiments are deleted, then the configuration with these deleted constituent elements can be extracted as an invention. 【0140】 This application is filed on the basis of priority claim to U.S. Patent No. 63 / 404559, provisionally filed on 8 September 2022, and the foregoing is incorporated herein by reference in the specification, claims, and drawings.

Claims

[Claim 1] A first tubular member and The present invention includes a second tubular member having an overlapping portion that overlaps the end of the first tubular member, and having a pivot shaft formed in the overlapping portion that is rotatably connected to the first tubular member, The end of the first tubular member has a first hole into which the pivot shaft is inserted, which penetrates the end in the radial direction of the longitudinal axis. A protrusion is formed around the opening of the first hole. The pivot shaft has a second hole that penetrates in the axial direction of the pivot shaft, The bending tube of an endoscope is characterized in that a recess is formed in the overlapping portion to receive the convex portion. [Claim 2] The curved tube of the endoscope according to claim 1, characterized in that the outer diameter of the tip of the pivot shaft is wider than the inner diameter of the first hole. [Claim 3] The first hole has an enlarged portion that expands in diameter toward the tip of the pivot shaft, The curved tube of the endoscope according to claim 1, characterized in that the tip of the pivot shaft is shaped to conform to the enlarged portion. [Claim 4] The curved tube of the endoscope according to claim 3, characterized in that the magnified portion is frustoconical in shape. [Claim 5] The overlapping portion is positioned radially inward of the first tubular member relative to the end portion. The protrusion is provided on the radially inward surface of the end portion, characterized in that 1 The curved tube of the endoscope described above. [Claim 6] The overlapping portion is positioned radially outward of the first tubular member relative to the end portion. The protrusion is provided on the radially outer surface of the end portion, characterized in that 1 The curved tube of the endoscope described above. [Claim 7] The curved tube of the endoscope according to claim 1, characterized in that the recess is formed in an annular shape. [Claim 8] The curved tube of the endoscope according to claim 7, characterized in that the convex portion is formed in an annular shape. [Claim 9] The curved tube of the endoscope according to claim 1, characterized in that the convex portion and the concave portion are arranged to be in contact with each other. [Claim 10] The insertion part has a flexible curved section, The curved portion comprises a first tubular member and Having an overlapping portion that overlaps the end of the first tubular member, The overlapping portion comprises a second tubular member on which a pivot shaft is formed that is rotatably connected to the first tubular member, The end of the first tubular member has a first hole into which the pivot shaft is inserted, which penetrates the end in the radial direction of the longitudinal axis. An annular protrusion is formed around the opening of the first hole. The pivot shaft has a second hole that penetrates in the axial direction of the pivot shaft, The endoscope is characterized in that an annular recess is formed in the overlapping portion to receive the protrusion. [Claim 11] The endoscope according to claim 10, characterized in that the outer diameter of the tip of the pivot shaft is wider than the inner diameter of the first hole. [Claim 12] The first hole has an enlarged portion that expands in diameter toward the tip of the pivot shaft, The endoscope according to claim 10, characterized in that the tip of the pivot shaft is shaped to conform to the enlarged portion. [Claim 13] The endoscope according to claim 12, characterized in that the magnified portion is frustoconical in shape. [Claim 14] The overlapping portion is positioned radially inward of the first tubular member relative to the end portion. The endoscope according to claim 10, characterized in that the protrusion is provided on the radially inward surface of the end portion. [Claim 15] The overlapping portion is positioned radially outward of the first tubular member relative to the end portion. The endoscope according to claim 10, characterized in that the protrusion is provided on the radially outer surface of the end portion. [Claim 16] The endoscope according to claim 10, characterized in that the convex portion and the concave portion are arranged to be in contact with each other. [Claim 17] (a) A step of forming a first hole with a predetermined inner diameter in the first plate material, (b) A step of forming a protrusion around the first hole on the first surface of the first plate material; (c) A step of forming a pivot shaft in the second plate material that can be inserted into the first hole, and a second hole that penetrates in the axial direction of the pivot shaft; (d) A step of forming a recess around the pivot axis to receive the protrusion, (e) Inserting the pivot shaft into the first hole from the side of the first surface such that the convex portion and the concave portion face each other, (f) A step of expanding the inner diameter of the second hole at the tip of the pivot shaft so that the outer diameter of the tip is larger than the predetermined inner diameter, (g) A method for manufacturing a curved tube for an endoscope, comprising the steps of (g) bending the first plate material and the second plate material, and joining both ends of the first plate material and the second plate material to form a tubular member from each plate material. [Claim 18] After performing steps (a) through (d), step (e) is performed. The method for manufacturing a curved tube of an endoscope according to 17, characterized in that step (f) is performed after step (e). [Claim 19] The method for manufacturing a curved tube for an endoscope according to 17, characterized in that in step (g) above, the convex portion is bent so that it faces radially inward of the tubular member. [Claim 20] The method for manufacturing a curved tube for an endoscope according to 17, characterized in that in step (g) above, the convex portion is bent so that it faces radially outward of the tubular member. [Claim 21] The area around the opening of the first hole is chamfered by press working. The method for manufacturing a curved tube of an endoscope according to claim 17, characterized in that the protrusion is formed simultaneously with the chamfering in step (b). [Claim 22] The method for manufacturing a curved tube of an endoscope according to 17, characterized in that in step (c), the second hole is formed in a cylindrical shape by burring. [Claim 23] The method for manufacturing a curved tube of an endoscope according to 22, characterized in that step (c) and step (d) are performed simultaneously by the burring process. [Claim 24] A first tubular member and The present invention includes a second tubular member having an overlapping portion that overlaps the end of the first tubular member, and having a pivot shaft formed in the overlapping portion that is rotatably connected to the first tubular member, The end of the first tubular member has a first hole into which the pivot shaft is inserted, which penetrates the end in the radial direction of the longitudinal axis. A protrusion is formed around the opening of the first hole. The pivot shaft has a second hole that penetrates in the axial direction of the pivot shaft, A curved tube for an insertion device, characterized in that a recess is formed in the overlapping portion to receive the protrusion.

Images