Curved tube and method for manufacturing curved tube

Abstract

To realize a curved tube which can be freely curved in an arbitrary direction with a low load, and to realize a manufacturing method of the curved tube which can remarkably reduce a manufacturing cost.SOLUTION: The bending tube 1 is a bending tube in which a flexible metal plate 50 is formed in a cylindrical shape and which can be freely bent. The curved tube 1 includes the plurality of ring portions 10 arranged apart from each other in the length direction, and the bendable connecting beam portions 30 to 33 that protrude from the opposing end portions of the adjacent ring portions and connect the adjacent ring portions 10. The connecting beam portions 30 to 33 are disposed at at least two positions facing each other in the outer circumferential direction of the ring portion 10. The curved tube 1 is formed into a tubular shape by punching the connection beam portion 30,31,32,33 in the metal plate 50 to form the developed formed plate 51, bending the developed formed plate 51 at the bending line 52, and joining the developed formed plate 51 at the joint portion 53.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bent pipe and a method for manufacturing the bent pipe. [Background technology]

[0002] There is a bending tube in which multiple ring members are connected in the longitudinal direction and can be freely bent between adjacent ring members. Such a bending tube is used, for example, in an endoscope. An endoscope is composed of an insertion section inserted into the body, an operating section, a universal cord, and the like. Here, the insertion section is the part at least partially inserted into the living body and is composed of a tip unit which is an imaging optical system, a flexible tube, and a bending tube connecting the tip unit and the flexible tube. The bending tube can be bent in any direction by operating the operating section, making it possible to point the tip unit in a target direction.

[0003] The bending tube is configured by connecting multiple ring members in the longitudinal direction. A first node ring (ring member) has a through-hole penetrating in the thickness direction. A second node ring (ring member) adjacent to the first node ring has a convex portion that can be inserted into the through-hole. The bending tube is connected to the first ring member by inserting the convex portion of the second ring member into the through-hole of the first ring member and expanding the edge portion of the convex portion. The connecting portion formed by the through-hole and the convex portion forms a hinge structure, and the first ring member and the second ring member rotate relative to each other with the convex portion as the rotation axis. This makes it possible to freely bend the bending tube (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-87929 Summary of the Invention [Problem to be solved by the invention]

[0005] In the bending tube described in Patent Document 1, the first ring member and the second ring member are connected by a hinge portion consisting of a convex portion and a through-hole into which the convex portion is inserted. The bending tube is formed into a cylindrical shape by forming a through-hole for the first ring member in the first substrate and forming a second ring-shaped convex portion in the second substrate, and then connecting the first substrate and the second substrate with the hinge portion. This configuration has the problem of increasing the number of component parts and the number of assembly steps, resulting in high manufacturing costs.

[0006] In addition, the hinge portions are provided at two locations that face each other when viewed in cross section of the bending tube. Therefore, the first ring member and the second ring member can be easily bent in the direction sandwiched between the two hinge portions. However, bending in the direction of the hinge portions places a large load, and there is a problem in that it is difficult to bend in any direction with a low load.

[0007] Therefore, the present invention has been made to solve these problems, and aims to realize a bending tube that can be bent freely in any direction with low load, and to realize a manufacturing method for a bending tube that can significantly reduce manufacturing costs. [Means for solving the problem]

[0008] [1] The bending tube of the present invention is a bending tube in which a flexible metal plate is formed into a cylindrical shape and can be bent freely, and is characterized in that it has a plurality of ring portions arranged spaced apart from each other in the longitudinal direction, and bendable connecting beam portions connecting adjacent ring portions, and the connecting beam portions are arranged in at least two locations facing each other in the circumferential direction of the ring portions.

[0009] [2] In the bending tube of the present invention, it is preferable that there is a gap between the ends of adjacent ring portions, which can restrict the bending deflection when the bending tube is bent to within the range of the maximum allowable deflection.

[0010] [3] In the bending tube of the present invention, a protrusion is provided that protrudes from the end of the ring portion toward the adjacent ring portion, and the protrusion is formed immediately adjacent to the connecting beam portion in the width direction, and it is preferable that there is a gap between the protrusions of the adjacent ring portions that is capable of regulating the maximum allowable deflection when the bending tube is bent.

[0011] [4] In the bending tube of the present invention, it is preferable that the ring portion has a circular or n-sided polygonal (n is an even number) cross section.

[0012] [5] In the curved tube of the present invention, it is preferable that the connecting beam portions are arranged at equal angular intervals around the central axis of the ring portion, and that the connecting beam portions between adjacent ring portions in the subsequent stage are arranged with their positions shifted in the circumferential direction relative to the connecting beam portions between adjacent ring portions in the previous stage.

[0013] [6] In the bending pipe of the present invention, it is preferable that the connecting beam portion is formed by a straight line, a curved line, or a combination of a straight line and a curved line.

[0014] [7] The method for manufacturing a curved tube described in any one of [1] to [6] above is characterized by including a punching step of punching out an expanded shaped plate including the connecting beam portion and the ring portion from the flexible rectangular metal plate, a forming step of forming the punched expanded shaped plate into a cylindrical shape, and a fixing step of fixing two sides that abut when the expanded shaped plate is formed into a cylindrical shape. [Effects of the Invention]

[0015] The bending tube of the present invention has a plurality of cylindrical ring portions arranged at a distance in the longitudinal direction, and adjacent ring portions are connected together by connecting beam portions protruding from the ring portions. The connecting beam portions are provided in at least two locations (180-degree intervals) facing each other in the circumferential direction of the ring portions. With this configuration, when an attempt is made to bend the bending tube, the connecting beam portions can be easily bent, and further, because the connecting beam portions are arranged in a balanced manner between adjacent ring portions, the bending tube can be bent freely in any direction with low load.

[0016] Furthermore, the bending tube described in the above-mentioned prior art connects independently formed ring members with two hinge portions (hinge mechanisms) facing each other in the radial direction. In contrast, the bending tube of the present invention integrally configures multiple ring portions and connecting beam portions, so there is only one component and no process for connecting ring members is required, making it possible to significantly reduce manufacturing costs compared to the prior art. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram showing the configuration of a bending tube 1 according to a first example. [Figure 2] 3 is an enlarged plan view showing the configuration of a connection beam portion 30 according to the first example. FIG. [Figure 3] 3A to 3C are diagrams illustrating a manufacturing method of the bending tube 1 according to the first example. [Figure 4] FIG. 10 is a plan view showing the development forming plate 61 of the bending tube 1 according to the second example. [Figure 5] FIG. 10 is an enlarged plan view showing a part of the development shaping plate 61 according to the second example. [Figure 6] 10 is an enlarged view showing a part of the bending tube 1 according to the first modification. FIG. [Figure 7] 10 is an enlarged plan view showing a part of the development shaping plate 61 according to the second modification. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] The bending tube 1 and the manufacturing method of the bending tube 1 of the present invention will be described below with reference to Figures 1 to 7. Note that the embodiments described below do not limit the invention according to the claims. Furthermore, not all of the elements and combinations thereof described in the embodiments are necessarily essential to the solution of the present invention.

[0019] (Configuration of bending tube 1, first example) FIG. 1 illustrates the configuration of a bending tube 1 according to a first example. FIG. 1(a) is a perspective view showing the overall configuration of the bending tube 1, and FIG. 1(b) shows the cross-sectional shape of the bending tube 1 when it is cut into a cross section. As shown in FIG. 1(a), the bending tube 1 is formed from a flexible metal plate 50 (see FIG. 3) into a cylindrical shape and has a structure that allows it to be freely bent in any direction. The bending tube 1 has multiple ring portions 10. From the left side of the figure, the ring portion 10 is composed of a distal ring portion 11, intermediate ring portions 12, 13, ... 22, and a proximal ring portion 23. The ring portions may be referred to collectively or commonly when they can be described as ring portions 10. In the following description, the ring portion 10 located on the distal ring portion 11 side may be referred to as the upper side, and the ring portion 10 on the right side of the upper side may be referred to as the lower side. The proximal ring portion 23 serves as a fulcrum when bending the bending tube 1. In addition, the distal ring portion 11 is a portion that swings by bending it around the proximal ring portion 23 as a fulcrum, and is a portion that swings by attaching a lens, a working tool, etc., or by inserting a working tool into the bending tube 1.

[0020] Among the multiple ring portions 10, adjacent ring portions 10 are connected by bendable connecting beam portions 30, 31, 32, and 33. The connecting beam portions 30 to 33 and the ring portions 10 are integrally formed, and the bending tube 1 shown in FIGS. 1(a) and 1(b) is formed into a cylindrical shape with a regular octagonal cross section. Therefore, the bending tube 1 is composed of eight surfaces. The surfaces are designated as surfaces 41, 42, 43, 44, 45, 46, 47, and 48. The surfaces 41 to 48 extend along each ring portion 10 in the longitudinal direction of the metal plate 50 (see FIG. 3). The adjacent distal ring portion 11 and intermediate ring portion 12 are connected by connecting beam portions 30 and 31 provided on surface 42 and surface 46 opposite surface 42. That is, the connecting beam portions 30 and 31 are arranged at 180-degree intervals around the central axis P (i.e., plane-symmetrically). Adjacent intermediate ring portions 12 and 13 are connected by connecting beam portions 32 and 33 provided on surface 44 and surface 48 opposite surface 44. That is, connecting beam portions 32 and 33 are arranged at 180-degree intervals around the central axis (i.e., plane-symmetric), and are each arranged at equal angular intervals of 90 degrees with respect to connecting beam portions 30 and 31 about central axis P.

[0021] Furthermore, adjacent intermediate ring portions 13 and 14 are connected by connecting beam portions 30 and 31 provided on surfaces 42 and 46. Adjacent intermediate ring portions 14 and 15 are connected by connecting beam portions 32 and 33 provided on surfaces 44 and 48. Adjacent intermediate ring portions 15 and 16, adjacent intermediate ring portions 16 and 17, adjacent intermediate ring portions 17 and 18, adjacent intermediate ring portions 18 and 19, adjacent intermediate ring portions 19 and 20, adjacent intermediate ring portions 20 and 21, adjacent intermediate ring portions 21 and 22, and adjacent intermediate ring portion 22 and base end ring portion 23 are connected by connecting beam portions 32 and 33 and connecting beam portions 30 and 31, respectively. 1(a), adjacent ring portions 10 alternately have front-stage connecting beam portions 30, 31 and rear-stage connecting beam portions 32, 33 that are shifted 90 degrees in the circumferential direction relative to the connecting beam portions 30, 31. The configuration of the connecting beam portions 30 to 33 will be described with reference to FIG.

[0022] FIG. 2 is an enlarged plan view showing the configuration of a connection beam portion 30 according to the first example. Since the connection beam portions 30 to 33 have the same configuration but different arrangements, the following description will focus on the connection beam portion 30 connecting the adjacent intermediate ring portions 13 and 14. The intermediate ring portion 13 and the intermediate ring portion 14 are connected by a connection beam portion 30 protruding from each of the opposing ends 13a and 14a. The intermediate ring portion 13 has protrusions 13b protruding toward the adjacent intermediate ring portion 14 on both sides of the width of the connection beam portion 30. The intermediate ring portion 14 has protrusions 14b protruding toward the adjacent intermediate ring portion 13 on both sides of the width of the connection beam portion 30. The connection beam portion 30 connects the intermediate ring portions 13 and 14 at the center of the protrusions 13b and 14b in the width direction. It is preferable that the protrusions 13b and 14b be provided as close to each other as possible in manufacturing on both sides of the width of the connection beam portion 30. It is also possible to provide the protrusions 13b and 14b on one side in the width direction of the connecting beam 30. The connecting beam 30 is disposed in the center of the surface 42 in the width direction.

[0023] A slit-like gap 35 is formed between the protrusion 13b and the protrusion 14b. The shape of the connection beam 30 is determined by track-shaped holes 36 provided on both sides of the connection beam 30 in the width direction of the protrusions 13b, 14b and the slit-like gaps 35 communicating with the holes 36. The connection beam 30 has a straight portion 30a extending perpendicularly to the end 13a of the intermediate ring portion 13 and the end 14a of the intermediate ring portion 14. The length L and width H of the straight portion 30a of the connection beam 30 are determined by the holes 36 provided on both sides of the connection beam 30 in the width direction. Since the connection beam 30 bends the bending tube 1 in any direction, it is preferable that the connection beam 30 has flexibility that allows it to be bent and twisted in the thickness and width directions. Therefore, it is preferable that the length L and width of the straight portion 30a be appropriately set to dimensions that can withstand at least the maximum allowable deflection of the bending tube 1.

[0024] The slit-like gap 35 is made up of tip surfaces 13c, 14c that are narrow where the hole 36 connects and widen as they move away from the connecting beam portion 30. When the bending tube 1 is bent, the tip surfaces 13c and 14c come into contact with each other. The inclination angle and the distance of the gap 35 are defined so that the tip surfaces 13c and 14c have the maximum allowable deflection at the point where they come into contact with each other.

[0025] Although the bending tube 1 described in FIGS. 1 and 2 has protrusions 13b, 14b on both sides of each connecting beam in the width direction, it is possible to configure the bending tube 1 without the protrusions 13b, 14b. In such a configuration, the distance between the end 13a of the intermediate ring portion 13 and the end 14a of the intermediate ring portion 14 is sufficient to allow the end 13a to abut against the end 14a of the intermediate ring portion 14 when the bending tube 1 is bent to the maximum allowable deflection. However, in such a configuration, the end 13a and the end 14a may overlap as the bending tube 1 is bent, causing the maximum allowable deflection to be exceeded. Therefore, by providing a bent portion (not shown) in the thickness direction on at least one of the end 13a and the end 14a, it is possible to prevent the intermediate ring portion 13 and the intermediate ring portion 14 from overlapping. This bent portion is preferably provided in the center between the connecting beam portion 30 and the connecting beam portion 31 (see FIG. 1).

[0026] The maximum allowable deflection here means that when the bendable tube 1 is bent, the connecting beam portions 30-33 are within their elastic limits and can return to their original shape after bending, or that the connecting beam portions 30-33 are within a deflection range that will not break even if the bending operation is repeated a predetermined number of times. Next, a method for manufacturing the bendable tube 1 will be described with reference to FIG.

[0027] (Manufacturing method of bending tube 1) FIG. 3 is a diagram illustrating a manufacturing method of a bending tube 1 according to a first example. First, as shown in FIG. 3(a), in a punching process, a punch and a die (not shown) are used to punch out an expanded forming plate 51 having the shape of the bending tube 1 when flatly expanded from a metal plate 50 serving as a raw material. The metal plate 50 serving as a raw material is preferably a thin plate having a thickness of, for example, 0.3 mm and made of flexible stainless steel, and is preferably a long material that can be continuously punched. Arranged on the expanded forming plate 51 are, in order from the left side in the figure, a distal ring portion 11, intermediate ring portions 12-22, and a proximal ring portion 23. Adjacent ring portions 10 are alternately connected so that connection beam portions 30, 31 and connection beam portions 32, 33 are in the front and rear positions in the longitudinal direction of the bending tube 1 (see also FIG. 1).

[0028] In Figure 3(a), the horizontal line shown by the two-dot chain line indicates the position of the folding line 52 for forming the developed forming plate 51 into an octagonal cylindrical shape, and the areas sandwiched between the two folding lines 52 become surfaces 41 to 48. Furthermore, an end face 51a at the upper end side and an end face 51b at the lower end side in the figure of the developed forming plate 51 become joints 53 when forming the developed forming plate 51 into a cylindrical shape (see Figure 3(b)). Note that surface 41 is divided into an upper end side and a lower end side in the figure, and surface 41 is formed by joining them when forming the developed forming plate 51 into an octagonal cylindrical shape. Next, the developed forming plate 51 is formed into a cylindrical shape in a forming process.

[0029] FIG. 3(b) is a cross-sectional view showing the forming process for forming the developed forming plate 51 into a cylindrical shape. First, the developed forming plate 51 is bent at the bending line 52 using a punch (not shown) or the like. Then, an octagonal forming jig 54 that can be inserted into the bending tube 1 is set inside the bent developed forming plate 51, and the developed forming plate 51 is pressed against the forming jig 54 from the outer periphery using a forming jig or a type of clamping mechanism (not shown). This brings the end faces 51a and 51b of the divided surface 41 into close contact. In this state, the end faces 51a and 51b are fixed to each other using a fixing means (fixing step). Suitable fixing means include laser welding. However, the fixing means is not limited to laser welding; for example, multi-point spot welding can also be used. In this manner, the bending tube 1 is formed into an octagonal cylindrical shape. Thereafter, the pressure applied by the forming jig is released, and the forming jig 54 is removed, completing the bending tube 1.

[0030] The bending tube 1 according to the first example described above is composed of a plurality of cylindrical ring portions 10 spaced apart in the longitudinal direction, and bendable connection beam portions 30, 31, 32, and 33 that connect adjacent ring portions 10. The connection beam portions 30, 31 and the connection beam portions 32, 33 are provided at two opposing positions in the circumferential direction of adjacent ring portions 10. The connection beam portions 32 and 33 are positioned at positions offset by 90 degrees from the connection beam portions 30, 31, respectively. With this configuration, when attempting to bend the bending tube 1, the connection beam portions 30, 31, 32, and 33 can bend easily, and because they are arranged in a balanced manner between the adjacent ring portions, it is possible to bend the bending tube 1 freely in any direction with low load.

[0031] Furthermore, the bending tube described in the above prior art has independently formed ring members connected by two hinge sections (hinge mechanisms) that are 180 degrees apart. In contrast, the bending tube 1 has multiple ring sections 10 and connecting beam sections 30-33 integrally configured, so there is only one component, and the manufacturing process can be shortened, making it possible to significantly reduce manufacturing costs compared to the prior art.

[0032] The bending tube 1 has the same configuration at each stage of adjacent ring sections 10. For example, in the case of the intermediate ring section 13 and the intermediate ring section 14, a protrusion 13b is provided protruding from the end 13a of the intermediate ring section 13 toward the adjacent intermediate ring section 14, and a protrusion 14b is provided from the end 14a of the intermediate ring section 14 toward the adjacent intermediate ring section 13. The protrusions 13b, 14b are formed immediately adjacent to the connecting beam section 30 in the width direction. The bending tube 1 has a gap 35 between the protrusions 13b and 14b that can restrict the maximum allowable deflection when the bending tube 1 is bent. In other words, when the bending tube 1 is bent until the distal end surface 13c of the protrusion 13b and the distal end surface 14c of the protrusion 14b abut against each other, the bending tube 1 falls within the range of the maximum allowable deflection. Therefore, the bending tube 1 can be repeatedly bent within a predetermined bending range.

[0033] Furthermore, since the protrusions 13b, 14b are arranged in close proximity to both sides of the connecting beam 30 in the width direction, it is possible to prevent the protrusions 13b and 14b from overlapping each other when bending the bending tube 1. Therefore, it is possible to prevent the bending tube 1 from being bent beyond the allowable bending deflection, and it is possible to provide the required durability.

[0034] The bending tube 1 (ring portion 10) shown in the first example has a regular octagonal cross section (sliced ​​shape). That is, the bending tube 1 is composed of eight faces, 41 to 48. Explaining using the example shown in FIGS. 1 to 3, the ring portion 10 has a connecting beam portion 30 on face 42 and a connecting beam portion 31 on face 46 directly opposite face 42, which is offset by 180 degrees from face 42. The connecting beam portion 32 is then arranged on face 44, which is offset by 90 degrees from face 42, and a connecting beam portion 33 on face 48 directly opposite face 44. With this configuration, the connecting beam portions 30, 31, 32, and 33 can be alternately arranged at 90-degree intervals in a balanced manner, and the bending tube 1 can be freely bent in any direction.

[0035] Furthermore, since the connecting beam portions 30, 31, 32, and 33 are formed on the inside of the surfaces 42, 44, 46, and 48, respectively, they can be formed into a cylindrical shape without affecting the shape of each connecting beam portion.

[0036] The cross-sectional shape of the bending tube 1 is not limited to an octagon, and can also be a circle or an n-gon (n is an even number). A circular cross-sectional shape has the advantage of increasing the degree of freedom in the placement position of each connecting beam. However, due to the influence of springback, it is not easy to form a distortion-free circle. When the cross-sectional shape is an n-gon, if each connecting beam is formed within a plane, it is possible to arrange the connecting beams so that they face each other by making the number of faces an even number. Furthermore, when the cross-sectional shape is a polygon, it is possible to easily form it into a cylindrical shape by creating a bending tendency along the bending line 52.

[0037] Furthermore, the connecting beams 30-33 are arranged at equal angular intervals in the circumferential direction between adjacent ring portions. The connecting beams (connecting beams 30, 31) between adjacent ring portions 10 in the preceding stage (for example, the distal ring portion 11 and the intermediate ring portion 12) are arranged with a shifted position in the circumferential direction for the connecting beams (connecting beams 32, 33) between adjacent ring portions 10 in the succeeding stage (for example, the intermediate ring portion 12 and the intermediate ring portion 13). By arranging the connecting beams 30, 31 and the connecting beams 32, 33 in this manner, the bending tube 1 can be bent in any direction while suppressing differences in load depending on the bending direction.

[0038] In addition, in the manufacturing method of the bent tube 1 described above, first, an expanded forming plate 51 that will become the expanded shape of each ring portion 10 is punched out from a metal plate 50. Next, the punched expanded forming plate 51 is bent along bending lines 52, and then formed into a cylindrical shape using a molding jig 54 or a forming jig (not shown), and joined at a joint 53. Because the bent tube 1 is manufactured using this process, it has only one component, and the manufacturing process can be shortened, making it possible to significantly reduce manufacturing costs compared to conventional techniques.

[0039] To explain this using adjacent intermediate ring portions 13, 14 as an example, the bending tube 1 according to the first example has connecting beam portions 30, 31 that connect between the intermediate ring portion 13 and the intermediate ring portion 14. The connecting beam portions 30, 31 have straight portions 30a that connect the intermediate ring portion 13 and the intermediate ring portion 14. On both sides of the width direction of the connecting beam portions 30, 31, protruding portions 13b, 14b are provided to form degree contacts (also called surface contacts) when the bending tube 1 is bent. In contrast to this configuration, the bending tube 1 may not have the protruding portions 13b, 14b and may have connecting beam portions that are configured as curves; this configuration will be described as a second example with reference to FIGS. 4 and 5.

[0040] (Configuration of bending tube 1, second example) The bending tube 1 according to the second example differs from the first example shown in Figures 1 to 3 in that the shapes of the connecting beam portions 30 to 33 are different, and therefore the shapes of the ring portions 10 are different, but the arrangement of the connecting beam portions 30 to 33 and the cross-sectional shape of an octagonal cylinder remain unchanged. Therefore, the following description will focus on the differences.

[0041] FIG. 4 is a plan view showing the developing plate 61 of the bending tube 1 according to the second example. FIG. 4 is a development view of the connecting beam portions 30, 31, 32, and 33 punched out of a metal plate 50, which is the raw material. The manufacturing method of the developing plate 61 is the same as that of the first example. The developing plate 61 is arranged in the following order from the left side of the figure: the distal ring portion 11, the intermediate ring portions 12-20, and the proximal ring portion 25. In FIG. 4, components that can be described in the same manner as those of the bending tube 1 of the first example are given the same reference numerals as those in FIGS. 1-3. In addition, the ring portions may be collectively referred to as the ring portion 10. The proximal ring portion 25 is a portion that serves as a fulcrum when bending the bending tube 1. In addition, the distal ring portion 11 is a portion that swings when bending the bending tube 1 around the proximal ring portion 23 as a fulcrum. A lens or a working tool can be attached to the distal ring portion 11, or a working tool can be inserted into the bending tube 1 to swing the distal ring portion 11.

[0042] Among the multiple ring portions 10, adjacent ring portions 10 are connected by connecting beam portions 30, 31, 32, and 33 which can be bent. The connecting beam portions 30 to 33 and the ring portions 10 are integrally formed. As in the first example, the bent tube 1 according to the second example is formed into a cylindrical shape having a regular octagonal cross section, and therefore is composed of eight faces defined by bending lines 52 (shown by two-dot chain lines) formed when forming into a cylindrical shape. The faces are designated as faces 41, 42, 43, 44, 45, 46, 47, and 48. Face 41 is divided into two, an upper end side and a lower end side as shown in the figure, and end face 51a and end face 51b are joined when forming into an octagonal cylindrical shape, forming a flat surface similar to the other faces 42 to 48.

[0043] When molded into a cylindrical shape, the adjacent tip ring portion 11 and intermediate ring portion 12 are connected by a connecting beam portion 30 formed around surface 41 and spanning surfaces 42 and 48, and a connecting beam portion 31 formed around surface 45 and spanning surfaces 44 and 46. Surfaces 41 and 45 are arranged at 180-degree intervals in the circumferential direction when molded into a cylindrical shape. In other words, connecting beam portion 30 and connecting beam portion 31 are in an opposing positional relationship. The adjacent intermediate ring portion 12 and intermediate ring portion 13 are connected by a connecting beam portion 32 formed around surface 43 and spanning surfaces 42 and 44, and a connecting beam portion 33 formed around surface 47 and spanning surfaces 46 and 48. Surfaces 43 and 47 are arranged at 180-degree intervals in the circumferential direction when molded into a cylindrical shape. In other words, connecting beam portion 32 and connecting beam portion 33 are in an opposing positional relationship. The connecting beams 32 and 33 are arranged at 90° intervals from the connecting beams 30 and 31 in the circumferential direction.

[0044] Adjacent intermediate ring portions 13 and 14 are connected by connecting beam portions 30 and 31, and adjacent intermediate ring portions 14 and 15 are connected by connecting beam portions 32 and 33. Adjacent intermediate ring portions 15 and 16, intermediate ring portions 17 and 18, and intermediate ring portions 19 and 20 are connected by connecting beam portions 30 and 31, respectively. Adjacent intermediate ring portions 16 and 17, intermediate ring portions 18 and 19, and intermediate ring portion 20 and base end ring portion 25 are connected by connecting beam portions 32 and 33, respectively.

[0045] An end face 51a on the upper end side and an end face 51b on the lower end side of the developed forming plate 61 in the drawing become joints 53 when the developed forming plate 51 is formed into a cylindrical shape (see FIG. 3(b)). The surface 41 is divided into an upper end side and a lower end side in the drawing, which are joined together when the developed forming plate 51 is formed into a cylindrical shape to form the surface 41. Similarly, the connecting beam portion 30 is divided into an upper end side and a lower end side in the drawing in the developed forming plate 61, which are joined together when the developed forming plate 51 is formed into a cylindrical shape to form the connecting beam portion 30. The configuration of the connecting beam portions 30 to 33 in the second example will be described with reference to FIG. 5.

[0046] FIG. 5 is an enlarged plan view of a portion of the expanded shaping plate 61 according to the second example. Since the connecting beams 30 to 33 have the same shape but different arrangements, only the connecting beam 32 connecting the intermediate ring portion 14 and the intermediate ring portion 15 will be described. The connecting beam 32 is formed across the surfaces 42, 43, and 44. As shown in FIG. 5, the connecting beam 32 is composed of beams 65 and 66 extending from the intermediate ring portion 14 and beams 67 and 68 extending from the intermediate ring portion 15. The beam 65 has a J-shape that extends from the surface 42 to the surface 43, starting from the end 14a of the intermediate ring portion 14 on the intermediate ring portion 15 side. The beam 66 has a J-shape that extends from the surface 44 to the surface 43, starting from the end 14a. The ends of the shorter sides of the J-shape of the beams 65 and 66 are connected to semicircular connecting portions 65a and 66a, respectively, and the semicircular connecting portions 65a and 66a are connected to the central connecting portion 70 on the side of the intermediate ring portion 14.

[0047] Beam portion 67 has a J-shape that starts at end portion 15a of intermediate ring portion 15 on the intermediate ring portion 14 side and extends from surface 42 to surface 43. Beam portion 68 has a J-shape that starts at end portion 15a and extends from surface 44 to surface 43. Beam portions 67 and 68 are each connected to semicircular connecting portions 67a, 68a at the ends of the shorter sides of the J-shape, and semicircular connecting portions 67a, 68a are connected to central connecting portion 70 on the intermediate ring portion 15 side.

[0048] The beams 65, 66 and the beams 67, 68 are symmetrical with respect to a center line P2 and a center line P3 that pass through the center of the central connecting portion 70. The center line P2 is a line that divides the central connecting portion 70 into two in the length direction (left-right direction in the figure) of the unfolding forming plate 61. The center line P3 is a line that is perpendicular to the center line P2 and divides the central connecting portion 70 into two in the width direction (up-down direction in the figure) of the unfolding forming plate 61. The gap 71 between the end 14a of the intermediate ring portion 14 and the end 15a of the intermediate ring portion 15 determines the maximum allowable deflection when the bending tube 1 is bent until the end portions 14a, 15a abut. The beams 65, 66, 67, 68 are flexible within the range of the maximum allowable deflection. Although not shown, it is preferable to provide a bent portion or the like in the thickness direction on at least one of the end 14a of the intermediate ring portion 14 and the end 15a of the intermediate ring portion 15. By providing the bending and raising portion, it is possible to prevent the intermediate ring portion 14 and the intermediate ring portion 15 from overlapping when the bending tube 1 is bent, and to prevent bending beyond the maximum allowable deflection.

[0049] The manufacturing method of the bending tube 1 according to the second example can be performed in the same process as the first example (see FIG. 3), so a detailed description will be omitted here. The unfolded forming plate 61 is formed into an octagonal cylindrical shape at the position of the bending line 52. Referring to FIG. 5, the bending line 52 passes between the central connection portion 70 and, for example, the bases 72a and 73a of the beam portions 72 and 73 of the connecting beam portion 30, and therefore does not affect the bending operation of the bending tube 1. Furthermore, since the other bending lines 52 pass through the middle of the beam portions 65 and 67 and the beam portions 66 and 68 in the longitudinal direction, it is conceivable that they may affect the bending operation. However, because the beam portions 65 to 68 are sufficiently long relative to their width, the effect on the bending operation is kept to a negligible level. The positional relationship between the other bending lines 52 and the connecting beam portions 31, 32, and 33 is also the same.

[0050] In the bending tube 1 of the second example, the beam portions 65 to 68 that make up the connecting beam portions 30 to 33 are much longer than the straight portion 30a of the first example that corresponds to the beam portions 65 to 68, and are flexible within the range of the maximum allowable deflection, so there is no risk of damage even if the bending operation is repeated in any direction.

[0051] In the second example, adjacent ring portions 10 have gaps 71 that can restrict bending deflection within the range of maximum allowable deflection when the bent tube 1 is bent. Explaining with reference to Fig. 5, a gap 71 is provided between the opposing end portions 14a of adjacent intermediate ring portions 14 and 15. When the bent tube 1 is bent, if the point where the end portions 14a and 15a abut is within the bending allowable deflection range, there is no risk of the bent tube 1 being damaged.

[0052] In the connecting beam sections 30-33 of the bent tube 1 according to the first example, the substantial bending portion is configured as a straight section 30a, whereas in the connecting beam sections 30-33 of the bent tube 1 according to the second example, the beam sections 65-68 are configured by a combination of straight and curved lines. With this configuration, the beam sections 65-68 can be easily bent in any direction with a low load, and the range of allowable bending deflection can be expanded. Also, although the beam sections 65-68 each have a J-shape, it is also possible to curve the long side of the J-shape and configure the connecting beam sections 30-33 by a combination of curved lines, which makes it possible to make them easier to bend with a low load than straight lines alone or a combination of straight lines and curved lines.

[0053] (Variation 1) FIG. 6 is an enlarged view of a portion of the bending tube 1 according to Modification 1. Modification 1 can be considered a modification of the first example described above. Therefore, in FIG. 6, the same functional parts as in FIG. 2 are assigned the same reference numerals. Note that the connecting beam portions 30-33 have the same configuration although their arrangements are different, so the connecting beam portion 30 connecting the adjacent intermediate ring portion 13 and intermediate ring portion 14 will be described as an example. The intermediate ring portion 13 and the intermediate ring portion 14 are connected by the connecting beam portion 30 protruding from each of the opposing end portions 13a, 14a. A protrusion 13b is provided on the intermediate ring portion 13 protruding toward the intermediate ring portion 14. Furthermore, a protrusion 14b is provided on the intermediate ring portion 14 protruding toward the intermediate ring portion 13.

[0054] A slit-like gap 35 is formed between the protrusions 13b and 14b. The connecting beam 30 has a straight portion 30a that extends at an angle relative to the end 13a of the intermediate ring portion 13 and the end 14a of the intermediate ring portion 14. Since the connecting beam 30 bends the bending tube 1 in any direction, it is preferable that the connecting beam 30 has flexibility that allows it to be bent or twisted in the thickness direction and width direction. By inclining the straight portion 30a relative to the end portions 13a, 14a, the length L1 of the straight portion 30a in Modification 1 can be made longer than the length L of the straight portion 30a in the first example (see FIG. 2), and it becomes possible to easily bend the bending tube 1 with a low load when bending.

[0055] As the bending tube 1 is bent, the distal end surface 13c of the protrusion 13b and the distal end surface 14c of the protrusion 14b come into contact with each other. The gap 35 is defined so that the point where the distal end surfaces 13c and 14c come into contact with each other is the maximum allowable deflection. Therefore, the length L1 and width H1 of the gap 35 and the connecting beam 30 are appropriately defined so as to fall within the range of the maximum allowable deflection of the bending tube 1. It is preferable that the protrusions 13b and 14b be located as close to the straight portion 30a as possible without affecting the deflection of the straight portion 30a. In addition, although the protrusions 13b and 14b are located on one side of the straight portion 30a in the width direction in FIG. 6, they can also be located on both sides of the straight portion 30a in the width direction. However, it is preferable that the protrusions 13b and 14b be located within the surface 42.

[0056] In the bending tube 1 according to the first modification described above, the length L1 of the straight portions 30a constituting each connecting beam portion can be set to L1 >> L, relative to the length L of the straight portions 30a according to the first example. This makes it possible to expand the range of maximum allowable deflection. In other words, since it is possible to make the bending tube 1 have a length that allows flexibility within the range of maximum allowable deflection, there is no risk of breakage even when bending operations are repeated. Furthermore, since the first modification can be manufactured using the same manufacturing method as the bending tube 1 of the first example, there is no increase in the manufacturing load.

[0057] In addition, in the first modification, the inclination direction of the straight line portion 30a on the surface 46 opposite the surface 42 may be a direction that intersects with the inclination direction on the surface 42. Furthermore, the inclination direction of the straight line portion 30a between the intermediate ring portion 15 and the intermediate ring portion 16 may be changed to a direction that intersects with the inclination direction of the straight line portion 30a between the intermediate ring portion 14 and the intermediate ring portion 15. In other words, the direction of the straight line 30a may be alternately changed for each adjacent ring portion 10.

[0058] (Variation 2) FIG. 7 is a diagram showing a portion of the unfolded shaping plate 61 according to Modification 2. Modification 2 can be considered a modification of the second example described above. Therefore, in FIG. 7, the same functional parts as in the second example are denoted by the same reference numerals as in FIG. 4. Since the connecting beams 30-33 have the same configuration but different arrangements, the following description will focus on the connecting beam 30 connecting the adjacent intermediate ring portions 14 and 15. The intermediate ring portions 14 and 15 are connected by connecting beams 32 protruding from the opposing ends 14a and 15a of the intermediate ring portions 14 and 15. The connecting beam 32 is composed of U-shaped beams 75 and 76. The beam 75 is connected to the intermediate ring portions 14 and 15 at two bases 75a on the long sides of the U-shape. The beam 76 is connected to the intermediate ring portions 14 and 15 at two bases 76a on the long sides of the U-shape. The beam portion 75 and the beam portion 76 are disposed in a position where their respective tops 75b, 76b are close to each other. The tops 75b, 76b are spaced apart so that they do not come into contact with each other when the bending tube 1 is bent.

[0059] Furthermore, between the intermediate ring portion 14 and the intermediate ring portion 15, the inner end surface 80a of the hole portion 80 that forms the beam portions 75, 76 is located in a position that does not come into contact with the beam portions 75, 76 when the bending tube 1 is bent.

[0060] The gap 71 between the end 14a of the intermediate ring portion 14 and the end 15a of the intermediate ring portion 15 determines the maximum allowable deflection when the bending tube 1 is bent until the end portions 14a, 15a abut. The beam portions 75, 76 are flexible within the range of the maximum allowable deflection. Although not shown, it is preferable to provide a bent portion or the like in the thickness direction on at least one of the end 14a of the intermediate ring portion 14 and the end 15a of the intermediate ring portion 15. By providing the bent portion, it is possible to prevent the intermediate ring portions 14 and 15 from overlapping when the bending tube 1 is bent, and to prevent bending beyond the maximum allowable deflection. Alternatively, a configuration may be adopted in which protrusions similar to the protrusions 13b, 14b shown in the first example (see FIG. 2) and the first modified example (see FIG. 6) are provided near the base portions 75a, 76a.

[0061] The bending tube 1 according to the second modification can be manufactured using the same process as in the first example (see FIG. 3), and therefore a detailed description thereof will be omitted here. The unfolded molding plate 61 is formed into an octagonal cylindrical shape at the position of the bending line 52. The bending line 52 is disposed between the apex 75b of the beam portion 75 and the apex 76b of the beam portion 76, near the bases of the beam portions 75, 76. The other bending lines 52 also have the same positional relationship with the connecting beam portions 30, 31, 33. By positioning the bending line 52 between the apex 75b and the apex 76b and the bending line 52 near the bases of the beam portions 75, 76, the bending operation of the bending tube 1 is not affected by the position of the bending line 52.

[0062] In the bending tube 1 according to the second modification, although the configuration of the connecting beam portions 30 to 33 is different from that of the second example, the beam portions 75 and 76 are U-shaped, and therefore the substantial elastic limit length is longer than that of the beam portions 65, 66, 67, and 68 of the second example. As a result, bending in any direction can be performed with low load, and there is no risk of breakage even if bending in any direction is repeated. Furthermore, in the second modification, the shapes of the beam portions 75 and 76 are simpler than those of the second example, and therefore the molds and jigs (e.g., dies and punches) required to manufacture the unfolding shaping plate 61 can be simplified in configuration, reducing manufacturing costs for the molds and jigs and facilitating maintenance.

[0063] In Modification 2, the beams 75 and 76 are arranged so that their respective apexes 75b and 76b are close to each other, but it is also possible to arrange the beams 75 and 76 side by side so that they face the same direction. For example, in the case of the connecting beam 32, it is also possible to configure the beams with only one of the beams 75 and 76. In that case, the beams may be arranged so that their positions are alternated for each ring 10 to be connected.

[0064] The bending tube 1 of each example described above can be suitably used for, for example, a bending movable portion at the tip of an endoscope, fiberscope, or the like. [Explanation of symbols]

[0065] 1...Bending tube, 10...Ring portion (generic name), 11...Tip ring portion, 12-22...Middle ring portion, 23, 25...Base ring portion, 13a, 14a, 15a...End portion, 13b, 14B...Protrusion portion, 30-33...Connecting beam portion, 35, 71...Gap, 41-48...Surface, 50...Metal plate, 51, 61...Expanded forming plate, 65-68, 72, 73, 75, 76...Beam portion, P...Central axis

Claims

1. A bending tube in which a flexible metal plate is formed into a cylindrical shape and can be bent freely, a plurality of ring portions spaced apart from one another in the longitudinal direction; a bendable connecting beam portion connecting adjacent ring portions; and The connecting beam portions are arranged at at least two locations facing each other in the outer circumferential direction of the ring portion. A curved pipe characterized by:

2. The bending tube according to claim 1, A gap is provided between the ends of the adjacent ring portions, which can restrict bending deflection when the bending tube is bent to within a range of maximum allowable deflection. A curved pipe characterized by:

3. The bending tube according to claim 1, a protrusion protruding from an end of the ring portion toward the adjacent ring portion; the protrusion is formed immediately adjacent to the connection beam in the width direction, The projections of the adjacent ring portions are spaced apart from one another to restrict the maximum allowable deflection when the bending tube is bent. A curved pipe characterized by:

4. The bending tube according to claim 1, The ring portion has a circular or n-sided (n is an even number) cross-sectional shape. A curved pipe characterized by:

5. The bending tube according to claim 1, the connecting beam portions are arranged at equal angular intervals around the central axis of the ring portion, The connecting beam portions between the adjacent ring portions in the subsequent stage are arranged so as to be shifted in position in the circumferential direction relative to the connecting beam portions between the adjacent ring portions in the previous stage. A curved pipe characterized by:

6. The bending tube according to claim 1, The connecting beam portion is formed by a straight line, a curved line, or a combination of a straight line and a curved line. A curved pipe characterized by:

7. The method for manufacturing a bending tube according to any one of claims 1 to 6, a punching step of punching out an expanded shaped plate including the connection beam portion and the ring portion from the flexible rectangular metal plate; a forming step of forming the punched developed molded plate into a cylindrical shape; a fixing step of fixing two sides of the development molding plate that come into contact when the development molding plate is formed into a cylindrical shape; Including, A method for manufacturing a curved tube.

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