Medical tube, endoscope, and production method for medical tube

Abstract

A medical tube 30 has a first resin layer 32 that extends from a distal end to a proximal end along an axis A, a first helical layer 35 that is provided at the outer circumference of the first resin layer and is formed by helically winding a first wire 35a along a first direction, and a second helical layer 36 that is provided at the outer circumference of the first helical layer and is formed by helically winding a second wire 36a along a second direction that intersects the first direction. The first helical layer 35 includes a first portion A1 at which the first wire 35a has been wound at a first pitch P1 and a second portion A2 at which the first wire 35a has been wound at a second pitch P2 that is smaller than the first pitch P1, and the second helical layer 36 includes a third portion A3 at which the second wire 36a has been wound at a third pitch P3 and a fourth portion A4 at which the second wire 36a has been wound at a fourth pitch P4 that is smaller than the third pitch P3. The fourth portion A4 is provided at the outer circumference of the first portion A1, and the second portion A2 and the fourth portion A4 are each in contact with an outer circumferential surface of the first resin layer 32.

Description

Medical Tube, Endoscope, and Method for Manufacturing Medical Tube

[0001] The present invention relates to a flexible medical tube, an endoscope using the medical tube, and a method for manufacturing a medical tube.

[0002] Conventionally, endoscopes are used to observe a target site inside a subject such as a body cavity, and to perform various treatments on the target site as needed. As endoscopes, flexible endoscopes in which an insertion portion includes a distal end portion, a bending portion, and a flexible tube portion are widely used.

[0003] The flexible tube portion of a flexible endoscope is configured using a flexible medical tube. As this type of medical tube, a blade tube formed by braiding metal strands into a cylindrical shape is widely used. Furthermore, for example, Patent Document 1 discloses a flexible portion (medical tube) of an endoscope formed by winding a plurality of layers of metal strands in a spiral shape around the outer circumference of a strip-shaped spiral tube. Further, Patent Document 1 discloses a technique in which diffusion bonding is performed on a metal strand cylindrical body formed by winding metal strands and a strip-shaped spiral body, and overlapping portions of each member are bonded.

[0004] Japanese Patent No. 6100506

[0005] However, as in the technique disclosed in Patent Document 1 mentioned above, bonding of metal strands or the like using diffusion bonding requires a predetermined amount of time, which may reduce the productivity of medical tubes. On the other hand, in order to maintain appropriate flexibility of the medical tube, it is particularly necessary to suppress axial displacement of each spirally wound metal strand.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a medical tube, an endoscope, and a method for manufacturing a medical tube that are excellent in productivity and can maintain appropriate flexibility performance.

[0007] A medical tube according to one aspect of the present invention includes a first cylindrical layer extending along an axis from the tip to the base, a first helical layer disposed on the outer circumference of the first cylindrical layer and having first strands formed spirally along a first direction, and a second helical layer disposed on the outer circumference of the first helical layer and having second strands formed spirally along a second direction intersecting the first direction, wherein the first helical layer includes a first portion in which the first strands are wound at a first pitch and a second portion in which the first strands are wound at a second pitch that is denser than the first pitch, and the second helical layer includes a third portion in which the second strands are wound at a third pitch and a fourth portion in which the second strands are wound at a fourth pitch that is denser than the third pitch, wherein the third portion is disposed on the outer circumference of the second portion and the fourth portion is disposed on the outer circumference of the first portion, and the second portion and the fourth portion are in contact with the circumferential surface of the first cylindrical layer, respectively.

[0008] An endoscope according to one aspect of the present invention includes: a first cylindrical layer extending along an axis from the tip to the base; a first helical layer disposed on the outer circumference of the first cylindrical layer and having first strands formed spirally along a first direction; and a second helical layer disposed on the outer circumference of the first helical layer and having second strands formed spirally along a second direction intersecting the first direction, wherein the first helical layer includes a first portion in which the first strands are wound at a first pitch and a second portion in which the first strands are wound at a second pitch that is denser than the first pitch; the second helical layer includes a third portion in which the second strands are wound at a third pitch and a fourth portion in which the second strands are wound at a fourth pitch that is denser than the third pitch, wherein the third portion is disposed on the outer circumference of the second portion and the fourth portion is disposed on the outer circumference of the first portion, and the second portion and the fourth portion each include a medical tube in the insertion portion that is in contact with the circumferential surface of the first cylindrical layer.

[0009] A method for manufacturing a medical tube according to one aspect of the present invention includes the steps of: forming a first portion by spirally winding a first wire at a first pitch along a first direction around an axis; forming a second portion by spirally winding the first wire at a second pitch that is denser than the first pitch along the first direction; forming a third portion on the outer circumference of the second portion by spirally winding a second wire at a third pitch along a second direction intersecting the first direction; forming a fourth portion on the outer circumference of the first portion by spirally winding the second wire at a fourth pitch that is denser than the third pitch along the second direction; and forming a first cylindrical layer having a circumferential surface that contacts the second portion and the fourth portion.

[0010] According to the present invention, it is possible to achieve excellent productivity while maintaining appropriate flexibility.

[0011] The following embodiments are described: a perspective view showing the external appearance of an endoscope; a cross-sectional view showing the main part of the insertion section along the central axis; a perspective view showing a medical tube; a cross-sectional view showing the IV-IV section of Figure 3; a cross-sectional view showing the V-V section of Figure 3; a flowchart showing the manufacturing process of a medical tube; a perspective view showing the coating process of the first resin layer; a perspective view showing the formation process of the first helical layer; a perspective view showing the formation process of the first helical layer; a perspective view showing the formation process of the second helical layer; and a diagram showing the formation process of the second helical layer. This relates to a modified example of the perspective view embodiment, a modified example of the cross-sectional view embodiment showing the medical tube along the central axis, a modified example of the perspective view embodiment showing the medical tube, a modified example of the cross-sectional view embodiment between XIV and XIV in Figure 13, a modified example of the cross-sectional view embodiment between XV and XV in Figure 13, a modified example of the flowchart embodiment showing the manufacturing process of the medical tube, a modified example of the perspective view embodiment showing the coating process of the second resin layer, a modified example of the cross-sectional view embodiment showing the medical tube along a direction perpendicular to the central axis, and a cross-sectional view embodiment showing the medical tube along a direction perpendicular to the central axis.

[0012] The embodiments of the present invention will now be described with reference to the drawings. The drawings relate to one embodiment of the present invention, and Figure 1 is a perspective view showing the external appearance of the endoscope. In the following description, the drawings based on each embodiment are schematic. It should also be noted that the relationship between the thickness and width of each component of the endoscope, the ratio of the thickness of each component, etc., may differ from those of reality. Furthermore, even among the components of the endoscope shown in the drawings, there may be parts where the dimensional relationships and ratios of each component differ from those of the other.

[0013] The endoscope 1 shown in Figure 1 is, for example, an endoscope for the renal pelvis and urinary tract (renal pelvis ureteroscope). This endoscope 1 is a single-use type in which, for example, all or at least some of the parts of the endoscope 1 are disposed of after a single use. The endoscope 1 comprises an elongated insertion section 2 that is inserted into the body cavity of the subject, an operating section 3 provided at the base end of the insertion section 2, and a universal cable 4 extending from the base end of the operating section 3.

[0014] As shown in Figure 1, the insertion portion 2 has a tip portion 6, a curved portion 7, and a flexible tube portion 8. These tip portion 6, curved portion 7, and flexible tube portion 8 are arranged in order from the tip side of the insertion portion 2.

[0015] The tip portion 6 is provided with an imaging unit 10, an illumination optical system (not shown), and a treatment tool channel opening, etc.

[0016] The curved section 7 is configured to actively curve vertically in response to operational input from the operator or other user to the control unit 3. In this embodiment, the front-rear, left-right, and right directions of the insertion section 2 are defined in relation to the images captured by the imaging unit 10.

[0017] Specifically, the curved section 7 has a set of curved pieces arranged in a row, which are not shown. In this set of curved pieces, adjacent curved pieces are connected by a pair of left and right axes so that they can rotate relative to each other. In addition, a wire guide is provided on a predetermined curved piece. One of a pair of upper and lower traction wires 12 is inserted through each wire guide. Each traction wire 12 is pulled or released in response to an operation input from the operator or others to the operation unit 3. This makes it possible to curve the curved section 7 in the vertical direction.

[0018] Inside the curved frame assembly configured in this way, internal components such as the signal cable 11 extending from the imaging unit 10, the traction wire 12, the light guide 13, and the treatment instrument channel 14 are inserted. The outer circumference of the curved frame assembly is covered with curved rubber.

[0019] As shown in Figure 4, the flexible tube section 8 is constructed using a medical tube 30 (described later) that is flexible and can be bent passively. The medical tube 30 contains internal components such as the signal cable 11, traction wire 12, light guide 13, and treatment instrument channel 14. The outer circumference of the medical tube 30 is covered by an outer sheath 15.

[0020] The operating section 3 includes a bend-stopping section 20, a gripping section 21, and the operating section body 22.

[0021] The anti-folding portion 20 is connected to the flexible pipe portion 8 in a state that it covers the base end of the flexible pipe portion 8.

[0022] The gripping portion 21 is connected to the base end of the anti-folding portion 20. This gripping portion 21 is shaped to be grasped by the hand of a surgeon or other operator.

[0023] A treatment instrument insertion section 23 is provided at the tip of the gripping section 21. The treatment instrument insertion section 23 is configured to have a treatment instrument insertion opening 23a through which various treatment instruments (not shown) can be inserted. Inside the gripping section 21, the base end of the treatment instrument channel 14 is in communication with the treatment instrument insertion opening 23a. Furthermore, a forceps plug (not shown), which is a lid member for closing the treatment instrument insertion opening 23a, is detachably attached to the treatment instrument insertion section 23.

[0024] The operating unit body 22 is connected to the base end of the gripping unit 21. The operating unit body 22 is provided with a bending lever 25. The bending lever 25 is used to bend the bending unit 7 in the vertical direction by pulling or releasing a pair of traction wires 12.

[0025] In other words, for example, when the bending lever 25 is tilted toward the tip of the operating section 3, one of the pair of towing wires 12, the upper towing wire 12, is pulled, and the other towing wire 12, the lower towing wire, is released. As a result, the bending section 7 bends upward. On the other hand, when the bending lever 25 is tilted toward the base end of the operating section 3, one of the pair of towing wires 12, the upper towing wire 12, is released, and the other towing wire 12, the lower towing wire, is pulled. As a result, the bending section 7 bends downward.

[0026] Furthermore, the control unit body 22 is equipped with a group of operation buttons 26 to which various functions of the endoscope 1 are assigned.

[0027] The universal cable 4 extends from the side of the control unit body 22. Various cables, such as the signal cable 11, and the light guide 13 are inserted inside the universal cable 4.

[0028] Furthermore, a connector 5 is provided at the extended end of the universal cable 4. This connector 5 allows various cables and light guides to be connected to the video processor and light source device (neither of which are shown in the illustration).

[0029] Next, the configuration of the medical tube 30 that constitutes the flexible tube portion 8 of the insertion portion 2 will be explained in detail.

[0030] As shown in Figures 3 to 5, the medical tube 30 has a tubular body 31 and a first resin layer 32 as a first cylindrical layer.

[0031] The tube 31 has a first helical layer 35 and a second helical layer 36. The first helical layer 35 and the second helical layer 36 are composed of a first strand 35a and a second strand 36a, respectively. The first strand 35a and the second strand 36a are composed of, for example, metal strands. The metal strands are preferably made of austenitic stainless steel, iron, or copper. However, the first strand 35a and the second strand 36a are not limited to metal strands, and may be made of resin strands or carbon wire, etc. Aramid is preferred for the resin strands. The resin strands are preferably made of nylon or polyester material, which has a higher heat resistance temperature than the resin forming the resin layer.

[0032] The first helical layer 35 is formed by spirally winding the first strand 35a along a first direction around the axis A (central axis) of the tube 31.

[0033] More specifically, the first helical layer 35 is formed by winding a first group of wires 35ag, which consists of a plurality (for example, three) of first wires 35a, in a helical shape.

[0034] As shown in Figure 2, the first helical layer 35 has a first portion A1 in which the first group of wires 35ag is wound at a first pitch P1, and a second portion A2 in which the first group of wires 35ag is wound at a second pitch P2 which is denser than the first pitch P1. These first portion A1 and second portion A2 are arranged alternately along the direction of axis A. Here, the first pitch P1 is defined in the first portion A1 in which the first group of wires 35ag is wound helically for multiple periods, based on the relationship between the helical period of interest (the earlier period) and other helical periods adjacent to the base end side of the helical period of interest (the later period). That is, the first pitch P1 is defined by the distance between the first wire 35a located at the base end of the first group of wires 35ag in the earlier period and the first wire 35a located at the tip of the first group of wires 35ag in the later period. Similarly, the second pitch P2 is defined in the second part A2, where the first group of wires 35ag is wound spirally for multiple periods, based on the relationship between the spiral period of interest (the earlier period) and other spiral periods adjacent to the base end of the spiral period of interest (the later period). That is, the second pitch P2 is defined by the distance between the first wire 35a located at the base end of the first group of wires 35ag in the earlier period and the first wire 35a located at the tip of the first group of wires 35ag in the later period.

[0035] In this embodiment, the first pitch P1 and the second pitch P2 are set to be different from the spacing between each first strand 35a constituting the first strand group 35ag. More specifically, the first pitch P1 and the second pitch P2 are set to be greater than the spacing between each first strand 35a constituting the first strand group 35ag. When the first helical layer 35 is formed by a single first strand 35a, the helical pitch of the first strand 35a becomes the first pitch P1 and the second pitch P2.

[0036] Furthermore, the first helical layer 35 is not limited to being formed by three first strands 35a. The first helical layer 35 can be formed using one or any number of first strands 35a.

[0037] The second helical layer 36 is formed by overlapping the outer circumference of the first helical layer 35. The second helical layer 36 is formed by spirally winding the second strand 36a along a second direction around the axis A of the tube 31. In this case, the second direction is the direction that intersects the first direction.

[0038] More specifically, the second helical layer 36 is formed by winding a second group of wires 36ag, which consists of a plurality (for example, three) of second wires 36a, in a helical shape.

[0039] As shown in Figure 2, the second helical layer 36 has a third portion A3 in which the second group of wires 36ag is wound at a third pitch P3, and a fourth portion A4 in which the second group of wires 36ag is wound at a fourth pitch P4 which is denser than the third pitch P3. These third portion A3 and fourth portion A4 are arranged alternately along the direction of axis A. Here, the third pitch P3 is defined in the third portion A3 in which the second group of wires 36ag is wound helically for multiple periods, based on the relationship between the helical period of interest (the earlier period) and other helical periods adjacent to the base end of the helical period of interest (the later period). That is, the third pitch P3 is defined by the distance between the second wire 36a located at the base end of the second group of wires 36ag in the earlier period and the second wire 36a located at the tip of the second group of wires 36ag in the later period. Similarly, the fourth pitch P4 is defined in the fourth section A4, where the second group of wires 36ag is wound spirally for multiple periods, based on the relationship between the spiral period of interest (the earlier period) and other spiral periods adjacent to the base end of the spiral period of interest (the later period). That is, the fourth pitch P4 is defined by the distance between the second wire 36a located at the base end of the second group of wires 36ag in the earlier period and the second wire 36a located at the tip of the second group of wires 36ag in the later period.

[0040] In this embodiment, the third pitch P3 and the fourth pitch P4 are set to be different from the spacing between the respective first element wires 35a constituting the second element wire group 36ag. More specifically, the third pitch P3 and the fourth pitch P4 are set to be larger than the spacing between the respective second element wires 36a constituting the second element wire group 36ag. Note that when the second helical layer 36 is formed of a single second element wire 36a, the helical pitch of the second element wire 36a is the third pitch P3 and the fourth pitch P4.

[0041] The third portion A3 is formed at a position corresponding to the second portion A2, and the fourth portion A4 is formed at a position corresponding to the first portion A1. In the first portion A1, which is the portion where the pitch of the first helical layer 35 is sparse, the second element wire 36a can be generally spirally wound without being interfered by the first element wires 35a. Accordingly, as shown in, for example, FIG. 2, the fourth portion A4 of the second helical layer 36 is arranged substantially in the same row as the second portion A2 of the first helical layer 35 in the axis A direction. That is, the inner diameter of the fourth portion A4 of the second helical layer 36 generally substantially matches the inner diameter of the first helical layer 35.

[0042] Here, the second helical layer 36 is preferably arranged such that the sign of the helical phase of the second helical layer 36 is different from the sign of the helical phase of the first helical layer 35. In particular, the second helical layer 36 is preferably arranged such that the phase of the helix formed in the second helical layer 36 is opposite to the phase of the helix formed in the first helical layer 35.

[0043] It should be noted that the second helical layer 36 is not limited to one formed by three second element wires 36a. The second helical layer 36 can be formed using any number of one or more second element wires 36a.

[0044] The first resin layer 32 is formed using, for example, a flexible resin material. The resin material is preferably a thermoplastic resin, and is preferably a urethane-based resin, polypropylene synthetic resin, polyethylene-based resin, polyamide resin, ethyl vinyl alcohol-based resin, styrene block copolymer, or the like. The inner diameter of the first resin layer 32 is set to be smaller than the inner diameter of the first helical layer 35.

[0045] Further, the outer diameter of the first resin layer 32 is set to be larger than the inner diameter of the first helical layer 35 and smaller than the outer diameter of the first helical layer 35. Accordingly, the entire inner circumference of the first helical layer 35 is in contact with the peripheral surface (outer circumferential surface) of the first resin layer 32. Further, the inner circumference of the second helical layer 36 is in contact with the peripheral surface (outer circumferential surface) of the first resin layer 32 in the fourth portion A4.

[0046] More specifically, the first resin layer 32 is filled between the respective first element wires 35a and between the pitches of the first element wire group 35ag on the inner circumference side of the first helical layer 35. Further, the first resin layer 32 is filled between the respective second element wires 36a and between the pitches of the second element wire group 36ag on the inner circumference side of the fourth portion A4 of the second helical layer 36. That is, the entire region of the first helical layer 35 and the fourth portion A4 of the second helical layer 36 are directly bonded (adhered) to the first resin layer 32. Accordingly, as shown in FIGS. 4 and 5, the first resin layer 32 limits displacement of the fourth portion A4 of the first helical layer 35 and the second helical group 36 in the axis A direction and the radial direction, and maintains the helical shape of the first element wires 35a and the respective second element wires 36a.

[0047] Next, a method for manufacturing the medical tube 30 will be described according to the flowchart in FIG. 6.

[0048] In the manufacture of this medical tube 30, in step S10, a step of applying a first resin material 32a, which is the material of the first resin layer 32, to a molding core material 40 is performed. That is, for example, as shown in FIG. 7, the molten first resin material 32a is applied to the outer circumference of the core material 40.

[0049] As the first resin material 32a, a material having predetermined elasticity even when cured is selected. In FIGS. 7 to 11, the molten first resin material 32a is indicated with dots.

[0050] In the subsequent step S20, a first helical layer 35 is formed on the outer circumference of the coated first resin material 32a. That is, as shown in Figures 8 and 9, the first group of wires 35ag is wound spirally around the outer circumference of the first resin material 32a. More specifically, the first group of wires 35ag is wound spirally around the outer circumference of the first resin material 32a in a first direction (for example, clockwise) around axis A. At this time, the first helical layer 35 is alternately formed with first parts A1 and second parts A2 having different pitches. In addition, a portion of each wound first wire 35a near the inner circumference is embedded in the first resin material 32a.

[0051] In the following step S30, the process of forming the second helical layer 36 is carried out. That is, as shown in Figures 10 and 11, the second group of wires 36ag is wound spirally around the outer circumference of the first helical layer 35. More specifically, the second group of wires 36ag is wound spirally around the outer circumference of the first helical layer 35 in a second direction (for example, a counterclockwise direction) that intersects the first direction around axis A. At this time, the second helical layer 36 is alternately formed with a third portion A3 and a fourth portion A4 with different pitches. In addition, a portion of the inner circumference of each wound second wire 36a is embedded in the first resin material 32a in the fourth portion A4 of the second helical layer 36.

[0052] In the subsequent step S40, a curing process is performed on the first resin material 32a. This curing process is achieved, for example, by cooling the molten first resin material 32a. This forms a medical tube 30 comprising a tubular body 31 and a first resin layer 32.

[0053] In the following step S50, the medical tube 30 is removed from the core material 40.

[0054] In this embodiment, the medical tube 30 includes a first resin layer 32 extending from the tip to the base along the axis A, a first helical layer 35 arranged on the outer circumference of the first resin layer and formed by spirally winding a first wire 35a along a first direction, and a second helical layer 36 arranged on the outer circumference of the first helical layer and formed by spirally winding a second wire 36a along a second direction intersecting the first direction. The first helical layer 35 also includes a first portion A1 in which the first wire 35a is wound at a first pitch P1, and a first portion A2 in which the first wire 35a is wound at a second pitch P2 which is denser than the first pitch P1. Furthermore, the second helical layer 36 includes a third portion A3 in which the second strand 36a is wound at a third pitch P3, and a fourth portion A4 in which the second strand 36a is wound at a fourth pitch P4 which is denser than the third pitch P3. The third portion A3 is positioned on the outer circumference of the second portion A2, and the fourth portion A4 is positioned on the outer circumference of the first portion A1, with the second portion A2 and the fourth portion A4 each in contact with the outer surface of the first resin layer 32. As a result, the medical tube 30 can be made highly productive and maintain appropriate flexibility.

[0055] In other words, the tubular body 31 of the medical tube 30 is composed of a two-layer structure: a first helical layer 35 formed by spirally winding a first strand 35a along a first direction, and a second helical layer 36 formed by spirally winding a second strand 36a along a second direction on the outer circumference of the first helical layer 35. Therefore, the tubular body 31 can be formed with excellent productivity without weaving the first strand 35a and the second strand 36a together.

[0056] Furthermore, in the medical tube 30, the fourth portion A4, which is the part of the second helical layer 36 with a dense pitch, is positioned on the outer circumference of the first portion A1, which is the part of the first helical layer 35 with a sparse pitch. This allows both the second portion A2 and the fourth portion A4, which greatly contribute to the flexibility of the medical tube 30, to be in contact with the first resin layer 32. This suppresses displacement of the second portion A2 and the fourth portion A4 in the axial A direction, and maintains the appropriate flexibility of the medical tube 30. In particular, in this embodiment, a part of the second portion A2 of the first helical layer 35 near the inner circumference and a part of the fourth portion A4 of the second helical layer 36 near the inner circumference are bonded to the first resin layer 32 by being embedded in the first resin layer 32. As a result, displacement of the second portion A2 of the first helical layer 35 and the fourth portion A4 of the second helical layer 36 is suppressed not only in the axial A direction but also in the radial direction. Therefore, the appropriate flexibility of the medical tube 30 can be more effectively maintained.

[0057] (Modified Version) Next, a modified version of this embodiment will be described with reference to Figures 12 to 17. As shown in Figures 12 to 15, in this modified version, the medical tube 30 has a second resin layer 37 on the outer layer of the second helical layer 36.

[0058] In this modified example, the second resin material 37a forming the second resin layer 37 is a different resin material from the first resin material 32a forming the first resin layer 32. Here, the second resin material 37a is selected to be a material that has a predetermined elasticity even when cured. Note that the second resin material 37a may be the same resin material as the first resin material 32a.

[0059] Such medical tubes 30 are manufactured, for example, according to the flowchart shown in Figure 16.

[0060] In the manufacture of this medical tube 30, the processes described above from step S10 to step S40 are carried out first.

[0061] In the subsequent step S50, the second resin material 37a is applied to the second helical layer 36. That is, as shown in Figure 17, the molten second resin material 37a is applied to the outer circumference of the second helical layer 36. In Figure 17, the molten second resin material 37a is indicated by dots.

[0062] In this case, the second helical layer 36 is coated with an amount of second resin material 37a that is greater than the total volume of the gaps in the first helical layer 35 and the second helical layer 36 that are exposed from the first resin layer 32. That is, the second helical layer 36 is coated with an amount of second resin material 37a that is greater than the total volume of the gaps formed between the first strands 35a exposed from the first resin layer 32, the gaps formed between the pitches of the first strands 35ag exposed from the first resin layer 32, the gaps formed between the second strands 36a exposed from the first resin layer 32, and the gaps formed between the pitches of the second strands 36ag exposed from the first resin layer 32.

[0063] In the following step S60, a penetration process is performed for the second resin material 37a applied to the second helical layer 36. In this penetration process, for example, the core material 40 after the second resin material 37a has been applied is brought into a pressure chamber. Then, by increasing the internal pressure of the pressure chamber, a predetermined pressure is applied to the second resin material 37a. As a result, the second resin material 37a penetrates between each first strand 35a, between the pitches of the first strand group 35ag, between each second strand 36a, and between the pitches of the second strand group 36ag. Furthermore, the second resin material 37a reaches the outer surface of the first resin layer 32. In this case, since the amount of the second resin material 37a is greater than the total volume of the gap between the first helical layer 35 and the second helical layer 36, the first helical layer 35 and the second helical layer 36 are embedded inside the second resin material 37a.

[0064] In the subsequent step S70, a curing process is performed on the second resin material 37a. This curing process is achieved, for example, by cooling the molten second resin material 37a. This forms a medical tube 30 comprising the tubular body 31, the first resin layer 32, and the second resin layer 37. The cured second resin layer 37 adheres closely to the first resin layer 32 and seals the first helical layer 35 and the second helical layer 36.

[0065] In the following step S80, the medical tube 30 is removed from the core material 40.

[0066] With this modified configuration, by providing the second resin layer 37, it is possible to more accurately suppress significant fluctuations in the pitch P2 of the second helical layer 36 in the axial A direction, and displacement of the second helical layer 36 in the outer diameter direction.

[0067] Furthermore, when the medical tube 30 is used in the flexible tube portion 8 of the endoscope 1, the second resin layer 37 can function as the outer sheath of the flexible tube portion 8.

[0068] Here, for example, as shown in Figures 18 and 19, in this modified example, it is also possible to omit the first resin layer 32 and construct a medical tube 30 in which the second portion A2 of the first helical layer 35 and the fourth portion A4 of the second helical layer 36 are in contact with the circumferential surface (inner circumferential surface) of the second resin layer 37.

[0069] It should be noted that the present invention is not limited to the embodiments and variations described above, and various modifications and changes are possible, all of which fall within the technical scope of the present invention.

[0070] For example, the configurations of the above-described embodiments and their respective modifications may be combined as appropriate. Furthermore, the application of the medical tube 30 is not limited to single-use endoscopes, but can also be applied to reusable endoscopes. Moreover, the application of the medical tube 30 is not limited to endoscopes, but can also be applied as a stent or the like.

[0071] [Note 1] A method for manufacturing a medical tube, comprising: supplying molten resin to a core material for molding; winding a first wire along a first direction on the outer surface of the molten resin to form a first helical layer; and curing the molten resin to form a first cylindrical layer.

[0072] [Note 2] A method for manufacturing a medical tube according to Note 1, comprising the step of cooling the molten resin in the step of forming the first cylindrical layer.

[0073] [Note 3] The method for manufacturing a medical tube according to Note 1, wherein at least a portion of the step of forming the first cylindrical layer is performed simultaneously with the step of forming the first helical layer.

[0074] 1… Endoscope 2… Insertion section 3… Control section 4… Universal cable 5… Connector 6… Tip section 7… Bending section 8… Flexible tube section 10… Imaging unit 11… Signal cable 12… Traction wire 13… Light guide 14… Treatment instrument channel 15… Outer sheath 20… Anti-bend section 21… Gripping section 22… Control section body 23… Treatment instrument insertion section 23a… Treatment instrument insertion port 25… Bending lever 26… Operation button group 30… Medical tube 31… Tube body 31… Tube body 32… First resin layer 32a… First resin material 35… First helical layer 35a… First strand 35ag… First strand group 36… Second helical layer 36a… Second strand 36ag… Second wire group 37 … Second resin layer 37a … Second resin material 40 … Core material A … Axis

Claims

1. A medical tube comprising: a first cylindrical layer extending from the tip to the base along an axis; a first helical layer in which first strands are formed spirally along a first direction; and a second helical layer disposed on the outer circumference of the first helical layer and in which second strands are formed spirally along a second direction intersecting the first direction, wherein the first helical layer comprises a first portion in which the first strands are wound at a first pitch and a second portion in which the first strands are wound at a second pitch that is denser than the first pitch; the second helical layer comprises a third portion in which the second strands are wound at a third pitch and a fourth portion in which the second strands are wound at a fourth pitch that is denser than the third pitch, wherein the third portion is disposed on the outer circumference of the second portion and the fourth portion is disposed on the outer circumference of the first portion, and the second portion and the fourth portion are each in contact with the circumferential surface of the first cylindrical layer.

2. The medical tube according to claim 1, characterized in that the second and fourth parts are attached to the first cylindrical layer.

3. The medical tube according to claim 2, characterized in that the second and fourth parts are each bonded to the first cylindrical layer.

4. The medical tube according to claim 3, characterized in that the second and fourth parts are directly bonded to the first tubular layer.

5. The medical tube according to claim 1, further comprising a second cylindrical layer provided on the opposite side of the first cylindrical layer, with the first helical layer and the second helical layer in between.

6. The medical tube according to claim 1, characterized in that the sign of the phase of the helix of the first helical layer is different from the sign of the phase of the helix of the second helical layer.

7. The medical tube according to claim 1, wherein the first helical layer is formed by a first group of wires including two or more first wires arranged along the axis, the first pitch and the second pitch are the distance between the first wire located at the base end of the first group of wires in an earlier period and the first wire located at the tip of the first group of wires in a later period, the second helical layer is formed by a second group of wires including two or more second wires arranged along the axis, the third pitch and the fourth pitch are the distance between the second wire located at the base end of the second group of wires in an earlier period and the second wire located at the tip of the second group of wires in a later period.

8. The medical tube according to claim 1, characterized in that the angle between the first direction and the axis in the first portion is greater than the angle between the first direction and the axis in the second portion, and the angle between the second direction and the axis in the third portion is greater than the angle between the second direction and the axis in the fourth portion.

9. The medical tube according to claim 1, characterized in that the first cylindrical layer is located inside the first helical layer.

10. The medical tube according to claim 1, characterized in that the first cylindrical layer is located outside the second helical layer.

11. The medical tube according to claim 1, characterized in that the first cylindrical layer is formed of resin.

12. The medical tube according to claim 11, characterized in that the resin is a thermoplastic resin.

13. The medical tube according to claim 1, characterized in that at least one of the first strand and the second strand is made of metal.

14. The medical tube according to claim 13, characterized in that the metal is stainless steel.

15. The medical tube according to claim 11, characterized in that at least one of the first strand and the second strand is made of metal.

16. An endoscope comprising: a first cylindrical layer extending from the tip to the base along an axis; a first helical layer in which first strands are formed spirally along a first direction; and a second helical layer arranged on the outer circumference of the first helical layer and in which second strands are formed spirally along a second direction intersecting the first direction, wherein the first helical layer comprises a first portion in which the first strands are wound at a first pitch and a second portion in which the first strands are wound at a second pitch that is denser than the first pitch; the second helical layer comprises a third portion in which the second strands are wound at a third pitch and a fourth portion in which the second strands are wound at a fourth pitch that is denser than the third pitch, wherein the third portion is arranged on the outer circumference of the second portion and the fourth portion is arranged on the outer circumference of the first portion, and the second portion and the fourth portion each include a medical tube in the insertion portion that is in contact with the circumferential surface of the first cylindrical layer.

17. A method for manufacturing a medical tube, comprising: forming a first portion by spirally winding a first wire at a first pitch along a first direction around an axis; forming a second portion by spirally winding the first wire at a second pitch that is denser than the first pitch along the first direction; forming a third portion on the outer circumference of the second portion by spirally winding a second wire at a third pitch along a second direction intersecting the first direction; forming a fourth portion on the outer circumference of the first portion by spirally winding the second wire at a fourth pitch that is denser than the third pitch along the second direction; and forming a first cylindrical layer having a circumferential surface that contacts the second portion and the fourth portion.

18. The method for manufacturing a medical tube according to claim 17, characterized in that the outer circumferential surface of the first cylindrical layer is in contact with the second and fourth portions.

19. The method for manufacturing a medical tube according to claim 17, characterized in that the inner circumferential surface of the first cylindrical layer is in contact with the second portion and the fourth portion.

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