JP6869350B2 - Flexible tubes for endoscopes and endoscopes - Google Patents

Description

The present invention relates to a flexible tube for an endoscope and an endoscope.

For example, in Japanese Patent Application Laid-Open No. 2013-097327, a spiral tube in the inner layer of a flexible tube for an endoscope is provided with a close-contact winding portion to which initial tension is applied and a loosely wound portion arranged at one end of the close-contact winding portion. It is disclosed that it has. When this flexible tube is bent, the sparsely wound portion of the spiral tube contracts along the longitudinal axis (central axis) of the flexible tube, so that the total length along the longitudinal axis of the flexible tube is changed. Can be bent without. Since the close contact winding portion to which the initial tension is applied is formed to an appropriate length, the flexible tube has enhanced elasticity that makes it easy to return the bent state of the flexible tube to the linear state.

For example, the spiral tube of a flexible tube disclosed in Japanese Patent Application Laid-Open No. 2013-097327 has a close-contact winding portion and a loosely wound portion in both the case where the linear state is set to the bent state and the case where the bent state is set to the linear state. Is moved along the longitudinal axis. For example, a blade (reticulated tube) is arranged on the outside of the spiral tube of the flexible tube, and the outside of the blade is coated with a resin material as an exodermis. Since the blade is woven with a thin wire, its rigidity in the radial direction is smaller than that of the spiral tube, and the outer peripheral surface is easily crushed inward in the radial direction in the bent state and is easily flattened. Therefore, when the tightly wound portion and the loosely wound portion are moved along the longitudinal axis, it is required to suppress the interference between the outer peripheral surface of the spiral tube and the outer layer thereof.

An object of the present invention is to provide a flexible tube for an endoscope and an endoscope having good elasticity while suppressing interference between the spiral tube and its outer layer.

In the flexible tube for an endoscope according to one aspect of the present invention, a plate-shaped first wire is spirally wound, and adjacent portions of the first wire are in close contact with each other. The contact portion is provided on the outer peripheral side of the first spiral tube formed over the entire length along the longitudinal axis and the first spiral tube, and is bent with respect to the longitudinal axis together with the first spiral tube. , The flexible outer skin is provided between the outer skin and the first spiral tube, and the second wire is spirally wound, and the length is longer than that of the first wire. It has a second spiral tube having a narrow width along the axis and a larger number of turns per unit length than the first spiral tube on the outside of the first contact portion. When the second spiral tube is linearized along the longitudinal axis together with the exodermis, at least a part of the second strand is always in contact with the outer peripheral surface of the first spiral tube.

FIG. 1 is a schematic view showing an endoscope according to the first to third embodiments. FIG. 2A is a schematic cross-sectional view taken along the longitudinal axis of the flexible tube of the insertion portion of the endoscope according to the first embodiment. FIG. 2B is a schematic view showing the structure of the flexible tube of the insertion portion of the endoscope according to the first embodiment. FIG. 3A is a schematic view showing a part of an appropriate coil. FIG. 3B is a schematic view showing the relationship between the coil length, the twist angle, and the diameter in FIG. 3A. FIG. 4 is a schematic diagram showing a comparison of changes in the outer diameter according to the pitch of the spiral tubes when spiral tubes having different pitches (widths along the longitudinal axis) are stretched to the same length along the longitudinal axis. It is a figure. FIG. 5 is a schematic view showing a bent state of the flexible tube shown in FIG. 2A of the insertion portion of the endoscope according to the first embodiment. FIG. 6 is a schematic cross section of the flexible tube according to the first modification of the first embodiment, showing a flexible tube having no contact portion on the second spiral tube outside the first spiral tube. It is a figure. FIG. 7A shows the flexible tube when the winding direction of the first spiral tube of the flexible tube according to the first modification of the first embodiment and the winding direction of the second spiral tube are opposite to each other. It is a schematic diagram which shows the state of the 1st spiral tube and the 2nd spiral tube at the time of starting bending from the straight state. FIG. 7B shows the flexible tube when the winding direction of the first spiral tube of the flexible tube according to the first modification of the first embodiment and the winding direction of the second spiral tube are the same direction. It is a schematic diagram which shows the state of the 1st spiral tube and the 2nd spiral tube at the time of starting bending from the straight state. FIG. 8A is a schematic cross-sectional view showing a second spiral tube of the flexible tube according to the second modification of the first embodiment, which has a close contact portion having a shape different from that of the example shown in FIG. 2A. FIG. 8B is a schematic cross-sectional view showing a second spiral tube of the flexible tube according to the second modification of the first embodiment, which has a close contact portion having a shape different from that of the examples shown in FIGS. 2A and 8A. is there. FIG. 8C is a schematic view showing a second spiral tube of the flexible tube according to the second modification of the first embodiment, which has a close contact portion having a shape different from the examples shown in FIGS. 2A, 8A and 8B. It is a sectional view. FIG. 9 is a schematic view of a flexible tube according to a third modification of the first embodiment, wherein the first spiral tube has a loosely wound portion in the vicinity of the base end portion of the first spiral tube. It is a cross-sectional view. FIG. 10 is a schematic view of the flexible tube according to the fourth modification of the first embodiment, showing the flexible tube in a state where the second spiral tube is separated from the inner peripheral surface of the exodermis. It is a sectional view. FIG. 11 shows a flexible tube according to a fifth modification of the first embodiment, in which a second spiral tube is embedded between the inner peripheral surface and the outer peripheral surface of the outer skin. It is a schematic cross-sectional view which shows. FIG. 12 is a schematic cross-sectional view of the flexible tube of the insertion portion of the endoscope according to the second embodiment along the longitudinal axis. FIG. 13A is a schematic view showing a left-handed wire spiral tube forming a part of the flexible tube. FIG. 13B shows a left-handed wire spiral tube that constitutes a part of the flexible tube, and from the state shown in FIG. 13A with one end side (the left end portion in FIG. 13B) fixed. A state in which the other end side (the right end portion in FIG. 13B) of the spiral tube is rotated in the direction of the arrow α with respect to the longitudinal axis (central axis) and the other end side is reduced in diameter with respect to the one end side is shown. It is a schematic diagram. FIG. 13C shows a left-handed wire spiral tube forming a part of the flexible tube, and from the state shown in FIG. 13A with one end side (the left end portion in FIG. 13C) of the spiral tube fixed. The other end side (the right end portion in FIG. 13C) of the spiral tube is rotated in the direction of the arrow β with respect to the longitudinal axis (central axis), and the diameter of the other end side is enlarged with respect to the one end side. It is a schematic diagram. In FIG. 14A, when the flexible tube according to the second embodiment is rotated in the direction of the arrow α with respect to the longitudinal axis, the inner layer and the outer layer of the first spiral tube and the second spiral tube are in the radial direction. It is a schematic cross-sectional view which shows typically the state of reducing / expanding the diameter. FIG. 14B shows the first spiral tube, the inner layer and the outer layer of the second spiral tube in the radial direction when the flexible tube according to the second embodiment is rotated in the direction of the arrow β with respect to the longitudinal axis. It is a schematic cross-sectional view which shows typically the state of reducing / expanding the diameter. FIG. 15 is a schematic cross-sectional view taken along the longitudinal axis of the flexible tube of the insertion portion of the endoscope according to the third embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First Embodiment)
The first embodiment will be described with reference to FIGS. 1 to 5.

As shown in FIG. 1, the endoscope 10 has an elongated insertion portion 12 that can be inserted into a hole such as an appropriate body cavity such as the large intestine or the esophagus. The insertion portion 12 defines the longitudinal axis L by its tip end and base end. In this embodiment, the endoscope 10 has an operation unit 14 held at the base end portion of the insertion unit 12 by a user (operator) to perform various operations. The operation unit 14 is gripped by the user with the operation unit main body 16 on which the UD knob 16a and the RL knob 16b are arranged, and the base end portion of the insertion portion 12 (the base of the flexible tube 26 described later) via the break stopper 18a. It has a grip portion 18 disposed at the end portion).

The insertion portion 12 has a tip portion 22, a curved portion 24, and a flexible tube (flexible tube for an endoscope) 26 from the tip end side to the proximal end side along the longitudinal axis L. The tip portion 22 is located at the most tip of the insertion portion 12, and is formed of, for example, a hard material in which the tip of the illumination optical system, the tip of the observation optical system, the tip of the channel (both not shown) and the like are arranged. The curved portion 24 can be bent upward and downward by operating the UD knob 16a of the operating portion 14. Further, the curved portion 24 can be curved in the right direction and the left direction by operating the RL knob 16b of the operating portion 14. The upward and downward directions of the curved portion 24 are substantially parallel to the vertical direction of the image obtained by, for example, the above-mentioned observation optical system. Similarly, the right and left directions of the curved portion 24 are substantially parallel to, for example, the horizontal direction of the above-mentioned image.
Although the insertion portion 12 describes an example in which the curved portion 24 is actively curved, the insertion portion 12 may have a structure in which the curved portion is passively curved by an external force. The insertion portion 12 may have a structure that is actively curved and a structure that is passively curved as the curved portion 24 adjacent to each other along the longitudinal axis L.

The flexible tube 26 has flexibility and is passively bent by an external force toward the longitudinal axis L. As shown in FIG. 2A, the flexible pipe (serpentine pipe portion) 26 has a hollow shape. The flexible tube 26 is formed to have a longer overall length along the longitudinal axis L than the tip portion 22 and the curved portion 24 of the insertion portion 12. The flexible pipe 26 is provided between the curved portion 24 and the grip portion 18 of the operating portion 14. The flexible tube 26 has a straight straight state (see FIG. 2A) and a bent state bent with respect to the straight state (see FIG. 5), that is, a state bent with respect to a longitudinal axis L extending linearly. It can be elastically deformed between.

The flexible pipe 26 has a first spiral pipe 32 and an outer layer portion 34 in this order from the inner side to the outer side in the radial direction. The first spiral tube 32 is interpolated in the outer layer portion 34. A common central axis C parallel to the longitudinal axis L is defined in the first spiral tube 32 and the outer layer portion 34. In the flexible pipe 26 according to the present embodiment, the central axis C and the longitudinal axis L coincide with each other. The outer layer portion 34 has appropriate flexibility. The outer layer portion 34, together with the first spiral tube 32, is elastically deformable between a linear state (see FIG. 2A) and a bent state (see FIG. 5) in which the longitudinal axis L (central axis C) is bent.

The outer layer portion 34 has, for example, a coil-shaped second spiral tube 42 and an outer skin 44 made of a resin material coated on the outer peripheral side thereof. As an example, it is preferable that the second spiral tube 42 and the outer skin 44 are integrated, such that at least a part of the second spiral tube 42 is embedded in the outer skin 44. The second spiral tube 42 is provided between the outer peripheral surface of the outer skin 44 and the outer peripheral surface of the first spiral tube 32. The second spiral tube 42 is not exposed on the outer peripheral surface of the flexible tube 26 when the flexible tube 26 is assembled as the endoscope 10. The inner peripheral surface of the second spiral tube 42 is preferably in contact with the outer peripheral surface of the first spiral tube 32. Therefore, the second spiral tube 42 is provided between the inner peripheral surface of the outer skin 44 and the outer peripheral surface of the first spiral tube 32.

The first spiral pipe 32 and the outer layer portion 34 are fixed at the tip and base ends of the flexible pipe 26, that is, both ends separated along the longitudinal axis L, respectively, in a state of substantially straight line and natural length.

Bases 26a and 26b are connected to both ends of the flexible pipe 26. One mouthpiece (tip end side mouthpiece) 26a is connected to the curved portion 24, and the other mouthpiece (base end side mouthpiece) 26b is connected to the grip portion 18 of the operation portion 14.

One mouthpiece 26a has a mouthpiece main body (inner mouthpiece) 27a and a ring-shaped member (outer mouthpiece) 27b. The inner peripheral surface of the base body 27a is connected to the tip of the first spiral tube 32 by, for example, laser welding. In addition, the inner peripheral surface of the base body 27a and the tip of the first spiral tube 32 can be connected by a general fixing method such as soldering, an adhesive, or caulking.
The tip of the second spiral tube 42 is arranged on the outer peripheral surface of the base body 27a. A ring-shaped member 27b is arranged on the outside of the tip of the second spiral tube 42. The ring-shaped member 27b crimps the tip end portion of the second spiral tube 42 with the outer peripheral surface of the base body 27a. Therefore, the tip of the second spiral tube 42 is connected to the base 26a. The base 26a and the second spiral tube 42 may be connected by an appropriate fixing method in addition to using the ring-shaped member 27b. A gap may be formed between the mouthpiece 26a and the tip of the outer skin 44. For example, a rubber tube (not shown) is coated on the outer periphery of the curved portion 24, the base 26a, and the outer skin 44.

The other base 26b has an inner base 28a and an outer base 28b. A base end portion of the first spiral tube 32 and a base end portion of the outer layer portion 34 are arranged between the outer peripheral surface of the inner mouthpiece 28a and the inner peripheral surface of the outer mouthpiece 28b. The outer mouthpiece 28b crimps the base end portion of the first spiral pipe 32 and the base end portion of the outer layer portion 34 with the outer peripheral surface of the inner mouthpiece 28a. Therefore, the base end portion of the first spiral tube 32 and the base end portion of the outer layer portion 34 are connected to the base 26b. The base end portion of the first spiral tube 32 and the base end portion of the outer layer portion 34 and the base 26b may be connected by other appropriate fixing methods.

The first spiral tube 32 and the outer layer portion 34 are fixed only at both ends by the caps 26a and 26b. The first spiral tube 32 and the outer layer portion 34 are formed with the first spiral tube 32 and the outer layer portion 34 when the flexible tube 26 is deformed from a linear state (see FIG. 2A) to a bent state (see FIG. 5). Suppress the difference in elongation between. The caps 26a and 26b have the first spiral tube 32, the second spiral tube 42 and the outer skin 44 when the flexible tube 26 is deformed from the linear state (see FIG. 2A) to the bent state (see FIG. 5). Stretch by the same length. Further, the caps 26a and 26b contract the first spiral tube 32, the second spiral tube 42 and the outer skin 44 by the same length when the flexible tube 26 is deformed from the bent state to the linear state. That is, it is prevented that the expansion and contraction amounts of the first spiral tube 32, the second spiral tube 42, and the outer skin 44 are different from each other. As a result, the flexible tube 26 has the first spiral tube 32, the second spiral tube 42, and the outer skin 44 on the longitudinal axis L (central axis C) regardless of whether the flexible tube 26 is in a straight state or a bent state. The lengths along are about the same. That is, the total lengths of the first spiral tube 32 and the outer layer portion 34 along the longitudinal axis L are substantially the same.

The first spiral tube 32 is formed by spirally winding a first wire 32a. The first wire 32a is formed in a plate shape formed of, for example, a metal material such as a stainless steel material, for example, a flat plate shape. The plate width of the first wire 32a is preferably constant from one end to the other end, and is not limited because it differs depending on the model (outer diameter and bendability) of the endoscope 10 according to the insertion target. Absent. The plate width of the first wire 32a is, for example, about 2 mm to 4 mm. The plate thickness of the first wire 32a is preferably constant from one end to the other end, and is not limited thereto either. The plate thickness of the first wire 32a is, for example, about 0.3 mm to 0.5 mm.

The first spiral tube 32 has a close contact portion (first close contact portion) 33 in which adjacent portions (edges) 32b and 32c of the first strand 32a are in close contact with each other along the longitudinal axis L. Therefore, in the first spiral tube 32, a close contact portion 33 is formed between the adjacent portions 32b and 32c of the first wire 32a. In particular, in the present embodiment, in the first spiral tube 32, one close contact portion 33 is continuously formed over the entire length between one end and the other end. The close contact portion 33 is wound in a state in which adjacent portions 32b and 32c of the first wire 32a have an initial tension (preload) in a direction of compressing each other along the longitudinal axis L and are in close contact with each other. The initial tension is a state in which adjacent portions 32b and 32c are in close contact with each other against a predetermined or less load applied from the outside of the first spiral tube 32 along the longitudinal axis L or toward the longitudinal axis L. Is the power to maintain. Therefore, the adjacent portions 32b and 32c of the first wire 32a are pressed against each other along the longitudinal axis L. It is preferable that the inner diameter and the outer diameter of the first spiral tube 32 are substantially constant. The inner diameter of the first spiral tube 32 at this time is, for example, about 9 mm to 12 mm. Of the adjacent portions 32b and 32c of the first strand 32a, one is the distal end side portion 32b directed toward the distal end side and the other is the proximal end side portion 32c directed toward the proximal end side.

The second spiral tube (coil) 42 of the outer layer portion 34 is formed by spirally winding a second wire 42a formed of, for example, a metal material such as a stainless steel material. The second wire 42a of the second spiral pipe 42 has a smaller dimension (width) in the direction along the longitudinal axis L than the first wire 32a of the first spiral pipe 32. The cross-sectional shape of the second strand 42a of the second spiral tube 42 is not limited. The cross-sectional shape of the second strand 42a is, for example, circular. The second wire 42a preferably has a diameter of 2 to 5 times that of the wire used for the blade (reticulated tube) of the flexible tube of a general endoscope, for example. The diameter of the second strand 42a is not limited. The diameter of the second wire 42a is, for example, about 0.4 mm to 0.5 mm. Then, in the present embodiment, the second spiral tube 42 is also wound in a state of being in close contact with the initial tension, similarly to the first spiral tube 32. That is, the second spiral tube 42 has a close contact portion (second close contact) in which the second strand 42a is spirally wound and the adjacent portions (edges) 42b and 42c are in close contact with each other along the longitudinal axis L. Part) 43. Therefore, in the second spiral tube 42, a close contact portion 43 is formed between the adjacent portions 42b and 42c of the second wire 42a, respectively. In particular, in the present embodiment, in the second spiral tube 42, one close contact portion 43 is continuously formed over the entire length between one end and the other end. The close contact portion 43 is wound in a state in which adjacent portions 42b and 42c of the second wire 42a have an initial tension (preload) in a direction of compressing each other along the longitudinal axis L and are in close contact with each other. Therefore, the adjacent portions 42b and 42c of the second strand 42a are pressed against each other along the longitudinal axis L. The inner diameter of the second spiral tube 42 at this time is not limited because it differs depending on the 10 types of endoscopes (diameter and bendability) according to the insertion target. The inner and outer diameters of the second spiral tube 42 are substantially constant. The inner diameter of the second spiral tube 42 is, for example, about 9 mm to 12 mm. Of the adjacent portions 42b and 42c of the second wire 42a, one is the distal end side portion 42b directed toward the distal end side, and the other is the proximal end side portion 42c directed toward the proximal end side.

In the second spiral tube 42, the second strand 42a, which is narrower along the longitudinal axis L than the first strand 32a, has a unit length outside the contact portion 33 and longer than the first spiral tube 32. It is formed by being spirally wound so that the number of turns per winding is large. Therefore, the pitch P2 of the second spiral tube 42 is smaller than the pitch P1 of the first spiral tube 32. As shown in FIG. 2B, the winding direction of the second spiral tube 42 is preferably opposite to the winding direction of the first spiral tube 32. Over the entire length of the flexible tube 26, for example, the winding direction α of the first spiral tube 32 is clockwise (clockwise starting from the winding start (end)), and the winding direction β of the second spiral tube 42 is. Left-handed (counterclockwise starting from the beginning (end) of winding).

Then, in a linear state of the first spiral tube 32 and the second spiral tube 42, there is a clearance between the outer peripheral surface of the first spiral tube 32 and the inner peripheral surface of the second spiral tube 42. It may or may not exist. If there is no clearance between the outer peripheral surface of the first spiral tube 32 and the inner peripheral surface of the second spiral tube 42, the outer diameter of the flexible tube 26 can be made smaller. Then, when there is no clearance between the outer peripheral surface of the first spiral tube 32 and the inner peripheral surface of the second spiral tube 42, the outer diameter of the first spiral tube 32 and the second spiral tube 42 The inner diameter has the same dimensions. Regardless of the presence or absence of clearance, the friction between the outer peripheral surface of the first spiral tube 32 and the inner peripheral surface of the second spiral tube 42 is preferably suppressed as low as possible.

The outer skin 44 coated on the second spiral tube 42 is made of an elastic and flexible resin material. In the exodermis 44, the longitudinal axis L (central axis C) is bent together with the first spiral tube 32 and the second spiral tube 42. The exodermis 44 according to the present embodiment is formed so as to be easily stretchable along the longitudinal axis L, and is formed to be less likely to expand and contract in the radial direction of the flexible pipe 26 orthogonal to the longitudinal axis L than in the direction along the longitudinal axis L. ing. Therefore, when the user twists the exodermis 44 around the axis of the longitudinal axis L while holding an appropriate position, the twisting force is satisfactorily transmitted from the proximal end side to the distal end side of the exodermis 44.

The wall thickness of the exodermis 44 is, for example, about 0.3 mm. The outer diameter of the outer skin 44, that is, the outer diameter of the flexible tube 26 is not limited and is appropriately set, for example, about 12 mm to 14 mm. As an example, it is preferable that the exodermis 44 having an outer diameter of about 13 mm can extend along the longitudinal axis L by about 20% of the total length of the exodermis 44.

For the outer skin 44, for example, resin is used as a material. The material of the resin of the outer skin 44 is not particularly limited. For the outer skin 44, polyurethane, polyester, polyether or the like is used as an example. The compounding ratio of these resins is changed from the tip end side to the base end side of the flexible tube 26. Therefore, the bendability / difficulty of bending the exodermis 44 changes from the tip end side to the base end side. It is preferable that the front end side of the exodermis 44 is soft and easy to bend, and the rear end side is harder and harder to bend. Of course, in the exodermis 44, the bendability / bendability between the tip and the base end does not gradually change, but even if the bendability / bendability for an appropriate length is constant. Good. If the first spiral tube 32 and the second spiral tube 42 are uniformly formed between one end and the other end, the bendability / difficulty of the flexible tube 26 is the outer skin 44. It is adjusted according to the ease of bending / difficulty of bending. Here, for the sake of simplification of the description, it is assumed that the bendability / difficulty of bending of the flexible pipe 26 is adjusted by the outer skin 44 so that it is harder to bend on the rear end side than on the front end side.

Inside the first spiral tube 32 of the flexible tube 26, various tubes used for air supply / water supply / suction / insertion of treatment tools, and built-in objects such as an imaging cable and a light guide bundle (optical fiber) (FIG. Not shown) is inserted. The tips of these built-in objects are connected to the tip 22 with appropriate play. Further, it is preferable to use a material (fluorine tube, rubber tube, etc.) that can be expanded and contracted along the longitudinal axis L for these built-in objects.

Here, with reference to FIGS. 3A and 3B, the relationship between the appropriate pitch of the coil 50 and the amount of diameter reduction when the coil 50 is extended along the longitudinal axis L will be briefly described.

Let D be the outer diameter of the coil 50 in the state before stretching (natural length state), θ be the twist angle per turn, and Lo be the length of the coil 50 per turn. It can be expressed as the outer diameter D of the coil 50 = Lo · sin θ / π. When the coil 50 extends along the longitudinal axis L, the length Lo of the coil 50 per winding does not change, and the twist angle θ becomes smaller. The smaller the angle θ is from 90 °, the greater the effect on the outer diameter D. As the pitch increases, the angle θ decreases. That is, the larger the pitch and the smaller the angle θ, the larger the change in the outer diameter D when extended.

It is assumed that the first spiral tube 32 and the second spiral tube 42 shown in FIG. 4 have an outer diameter D at their natural length before being extended. The first spiral tube 32 has a pitch P1 larger than the pitch P2 of the second spiral tube 42. The second spiral tube 42 has a pitch P2 smaller than the pitch P1 of the first spiral tube 32. It is assumed that the length L1 of the first spiral tube 32 and the second spiral tube 42 at the natural length along the longitudinal axis L before extension, for example, is extended to the length L2. The outer diameter of the first spiral tube 32 changes from D to d1 (<d2 <D), and the outer diameter of the second spiral tube 42 changes from D to d2 (<D). At this time, the amount of change (Dd1) in the diameter (outer diameter) of the first spiral tube 32 is larger than the amount of change (Dd2) in the diameter (outer diameter) of the second spiral tube 42. Therefore, the diameter reduction amount of the second spiral tube 42 is smaller than that of the first spiral tube 32 when the same amount of elongation occurs with respect to a certain state such as natural length.

(Action)
Next, the operation of the endoscope 10 according to the present embodiment will be described. Here, a case where the insertion portion 12 of the endoscope 10 is inserted into a hole such as an appropriately bent cavity, for example, into the intestinal tract will be described.

The user (operator) holds an appropriate position of the flexible tube 26 of the insertion portion 12 of the endoscope 10 with, for example, the right hand, and inserts the tip portion 22 into the intestinal tract along the longitudinal axis L of the flexible tube 26. I will put it in. At this time, the user pushes the tip portion 22 toward the back side of the intestinal tract along the longitudinal axis L, and while twisting the flexible tube 26, inserts the tip portion 22 toward the back side of the intestinal tract. I will go.

The first spiral tube 32 is wound with the adjacent portions 32b and 32c of the first wire 32a in close contact with each other with an initial tension over the entire length. Therefore, in the first spiral tube 32, the spiral contact portion 33 is continuously formed from one end to the other end of the second spiral tube 42. Further, in the present embodiment, the second spiral tube 42 is wound with the adjacent portions 42b and 42c of the second wire 42a in close contact with each other with an initial tension over the entire length. Therefore, in the second spiral tube 42, the close contact portion 43 is continuously formed from one end to the other end of the second spiral tube 42. Therefore, the flexible tube 26 can exhibit high elasticity due to the close contact portions 33 and 43 over the entire length. Here, the "elasticity" means the "easiness of return" in which the flexible tube 26 returns from the bent state to the original shape (straight line state).

The adhesion strength of the adhesion portions 33 and 43 may have an unintended appropriate variation depending on the position along the longitudinal axis L. However, the variation in the adhesion strength of the adhesion portions 33 and 43 of the first spiral tube 32 and the second spiral tube 42 is smaller than that of the adhesion strength. Therefore, in the first spiral tube 32 and the second spiral tube 42, there is no portion where the bendability / bendability changes abruptly along the longitudinal axis L. Therefore, when the insertion portion 12 is inserted into the intestinal tract such as the large intestine, the flexible tube 26 is prevented from being unintentionally and suddenly bent with respect to the insertion target.

The flexible tube 26 is deformed from a linear state (see FIG. 2A) to a bent state (see FIG. 5) by an appropriate load of an external force in the direction from the outer radial direction toward the longitudinal axis L. At this time, since the flexible pipe 26 has an appropriate length, it does not need to be bent under the influence of an external force over the entire length. The flexible tube 26 may only be bent, for example, at a position where an external force is applied and in the vicinity thereof.

As shown in FIG. 5, when the first spiral tube 32 is bent from the linear state to the bent state, the first spiral tube 32 is adjacent to the first wire 32a of the first spiral tube 32. A contact portion 33a that maintains contact between the portions 32b and 32c and a separating portion 33b that separates the portions 32b and 32c are formed. Similarly, when the second spiral tube 42 is bent from the linear state to the bent state, the second spiral tube 42 is provided with the adjacent portions 42b, 42c of the second wire 42a of the second spiral tube 42. A contact portion 43a that maintains contact between them and a separating portion 43b that separates the contact portion 43a are formed. Therefore, in the first spiral tube 32 and the second spiral tube 42, in the bent state, the inner peripheral side portions 52 of the flexible tube 26 are formed by the plurality of contact portions 33a and 43a, and the plurality of separation portions 33b. , 43b forms the outer peripheral side portion 54 of the flexible pipe 26. The inner peripheral side portion 52 and the outer peripheral side portion 54 are formed by the outer skin 44, the second spiral tube 42, and the first spiral tube 32, respectively. The outer peripheral side portion 54 is on the opposite side of the inner peripheral side portion 52 with the longitudinal axis L interposed therebetween. A bending radius R is defined for the inner peripheral side portion 52 of the flexible pipe 26 in a bent state in which the flexible pipe 26 is bent.

Here, when the first spiral tube 32 and the second spiral tube 42 change from the linear state to the bent state, the length of the inner peripheral side portion 52 of the first spiral tube 32 and the second spiral tube 42 is It does not change. Therefore, the length of the inner peripheral side portion 52 of the flexible pipe 26 is maintained between the linear state and the bent state, and is not stretched or contracted. Therefore, the inner peripheral side portion 52 of the flexible pipe 26 can be a neutral surface in which the length along the longitudinal axis L does not fluctuate or hardly fluctuates in the linear state and the bent state.
On the other hand, the length along the longitudinal axis L of the first spiral tube 32 and the outer layer portion 34 in the straight state is the length along the longitudinal axis L of the first spiral tube 32 and the outer layer portion 34 in the bent state. Is stretched. Therefore, the length along the longitudinal axis L is longer than the length of the inner peripheral side portion 52. Further, when the length of the inner peripheral side portion 52 does not change and the length along the longitudinal axis L becomes longer, the length of the outer peripheral side portion 54 on the opposite side of the inner peripheral side portion 52 across the longitudinal axis L Is longer than the length along the longitudinal axis L. Therefore, the length of the flexible pipe 26 along the longitudinal axis L and the length of the outer peripheral side portion 54 are extended with respect to the linear state in the bent state.

When the flexible tube 26 is bent by an external force and the flexible tube 26 extends along the longitudinal axis L, as shown in FIG. 4, the first spiral tube 32 and the second spiral tube 42 are in a linear state. Each is reduced in diameter. At this time, the pitch P2 of the second spiral tube 42 is made smaller than the pitch P1 of the first spiral tube 32. Therefore, the inner first spiral tube 32 of the flexible tube 26 has a larger diameter than the outer second spiral tube 42 of the flexible tube 26. Therefore, even if there is no clearance between the first spiral tube 32 and the second spiral tube 42 in the linear state, when the first spiral tube 32 is deformed into the bent state, the outer peripheral surface of the first spiral tube 32 and the second spiral can be formed. A clearance is generated between the inner peripheral surface of the pipe 42, that is, the inner peripheral surface of the outer layer portion 34. Therefore, the interference between the first spiral tube 32 and the second spiral tube 42 when going from the linear state to the bent state is suppressed. Therefore, the first spiral tube 32 and the second spiral tube 42 are bent while extending along the longitudinal axis L. That is, the flexible pipe 26 is bent while extending along the longitudinal axis L with respect to the linear state.

Then, in the linear state, the flexible tube 26 is formed between the adjacent portions 32b and 32c of the first wire 32a of the first spiral pipe 32 and the second wire 42a of the second spiral pipe 42. The adjacent portions 42b and 42c are in close contact with each other over the entire length. However, in the bent state, the flexible tube 26 can be bent to the minimum radius required for the endoscope 10 by appropriately extending the exodermis 44. As an example, when the outer diameter of the flexible pipe 26 is 10 mm and the radius R on the inner peripheral side when the flexible pipe 26 is bent is 40 mm, the length along the longitudinal axis L of the flexible pipe 26 is It extends about 12.5% of the total length of the flexible tube 26.

The second spiral tube 42 of the outer layer portion 34 is not woven, only the second strand 42a is formed in a spiral shape. Therefore, the second wire 42a of the second spiral tube 42 does not undulate like a blade. The second wire 42a of the second spiral tube 42 has a larger diameter and higher rigidity than the wire forming the blade, even if it is made of the same material. Therefore, the second spiral tube 42 has sufficient rigidity in the radial direction when the flexible tube 26 is bent, and can withstand a force that tends to collapse in the radial direction. Further, since the outer skin 44 of the outer layer portion 34 covers the second spiral tube 42, it moves in conjunction with the movement of the second spiral tube 42. Therefore, the outer layer portion 34 is difficult to flatten when bent. Similarly, the first spiral tube 32 has sufficient rigidity in the radial direction when the flexible tube 26 is bent, and can withstand a force that tends to collapse in the radial direction. Therefore, the first spiral tube 32 is difficult to flatten when bent. Therefore, the first spiral tube 32 and the outer layer portion 34 are unlikely to interfere with each other, and the flexible tube 26 can be smoothly bent.

The close contact portions 33 and 43 are continuous from one end to the other end of the flexible pipe 26. Then, the exodermis 44 also extends along the longitudinal axis L in conjunction with the elongation along the longitudinal axis L of the first spiral tube 32 and the second spiral tube 42. Therefore, even if the flexible tube 26 is bent, the relative movement of the first spiral tube 32, the second spiral tube 42, and the outer skin 44 along the longitudinal axis L inside the outer skin 44 is suppressed. There is. That is, the relative movement amount of the first spiral tube 32, the second spiral tube 42, and the exodermis 44 is small. Here, when the second spiral tube 42 is in a straight line state along the longitudinal axis L and in a bent state, a part of the second wire 42a is on the outer peripheral surface of the first spiral tube 32. Always in contact. In this way, even if there is no clearance between the first spiral tube 32 and the outer layer portion 34, the interference between the first spiral tube 32 and the outer layer portion 34 is suppressed, and the flexible tube 26 is smoothly formed. Can be bent.

The flexible tube 26 goes from a linear state to a bent state by an external force. Therefore, when the tip portion 22 of the insertion portion 12 is inserted into the intestinal tract, for example, from the anus to the deep part of the large intestine, the flexible tube 26 receives, for example, the bending of the flexible tube 26 from the inner peripheral surface of the intestinal tract. It can be bent by applying an external force that exceeds the difficulty. Therefore, the flexible tube 26 of the insertion portion 12 is bent along the bending of the intestinal tube having flexibility like the large intestine.

In the first spiral tube 32, the close contact portion 33 is continuously formed over the entire length between one end and the other end. Further, in the second spiral tube 42, the close contact portion 43 is continuously formed over the entire length between one end and the other end of the second spiral tube 42. Therefore, when the external force applied to the flexible pipe 26 is removed or reduced, the adjacent portions 32b and 32c of the first wire 32a try to come into close contact with each other, and the second wire 42a is adjacent to the second wire 42a. The portions 42b and 42c try to come into close contact with each other. Therefore, with the contact portions 33a and 43a of the first spiral tube 32 and the second spiral tube 42 in FIG. 5 as fulcrums, the separation portions 33b and 43b of the first spiral tube 32 and the second spiral tube 42 It gets smaller and smaller. Further, the total length of the outer skin 44 along the longitudinal axis L also becomes shorter as the separation portions 33b and 43b of the first spiral tube 32 and the second spiral tube 42 gradually become smaller. That is, the length of the outer peripheral side portion 54 of the flexible pipe 26 and the length along the longitudinal axis L are brought close to the length of the inner peripheral side portion 52 of the flexible pipe 26. Therefore, the lengths of the first spiral tube 32, the second spiral tube 42, and the outer skin 44 along the longitudinal axis L shrink from the bent state to the linear state while shrinking toward the original state (straight line state). Returned to. Here, in both the first spiral pipe 32 and the second spiral pipe 42, a close contact force is continuously applied to the close contact portions 33 and 43 from the tip end to the base end. Therefore, the first spiral tube 32 and the second spiral tube 42 try to straighten the flexible tube 26, and improve the operability when straightening the intestinal tract such as the large intestine.

The exodermis 44 exerts an appropriate elastic force. The flexible pipe 26 according to the present embodiment extends at a position along the longitudinal axis L in a bent state rather than in a straight state. Therefore, in the exodermis 44 of the flexible pipe 26 according to the present embodiment, even if the bending state is the same, the total amount of extension of the outer peripheral side portion 54 is larger than that in the case where the position along the longitudinal axis L of the exodermis 44 does not extend. growing. The outer skin 44 of the flexible pipe 26 according to the present embodiment has a shorter length along the longitudinal axis L when it is in a linear state than in a bent state. Therefore, as the elongation length of the exodermis 44 increases from the linear state to the bent state, the reaction force for returning to the original length increases. Therefore, the flexible pipe 26 according to the present embodiment exhibits higher elasticity (reaction force) than when the position along the longitudinal axis L does not extend.

As described above, the flexible tube 26 can easily return the bent state to the linear state due to its elasticity. Therefore, in the flexible tube 26, for example, after the curved portion 24 exceeds an appropriate bending position of the intestinal tract, the bending portion of the intestinal tract is arranged in a substantially linear shape by utilizing the elasticity of the flexible tube 26. Therefore, the intestinal tract having a small bending radius, such as the sigmoid colon, is arranged in a substantially straight line. The substantially linear flexible tube 26 is easily advanced to the substantially linear intestinal tract. Therefore, the user can insert the tip portion 22 of the insertion portion 12 into the deep part of the intestinal tract.
As the bending state is returned to the linear state, the clearance between the outer peripheral surface of the first spiral tube 32 and the inner peripheral surface of the second spiral tube 42, that is, the inner peripheral surface of the outer layer portion 34 gradually becomes smaller. .. There is also a clearance between the first spiral tube 32 and the second spiral tube 42 when going from the bent state to the straight state. Therefore, the interference between the first spiral tube 32 and the second spiral tube 42 between the linear state and the bent state is suppressed.

In this way, the flexible tube 26 of the insertion portion 12 is appropriately bent according to the external force applied from the inner peripheral surface of the intestinal tract, and the elasticity of the flexible tube 26 makes the intestinal tract substantially linear. While repeating, the tip portion 22 of the insertion portion 12 is moved to the inner side of the intestinal tract.

(effect)
As described above, according to the flexible tube 26 of the insertion portion 12 of the endoscope 10 according to the present embodiment, the following can be said.

The diameter of the first spiral tube 32 shrinks as the total length extends along the longitudinal axis L. The diameter of the second spiral tube 42 is reduced as the total length extends along the longitudinal axis L. When the first spiral tube 32 and the second spiral tube 42 extend by the same length along the longitudinal axis L, the inner first spiral tube 32 has the outer layer portion 34 (outer second spiral tube 42). The amount of diameter reduction is larger than that. Therefore, when bending the flexible pipe 26 and when straightening the bent flexible pipe, it is not necessary to provide a clearance between the first spiral pipe 32 and the outer layer portion 34 in the flexible pipe 26. Also, the interference between the first spiral tube 32 and the outer layer portion 34 can be suppressed. Therefore, the flexible tube 26 can be bent smoothly, the outer diameter of the flexible tube 26 can be kept small, and the burden on the patient can be kept small, for example.

In the first spiral tube 32, the close contact portion 33 is continuously formed over the entire length between one end and the other end. Therefore, the first spiral tube 32 does not have a portion where the ease of bending / difficulty of bending changes sharply along the longitudinal axis L. Therefore, the first spiral tube 32 is the first when the user holds the proximal end side of the flexible tube 26 and pushes the tip end portion 22 of the insertion portion 12 into the tube hole, that is, toward the inner side of the intestinal tract. It is easy to transmit the pushing force applied to the spiral tube 32 toward the tip side. Therefore, when the tip 22 of the insertion portion 12 is pushed toward the inner side of the tube hole (intestinal tract), buckling or unintended bending of the flexible tube 26 is unlikely to occur, and the force is reliably transmitted to the tip 22. Will be done. Further, the second wire 42a of the second spiral tube 42 is formed by being spirally wound on the outside of the close contact portion 33 so that the number of turns is larger than that of the first spiral tube 32. Therefore, the flexible tube 26 can be bent into a smooth shape when bent, and can exhibit elasticity that improves the insertability into the tube hole (intestinal tract) over the entire length.
Therefore, according to the present embodiment, the flexible tube for an endoscope has good elasticity while suppressing interference between the first spiral tube 32 and the outer layer portion 34 on the outer side of the first spiral tube 32. 26 and the endoscope 10 can be provided.
The second spiral tube 42 has a close contact portion 43 continuously formed over the entire length between one end and the other end. Therefore, the second spiral tube 42 does not have a portion where the ease of bending / difficulty of bending changes sharply along the longitudinal axis L. Therefore, the second spiral tube 42 is the second spiral tube 42 when the user holds the proximal end side of the flexible tube 26 and pushes the tip end portion 22 of the insertion portion 12 toward the inner side of the tube hole (intestinal tract). In cooperation with the spiral tube 32 of No. 1, it is easy to transmit the pushing force toward the tip side.

In the first spiral tube 32, since the close contact portion 33 is continuously formed over the entire length between one end and the other end, the first spiral tube 32 can be uniformly processed over the entire length. Therefore, the first spiral tube 32 according to the present embodiment can be easily processed and can be processed at a lower cost than when a loosely wound portion is included in the space. Further, the second spiral tube 42 can be uniformly processed in the same manner as the first spiral tube 32. Therefore, the second spiral tube 42 is easy to process and can be processed at a lower cost than when a loosely wound portion is included in the middle.

The internal structure inside the first spiral tube 32 of the flexible tube 26 is made of a stretchable material. Therefore, the flexible pipe 26 can be expanded and contracted together with the expansion and contraction along the longitudinal axis L. Therefore, when the flexible tube 26 is appropriately deformed between the straight state and the bent state, the relative movement amount between the flexible tube 26 and the internal component can be reduced, and the first spiral can be reduced. It is possible to prevent the inner peripheral surface of the tube 32 from rubbing against or being caught by the internal components.

(First Modified Example of First Embodiment)
A modified example of the second wire 42a of the second spiral tube 42 will be described with reference to FIGS. 6 to 7B.

The second spiral tube 42 shown in FIG. 6 does not have a close contact portion 43. That is, the distal end side portion 42b and the proximal end side portion 42c of the second strand 42a of the second spiral tube 42 are formed as sparse windings that are separated from each other. The distal end side portion 42b and the proximal end side portion 42c may simply be in contact with each other in a state where no adhesive force is applied. At this time, it is sufficient that the condition that the pitch P2 of the second spiral tube 42 is smaller than the pitch P1 of the first spiral tube 32 is satisfied. Then, in this modified example, a part of the second spiral tube 42 is embedded in the inner peripheral surface of the exodermis 44. On the other hand, the inner peripheral surface of the second spiral tube 42 is in contact with or is in contact with the outer peripheral surface of the first spiral tube 32.

Even if the second spiral tube 42 of the outer layer portion 34 is loosely wound, the first spiral tube 32 has the close contact portion 33. When an external force is applied to the flexible tube 26, the entire length of the inner peripheral side portion (the portion indicated by reference numeral 52 in FIG. 5) of the second spiral tube 42 is restricted to the contact portion 33a of the first spiral tube 32. Does not shrink. Therefore, the first spiral tube 32 and the second spiral tube 42 extend along the longitudinal axis L. Therefore, as in the case where the second spiral pipe 42 has the close contact portion 43, the first spiral pipe 32 and the outer layer portion 34 extend along the longitudinal axis L to bend the flexible pipe 26.

Further, when the external force applied to the flexible tube 26 is removed or reduced, the adjacent portions 32b and 32c of the first wire 32a try to come into close contact with each other as described in the first embodiment. To do. Therefore, the separation portion 33b of the first spiral tube 32 gradually becomes smaller with the contact portion 33a of the first spiral tube 32 in FIG. 5 as a fulcrum. Further, the total length of the outer skin 44 also becomes shorter as the separating portion 33b of the first spiral tube 32 gradually becomes smaller. Therefore, the longitudinal axis L along the first spiral tube 32, the second spiral tube 42, and the outer skin 44 contracts toward the original state, and is returned from the bent state to the linear state. Here, in the first spiral tube 32, a contact force is continuously applied to the contact portion 33 from the tip end to the base end. Therefore, the first spiral tube 32 tries to straighten the flexible tube 26 in a straight line state, and improves operability when straightening a lumen such as a large intestine.

FIG. 7A shows an example in which the first spiral tube 32 has a winding direction α and the second spiral tube 42 has a winding direction β opposite to the winding direction α. FIG. 7B shows an example in which the first spiral tube 32 has a winding direction α and the second spiral tube 42 has the same winding direction α as the winding direction α of the first spiral tube 32. The winding direction α of the first spiral tube 32 and the winding direction α of the second spiral tube 42 may have the same or different twist angles θ (see FIG. 3A). In the flexible tube 26 of the example shown in FIGS. 7A and 7B, the exodermis 44 is not shown, and the second spiral tube 42 does not have the close contact portion 43.

As shown in FIG. 7A, when the first spiral tube 32 and the second spiral tube 42 are bent, contact is made between the adjacent portions 32b and 32c of the first wire 32a of the first spiral tube 32. A contact portion 33a to be maintained and a separation portion 33b to be separated are generated. When the first spiral tube 32 has a winding direction α and the second spiral tube 42 has a winding direction β, a wire is formed inside the wire 42a between the pitches P1 of the first spiral tube 32. The outer peripheral surface of 32a is always present. Therefore, it is prevented that the second spiral tube 42 tries to enter between the separating portions 33b of the first spiral tube 32.

As shown in FIG. 7B, when the first spiral tube 32 has a winding direction α and the second spiral tube 42 has a winding direction α, the second spiral has a pitch P1 of the first spiral tube 32. The pitch P2 of the tube 42 is smaller. Therefore, a position where the outer peripheral surface of the wire 32a does not exist may occur inside the wire 42a. Therefore, it is possible that the second spiral tube 42 tries to enter between the separating portions 33b of the first spiral tube 32. Therefore, when the winding directions of the first spiral tube 32 and the second spiral tube 42 are the same, the first spiral tube 32 and the second spiral tube 42 may be caught. Therefore, the first spiral tube 32 and the second spiral tube 42 according to the present embodiment may have the same winding direction, but are preferably opposite.

(Second modification of the first embodiment)
A modified example of the second wire 42a of the second spiral tube 42 will be described with reference to FIGS. 8A to 8C.

In the example shown in FIG. 8A, the cross section of the second strand 42a of the second spiral tube 42 is formed in a rectangular shape. When the length of the second spiral tube 42 changes along the longitudinal axis L, the second wire 42a moves along the winding direction indicated by the arrow β in FIG. 2B, and the second wire 42a Adjacent portions 42b, 42c of the above can be brought into contact with and separated from each other along the longitudinal axis L.

In the example shown in FIG. 8B, the distal end side portion 42b of the second strand 42a of the second spiral tube 42 is formed in a convex shape, and the proximal end side portion 42c is formed in a concave shape. Therefore, the tip end side portion 42b and the proximal end side portion 42c are fitted. Therefore, the distal end side portion 42b and the proximal end side portion 42c of the second strand 42a of the second spiral tube 42 are prevented from being displaced in the radial direction of the longitudinal axis L.
The tip side portion 42b is appropriately sharpened. It is preferable that the base end side portion 42c has a smaller contact area with respect to the tip end side portion 42b and is formed in a state where friction is not generated as much as possible.

In the example shown in FIG. 8C, similarly to the example shown in FIG. 8B, the distal end side portion 42b of the second strand 42a of the second spiral tube 42 is formed in a convex shape, and the proximal end side portion 42c is formed in a concave shape. There is. The tip end side portion 42b and the proximal end side portion 42c are fitted. Therefore, the distal end side portion 42b and the proximal end side portion 42c of the second strand 42a of the second spiral tube 42 are prevented from being displaced in the radial direction of the longitudinal axis L.
The tip side portion 42b is formed as an appropriate curved surface. It is preferable that the base end side portion 42c has a smaller contact area with respect to the tip end side portion 42b and is formed in a state where friction is not generated as much as possible.

As described above, the cross section of the second strand 42a of the second spiral tube 42 is appropriately formed.

(Third variant of the first embodiment)
A modified example of the first spiral tube 32 will be described with reference to FIG.

The first spiral tube 32 shown in FIG. 9 has a loosely wound portion 35 at a part between one end and the other end. Therefore, in the example shown in FIG. 9, the first spiral tube 32 does not have the close contact portion 33 continuously formed from one end to the other end. The loosely wound portion 35 is preferably formed in the vicinity of, for example, the base end side mouthpiece 26b of the flexible pipe 26 in the first spiral pipe 32. The position of the loosely wound portion 35 is, for example, arranged inside the break stopper 18a or at a position close to the break stopper 18a.

The user usually grips the flexible tube 26 at a position closer to the tip portion 22 than the portion where the loosely wound portion 35 is formed. Therefore, the force transmission from the user to the tip portion 22 is maintained in the same manner as in the example described in the first embodiment, and hardly changes.

(Fourth Modified Example of First Embodiment)
A modified example of the outer layer portion 34 will be described with reference to FIG.

In the first embodiment, the second spiral tube 42 and the outer skin 44 of the outer layer portion 34 have been described as being integrated. In the example shown in FIG. 10, the second spiral tube 42 of the outer layer portion 34 and the outer skin 44 are separated from each other. In this case, the second spiral tube 42 is provided between the inner peripheral surface of the outer skin 44 and the outer peripheral surface of the first spiral tube 32. The second wire 42a of the second spiral pipe 42, which is narrower along the longitudinal axis L than the first wire 32a of the first spiral pipe 32, is the first spiral outside the close contact portion 43. It is formed by being spirally wound so that the number of turns is larger than that of the tube 32. Therefore, similarly to the first embodiment described above, it is possible to provide the flexible tube 26 having good elasticity while suppressing the interference between the first spiral tube 32 and the outer layer portion 34.

(Fifth Modified Example of First Embodiment)
An example of modification of the outer layer portion 34 will be described with reference to FIG.

In the first embodiment including each modification, it has been described that the outer peripheral surface of the first spiral tube 32 and the inner peripheral surface of the second spiral tube 42 are in contact with each other or can be in contact with each other. FIG. 11 shows an example in which the second spiral tube 42 of the outer layer portion 34 is embedded in the outer skin 44 so as to be completely enclosed as well as a part thereof. In this case, the second spiral tube 42 is provided between the exodermis 44 and the first spiral tube 32. Even if the flexible pipe 26 in this case is bent, the diameter reduction and the diameter expansion of the second spiral pipe 42 are regulated by the outer skin 44. Therefore, it is less likely to be bent than the flexible pipe 26 described in the first embodiment including each modification.
The second spiral tube 42 may be completely enclosed in the outer skin 44 only for an appropriate length of the flexible tube 26, or may extend over the entire length.

(Second Embodiment)
Next, the second embodiment will be described with reference to FIGS. 12 to 14B. This embodiment is a modification of the first embodiment including each modification, and the members having the same or the same functions as the members described in the first embodiment are designated by the same reference numerals as much as possible, and are described in detail. The description is omitted.

As shown in FIG. 12, the second spiral tube 42 is formed in multiple layers. The second spiral tube 42 is formed here in two layers and has an inner layer 45 and an outer layer 47.

The strand 45a of the inner layer 45 has a distal end side portion 45b directed toward the distal end side and a proximal end side portion 45c directed toward the proximal end side. The strand 47a of the outer layer 47 has a distal end side portion 47b directed toward the distal end side and a proximal end side portion 47c directed toward the proximal end side. It is preferable that the pitches of the inner layer 45 and the outer layer 47 are the same or smaller in the outer layer 47. Therefore, the inner layer 45 and the outer layer 47 have the same diameter reduction amount when the same amount of elongation occurs, or the outer layer 47 has a smaller diameter.

The winding direction β of the wire 45a of the inner layer 45 is opposite to the winding direction α of the first spiral tube 32. The winding direction α of the wire 47a of the outer layer 47 is opposite to the winding direction β of the inner layer 45. That is, the winding direction α of the outer layer 47 is the same direction as the winding direction α of the first spiral tube 32. The inner layer 45 preferably has a close contact portion 46 continuously formed over the entire length between one end and the other end. The close contact portion 46 is wound in a state in which adjacent portions 45b and 45c of the inner layer 45 have an initial tension (preload) in a direction of compressing each other along the longitudinal axis L and are in close contact with each other. It is preferable that the outer layer 47 has the close contact portion 48 continuously formed over the entire length between one end and the other end. The close contact portion 48 is wound in a state in which adjacent portions 47b and 47c of the outer layer 47 have an initial tension (preload) in a direction of compressing each other along the longitudinal axis L and are in close contact with each other.
In FIG. 12, the inner strand (second strand) 45a of the inner layer 45 may be formed as a loose winding. Similarly, in FIG. 12, the outer strand (second strand) 47a of the outer layer 47 may be formed as a loose winding.

The first wire 32a of the first spiral tube 32 is right-handed, the inner wire (second wire) 45a of the inner layer 45 of the second spiral tube 42 is left-handed, and the second spiral tube 42. It is assumed that the outer wire (third wire) 47a of the outer layer 47 of the above is right-handed.

The case where the inner wire 45a of the inner layer 45 is, for example, left-handed will be described as an example. In the normal state where the inner layer 45 is shown in FIG. 13A (a state in which an external force other than gravity is not applied), one end side (for example, the tip side) of the inner layer 45 is fixed at the position indicated by the symbol FE to the one end side. Suppress the rotation of. In this state, as shown in FIG. 13B, when the position indicated by the symbol M on the other end side of the inner layer 45 is twisted so as to move in the direction of the arrow α (right direction), the other end side of the inner layer 45 ( For example, on the base end side), the diameter is smaller than in the normal state shown in FIG. 13A. Since one end side of the inner layer 45 is fixed, the diameter is unlikely to change with respect to a normal state. Further, when the position indicated by the symbol M on the other end side of the inner layer 45 is twisted from the normal state shown in FIG. 13A so as to move in the direction of the arrow β (leftward) as shown in FIG. 13C, the inner layer is twisted. On the other end side of 45, the diameter is larger than in the normal state shown in FIG. 13A. Since one end side of the inner layer 45 is fixed, the diameter is unlikely to change with respect to a normal state.

The first wire 32a of the first spiral tube 32 and the second wire 42a of the second spiral tube 42 are right-handed. Although not shown, the first spiral tube 32 and the second spiral tube 42 are in a normal state (a state in which an external force other than gravity is not applied) as in the inner layer 45 shown in FIG. 13A. The rotation of one end side is suppressed by fixing one end side of each of the pipe 32 and the second spiral pipe 42. In this state, when the positions indicated by the symbols M of the first spiral tube 32 and the second spiral tube 42 are twisted so as to move in the direction of the arrow α, the first spiral tube 32 and the second spiral tube 42 are twisted. The other end side of each of the above has a larger diameter than in the normal state. When the position indicated by the symbol M of the first spiral tube 32 and the second spiral tube 42 is twisted so as to move in the direction of the arrow β, the other of the first spiral tube 32 and the second spiral tube 42, respectively. The diameter of the end side is smaller than that in the normal state.

The left side in FIGS. 14A and 14B is the tip end side of the flexible pipe 26, and the left side is the proximal end side of the flexible pipe 26.

As shown in FIG. 14A, when the user holds an appropriate position of the flexible tube 26 and twists the flexible tube 26 to the right (direction indicated by the arrow α), the diameter of the first spiral tube 32 expands. The inner layer 45 has a reduced diameter, and the outer layer 47 has a larger diameter. The first spiral tube 32 and the inner layer 45 of the second spiral tube 42 interfere with each other, and the expansion / contraction between the first spiral tube 32 and the inner layer 45 of the second spiral tube 42 is stopped. Until the first spiral tube 32 and the inner layer 45 of the second spiral tube 42 interfere with each other, there is play in the twist of the flexible tube 26, and the twist angle of the portion held by the user is flexible. It may be different from the twist angle of the tip of the tube 26. In the flexible tube 26, there is no play in twisting the flexible tube 26 from the time when the first spiral tube 32 and the inner layer 45 of the second spiral tube 42 interfere with each other. Therefore, when the flexible tube 26 is further twisted from the time when the first spiral tube 32 and the inner layer 45 of the second spiral tube 42 interfere with each other, the twist angle of the portion held by the user is substantially the flexible tube. It is the twist angle of the tip of 26.

As shown in FIG. 14B, when the user holds an appropriate position of the flexible tube 26 and twists the flexible tube 26 to the left (direction indicated by the arrow β), the diameter of the first spiral tube 32 is reduced. The inner layer 45 has a larger diameter, and the outer layer 47 has a smaller diameter. The inner layer 45 and the outer layer 47 of the second spiral tube 42 interfere with each other, and the expansion / contraction between the inner layer 45 and the outer layer 47 of the second spiral tube 42 is stopped. Until the inner layer 45 and the outer layer 47 of the second spiral tube 42 interfere with each other, there is play in the twist of the flexible tube 26, and the twist angle of the portion held by the user is the twist angle of the flexible tube 26. It may be different from the twist angle of the tip. In the flexible tube 26, there is no play in twisting the flexible tube 26 from the time when the inner layer 45 and the outer layer 47 of the second spiral tube 42 interfere with each other. Therefore, when the flexible tube 26 is further twisted from the time when the inner layer 45 and the outer layer 47 of the second spiral tube 42 interfere with each other, the twist angle of the portion held by the user is substantially the tip of the flexible tube 26. It is the twist angle of the part.

As described above, in the flexible pipe 26 according to the present embodiment, the inside of the outer skin 44 is laminated in three layers by the first spiral pipe 32, the inner layer 45 and the outer layer 47 of the second spiral pipe 42. Moreover, both ends of the flexible pipe 26 are fixed to, for example, the caps 26a and 26b as described in the first embodiment. Then, the clearance between the outer peripheral surface of the first spiral tube 32 and the inner peripheral surface of the inner layer 45 of the second spiral tube 42, and the outer peripheral surface of the inner layer 45 of the second spiral tube 42 and the outer layer 47. The clearance with the inner peripheral surface may or may not be present as described in the first embodiment. In particular, in the absence of both clearances, when the user twists the flexible tube clockwise, there is no play as described above, and the first spiral tube 32, the inner layer 45 and the outer layer 47 of the second spiral tube 42 Almost no diameter reduction / expansion. Therefore, the first spiral tube 32 and the inner layer 45 of the second spiral tube 42 interfere with each other immediately after the start of twisting, and the twisting force of the portion held by the user is directly applied to the tip of the flexible tube 26. Reportedly. Similarly, when the user twists the flexible tube 26 counterclockwise, there is no play described above, and the inner layer 45 and the outer layer 47 of the first spiral tube 32 and the second spiral tube 42 are almost reduced in diameter / expanded. No diameter. Therefore, the inner layer 45 and the outer layer 47 of the second spiral tube 42 interfere with each other immediately after the start of twisting, and the twisting force of the portion held by the user is directly transmitted to the tip of the flexible tube 26.

As described above, in the flexible pipe 26 according to the present embodiment, the inside of the outer skin 44 is laminated in three layers. Therefore, the flexible tube 26 can improve the twist resistance of the flexible tube 26 as compared with the case where the inside of the outer skin 44 has one or two layers, and can extend the product life. Further, the flexible pipe 26 according to the present embodiment has a clearance between the outer peripheral surface of the first spiral pipe 32 and the inner peripheral surface of the inner layer 45 of the second spiral pipe 42, and the second spiral pipe 42. By adjusting the clearance between the outer peripheral surface of the inner layer 45 and the inner peripheral surface of the outer layer 47, the twisting force of the flexible pipe 26 can be easily transmitted to the tip end portion of the flexible pipe 26. Therefore, by using the flexible tube 26 according to the present embodiment, the insertability of the insertion portion 12 into the body cavity can be improved.

The dimensional relationship between the second spiral tube 42 and the first spiral tube 32 is such that the inner diameter of the second spiral tube 42 is slightly larger than the outer diameter of the first spiral tube 32, and even if there is a small gap. Alternatively, the second spiral tube 42 and the first spiral tube 32 may have a “tightening” relationship.

Further, the wire 45a of the inner layer 45 and the wire 47a of the outer layer 47 constituting the second spiral tube 42 may be formed by combining materials having the same material, cross-sectional shape, and the like. It may be formed by combining those having different cross-sectional shapes and the like.

Further, the second spiral tube 42 is not limited to the multi-layer having two layers, and the wire may be wound around the multi-layer of three or more layers as needed.

(Third Embodiment)
Next, the third embodiment will be described with reference to FIG. This embodiment is a modification of the first embodiment and the second embodiment including each modification, and is a member having the same function as the member described in the first embodiment and the second embodiment. Have the same reference numerals as possible, and detailed description thereof will be omitted.

As shown in FIG. 15, a blade (reticulated tube) 49 is arranged on the outer periphery of the second spiral tube 42. The blade 49 is formed into a cylindrical shape by weaving a thin metal wire made of stainless steel, for example, into a fibrous form. In this case, the outer layer portion 34 is formed of a second spiral tube 42, a blade 49, and an outer skin 44. A second spiral tube 42 is wound inside the blade 49, and the blade 49 is covered with an exodermis 44. That is, the second spiral tube 42 is different from the blade 49. A clearance may be formed between the second spiral tube 42 and the blade 49.

When the flexible tube 26 is bent, the blade 49 tends to collapse in the radial direction. However, the second wire 42a of the second spiral tube 42 inside the blade 49 has sufficient rigidity in the radial direction with respect to the blade. Therefore, even if the flexible tube 26 is bent and the blade 49 tries to be crushed in the radial direction, the rigidity of the second spiral tube 42 can prevent the flexible tube 26 from being crushed in the radial direction.

In FIG. 15, an example in which the second spiral tube 42 is formed as one layer is shown, but the plurality of layers (inner layer 45 and outer layer 47) shown in FIG. 12 are the second of the one layer shown in FIG. It may be arranged instead of the spiral tube 42 of.

In the embodiment including each of the above-described modifications, an example in which the flexible tube 26 is used as a part of a medical endoscope 10 having an insertion portion 12 inserted into a hole such as a body cavity has been described. If it can be used as a part of the insertion portion 12 inserted into the hole, the use of the flexible tube 26 is not limited to the medical endoscope 10, for example, an industrial endoscope.
The endoscope 10 according to the embodiment including each of the above-described modifications has a structure in which the endoscope 10 itself has an observation optical system, and the observation optical system is a flexible tube via a channel (not shown) or the like. It may also include insertion from the proximal end side of the 26 to the distal end side. The flexible tube 26 can be used not only for the endoscope 10 but also for a catheter or the like that does not involve observation.

So far, some embodiments have been specifically described with reference to the drawings, but the present invention is not limited to the above-described embodiments, and all the embodiments performed without departing from the gist thereof. Including. As a matter of course, one endoscope 10 can be realized by appropriately combining each of the above-described embodiments and modifications.

Claims (17)

A plate-shaped first wire is spirally wound, and a first contact portion in which adjacent portions of the first wire are in close contact with each other is formed over the entire length along a longitudinal axis . Spiral tube and
A flexible exodermis provided on the outer peripheral side of the first spiral tube and bent with respect to the longitudinal axis together with the first spiral tube.
A second wire is spirally wound between the exodermis and the first spiral tube, and the width along the longitudinal axis is narrower than that of the first wire. It has a second spiral tube having a larger number of turns per unit length than the first spiral tube on the outside of the close contact portion of 1.
For endoscopes, when the second spiral tube is linearized along the longitudinal axis together with the outer skin, at least a part of the second wire is always in contact with the outer peripheral surface of the first spiral tube. Flexible tube. When the first spiral tube and the second spiral tube are bent together with the outer skin, at least a part of the outer skin is in a linear state of the outer skin, the first spiral tube and the second spiral tube. The flexible tube according to claim 1, which extends along the longitudinal axis as compared with the case of. According to claim 1, when the second spiral tube is linearized along the longitudinal axis together with the exodermis, at least a part of the second wire is always in contact with the inner peripheral surface of the exodermis. The flexible tube described. The flexible pipe according to claim 1 , wherein the first contact portion is in close contact with each other along the longitudinal axis in a state where the adjacent portions are in close contact with each other so as to press each other along the longitudinal axis. At both ends of the first spiral tube separated along the longitudinal axis,
The flexible tube according to claim 1 , wherein a mouthpiece is provided to prevent the first spiral tube from having a difference in elongation with respect to the exodermis when bent from a linear state together with the exodermis. When the first spiral tube and the second spiral tube together with the exodermis reach a bent state from a linear state, at least a part of the flexible tube includes an inner peripheral side portion and the inner circumference. An outer peripheral side portion on the opposite side of the longitudinal axis with respect to the side portion is formed.
When the flexible tube changes from the straight state to the bent state,
The length of the inner peripheral side portion of the flexible tube is maintained between the linear state and the bent state, and the length along the longitudinal axis of the flexible tube and the length of the outer peripheral side portion. Is the flexible tube according to claim 1, which is stretched with respect to the linear state in the bent state. The possibility according to claim 6 , wherein when the flexible tube reaches the bent state, the adjacent portions maintain a state of being in contact with each other on the inner peripheral side portion and are separated from each other on the outer peripheral side portion. Flexible tube. The second wire is laminated in a plurality of layers in the radial direction.
The flexible tube according to claim 1, wherein the second strands of the plurality of layers have opposite winding directions. The flexible tube according to claim 8 , wherein the layer adjacent to the outer side of the first wire in the radial direction of the second wire has a winding direction opposite to that of the first wire. The flexible tube according to claim 1, wherein the second spiral tube is provided between the inner peripheral surface of the exodermis and the outer peripheral surface of the first spiral tube. The flexible tube according to claim 1, wherein the second spiral tube is at least partially embedded in the exodermis. A plate-shaped first wire is spirally wound, and a first contact portion in which adjacent portions of the first wire are in close contact with each other is formed over the entire length along a longitudinal axis . Spiral tube and
A flexible exodermis provided on the outer peripheral side of the first spiral tube and bent with respect to the longitudinal axis together with the first spiral tube.
A second wire is spirally wound between the exodermis and the first spiral tube, and the width along the longitudinal axis is narrower than that of the first wire. It has a second spiral tube having a larger number of turns per unit length than the first spiral tube on the outside of the close contact portion of 1.
The second spiral tube has a second contact portion that is spirally wound by the second wire and the adjacent portions of the second wire are in close contact with each other along the longitudinal axis. A flexible tube for an endoscope formed over. The flexible tube according to claim 12 , wherein the second contact portion is in close contact with each other in a state where adjacent portions along the longitudinal axis have an initial tension of pressing against each other along the longitudinal axis. The second wire is laminated in a plurality of layers in the radial direction.
The flexible tube according to claim 12 , wherein the second strands of the plurality of layers have opposite winding directions. The flexible tube according to claim 14 , wherein the layer adjacent to the outer side of the first wire in the radial direction of the second wire has a winding direction opposite to that of the first wire. The flexible tube according to claim 12 , wherein the second spiral tube is provided between the inner peripheral surface of the exodermis and the outer peripheral surface of the first spiral tube. The flexible tube according to claim 1 and
The tip portion provided on the tip side of the flexible tube and
An endoscope having an operation unit provided on the base end side of the flexible tube.

Images