JPWO2016203821A1 - Endoscope using flexible tube and flexible tube - Google Patents

Abstract

The flexible tube has a cylindrical shape that covers the natural-length spiral tube and includes an outer layer portion having an outer layer portion having an inner diameter larger than the outer diameter of the spiral tube. Due to the gap due to the difference from the inner diameter, the portion where the spiral tube is in non-contact with the inner peripheral surface of the outer layer portion that contacts on the outer peripheral surface in the radial direction of the spiral tube remains between the straight state and the maximum curved state. The diameter of the spiral tube and the diameter of the outer layer portion are set.

Description

  The present invention relates to a flexible tube that is mounted on an insertion device and is flexible and has good elasticity, and an endoscope using the flexible tube.

  In general, an insertion portion of an endoscope which is one of insertion devices is long and is used by being inserted into a lumen such as a body cavity where a curved portion exists. The insertion portion includes a distal end portion on the distal end side to be inserted, a bending portion continuing to the proximal end side of the distal end portion, and a flexible tube continuing to the bending portion and connecting to the operation portion.

  When the flexible tube is inserted into the tube hole, the flexible tube is inserted following the bending portion, and is bent so as to be suitable for the bending state in the tube hole, and is responsible for transmitting the propulsive force to the inserted distal end portion. As a part of the configuration that realizes the flexibility, there is known a spiral tube disposed inside a flexible tube disclosed in Patent Document 1: Japanese Patent Application Laid-Open No. 2013-97327. In this spiral tube, a so-called densely wound portion and a loosely wound portion that is spirally wound in a spiral manner are alternately wound so that a thin, narrow and long metal plate (elementary wire) is densely wound spirally so as not to have a gap. The structure is wound so as to be continuous, and has elasticity by adding initial tension while giving flexibility.

  The flexible tube described above is configured to be covered with an outer layer portion of a mesh-like mesh tube and an outer skin portion of an elastic body so as to cover the outer peripheral surface of the spiral tube. Usually, the spiral tube and the outer layer portion are fixed at both ends, and can move without being in close contact with each other. When the spiral tube is bent in this configuration, the spiral tube moves in accordance with the bending in the outer layer portion. If this movement is not performed smoothly, a load is applied locally, and the bending operation becomes difficult.

  Also, when the densely wound portion and the loosely wound portion that are alternately and continuously arranged are included in the curved range, the loosely wound portion that is easy to bend as compared to the densely wound portion bends greatly, so that it does not have a smooth arc shape but is angular. It will be distorted into the polygonal shape which a part produces. At the same time, since a large pressure is also applied to the closely wound portion, a situation in which the inner side and the outer side of the strands overlap each other (so-called pitch shift) continuously occurs between adjacent strands of the spiral tube. At this time, it is assumed that the surgeon performing the operation feels a sense of incongruity even if it is determined that the failure is not a failure because the repulsion and vibrations that are continuous and strong are transmitted along with the shift sound.

  Therefore, the present invention provides a flexible tube that has a spiral tube in which a densely wound portion and a loosely wound portion are combined, and can be bent smoothly without any sense of incongruity when bent, and an endoscope using the flexible tube. To do.

  The flexible tube according to the embodiment according to the present invention includes a densely wound portion having a portion in which a plate-like strand is wound spirally and stretched along the longitudinal axis direction, and the adjacent strands are in close contact with each other. A spiral tube having a sparsely wound portion in which the adjacent strands are separated from each other, and a cylindrical shape that covers the natural length of the spiral tube, and has a larger inner diameter than the outer diameter of the spiral tube An outer layer portion is provided, and on the outer peripheral surface in the radial direction of the spiral tube during the period from the straight state to the maximum curved state due to a gap due to the difference between the outer diameter of the spiral tube and the inner diameter of the outer layer portion. The diameter of the spiral tube and the diameter of the outer layer portion are set so that a portion that is not in contact with the inner peripheral surface of the outer layer portion that is in contact remains.

FIG. 1 is a diagram showing an external configuration of an endoscope main body. FIG. 2 is a diagram conceptually illustrating a cross-sectional configuration of the flexible tube according to the first embodiment. FIG. 3 is a diagram conceptually showing the flexible tube in a bent state. FIG. 4 is a diagram illustrating a cross-sectional configuration example of the flexible tube according to the second embodiment. FIG. 5 is a diagram illustrating a cross-sectional configuration example of a flexible tube according to a modification of the second embodiment. FIG. 6 is a diagram conceptually showing a cross-sectional configuration of the flexible tube of the third embodiment. FIG. 7 is a diagram showing a conceptual configuration of a mesh tube in which a coil is knitted in the third embodiment. FIG. 8A is a diagram showing a conceptual shape when the flexible tube is bent. FIG. 8B is a diagram showing a cross-sectional configuration of the curved portion AA in FIG. 8A. FIG. 9 is a diagram illustrating an example of coils having different cross-sectional shapes. FIG. 10 is a diagram illustrating a configuration example of a flexible tube according to a first modification of the third embodiment. FIG. 11 is a diagram illustrating a configuration example of a flexible tube according to a second modification of the third embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an external configuration of an endoscope main body to which the flexible tube of the present embodiment is applied.
The endoscope 1 includes an elongated insertion portion 2 that is inserted into a lumen or the like, and an operation portion 3 that is connected to the proximal end side of the insertion portion 2 and operates the endoscope 1.

  The endoscope 1 according to this embodiment is an endoscope for observing the inside of a living body and an endoscope for observing the inside of a metal pipe, an internal combustion engine, or the like, that is, a so-called industrial endoscope. Can also be applied. Note that the elasticity and initial tension described in the following embodiments suggest the following meanings. “Resistance means that when a force is applied from the outside, the flexible tube is easy to return from its bent state to its original shape (straight state)”. This suggests that it is an internal force (adhesion force) generated between adjacent strands so as not to be deformed when spirally wound. In the following description, it is assumed that the resilience and initial tension cause the same effect when an external force is applied.

  The insertion portion 2 mainly includes a distal end portion 11 made of a hard member on which an imaging optical system and an illumination window are mounted, a bending portion 12 that is connected to the proximal end side of the distal end portion 11 and is actively curved, and further curved. And a flexible flexible tube 13 that continues to the portion 12 and connects the operation portion main body 3a. The insertion portion 2 is separately provided with a through-hole for fitting a treatment instrument, a passage for supplying a cleaning liquid and an air supply / aspiration, etc. Each opening of these through-holes and passages is formed in the distal end surface 11a.

  The bending portion 12 has a known configuration in which a plurality of annular piece members (not shown) rotatably connect each other's joint portions, and the joint portions are alternately provided in at least orthogonal directions. A plurality of wires (not shown) connected to the piece member on the distal end side are connected to the angle knobs 14 and 15 provided in the operation unit 3, and the angle knobs 14 and 15 are rotated to operate the wires. To bend the bending portion 12 actively.

  The operation unit 3 has a substantially rectangular parallelepiped shape that the operation unit main body 3a is easy to hold with one hand, the universal cable 5 is connected to the upper part of the side surface, and the base end side of the bending unit 12 is connected to the lower end, It has a substantially L-shaped form. The universal cable 5 includes an image / control signal cable (not shown), a power cable, a light guide that transmits illumination light, and the like, and is covered with a covering member made of resin. A connector terminal 6 is provided at the end of the cable. Yes. The connector terminal 6 is connected to at least an image processing unit and a light source unit (not shown). The endoscope 1 further includes a monitor and an input device as a system configuration, and a pump device for air supply / water supply and suction, a device for a treatment tool, and the like are provided as necessary.

  Two angle knobs (14, 15) for bending the bending portion 12 are arranged on the front surface of the operation portion main body 3a so as to be at the same rotation center position. A suction switch 16 and an air / water supply switch 17 are juxtaposed at a position where the finger can be caught on the side surface opposite to the side surface on which the universal cable 5 is provided. Furthermore, a photographing switch 18 including a shutter switch for photographing an endoscopic image by the imaging optical system is provided on the upper surface of the operation unit main body 3a.

  The angle knobs 14 and 15 of the present embodiment each have a UD knob (first operation portion) 14 that bends the bending portion 12 in the up / down direction (first axial direction) by rotation, It comprises an RL knob (second operation part) 15 that bends in a left / right (second axial direction) perpendicular to the first axial direction. In this embodiment, a manual angle knob is shown as an example, but an angle knob including a motor switch that is bent by a driving source such as a motor may be used.

[First Embodiment]
Next, the structure of the flexible tube 13 according to the first embodiment will be described.
FIG. 2 is a diagram conceptually showing a cross-sectional configuration of the flexible tube 13 (insertion portion 2) of the present embodiment. FIG. 3 is a diagram conceptually showing the flexible tube in a bent state.

  The flexible tube 13 has a shape of a hollow pipe, and although not shown, a wire for bending operation of the bending portion 12 and a light guide (optical fiber cable) for guiding illumination light are provided inside. ) And a signal cable for transmitting an imaging signal, and a forceps channel and an air / water supply pipe (tube) are further provided according to design specifications.

  The flexible tube 13 includes a spiral tube (flex tube) 21 and an outer layer portion 20 that covers the outer circumferential surface of the spiral tube 21 with a clearance (gap) S, which will be described later, which is a gap having a predetermined interval. Yes. As shown in FIG. 2, the spiral tube 21 is made of a long thin metal plate (flex strand) having a narrow width and a rectangular or parallelogram cross section so that there is no gap between adjacent ones. And a densely wound portion 21a wound spirally and a loosely wound portion 21b wound spirally with an interval according to the design. The spiral tube 21 is formed by winding the closely wound portion 21a and the loosely wound portion 21b so as to have initial tension along the longitudinal direction.

  The outer layer portion 20 includes a mesh-like mesh tube (blade) 22 in which linear strands (metal fibers or the like) are knitted, and an outer skin made of a resin tube having water-tight coating on the outer peripheral surface of the mesh tube 22 and having elasticity. The portions 23 are integrally formed so as to be laminated. The outer layer portion 20 of the present embodiment has uniform elasticity and hardness as a whole, but the elasticity and hardness can be entirely or partially changed by changing the thickness or material of each. It is also possible to change.

  Further, the flexible tube 13 is covered with the outer layer portion 20 and fixed to the inner surface of the outer skin portion 23 by covering the outer peripheral surfaces of both ends of the spiral tube 21 in the natural length state, so that the entire length along the axial direction of the longitudinal axis thereof. Is defined so that the overall length is substantially constant without changing. The fixing method may be a general fixing method, and for example, solder, adhesive, laser welding or the like is used.

  As shown in FIG. 3, the spiral tube 21 bends when an external force is applied, and deforms into an arc state. When the densely wound portion 21a is bent, adjacent wires on the outer peripheral side are separated from each other, and the distance outside the arc is longer than the length in the longitudinal axis direction when the spiral tube 21 is in a straight state. As shown by the arrow, the distance increased with respect to the outer layer portion 20 is dispersed by moving the spiral tube 21 in the mesh tube 22, and the majority is absorbed by the loosely wound portion 21b.

When the flexible tube 13 is bent, the cylindrical outer layer portion 20 bends without extending the length of the central axis, but the densely wound portion 21a bends so that the central axis length thereof is extended. In order to absorb the elongation of the densely wound portion 21a generated with respect to the outer layer portion 20 whose length does not extend when the flexible tube 13 is bent, the extended portion of the densely wound portion 21a slides in the direction of the loosely wound portion 21b. As a result, the sparse winding part shrinks. During this sliding, the smaller the friction between the densely wound portion 21a and the mesh tube 22, the smoother the movement.
In the present embodiment, in order to reduce such friction, a clearance (gap) S is provided between the spiral tube 21 and the mesh tube 22 as shown in FIG. That is, the gap S is a dimensional difference between the outer peripheral diameter (outer surface diameter) of the spiral tube 21 and the inner peripheral diameter (inner peripheral surface diameter) of the cylindrical outer layer portion 20. For example, the gap is preferably equal to or less than twice the thickness of the wire.

  By providing the gap S, the linear spiral tube 21 and the mesh tube 22 are not in contact by the gap S except that a part of them is brought into contact by the action of gravity. As shown in FIG. 3, the spiral tube 21 can move smoothly even when the outer surface of the spiral tube 21 contacts the inner peripheral surface of the mesh tube 22 when the spiral tube 21 is bent to the maximum. In addition, the diameter of the outer layer portion 20 of the spiral tube 21 is set so that a gap S in which the spiral tube 21 and the mesh tube 22 are not in contact remains inside the curve. That is, when the spiral tube 21 is in the maximum curved state due to the gap generated by the difference between the outer diameter of the spiral tube 21 and the inner diameter of the mesh tube 22 of the outer layer portion 20, The outer diameter of the spiral tube 21 and the inner diameter of the mesh tube 22 are set so that a portion that is not in contact with the inner peripheral surface of the mesh tube 22 remains. By leaving this gap S, the spiral tube 21 can gradually move according to the progress of the bending, and the pressure applied to the spiral tube 21 is dispersed.

  According to the present embodiment, the difference in length between the spiral tube 21 and the outer layer portion 20 that occurs when the flexible tube 13 is bent is that there is a gap between the tightly wound portion 21 a of the spiral tube 21 and the outer layer portion 20. By providing, it moves smoothly by non-contact or low friction, and becomes easy to be absorbed by the adjacent sparsely wound portion 21b. Therefore, it is avoided that a large pressure is applied to the closely wound portion 21a of the spiral tube 21, and it is possible to prevent the occurrence of a shift sound, repulsion and vibration due to a pitch shift of the strands. Further, since pressure is applied to the entire bent portion of the bent flexible tube 13, the shape of the arc is not angular.

[Second Embodiment]
FIG. 4 is a diagram illustrating a cross-sectional configuration example of the flexible tube 13 provided with a gap in the second embodiment.
In the present embodiment, the diameter Φ1 of the densely wound portion 25a is made smaller than the diameter Φ2 of the loosely wound portion 25b with respect to the spiral tube 25 (Φ1 <Φ2), whereby the inner peripheral surface of the mesh tube 22 is reduced. The gap S1 is configured to exist. In this example, the diameter Φ2 is preferably less than twice the diameter Φ1. Further, in this configuration, a gap S2 narrower than the gap S1 is provided so as to bend more smoothly with respect to the loosely wound portion 25b. The gap S2 is not particularly limited as long as the loosely wound portion 25b can move along with expansion and contraction.

  Similar to the first embodiment, the difference in length between the spiral tube 25 and the outer layer portion 20 that occurs when the flexible tube 13 is bent is that the tightly wound portion 25 a of the spiral tube 25 is between the outer layer portion 20 and the outer tube portion 20. By providing a gap in the gap, it moves smoothly with no contact or with low friction and is absorbed by the adjacent loosely wound portions 25b.

  In the present embodiment, since the gap S2 of the loosely wound portion 25b is narrower than the gap S1 of the densely wound portion 25a, the diameter of the loosely wound portion 25b is larger when bent. The area that contacts quickly and contacts is large. As a result, the frictional force acts on the loosely wound portion 25b more than the densely wound portion 25a, and the hardness against bending is increased. On the other hand, if the gap is large and the mesh tube 22 is not contacted, the hardness against bending becomes soft.

  Therefore, by changing the size of the gap between the spiral tube 25 and the mesh tube 22 at an arbitrary position in the longitudinal axis direction of the flexible tube 13, that is, by changing the diameter of the spiral tube 25, the hardness against bending is increased. Can be changed. That is, the hardness against bending of the flexible tube 13 can be changed regardless of the hardness of the outer layer portion 20. For example, the insertion property is improved by hardening the proximal end side and softening the distal end side. In this example, the distance between two gaps is taken as an example, but by changing the diameter of the spiral tube 25 as appropriate, it is possible to change the hardness in a plurality of stages.

  In this embodiment, with respect to the spiral tube 25 having the densely wound portion 25a and the loosely wound portion 25b, the diameter of the loosely wound portion 25b is made larger than that of the densely wound portion 25a, thereby narrowing the gap with the mesh tube 22. ing. With this configuration, the hardness of the loosely wound portion 25b and the densely wound portion 25a with respect to bending can be made the same. As a result, since pressure is applied to the entire bent portion of the bent flexible tube 13, the shape of the arc is not angular.

  Furthermore, the proximal end portion connected to the operation portion 3 and the distal end portion connected to the bending portion 12 in the flexible tube can be made hard by narrowing the gap between the spiral tube 25 and the mesh tube 22. is there. In the present embodiment, the spiral tube 25 having the densely wound portion 25a and the loosely wound portion 25b has been described as an example. However, a hard tube having only the densely wound portion or a spiral tube having only the loosely wound portion is similarly hard. Changes can be made.

  In the present embodiment, the outer layer portion 20 maintains the same inner diameter in the long axial direction, and a gap is generated between the outer layer portion 20 due to the difference in diameter between the densely wound portion 25a and the loosely wound portion 25b of the spiral tube 25. Therefore, the outer diameter of the outer layer part 20 can be realized with the same diameter.

[Modification of Second Embodiment]
FIG. 5 is a diagram illustrating a cross-sectional configuration example of the flexible tube 13 according to a modified example of the second embodiment. In the first embodiment described above, a configuration in which the gaps S are uniformly provided between the spiral tube 21 and the mesh tube 22 is shown. However, in actuality, the loosely wound portion 21b is easily deformed by an external force, so that a sufficient gap S is not necessarily required. In practice, the densely wound portion 21a is densely aligned in the longitudinal axis direction due to bending. What is necessary is just to provide in the movement range L of the winding part 21a. This movement range L can be obtained by simulation or creation of a prototype.

In this modified example, the mesh tube 22 of the outer layer portion 20 has a gap S2 in the moving range L of the densely wound portion 21a with respect to the spiral tube 21 having the same diameter of the closely wound portion 21a and the loosely wound portion 21b. This is a configuration example in which the inner diameter is increased. Since the inner diameter of the mesh tube 22 is increased, the outer diameter of the outer layer portion 20 is also increased.
According to this modification, by providing a gap between the closely wound portion 21a and the outer layer portion 20, when the flexible tube 13 is bent, the densely wound portion 21a moves due to the bending of the loosely wound portion 21b. However, the spiral tube 21 can reduce the friction to the inner peripheral surface of the mesh tube 22, and the flexible tube 13 can be bent smoothly. Furthermore, even if the inner diameter of the outer layer part 20 is changed, the outer diameter of the outer layer part 20 may be made constant by increasing the thickness of the resin in a portion where the inner diameter is small.

[Third Embodiment]
Next, the structure of the flexible tube 13 according to the third embodiment will be described.
6 is a diagram conceptually showing a cross-sectional configuration of a flexible tube having a gap according to the present embodiment, FIG. 7 is a diagram showing a conceptual configuration of a mesh tube in which coils are knitted, and FIG. FIG. 8B is a view showing a conceptual shape when a flexible tube is bent, and FIG. 8B is a view showing a cross-sectional configuration of a curved portion AA in FIG. 8A. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

In the present embodiment, as shown in FIG. 6, a coil 31 is knitted into the mesh tube 22 of the outer layer portion 20 of the flexible tube 13.
The flexible tube 13 includes a spiral tube 21 having a densely wound portion 21a and a loosely wound portion 21b that are alternately and continuously arranged, a mesh tube 32 that covers the spiral tube 21 and a coil 31 is spirally knitted. The outer tube 23 is formed integrally with the outer peripheral surface of the mesh tube 32. Also in this embodiment, it is covered with a gap S of a predetermined interval between the outer peripheral surface of the spiral tube 21 and the mesh tube 32.

  In the present embodiment, one coil 31 is knitted so as to spirally wind on the outer periphery of the spiral tube 21, but basically, the outer layer 20 can be prevented from being flattened when bent. If it is, it will not specifically limit, You may be knitted in the cross shape of cyclic | annular form, and horizontal and vertical (or crossing mutually diagonally). It is assumed that the knitted coil 31 is fixed to the mesh tube 32.

  By knitting the coil 31 spirally into the mesh tube 32 in this way, the outer layer portion 20 is difficult to flatten when the flexible tube 13 is bent as shown in FIGS. 8A and 8B. For this reason, the gap S provided between the spiral tube 21 and the mesh tube 32 due to flattening is prevented from being unduly narrowed, and an increase in catch and friction is prevented, and the spiral tube 21 moves smoothly in the mesh tube 32.

According to the present embodiment, the closely wound portion 21a of the spiral tube 21 is moved adjacent to the difference in length between the spiral tube 21 and the outer layer portion 20 generated when the flexible tube 13 is bent. It becomes easy to be absorbed by the loosely wound portion 21b. Therefore, it is possible to prevent a large pressure from being applied to the tightly wound portion 21a of the spiral tube 21 and to prevent the occurrence of a shift sound, repulsion and vibration due to the pitch deviation of the strands. Further, by preventing the outer layer portion 20 from being flat, the curved portion can be formed into a smooth arc shape. Moreover, the flat wrinkles which arise when a flat part is repeatedly performed in the same location with respect to the outer layer part 20, and what is called deformation | transformation in radial direction can also be prevented.
Furthermore, since the outer layer portion 20 is not easily flattened, the gap provided between the spiral tube 21 and the mesh tube 32 can be minimized, thereby making the flexible tube 13 thinner.

A modification of the coil 31 that can be applied to the present embodiment will be described. FIG. 9 is a diagram showing modifications (a) to (f) of the cross section of the coil 31.
In FIG. 9, the cross section of the coil 31 includes (a) a circle 31a, (b) an ellipse 31b, (c) an oval (track) shape 31c, (d) a rectangular shape 31d, (e) a saddle shape 31e, and (f ) A semicircular shape 31f or the like can be applied. These are made of a highly elastic wire. Here, a solid (solid) structure coil is mentioned, but the same effect can be obtained even if an air (pipe) structure coil is used. In terms of weight reduction, an air structure is preferable. In the present embodiment, one coil is taken as an example, but the coil may be formed of a wire in which a plurality of thin wire rods are wound.

[First Modification of Third Embodiment]
Next, a first modification of the third embodiment will be described.
FIG. 10 is a diagram illustrating a configuration example in which a coil is incorporated in the outer skin portion 33 of the flexible tube 13 as a first modification. In this modification, the same reference numerals are given to the same components as those in the third embodiment described above, and detailed description thereof will be omitted.
In this modification, the coil 31 is spirally embedded in the outer skin portion 33 made of a resin tube of the outer layer portion 20 as described above.

  This modification can obtain the same operational effects as those of the third embodiment. Furthermore, since the coil 31 is embedded in the outer skin portion 33 at the time of manufacturing, the manufacturing operation is easier than the case where the coiled tube 22 is knitted, and the number of man-hours is reduced. In the present embodiment, an example in which one coil is embedded has been described. However, a wire is formed of a material having high elasticity and conductivity, and the inside of the outer skin portion 33 having insulating properties is arranged in parallel in a plurality of rows. It can be used as a signal line (for example, a sensor signal or the like) by being spirally wound.

[Second Modification of Third Embodiment]
Next, a second modification of the third embodiment will be described.
FIG. 11 is a diagram showing a configuration example in which the coil 31 is arranged on the inner peripheral surface of the mesh tube 22 as a second modification. In this modification, the same reference numerals are given to the same components as those of the second embodiment described above, and detailed description thereof will be omitted.

  In this modification, a coil resin layer 34 including a spiral coil 31 is disposed on the inner peripheral surface of the mesh tube 22. The coil resin layer 34 is formed when the outer layer portion 20 is formed, and is configured integrally with the outer layer portion 20. In this modification, the coil resin layer 34 has a flat inner surface as a layer, but may be formed in a bowl shape covering the arc in the cross-sectional direction of the coil.

  Although not shown, the spiral coil 31 may be provided directly on the inner peripheral surface of the mesh tube 22 without a resin layer. In this case, any of the coils 31 in the cross-sectional shape shown in FIG. 6 may be used. However, the coil 31 has a bonding plane such as a saddle shape 31e and a semicircular shape 31f, and has a point (on the circumference) on the spiral tube 21. A shape having a low coefficient of friction by contacting with a line is preferable. According to this modification, it has the same effect as the first modification of the third embodiment described above.

[Fourth Embodiment]
A fourth embodiment will be described.
In the present embodiment, for example, a layer that reduces surface friction such as a fluororesin coat is formed on the outer peripheral surface of the spiral tube 21 and / or the inner peripheral surface of the mesh tube 22 shown in FIG. Alternatively, a layer that has been subjected to a treatment for increasing the friction coefficient by a rough surface treatment or the like is formed. That is, a process of partially changing the surface friction coefficient (friction force) is performed on the spiral tube 21 and the mesh tube 22.
If the friction coefficient between the spiral tube 21 and the mesh tube 22 is increased by this process, the hardness against bending is increased. Conversely, if the friction coefficient is decreased, the friction coefficient is decreased.

  That is, the hardness against bending can be changed by changing the friction coefficient between the spiral tube 21 and the mesh tube 22 in the longitudinal axis direction of the flexible tube 13. Therefore, the hardness against bending of the flexible tube 13 can be changed regardless of the hardness of the outer layer portion 20. For example, the insertion property is improved by hardening the proximal end side and softening the distal end side.

  According to the present invention, there is provided a flexible tube having a spiral tube in which a densely wound portion and a loosely wound portion are combined, and can be bent smoothly without any sense of incongruity when bent, and an endoscope using the flexible tube. Can be provided.

The flexible tube according to the embodiment according to the present invention includes a densely wound portion having a portion in which a plate-like strand is wound spirally and stretched along the longitudinal axis direction, and the adjacent strands are in close contact with each other. A spiral tube having a sparsely wound portion in which the adjacent strands are separated from each other, and a cylindrical shape that covers the natural length of the spiral tube, and has a larger inner diameter than the outer diameter of the spiral tube An outer layer portion, and a dimension of a first gap generated by a difference between an outer diameter of the loosely wound portion and an inner diameter of the outer layer portion in the spiral tube while the spiral tube is in a straight state to a maximum curved state. the diameter of the close coiled portion and the second diameter and the outer portion of the spiral tube to size increase of the gap caused by the difference between the outer peripheral surface and the inner diameter of the outer portion of the said spiral tube is set .

Claims (10)

A plate-like wire is spirally wound and stretched along the longitudinal axis direction, and a densely wound portion having a portion where the adjacent strands are in close contact with each other, and a sparse separation where the adjacent strands are separated from each other A spiral tube having a winding portion;
It has a cylindrical shape covering the helical tube of natural length, and comprises an outer layer portion having an inner diameter larger than the outer diameter of the helical tube,
Due to the gap due to the difference between the outer diameter of the spiral tube and the inner diameter of the outer layer portion, the outer tube portion of the outer layer portion that contacts the outer peripheral surface in the radial direction of the spiral tube during the period from the straight state to the maximum curved state. A flexible tube characterized in that the diameter of the spiral tube and the diameter of the outer layer portion are set so that a portion that is not in contact with the inner peripheral surface remains.   Between the outer layer portion and the spiral tube, there is a gap between the outer peripheral surface of the spiral tube and the inner peripheral surface of the outer layer portion at least until the flexible tube is bent from a straight state to a bent state. The flexible tube according to claim 1.   The outer layer portion is disposed on the inner side facing the outer peripheral surface of the spiral tube, and has a net-like tube formed by weaving linear strands into a tubular shape and extending along the longitudinal axis direction. Item 2. The flexible tube according to Item 1.   The flexible tube has a difference in length between the spiral tube and the outer layer portion that occurs when the flexible tube is bent, because the densely wound portion of the spiral tube is partially moved in a non-contact manner due to a gap with the outer layer portion. The flexible tube according to claim 1, wherein the flexible tube is absorbed by the adjacent sparsely wound portions.   2. The flexible tube according to claim 1, wherein an outer diameter of the spiral tube is changed depending on a position in a longitudinal axis direction, and a size of the gap between the inner peripheral surface of the outer layer portion is changed. .   2. The flexible tube according to claim 1, wherein an inner diameter of the outer layer portion is changed depending on a position in the longitudinal axis direction to change a size of the gap between the outer peripheral surface of the spiral tube.   The size of the gap generated by the difference between the inner diameter of the outer layer portion and the outer diameter of the spiral tube is greater than the difference between the outer peripheral surface of the loosely wound portion and the inner diameter of the outer layer portion of the spiral tube. The flexible tube according to claim 1, wherein the flexible tube is set so that a difference between an outer peripheral surface of the tightly wound portion and an inner diameter of the outer layer portion is increased.   2. The flexible tube according to claim 1, wherein the gap is provided over the entire length of a portion of the spiral tube in which the densely wound portion and the loosely wound portion are alternately provided from the tip.   In the outer layer portion, a second spiral tube is integrally provided which is formed of an elastic member which is wound in a spiral shape with a linear wire and extends along the longitudinal axis direction. The flexible tube according to claim 1.   An endoscope having the flexible tube according to claim 1.

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