JP7145663B2 - insertion device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an insertion device having a coil pipe arranged in an insertion portion to be inserted into a subject, formed by winding a wire, and through which a traction member is inserted.

2. Description of the Related Art In recent years, an insertion device that is inserted into a subject, such as an endoscope, has been widely used in the medical and industrial fields. 2. Description of the Related Art An endoscope can perform observation, treatment, and the like of a site to be examined in a subject by inserting an elongated insertion portion into the subject.

Here, it is well known that the insertion portion of the endoscope is provided with a bending portion that can be bent in a plurality of directions, for example.

The bending portion improves the progressability of the insertion portion at the bend in the duct, and is connected to the distal end of the insertion portion in the longitudinal direction of the bending portion (hereinafter simply referred to as the distal end). The observation direction of the observation optical system provided in the is variable.

Normally, the bending portion is configured to be freely bendable in four directions, for example, up, down, left, and right, or in two directions, up, down, left, and right, by connecting a plurality of bending pieces along the longitudinal axis of the insertion portion.

Specifically, when the bending portion is bent in four directions, four wires are inserted in the insertion portion so as to be freely movable back and forth in the longitudinal direction. The tip of each wire is fixed to the bending piece positioned closest to the tip side in the longitudinal axis direction (hereinafter simply referred to as the tip side) among the plurality of bending pieces. By pulling one of the four wires using a knob or the like provided on the operating portion, the bending portion can be bent in any direction up, down, left, or right.

In the insertion section, a flexible tube elongated in the longitudinal direction is connected to the proximal end (hereinafter simply referred to as the proximal end) of the bending section in the longitudinal axis direction.

Furthermore, a configuration is known in which four coil pipes in which strands of wire are helically and tightly wound along the longitudinal axis are provided in a flexible tube. A wire is passed through each coil pipe, and the distal end of each coil pipe is fixed to the distal end of the flexible tube, and the proximal end is fixed in the operating portion.

Each coil pipe has a function of guiding each wire so as to be freely movable along the axial direction of the coil pipe without being displaced in the radial and circumferential directions of the flexible tube.

Furthermore, when the bending portion of each coil pipe is bent due to the pulling of each wire, the distal end and the base end of each coil pipe are fixed so that they are compressed in the axial direction. It has a function to prevent it from being curved together.

Here, the coil pipe is generally formed by winding a wire having a circular cross section along the axial direction to a length extending from the tip of the flexible tube to the inside of the operating portion. .

If the wire has a circular cross section, the inner peripheral surface of the coil pipe has a curved shape after winding. There is an advantage that the sliding resistance is reduced and the amount of pulling operation force for the wire is reduced.

However, if the wire has a circular cross section, not only does the outer diameter of the coil pipe increase, but the curved surfaces of the wires come into contact with each other at the contact portions in the axial direction.

For this reason, when the flexible tube meanders, so-called pitch deviation occurs, in which one element wire is shifted in a direction different from the axial direction at the contact portion with respect to the other element wire, and the durability of the coil pipe is reduced. There was a problem that the quality was lowered.

In view of such problems, in Patent Document 1, after winding, the outer diameter of the coil pipe is reduced, and the strands of wire are arranged such that the pitch deviation is less likely to occur at each contact portion between the strands along the axial direction. is disclosed. Specifically, the cross-sections of the wires that are adjacent in the axial direction are formed in a cannonball shape so that the curved surface formed on the other wire is in contact with the flat surface formed on one wire. A coil pipe configuration is disclosed.

JP 2015-104388 A

By the way, when the wire is pulled and the coil pipe is compressed in the axial direction, a torsional moment is applied to the wire and a rotational force is applied. It is also given to the contact portion between the lines.

Therefore, when the cross section of the wire is circular and the curved surfaces of the wire are in contact at the contact portion, or when the cross section of the wire disclosed in Patent Document 1 is formed in a bullet shape and the contact portion is one-sided When the curved surface of the other wire is in contact with the flat surface of the other wire, if a rotational force is applied to the contact portion, the contact area at the contact portion is small, so pitch deviation will also occur. There was a problem.

The above problem is not limited to endoscopes, and is the same for other insertion devices such as treatment instruments having wires and coil pipes in flexible tubes.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an insertion device having a configuration in which pitch deviation is unlikely to occur at the contact portions of the wires even when a compressive force is applied to the coil pipe in the axial direction. intended to provide

In order to achieve the above object, an insertion device according to one aspect of the present invention includes an insertion section to be inserted into a subject, a traction member arranged in the insertion section, and a wire wound around the insertion section arranged in the insertion section. and a coil pipe into which the traction member is inserted, wherein the cross section of the strands along the axial direction of the coil pipe is the same as that of the strands adjacent to each other in the axial direction. connects a contact portion, a curved surface portion located on the inner peripheral surface of the coil pipe, and the contact portion and the curved surface portion, and has a curvature radius different from the curvature radius of the curved surface portion and a first connecting portion formed in a curved shape, and all of the contact portions are formed in a planar shape.

ADVANTAGE OF THE INVENTION According to this invention, even if compressive force is applied to a coil pipe in the axial direction, it is possible to provide an insertion device having a configuration in which the contact portions of the wires are unlikely to shift in pitch.

The figure which shows the external appearance of the endoscope of 1st Embodiment. Partial cross-sectional view of the insertion part along line II-II in Fig. 1 Partial cross-sectional view along the longitudinal axis of the coil pipe and wire along line III-III in FIG. 4 is a partial cross-sectional view along the axial direction showing a state in which the wire is pulled and pulled into the coil pipe when the coil pipe in FIG. 3 is bent; FIG. 3 and a conventional circular wire cross section are compared roughly 4 is a partial cross-sectional view along the axial direction of the coil pipe, showing a modified example in which the distal side connecting portion and the base end side connecting portion have different curvature radii in the first connecting portion of FIG. 3 ; FIG. FIG. 5 is a partial cross-sectional view along the axial direction of a coil pipe and a wire provided in the insertion section of the endoscope showing the second embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, an endoscope will be used as an example of the insertion device.

(First embodiment)

FIG. 1 is a diagram showing the appearance of an endoscope according to this embodiment.

As shown in FIG. 1, an endoscope 1 includes an insertion portion 2 to be inserted into a subject, an operation portion 3 connected to a proximal end of the insertion portion 2, and a A main part is constituted by a universal cord 8 and a connector 9 provided at the extending end of the universal cord 8 . Note that the endoscope 1 is electrically connected to external devices such as a control device and a lighting device via the connector 9 .

The insertion portion 2 includes a long flexible tube 2k extending along the longitudinal axis direction N of the insertion portion 2 and a bending portion 2w connected to the distal end of the flexible tube 2k. , and a distal end portion 2s connected to the distal end of the curved portion 2w.

An imaging unit (not shown) for imaging the inside of the subject, an illumination unit (not shown) for supplying illumination light to the inside of the subject, and the like are provided in the distal end portion 2s.

The bending portion 2 w can be bent in four directions, for example, up, down, left, and right by bending operation knobs 4 and 6 provided on the operation portion 3 .

Specifically, the operation portion 3 is provided with a bending operation knob 4 for bending the bending portion 2w in the vertical direction and a bending operation knob 6 for bending the bending portion 2w in the horizontal direction.

In addition, by rotating together with the bending operation knob 4 into the operation portion 3, wires 10u and 10d (see FIG. 2), which are inserted into the insertion portion 2 and the operation portion 3 and will be described later, are pulled and loosened, thereby bending. A vertical bending pulley (not shown) is provided for bending the portion 2w in the vertical direction.

Further, wires 10r and 10l (see FIG. 2, wire 10r is not shown), which are inserted into the insertion portion 2 and the operation portion 3, are inserted into the operation portion 3 by rotating together with the bending operation knob 6. A left-right bending pulley is provided for bending the bending portion 2w in the left-right direction by pulling and loosening.

Since the configurations of the pulley for vertical bending and the pulley for horizontal bending are well known, a detailed description using the drawings will be omitted.

Further, the operation portion 3 is provided with a fixed lever 5 for fixing the rotational position of the bending operation knob 4 and a fixed knob 7 for fixing the rotational position of the bending operation knob 6 .

Next, the configuration of the main part related to the present embodiment on the distal end side of the insertion portion shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a partial cross-sectional view of the insertion portion taken along line II-II in FIG.

As shown in FIG. 2, a plurality of cylindrical bending pieces 11 are connected along the longitudinal axis direction N inside the bending portion 2w. The plurality of bending pieces 11 are rotatably connected to pieces adjacent to each other in the longitudinal axis direction N by rivets 12 so as to be freely bendable in the four directions of up, down, left, and right.

The outer circumferences of the plurality of bending pieces 11 are covered with blades 16 , and the outer circumferences of the blades 16 are covered with bending rubber 17 .

Inside the insertion portion 2 and the operation portion 3, there are, for example, four wires 10r, 10l, 10u, 10d (wire 10r is not shown) are inserted into the insertion portion 2 with a displacement of approximately 90° in the circumferential direction.

The tip of each of the wires 10r to 10d is fixed to the bending piece 11a positioned most on the tip side among the plurality of bending pieces 11 provided in the bending portion 2w.

Further, tubular guides 15r, 15l, 15u, 15d ( A plurality of guides 15r are fixed to the inner peripheral surface of each bending piece 11. The guides 15r are not shown.

Specifically, the guides 15r to 15d are also fixed at intervals of approximately 90° in the circumferential direction. Wires 10u are inserted through the guides 15u, and wires 10d are inserted through the guides 15d.

The proximal ends of the two vertical bending wires 10u and 10d are wound around the vertical bending pulleys described above, and the proximal ends of the horizontal bending wires 10r and 10l are respectively wound on the horizontal bending pulleys. It is wound around a bending pulley.

That is, when the bending operation knob 4 is operated, one of the two vertical bending wires 10u and 10d is moved backward N2 and the other is moved forward N1 by the vertical bending pulley. is pulled and the other is relaxed, the bending portion 2w bends in either the up or down direction.

When the bending operation knob 6 is operated, one of the two left and right wires 10r and 10l is moved backward N2 and the other is moved forward N1 by the left and right bending pulleys. is pulled and the other is relaxed, the bending portion 2w bends in either the left or right direction.

In addition, the distal end side of the connecting member 18 is fixed to the inner periphery of the bending piece 11z positioned closest to the proximal side of the bending pieces 11, and the inner periphery of the proximal end side of the connecting member 18 is provided with a flexible The tip end side of the blade that constitutes the tube 2k is fixed.

The blade is composed of, for example, a helical tube 25 made of metal and a reticular tube 26 covering the outer periphery of the helical tube 25. The outer periphery of the reticular tube 26 is covered with a skin tube 27. ing.

In addition, on the outer periphery of each of the four wires 10r to 10d inserted in the flexible tube 2k, for example, flexible coil pipes 20r, 20l, 20u, 20d (coil pipes 20r (not shown) are coated respectively.

That is, in the flexible tube 2k, four coil pipes 20r to 20d are inserted at positions shifted from each other by approximately 90° in the circumferential direction of the flexible tube 2k.

Further, the ends of the coil pipes 20r to 20d are respectively fixed to the ends of the flexible tube 2k, specifically to the connecting member 18 by brazing, for example. Furthermore, proximal ends of the respective coil pipes 20r to 20d are fixed within the operating portion 3. As shown in FIG.

Each of the coil pipes 20r to 20d is compressed in the longitudinal direction N due to the fixed distal and proximal ends when the bending portion 2w is bent as the wires 10r to 10d are pulled. It has a function to prevent even the flexible tube 2k from bending together with the bending portion 2w.

The coil pipes 20r to 20d are formed of coils in which, for example, stainless steel wires 50 (see FIG. 3), which are flexible materials, are densely wound along the longitudinal axis direction N. As shown in FIG.

The reason why the coil pipes 20r to 20d are made of flexible coils is that if the outer circumference of each wire 10r to 10d is covered with a hard pipe made of metal, the flexibility of the flexible tube 2k is reduced. This is because

Therefore, each of the coil pipes 20r to 20d does not reduce the flexibility of the flexible tube 2k, and when the bending portion 2w is bent, a compressive force acts along the axial direction W of each of the coil pipes 20r to 20d. As long as it can withstand the stress, it may be composed of components other than the coil. The axial direction W of each of the coil pipes 20r to 20d in an unbent state substantially coincides with the longitudinal axis direction N. As shown in FIG.

Next, wire shapes of the coil pipes 20r to 20d will be described with reference to FIGS. 3 to 5. FIG.

3 is a partial cross-sectional view along the axial direction of the coil pipe and wire along line III-III in FIG. FIG. 5 is a partial cross-sectional view along the axial direction showing a state in which the wire is drawn into the pipe, and FIG. 5 is a diagram schematically comparing the wire cross-section of FIG.

The wires 10r to 10d and the coil pipes 20r to 20d are hereinafter referred to as the wires 10 and the coil pipes 20 in order to simply describe the wire shapes of the wires 10r to 10d and the coil pipes 20r to 20d. That is, the wire 10 and the coil pipe 20 indicate the configuration of the wires 10r to 10d and the coil pipes 20r to 20d.

Further, since the cross-sectional shapes of the wires 50 shown below are all cross-sectional shapes along the axial direction W, the description of the cross-sectional direction is omitted.

As shown in FIGS. 3 and 4, the coil pipe 20 has a wire 50 spirally wound along the axial direction W. As shown in FIGS. In order to reduce the diameter of the coil pipe 20, the wire 50 is substantially perpendicular to the axial direction W and has a diameter H along the radial direction K of, for example, 0.3 mm or less.

The wires 50 are configured so that the wires 50 adjacent to each other in the axial direction W can contact each other, and the contact portion 52 between the wires 50 is substantially orthogonal to the axial direction W and is flat along the radial direction K, for example. It has a contoured shape.

Each strand 50 after being wound has a cross-sectional shape having a curved surface portion 51 and a first connecting portion 53 .

The curved surface portion 51 is positioned to be the inner peripheral surface 20n of the coil pipe 20 and has a radius of curvature R10.

The first connecting portion 53 connects between the contact portion 52 and the curved surface portion 51, and is formed in a curved shape having a curvature radius R11 (R10≠R11) different from the curvature radius R10.

The first connecting portion 53 is formed on the distal end side connecting portion 53a formed on the distal end side of each wire 50 after winding, and on the proximal end side in the axial direction W (hereinafter simply referred to as the proximal end side). and the base end side connecting portion 53b.

Next, the operation and effects of this embodiment will be described.

When one of the bending operation knobs 4 and 6 is operated to pull the wire 10, the bending portion 2w is bent in any one of up, down, left, and right directions. In actual use, the wire is pulled while the coil pipe is bent, resulting in the state shown in FIG.

At this time, as described above, the curved surface portion 51 of each wire 50 after winding is positioned on the inner peripheral surface 20n of the coil pipe 20 . Therefore, the contact area of the wire 50 with respect to the wire 10 is smaller than in the conventional configuration in which the wire 50 has a cannonball-shaped cross section and the planar portion is positioned on the inner peripheral surface 20n.

Frictional force F is usually defined as friction coefficient μ×normal force N (F=μN), but naturally the frictional force F increases as the contact area between the wire 50 and the wire 10 increases.

In addition, when the coil pipe 20 is curved, the wire 10 tries to slide the shortest distance in the coil pipe 20, so that the wire 10 strongly bites into the inner peripheral surface 20n of the coil pipe 20 that is curved. It slides while contacting the inner peripheral surface 20n.

Therefore, when the wire 10 slides, the wire 10 and the inner peripheral surface 20n of the coil pipe 20, which are both made of metal, are scraped away from each other. It becomes a large resistance when sliding.

Therefore, in the present embodiment, since the curved surface portion 51 of the wire 50 is positioned on the inner peripheral surface 20n, the wire 10 is more likely to be bent than the case where the flat portion is positioned on the inner peripheral surface 20n. The contact area with respect to the coil pipe 20 is reduced, and the sliding resistance of the wire 10 within the coil pipe 20 is reduced. Therefore, since the amount of pulling operation force for the wire 10 is smaller than that in the conventional art, it is possible to improve the bending operability of the operator.

Furthermore, since the amount of the wire 10 and the coil pipe 20 that is scraped off is reduced, the wear of the wire 10 and the coil pipe 20 is reduced. can be reduced.

Further, when a compressive force P is applied to the coil pipe 20 along the axial direction W, a torsional moment M is generated in each wound wire 50 and a rotational force is applied to the contact portion 52 . , the above-described pitch deviation occurs.

However, in the present embodiment, the wires 50 have a cross-sectional shape along the axial direction W in which the contact portions 52 between the wires 50 adjacent to each other in the axial direction W are formed flat. That is, the flat surfaces are in contact with each other at the contact portion 52 . As a result, the contact area between the wires 50 at the contact portion 52 becomes larger than in the conventional case where the cross section of the wires 50 is circular or cannonball-shaped, as described above.

Therefore, the frictional force between the wires 50 at the contact portion 52 becomes larger than in the conventional case, and the shape of the wires 50 tries to suppress the rotational force applied to the contact portion 52, so that the contact portion Even if the torsional moment M is applied to 52, pitch deviation is unlikely to occur.

Furthermore, if the cross-sectional shape is such that the curved surface portion 51 and the flat contact portion 52 are connected, a corner portion is normally generated at the connection portion, and the wire 10 sliding while biting into the inner peripheral surface 20n is not easily bent. There was a possibility that it would get caught on the corners and reduce the slidability.

However, in the present embodiment, the wire 50 has a cross-sectional shape having a first connecting portion 53 having a curved surface shape between the curved surface portion 51 and the contact portion 52 . As a result, since corners are not generated, the wire 10 can be smoothly slidable.

Furthermore, when the coil pipe 20 is bent, the corners do not come into contact with each other, so the coil pipe 20 can be easily bent with a large bending angle.

In addition, in the above-described cross-sectional shape of the wire 50 in the present embodiment, as compared with the conventional circular cross-sectional shape, the wire 50 is crushed in the radial direction K, so that the diameter is reduced as shown in FIG. The magnitude in direction K decreases (Ka<Kb).

As a result, the outer diameter of the coil pipe 20 can be reduced. Therefore, it is possible to reduce the filling rate of the internals of the flexible tube 2k in which the coil pipe 20 is provided.

Here, when the bending portion 2w is bent, the internal objects move in the axial direction W within the flexible tube 2k. Since there is little contact and the built-in objects can move smoothly, the bending operation is not hindered.

Furthermore, since the outer diameter of the coil pipe 20 can be made smaller, a surplus space is generated in the flexible tube 2k, and new functions can be installed in the space.

Further, as shown in FIG. 5, when the wire 50 is crushed in the radial direction K so that the outer diameter of the coil pipe 20 is reduced, the wire 50 becomes longer in the axial direction W than in the conventional case (Na>Nb).

As a result, the number of turns of the wire 50 can be reduced. Therefore, since the contact area of the wire 10 with respect to each wound element wire 50 can be reduced compared to the conventional art, the sliding resistance of the wire 10 can be reduced.

As described above, it is possible to provide the endoscope 1 having a configuration in which the contact portions 52 between the wires 50 are unlikely to shift in pitch even when the compressive force P is applied to the coil pipe 20 in the axial direction W. .

A modified example is shown below with reference to FIG. FIG. 6 is a partial cross-sectional view along the axial direction of the coil pipe showing a modification in which the radius of curvature of the distal side connecting portion and the proximal side connecting portion of the first connecting portion of FIG. 3 are different.

In the above-described embodiment, the first connecting portion 53 is formed to have a curvature radius R11 different from the curvature radius R10 of the curved surface portion 51 .

In addition, as shown in FIG. 6, the first connecting portion 53 may be formed so that the radius of curvature R1 of the connecting portion 53a on the distal side is larger than the radius of curvature R2 of the connecting portion 53b on the proximal side ( R1>R2).

According to this, when the wire 10 is pulled when bending the bending portion 2w, that is, when the wire 10 is pulled into the coil pipe 20 from the tip of the coil pipe 20 from the front N1 to the rear N2, the wire 10 can be more effectively prevented from being caught on the distal end side connecting portion 53a than in the present embodiment described above.

That is, the slidability of the wire 10 can be improved more than that of the present embodiment described above. Other effects are the same as those of the present embodiment described above.

(Second embodiment)

FIG. 7 is a partial cross-sectional view along the axial direction of the coil pipe and wire provided in the insertion section of the endoscope showing this embodiment.

The configuration of the endoscope according to the second embodiment is different from that of the endoscope according to the first embodiment shown in FIGS. is formed in a plane. Therefore, only this difference will be described, and the same reference numerals will be given to the same configurations as in the first embodiment, and the description thereof will be omitted.

Each wire 50 wound on the coil pipe 20 in the endoscope of the present embodiment shown in FIG. It has a cross-sectional shape with a portion 54 .

Further, the wire 50 has a cross-sectional shape along the axial direction W, which connects between the flat portion 54 and the contact portion 52 and has a second connecting portion 55 formed in a curved shape.

Other configurations are the same as those of the first embodiment described above.

According to such a configuration, since the flat portion 54 is formed on the outer peripheral surface 20g, the height of the wire 50 in the radial direction K can be reduced compared to the first embodiment (Kc< Ka).

Therefore, since the filling rate in the flexible tube 2k becomes low, the advance and retreat of the internal objects of the flexible tube becomes smooth, and the contact between the internal objects is reduced, which hinders the bending operation. There is no Furthermore, since the contact between the coil pipe 20 and the built-in components is reduced, the durability of these members can be improved.

Furthermore, since the second connecting portion 55 eliminates the corners on the outer peripheral surface 20g side, contact between the coil pipe 20 and other built-in components can be further reduced, thereby improving the durability of these members. can be done.

Furthermore, since the outer diameter of the coil pipe 20 can be made smaller, a surplus space is generated in the flexible tube 2k, and new functions can be installed in the space.

Further, when the coil pipe 20 is bent, the corners described above do not come into contact with each other, so that the coil pipe 20 can be easily bent with a large bending angle.

Other effects are the same as those of the first embodiment described above.

In addition, in the first and second embodiments described above, the surface roughness of the contact portion 52 may be formed to be rougher than the surface roughness of the curved surface portion 51 .

As a result, the resistance between the wire 10 and the wire 10 is reduced at the curved surface portion 51, so that the slidability of the wire 10 is improved. less likely to occur.

Other effects are the same as those of the above-described first and second embodiments.

Further, in the above-described first and second embodiments, the contact portion 52 is formed in a planar shape substantially perpendicular to the axial direction W and along the radial direction K. Needless to say, it may be formed along a direction other than the direction substantially orthogonal to the axial direction W as long as it is formed in a planar shape.

Furthermore, in the first and second embodiments described above, the endoscope 1 was used as an example of the insertion device. Needless to say, the present invention can also be applied to a therapeutic instrument or the like having a coil pipe and a wire in a flexible tube, and having a grasping portion actuated by pulling the wire.

1... Endoscope (insertion device)
2... Insertion portion 10... Wire (traction member)
DESCRIPTION OF SYMBOLS 20... Coil pipe 20g... Outer peripheral surface 20n... Inner peripheral surface 50... Wire 51... Curved surface part 52... Contact part 53... 1st connection part 53a... Tip side connection part 53b... Base end side connection part 54... Flat part 55... Second connecting portion W: Axial direction R1: Curvature radius of the distal end side connecting portion R2: Curvature radius of the base end side connecting portion R10: Curvature radius of the curved surface portion R11: Curvature radius of the first connecting portion

Claims (5)

an insertion section inserted into a subject;
a traction member disposed within the insert;
a coil pipe disposed in the insertion portion and formed by winding a wire, through which the traction member is inserted;
and
A cross section of the wire along the axial direction of the coil pipe is
a contact portion where the axially adjacent strands contact each other ;
a curved surface portion located on the inner peripheral surface of the coil pipe;
a first connecting portion that connects between the contact portion and the curved surface portion and is formed in a curved surface shape with a curvature radius different from the curvature radius of the curved surface portion;
, wherein all of the contact portions are planar. The first connecting part is
a distal end side connecting portion formed on the distal end side of the insertion portion in the cross section of the wire;
a base end side connecting portion formed on the base end side of the insertion portion in the cross section of the wire;
has
2. The insertion device according to claim 1, wherein the radius of curvature of the distal connecting portion is larger than the radius of curvature of the proximal connecting portion. 3. The insertion device according to claim 1, wherein the cross section of the wire has a flat portion located on the outer peripheral surface of the coil pipe and along the axial direction. 4. The insertion device according to claim 3, wherein the cross section of the wire has a second connecting portion that connects between the contact portion and the flat portion and is formed in a curved shape. 3. The insertion device according to claim 1, wherein the surface roughness of the contact portion is formed to be rougher than the surface roughness of the curved surface portion.

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