JP2008104733A - Bending section of endoscope and endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bending section of an endoscope of which the assembling cost or the manufacturing cost is prevented from increasing, and in which the amount of turning of the distal end side or the proximal end side can be easily changed. <P>SOLUTION: The bending section 34 of the endoscope includes: a bending tube 42 having a plurality of joint pieces 44 connected in a turnable state with each other; and an outer jacket 46 covering the outer circumference of the bending tube 42. The outer jacket 46 includes a plurality of projected parts 46a for controlling the bent shape of the bending tube 42, in a projected state from the inner circumferential surface of the outer jacket along the longitudinal direction of the bending section 34 when the outer jacket covers the bending tube 42. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an endoscope bending portion and an endoscope which are provided on the distal end side of an insertion portion of an endoscope and direct the distal end of the insertion portion in a desired direction.

  In order to secure an observation field of view within a narrow lumen, the bending portion of the endoscope is preferably not bent at a constant curvature but bent more rapidly than the proximal end. For this reason, in the conventional bending portion using the joint piece connecting structure used for the bending portion, a plurality of types of joint pieces are used such that the distal end side has a larger amount of rotation than the proximal end side, or separate to the bending portion. By adding this member, the curvature of the curved portion can be bent more rapidly at the distal end side than at the proximal end side.

For example, in the bending portion of the endoscope disclosed in Patent Document 1, the distal end side is bent more rapidly than the proximal end side by filling a rigid member as a separate member on the proximal end side of the bending portion. Can do.
Japanese Patent Publication No.8-17766

  However, when a plurality of types of joint pieces are used, it is necessary to set the connection order of the joint pieces correctly, so that the component cost and the manufacturing cost due to assembly increase. Further, as disclosed in Patent Document 1, if the hardened member is filled on the base end side of the curved portion, the labor for filling and the cost of the member to be filled increase, so that the manufacturing cost increases. That is, an increase in cost such as an increase in the number of parts compared to the case of a curved part having a constant curvature, as well as an increase in part cost and manufacturing cost.

  The present invention has been made to solve such problems, and the object of the present invention is to prevent an increase in costs such as component costs and manufacturing costs, and to rotate the distal end side and the proximal end side. It is an object of the present invention to provide an endoscope bending portion and an endoscope which can be easily changed.

In order to solve the above problems, a bending portion of an endoscope according to the present invention includes a bending tube having a plurality of joint pieces connected to each other so as to be rotatable with respect to each other, and an outer skin that covers an outer periphery of the bending tube. And. The outer skin has a plurality of protrusions that control the bending shape of the bending tube along the longitudinal direction of the bending portion so as to protrude from the inner peripheral surface when the bending tube is covered. It is characterized by being formed.
By forming the protruding portion on the inner peripheral surface of the outer skin, it is possible to appropriately set a portion that is easily bent and a portion that is difficult to be bent along the longitudinal direction of the bending portion. By disposing the outer skin having such a protruding portion on the bending portion, it is possible to realize a desired bending shape in the bending portion with a simple configuration without newly adding parts to the bending portion.

In addition, the width of the protruding portion along the longitudinal direction of the bending portion of the protruding portion is formed so that the distal end side of the bending portion is smaller than the proximal end side of the bending portion. Is preferred.
On the distal end side where the width of the protruding portion is small, the amount of rotation of the joint piece of the same shape can be made larger than the amount of rotation of the joint piece on the proximal end side where the width of the protruding portion is large. For this reason, the curvature degree can be made larger at the distal end side than at the proximal end side. For this reason, the observation visual field by the observation optical system of an endoscope can be taken large.

In addition, at least some of the joint pieces have the same shape, and the protrusion is disposed between the joint pieces of the same shape, and the joint pieces of the same shape rotate with respect to each other. It is preferable to have a height that is sandwiched between the end face of one joint piece and the end face of the other joint piece adjacent to the end side of the one joint piece when moved.
By disposing the protrusions between joint pieces of the same shape, the amount of rotation between the joint pieces can be limited. Therefore, it is possible to appropriately set a portion that is easily bent and a portion that is difficult to be bent along the longitudinal direction of the bending portion. Moreover, since the joint piece of the same shape can be used for the bending portion, the bending portion can be formed at a lower cost.

Further, it is preferable that the protrusion has a substantially corrugated longitudinal cross section.
If the pitch corresponding to the wavelength or half-wavelength of the outer skin of the outer skin is reduced, the outer skin can be easily bent, and if the pitch is increased, the outer skin can be hardly bent. For this reason, the curve degree of a bending part is controllable with the outer skin which has a protrusion part whose longitudinal section is a waveform substantially on an internal peripheral surface.

In order to solve the above problems, an endoscope according to the present invention includes an elongated insertion portion having a bending portion on the distal end side that is bent by an operation by the operation portion. The bending portion includes a bending tube in which a plurality of joint pieces are connected to be rotatable along the axial direction of the insertion portion, and a cylindrical outer cover that covers an outer periphery of the bending tube. Has a plurality of protrusions for controlling the amount of rotation of the joint piece on the inner side along the longitudinal direction of the bending portion.
By restricting the amount of rotation of each joint piece by forming a protrusion that can be set appropriately on the inner peripheral surface of the outer skin and a portion that is difficult to bend, without adding new parts to the bending portion The desired curved shape of the bending portion can be realized with a simple configuration.

In addition, it is preferable that the protruding portion is formed such that a width in a direction along a longitudinal direction of the bending portion is smaller on a distal end side of the bending portion than on a proximal end side of the bending portion.
Of the projecting portions, the distal end side of the outer skin having a smaller width in the direction along the longitudinal direction of the curved portion is easier to bend than the proximal end side. For this reason, it is possible to provide an endoscope in which the distal end side of the bending portion is improved in degree of bending as compared to the proximal end side.

In addition, at least some of the joint pieces have the same shape, and the protrusion has a state in which at least a part of the protrusion has a step difference in a convex state with respect to the inner peripheral surface of the outer skin. It is suitable that it is formed.
When the joint piece is rotated by disposing the protrusions protruding so as to have a step in a convex state with respect to the inner peripheral surface of the outer skin, the end of the joint piece when the joint piece is rotated Thus, the rotation of the joint pieces can be restricted when they come into contact with the protrusion (when the protrusion is held). In other words, the degree of bending of the bending portion can be set by defining the width of the protruding portion. In other words, the amount of rotation between the joint pieces can be increased at the portion where the width of the protrusion is reduced, and the amount of rotation between the joint pieces can be reduced at the portion where the width of the protrusion is increased. For this reason, the bending degree of a bending part can be suitably set to a front-end | tip part, a base end part, etc.

Further, it is preferable that the protruding portion is formed smoothly and continuously with respect to the inner peripheral surface of the outer skin.
By setting the pitch of the thin portion of the outer skin, the outer skin is easily bent at a portion where the pitch is small, and the outer skin is difficult to be bent at a portion where the pitch is large. For this reason, the degree of curvature can be set by appropriately setting the ease of bending the outer skin.

  According to the present invention, it is possible to provide an endoscope bending portion and an endoscope that can prevent an increase in costs such as component costs and manufacturing costs, and can easily change the amount of rotation on the distal end side and the proximal end side. Can do.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below with reference to the drawings.
A first embodiment will be described with reference to FIGS.
As shown in FIG. 1, the endoscope 10 includes an elongated insertion portion 12 and an operation portion 14 provided at a proximal end portion of the insertion portion 12.

  The operation unit 14 includes an operation unit main body 22 having a gripping unit 22 a and a bend stopper 24 provided at the proximal end of the insertion unit 12. The operation portion main body 22 includes a first bending operation knob 26a that bends a bending portion 34 (to be described later) of the insertion portion 12 in the up and down direction, and a second bending operation knob 26b that bends in the left and right direction. Each of the first bending operation knob 26 a and the second bending operation knob 26 b is connected to the other end of an operation wire (not shown) whose one end is connected to the tip of the bending tube 42 of the bending portion 34. The first bending operation knob 26a and the second bending operation knob 26b include fixing levers 28a for fixing the first bending operation knob 26a and the second bending operation knob 26b in a rotated state. 28b is disposed.

  The insertion part 12 includes a distal end hard part 32, a bending part 34, and a serpentine part 36. Among these, the bending portion 34 is bent in a desired direction via the operation wire by a rotation operation by the first bending operation knob 26a and the second bending operation knob 26b of the operation unit 14.

  As shown in FIG. 2, the bending portion 34 includes a bending tube 42 formed by a plurality of joint pieces 44 pivotally connected to each other and an outer skin 46 covering the bending tube 42. The outer diameter of each joint piece 44 is about 10 mm, for example, and the thickness of the outer skin 46 is about 0.5 mm.

  The plurality of joint pieces 44 have the same shape except for the one disposed at the most distal end of the bending tube 42 and the one disposed at the most proximal end. For this reason, the bending tube 42 can be configured at a lower cost while suppressing the component cost and the manufacturing cost due to assembly.

  Here, of the joint pieces 44, the one disposed at the most distal end is called a first piece (not shown), and the one arranged at the most proximal end is the second piece (not shown). )). Further, among the joint pieces 44, those having the same shape and disposed between the first piece and the second piece are referred to as third pieces. Hereinafter, the third frame will be described with reference numeral 44 in the same manner as the joint frame 44.

  The third piece 44 of the bending tube 42 has a main body 52 formed in a short cylindrical shape (substantially ring shape) and each main body of the joint piece 44 adjacent from both ends of the main body 52 so as to be connected to the adjacent joint piece 44. Two pairs of arms 54 each extending in a pair toward 52 are provided. The two pairs of arms 54 extend along the axial direction of the bending portion 34. Of the two pairs of arms 54, one pair of arms is formed on one end side of the main body 52 of the third piece 44 at positions of 0 degrees and 180 degrees with respect to the center of the third piece 44. A pair of arms 54 are formed on the other end side of the main body 52 at positions of 90 degrees and 270 degrees with respect to the center of the third frame 44. The distal ends of the arms 54 of the adjacent third pieces 44 are pivoted. That is, the plurality of third pieces 44 are connected to each other so as to be rotatable.

  Further, although not shown, each of the first piece and the second piece includes a main body formed in a short cylindrical shape (substantially ring shape) and a pair of arms extending from one end of the main body. A pair of arms of the first frame and the second frame are formed at positions facing the central axis of the main body. The arm of the first piece is pivotally supported at the distal end of the arm 54 of the third piece 44 at the most distal end. The arm of the second piece is pivotally supported at the distal end of the arm 54 of the most proximal third piece 44. Therefore, the bending tube 42 is, for example, relative to the central axis of the bending tube 42 by sequentially pivoting one first piece, a plurality of third pieces 44, and one second piece. It can be rotated in four directions (vertical direction and horizontal direction).

  Guide portions (not shown) for guiding four (two pairs) operation wires (not shown) are formed inside the second piece and the third piece 44, respectively. An operation wire is inserted through each guide portion. The distal end of the operation wire is fixed to the most advanced joint piece (first piece). On the other hand, the base ends of the two pairs of operation wires are connected to the first bending operation knob 26a and the second bending operation knob 26b of the operation unit 14 in pairs.

  As shown in FIGS. 3A and 3B, the outer skin 46 is formed in a substantially cylindrical shape. The outer skin 46 is formed of a material having flexibility and elasticity, such as rubber or a resin material. As shown in FIG. 3 (A), on the inner peripheral surface of the outer skin 46, a protruding portion (rotation amount limiting portion) that protrudes toward the central axis of the outer skin 46 at substantially constant intervals (width W). 46a is formed. These protrusions 46 a are formed in a state having a step with respect to the inner peripheral surface of the outer skin 46. In order to increase the contact area with the end of the joint piece 44, the protrusion 46a is preferably formed in a substantially rectangular parallelepiped shape having a longitudinal direction in the circumferential direction of the outer skin 46. In addition, as shown in FIG. 2, these protruding portions 46 a are formed so as to be disposed at a position avoiding the arm 54 of the joint piece 44. The protrusion 46a may be formed integrally with the outer skin 46 by, for example, extrusion molding, or another member may be bonded to the inner peripheral surface of the outer skin 46 by adhesion or the like.

As shown in FIG. 4, the protrusions 46 a are formed at a height that enters between the joint pieces 44 when the joint pieces 44 rotate with respect to each other. Then, as shown in FIG. 3 (A), these protrusions 46a itself, longitudinally along the direction of the width of the outer skin 46 (length), the width L _d of the distal end side (distal end hard portion 32 side) It shifts so as to be smaller than the width L _p on the proximal end side (side of the serpentine tube portion 36) and gradually increase from the distal end side toward the proximal end side.

  In addition, a mark (not shown) is attached to the outside of one end portion of the bending tube 42 in order to make it easy to determine the orientation of the outer skin 46 during manufacturing (assembling). Is preferred. Such a mark is preferably provided at one end of the outer skin 46 in order to define a circumferential position with respect to the bending tube 42. For this reason, it becomes easy to determine the distal end side and the proximal end side of the outer skin 46 at the time of manufacture, and the outer skin 46 can be arranged in a predetermined state with respect to the bending tube 42. Further, even after the outer skin 46 is disposed outside the bending tube 42, the distal end side and the proximal end side can be easily distinguished from each other by the mark of the outer skin 46.

  Note that the distal end of the outer skin 46 is fixed to the outer peripheral surface of the distal end hard portion 32 of the insertion portion 12 by, for example, thread winding. On the other hand, the base end of the outer skin 46 is fixed to the outer peripheral surface of the distal end of the serpentine tube portion 36 of the insertion portion 12 by, for example, thread winding.

Next, the operation of the endoscope 10 according to this embodiment will be described.
The first bending operation knob 26a and the second bending operation knob 26b of the operation unit 14 are rotated from a state where the bending portion 34 of the insertion portion 12 is straight. Then, the operation wire is pulled along the axial direction by the turning operation of the first bending operation knob 26a and the second bending operation knob 26b. For this reason, the joint pieces 44 of the bending tube 42 are each subjected to a force by the operation wires inserted through the guide portions, and the adjacent joint pieces 44 are sequentially rotated. That is, the bending tube 42 is bent.

  At this time, as shown in FIG. 4, one end of the joint piece 44 and the other end of the adjacent joint piece 44 are in contact with the side surface of the protruding portion 46 a of the outer skin 46. That is, the protrusion 46 a of the outer skin 46 is nipped and bitten by one end of the joint piece 44 and the other end of the adjacent joint piece 44. At this time, as shown in FIG. 3 (A), the width in the direction along the longitudinal direction of the outer skin 46 in the protruding portion 46a of the outer skin 46 is larger than the width Ld on the distal end side. . Therefore, when the bending portion 34 is bent and the joint piece 44 is brought into contact with the protruding portion 46a of the outer skin 46, the distal end side width Ld is larger than the proximal end side width Lp on the distal end side of the bending portion 34. Therefore, the amount of rotation until the rotation of the joint pieces 44 is restricted is larger than the base end side of the bending portion 34. Accordingly, in the bending portion 34, the distal end side where the rotation amount between the adjacent joint pieces 44 is large bends larger than the proximal end side where the rotation amount between the adjacent joint pieces 44 is small. That is, as shown in FIG. 5, the curvature of the distal end side, which is the distal end hard portion 32 side, of the curved portion 34 is larger than the curvature of the proximal end side, which is the serpentine tube portion 36 side. Therefore, the distal end side of the bending portion 34 can be bent more rapidly than the proximal end side. Then, the movable range of the distal end of the distal end hard portion 32 of the endoscope 10 can be increased, and the observation visual field from the distal end of the distal end hard portion 32 can be ensured satisfactorily.

As described above, according to this embodiment, the following effects can be obtained.
The width of the protrusion 46a in the direction along the longitudinal direction of the outer skin 46 can be set as appropriate. For this reason, the rotation amount of the adjacent joint pieces 44 can be easily controlled by setting the width of the protruding portion 46a. For example, if the width is reduced, the amount of rotation between the adjacent joint pieces 44 can be increased, and if the width is increased, the amount of rotation between the adjacent joint pieces 44 can be reduced. For this reason, the bending amount according to the position of the bending tube 42 can be easily set only by the configuration of the protruding portion 46 a of the outer skin 46.

  Since the bending tube 42 can be formed using the joint piece (third piece) 44 having the same shape, the cost of parts of the joint piece 44 can be kept low. Further, since it is not necessary to consider the connecting order of the joint pieces (third pieces) 44 when the bending tube 42 is manufactured, the manufacturing cost due to assembly can be kept low. Then, by simply disposing the outer skin 46 having the protruding portion 46a on the inner side in a predetermined position and a predetermined direction with respect to the bending tube 42, the bending portion 34 having different curvatures on the distal end side and the proximal end side can be easily formed. can do.

  Therefore, it is possible to provide the bending portion 34 of the endoscope 10 that can prevent an increase in component cost and manufacturing cost and can bend the distal end side more rapidly than the proximal end side.

  In the bending portion 34 of this embodiment, a blade (mesh tube) that is normally disposed between the bending tube 42 and the outer skin 46 can be removed. Therefore, the manufacturing process can be shortened and the number of parts can be reduced.

  In this embodiment, it has been described that the width Lp on the proximal end side is gradually increased from the width Ld on the distal end side of the protruding portion 46a. However, the width of the protruding portion 46a is changed from the distal end side to the proximal end side. It is also preferable that the same width Ld is obtained up to a predetermined position toward the predetermined position, and the same width Lp is provided from the proximal end side toward the distal end side to the predetermined position. That is, as shown in FIG. 5, the bending portion 34 is, for example, a first portion 62 on the distal end side, a second portion 64 on the proximal end side of the first portion 62, and a proximal end side of the second portion 64. When divided into the third portion 66, the width of the plurality of protrusions 46a of the first portion 62 is made constant, the width of the plurality of protrusions 46a of the second portion 64 is made constant, and the third portion 66 is made constant. It is also preferable to make the widths of the plurality of protrusions 46a constant. In this case, the curvature of the first portion 62 can be maximized, and the curvature of the second portion 64 and the curvature of the third portion 66 can be gradually decreased. That is, the bending state of the bending portion 34 can be controlled by the width of the protruding portion 46a.

  Next, a second embodiment will be described with reference to FIGS. This embodiment is a modification of the first embodiment. The same members as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 6 and 7, a protrusion (rotation amount limiting portion) 46 b having a substantially corrugated longitudinal section is formed on the inner peripheral surface of the outer skin 46. That is, the protrusion 46b in this embodiment is different from the protrusion 46a as described in the first embodiment.

The pitches (lengths of portions corresponding to half wavelengths) P ₁ , P ₂ , and P ₃ of the protrusions 46 b whose longitudinal sections are substantially corrugated are small on the distal end side (the distal end hard portion 32 side) of the outer skin 46, and on the proximal end side It is formed so that (the serpentine tube side) is larger than the tip side. In the case of this embodiment, there are three portions where the pitches P ₁ , P ₂ and P _{3 of} the protrusions 46b are constant (see FIG. 6). That is, with the outer tube 46 covered on the curved tube 42, there are a first portion 62, a second portion 64, and a third portion 66, as shown in FIGS. On the other hand, the portion corresponding to the amplitude of the wave in the protrusion 46b is substantially constant. That is, in the outer skin 46, the distal end side (first portion 62) has many portions that are thinner than the proximal end side (third portion 66). Therefore, the base end side of the outer skin 46 has fewer thin portions than the front end side, and tries to maintain a straight state as much as possible. Therefore, the distal end side of the outer skin 46 is easily bent and the proximal end side is not easily bent.

  Then, as shown in FIG. 8, when the bending tube 42 is disposed inside the outer skin 46 and the bending portion 34 is bent, the distal end side (the portion indicated by reference numeral 62) where the pitch of the protruding portions 46 b is small is the base end. It is easily bent compared to the side (portion 66). That is, the distal end side of the bending portion 34 has a larger curvature than the proximal end side, and the distal end side of the bending portion 34 can be bent more rapidly than the proximal end side.

Incidentally, the pitch of the distal end side of the first portion 62 so as to become P ₁ as the average and less than the pitch of the proximal end side of the first portion 62, the pitch of the distal end side of the second portion 64 first smaller than the pitch of the proximal end side of the second portion 64 so as to become P ₂ as an average, a distal end pitch of the third portion 66 and smaller than the pitch of the third base end side of the portion 66 it is preferable to make the P ₃ as an average Te. In particular, the pitch on the proximal end side of the first portion 62 is smaller than the pitch on the distal end side of the second portion 64, and the pitch on the proximal end side of the second portion 64 is the distal end side of the third portion 66. It is preferable that the pitch is smaller than this pitch. In this case, the curvature of the first portion 62 can be maximized, and the curvature of the second portion 64 and the curvature of the third portion 66 can be gradually decreased.

  Further, when it is not necessary to make the curvature on the distal end side of the outer skin 46 larger than the curvature on the proximal end side, a desired curved shape can be obtained by appropriately setting the pitch of the substantially corrugated protrusions 46b of the outer skin 46. Can do. That is, the bending amount of the bending tube 42 can be controlled according to the position by changing the flexibility of the outer skin 46 between the distal end side and the proximal end side according to the pitch of the protruding portions 46b.

  In this embodiment, it is also preferable that a gap be provided between the bending tube 42 and the outer skin 46 so as to be slidable even if they are in close contact with each other. Further, it is also preferable that a blade (not shown) is disposed between the bending tube 42 and the outer skin 46.

  Although several embodiments have been specifically described so far with reference to the drawings, the present invention is not limited to the above-described embodiments, and all the embodiments performed without departing from the gist of the present invention are described. Including implementation.

1 is a schematic diagram showing an endoscope according to a first embodiment of the present invention. The schematic fragmentary sectional view which shows the curved part of the insertion part of the endoscope which concerns on 1st Embodiment. (A) is a schematic fragmentary sectional view which shows the outer skin of the curved part of the insertion part of the endoscope which concerns on 1st Embodiment, (B) is schematic which follows the 3B-3B line in (A). Sectional drawing. The schematic fragmentary sectional view which shows the state which curved the bending part of the insertion part of the endoscope which concerns on 1st Embodiment, and clamped the protrusion part of the outer skin with the joint piece. Schematic which shows the state which curved the front-end | tip part side of the insertion part of the endoscope which concerns on 1st Embodiment. The schematic sectional drawing which shows the outer skin of the curved part of the insertion part of the endoscope which concerns on the 2nd Embodiment of this invention. Schematic which shows the state which curved the front-end | tip part side of the insertion part of the endoscope which concerns on 2nd Embodiment. The schematic fragmentary sectional view which shows the state which curved the bending part of the insertion part of the endoscope which concerns on 2nd Embodiment.

Explanation of symbols

  34 ... curved portion, 42 ... curved tube, 44 ... joint piece, 46 ... outer skin, 46a ... protrusion, 52 ... main body of joint piece, 54 ... arm

Claims (8)

A bending tube having a plurality of joint pieces connected to each other so as to be rotatable;
In a bending portion of an endoscope comprising an outer skin covering an outer periphery of the bending tube,
A plurality of protrusions that control the bending shape of the bending portion are formed on the outer skin along the longitudinal direction of the bending portion so as to protrude from the inner peripheral surface when the bending tube is covered. A bending portion of an endoscope characterized by being made.   The protrusion has a width in a direction along a longitudinal direction of the bending portion of the protruding portion, and the distal end side of the bending portion is formed smaller than the proximal end side of the bending portion. The bending portion of the endoscope according to claim 1. The joint pieces have at least some joint pieces each having the same shape,
The protrusions are disposed between the joint pieces of the same shape, and when the joint pieces of the same shape are rotated with respect to each other, on the end surface of one joint piece and the end side of the one joint piece. The bending portion of the endoscope according to claim 1, wherein the bending portion has a height sandwiched between end faces of the other adjacent joint pieces.   The bending portion of the endoscope according to claim 1, wherein the protruding portion has a longitudinal section of the outer skin formed in a substantially wave shape. An endoscope comprising an elongated insertion portion having a bending portion that is bent by an operation by an operation portion on a distal end side,
The curved portion is
A curved tube in which a plurality of joint pieces are connected to be rotatable along the axial direction of the insertion portion;
A tubular outer shell covering the outer periphery of the bending tube;
The endoscope, wherein the outer skin is provided with a plurality of protrusions for controlling the amount of rotation of the joint piece on an inner peripheral surface along a longitudinal direction of the bending portion.   6. The protruding portion is formed such that a width in a direction along a longitudinal direction of the bending portion is formed smaller on a distal end side of the bending portion than on a proximal end side of the bending portion. The endoscope according to 1. The joint pieces have at least some joint pieces each having the same shape,
The internal projection according to claim 5 or 6, wherein at least a part of the protrusion is formed in a state having a step difference in a convex state with respect to the inner peripheral surface of the outer skin. mirror.   The endoscope according to claim 5 or 6, wherein the protruding portion is formed smoothly and continuously with respect to the inner peripheral surface of the outer skin.

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