JP2610318B2 - Endoscope - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an endoscope provided with a curved portion in an insertion portion.

[Prior art] In recent years, by inserting an elongated insertion portion into a body cavity,
2. Description of the Related Art Endoscopes capable of observing organs in a body cavity and the like and performing various treatments using a treatment tool inserted into a treatment tool channel as necessary are widely used.

Among the endoscopes, in a flexible endoscope in which the insertion portion is soft,
A bending portion that can be bent by operation on the hand side is provided at the distal end side of the insertion portion. In a conventional endoscope, when a bending operation is performed, there is a tendency that the bending portion starts to be bent from the proximal side of the bending portion and the distal end side is not easily bent. In the case of such a bending operation, there is a problem that a radius of curvature becomes large, and it is not possible to perform a sufficient bending in a small space, or to keep a sufficient distance from an inner wall of a body cavity.

To cope with this, for example, Japanese Utility Model Publication No. 53-20953 and Japanese Patent Application Laid-Open No. 62-242134 disclose, in order to improve the curved shape, the thickness of a skin covering the outer circumference of a curved tube constituting a curved portion. A variation is disclosed.

[Problems to be Solved by the Invention] However, in a conventional endoscope having an outer skin with an uneven thickness, the thickness of the outer skin is changed at a portion where the outer diameter of the bending tube is uniform, so The outer diameter of the part was uneven. As described above, if the outer diameter of the curved portion is not uniform, it causes pain to the patient, the slipperiness of the curved portion deteriorates, the insertion property is deteriorated, and the outer skin often suffers external damage. There is a point.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an endoscope that can improve a bending operation of a bending portion and has a uniform outer diameter of the bending portion.

[Means for Solving the Problems] The endoscope according to the present invention includes a curved tube portion in which a plurality of cylindrical members are rotatably connected to an insertion portion, and a covering member that covers the curved tube portion. Wherein the bending portion having at least one cylindrical member having an outer diameter different from that of another cylindrical member is provided in the bending tube portion, and the cylindrical member having the larger outer diameter is provided at the distal end. The coating member was arranged in order from the side, and the thickness was changed with respect to the outer diameter of the cylindrical member so that the outer diameter of the bending portion was substantially uniform when the bending tube portion was coated. Things.

[Operation] In the present invention, the bending operation of the bending portion can be improved by changing the thickness of the covering member, and the outer diameter of the bending portion formed by the bending tube portion and the covering member becomes substantially uniform.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 4 relate to an embodiment of the present invention.
FIG. 2 is a sectional view of the bending portion, FIG. 2 is a side view of the endoscope, FIG. 3 is an explanatory diagram showing a bending shape of the bending portion of the endoscope of the present embodiment,
FIG. 4 is an explanatory view showing a curved shape of a curved portion of a conventional endoscope.

As shown in FIG. 2, the endoscope 1 includes an elongated and flexible insertion section 2, a large-diameter operation section 3 connected to the rear end of the insertion section 2, and the operation section 3. An eyepiece 4 connected to the rear end of the camera and a light guide cable 5 extending from the side of the operation unit 3 are provided. At the end of the light guide cable 5, a connector 6 that is detachably connected to a light source device (not shown) is provided.

The insertion section 2 is composed of a hard distal component 9, a bendable bending section 10, and a soft flexible tube 11, which are sequentially provided from the distal side. The operation section 3 is provided with a bending operation knob 12 for performing a bending operation on the bending section 10.

The distal end portion 9 is provided with a through hole for illumination and a through hole 15 for observation (not shown). In the lighting through hole,
An illumination lens is mounted on the distal end side, and a light guide made of a fiber bundle (not shown) is continuously provided at the rear end of the illumination lens. The light guide is inserted through the insertion section 2, the operation section 3, and the light guide cable 5 and is connected to the connector 6. Then, the light emitted from the light source device passes through the light guide and the illumination lens to irradiate the subject.

An objective lens system 18 is mounted in the observation through-hole 15 via a lens frame 17. At the image forming position of the objective lens system 18, a distal end surface of an image guide 19 made of a fiber bundle is arranged. This Image Guide 19
Is inserted through the insertion portion 2, and a rear end face faces an eyepiece (not shown) in the rear eye portion 4. The subject image formed by the objective lens system 18 is transmitted to the eyepiece 4 by the image guide 19 and is observed from the eyepiece 4.

The bending portion 10 is configured as shown in FIG.

That is, the bending portion 10 includes a bending tube 20 formed by rotatably connecting a plurality of cylindrical joint pieces 21 to each other,
Has a metal mesh tube 22 and an outer skin 23 which sequentially cover the outer periphery of the metal mesh tube. The foremost first joint piece 21a of the joint pieces 21 is externally fitted and connected to the rear end of the distal end component 9. Behind the first joint piece 21a, several joint pieces 21 having the same outer diameter as that of the first joint piece 21a are rotatably connected. A bulge joint piece 21b having a changed diameter is connected. Behind the bulge joint piece 21b, several joint pieces 21 having the same outer diameter as the rear end side of the bulge joint piece 21b, that is, smaller than the first joint piece 21a, are rotatably connected. Finally, a final joint piece 21c having the same outer diameter as the rear end side of the bulge joint piece 21b.
Are connected. The final joint piece 21c is
Connected to the tip of 1.

In this manner, in the present embodiment, the outer diameter of the bending tube 20 at the rear end side is smaller than the outer diameter at the front end side at a position where the outer diameter of the bulge joint piece 21b changes. .

Further, the outer skin 23 is made of, for example, rubber or synthetic resin, and a thickness at a rear end side is larger than a thickness at a front end side at a position where an outer diameter of the bulge joint piece 21b changes. . The difference in thickness between the distal end side and the rear end side of the outer skin is set substantially equal to the difference in the outer peripheral radius between the rear end side and the distal end side of the curved tube 20. Accordingly, when the outer periphery of the curved tube 20 is covered with the outer skin 23 via the metal mesh tube 22, as shown in FIG. 1, the outer diameter of the curved portion 10 is substantially uniform.

The front end of the outer skin 23 is externally fitted to the rear end of the front end component 9, fixed by winding a thread 25, and an adhesive 26 is laminated on the thread 25. Similarly, the rear end of the outer skin 23 is externally fitted to the front end of the flexible tube 11, is fixed by winding a thread 25, and an adhesive 26 is laminated on the thread 25. Note that the front end component 9 is covered with an insulating cover 27.
And the outer diameter of the curved portion 10 are substantially equal. Further, the outer diameter of the bending portion 10 and the outer diameter of the flexible tube 11 are substantially equal.

Further, for example, the tip portions of four angle wires 32 are fixed to the inner peripheral portion of the first joint piece 21a by, for example, four angle wire fixing portions 31. This angle wire
32 is inserted through the inside of the bending tube 20 and the flexible tube 11, and the rear end portion is
It is connected to a wire drive mechanism driven by the bending operation knob 12 of the operation unit 3. An angle wire 32 in the bending tube 20 is slidably supported by an angle wire guard 33 provided on an inner peripheral portion of each joint piece 21.

Further, as shown in FIG. 1, the distal end component 9 and a built-in insertion portion such as the image guide 19 and a light guide (not shown) are connected in the first joint piece 21a. The outer diameter 35 of the connecting portion between the distal end component 9 and the built-in component is larger than the outer diameter 36 of the built-in component located behind the connecting portion. Therefore, the joint piece 21 having a smaller outer diameter (smaller inner diameter) than the first joint piece 21a can be connected behind the bulge joint piece 21b.

As described above, according to the present embodiment, the thickness of the rear end side of the outer skin 23 is thicker than the thickness of the front end side with respect to the bulge joint piece 21b, so that the front of the bulge joint piece 21b is When the bending resistance is lower than the rear and the bending portion 10 is bent,
The front of the bulge joint piece 21b can start to bend earlier. Also, as described above, the bulge joint piece 21b
Since the front portion starts to bend earlier, the bending portion 10 can be bent with a small radius of curvature, and when observing the stomach angle or the like, a sufficient distance from the stomach angle can be maintained.

With reference to FIGS. 3 and 4, a comparison will be made between the curved shape of the curved portion 10 of the endoscope 1 of the present embodiment and the curved shape of the curved portion 10 of the conventional endoscope. As shown in FIG. 3, when the bending portion 10 of the endoscope 1 of the present embodiment is bent at an angle theta _1, the center axis of the flexible tube, the distal end construction part 9 furthest from the central axis As shown in FIG. 4, the distance between the end of the flexible tube and the center axis of the flexible tube is assumed to be h ₁ when the bending portion 10 of the conventional endoscope is bent at an angle θ _2. the distance between the farthest ends of the distal end construction part 9 and h _2. In the endoscope 1 of the present embodiment, the bending portion 10 can be bent with a small radius of curvature by starting to bend ahead of the bulge joint piece 21b, so that when θ ₁ = θ ₂ , , H ₁ <h ₂ , and the bending portion 10 can be bent in a smaller space, that is, the viewing direction can be changed.

Further, in the present embodiment, with the bulge joint piece 21b as a boundary,
The outer diameter of the rear end side of the bending tube 20 is made smaller than the outer diameter of the front end side, and the thickness of the rear end side of the outer skin 23 is made thicker than the front end side. The outer diameter is substantially uniform. Therefore, the patient's pain is reduced.

Further, since the outer diameter of the curved portion 10 is uniform, the slipperiness of the curved portion 10 is improved, and the insertability into the large intestine and the like is also improved. Further, external damage to the outer cover 23 is reduced.

5 to 8 relate to an example of a distal end portion of the endoscope to which the present invention is applied. FIG. 5 is a sectional view of the distal end portion, and FIG. 6 is a sectional view taken along line AA 'of FIG. FIG. 7 is a sectional view taken along the line CC 'of FIG.
FIG. 8 is a sectional view taken along line B of FIG.

FIG. 5 shows an example of a side-view type electronic endoscope. The distal end component 9 has a main body 41, and an illumination window 42 and an observation window 43 are provided on one side of the main body 41 in this order from the distal end side. In addition, a forceps port 44 is formed. Further, the illumination window 42, the observation window 43, the forceps port 44
The outer peripheral portion and the distal end portion of the main body 41 excluding the side portion provided with are covered with a cover member 45.

Inside the main body 41, a vertical portion 47a communicating with the illumination window 42 and extending vertically downward from the illumination window 42,
Horizontal section that communicates with 7a, opens at the side, and extends rearward in the axial direction
An illumination groove 47 made of 47b is formed. The opening on the side of the horizontal portion 47b is closed by the cover member 45. The illumination window is provided with an illumination lens. At the rear end of the illumination lens 48, a light guide 50 is continuously provided. Light guide 50 in this example
Has a light guide fiber molding portion 51 without a protective sheath on the distal end side.
Reference numeral 51 is inserted through the groove 47, and the illumination light emitting end face 52 at the front end faces the rear end face of the illumination lens 48. Further, the light guide fiber forming part 51 is provided with the groove 47.
Of the horizontal portion 47b, and the vertical side wall 54 (see FIG. 5) and the horizontal side wall 55 (see FIG. 6) of the vertical portion 47a.

In this manner, the light guide fiber molded portion 51 without the protective sheath is attached to the bottom surface 53 of the groove portion 47 provided in the main body 41 and the vertical and vertical portions.
By striking the side walls 54, 55, the illumination lens 48
And the position of the illumination light emitting end face 52 of the light guide 50 are made accurate, and uniform illumination light can be secured in the field of view. That is, conventionally, the light guide fiber molding portion 51 is covered with a protective sheath such as a urethane tube, and the moldability of the molding portion 51 is poor, and the positioning accuracy of the emission end surface 52 is not obtained. The illumination light that is delicately moved in the axial direction of the part 2 and emitted is adjusted so as to have uniform brightness in the visual field. On the other hand, according to the present example, the light distribution adjustment work as in the related art becomes unnecessary. Further, by eliminating the protective outer cover, the moldability of the light guide is improved. Further, the distal end portion 9 can be reduced in diameter by the space of the protective outer cover.

As shown in FIG. 6, an elastic member 57 such as rubber is attached to the light guide fiber molding portion 51 at a position opposite to the lateral side wall 53 of the groove portion 47. The operation of fixing the light guide fiber forming section 51 to the groove 47 is performed as follows. That is, the light guide fiber forming part 51 is inserted into the groove part 47, and the groove part 47 is filled with, for example, a silicon-based adhesive 59 and fixed, but until the adhesive 59 is dried, the light guide fiber is The molded portion 51 is connected to the side wall 55 of the groove 47.
And temporarily fix it. At this time, since the elastic member 57 is interposed between the screw 58 and the light guide fiber forming portion 51, the light guide fiber forming portion 51 is prevented from being damaged by the screw 58.

On the other hand, the observation window 43 has a first optical system constituting an objective optical system.
A lens 61 is attached by an adhesive 60, and the first lens
At the rear end of 61, a prism 63 held by a frame 62 is continuously provided. The rear end surface of the first lens 61 has a flare stop.
64 are provided. The prism 63 reflects the light beam passing through the first lens 61 so as to guide the light beam axially rearward of the insertion section 2. On the extension of the optical axis of the light beam reflected by the prism 63, a lens system 65 constituting an objective optical system is provided. The lens system 65 is held by a metal lens frame 67, for example.
Is covered by a reinforcing metal frame 69 via an insulating frame 68. The reinforcing metal frame 69 is fixed to a hole formed in the main body 41.

By the way, in this example, the reinforcing metal frame 69 and the lens frame 67
During this time, the adhesive 70 is injected. That is, when a resin is used for the insulating frame 68, adhesion between the insulating frame 68 and the reinforcing metal frame 69 is poor because the adhesiveness with the reinforcing metal frame 69 is low. Reinforced metal frame 69
And indirectly adhered. This allows the insulation frame
The adhesive strength between 68 and the reinforcing metal frame 69 is improved.

At the rear end of the lens frame 67, the front end of an image pickup device fixing frame 72 is fitted and joined. A plate-shaped optical member 73 is mounted on the front end of the imaging device fixing frame 72, and a flare stop 74 is provided on both surfaces of the optical member 73. Further, an imaging device 75 using a CCD or the like is disposed behind the optical member 73 in the imaging device fixing frame 72 and at an image forming position of the objective optical system.

By the way, in this example, as shown in FIG. 7, the shape of the opening 77 of the flare stop 74 is similar to or similar to the shape of the use image area 78 of the imaging device 75. It is designed so as not to block the rays incident on 78. Thus, the field of view is not blurred, and flare can be effectively prevented.

In FIG. 5, reference numeral 81 denotes a light receiving portion of the image pickup device 75, and in FIG. 8, reference numeral 82 denotes a ridge line of the spherical portion of the first lens 61, and reference numeral 83 denotes a flare stop surface. The image area 78 is virtual.

A signal cable 85 is connected to the imaging device 75. Further, an outer peripheral portion of the imaging device fixing frame 72 is covered with a heat shrinkable tube 86.

As shown in FIG. 6, the main body 41 has a forceps port.
A forceps base groove in which a forceps table (not shown) is stored in communication with 44
91 are provided.

As shown in FIG. 5, the main body 41 is provided with an air / water supply nozzle 92 which opens toward the observation window 43 in the axial direction rearward of the insertion portion 2 of the observation window 43 by an adhesive 92. Installed. The main body 41 includes the air / water supply nozzle.
A hole 94 communicating with 92 is provided, and an air / water supply tube 96 is connected to the rear end of the hole 94 via a base 95.

9 and 10 relate to another example of the distal end portion of the endoscope to which the present invention is applied, FIG. 9 is a cross-sectional view of the distal end portion viewed from the rear end side, and FIG. It is sectional drawing of a vicinity.

 This example is an example of a direct-view type electronic endoscope.

As shown in FIG. 9, four angle wire fixing portions 31 for fixing four angle wires 32 are provided on the inner peripheral portion of the first joint piece 21a of the bending tube 20. In the first joint piece 21a, a light guide fiber bundle 101 covered with a light guide protection tube 102 made of an insulating material, a channel tube 103 forming a forceps channel 113, as built-in parts of the insertion portion, Air supply / water supply tube 104 covered by air / water supply protection tube 105
And the imaging device 107 are housed. These built-in components are arranged between the angle wire fixing portions 31.

Incidentally, as shown in FIG. 10, the imaging device 107 is covered by a shield member 108, and the shield member 108 is further covered by a heat-shrinkable tube 109 made of an insulating material. The shield member 108 is formed of a member having good conductivity (usually a metal). In this example, the heat-shrinkable tube 109 is partially notched. Since the notch portion 110 exposes the shield member 108 having good conductivity such as a metal, as shown in FIG. 9, the built-in component adjacent to the shield member exposed portion 111 formed by the notch portion 110 is made of an insulating material. For example, a light guide protection tube 102 is used.

As described above, by partially notching the heat-shrinkable tube 109, the diameter of the insertion portion can be reduced.

In this example, the internal components of the insertion section are arranged as shown in FIG. That is, when viewed from the rear end side, an imaging unit 112 including the imaging device 107 is arranged at the upper right, a forceps channel 113 is arranged at the lower left, and the light guide fiber bundle 101 is arranged at the upper left. On the other hand, conventionally, for example, as shown in FIG. 11, the arrangement of the imaging unit 112 and the forceps channel 113 is the same as that of the present example, but the light guide fiber bundle 101 is arranged at the lower right. The monitor image in the case of such a conventional arrangement is shown in FIG.
Shown in the figure. As shown in this figure, the target
When the forceps 116 inserted through the forceps channel 113 is directed to the 115, a shadow 117 of the forceps 116 appears on the upper left, and the shadow 11
7 can hide target 115.

In contrast, the monitor image in the case of the arrangement of this example is
As shown in FIG. 14, the shadow 117 of the forceps 116 appears on the lower side, and the forceps 116
When aiming 116 at target 115, this shadow 117 causes target 1
15 can be seen well without hiding. Therefore,
It becomes easier to perform procedures such as biopsy.

In this example, as shown in FIG. 9, the thickness t ₁ of the air / water supply tube 104 made of, for example, a Teflon tube,
Is thinner than the thickness t ₂ of the tube 104 to cover for example the protective tube 105 made of a polynomial interstitial Teflon tube.

Further, as shown in FIG. 9, when the signal cables 119 connected to the imaging device 107 are divided into two groups,
The two groups of signal cables 119, 119 are diagonally arranged on the rear end face of the image forming device 107 so that the angle wire fixing portion 31 in the first joint piece 21a does not interfere with the signal cable 119,
It is arranged along the radial direction of the insertion part.

FIG. 15 is a sectional view showing another example of the insertion portion of the endoscope to which the present invention is applied, and FIG. 16 is a modification of the insertion portion shown in FIG.

In the example shown in FIG. 15, the bending portion 10 is, as in FIG.
Around the bulge joint piece 21b, the outer diameter of the rear end side of the bending tube 20 is made smaller than the outer diameter of the front end side, and the thickness of the rear end side of the outer skin 23 is made larger than the thickness of the front end side. By increasing the thickness, the outer diameter of the curved portion 10 is made substantially uniform.

In the example shown in FIG. 16, the outer diameter of the first joint piece 21a is changed on the way so that the rear has a smaller diameter.
The joint pieces 21 behind the first joint piece 21a are all the first joint pieces 21a.
The outer diameter of the joint piece 21a is the same as the outer diameter of the rear end side. Further, the outer diameter of the curved portion 10 is increased by making the thickness of the rear end of the outer skin 23 thicker than the thickness of the front end side at a position where the outer diameter of the first joint piece 21a changes. It is almost uniform. Further, the inner diameter D _{1 of the} curved tube 20 is larger than the inner diameter D ₂ of the flexible tube 11.
Is larger. This reduces the load on the internal components in the bending tube 21 during bending.

Other configurations are the same as those in FIGS. 15 and 16. That is, the illumination through-hole 12 provided in the distal end component 9 is provided.
An illumination lens 123 is attached to 1 via a lens frame 122. The front end of the light guide fiber bundle 126 is connected to the rear end of the illumination through-hole 121 via a base 125. Further, an air / water supply nozzle 142 is attached to the front end side of the air / water supply through-hole 141 provided in the front end configuration unit 9, and an air / water supply tube 144 is provided at the rear end side via a base 143. It is connected. An air / water supply tube branch 145 is provided at the rear end of the air / water supply tube 144, for example, at a position slightly behind the boundary between the curved portion 10 and the flexible tube 11.

By the way, the light guide fiber bundle 126
Is covered with a protective tube 131 made of, for example, a porous Teflon tube inside the curved portion 10, and
The inside is covered with a protective tube 132 made of, for example, silicone rubber. Then, from the outer diameter d ₃ of the protective tube 131, the outer diameter d ₄ of the protective tube 132 is small. Further, a joint 133 between the protection tubes 131 and 132 is a joint between other built-in components, for example, an air / water supply tube branch portion 145.
, The length is set so as not to interfere in the axial direction.

The protection tube 131 and the protection tube 132 are
Connected within. Considering the durability of the light guide fiber bundle 126 in the bending portion 10, the filling rate of the fiber in the protection tube 131 is set to a low value of about 60%,
Assuming that the filling rate of the fiber in 2 is about 85%, if the light guide fiber is 3000 pieces and the fiber diameter is 30μm, the protective tube
131 inner diameter d ₁ = φ2.4 mm, protective tube 132 inner diameter d ₂ = φ ₂
mm, the thickness t ₁ of the protective tube 131 is 0.2 mm, and the thickness t ₂ of the protective tube 132 is 0.1 mm (pole, general thickness), and the outer diameter d ₃ of the protective tube 131 is 2.8 mm. , Protection tube
The outer diameter of 132 is d ₄ = φ2.2 mm. Therefore, d ₃ > d ₄ .

Note that the present invention is not limited to the above-described embodiment. For example, the bending operation is not limited to the embodiment in which the outer diameter of the joint piece 21 on the hand side of the bending portion 10 is reduced and the outer skin 23 is thickened as in the embodiment. In, the outer diameter of the joint piece 21 at a portion to be bent later in time may be reduced, and the outer skin 23 may be thickened to make the outer diameter of the total curved portion 10 uniform. For example, the outer diameter of the joint piece 21 may be made smaller and the outer diameter 23 may be made thicker near the front end or in the middle of the curved portion 10 as described above.

Further, the outer diameter of the joint piece 21 and the thickness of the outer cover 23 may be changed at a plurality of locations or may be changed continuously.

[Effects of the Invention] As described above, according to the present invention, the curved portion is located closer to the distal end as the outer diameter of the cylindrical member is larger, and the cylindrical portion is formed such that the outer diameter of the curved portion becomes substantially uniform. The thickness of the covering member changes according to the outer diameter of the member. For this reason, a portion having a small thickness of the covering member has a low bending resistance, and a portion having a large thickness has a high bending resistance, so that the difference in the thickness of the covering member is effectively changed to the difference in the bending resistance. Therefore, when the bending resistance is lower toward the distal end and the bending portion is bent, the bending starts from the distal end first, so that the bending operation of the bending portion can be improved, and the outer diameter of the bending portion becomes substantially uniform. There is.

[Brief description of the drawings]

1 to 4 relate to an embodiment of the present invention. FIG. 1 is a sectional view of a bending portion, FIG. 2 is a side view of an endoscope, and FIG. 3 is a side view of the endoscope of the present embodiment. FIG. 4 is an explanatory diagram showing a curved shape of a bending portion, FIG. 4 is an explanatory diagram showing a curved shape of a bending portion of a conventional endoscope,
5 to 8 relate to an example of a distal end portion of the endoscope to which the present invention is applied. FIG. 5 is a sectional view of the distal end portion, and FIG. 6 is a sectional view taken along line AA 'of FIG. 7, FIG. 7 is a sectional view taken along the line CC 'of FIG. 5, FIG. 8 is a view taken in the direction of arrow B in FIG. 5, and FIGS. 9 and 10 are end portions of the endoscope to which the invention is applied. 9 is a cross-sectional view of the distal end portion viewed from the rear end side, FIG. 10 is a cross-sectional view of the vicinity of the imaging device, and FIG. 11 is an example of an arrangement of a built-in component of the conventional insertion unit. , FIG. 12 is an explanatory view showing a monitor image in the case of the arrangement of FIG. 11, FIG. 13 is an explanatory view showing the arrangement of the internal part of the insertion portion in the example of FIG. 9, and FIG. No.
FIG. 13 is an explanatory view showing a monitor image in the case of the arrangement of FIG. 13, FIG. 15 is a cross-sectional view showing another example of the insertion section of the endoscope to which the present invention is applied, and FIG. 16 is an insertion section shown in FIG. This is a modified example. DESCRIPTION OF SYMBOLS 1 ... Endoscope, 2 ... Insertion part 9 ... Tip part, 10 ... Bending part 11 ... Flexible tube, 20 ... Bending tube 21, 21a, 21b, 21c ... Joint piece 23 ... Outer skin

Claims (1)

(57) [Claims] 1. An endoscope provided with a bending portion having a bending tube portion formed by connecting a plurality of cylindrical members so as to be rotatable with each other and a coating member covering the bending tube portion. In the curved tube portion, while having at least one cylindrical member having a different outer diameter with respect to another cylindrical member, the cylindrical member having the larger outer diameter is arranged in order from the front end side, and the coating member is An endoscope, wherein a thickness of the cylindrical member is changed with respect to an outer diameter of the cylindrical member so that an outer diameter of the curved portion becomes substantially uniform when the curved tube portion is covered.