WO2008047797A1

WO2008047797A1 - Structure for endoscope curve section

Info

Publication number: WO2008047797A1
Application number: PCT/JP2007/070187
Authority: WO
Inventors: Hideya Kitagawa; Hirokazu Tanaka; Takashi Nakayama
Original assignee: Olympus Corporation
Priority date: 2006-10-18
Filing date: 2007-10-16
Publication date: 2008-04-24
Also published as: JP2008099827A

Abstract

A structure for an endoscope curve section, in which an outer skin tube (38) is placed along the direction of insertion of an insertion section (2) of an endoscope (1) and in which a protrusion (39) is provided at that portion of the outer skin tube (38) that is located at a gap (S) between node rings (31). The protrusion (39) of the outer skin tube (38) is adapted such that, when each node ring (31) is rotated, the protrusion (39) is deformed so as to bend outward at a portion located on the inner side of the bend of a curve section (5). This prevents the outer skin tube (38) from being pinched between node rings (31) when the curve section (5) is bent. Thus, the structure prevents the outer skin tube (38) from being pinched between node rings (31) when the curve section (5) is bent and facilitates production of the insertion section (2) of the endoscope (1).

Description

Specification

Endoscope bending structure

Technical field

TECHNICAL FIELD [0001] The present invention relates to a bending portion structure of an endoscope in which a bending portion that can be bent is disposed on a distal end side of a insertion portion that is inserted into a body.

Background art

[0002] Generally, in a flexible endoscope, an operation portion on the proximal side is disposed on the proximal end side of the insertion portion inserted into the body. The insertion portion has an elongated flexible tube portion, a bendable bending portion, and a leading end hard portion. The bending portion is connected to the tip of the flexible tube portion. The distal end hard portion is disposed at the most distal portion of the insertion portion. A proximal end portion of the flexible tube portion is connected to the operation portion.

[0003] The bending portion has a plurality of node rings. The plurality of node rings are juxtaposed along the insertion direction of the insertion portion. Between the front and rear nodes, the front and rear nodes are connected to each other by pivots such as rivets. Further, on the distal end side of the bending portion, for example, the distal end portions of four bending operation wires for bending the bending portion in four directions of up, down, left and right are fixed. The proximal end portions of these bending operation wires are extended to the operation portion on the proximal side through the inside of the flexible tube portion.

[0004] The operation section on the hand side is provided with a bending operation mechanism section for bending the bending section in, for example, four directions, up, down, left, and right. The bending operation mechanism section is connected to the base ends of the four bending operation wires. Further, the bending operation mechanism section includes an up / down bending operation knob and a left / right bending operation knob. Then, one of the four bending operation wires is pulled by the rotation operation of the up / down bending operation knob or the left / right bending operation knob. The bending portion can be operated in the four directions of up / down / left / right via the bending operation wire pulled here, or! / ヽ can be operated in an arbitrary direction by an arbitrary angle by a plurality of bending operation wires. It is supposed to be done.

[0005] Also, Japanese Patent Publication No. 8-17766 (Patent Document 1) shows an example of a conventional bending structure of an endoscope. Here, on the outer peripheral surface of the front end of each node ring, a pair protruding forward The front projections of each are projected at 180 °. Further, on the outer peripheral surface of the rear end portion of each node ring, a pair of rear projecting portions projecting rearward is provided at a position of 180 °. The front projecting portion and the rear projecting portion are each disposed at a position of 90 ° in the circumferential direction. Then, the rear protruding portion of the front node ring and the front protruding portion of the rear node ring are overlapped (hereinafter referred to as polymerization) to form a superposed portion. A through hole is formed in the overlapped portion, and a rivet is inserted into the through hole. In this state, a rivet is caulked to form a rotation support shaft (support shaft portion) that rotatably connects the node rings. As a result, a link structure is formed in which the bending portion is bent in four directions, for example, up, down, left, and right, by the plurality of node rings.

[0006] Furthermore, the outer peripheral surface of the bending tube in which a plurality of node rings are arranged side by side is covered with an outer skin such as a rubber tube. Here, in the bending tube of the endoscope of Patent Document 1, a protection net is interposed between the node ring and the outer skin. When rotating the up / down bending operation knob or the left / right bending operation knob, the bending operation of the four bending operation wires! Is done. Further, the bending portion is bent in an arbitrary direction by any one of the four bending operation wires. At the time of this bending operation, the interval between the node rings is widened at the portion located outside the bend as the node rings rotate. Thereby, a tensile force acts on the outer skin and the outer skin extends. At the same time, in the part located inside the bend, the spacing between the nodes is narrow. As a result, a compressive force acts on the outer skin to compress the outer skin. At this time, the protective net protects the outer skin from being bitten between the joint rings of the bending tube at the portion where the distance between the joint rings is narrow.

Disclosure of the invention

[0007] In the bending portion structure of the endoscope having the above-described conventional configuration, the protective net needs to maintain a slippery state in a non-fixed state with respect to both the outer peripheral surface of the node ring and the inner peripheral surface of the outer skin. . For this reason, those woven with metal strands such as stainless steel are widely used because of their functional aspects. However, the production of the protective net requires high-precision bladers and metal processing technology such as terminal processing, which raises the problem of increased manufacturing costs.

[0008] The present invention has been made paying attention to the above circumstances, and its purpose is not to use a protective net. However, an object of the present invention is to provide a bending portion structure of an endoscope that can prevent the outer skin from being bitten between the node rings when the bending portion is bent and can easily manufacture the endoscope insertion portion.

[0009] In the first aspect of the present invention, a plurality of node rings are arranged in parallel along the insertion direction of the endoscope insertion portion, and the front and rear node rings rotate around a support shaft portion, respectively. A bending tube that is connected to the bending tube, and includes a bending portion that is formed in a cylindrical shape with an elastic material and is directly fitted on an outer periphery of the bending tube; A bending portion structure of an endoscope that causes the bending portion to bend in accordance with a moving operation, wherein the outer skin is positioned in a gap portion between the node rings along the insertion direction of the endoscope insertion portion. The biting prevention portion bends the outer skin outward at a portion located on the inner side of the bending portion of the bending portion during the rotation of each node ring of the bending portion. A bending portion structure of an endoscope which prevents the outer skin from being bitten between the node rings by deforming in a direction.

[0010] And, in the above configuration, the space between the node rings is widened at the portion located on the outside of the bend during the rotation operation of each node ring of the bending portion, so that a tensile force acts on the outer skin to extend the outer skin. The space between the node rings is narrowed at the portion located on the inner side of the bend, so that the outer skin is compressed by the compressive force acting on the outer skin. At this time, when a force in the compression direction acts on the outer skin at a portion where the distance between each ring is narrow, the outer skin is deformed in the direction of bending outward by the biting prevention portion of the outer skin. It prevents the outer skin from invading between the rings and being bitten. As a result, the protective net used in the conventional curved portion is omitted, and the manufacture of the endoscope insertion portion is facilitated.

[0011] Preferably, the biting prevention unit has at least an inner peripheral surface of the outer skin portion positioned at a gap portion between the node rings along the insertion direction of the endoscope insertion part. A bulging portion that bulges to a diameter larger than the diameter of the fitting surface of the outer skin that is fitted to the outer skin.

[0012] In the configuration described above, a tensile force acts on the outer skin by increasing the distance between the node rings at a portion located on the outer side of the bending portion of the bending portion with the rotation of each node ring of the bending portion. Then, the outer skin is stretched, and the space between the node rings is narrowed at the portion located on the bending inner side of the bending portion, so that the outer skin is compressed by the force in the compression direction acting on the outer skin. At this time, between each node ring When a force in the compression direction is applied to the outer skin at a portion where the gap between the outer rings is narrowed, the outer skin is deformed in a direction to bend outward by the bulging portion of the outer skin located in the gap between the node rings. Prevents the outer skin from invading and biting between each node ring. Furthermore, since the bulging portion of the outer skin can easily extend and deform the portion located outside the bending portion of the bending portion, the portion located outside the bending portion of the bending portion should not be stretched to obstruct the bending. It is a thing.

[0013] Preferably, the bulging portion is thinner than a thickness of a wall portion of the outer skin formed by a fitting portion of the outer skin fitted to the node ring. .

[0014] And, in the above configuration, the bulging portion is made thinner than the thickness of the wall portion of the non-bulging portion formed by the fitting portion of the outer skin! Easily deform the bulge. As a result, the space between the node rings is narrowed at the portion located inside the bending portion of the bending portion in accordance with the turning operation of each node ring of the bending portion, so that a force in the compression direction acts on the outer skin and the outer skin is When compressed, the outer skin is easily deformed in the direction of bending outward to prevent the outer skin from invading between each ring and being bitten. Furthermore, the bulging part of the outer skin is bent when the outer skin stretches due to the pulling force acting on the outer skin due to the space between each node ring being widened at the part located outside the bending of the curved part. It is designed not to interfere.

[0015] Preferably, the bulging portion is an annular portion in which a portion of the outer skin located in a gap portion between the node rings is bulged into an annular shape having a diameter larger than the diameter of the fitting surface of the outer skin. It is.

[0016] In the above configuration, by bulging the portion of the bulging portion of the outer skin located in the gap portion between each node ring of the bending portion into an annular shape having a diameter larger than the diameter of the fitting surface of the outer skin, As the joints of the curved part rotate, the space between the joints becomes narrower at the inner part of the bend of the curved part, and the outer skin is compressed by the force in the compression direction acting on the outer skin. At the same time, the outer skin is easily deformed in the direction of bending outward. This prevents the outer skin from invading between each node ring and being bitten.

[0017] Preferably, in the bulging portion, the wall portion of the outer skin is thinnest in the vicinity of the apex of the annular portion.

[0018] And, in the above configuration, the wall portion of the outer skin near the apex of the annular portion of the bulge By making the wall thickness the thinnest, it becomes easier to deform the bulging portion of the bending portion. As a result, the space between the node rings is narrowed at the portion located inside the bending portion of the bending portion in accordance with the rotational movement of each node ring of the bending portion, so that a force in the compression direction acts on the outer skin and the outer skin is removed. When compressed, the outer skin is easily deformed in the direction of bending outward to prevent the outer skin from intruding between each node ring. In addition, the bulging part of the outer skin can be easily extended and deformed at the part located outside the bending part of the bending part, so that the part located outside the bending part of the bending part does not stretch and obstruct the bending. Is.

[0019] Preferably, the bulging portion has a radius of curvature R1 of an arc in a cross section passing through the central axis of the outer peripheral surface of the annular portion and a cross section passing through the central axis of the inner peripheral surface of the annular portion. The relationship with the radius of curvature R2 of the arc is set to Rl> R2.

[0020] In the above configuration, the curvature radius R1 of the arc in the cross section passing through the central axis of the outer peripheral surface of the annular portion of the bulging portion and the cross section passing through the central axis of the inner peripheral surface of the annular portion. By setting the relationship with the radius of curvature R2 of the arc as Rl> R2, the outer skin of the part located between the nodal rings is thicker at the wall of the outer skin near the top of the annular part of the bulging part. Is made the thinnest, making it easier to deform the bulging part during the bending operation. As a result, the space between the joint rings is narrowed at the portion located inside the bending portion of the bending portion in accordance with the rotational movement of each bending portion of the bending portion. When compressed, the outer skin is easily deformed in the direction of bending outward, preventing the outer skin from intruding between each node ring. In addition, the bulging portion of the outer skin can easily extend and deform the portion located outside the bending portion of the bending portion, so that the portion located outside the bending portion of the bending portion does not stretch and obstruct the bending. It is a thing.

[0021] Preferably, the bulging portion changes the wall thickness of the outer skin wall for each gap portion between the node rings arranged in parallel along the insertion direction of the endoscope insertion portion, It has a wall thickness distribution that adjusts and distributes the bending resistance between each node ring.

[0022] In the above configuration, the wall thickness of the bulging portion of the outer skin is changed for each gap portion between the node rings arranged in parallel along the insertion direction of the endoscope insertion portion. In addition, by adjusting and distributing the bending resistance between each node ring, a desired shape in a curved state is provided. [0023] Preferably, the wall thickness of the outer wall of the gap between the node rings increases as the wall thickness distribution moves forward along the insertion direction of the endoscope insertion section.

[0024] In the above configuration, the wall thickness of the outer wall of the gap between the node rings increases toward the front side along the insertion direction of the endoscope insertion portion. By setting, the rear end side is more easily bent than the front end side of the bending portion.

[0025] Preferably, the wall thickness of the outer wall of the gap between the node rings becomes smaller as the wall thickness distribution moves forward along the insertion direction of the endoscope insertion section.

[0026] With the above configuration, the thickness distribution of the outer wall of the outer wall of the gap between the node rings becomes smaller as it goes forward along the insertion direction of the endoscope insertion portion. By setting, the front end side is more easily bent than the rear end side of the bending portion.

[0027] Preferably, the outer skin restricts the non-bulged portion from being displaced in the insertion direction of the endoscope insertion portion on the inner peripheral surface of the non-bulged portion fitted to the node ring. Position control means.

[0028] In the above configuration, the non-bulged portion of the outer skin is positioned in the insertion direction of the endoscope insertion portion by the position regulating means on the inner peripheral surface of the non-bulged portion of the outer skin fitted to the node ring. It is intended to regulate the deviation.

[0029] Preferably, the position restricting means forms a position restricting hole in the node ring.

The convex part which fits in the said hole is provided in the internal peripheral surface of the said non-bulged part.

[0030] In the configuration described above, the convex portion of the inner peripheral surface of the non-bulged portion is fitted into the hole for restricting the position of the node ring, whereby the non-expanded outer skin is inserted in the insertion direction of the endoscope insertion portion. It is intended to regulate the displacement of the protruding part.

[0031] Preferably, the position restricting means fits a convex portion provided on an inner peripheral surface of the non-bulged portion into a wire bending portion of the bending wire formed on the node ring. Is a thing

In the above configuration, the insertion portion of the endoscope is fitted by fitting the convex portion of the inner peripheral surface of the non-bulged portion to the bending portion for receiving the wire of the bending wire formed on the node ring. This prevents the non-bulged portion of the outer skin from being displaced in the insertion direction.

[0033] Preferably, the position restricting means is provided on the head of a pin projecting from the node ring. The concave portion provided on the inner peripheral surface of the protruding portion is fitted.

[0034] In the configuration described above, the concave portion of the inner peripheral surface of the non-bulged portion is fitted to the head portion of the pin protruding from the node ring, whereby the outer skin is inserted in the insertion direction of the endoscope insertion portion. The non-bulged part is restricted from being displaced.

[0035] According to the present invention, it is possible to prevent biting of the outer skin between the node rings when the bending portion is bent without using a protective net, and to facilitate manufacture of the endoscope insertion portion. It is possible to provide a curved portion structure of an endoscope.

Brief Description of Drawings

FIG. 1 is a schematic configuration diagram showing an overall configuration of a general endoscope to which a bending portion structure of an endoscope according to a first embodiment of the present invention is applied.

FIG. 2 is a schematic configuration diagram showing an internal configuration of a distal rigid portion of the endoscope according to the first embodiment.

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1, showing a transverse cross section of the curved portion of the endoscope according to the first embodiment.

FIG. 4 is a side view showing a state in which the node rings of the bending portion of the endoscope according to the first embodiment are juxtaposed.

FIG. 5 is a perspective view showing one node ring of the bending portion of the endoscope according to the first embodiment.

FIG. 6 is a cross-sectional view of the wire guide portion of the node ring of the bending portion of the endoscope according to the first embodiment.

FIG. 7 is a longitudinal sectional view of a main part schematically showing a state in which an outer tube is fitted to the outside of the bending tube of the bending part of the endoscope according to the first embodiment.

FIG. 8 is a longitudinal sectional view of a main part showing a bulging portion of an outer tube of a bending portion of the endoscope according to the first embodiment.

FIG. 9 is a longitudinal sectional view of a main part for explaining a deformed state of the outer tube when the bending portion of the endoscope according to the first embodiment is bent.

FIG. 10 is a longitudinal sectional view of a main part for explaining the biting state of the outer tube when the bending portion of the endoscope according to the first embodiment is bent. [FIG. 11A] FIG. 11A is a longitudinal sectional view of an essential part schematically showing a bending part of an endoscope according to a second embodiment of the present invention.

[FIG. 11B] FIG. 11B is a longitudinal sectional view of an essential part schematically showing a curved part of an endoscope according to a third embodiment of the present invention.

[FIG. 11C] FIG. 11C is a longitudinal sectional view of an essential part schematically showing a bending part of an endoscope according to a fourth embodiment of the present invention.

FIG. 12 is a longitudinal cross-sectional view of a main part showing a bending portion of an endoscope according to a fifth embodiment of the present invention.

FIG. 13 is a longitudinal sectional view of a main part showing a bulging portion of an outer tube of a bending portion of an endoscope according to a fifth embodiment.

FIG. 14 is a longitudinal sectional view of an essential part showing a curved part of an endoscope according to a sixth embodiment of the present invention.

[FIG. 15A] FIG. 15A is a longitudinal sectional view of an essential part showing a bending portion of an endoscope according to a seventh embodiment of the present invention.

[FIG. 15B] FIG. 15B is a longitudinal sectional view of a main part showing a bending portion of an endoscope according to an eighth embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an example of a flexible endoscope 1 such as a colonoscope to which the bending portion structure of the endoscope of this embodiment is applied. The endoscope 1 has a long and narrow insertion portion 2 inserted into the body and an operation portion 3 connected to the proximal end side of the insertion portion 2. A main body 2A of the insertion portion 2 has an elongated flexible tube portion 4, a bending portion 5, and a distal end rigid portion 6. The bending portion 5 has a proximal end connected to the distal end of the flexible tube portion 4. The distal end rigid portion 6 is connected at the proximal end to the distal end of the bending portion 5. The bending portion 5 can be bent as shown by a solid line or a two-dot chain line in FIG. 1 from a normal straight line extending straight as shown by a one-dot chain line in FIG.

[0038] On the distal end surface of the distal rigid portion 6, as shown in FIG. 2, the illumination lens 7 of the illumination optical system, the objective lens 8 of the observation optical system, the distal opening 9a of the treatment instrument penetration channel 9, Not shown A nozzle for supplying air is provided.

[0039] The distal end portion of the light guide fiber 10 is fixed to the distal end rigid portion 6 behind the illumination lens 7. An imaging element 11 such as a CCD and its connection circuit board 12 are fixed behind the objective lens 8. It should be noted that the distal end portion of an image guide fiber (not shown) may be fixed in place of the image sensor 11, and the endoscope 1 may be a fiber scope without being limited to an electronic scope. The distal end rigid portion 6 includes a distal end portion of the treatment instrument passing channel 9, an air supply tube 13 (see FIG. 3) connected to an air supply / water supply nozzle, and a distal end portion of the water supply tube 14 (see FIG. 3). Etc. are fixed.

[0040] The built-in portion of the insertion portion 2 in which each distal end portion is fixed to the distal end rigid portion 6 described above, that is, as shown in Fig. 3, the light guide fiber 10 and the cable 15 such as the signal line of the image sensor 11 or In the case of a fiberscope, an image guide fiber (not shown), a treatment instrument tunable channel 9, an air supply tube 13, a water supply tube 14, etc. pass from the inside of the bending portion 5 to the inside of the flexible tube portion 4, and the flexible tube. It extends to the base end side of part 4.

In addition, the operation unit 3 is connected to the proximal end portion of the flexible tube unit 4. The operating unit 3 is provided with a gripping part 17 that is held by an operator. A base end portion of a universal cord 18 is connected to the grip portion 17. A connector portion 19 is connected to the distal end portion of the universal cord 18. The connector unit 19 is connected to a light source device (not shown) or a video processor.

[0042] Further, the operation section 3 includes an up / down bending operation knob 20 and a left / right bending operation knob 21 for bending the bending section 5, a suction button 22, an air / water supply button 23, and endoscopic photography. Various switches 24 and a treatment instrument insertion section 25 are provided. The treatment instrument insertion portion 25 is provided with a treatment instrument insertion inlet 26. The treatment instrument penetrating inlet 26 is connected to a proximal end portion of the treatment instrument penetrating channel 9 disposed in the insertion section 2. An endoscope treatment tool (not shown) is inserted into the treatment instrument insertion channel 9 from the treatment instrument entry 26 of the endoscope 1 and pushed into the distal rigid portion 6 side. Thereafter, the treatment instrument piercing channel 9 is projected outward from the front end opening 9a.

Further, as shown in FIG. 7, the bending portion 5 of the present embodiment includes a bending tube 30 and an outer tube 38 to be described later. The bending tube 30 has a plurality of node rings 31. Multiple as shown in Figure 4 The node rings 31 are juxtaposed along the insertion direction (axial direction) of the insertion portion 2 of the endoscope 1. The front and rear node rings 31 are connected to each other so as to be rotatable around a rivet (support shaft portion) 35 described later. The outer tube 38 is formed of an elastic material in a cylindrical shape, and is directly fitted on the outer periphery of the bending tube 30. As a result, the entire outer surface of the bending portion 5 is covered with the outer tube 38.

As shown in FIG. 5, each node ring 31 has a cylindrical node ring body 32. At the front end of the node ring body 32, two projecting pieces 33 are arranged at positions 180 ° apart in the circumferential direction. The two projecting pieces 33 are formed such that a part of the outer peripheral surface of the node ring main body 32 projects forward. At the rear end of the node ring main body 32, two projecting pieces 34 are disposed at positions 180 degrees apart in the circumferential direction. Here, the front two projecting pieces 33 and the rear two projecting pieces 34 are arranged at positions shifted by 90 ° in the circumferential direction. Further, the two rear projecting pieces 34 are formed such that a part of the outer peripheral surface of the node ring main body 32 protrudes rearward and a step corresponding to the substantially plate thickness of the front projecting piece 33 is provided. Les.

[0045] A plurality of node rings 31 arranged side by side in the bending portion 5 are connected so as to be rotatable as follows. Here, the two projecting pieces 34 on the rear side of the front node ring 31 and the two projecting pieces 33 on the front side of the rear node ring 31 are overlapped (hereinafter referred to as polymerization) to form a superposed portion. It is formed. A through hole is formed in the overlapped portion, and a rivet is inserted into the hole formed in each of the projecting pieces 33 and 34. In this state, the rivets are caulked to connect the plurality of node rings 31 via the rivets 35. As a result, the front node ring 31 and the rear node ring 31 are pivotally supported around the rivet 35. Between these, a support shaft portion with the rivet 35 as a rotation support shaft is formed.

[0046] Further, at the rear end portion of the distal end hard portion 6, two projecting pieces 6a protrude rearward. The two projecting pieces 33 on the front side of the node ring 31 at the foremost end position of the curved portion 5 are overlapped with the two projecting pieces 6a in the same manner to form a superposed portion. A through hole is formed in this overlapped portion, and a rivet is inserted into the hole formed in each of the projecting pieces 33 and 6a. In this state, the rivet is caulked to be connected via the rivet 35 and pivotally supported around the rivet 35.

[0047] Further, the cylindrical connecting member 4a disposed at the tip position of the flexible tube portion 4 has two protruding pieces. Each 4al protrudes forward. The two projecting pieces 34 on the rear side of the node ring 31 at the rearmost end position of the curved portion 5 are overlapped with the two projecting pieces 4al, respectively, to form a superposed portion. A through hole is formed in this overlapping portion, and a rivet is inserted into the hole formed in each of the projecting pieces 34 and 4al. In this state, the rivets are caulked to be connected via the rivets 35, and are pivotally supported around the rivets 35.

[0048] Then, in the bending portion 5 of the present embodiment, the orientation of the rivets 35 that serve as the pivot shafts that respectively connect the plurality of node rings 31 is shifted by 90 ° between the front and rear of each node ring 31. Are arranged alternately. As a result, the entire bending portion 5 can be bent in four directions, up and down and left and right.

In addition, as shown in FIGS. 3 and 6, four operation wires (bending wires) 36 are disposed in the bending portion 5. The four operation wires 36 bend the entire bending portion 5 in four directions, up and down and left and right. The distal end portions of these four operation wires 36 are fixed to the rear end portion of the distal end rigid portion 6. A concave portion 6b is formed at the rear end portion of the distal end hard portion 6 by projecting inwardly a part of the distal end side peripheral wall portion corresponding to the projecting piece 6a by pressing. The concave portion 6b of the distal end hard portion 6 is engaged in a state where the distal end portion of the operation wire 36 is inserted, and the engagement portion is brazed with silver to fix the operation wire 36. The recesses 6b are formed at four locations in a state shifted by 90 ° in the circumferential direction. The tip of the operation wire 36 may be fixed to a recess (not shown! /) Formed in the node ring 31 at the foremost end position.

[0050] Further, two wire guides (wire receivers) 37 are formed inwardly on the peripheral wall portion of the node ring main body 32 of each node ring 31, as shown in FIG. Each wire guide 37 is projected and cut and raised while part of the peripheral wall portion of the node ring main body 32 is cut and bent from the outer peripheral surface side toward the inner peripheral surface side by pressing. Then, either one of the operation wire 36 in the vertical direction or the operation wire 36 in the horizontal direction is passed through these wire guides 37.

[0051] In addition, each base end portion of the vertical operation wire 36 and the horizontal operation wire 36 extends from the inside of the curved portion 5 to the inside of the flexible tube portion 4 and extends into the operation portion 3. . In the operation section 3, a vertical bending operation mechanism (not shown) and a horizontal bending operation mechanism (not shown) are arranged. The vertical bending operation mechanism is controlled by the vertical bending operation knob 20. Driven. The left / right bending operation mechanism is driven by a left / right bending operation knob 21. The base end portion of the vertical operation wire 36 is connected to the vertical bending operation mechanism. Similarly, the proximal end portion of the left and right operation wire 36 is connected to the left and right bending operation mechanism. The operation wires 36 are pulled and driven in accordance with the turning operation of the up / down bending operation knob 20 and the left / right bending operation knob 21. As a result, the bending portion 5 can be remotely operated from a normal linear state (non-curved state) with a straightly extending bending angle of 0 ° to a curved shape that is bent to an arbitrary bending angle in the vertical and left-right directions. It has become to be done.

[0052] The outer tube 38 is injection-molded into a cylindrical shape by an elastic material made of a thermoplastic elastomer (such as styrene, olefin, or urethane). When the outer tube 38 is formed, as shown in FIG. 7, a bulging portion (bite) is formed in the portion located in the gap S between the nodes 31 along the insertion direction of the insertion portion 2 of the endoscope 1. 39) is formed. The bulging portion 39 is formed by connecting the portion of the outer tube 38 positioned in the gap S between the node rings 31 to the fitting surface 40a of the non-bulged portion 40 of the outer tube 38 fitted to each node ring 31. An annular portion bulged in a lantern shape (barrel shape) with a diameter larger than the inner diameter d1. In the present embodiment, as shown in FIG. 8, the wall thickness tl of the bulging portion 39 of the outer tube 38 is formed substantially constant over the entire arc surface of the outer peripheral surface 39a of the annular portion of the lantern. Has been.

[0053] In the present embodiment, the outer diameter of the node ring 31 is set to 10 mm, for example, and the inner diameter of the non-bulged portion 40 before the outer tube 38 is fitted is set to 9 mm, for example. Further, the wall thickness t2 of the non-bulged portion 40 of the outer tube 38 is 0.6 mm, for example, and the wall thickness tl of the bulged portion 39 is 0.3 mm, for example, and is set to a constant radius of curvature R. In addition, one of the following two methods is used as a method of releasing the molded product (outer tube) from the mold (nesting) for molding the outer tube 38. The first method enlarges the diameter of the outer tube by making the outer space of the outer tube a sealed space and making the sealed space vacuum. The second method enlarges the diameter of the outer tube by pressurizing the inner space of the outer tube with the inner space being sealed.

Next, the operation of the above configuration will be described. When the endoscope 1 of the present embodiment is used, it is accompanied by the turning operation of the up / down bending operation knob 20 and the left / right bending operation knob 21 of the operation unit 3. Each operating wire 36 is pulled and driven. As a result, the bending portion 5 is remotely operated to bend from a normal linear state (non-curved state) with a straightly extending bending angle of 0 ° to a curved shape that is bent to an arbitrary bending angle in the vertical and horizontal directions. The

[0055] During the bending operation of the bending portion 5, as shown in FIG. 9, in the portion located outside the bending portion of the bending portion 5, the gap portion between the node rings 31 in accordance with the rotational movement of each node ring 31. The interval of S increases. As a result, a tensile force acts on the outer tube 38 and the bulged portion 39 of the outer tube 38 is elastically deformed and extended. At the same time, in the portion located inside the bend of the bending portion 5, the gap S between the node rings 31 is narrowed. Thereby, a force in the compression direction acts on the bulging portion 39 of the outer tube 38. At this time, the bulging portion 39 of the outer tube 38 is elastically deformed in the direction of bending outward by the action of the force in the compression direction. As a result, in this embodiment, the bulging portion 39 of the outer tube 38 is elastically deformed in the direction of bending outward at the portion located inside the bending portion 5 of the bending portion 5 as the node ring 31 rotates. The At this time, it is possible to prevent the outer tube 38 from being bitten between the node rings 31 of the bending tube 30 as shown in FIG. 10 at a portion where the gap S between the node rings 31 becomes narrow.

[0056] Therefore, the above configuration has the following effects. That is, in the present embodiment, the bulging portion 39 is provided at a portion located in the gap portion S between the node rings 31 in the axial direction of the outer tube 38 of the bending portion 5. The bulged portion 39 is bulged in a substantially lantern shape with a diameter larger than the diameter dl of the fitting surface 40a of the non-bulged portion 40 of the outer tube 38 fitted to each node ring 31. . As a result, the portion of the bulging portion 39 of the outer tube 38 positioned inside the bending portion 5 in the bent state is elastically deformed into a state where it can be easily bent outward without entering between the node rings 31. . For this reason, the outer tube 38 is not bitten between the node rings 31 located inside the bending portion 5. Furthermore, since it can be easily extended and deformed outside the bending of the bending portion 5, the portion located outside the bending of the bending portion 5 does not stretch and obstruct the bending operation of the bending portion 5.

Therefore, in the present embodiment, the outer tube 38 between the node rings 31 at the time of bending of the bending portion 5 in which the protective net is not interposed between the node ring 31 and the outer tube 38 as in the prior art. Biting can be prevented. Therefore, the insertion portion 2 of the endoscope 1 can be easily manufactured as compared with the conventional case where a protective net is interposed between the node ring 31 and the outer tube 38. [0058] FIG. 11A shows a second embodiment of the present invention. In the present embodiment, the configuration of the bending portion 5 of the endoscope 1 of the first embodiment (see FIGS. 1 to 10) is changed as follows.

That is, in the present embodiment, the position restricting means 41 is provided on the inner peripheral surface of the non-bulged portion 40 of the outer tube 38 fitted to the node ring 31. The position restricting means 41 restricts the non-bulged portion 40 from being displaced in the inserting direction of the inserting portion 2 of the endoscope 1. The position restricting means 41 is formed by forming a position restricting hole 42 in the node ring 31 and providing a convex portion 38b that fits (fits) in the hole 42 on the inner peripheral surface of the non-bulged portion 40. It is.

Therefore, in the present embodiment, since the position restricting means 41 is provided in which the convex portion 38b of the non-bulged portion 40 is fitted in the hole 42 of the node ring 31, the outer tube 38 when the bending portion 5 is bent is provided. It is possible to prevent the non-bulged portion 40 from being displaced in the insertion direction of the insertion portion 2 of the endoscope 1. Therefore, it is possible to stably perform the bending operation of the curved portion 5 in which the non-bulged portion 40 is not likely to be bitten into the gap portion S between the node rings 31.

FIG. 11B shows a third embodiment of the present invention. In the present embodiment, the configuration of the position restricting means 41 of the non-bulged portion 40 of the outer tube 38 of the second embodiment (see FIG. 11A) is changed as follows.

That is, in the present embodiment, the non-bulged portion 40 of the outer tube 38 is formed in the opening 37a of the bent portion for the wire guide (wire receiver) 37 of the bending wire formed in the node ring 31. The convex portions 38b provided on the inner peripheral surface are fitted together (hereinafter referred to as fitting).

[0063] Therefore, in the present embodiment, the position restricting means 41 is provided in which the convex portion 38b of the non-bulged portion 40 of the outer tube 38 is fitted into the opening portion 37a for the wire guide 37 of the node ring 31. Therefore, it is possible to prevent the non-bulged portion 40 of the outer tube 38 from being displaced in the insertion direction of the insertion portion 2 of the endoscope 1 when the curved portion 5 is bent. Therefore, also in the present embodiment, it is possible to stably perform the bending operation of the bending portion 5 as in the second embodiment. Furthermore, in the present embodiment, the convex portion 38b of the non-bulged portion 40 of the outer tube 38 is fitted using the opening 37a for the wire guide 37 of the node ring 31. Thereby, it is not necessary to provide a special configuration for the position regulating means 41. Therefore, the force S can be used to simplify the configuration of the bending portion 5 of the endoscope 1. [0064] FIG. 11C shows a fourth embodiment of the present invention. In this embodiment, the configuration of the position restricting means 41 of the non-bulged portion 40 of the outer tube 38 in the second embodiment (see FIG. 11A) is changed as follows.

That is, in the present embodiment, a pin 43 for position regulation projects from the node ring 31 and protrudes.

In addition, the inner peripheral surface of the non-bulged portion 40 of the outer tube 38 is provided with a recess 44 that fits into the head of the pin 43.

[0066] Therefore, in the present embodiment, the position restricting means 41 is provided in which the concave portion 44 of the non-bulged portion 40 of the outer tube 38 is fitted to the position restricting pin 43 of the node ring 31. It is possible to prevent the non-bulged portion 40 of the outer tube 38 from being displaced in the insertion direction of the insertion portion 2 of the endoscope 1 at the time of bending of 5. Therefore, also in the present embodiment, the bending operation of the bending portion 5 can be stably performed as in the second embodiment.

FIG. 12 and FIG. 13 show a fifth embodiment of the present invention. In the present embodiment, the configuration of the bending portion 5 of the endoscope 1 of the first embodiment (see FIGS. 1 to 10) is changed as follows.

That is, in the present embodiment, as shown in FIG. 13, the bulging portion 39 of the outer tube 38 has a radius of curvature Rl (Ro of the outer peripheral surface 39a of the annular portion bulged substantially in the shape of a lantern. And the radius of curvature R2 (corresponding to Ri) of the arc of the inner peripheral surface 39b of the annular part is set to ¾1> R2. As a result, the bulging portion 39 of the outer tube 38 is formed so that the wall thickness t of the outer tube 38 is the thinnest in the vicinity of the apex of the annular portion.

[0069] It should be noted that the radius of curvature of the arc at the radius of curvature R1 of the arc of the outer peripheral surface 39a and the radius of curvature R2 of the arc of the inner peripheral surface 39b is the radius of curvature of each arc in the longitudinal section passing through the central axis of the annular portion. .

Therefore, in the present embodiment, the relationship between the radius of curvature R1 of the outer circumferential surface of the annular portion of the bulging portion 39 of the outer tube 38 and the radius of curvature R2 of the circular arc of the inner circumferential surface of the annular portion is expressed as follows. Since R1> R2, the outer tube 38 in the portion located in the gap S between the node rings 31 has the wall thickness of the outer tube 38 in the vicinity of the top of the annular portion of the bulging portion 39. Can be thin. Therefore, the portion of the bulging portion 39 during the bending operation of the bending portion 5 Can be made easier. As a result, when the bending operation of the bending portion 5 is performed, the space S between the node rings 31 is narrowed at the portion located inside the bending of the bending portion 5 due to the rotation of each node ring 31. When the outer tube 38 is compressed by applying a force in the compression direction to the outer tube 38, the outer tube 38 can be easily deformed in a direction to bend inward of the bending of the bending portion 5. Therefore, it is possible to prevent the outer tube 38 from being invaded between the nodes 31 and being bitten. Further, since the bulging portion 39 of the outer tube 38 can be easily extended and deformed at the portion located outside the bending portion of the bending portion 5, the portion located outside the bending portion of the bending portion may be stretched to inhibit the bending. Absent.

[0071] Further, the following Table 1 shows that the bending portion 5 is bent when a plurality of types of outer tube 38 having different shapes are attached to each node ring 31 of the bending tube 30 of the bending portion 5 having the standard shape. The experimental result of the experiment confirming the difference in the deformation state of the outer skin plate 38 is shown.

[table 1]

[0072] Here, each node ring 31 of the bending tube 30 of the bending portion 5 having the standard shape is set as shown in FIG. That is, the outer diameter dimension D of each node ring 31 is 12 mm, the length dimension X of the insertion portion 2 of the node ring body 32 in the insertion direction is 2.7 mm, and the gap S between two adjacent node rings 31 in the front and rear direction S The length dimension Y is 3. Omm.

[0073] Further, as shown in FIG. 13, the shape and dimensions of the outer tube 38 are: inner diameter: d, wall thickness: t, width of the straight portion (non-bulged portion 40) of the outer shell 38: A, bulged portion The width of 39 is B, the radius of the inner peripheral surface of the bulging portion 39 is Ri, and the radius of the outer peripheral surface of the bulging portion 39 is Ro. In Table 1, the unit of length is m m.

[0074] In Table 1, the comparison pattern (1) shows that the inner diameter d of the non-bulged portion 40 of the outer tube 38 is the reference dimension d = 10 mm (reference) and the change 1 is larger than the reference dimension. The experimental results are shown for the case (d = reference dimension + 2 mm) and for change 2 (d = reference dimension-2 mm) smaller than the reference dimension. Here, in the case of the change 1 in which the inner diameter d of the non-bulged portion 40 of the outer tube 38 is made larger than the reference dimension (other dimensions are the same as the reference dimension), the non-expanded of the outer tube 38 The amount of tightening when the protruding portion 40 is fitted to the outer peripheral surface of the node ring body 32 becomes loose, and in the case of the change 2 in which the inner diameter d of the non-bulged portion 40 of the outer tube 38 is made smaller than the reference dimension, the outer tube The amount of tightening when the non-bulged portion 40 of 38 is fitted to the outer peripheral surface of the node ring body 32 becomes tight.

[0075] The comparison pattern (2) is for the case where the radius of the outer peripheral surface of the bulging portion 39 of the outer tube 38 is Ro and the radius of the inner peripheral surface is Ri: Ro = 3 mm and Ri = 2 mm (reference) In the case of change 3 (Ro = 4mm, Ri = 3mm), which was made larger than the reference dimension, and in case of change 4 (Ro = 2mm, Ri = 7mm), which was made smaller than the reference dimension, respectively. The experimental results are shown.

[0076] Comparative pattern (3) shows that the radius of the inner peripheral surface of the bulging portion 39 of the outer tube 38: Ri is fixed to the reference dimension Ri = 2mm, and the outer peripheral radius: Ro is the reference dimension Ro. = 3mm (reference), change 5 larger than the reference dimension (Ro = 3.5mm), and change 6 smaller than the reference dimension (Ro = 2mm) Experimental results are shown.

[0077] As is clear from the experimental results of the comparative pattern (1) in Table 1 above, when the non-bulged portion 40 of the outer skin tube 38 is fitted to the outer peripheral surface of the node ring main body 32 as in Modification 2. When the tightening amount is tight, the deformed state of the outer tube 38 when the bending portion 5 is bent is the direction where the bulging portion 39 of the outer tube 38 is bent outward at the portion located inside the bending portion 5 of the bending portion 5. It will become elastically deformed. Therefore, in this case, the outer tube 38 may be bitten between the node rings 31 of the bending tube 30 (see FIG. 10). Similarly, when the wall thickness of the bulging portion 39 of the outer tube 38 is too thin as shown in change 5 of the comparison pattern (3) in Table 1 above, the outer tube 38 is bitten between the nodes 31 of the bending tube 30 in the same manner. (See Figure 10).

[0078] Also, when the tightening amount when the non-bulged portion 40 of the outer tube 38 is fitted to the outer peripheral surface of the node ring main body 32 as shown in Modification 1 of the comparison pattern (1) in Table 1 above is loose. , Bending of the bending part 5 The bending resistance at the time increases. Similarly, when the curvature of the non-bulged portion 40 of the outer tube 38 is too slow as in the change 3 of the comparison pattern (2), the bending resistance when the bending portion 5 is bent increases. Further, when the thickness of the non-bulged portion 40 of the outer tube 38 is increased as in the change 6 of the comparison pattern (3), the bending resistance when the bending portion 5 is bent increases.

[0079] Fig. 14 shows a sixth embodiment of the present invention. In this embodiment, the configuration of the outer tube 38 of the first embodiment (see FIGS. 1 to 10) is changed as follows.

That is, in the present embodiment, the bulging portion 39 of the outer tube 38 is provided for each gap portion S between the node rings 31 arranged in parallel along the insertion direction of the insertion portion 2 of the endoscope 1. The wall thickness of the bulging portion 39 of the outer tube 38 is changed. As a result, a thickness distribution is obtained in which the bending resistance of the gap S between the node rings 31 is adjusted and distributed. The thickness distribution of the bulging portion 39 of the outer tube 38 in FIG. 14 is, for example, the gap between the node rings 31 according to the forward force along the insertion direction of the insertion portion 2 of the endoscope 1 and accordingly. Wall thickness of the outer sheath tube of S T force S decreases. Here, the thickness T at the apex position of the bulging portion 39 of the outer tube 38 is set to satisfy the relationship of T1 <T2 <T3 from the front side along the insertion direction of the insertion portion 2 of the endoscope 1. Note that T1 = 0.2 mm, T2 = 0.35 mm, and T3 = 0.5 mm.

[0081] In addition, the thickness distribution of the bulging portion 39 of the outer tube 38 is such that the gap S between the node rings 31 is directed to the front side along the insertion direction of the insertion portion 2 of the endoscope 1 and accordingly. A wall thickness T of the outer tube 38 may be increased.

[0082] In the case of the above configuration, the outer tube 38 bulges for each gap S between the node rings 31 arranged in parallel along the insertion direction of the insertion portion 2 of the endoscope 1. By changing the wall thickness of the wall portion 39, it is possible to adjust and distribute the bending resistance between the node rings 31 when the bending portion 5 is bent. Thereby, a desired shape in a bent state is given when the bending portion 5 is bent.

[0083] Furthermore, the wall thickness of the wall portion of the outer tube 38 in the gap S between the node rings 31 is reduced according to the forward force along the insertion direction of the insertion portion 2 of the endoscope 1, and accordingly By setting the thickness distribution, the front end side is more easily bent than the rear end side of the curved portion 5. In addition, the force applied to the front side along the insertion direction of the insertion portion 2 of the endoscope 1 and the outside of the gap S between the node rings 31 according to the direction of force. By setting the thickness distribution such that the wall thickness of the skin tube 38 is increased, the rear end side is more easily bent than the front end side of the bending portion 5.

Therefore, in the case of the above configuration, the outer tube 38 bulges for each gap S between the node rings 31 arranged in parallel along the insertion direction of the insertion portion 2 of the endoscope 1. By changing the wall thickness of the wall portion 39, the bending resistance of the gap portion S between the node rings 31 is adjusted and distributed. Can be applied with a desired distribution in the axial direction. As a result, it is possible to provide a positive curve motion and a curved shape that are desirable when the bending portion 5 is bent.

[0085] FIG. 15A shows a seventh embodiment of the present invention. In the present embodiment, the configuration of the bending portion 5 of the endoscope 1 of the first embodiment (see FIGS. 1 to 10) is changed as follows.

That is, in the present embodiment, as shown in FIG. 15A, the bulging portion 39 of the outer tube 38 is formed so that the cross-sectional shape of the annular portion bulged substantially in a lantern shape is bent in an L shape. It has an L-shaped bend 61.

[0087] Therefore, the above configuration has the following effects. That is, in the present embodiment, the L-shaped bent portion 61 is provided in the portion of the bulging portion 39 located in the gap portion S between the node rings 31 in the axial direction of the outer tube 38 of the bending portion 5. . As a result, the L-shaped bent portion 61 of the bulging portion 39 of the outer tube 38 located inside the bent portion 5 in the bent state can be easily bent outward without entering between the node rings 31. It does not bite due to elastic deformation. Furthermore, since it can be easily stretched and deformed outside the bending portion 5, the portion located outside the bending portion 5 does not stretch and does not hinder the bending operation of the bending portion 5.

Therefore, also in the present embodiment, in the same way as in the first embodiment, when the bending portion 5 is bent without a protective net interposed between the node ring 31 and the outer tube 38 as in the prior art. Biting of the outer tube 38 between the node rings 31 can be prevented. Therefore, the insertion portion 2 of the endoscope 1 can be easily manufactured as compared with the conventional case where a protective net is interposed between the node ring 31 and the outer tube 38.

[0089] FIG. 15B shows an eighth embodiment of the present invention. This embodiment is the first The configuration of the bending portion 5 of the endoscope 1 according to the embodiment (see FIGS. 1 to 10) is changed as follows.

That is, in the present embodiment, the outer peripheral surface of the outer tube 38 is formed by the flat peripheral surface 71 having no irregularities. Further, on the inner peripheral surface of the outer tube 38, a ring-shaped recess 72 is formed at a portion located in the gap S between the node rings 31 along the insertion direction of the insertion portion 2 of the endoscope 1. Yes. Then, the outer tube that is fitted to the node ring 31 by a thin portion 73 between the flat circumferential surface 71 on the outer peripheral surface of the outer tube 38 and the ring-shaped recess 72 on the inner peripheral surface of the outer tube 38. A bulging portion (biting prevention portion) bulging larger than the diameter of the fitting surface 40a of 38 is formed.

[0091] In the present embodiment, when the bending portion 5 is bent, the interval between the node rings 31 is widened at the portion located outside the bending of the bending portion 5 with the turning operation of each node ring 31. As a result, a tensile force acts on the outer tube 38 and the outer tube 38 expands, and the space between the node rings 31 becomes narrower at the portion located inside the bent portion 5, thereby compressing the outer tube 38. Directional force acts to compress the outer skin. At this time, when a force in the compression direction is applied to the outer tube 38 at a portion where the interval between the node rings 31 is narrow, a portion of the thin portion 73 of the outer tube 38 located in the gap S between the node rings 31. The outer tube 38 is deformed in the direction of bending outward. As a result, the outer tube 38 is prevented from intruding between the node rings 31 and being bitten. Furthermore, since the thin wall portion 73 of the outer tube 38 can easily extend and deform the portion located outside the bent portion of the curved portion 5, the portion located outside the bent portion of the curved portion 5 is stretched to inhibit the bending. There is no.

Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

Next, other characteristic technical matters of the present application are appended as follows.

Record

(Additional Item 1) An endoscope bending portion in which an elastic cylindrical outer skin is directly fitted on the outer periphery of the bending tube to which the node rings are connected, and is a portion of the portion positioned between the node rings in the axial direction of the outer skin. At least an inner peripheral surface has an outer skin provided with a bulging portion that bulges out in an annular shape (axisymmetric) from an inner peripheral surface of a portion that directly fits into a node ring. (Additional Item 2) The endoscope bending portion according to Additional Item 1, wherein the bulged portions of the outer skin are thinner than the non-bulged portions on both sides thereof.

(Additional Item 3) The endoscope bending portion according to Additional Item 1, wherein the wall thickness of the bulged portion of the outer skin is the thinnest in the vicinity of the bulge apex.

(Additional Item 4) The endoscope bending portion according to Additional Item 1, wherein the bulged portion of the outer skin has a thickness distribution that distributes a predetermined bending resistance between the nodal rings.

(Additional Item 5) A method of manufacturing an endoscope bending portion, in which the outer skin is manufactured by injection molding of an elastic material with an allowance for deformation in advance so that the outer skin has a predetermined shape when fitted to the node ring.

Industrial applicability

The present invention is effective in the technical field of manufacturing a bending portion of an endoscope in which a bending portion that can be bent is disposed at the distal end portion of the insertion portion inserted into the body.

Claims

The scope of the claims

[1] A curved tube in which a plurality of node rings are arranged in parallel along the insertion direction of the endoscope insertion part, and the front and rear node rings are connected to each other so as to be rotatable around a support shaft part, and elastic A bending portion that is formed in a cylindrical shape with a material and has an outer skin that is directly fitted on the outer periphery of the bending tube, and is configured to bend the bending portion as the node ring rotates in the bending tube. A curved structure of an endoscope,

The outer skin has a biting prevention portion at a portion located in a gap portion between the node rings along the insertion direction of the endoscope insertion portion,

The biting prevention part deforms the outer skin in a direction in which the outer skin is bent outward at a portion located on the inner side of the bending of the bending part during the rotation operation of each of the bending parts of the bending part. Endoscopic bending structure that prevents the outer skin from being bitten in between

Λ &.

[2] The biting prevention unit fits at least an inner peripheral surface of a portion of the outer skin located in a gap portion between the node rings along the insertion direction of the endoscope insertion part to the node ring. 2. The bending portion structure of an endoscope according to claim 1, wherein the bending portion structure is a bulging portion bulged to a diameter larger than the diameter of the fitting surface of the outer skin.

[3] The bulging portion according to claim 2, wherein the bulging portion is thinner than a thickness of a wall portion of the outer skin of a non-bulging portion formed by a fitting portion of the outer skin fitted to the node ring. Endoscope bending structure.

[4] The bulging portion is an annular portion obtained by bulging the portion of the outer skin located in the gap portion between the node rings into an annular shape having a diameter larger than the diameter of the fitting surface of the outer skin. Item 2. The bending structure of an endoscope according to Item 2.

5. The endoscope bending portion structure according to claim 2, wherein the wall portion of the outer skin is thinnest in the vicinity of the apex of the annular portion.

[6] The bulging portion includes the radius of curvature R1 of the arc in the cross section passing through the central axis of the outer peripheral surface of the annular portion and the radius of curvature of the arc in the cross section passing through the central axis of the inner peripheral surface of the annular portion. 5. The bending portion structure of an endoscope according to claim 4, wherein the relationship with R2 is set to R1> R2.

[7] The bulging portion changes the wall thickness of the outer skin wall for each gap between the joint rings arranged in parallel along the insertion direction of the endoscope insertion section, and 3. The bending portion structure of an endoscope according to claim 2, wherein the bending portion structure has a wall thickness distribution in which the bending resistance is adjusted and distributed.

8. The wall thickness distribution according to claim 7, wherein the wall thickness of the outer wall of the gap between the node rings increases in the thickness distribution toward the front side along the insertion direction of the endoscope insertion portion. Endoscope bending part structure.

9. The wall thickness distribution according to claim 7, wherein in the wall thickness distribution, the wall thickness of the outer wall of the gap between the node rings decreases toward the front side along the insertion direction of the endoscope insertion portion. Endoscope bending part structure.

[10] The position restriction for restricting displacement of the non-bulged portion in the insertion direction of the endoscope insertion portion on the inner peripheral surface of the non-bulged portion fitted to the node ring. The bending portion structure of an endoscope according to claim 3, further comprising means.

[11] The position restricting means includes a position restricting hole formed in the node ring, and a convex portion that fits into the hole on the inner peripheral surface of the non-bulged portion. The bending portion structure of an endoscope according to 1.

[12] The position restricting means is configured to fit a convex portion provided on an inner peripheral surface of the non-bulged portion into a bent portion for receiving a wire of the bending wire formed on the node ring. The bending part structure of an endoscope according to claim 10.

13. The internal view according to claim 10, wherein the position restricting means is configured to fit a concave portion provided on an inner peripheral surface of the non-bulged portion to a head portion of a pin protruding from the node ring. Mirror bending structure.