JP2011160966A - Bending mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the bending performance of a bending tube part in a bending mechanism. <P>SOLUTION: The bending mechanism includes: a front end part 6; the bending tube part 5 having a plurality of turnably connected link members 24 and connected to the front end part 6 at one end side; an operation wire 26 connected to the front end part 6 at one end, for bending the bending tube part 5 by being moved forward and backward inside the bending tube part 5; and a core member 10 inserted into the inside of the bending tube part 5, for resisting the bending of the bending tube part 5. Each of the plurality of link members 24 has a wire insertion hole 24f for inserting the operation wire 26 so as to move it forward and backward, and a front end side guide hole 24h and proximal end side guide hole 24i for positioning the insertion position of the core member 10 within a cross section orthogonal to the axis O of the bending tube part 5 and holding the core member 10 slidably in an axial direction. In the core member 10, rigidity is increased from one end side to the other end side of the bending tube part 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bending mechanism. For example, the present invention relates to a bending mechanism that performs a bending operation by moving an operation wire back and forth.

2. Description of the Related Art Conventionally, for example, devices such as manipulators and endoscopes are provided with a bending tube at the end of the manipulator or at the distal end side of the endoscope, and are provided with a bending mechanism that is bent by operating the bending tube with an operation wire. .
For example, Patent Literature 1 discloses an insertion portion having a bending tube portion and a flexible tube portion that rotatably connect a plurality of bending pieces that can be bent by advancing and retreating a tip constituent portion and an angle wire, And an operation portion provided with an angle knob for operating the angle wire connected to the base end side, the angle wire being inserted into the insertion portion, and the distal end portion of which is the proximal end portion. The endoscope is connected to each of the angle knobs, and is inserted into a guide ring disposed in the plurality of bending pieces, and one end is connected to the distal end constituting portion and the other end is connected to the proximal end portion of the bending tube. The endoscope is characterized by comprising a super elastic metal wire stretched in the bent tube portion in parallel with the angle wire.
In the endoscope of Patent Document 1, when the angle wire (operation wire) is pulled by the proximal end portion of the bending tube, the bending tube is bent according to the pulling amount of the angle wire. The elastic metal wire is curved. When the pulling of the angle wire is stopped and the angle wire is drawn out into the bending tube, the restoring force of the superelastic metal wire (core member) acts on the bending tube, thereby returning the bending tube to a straight state before bending. It is like that.

Japanese Patent No. 2753279

However, the conventional bending mechanism as described above has the following problems.
In the conventional bending mechanism, a plurality of bending pieces constituting the bending tube are rotatably connected. However, since the amount of rotation of each bending piece when the operation wire is pulled varies, the inclination of the end of the bending tube is inclined. There is a problem that the angle varies.
In the technique described in Patent Document 1, since the superelastic metal wire is inserted into the bending tube as a core member, the bending shape of the bending tube is corrected to some extent along the bending deformation of the core member. Variations can be reduced. Further, when the pulling of the operation wire is released, the straight state before bending is reproduced.
However, in the bending mechanism of Patent Document 1, when the operation wire is pulled to the proximal end side by a certain amount and the bending tube is bent, the operation wire receives a frictional force from the bending piece. The change in the length of the operation wire is larger toward the proximal end side and smaller toward the distal end side. For this reason, there is a problem that the distal end side bending amount becomes smaller than the proximal end side bending amount, and the distal end side inclination angle becomes smaller than the case where there is no frictional force.
In addition, there is a problem that a deviation occurs in which the amount of rotation for each bending piece becomes smaller toward the tip side.
Therefore, there is a problem that the bending performance of the bending tube is inferior compared with the case where each bending piece rotates evenly.

  The present invention has been made in view of the above problems, and an object thereof is to provide a bending mechanism that can improve the bending performance of a bending tube portion.

  In order to solve the above-mentioned problem, in the invention according to claim 1, the distal end portion, a curved tube portion having a plurality of link members coupled so as to be rotatable and having one end side connected to the distal end portion, One end is connected to the distal end portion, and an operation wire for bending the bending tube portion by advancing and retreating inside the bending tube portion, and inserted through the bending tube portion to resist bending of the bending tube portion Each of the plurality of link members includes a wire insertion hole through which the operation wire is inserted so as to be able to advance and retreat, and a cross section perpendicular to a central axis of the bending tube portion. A core member guide hole for positioning the member insertion position and slidably holding the core member in the axial direction, the core member being rigid from the one end side to the other end side of the bending tube portion Is configured to be increased.

  According to a second aspect of the present invention, in the bending mechanism according to the first aspect, the rigidity of the core member is increased stepwise.

  According to a third aspect of the present invention, in the bending mechanism according to the first aspect, the core member has a beam whose cross-sectional secondary moment is increased from the one end side to the other end side of the bending tube portion. It is set as the structure which consists of members.

  According to a fourth aspect of the present invention, in the bending mechanism according to the third aspect, the beam member is constituted by a hollow member.

  According to a fifth aspect of the present invention, in the bending mechanism according to the first aspect, the core member is a beam member whose bending elastic coefficient is increased from the one end side to the other end side of the bending tube portion. It is set as the structure which consists of.

  According to a sixth aspect of the present invention, in the bending mechanism according to the fifth aspect, the bending elastic modulus of the beam member is increased by changing a density of a material used for the beam member.

  According to a seventh aspect of the present invention, in the bending mechanism according to the fifth aspect, the beam member is made of a composite material in which a plurality of materials are combined, and the bending elastic modulus of the beam member is the plurality of materials. The composition ratio is increased by changing the composite ratio.

  According to an eighth aspect of the present invention, in the bending mechanism according to the first aspect, the core member is a coil pipe in which a wire having a uniform cross section is coiled, and the rigidity of the core member is as follows: It is set as the structure increased by changing the winding space | interval of the said wire.

  In a ninth aspect of the present invention, in the bending mechanism according to the first aspect, the core member comprises a coil pipe in which a wire having a uniform cross section is coiled, and the rigidity of the core member is The winding diameter of the wire is changed and increased.

  According to a tenth aspect of the present invention, in the bending mechanism according to any one of the first to ninth aspects, the core member is made of a superelastic material having superelasticity.

  According to an eleventh aspect of the present invention, in the bending mechanism according to any one of the first to ninth aspects, the core member is made of a resin material.

  The invention according to claim 12 is the bending mechanism according to any one of claims 1 to 9, wherein the core member is inserted through the center of the bending tube portion.

  In the invention according to claim 13, in the bending mechanism according to any one of claims 1 to 9, the core member is inserted into a position closer to the center of the bending tube portion in parallel with the operation wire. The configuration.

  The invention according to claim 14 is the bending mechanism according to any one of claims 1 to 9, wherein the core member includes a plurality of core members arranged at an equal angle around a central axis of the bending tube portion. To do.

  The invention according to claim 15 is the bending mechanism according to any one of claims 1 to 9, wherein the core member guide hole of the link member receives and holds the core member at a plurality of locations along the axial direction. It is set as the structure made to do.

  According to the bending mechanism of the present invention, since the rigidity of the core member is increased from the one end side connected to the distal end portion toward the other end side in the bending tube portion, it is relatively easy to bend on the distal end side, There is an effect that the bending performance of the bending tube portion can be improved.

It is a typical perspective view which shows an example of the bending mechanism which concerns on the 1st Embodiment of this invention. It is typical sectional drawing which shows the structure of the principal part of the bending mechanism which concerns on the 1st Embodiment of this invention, the side view of the A view, and BB sectional drawing. It is a typical perspective view which shows an example of the link member used for the bending mechanism which concerns on the 1st Embodiment of this invention. It is a typical perspective view which shows an example of the core member of the bending mechanism which concerns on the 1st Embodiment of this invention, and the example of the core member of a 1st modification. It is typical sectional drawing which shows the mode at the time of the bending of the bending pipe part of the bending mechanism which concerns on the 1st Embodiment of this invention. It is the typical perspective view of the core member used for the bending mechanism of the 2nd modification of the 1st Embodiment of this invention, and an exploded perspective view. It is typical sectional drawing containing the central axis of the core member used for the bending mechanism of the 3rd modification of the 1st Embodiment of this invention. It is typical sectional drawing which shows the structure of the principal part of the bending mechanism which concerns on the 2nd Embodiment of this invention. It is a typical perspective view which shows an example of the link member used for the bending mechanism which concerns on the 2nd Embodiment of this invention. It is typical sectional drawing which shows the structure of the principal part of the bending mechanism of the modification (4th modification) of the 2nd Embodiment of this invention. It is typical sectional drawing which shows the structure of the principal part of the bending mechanism which concerns on the 3rd Embodiment of this invention, the side view of the C view, and DD sectional drawing. It is a typical perspective view which shows an example of the link member used for the bending mechanism which concerns on the 3rd Embodiment of this invention. It is a typical front view which shows the modification (5th modification) of the core member which can be used for the bending mechanism of the 1st Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
The bending mechanism according to the first embodiment of the present invention will be described.
FIG. 1 is a schematic perspective view showing an example of a bending mechanism according to the first embodiment of the present invention. Fig.2 (a) is typical sectional drawing which shows the structure of the principal part of the bending mechanism which concerns on the 1st Embodiment of this invention. FIG.2 (b) is a side view of the A view in Fig.2 (a). FIG.2 (c) is BB sectional drawing of Fig.2 (a). FIG. 3 is a schematic perspective view showing an example of a link member used in the bending mechanism according to the first embodiment of the present invention. FIG. 4A is a schematic perspective view showing an example of the core member of the bending mechanism according to the first embodiment of the present invention.
Each figure is a schematic diagram, and the size and shape of each member are exaggerated for ease of viewing (the same applies to the following drawings).

The bending mechanism 1 according to the present embodiment changes the position and posture of the distal end portion by bending the distal end side of the elongated flexible tubular body in various directions by operation from the proximal end side (hereinafter referred to as bending). For example, it can be suitably used for devices such as an endoscope and a manipulator.
As shown in FIG. 1, the schematic configuration of the bending mechanism 1 includes an insertion portion 3 having an elongated tubular shape as a whole, and a drive unit that is connected to the proximal end side of the insertion portion 3 and moves the distal end of the insertion portion 3 in a curved manner. It consists of two.
The insertion portion 3 includes a distal end portion 6, a bending tube portion 5, and a flexible tube portion 4 from the distal end side toward the proximal end side.
In the following, unless there is a possibility of misunderstanding, when representing the shape and arrangement position of each member in the bending mechanism 1, the relative positional relationship in the extending direction of the insertion portion 3 is expressed as the tip of the insertion portion 3. Depending on the side and the base end side, they may be referred to as the front end side and the base end side.
FIG. 2A is a cross-sectional view including the central axis O of the insertion portion 3 when the bending of the insertion portion 3 is released and the whole is straightened (hereinafter referred to as a straight state). In the case of FIG. 2A, the left side in the figure is the distal end side, and the right side in the figure is the proximal side.
In the following, for simplicity, the shape and positional relationship of each member will be described in such a straight state unless otherwise specified.

The distal end portion 6 is a member that is bent and moved, and is formed into a suitable shape according to the purpose of the apparatus in which the bending mechanism 1 is used.
For example, when used in an endoscope, as shown in FIG. 2 (b), the distal end portion 6 is formed in a disk shape or a columnar shape, and the circumferential direction extends from the end surface 6b on the distal end side to the end surface 6a on the proximal end side. Four through holes (see FIG. 2A) are provided at equally-divided positions, and an imaging unit 40 that acquires an image in front of the tip 6 and a light that illuminates the front of the tip 6 are provided in each through-hole. The guide 41 and treatment instrument channels 42 and 43 for advancing and retreating an appropriate treatment instrument from the end surface 6b toward the front of the distal end portion 6 are attached.
Although not shown in FIG. 2A, the imaging unit 40 includes an imaging lens, a CCD (Charge Coupled Device), and a signal line connected to the CCD from the distal end side. In addition, it is arranged extending inside the flexible tube portion 4, and an end portion is connected to an electrical component provided inside the drive portion 2.
Similarly, although not shown in FIG. 2A, the light guide 41 and the treatment instrument channels 42 and 43 are also arranged so as to extend inside the bending tube portion 5 and the flexible tube portion 4.
Further, when the bending mechanism 1 is used as a manipulator, a treatment portion attachment portion, for example, an attachment hole portion, a mount, a screw portion, an engagement portion, for attaching a treatment portion such as forceps to the distal end portion 6 detachably. It has a shape such as.

The center of the distal end portion 6 is disposed so as to be coaxial with the central axis O of the insertion portion 3.
On the end surface 6 a of the distal end portion 6, one end portion of the operation wire 26 for operating the bending of the bending tube portion 5 is placed at a position that divides the circumference drawn by the radius r from the center of the distal end portion 6 into four equal parts. It is fixed. However, since FIG. 2A is a cross-sectional view including the central axis O, one provided on the front side of the sheet is not shown.

In the present embodiment, the four operation wires 26 shown in the figure are actually composed of two operation wires 26 bent in a U-shape at the center and extending in parallel with each other. The parallel wire portions are visible. The paired wire portions are arranged in a positional relationship facing each other in the radial direction across the central axis O of the insertion portion 3. That is, the operation wires 26A and 26B facing in the vertical direction shown in FIGS. 2 (a) and 2 (b) are constituted by parallel wire portions of one operation wire 26 bent in a U-shape. Yes. Further, the operation wires 26C and 26D (see FIG. 2B) facing in the direction perpendicular to the paper surface of FIG. 2A are wires forming a parallel pair in the other operation wire 26 bent in a U shape. It consists of parts.
In the straight state of the insertion portion 3 shown in FIG. 2A, the operation wires 26 provided in this way are straightened while keeping parallel to each other inside the bending tube portion 5 and the flexible tube portion 4. ing. Although not particularly illustrated, the U-shaped bent portions of the two pairs of operation wires 26 are wound around a drive pulley (not shown) in the drive unit 2.
In the following, the operation wires 26A, 26B, 26C, and 26D that are the two pairs of wire portions in the insertion portion 3 may be simply referred to as four operation wires 26 unless there is a possibility of misunderstanding.

  As long as the operation wire 26 is an elongate linear member, a suitable material and a structure can be employ | adopted. For example, as the material of the operation wire 26, metal, synthetic resin, or the like can be used. Further, as the configuration of the operation wire 26, a stranded wire or a single wire can be adopted.

In addition, a distal end attachment portion 10a that is an end portion on the distal end side of the core member 10 is embedded in the center of the end face 6a, and is attached by, for example, soldering or adhesion.
The core member 10 is provided so as to be inserted into the bending tube portion 5 and resists bending of the bending tube portion 5, and the rigidity thereof is from the distal end side to the proximal end side of the bending tube portion 5. Has been increased.
In this embodiment, it consists of a material with a uniform bending elastic modulus and density, and as shown to Fig.4 (a), a cross-sectional diameter is continuous toward the base end attachment part 10b of the base end side from the front end attachment part 10a. It is made of a beam member having a shape of a solid round bar with an increasing gradient. Thereby, the bending rigidity of the core member 10 is continuously increased from the distal end side toward the proximal end side.
The axial stiffness distribution of the core member 10 can be appropriately set according to the required bending characteristics of the bending tube portion 5. For this reason, the gradient of the core member 10 may be a tapered shape having a certain size or may be changed in the axial direction. For example, the intermediate portion may swell or narrow compared to a certain taper.

Although FIG. 4A is a schematic diagram, detailed illustration is omitted, but the tip mounting portion 10a and the base end mounting portion 10b are, for example, round with no gradient so as to facilitate mounting. You may process into a stick | rod or provide an uneven | corrugated | grooved part.
As shown in FIG. 2 (a), the base end mounting portion 10b of the core member 10 is embedded in a core member fixing portion 21c of the connecting portion 21 of the flexible tube portion 4 described later, for example, by soldering or bonding. It is fixed to the core member fixing part 21c.

As the material of the core member 10, an appropriate metal, synthetic resin, or the like can be adopted as long as the material has a uniform bending elastic modulus and density.
The core member 10 of this embodiment employs a super elastic material.
Here, the superelastic material refers to a material exhibiting a superelastic effect. The superelastic effect means that even if a large deformation strain (for example, about 8%) exceeding the Hooke's law is given, the strain disappears immediately when the stress is removed and the original shape is restored. In a metal material that does not have a superelastic effect, when a large deformation strain (for example, about 0.5%) exceeding the elastic region is applied, only the elastic deformation returns and permanent set remains even if stress is removed.
In a superelastic material, when a force is applied in the state of a matrix, martensite is generated from the matrix, and the crystal changes its direction one after another to cause a macroscopic deformation of the outer shape. When the force applied to the superelastic material is removed, the superelastic material returns to the parent phase while maintaining the connection between the crystals, so that the macroscopic shape also returns to the original shape.
Examples of alloys having a superelastic effect include titanium-nickel (Ti-Ni) alloys, copper-aluminum-nickel (Cu-Al-Ni) alloys, nickel-aluminum (Ni-Al) alloys, and the like. it can. Moreover, the iron-aluminum (Fe-Al) alloy which expresses huge superelasticity without producing a martensitic transformation can also be mentioned.

The bending tube portion 5 is bent by the driving portion 2 in order to move the distal end portion 6 in a bending manner, and a plurality of link members 24 are connected in the axial direction, and the outer peripheral surface thereof is a flexible tube (not shown). Is configured to be covered.
The centers of the link members 24 are arranged so as to be coaxial with the central axis O of the insertion portion 3 in a state in which the bending tube portion 5 is extended straight.
Each link member 24 has a substantially common shape. For this reason, especially when it is necessary to explain the difference in shape and arrangement, as shown in FIG. 2 (a), the link members 24A, 24B, 24C, ..., 24N will be described as being connected.

As shown in FIGS. 2 (a) and 3, the link member 24 has an annular ring part 24d and a length substantially equal to the axial length of the ring part 24d along the central axis of the ring part 24d. From the bottomed cylindrical core member guide portion 24g provided on the four sides, four support columns 24e connecting the core member guide portion 24g to the inner peripheral surface of the annular portion 24d, and the end surface on the tip side of the annular portion 24d A pair of flat projection pieces 24a projecting toward the distal end side, and a pair of flat projection pieces 24b projecting proximally from the end face on the proximal end side of the annular portion 24d are provided.
As the material of the link member 24, for example, a molded product of metal or synthetic resin, or a composite thereof can be adopted.

The core member guide portion 24g has an outer diameter larger than that of the core member 10, and the core member 10 has a central axis of the annular portion 24d, that is, a curved tube, at the center of the bottom portion on the distal end side and the proximal end side, respectively. A distal-side guide hole 24h (core member guide hole) and a proximal-side guide that hold the core member 10 in the radial direction and slidably hold in the axial direction so as to be coaxial with the central axis of the portion 5 A hole 24i (core member guide hole) is provided therethrough.
The axial widths (hole depths) of the distal end side guide hole 24h and the proximal end side guide hole 24i are sufficiently narrower than the axial width of the annular portion 24d, and are 2 away from the core member 10 in the axial direction. It can be held in place.
In each link member 24, the inner peripheral surface of the core member guide portion 24g between the distal end side guide hole 24h and the proximal end side guide hole 24i is formed in the inserted core member 10 as shown in FIG. The clearance space 24j is formed on the outer peripheral side of the core member 10 and is separated from the outer peripheral surface.
For this reason, the neutral member 10 is rotatably supported by the core member 10 at the distal end side guide hole 24h and the proximal end side guide hole 24i that are spaced apart in the axial direction. When the core member 10 is curved, the core member 10 can be bent and deformed in the radial direction within the range of the size of the escape space 24j.

The inner diameters of the distal-side guide hole 24h and the proximal-side guide hole 24i are preferably set to be an inner diameter that forms a slight gap with respect to the outer diameter of the inserted core member 10. For this reason, it is preferable to change each internal diameter according to the position where the link member 24 is arrange | positioned. Furthermore, in each link member 24, it is preferable that the proximal end guide hole 24i is provided with a larger diameter than the distal end side guide hole 24h.
However, if the variation in the position of the straight tip portion 6 is within an allowable range depending on the outer diameter of the core member 10 and the gradient, or if the bending characteristics of the bending tube portion 5 are not significantly affected, the bending tube The inner diameters of some or all of the distal-side guide holes 24h and the proximal-side guide holes 24i of the link member 24 constituting the portion 5 may be made common.

  The strut portion 24e is provided in a cross shape with the core member guide portion 24g as the center in accordance with the insertion position of the operation wires 26A, 26B, 26C, and 26D in the straight state. Each strut portion 24e has an inner diameter through which the operation wire 26 is slidably inserted, and a wire insertion hole 24f through which the operation wires 26A, 26B, 26C, 26D are inserted one by one is penetrated in the axial direction. . These wire insertion holes 24f are provided at positions that divide the circumference drawn by the radius r from the center of the annular portion 24d into four equal parts.

The pair of protruding piece portions 24a and the pair of protruding piece portions 24b are opposed to each other in the radial direction across the center of the annular portion 24d, and are provided in a positional relationship in which the opposed directions are orthogonal to each other. In this embodiment, each opposing direction is made to correspond to the radial direction where each support | pillar part 24e was extended.
The projecting piece 24 a is projected at a position substantially aligned with the outer peripheral surface of the link member 24, and the projecting piece 24 b is projected from a position shifted inward by about the plate thickness of the link member 24 from the outer peripheral surface of the link member 24. Yes.
Each projecting piece 24a, 24b is provided with a through-hole 24c penetrating in the plate thickness direction.

In the link member 24 having such a configuration, between the pair of link members 24 that are adjacent to each other in the axial direction, the other link member 24 is located on the inner side in the opposing direction of each protruding piece portion 24a of the one link member 24. Each of the projecting piece portions 24b is inserted and disposed so that the through holes 24c overlap each other, and the through holes 24c are rotatably connected to each other through the connecting shaft 25.
Further, a pair of projecting pieces 24a and 1 having the same shape and positional relationship as described above are formed on the end surface 6a of the tip 6 and the end surface 21d on the tip of the connecting portion 21 of the flexible tube 4 described later. A pair of projecting piece portions 24b are provided. As a result, the most distal link member 24 and the most proximal link member 24 of the bending tube portion 5 are respectively connected to the proximal end surface of the distal end portion 6 and the distal end of the connection portion 21 of the flexible tube portion 4. In the same manner as described above, the end surfaces on the side are connected so as to be rotatable.
Each projecting piece 24a on the end surface 6a of the tip 6 is provided so as to face each other with a pair of operation wires 26 facing each other in the direction perpendicular to the drawing sheet with the center of the tip 6 interposed therebetween. Yes.

With such a configuration, the bending tube portion 5 can be bent in two axial directions by a plurality of linked members 24. For example, as shown in FIG. 2 (a), the link members 24A, 24B, and 24C sequentially connected from the front end side are capable of rotating with respect to each other about the vertical axis in the paper surface. 24B and 24C are connected to each other so as to be rotatable about a vertical axis on the paper surface.
Further, since the four operation wires 26 inserted into the inner peripheral side of the link member 24 are inserted into the wire insertion holes 24f provided at four positions in each link member 24, the bending tube portion 5 is bent. However, they are arranged along the axial direction at a substantially constant distance from the inner peripheral surface of the annular portion 24d of the link member 24.

Moreover, the support | pillar part 24e of the link member 24 is arrange | positioned in the positional relationship which divides the inside of the annular ring part 24d into 4 in the circumferential direction. For this reason, as shown in FIG. 3, a hole H having a quadrant cross section penetrating in the axial direction of the link member 24 is formed between the support column 24e and the inner peripheral surface of the ring portion 24d. Is formed.
Since each link member 24 has a hole H, a space having a quadrant cross section that communicates from the distal end side to the proximal end side of the bending tube portion 5 is formed, and the imaging attached to the distal end portion 6 is formed. The signal line of the unit 40, the light guide 41, and the treatment instrument channels 42 and 43 can be inserted in the axial direction.

The flexible tube unit 4 is connected to the bending tube unit 5 and the driving unit 2, and the operation wire 26 inserted into the bending tube unit 5, the signal line of the imaging unit 40, the light guide 41, and the treatment instrument channels 42 and 43. Is guided to the drive unit 2.
As shown in FIG. 2A, the schematic configuration of the flexible tube portion 4 is a hollow and flexible structure in which an end portion on the base end side is connected to the drive portion 2 and forms the outer peripheral surface of the flexible tube portion 4. And a connecting portion 21 connected to the end of the flexible tube 28 on the distal end side.

The connecting portion 21 is a disc member having substantially the same outer diameter as the bending tube portion 5 and the flexible tube 28.
A core member fixing portion 21c, which is a hole for fixing the proximal end mounting portion 10b of the core member 10, is provided at the center of the end surface 21d on the distal end side of the connecting portion 21. The core member fixing portion 21c of the present embodiment is provided with a through hole 21g penetrating to the end surface 21e at the center of the bottom surface.
Further, on the outer peripheral portion of the end face 21d, a projecting piece portion 24a connected to the projecting piece portion 24b of the most proximal end link member 24N of the bending tube portion 5 via a connecting shaft 25 is provided. Although not shown in FIG. 2A, a protrusion at the same position on the link member 24N is provided at a position (on the front side of the drawing) facing the protruding piece 24a in the drawing with the center of the connecting portion 21 in between. A protruding piece portion 24a connected in the same manner as the piece portion 24b is provided.
In addition, a tube fixing portion 21 f that is fitted into the end portion of the flexible tube 28 is provided on the outer peripheral portion on the proximal end side of the connection portion 21. The flexible tube 28 fitted on the tube fixing portion 21f is fixed to the connection portion 21 by, for example, adhesion.
Moreover, the connection part 21 is arrange | positioned coaxially with the central axis O of the insertion part 3 in the straight state shown to Fig.2 (a).

The end surface 21e is provided with four holes 21b for inserting and fixing the four metal pipes 22 in parallel to the central axis of the connection portion 21 from the end surface 21e to the intermediate portion in the axial direction. . The shape of each hole 21 b is a cylindrical hole having an inner diameter slightly larger than the outer diameter of the metal pipe 22. As shown in FIG. 2C, the centers of the holes 21b are arranged at positions that divide the circumference drawn by the radius r from the center of the connecting portion 21 into four equal parts.
These hole portions 21b are respectively arranged in the facing direction of the pair of projecting piece portions 24b provided on the end surface 21d and in the direction orthogonal to the facing direction.
Therefore, in the straight state shown in FIG. 2A, each wire insertion hole 24 f is opposed to each wire insertion hole 21 a of the connection portion 21.

  A wire insertion hole 21a, which is a through hole having a diameter smaller than that of the core member fixing portion 21c and larger than that of the operation wire 26, is provided in the center of the bottom surface of each hole 21b up to the end surface 21d along the axial direction. ing.

  Further, as shown in FIG. 2 (c), four through holes 21h are provided in an intermediate portion in the circumferential direction of the hole portion 21b and the wire insertion hole 21a so as to penetrate from the end surface 21d to the end surface 21e in the axial direction. It has been. The diameters of these through-holes 21h are sized so that the signal line of the imaging unit 40, the light guide 41, and the treatment instrument channels 42 and 43 inserted into the bending tube portion 5 can be respectively inserted. The portion 5 is inserted into the flexible tube portion 4.

The metal pipe 22 allows the operation wires 26 inserted into the wire insertion holes 21a of the connection portion 21 to be inserted into the flexible tube portion 4, and the insertion length in the flexible tube portion 4 is constant. It is for maintaining, and consists of a flexible hollow member. For this reason, although not particularly illustrated, the other end of the metal pipe 22 is a hole similar to the connection portion 21 at the end on the proximal end side of the flexible tube portion 4 or a fixed position inside the drive portion 2. It is being fixed by the receiving member provided with 21b.
The outer diameter of the end of the metal pipe 22 is smaller than the inner diameter of the hole 21 b, and the inner diameter of the inner peripheral surface 22 a of the metal pipe 22 is larger than the outer diameter of the operation wire 26.
The pipe thickness (dimension obtained by subtracting the inner radius from the outer radius of the tube hole) and the material of the metal pipe 22 are broken by the external force received by the metal pipe 22 disposed in the flexible pipe portion 4. It has a strength that does not cause crushing, and has flexibility such that the flexible tube portion 4 can be bent within a necessary range.
As a material of the metal pipe 22, for example, stainless steel, titanium, brass, or copper alloy can be suitably used.

Next, operation | movement of the bending mechanism 1 of this embodiment is demonstrated focusing on an effect | action of the core member 10. FIG.
FIG. 5 is a schematic cross-sectional view showing a state when the bending tube portion of the bending mechanism according to the first embodiment of the present invention is bent.

In the bending mechanism 1, each operation wire 26 is driven by the drive unit 2 to change the amount of the wire portion of the operation wire 26 that is inserted into the insertion unit 3, thereby changing the bending amount of the bending tube unit 5. Can do.
For example, in FIG. 2A, when the operation wire 26A is pulled and pulled to the proximal end side and the operation wire 26B is drawn out to the distal end side, the length of the operation wire 26B is longer than the length of the operation wire 26A in the insertion portion 3. Therefore, the insertion portion 3 receives a driving force for bending the distal end portion 6 upward in the drawing from the operation wires 26A and 26B.
At this time, since the operation wires 26A and 26B are inserted into the metal pipe 22 whose length hardly changes in the axial direction inside the flexible tube portion 4, a difference in length between the operation wires 26A and 26B appears. Is the inside of the bending tube portion 5. For this reason, in the inside of the bending tube part 5, each link member 24 which can be rotated around a vertical axis | shaft of a paper surface is rotated according to the change of the length of operation wire 26A, 26B. Thereby, the bending tube portion 5 is bent, and the distal end portion 6 provided at the distal end thereof is bent and moved.

FIG. 5 shows this operation as an operation between the adjacent link members 24B and 24C.
Between the link members 24B and 24C, the lengths of the operation wires 26A and 26B stretched between the link members 24B and 24C are changed. As a result, the link member 24B and the link member 24C are connected to the connecting shaft 25 connected to each other. As a center, it is rotated by a rotation angle θ clockwise in the figure.
At this time, the core member 10 between the link members 24B and 24C receives an external force from the position of the base end side guide hole 24i of the link member 24B and the front end side guide hole 24h of the link member 24C, and receives the base end side guide hole 24i. And it is bent between the front end side guide holes 24h.
The rotation angle θ is determined by the angle at which the moment of force acting on the link members 24B and 24C from the operation wires 26A and 26B and the moment of reaction force acting on the core member 10 are balanced.

  Similarly, if the operation wires 26 </ b> C and 26 </ b> D are driven by the drive unit 2, the distal end portion 6 can be bent and moved in a direction orthogonal to the operation wire 26 </ b> C and 26 </ b> D. As described above, in the bending mechanism 1, the distal end portion 6 can be bent and moved in the biaxial directions orthogonal to each other by changing the drive amount of each operation wire 26.

Further, by returning the pulling amount and the feeding amount of each operation wire 26, the bending tube portion 5 can be returned to a straight state. At that time, since the core member 10 applies an elastic restoring force to each link member 24 until it reaches the straight state, it is easy to return to the straight state.
Further, since the core member 10 of the present embodiment is made of a superelastic material, the range of deformation strain that can be restored to the original shape is large, so the amount of bending is increased compared to the case of using a metal material that easily yields. However, it can be restored to straightness with good reproducibility.

In such a bending movement operation, a moving load is generated at the distal end portion 6 and the bending tube portion 5, so that a tension is generated at the operation wire 26 that is drawn to the proximal end side. This tension acts as an external force on the link member 24 through the wire insertion hole 24f through which the operation wire 26 is inserted, and the operation wire 26 receives a frictional force from the wire insertion hole 24f.
Due to the influence of this frictional force, the operation wire 26 is less likely to move toward the distal end side, and the amount of rotation of the link member 24 tends to be larger at the proximal end side and smaller at the distal end side.

This inventor pays attention to this point, and can suppress or cancel the variation in the axial direction of the rotation angle between the link members 24 by suppressing the rotation amount between the adjacent link members 24 toward the proximal end side. I came up with it.
In the present embodiment, by continuously increasing the rigidity of the core member 10 from the distal end side toward the proximal end side, the proximal end guide hole 24i and the distal end side guide hole 24h between the link members 24 adjacent to each other. The rigidity of the portion of the core member 10 inserted therebetween increases monotonously from the distal end side toward the proximal end side. For this reason, the resistance of the rotation received from the core member 10 increases as the link member 24 is adjacent on the base end side, and as a result, the variation in the rotation angle between the link members 24 can be reduced.
Further, by appropriately setting the amount of change in the rigidity of the core member 10, the variation in the rotation angle can be offset. That is, the bending tube portion 5 can be bent in an arc shape.
Further, the rotation angle on the distal end side can be made larger than that on the proximal end side.

Thus, in the bending mechanism 1, the bending performance on the distal end side can be relatively improved as compared with the conventional bending mechanism provided with the core member having a uniform cross section. Therefore, the inclination angle of the distal end portion 6 can be changed without increasing the amount of movement of the distal end portion 6 due to the proximal end side being bent more greatly than the distal end side.
For this reason, for example, when employed in an endoscope, a manipulator, etc., the direction in which the distal end portion 6 faces can be easily changed in a narrower space, and the operability can be improved.

  Thus, according to the bending mechanism 1 of the present embodiment, the rigidity of the core member 10 is increased from one end side connected to the distal end portion 6 in the bending tube portion 5 toward the other end side. The bending characteristic that the distal end side of the bending tube portion 5 is not easily bent by the frictional force between the link member 26 and the link member 24 can be corrected. Accordingly, the bending performance of the bending tube portion 5 can be improved because it is relatively easy to bend on the distal end side.

  Moreover, in this embodiment, the core member 10 is arrange | positioned on the center of the bending tube part 5, ie, the neutral axis | shaft of a curve. For this reason, compared with the case where the core member 10 is decentered from the center of the bending tube portion 5, the outer surface of the core member 10, the proximal-side guide hole 24i, and the distal-side guide hole 24h at the time of bending are arranged. The amount of sliding between them can be reduced. For this reason, the durability of the core member 10 can be improved.

(First modification)
Next, a first modification of the bending mechanism 1 of the first embodiment will be described.
FIG. 4B is a schematic perspective view showing an example of the core member of the first modified example of the first embodiment of the present invention.

In this modification, a core member 10A shown in FIG. 4B is provided instead of the core member 10 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.
The core member 10A of the present modification is provided with a hollow portion 10c penetrating in the axial direction at the center of the core member 10 of the first embodiment.
The shape and size of the hollow portion 10c can be set to an appropriate shape and size depending on how the axial rigidity of the core member 10A is changed.
For example, in the example shown in FIG. 4B, the hollow portion 10c is coaxial with the outer peripheral surface 10d of the core member 10A, and, like the outer peripheral surface 10d, is directed from the distal end mounting portion 10a side to the proximal end mounting portion 10b side. Thus, the inner diameter gradually increases continuously. For this reason, the cross section of the core member 10A is annular. The thickness of the ring (the difference between the outer radius and the inner radius) may be constant in the axial direction or may vary monotonously in the axial direction.
The core member 10A of the present modification is an example when the rigidity along the axial direction is changed by changing the secondary moment of section in the axial direction, as in the first embodiment.

According to this modification, the bending performance of the bending tube portion 5 can be improved in the same manner as in the first embodiment.
Moreover, according to this modification, rigidity can be changed by changing the cross-sectional shape and cross-sectional dimension of the hollow part 10c. Accordingly, even when the outer peripheral surface 10d has the same shape as the outer peripheral surface of the core member 10, for example, by increasing the cross-sectional area on the inner peripheral side of the hollow portion 10c on the proximal end side, the proximal end side compared to the core member 10 The rigidity of can be reduced.
For this reason, even if it uses the link member 24 of the said 1st Embodiment as it is, it becomes possible to change the bending characteristic of the bending tube part 5. FIG.
Moreover, even if the shape of the outer peripheral surface 10d is a shape having a constant taper, the rate of change in rigidity along the axial direction can be freely changed.
In addition, by setting the cross-sectional shape of the hollow portion 10c to, for example, a square hole or a cross hole, anisotropy can be imparted to the cross-sectional secondary moment. Thereby, the bending movement range of the bending mechanism 1 can be made anisotropic.

Further, in this modification, the hollow portion 10c of the core member 10A penetrates in the axial direction, so that the hollow portion 10c is formed by providing a through hole in front of the tip attachment portion 10a attached to the tip portion 6. A through hole that communicates from the tip of the tip 6 to the through hole 21g of the connecting portion 21 can be used. For this reason, for example, it can be used as a space through which a linear member such as an optical fiber or a tubular member such as a water absorption pipe is inserted. Moreover, it is also possible to use the hollow part 10c itself as a pipe part.
For this reason, the space in the bending pipe part 5 can be used effectively.

(Second modification)
Next, a second modification of the bending mechanism 1 of the first embodiment will be described.
6A and 6B are a schematic perspective view and an exploded perspective view of a core member used in the bending mechanism of the second modified example of the first embodiment of the present invention, respectively.

  In this modification, instead of the core member 10 of the first embodiment, a core member 11 shown in FIG. 6A is provided, and in accordance with the outer shape of the core member 11, the front end side guide hole of the link member 24 is provided. 24h, the inner diameter of the proximal end side guide hole 24i is changed. Hereinafter, a description will be given centering on differences from the first embodiment.

As shown in FIG. 6 (a), the core member 11 of the present modification includes, in order from the distal end side, an elongated columnar bar 11A, and a cylindrical pipe member 11B having an outer diameter larger than that of the bar 11A, A cylindrical pipe member 11C having an outer diameter larger than that of the pipe member 11B is a rod-like beam member having a shaft diameter that changes in multiple stages as a whole.
Therefore, the inner diameters of the distal end side guide hole 24h and the proximal end side guide hole 24i of each link member 24 are set corresponding to the outer diameter of the core member 11 at the corresponding position. Therefore, the inner diameters of the distal end side guide hole 24h and the proximal end side guide hole 24i of each link member 24 are set to the same diameter, and the core member 11 corresponds to the outer diameters of the bar 11A and the pipe members 11B, 11C. Three types of inner diameters slightly larger than those can be adopted so that they can slide.
In this modification, an example of a rod-shaped member whose shaft diameter changes in three stages will be described as an example, but may be changed in four stages or more.

The cross-sectional shape of the core member 11 is set to a shape in which each bending rigidity (= bending elastic modulus × secondary moment of cross section) increases from the distal end mounting portion 10a toward the proximal end mounting portion 10b. Thus, the rigidity of the core member 11 of the present modification is increased in three stages from the distal end side to the other end side of the bending tube portion 5 in stages.
As described above, if the rigidity can be set, the material of the bar 11A and the pipes 11B and 11C is not particularly limited, and is not limited to the same material. As these materials, the same materials as the core member 10 can be adopted.

  Although the core member 11 in the bending mechanism 1 is not particularly illustrated, the tip of the bar 11A is attached to the tip portion 6 in the same manner as the core member 10 in the same manner as the core member 10, and is a pipe material. An end portion of the pipe material 11C opposite to 11B is attached to the connection portion 21 as a base end attachment portion 10b.

  For example, as shown in FIG. 6B, such a core member 11 has a size in which the inner diameter of one end of the pipe material 11B is fitted to the end of the bar 11A, and the other end of the pipe material 11B. It can be manufactured by connecting the outer diameter of the end portion to the end portion of the pipe member 11C by press fitting, bonding, soldering, or the like. At that time, the axial length of the connecting portion is made shorter than the distance of the central portion between the link members 24 adjacent to each other. As a result, even if the rigidity of the connecting portion changes peculiarly during processing, the connecting portion is not positioned between the link members 24 adjacent to each other, so that the bending characteristics of the bending tube portion 5 are affected. It can be prevented from reaching.

According to the core member 11 of the present modified example, the rigidity is increased in multiple stages. Therefore, the bending tube as a whole can be reduced by suppressing the variation in the rotation angle of each link member 24 of the bending tube portion 5 in multiple stages. The bending characteristics of the part 5 can be improved.
For example, if the rigidity is changed in multiple steps of the same number as the number of the link members 24, the same effect as that in which the change in rigidity along the axial direction is continuously changed like the core member 10 is exhibited. be able to.
According to the core member 11 of this modification, since it can be configured by connecting rods and pipes, the manufacture becomes easier as compared to the case of tapering along the axial direction.

  Note that the core member 11 of this modification example is configured with the rod 11A on the tip side, and the tip side may also be configured with a pipe material. Moreover, you may comprise the whole with a rod.

(Third Modification)
Next, a third modification of the bending mechanism 1 of the first embodiment will be described.
FIG. 7 is a schematic cross-sectional view including the central axis of the core member used in the bending mechanism of the third modified example of the first embodiment of the present invention.

This modification includes a core member 12 shown in FIG. 7 instead of the core member 11 of the second modification. Hereinafter, a description will be given centering on differences from the second modification.
The core member 12 is formed by forming the core member 11 as an integral bar, and is a cylindrical part having the same outer diameter and length as those of the bar 11A and the pipes 11B and 11C of the second modified example. The beam member includes 12a, 12b, and 12c, and a hollow hole portion 12d is provided through the center thereof. The end on the cylindrical portion 12a side constitutes the distal end attaching portion 10a, and the end on the cylindrical portion 12c side constitutes the proximal end attaching portion 10b.
The change in rigidity along the axial direction of the core member 12 is set to be the same as the change in rigidity of the core member 11 by appropriately setting the cross-sectional shape of the hollow hole portion 12d. For this reason, the shape of the hollow hole portion 12d is not limited to a cylindrical hole shape, and may be a conical hole shape, a multistage cylindrical hole shape, a polygonal hole shape, or the like.
The material of the core member 12 can be the same material as the core member 10. As a manufacturing method of the core member 12, molding, cutting, or the like can be employed.

  According to the core member 12 of the present modification, the number of parts is smaller than that of the core member 11 and the connecting portion is not provided, so that the manufacture becomes easy. Moreover, since there is no connection part, the dispersion | variation in the intensity | strength and durability resulting from the processing error in a connection part can be prevented.

[Second Embodiment]
Next, a bending mechanism according to the second embodiment of the present invention will be described.
FIG. 8 is a schematic cross-sectional view showing the configuration of the main part of the bending mechanism according to the second embodiment of the present invention. FIG. 9 is a schematic perspective view showing an example of a link member used in the bending mechanism according to the second embodiment of the present invention. FIG. 10 is a schematic cross-sectional view showing the configuration of the main part of the bending mechanism of the modification (fourth modification) of the second embodiment of the present invention.

As shown in FIG. 1, the bending mechanism 1A of the present embodiment includes an insertion portion 3A instead of the insertion portion 3 of the bending mechanism 1 of the first embodiment.
As shown in FIG. 8, the insertion portion 3 </ b> A includes a coil pipe 13 (core member) instead of the core member 10 of the insertion portion 3, and according to this change, the distal end portion 6 of the first embodiment, The link member 24 and the connection part 21 are changed to the tip part 6A, the link member 34, and the connection part 21A, respectively. Therefore, the bending mechanism 1A includes a bending tube portion 5A and a flexible tube portion 4A, respectively, instead of the bending tube portion 5 and the flexible tube portion 4 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.

As shown in FIG. 8 and FIG. 2A, the tip portion 6A has the core member 10 attached to the tip portion 6 of the first embodiment removed, and both end portions are embedded in the center of the end face 6a. The only difference is that a locking portion 36 formed in a bowl shape such as a U-shape or an L-shape is provided.
As shown in FIG. 8, the connecting portion 21A is obtained by deleting only the core member fixing portion 21c and the through hole 21g from the connecting portion 21 of the first embodiment.

As shown in FIG. 8, the coil pipe 13 is formed by winding a wire having a uniform cross section and a uniform bending elastic modulus to a constant coil diameter, and changing the winding interval from one end side in the axial direction. The member is gradually reduced toward the end side. The end portion of the coil pipe 13 is provided with a tip hook 13a at the end portion on the side where the winding interval is large, and a rear end hook 13b is provided at the end portion on the side where the winding interval is small.
For this reason, the bending deformation rigidity when the coil pipe 13 is regarded as a beam member is gradually increased from the front end hook 13a side toward the rear end hook 13b side.

Similarly to the link member 24 of the first embodiment, N link members 34 are connected to form the curved tube portion 5A. The link member 24 includes a distal end side guide hole 24h and a proximal end side guide hole 24i. Instead, a guide hole 34h having an inner diameter slightly larger than the outer diameter of the coil pipe 13 is provided.
For this reason, all the N link members 34 have a common shape. And it connects so that rotation is possible similarly to the link member 24, and the guide hole part 34h is connected to the axial direction in the straight state. Similarly to the link members 24A and 24N, the link members 34 at both ends are rotatably connected to the tip portion 6A and the connection portion 21A, respectively.
Inside the bending tube portion 5A, four operation wires 26 are inserted into the wire insertion holes 24f.

The coil pipe 13 is inserted into the guide hole 34h of each link member 34 with the front end hook 13a facing the front end 6A.
In FIG. 8, the winding interval is exaggerated for ease of viewing, but the winding interval of the coil pipe 13 is set to be narrower than the axial width of the guide hole 34 h at any position. . For this reason, the coil pipe 13 is slidably inserted into the guide hole 34h.

As shown in FIGS. 8 and 9, the rear end hook 13b of the coil pipe 13 is a rod-shaped locking member 35 disposed outside the guide hole 34h on the base end side of the link member 34 facing the connecting portion 21A. Is hooked and locked.
The locking member 35 is bonded to, for example, an end surface of the core member guide portion 24g of the link member 34, or is engaged with a groove portion or the like provided on an end surface on the proximal end side of the core member guide portion 24g. Thus, the position of the link member 34 in the direction along the central axis O is fixed.
The tip hook 13a of the coil pipe 13 is hooked and locked to the locking portion 36 of the tip 6A.
The distance in the straight state between the locking portion 36 and the locking member 35 is longer than the natural length of the coil pipe 13. For this reason, the coil pipe 13 is stretched between the locking portion 36 and the locking member 35, and the connected tip portion 6 </ b> A and the N link members 34 are connected to the coil pipe 13 in the axial direction. It receives compression force.
For this reason, since there is no backlash in the axial direction at each connecting portion of the link member 34, it is possible to realize a bending operation with higher reproducibility.

According to the bending mechanism 1A having such a configuration, when the operation wire 26 is driven by the drive unit 2 as in the first embodiment, the bending tube unit 5 is bent. At this time, since the coil pipe 13 whose rigidity increases from the distal end side toward the proximal end side instead of the core member 10 is provided, the proximal end side is more resistant to bending than the distal end side, and the proximal end is increased. The amount of bending of the side link member 34 is suppressed. Therefore, it is possible to correct the bending characteristic that the distal end side of the bending tube portion 5A is not easily bent by the frictional force between the operation wire 26 and the link member 34. Accordingly, the bending performance of the bending tube portion 5A can be improved because it is relatively easy to bend even on the distal end side.
Moreover, according to the bending mechanism 1A, since the shape of each link member 34 of the bending tube part 5 can be made common, the manufacturing cost of the bending tube part 5 can be reduced.
Further, according to the bending mechanism 1A, since the coil pipe 13 is used as the core member, for example, even when a wire material having no superelasticity such as a stainless steel wire material having a low material cost is used, a large amount of bending can be easily handled. be able to.

(Fourth modification)
Next, a bending mechanism 1B according to a modified example (fourth modified example) of the present embodiment will be described.
FIG. 10 is a schematic cross-sectional view showing the configuration of the main part of the bending mechanism of the modification (fourth modification) of the second embodiment of the present invention.

  As shown in FIG. 10, the bending mechanism 1B of the present modified example replaces the coil pipe 13, the distal end portion 6A, and the connecting portion 21A of the bending mechanism 1A of the second embodiment, respectively, with a core member 16 and a distal end portion, respectively. 6. A connection unit 21 is provided. By these changes, the bending mechanism 1B includes an insertion portion 3B and a bending tube portion 5B instead of the insertion portion 3A and the bending tube portion 5A of the second embodiment. Hereinafter, a description will be given focusing on differences from the second embodiment.

  The core member 16 in the insertion portion 3B is a rod-shaped member having the same outer diameter as that of the coil pipe 13, and has increased rigidity from one side in the axial direction toward the other side. And the front-end | tip attachment part 10a which is an edge part by the side with small rigidity is attached to the front-end | tip part 6 similarly to the front-end | tip attachment part 10a of the core member 10 of the said 1st Embodiment. Further, the end portion of the core member 16 on the side where the rigidity is high is attached to the connection portion 21 as in the case of the base end attachment portion 10b of the core member 10 of the first embodiment, although not particularly illustrated. However, the inner diameter of the core member fixing portion 21 c of the connection portion 21 is changed in accordance with the outer diameter of the core member 16.

The means for changing the rigidity of the core member 16 along the axial direction is not particularly limited.
For example, as a material of the core member 16, a composite material in which substances having different densities are combined is adopted, and a means for changing the flexural modulus by changing the composite ratio of these substances along the axial direction is given. Can do. The substance to be combined may be a compatible substance, or may be an incompatible substance such as a composite of synthetic resin and reinforcing fiber.
Further, for example, a configuration in which the outer periphery of a tape-shaped core material like the core member 10 of the first embodiment is covered with another material having a different bending elastic coefficient so as to have a cylindrical rod shape as a whole.
Further, in the core member 10A of the first modified example of the first embodiment, the outer peripheral surface 10d may be provided with a uniform outer diameter, and the hollow portion 10c may be formed in a tapered shape.
Further, for example, the bending stiffness may be changed stepwise in the axial direction by externally fitting a plurality of pipe materials having the same cross-sectional shape and different bending elastic moduli on the outer peripheral side of the core material having a uniform diameter. .

  According to such a bending mechanism 1B, the bending characteristic of the bending tube portion 5B can be improved and the shape of each link member 34 can be made common as in the second embodiment.

[Third Embodiment]
Next, a bending mechanism according to a third embodiment of the present invention will be described.
Fig.11 (a) is typical sectional drawing which shows the structure of the principal part of the bending mechanism which concerns on the 3rd Embodiment of this invention. FIG.11 (b) is a side view of the C view in Fig.11 (a). FIG.11 (c) is DD sectional drawing in Fig.11 (a). FIG. 12 is a schematic perspective view showing an example of a link member used in the bending mechanism according to the third embodiment of the present invention.

As shown in FIG. 1, the bending mechanism 1 </ b> C of the present embodiment includes an insertion portion 3 </ b> C instead of the insertion portion 3 of the bending mechanism 1 of the first embodiment.
As shown in FIG. 11A, the insertion portion 3 </ b> C includes four core members 14 instead of the core member 10 of the insertion portion 3, and according to this change, the distal end portion of the first embodiment. 6, the link member 24, and the connection part 21 are changed into the front-end | tip part 6B, the link member 37, and the connection part 21B, respectively. For this reason, the bending mechanism 1C includes a bending tube portion 5C and a flexible tube portion 4B, respectively, instead of the bending tube portion 5 and the flexible tube portion 4 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.

As shown in FIGS. 11A and 11B, the tip 6B has the core member 10 attached to the tip 6 of the first embodiment removed, and a hole 6d at the center of the end face 6a. It is different that it is provided. Another difference is that the tip attachment portions 14a of the four core members 14 are attached.
In addition, a tube member 44 that can be used, for example, to insert a treatment instrument or as a suction tube is attached to the hole 6d. Although the tube member 44 is not shown in FIG. 11A for ease of viewing, the tube member 44 is inserted into the bending tube portion 5C and the flexible tube portion 4B.

The core member 14 is provided to be inserted into the bending tube portion 5C and resists bending of the bending tube portion 5C, and the rigidity thereof is from the distal end side to the proximal end side of the bending tube portion 5C. Has been increased.
Similarly to the core member 10 of the first embodiment, the core member 14 of the present embodiment has a gradient in which the cross-sectional diameter gradually increases from the distal end mounting portion 14a toward the proximal end side. It consists of a solid round bar-shaped beam member. Thereby, the bending rigidity of each core member 14 is continuously increased from the distal end side toward the proximal end side.
However, unlike the core member 10, the proximal end of the core member 14 extends to the inside of the flexible tube portion 4 (not shown) and is fixed in the flexible tube portion 4B. For example, the proximal end side end portion of the core member 14 is embedded and attached to the distal end side of the disk member fitted into the flexible tube 28. This disk member is provided with a through-hole through which various members inserted into the metal pipe 22 and the flexible tube portion 4B are inserted.
For this reason, the total length of each core member 14 is longer than the total length of the bending tube portion 5C.

Further, the rigidity of the core member 14 is set so that the rigidity corresponding to the core member 10 is obtained by combining the four core members 14. Similar to the core member 10, the rigidity distribution of each core member 14 can be set as appropriate in accordance with the required bending characteristics of the bending tube portion 5B.
The material of the core member 14 is preferably a superelastic material.

As shown in FIG. 11B, the tip attachment portion 14a of each core member 14 has a radius r ₁ (r ₁ <r) that is inside the circumference of the radius r of the four operation wires 26 attached to the end surface 6a. On the concentric circle of r), it is embedded and fixed in the same manner as the operation wire 26 at a position aligned with each link member 37 in the radial direction.

As shown in FIGS. 11A and 12, the link member 37 has four guides in the same position instead of the four support portions 24e by deleting the core member guide portion 24g of the first embodiment. A portion 37e is provided.
Guide portions 37e from the center of the annular portion 24d to the extent beyond the circumference of radius r ₁ in the radially inward extended from the inner circumferential surface of the annular portion 24d inwardly, axially annular portion 24d It is a block-shaped projection part extended to the same width.
Each guide portion 37e is provided with a wire insertion hole 24f penetrating at the same position as in the column portion 24e. Further, on the circumference from the center of the radius r ₁ of the annular portion 24d, for insertion of the core member 14 in parallel with the wire insertion hole 24f, and the core member guide hole 37f which is penetrated in the axial direction is provided Yes.
The core member guide hole 37f of the present embodiment is a hole with a gradient that expands from the distal end side to the proximal end side in accordance with the outer diameter of the core member 14 so that the core member 14 can be slidably inserted. Consists of. For this reason, the core member guide hole 37 f of each link member 37 is provided in different sizes and shapes according to the position from the distal end side of the link member 37.

With such a configuration, the region sandwiched between the guide portions 37e in the link member 37 and the region sandwiched between the radial ends of the guide portions 37e in the central portion of the link member 37 are as a whole. A cross-shaped hole S having a cross-shaped cross section and penetrating in the axial direction is formed.
Further, since each link member 37 has a cross-shaped hole portion S, a cross-shaped cross-sectional space communicating from the distal end side to the proximal end side of the bending tube portion 5C is formed, and the imaging attached to the distal end portion 6B. The signal line of the unit 40, the light guide 41, the treatment instrument channels 42 and 43, and the tube member 44 can be inserted in the axial direction.

As shown in FIG. 11 (a), the connection portion 21B has an outer shape having an end surface 21e provided with a tube fixing portion 21f on the proximal end side and an outer periphery on the distal end side, like the connection portion 21 of the first embodiment. It is made into the disk shape which has the end surface 21d which has the two protrusion piece parts 24a in a part.
As with the link member 37, the internal shape of the connection portion 21B is provided with four guide portions 37e. For this reason, a cross-shaped hole S similar to the link member 37 is formed in the connection portion 21B.
However, unlike the link member 37, the guide portion 37e of the connection portion 21B is provided with a wire insertion hole 21a and a hole portion 21b instead of the wire insertion holes 24f.
These wire insertion holes 21a and hole portions 21b are provided at the same positions and shapes as the connection portions 21 of the first embodiment.

According to the bending mechanism 1C having such a configuration, when the operation wire 26 is driven by the drive unit 2 as in the first embodiment, the bending tube portion 5C is bent. At that time, since the four core members 14 whose rigidity increases from the distal end side toward the proximal end side instead of the core member 10 are provided, the proximal end side has a greater resistance to bending than the distal end side. The bending amount of the link member 37 on the base end side is suppressed. Therefore, it is possible to correct the bending characteristic that the distal end side of the bending tube portion 5B is not easily bent by the frictional force between the operation wire 26 and the link member 37. Accordingly, the bending performance of the bending tube portion 5C can be improved because it is relatively easy to bend on the distal end side.
In addition, according to the bending mechanism 1 </ b> C, the bending characteristics can be corrected by the four core members 14, so that the outer diameter of each core member 14 can be made thinner than that of the core member 10.
Further, according to the bending mechanism 1C, since the cross-shaped hole S is formed inside the bending tube portion 5C, a tubular or linear member such as the tube member 44 is inserted through the central portion of the bending tube portion 5. Therefore, the space inside the bending tube portion 5C can be used effectively.

Further, according to the bending mechanism 1C, the four core members 14 are arranged in parallel with the four operation wires 26, respectively, so that the radial position where the core member guide hole 37f is provided can be appropriately set. The bending performance can be changed. For example, the resistance at the time of bending can be increased by bringing the radius r ₁ of the circumference where the core member guide hole 37 f is arranged closer to the radius r.
In the present embodiment, each core member 14 has been described as an example of the same member, but the rigidity of each core member 14 may be changed. In this case, the magnitude of the resistance may be changed depending on the bending direction. Can be changed. For this reason, it becomes easy to have different bending characteristics depending on the bending direction. Further, even if the radial positions through which the core members 14 are inserted are different, the same effect is obtained.

In the bending mechanism 1C, each core member 14 is eccentric with respect to the bending center of the bending tube portion 5C. Therefore, if the bending amount is the same, the core member 14 is disposed at the center of the bending tube portion 5C. As compared with the case where the core member 14 is present, the expansion and contraction of the core member 14 becomes larger, and the sliding with the link member 37 also increases.
In the present embodiment, since the core member guide hole 37f has a cylindrical shape extending along the outer diameter of the core member 14, the core member 14 contacts the inner peripheral surface of the core member guide hole 37f as a whole. ing. For this reason, the sliding frictional force acting on the core member 14 is distributed over the entire contact surface of the core member 14, and the wear resistance is improved as compared with the case where the sliding is repeated in contact with dots. Can do.

  In the above description, when the core member is rod-shaped or tubular, the outer shape of the cross section perpendicular to the central axis is circular, but the cross-sectional shape of the outer shape of the core member is circular. It is not limited. For example, it may be rectangular or polygonal. In that case, it is preferable that the shape of the hole through which the core member is inserted matches the outer shape of the core member.

  In the description of the first and second embodiments, the core member inserted through the center of each link member is received at two locations on the front end side and the rear end side of the core member guide portion 24g. As described in the example, it may be received at three or more locations inside the core member guide portion 24g. Moreover, you may make it receive by one hole part penetrated to the axial direction of a link member like the case of 3rd Embodiment.

  In the description of the second embodiment, the rear end hook 13b of the coil pipe 13 has been described as an example in which it is locked at the most proximal end link member 34 of the bending tube portion 5A. A configuration similar to that of the locking portion 36 may be provided on the end surface 21d of the portion 21A so as to be locked at the connecting portion 21A.

In the description of the second embodiment, the example in which the core member is configured by only the coil pipe 13 has been described. However, in order to improve the slidability with the guide hole 34h, the outer periphery of the coil pipe 13 is formed. A core member covered with a synthetic resin tube or the like may be employed.
Further, in order to adjust the rigidity of the coil pipe 13, a composite body in which a core wire having an appropriate bending rigidity is inserted into the coil pipe 13 may be employed.

  In the description of the third embodiment, an example in which four core members 14 are employed has been described. However, the number of core members 14 is not limited to four as long as there are a plurality of core members 14. For example, in order to form the core member guide hole 37f at an appropriate position, a protrusion similar to the core member guide hole 37f is provided in the cross-shaped hole S, and two, three, five or more core members are provided. 14 may be arranged.

In the description of the first and third embodiments, an example is given in which the shape of the core member guide portion 24g and the core member guide hole 37f is different for each link member. In the drawing, these are drawn as integrated parts, but each link member is not limited to integral molding.
For example, each of the link members 24 and 37 includes a part having a shape common to each link member, and the shape of the inner peripheral portion of the core member guide portion 24g and the shape of the core member guide hole 37f that are different depending on each link member You may comprise as an assembly with another shaped part.

  In addition, all the constituent elements described in the above embodiments and modifications can be appropriately combined and implemented within the scope of the technical idea of the present invention.

For example, as a modification (fifth modification) of the first embodiment, the technical idea of the second embodiment in which a coil pipe is used as a core member may be combined with the first embodiment.
FIG. 13: is a typical front view which shows the modification (5th modification) of the core member which can be used for the bending mechanism of the 1st Embodiment of this invention.
In this modification, instead of the core member 10 of the first embodiment, a coil pipe 15 whose outer shape has the same gradient as the core member 10 as shown in FIG.
The coil pipe 15 has a continuously increased rigidity by increasing the coil winding diameter of an elastic wire having a uniform cross section from the distal end side toward the proximal end side. A distal end hook 13a and a rear end hook 13b are provided at the distal end side and proximal end side of the coil pipe 15, respectively.
In order to apply such a coil pipe 15 to the bending mechanism 1, instead of the tip portion 6 and the connection portion 21, the tip portion 6A and the connection portion 21A of the second embodiment are used, and the end portion of the link member 24N is used. In this case, the rear end hook 13b of the coil pipe 15 may be locked using the locking member 35 of the second embodiment.
As described above, when changing the coil winding diameter to change the rigidity, the coil pipe 15 does not need to change the winding interval. However, in order to give a change depending on the rigidity, the winding interval may be further changed.

  Further, for example, a coil pipe in which the coil winding diameter is changed stepwise instead of the core members 11 and 12 by combining the third and fourth modifications of the first embodiment and the second embodiment. May be adopted.

1, 1A, 1B, 1C Bending mechanism 3, 3A, 3B, 3C Insertion portion 4, 4A, 4B Flexible tube portion 5, 5A, 5B, 5C Curved tube portion 6, 6A, 6B Tip portion 10, 10A, 11, 12, 14, 16 Core member 10c Hollow portion 12c Hollow hole portions 13, 15 Coil pipe (core member)
21, 21A, 21B Connecting portions 21a, 24f Wire insertion holes 24, 24A, 24B, 24C, 24N, 34, 37 Link member 24e Strut portion 24g Core member guide portion 24h Tip side guide hole (core member guide hole)
24i Base end side guide hole (core member guide hole)
24j Escape space 26, 26A, 26B, 26C, 26D Operation wire 34h Guide hole (core member guide hole)
37e guide part 37f core member guide hole 40 imaging part 41 light guide 42 treatment instrument channel 44 tube member H hole part O central axis S cross-shaped hole part

Claims (15)

A distal end portion, a bending tube portion having a plurality of link members coupled to be rotatable, one end side of which is connected to the distal end portion, and one end connected to the distal end portion, and advance and retreat inside the bending tube portion. A bending mechanism comprising: an operation wire for bending the bending tube portion; and a core member that is inserted through the bending tube portion and resists bending of the bending tube portion.
Each of the plurality of link members is
A wire insertion hole through which the operation wire is inserted so as to advance and retreat, and an insertion position of the core member is positioned in a cross section orthogonal to the central axis of the bending tube portion, and the core member is slidably held in the axial direction. A core member guide hole,
The core member is
A bending mechanism characterized in that rigidity is increased from the one end side to the other end side of the bending tube portion.   The bending mechanism according to claim 1, wherein the rigidity of the core member is increased stepwise.   2. The bending mechanism according to claim 1, wherein the core member is a beam member having a second moment of section increasing from the one end side toward the other end side of the bending tube portion.   The bending mechanism according to claim 3, wherein the beam member is a hollow member.   The bending mechanism according to claim 1, wherein the core member is a beam member whose bending elastic coefficient is increased from the one end side to the other end side of the bending tube portion.   The bending mechanism according to claim 5, wherein the bending elastic modulus of the beam member is increased by changing a density of a material used for the beam member. The beam member is composed of a composite material in which a plurality of materials are combined,
The bending mechanism according to claim 5, wherein the bending elastic modulus of the beam member is increased by changing a composite ratio of the plurality of materials. The core member is composed of a coil pipe in which a wire having a uniform cross section is coiled,
The bending mechanism according to claim 1, wherein the rigidity of the core member is increased by changing a winding interval of the wire. The core member is composed of a coil pipe in which a wire having a uniform cross section is coiled,
The bending mechanism according to claim 1, wherein the rigidity of the core member is increased by changing a winding diameter of the wire.   The bending mechanism according to claim 1, wherein the core member is made of a superelastic material having superelasticity.   The bending mechanism according to claim 1, wherein the core member is made of a resin material.   The bending mechanism according to claim 1, wherein the core member is inserted through a center of the bending tube portion.   The bending mechanism according to claim 1, wherein the core member is inserted into a position closer to the center of the bending tube portion in parallel with the operation wire.   The bending mechanism according to claim 1, wherein the core member includes a plurality of core members arranged at an equal angle around a central axis of the bending tube portion.   The bending mechanism according to claim 1, wherein the core member guide hole of the link member receives and holds the core member at a plurality of locations along the axial direction.

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