JPH11267095A - Tubular insert tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bend a bent only at need in this tool having an actuator for operating the bent part to be bent by providing an unnecessary force absorbing means for absorbing the tractive force applied to the bent part when the actuator is not deformed and the tension applied by unnecessary elongation of the actuator. SOLUTION: In an insertion portion 3 of a catheter, a bent part 11 is disposed in the tip part of a flexible tube part 10, and a multi-lumen tube 12 is disposed in the flexible tube part 10. A multi-lumen tube 15 softer than the multi-lumen tube 12 is disposed in the bent part 11. Three sets of shape memory alloy wires 23 are used as a bending actuator for the bent part 11. In this case, the wire folded part 23a of each shape memory alloy wire 23 is held in a slide space 22, thereby forming an unnecessary force absorbing means 27 for absorbing unnecessary force applied to the bent part 11 with the deformation of the insertion portion 3 when the actuator part of the wire 23 is not deformed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as a small-diameter medical catheter to be inserted into a body cavity through an endoscope or into a blood vessel, for example, and the tip of an insertion portion to be inserted into the body cavity. The present invention relates to a tubular insert having a small bending mechanism on the side.

[0002]

2. Description of the Related Art Generally, a small-diameter tubular insertion tool used as a medical catheter has a bending portion which can be bent and deformed at the distal end of the insertion portion of the tubular insertion tool inserted into a body cavity. I have. Conventionally, as a small-diameter bending mechanism for performing a bending operation on the bending portion, a configuration using a shape memory alloy wire as a bending actuator as disclosed in Japanese Patent Application Laid-Open No. 6-63004 is known.

[0003] Here, for example, two sets of wire arranging holes are formed in the tube wall portion of the tubular insertion tool in pairs. These wire arranging holes extend over substantially the entire length along the axial direction of the tubular insertion tool.

Further, the shape memory alloy wire is folded at a central portion, and two wire components on both sides of the folded wire portion are provided with two wires of each set of the tube wall of the tubular insert. Each is inserted into the hole. Then, the wire folded portion of the shape memory alloy wire is fixed between the respective edges of the two wire disposition holes formed on the end face of the tube wall of the tubular insert.

Further, both ends of the shape memory alloy wire are connected to lead wires via connecting members. This lead wire is connected to a power supply control device that controls the amount of power supply to the shape memory alloy wire.

Further, the two sets of shape memory alloy wires of the curved portion are contracted in length by, for example, being heated, and are expanded and restored to the original length by being cooled by being cooled. It is provided with. The two sets of shape memory alloy wires of the bending portion are normally kept in a non-energized state. In this state, the two sets of shape memory alloy wires of the curved portion are each held in a natural length state having a predetermined length, and the bent portion is held in a straight state extending straight.

[0007] When the bending portion is operated to bend, one of the two sets of shape memory alloy wires is electrically heated. At this time, the shape-memory alloy wire that has been energized and heated is deformed into a state in which its length is contracted, so that the wire-folding portion of the shape-memory alloy wire is pulled toward the hand. As a result, the bending portion of the tubular insertion tool is bent toward the contracting shape memory alloy wire.

[0008]

In the above-mentioned conventional structure, the wire folded portion at the distal end of the shape memory alloy wire used as the bending actuator has two fins formed on the end face of the tube wall of the tubular insert. It is directly fixed between each end of the wire arrangement hole. Therefore, there is no play between the wire turn-back portion of the distal end portion of the shape memory alloy wire and the end face of the tube wall of the tubular insertion tool. The bending of the portion may cause the shape memory alloy wire to be pulled toward the hand side, and the bending portion may be unnecessarily bent against the user's will. Further, at this time, there is a possibility that the fixing portion between the wire folded portion at the distal end portion of the shape memory alloy wire and the end face of the tube wall of the tubular insertion tool may be damaged due to the tensile force acting on the shape memory alloy wire.

[0009] The shape memory alloy wire has a characteristic that, when a stretching operation is repeated while applying a large load, the entire length is elongated. It is conceivable that the shape memory alloy wire, which is the actuator for bending, is slightly stretched while the conventional structure is used. When the length of the shape memory alloy wire is longer than that at the time of the first assembly, extra tension is applied to each portion of the tubular insertion tool, such as a connection portion between the curved portion and the insertion portion, and thereby, Each part of the tubular insertion tool may be damaged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to bend a bending portion only when necessary, and at the time of bending an insertion portion, the bending portion is moved by the user. An object of the present invention is to provide a tubular insertion tool that can reliably prevent unnecessary bending, and can prevent breakage of each part of the tubular insertion tool such as a curved portion.

[0011]

SUMMARY OF THE INVENTION The present invention provides a tubular insertion tool body having an insertion portion to be inserted into a body cavity, and a bendable and deformable bending portion provided on the distal end side of the tubular insertion tool body. ,
An actuator formed of a shape memory alloy wire, for pulling a tube wall of the tubular insert main body by a contraction deformation operation of the shape memory alloy wire, and bending the bending portion in the direction of the shape memory alloy wire, and the actuator And an unnecessary force absorbing means for absorbing a tension acting on each part of the tubular insertion tool by a traction force acting on the curved portion due to the deformation of the insertion portion when the insertion portion is not deformed and an unnecessary extension of the actuator. Is a tubular insertion tool. When the actuator is not deformed, the traction force acting on the curved portion due to the deformation of the insertion portion and the tension acting on each portion of the tubular insertion tool due to unnecessary extension of the actuator are absorbed by unnecessary force absorbing means, so that the insertion portion is bent. Accordingly, the operation of pulling the shape memory alloy wire of the actuator toward the hand side and the unnecessary elongation of the actuator are absorbed. Thereby, when the bending portion is not bent and the insertion portion is bent, the bending portion is unnecessarily bent against the user's will in conjunction with the bending operation of the insertion portion. And to prevent breakage of each part of the tubular insertion tool due to unnecessary force caused by the actuator.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a catheter (tubular insert main body) 1 which is a tubular insert of the present embodiment.
1 shows a schematic configuration of the whole system of the controller 2.

The catheter 1 according to the present embodiment is provided with an elongated insertion portion 3 inserted into a body cavity, and an extracorporeal arrangement portion 4 on the proximal side which is not inserted into the body cavity. Here, a branch portion 5 is provided in the extracorporeal arrangement portion 4. This branch 5
Is connected to one end of the proximal tube 6 and one end of the distribution cable 7. Further, one end of a treatment tool insertion base 8 is connected to the other end of the proximal tube 6. A treatment tool introduction port 9 is formed at the other end of the treatment tool insertion base 8. The other end of the distribution cable 7 is connected to the controller 2.

The insertion section 3 of the catheter 1 is provided with a bending section 11 which can be bent and deformed at the distal end of an elongated flexible tube section 10. Here, a first multi-lumen tube 12 made of, for example, Teflon and having relatively high hardness is disposed in the flexible tube portion 10.

As shown in FIGS. 2A and 2B, a channel tube insertion hole 13 extends in the axial direction of the first multi-lumen tube 12 along the axial direction. Further, a plurality of, for example, three sets (six in total) of wire arrangement holes 14 are arranged side by side in pairs on the tube wall around the channel tube insertion hole 13 in the circumferential direction. These wire arrangement holes 14 extend substantially in parallel with the channel tube insertion holes 13 along the axial direction.

The bending portion 11 is provided with a second multi-lumen tube 15 made of a resin material softer than the first multi-lumen tube 12, for example, polyurethane.

The second multi-lumen tube 15 has channel tube insertion holes 13 of the first multi-lumen tube 12 and channel tube insertion holes 16 communicating with three sets (six in total) of wire arrangement holes 14 respectively.
And three sets (six in total) of the wire arrangement holes 17 are respectively formed.

Further, a channel tube 18 is provided at the axial center of the catheter 1 according to the present embodiment, as shown in FIGS. 2 (A) and 2 (B). The channel tube 18 is formed of, for example, a resin material such as Teflon.
The channel tube 18 is inserted into the channel tube insertion hole 16 of the second multi-lumen tube 15 and the channel tube insertion hole 13 of the first multi-lumen tube 12.

The distal opening 18a of the channel tube 18 is disposed at the distal end of the catheter 1. Further, the base end of the channel tube 18 is connected to the branch portion 5.
And is connected to the proximal tube 6 via the. Then, the channel 1 through which a small-diameter endoscope, a treatment tool, or the like is inserted, for example, is inserted by a tube lumen portion of the channel tube 18.
9 are formed. The channel 19 extends from the distal end opening 18a formed at the distal end of the catheter 1 to the insertion portion 3.
Through the inside, the inside of the branch portion 5 and the inside of the proximal tube 6, it is communicated with the treatment instrument introduction port 9 of the treatment instrument insertion base 8. Then, a small-diameter endoscope or a treatment tool inserted into the channel 19 from the treatment tool introduction port 9 of the treatment tool insertion base 8 can be projected outward from the distal end opening 18a of the distal end portion of the catheter 1. It has become.

A flange-shaped spacer 20 is fixed to the distal end of the channel tube 18. The outer diameter of the spacer 20 is set to be substantially the same as the outer diameter of the second multi-lumen tube 15.

Further, the outer peripheral surface of the curved portion 11 of the catheter 1 of the present embodiment is covered with a thin tube 21 made of, for example, silicone. The front end of the thin tube 21 extends to the front of the spacer 20 of the channel tube 18, and is fixed to the outer peripheral surface of the channel tube 18 at a position in front of the spacer 20. A ring-shaped slide is formed in the thin tube 21 between the outer peripheral surface of the channel tube 18 and the spacer 20 of the channel tube 18 and the distal end surface of the second multi-lumen tube 15. A space 22 is formed.

In the catheter 1 according to the present embodiment, three sets of shape memory alloy wires (SMA wires) 23 are used as the bending actuator of the bending portion 11. These shape memory alloy wires 23 have a two-way shape memory effect in which, for example, the length shrinks when heated and then cools to extend and restore the original length.

Each set of shape memory alloy wires 23 has one
The wire strands of the shape memory alloy are folded back at the center portion, and the two wire components 23b and 23c on both sides of the folded wire return portion 23a are connected to each set of wires of the second multi-lumen tube 15. The wires are inserted into the wire mounting holes 14 of each set of the mounting hole 17 and the first multi-lumen tube 12.

Further, the two wire components 23b and 23c of each set of the shape memory alloy wires 23 have an actuator portion 24 functioning as a shape memory alloy at the distal end side.
Are arranged, and a lead wire portion 25 functioning as a lead wire is arranged behind these actuator portions 24. Here, the lead wire portion 25 erases the shape memory of the shape memory alloy by overheating the wire wire of the shape memory alloy, leaving only the function as a lead wire for energization. Then, as shown in FIG. 2 (B), the actuator part 24 on the distal end side of the two wire components 23b and 23c of each of these sets of shape memory alloy wires 23.
The boundary between the lead wire portion 25 on the rear end side is bonded and fixed to the inner peripheral surface of each set of wire arrangement holes 14 of the first multi-lumen tube 12 via an adhesive 26. The boundary between the actuator portion 24 and the lead wire portion 25 on the rear end side of each set of shape memory alloy wires 23 is connected to each set of wires of the first multi-lumen tube 12 via a separate caulking member. It may be configured to be fixed to the inner peripheral surface of the arrangement hole 14.

The lead wire portion 25 of each set of shape memory alloy wires 23 is connected to the controller 2 via the wiring cable 7.
Is connected to an unillustrated energization control device. The amount of energization of each set of shape memory alloy wires 23 to the actuator section 24 is controlled by an energization control device in the controller 2.

Here, the actuator section 24 of each set of the shape memory alloy wires 23 of the bending section 11 is normally kept in a non-energized state. In this state, the actuator portions 24 of each set of shape memory alloy wires 23 are held at the same length, and the curved portion 11 is held in an initial state of a straight linear shape.

Further, when the bending section 11 is operated to bend, the actuator section 24 of each set of shape memory alloy wires 23 is used.
One or two of them are electrically heated. At this time, the actuator portion 24 of the shape-memory alloy wire 23 that has been electrically heated is deformed into a state in which the length is contracted, so that the wire-folding portion 23a of the shape-memory alloy wire 23 is pulled toward the hand side.
The tension force causes only the second multi-lumen tube 15 that is softer than the first multi-lumen tube 12 to be bent toward the actuator portion 24 of the shape memory alloy wire 23 that contracts. The bending section 11 is operated to bend.

The wire folded portion 23a of each set of the shape memory alloy wire 23 is provided between the thin tube 21 and the outer peripheral surface of the channel tube 18 and between the spacer 20 of the channel tube 18 and the second multi-lumen. The catheter 1 is slidably accommodated in a slide space 22 between the distal end surface of the tube 15 and the axial direction of the catheter 1. Here, the actuator section 24 of each set of the shape memory alloy wires 23 of the bending section 11 is held in a non-energized state, and the bending section 11
Is held in a straight line extending straight, the wire folded portion 23 of each set of shape memory alloy wires 23
a is held in the slide space 22 so as to protrude by a predetermined length. Then, when the actuator portion 24 of the shape memory alloy wire 23 is not deformed, the shape memory alloy wire 2
3 when the traction force or the protruding force acts on the slide space 2
By the sliding operation of the wire turn-back portion 23a in 2, the traction force and the protruding force to the shape memory alloy wire 23 are absorbed. Thereby, when the actuator portion 24 of the shape memory alloy wire 23 is not deformed, the insertion portion 3
An unnecessary force absorbing means 27 for absorbing unnecessary force acting on the curved portion 11 due to the deformation of is formed.

When the shape memory alloy wire repeatedly expands and contracts under a load, the entire length of the shape memory alloy wire may be elongated. In the present embodiment, too, the bending operation of the catheter 1 is repeated during the bending operation. Shape memory alloy wire 2
3, elongation may occur. When unnecessary elongation occurs in the shape memory alloy wire 23, there is a possibility that unnecessary tension acts on each part of the catheter 1 such as the curved part 11 of the catheter 1 and a connection part between the curved part 11 and the insertion part 3. However, this unnecessary tension is also absorbed by the unnecessary force absorbing means 27.

The method of setting the protruding length (slide amount) of the wire turn-back portion 23a in the slide space 22 is as follows. That is, when the bending portion 11 is bent as shown in FIG. 3, the length of the bending portion 11 is different between the inside and the outside of the curve, and the outside is long. Then, as the outside of the curve becomes longer, it is necessary to set the projecting length of the wire turn-back portion 23a in the slide space 22 longer in the outer shape memory alloy wire 23.

Therefore, the projecting length of the wire turn-up portion 23a must be at least as large as the increase in the length outside the curve. Here, the length of the bending portion 11 when it is not bent is L, the target bending angle θ of the bending portion 11 is 45 °, the elongation of the bending portion 11 is ΔL, from the center O of the catheter 1 to the shape memory alloy wire 23. L = (2π / 8) · R and L + ΔL = (2π / 8) · (R + r). Therefore, the lower limit of the extension ΔL of the curved portion 11 is ΔL = (2π / 8) · r = (π / 4) · r, which is the length ΔL required for extension of the curved portion 11 ΔL = (π / 4) ) · R When the target bending angle is A °, ΔL = 2πr × (A / 360) = (π / 180) · r ·
A

The setting of the upper limit of the elongation ΔL of the curved portion 11 is as follows. That is, the slide space 22 provided at the distal end of the catheter 1 is made of a hard member. Here, if the rigid portion on the distal end side of the curved portion 11 is long, the insertability of the catheter 1 is significantly reduced. for that reason,
In the catheter 1 of the present embodiment, the length of the slide space 22 is empirically set to be 1/4 or less of the length of the curved portion 11. An embodiment set in accordance with the above description is as follows.

(Example) Overall length of catheter 1: 1.5
m, outer diameter φ: 1.5 mm (distance r between the center of the catheter 1 and the shape memory alloy wire 23: 0.525 mm),
Length of bending portion 11: 16 mm, shape memory alloy wire 23
Is 0.075 mm and the length is 3 m, the lower limit of the slide space 22 of the catheter 1 is about 0.4 m.
m and the upper limit is 4 mm.

Next, the operation of the above configuration will be described.
In the catheter 1 according to the present embodiment, the elongated insertion portion 3 is inserted into a body cavity through an endoscope, for example, or into a blood vessel. Here, the actuator portions 24 of the three sets of shape memory alloy wires 23, which are the bending actuators of the bending portion 11, are always kept in a non-energized state. In this state, the actuators 2 of each set of shape memory alloy wires 23
4 are held at the same length, and the curved portion 11 is held in an initial state in which it extends straight.

When bending the bending portion 11 during the insertion of the insertion portion 3 of the catheter 1, the controller 2 is operated. Then, in accordance with the operation of the controller 2, an unillustrated energization control device in the controller 2 is controlled. At this time, as indicated by the operation of the controller 2 in the energization control device, the actuator portion 2 of the shape memory alloy wire 23 in the bending operation direction of the bending portion 11 is
The energization is performed by the amount indicated in 4.

In this case, any one of the sets of the actuator portions 24 of the shape memory alloy wires 23 or 2
The set is energized and heated. At this time, the actuator portion 24 of the shape memory alloy wire 23 heated and energized is deformed into a state in which the length is contracted.
The third wire folded portion 23a is pulled toward the hand side. The tension force causes only the second multi-lumen tube 15 that is softer than the first multi-lumen tube 12 to be bent toward the actuator portion 24 of the shape memory alloy wire 23 that contracts. The bending section 11 is operated to bend.

When the energization heating of the shape memory alloy wire 23 to the actuator 24 is stopped, the actuator 24 is cooled and thus stretches to its original length. Therefore, in this state, the actuator portions 24 of the three sets of shape memory alloy wires 23 of the bending portion 11 are held at the same length, and the bending portion 11 is returned to the initial state in which it has been straightened.

When the insertion section 3 is deformed while the actuator sections 24 of the three sets of shape memory alloy wires 23 of the bending section 11 are held in the undeformed initial state, the insertion section 3 With the deformation operation, a pulling force pulling toward the hand side and a projection force projecting toward the distal end side act on the shape memory alloy wires 23 of each set of the bending portion 11. In this case, the unnecessary force absorbing means 27 of the present embodiment operates as follows.

That is, due to unnecessary force acting on each set of the shape memory alloy wires 23 of the bending portion 11, the wire turn-back portion 23 a of each set of the shape memory alloy wires 23 is held in the slide space 22 at the distal end of the catheter 1. Side or tip side. Unnecessary force acting on each set of the shape memory alloy wires 23 of the bending portion 11 is absorbed by the sliding operation of the wire turning portion 23a at this time.

Therefore, the above configuration has the following effects. That is, in the present embodiment, the catheter 1
A slide space 22 is provided at the distal end of the slide space 2.
2 is slidably housed in the shape memory alloy wire 23 when the bending portion 11 is not bent and the insertion portion 3 is bent, or when the shape memory alloy wire 23 is unnecessarily stretched during use. In addition, unnecessary force acting on the shape memory alloy wires 23 of each set of the bending portion 11 can be absorbed by the sliding operation of the wire turning portion 23a at this time. Therefore, breakage of each part of the catheter 1 such as the curved portion 11 can be prevented. further,
When the bending portion 11 is not bent and the insertion portion 3 is bent, the bending portion 11 bends unnecessarily against the user's will in conjunction with the bending operation of the insertion portion 3. Can be prevented.

In this embodiment, a flange-shaped spacer 20 is fixed to the distal end of the channel tube 18.
In the tube of the thin tube 21 covering the outer peripheral surface of the curved portion 11 of the catheter 1, between the outer peripheral surface of the channel tube 18 and the spacer 2 of the channel tube 18
Since the ring-shaped slide space 22 is formed between the front end surface of the second multi-lumen tube 15 and the front end surface of the second multi-lumen tube 15, each set of the shape memory alloy wire 23 of the curved portion 11 is formed in the ring-shaped slide space 22. The entire wire turn-back portion 23a can be inserted. Therefore, the configuration of the slide space 22 of the catheter 1 can be simplified as compared with a case where a plurality of slide spaces for individually accommodating the wire folded portions 23a of the shape memory alloy wires 23 of each set of the curved portion 11 are formed. Therefore, processability is good and economical.

The slide space 22 is provided with a spacer 20.
, The channel tube 18 and the distal end surface of the second multi-lumen tube 15, but as shown in FIG. 2C, a spacer portion 98, a tube portion 97, and a folded portion 96. Alternatively, a configuration may be adopted in which the tip member 99 in which are integrated is inserted into the channel tube 18. In this case, the tip member 99 is made of a hard insulator such as ceramic. With such a configuration, it is not necessary to adjust the length of the slide space 22 during assembly, and the assembly is facilitated. Further, since the distal end member 99 is hard, the distal end surface of the second multi-lumen tube 15 using a relatively soft material can be protected from the pulling force of the shape memory alloy wire 23.

In the above embodiment, the boundary between the actuator section 24 on the front end side and the lead wire section 25 on the rear end side of each set of shape memory alloy wires 23 is defined by each of the first multi-lumen tubes 12. The configuration in which the inner peripheral surfaces of the pairs of wire disposing holes 14 are respectively adhered and fixed via an adhesive 26 is shown. It is not always necessary to adhere the boundary between the portion 25 and the inner peripheral surface of each set of wire arrangement holes 14 of the first multi-lumen tube 12 with an adhesive. In this case, the shape memory alloy wire 23 may be deformed by the entire shape memory alloy wire 23 without forming the lead wire portion 25 for energization by overheating as in the above-described embodiment.

FIG. 4 shows a second embodiment of the present invention. In this embodiment, the configuration of the catheter 1 of the first embodiment (see FIGS. 1 to 3) is changed as follows.

That is, in this embodiment, a substantially cylindrical tip member 31 is provided on the outer peripheral surface of the tip of the channel tube 18. On the outer peripheral surface of the tip member 31, there are formed the same number of groove-shaped notches 32 as the number of the wire folded portions 23a of the shape memory alloy wire 23 disposed on the curved portion 11.

Further, the opening of the notch 32 of the tip member 31 is covered with the thin tube 21. The distal end member 31 is provided in the thin tube 21.
A plurality of slide spaces 33 for individually and slidably accommodating the wire turn-back portions 23a of the shape memory alloy wires 23 of each set of the curved portion 11 are formed in the notch portion 32.

Therefore, in the present embodiment, the thin tube 2
The wire turn-over portion 23a of the shape memory alloy wire 23 of each set of the curved portion 11 is provided in the slide space 33 in the first tube.
Are slidably accommodated, and when the insertion section 3 is bent in a state where the bending section 11 is not bent, the sliding operation of the wire turning section 23a at this time stores the shape memory of each set of the bending section 11. The tensile force acting on the alloy wire 23 can be absorbed. Therefore, breakage of the curved portion 11 can be prevented. Furthermore, when the bending portion 11 is not bent and the insertion portion 3 is bent, the bending portion 11 is unnecessarily bent against the user's intention in conjunction with the bending operation of the insertion portion 3. Can be prevented.

In the present embodiment, an insulating partition wall 34 is formed between the notches 32 adjacent to the tip member 31. Therefore, there is also an effect that the partition wall 34 can reliably prevent a short circuit due to direct contact between the wire folded portions 23a of the adjacent shape memory alloy wires 23. In addition, the partition wall 34 is the tip member 31.
Alternatively, it may be constituted by a separate member.

FIG. 5 shows a modification of the second embodiment (see FIG. 4). In this modification, a plurality of holes 35 for forming a slide space 33 are provided on the distal end surface of the distal end member 31 instead of the cutout portion 32 on the outer peripheral surface of the distal end member 31 in the second embodiment. . Each of the hole portions 35 of the distal end member 31 accommodates a wire turn-back portion 23a of each set of the shape memory alloy wires 23 disposed on the bending portion 11 so as to be individually slidable.

Therefore, in the present embodiment, the wire folded portions 23a of the respective sets of the shape memory alloy wires 23 of the curved portion 11 are slidably accommodated in the slide space 33 formed by the respective holes 35 of the distal end member 31. Because
When the bending portion 11 is not bent and the insertion portion 3 is bent, the pulling force acting on the shape memory alloy wires 23 of each set of the bending portion 11 by the sliding operation of the wire turning portion 23a at this time is used. Can be absorbed. Therefore, breakage of each part of the catheter 1 such as the curved portion 11 can be prevented. Furthermore, when the bending portion 11 is not bent and the insertion portion 3 is bent, the bending portion 11 is unnecessarily bent against the user's intention in conjunction with the bending operation of the insertion portion 3. Can be prevented.

In the present embodiment, an insulating partition wall 36 is formed between adjacent holes 35 of the distal end member 31. Therefore, there is also an effect that the partition wall 36 can reliably prevent a short circuit due to direct contact between the wire turn-back portions 23a of the adjacent shape memory alloy wires 23.

FIG. 6 shows a third embodiment of the present invention. In this embodiment, the unnecessary force absorbing means 27 of the catheter 1 of the first embodiment (see FIGS. 1 to 3) is used.
Is changed as follows.

That is, in the first embodiment, the unnecessary force absorbing means 27 is provided at the distal end of the insertion section 3 of the catheter 1, whereas in the present embodiment, the proximal end side of the insertion section 3 of the catheter 1 is provided. Unnecessary force absorbing means 41
Is provided.

Here, a small diameter portion 5a is formed in the branch portion 5 of the present embodiment on the side of the connecting portion with the insertion portion 3, and a large diameter portion 5b is formed at the rear end of the small diameter portion 5a. . And
On the outer peripheral surface of the large diameter portion 5 b of the branch portion 5, the same number of groove-shaped notches 42 as the number of the wire folded portions 23 a of the three shape memory alloy wires 23 disposed on the curved portion 11 are formed.

Further, in the present embodiment, the wire folded portion 2 of each shape memory alloy wire 23 provided in the bending portion 11 is used.
The base ends of the two wire components 23b and 23c on both sides of 3a extend to the branch portion 5 side. In addition, each shape memory alloy wire 23 of the present embodiment is
The entire two wire components 23b and 23c on both sides of a are actuator portions that function as a shape memory alloy having a bidirectional shape memory effect. Further, a lead wire 43 such as an enamel wire is connected to a base end of each of the wire components 23b and 23c via a caulking member 44. The outer diameter of the caulking member 44 is larger than the inner diameter of the insertion hole of the shape memory alloy wire 23 at the front end side of the notch 42, and the caulking member 44 is pulled to the front end side by contraction of the shape memory alloy wire 23 or the like. However, the caulking member 44 abuts against the side wall of the distal end of the notch 42 and does not advance any further.

A coil spring-shaped expansion / contraction part 45 is formed in the middle of the lead wire 43. And the branch 5
Each of the notches 42 accommodates a telescopic part 45 of a lead wire 43 connected to the base end of each of the wire components 23b and 23c. Here, the extendable portion 45 of the lead wire 43 is capable of extending and contracting in the axial direction of the catheter 1 in each cutout portion 42 of the branch portion 5. And the lead wire 4 in each notch 42
The unnecessary force absorbing means 41 of the present embodiment is formed by the three elastic portions 45.

Further, the small diameter portion 5 of the branch portion 5 of this embodiment
In a, a plurality of accommodating grooves 46 for individually accommodating connection portions of the caulking members 44 between the base ends of the respective wire components 23b and 23c and the lead wires 43 are formed.
The caulking member 44 between the base end of each of the wire components 23b and 23c and the lead wire 43 is movable along the axial direction of the catheter 1 in each of the accommodation grooves 46.

In the present embodiment, the wire folded portion 2 of each shape memory alloy wire 23 disposed on the curved portion 11 is used.
3a is fixed to the distal end surface of the second multi-lumen tube 15.

Next, the operation of the above configuration will be described.
When the bending portion 11 is operated to bend when the catheter 1 of the present embodiment is used, an energization control device (not shown) in the controller 2 is controlled by the operation of the controller 2 as in the first embodiment. At this time, the energization control device energizes the shape memory alloy wire 23 in the bending operation direction of the bending portion 11 by the amount specified by the operation of the controller 2.

Here, one or two of the sets of shape memory alloy wires 23 are electrically heated. At this time, the shape-memory alloy wire 23 that has been electrically heated is deformed so that its length is contracted, so that the wire turning portion 23a of the shape-memory alloy wire 23 is pulled toward the hand side. Then, only the second multi-lumen tube 15 that is softer than the first multi-lumen tube 12 contracts due to this tensile force.
The bending portion 11 of the catheter 1 is bent in a state where the bending portion 11 is bent toward the third side.

When the heating of the shape memory alloy wire 23 is stopped, the shape memory alloy wire 23 is cooled and thus stretched to its original length. for that reason,
In this state, the three sets of the shape memory alloy wires 2
3 are held at the same length, so that the curved portion 11 is returned to the initial state in which it is straightened.

When the insertion portion 3 is deformed while the three sets of shape memory alloy wires 23 of the curved portion 11 are held in the undeformed initial state, or when the shape memory alloy wires 23 Occurs, each pair of the shape memory alloy wires 23 of the bending portion 11 and the lead wires 43 connected to the wire components 23b and 23c of each pair of the shape memory alloy wires 23 via the caulking member 44 are close at hand. A pulling force acts on the side or the tip side. In this case, the unnecessary force absorbing means 41 of the present embodiment operates as follows.

That is, the tension acting on the lead wires 43 connected to the respective sets of the shape memory alloy wires 23 of the bending portion 11 and the wire components 23b, 23c of the respective sets of the shape memory alloy wires 23 via the caulking members 44. The expansion and contraction portion 45 of the lead wire 43 is stretched along the axial direction of the catheter 1 in each notch 42 of the branch portion 5 of the catheter 1 by the force. Then, the tensile force acting on each set of the shape memory alloy wires 23 of the bending portion 11 is applied to the lead wires 43 at this time.
Is absorbed by the stretching operation of the expansion and contraction portion 45. Further, when the force acting on the lead wire 43 is in the opposite direction, unnecessary force is absorbed by the contracting operation of the expansion and contraction portion 45.

Therefore, in this embodiment, since the expansion and contraction portion 45 of the lead wire 43 is accommodated in each cutout portion 42 of the branch portion 5 on the hand side of the catheter 1, the bending portion 11 is not bent. When the insertion section 3 is curved, the catheter 1
Of the lead wire 43 in each notch 42 of the branch portion 5
5 by bending or contracting operation
Unnecessary force such as a tensile force acting on each set of shape memory alloy wires 23 can be absorbed. Therefore, in the present embodiment, it is possible to prevent breakage of each part of the catheter 1 such as the curved portion 11 as in the first embodiment. Furthermore, when the bending portion 11 is not bent and the insertion portion 3 is bent, the bending portion 11 is unnecessarily bent against the user's intention in conjunction with the bending operation of the insertion portion 3. Can be prevented.

Further, in this embodiment, an insulating partition wall 47 is formed between the respective accommodating grooves 46 of the small diameter portion 5a of the branch portion 5. Therefore, each of the adjacent wire components 23
There is also an effect that the partition wall 47 can reliably prevent a short circuit due to direct contact between the caulking members 44 between the base ends of the b and 23c and the lead wire 43.

FIG. 7 shows a fourth embodiment of the present invention. In the present embodiment, the configuration of the unnecessary force absorbing means 41 of the catheter 1 of the third embodiment (see FIG. 6) is changed as follows.

That is, in the unnecessary force absorbing means 51 of the present embodiment, a ring-shaped notch 52 is formed on the outer peripheral surface of the large diameter portion 5b in the branch portion 5 of the catheter 1. The cutout portion 52 accommodates a telescopic portion 45 of a lead wire 43 connected to the base end of each of the wire components 23b and 23c of the three shape memory alloy wires 23 provided in the curved portion 11.

Also, on the outer peripheral surface of the small-diameter portion 5a in the branch portion 5, the same number of groove-shaped notches 53 as the number of the wire folded portions 23a of the three shape memory alloy wires 23 provided in the curved portion 11 are formed. Have been. In this notch 53, a caulking member 44 between the base end of the two wire components 23b and 23c on both sides of the wire turn-back portion 23a of each shape memory alloy wire 23 and the lead wire 43 is provided with the axial center of the catheter 1. It is accommodated movably along the direction.

Further, the base ends of the two wire components 23b and 23c provided in each cutout 53 and the lead wire 4
A transparent insulating tube 54 is mounted around the connection between the first and third tubes. Then, the two wire components 2 arranged in each notch 53 by the insulating tube 54
The connection between the base ends of 3b and 23c and the lead wire 43 is prevented from coming into contact with each other and causing a short circuit.

Therefore, in the present embodiment having the above-described configuration, since the expansion and contraction portion 45 of the lead wire 43 is accommodated in the cutout portion 52 of the branch portion 5 on the proximal side of the catheter 1, the bending portion 11 is not bent. Then, when the insertion portion 3 is curved,
Within the notch 52 of the branch portion 5, the expansion and contraction portion 4 of the lead wire 43 is provided.
5 by bending or contracting operation
Unnecessary force acting on each set of shape memory alloy wires 23 can be absorbed. Therefore, in the present embodiment as well as in the third embodiment, the bending portion 11 can be prevented from being damaged, and when the bending portion 11 is not bent and the insertion portion 3 is bent, It is possible to prevent the bending portion 11 from unnecessarily bending against the user's intention in conjunction with the bending operation of the insertion portion 3.

FIGS. 8 to 10 show a fifth embodiment of the present invention. In this embodiment, the configuration of the catheter 1 of the first embodiment (see FIGS. 1 to 3) is changed as follows.

That is, in the present embodiment, the catheter 1
The contact sensor 61 is provided at the tip of the insertion section 3 in FIG. Here, a hard distal member 62 is provided at the distal end of the insertion section 3 of the catheter 1 as shown in FIG. A tapered tapered surface 63 is formed on the outer peripheral surface of the distal end portion of the distal end member 62.

The contact sensor 61 is provided with a thin film strain sensor 64 as shown in FIG. The thin film strain sensor 64 is bonded to the outer peripheral surface of the distal end portion of the distal end member 62 with a silicon adhesive 65. When the silicon adhesive 65 is cured, an elastic body is formed between the thin film strain sensor 64 and the outer peripheral surface of the distal end portion of the distal end member 62. Further, a substantially hemispherical pressure receiving portion 66 is protruded from the outer surface of the thin film strain sensor 64.

In this embodiment, when the pressure receiving portion 66 at the distal end of the catheter 1 receives a pressing force, the strain sensor 64 is deformed together with the elastic body of the silicone rubber in which the silicone adhesive 65 is hardened. At this time, the distortion sensor 64 outputs a deformation amount (distortion amount), and a processing circuit (not shown) in the controller 2 connected to the distortion sensor 64 converts the output into a pressing force. Then, the controller 2 bends the bending portion 11 so as to avoid the pressing force.

FIG. 10 shows, as an example of the operation of the catheter 1, a state in which the insertion portion 3 of the catheter 1 is inserted into a human blood vessel. Here, the insertion section 3 of the catheter 1 is inserted from an artery of a human thigh (not shown), and advances through an artery 71 toward a heart (not shown). Before the artery 71 reaches the heart, the aortic arch 72
It is greatly curved. In addition, the artery 71 branches into several parts at the aortic arch 72 and connects to a blood vessel 73 heading to the head.

When the insertion portion 3 of the catheter 1 is inserted into the aortic arch 72 and is advanced, the distal end member 62 of the catheter 1 is moved in a direction shown by a solid line in FIG. Hit. At this time, the contact sensor 61 of the tip member 62 detects the pressing value, and performs the above-described series of pressing avoiding bending operations. By this operation, the insertion portion 3 of the catheter 1 is curved in a direction to avoid pressing against the blood vessel wall as shown by a dotted line in FIG. 10, and thereafter, the insertion is smoothly performed.

Therefore, the above configuration has the following effects. That is, the contact sensor 61 is provided with the thin film strain sensor 64, and when the pressure receiving portion 66 at the distal end of the catheter 1 receives a pressing force, the strain sensor 64 is formed together with the elastic body of the silicone rubber in which the silicone adhesive 65 is cured. By deforming, the output of the deformation amount from the strain sensor 64 is converted into a pressing force, and the controller 2 bends the bending portion 11 so as to avoid the pressing force. The curved catheter 1 can be realized.

FIGS. 11A to 11C show a first modification of the state of attachment of the contact sensor 61 in the catheter 1 of the fifth embodiment (see FIGS. 8 to 10). . In this modified example, as shown in FIG. 11B, a sensor mounting groove portion 81 of a deep groove is formed in a portion corresponding to the mounting portion of the contact sensor 61 on the outer peripheral surface of the hard tip member 62 of the fifth embodiment. I have. As shown in FIG. 11C, a silicon adhesive 65 similar to that of the fifth embodiment is embedded in the sensor mounting groove 81, and the thin film strain sensor 64 of the contact sensor 61 is attached thereon. .

Therefore, in this modification, the sensor mounting groove 81 of the deep groove is provided in a portion corresponding to the mounting portion of the contact sensor 61 on the outer peripheral surface of the tip member 62, so that the silicon rubber 65 of the silicon adhesive 65 for receiving the contact sensor 61 is provided. Can be increased. Therefore, since the amount of the elastic body of the silicon adhesive 65 that receives the contact sensor 61 is large, the contact sensor 6
The amount of deformation of the thin film strain sensor 64 can be increased. As a result, since the sensor sensitivity of the contact sensor 61 in the catheter 1 can be increased, it is possible to perform highly sensitive insertion to avoid pressing.

FIGS. 12A and 12B show a second modification of the contact sensor 61 in the catheter 1 according to the fifth embodiment (see FIGS. 8 to 10). . In this modification, a rounded chamfered portion 91 is formed on the outer peripheral edge of the distal end portion of the distal end member 62, and the pressure receiving portion 66 of the contact sensor 61 is arranged at the chamfered portion 91. In this modification, the same effects as in the fifth embodiment can be obtained.

FIG. 13 shows a sixth embodiment of the present invention. In this embodiment, a curved portion 1 of the catheter 1 according to the first embodiment (see FIGS. 1 to 3) is used.
The configuration of the shape memory alloy wire (SMA wire) 23 used as the first bending actuator is changed as follows.

That is, in the first embodiment, one wire wire of the shape memory alloy is folded at the central portion, and the folded wire folded portion 23 a is inserted into the slide space 22 in the axial direction of the catheter 1. In the present embodiment, the distal end of the linear shape memory alloy wire 101 is protruded into the slide space 22 and the lead extends from the hand side. Line 1
02 is connected to the protruding end via a caulking member 103 while being caulked and fixed.

In the bending operation of the bending portion 11 of the present embodiment, the shape memory alloy wire 101 and the lead 1
02, the shape memory alloy wire 101 is electrically heated. At this time, the shape-memory alloy wire 101 that has been energized and heated is deformed into a state in which the length is reduced, so that the caulking member 103 at the distal end of the shape-memory alloy wire 101 is pulled toward the hand. Then, only the second multi-lumen tube 15 that is softer than the first multi-lumen tube 12 contracts due to this tensile force.
The bending section 11 of the catheter 1 is bent in a state where the bending section 11 is bent toward one side.

When the insertion section 3 is deformed while the three sets of shape memory alloy wires 101 of the bending section 11 are held in the undeformed initial state, the deformation operation of the insertion section 3 is performed. Accordingly, a pulling force acts on the pair of shape memory alloy wires 101 of the bending portion 11 toward the hand side.
In this case, the caulking member 103 at the distal end of each set of shape memory alloy wire 101 is moved by the tensile force acting on each set of shape memory alloy wire 101 of the bending portion 11 in the sliding space at the distal end of the catheter 1. Slide to the inside in 22. Then, the tensile force acting on each set of shape memory alloy wires 101 of the bending portion 11 is absorbed by the sliding operation of the caulking member 103 at this time.

Therefore, the above configuration has the following effects. That is, in the present embodiment, the catheter 1
A slide space 22 is provided at the tip of the wire, and the caulking member 103 at the end of the shape memory alloy wire 101 is slidably housed in the slide space 22.
When the insertion portion 3 is bent or the shape memory alloy wire 101 is unnecessarily elongated in a state where the bending operation of the bending portion 11 is not performed, the sliding operation of the caulking member 103 at this time causes each of the bending portions 11 to move. Sets of shape memory alloy wires 10
1 can be absorbed by a tensile force or a compressive force. Therefore, breakage of the curved portion 11 and each part of the catheter 1 can be prevented. Furthermore, it is possible to prevent the bending portion 11 from unnecessarily bending against the user's will when the insertion portion 3 is bent in a state where the bending portion 11 is not bent.

Further, in this embodiment, in particular, since the use amount of the shape memory alloy wire 101 is approximately half that of the catheter 1 of the first embodiment, the power consumption can be reduced.

FIG. 14 shows a sixth embodiment (FIG. 13).
1) shows a first modified example of the catheter 1 of FIG. That is, in the present modification, the tip of the linear shape memory alloy wire 101 protruding into the slide space 22 is connected to the tip of the lead wire 102 extending from the hand side, and this knot is connected. 104 are connected in a fixed state by soldering.

Therefore, in this modified example of the above configuration, the caulking member 103 of the sixth embodiment can be omitted, so that the number of components of the entire catheter 1 can be reduced and the configuration can be simplified.

FIG. 15 shows a sixth embodiment (FIG. 13).
2) shows a second modification of the catheter 1). That is, in this modification, the distal ends of the three shape memory alloy wires 101 of the sixth embodiment are connected to the distal end of one common lead wire 102.

Therefore, in this modified example of the above configuration, since only one lead wire 102 of the three shape memory alloy wires 101 of the sixth embodiment is required, the number of components of the entire catheter 1 can be reduced. The configuration can be simplified.

FIG. 16 shows a sixth embodiment (FIG. 13).
3) shows a third modified example of the catheter 1). That is, in this modification, a ring-shaped tip member 111 made of a conductor such as stainless steel is provided at the tip of the second multi-lumen tube 15 of the bending portion 11, and one lead is attached to the tip member 111. This is a connection of the ends of the wires 102. The distal ends of the three shape memory alloy wires 101 of the sixth embodiment are connected to one common lead wire 102 via the distal end member 111.

Therefore, in the present modified example of the above configuration, similarly to the second modified example (see FIG. 15), one lead wire 102 of the three shape memory alloy wires 101 of the sixth embodiment is used. Therefore, the number of components of the entire catheter 1 can be reduced and the configuration can be simplified.

FIG. 17 shows a sixth embodiment (FIG. 13).
4) shows a fourth modified example of the catheter 1 of FIG. That is, in this modification, the heater 121 for heating is provided only in the actuator portion of the shape memory alloy wire strand 101 of the sixth embodiment. The heater 121 is formed of, for example, a semiconductor thin film heater or a nichrome wire. Further, a fixing portion 122 for fixing the base end of the shape memory alloy wire 101 is provided on the tube wall of the catheter 1 of this modification.

Therefore, in this modified example of the above configuration, the shape memory alloy wire strand 101 is heated by the heater 121 for heating.
Since only the actuator portion of the above can be concentratedly heated, it is efficient.

Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention. Next, other characteristic technical matters of the present application will be additionally described as follows. (Additional Item 1) In a tubular insertion tool to be inserted into a body cavity, a bending portion at a distal end of the tubular insertion device, a distal end portion at a distal end of the bending portion, and a distal end passing through a tube wall of the tubular insertion device. A tubular insertion tool comprising: at least one shape memory alloy wire folded back inside the portion; and a slide portion provided at the distal end and having a space in which the folded portion of the shape memory alloy wire can slide. .

(Additional Item 2) In addition to the above requirements, the outer diameter of the catheter is φ1.5 mm, the length of the curved portion is 16 mm, the total length is 1.5 m, and the outer diameter of the shape memory alloy wire is φ0.07.
The tubular insertion tool according to claim 1, wherein when the length is 5 mm and the length is 3 m, the length of the slide portion is 0.4 mm or more and 4 mm or less.

(Additional Item 3) When the distance from the center of the catheter to the actuator is r, and the target bending angle is A °, the lower limit of the length of the slide portion is πrA / 180.
Further, when the length of the curved portion is L, the upper limit value of the length of the slide portion is L / 4, and when the upper limit value is lower than the lower limit value, the length of the slide portion uses the above lower limit value. 3. The tubular insertion tool according to claim 1, wherein

(Additional Item 4) An additional item characterized in that a slide portion having a space in which a connecting portion between the shape memory alloy wire and the lead wire can slide in the longitudinal direction is provided also at the rear end of the shape memory alloy wire. 1 tubular insert.

(Conventional Techniques of Additional Items 1 to 4) Conventionally,
There is a small-diameter bending mechanism using a shape memory alloy wire as a bending actuator.

(Problems to be Solved by Additional Items 1 to 4)
In the conventional one, the actuator is directly connected at the tip of the bending part, so there is no play, and when the insertion part is bent,
As a result, there is a problem that the bending portion is bent.

(Objects of Additional Items 1 to 4) Provided is a small-diameter bending mechanism in which a bending portion bends only when necessary.

(Means for Solving the Problems in Additional Items 1 to 4) In a tubular insertion tool to be inserted into a body, a bending portion, a distal end portion at a bending distal end, and a bending portion passing through an insertion tool tube wall. A bending mechanism comprising: at least one shape memory alloy wire folded back at a distal end of the shape memory alloy wire; and a slide portion provided at the distal end and slidable with the folded back portion of the shape memory alloy wire. .

(Effects of Additional Items 1 to 4) When necessary, only the bending portion bends.

(Additional Item 5) In a tubular insertion tool provided with a curved portion at the distal end portion, a distal end portion at a distal end side of the curved portion, a bending actuator for bending the curved portion, and a periphery of the distal end portion. At least one semiconductor thin film strain sensor provided, an elastic member provided between the tip and the semiconductor thin film strain sensor, and signal processing for detecting a pressing force applied to the tip from an output signal from the strain sensor. Means,
Control means for driving the bending actuator in accordance with the pressing force detected by the signal processing means.

(Prior Art in Appendix 5) Conventionally, there is a curved catheter having a bending function at a distal end portion, in which a pressure sensing sensor using a surface emitting laser is provided at the distal end portion.

(Problem to be Solved by Additional Item 5) However, the pressure sensing sensor using the surface emitting laser has a complicated structure and is difficult to miniaturize.

(Purpose of Supplementary Item 5) Provided is a small-diameter curved catheter having a simple structure and a pressure detecting function.

(Effect of Additional Item 5) A pressure-avoidance curved catheter can be realized with a simple configuration.

[0109]

According to the present invention, the traction force acting on the curved portion due to the deformation of the insertion portion when the actuator formed by the shape memory alloy wire is not deformed, and acts on each portion of the tubular insertion tool due to unnecessary extension of the actuator. Unnecessary force absorbing means for absorbing the tension which occurs can bend the bending portion only when necessary, and when the insertion portion is bent, the bending portion is bent unnecessarily against the user's will. It is possible to reliably prevent the tubular insertion tool from being damaged, and to prevent breakage of each part of the tubular insertion tool such as the curved portion.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a schematic configuration of an entire catheter according to a first embodiment of the present invention.

FIG. 2A is a cross-sectional perspective view of a main part showing a curved portion of the catheter of the first embodiment, and FIG. 2B is a cross-sectional view of a main part showing a wire fixing part of the catheter of the first embodiment. FIG. 3C is a perspective view, and FIG. 4C is a cross-sectional perspective view showing the distal end member of the catheter according to the first embodiment.

FIG. 3 is a side view of a main part showing a curved state of the curved portion of the catheter according to the first embodiment.

FIG. 4 is a cross-sectional perspective view of a main part of a catheter according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional perspective view of a main part of a catheter showing a modification of the second embodiment.

FIG. 6 is a perspective view of a main part of a catheter according to a third embodiment of the present invention.

FIG. 7 is a perspective view of a main part of a catheter according to a fourth embodiment of the present invention.

FIG. 8 is a perspective view of a main part of a catheter according to a fifth embodiment of the present invention.

FIG. 9 is a perspective view of a main part showing an attached state of a contact sensor in a catheter according to a fifth embodiment.

FIG. 10 is a perspective view of a main part showing an operation state of the catheter according to the fifth embodiment.

FIG. 11A is a perspective view of a main part showing a first modification of the state of attachment of the contact sensor in the catheter according to the fifth embodiment, and FIG. 11B is an attachment of the contact sensor of the first modification; FIG. 7C is a perspective view showing a groove, and FIG. 9C is a longitudinal sectional view of a main part showing a mounting portion of a contact sensor according to a first modification.

FIG. 12A is a perspective view of a main part showing a second modified example of the state of attachment of the contact sensor in the catheter according to the fifth embodiment, and FIG. 12B is an attachment of the contact sensor of the second modified example; The longitudinal section of the important section which shows the section.

FIG. 13 is a perspective view of a main part of a catheter according to a sixth embodiment of the present invention.

FIG. 14 is a perspective view of a main part showing a first modification of the catheter according to the sixth embodiment.

FIG. 15 is a perspective view of a main part showing a second modification of the catheter according to the sixth embodiment.

FIG. 16 is a perspective view of a main part showing a third modification of the catheter according to the sixth embodiment.

FIG. 17 is a perspective view of a main part showing a fourth modification of the catheter according to the sixth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Catheter (tubular insertion tool main body) 3 Insertion part 11 Bending part 22 Sliding space 23 Shape memory alloy wire 23a Wire turning back part 27 Unnecessary force absorption means

Claims (1)

[Claims] 1. A main body of a tubular insertion tool having an insertion portion to be inserted into a body cavity, a bending portion provided at a distal end side of the tubular insertion tool body, which can be bent and deformed, and formed by a shape memory alloy wire. An actuator for retracting the tube wall of the tubular insertion tool main body by a contraction deformation operation of the shape memory alloy wire to bend the bending portion in the direction of the shape memory alloy wire; and inserting the actuator when the actuator is not deformed. A tubular insertion tool, comprising: unnecessary force absorbing means for absorbing a tension acting on each part of the tubular insertion tool by a traction force acting on the curved portion due to deformation of the portion and unnecessary extension of the actuator.