JPH05184528A - Bending mechanism of flexible tube - Google Patents

Abstract

PURPOSE:To provide the bending mechanism of a flexible tube which can surely assure the thermal stability to a living body with a simple structure. CONSTITUTION:This bending mechanism of the flexible tube has a driving member 10 consisting of a shape memory alloy wire arranged in the flexible tube 1, an angle wire 12 connected to this driving member 10 and a means for electrically heating the driving member 10. The angle wire 12 is arranged within an in-vivo insertion part 13 of the flexible tube 1 which is in contact with the biocavity and the driving member 10 is arranged within the non- insertion part 14 of the flexible tube which is not in contact with the biocavity. One end of this angle wire 12 is fixed to the bending part end of the flexible tube 1 and the other end is connected to the driving member 10. A bending part 4 is operated to be curved by the shrinkage caused by the electrical heating of the driving member 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending mechanism for a flexible tube used in endoscopes, catheters and the like.

[0002]

2. Description of the Related Art Conventionally, as a bending mechanism for a flexible tube such as an endoscope or a catheter, a wire made of a shape memory alloy (hereinafter referred to as SMA wire) is arranged in a loop in a bending portion, and the SMA wire is electrically heated. By doing so, it is known that the SMA wire is contracted to bend the bending portion.

[0003]

However, in the conventional bending mechanism for a flexible tube, the heat generated when the SMA wire is energized is transferred to the living tissue from the outside of the bending portion, which may cause burns on the inner wall of the body cavity. However, there is a problem that it is difficult to secure safety to the living body.

Further, in order to prevent excessive heating, for example, a cooling method for supplying cooling water into the channel of the catheter is used. In this case, it is necessary to provide a pump for supplying cooling water, There is a problem that the structure becomes complicated and the manufacturing cost increases.

The present invention has been made in view of the above problems, and an object thereof is a bending mechanism such as an endoscope or a catheter provided with an SMA wire as an actuator and having a simple structure and thermal safety to a living body. It is to provide a bending mechanism that can secure

[0006]

SUMMARY OF THE INVENTION According to the present invention, a drive member made of a shape memory alloy wire arranged in a flexible tube, an angle wire connected to the drive member, and an electric heating of the drive member are provided. In the bending mechanism of the flexible tube, the angle wire is disposed in a living body insertion portion of the flexible tube that comes into contact with the inside of the living body cavity, and the driving member is not in contact with the living body cavity. Of the angle wire, the one end of the angle wire is fixed to the tip of the bending portion of the flexible tube, the other end is connected to the driving member, and the bending portion is bent by contraction due to electric heating of the driving member. It is characterized by operating.

Therefore, the shape-memory alloy wire that generates heat is not arranged in the living body inserting portion that comes into contact with the body cavity wall.
The flexible tube is bent without transmitting heat to the living body.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a catheter to which a bending mechanism according to the first embodiment of the present invention is applied. The main body of this catheter is formed of a flexible tube 1, and this flexible tube 1 is composed of a polyurethane multi-lumen tube.
The flexible tube 1 is provided with a channel 2 for inserting a small-diameter scope, a guide wire, or the like, and for feeding or sucking liquid. Further, a lumen 3 accommodating the angle wire 12 and the shape memory alloy wire 10 (hereinafter referred to as SMA wire) is formed.

A bending portion 4 is provided on the distal end side of the flexible tube 1 of the catheter, and a jacket tube 11 is covered on the rear side thereof. A pair of the angle wires 1 are provided in the bending portion 4.
2 is inserted into the lumen 3 and is fixed by a caulking portion 5 at the tip of the flexible tube 1. The base end of the angle wire 12 is connected to the SMA wire 10 whose tip is bent in a U-shape at the connecting portion 7. The SMA wire 10 is arranged in the non-living body inserting portion 14 that does not come into contact with the living body cavity. Further, the connecting portion 7 is movably accommodated in a space formed in the driving portion 6.

Angle wire 12 and SMA wire 10
Are generally connected by laser welding, but in addition, S
It is also possible to plate the tip of the MA wire 10 for soldering, or to mechanically bond it. Also, SM
The proximal end of the A wire 10 is connected to the current-carrying wire 8 by the caulking portion 9, and a current is supplied from a current-carrying control device (not shown) connected to the proximal portion of the current-carrying wire 8 to heat the SMA wire. The heat causes the SMA wire to shrink. The SMA wire 10 of this embodiment is made of a bidirectional shape memory alloy, and is made of a Ti-Ni alloy or Cu-Zn-.
Various materials such as Al alloy can be used, but Ti-
Ni alloys are preferred.

The energization control device (not shown) is
The energization amount can be adjusted, and PWM energization is suitable for adjusting the energization amount.

As shown in FIG. 4, the main body of the catheter is composed of three tubes. First, the living body insertion portion 13 of the catheter is made of polyurethane, and as shown in FIG.
As shown in (b), a three-lumen tube of a lumen forming the channel 2 and a lumen 3a through which the angle wire 12 is inserted is used. As shown in FIG. 4 (c), the catheter drive unit 6 has the same catheter outer diameter and channel diameter as the living body insertion unit 13, but the lumen 3b has an elliptical shape, and the connection unit has the same shape. Two SMA wires 10 folded back at 7 can be inserted. However, when the SMA wire 10 becomes longer to some extent, the lumen 3
There is a risk of being entangled in b and causing a short circuit. Therefore,
In the non-living body insertion section 14 other than the drive section 6 of the catheter, as shown in FIG. 4D, the SMA wire 10 is inserted into the lumen 3c one by one. In addition, the non-living body inserting section 14 needs a multi-lumen tube capable of withstanding the heat of the SMA wire 10 during heating by energization. Therefore, a heat-resistant multi-lumen tube such as Teflon is used.

In order to connect the angle wire and the SMA wire easily and surely, the angle wire 15 is formed into a ring shape as shown in FIG. 15 and SM
You may cross and connect with the A wire 16. According to this structure, the main body of the catheter is formed of two types of tubes, the drive unit 19 of the catheter has the same structure as the drive unit 6 shown in FIG. 4C, and the SMA wire 16 can be freely heated by electric heating. Can be expanded and contracted.

Further, the living body inserting portion 17 and the non-living body inserting portion 18
Has a structure as shown in FIG. Since the tip of the angle wire 15 provided in the living body inserting section 17 is covered and fixed with polyurethane, which is the same material as the catheter body, the SMA wire 16 contracts during heating by energization, the angle wire 15 is pulled, and the tip of the catheter is pulled. To bend. In addition to polyurethane, polyethylene, silicone, fluororesin or the like can be used for the catheter body.

Next, the operation of the first embodiment will be described.

FIG. 3 shows a state in which the catheter of this embodiment is inserted into the body cavity such as the pancreatic duct 21 through the channel 24 of the side-viewing endoscope 23.

The SMA wire 10 arranged in this catheter is connected to the current-carrying wire 8 by a current-carrying controller (not shown).
Energize via. As a result, the SMA wire 10
The SMA wire 10 contracts due to electric heating, and the contracting operation of the SMA wire 10 pulls one angle wire 10 to bend the bending portion 4 in a desired direction. It should be noted that the length of the cavity in the drive section 6 of the catheter is such that the connecting section 7 does not contact the end of the cavity even if the SMA wire 10 contracts to the maximum.

The curved portion 4 is more flexible than the other portions because the outer tube 11 is not covered. Therefore, the bending due to the contraction of the SMA wire 10 is limited to only the bending portion 4, and the jacket tube 11 does not bend. In addition, the SMA wire 1 which is heated to high temperature by electric heating
Since 0 is located in the channel 24 of the endoscope 23,
The heat transfer to the outside of the jacket tube 11 is confined in the channels 24. Therefore, since only one angle wire 10 is positioned in the living body insertion portion 13 that contacts the inner wall of the living body and is not heated, the inner wall of the living body is not adversely affected by heat.

FIG. 5 shows a bending portion of an endoscope to which a bending mechanism according to the second embodiment of the present invention is applied.

The main body of the endoscope insertion portion is composed of a multi-lumen tube, the curved portion 35 is made of polyurethane, and the rear side from the drive portion needs heat resistance to withstand the heating of the SMA wire. Is formed by. In addition, the objective lens 30, the light guide fiber 31
The distal end portion 32 of the endoscope to which is fixed is formed of a material such as electrically insulating ceramics or plastic.

A pair of angle wires 26 are inserted into the lumen in the bending portion 35 of the endoscope, and are fixed by the caulking portion 25 at the distal end portion 32 of the endoscope. Further, the proximal side of the angle wire 26 is connected to a SMA wire 28 whose tip is bent in a U shape in a drive section 27 provided in the endoscope insertion section by a connection section 29.
The angle wire 26 and the SMA wire 28 are
Connection is made in the same manner as in the embodiment.

The rear end of the SMA wire 28 is connected to a current-carrying wire (not shown). In addition, the endoscope tip portion 32
The objective lens 30 disposed inside the image guide 33
The image guide 33 extends to the rear eyepiece (not shown). Further, like the image guide 33, the light guide 31 disposed inside the endoscope insertion portion is connected to a light source device (not shown) outside from the endoscope distal end portion 32 through the insertion portion.

In this embodiment, when the SMA wire 28 arranged in the endoscope insertion portion is energized by an energization control device (not shown), the SMA wire 10 contracts due to energization heating, and the SMA wire 10 contracts. The angle wire 26 on one side is pulled, and the bending portion 35 bends in a desired direction. In that case, S which becomes high temperature by electric heating
Since the MA wire 28 is located in the lumen of the endoscope insertion portion, the heat of the SMA wire 28 is retained in the lumen. Therefore, since the outer surface of the insertion portion that contacts the inner wall of the living body is not heated, it is possible to prevent the adverse effect of heat on the inner wall of the living body.

The present invention is not limited to the above embodiments and can be applied to various endoscopes, catheters and the like.

[0026]

As described above, in the bending mechanism of the flexible tube according to the present invention, since the shape memory alloy wire for generating heat is not arranged in the living body inserting portion which comes into contact with the body cavity wall, heat is not transmitted to the living body. The flexible tube can be bent.
Therefore, the thermal and electrical safety to the living body can be reliably ensured with a simple configuration.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a tip portion of a catheter according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a modified example of the tip portion of the catheter shown in FIG.

FIG. 3 is a perspective view showing a usage state of the catheter according to the first embodiment.

4 (a) is an exploded schematic view showing the configuration of the distal end portion of the catheter shown in FIG. 1, (b) is a sectional view of a living body inserting portion,
(C) is a cross-sectional view of a drive unit, and (d) is a cross-sectional view of a living body non-insertion unit.

FIG. 5 is a vertical cross-sectional view showing a distal end portion of an endoscope according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flexible tube, 4 ... Bending part, 10 ... SMA wire (driving member), 12 ... Angle wire, 13 ... Living body insertion part, 14
… Non-living body insertion part.

Claims (1)

[Claims] 1. A flexible tube comprising: a drive member made of a shape memory alloy wire arranged in the flexible tube; an angle wire connected to the drive member; and a means for electrically heating the drive member. In the bending mechanism, the angle wire is disposed in a living body inserting portion of a flexible tube that contacts the inside of a living body cavity, and the driving member is disposed in a non-inserting portion of the flexible tube that is not in contact with the living body cavity, One end of the angle wire is fixed to the tip of the bending portion of the flexible tube, the other end is connected to the driving member, and the bending portion is bent by contraction of the driving member due to electric heating. Bending mechanism.