JP3435227B2 - Endoscope bending section - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending portion of an endoscope which is provided at a distal end of an insertion portion of the endoscope and is bent by remote control.

[0002]

2. Description of the Related Art Generally, a bending portion of an endoscope is constructed by rotatably connecting a large number of joint rings with a rivet and remotely pulling an operation wire attached to the leading end joint ring. , Can be bent arbitrarily.

However, with such a structure, it is extremely difficult to reduce the diameter of the curved portion. Therefore, in order to reduce the diameter of the curved portion, for example, as shown in Japanese Patent Application Laid-Open No. 3-173371, a bending actuator in which a shape memory alloy is formed in a thin flat plate shape is arranged in the curved portion, and the shape actuator is made of the shape memory alloy. The bending actuator was heated by energization to bend the bending portion.

Incidentally, JP-A-1-304416, JP-A-1-315675, and the like also show that a curved portion is bent by using a shape memory alloy. However, since several shape memory alloy springs are arranged in parallel in each case, a large space is required, and it is difficult to reduce the diameter of the curved portion.

[0005]

[Problems to be Solved by the Invention]
In No. 1, a thin plate-shaped curved actuator is formed by depositing a shape memory alloy layer on the surface of an elastic base material made of metal or rubber.

At the current level of technology, however, the shape memory alloy can be thinned to a wire diameter of, for example, about 30 μm without difficulty, but it is very difficult to process it into a thin flat plate. is there. Therefore, in reality, it is difficult to reduce the diameter of the curved portion by using the flat shape memory alloy actuator.

[0007] Therefore, an object of the present invention is to provide a bending portion of an endoscope which can realistically be made finer using a shape memory alloy.

[0008]

In order to achieve the above-mentioned object, the bending portion of the endoscope of the present invention is provided at the outer periphery of the bending portion provided flexibly at the distal end portion of the insertion portion of the endoscope. A coil made of a shape memory alloy whose shape changes according to a predetermined temperature change is spirally wound, and the temperature of the coil is controlled in order to cause the coil to undergo a shape change that changes the bending state of the bending portion. A coil temperature control means is provided.

It is preferable that the curved portion is formed of an elastic tubular member having an internal component inserted therein, and the entire outer surface of the curved portion around which the coil is wound is
It may be covered with an elastic covering member.

[0010]

Embodiments will be described with reference to the drawings. The left half of FIG. 1 shows a side cross-section of the bending portion 1 provided at the distal end portion of the insertion portion of the endoscope formed by the flexible tube, and the right half is the outside of the proximal end side of the insertion portion. The coil temperature control circuit unit 20 provided is shown by a block. FIG. 2 is a front sectional view of the bending portion 1.

The curved portion 1 is formed of a highly elastic tubular member 2 made of, for example, silicone rubber or polyurethane rubber, and has an outer diameter of 2 mm and a length of 3, for example.
It is 0 mm.

As shown in FIG. 2, the tubular member 2 is formed with a plurality of holes for inserting internal components and the like in parallel with the tube axis. That is, an image guide fiber bundle 3 for transmitting an observation image, a light guide fiber bundle 4 for illuminating an observation range, and an electric wire 5 for bending operation described later are inserted, for example, a diameter of 0.35.
A forceps channel 9 for inserting a treatment tool such as forceps is formed in the upper half portion with three thin holes 6, 7 and 8 of about mm.
A thick hole having a diameter of 1.2 mm, for example, is formed in the lower half part.

The image guide fiber bundle 3
An objective optical system for forming an image of a subject on the image entrance end face of the image guide fiber bundle 3 is arranged at the tip end of the, but its illustration is omitted.

A coil 10 made of a shape memory alloy is wound around the outer circumference of the tubular member 2. The coil 10 has a circular cross-section with a wire diameter of, for example, 0.1 mm, and has a winding diameter of 2 mm and a length of 30 mm, for example, a spiral shape with a pitch of 0.3 mm, so that the coil 10 is in close contact with the outer circumference of the curved portion 1. Is wrapped around.

As the shape memory alloy, a shape memory alloy such as Ti-Ni type or Cu type can be used, and a predetermined bending shape of the bending portion 1 is stored in advance by heat treatment. Then, for example, when the temperature becomes 40 to 50 degrees Celsius or more, as shown in FIG. 3, the bending portion 1 has a radius of curvature of 25 m, for example.
It is set such that when the temperature is lowered by bending m, the restoring force of the tubular member 2 causes a linear state as shown in FIG.

Both ends of the coil 10 are drawn into a hole 8 through which the electric wire 5 is passed and are connected to the electric wire 5 in the hole 8. The tip opening of the hole 8 is sealed with a sealant 11 using an adhesive or the like.

Further, the entire outer surface of the curved portion 1 around which the coil 10 is wound is covered with an elastic and electrically insulating covering member 12 such as silicon rubber, for example, by a dipping method. To a thickness of 0.2 mm. The covering member 12 plays a role of electrical insulation and heat insulation.

The electric wire 5 is connected to the driver 21 in the coil temperature control circuit section 20 and is supplied with a current of, for example, 1.5 amperes. However, the pulse generator 22 is connected to the driver 21, and the driver 21 outputs a current having the same pulse waveform as the pulse signal input from the pulse generator 22.

The pulse generator 22 is connected to a pulse width setting device 23 capable of arbitrarily setting the pulse width, and by setting the pulse width given from the pulse generator 22 to the driver 21. , Driver 21
The duty ratio of the current output from the electric wire to the electric wire 5 can be freely changed.

The output current from the driver 21 is applied to the coil 10 via the electric wire 5, and the coil 10 made of a shape memory alloy generates heat by Joule heat. Then, due to the temperature of the coil 10 rising due to this, the coil 10
Bends in a direction approaching the stored bending shape, and the duty ratio of the drive current is changed.
The bending angle of can be changed freely.

The present invention is not limited to the above-described embodiment. For example, the temperature control of the coil 10 is performed by using fluid instead of using Joule heat by energizing the coil 10.
Heat may be applied to the air, or natural cooling may be used.

[0022]

According to the present invention, one coil made of a shape memory alloy is spirally wound around the outer circumference of the bending portion, and the bending portion is bent by the deformation of the coil which changes in response to the temperature change. As a result, the microfabrication of the shape memory alloy component is easy, and it is practically possible to reduce the diameter of the curved portion.

Further, by forming the inner curved portion of the coil by the tubular member having elasticity, the structure of the curved portion becomes very simple, and it becomes easy to reduce the diameter of the curved portion.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment.

FIG. 2 is a front sectional view of an example.

FIG. 3 is a side sectional view of the example in a bent state.

[Explanation of symbols]

1 curved part 2 tubular members 10 coils 20 Coil temperature control circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) A61B 1/00-1/32

Claims (3)

(57) [Claims] 1. A coil made of a shape memory alloy, the shape of which is changed by a predetermined temperature change, is spirally wound around the outer periphery of a bending portion provided at a distal end portion of an insertion portion of an endoscope so as to be bendable. The bending portion of the endoscope, further comprising coil temperature control means for controlling the temperature of the coil in order to cause the coil to undergo a shape change that changes a bending state of the bending portion. 2. The curved portion is formed by a flexible tubular member having an internal component inserted therein.
Curved part of the described endoscope. 3. The bending portion for an endoscope according to claim 1, wherein the entire outer surface of the bending portion around which the coil is wound is covered with an elastic covering member.