JP3086017B2 - Flexible tube device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular insert for medical treatment inserted into a body cavity such as a catheter, a medical endoscope, a laser probe, or the like, or a gas pipe, a water pipe, or a plant pipe. The present invention relates to a flexible tube device that is operated to bend, such as a borescope that is inserted into the device.

[0002]

2. Description of the Related Art Generally, an endoscope includes an operation section and an insertion section connected to the operation section. Further, the insertion portion includes a flexible tube portion, a curved tube portion provided at the distal end thereof, and a distal end component portion provided at the distal end of the curved tube portion. The bending tube section is formed by connecting a large number of tubular bodies rotatably in up, down, left, and right directions, and can be bent by the operation section.

As a structure for bending a bending tube, a structure disclosed in Japanese Patent Application Laid-Open No. 62-26041 is conventionally known. Hereinafter, this conventional example will be described with reference to the drawings.

[0004] As shown in FIG.
The flexible tube 200 is provided with a plurality of bending operation mechanisms. The bending operation mechanism includes a shape memory alloy (SM) having one end fixed to a fixing portion 206 provided in the distal end portion of the flexible portion 202.
A) A wire 203 and a bending wire 204 having one end fixed to a fixing portion 205 provided at the tip of the bending tube portion 201 are provided. The other ends of these wires 203 and 204 are connected to each other.

[0005] Such a flexible tube 200 expands and contracts the SMA wire 203 by energizing and overheating to obtain a flexible tube 200 as shown in FIG.
As shown in FIG. 2B, the bending tube portion 201 can be bent via the bending wire 204.

The shape of the SMA wire 36 is preferably a stranded wire rather than a single wire. This is because the knitting of the single wire having a large surface area into a stranded wire improves the flexibility and cooling effect of the SMA wire 36.

[0007]

As a method of controlling the amount of bending of the flexible tube, it has been considered to measure the electric resistance of the SMA and perform feedback control.

[0008] However, when a stranded SMA wire is used, not only the electric resistance value of the SMA wire itself changes due to heating, but also each SM forming the stranded wire by a deformation operation.
Since the contact resistance between the A wires changes, the control based on the electric resistance value cannot perform sufficient control. Therefore, the object of the present invention is to use a stranded wire shape memory alloy,
An object of the present invention is to provide a flexible tube device capable of performing accurate bending control.

[0009]

According to a first aspect of the present invention, there is provided a flexible tube device, wherein a stranded wire-shaped shape memory alloy is provided at a tip end of the flexible tube device. A flexible tube device having a flexible tube curved by:
Control means for heating and deforming the shape memory alloy while controlling the amount of heating; and resistance due to phase transformation of the shape memory alloy.
Of the contact resistance between the wires constituting the stranded wire
A combined resistance value detecting means for detecting a combined resistance value obtained by combining the change and the change, and based on a relationship between the combined resistance value and the deformation amount of the shape memory alloy, the detected combined resistance value depending characterized in that and a switching means for switching a control parameter of the control means.

A flexible tube device according to a second aspect of the present invention has a flexible tube which is provided with a stranded wire-shaped shape memory alloy at a distal end thereof and which is bent by expansion and contraction deformation of the shape memory alloy. Control means for heating and deforming the shape memory alloy while controlling the amount of heating, and a phase change of the shape memory alloy.
Of the resistance value due to the condition and between the wires constituting the stranded wire
Detects the combined resistance value that is combined with the change in contact resistance
A combined resistance value detecting means, based on the relationship between the control parameters of the combined resistance value <br/> and the control means of the shape memory alloy,
Depending on the detected combined resistance value, characterized in that and a switching means for switching a control parameter of the control means.

[0011]

According to the above construction, the phase transformation of the shape memory alloy can be performed.
And the connection between the wires making up the stranded wire
Even if the combined resistance value that is combined with the change in tactile resistance changes ,
Relationship between the combined resistance value and the amount of deformation of the shape memory alloy, one Rui based on the relationship between the combined resistance value <br/> control parameter and the shape memory alloy of the control means, the heating in response to changes in combined resistance value Because control is done. Optimal heating control can be performed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 8 show an embodiment in which the present invention is applied to an industrial endoscope as a first embodiment of the present invention.

As shown in FIG. 1, an industrial endoscope 1 has a long flexible tube 2, a bending portion 4 provided at the distal end thereof, and a plurality of bending tubes (not shown). A rigid portion 6 is provided at the tip of the curved portion 4 and has an optical system (not shown). The flexible tube 2 is wound around a rotatable drum 8.

A universal cord 10 connected to the flexible tube 2 extends from the drum 8, and the universal cord 10 is connected to the video processor 1 via a connector 12.
4, the light source device 16, and the bending control device 18 are connected.

The video processor 14 displays an image captured by the industrial endoscope 1 on a display monitor 20. The bending control device 18 controls the bending operation of the bending section 4 via the bending operation device 22. As shown in FIG. 2, the curved portion 4, bending mechanism portion 3 7 for bending, for example, in the vertical direction, 41
Can be bent. Further, the inner wall 30 of the bending portion 4 is connected to a flexible tube base 33 provided at a distal end portion of the flexible tube 2 via a ring-shaped connecting member 42.

[0016] In the bending mechanism portion 3 7, 41, with respect to the fixed member 31 fixed to the distal end of the bending portion 4, the wire 32 is brazing fixed. The wire 32 is connected to a shape memory alloy (hereinafter abbreviated as SMA) wire 36 via a wire connecting member 34. This SMA wire 36
It is in the form of a stranded wire as described later.

Further, the SMA wire 36 and the wire 32
Is inserted through an incompressible member 38, for example, a coil sheath, and the coil sheath 38 and the SMA wire 36
Is fixed to the plug 40. This plug 40
Is a free end in the longitudinal direction with respect to a longitudinal stress due to the bending of the flexible tube 2. The distal end side of the coil sheath 38 is brazed to the connecting member 42.

Incidentally, the total length of the wire 32 and the SMA wire 36 is adjusted so that the bending mechanism section 3 prevents the wire on the other side from being excessively stretched when the bending section 4 is bent to one side.
7 and 41 are slightly longer and loosened. Also,
An insulating tube 44 having heat resistance is fitted inside the coil sheath 38 in order to maintain insulation between the coil sheath 38 and the SMA wire 36.

As shown in FIG. 3, the wire connecting member 34
Is formed by attaching metal members 48 on both sides of an insulating member 46 in the extending direction of the wires 32 and 36. The wire 32 is fixed to one of the metal members 48, and the SMA wire 36 and the lead wire 50 are electrically connected and fixed to the other. Note that the lead wire 50 is covered with an insulating tube except for a connection portion with the metal member 46.

As shown in FIG. 4A, the plug 40
An inner layer 35 made of an outer layer 3 9 and the metal member made of an insulating member
Consists of One end of the inner layer 35 has an SMA wire 36
Is fixed, and a lead wire 52 is electrically connected and fixed to the other end.

As shown in FIG. 4B, the plug 40 is provided with a lead wire insertion hole 60 and a plurality of ventilation holes 62. The lead wire 50 is inserted into the lead wire insertion hole 60.
(See FIG. 4 (a)).

Referring again to FIG. 4A, the plug 40
, A coil sheath 38 is connected to one end, and one end of an air tube 54 is connected to the other end. A connector 56 is connected to the other end of the air tube 54.
The lead wire 5 is inserted through a side hole 58 provided in the connector 56.
0, 52 can be pulled out of the air tube 54. Further, this connector 56 can be connected to an electromagnetic valve described later. Note that a seal (not shown) is provided in the side hole 58 to maintain airtightness.

As shown in FIG. 5, the bending control device 18
Energization control circuit 6 for controlling energization heating of SMA wire 36
4 and four solenoid valves 68 to which the connector 56 is connected.
And an electromagnetic valve control circuit 6 for controlling the opening and closing of the electromagnetic valve 68.
6 is provided.

The solenoid valve 68 is connected to a compressor 70 for supplying cooling air through a fluid line (not shown). Then, the electromagnetic valve control circuit 66 controls the opening and closing of the electromagnetic valve 68, so that the cooling of the SMA wire 36 can be controlled.

The energization control circuit 64 energizes and heats the SMA wire 36 and controls the energization by, for example, a pulse width modulation (PWM) method. Further, the energization control circuit 6
No. 4 improves the control accuracy by constantly detecting and feeding back the resistance value of the SMA wire 36.

Energization control circuit 64 and solenoid valve control circuit 66
Can be easily operated and controlled by operating means (not shown) such as a joystick of the bending operation device 22 connected to the bending control device 18.

As shown in FIG. 6, the SMA wire 36
In order to improve the cooling effect by the solenoid valve control circuit 66 and to improve the flexibility, a single wire having a large surface area is assembled in a stranded form. The configuration of the energization control circuit 64 is shown in detail in FIG.

The signal input from the operation unit 22 to the power supply control circuit 64 is input to the PWM circuit 72 through the PID controller 71. In the PWM circuit 72, a PWM signal is generated, and a ratio between a conduction period and a non-conduction period is determined.
This PWM signal is supplied to the SMA wire 3 through the driver 73.
6 is applied. Thereby, the SMA wire 36 performs a bending operation.

The bridge circuit 76 is connected to the SMA wire 3
6 is detected, and the non-energized value is sampled by a sample / hold (S / H) 75. The sampled value is fed back to the PID controller 71 and is input to the parameter switch 74. The parameter switch 74 inputs a parameter corresponding to the input electric resistance value to the PID controller 71. Switching of this parameter is performed by the SMA shown in FIG.
The processing is performed based on the relationship between the electric resistance value of the wire 36 and the bending angle. While the resistance of a general metal increases with an increase in temperature, the resistance of SMA decreases with an increase in temperature during phase transformation.

In FIG. 8, sections AC and GH are changes due to the phase transformation of the SMA wire 36. Sections CD and FG are changes in resistance due to phase transformation of the SMA wire 36 and changes in contact resistance of each wire constituting the stranded wire 36. When the SMA wire 36 is heated, it shrinks in the axial direction, and each SM forming a stranded wire shape
It is considered that the contact resistance of the A wire decreases. Further, the section DF has characteristics similar to those of a general metal. That is, the phase transformation is completed.

According to such a relationship, it is possible to determine which section the current state corresponds to by detecting the resistance value. Therefore, the parameters of the PID controller 71 are switched according to the detected resistance value. For example, when the resistance value R of the SMA is in the range of R ₂ <R <R ₃ , the parameter P is increased to improve the responsiveness because the bending angle does not change much with the change in the resistance value. Also, R ₁ <R
<In the range of R _2, the response of a good, in order to facilitate the fine adjustment of the bending angle, increasing the parameter I.

The operation of the endoscope 1 as described above will be described. Now, when the energization heating of the energization control circuit 64 causes the SMA
It is assumed that the wire 36 is contracted. In this case, since the bending mechanisms 3 7 and 41 are constituted by the incompressible coil sheath 38 in the longitudinal direction, the incompressible coil sheath 3 is used.
In the portion 8, the entire length does not change, and all the tension due to the contraction of the SMA wire 36 is applied to the bending portion 4. Therefore, the bending portion 4 can be bent. When the electromagnetic valve 68 is opened by the electromagnetic valve control circuit 66 and the cooling air from the compressor 70 is supplied to the SMA wire 36, the SMA wire 36 can be cooled and expanded. Furthermore, S
The PID controller 71 according to the range of the MA resistance value
By switching the parameters described above, good control can be performed over the entire range.

[0033] In this example, shows only bending mechanism 3 7, 41 for upward and downward bending mechanism, in practice, the endoscope 1 is provided with a similar bending mechanism also left-right direction. The bending mechanisms in each direction can be operated independently of each other. FIG. 9 shows an embodiment in which the present invention is applied to a catheter as a second embodiment of the present invention.

The catheter 80 has a curved portion 81 at the distal end and an insertion portion 82. These bending portion 81 and insertion portion 8
2 is formed of a flexible multi-lumen tube having different hardnesses. The tube forming the curved portion 81 and the tube forming the insertion portion 82 are a heat-shrinkable tube 90
Are connected to each other by being inserted through.

A channel 86 and a wire insertion hole 87 pass through the curved portion 81 in the axial direction. The channel 86 is for inserting a small-diameter scope, a guide wire, or the like.

On the other hand, in the wire insertion hole 87, a stranded SMA wire 8 having both ends fixed by metal members 83 and 84 is formed.
5 is inserted. The distal end surface of the wire insertion hole 87 is sealed by a cap 89 made of thermosetting resin. Further, each of the metal members 83 and 84 is connected to a conduction control circuit through a lead wire 88. The SMA wire 85 is energized and heated by the energization control circuit 64 (FIG. 7). Here, the energization control circuit 64 is the same as in the first embodiment, and a description thereof will be omitted.

FIG. 10 shows the relationship between the current value I flowing through the SMA wire 85 and the resistance value R of the SMA wire 85.
Points A to H in the figure correspond to points A to H in FIG. 8 of the first embodiment.

In the present embodiment, the relationship between the current value and the resistance value is classified into regions I to IV, and the parameters of the PID controller 71 are changed according to each region in the same manner as in the first embodiment.

Here, which region the current state corresponds to can be easily determined from the current value and the resistance value. However, since the SMA includes a delay element, the boundaries between the regions are strictly unclear. Therefore, it is useful to apply fuzzy inference to determine each region. That is,
If each area is determined by fuzzy inference in consideration of the SMA delay element, more accurate parameter setting is possible.

In FIG. 9, if the heat-shrinkable tube 90 or the cap 89 is damaged such as crack, tear, peeling, etc.
Early detection of this breakage is important because the SMA wire 85 is exposed and there is a risk of burns and electric shock. Therefore, for example, the color of the tube 90 may be different from the color of the metal members 83 and 84 and the SMA wire 85 and the like inside. In this case, when the tube 90 is damaged, the metal members 83 and 84, the SMA wire 85, and the like are exposed from the damaged portion, so that the damaged portion can be easily found by visual inspection due to a difference in color from the tube 90. Alternatively, when the side peripheral surface of the SMA wire 85 is covered with a resin of a color different from that of the tube 90,
You can find the damaged part in the same way as above

Also, the color of the curved portion 81 and the cap 89,
Alternatively, when the color of the tip end surface of the SMA wire 85 and the color of the cap 89 are different from each other, the cap 8 is formed by comparing the colors.
9 can be easily found. For example, SMA wire 85
May be covered with a thermosetting resin of a color different from that of the cap 89.

FIG. 11 shows another example of the configuration of the above-mentioned current supply control circuit as a third embodiment of the present invention. In this embodiment, S
To cool the MA wire 36, a water-cooled or air-cooled cooling pump 92 controlled by a pump controller 93 is used. In the following description, portions different from the first embodiment will be mainly described.

The resistance value detection circuit 91 is connected to the SMA wire 36
The resistance value of is detected. The detected resistance value is fed back to the PID controller 71 and is input to the parameter switch 94. The parameter switch 94 switches parameters of the pump controller 93 according to the input detection resistance value. This parameter is switched in the section shown in FIG. 8, as in the first embodiment. Then, the cooling pump 92 is driven according to a parameter of the pump controller 93, and cools the SMA wire 36 with water or air. By switching the parameters of the cooling pump 92 in this manner, simple cooling control can be performed.

The energization control circuit according to the third embodiment comprises:
By switching the parameters according to the region shown in FIG. 10, the SMA wire 85 of the catheter 80 of the second embodiment is changed.
It can also be applied to cooling. Also,

In each of the above embodiments, the PID controller 71 is used as the controller of the power supply control circuit. However, a controller (such as an optimal regulator) to which fuzzy control or modern control theory is applied may be used. Also,
For switching control parameters, SMA wire 3
Although 6,85 resistance values have been detected, other physical values such as temperature may be detected.

[0046]

As described above, according to the flexible tube device of the present invention, although the stranded wire shape memory alloy is used.
Thus , accurate bending control of the flexible tube is realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of an industrial endoscope according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a distal end portion of the industrial endoscope of FIG.

FIG. 3 is an enlarged sectional view showing a configuration of a wire connecting member in FIG. 2 in an enlarged manner.

FIG. 4 is a view showing the plug in FIG. 2;
(A), (b) is shown, (a) is an enlarged sectional view showing a configuration of a plug, (b) is a sectional view taken along line AA 'of (a).

FIG. 5 is a block diagram for explaining the operation of a bending mechanism in FIG. 2;

FIG. 6 is an enlarged side view showing the shape memory alloy wire in FIG. 2 in an enlarged manner.

FIG. 7 is a block diagram illustrating a configuration of a conduction control circuit in FIG. 5;

FIG. 8 is a diagram showing a relationship between a bending angle and a resistance value of the shape memory alloy wire in FIG.

FIG. 9 is a configuration diagram showing a second embodiment of the present invention and showing a configuration of a main part of a catheter.

FIG. 10 is a diagram showing a relationship between a current value applied to the shape memory alloy wire in FIG. 9 and a resistance value of the shape memory alloy wire.

FIG. 11 is a block diagram illustrating a configuration of an energization control circuit according to a third embodiment of the present invention.

FIG. 12 is a diagram schematically showing a curved tube portion of a conventional flexible tube, including (a) and (b), where (a) is a configuration diagram showing a configuration of the curved tube portion, and (b). FIG. 4 is an explanatory diagram for explaining an operation of the bending tube portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Industrial endoscope, 2 ... Flexible tube, 36, 85 ... Stranded shape memory alloy wire, 64 ... Energization control circuit (control means), 74 ... Parameter switcher (switching means), 76 ... Bridge circuit (Detection means), 91 ... resistance value detection circuit (detection means).

Claims (2)

(57) [Claims] 1. A flexible tube device having a stranded wire-shaped shape memory alloy disposed at a tip end thereof and having a flexible tube bent by expansion and contraction deformation of the shape memory alloy, wherein a heating amount is controlled. Controlling means for heating and deforming the shape memory alloy; and changing the resistance value due to the phase transformation of the shape memory alloy and the twisting.
The change in contact resistance between the wires that make up the
A combined resistance value detecting means for detecting the combined resistance value, based on a relationship between deformation amount and the combined resistance value of the shape memory alloy, switches the control parameters of the control means in response to the detected combined resistance value flexible tube apparatus characterized by comprising a switching means. 2. A flexible tube device having a stranded wire-shaped shape memory alloy disposed at a tip end thereof and having a flexible tube bent by expansion and contraction deformation of the shape memory alloy, wherein a heating amount is controlled. Controlling means for heating and deforming the shape memory alloy; and changing the resistance value due to the phase transformation of the shape memory alloy and the twisting.
The change in contact resistance between the wires that make up the
A combined resistance value detecting means for detecting the combined resistance value, based on the relationship between the control parameters of the combined resistance value and the control means of the shape memory alloy, the detected combined resistance
Flexible tube apparatus characterized by comprising a, a switching means for switching a control parameter of the control means in response to the value.