JP2002250272A - Oscillating structure body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart a new constitution for improving a heat radiation property to an actuator using a shape memory member. SOLUTION: The actuator 100 (the other one 101) having the shape memory member 1 (the other one 11) as a driving source is provided along a longitudinal direction of a lengthy substance A having oscillating parts A2-A3. The oscillating parts carry out an oscillating action by an action of the shape memory member. One or more heat conductive wire materials 4 are provided along the shape memory member and is extended to an area other than an area where the shape memory member 1 exists to cool the shape memory member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of micromachines applied to catheters and the like, and more particularly, to the structure of an actuator for swinging motion using a thin and long shape memory member as a driving source. It is about.

[0002]

2. Description of the Related Art Ultra-fine and long instruments such as endoscopes and multifunctional catheters to be inserted into blood vessels, etc., which reach a deep part of a test object and work at the tip thereof, include:
A small actuator for performing various swinging operations, such as bending and twisting, is mounted on the distal end portion by an operation on the hand side. Such an actuator is configured to be elongated so that it can be disposed in the ultra-fine elongated instrument. A typical configuration thereof uses a restoring force of a shape memory member such as a shape memory alloy coil as a drive source. Is mentioned.

[0003] Among the configurations using a shape memory member, for example, as disclosed in Japanese Patent Application Laid-Open No. 10-216238, the distal end portion of an instrument is pulled with a thread-like material by utilizing the expansion and contraction operation of the shape memory member. The configuration to bend by
It is possible to reduce the diameter of the entire mechanism of the actuator without impairing the flexibility of the device.

[0004]

In the above actuator, a shape memory member (particularly, a shape memory alloy coil) is used.
And a bias coil are combined so as to oppose each other, and repetitive reciprocating operation is enabled by heating / non-heating the shape memory member. In other words, when the shape memory member is heated, the restoring force due to the shape memory effect breaks the antagonism with the bias coil, and a restoring operation in a certain direction is performed. Lose
This is an operation in which the restoring force of the bias coil that has been deformed overcomes and returns to the original position.

On the other hand, in order to reduce the diameter of instruments such as endoscopes and catheters, it is required to make the actuator as thin as possible. In order to meet such a demand, the present inventor examined further reduction in the diameter of the actuator, and found that the following problem existed.

The problem is that when the diameter of the actuator is reduced, the space for the main mechanism for operation is prioritized and a sufficient cooling mechanism cannot be mounted. Therefore, when the heating is stopped to lower the temperature. There is a problem that the cooling method is simply natural heat radiation and heat is easily stored inside the mechanism of the actuator. If the heat easily accumulates inside the actuator mechanism, the temperature will not drop immediately even if the heating is stopped, and the operation time (the time required for one cycle in repeated operation) will be limited by the cooling time, and the operation will be repeated more than a certain amount of time. Cannot be achieved.

An object of the present invention is to solve the above-mentioned problems and to provide a new structure for improving heat radiation to an actuator using a shape memory member.

[0008]

SUMMARY OF THE INVENTION The present invention has the following features. (1) An actuator having a shape memory member as a drive source is provided along a longitudinal direction of a long object having a swingable portion, and the swingable portion performs a swing operation by an operation of the shape memory member. Is configured to do
One or more heat conducting wires are provided along the shape memory member,
A swing structure, wherein the heat conducting wire extends along a long object to a region other than a region where the shape memory member exists.

(2) The swingable portion is located near the tip of the long object, the actuator is adjacent to the swingable portion, and the heat conducting wire is closer than the actuator. The swing structure according to the above (1), wherein the swing structure extends to the region on the side of the part, to the hand of the long object, or to the outside via the hand of the long object.

(3) The heat conducting wire is 0.05 mm in diameter.
The swing structure according to the above (1), wherein the swing structure is a metal wire of about 1.0 mm.

(4) The actuator is configured such that the shape memory alloy coil spring and the bias coil spring are connected so as to oppose each other, and are capable of performing expansion and contraction operations in accordance with heating / non-heating of the shape memory alloy coil spring. The actuator is attached to the elongated object directly or via a pulling wire so as to connect both ends of the swingable portion, and the swingable portion is moved by the expansion and contraction operation of the actuator. The swing structure according to the above (1), wherein the swing structure is configured to perform the following.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a swing structure according to the present invention has an actuator (100,
101) is provided. The long object A is a tubular (or linear) member having a function to be described later such as a catheter or an endoscope, and one section thereof can be bent (or twisted) to be swung (or twisted) ( A2 to A3). Hereinafter, the swingable portion will be referred to as a “swinging portion” and described.

The actuator has the shape memory member 1 as a drive source, and is attached to the long object A so that the swing operation is performed at the swing portion.
The shape memory member 1 is heated by a heating unit (not shown), and performs a return operation (shrinkage or extension) to the original shape to bring a desired deformation to the swing part.

The present invention is characterized in that one or more heat conducting wires 4 made of a material having thermal conductivity are provided along the shape memory member 1 in addition to the mechanism for the swing operation described above. . In the drawing, the heat conducting wire is represented by a two-dot chain line to distinguish it from other drawing lines. The heat conducting wire 4
From the section where the shape memory member 1 is present, to other sections, particularly to an appropriate part on the hand side, and further to the outside of the instrument,
It is installed so as to extend along the long object A.

With this configuration, the heat conducting wire absorbs heat from the heated shape memory member, conducts the heat to the external region, and radiates heat there. As a result, the shape memory member is quickly cooled from the time when the heating is stopped, so that a quick repetitive operation is possible. In addition, by using a configuration in which thin and flexible forms of wires are used as a group, even if only a fine space is left in the device, and even if the space fluctuates along the longitudinal direction, the wire is used. Can be bundled and dispersed, the path can be distorted, and can be passed through the inside of the pipe while freely corresponding to the space of each part. Moreover,
Since it is possible to have a configuration in which small diameter wires do not restrain each other, the force required to bend the entire wire is only the sum of the bending forces of the individual fine wires, which may impair the flexibility required for the device. Absent.

The material of the heat conducting wire may be any material having heat conductivity sufficient to achieve the object of the present invention, and a metal is preferred. Above all, those having high thermal conductivity are preferable.
g, Cu, Au and the like.

The shape of the heat conducting wire is determined by the inner diameter of the pipe of the device,
Although it depends on the structure of the swinging structure, a diameter of about 50 μm to 300 μm is useful when the above metal material is used.

Although the number of heat conducting wires is not limited, it is preferable to provide as many as possible as long as the space permits, until the purpose of increasing the heat conductivity is achieved. However, it is preferable that the flexibility is not reduced, and
If there is an equilibrium state in which the heat dissipation does not improve even if the number is further increased, it is preferable to be within the range. For example, as shown in FIG. 2, in an endoscope apparatus in which various mechanisms are housed in an outer tube having an outer diameter of about 3 mm, a tubular long object A for fulfilling the original function of the endoscope.
When the outer diameter of the fiber (lumen, working channel, etc.) is set to about 1 mm, and a pair of actuators 100 are provided in a gap between the outer diameter and the outer tube, a diameter of 0.1 μm to 0 .2μ
A configuration in which about 10 to 40 wires of about m are arranged. Within this range, it is possible to achieve a high degree of compatibility between the improvement in thermal conductivity and the maintenance of flexibility in the reduced diameter structure.

The heat conducting wire should be arranged so as to efficiently take heat from the shape memory member and conduct it to other regions, and to radiate heat efficiently and sufficiently. Therefore, of the heat conducting wire, the side along the shape memory member is preferably provided along the entire length of the shape memory member, and is arranged so as to sufficiently cover the entire length of the shape memory member. You may. Further, it is preferable that the other end of the heat conducting wire extends outward from the shape memory member at least to such a length that heat is quickly dissipated. In order to prevent heat from accumulating in the heat dissipation area due to repeated heating of the shape memory member, make the heat conduction wire large enough so that the heat capacity of the heat dissipation area is sufficiently large. Preferably. For example, when the swing part is near the distal end of the long object and the actuator is provided adjacent to the hand part side of the swing part, the heat conducting wire is placed near the long object. To the outside, and further to the outside through the hand of the long object.

When the heat conducting wire is provided along the shape memory member, it is preferable to install the heat conducting wire as close as possible to the shape memory member in terms of directly absorbing heat. In addition, in addition to the above, it is also provided at a position circumferentially separated from the shape memory member along the body surface of the long object, such as the center two of the six wires shown in FIG. ,
It is good also as a structure which removes the heat which remains in the whole site | part of an actuator.

In some heating methods for the shape memory member, the shape memory member itself may be energized. In such a case, an appropriate insulating measure such as providing an insulating coating for preventing a short circuit may be taken. I just need.

Although the heat conducting wire 4 in the example of FIG. 1 is provided so as to cover only the area of the shape memory member 1, in order to absorb heat from the entire actuator area, the wire is used for the bias coil spring 2. It may extend to an area or more. In the example of FIG. 2, the distal end of the heat conducting wire 4 is fixed to support portions A20 and A30, which will be described later, so that the arrangement state of the heat conducting wire is not disturbed even if the shape memory member expands and contracts.

As the heat conducting wire, not only a simple wire having a simple circular cross section, but also various embodiments may be used. In particular, the heat absorption / release efficiency is further improved by a mode in which the surface area of the wire is increased, such as a mode in which grooves or irregularities are provided on the surface of the wire, a mode in which the wire is meandered, and a mode in which an ultrafine wire is twisted.

The mechanism itself of the actuator relating to the swing operation may refer to a known configuration. By applying a heat conducting wire to any actuator for swing operation using a shape memory member, The swing structure of the present invention can be configured. Hereinafter, a configuration example of the swing structure will be briefly described. In the following example, the long object will be described as a tube having a built-in function of an endoscope, and the shape memory member will be described as an SMA coil spring.

In the example shown in FIG. 1, a pair of actuators (1
00, 101) are attached in a front-to-back relationship,
The head can be swung in the direction of the arrow. The drive source of the actuator (100, 101) is a swing part (A2
-A3), and the tip side of the swing part is pulled by the pulling wires (3, 13). The traction wire is an inclusion for traction but shall be included in the actuator.

In the driving portion of the actuator, the SMA coil spring 1 and the bias coil spring 2 are connected so as to oppose each other. By controlling each actuator and pulling the pulling wire, it is possible to perform a swing motion in which the actuator is bent from the center position to both sides. The heat conducting wire 4 is provided so as to extend from the section where the SMA coil springs (1, 11) are present to the hand side.

In the example of FIG. 1, the return operation of the SMA coil spring 1 to the original shape is [shrinkage]. However, the positions of the shape memory member and the bias spring are interchanged, and the return operation of the shape memory member 1 is [extension]. Alternatively, the pulling wire may be pulled. The details of the configuration are described in the above-mentioned JP-A-10-2162.
38 may be referred to.

Although the pulling wire is interposed in the example of FIG. 1, the other end of the swinging portion may be directly pulled by the bias coil spring itself. That is, in the configuration of FIG. 1, one end of the SMA coil spring is connected to the proximal side A1 of one end of the swing part (A2 to A3),
In this embodiment, a bias coil spring is connected to the other end of the SMA coil spring, and the other end of the bias coil spring is connected to the tip side A3 of the swing part.

In the example shown in FIG. 1, the number of actuators is two. However, in order to form a swinging structure capable of freely bending a long object in an arbitrary direction, the swinging structure is arranged at equal intervals around the body of the flexible tube. An embodiment in which three (ie, every 120 °) or more are provided in parallel is preferable.

In the example of FIG. 2, the swing part is a section between A2 and A3. 1, two actuators are provided, but one of the actuators 100 will be described as a representative. SMA coil spring 1 of the actuator
Is set to recover in the direction of being heated and contracted, and one end thereof is connected to a part A1 closer to the hand than the swing part. The other end of the SMA coil spring 1 and the other end A3 of the swing part are connected via a pull wire 3.

On the other hand, the bias coil spring 2 is a compression coil spring, and is attached along the swing parts (A2 to A3) so as to be compressed when the swing part is bent and to store a restoring force. In the embodiment shown in the figure, a support portion A2 for setting a compression spring at both ends A2 and A3 of the swing portion.
0 and A30 are provided so as to protrude, and a bias coil spring is set between them. Traction wire 3
Pass through the hole of the support portion A20, pass through the inside of the bias coil spring 2, and are connected to the support portion A30. When the SMA coil spring 1 of the actuator is heated and contracted, the pulling wire is pulled and the oscillating portion is bent toward the actuator 100. At this time, the biasing coil spring 2 is compressed between the support portions A20 and A30, and the return force is reduced. Is stored. As in the example of FIG. 1, the heat conducting wire 4 is provided so as to extend from the section where the SMA coil springs (1, 11) are present to the hand side.

Although the use and scale of the swing structure are not limited, the cooling effect of the present invention is most remarkable because, as described in the description of the prior art, insertion into a body such as a catheter or an endoscope is performed. This is a case where the present invention is used for a long micromachine such as a medical instrument for industrial use, an industrial micromanipulator, or the like, in which the outer diameter is required to be fine.

When the outer diameter of each coil of the SMA coil spring and the bias coil spring is used in the above-described long micromachine, it is sufficient that the coil has an extra fine value usable therefor. Specifically, a preferable value is 1 mm or less, which is a unique range required for the coil outer diameter in the field of micromachines. For example, in the application to a catheter, the specific coil outer diameter of the SMA coil spring and the bias coil spring is 0.15 mm to 0.6 mm.
It is about. In addition, the lower limit of the coil outer diameter is not limited, and may be reduced without limit as the processing technology of the single filamentary wire or the technology of processing the coil winding is improved.

A known shape memory alloy may be used for the SMA coil spring. For example, Ti-Ni alloy, Ti-Ni-Cu alloy, Ti-Ni-Fe alloy, Ni-Al alloy, Ag-Cd alloy, Au-Cd
Alloy, Cu-Al-Ni alloy, Cu-Au-Zn alloy, Cu-Sn alloy, Cu-Zn alloy, Cu-Z
n-Al-based alloys, In-Ti-based alloys, In-Cd-based alloys, and the like.

As a heating method for causing the shape memory member to exhibit the shape memory effect, for example, a method of irradiating a laser beam through an optical fiber, a method of arranging a heater wire, and a method of heating the shape memory member itself There is a method of generating heat by supplying electricity.

The swing operation is an operation of displacing or twisting and returning at least to the original position. The bias force may be a bias force due to the elasticity of the long object itself, or a return spring may be used as in the examples of FIGS. Further, a shape memory member may be used as a return drive source, and may be opposed to the drive shape memory member. The oscillating part may be either a mode in which the entire section has flexibility and elasticity, or a type in which one place in a rigid body can be displaced like a universal joint.

When a plurality of actuators and the like are mounted around the body of a long object, as shown in a specific example in FIG. 3, node rings R1, R2, and R3 capable of maintaining the positional relationship of each coil spring in the body circumferential direction are used. Alternatively, a mode may be adopted in which the coil springs do not shift in the direction around the body of the long object. The node ring may be integral with the long object, or may be a separate part.
As an example of the structure of the node ring, one having a hole for inserting a long object at the center thereof and a hole for inserting a coil spring around the hole may be mentioned.

[0038]

EXAMPLES The present invention will be specifically described below with reference to examples. In this embodiment, the swing structure of the embodiment described with reference to FIG. 2 was actually manufactured, and as a comparative example for examining the operation and effect, a product in which the heat conducting wire was removed from the product of this embodiment was manufactured. did. These examples and comparative examples were actually operated, and the difference in the temperature drop of the SMA coil spring depending on the presence or absence of the heat conducting wire was examined.

The specifications of each part of the embodiment product are as follows. Long object A: The central body of the fiberscope serving as an endoscope, the outer diameter of which is 3 mm. In addition, the support parts A1
The distance between A2 is 30 mm. SMA coil spring 10: Material Ni-Ti alloy, wire diameter 0.1 mm, coil outer diameter 0.3 mm. Natural length 16mm,
The length when set is 20 mm, and the length when contracted to the stored original shape is 19 mm. Heating means: a configuration in which an optical fiber is inserted from the hand operation unit to the SMA coil spring, and the coil is irradiated with a laser beam having a wavelength of 0.82 μm to heat it. Bias coil spring 20: Material Ni-Ti alloy, wire diameter 0.15 mm, coil outer diameter 0.6 mm. Wire for heat conduction: Material Ag, wire diameter 0.1 mm, total number 28 arranged. As shown in the cross section of the device in FIG. 4, a large number of the heat conducting wires 4 were arranged not only in the vicinity of the SMA coil spring but also in an empty space, and extended 200 mm from the proximal end A1 of the SMA coil spring. The entire configuration described above was housed in an outer tube (0.1 mm in wall thickness, 2.8 mm in inner diameter) to obtain an endoscope device. The material of the outer tube was sus for the experiment for confirming the temperature characteristics. In addition, the appearances of the support portion and the node ring are as shown in FIG.

Temperature rise of the SMA coil spring due to heating,
The surface temperature of the outer tube covering the SMA coil spring was measured by a radiation thermometer to determine how the temperature dropped from when the heating was stopped. In the measurement, irradiation was performed for 60 seconds from the start of laser beam irradiation. After the irradiation was stopped, the surface temperature of the outer tube covering the vicinity of the middle point of the SMA coil spring was measured until the temperature almost dropped to room temperature. The relationship between the passage of time and the surface temperature of the outer tube is shown in the graph of FIG.
In the same graph, those plotted by black circles represent the temperature change of the product of the present example, and those plotted by white squares represent the temperature change of the product of the comparative example.

As is clear from the graph, in the same 60 seconds of laser light irradiation, the product of this example has a lower maximum temperature. This is due to the cooling effect of the heat conducting wire. Therefore, in the state of this graph, it is difficult to directly compare the degree of the temperature drop between the two. Therefore, attention was paid to a specific temperature common to both, and the time required for the temperature to fall from that temperature to a certain temperature was compared.

The specific temperatures common to both were 58.degree. C. and 45.degree. C., which are the highest attainable temperatures of the product of this embodiment. In the comparative example, the temperature was 58 ° C. 3 seconds after the irradiation was stopped, and the temperature drop time from that point is observed. The results of these comparisons are shown in Tables 1 and 2 below. In Table 1, 58 ° C. was set as a start temperature, and in Table 2, 45 ° C. was set as a start temperature.
From this, the time required to lower the temperature to 45 ° C., 40 ° C., 35 ° C., 30 ° C., and 25 ° C. respectively appears.

[0043]

[Table 1]

[0044]

[Table 2]

In the comparison of Table 1, the required descent time of the product of this example is 14% of the required descent time of the comparative product (from 58 ° C. to 45%).
(° C.) to 77% (58 ° C. → 25 ° C.), and this example shows a very quick cooling effect immediately after the irradiation is stopped. Also in the comparison of Table 2, the required descent time of the product of this example is 33% (45%) of the required descent time of the product of the comparative example.
° C → 40 ° C) to 77% (from 45 ° C to 25 ° C). From these comparisons, it is considered that the time required for temperature drop when the heat conducting wire is arranged is generally reduced by 20% to 30% or more as compared with the case where the heat conducting wire is not arranged.

[0046]

As described above, the structure provided with the heat conducting wire allows the shape memory member to be quickly cooled while reducing the diameter of the device, thereby shortening the time until the next heating. This enabled quick repetition of the swing motion.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a configuration example of a swing structure according to the present invention. A large number of wires 4 are arranged.
Reference numeral 4 is attached to the book as a representative.

FIG. 2 is a schematic view showing another configuration example of the swing structure according to the present invention.

FIG. 3 is a view showing a specific appearance of the swinging structure of FIG. 2;

FIG. 4 is a view showing a cross-section XX of the swing structure of FIG. 3;

FIG. 5 is a graph showing the results of measuring the temperature drop state of the example product and the comparative example product.

[Explanation of symbols]

 A Long object 1 Shape memory member (SMA coil spring) 2 Coil spring for bias 3 Thread 4 Material for heat conduction

Claims (4)

[Claims] An actuator having a shape memory member as a drive source is provided along a longitudinal direction of a long object having a swingable portion, and the swingable portion is swung by the operation of the shape memory member. And one or more heat conducting wires are provided along the shape memory member,
A swing structure, wherein the heat conducting wire extends along a long object to a region other than a region where the shape memory member exists. 2. The swingable portion is located near the tip of the long object, the actuator is adjacent to the swingable portion, and the heat conducting wire is closer to the hand than the actuator. The swing structure according to claim 1, wherein the swing structure extends to a side region, to a hand portion of the long object, or to the outside through a hand portion of the long object. 3. The heat conducting wire has a diameter of 0.05 mm or more.
The swing structure according to claim 1, wherein the swing structure is a 1.0 mm metal wire. 4. An actuator, wherein a shape memory alloy coil spring and a bias coil spring are connected so as to oppose each other, and are configured to be able to expand and contract in accordance with heating / non-heating of the shape memory alloy coil spring. The actuator is attached to an elongated object directly or via a pulling wire so as to connect both ends of the swingable portion, and the swingable portion performs the swing operation by the expansion and contraction operation of the actuator. The swing structure according to claim 1, wherein the swing structure is configured to perform the swing operation.