WO2016185562A1

WO2016185562A1 - Variable-hardness actuator

Info

Publication number: WO2016185562A1
Application number: PCT/JP2015/064326
Authority: WO
Inventors: 哲矢森島
Original assignee: オリンパス株式会社
Priority date: 2015-05-19
Filing date: 2015-05-19
Publication date: 2016-11-24

Abstract

This variable-hardness actuator (10), which is mounted to a flexible member and makes it possible to impart different hardnesses to the flexible member, is provided with a shape memory member (20) that is capable of changing phases between a first phase and second phase, and a plurality of inductive members (30) that cause the shape memory member (20) to undergo a change in phase between the first phase and second phase. The shape memory member (20), when in the first phase, assumes a soft state in which said member can be easily deformed in accordance with an external force and consequently imparts relatively low hardness to the flexible member. The shape memory member (20), when in the second phase, assumes a hard state in which said member resists an external force and exhibits a tendency to assume a pre-stored memory shape, and consequently imparts relatively high hardness to the flexible member. One end (34) of each of the inductive members (30) is electrically connected to a common conductive member (20).

Description

Variable hardness actuator

The present invention relates to a hardness variable actuator for changing the hardness of a flexible member.

Japanese Patent No. 3212673 discloses an endoscope that can change the hardness of the soft part of the insertion part. In this endoscope, both ends of a flexible member (for example, a coil pipe) are fixed at predetermined positions of the endoscope, and a flexible adjustment member (for example, a coil pipe) is inserted into the flexible member. A flexible adjusting wire) is fixed via a separator. The flexible member and the flexibility adjusting member extend along the soft portion to the operation portion, and extend over substantially the entire soft portion. By pulling the flexibility adjusting member, the flexible member is compressed and hardened, thereby changing the hardness of the soft part.

Since the flexible member and the flexible adjustment member extend over almost the entire soft part, a very large force is required to drive such a mechanism. When this mechanism is electrified, a large power source is required, and the configuration becomes large.

Japanese Patent No. 3142828 discloses a hardness varying device for a flexible tube using a shape memory alloy. This hardness varying device is arranged to extend in the axial direction in a coil disposed in a flexible tube, an electrically insulating tube disposed inside the coil, and the electrically insulating tube. A shape memory alloy wire and an electric heating means for energizing the shape memory alloy wire are provided.

The shape memory alloy wire has the property that its length expands at low temperatures and contracts at high temperatures. The shape memory alloy wire extends through fixing portions provided at both ends of the coil, and a caulking member is fixed to both ends thereof. The shape memory alloy wire is arranged so that it is loosened at a low temperature and the caulking member is engaged with and stretched at a fixed part at a high temperature.

Shape wire made of shape memory alloy shrinks and hardens the coil at a high temperature heated by the electric heating means. On the other hand, at low temperatures without energization, the shape memory alloy wire stretches to soften the coil.

This hardness variable device can be configured in a small size because of its simple configuration, but when the shape memory alloy wire contracts, both ends of the shape memory alloy wire are constrained and a load is applied to the shape memory alloy wire. There is difficulty in its durability.

An object of the present invention is to provide a durable variable hardness actuator that is mounted on a flexible member and can provide different hardness to the flexible member with a simple configuration.

For this purpose, the hardness variable actuator includes a shape memory member in which the phase can change between the first phase and the second phase, and a phase change between the first phase and the second phase in the shape memory member. The induction member which causes is provided. When in the first phase, the shape memory member assumes a soft state that can be easily deformed according to external forces, thus providing a relatively low hardness for the flexible member. In addition, when the shape memory member is in the second phase, it takes a hard state showing a tendency to take a memory shape memorized in advance against an external force, and thus the flexible member has a relatively high hardness. provide. Both ends of the plurality of induction members are electrically connected to a common conductive member.

FIG. 1 shows a variable hardness actuator according to the first embodiment. FIG. 2 is a view for explaining the operation of the hardness variable actuator, and shows a state in which the hardness state of the shape memory member is changed according to switching of the switch of the drive circuit. FIG. 3 is a diagram for explaining the operation of the hardness variable actuator in a situation in which an external force is acting on the portion of the shape memory member near the lower end of the induction member in a direction perpendicular to the central axis of the shape memory member. FIG. 4 shows how the hardness state of the shape memory member is changed according to switching of the switch of the drive circuit. FIG. 4 is a view for explaining the operation of the hardness variable actuator. In the situation where an external force is applied to the shape memory member in a direction parallel to the central axis of the shape memory member, the switch of the drive circuit is switched. The mode that the hardness state of a shape memory member is changed is shown. FIG. 5 is a diagram for explaining the operation of the hardness variable actuator, and shows a state in which the presence or absence of an external force is switched in a situation where the switch of the drive circuit is in an OFF state and the shape memory member is in a soft state. . FIG. 6 is a diagram for explaining the operation of the hardness variable actuator, and shows a state in which the hardness state of the bent shape memory member is changed from the soft state to the hard state in accordance with switching of the switch of the drive circuit. . FIG. 7 is a diagram for explaining the operation of the hardness variable actuator, and shows a state in which the presence or absence of an external force is switched in a situation where the switch of the drive circuit is in an on state and the shape memory member is in a hard state. . FIG. 8 shows a hardness variable actuator according to the second embodiment. FIG. 9 is an enlarged view of a part of the hardness variable actuator shown in FIG. FIG. 10 shows a variable hardness actuator according to the third embodiment.

[First embodiment]
〔Constitution〕
FIG. 1 shows a variable hardness actuator according to the first embodiment. As shown in FIG. 1, the hardness variable actuator 10 has a function of providing the flexible member with different hardness by being able to take different hardness states, and between the first phase and the second phase. And a plurality of induction members 30 that cause the shape memory member 20 to cause phase transition between the first phase and the second phase. The shape memory member 20 is disposed on the flexible member with at least one free end.

When the shape memory member 20 is in the first phase, it takes a soft state that can be easily deformed according to an external force, that is, exhibits a low elastic modulus, and thus provides a relatively low hardness for the flexible member. Further, when the shape memory member 20 is in the second phase, the shape memory member 20 takes a hard state showing a tendency to take a memory shape memorized in advance against an external force, that is, exhibits a high elastic coefficient, and thus is flexible. Providing a relatively high hardness to the structural member. The memory shape is not limited to this, but may be a linear shape, for example.

Here, the external force means a force that can deform the shape memory member 20, and gravity is also considered as a part of the external force.

The induction member 30 has a performance of generating heat. The shape memory member 20 has a property that the phase is changed from the first phase to the second phase with respect to the heating of the induction member 30.

The shape memory member 20 is elongated, and the plurality of induction members 30 are arranged at intervals along the longitudinal axis of the shape memory member 20.

The plurality of induction members 30 may be the same structure as depicted in FIG. However, without being limited thereto, the plurality of induction members 30 may include a plurality of different structures. Different structures may have, for example, different lengths, different thicknesses, different pitches, and may be made of different materials. That is, all or some of the plurality of induction members 30 may have the same characteristics or different characteristics.

The shape memory member 20 may be made of, for example, a shape memory alloy. The shape memory alloy is not limited to this, but may be, for example, an alloy containing NiTi. The shape memory member 20 is not limited to this, and may be made of other materials such as a shape memory polymer, a shape memory gel, and a shape memory ceramic.

The shape memory alloy constituting the shape memory member 20 may be one in which the phase changes between the martensite phase and the austenite phase, for example. The shape memory alloy undergoes plastic deformation relatively easily with respect to external force during the martensite phase. That is, the shape memory alloy exhibits a low elastic modulus during the martensite phase. On the other hand, the shape memory alloy resists external force and does not easily deform during the austenite phase. Even if it is deformed due to a large external force, if the large external force disappears, it shows superelasticity and returns to the memorized shape. That is, the shape memory alloy exhibits a high elastic modulus during the austenite phase.

The induction member 30 may be composed of a heater, for example. That is, the inducing member 30 may have the property of generating heat in response to the supply of current flowing therethrough. The induction member 30 may be, for example, a heating wire, that is, a conductive member having a large electric resistance. Moreover, the induction member 30 should just have the capability to generate | occur | produce heat, and may be comprised not only with a heater but with an image pick-up element, a light guide, other elements, members, etc. Furthermore, the induction member 30 may be configured by a structure that generates heat in a chemical reaction.

The shape memory member 20 may be made of a conductive material. For example, an insulating film 42 is provided around the shape memory member 20. The insulating film 42 functions to prevent a short circuit between the shape memory member 20 and the induction member 30. The insulating film 42 is provided so as to cover at least a portion facing the induction member 30. Although FIG. 1 illustrates a form in which the outer peripheral surface of the shape memory member 20 is partially covered, the present invention is not limited thereto, and is provided so as to cover the entire outer peripheral surface of the shape memory member 20. Alternatively, the shape memory member 20 may be entirely covered.

The induction member 30 may be made of a conductive material. For example, an insulating film 44 is provided around the induction member 30. The insulating film 44 functions to prevent a short circuit between the shape memory member 20 and the induction member 30 and a short circuit between adjacent portions of the induction member 30.

The hardness variable actuator 10 includes an insulating member that prevents a short circuit between the shape memory member 20 and the induction member 30. The insulating film 42 and the insulating film 44 hit this insulating member. If the insulating film 44 provides a reliable short circuit prevention function, the insulating film 42 may be omitted.

The shape memory member 20 has a first end 22 and a second end 24, and each induction member 30 has a first end 32 located on the first end 22 side of the shape memory member 20, and The shape memory member 20 has a second end 34 located on the second end 24 side. The induction member 30 has conductivity, and the first end 32 of the induction member 30 is electrically connected to the control unit 50 via the wiring 64. The shape memory member 20 is also electrically conductive, and the second ends 34 of the respective induction members 30 are both electrically connected to the shape memory member 20 via the conducting member 66. The conductive member 66 may be constituted by, for example, wiring, but is not limited thereto, and may be a structure that can be electrically connected. For example, caulking, welding, brazing, soldering, conductive bonding You may be comprised with an agent etc. The shape memory member 20 is electrically connected to the control unit 50 via the wiring 62 on the first end 22 side.

The control unit 50 includes one power source 52 and a plurality of switches 54. One end of each of the plurality of switches 54 is connected to the wiring 64, and the other end thereof is commonly connected to a power source. A wiring 62 is connected to the power source 52. The controller 50 independently supplies a current to the corresponding induction member 30 in response to the on or closing operation of each switch 54, and the corresponding induction in response to the off or opening operation of each switch 54. The supply of current to the member 30 is stopped independently. The induction member 30 generates heat in response to the supply of current.

The shape memory member 20 may be a wire shape. The induction member 30 is disposed near the shape memory member 20. The induction member 30 may be coiled, and the shape memory member 20 may extend through the inside of the coiled induction member 30. Thanks to such an arrangement, the heat generated by the induction member 30 is efficiently transmitted to the shape memory member 20.

[Explanation of variable hardness actuator operation]
The operation of the above-described variable hardness actuator will be described below with reference to FIGS. For convenience, it is assumed that one end of the shape memory member 20 is fixed, and the operation of the peripheral portion of the induction member 30 near the fixed end will be described. Further, it is assumed that the memory shape of the shape memory member 20 is a linear shape. In FIGS. 2 to 7, the shape memory member 20 in the soft state is shown with a left-upward hatching, and the shape memory member 20 in a hard state is shown with a right-upward hatching.

FIG. 2 shows a state in which the hardness state of the shape memory member 20 is changed in accordance with switching of the switch 54 of the control unit 50.

On the left side of FIG. 2, the switch 54 of the control unit 50 is in an OFF state, that is, is open, and the shape memory member 20 is in a first phase in a soft state with a low elastic modulus.

As shown on the right side of FIG. 2, when the switch 54 of the control unit 50 is turned on, that is, closed, a current flows through the induction member 30 and the induction member 30 generates heat. As a result, the shape memory member 20 changes to the second phase that is in a hard state with a high elastic coefficient.

FIG. 3 shows that the external force F1 acts on the portion of the shape memory member 20 near the lower end of the induction member 30 in a direction perpendicular to the central axis of the shape memory member 20, and according to switching of the switch 54 of the control unit 50. The mode that the hardness state of the shape memory member 20 is changed is shown. The external force F1 is smaller than the restoring force that the shape memory member 20 tries to return to the memory shape.

3, the switch 54 of the control unit 50 is in the OFF state, and the shape memory member 20 is in the first phase in the soft state. In the first phase, the shape memory member 20 is easily deformed according to the external force F1. The shape memory member 20 is bent by the external force F1.

3, when the switch 54 of the control unit 50 is switched to the on state, the induction member 30 generates heat, and the shape memory member 20 changes to the second phase that is in the hard state. In this second phase, the shape memory member 20 tends to take a memory shape. That is, if the shape memory member 20 has a shape different from the memory shape, the shape memory member 20 attempts to return to the memory shape. Since the external force F1 is smaller than the restoring force of the shape memory member 20, the shape memory member 20 returns to the memory shape, that is, the linear shape against the external force F1.

FIG. 4 shows that the hardness state of the shape memory member 20 is changed according to the switching of the switch 54 of the control unit 50 in a situation where the external force F2 is applied to the shape memory member 20 in a direction parallel to the central axis of the shape memory member 20. It shows how it is done. This external force F2 is smaller than the restoring force that the shape memory member 20 tries to return to the memory shape.

On the left side of FIG. 4, the switch 54 of the control unit 50 is in the OFF state, and the shape memory member 20 is in the first phase in the soft state. In the first phase, the shape memory member 20 is easily deformed according to the external force F2. The shape memory member 20 is compressed by the external force F2. In other words, the shape memory member 20 is bent, and its length, that is, the dimension along the central axis is reduced.

4, when the switch 54 of the control unit 50 is switched to the on state, the induction member 30 generates heat, and the shape memory member 20 changes to the second phase that is in the hard state. In this second phase, the shape memory member 20 tends to take a memory shape. Since the external force F2 is smaller than the restoring force of the shape memory member 20, the shape memory member 20 returns to the memory shape, that is, the original linear length against the external force F2.

FIG. 5 shows how the presence / absence of an external force is switched in the first phase where the switch 54 of the control unit 50 is in the OFF state and the shape memory member 20 is in the soft state. In the first phase, the shape memory member 20 is easily deformed according to an external force.

On the left side of FIG. 5, the external force F <b> 1 acts on the portion of the shape memory member 20 near the lower end of the induction member 30 in a direction perpendicular to the central axis of the shape memory member 20. The shape memory member 20 is bent by the external force F1.

On the right side of FIG. 5, the external force F1 that has been acting on the shape memory member 20 until then is removed. The shape memory member 20 remains bent after the external force F1 is removed.

FIG. 6 shows a state where the hardness state of the bent shape memory member 20 is changed from the soft state to the hard state in accordance with switching of the switch 54 of the control unit 50.

The left side of FIG. 6 shows the same state as the right side of FIG. 5, that is, the shape memory member 20 is bent by the external force F1, and then the external force F1 is removed and remains bent.

As shown on the right side of FIG. 6, when the switch 54 of the control unit 50 is switched to the on state, the induction member 30 generates heat, and the shape memory member 20 changes to the second phase that is in the hard state. In this second phase, the shape memory member 20 shows a tendency to take a memory shape, so that the shape memory member 20 returns to a memory shape, that is, a linear shape.

FIG. 7 shows a state in which the presence or absence of an external force is switched in a situation where the switch 54 of the control unit 50 is in the ON state and the shape memory member 20 is in the second phase in the hard state. In this second phase, the shape memory member 20 tends to take a memory shape.

7 shows a state in which an external force F3 acts on a portion of the shape memory member 20 near the lower end of the induction member 30 in a direction perpendicular to the central axis of the shape memory member 20 on the left side of FIG. The external force F3 is larger than the restoring force that the shape memory member 20 tries to return to the memory shape. For this reason, although the shape memory member 20 tries to return to the memory shape against the external force F3, the external force F3 exceeds the restoring force of the shape memory member 20, so the shape memory member 20 is bent by the external force F3. .

On the right side of FIG. 7, the external force F3 that has been acting on the shape memory member 20 until then is removed. Since the external force F3 larger than the restoring force of the shape memory member 20 is removed, the shape memory member 20 returns to the memory shape, that is, the linear shape.

[Explanation of mounting method and operation of variable hardness actuator]
The above-described hardness variable actuator 10 is attached to the flexible member without any restriction on both ends of the shape memory member 20. For example, the hardness variable actuator 10 is arranged with a small gap in a limited space of the flexible member such that one end or both ends of the shape memory member 20 are free ends.

Here, the limited space means a space that can just accommodate the variable hardness actuator 10. Therefore, even if the deformation of one of the variable hardness actuator 10 and the flexible member is slight, it can contact the other and apply an external force.

For example, the flexible member is a tube having an inner diameter slightly larger than the outer diameter of the variable hardness actuator 10, and the variable hardness actuator 10 may be disposed inside the tube. However, the present invention is not limited to this, and the flexible member only needs to have a space slightly larger than the hardness variable actuator 10.

When the shape memory member 20 is in the first phase, the variable hardness actuator 10 provides a relatively low hardness to the flexible member, and thus an external force acting on the flexible member, that is, a force capable of deforming the shape memory member 20. Easily deforms according to.

Further, when the shape memory member 20 is in the second phase, the variable hardness actuator 10 provides a relatively high hardness to the flexible member and deforms the external force acting on the flexible member, that is, the shape memory member 20. The tendency to return to the memory shape against the obtained force is shown.

For example, when the control unit 50 switches the phase of the shape memory member 20 between the first phase and the second phase, the hardness of the flexible member is switched.

In addition to switching the hardness, under a situation in which an external force is acting on the flexible member, the variable hardness actuator 10 also functions as a bidirectional actuator that switches the shape of the flexible member. In addition, in the situation where no external force is acting on the flexible member and the flexible member is deformed in the first phase before the phase of the shape memory member 20 is switched to the second phase, It also functions as a unidirectional actuator that restores the shape of the flexible member.

[Second Embodiment]
FIG. 8 shows a hardness variable actuator according to the second embodiment. FIG. 9 is an enlarged view of a part of the hardness variable actuator shown in FIG. 8 and 9, members denoted by the same reference numerals as those shown in FIG. 1 are similar members, and detailed description thereof is omitted. In the following, explanation will be given with emphasis on the different parts. That is, the part which is not touched by the following description is the same as that of 1st embodiment.

The variable hardness actuator 10A of the present embodiment includes a cylindrical flexible conductive member 70 extending between the shape memory member 20 and the induction member 30. The shape memory member 20 has a wire shape, and the conductive member 70 is disposed symmetrically with respect to the central axis extending between the first end 22 and the second end 24 of the shape memory member 20. The conductive member 70 has a first end 72 located near the first end 22 of the shape memory member 20 and a second end 74 located near the second end 24 of the shape memory member 20. ing.

The conductive member 70 is electrically connected to the control unit 50 via the wiring 62 near the first end 72. The induction member 30 has conductivity, and the second end 34 of each induction member 30 is electrically connected to the conductive member 70 via the conduction member 68. The conducting member 68 can be configured by wiring, for example, similarly to the conducting member 66. However, the conducting member 68 is not limited to this and may be a structure that can be electrically connected. For example, caulking, welding, brazing, and the like. , Soldering, conductive adhesive, and the like.

[Third embodiment]
FIG. 10 shows a variable hardness actuator according to the third embodiment. 10, members denoted by the same reference numerals as those shown in FIG. 1 are similar members, and detailed description thereof is omitted. In the following, explanation will be given with emphasis on the different parts. That is, the part which is not touched by the following description is the same as that of 1st embodiment.

Similar to the hardness variable actuator 10, the hardness variable actuator 10B of the present embodiment has a shape memory member 20 ′ that can change phase between the first phase and the second phase, and the shape memory member 20 ′ has a first phase. And a plurality of induction members 30 ′ that cause a phase transition between the first phase and the second phase.

Various characteristics of the shape memory member 20 ′ are the same as those of the shape memory member 20. Various characteristics of each induction member 30 ′ are the same as those of the induction member 30.

The shape memory member 20 ′ has a pipe shape. The induction member 30 'is a wire shape that can be easily deformed, and extends through the inside of the shape memory member 20'. Thanks to this arrangement, the heat generated by the inducing member 30 'is efficiently transferred to the shape memory member 20'. Further, since the elastic modulus of the shape memory member 20 ′ depends on the radial dimension, the pipe-shaped shape memory member 20 ′ has a higher elastic modulus under the same volume condition than that of the solid structure. Shown and therefore provides high hardness.

The shape memory member 20 ′ has a first end 22 ′ and a second end 24 ′, and each induction member 30 ′ is located on the first end 22 ′ side of the shape memory member 20 ′. One end 32 'and a second end 34' located on the second end 24 'side of the shape memory member 20'. Both the shape memory member 20 ′ and the induction member 30 ′ have conductivity, and each induction member 30 ′ is connected to the control unit 50 near the first end 32 ′. And are electrically connected. Each inducing member 30 'is electrically connected to the shape memory member 20' via a conducting member 66 'near the second end 34'. The shape memory member 20 ′ is electrically connected to the wiring 62 that is electrically connected to the control unit 50. The conducting member 66 ′ can be constituted by wiring, for example, similarly to the conducting member 66. However, the conducting member 66 ′ is not limited to this and may be any structure that can be electrically connected. For example, caulking, welding, brazing, and the like. It may be configured by attaching, soldering, conductive adhesive, or the like.

Claims

A hardness variable actuator that is mounted on a flexible member and can provide different hardness to the flexible member;
A shape memory member that can change phase between the first phase and the second phase is provided, and when the shape memory member is in the first phase, the shape memory member has a soft state that can be easily deformed according to an external force. And thus providing a relatively low hardness to the flexible member, and when in the second phase, takes a hard state showing a tendency to take a pre-stored memory shape against external forces, Therefore, providing the flexible member with a relatively high hardness,
A plurality of inducing members for causing the shape memory member to cause a phase transition between the first phase and the second phase;
One end of each of the plurality of induction members is a variable hardness actuator that is electrically connected to a common conductive member.
2. The hardness variable actuator according to claim 1, wherein the conductive member is disposed symmetrically with respect to a central axis of the shape memory member.
2. The hardness variable actuator according to claim 1, wherein the shape memory member has conductivity, and the shape memory member is also the conductive member.
2. The hardness variable actuator according to claim 1, wherein the conductive member is made of a conductive material including the shape memory member.