JP4855364B2 - Actuator - Google Patents

Description

  The present invention relates to an actuator having a configuration in which a moving part is moved along with expansion and contraction of a shape memory alloy.

  In recent years, endoscopes are widely used in the medical field and the industrial field. The endoscope can observe the inside of the duct by inserting an elongated insertion portion into the duct.

  In addition, an endoscope, for example, an objective optical system composed of a plurality of objective lens groups for observing the inside of a duct, or a solid-state imaging device such as a CCD, is disposed in the distal end portion in the insertion direction of an insertion portion of an electronic endoscope. In general, an imaging device including an element or the like is provided, and the electronic endoscope has a configuration in which an image of an observation site in a duct formed by an objective optical system is captured by the imaging device. It has become.

  Furthermore, by making at least one of the plurality of objective lens groups in the objective optical system a movable lens that is movable with respect to the optical axis direction of the objective optical system, the movable lens is moved in the optical axis direction. In addition, zoom endoscopes that can vary optical characteristics such as depth of focus, observation magnification, and viewing angle with respect to the observation site of the objective optical system are also well known. If observation is performed using a zoom endoscope, for example, in the case of a medical endoscope, it is possible to observe the structure of the mucous membrane and capillaries at the observation site in the body cavity.

  Here, various mechanisms for moving the moving lens serving as the moving member in the optical axis direction have been proposed. For example, in Patent Document 1, one end of a shape memory alloy (Shape Memory Alloys, hereinafter referred to as SMA) wire extending in the optical axis direction is fixed to a protrusion formed integrally with a moving lens frame having a moving lens, A technique is disclosed in which an SMA wire is expanded or contracted in the optical axis direction by moving the SMA wire in an energized state or a non-energized state, and the moving lens is moved in the optical axis direction. That is, a technique for moving the moving lens in the optical axis direction using an actuator having an SMA wire is disclosed.

Further, in Patent Document 2, a moving magnet folder is fixed to a moving lens barrel that holds a moving lens, and a driven magnet is provided in the moving magnet folder along the optical axis direction. In addition, a driving magnet folder for holding a driving magnet movable in a clockwise direction and a counterclockwise direction is provided on the outer peripheral side in the radial direction of the moving lens, and the N pole of the driving magnet and the driven magnet A technique for moving the moving lens in the optical axis direction using repulsion with the N pole or repulsion between the S pole of the driving magnet and the S pole of the driven magnet is disclosed. That is, a technique for moving a moving lens in the optical axis direction using an actuator having a driven magnet and a driving magnet is disclosed.
JP 2004-129950 A JP 2005-003867 A

  By the way, when the actuator including the SMA wire disclosed in Patent Document 1 described above is used, for example, when the moving lens is moved to the rearmost side in the optical axis direction to set the observation magnification to the maximum magnification, the SMA wire is used. Although it is well known that the control is performed by controlling the energization amount, that is, by controlling the contraction amount of the SMA wire, the control of the energization amount becomes complicated.

  For this reason, normally, when the SMA wire is energized to contract the SMA wire and move the moving lens frame to the rearmost side in the optical axis direction, the moving lens frame comes into contact with the stopper member. Further, it is general to use a configuration in which the moving lens does not move backward from the position corresponding to the maximum magnification even when the SMA wire is contracted.

  However, when the stopper member is used in this manner, the SMA wire contracts even after the moving lens frame contacts the stopper member, so that an excessive load is applied to the SMA wire and the durability of the SMA wire is reduced. As a result, there is a problem that the durability of the actuator is lowered.

  Furthermore, if the SMA wire contracts even after the moving lens frame comes into contact with the stopper member, the SMA wire is excessively heated. In this state, the amount of contraction of the SMA wire per unit temperature is reduced or contracted. No longer. For this reason, when the SMA wire is de-energized from an excessively heated state and the SMA wire is cooled, it takes time until the SMA wire expands, that is, the response of the actuator having the SMA wire. There was also a problem that the speed decreased.

  Further, in the configuration disclosed in Patent Document 2 described above, since it is necessary to dispose the driving magnet and the driven magnet in the radial direction of the moving lens, the actuator including the driving magnet and the driven magnet is provided. There has been a problem that it is difficult to reduce the size in the radial direction.

  The present invention has been made in view of the above problems, and in a configuration in which a moving member is moved using an SMA wire and a position of the moving member is defined using a stopper member, the response speed is reduced and durability is reduced. It is an object of the present invention to provide an actuator having a configuration capable of preventing a decrease and realizing a reduction in size in a radial direction of a moving member to be moved.

In order to achieve the above object, an actuator according to an aspect of the present invention includes a magnet that moves together with a moving unit in front and rear in the moving direction of the moving unit , and extends in the moving direction in a non-energized state. A shape memory alloy wire that contracts in the moving direction, a fixture made of a magnetic material that is attached to the tip of the shape memory alloy wire and can be attracted to the magnet by a magnetic force, and the fixing tool in the moving direction . wherein the shape comprises a spring for biasing the magnet to the front, and a stopper portion for restricting the movement of the magnet definitive in the moving direction at the set position, the said moving part, that extends in the non-energized state The fixture, to which the magnet is attracted by the memory alloy wire and the spring, is moved forward by being biased forward, and the energized state The shape memory alloy wire that is contracted in the magnet is configured to move rearward by moving rearward in the moving direction, and the shape memory alloy in the non-energized state. When the wire is stretched, the magnet to which the fixing tool is attracted is moved forward in the moving direction with respect to the stopper portion due to the bias of the spring, and the shape memory alloy wire contracts in the energized state. At this time, the magnet moved to the rear while the fixing tool is attracted at the set position comes into contact with the stopper portion, and moves further to the rear when the shape memory alloy wire is contracted further than the set position. The fixture is separated from the magnet.
The actuator according to another aspect of the present invention includes a magnet that moves together with the moving unit in the moving direction of the moving unit, and expands in the moving direction in the non-energized state, and in the moving direction in the energized state. A shape memory alloy wire that contracts, a fixture that is attached to the tip of the shape memory alloy wire and is made of a magnetic material that can be attracted to the magnet by a magnetic force, and the fixture is attached to the magnet forward in the moving direction. A spring for biasing the stopper, and a stopper portion for restricting the movement of the magnet in the moving direction at a set position, the moving portion extending in the non-energized state and the spring The fixing tool to which the magnet is attracted is moved forward by being biased forward, and contracts in the energized state. The fixture attracted to the magnet by the shape memory alloy wire is configured to move backward by moving backward in the moving direction, and the shape memory alloy wire is stretched in the non-energized state. When the magnet is attracted to the fixing member due to the bias of the spring, the magnet is separated forward in the moving direction with respect to the stopper portion, and when the shape memory alloy wire contracts in the energized state, At the set position, the magnet moved to the rear while the fixing tool is attracted contacts the stopper portion, and the contact state is detected, so that the amount of current applied to the shape memory alloy wire becomes the shape memory alloy wire. Is controlled to contract by a set amount from the extended state in the non-energized state to the contracted state at the set position in the energized state. It is.

  According to the present invention, in the configuration in which the moving member is moved using the SMA wire and the position of the moving member is defined using the stopper member, it is possible to prevent the response speed from being lowered and the durability from being lowered and moved. It is possible to provide an actuator having a configuration capable of realizing a reduction in size in the radial direction of a target moving member.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiment, the actuator will be described as being used for an endoscope.

(First embodiment)
FIG. 1 is a partial cross-sectional view showing a distal end side of an endoscope having an actuator according to the present embodiment, and FIG. 2 is a partial cross-sectional view of the endoscope front end side along the line II-II in FIG. FIG. 3 is a partial cross-sectional view of the endoscope distal end side along the line III-III in FIG.

  As shown in FIG. 1, a substantially cylindrical tip folder 4 is provided in the distal end portion 1 of the endoscope along the insertion direction S of the endoscope. A plurality of through-holes are formed along.

  As shown in FIG. 3, a treatment instrument insertion channel 2 that also serves as a suction conduit, a cleaning nozzle 41 that sprays fluid on the objective lens and cleans it, as shown in FIG. Illumination optical systems 42a and 42b for illuminating the examination site, an angle wire 43, an imaging device 50, and the like are provided. The configuration, function, and the like of the channel 2, the cleaning nozzle 41, the illumination optical systems 42a and 42b, and the angle wire 43 are well known, and thus the description thereof is omitted in the present embodiment.

  Next, the configuration of the imaging device 50 provided in the through hole of the tip folder 4 will be described. The configuration of the imaging device 50 is also well known and will be described schematically.

  In the imaging device 50, a nonmagnetic member made of a nonmagnetic material is provided on the outer periphery of a midway position along the insertion direction S of the first lens frame 5 that holds the objective lens group 3 including a plurality of objective lenses. A certain second lens frame 32 is fitted.

  In addition, a stopper member 70 that defines a movement position of the magnet 8, which will be described later, in the insertion direction S in the insertion direction S is fitted on the outer periphery of the second lens frame 32 in the insertion direction S. That is, the stopper member 70 defines a moving position of the moving lens frame 6 described later, more specifically, the moving position of the moving lens 7 toward the distal end side in the moving direction I. Specifically, the moving lens 7 is defined at a position corresponding to the same magnification (1 ×).

  Further, the moving lens frame 6, which is a moving unit that holds the moving lens 7, is moved along the insertion direction S in the sealed space 32 m by the second lens frame 32 on the inner periphery of the second lens frame 32. I is provided so as to be movable.

  Further, in the imaging device 50, a known solid-state imaging device 10, an electric board 11, a signal cable 12, and the like are provided behind the moving lens 7 in the insertion direction S. Further, a stopper portion 32p formed of a step portion is formed on the outer periphery at the lower position in FIG. 1 at a midway position along the insertion direction S of the second lens frame 32.

  The stopper portion 32p defines the movement position of the magnet 8 toward the rear end side in the insertion direction S. That is, the stopper portion 32p moves toward the rear end side of the moving lens frame 6, more specifically the moving lens 7 in the moving direction I. Define the movement position of. Specifically, the moving lens 7 is defined at a position corresponding to the maximum magnification.

  In addition, the actuator 100 is provided along with the imaging device 50 in the through hole provided with the imaging device 50 formed in the front end folder 4.

  As shown in FIG. 2, the actuator 100 includes a magnet 8, an SMA wire 14, a fixture 9, and a lower lens frame 32 provided in the outer peripheral direction of the moving lens frame 6 via a second lens frame 32. The pressing spring 16, the stopper portion 32p formed on the second lens frame 32 and the stopper member 70 constitute a main portion.

  The magnet 8, the SMA wire 14, the fixture 9, the pressing spring 16, the stopper portion 32p, and the stopper member 70 are arranged in a straight line along the moving direction I as shown in FIG.

  The magnet 8 moves in the moving direction I together with the moving lens frame 6 by magnetic force. The SMA wire 14 expands and contracts in the moving direction I of the moving lens frame 6 with or without energization. Specifically, the SMA wire 14 contracts in the moving direction I when heated, and expands in the moving direction I when cooled. It is a wire with a constructed diameter of several tens of microns.

  The SMA wire 14 is inserted into a guide pipe 15 and a first insulating tube 17 provided along the insertion direction S. The distal end side of the first insulating tube 17 in the insertion direction S is fitted and fixed to the inner periphery of the proximal end side of the guide pipe 15 in the insertion direction S.

  One end of the SMA wire 14 is crimped by a first crimping portion 25 made of a cylindrical metal ring. A driving cable 26 for supplying current to the SMA wire 14 is electrically connected to the first crimping portion 25 by solder. Although not shown, the periphery of the connecting portion between the first caulking portion 25 and the driving cable 26 is reinforced with an adhesive or the like.

  The first caulking portion 25 is attached to the distal end in the insertion direction S of a flexible tube portion (not shown) connected to a bending portion on the proximal end side in the insertion direction S with respect to the bending portion (not shown) of the endoscope. It is provided at the side position.

  The SMA wire 14 is bent so as to be inserted in a groove (not shown) formed in the fixture 9 and folded along the insertion direction S at a midway position. The portion of the SMA wire 14 inserted into the groove of the fixture 9 is bonded and fixed to the fixture 9 by the ball 13.

  The other end of the SMA wire 14 that has been folded back is crimped by a second crimping portion 29 made of a cylindrical metal ring. A GND cable 28 is electrically connected to the second caulking portion 29 by solder.

  A ring-shaped anchor 19 is inserted into a part of the outer periphery of the first insulating tube 17 and the GND cable 28 (in FIG. 2, the anchor 19 provided on a part of the outer periphery of the GND cable 28 is (Not shown in the figure), which are bonded and fixed to a part of each outer periphery.

  Further, as shown in FIG. 1, a protective tube 22 is attached to the first insulating tube 17 and the GND cable 28 so as to cover the anchor 19 and the first insulating tube 17. The distal end side in the insertion direction S of the protective tube 22 is fixed to the first insulating tube 17 by a thread binding 18 made of Teggs or the like.

  The fixture 9 is attached to the tip of the SMA wire 14 in the moving direction I, and is made of a magnetic material.

  The pressing spring 16 is provided between the first insulating tube 17 and the fixture 9 inside the guide pipe 15. The pressing spring 16 biases the fixture 9 toward the magnet 8 along the moving direction I. As a result, the fixture 9 made of a magnetic material can be attracted to the magnet 8 by a magnetic force.

  Next, the effect | action of this Embodiment comprised in this way is demonstrated using FIGS. 4-6 with FIGS. 1-3 mentioned above. 4 is a partial sectional view of the distal end side of the endoscope showing a state in which the magnet of FIG. 1 is in contact with the stopper portion of the second lens frame, and FIG. 5 is a diagram of the magnet of FIG. FIG. 6 is a partial cross-sectional view of the distal end side of the endoscope showing a state in which the fixture is moved away from the magnet while being in contact with the stopper portion. FIG. It is a chart shown as a hysteresis curve.

  First, when the moving lens 7 is positioned at the first position Ia, which is a set position corresponding to the same magnification (1 ×), the SMA wire 14 of the actuator 100 is in a non-energized state. As a result, the SMA wire 14 extends toward the distal end side in the moving direction I, and as shown in FIG. In the attracted state, the magnet 8 is pressed against the stopper member 70. As a result, the moving position of the moving lens frame 6 and the moving lens 7 is fixed at the first position Ia corresponding to the most distal side in the moving direction I, that is, equal magnification (1 time) in the moving range Ia to Ib. . At this time, the strain amount of the SMA wire 14 is εa, and the temperature is t1. At this time, the magnet 8 and the stopper portion 32p are separated from each other.

  Next, when the moving lens 7 is moved to the second position Ib corresponding to the maximum magnification, that is, when the moving lens 7 is moved rearward in the moving direction I, the actuator 100 is operated from a power source (not shown). Then, a current is supplied to the drive cable 26.

  Thereafter, the current flows through the drive cable 26, the first caulking portion 25, the SMA wire 14, the second caulking portion 29, and the GND cable 28, the SMA wire 14 generates heat, and the curve (a) in FIG. As shown, the SMA wire 14 shrinks so that the strain amount with respect to the temperature t1 to t2 becomes εa to εb.

  As a result, the fixture 9 to which the SMA wire 14 is fixed moves rearward in the movement direction I, and the magnet 8 that has been attracted to the fixture 9 with magnetic force is also attracted to the fixture 9 and rearward in the movement direction I. Moving. Further, the moving lens frame 6 and the moving lens 7 are also moved rearward in the moving direction I in the sealed space 32 m by the magnetic force of the magnet 8.

  As shown in FIG. 4, the magnet 8 abuts on the stopper portion 32 p of the second lens frame 32. At this time, the strain amount of the SMA wire 14 is εb, and the temperature is t2. Further, due to the stopper portion 32p, even if the SMA wire 14 is further contracted, the magnet 8 does not move to the rear side in the moving direction I from the second position Ib that is a set position in contact with the stopper portion 32p. That is, the rearmost position in the moving range of the moving lens frame 6 and the moving lens 7 that have moved rearward in the moving direction I by the magnetic force of the magnet 8 is defined. In other words, the moving lens 7 is moved to the second position Ib corresponding to the maximum magnification, and the moving position is fixed. At this time, the magnet 8 and the stopper member 70 are separated from each other.

  In a state where the magnet 8 is in contact with the stopper portion 32p at the second position Ib, the strain amount of the SMA wire 14 with respect to the temperature t2 to t3 is εb˜ as shown in the curve (a) of FIG. When contracted to εc, the fixture 9 moves away from the magnet 8 and moves to, for example, the third position Ic behind the moving direction I, as shown in FIG.

  At this time, the fixing tool 9 is separated from the magnet 8, so that the magnet 8 remains in contact with the stopper portion 32p, and the moving lens frame 6 and the moving lens 7 remain in the second position Ib. is there.

  Further, since the fixture 9 is separated from the magnet 8, that is, when the magnet 8 is in contact with the stopper portion 32p, the magnet 8 is not pulled by the contraction of the SMA wire 14. There is no excessive load.

  Even if the fixture 9 is separated from the magnet 8, the magnet 8 is in contact with the stopper portion 32p. If the fixture 9 is not largely separated in the moving direction I, the fixture 9 and the magnet 8 are not separated. This is because a magnetic force acts between them, and the moving lens frame 6 abuts the inner periphery of the second lens frame 32 with a frictional force due to the magnetic force between the magnet 8 and the moving lens frame 6. .

  Also, assuming that the strain amount of the SMA wire 14 at the third position Ic is εc and the temperature is t3, the SMA wire 14 has the magnet 8 in contact with the stopper portion 32p as shown in the curve (a) of FIG. Thereafter, when distortion occurs from the second position Ib to the third position Ic, the amount of strain (εb to εc) per unit temperature (t2 to t3) is the unit temperature from the first position Ia to the second position Ib. It can be seen that the strain amount per (t1 to t2) (εa to εb) is not so different.

  When the SMA wire 14 contracts from the third position Ic, the strain amount per unit temperature is the strain from the first position Ia to the third position Ic, as shown by the curve (a) in FIG. It can be seen that it is smaller or less distorted than the quantities εa-εc.

  That is, in the present embodiment, as shown in FIG. 6, when the fixture 9 is moved from the first position Ia to the third position Ic, the SMA wire 14 per unit temperature in the temperature range t1 to t3. Since the SMA wire 14 is contracted within a range where the strain amount is substantially constant εa to εc, in other words, the overheated state in which the SMA wire 14 is contracted until the strain amount becomes εc or more. Therefore, as shown in the curve (a) of FIG. 6, when the SMA wire 14 is de-energized, the strain amount is immediately reduced as compared with the case where the SMA wire 14 is contracted to εc or more. It can be seen immediately that the SMA wire 14 is stretched.

  When the energization to the SMA wire 14 is stopped at the third position Ic shown in FIG. 5, the fixing spring 9 is moved forward by the pressing spring 16 until the fixture 9 is attracted to the magnet 8 with magnetic force at the second position Ib. Move to the side. At this time, the SMA wire 14 is stretched so that the strain amount of the SMA wire 14 becomes εc to εb as shown by a curve (b) in FIG.

  Further, from the second position Ib shown in FIG. 4, the magnet 8 moves to the tip side in the moving direction I by the pressing spring 16 until it abuts against the stopper member 70 at the first position Ia. At this time, the moving lens frame 6 and the moving lens 7 also move in the movement direction I from the second position Ib to the first position Ia. Further, the SMA wire 14 is stretched so that the strain amount of the SMA wire 14 becomes εb to εa as shown by a curve (b) in FIG.

  Here, as shown in curves (a) and (b) of FIG. 6, when the SMA wire 14 is contracted and expanded, the curves (a) and (b) do not match. That is, the difference in the amount of strain per unit temperature between shrinkage and extension is due to a known hysteresis phenomenon.

  As described above, in the present embodiment, in the actuator 100, the magnet 8, the SMA wire 14, the fixture 9, the pressing spring 16, the stopper portion 32 p, and the stopper member 70 are aligned along the moving direction I. When the magnet 8 is in contact with the stopper member 70, the moving lens 7 and the moving lens frame 6 that move in the moving direction I in the sealed space 32m by the magnetic force of the magnet 8 are in the first position. When the magnet 8 is in contact with the stopper portion 32p due to the contraction of the SMA wire 14 due to the contraction of the SMA wire 14, the moving lens 7 and the moving lens frame 6 are positioned at the second position Ib by the magnetic force of the magnet 8. It showed. Furthermore, it has been shown that when the SMA wire 14 is contracted more than the second position Ib, the fixture 9 is separated from the magnet 8.

  According to this, since the magnet 8, the SMA wire 14, the fixture 9, the pressing spring 16, the stopper portion 32 p, and the stopper member 70 are arranged in a straight line along the moving direction I, the actuator 100 becomes longer in the moving direction I, but does not become larger in the radial direction. Therefore, the actuator 100 can be made smaller than before.

  Further, when the SMA wire 14 is contracted from the second position Ib, the fixing tool 9 is separated from the magnet 8, so that the magnet 8 is in contact with the stopper portion 32 p, and the magnet 8 is fixed to the fixing tool 9. In addition, since the SMA wire 14 is not pulled backward in the movement direction I, it is possible to prevent the SMA wire 14 from being applied with a large uncontrollable force and applied with a large load. Can be improved.

  Furthermore, in this Embodiment, it showed that the SMA wire 14 was contracted in the temperature range t1-t3 which does not become an overheating state.

  According to this, when current is supplied to the SMA wire 14 and contracted, when the SMA wire 14 is de-energized and de-energized, the SMA wire 14 expands with a constant strain amount. Therefore, the SMA wire 14 can be stretched by increasing the response speed. As a result, the response speed of the actuator 100 is improved.

  In the present embodiment, the moving lens 7 and the moving lens frame 6 are shown to be movable in the moving direction I by the magnetic force of the magnet 8 in the sealed space 32 m of the second lens frame 32.

  According to this, since the fluid is prevented from entering the second lens frame 32, the airtightness is further improved.

  As described above, in the configuration in which the moving lens frame and the moving lens are moved using the SMA wire and the position of the moving lens frame and the moving lens is defined using the stopper portion, the response speed and the durability are prevented from being lowered. In addition, it is possible to provide an actuator having a configuration capable of realizing downsizing of the moving lens frame and the moving lens in the radial direction.

Hereinafter, modifications will be described.
In the present embodiment, when the movable lens frame 6 and the movable lens 7 are moved from the first position Ia to the second position Ib, the SMA wire 14 is contracted so that the magnet 8 contacts the stopper portion 32p. Thereafter, the fixture 9 is shown to be separated from the magnet 8.

  Not limited to this, the SMA wire 14 contracts by determining a target current amount by applying a minute voltage at the timing of pause of the current supplied to the SMA wire 14 and detecting a resistance value by a bridge circuit (not shown). It may be controlled.

  That is, the energization amount to the SMA wire 14 is controlled so as to contract by a set amount from the expanded state at the first position Ia when the SMA wire 14 is in the non-energized state to the contracted state at the second position Ib when in the energized state. It doesn't matter.

  Further, the contact (butting state) between the magnet 8 and the stopper portion 32p at the second position Ib is detected by a sensor such as a short detection circuit provided in the stopper portion 32p, and depending on the detection state, It may be controlled so that a constant amount of current is supplied to the SMA wire 14. The contact between the magnet 8 and the stopper portion 32p may be detected by detecting a change in the resistance value of the current supplied to the SMA wire 14.

  If the modified example described above is used, the SMA wire 14 is not contacted with the stopper portion 32p after the SMA wire 14 is contracted more than the second position Ib and the magnet 8 and the fixture 9 are not separated from each other. Since the supply of current to 14 is stopped, it is possible to prevent the SMA wire 14 from being loaded.

  Hereinafter, another modification will be described with reference to FIG. FIG. 12 is a partial cross-sectional view showing the distal end side of an endoscope including an actuator showing a modification of the present embodiment in which a stopper member is provided at the stopper portion shown in FIG.

  As shown in FIG. 12, a stopper member 132 made of a magnetic material may be provided at a portion of the stopper portion 32 p provided on the second lens frame 32. When the stopper member 132 made of a magnetic material is provided, the magnet 8 and the stopper member 132 are attracted by the magnetic force of the magnet 8 when the magnet 8 is moving to Ib. It stays at the position of Ib more reliably than the form of.

(Second Embodiment)
FIG. 7 is a partial cross-sectional view of the distal end side of the endoscope having the actuator according to the present embodiment, and FIG. 8 is an inner view showing a state where the magnet of FIG. 7 is in contact with the stopper portion of the second lens frame. FIG. 9 is a partial cross-sectional view of the distal end side of the endoscope, and FIG. 9 is an endoscope showing a state in which the fixing tool is moved away from the magnet while the magnet of FIG. 7 is in contact with the stopper of the second lens frame. It is a fragmentary sectional view by the side of the tip.

  The configuration of the actuator of the second embodiment is different from that of the actuator of the first embodiment shown in FIGS. 1 to 6 described above in that the magnet is directly attracted to the moving lens frame by a magnetic force. . Therefore, only this difference will be described, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted.

  As shown in FIG. 7, in the present embodiment, the moving lens 47 is held by a moving lens frame 46 that is a moving unit made of a magnetic material, and the moving lens frame 46 is a second lens frame. 32 is provided so as to be movable in the movement direction I.

  Further, a notch 49 is formed along the movement direction I below the second lens frame 32 in FIG. 7, and the magnet coupling rod 48 in the actuator 200 moves by magnetic force via the notch 49. It is directly attracted to the lens frame 46. Other configurations are the same as those in the first embodiment described above.

Next, the operation of the present embodiment configured as described above will be described.
First, when the moving lens 7 is positioned at the first position IIa, which is a setting position corresponding to the same magnification (1 ×), the SMA wire 14 of the actuator 200 is in a non-energized state. As a result, the SMA wire 14 extends toward the distal end side in the moving direction I, and as shown in FIG. 7, the fixing tool 9 is pressed toward the distal end side in the moving direction I by the pressing spring 16, and by magnetic force, The magnet coupling rod 48 is pressed against the stopper member 70 while being attracted to the magnet coupling rod 48. As a result, the moving position of the moving lens frame 46 and the moving lens 47 is fixed at the first position IIa corresponding to the most distal side in the moving direction I, that is, equal magnification (1 time) in the moving ranges IIa to IIb. . At this time, the magnet coupling rod 48 and the stopper portion 32p are separated from each other.

  Next, when the moving lens 47 is moved to the second position IIb corresponding to the maximum magnification, that is, when the moving lens 47 is moved rearward in the moving direction I, the actuator 200 is operated from a power source (not shown). Then, a current is supplied to the drive cable 26.

  Thereafter, the current flows through the drive cable 26, the first caulking portion 25, the SMA wire 14, the second caulking portion 29, and the GND cable 28, and the SMA wire 14 generates heat and contracts.

  As a result, the fixing tool 9 moves rearward in the moving direction I, and the magnet connecting rod 48 attracted to the fixing tool 9 with magnetic force is also attracted to the fixing tool 9 in the moving direction I through the notch 49. Move backwards. Further, the moving lens frame 46 and the moving lens 47 also move rearward in the moving direction I through the notch 49 by the magnetic force of the magnet coupling rod 48.

  As shown in FIG. 8, the magnet coupling rod 48 contacts the stopper portion 32 p of the second lens frame 32. Further, due to the stopper portion 32p, even if the SMA wire 14 contracts, the magnet coupling rod 48 does not move to the rear side in the movement direction I from the second position IIb that is a set position where the magnet coupling rod 48 contacts the stopper portion 32p. That is, the rearmost position in the moving range of the moving lens frame 46 and the moving lens 47 that have moved rearward in the moving direction I is defined by the magnetic force of the magnet coupling rod 48. In other words, the moving lens 47 is moved to the second position IIb corresponding to the maximum magnification, and the moving position is fixed. At this time, the magnet coupling rod 48 and the stopper member 70 are separated from each other.

  When the SMA wire 14 is further contracted in the state where the magnet coupling rod 48 is in contact with the stopper portion 32p at the second position IIb, the fixture 9 is separated from the magnet coupling rod 48 as shown in FIG. For example, it moves to the third position IIc behind the moving direction I.

  At this time, the fixture 9 is separated from the magnet coupling rod 48, so that the magnet coupling rod 48 remains in contact with the stopper portion 32p, and the movable lens frame 46 and the movable lens 47 are moved to the second position IIb. Stays in place.

  Further, the fixing device 9 is not separated from the magnet connection rod 48, that is, when the magnet connection rod 48 is in contact with the stopper portion 32p, the magnet connection rod 48 is not pulled by the SMA wire 14 due to contraction. Therefore, an unreasonable load is not applied to the SMA wire 14.

  When the energization to the SMA wire 14 is stopped at the third position IIc shown in FIG. 9, the pressing spring 16 causes the fixing tool 9 to move in the moving direction I until the magnet 9 is attracted to the magnet coupling rod 48 at the second position IIb. Move to the tip side. At this time, the SMA wire 14 is stretched.

  Further, from the second position IIb shown in FIG. 8, the pressing spring 16 causes the magnet coupling rod 48 to move forward through the notch 49 until it abuts against the stopper member 70 at the first position IIa. Move to. At this time, the moving lens frame 46 and the moving lens 47 also move in the movement direction I from the second position IIb to the first position IIa. Further, the SMA wire 14 further expands. Other operations are the same as those in the first embodiment described above.

  Thus, in the present embodiment, it has been shown that the magnet coupling rod 48 is directly attracted to the moving lens frame 46 by the magnetic force through the notch 49. According to this, airtightness with respect to the moving lens frame 46 is reduced by the provision of the notch 49 as compared with the first embodiment described above, but the moving lens frame 46 moves along the moving direction I. At this time, since frictional resistance does not occur between the magnet coupling rod 48 and the second lens frame 32, the magnet coupling rod 48 can be moved more smoothly than in the first embodiment. That is, it is possible to provide the actuator 200 with excellent response speed. Other effects are the same as those of the first embodiment described above.

  In the second embodiment, an example in which the second lens frame 32 and the magnet coupling rod 48 are adsorbed by magnetic force is shown. However, the second lens frame 32 and the magnet coupling rod 48 are bonded with an adhesive. It may be fixed. Since the lens frame 32 and the magnet coupling rod 48 do not come off when bonded, the magnetic force of the magnet coupling rod 48 may be weak, so that the magnet coupling rod 48 can be made smaller.

(Third embodiment)
10 is a partial cross-sectional view of the distal end side of the endoscope having the actuator according to the present embodiment, and FIG. 11 is an internal view showing a state where the magnet of FIG. 10 is attracted to the rear magnet of the second lens frame. It is a fragmentary sectional view by the side of the tip of a mirror.

  Compared with the actuator of the second embodiment shown in FIGS. 7 to 9 described above, the configuration of the actuator of the third embodiment is such that the magnet coupling rod is moved by the magnetic force to the first position and the second position. Is different in that it is moved in the moving direction. Therefore, only this difference will be described, the same reference numerals are given to the same components as those in the second embodiment, and the description thereof will be omitted.

  As shown in FIG. 10, in the present embodiment, a notch 49 is formed along the movement direction I below the second lens frame 32 in FIG. 10, and through the notch 49, The magnet coupling rod 58 in the actuator 300 is directly attracted to the moving lens frame 46 by magnetic force.

  Further, in the first position IIIa, a front magnet 57 is provided at a portion of the stopper member 70 with which the magnet coupling rod 58 abuts. The front magnet 57 is arranged so that the magnetic poles facing the magnet coupling rod 58 are different. That is, for example, the N pole of the front magnet 57 and the S pole of the magnet coupling rod 58 are arranged so as to face each other, and the S pole of the front magnet 57 and the N pole of the magnet coupling rod 58 are arranged to be separated from each other.

  Furthermore, a rear magnet 56 is provided at a portion of the second lens frame 32 with which the magnet coupling rod 58 abuts at the second position IIIb. The rear magnet 56 is arranged so that the magnetic poles facing the magnet coupling rod 58 are the same polarity. That is, for example, the N pole of the rear magnet 56 and the N pole of the magnet coupling rod 58 are arranged so as to face each other, and the S pole of the rear magnet 56 and the S pole of the magnet coupling rod 58 are arranged to be separated from each other.

  Further, in the present embodiment, the actuator 300 is configured not to use a pressing spring and a fixture unlike the second embodiment described above. That is, the tip of the SMA wire 14 in the insertion direction S is fixed to the magnet coupling rod 58. Other configurations are the same as those of the second embodiment described above.

Next, the operation of the present embodiment configured as described above will be described.
First, when the moving lens 7 is positioned at the first position IIIa, which is a set position corresponding to the same magnification (1 ×), the SMA wire 14 of the actuator 200 is set in a non-energized state. As a result, the SMA wire 14 extends toward the distal end side in the moving direction I, and the S pole of the magnet coupling rod 58 and the N pole of the front magnet 57 are attracted by magnetic force as shown in FIG.

  As a result, the moving position of the moving lens frame 46 and the moving lens 47 is fixed at the first position IIIa corresponding to the most distal side in the moving direction I, that is, equal magnification (1 time) in the moving ranges IIIa to IIIb. .

  Next, when the moving lens 47 is moved to the second position IIIb corresponding to the maximum magnification, that is, when the moving lens 47 is moved rearward in the moving direction I, the actuator 300 is operated from a power source (not shown). Then, a current is supplied to the drive cable 26.

  Thereafter, the current flows through the drive cable 26, the first caulking portion 25, the SMA wire 14, the second caulking portion 29, and the GND cable 28, and the SMA wire 14 generates heat and contracts.

  As a result, the magnet coupling rod 58 moves rearward in the moving direction I due to the contraction of the SMA wire 14. Further, the moving lens frame 46 and the moving lens 47 also move rearward in the moving direction I by the magnetic force of the magnet coupling rod 58.

  As shown in FIG. 11, the magnet coupling rod 58 contacts the rear magnet 56 of the second lens frame 32. At this time, since the magnetic poles of the magnet coupling rods 58 facing each other are N-poles and the magnetic poles of the rear magnet 56 are also N-poles, both repel each other, but the force with which the SMA wire 14 contracts is larger than the repulsive force. For this reason, the magnet coupling rod 58 contacts the rear magnet 56 of the second lens frame 32.

  Further, due to the rear magnet 56, even if the SMA wire 14 is further contracted, the magnet coupling rod 58 does not move to the rear side in the movement direction I from the second position IIIb. That is, the rearmost position in the moving range of the moving lens frame 46 and the moving lens 47 that have moved rearward in the moving direction I is defined by the magnetic force of the magnet coupling rod 58. In other words, the moving lens 47 is moved to the second position IIIb corresponding to the maximum magnification, and the moving position is fixed.

  Here, in the present embodiment, if the SMA wire 14 is further contracted in a state where the magnet coupling rod 58 is in contact with the rear magnet 56, there is a possibility that a load is applied to the SMA wire 14. However, as described above, if the energization amount is controlled for the SMA wire 14, it is possible to prevent the SMA wire 14 from being loaded.

  When the energization to the SMA wire 14 is stopped at the second position IIIb shown in FIG. 11, the magnet coupling rod 58 is repelled by the repulsion caused by the opposing magnet coupling rod 58 and the rear magnet 56 having the same polarity (N pole). The first position IIIa moves toward the front end side in the moving direction I until it is attracted to the front magnet 57. At this time, the moving lens frame 46 and the moving lens 47 also move in the moving direction I from the second position IIIb to the first position IIIa. Further, the SMA wire 14 extends. Other operations are the same as those of the second embodiment described above.

  As described above, in the present embodiment, at the first position IIIa, the front magnet 57 having the opposite magnetic pole different from the magnet coupling rod 58 is disposed on the stopper member 70 with which the magnet coupling rod 58 abuts, and the second position IIIa. It has been shown that at the position IIIb, the rear magnet 56 having the opposite magnetic pole and the same polarity as the magnet coupling rod 58 is disposed at the portion of the second lens frame 32 with which the magnet coupling rod 58 abuts.

  According to this, in the actuator 300, by disposing the front magnet 57 and the rear magnet 56 instead of the pressing spring, the actuator 300 can be reduced in size in the radial direction by the thickness in the radial direction of the pressing spring. it can. Moreover, since the structure is simplified, the assembly of the actuator 300 is facilitated. Other effects are the same as those of the third embodiment described above.

  In the first to third embodiments described above, the moving unit that is moved in the moving direction I by the actuator has been described by taking the moving lens frame that holds the moving lens as an example. It goes without saying that any moving part that is moved using an actuator may be used as long as it is moved in a shape.

  In the first to third embodiments described above, the actuator has been described as being used for an endoscope. However, the present invention is not limited thereto, and may be used for other objects. Nor.

The fragmentary sectional view which shows the front end side of the endoscope which comprises the actuator which shows 1st Embodiment. The fragmentary sectional view of the endoscope front end side which follows the II-II line in FIG. FIG. 3 is a partial cross-sectional view of the endoscope front end side along the line III-III in FIG. The fragmentary sectional view of the front end side of an endoscope which shows the state which the magnet of FIG. 1 contact | abutted to the stopper part of the 2nd lens frame. The fragmentary sectional view of the front end side of an endoscope which shows the state which the fixing tool moved away from the magnet in the state which the magnet of FIG. 4 contact | abutted to the stopper part of the 2nd lens frame. The graph which shows the change of the distortion amount with respect to the temperature of the SMA wire of FIG. 1 as a hysteresis curve. The fragmentary sectional view of the front end side of the endoscope which comprises the actuator which shows 2nd Embodiment. The fragmentary sectional view of the front end side of an endoscope which shows the state which the magnet of FIG. 7 contact | abutted to the stopper part of the 2nd lens frame. The fragmentary sectional view of the front end side of an endoscope which shows the state which the fixing tool moved away from the magnet in the state which the magnet of FIG. 7 contact | abutted to the stopper part of the 2nd lens frame. The fragmentary sectional view of the front end side of the endoscope which comprises the actuator which shows 3rd Embodiment. The fragmentary sectional view of the front end side of an endoscope which shows the state which the magnet of FIG. The fragmentary sectional view which shows the front end side of the endoscope which comprises the actuator which shows the modified example of this Embodiment which provided the stopper member in the site | part of the stopper part of FIG.

Explanation of symbols

6 ... Moving lens frame (moving part)
8 ... Magnet 9 ... Fixing tool 14 ... SMA wire (shape memory alloy wire)
16 ... Pressing spring 32 ... Second lens frame 32m ... Sealed space 32p ... Stopper part 46 ... Moving lens frame (moving part)
48 ... Magnet coupling rod 70 ... Stopper member 100 ... Actuator 200 ... Actuator I ... Moving direction Ia ... First position (set position)
IIa: First position (set position)
Ib ... 2nd position (setting position)
IIb ... 2nd position (setting position)

Claims (7)

A magnet that moves together with the moving part in the moving direction of the moving part ;
In a non-energized state, the shape memory alloy wire expands in the moving direction, and in the energized state contracts in the moving direction ;
A fixture made of a magnetic material attached to the tip of the shape memory alloy wire and capable of being attracted to the magnet by a magnetic force ;
A spring that biases the fixture toward the magnet forward in the moving direction;
A stopper portion for restricting the movement of the magnet definitive in the moving direction at the set position,
Equipped with,
The moving part moves forward when the fixing tool to which the magnet is attracted by the shape memory alloy wire and the spring that are stretched in the non-energized state is urged forward, and the energized state The fixture that is attracted to the magnet by the shape memory alloy wire that contracts in is configured to move backward by moving backward in the moving direction;
When the shape memory alloy wire is stretched in the non-energized state, the magnet to which the fixing tool is attracted is moved forward with respect to the stopper portion in the moving direction by the biasing of the spring,
When the shape memory alloy wire contracts in the energized state, the magnet moved to the rear while the fixing tool is attracted at the set position contacts the stopper portion, and the shape memory alloy is further moved from the set position. The actuator according to claim 1 , wherein when the wire is contracted, the fixing tool moving backward is separated from the magnet . The moving part is made of a magnetic material,
The actuator according to claim 1, wherein the magnet is moved forward and backward in the moving direction together with the moving portion by a magnetic force. A non-magnetic member is provided along the moving direction between the moving part and the magnet,
It said magnet, said non-magnetic material through the member, the actuator according to claim 1 or 2, characterized in that moves with the mobile unit in the mobile unit and the non-contact. A magnet that moves together with the moving part in the moving direction of the moving part;
In a non-energized state, the shape memory alloy wire expands in the moving direction, and in the energized state contracts in the moving direction;
A fixture made of a magnetic material attached to the tip of the shape memory alloy wire and capable of being attracted to the magnet by a magnetic force;
A spring that biases the fixture toward the magnet forward in the moving direction;
A stopper portion for restricting movement of the magnet in the moving direction at a set position;
Comprising
The moving part moves forward when the fixing tool to which the magnet is attracted by the shape memory alloy wire and the spring that are stretched in the non-energized state is urged forward, and the energized state The fixture that is attracted to the magnet by the shape memory alloy wire that contracts in is configured to move backward by moving backward in the moving direction;
When the shape memory alloy wire is stretched in the non-energized state, the magnet to which the fixing tool is attracted is moved forward with respect to the stopper portion in the moving direction by the biasing of the spring,
When the shape memory alloy wire in the energized state is contracted, the setting in position abuts on the magnet the stopper portion is moved to the rear while the fixture is adsorbed by Rukoto abutment condition is detected, characterized in that the energizing amount for the shape memory alloy wire, said shape memory alloy wire from said expanded state in a non-energized state, is controlled to contract by a set amount to a contracted state in the set position in the energized state Actuator. The actuator according to claim 4 , wherein the contact state is detected by detecting a change in a resistance value of a current passed through the shape memory alloy wire. The moving part is made of a magnetic material,
The actuator according to claim 4, wherein the magnet moves forward and backward in the moving direction together with the moving portion by a magnetic force. A non-magnetic member is provided along the moving direction between the moving part and the magnet,
The actuator according to any one of claims 4 to 6, wherein the magnet moves together with the moving unit without contact with the moving unit via the non-magnetic member.

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