JP2020051261A - Actuator - Google Patents

Abstract

To provide an actuator capable of suppressing deviation between a stator and a mover, and preventing falling of a wire.SOLUTION: A vibration actuator A includes a stator 10 and a mover 20 holding a wire 30 composed of shape memory alloy, a stator-side projection piece 11b is formed on a stator-side recessed portion 11 of the stator 10, a stator-side groove portion 12b is formed on a stator-side projection portion 12, a mover-side projection piece 21b is formed on a mover-side recessed portion 21 of the motor 20, a mover-side groove portion 22b is formed on a mover-side projection portion 22, and the stator-side groove portion 12b and the mover-side groove portion 22b can house the mover-side projection piece 21b and the stator-side projection piece 11b opposed to each other with the wire 30.SELECTED DRAWING: Figure 6

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator that generates vibration by utilizing heat-induced shrinkage of a shape memory alloy, and more particularly, to an actuator in which a recess and a protrusion are formed on a stator and a moving member to prevent a wire of the shape memory alloy from protruding. About.

  For example, there is a mobile terminal such as a smart phone, a so-called VR (virtual reality) game device, or the like, on which an actuator (vibration device) for transmitting vibration to a user is mounted. This type of actuator as a user interface using the tactile sensation of the skin is small and lightweight, and a large acceleration can give a strong tactile sensation to the user.

  As this type of actuator, there is an actuator that uses a shape memory alloy and generates vibration by moving the moving member away from and closer to the stator.

  For example, Patent Documents 1 to 4 exist as the above actuator.

  Patent Documents 1 to 4 have a wire made of a conductive shape memory alloy, and cause a movable member to move away from a stator or to an original position by the heat generated by energization and the expansion and contraction of the wire by cooling when not energized. The device is configured to generate a vibration by returning to give a user a click feeling or the like at the time of operating the touch panel.

Patent No. 6046980 Patent No. 5787120 JP 2018-21466 A JP 2018-21468 A

  However, actuators have become smaller and thinner, and the areas of the stator and the mover that hold the wire have also become smaller. For this reason, there are problems in that it is difficult to assemble the actuator and that the wire easily falls off between the stator and the mover. In particular, when an external force is applied from the side surface of the stator or the mover, a displacement occurs between the stator and the mover, and the wire may fall off from the displacement.

  On the other hand, in Patent Literature 1, a groove is formed in the moving element side projection of the moving element. In Patent Document 2, ribs are formed on both sides of the stator. In Patent Literature 3, a groove is formed in each protrusion of the stator and the mover. In Patent Literature 4, walls are formed on both sides in the width direction of each protrusion by sandwiching both side surfaces of the stator and the mover with outer shells, respectively.

  As described above, in Patent Documents 1, 3, and 4, the grooves are formed in the protrusions of the stator or the movable element to prevent the wire from falling off. Not something you can do. Further, in Patent Literatures 2 and 4, there is a problem that the size of the actuator is increased because the ribs and the outer shell are provided on both side surfaces of the stator or the movable member.

  The present invention has been proposed in view of the above, and it is an object of the present invention to provide an actuator capable of suppressing displacement between a stator and a moving element and preventing a wire from falling off. Is to do.

  In order to achieve the above object, an actuator according to the present invention includes a stator, a mover opposed to the stator, and provided so as to be able to approach and separate from the stator, and a shape memory alloy between the stator. An actuator provided with a contractible and extensible wire, comprising: a stator, a stator-side protrusion and a stator-side recess are alternately arranged in one direction of the stator on a surface facing the mover. The mover is formed such that a mover-side recessed portion on a surface facing the stator protrusion and a mover-side protrusion on a surface facing the stator-side recessed portion are provided in one direction of the mover. The stator-side depressions are formed alternately, and the stator-side projections projecting from the bottom surface are formed in the stator-side depressions, and the mover-side projections projecting from the bottom surface are formed in the mover-side depressions. The stator-side protrusions, together with the wires, are opposed to the transfer. A groove capable of accommodating a stator-side protruding piece is formed, and a groove capable of accommodating the opposed stator-side protruding piece is formed on the mover-side protruding part together with the wire. .

  In the actuator, the stator and the mover are located between the top surface of the stator-side protrusion and the bottom surface of the mover-side groove, even when the mover and the stator are closest to each other, and A gap may be formed between the top surface of the mover-side protruding piece and the stator-side groove.

  Further, in the actuator, the bottom surfaces of the stator-side recess and the mover-side recess, and the top surfaces of the stator-side protrusion and the mover-side protrusion each have an arc shape having a first curvature. The top surfaces of the stator-side protruding piece and the mover-side protruding piece, and the bottom surfaces of the stator-side groove portion and the mover-side groove portion each have an arc shape having a second curvature smaller than the first curvature. You may not.

  In the actuator, the stator and the mover may be made of resin.

  As described above, according to the present invention, it is possible to suppress the displacement between the stator and the movable element and prevent the wire from falling off.

FIG. 4 is an explanatory view showing an operation principle of the present invention, in which a wire made of a shape memory alloy is cooled. It is explanatory drawing which shows the state which the wire shrinks by the heat | fever and pushes up a moving element, which is the operating principle of the same invention. FIG. 4 is an explanatory view showing the operation principle of the present invention, in which a current to the wire is cut off after the wire is shrunk by heat. FIG. 4 is an explanatory view showing the operation principle of the present invention, in which the wire is cooled by the stator and the movable element returns to the original position by the urging force acting on the movable element. It is a top view of the actuator concerning one embodiment of the present invention. It is a perspective view of the actuator concerning one embodiment of the present invention. 1 is an exploded perspective view of an actuator according to one embodiment of the present invention. It is an expansion perspective view showing the upper surface of a stator. It is an expansion perspective view which shows the lower surface of a moving element. (A) is a sectional view taken along line II of FIG. 5 and (b) is a sectional view taken along line II-II of FIG. 5. 10A is an enlarged view of a main part of FIG. 10A and FIG. 10B is an enlarged view of a main part of FIG.

  First, prior to the embodiment of the present invention, the operation principle of the actuator used in the present embodiment will be described with reference to FIGS.

  In FIG. 1, reference numeral 1 denotes a stator which is one of the main members constituting the actuator, and 2 denotes a moving element. Reference numeral 3 denotes a wire made of a shape memory alloy, and is disposed between the stator 1 and the moving element 2. 4 is an electric wire connected to the wire 3 made of the shape memory alloy, 5 is a power source, 6 is a power switch for turning on and off, and when turned on, the wire 3 made of the shape memory alloy is energized. FIG. 1 shows a state in which the switch 6 is off, the current is off, and the moving element 2 is positioned on the stator 1 side.

  FIG. 2 shows a state where the switch 6 is turned on and the wire 3 is energized. When a current flows through the wire 3 and the wire 3 generates heat, the wire 3 shrinks, and the wire 3 becomes taut. As a result, a thrust is generated in a direction to move the moving member 2 away from the stator 1 as indicated by an arrow.

  When the switch 6 is turned off, no current flows through the wire 3 and the wire 3 is cooled by the stator 1. FIG. 3 shows this state. When cooled, the urging force acts on the mover 2 in the direction of the arrow as shown in FIG. 4, whereby the wire 3 is extended, and the mover 2 is again positioned on the stator 1 side as shown by the arrow and returns to its original state. Becomes Vibration is generated by repeating these series of operations.

  5 is a front view of the actuator according to one embodiment of the present invention, FIG. 6 is a perspective view, FIG. 7 is an exploded perspective view, FIG. 8 is an enlarged perspective view showing the upper surface of the moving element, and FIG. FIG. 10A is a cross-sectional view taken along the line II of FIG. 5, FIG. 10B is a cross-sectional view taken along the line II-II of FIG. 5, and FIG. 10A is an enlarged view of a main part and FIG. 10B is an enlarged view of a main part of FIG.

  First, the actuator A of the present embodiment will be described with reference to FIG. 5 showing a front view, FIG. 6 showing a perspective view, and FIG. 7 showing an exploded perspective view. In the figure, reference numeral 10 denotes a stator made of an insulating heat conductor, which is made of a resin having heat dissipation. Reference numeral 20 denotes a movable element which is disposed above the stator 10 in a state shown in the drawing, and a wire 30 made of a shape memory alloy is provided therebetween. This corresponds to the stator 1, the mover 2, and the wire 3 shown in FIGS.

  It is preferable to use an insulating heat-radiating resin or the like as a material forming the stator 10 and the moving element 20. In particular, polyphenylene sulfide (hereinafter, PPS), which is a thermoplastic resin having high heat resistance, excellent wear resistance, and excellent dimensional stability, is preferably used as the heat radiation resin. Further, when a heat-radiating resin is used for the stator 10 and the moving member 20, if PPS is used by dispersing fine particles of a heat-conductive filler for improving heat conductivity, the heat-radiating property of the shape memory alloy is further improved and the actuator A Is effective in improving the repetition rate of the reaction. As long as molding is possible, the stator 10 and the moving element 20 may be made of a metal material such as aluminum having good heat dissipation and subjected to insulation treatment.

  As the heat dissipating resin, a polyamide synthetic resin may be used in addition to the PPS.

  The stator 10 has a substantially rectangular parallelepiped shape elongated in the horizontal direction. In addition, the upper surface of the stator 10 (the surface facing the moving element 20) has a wavy portion in which stator-side depressions 11 and stator-side protrusions 12 are alternately formed in the longitudinal direction. In this embodiment, six stator-side depressions 11 and five stator-side projections 12 are formed, but the number of the stator-side depressions 11 and the stator-side projections 12 is not limited thereto. It is not something that can be done.

  As shown in detail in FIG. 8, the stator-side recessed portion 11 is formed such that the bottom surface 11 a is curved at a first curvature in the longitudinal direction of the stator 10. Further, the stator-side recessed portion 11 is formed with a stator-side protruding piece 11b protruding from the bottom surface 11a at the center in the width direction (transverse direction). The top surface 11bt of the stator-side protruding piece 11b has an arc shape that is curved in the longitudinal direction of the stator 10 with a second curvature smaller than the first curvature (that is, having a large radius of curvature).

  In addition, the stator-side protrusion 12 has a top surface 12 a formed in an arc shape curved at a first curvature in the longitudinal direction of the stator 10. Further, the stator-side protrusion 12 has a stator-side groove 12b that is recessed from the top surface 12a at the center in the width direction (transverse direction). The bottom surface 12bb of the stator side groove portion 12b has an arc shape curved at the second curvature in the longitudinal direction of the stator 10.

  As described above, in the wavy portion of the stator 10, the stator-side protruding pieces 11 b and the stator-side grooves 12 b are alternately formed at the center in the width direction, and the bottom surface 11 a of the stator-side depression 11 and the stator-side protrusion are formed. A wave shape having a smaller (slower) curvature than the top surface 12a of the portion 12 is formed. The corners of the stator-side protruding piece 11b and the stator-side groove 12b are R-chamfered and R-grooved.

  The moving element 20 is also an insulating heat conductor and is made of a resin having heat dissipation. The moving element 20 also has a substantially rectangular parallelepiped shape elongated in the horizontal direction. The upper surface (the surface facing the stator 10) of the movable element 20 has a wavy portion in which the movable element-side depression 21 and the movable element-side protrusion 22 are alternately formed in the longitudinal direction. In the present embodiment, five sliders 21 and six protrusions 22 are formed. However, the number of the recesses and the protrusions is not limited thereto. is not.

  As shown in detail in FIG. 9, the mover-side concave portion 21 is formed in an arc shape whose bottom surface 21 a is curved at a first curvature in the longitudinal direction of the mover 20. Further, the movable element side recessed portion 21 is formed with a movable element side protruding piece 21b projecting from the bottom surface 21a at the center in the width direction (transverse direction). The top surface 21bt of the moving element-side protruding piece 21b has an arc shape curved at the second curvature in the longitudinal direction of the moving element 20.

  The top side 22 a of the mover-side projection 22 is formed in an arc shape curved at a first curvature in the longitudinal direction of the mover 20. Further, the slider-side protrusion 22 has a slider-side groove 22b recessed from the top surface 22a at the center in the width direction (transverse direction). The bottom surface 22bb of the mover-side groove 22b has an arc shape curved at the second curvature in the longitudinal direction of the mover 20.

  As described above, in the wavy portion of the movable member 20, the movable member-side protruding pieces 21b and the movable member-side groove portions 22b are alternately formed at the center in the width direction, and the bottom surface 21a of the movable member-side recessed portion 21 and the movable member-side protrusion are formed. A wave shape having a smaller (slower) curvature than the top surface 22a of the portion 22 is formed. The corners of the slider-side protruding piece 21b and the slider-side groove 22b are R-chamfered and R-grooved.

  The corrugated portion of the stator 10 and the corrugated portion of the mover 2 can engage with each other with the wire 30 interposed therebetween. Specifically, the mover-side protrusion 22 engages with the stator-side recess 11, and the stator-side protrusion 12 engages with the mover-side recess 21. Further, as shown in FIG. 10A, the stator-side groove 12b of the stator-side protrusion 12 can accommodate the mover-side protruding piece 21b of the mover-side recess 21 together with the wire 30. As shown in (b), the mover-side groove 22b of the mover-side protrusion 22 can accommodate the stator-side protruding piece 11b of the stator-side recess 11 together with the wire 30.

  More specifically, as shown in FIG. 11A, when the stator 10 and the movable element 20 are closest to each other, the top surface 12a of the stator-side projection 12 and the bottom surface 21a of the movable element-side recessed part 21 On the other hand, there is a gap between the stator-side groove 12b and the mover-side protruding piece 21b, and the wire 30 is arranged in the gap. Also, as shown in FIG. 11B, when the stator 10 and the mover 20 are closest to each other, the top surface 22a of the mover-side protrusion 22 and the bottom surface 11a of the stator-side recess 11 are in contact with each other. On the other hand, there is a gap between the mover-side groove 22b and the stator-side protruding piece 11b, and the wire 30 is disposed in the gap.

  These gaps are at least the distance between the bottom surface 12bb of the stator-side groove portion 12b and the top surface 21bt of the mover-side protruding piece 21b, and the bottom surface 22bb of the mover-side groove portion 22b and the top surface 11bt of the stator-side protruding piece 11b. Should be larger than the diameter of the wire 30.

  Further, the depth of the stator side groove portion 12b and the mover side groove portion 22b and the height of the stator side protrusion piece 11b and the mover side protrusion piece 21b are determined by the actuator A when the stator 10 and the mover 20 are closest to each other. It is necessary to add a dimension larger than the amplitude of the actuator A in addition to the height at which the stator 10 and the mover 20 cannot be disengaged by an external force from the lateral side of the actuator A. That is, it is preferable that the protruding pieces 11b and 21b be accommodated in the respective groove portions 12b and 22b even when the movable member 20 is most separated from the stator 10. As a result, even when the actuator A vibrates, the projections 11b and 21b always close the openings of the grooves 12b and 22b, so that the wire 30 can be more reliably prevented from falling off.

  If the distance between the side wall of each groove 12b, 22b and the side wall of each protruding piece 11b, 21b is smaller than the diameter of the wire 30, the wire 30 will not fall out of the side wall of each groove 12b, 22b, which is more preferable. .

  The wire 30 is made of an alloy having a shape memory alloy effect such as a nickel-titanium alloy. As shown in FIG. 7 (see FIGS. 8 and 9 for each of the protruding pieces 11b and 21b and each of the grooves 12b and 22b), the wire 30 is connected to each of the protruding pieces 11b of the stator 10 and the mover 20 in the non-energized state. , 21b and the grooves formed by the grooves 12b, 22b, and are arranged so as to be located between the projecting pieces 11b, 21b and the grooves 12b, 22b.

  One end of the wire 30 is attached via a terminal section 40 on the terminal block 13 side formed at one longitudinal end of the stator 10. Similarly, the other end of the wire 30 is attached via a terminal portion 40 on a terminal block 14 formed on the other end in the longitudinal direction of the stator 10.

  Reference numerals 41 to 43 denote wire attachment portions provided on one end side of the terminal portion 40. The wire attachment portions 41 to 43 have, for example, first to third divided structures, and each of the attachment portions 41 to 43 has a groove b through which the wire 30 is inserted and fixed.

  Of these, the first and third mounting portions 41 and 43 are formed at the same position, and the position of the central second mounting portion 42 is shifted in the width direction. This allows the wire 3 to be easily fixed by attaching it in a crank shape and caulking, and to prevent the wire 3 from being loosened when it expands and contracts.

  On the other end side of the terminal portion 40, a terminal base portion 44 fixed to the terminal blocks 13 and 14 is formed. The terminal base 44 has two holes d for screw insertion, and an electric wire connection hole 45 for connection through an electric wire (not shown).

  Reference numeral 50 denotes a leaf spring 50 provided on the upper surface of the terminal section 40. The leaf spring 50 is bent in a substantially Z shape as a whole, and is attached to the upper surface of the terminal portion 40.

  The leaf spring 50 has a leaf spring base 51 attached to the terminal base 44 of the terminal part 40, a leaf spring intermediate part 52 rising from one end of the leaf spring base 51, and an acute angle of 90 ° from the leaf spring intermediate part 52. And a leaf spring pressing portion 53 extending to bend. The distal end 53a of the leaf spring pressing portion 53 is slightly bent upward (opposite to the surface to be pressed).

  The plate spring base 51 also has two holes c through which the screws 60 are inserted. Similarly, two screw holes e are formed in the terminal blocks 13 and 14 of the stator 10, respectively. The screw 60 is inserted into the hole c of the leaf spring 50, the hole d of the terminal part 40, and the hole e of the terminal blocks 13, 14, and the screw hole f of the screw fixing part 61 located on the lower surface of the terminal blocks 13, 14. Is screwed on.

  At both ends in the longitudinal direction of the upper surface of the mover 20, leaf spring support grooves 23 and 24 that are recessed along the tip shape of the tip portion 53a are formed. Each leaf spring 50 engages with the leaf spring support grooves 23 and 24 of the movable member 20 at the distal end side of the leaf spring pressing portion 53, and applies an urging force for pressing the movable member 20 toward the stator 10.

  Reference numerals 15 and 16 denote wire guides formed at upper portions in the longitudinal direction of the terminal blocks 13 and 14 of the stator 10. The wire guides 15 and 16 are composed of a pair of protrusions, and a straight portion of the wire 30 is inserted and guided between the protrusions, and is drawn out to the wire attachment portions 41 to 43.

  In assembling, first, the terminal portion 40 is provided on the terminal blocks 13 and 14 of the stator 10.

  The wire 30 is cut into a predetermined length in advance, and is inserted into each groove b of the wire attachment portions 41 to 43 at both ends thereof and caulked. Further, the wire 30 is placed on the protrusions of the wire guides 15 and 16 of the stator 10 and the stator groove 12b, whereby positioning in the width direction is performed and arranged.

  Subsequently, the movable member 20 is mounted on the stator 10 so that the corrugated portion of the stator 10 and the corrugated portion of the movable member 20 are engaged so that the wire 30 is sandwiched between the stator 10 and the movable member 20. . Thereby, the wire 30 is arranged between the stator-side protruding piece 11b and the mover-side groove 22b and between the stator-side groove 12b and the mover-side protruding piece 21b.

  Next, the leaf spring holding portions 53 are engaged with the leaf spring support grooves 23 and 24 of the movable member 20, the leaf spring base 51 is disposed on the terminal base 44 of the terminal portion 40, and the screws 60 are provided with the respective holes c and d. , E. Each member is integrated by screwing the tip of the screw 60 into the screw hole f of the screw fixing portion 61.

  In operation, when the wire 30 is energized and generates heat, the wire 30 contracts, and the thrust causes the mover 20 to move away from the stator 10 against the urging force of the leaf spring 50. When the wire 30 is de-energized, the wire 30 is cooled via the stator 10, the mover 20, etc., and extends to the length before energization, and the mover 2 instantaneously moves to the position on the stator 1 side by the urging force of the leaf spring 50. Return to

  The actuator A of the present embodiment thus configured has a stator-side protruding piece 11b formed in a stator-side recess 11 of a stator 10 and a stator-side groove 12b formed in a stator-side protrusion 12. The main feature is that a movable element side protruding piece 21b is formed in the movable element side recess 21 of the movable element 20 and a movable element side groove 22b is formed in the movable element side projection 22.

  As a result, the wire 30 is accommodated in the stator-side groove 12b and the mover-side groove 22b, and the openings of the stator-side groove 12b and the mover-side groove 22b correspond to the corresponding stator-side protrusions 11b and mover-side protrusions. Since the wires 30 are closed, the wires 30 are prevented from dropping from the stator 10 and the moving member 20. This is because even when a force is applied to the stator 10 or the mover 20 from outside, between the stator-side groove 12b and the mover-side groove 22b and the stator-side protrusion 11b and the mover-side protrusion 21b. Since the movement in the width direction is restricted, the displacement between the stator 10 and the mover 20 is suppressed, and the wire 30 is prevented from falling off.

  Also, the top surface 11bt, 21bt of the stator-side protruding piece 11b and the mover-side protruding piece 21b and the bottom surface 12bb, 22bb of the stator-side groove portion 12b and the mover-side groove portion 22b are closest to the stator 10 and the mover 20. Even when the external force is applied from the short side surface of the actuator A in a state where the stator and the mover are closest to each other, an extra force is applied to the wire 30 in a state where the stator and the mover are closest to each other. In addition, the wire 30 can be more reliably prevented from falling off.

  In addition, the stator and the movable member are made of a heat-radiating resin, and are formed by the corrugated shape formed by the stator-side protruding pieces 11b and the stator-side groove portions 12b, and by the mover-side protruding pieces 21b and the mover-side groove portions 22b. By forming the corrugated shape by the injection molding method, each protruding piece and each groove can be easily formed even on a miniaturized and thinned stator and movable element, so that mass productivity is good.

  The embodiment of the present invention has been described above, but aspects of the present invention are not limited to this embodiment.

  Although the actuator A of the above embodiment uses only one wire 30 of the shape memory alloy, the number of wires is not limited to this, and a plurality of wires may be used.

  Further, in the above embodiment, both ends of the wire 30 are attached to the stator 10 by the terminal portions 40, but the attachment structure of the wire 30 is not limited thereto, and may be attached by other means.

  Further, in the above embodiment, the movable element 20 may be attached to the stator by pressing the movable element 20 against the stator 10 with the leaf spring 50 made of a thin leaf spring.

Reference Signs List A Actuator 1, stator 2 mover 3 wire 4 electric wire 5 power supply 6 power switch 10 stator 11 stator-side recess 11a stator-side recess bottom 11b stator-side protruding piece 11bt Stator-side protruding piece top 12 fixed Child-side protrusion 12a Stator-side protrusion top 12b Stator-side groove 12bb Stator-side groove bottom 13,14 Terminal block 15,16 Wire guide 20 Mover 21 Mover-side depression 21a Mover-side depression bottom 21b Projector-side projecting piece 21bt Projector-side projecting piece top surface 22 Projector-side projecting portion 22a Projector-side projecting portion top surface 22b Projector-side groove portion 22bb Projector-side groove bottom surface 23, 24 Leaf spring support groove 30 Wire 40 Terminal Parts 41, 42, 43 Wire attachment part 44 Terminal base 45 Wire connection hole 50 Leaf spring 51 Leaf spring base 52 Leaf spring middle part 53 Leaf spring Pressing part 53a Tip part 60 Screw 61 Screw fixing part b Groove c, d, e, hole f Screw hole

Claims (4)

An actuator comprising a stator, a movable member opposed to the stator and provided so as to be able to approach and separate from the stator, and a contractible and extendable wire made of a shape memory alloy between the stator and the movable member. ,
The stator has a stator-side protrusion and a stator-side recess formed alternately in one direction of the stator on a surface facing the mover,
The mover has a mover-side recess on a surface facing the stator protrusion and a mover-side protrusion formed alternately in one direction of the mover on a surface facing the stator recess. And
A stator-side protruding piece projecting from the bottom surface is formed in the stator-side recess,
A moving element-side protruding piece protruding from the bottom surface is formed in the moving element-side concave portion,
The stator-side protrusion has, along with the wire, a groove that can accommodate the opposing mover-side protrusion.
An actuator, wherein a groove capable of accommodating the opposed stator-side protruding piece together with the wire is formed in the mover-side protrusion.   The stator and the mover, even when the mover and the stator are closest, between the top surface of the stator-side protruding piece and the bottom surface of the mover-side groove, and the mover side The actuator according to claim 1, wherein a gap is formed between a top surface of the protruding piece and the stator-side groove. The bottom surface of the stator-side recess and the mover-side recess, and the top surface of the stator-side protrusion and the mover-side protrusion each have an arc shape having a first curvature,
The top surfaces of the stator-side protruding piece and the mover-side protruding piece, and the bottom surfaces of the stator-side groove portion and the mover-side groove portion each form an arc having a second curvature smaller than the first curvature. The actuator according to claim 1, wherein the actuator is provided. 4. The actuator according to claim 1, wherein the stator and the mover are made of a heat-radiating resin. 5.

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