JP2010203312A - Drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive device capable of stably fixing SMA (Shape-Memory Alloy) and connecting a current-carrying member without blocking miniaturization of a device and without affecting the performance of SMA. <P>SOLUTION: The drive device equipped with string shape shape-memory alloy as a drive source includes: a base member which is a base of the drive device; a bar shape terminal made of metal passing through the base member, fixed on the base member, and caulked at one end side to hold the shape-memory alloy; and a terminal member electrically connected to another end side of the bar shape terminal. The terminal member includes a press-fit part having another end side of the bar shape terminal press-fitted to one end side of the terminal member and abutting on the bar shape terminal, and a current-carrying connection part having the current-carrying member connected to another end side of the terminal member for supplying current to the shape-memory alloy. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive device, and more particularly to a drive device provided with a shape memory alloy.

  In recent years, attempts have been made to use actuators provided with shape memory alloys (hereinafter also referred to as SMA) in various drive devices. SMA is represented by an alloy of titanium and nickel or the like, and is an alloy having a property of being restored to its original shape by martensitic transformation even when it is deformed at a temperature called a transformation point or lower and heated above that temperature. Usually, SMA is formed in a string-like form, and can be operated as an actuator by expanding and contracting in the length direction by energization heating control.

  Since such a SMA has a thin wire diameter of several tens of μm, it is possible to reduce the size of the device provided with the SMA actuator, and mounting on various devices is being studied.

  By the way, such a string-like SMA is normally supported by a base member provided on a frame, a casing, or the like via a fixing member that fixes both ends of the SMA in a state of being laid on a driven member. . In addition, a lead wire for energizing the SMA and a connection terminal for connecting an energizing member such as a flexible substrate are provided around the fixing member and the fixing member.

  For example, the SMA is fixed by being pressed into a hole provided in the base member together with a ball or a wedge, and a lead wire for energizing the SMA is connected to a connection terminal provided near the hole of the base member by soldering. A configuration for connection is known (see Patent Document 1).

  In addition, the SMA is clamped and fixed to the holding portion formed by bending the plate-like member, and the SMA is energized between the ring-shaped washer member and the base member provided in the holding portion. A method is known in which a lead wire is sandwiched and fixed with screws (see Patent Document 2).

JP 2002-98911 A JP 2006-189036 A

  However, in the method disclosed in Patent Document 1, since the hole of the base member to which the SMA is fixed and the connection terminal to which the lead is soldered are arranged close to each other, the heat conduction during the soldering operation is performed. There is a risk of affecting the performance of the SMA.

  Further, in the method disclosed in Patent Document 2, a so-called lug plate configuration in which a holding portion to which an SMA is clamped and crimped and a washer member to which a lead wire is connected is integrated in a planar shape. is there. That is, the connection position of the lead wire is limited to the vicinity of the SMA pinching portion of the lug plate. For this reason, it is difficult to easily handle the current-carrying member such as a lead wire in a limited space of the device in which the drive device is mounted, and there is a problem in that downsizing of the device is hindered. .

  The present invention has been made in view of the above problems, and can stably fix the SMA and connect the current-carrying member without inhibiting the downsizing of the apparatus and without affecting the performance of the SMA. An object of the present invention is to provide a drive device capable of satisfying the requirements.

  The above object is achieved by the invention described in any one of 1 to 11 below.

1. In a drive device provided with a string-like shape memory alloy as a drive source,
A base member serving as a base of the driving device;
A bar-like terminal made of a metal that penetrates the base member and is fixed to the base member, and which is crimped at one end to sandwich the shape memory alloy;
A terminal member electrically connected to the other end side of the rod-shaped terminal,
The terminal member is
A press-fitting portion in which the other end side of the rod-like terminal is press-fitted into one end side of the terminal member and comes into contact with the rod-like terminal;
A drive device comprising: a current-carrying connection portion to which a current-carrying member for supplying a current to the shape memory alloy is connected to the other end side of the terminal member, and being held by a predetermined member .

2. Holding the terminal member and having a holding member fixed to the base member;
2. The driving apparatus according to claim 1, wherein the terminal member is insert-molded and held by the holding member in a form in which the press-fitting portion and the energization connection portion of the terminal member are exposed.

3. The press-fitting portion of the terminal member has an opening into which the other end side of the rod-shaped terminal is press-fitted,
At the periphery of the opening, at least two beam portions that contact the rod-shaped terminal are formed by press-fitting the other end of the rod-shaped terminal from the periphery of the opening toward the center of the opening. 3. The drive device according to 1 or 2, wherein the drive device is provided.

  4). 4. The drive device according to 3 above, wherein the at least two beam portions of the press-fit portion are arranged so as to abut at equal intervals in the circumferential direction of the cross section of the rod-shaped terminal.

  5. The at least two beam portions of the press-fitting portion are arranged so that a vector sum of pressure applied to the rod-shaped terminal by the at least two beam portions is substantially zero. Drive device.

  6). The said press-fit part of the said terminal member is formed so that a displacement is possible with respect to the site | part currently shape | molded by the said holding member of this rod-shaped terminal, The said any one of 3-5 characterized by the above-mentioned. Drive device.

  7). 7. The driving device according to any one of 1 to 6, wherein the rod-shaped terminal is a metal having a Young's modulus of 50 GPa or more and 250 GPa or less.

  8). 8. The drive device according to 7, wherein the rod-shaped terminal is made of a copper-based metal.

  9. 8. The drive device according to 7, wherein the rod-shaped terminal is made of SUS steel.

  10. 10. The driving apparatus according to any one of 1 to 9, wherein a caulking portion for sandwiching the shape memory alloy is formed on a side surface or an end surface on one end side of the rod-shaped terminal.

  11. 11. The driving device according to any one of 1 to 10, wherein a cross section in the radial direction of the rod-shaped terminal is formed in a circular shape or a polygonal shape.

  According to the present invention, one end of a bar-like terminal fixed through the base member is crimped, the SMA is sandwiched, and the other end is press-fitted into a terminal member to which an energizing member for supplying current to the SMA is connected. Thus, the terminal member is brought into contact with the rod-shaped terminal. In this case, since a predetermined thickness is required for the base member to hold and hold the rod-shaped terminal with sufficient strength, the crimping portion on one end side where the SMA of the rod-shaped terminal is fixed by crimping and the terminal member At least the thickness of the base member is secured as the distance from the other end with which the press-fitting portion abuts. Furthermore, a current-carrying member is connected to the rod-shaped terminal via a terminal member.

  As a result, when the current-carrying member is connected to the terminal member by, for example, soldering, a sufficient distance can be ensured that the heat conduction during the soldering operation does not affect the performance of the SMA. Further, there is heat dissipation to a base member for fixing the rod-shaped terminal and a predetermined member (for example, a holding member) for holding the terminal member. As a result, heat conduction to the SMA can be suppressed, and deterioration of the SMA performance can be prevented.

  Further, the contact pressure when the terminal member comes into contact with the rod-shaped terminal may be sufficient to ensure electrical continuity with the rod-shaped terminal. Such a contact pressure can be determined by the positional relationship between the position of the rod-shaped terminal and the press-fitting portion of the terminal member, and the shape and material of the press-fitting portion of the terminal member. Therefore, a large load due to the contact of the terminal member is not hung on the rod-shaped terminal. For this reason, when connecting an electricity supply member to a terminal member, the load over a rod-shaped terminal in the case of a connection operation can be suppressed. As a result, the influence on the installation tension of SMA can be suppressed.

  Further, the position of the energization connecting portion to which the energization member of the terminal member is connected is not limited to the position of the rod-shaped terminal where the SMA is sandwiched, and a desired position considering the winding of the energization member such as a lead wire. Can be provided. As a result, in a limited space of the device on which the drive device is mounted, it is possible to easily handle the current-carrying member such as a lead wire and to reduce the size of the device.

  As a result, the SMA can be stably fixed and the current-carrying member can be connected without hindering downsizing of the apparatus and without affecting the performance of the SMA.

It is a schematic diagram which shows schematic structure of the lens drive device concerning embodiment of this invention. It is a schematic diagram which shows the shape of the crimping part of an SMA fixing member. It is a schematic diagram which shows the shape of an SMA fixing member. It is a schematic diagram which shows the structure around a holding member and a terminal member. It is a schematic diagram explaining the press injection method to the terminal member of a SMA fixing member. It is a schematic diagram of the structure of the press fit part of a terminal member. It is a schematic diagram which shows the shape by another example of the beam part of a press-fit part. It is a block diagram which shows schematic structure of a control system.

  Embodiments of a drive device according to the present invention will be described below with reference to the drawings. In addition, although this invention is demonstrated based on embodiment of illustration, this invention is not limited to this embodiment.

  First, the configuration of a lens driving device which is one of the typical embodiments of the driving device according to the present invention will be described with reference to FIG. FIG. 1A is a schematic plan view showing the appearance of the lens driving device 1, FIG. 1B is a schematic front view showing an aspect when the SMA 104 is not energized, and FIG. It is a front schematic diagram which shows the aspect when it supplies with electricity.

  As shown in FIGS. 1A and 1B, the lens driving device 1 includes a base member 101, a hinge 102, a driving lever 103, an SMA 104, a coil spring 105, a leaf spring 106, a lens barrel 111, and a lens 112. , SMA fixing members 121 and 122, holding member 151, terminal members 161 and 162, and the like.

  As shown in FIG. 1A and FIG. 1B, two rod-shaped SMA fixing members 121 and 122 made of metal are fixed in a manner that penetrates the base member 101. The SMA fixing members 121 and 122 correspond to the rod-shaped terminals of the present invention.

  Both ends of the SMA 104 are fixed to the upper ends of the SMA fixing members 121 and 122 by caulking, respectively. In addition, the lower end side is press-fitted into the terminal members 161 and 162 to which a current supply member (not shown) for supplying current to the SMA 104 is connected, so that the terminal members 161 and 162 are in contact with each other. The terminal members 161 and 162 are held by a holding member 151, and the holding member 151 is fixed to the base member 101. The fixing method by caulking of the SMA 104 and the details of the terminal members 161 and 162 will be described later.

  The SMA 104 has, for example, a wire shape with a wire diameter of about several tens of μm. As shown in FIGS. 1 (a) and 1 (b), the SMA 104 is hooked on the locking portion 103a of the drive lever 103, and both ends thereof are base members. The SMA fixing members 121 and 122 that also serve as the electrodes provided in 101 are fixed by caulking, respectively.

  As the current-carrying member, a commonly used metal thin plate, wire (lead wire), or flexible substrate can be used.

  The drive lever 103 is supported by a hinge 102 provided on the base member 101 so as to be rotatable in the direction of arrow P with the hinge 102 as a fulcrum.

  The lens barrel 111 including the lens 112 is held by the tip portions 103b and 103c of the drive lever 103 by two contact members 113a and 113b provided on the lens barrel 111. At the bottom of the lens barrel 111, an image sensor such as a CCD (Charge Coupled Device) or a CMOS sensor (not shown) that photoelectrically converts the subject optical image formed by the lens 112 to generate an image signal is provided. Yes. The lens barrel 111 is kept parallel by leaf springs 106 provided on the upper and lower surfaces thereof.

  One end of the coil spring 105 is fixed to the cover 107 of the housing, the other end abuts on the upper surface of the lens barrel 111, and the lens barrel 111 is urged in the direction of the arrow Y2, thereby causing the SMA 104 to move to the drive lever. A tension is applied in the direction of the arrow X2 via 103. On the other hand, the SMA 104 is given a stress (reference stress) as a desired reference in the direction of the arrow X1 when it is installed. When the lens barrel 111 is not in operation, the lens barrel 111 is stopped at a position (initial position) where the reference stress applied to the SMA 104 and the tension by the coil spring 105 are balanced.

  In the state of FIG. 1B, when a current is passed through the SMA 104 from the SMA fixing member 121 to the SMA fixing member 122 via the terminal members 161 and 162, the SMA 104 generates Joule heat due to its own resistance value. Then, the generated heat causes the SMA 104 to undergo a phase transformation, and the elastic modulus becomes a relatively high state, and shrinks in the direction of the arrow X1 in an attempt to return to the stored length state (original state). At this time, the force that the SMA 104 tries to contract overcomes the predetermined tension that the coil spring 105 applies to the SMA 104 via the drive lever 103. As a result, the lens barrel 111 is driven toward the arrow Y1. FIG. 1C shows a state after the lens barrel 111 is driven in the direction of the arrow Y1.

  Further, when the current flowing through the SMA 104 is interrupted in the state of FIG. 1C, the SMA 104 undergoes a phase transformation due to cooling by heat radiation, and the elastic coefficient becomes relatively low. Then, a predetermined tension is applied to the SMA 104 from the coil spring 105 via the drive lever 103, and the SMA 104 is in a state of extending. As a result, the lens barrel 111 is driven in the direction of the arrow Y2, and the state returns to the state of FIG. In this manner, the operation of driving the lens barrel 111 in the directions of the arrows Y1 and Y2 can be appropriately repeated by extending and contracting the SMA 104 by heating and cooling.

  Next, the SMA fixing members 121 and 122 will be described with reference to FIGS. Since the SMA fixing member 121 and the SMA fixing member 122 have the same shape, only the SMA fixing member 121 will be described in the following description. 2A is a schematic front view showing the shape of an example of the caulking portion of the SMA fixing member 121. FIGS. 2B to 2D are diagrams showing the shape of another example of the caulking portion of the SMA fixing portion 121. FIG. FIGS. 2 (e) and 2 (f) are schematic diagrams showing shapes according to other examples in which the caulking portion of the SMA fixing portion 121 is seen from the front obliquely forward. FIG. 3A is a schematic perspective view showing the shape of one example of the SMA fixing member 121, and FIG. 3B is a schematic perspective view showing the shape of another example.

  As shown in FIG. 2A, a V-shaped groove 121v is formed around the side surface of the SMA fixing member 121, and the SMA 104 is sandwiched between the grooves 121v. When a load is applied to the end surface 121a of the SMA fixing member 121 in the Y2 direction, the end portion 121b that is the caulking portion of the SMA fixing member 121 is deformed, and the SMA 104 is fixed by crimping (caulking). Note that the diameter d1 of the end portion 121b is made smaller than the diameter d2 of the non-deformed portion 121c in order to prevent disconnection of the SMA 104 due to the end portion 121b deformed by caulking covering the non-deformed portion 121c. Further, as will be described later, when the SMA fixing member 121 is fixed to the base member 101 by press-fitting, there is a risk of deformation when the end 121b of the SMA fixing member 121 is pressed, so that the non-deforming portion 121c is pressed to press-fit. In this case, similarly, the diameter d1 of the end 121b is made smaller than the diameter d2 of the non-deformed portion 121c so that the end 121b is not caught in the press-fitting hole of the base member 101.

  Here, the shape of another example of the caulking portion is shown in FIG. As shown in FIG. 2B, the groove 121v may be formed in a V shape in a part of the side surface of the end 121b of the SMA fixing member 121.

  Moreover, the shape by the another example of a crimping part is shown in FIG.2 (c). As shown in FIG. 2 (c), the groove 121 v may be formed on the end surface 121 a of the SMA fixing member 121. In this case, the SMA fixing member 121 is caulked by covering the end portion 121b of the SMA fixing member 121 with the crimping jig 5 having a taper 5a formed on the inner surface shown in FIG. Further, as shown in FIG. 2D, a taper 121 t may be formed at the end 121 b of the SMA fixing member 121. Thereby, it is possible to prevent the SMA fixing member 121 from being caught when it is fixed to the base member 101 by press fitting.

  Moreover, the shape by the another example of a crimping part is shown in FIG.2 (e). As shown in FIG. 2E, two grooves 121v may be formed on the end surface 121a of the SMA fixing member 121 in a cross shape. Thereby, the freedom degree of a rotation direction at the time of press-fitting the SMA fixing member 121 to the base member 101 increases. Further, as shown in FIG. 2 (f), a taper 121 t may be formed at the end 121 b of the SMA fixing member 121. Thereby, it is possible to prevent the SMA fixing member 121 from being caught when it is fixed to the base member 101 by press fitting. Any of the shapes shown in FIGS. 2A to 2F can be easily machined by well-known machining.

  The shape of the SMA fixing member 121 is formed in a cylindrical shape or a polygonal column shape as shown in FIGS. 3 (a) and 3 (b). When the groove 121v is formed around the side surface of the SMA fixing member 121 as shown in FIG. 2A, the SMA fixing member 121 is not required to be fixed to the base member 101. Accordingly, the shape of the SMA fixing member 121 is preferably cylindrical as shown in FIG. On the other hand, as shown in FIG. 2B, when the groove 121 v is formed in a “<” shape on a part of the side surface of the SMA fixing member 121, the base member 101 of the SMA fixing member 121 is formed. Therefore, the shape of the SMA fixing member 121 is preferably a polygonal column having a direction as shown in FIG. Note that the SMA fixing member 121 shown in FIG. 3B is formed in an octagonal prism shape as an example, but is not limited thereto, and may be an N prism (N is a positive integer), Moreover, D cut shape may be sufficient.

  As the material of the SMA fixing member 121, since the SMA 104 is held by the elastic force of the SMA fixing member 121 that has been caulked, if a material having a large Young's modulus is used, a large holding force can be obtained at the caulking portion. However, in the caulking operation, the greater the Young's modulus, the greater the amount of force required to deform the groove shape. Therefore, the deformation amount of the SMA 104 due to the caulking operation increases, and breakage is likely to occur in repeated driving operations. Therefore, it is preferable to use SUS steel or a copper-based metal material having a Young's modulus of 50 to 250 GPa in view of holding force and caulking pressure. In the case of a copper-based metal, it can be easily cut into a desired shape. In the case of using SUS steel, the material may be hardened due to internal stress generated in the process of processing the SMA fixing member 121. Therefore, heat treatment such as annealing or solution treatment may be performed to reduce the internal stress. desirable.

  Next, a method for fixing the SMA fixing member 121 to the base member 101 will be described.

  The base member 101 is formed to have a predetermined thickness because the base member 101 is required to have a strength against a caulking work load and a strength capable of stably holding the lens barrel 111 and the like. Further, as the material of the base member 101, a non-conductive material is used so that the two SMA fixing members 121 and 122 to which the energization members are connected via the terminal members 161 and 162 are not electrically short-circuited. In the case where a conductive material is used as the material of the base member 101, an insulation process is performed between the base member 101 and the two SMA fixing members 121 and 122.

  As a method for fixing the SMA fixing member 121 to the base member 100, insert molding for forming the SMA fixing member 121 integrally with the base member 101, or a hole for inserting the SMA fixing member 121 in the base member 101 is provided in advance. There is a method of fixing the fixing member 121 by press-fitting.

  Further, when the V-shaped groove 121v of the SMA fixing member 121 is not axially symmetric as shown in FIG. 2B, the groove 121v of the SMA fixing member 121 depends on the installation direction of the SMA 104. It is necessary to match the direction. In this case, the SMA fixing member 121 has a shape having a direction as shown in FIG. 3B, and the position of the groove 121v is set with respect to the direction. Specifically, in the case of insert molding, a shape that can set the direction with a mold is provided. In the case of press-fitting, the shape of the hole for press-fitting is a polygon or D-cut shape that can set the direction.

  Next, the caulking procedure will be described with reference to FIG. 1 and FIG.

  First, as shown in FIG. 1, the SMA 104 is locked to the locking portion 103 a of the drive lever 103 and is installed in a state where a predetermined tension is applied.

  Next, as shown in FIG. 2A, both ends of the installed SMA 104 are brought into contact with the groove 121v of the SMA fixing member 121 (122). Then, by pressing the caulking portion 121b of the SMA fixing member 121 (122) in such a manner in the direction of the arrow Y2, the SMA 104 is fixed in a manner such that the SMA 104 is sandwiched between the SMA fixing members 121 (122).

  Since the SMA fixing member 121 penetrates the base member 101 and is fixed, the end surface 121e opposite to the end surface 121a used for caulking the SMA fixing member 121 can be received when performing the caulking operation. As a result, the caulking force can directly apply a load to the SMA fixing member 121 without passing through other members, so that an unstable factor of caulking work is eliminated. As a result, the SMA can be securely fixed and stable production can be performed.

  Next, the cutting angle of the V-shaped groove 121v formed in the SMA fixing member 121 will be described with reference to FIG.

  In the caulking of the SMA fixing member 121, the groove 121v is plastically deformed to sandwich the SMA 104 and is deformed into a holding and fixing state. However, the shape of the groove 121v is symmetrical to the axial direction as shown in FIG. This deforms more uniformly in the length direction of the SMA 104 in the deformation process.

  Specifically, the shape of the groove 121v is formed in a V shape and the cut angle θ is set in a range of 15 ° to 40 °, so that the deformation of the SMA 104 in the length direction becomes uniform. If the deformation is not uniform, a large stress is applied to a portion where the deformation is large, and disconnection is easily caused by repeated driving operations. If the deformation is uniform, the holding force and the reliability can be improved. Further, by forming the groove 121v in such a shape, the influence of the caulking on the installation tension over the SMA 104 can be suppressed, so that the installation tension is stabilized and the assembly accuracy can be increased.

  Next, the terminal member 161 (162) will be described with reference to FIG. 4A is a schematic cross-sectional view showing the configuration of the terminal member 161 (162) and its periphery, and FIG. 2B is a schematic plan view.

  As shown in FIGS. 4A and 4B, the terminal member 161 (162) is formed in a shape that extends the periphery of the holding member 151 that holds the terminal member 161 (162). . One end side of the terminal member 161 (162) is provided with a press-fitting portion 161a (162a) in which the lower end side of the SMA fixing member 121 (122) is press-fitted to contact the SMA fixing member 121 (122), and the other end side is provided. Is provided with an energization connection portion 161b (162b) to which an energization member for supplying current to the SMA 104 is connected. Further, when the SMA fixing member 121 (122) is press-fitted into the press-fitting part 161a (162a), the press-fitting part 161a (162a) is displaced to the terminal member 161 (162) so that an error in the relative position between the two can be absorbed. For example, a movable part 161k (162k) such as an accordion is provided.

  The terminal member 161 (162) is insert-molded into a holding member 151 made of a non-conductive resin material that can be molded, such as plastic, with the press-fitting portion 161a (162a) and the energizing connection portion 161b (162b) exposed. Is retained.

  As shown in FIG. 5, the holding member 151 in which the terminal member 161 (162) is insert-molded as described above is connected to the base member 101 to which the SMA fixing member 121 (122) is fixed. The press-fit portion 161a (162a) and the SMA fixing member 121 (122) are overlapped and fixed so as to correspond to each other. At this time, the SMA fixing member 121 (122) is press-fitted into the press-fitting portion 161a (162a) of the terminal member 161 (162), whereby both are electrically connected.

  The holding member 151 in which the terminal member 161 (162) is insert-molded is fixed to the base member 101 after the SMA 104 is fixed to the SMA fixing member 121 (122) by caulking.

  Here, details of the press-fitting portion 161a (162a) will be described with reference to FIG. FIG. 6A is a schematic cross-sectional view showing an aspect in which the SMA fixing member 121 (122) is press-fitted into the press-fitting portion 161a (162a), and FIG. 6B is a schematic plan view. Since the press-fitting part 161a and the press-fitting part 161b have the same shape, only the press-fitting part 161a will be described in the following description.

  As shown in FIG. 6B, the press-fit portion 161a is formed in a ring shape having an opening 161o at the center. The SMA fixing member 121 is pressed into the periphery of the opening 161o from the periphery of the opening 161o toward the center of the opening 161o, so that the two beam portions 161x contacting the SMA fixing member 121 are opposed to each other. Is formed. As shown in FIG. 6A, the beam portion 161x is brought into contact with the SMA fixing member 121 while being bent by the press-fitting of the SMA fixing member 121.

  The beam portion 161x is in pressure contact with the SMA fixing member 121. However, if a load more than necessary is applied to the SMA fixing member 121, the installation tension of the SMA 104 is affected, so that electrical connection with the SMA fixing member 121 can be secured. It is necessary to abut on the SMA fixing member 121 with a pressurizing force sufficient to satisfy the above requirement. Such pressure (contact pressure) can be appropriately set according to the positional relationship between the position of the SMA fixing member 121 and the press-fit portion 161a, and the shape and material of the press-fit portion 161a. An appropriate contact state can be set by applying, for example, a conductive adhesive to the contact portion between the SMA fixing member 121 and the beam portion 161x.

  FIG. 7 shows a configuration example of the beam portion 161x. In the press-fit portion 161a shown in FIG. 7 (a), two beam portions 161x are provided, in the press-fit portion 161a shown in FIG. 7 (b), three beam portions 161x are provided, and the press-fit portion 161a shown in FIG. 7 (c). There are also four beam portions 161x. In either case, the SMA fixing member 121 is disposed so as to abut at equal intervals in the circumferential direction of the cross section.

  In this way, by providing at least two beam portions 161x and arranging them so as to contact each other at equal intervals in the circumferential direction of the cross section of the SMA fixing member 121, the plurality of beam portions 161x are arranged in the circumferential direction of the cross section of the SMA fixing member 121. The contact pressure necessary for conduction can be obtained without canceling the applied pressure and affecting the installation tension of the SMA 104. The arrangement of the beam portions 161x is not limited to being equidistant in the circumferential direction of the cross section of the SMA fixing member 121, and as shown in FIG. 7D, the SMA fixing member 121 including a plurality of beam portions 161x. It suffices if the vector sum of the applied pressures is substantially zero.

  Next, a driving method of the lens driving device 1 will be described. The control of the SMA 104 uses the fact that the resistance value of the SMA 104 has a linear relationship with the deformation amount. Specifically, the amount of deformation required to move the lens barrel 111 by a predetermined amount can be calculated from the total length of the SMA 104, and therefore corresponds to the amount of deformation of the SMA 104 required to drive the lens barrel 111 to the target position. Calculate the resistance value. Next, the lens barrel 111 is driven by controlling the driving voltage of the SMA 104 so that the resistance value of the SMA 104 becomes the target resistance value.

  FIG. 8 shows an example of the control system 20 of the lens driving device 1. As shown in FIG. 8, the control system 20 includes a comparison unit 201, a control unit 202, a drive unit 203, a resistance value detection unit 204, and the like. The drive voltage of the SMA 104 is controlled so that the resistance value of the SMA 104 is made closer.

  First, the resistance value detection unit 204 detects the resistance value of the SMA 104 provided in the lens driving device 1. The comparison unit 201 compares the resistance value of the SMA 104 detected by the resistance value detection unit 204 with the target resistance value from the camera body, and calculates a difference. The control unit 202 calculates the drive voltage value of the SMA 104 according to the difference calculated by the comparison unit 201. The driving unit 203 generates a driving voltage based on the driving voltage value of the SMA 104 calculated by the control unit 202 and applies the driving voltage to the SMA 104. The SMA 104 is deformed by the driving voltage applied from the driving unit 203 and the lens barrel 111 is driven. By repeating such an operation until the difference calculated by the comparison unit 201 becomes 0, the lens barrel 111 can be driven to the target position.

  As described above, in the lens driving device 1 according to the embodiment of the present invention, the SMA 104 is sandwiched by crimping one end side of the rod-shaped terminals (SMA fixing members 121 and 122) fixed through the base member 101, and the other end. The terminal member 161 (162) is brought into contact with the rod-shaped terminal by press-fitting the side into a terminal member 161 (162) to which an energizing member for supplying current to the SMA 104 is connected. In this case, a predetermined thickness is required for the base member 101 to penetrate and hold the rod-shaped terminal with sufficient strength. Therefore, the crimping portion (end portion) on one end side where the SMA 104 of the rod-shaped terminal is fixed by pressure bonding is used. 121b) and the distance between the other end side where the press-fitting portion 161a (162a) of the terminal member 161 (162) abuts is secured at least by the thickness of the base member 101. Furthermore, a current-carrying member is connected to the rod-shaped terminal via a terminal member 161 (162).

  As a result, when the current-carrying member is connected to the terminal member 161 (162) by, for example, soldering, it is possible to ensure a sufficient distance that the heat conduction during the soldering operation does not affect the performance of the SMA 104. In addition, there is heat dissipation to the base member 101 that fixes the rod-shaped terminal and the holding member 151 that holds the terminal member 161 (162). As a result, heat conduction to the SMA 104 can be suppressed, and deterioration of the performance of the SMA 104 can be prevented.

  Further, the contact pressure when the terminal member 161 (162) is in contact with the rod-shaped terminal may be sufficient to ensure electrical continuity with the rod-shaped terminal. Such contact pressure can be determined by the positional relationship between the rod-shaped terminal and the terminal member 161 (162), and the shape and material of the press-fitting portion 161a (162a) of the terminal member. Therefore, a large load due to the contact of the terminal member 161 (162) is not hung on the rod-shaped terminal. For this reason, when connecting an electricity supply member to the terminal member 161 (162), the load concerning a rod-shaped terminal in the case of a connection operation | work can be suppressed. As a result, the influence on the installation tension of the SMA 104 can be suppressed.

  Further, the position of the energizing connection portion 161b (162b) to which the energizing member of the terminal member 161 (162) is connected is not limited to the position of the rod-shaped terminal where the SMA 104 is held, and the position of the energizing member such as a lead wire is not limited. It can be provided at a desired position in consideration of scooping. Thereby, in the limited space of the apparatus in which the drive device 1 is mounted, it is possible to easily handle the current-carrying member such as the lead wire and to reduce the size of the apparatus.

  As a result, the SMA 104 can be stably fixed and the current-carrying member can be connected without hindering downsizing of the apparatus and without affecting the performance of the SMA 104.

DESCRIPTION OF SYMBOLS 1 Lens drive device 101 Base member 102 Hinge 103 Drive lever 104 SMA
105 Coil spring 106 Leaf spring 107 Cover 111 Lens barrel 112 Lens 113a, 113b Contact member 121, 122 SMA fixing member (bar-shaped terminal)
151 Holding member 161, 162 Terminal member 5 Caulking jig 20 Control system 201 Comparison unit 202 Control unit 203 Drive unit 204 Resistance value detection unit

Claims (11)

In a drive device provided with a string-like shape memory alloy as a drive source,
A base member serving as a base of the driving device;
A bar-like terminal made of a metal that penetrates the base member and is fixed to the base member, and which is crimped at one end to sandwich the shape memory alloy;
A terminal member electrically connected to the other end side of the rod-shaped terminal,
The terminal member is
A press-fitting portion in which the other end side of the rod-like terminal is press-fitted into one end side of the terminal member and comes into contact with the rod-like terminal;
A drive device comprising: a current-carrying connection portion to which a current-carrying member for supplying a current to the shape memory alloy is connected to the other end side of the terminal member, and being held by a predetermined member . Holding the terminal member and having a holding member fixed to the base member;
2. The driving device according to claim 1, wherein the terminal member is insert-molded and held in the holding member in a form in which the press-fitting portion and the energization connection portion of the terminal member are exposed. The press-fitting portion of the terminal member has an opening into which the other end side of the rod-shaped terminal is press-fitted,
At the periphery of the opening, at least two beam portions that contact the rod-shaped terminal are formed by press-fitting the other end of the rod-shaped terminal from the periphery of the opening toward the center of the opening. The drive device according to claim 1, wherein the drive device is provided.   4. The driving device according to claim 3, wherein the at least two beam portions of the press-fitting portion are disposed so as to abut at equal intervals in the circumferential direction of the cross-section of the rod-shaped terminal.   The at least two beam portions of the press-fit portion are arranged so that a vector sum of pressure applied to the rod-shaped terminal by the at least two beam portions is substantially zero. Drive device.   6. The press-fitting portion of the terminal member is formed so as to be displaceable with respect to a portion of the rod-shaped terminal that is insert-molded in the holding member. Drive device.   The drive device according to any one of claims 1 to 6, wherein the rod-shaped terminal is a metal having a Young's modulus of 50 GPa or more and 250 GPa or less.   The drive device according to claim 7, wherein the rod-shaped terminal is made of a copper-based metal.   The drive device according to claim 7, wherein the rod-shaped terminal is made of SUS steel.   10. The driving device according to claim 1, wherein a caulking portion for sandwiching the shape memory alloy is formed on a side surface or an end surface of one end side of the rod-shaped terminal.   11. The driving device according to claim 1, wherein a cross section in a radial direction of the rod-shaped terminal is formed in a circular shape or a polygonal shape.

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