JP2005083291A - Driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving device arrangeable in a narrow space and capable of efficiently generating sufficient output. <P>SOLUTION: This driving device has a shape memory alloy wire 2, a spring 4 for energizing the shape memory alloy wire 2, a rotating member 8 obtaining rotational output from the displacement of the shape memory alloy wire 2, and a base 6 for supporting them. The shape memory alloy wire 2 is wound around the rotating member 8, and the shape memory alloy wire 2 of sufficient length can be arranged in the narrow space. As a result, sufficient rotational output can be generated in the narrow space. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a driving apparatus that generates a driving force using a shape memory alloy.

  Conventionally, as a driving device disposed in a narrow space inside a small device or the like, a device that rotates an operation dial using a shape alloy wire (see, for example, Patent Document 1), and a lens drive using an ultrasonic motor There are known those that rotate a cylindrical cam or the like (for example, see Patent Document 2), or those that rotate a lens driving actuator with a shape memory alloy wire (for example, see Patent Document 3). Also known is a drive device in which a rotating shaft is rotated using a spiral shape memory alloy (see, for example, Patent Documents 4, 5 and 6).

Japanese Patent Laid-Open No. 11-344754 (page 5, FIG. 4) JP 09-043476 A (page 2-3, FIG. 2) JP 2002-244015 A (page 4-5, FIG. 1) JP 09-268969 (page 2-3, FIG. 1) Japanese Patent Laid-Open No. 10-288679 (page 2-3, FIG. 1) JP 07-103129 A (page 3-4, FIG. 1)

  However, the amount of displacement of the shape memory alloy wire (i.e., the total elongation) is generally about 3% to 5% of the total length of the wire. Therefore, if the shape memory alloy wire is arranged linearly as in the drive devices described in Patent Document 1 and Patent Document 3, the total length of the shape memory alloy wire cannot be made very long due to the installation space. There is a problem that a sufficient amount of displacement cannot be obtained. Further, when an ultrasonic motor is used as in the drive device described in Patent Document 2, there is a problem that a larger installation space is required than a drive device using a shape memory alloy.

  Further, when a spiral shape memory alloy is used as in Patent Documents 4 to 6, there is a problem that it is difficult to reduce the size of the drive device due to the spiral shape. Further, since the rotational output is obtained by changing the curvature of the spiral shape memory alloy, a large displacement cannot be obtained for the entire length (that is, the space efficiency is low). As a result, there is a problem that power consumption is large or high responsiveness cannot be obtained.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize a drive device that can be disposed in a narrow space and can efficiently generate a sufficient output. .

  The drive device according to the present invention includes an elongated shape memory alloy member, a rotating member that obtains a rotational output from the displacement of the shape memory alloy member, and a biasing force that biases the shape memory alloy member in a direction that suppresses the displacement. And a base that supports the shape memory alloy member, the rotating member, and the biasing member, and the shape memory alloy member is wound around the rotating member. .

  According to the present invention, since the shape memory alloy member is wound directly or indirectly around the rotating member, the shape memory alloy member having a sufficient length can be disposed in a narrow space, and as a result, sufficient A displacement amount can be obtained. Furthermore, since a rotational output can be obtained by using displacement due to expansion and contraction of the shape memory alloy member, a large output can be obtained even in the same space as compared with the case where a spiral shape memory alloy is used. That is, it is possible to realize a drive device that can be arranged in a narrow space and can generate a sufficient output efficiently.

Embodiment 1 FIG.
FIG. 1 is a perspective view for explaining the configuration of a drive apparatus 1 according to Embodiment 1 of the present invention. The drive device 1 includes a base 6 having a substantially rectangular horizontal upper surface, and a substantially columnar rotating member 8 provided on the base 6. The rotating member 8 is configured to be rotatable around a central axis C in the vertical direction. In the description of the driving device, words such as up, down, front, back, left, right, vertical, horizontal, clockwise, counterclockwise are used for convenience of description. The orientation is not limited.

  The driving device 1 further includes a wire made of a shape memory alloy, that is, a shape memory alloy wire (shape memory alloy member) 2. On the base 6, a fixing member 6 a for fixing one end of the shape memory alloy wire 2 is erected on the right side of the rotating member 8 in the drawing. A fixing portion 3 for fixing the other end of the shape memory alloy wire 2 is provided on the outer peripheral surface of the rotating member 8 on the front side in the drawing. One end of the shape memory alloy wire 2 is fixed to the fixing member 6 a and is wound around the outer peripheral surface of the rotating member 8, and the other end is fixed to the fixing portion 3. Here, the shape memory alloy wire 2 is wound at an angle of about 270 degrees in the top view (viewed from the direction indicated by the arrow A) with respect to the central axis C of the rotating member 8. Can be appropriately changed according to a desired rotation output, arrangement space, and the like.

  As an example of a method of fixing the shape memory alloy wire 2, the fixing member 6a and the fixing portion 3 are formed in a pin shape, and both ends of the shape memory alloy wire 2 have connection terminals (for example, round holes engaged with the pins). A metal plate) is attached, and these connection terminals are engaged with the fixing member 6a and the fixing portion 3, respectively. However, the method for fixing the shape memory alloy wire 2 is not limited to this method.

  One end of a spring (biasing member) 4 is fixed to the fixing portion 3 of the rotating member 8. The spring 4 is a tension coil spring, for example, and is provided so that its axial direction is horizontal. The other end of the spring 4 is fixed to a fixing member 6b erected on the base 6 adjacent to the fixing member 6a. The spring 4 gives the shape memory alloy wire 2 an urging force in a direction to suppress the displacement.

  As an example of the fixing method of the spring 4, the fixing member 6b and the fixing portion 3 are formed in a pin shape, and the loop-shaped portions formed at both ends of the spring 4 are engaged with the fixing member 6b and the fixing portion 3, respectively. However, the fixing method of the spring 4 is not limited to this method. The spring 4 is not limited to a tension coil spring, and an elastic member such as a compression coil spring, a torsion coil spring, a leaf spring, or rubber can be used.

  An energization circuit 7 is connected to the fixing member 6 a and the fixing portion 3. Both the fixing member 6 a and the fixing portion 3 are made of a conductive member, and the energization circuit 7 can pass a current through the shape memory alloy wire 2. The shape memory alloy wire 2 is configured to be heated and contracted by Joule heat when energized by the energization circuit 7, and to expand and return to its original length when energization is stopped.

  Next, the operation of the drive device 1 will be described. FIG. 2 is a diagram for explaining the operation of the driving device 1, and is a plan view seen from the direction of the arrow A shown in FIG. In a state where no current flows through the shape memory alloy wire 2, the shape memory alloy wire 2 is in an extended state as shown in FIG. 2A, and the fixing member 6 a and the fixing portion 3 are applied by the urging force of the spring 4. It is stretched without bending between. When the current-carrying circuit 7 (FIG. 1) passes a current through the shape memory alloy wire 2 and the shape memory alloy wire 2 contracts, the fixing portion 3 is moved to the left in the figure by the shape memory alloy wire 2 as shown in FIG. Biased in the direction. Thereby, the rotating member 8 on which the fixing portion 3 is formed rotates clockwise against the elastic force of the spring 4. On the other hand, when the energization circuit 7 (FIG. 1) stops energization, the shape memory alloy wire 2 is stretched and returns to its original length, so that the fixing portion 3 is urged rightward in the figure by the urging force of the spring 4. Thereby, the rotating member 8 rotates counterclockwise and returns to the initial state shown in FIG.

  As described above, according to the driving device 1 according to the first embodiment, the long shape memory alloy wire 2 is arranged in a narrow space by winding the shape memory alloy wire 2 around the rotating member 8. Therefore, sufficient rotation output can be obtained.

  In addition, since the expansion and contraction of the shape memory alloy wire 2 having a thin wire diameter is used, the volume of the shape memory alloy wire 2 is very large compared to a spiral shape memory alloy (a wire having a large wire diameter is used). Get smaller. Therefore, when the shape memory alloy wire 2 is heated by flowing a current, the shape memory alloy wire 2 can be deformed with a smaller current, and the power consumption can be reduced.

  In the above description, the shape memory alloy wire 2 is displaced by energization, but may be displaced by heating from the outside. Also in this case, it can be arranged in a narrower space than a drive device using a spiral shape memory alloy, and since the volume of the shape memory alloy wire 2 is very small, it can be heated and deformed in a short time. . Therefore, high thermal responsiveness can be obtained. In the above description, the rotary member 8 has a cylindrical shape. However, the rotary member 8 is not particularly limited to a cylindrical shape, and may be a polygonal column shape such as a pentagonal column or a hexagonal column.

  FIG. 3 is a perspective view showing a driving apparatus 1A according to a first modification of the first embodiment. The driving device 1A according to this modification is provided with a guide groove (groove portion) for preventing the vertical displacement of the shape memory alloy wire 2 in the rotating member 8 of the driving device 1 (FIG. 1) described in the first embodiment. ) 81 is formed. The configuration other than the guide groove 81 is the same as that of the driving device 1 described in the first embodiment. When the shape memory alloy wire 2 is wound around the rotating member 8, the shape memory alloy wire 2 may be wound along the guide groove 81, so that the winding operation is facilitated. Furthermore, since the displacement of the shape memory alloy wire 2 can be prevented, when the shape memory alloy wire 2 is wound a plurality of times, a short circuit due to contact between the shape memory alloy wires 2 can be prevented, and the shape memory alloy can be prevented. Short-circuiting due to contact between the wire 2 and peripheral members can be prevented.

  FIG. 4 is a perspective view showing a driving apparatus 1B according to a second modification of the first embodiment. In the driving device 1B according to this modification, a step 82 is formed in the rotating member 8 instead of the guide groove 81 (FIG. 3) described in the first modification. That is, the lower portion of the rotating member 8 is configured to have a smaller diameter than the upper portion, and the shape memory alloy wire 2 is wound along the step portion 82 formed therebetween. When the shape memory alloy wire 2 is wound around the rotary member 8, the shape memory alloy wire 2 may be wound along the stepped portion 82, so that the winding operation is facilitated.

Embodiment 2. FIG.
FIG. 5 is a perspective view showing a configuration of drive apparatus 10 according to Embodiment 2 of the present invention. The driving apparatus 10 according to the second embodiment is different from the driving apparatus 1 according to the first embodiment in that a plurality of discrete contact portions 15 are provided in a portion where the shape memory alloy wire 2 of the rotating member 18 is wound. ing. In FIG. 5, the same reference numerals are given to components common to the drive device 1 (FIG. 1) according to the first embodiment.

  The contact portion 15 is constituted by a tip portion of a protrusion protruding outward in the radial direction of the rotating member 18, and this tip portion contacts the shape memory alloy wire 2 with a curved surface having a certain width and curvature as will be described later. doing. Further, the protrusions constituting the contact portion 15 extend in a direction substantially orthogonal to the circumferential direction of the rotating member 18 (winding direction of the shape memory alloy wire 2), and are spaced at a certain interval in the circumferential direction of the rotating member 18. Many are formed. A fixing portion 13 that fixes one end of the shape memory alloy wire 2 protrudes from the outer peripheral surface of the rotating member 18. The fixing portion 13 is disposed between the two contact portions 15.

  As compared with the case where the shape memory alloy wire 2 is freely displaced without contact with other components, the amount of displacement tends to decrease as the contact with other components increases. However, in the driving apparatus 10 according to the second embodiment, the discretely provided contact portions (tip portions of the protrusions) 15 are in contact with the shape memory alloy wire 2. Small contact with parts. Therefore, a decrease in the amount of displacement can be minimized as compared with the case where the shape memory alloy wire 2 is freely displaced without contact with other parts.

  FIG. 6 is a diagram illustrating a specific configuration example of the rotating member 18. FIG. 6A is a perspective view schematically showing the outer shape of the rotating member 18. FIGS. 6B to 6D are plan views showing three specific examples of the rotating member 18, all of which have an arrangement pitch (P) of 1.56 mm in the circumferential direction of the rotating member 18 having an outer shape of 10 mm. Twenty contact portions 15 are provided. In addition, each contact portion 15 is configured to contact the shape memory alloy wire 2 on a cylindrical surface (that is, a surface forming an arc when viewed from above) centering on the central axis of the rotating member 18.

  In the three specific examples shown in FIGS. 6B to 6D, the length H in the circumferential direction of the rotating member 18 of each contact portion 15 is varied in three ways. In the rotating member 18 shown in FIG. 6B, the length H of each contact portion 15 is 1.05 mm, and the width of the recess between adjacent contact portions 15 is 0.52 mm. In the rotating member 18 shown in FIG. 6C, the length H of each contact portion 15 is 0.78 mm, and the width of the concave portion between adjacent contact portions 15 is 0.78 mm. In the rotating member 18 shown in FIG. 6D, the length H of each contact portion 15 is 0.52 mm, and the width of the recess between adjacent contact portions 15 is 1.05 mm.

  FIG. 7 is a diagram illustrating an experimental method relating to a specific shape of the rotating member 18 illustrated in FIGS. Here, metal pins 161 and 162 erected on the base 6 are used as the fixing members 6a and 6b (FIG. 5), and metal pins erected on the outer peripheral surface of the rotating member 18 as the fixing portion 3 (FIG. 5). 131 is used. Further, connection terminals (metal plates having round holes that engage the pins: caulking terminals) 21 and 22 are attached to both ends of the shape memory alloy wire 2, and the connection terminals 21 are attached to the metal pins 161 on the base 6. The connection terminal 22 is fixed to the metal pin 131 of the rotating member 18. In addition, the loop-shaped portions formed at both ends of the spring 4 are hooked and fixed to the metal pin 131 of the rotating member 18 and the metal pin 162 on the base 6 respectively. The energization circuit 7 is connected to the metal pins 161 and 162, and allows a current to flow through the shape memory alloy wire 2 via the spring 4, the metal pin 131 and the connection terminals 21 and 22. Here, the spring 4 and each metal pin 131,161,162 shall have electroconductivity.

  In the experiment shown in FIG. 7, the material of the rotating member 18 is POM (polyoxymethylene). The shape memory alloy wire 2 has a wire diameter of about 60 microns and a length of 50 mm. The shape memory alloy wire 2 is wound about 360 degrees around the outer periphery of the rotating member 18. The direct current passed through the shape memory alloy wire 2 by the energizing circuit 7 is about 140 mA. The biasing force of the spring (tensile coil spring) 4 is 0.39 N (40 gf) in the initial state (the state before the current is passed through the shape memory alloy wire 2).

  With respect to the three types of rotating members 18 shown in FIGS. 6B to 6D, a 140 mA direct current was passed through the shape memory alloy wire 2 and the rotation angle of the rotating member 18 was measured. The results are shown in Table 1 and FIG. In Table 1 and FIG. 8, the contact ratio is the ratio (100 × H / P) of the length H of the contact portion 15 to the arrangement pitch P (1.56 mm) of the contact portion 15. Further, in Table 1 and FIG. 8, the shape memory alloy wire 2 is wound about 360 degrees around the outer periphery of a cylindrical rotating member 18 having a diameter of 10 mm (contact ratio 100%), and a 140 mA direct current is applied to the shape memory alloy wire 2. The results of measuring the rotation angle of the rotating member 18 are also shown.

  From FIG. 8 and Table 1, it can be seen that the displacement angle of the rotating member 18 increases substantially linearly as the contact ratio decreases. In particular, when the contact ratio is 33%, it can be seen that a rotation angle about three times that obtained when the shape memory alloy wire 2 is wound around the outer periphery of the cylindrical rotating member (contact ratio 100%) can be obtained. From the above, it can be seen that the output of the rotation angle can be increased by providing the contact portion 15, and the output of the rotation angle can be increased as the contact ratio is decreased.

  As described above, according to the driving device 10 according to the second embodiment, in addition to the effects described in the first embodiment, the contact between the shape memory alloy wire 2 and other components is reduced. The displacement amount of the shape memory alloy wire 2 can be increased and a large rotational output can be obtained. That is, it is possible to realize a driving device that is smaller and has a large output.

  In addition, since the contact portion 15 contacts the shape memory alloy wire 2 with a curved surface having an arc shape when viewed from above, stress concentration due to sudden bending on the shape memory alloy wire 2 can be avoided. Moreover, it becomes difficult to bend a bend and the reliability of the drive device is improved.

  As described in the modification of the first embodiment (FIGS. 3 and 4), the guide groove 81 (FIG. 3) or the step portion 82 is provided in the portion of the rotating member 18 where the shape memory alloy wire 2 is wound. It is also possible to provide (FIG. 4). This facilitates the winding of the shape memory alloy wire 2 around the rotating member 18, and in particular, when the guide groove 81 is provided, the occurrence of a short circuit due to the displacement of the shape memory alloy wire 2 is reliably prevented. can do.

Embodiment 3 FIG.
FIG. 9 is a perspective view showing the configuration of the drive device 20 according to Embodiment 3 of the present invention. In the driving device 20 according to the third embodiment, the rotating member 28 has a fixing portion (first fixing portion) 23a for fixing the shape memory alloy wire 2 and a fixing portion (second fixing portion) for fixing the spring 4. 23b is different from the driving device 1 according to the first embodiment in that it has 23b separately. In FIG. 9, the same reference numerals are given to components common to the drive device 1 (FIG. 1) according to the first embodiment.

  The rotating member 28 is a substantially columnar member provided on the base 6 so as to be rotatable around a central axis in the vertical direction. The rotating member 28 has two fixing portions 23a and 23b on the front side of the outer peripheral surface in the figure. One end of the shape memory alloy wire 2 is fixed to a fixing member 6 a erected on the base 6, and the other end of the shape memory alloy wire 2 is fixed to a fixing portion 23 a of the rotating member 28. One end of the spring 4 is fixed to a fixing portion 23 b of the rotating member 28, and the other end of the spring 4 is fixed to a fixing portion 6 b erected on the base 6. Other configurations are the same as those in the first embodiment.

  The fixing portion 23a is, for example, a pin-shaped member, and is configured such that a connection terminal (for example, a metal plate having a round hole that engages with the pin) attached to the end portion of the shape memory alloy wire 2 is engaged. Yes. Moreover, the fixing | fixed part 23b is also a pin-shaped member, for example, and it is comprised so that the loop-shaped part formed in the edge part of the spring 4 may engage. However, the fixing portions 23a and 23b are not limited to such a configuration. Note that the guide groove 81 (FIG. 3) or the stepped portion 82 (FIG. 4) described in the modification of the first embodiment may be provided in a portion of the rotating member 28 where the shape memory alloy wire 2 is wound.

  According to the driving device 20 according to the third embodiment, in addition to the effects described in the first embodiment, the arrangement of the spring 4 can be determined independently of the arrangement of the shape memory alloy wire 2, The arrangement of the springs 4 can be freely determined according to the shape of the installation space of the drive device 1 and the like. As a result, a smaller drive device can be realized.

Embodiment 4 FIG.
FIG. 10A is an exploded perspective view showing the configuration of the drive device 30 according to Embodiment 4 of the present invention, and FIG. 10B is an enlarged perspective view showing a part of the drive device 30. is there. FIG. 11A is a cross-sectional view showing the configuration of the drive device 30. In the driving device 30 according to the fourth embodiment, the shape memory alloy wire 2 is wound around a driving ring 39 provided around the rotating member 38, and the rotating member 38 is rotated via the driving ring 39. However, the driving device 1 is different from the driving device 1 according to the first embodiment. In FIG.10 and FIG.11, the same code | symbol is attached | subjected to the component which is common in the drive device 1 (FIG. 1) which concerns on Embodiment 1. FIG.

  As shown in FIG. 10 (a), the rotating member 38 is a substantially columnar member provided rotatably around a central axis in the vertical direction. The drive ring (drive member) 39 is an annular member provided so as to surround the periphery of the rotation member 38. The drive ring 39 is rotatably supported inside an annular holding portion 361 provided on the base 6.

  As shown in FIG. 11A, a large number of claw portions 382 and concave portions 381 are formed on the outer peripheral surface of the rotating member 38 on the base 6 side (near the lower end portion). Each claw 382 has an inclined surface 382a extending in the tangential direction of the rotation circumference of the rotating member 38 and an abutting surface 382b substantially orthogonal to the tangential direction, and the abutting surface 382b is an inclined surface. It is located in the clockwise direction with respect to 382a. A recess 381 is formed between the adjacent claw portions 382.

  A claw portion (convex portion) 391 that engages with the concave portion 381 of the rotating member 38 is provided inside the drive ring 39. The claw portion 391 is supported by a groove portion 393 formed in the drive ring 39 so as to be movable in the radial direction of the drive ring 39, and is urged by a spring 392 toward the center of the drive ring 39. The claw portion 391 has an inclined surface 391 a that can contact the inclined surface 382 a of the rotating member 38 and an abutting surface 391 b that can contact the abutting surface 382 b of the rotating member 38.

  One end of the shape memory alloy wire 2 is fixed to a fixing member 6 a erected on the base 6. The shape memory alloy wire 2 is wound around the outer peripheral surface of the drive ring 39, and the other end is fixed to a fixing portion 33 formed to protrude from the outer peripheral surface of the drive ring 39. One end of the spring 4 is fixed to the fixing portion 33, and the other end of the spring 4 is fixed to a fixing member 6 b erected on the base 6. A specific example of the method for fixing the shape memory alloy wire 2 and the spring 4 is as described in the first embodiment.

  FIG. 11B and FIG. 11C are cross-sectional views for explaining the operation of the driving device 30. When an electric current is passed through the shape memory alloy wire 2 by the energization circuit 7, the shape memory alloy wire 2 contracts to urge the fixing portion 33 of the drive ring 39 as shown in FIG. Rotate counterclockwise (arrow CCW). When the drive ring 39 rotates counterclockwise, the claw portion 391 attached to the drive ring 39 engages with the concave portion 381 of the rotating member 38 by the biasing force of the spring 392. As a result, the rotating member 38 rotates counterclockwise together with the drive ring 39.

  On the other hand, when the energization circuit 7 stops energizing the shape memory alloy wire 2, the shape memory alloy wire 2 extends and returns to its original length, and therefore, as shown in FIG. The drive ring 39 rotates clockwise (arrow CW) and returns to the state shown in FIG. When the drive ring 39 rotates clockwise, the inclined surface 391 a of the claw portion 391 contacts the claw portion 382 of the rotating member 38 while sliding, and the claw portion 391 is pushed into the groove portion 393. Thereby, since the engagement between the claw portion 391 and the concave portion 381 of the rotating member 38 is released, the rotating member 38 does not rotate even when the drive ring 39 rotates. That is, only the drive ring 39 returns to the original position, and the rotating member 38 remains at the rotating position in FIG. Therefore, by repeating energization to the shape memory alloy wire 2 by the energization circuit 7, the rotating member 38 can be intermittently rotated to obtain a desired rotation angle. Further, since the rotating member 38 does not return to the original position even when the energization of the energizing circuit 7 is stopped, the rotating member 38 can be stopped at a desired rotating position.

  Note that the claw portion 391 and the spring 392 shown in FIG. 11 are each composed of a member different from the drive ring 39, but can be formed integrally with the drive ring 39. That is, as shown in FIG. 12, a notch 394 is formed along the inner periphery of the drive ring 39 to form a cantilever-shaped portion 395, and a claw protruding toward the rotating member 38 at the tip thereof. A portion 396 is formed. The cantilever-like portion 395 is bent to act in the same manner as a spring, and the claw portion 396 can be engaged with the recess 381 of the rotating member 38. Further, the guide groove 81 (FIG. 3) or the stepped portion 82 (FIG. 4) described in the modification of the first embodiment may be provided in a portion where the shape memory alloy wire 2 of the drive ring 39 is wound.

  As described above, according to the driving device 30 according to the fourth embodiment, in addition to the effects described in the first embodiment, the rotating member 38 is rotated intermittently (for example, one by one of the claw portions 391). Since the rotation member 38 can be stopped at a desired rotation position by stopping energization, the power consumption of the drive device 30 can be reduced. Moreover, deterioration of the shape memory alloy wire 2 can be suppressed by shortening the energization time.

Embodiment 5 FIG.
13 and 14 (a) are a cross-sectional view and an exploded perspective view showing a configuration of a drive device 40 according to Embodiment 5 of the present invention. The driving device 40 according to the fifth embodiment is configured to drive the lens frame of the imaging device (for example, a camera) using the rotating member described in the fourth embodiment. In FIG. 13 and FIG. 14, the same code | symbol is attached | subjected to the component which is common with the drive device 1 (FIG. 10 and FIG. 11) which concerns on Embodiment 4. FIG.

  In an imaging device such as a camera, the lens 482 is disposed so as to form a subject image on the imaging surface (imaging element 462). However, when close-up photography is performed close to the subject, the image point is behind the lens 482 ( In order to obtain a clear image of the subject, it is necessary to increase the distance between the lens 482 and the imaging surface. In the fifth embodiment, the lens 482 is driven in the optical axis direction (X direction) using the driving device 40, so that the position of the lens 482 is the standard position during normal shooting and the close-up position during close-up shooting. Switch between.

  The lens 482 has an optical axis X in the vertical direction in the drawing. The lens frame 481 that holds the lens 482 is a substantially cylindrical member that is configured so that the center axis thereof is substantially parallel to the optical axis X. As a cam mechanism for moving the lens frame 481 in the direction of the optical axis X, a cam ring 486 (first member) and a cam follower ring 485 (second member) are provided. The cam follower ring 485 is fixed near the lower end of the outer peripheral surface of the lens frame 481. A screw portion 481b is formed on the outer peripheral surface of the lens frame 481, and a screw portion 485b that is screwed into the screw portion 481b of the lens frame 481 is formed on the inner peripheral surface of the cam follower ring 485. On the lower surface of the cam follower ring 485, six cam followers 485a (only three are shown in FIG. 13) are formed.

  The cam ring 486 is provided on the base 46 and includes six cams 486a (only three are shown in FIG. 13) protruding upward. The cam 486a includes a bottom portion 486b and a top portion 486d, which are horizontal surfaces having different heights, and an inclined portion 486c formed therebetween. A drive ring 49 for rotating the cam ring 486 is provided outside the cam ring 486. The drive ring 49 is rotatably held inside holding portions 463 and 464 (FIG. 14A) formed in a substantially annular shape on the base 46, and is formed by the shape memory alloy wire 2 as will be described later. Driven by rotation.

  A cap 483 is provided so as to cover the lens frame 481 and the cam follower ring 485. The cap 483 is a substantially cylindrical member whose central axis is substantially parallel to the optical axis X. A large diameter portion 483 b is formed at the lower end of the cap 483. The large-diameter portion 483b of the cap 483 is fixed to the holding portions 463 and 464 (FIG. 14A) on the base 46 by welding using an adhesive, a solvent, ultrasonic waves or the like, or depending on the shape, by a snap fit or the like. Has been. A spring (for example, an elastic member such as a coil spring) 484 that urges the cam follower ring 485 toward the cam ring 486 is provided around the lens frame 481 inside the cap 483.

  An opening 483c into which the lens frame 481 can be inserted is formed at the upper end of the cap 483. A groove 483a extending in the direction of the optical axis X of the cap 483 is formed on the inner peripheral surface of the opening 483c. Is formed. The groove 483a engages with a guide portion 481a formed on the outer peripheral surface of the upper end portion of the lens frame 481, so that the lens frame 481 (and the cam follower ring 485 fixed to the lens frame 481) is connected to the optical axis X. You will be guided straight in the direction of.

  FIG. 14B is a plan view of the cam ring 486 viewed from the direction of arrow C shown in FIG. A large number of claw portions 494 protrude from the outer peripheral surface of the cam ring 486, and a recess 493 is formed between adjacent claw portions 494. The nail | claw part 494 and the recessed part 493 are each comprised similarly to the nail | claw part 382 and the recessed part 381 (FIG. 11) demonstrated in Embodiment 4. FIG. On the other hand, as shown in FIG. 13, a claw portion (convex portion) 491 that can be engaged with the concave portion 493 of the cam ring 486 is provided on the inner peripheral surface of the drive ring 49. The claw portion 491 is configured similarly to the claw portion 391 (FIG. 11) described in the fourth embodiment, and is biased toward the inside of the drive ring 49 by a spring 492 (FIG. 13). That is, when the drive ring 49 rotates counterclockwise (indicated by arrow A), the cam ring 486 is driven to rotate counterclockwise by the engagement of the claw portion 491 and the recess 493, but the drive ring 49 rotates clockwise. When rotating around (indicated by arrow B), the claw portion 491 and the concave portion 493 are not engaged, and the cam ring 486 does not rotate.

  The shape memory alloy wire 2 is wound around the outer periphery of the drive ring 49. One end of the shape memory alloy wire 2 is fixed to a fixing member 6 a erected on the base 46, and the other end of the shape memory alloy wire 2 is fixed to the outer peripheral surface of the drive ring 49. 43 is fixed. One end of the spring 4 is fixed to the fixing portion 43, and the other end of the spring 4 is fixed to a fixing member 6 b erected on the base 46. A specific example of the method of fixing the shape memory alloy wire 2 and the spring 4 is as described in the first embodiment.

  The base 46 has a hole (opening) 461 through which the light beam collected by the lens 482 passes. An imaging element 462 is disposed below the hole 461 of the base 46 and at an image formation position by the lens 482.

  As shown in FIG. 13, when the lens frame 481 is rotated with respect to the cam follower ring 485 before the cam follower ring 485 and the lens frame 481 are fixed, the lens frame 481 is rotated by the screws 485b and 481b. Since the distance between the lens 482 and the image sensor 462 changes in the X direction, the focus of the lens 482 can be adjusted. After the focus adjustment is completed, the lens frame 481 and the cam follower ring 485 are fixed to each other by welding using an adhesive, a solvent, ultrasonic waves, or the like.

  When an electric current is passed through the shape memory alloy wire 2 by the energization circuit 7, the shape memory alloy wire 2 contracts and urges the fixing portion 43 to rotate the drive ring 49 counterclockwise (in the direction of arrow A in FIG. 14A). Rotate to At this time, the claw portion 491 of the drive ring 49 engages with the concave portion 493 of the cam ring 486 to rotate the cam ring 486 counterclockwise. On the other hand, as described above, since the cam follower ring 485 does not rotate, when the cam ring 486 rotates counterclockwise, the relative rotational position between the cam 486a and the cam follower 485a changes, and the cam 486a moves to the top 486d of the cam follower 485a (FIG. 13) Put on. As a result, the cam follower 485 and the lens frame 481 move in the direction away from the base 46 along the optical axis X. As a result, the lens 482 moves away from the imaging element 462 in the direction of the optical axis X. Move to When energization by the energization circuit 7 is stopped, the drive ring 49 rotates clockwise (in the direction of arrow B in FIG. 14A). At this time, the claw portion 491 and the recess 493 do not engage with each other, so the cam ring 486 rotates. do not do. Therefore, the cam follower 485 and the lens frame 481 do not move straight, and the lens 482 is held at the close-up position. Note that the angle at which the cam ring 486 rotates due to the displacement of the shape memory alloy wire 2 corresponds to an angle by which the cam follower 485a is relatively moved from the bottom 486b to the top 486d (FIG. 13) of the cam 486a. .

  When the shape memory alloy wire 2 is energized again by the energization circuit 7 and the drive ring 49 and the cam ring 486 are rotated counterclockwise, the cam follower 485a passes from the top 486d of the cam 486a through the inclined portion 486e (see FIG. 4). Returning to 13), the cam follower ring 485 and the lens frame 481 move straight along the direction of the optical axis X in the direction approaching the base 46. That is, the lens 482 returns from the close-up position to the standard position. When the energization by the energization circuit 7 is stopped, the drive ring 49 returns to the original rotation position, but the cam ring 486 does not rotate, and thus the lens 482 is held at the standard position. In this way, by passing a current through the shape memory alloy wire 2 by the energization circuit 7, the lens 482 can be moved in the direction of the optical axis X, and a focal position suitable for standard photography and close-up photography can be obtained. Further, the lens 482 can be held at the close-up position or the standard position with the energization by the energization circuit 7 stopped.

  In general, the imaging apparatus is configured by arranging a cylindrical lens frame 481 on a square imaging element frame (base 46). Since the shape memory alloy wire 2 can be disposed in the space around the lens frame 481, the surplus space of the image sensor frame can be used, and the image pickup apparatus can be downsized.

  In the drive device 40 described above, the cam follower 485a is formed on the cam follower ring 485, and the cam 486a is formed on the cam ring 486. However, as shown in FIG. 15, the cam ring 486 is formed on the bottom surface of the cam follower ring 485. A cam follower 485a may be formed. The number of cam followers 485a and cams 486a may be three or more, and can be set as appropriate according to the rotation angle of the drive ring 49 and the like. Further, the purpose of driving the lens 482 is not limited to switching between the close-up position and the standard position, and may be anything that drives the lens 482 with the same configuration. Further, the guide groove 81 (FIG. 3) or the stepped portion 82 (FIG. 4) described in the modification of the first embodiment may be provided in the drive ring 49.

  As described above, according to the driving device 40 according to the fifth embodiment, the shape memory alloy wire 2 is arranged using the surplus space in the imaging device such as a camera, and the lens is driven using this. Can do. Therefore, the imaging device can be further downsized.

Embodiment 6 FIG.
16 and 17 are a cross-sectional view and a perspective view showing the configuration of the driving apparatus 50 according to Embodiment 6 of the present invention. In the driving device 50 according to the sixth embodiment, the rotating member described in the first embodiment is applied to a cam ring that moves a lens 582 of an imaging device (for example, a camera) in the direction of the optical axis X. In FIG. 16 and FIG. 17, the same reference numerals are given to components common to the drive device 1 according to the first embodiment.

  As shown in FIG. 16, the drive device 50 includes a cam ring 58 that is a substantially cylindrical member whose central axis is substantially parallel to the optical axis X of the lens 582. The cam ring 58 is supported by an annular holding portion 563 formed on the base 56 so as to be rotatable about the optical axis X. A cam groove 586 (FIG. 17) for moving the lens 582 in the direction of the optical axis X is formed in the cam ring 58. The base 56 is formed with a hole 561 through which the light beam collected by the lens 582 passes. An imaging element 562 is disposed below the hole 561 of the base 56 and at an image formation position by the lens 582.

  A lens frame 581 that holds the lens 582 is provided inside the cam ring 58. A pair of guide shafts 587 and 588 extending in the direction of the optical axis X is provided inside the lens frame 581. The guide shafts 587 and 588 are held at both ends in the axial direction by an annular member 564 and a base 56 provided on the upper side of the cam ring 58 (on the side opposite to the base 56). The lens frame 581 has a guide portion 583 slidably engaged with the guide shaft 587, and is thereby guided to move in the direction of the optical axis X. Further, the lens frame 581 is prevented from rotating around the guide shaft 587 of the lens frame 581 by sandwiching the guide shaft 588 with a rotation stop portion 584 having a bifurcated tip. The lens frame 581 has a cam pin 585 that engages with the cam groove 586 of the cam ring 58, and the lens frame 581 moves in the direction of the optical axis X along the guide shafts 587 and 588 by the rotation of the cam ring 58. It is configured to

  One end of the shape memory alloy wire 2 is fixed to a fixing member 6 a erected on the base 56, and is wound around the outer periphery of the cam ring 58. The other end of the shape memory alloy wire 2 is fixed to a fixing portion 53 that protrudes from the outer peripheral surface of the cam ring 58. One end of the spring 4 is fixed to the fixing portion 53, and the other end of the spring 4 is fixed to a fixing member 6 b erected adjacent to the fixing member 6 a. A specific example of the method of fixing the shape memory alloy wire 2 and the spring 4 is as described in the first embodiment.

  In the sixth embodiment, when a current is supplied to the shape memory alloy wire 2 by the energization circuit 7, the shape memory alloy wire 2 contracts and rotates the cam ring 58 clockwise (indicated by an arrow CW in FIG. 17). As the cam ring 58 rotates, the lens frame 581 moves along the guide shafts 587 and 588 in a direction away from the base 56 due to the engagement between the cam groove 586 and the cam pin 585. As a result, the lens 582 moves in the direction away from the image sensor 562 along the direction of the optical axis X. Further, when the energization by the energization circuit 7 is stopped, the shape memory alloy wire 2 is extended, so that the rotating member 58 is rotated counterclockwise (indicated by an arrow CCW in FIG. 17) by the urging force of the spring 4, and the lens frame 581 is It moves along the guide shafts 587 and 588 in the direction approaching the base 56. As a result, the lens 582 moves along the optical axis X in a direction approaching the image sensor 562 and returns to the initial position. Thus, the lens 582 can be moved along the direction of the optical axis X using the shape memory alloy wire 2.

  In the above description, the structure of the rotating member 8 described in the first embodiment (FIG. 1) is applied to the cam ring 58. However, the structure of the rotating member described in the second to fourth embodiments is applied to the cam ring 58. You may apply. Further, the guide groove 81 (FIG. 3) or the stepped portion 82 (FIG. 4) described in the modification of the first embodiment may be provided in the rotating member 58.

  As described above, according to the driving device 50 according to the sixth embodiment, it is possible to drive the lens by the cam ring using the shape memory alloy wire arranged around the cam ring, and the imaging device. Can be further reduced in size.

  The present invention drives an object using a shape memory alloy such as automatic rotation of a dial provided in a portable device (for example, a mobile phone terminal) or driving of a lens of a small camera mounted on the portable device. Applicable to usage.

It is a perspective view which shows the drive device which concerns on Embodiment 1 of this invention. It is a top view for demonstrating operation | movement of the drive device which concerns on Embodiment 1 of this invention. It is a perspective view which shows the drive device which concerns on the 1st modification of Embodiment 1 of this invention. It is a perspective view which shows the drive device which concerns on the 2nd modification of Embodiment 1 of this invention. It is a perspective view which shows the drive device which concerns on Embodiment 2 of this invention. It is the perspective view (a) and top view (b)-(d) which show the example of the specific shape of the rotating member of the drive device concerning Embodiment 2 of this invention. It is a perspective view for demonstrating the experimental method regarding the specific shape of the drive device which concerns on Embodiment 2 of this invention. It is a graph which shows the experimental result regarding the specific shape of the drive device concerning Embodiment 2 of this invention. It is a perspective view which shows the drive device which concerns on Embodiment 3 of this invention. It is the perspective view (a) which shows the drive device which concerns on Embodiment 4 of this invention, and the perspective view (b) which expands and shows a part. They are sectional drawing (a) which shows the drive device which concerns on Embodiment 4 of this invention, and sectional drawing (b) (c) for demonstrating the operation | movement. It is a top view which expands and shows a part of drive device concerning Embodiment 4 of this invention. It is sectional drawing which shows the drive device which concerns on Embodiment 5 of this invention. It is the exploded perspective view (a) which shows the drive device concerning Embodiment 5 of this invention, and the figure (b) (c) (d) which expands and shows the component, respectively. It is sectional drawing which shows the drive device which concerns on the modification of Embodiment 5 of this invention. It is sectional drawing which shows the drive device which concerns on Embodiment 6 of this invention. It is a perspective view which shows the drive device which concerns on Embodiment 6 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Drive device, 2 Shape memory alloy wire, 3 Fixing part, 4 Energizing member, 6 Base, 6a, 6b Fixing member, 7 Current supply circuit, 8 Rotating member, 1A, 1B Drive apparatus, 81 Guide groove, 82 Step part , 10 driving device, 15 contact portion, 18 rotating member, 20 driving device, 23a, 23b fixing portion, 28 rotating member, 30 driving device, 33 fixing portion, 38 rotating member, 381 recess, 39 driving ring, 391 claw portion, 392 Spring, 40 drive device, 46 base, 462 imaging device, 481 lens frame, 482 lens, 485 cam follower ring, 486 cam ring, 49 drive ring, 491 claw portion, 493 recess, 50 drive device, 53 fixing portion, 56 base Stand, 562 imaging device, 58 cam ring, 581 lens frame, 582 lens, 584 rotation stopper, 585 cam pin, 586 cam groove.

Claims (17)

A bendable long shape memory alloy member;
A rotating member that obtains a rotational output from the displacement of the shape memory alloy member;
An urging member for urging the shape memory alloy member in a direction to suppress displacement;
A base that supports the shape memory alloy member, the rotating member, and the biasing member;
The drive device, wherein the shape memory alloy member is wound around the rotating member. The drive device according to claim 1, wherein the shape memory alloy member is directly wound around an outer peripheral surface of the rotating member. The rotating member has a fixing portion for fixing one end of the shape memory alloy member, and the other end of the shape memory alloy member is fixed to the base. The drive device described in 1. The drive device according to claim 3, wherein one end of the urging member is fixed to the fixing portion of the rotating member, and the other end of the urging member is fixed to the base. The drive device according to claim 1, wherein the rotating member has a plurality of contact portions that contact the shape memory alloy member. The drive device according to claim 5, wherein the contact portion is a tip of a protruding portion that protrudes radially outward of the rotating member. The driving device according to claim 5, wherein the contact portion has a curved surface that contacts the shape memory alloy member. The drive device according to any one of claims 1 to 7, wherein the rotating member has a groove portion or a step portion for preventing displacement of the shape memory alloy member. The rotating member has a first fixing portion for fixing one end of the shape memory alloy member and a second fixing portion for fixing one end of the biasing member at different positions. Item 9. The driving device according to any one of Items 1 to 8. A driving member around which the shape memory alloy member is wound around the rotating member,
The drive device according to any one of claims 1 to 9, wherein the rotary member is configured to rotate via the drive member by displacement of the shape memory alloy member. When the driving member rotates in one direction, the rotating member is driven to rotate in the same direction,
The driving device according to claim 10, wherein the rotating member is configured not to rotate when the driving member rotates in the reverse direction. One of the rotating member and the driving member has a convex portion, and the other has a concave portion that can be engaged with the convex portion,
The convex portion and the concave portion are engaged when the driving member rotates in one direction, and the convex portion and the concave portion are not engaged when the driving member rotates in the opposite direction. The drive device according to claim 11. The drive device according to any one of claims 1 to 12, wherein the rotating member is a part of a cam mechanism that moves a lens frame that holds a lens in an optical axis direction of the lens. The rotating member is a first member belonging to the cam mechanism;
A second member belonging to the cam mechanism is attached to the lens frame,
A cap for covering the lens frame is provided on the base,
A spring is provided in the cap for pressing the lens frame toward the base and maintaining the engaged state of the first and second members.
Forming an opening in the base for allowing the luminous flux of the lens to pass through,
The drive device according to claim 13, wherein an imaging element is disposed at a position where the emitted light beam that has passed through the opening is incident. The drive device according to claim 14, wherein the lens frame and the second member respectively have screw portions that are screwed together. The drive device according to any one of claims 1 to 12, wherein the rotating member is a cam ring. The cam ring has a cam groove;
The movable member which is a movable member which can move to the direction of the rotating shaft of the said cam ring, and has a cam follower engaged with the said cam groove inside the said cam ring was provided. The drive device described.

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