WO2010109834A1

WO2010109834A1 - Actuator, drive device, lens unit, image-capturing device, and operation method for actuator

Info

Publication number: WO2010109834A1
Application number: PCT/JP2010/001980
Authority: WO
Inventors: 英二松川
Original assignee: 株式会社ニコン
Priority date: 2009-03-24
Filing date: 2010-03-19
Publication date: 2010-09-30

Abstract

An actuator having an increased output. An actuator configured to move a mover is provided with a driver disposed so as to be able to make contact with the mover, and also with an electromechanical conversion section which has displacement sections arranged side by side in the movement direction of the mover and displaced at different phases in the direction crossing the movement direction of the mover when supplied with electric power and which, by means of the displacement of the displacement sections, causes an end of the driver, said end being located on the mover side, to move rectilinearly in the movement direction of the mover with the end in contact with the mover.

Description

Actuator, drive device, lens unit, imaging device, and operation method of actuator

The present invention relates to an actuator, a drive device, a lens unit, an imaging device, and an operation method of the actuator.

There has been known an actuator including an elastic vibration body provided with a protrusion and a pair of columnar supports that include an electro-mechanical energy conversion element and support the elastic vibration body (see, for example, Patent Document 1). In the actuator, the protrusions are elliptically moved by expanding and contracting the pair of columnar supports in the axial direction with mutually different phases.
Patent Document 1 Japanese Unexamined Patent Application Publication No. 2007-185056

In the above actuator, the tip of the protrusion is displaced in the moving direction of the mover while being displaced toward the mover, so that the contact pressure between the protrusion and the mover changes. Here, the change in the contact pressure causes a slip between the protrusion and the moving member, and this slip generates frictional heat. Therefore, the efficiency of motion transmission from the protrusion to the mover is reduced.

In order to solve the above problems, as a first embodiment of the present invention, an actuator for moving a moving element, which is arranged in a moving direction of the moving element, and a driving element arranged to be able to contact the moving element, And a plurality of displacement portions that are displaced at different phases in a direction intersecting with the moving direction of the moving element by being supplied with electric power, and the moving element in the driving element is displaced by the displacement of the plurality of moving parts. And an electromechanical converter that linearly moves in the moving direction of the movable element in a state in which the end of the movable element is in contact with the movable element.

Further, as a second embodiment of the present invention, a driving element arranged so as to be able to contact the moving element, and a moving element arranged side by side in the moving direction of the moving element and supplied with electric power, An operating method of an actuator having a plurality of displacement portions that are displaced at different phases in a crossing direction, and moving the moving element in the movement direction by displacement of the plurality of displacement portions, wherein the plurality of displacement portions are By displacing the actuator, there is provided an operating method of an actuator that linearly moves in the moving direction of the moving element in a state where the end of the moving element in the driving element is in contact with the moving element.

Note that the summary of the invention described above does not enumerate all necessary features, and sub-combinations of these feature groups can also be inventions.

It is a perspective view showing motor 101 provided with actuator 100 concerning one embodiment. 1 is an exploded perspective view showing a motor 101. FIG. 2 is a side sectional view showing a motor 101. FIG. FIG. 4 is a sectional view taken along line 4-4 of FIG. 2 is a perspective view showing an actuator 100. FIG. 5 is a graph for explaining an operation method of the actuator 100. 5 is a graph for explaining a comparative example of an operation method of the actuator 100. 6 is a side view showing an actuator 200 according to a modification of the actuator 100. FIG. 6 is a graph for explaining an operation method of the actuator 200. 6 is a graph for explaining a modification of the operation method of the actuator 100. 1 is a side cross-sectional view illustrating a schematic configuration of an imaging apparatus 700 including a motor 101. FIG. 3 is a perspective view showing the inside of a lens unit 300 including an actuator 100. FIG.

Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the claimed invention, and all combinations of features described in the embodiments are invented. It is not always essential to the solution.

FIG. 1 is a perspective view showing a motor 101 including an actuator 100 according to an embodiment. For convenience of explanation, the drive output side in the axial direction of the rotating shaft 110 is referred to as an output side, and the opposite side is referred to as a non-output side. Further, the case where the motor 101 is viewed from the axial direction of the rotating shaft 110 (sometimes referred to as the rotating shaft direction) will be described in plan view, and the case where the motor 101 is viewed from the radial direction of the rotating shaft 110 will be described as side view.

As shown in these drawings, the motor 101 includes a rotating shaft 110, a nut 210, a mounting plate 120, a biasing member 130, a washer 230, a rotor 140, three rotors arranged in order from the output side along the rotating shaft 110. An actuator 100, a base 190, and a nut 220 are provided. The mounting plate 120 is formed in a disk shape, and the rotating shaft 110 is inserted through the axis. Further, the mounting plate 120 is formed with a pair of U-shaped fastening holes 122 symmetrically with respect to the axis, and the mounting plate 120 is fastened by a fastener such as a screw inserted through the fastening hole 122. And fastened to a device that uses the motor 101 as a drive source.

The rotor 140 is formed in a disk shape, and the rotating shaft 110 is inserted through the shaft center. A gear portion 144 is formed at the output side end of the rotor 140. An example of the urging member 130 is a compression coil spring shown in the figure, and the rotating shaft 110 is inserted therethrough. The actuator 100 includes a stator 150, an electromechanical converter 160, a pair of flexible printed

wiring boards

170 and 172, and a base 180.

The base 180 is a rectangular plate-like member and is screwed to the base 190. The electromechanical conversion unit 160 includes a first electromechanical conversion unit 161 and a second electromechanical conversion unit 162. The first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 are stacked piezoelectric elements in which piezoelectric elements are stacked in the rotation axis direction, and expand and contract in the stacking direction when a drive voltage is supplied. The first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 are arranged side by side in the longitudinal direction of the base 180. The pair of flexible printed

wiring boards

170 and 172 are arranged side by side in the longitudinal direction of the base 180, and the flexible printed wiring board 170 is sandwiched between the base 180 and the first electromechanical converter 161, The plate 172 is sandwiched between the base 180 and the second electromechanical converter 162.

The stator 150 is formed of an elastic material, and includes a rectangular plate-like base portion 152 and a protruding portion 154 that protrudes from a central portion in the longitudinal direction of the base portion 152. One end of the base portion 152 in the longitudinal direction is joined to the upper end surface of the first electromechanical converter 161, and the other end of the base portion 152 in the longitudinal direction is joined to the upper end surface of the second electromechanical converter 162. . Further, the protrusion 154 protrudes from the base portion 152 toward the rotor 140.

The flexible printed wiring board 170 supplies an alternating drive voltage to the first electromechanical converter 161 to expand and contract the first electromechanical converter 161 in the rotation axis direction. In addition, the flexible printed wiring board 172 supplies an alternating drive voltage to the second electromechanical converter 162 to expand and contract the second electromechanical converter 162 in the direction of the rotation axis.

FIG. 2 is an exploded perspective view showing the motor 101. As shown in this figure, screw portions 112 into which

nuts

210 and 220 are screwed are formed at both ends in the axial direction of the rotating shaft 110, and a disk-shaped flange portion 114 having an enlarged diameter is formed between them. It is formed. The nut 210, the mounting plate 120, the biasing member 130, the washer 230, and the rotor 140 are arranged on the output side with respect to the flange portion 114, while the base 190 and the nut 220 are on the non-output side with respect to the flange portion 114. Arranged. Further, the three actuators 100 are arranged between the rotor 140 and the base 190 so as to surround the rotating shaft 110. Further, the rotor 140 is rotatably supported by the rotating shaft 110 via the bearing 142.

FIG. 3 is a side sectional view showing the motor 101. As shown in this figure, the mounting plate 120, the biasing member 130, the washer 230, the rotor 140, the actuator 100, and the base 190 are fastened in the direction of the rotation axis by

nuts

210 and 220. Here, the urging member 130 is elastically contracted in the rotation axis direction, and the rotor 140 is pressed against the actuator 100 via the washer 230.

4 is a cross-sectional view taken along line 4-4 of FIG. As shown in this figure, the three actuators 100 are arranged around the rotation axis 110 while being shifted by 2π / 3, and the space surrounded by these is a triangle in plan view. The three protrusions 154 are arranged around the rotation axis 110 while being shifted by 2π / 3.

FIG. 5 is a perspective view showing the actuator 100. As shown in this figure, in the actuator 100, a gap 163 is provided between the first electromechanical converter 161 and the second electromechanical converter 162, and the first electromechanical converter 161 and the second electric machine The converter 162 is separated from each other in a direction orthogonal to the expansion / contraction direction (that is, the arrangement direction).

Also, a rectangular groove 153 that bisects the base portion 152 in the longitudinal direction is formed at the longitudinal center of the base portion 152 of the stator 150. The groove 153 extends over the entire width direction of the base portion 152 and is formed so as to overlap with the gap 163 between the first electromechanical converter 161 and the second electromechanical converter 162 in the rotation axis direction. Has been. For this reason, the whole longitudinal direction one end side (it may be called the base part 1521) of the base part 152 is joined to the whole end surface of the 1st electromechanical conversion part 161, and the longitudinal direction other end side (base) of the base part 152 is obtained. The entire portion 1522 may be joined to the entire end surface of the second electromechanical transducer 162.

Also, the groove 153 extends through the base portion 152 to the base end portion of the protruding portion 154 in the depth direction. Thus, a pair of

leg portions

156 and 157 that are divided into two in the longitudinal direction of the base portion 152 by the groove 153 are formed at the base end portion of the projection portion 154. The leg portion 156 extends from the end of the base portion 1521 on the groove 153 side to the opposite side of the first electromechanical transducer 161. Further, the leg portion 157 extends from the end portion of the base portion 1522 on the groove 153 side to the opposite side of the second electromechanical conversion portion 162. In other words, the protruding portion 154 is supported on the base portion 152 by a U-shaped base end portion including a pair of

leg portions

156 and 157.

Further, a wave shaper 175 is connected to the flexible printed

wiring boards

170 and 172 via

drivers

171 and 173, respectively. The driver 171 applies the drive voltage whose waveform has been shaped by the waveform shaper 175 to the first electromechanical converter 161. In addition, the driver 173 applies the drive voltage whose waveform is shaped by the waveform shaper 175 to the second electromechanical converter 162.

Next, the operation in this embodiment will be described. The upper part (a) of FIG. 6 is a graph showing a drive voltage waveform applied to the first electromechanical conversion unit 161 and a drive voltage waveform applied to the second electromechanical conversion unit 162. Further, the middle stage (b) of this figure shows the displacement in the rotation axis direction (sometimes referred to as longitudinal displacement) of the tip portion of the projection 154 and the displacement in the rotation direction of the rotor 140 at the tip portion of the projection 154 (referred to as lateral displacement). It is a graph which shows the relationship with a case. Further, the lower part (c) in the figure is a graph showing the relationship between the longitudinal displacement of the tip part of the protrusion 154 and time.

The waveform of the alternating voltage (A phase voltage) applied to the first electromechanical converter 161 indicated by a solid line in the upper graph (a) is represented by sin (ωt) + Asin (nωt). In addition, the waveform of the alternating voltage (phase B voltage) applied to the second electromechanical converter 162 indicated by a broken line in the upper graph (a) is represented by sin (ωt + δθ) + Asin (nωt + δθ). Here, ω is ω = 2πf, and f represents a frequency. T is time, A is a constant of −1 <A <0, n is a positive integer, and δθ is a phase. In this embodiment, A is −0.125, n is 3, and δθ is −π / 2.

That is, the waveform of the AC voltage applied to the first electromechanical conversion unit 161 is a waveform obtained by adding sin frequency (3t) to sin (ωt). The waveform of the AC voltage applied to the second electromechanical conversion unit 162 is a waveform obtained by adding sin frequency (3 t frequency modulation) to sin (ωt−π / 2).

FIG. 7 is a graph for explaining a comparative example of the operation method of the actuator 100. In the comparative example, as shown by the solid line in the upper graph (a), the first electromechanical converter 161 is applied with the driving voltage (A phase voltage) of sin (ωt), and the upper graph (a). As shown by a broken line in FIG. 6, a driving voltage (B phase voltage) of sin (ωt−π / 2) is applied to the second electromechanical conversion unit 162.

As shown in the upper graph of FIG. 6A, in the present embodiment, the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 are contracted to the maximum when the drive voltage is 0 V, and driven. When the voltage is the maximum value (for example, 50 V), the voltage is extended to the maximum.

At t = 0 (θ = 0), the drive voltage applied to the first electromechanical conversion unit 161 becomes a median value (for example, 25 V) between 0 V and the maximum value, and is applied to the second electromechanical conversion unit 162. The drive voltage becomes 0V. In this state, the expansion amount of the first electromechanical conversion unit 161 is a median value between 0 and the maximum value, and the expansion amount of the second electromechanical conversion unit 162 is 0. For this reason, the projection part 154 takes the attitude | position which inclines to the 2nd electromechanical conversion part 162 side.

At t = 10 (θ = π / 2), the drive voltage applied to the first electromechanical converter 161 is the maximum value, and the drive voltage applied to the second electromechanical converter 162 is the median value. In this state, the extension amount of the first electromechanical conversion unit 161 is maximized, while the extension amount of the second electromechanical conversion unit 162 is a median value between 0 and the maximum value. For this reason, the projection part 154 takes the attitude | position which inclines to the 2nd electromechanical conversion part 162 side.

In the present embodiment, when transitioning from t = 0 to t = 10, the protrusion 154 is provided on the side of the second electromechanical conversion unit 162 by the action of the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162. Maintained in a tilted position. The protrusion 154 is displaced toward the rotor 140 when the first electromechanical converter 161 and the second electromechanical converter 162 both increase the extension amount. On the other hand, also in the comparative example, when transitioning from t = 0 to t = 10, the protrusion 154 is similarly displaced toward the rotor 140 in a posture inclined toward the second electromechanical conversion unit 162.

At t = 15 (θ = 3π / 4), the drive voltage applied to the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 is the same value between the median and the maximum value. In this state, the first electromechanical converter 161 and the second electromechanical converter 162 are extended by the same amount. For this reason, the projection part 154 takes a posture without inclination. On the other hand, also in the comparative example, at t = 15, the drive voltage applied to the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 becomes the same value between the median and the maximum value, and the protrusion 154 Take a posture without tilt.

Here, in this embodiment, the drive voltage applied to the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 is obtained by adding the triple frequency modulation to the drive voltage in the comparative example. Thereby, from t = 10 to t = 15, the amount of voltage decrease of the first electromechanical converter 161 in the present embodiment is larger than that in the comparative example, and the second electromechanical converter 162 in the present embodiment. The amount of increase in voltage is small compared to the comparative example. Therefore, at the time of t = 15, the longitudinal displacement amount of the tip portion of the protrusion 154 in this embodiment is smaller than that in the comparative example.

That is, as shown in the lower graph (c), the height of the tip of the protrusion 154 in this embodiment is lower than that in the comparative example. Further, when transitioning from t = 10 to t = 15, the height of the tip of the protrusion 154 changes at a constant level.

Next, at t = 20 (θ = π), the drive voltage applied to the first electromechanical conversion unit 161 becomes the median value, and the drive voltage applied to the second electromechanical conversion unit 162 becomes the maximum value. In this state, the extension amount of the first electromechanical conversion unit 161 is the median value, and the extension amount of the second electromechanical conversion unit 162 is the maximum value. For this reason, the protrusion part 154 takes the attitude | position which inclines to the 1st electromechanical conversion part 161 side. On the other hand, also in the comparative example, the protrusion 154 is inclined toward the first electromechanical conversion unit 161.

Here, from t = 15 to t = 20, the amount of decrease in the voltage of the first electromechanical converter 161 in the present embodiment is smaller than that in the comparative example due to the above triple frequency modulation. The amount of voltage increase of the second electromechanical converter 162 in the embodiment is larger than that in the comparative example. Therefore, at the time of t = 20, the longitudinal displacement amount of the tip portion of the protrusion 154 in this embodiment is smaller than that in the comparative example.

That is, as shown in the lower graph (c), the height of the tip of the protrusion 154 in this embodiment is higher than that of the comparative example. Further, when transitioning from t = 15 to t = 20, the height of the tip of the protrusion 154 changes at a constant level.

Next, at t = 30 (θ = 3π / 2), the drive voltage applied to the first electromechanical converter 161 is 0V, and the drive voltage applied to the second electromechanical converter 162 is the median value. . In this state, the extension amount of the first electromechanical converter 161 is 0, and the extension amount of the second electromechanical converter 162 is the median value. For this reason, the protrusion part 154 takes the attitude | position which inclines to the 1st electromechanical conversion part 161 side.

Here, when transitioning from t = 20 to t = 30, the protrusion 154 is inclined toward the first electromechanical conversion unit 161 by the action of the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162. Maintained in the correct posture. On the other hand, the protrusion 154 has an attitude that is inclined toward the first electromechanical conversion unit 161 in an attitude that the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 contract by the same amount. Displace to 160 side. On the other hand, similarly in the comparative example, the protrusion 154 is displaced toward the electromechanical conversion unit 160 in a posture inclined toward the first electromechanical conversion unit 161.

Next, at t = 35 (θ = 7π / 4), the drive voltage applied to the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 becomes the same value between 0 V and the median value. In this state, the first electromechanical converter 161 and the second electromechanical converter 162 are extended by the same amount. For this reason, the projection part 154 takes a posture without inclination. On the other hand, also in the comparative example, at t = 35, the drive voltage applied to the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 becomes the same value between 0 V and the median, and the protrusion 154 is Take a posture without tilting.

Here, due to the triple frequency modulation described above, the amount of voltage increase of the first electromechanical converter 161 in the present embodiment is larger than that in the comparative example, and the second electromechanical converter 162 in the present embodiment The amount of voltage decrease is small compared to the comparative example. Therefore, at the time of t = 35, the longitudinal displacement amount of the tip portion of the protrusion 154 in this embodiment is larger than that in the comparative example.

That is, as shown in the lower graph (c), the height of the tip of the protrusion 154 in this embodiment is higher than that of the comparative example. Further, when transitioning from t = 30 to t = 35, the height of the tip of the protrusion 154 changes at a constant level.

And when it changes from t = 35 to t = 40, the projection part 154 returns to the state of the above-mentioned t = 0.

Here, the tip of the protrusion 154 is displaced toward the rotor 140 while being tilted toward the second electromechanical converter 162 by the action of the first electromechanical converter 161 and the second electromechanical converter 162. After that, it swings toward the first electromechanical converter 161 side. Here, when the tip of the protrusion 154 swings from the second electromechanical converter 162 side to the first electromechanical converter 161 side, the tip of the protrusion 154 is linear along the rotational direction of the rotor 140. Move to.

And the front-end | tip part of the projection part 154 is the side of the electromechanical conversion part 160 in the state inclined to the 1st electromechanical conversion part 161 side by the effect | action of the 1st electromechanical conversion part 161 and the 2nd electromechanical conversion part 162. After the displacement, the second electromechanical converter 162 swings to the side. Here, when the tip of the protrusion 154 swings from the first electromechanical conversion unit 161 side to the second electromechanical conversion unit 162 side, the tip of the protrusion 154 extends in the opposite direction to the direction opposite to the rotation direction of the rotor 140. Move linearly.

That is, the tip portion of the protrusion 154 circulates along a rectangular peripheral circuit by the action of the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162. The circumferential circuit includes a forward path that extends linearly in the rotational direction of the rotor 140 and a U-shape that bypasses the electromechanical conversion unit 160 from the upstream end portion to the downstream end portion of the forward path. With a return path.

As a result, the vertical movement of the tip portion of the projection portion 154 is compared when the tip portion of the projection portion 154 is in contact with the rotor 140 and is displaced in the rotational direction of the rotor 140 to apply thrust to the rotor 140. Suppressed compared to the example. Therefore, compared with a comparative example, the fluctuation | variation of the contact pressure of the front-end | tip part of the projection part 154 and the rotor 140 can be suppressed, and generation | occurrence | production of frictional heat can be suppressed. Therefore, compared with the comparative example, the motion transmission efficiency from the protrusion 154 to the rotor 140 can be improved, and thus the output of the actuator 100 can be improved efficiently.

In addition, after the tip portion of the protrusion 154 is linearly displaced toward the rotor 140 in a posture inclined in the direction opposite to the rotation direction of the rotor 140, it linearly moves along the rotation direction in the rotation direction of the rotor 140. To do. Thereby, when the front-end | tip part of the projection part 154 moves to the rotation direction of the rotor 140 compared with a comparative example, the effective moving distance which contributes to the thrust generation of the rotor 140 becomes long. Therefore, compared to the comparative example, the motion transmission efficiency from the protrusion 154 to the rotor 140 can be further improved, and thus the output of the actuator 100 can be further improved more efficiently. Also, it is not necessary to use the resonance of the entire system of the motor 101 by expanding the amplitude of the protrusion 154 in the lateral direction by the action of the electromechanical conversion unit 160. Therefore, the actuator 100 can be driven at a frequency different from the resonance frequency of the entire motor 101 system.

FIG. 8 is a side view showing an actuator 200 according to a modified example of the actuator 100. As shown in this figure, in the actuator 200 according to this embodiment, the upper surface of the base 180 is inclined toward the rotor 140 toward the rotation direction of the rotor 140. The second electromechanical converter 162 and the first electromechanical converter 161 erected on the upper surface of the base 180 are arranged side by side in the rotational direction in this description order.

For this reason, the first electromechanical converter 161 and the second electromechanical converter 162 are inclined in the direction opposite to the rotational direction of the rotor 140 from the base 180 side to the rotor 140 side. Further, the first electromechanical conversion unit 161 is arranged closer to the rotor 140 side than the second electromechanical conversion unit 162. Further, the base portion 152 of the stator 150 is inclined toward the rotor 140 in the rotational direction, and the protrusion 154 is inclined in the direction opposite to the rotational direction from the proximal end side to the distal end side.

9A is a graph showing a drive voltage waveform applied to the first electromechanical conversion unit 161 and a drive voltage waveform applied to the second electromechanical conversion unit 162. Further, the lower part (b) of this figure is a graph showing the relationship between the longitudinal displacement of the tip of the projection 154 and the lateral displacement of the tip of the projection 154.

The waveform of the alternating voltage (A phase voltage) applied to the first electromechanical converter 161 indicated by a solid line in the upper graph (a) is represented by sin (ωt) + Asin (nωt). In addition, the waveform of the alternating voltage (phase B voltage) applied to the second electromechanical converter 162 indicated by a broken line in the upper graph (a) is represented by sin (ωt + δθ) + Asin (nωt + δθ). In this embodiment, A is -0.15, n is 2, and δθ is -2π / 3.

That is, the waveform of the AC voltage applied to the first electromechanical converter 161 is a waveform obtained by adding double frequency modulation to sin (ωt). The waveform of the AC voltage applied to the second electromechanical converter 162 is a waveform obtained by adding double frequency modulation to sin (ωt−2π / 3).

As shown in the upper graph (a), at t = 0, the drive voltage applied to the first electromechanical conversion unit 161 is a median value between 0 V and the maximum value, and the second electromechanical conversion unit 162 The drive voltage applied to is about 0V. For this reason, the projection part 154 takes the attitude | position inclined toward the 2nd electromechanical conversion part 162 side.

And the drive voltage applied to the 1st electromechanical conversion part 161 and the 2nd electromechanical conversion part 162 rises with progress of time. As a result, the protrusion 154 is displaced toward the rotor 140 while being inclined toward the second electromechanical converter 162.

And while the drive voltage applied to the second electromechanical converter 162 is increasing, the drive voltage applied to the first electromechanical converter 161 increases to the maximum value and starts to decrease. Then, when the drive voltage applied to the second electromechanical converter 162 increases to the maximum value, the drive voltage starts to decrease, and after that, the drive voltage applied to the first electromechanical converter 161 decreases to 0V and increases. Roll over. For this reason, the protrusion 154 swings from the second electromechanical converter 162 side to the first electromechanical converter 161 side after being displaced to the rotor 140 side.

Here, the decrease amount per unit time of the drive voltage applied to the first electromechanical conversion unit 161 is larger than the increase amount per unit time of the drive voltage applied to the second electromechanical conversion unit 162. For this reason, when the tip of the protrusion 154 swings from the second electromechanical converter 162 side to the first electromechanical converter 161 side, the contraction speed of the first electromechanical converter 161 is the second electromechanical converter. It becomes faster than the speed at which the conversion unit 162 expands. Further, as shown in the lower graph (b), the tip of the protrusion 154 is displaced in parallel along the direction inclined toward the electromechanical transducer 160 with respect to the lateral displacement direction.

And while the drive voltage applied to the first electromechanical conversion unit 161 is increasing, the drive voltage applied to the second electromechanical conversion unit 162 decreases to 0V and starts to increase. And the drive voltage applied to the 1st electromechanical conversion part 161 and the 2nd electromechanical conversion part 162 becomes a value at the time of t = 0. Therefore, the protrusion 154 swings from the first electromechanical converter 161 side to the second electromechanical converter 162 side while being displaced toward the electromechanical converter 160 side.

Thereby, as shown in the lower graph (b), the tip of the protrusion 154 moves along an isosceles triangular locus. Here, the isosceles triangular trajectory includes a bottom extending along the rotation axis direction on the second electromechanical conversion unit 162 side from the rotation axis, and an isosceles extending from the bottom to the first electromechanical conversion unit 161 side. including.

Here, the first electromechanical converter 161 and the second electromechanical converter 162 are inclined in the direction opposite to the rotational direction of the rotor 140 from the base 180 side to the rotor 140 side. Further, the first electromechanical conversion unit 161 is arranged closer to the rotor 140 side than the second electromechanical conversion unit 162. Further, the base portion 152 of the stator 150 is inclined toward the rotor 140 in the rotational direction, and the protrusion 154 is inclined in the direction opposite to the rotational direction from the proximal end side to the distal end side.

For this reason, when the tip of the protrusion 154 swings from the second electromechanical converter 162 side to the first electromechanical converter 161 side, in the forward path along the rotational direction of the rotor 140 Move linearly. Thus, as in the above-described embodiment, when the tip of the protrusion 154 is in contact with the rotor 140 and is displaced in the rotational direction of the rotor 140 to apply thrust to the rotor 140, the protrusion 154 The vertical movement of the tip is suppressed as compared with the comparative example. Therefore, compared with the comparative example, fluctuations in the contact pressure between the tip of the protrusion 154 and the rotor 140 can be suppressed, and generation of frictional heat can be suppressed. Therefore, compared with the comparative example, the motion transmission efficiency from the protrusion 154 to the rotor 140 can be improved, and thus the output of the actuator 200 can be improved efficiently.

Next, another embodiment of the driving method of the actuator 100 will be described. The upper part (a) of FIG. 10 is a graph showing a drive voltage waveform applied to the first electromechanical conversion unit 161 and a drive voltage waveform applied to the second electromechanical conversion unit 162. Further, the middle stage (b) of this figure is a graph showing the relationship between the longitudinal displacement of the tip of the projection 154 and the lateral displacement of the tip of the projection 154. Further, the lower part (c) of the figure is a graph showing the relationship between the longitudinal displacement and lateral displacement of the tip of the protrusion 154 and time.

The waveform of the alternating voltage (A phase voltage) applied to the first electromechanical converter 161 indicated by a solid line in the upper graph (a) is represented by sin (ωt) + Asin (nωt). In addition, the waveform of the alternating voltage (phase B voltage) applied to the second electromechanical converter 162 indicated by a broken line in the upper graph (a) is represented by sin (ωt + δθ) + Asin (nωt + δθ). Here, in the present embodiment, both the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 have n of 2 and δθ of −π / 2, and the first electromechanical conversion unit 161 has A = − In 0.25, the second electromechanical converter 162 has A = 0.25.

That is, the waveform of the AC voltage applied to the first electromechanical converter 161 is a waveform obtained by adding double frequency modulation to sin (ωt). The waveform of the AC voltage applied to the second electromechanical converter 162 is a waveform obtained by adding double frequency modulation to sin (ωt−π / 2). In addition, the drive voltage applied to the first electromechanical converter 161 and the drive voltage applied to the second electromechanical converter 162 are in opposite phases.

At t = 0, the drive voltage applied to the first electromechanical converter 161 and the second electromechanical converter 162 is a median value between 0V and the maximum value. In this state, the expansion amount of the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 is a median value between 0 and the maximum value. For this reason, the projection part 154 takes a posture without inclination.

At t = 8, the drive voltage applied to the first electromechanical converter 161 is the maximum value, and the drive voltage applied to the second electromechanical converter 162 is 0V. In this state, the extension amount of the first electromechanical conversion unit 161 becomes the maximum value, and the extension amount of the second electromechanical conversion unit 162 becomes zero. For this reason, the projection part 154 takes the attitude | position which inclines to the 2nd electromechanical conversion part 162 side.

That is, when transitioning from t = 0 to t = 8, the protrusion 154 tilts toward the second electromechanical converter 162 from the neutral position without tilt. Here, as shown in the middle (b) and lower (c) graphs, the tip of the protrusion 154 moves linearly along the opposite direction in the opposite direction of the rotation direction of the rotor 140.

Then, as shown in the upper graph (a), when the transition from t = 8 to t = 32, the drive voltage applied to the first electromechanical converter 161 decreases to 0 V, while the second electromechanical converter The drive voltage applied to the unit 162 increases to the maximum value. Thereby, the expansion amount of the first electromechanical conversion unit 161 decreases from the maximum value to 0, while the expansion amount of the second electromechanical conversion unit 162 increases from 0 to the maximum value. For this reason, the protrusion 154 swings from the second electromechanical converter 162 side to the first electromechanical converter 161 side. Here, as shown in the middle (b) and lower (c) graphs, the tip of the protrusion 154 moves linearly in the forward direction along the rotational direction of the rotor 140 in the rotational direction.

As shown in the upper graph (a), when the transition from t = 32 to t = 40, the drive voltage applied to the first electromechanical converter 161 increases to the median value, while the second electromechanical conversion is performed. The driving voltage applied to the unit 162 decreases to the median value. As a result, the extension amounts of the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 are both median and return to the state of t = 0. Further, the protrusion 154 swings from the first electromechanical conversion unit 161 side to the neutral position and returns to the state of t = 0.

By the way, from t = 8 to t = 32, the tip of the protrusion 154 linearly moves in the rotation direction of the rotor 140, and then the tip of the protrusion 154 moves linearly in the direction opposite to the rotation direction of the rotor 140. To do. Here, the speed of expansion and contraction of the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 from t = 8 to t = 32 is the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 thereafter. Slower than the speed of stretching. For this reason, the rotor 140 continues to rotate in the rotation direction due to inertial force.

Further, when the tip of the protrusion 154 moves in the rotation direction of the rotor 140, it moves linearly in the forward path along the rotation direction. Thus, as in the above-described embodiment, when the tip of the protrusion 154 is in contact with the rotor 140 and is displaced in the rotational direction of the rotor 140 to apply thrust to the rotor 140, the protrusion 154 The vertical movement of the tip is suppressed as compared with the comparative example. Therefore, compared with the comparative example, fluctuations in the contact pressure between the tip of the protrusion 154 and the rotor 140 can be suppressed, and generation of frictional heat can be suppressed. Therefore, compared with the comparative example, the motion transmission efficiency from the protrusion 154 to the rotor 140 can be improved, and thus the output of the actuator 100 can be improved efficiently.

In this embodiment, since the high-order term component of the modulation function is not added to the drive voltage waveform, as shown in the graphs of FIGS. 6B, 9B, and 10B, the protrusion 154 While the tip portion moves linearly, the tip portion of the protrusion 154 does not change at all in the direction orthogonal to the moving direction of the moving object. Some of the first electromechanical converter 161 and the second electromechanical converter 162 still remain even if the above-described frequency modulation is applied to the drive voltage waveforms. That is, the linear motion includes a motion that still varies even if the frequency modulation is applied to the drive voltage waveforms of the first electromechanical converter 161 and the second electromechanical converter 162.

FIG. 11 is a side sectional view showing a schematic configuration of an imaging apparatus 700 including the motor 101. As shown in this figure, the imaging apparatus 700 includes an optical member 420, a lens barrel 430, a motor 101, an imaging unit 500, and a control unit 550. The lens barrel 430 accommodates the optical member 420.

The motor 101 moves the optical member 420. The imaging unit 500 captures an image formed by the optical member 420. The control unit 550 controls the motor 101 and the imaging unit 500.

The imaging apparatus 700 includes an optical member 420, a lens barrel 430, a lens unit 410 including the motor 101, and a body 460. The lens unit 410 is detachably attached to the body 460 via the mount 450.

The optical member 420 includes a front lens 422, a compensator lens 424, a focusing lens 426, and a main lens 428, which are sequentially arranged from the incident end corresponding to the left side in the drawing. An iris unit 440 is disposed between the focusing lens 426 and the main lens 428.

The motor 101 is arranged in the middle of the lens barrel 430 in the optical axis direction and below the focusing lens 426 having a relatively small diameter. Accordingly, the motor 101 is accommodated in the lens barrel 430 without increasing the diameter of the lens barrel 430. The motor 101 moves the focusing lens 426 forward or backward in the optical axis direction through, for example, a gear train.

The body 460 accommodates optical members including a main mirror 540, a pentaprism 470, and an eyepiece system 490. The main mirror 540 is located between a standby position inclined on the optical path of incident light incident through the lens unit 410 and an imaging position (indicated by a dotted line in the figure) that rises while avoiding incident light. Moving.

The main mirror 540 at the standby position guides most of the incident light to the pentaprism 470 disposed above. Since the pentaprism 470 emits a reflection of incident light toward the eyepiece system 490, the image on the focusing screen can be viewed as a normal image from the eyepiece system 490. The remainder of the incident light is guided to the photometric unit 480 by the pentaprism 470. The photometric unit 480 measures the intensity and distribution of incident light.

A half mirror 492 is arranged between the pentaprism 470 and the eyepiece system 490 to superimpose the display image formed on the finder liquid crystal 494 on the image of the focusing screen. The display image is displayed so as to overlap the image projected from the pentaprism 470.

The main mirror 540 has a sub mirror 542 on the back surface with respect to the incident light incident surface. The sub mirror 542 guides part of the incident light transmitted through the main mirror 540 to the distance measuring unit 530 disposed below. Thereby, when the main mirror 540 is in the standby position, the distance measuring unit 530 measures the distance to the subject. When the main mirror 540 is moved to the photographing position, the sub mirror 542 is also retracted from the optical path of the incident light.

Furthermore, a shutter 520, an optical filter 510, and an imaging unit 500 are sequentially arranged behind the main mirror 540 with respect to incident light. When the shutter 520 is opened, the main mirror 540 moves to the photographing position immediately before the shutter 520 is opened, so that incident light travels straight and enters the imaging unit 500. Thereby, an image formed by incident light is converted into an electric signal. Thereby, the imaging unit 500 captures an image formed by the lens unit 410.

In the imaging device 700, the lens unit 410 and the body 460 are also electrically coupled. Therefore, for example, the autofocus mechanism can be formed by controlling the rotation of the motor 101 in accordance with the distance information to the subject detected by the distance measuring unit 530 on the body 460 side. In addition, a focus aid mechanism can be formed by the distance measuring unit 530 referring to the operation amount of the motor 101. The motor 101 and the imaging unit 500 are controlled by the control unit 550 as described above.

Here, as described above, the output torque of the motor 101 can be increased efficiently. Therefore, since the driving force of the autofocus mechanism can be increased efficiently, it is possible to save power and drive the autofocus mechanism with a high driving force.

Although the case where the focusing lens 426 is moved by the motor 101 has been illustrated, it goes without saying that the opening and closing of the iris unit 440 and the movement of the variator lens of the zoom lens can be driven by the motor 101. Also in this case, by referring to information with the photometric unit 480, the finder liquid crystal 494, etc. via the electrical signal, the motor 101 contributes to automating exposure, execution of the scene mode, execution of bracket photography, and the like.

As described above, the motor 101 can be suitably used for driving a focusing mechanism, a zoom mechanism, a camera shake correction mechanism, and the like in an optical system such as a photographing machine and binoculars. Furthermore, it can be used for power sources such as precision stages, more specifically electron beam lithography equipment, various stages for inspection equipment, moving mechanisms for cell injectors for biotechnology, moving beds for nuclear magnetic resonance equipment, etc. Needless to say, it is not limited to.

FIG. 12 is a perspective view showing the inside of the lens unit 300 including the actuator 100. The lens unit 300 can be attached to the body 460. As shown in this figure, the lens unit 300 includes a focusing lens 426, a lens holding frame 302 that holds the focusing lens 426, and a pair of guide bars 304 that guide the movement of the lens holding frame 302 in the optical axis direction. 306 is arranged. A bearing portion 308 is provided on the left side of the lens holding frame 302, and a pair of front and

rear bearing portions

310 and 312 are provided on the upper right portion of the lens holding frame 302. The guide bar 304 is slidably inserted into the bearing portion 308, and the guide bar 306 is slidably inserted into the bearing

portions

310 and 312.

The bearing portion 310 and the bearing portion 312 are connected by a stay 314 extending in the optical axis direction. A rectangular plate-like moving body 316 whose longitudinal direction is the optical axis direction is suspended below the stay 314 so as to be displaceable in the vertical direction. Further, a leaf spring 318 is disposed between the lower portion of the stay 314 and the moving body 316. The leaf spring 318 biases the moving body 316 downward.

Here, the actuator 100 is disposed below the moving body 316, and the moving body 316 is pressed against the protrusion 154 of the actuator 100 by a leaf spring 318. The actuator 100 is arranged such that the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 are arranged in the optical axis direction. Therefore, when the actuator 100 is operated by the above-described method, a thrust force in the optical axis direction is applied from the protrusion 154 to the moving body 316, and the lens holding frame 302 and the focusing lens 426 are moved in the optical axis direction. Moved. In the lens unit 300, the actuator 200 may be used instead of the actuator 100.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

For example, in the above embodiment, the electromechanical conversion unit 160 is configured by the first electromechanical conversion unit 161 and the second electromechanical conversion unit 162 arranged in the rotation direction of the rotor 140. However, a third electromechanical converter that supports the first electromechanical converter 161 and the second electromechanical converter 162 may be further added. In this case, the longitudinal displacement amount of the entire electromechanical conversion unit 160 can be increased.

In the above embodiment, a piezoelectric element is used as the displacement part of the electromechanical conversion part. However, a lead screw or the like that is linearly moved by a voice coil motor or a DC motor can also be applied.

The execution order of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior”. It should be noted that they can be implemented in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for the sake of convenience, it means that it is essential to carry out in this order. is not.

100 actuator, 101 motor, 110 rotating shaft, 112 screw part, 114 flange part, 120 mounting plate, 122 fastening hole, 130 urging member, 140 rotor, 142 bearing, 144 gear part, 150 stator, 152 base part, 153 Groove, 154 protrusion, 156, 157 leg, 160 electromechanical converter, 161 first electromechanical converter, 162 second electromechanical converter, 163 gap, 170, 172 flexible printed wiring board, 171, 173 driver, 175 Wave shaper, 180 base, 190 base, 200 actuator, 210, 220 nut, 230 washer, 300 lens unit, 302 lens holding frame, 304, 306 guide bar, 308, 310, 312 bearing part, 3 4 stay, 316 moving body, 318 leaf spring, 410 lens unit, 420 optical member, 426 focusing lens, 428 main lens, 430 lens barrel, 440 iris unit, 450 mount, 460 body, 470 pentaprism, 480 photometric unit, 490 eyepiece system, 492 half mirror, 494 finder liquid crystal, 500 imaging unit, 510 optical filter, 520 shutter, 530 ranging unit, 540 main mirror, 542 sub-mirror, 550 control unit, 700 imaging device, 1521 base unit, 1522 base unit

Claims

An actuator for moving the slider,
A driving element arranged so as to be able to contact the moving element;
A plurality of displacement portions that are arranged side by side in the moving direction of the moving element and are displaced at different phases in a direction intersecting with the moving direction of the moving element when electric power is supplied. An electromechanical conversion unit that linearly moves in the moving direction of the moving element in a state where the moving element side end of the driving element is in contact with the moving element;
An actuator comprising:
The electromechanical conversion unit moves the end portion of the moving element in the driver by the displacement of the plurality of displacement portions, the forward path that performs the linear motion, and the electrical path from the downstream end portion to the upstream end portion of the forward path. 2. The actuator according to claim 1, wherein the actuator makes a reciprocating motion along a peripheral circuit including a return path that detours toward the mechanical conversion unit.
The actuator according to claim 2, wherein the peripheral circuit is a polygonal path.
The plurality of displacement parts include a pair of expansion and contraction parts arranged side by side in the moving direction of the mover,
One of the pair of expansion / contraction parts is applied with a driving voltage V1 having a waveform represented by the following expression (1), and the other of the pair of expansion / contraction parts has a driving voltage having a waveform represented by the following expression (2). The actuator according to claim 3, which expands and contracts when V2 is applied.
V1 = sin (ωt) + Asin (n × ωt) (1)
V2 = sin (ωt + δθ) + Asin (n × (ωt + δθ)) (2)
However, ω = 2πf, f is frequency, t is time, A is a constant of −1 <A <0, n is a positive integer, and δθ is a phase.
The actuator according to claim 4, wherein n = 3.
The actuator according to claim 4, wherein n = 2.
2. The actuator according to claim 1, wherein the electromechanical conversion unit reciprocates linearly the end of the driver along the moving direction of the driver by the displacement of the plurality of displacements.
Each of the plurality of displacement portions has a higher moving speed of the end of the driver in the direction opposite to the moving direction than a moving speed of the end of the driver in the moving direction of the mover. The actuator according to claim 7, wherein the actuator is displaced as follows.
The plurality of displacement parts include a pair of expansion and contraction parts arranged side by side in the moving direction of the mover,
One of the pair of expansion / contraction parts is applied with a driving voltage V1 having a waveform represented by the following expression (1), and the other of the pair of expansion / contraction parts has a driving voltage having a waveform represented by the following expression (2). The actuator according to claim 7, which expands and contracts when V2 is applied.
V1 = sin (ωt) + Asin (n × ωt) (1)
V2 = sin (ωt + δθ) −Asin (n × (ωt + δθ)) (2)
However, ω = 2πf, f is frequency, t is time, A is a constant of −1 <A <0, n is a positive integer, and δθ is a phase.
10. The actuator according to claim 9, wherein n = 2.
The actuator according to claim 9, wherein n = 3.
2. The actuator according to claim 1, wherein the driving element is a protrusion that extends from the electromechanical conversion unit side toward the moving element in a direction intersecting a moving direction of the moving element.
The actuator according to any one of claims 1 to 12, and
A rotor as the mover that is rotated by the actuator;
A drive device comprising:
The actuator according to any one of claims 1 to 12, and
A slider as a mover that is linearly moved by the actuator;
A drive device comprising:
The drive device according to claim 13 or 14, and
An optical member that is moved in the optical axis direction by the driving device;
A lens unit comprising:
The drive device according to claim 13 or 14, and
An optical member that is moved in the optical axis direction by the driving device;
An imaging unit that captures an image formed by the optical member;
An imaging apparatus comprising:
A driving element arranged to come into contact with the moving element;
A plurality of displacement portions that are arranged side by side in the moving direction of the moving element and are displaced at different phases in a direction that intersects the moving direction of the moving element when electric power is supplied. An operation method of an actuator for moving the moving element in the moving direction,
Actuating method for moving actuator by linearly moving in the moving direction of the moving element in a state where the moving element side end of the driving element is in contact with the moving element by displacing the plurality of displacement parts .