JP2021010209A - Vibration wave actuator and electronic apparatus with the same - Google Patents

Abstract

To provide a vibration wave actuator comprising a hold mechanism which performs holding in such a manner that vibration generated in a vibration body can be efficiently transferred to a contact body in the case where a direction in which projections are formed is different from a direction in which the vibration body or the contact body is driven.SOLUTION: A vibration wave actuator comprises: a vibration body including an elastic body in which a plurality of projections is formed in a first direction, and an electromechanical energy conversion element which is bonded to the elastic body; a contact body in contact with the plurality of projections; and a first hold mechanism which holds any one of the vibration body and the contact body. The other of the vibration body and the contact body can be driven in a second direction which crosses the first direction. The first hold mechanism holds any one of the vibration body and the contact body in a rotatable manner around the second direction, and regulates the rotation of any one of the vibration body and the contact body around the first direction.SELECTED DRAWING: Figure 4

Description

The present invention relates to a vibration wave actuator and an electronic device having the same.

Conventionally, a vibration wave actuator capable of generating a vibration in an electric-mechanical energy conversion element (piezoelectric element) bonded to an elastic body to drive a driven body (hereinafter, also referred to as a “contact body”) in contact with the elastic body. Has been proposed. As such a vibration wave actuator, the vibration wave actuator described in Patent Document 1 has been proposed. The elastic body described in Patent Document 1 has a structure in which two contact portions (hereinafter, also referred to as “projections”) are formed in a direction orthogonal to the direction in which the driven body is driven.

The vibration mode of the elastic body 20 described in Patent Document 1 will be described. FIG. 8 is a perspective view illustrating two bending vibration modes that excite the elastic body 20. FIG. 9 is a front view illustrating two bending vibration modes that excite the elastic body 20. The elastic body 20 shown in FIGS. 8 and 9 has a simplified shape so that the vibration mode can be easily explained. Further, the X-axis direction (hereinafter, also referred to as “X direction”), the Y-axis direction (hereinafter, also referred to as “Y direction”) and the Z-axis direction (hereinafter, also referred to as “Z direction”) are three-dimensional Cartesian coordinates. It represents a system. The two protrusions are formed in the Y direction.

The vibration of one of the two bending vibration modes (hereinafter, also referred to as “mode A”) is the first-order bending vibration in the X direction. As shown in FIG. 8, the two protrusions 11c and 11c are arranged in the vicinity of the positions that are the antinodes of the vibration of the mode A, so that the vibration of the mode A causes the reciprocating motion in the Z direction in the same phase. Do. The vibration of the other of the two bending vibrations (hereinafter, also referred to as "mode B") is a secondary torsional vibration. The two protrusions 11c and 11c reciprocate in the X direction in the same phase due to the vibration of mode B.

By exciting the vibrations of modes A and B in different phases, elliptical motion is generated at the tips of the two protrusions 11c and 11c. This elliptical motion drives the driven body (not shown) in the X direction. By switching the locus of elliptical motion between the forward direction and the reverse direction, the direction of relative movement can be switched.

Further, Patent Document 2 proposes a holding mechanism for a vibrating body (having an elastic body and a piezoelectric element) used in a vibrating wave actuator.

JP-A-2017-127154 Japanese Unexamined Patent Publication No. 2006-301454

In order to efficiently drive the vibration wave actuator described in Patent Document 1 with the driven body, a holding mechanism that efficiently and easily transmits the vibration generated in the vibrating body to the driven body is required.

If the vibrating body 20 described with reference to FIGS. 8 and 9 has a substantially symmetrical shape in the X direction and the Y direction, the locus of elliptical motion is generated symmetrically on the YZ plane in the forward direction and the opposite direction. Relative movement in the minus (-) X direction has the same performance. However, if the vibrating body 20 is tilted about the Y-axis with respect to the driven body, the driving force for driving the driven body differs between the X direction and the −X direction, resulting in a directional difference in the driving performance. Therefore, it is necessary to maintain the vibrating body 20 in a desired state without tilting it around the Y-axis.

The present invention has a holding mechanism that holds the vibration generated in the vibrating body so that it can be efficiently transmitted to the contact body when the direction in which the protrusion is formed is different from the direction in which the vibrating body or the contact body is driven. It is to provide a wave actuator.

In order to solve the above problems, the vibration wave actuator of the present invention includes an elastic body in which a plurality of protrusions are formed in the first direction, and an electro-mechanical energy conversion element bonded to the elastic body. A vibrating body, a contact body that comes into contact with the plurality of protrusions, and a first holding mechanism that holds one of the vibrating body and the contact body, and the vibrating body and the contact body. A vibration wave actuator capable of driving the other of them in a second direction intersecting the first direction, and the first holding mechanism uses either one of the vibrating body and the contacting body. It is characterized in that it is rotatably held in the second direction and the rotation of either one of the vibrating body and the contact body is regulated in the first direction.

According to the present invention, when the direction in which the protrusion is formed and the direction in which the vibrating body or the contact body is driven are different, a holding mechanism that efficiently and easily transmits the vibration generated in the vibrating body to the contact body is provided. It is possible to provide a vibration wave actuator having.

It is a perspective view which shows the component of the vibration wave actuator which concerns on 1st Embodiment of this invention. It is an exploded perspective view which shows the component of the vibration wave actuator which concerns on 1st Embodiment of this invention. It is a perspective view which shows the component of the drive unit and peripheral parts which concerns on 1st Embodiment of this invention. It is an exploded perspective view which shows the component of the drive unit and peripheral parts which concerns on 1st Embodiment of this invention. It is a side view of the vibration wave actuator which concerns on 1st Embodiment of this invention. It is sectional drawing of the drive unit and contact body which concerns on 1st Embodiment of this invention. It is (a) side view and (b) block diagram which show the component of the electronic device (imaging apparatus) provided with a vibration wave actuator. It is a perspective view explaining two bending vibration modes exciting a vibrating body. It is a side view explaining two bending vibration modes exciting a vibrating body.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a perspective view showing a component of the vibration wave actuator 1 according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view showing a component of the vibration wave actuator 1 according to the first embodiment of the present invention.

As shown in FIGS. 1 and 2, the vibration wave actuator 1 is mainly composed of a base member 4, a drive unit 21, a moving unit 22, a round bar-shaped first guide bar 7, and a second guide bar 8.

The first guide bar 7 and the second guide bar 8 are held by the base member 4 and the guide holding member 5. The first guide bar 7 and the second guide bar 8 may be completely fixed to the base member 4. The first guide bar 7 and the second guide bar 8 are arranged so that their axes are parallel to each other. In FIGS. 1 and 2, this axial direction is hereinafter referred to as a "second direction". The second direction coincides with the X-axis direction in the first embodiment.

As shown in FIG. 2, the base member 4 and the drive unit holding component 6 form a second holding member, and the second holding member holds the drive unit 21. The drive unit 21 is rotatably held around the base member 4 and the X-axis shown in the drawing. The holding mechanism related to this holding will be described later.

The moving unit 22 is composed of a moving member 3 and a contact body 9. The contact body 9 is a member that comes into contact with the vibrating body 20 described later. Here, the "contact body" refers to a member that comes into contact with the vibrating body and moves relative to the vibrating body due to the vibration generated in the vibrating body. The contact between the contact body and the vibrating body is not limited to the direct contact in which no other member is interposed between the contact body and the vibrating body. The contact between the contact body and the vibrating body is an indirect contact in which another member intervenes between the contact body and the vibrating body if the contact body moves relative to the vibrating body due to the vibration generated in the vibrating body. May be good.

The "other member" is not limited to a member (thin paper or the like) independent of the contact body and the vibrating body. The "other member" may be a surface-treated portion formed on the contact body or the vibrating body by plating, nitriding treatment, or the like.

A cylindrical hole is formed in the moving member 3 as a guide, and is fitted into the first guide bar 7 and held so as to be movable in the X-axis direction. Further, the moving member 3 is formed with a portion that sandwiches the second guide bar 8, and restricts the moving unit 22 from rotating around the axis of the first guide bar 7. By being held in this way, the moving unit 22 can move only in the X-axis direction with respect to the base member 4.

A pressing force, which will be described later, is applied to the drive unit 21 and the moving unit 22. This pressing force is applied in a direction that substantially coincides with the X direction represented as the second direction and the Z direction that is orthogonal to the Y direction (described later). The direction in which the pressing force is applied (the direction in which the pressure is applied) is hereinafter referred to as the "third direction".

FIG. 3 is a perspective view showing the components of the drive unit 21 according to the first embodiment of the present invention. FIG. 4 is an exploded perspective view showing the components of the drive unit 21 according to the first embodiment of the present invention.

The vibrating body 20 is composed of an elastic body 11 and a piezoelectric element 12 (electrical-mechanical energy conversion element). Further, the vibrating body 20 includes an electrical connection member (not shown) with the outside.

The elastic body 11 includes a rectangular plate-shaped vibrating portion 11a, two support portions 11b, and two protrusions 11c and 11c. A plurality of (here, two) protrusions 11c and 11c are formed in a predetermined direction, and this direction is hereinafter referred to as a "first direction". The first direction coincides with the Y direction in the first embodiment. The two protrusions 11c and 11c are formed at positions facing each other near the edge of the vibrating portion 11a in the Y direction in the drawing, and extend in the Z direction (orthogonal to the X and Y directions) in the drawing. That is, the two protrusions 11c and 11c are formed so as to be aligned in the Y direction in the drawing. The two support portions 11b and 11b are formed so as to extend from the vibrating portion 11a in the X direction in the drawing so as to face each other. The vibration mode generated in the vibrating body 20 is the same as that described in the background art with reference to FIGS. 8 and 9.

Since the two protrusions 11c and 11c are aligned in the Y direction, the vibrating body 20 can determine the posture of the vibrating body 20 when the protrusions 11c and 11c come into contact with other parts in terms of rotation around the X axis. On the other hand, with respect to the Y-axis circumference, the vibrating body 20 alone is not stable, and a mechanism for holding the vibrating body 20 to stabilize the posture is required. The posture around the Y-axis needs to be stable without changing even in the stationary state and the driving state. The holding mechanism that gives the vibrating body 20 a desired posture will be described below.

As shown in FIG. 4, the base component 13 has four holding portions 13b extending downward in the Z direction from the main body 13a and the main body 13a, and conical recesses on both end surfaces in the X direction in the drawing. The two joint portions 13c and 13c (first recesses) formed are formed.

The vibrating body 20 is held by joining the connecting portion 13b of the base component 13 and the supporting portion 11b of the elastic body 11. Further, a rectangular permanent magnet 14 (first urging member) is held and fixed on the lower surface side of the main body portion 13a of the base component 13 in the Z direction. The permanent magnet 14 is arranged so as not to come into contact with the elastic body 11.

The vibrating body 20, the permanent magnet 14, and the base component 13 are integrated to form the vibrating body unit 2. The first holding member 15 (first holding member) and the second holding part 16 (first holding member) constitute the first holding member, and the first holding member holds the vibrating body unit 2.

The first holding component 15 extends in the main body portion 15a, the fitting shaft 15b (second convex portion) extending in the X direction, the substantially spherical holding portion 15c (first convex portion), and the X direction. It is composed of two fitting holes 15d.

The second holding component 16 extends in the main body portion 16a, the fitting shaft 16b (second convex portion) extending in the X direction, the substantially spherical holding portion 16c (first convex portion), and the X direction. It is composed of a fitting shaft 16d.

The first holding component 15 and the second holding component 16 are restricted from moving in directions other than the X direction by fitting the fitting hole 15d and the fitting shaft 16d.

The holding portions 15c and 16c of the first holding component 15 and the second holding component 16 are combined with the coupling portions 13c and 13c of the vibrator holding component 13, respectively, to form two coupling portions P1 and P2.
The first holding mechanism is formed by combining the holding portions 15c and 16c of the first holding component 15 and the second holding component 16 with the coupling portions 13c and 13c of the vibrator holding component 13, respectively. The coupling portions P1 and P2 are collectively referred to as the first holding mechanism. An urging force in the X direction is applied to the coupling portions P1 and P2 to perform coupling without rattling. The virtual axis A1 connecting the two coupling portions P1 and P2 has two coupling portions P1 and P2 arranged in parallel with the X axis in the drawing, so that the vibrating body unit 2 (including the vibrating body 20) can be formed. , Is freely rotated around the axis A1 parallel to the X direction.

The drive unit 21 is composed of the vibrating body unit 2, the first holding component 15, and the second holding component 16. The moving unit 22 (including the contact body 9) can be driven by the elliptical motion generated in the vibrating body unit 2 (including the vibrating body 20).

As shown in FIG. 3, an elastic component 17 (second urging member), which is a compression coil spring, is fitted into the fitting shaft 15b of the first holding component 15. The fitting shaft 15b is inserted into the fitting hole 4a (second recess) of the base member 4 shown in FIG. 2 to form the joint portion P3. At this time, the elastic component 17 is held in a compressed state.

The fitting shaft 16b of the second holding component 16 is inserted into the fitting hole 6a (second recess) of the drive unit holding component 6 to form the coupling portion P4. The fitting shaft 15b of the first holding component 15 is combined with the fitting hole 4a of the base member 4, and the fitting shaft 16b of the first holding component 15 is combined with the fitting hole 6a of the drive unit holding component 6. , A second holding mechanism is formed. The coupling portions P3 and P4 are collectively referred to as a second holding mechanism. The virtual axis A2 connecting the coupling portions P3 and P4 is arranged parallel to the X direction in the drawing, so that the drive unit 21 is freely rotatably held around the axis A2 parallel to the X direction.

As described above, the elastic component 17 is deformed in the compression direction to generate an elastic force in the X direction. This elastic force acts in a direction in which the first holding component 15 and the second holding component 16 are relatively close to each other, and this force acts in a direction in which the components constituting the joints P1 and P2 are pressed together. Further, this elastic force also acts as a force for pressing the second holding component 16 and the drive unit holding component 6 at the joint portion P3. By this action, in each of the connecting portions P1 to P4, the parts are combined without rattling, and the vibrating body unit 2 and the driving unit 21 are held without rattling in the X direction.

FIG. 5 is a side view of the vibration wave actuator 1 according to the first embodiment of the present invention. In FIG. 5, some component parts are not shown for easy explanation.

As described above, the drive unit 21 is rotatably held on the axis A2 parallel to the X direction, and in the case of a small amount of rotation, the vibrating body unit 2 is movably held in the Z direction. .. Further, the vibrating body unit 2 is freely rotatably held on the axis A1 parallel to the X direction. From these configurations, the vibrating body unit 2 can be displaced in the Z direction and rotated around the X axis, and movement in the X and Y directions and rotation around the Y and Z axes, which are other degrees of freedom, are constrained ( Regulated) and retained.

The shaft A1 is arranged so as to be near the center in the Y direction in the drawing with respect to the vibrating body unit 2, and when the vibrating body unit 2 rotates around the shaft A1, the two protrusions 11c and 11c are substantially the same. It becomes the amount of movement.

The first holding component 15, the second holding component 16, and the moving unit 22 are arranged so as not to projectively overlap in the X direction in the drawing, and secure the moving amount of the vibration wave actuator 1 during operation. .. Further, miniaturization is possible by arranging the shaft A1 so as to be above the protrusion 11c in the Z direction in the drawing.

FIG. 6 is a cross-sectional view showing a magnetic attraction state by the vibrating body unit 2 and the contact body 9 according to the first embodiment of the present invention. This figure shows a cross section in the YZ plane including the center of the vibrating body unit 2.

The permanent magnet component 14 is magnetized in the Z direction in the drawing, and the magnetic flux line I in the permanent magnet component 14 is also generated in the substantially Z direction. The magnetic flux line I generated by the permanent magnet component 14 passes through the contact body 9 and the elastic body 11 mainly formed of the ferromagnetic material, and is formed in a loop shape. The position of the permanent magnet component 14 is determined integrally with the vibrating body 20 which is a part of the vibrating body unit 2 and is also a component constituting the vibrating body unit 2. The vibrating body unit 2 and the contact body 9 are attracted by the magnetic action described here.

The explanation will be continued by returning to FIG.

The contact body 9 is fixed in the Z direction via the moving member 3, while the vibrating body unit 2 is movable in the Z direction as described above, so that the attractive force due to the magnetic action is elastic with the contact body 9. It acts as a pressing force between the body 11 and the protrusion 11c.

Further, the vibrating body unit 2 can rotate around the X axis (around the second direction), and the two protrusions 11c and 11c can be brought into contact with each other without bias to pressurize.

As described above, the rotation of the vibrating body unit 2 around the Y axis (around the first direction) is restricted (regulated), and the performance deteriorates and the performance becomes unstable due to the vibrating body unit 2 tilting around the Y axis. It is possible to realize a vibration wave actuator that can obtain stable performance without causing the above.

In the first embodiment, the second direction is orthogonal to the first direction, but the second direction may intersect the first direction. Further, the third direction is orthogonal to the first direction and the second direction, but may intersect the first direction and the second direction.

<Second embodiment>
The vibration wave actuator 1 described above can be used, for example, in an image pickup device (optical device) in which a lens group or an image pickup element is a driven member driven by a vibrating body or a contact body. Further, the stage can be used for various purposes such as an electronic device such as a linear motion stage device in which a driven member is driven by a vibrating body or a contact body. Here, as an example, an imaging device (optical device) in which the vibration wave actuator 1 is arranged in the lens barrel and used to drive a lens group having one or a plurality of lenses will be described.

FIG. 7A is a top view showing a schematic configuration of the image pickup apparatus 700. The image pickup device 700 includes a camera body 730 equipped with an image pickup element 710 and a power button 720. Further, the image pickup apparatus 700 includes a first lens group (not shown), a second lens group 320, a third lens group (not shown), a fourth lens group 340, and vibration type drive devices 620, 640 (vibration). A lens barrel 740 with a wave actuator) is provided. The lens barrel 740 is removable as an interchangeable lens from the camera body 730.

In the image pickup apparatus 700, the second lens group 320 (driven member) and the fourth lens group 340 (driven member) are driven by the two vibration wave actuators 620 and 640, respectively. As the vibration wave actuators 620 and 640, the vibration wave actuator 1 described with reference to FIGS. 1 to 7 is used.

FIG. 7B is a block diagram showing a schematic structure of the image pickup apparatus 700. The first lens group 310, the second lens group 320, the third lens group 330, the fourth lens group 340, and the light amount adjusting unit 350 are arranged at predetermined positions on the optical axis inside the lens barrel 740. There is. The light that has passed through the first lens group 310 to the fourth lens group 340 and the light amount adjusting unit 350 is imaged on the image sensor 710. The image sensor 710 converts an optical image into an electric signal and outputs it, and the output is sent to the camera processing circuit 750.

The camera processing circuit 750 amplifies, gamma-corrects, and the like the output signal from the image sensor 710. The camera processing circuit 750 is connected to the CPU 790 via the AE gate 755, and is connected to the CPU 790 via the AF gate 760 and the AF signal processing circuit 765. The video signal subjected to the predetermined processing in the camera processing circuit 750 is sent to the CPU 790 through the AE gate 755, the AF gate 760, and the AF signal processing circuit 765. The AF signal processing circuit 765 extracts a high frequency component of the video signal, generates an evaluation value signal for autofocus (AF), and supplies the generated evaluation value to the CPU 790.

The CPU 790 is a control circuit that controls the overall operation of the image pickup apparatus 700, and generates a control signal for exposure determination and focusing from the acquired video signal. The CPU 790 controls the drive of the vibration wave actuators 620, 640 and the meter 630 so that the determined exposure and the appropriate focus state can be obtained. As a result, the positions of the second lens group 320, the fourth lens group 340, and the light amount adjusting unit 350 in the optical axis direction are adjusted. Under the control of the CPU 790, the vibration wave actuator 620 moves the second lens group 320 in the optical axis direction, the vibration wave actuator 640 moves the fourth lens group 340 in the optical axis direction, and the light amount adjusting unit 350 is a meter. It is driven and controlled by 630.

The position in the optical axis direction of the second lens group 320 driven by the vibration wave actuator 620 is detected by the first linear encoder 770. Further, when the detection result is notified to the CPU 790, it is fed back to the drive of the vibration wave actuator 620.

Similarly, the position in the optical axis direction of the fourth lens group 340 driven by the vibration wave actuator 640 is detected by the second linear encoder 775. Further, when the detection result is notified to the CPU 790, it is fed back to the drive of the vibration wave actuator 640. The position of the light amount adjusting unit 350 in the optical axis direction is detected by the aperture encoder 780, and the detection result is notified to the CPU 790, so that the position is fed back to the drive of the meter 630.

<Other embodiments>
In the first embodiment, the first holding mechanism holds the vibrating body unit (including the vibrating body) and the moving unit (including the contact body). Further, of the vibrating body unit (including the vibrating body) and the moving unit (including the contact body), the moving unit can be driven. However, the first holding mechanism may hold the moving unit among the vibrating body unit (including the vibrating body) and the moving unit (including the contact body). Further, of the vibrating body unit (including the vibrating body) and the moving unit (including the contact body), the vibrating unit may be driveable.

Although the present invention has been described in detail based on the preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various embodiments within the scope of the gist of the present invention are also present. Included in the invention. Further, each of the above-described embodiments is merely an embodiment of the present invention, and each embodiment can be combined as appropriate.

1 Vibration wave actuator 9 Driven body (contact body)
11 Elastic body 11c Protrusion 12 Piezoelectric element (electrical-mechanical energy conversion element)
P1, P2 First holding mechanism 20 Vibrating body

Claims (12)

A vibrating body having an elastic body having a plurality of protrusions formed in the first direction and an electric-mechanical energy conversion element bonded to the elastic body.
A contact body that comes into contact with the plurality of protrusions,
A first holding mechanism for holding either the vibrating body or the contact body is provided.
A vibration wave actuator capable of driving the other of the vibrating body and the contacting body in a second direction intersecting the first direction.
The first holding mechanism is
One of the vibrating body and the contact body is rotatably held around the second direction, and one of the vibrating body and the contact body is in the first direction. An oscillating wave actuator characterized by regulating rotation around it. The vibrating body or the contact body has a first urging member.
A claim characterized in that either one of the vibrating body and the contact body is urged by the first urging member in a direction intersecting the first direction and the second direction. Item 1. The vibration wave actuator according to item 1. The vibration wave actuator according to claim 2, wherein the first direction and the direction intersecting the second direction are directions around the second direction. The vibration wave actuator according to claim 2 or 3, wherein the first urging member is a permanent magnet. Having a first holding member having a part of the first holding mechanism,
The first holding mechanism includes a first convex portion extending in the second direction of the first holding member, and one of the vibrating body and the contact body. The vibration wave actuator according to any one of claims 1 to 4, further comprising a first concave portion that fits with one convex portion. A second holding mechanism for holding the first holding member is provided.
The second holding mechanism rotatably holds the first holding member in a direction intersecting the first direction and the second direction, and the first holding member of the first holding member. The vibration wave actuator according to claim 5, wherein the rotation around the first direction is regulated. The second holding mechanism has a second urging member.
The vibration wave actuator according to claim 6, wherein the first holding mechanism is urged in the second direction by the second urging member. The vibration wave actuator according to claim 7, wherein the second urging member is a coil spring. Having a second holding member having a part of the second holding mechanism,
The second holding mechanism is fitted with the second convex portion of the first holding member, which extends in the second direction, and the second convex portion of the second holding member. The vibration wave actuator according to any one of claims 6 to 8, further comprising a second recess. The vibration wave actuator according to any one of claims 1 to 9, wherein the second direction is orthogonal to the first direction. The vibration wave actuator according to any one of claims 1 to 10.
An image pickup apparatus comprising: a lens group or an image pickup element driven by the vibrating body and the other of the contact bodies. The vibration wave actuator according to any one of claims 1 to 10.
An electronic device comprising: a driven member driven by the vibrating body and the other of the contacting bodies.

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